The main theme of this paper is to reduce noise fro
m the noisy composite signal and reconstruct the in
put
signals from the composite signal by designing FIR
digital filter bank. In this work, three sinusoidal
signals
of different frequencies and amplitudes are combine
d to get composite signal and a low frequency noise
signal is added with the composite signal to get no
isy composite signal. Finally noisy composite signa
l is
filtered by using FIR digital filter bank to reduce
noise and reconstruct the input signals
Asymmetric recursive Gaussian filtering for space-variant artificial bokehTuan Q. Pham
This document describes an asymmetric recursive Gaussian filter for space-variant artificial bokeh. The filter approximates two-dimensional space-variant blur using separable one-dimensional Gaussian filtering along the x- and y- dimensions. Within each dimension, the Gaussian filter is approximated by parallel forward and backward infinite impulse response (IIR) filters. The filter reduces intensity leakage at blur discontinuities by modifying the blur sigma of the IIR filters differently for the forward and backward passes as they approach discontinuities, resulting in an asymmetric space-variant filter. This asymmetric recursive filter is able to produce visually pleasing background blur for scenes with contents at different depths without smearing artifacts.
This document discusses decimation and interpolation using polyphase filters. It begins by defining decimation and interpolation and describing how decimators use anti-aliasing filters followed by downsamplers, while interpolators use upsamplers followed by anti-imaging filters. It then presents the principles of polyphase decimation and interpolation, showing how they can be represented in both the time and z-transform domains. This allows implementing decimators and interpolators more efficiently using fewer filter operations and less memory than traditional implementations.
Estimation of Separation and Location of Wave Emitting Sources : A Comparison...sipij
This document compares the Burg method and Fourier transform method for estimating the separation and location of wave emitting sources. The Burg method provides higher resolution than the Fourier transform method and can better resolve adjacent sources. Simulation results show the Burg method more accurately estimates source separation and location, especially when the separation distance is small or noise is present. The percentage error is smaller for the Burg method compared to the Fourier transform method.
This document summarizes a research paper that compares different digital filtering techniques for removing noise from electrocardiogram (ECG) signals. It describes how finite impulse response (FIR) filters were designed using various windowing techniques, including rectangular, Hamming, Hanning, and Blackman windows. Infinite impulse response (IIR) filters and wavelet transforms were also evaluated for denoising ECG signals. The performance of the different filtering approaches were compared based on the power spectral density and average power of the signals before and after filtering. The paper found that an FIR filter designed with the Kaiser window showed the best results for noise removal from ECG signals.
The document provides an overview of adaptive filters. It discusses that adaptive filters are digital filters that have self-adjusting characteristics to changes in input signals. They have two main components: a digital filter with adjustable coefficients and an adaptive algorithm. Common adaptive algorithms are LMS and RLS. Adaptive filters are used for applications like noise cancellation, system identification, channel equalization, and signal prediction. The key aspects of adaptive filter theory and algorithms like LMS, RLS, Wiener filters are also covered.
This document summarizes a presentation on multirate digital signal processing. Multirate systems involve processing signals at different sampling rates, using operations like decimation to lower the sampling rate and interpolation to increase it. Decimation involves downsampling by discarding samples, while interpolation involves upsampling by inserting zeros. These operations are used for applications like sampling rate conversion, audio/video encoding, and communications systems. Key aspects of multirate signal processing discussed include anti-alias filtering, sampling rate conversion using cascaded decimation and interpolation, and choosing optimal filter designs.
Design of an Adaptive Hearing Aid Algorithm using Booth-Wallace Tree MultiplierWaqas Tariq
The paper presents FPGA implementation of a spectral sharpening process suitable for speech enhancement and noise reduction algorithms for digital hearing aids. Booth and Booth Wallace multiplier is used for implementing digital signal processing algorithms in hearing aids. VHDL simulation results confirm that Booth Wallace multiplier is hardware efficient and performs faster than Booth’s multiplier. Booth Wallace multiplier consumes 40% less power compared to Booth multiplier. A novel digital hearing aid using spectral sharpening filter employing booth Wallace multiplier is proposed. The results reveal that the hardware requirement for implementing hearing aid using Booth Wallace multiplier is less when compared with that of a booth multiplier. Furthermore it is also demonstrated that digital hearing aid using Booth Wallace multiplier consumes less power and performs better in terms of speed.
Design and determination of optimum coefficients of iir digital highpass filt...Subhadeep Chakraborty
This document describes a technique for designing an Infinite Impulse Response (IIR) digital highpass filter. The technique involves first designing an analog highpass filter using passive components like resistors and capacitors. Then, an analog-to-digital mapping technique is applied to convert the analog filter design into an equivalent digital filter transfer function in the z-domain. This provides the numerator and denominator coefficients needed for the digital IIR filter. The document presents the process and equations for realizing the IIR digital filter and determining its transfer function from which the filter coefficients can be obtained. A flowchart outlines the overall steps of the proposed algorithm.
Asymmetric recursive Gaussian filtering for space-variant artificial bokehTuan Q. Pham
This document describes an asymmetric recursive Gaussian filter for space-variant artificial bokeh. The filter approximates two-dimensional space-variant blur using separable one-dimensional Gaussian filtering along the x- and y- dimensions. Within each dimension, the Gaussian filter is approximated by parallel forward and backward infinite impulse response (IIR) filters. The filter reduces intensity leakage at blur discontinuities by modifying the blur sigma of the IIR filters differently for the forward and backward passes as they approach discontinuities, resulting in an asymmetric space-variant filter. This asymmetric recursive filter is able to produce visually pleasing background blur for scenes with contents at different depths without smearing artifacts.
This document discusses decimation and interpolation using polyphase filters. It begins by defining decimation and interpolation and describing how decimators use anti-aliasing filters followed by downsamplers, while interpolators use upsamplers followed by anti-imaging filters. It then presents the principles of polyphase decimation and interpolation, showing how they can be represented in both the time and z-transform domains. This allows implementing decimators and interpolators more efficiently using fewer filter operations and less memory than traditional implementations.
Estimation of Separation and Location of Wave Emitting Sources : A Comparison...sipij
This document compares the Burg method and Fourier transform method for estimating the separation and location of wave emitting sources. The Burg method provides higher resolution than the Fourier transform method and can better resolve adjacent sources. Simulation results show the Burg method more accurately estimates source separation and location, especially when the separation distance is small or noise is present. The percentage error is smaller for the Burg method compared to the Fourier transform method.
This document summarizes a research paper that compares different digital filtering techniques for removing noise from electrocardiogram (ECG) signals. It describes how finite impulse response (FIR) filters were designed using various windowing techniques, including rectangular, Hamming, Hanning, and Blackman windows. Infinite impulse response (IIR) filters and wavelet transforms were also evaluated for denoising ECG signals. The performance of the different filtering approaches were compared based on the power spectral density and average power of the signals before and after filtering. The paper found that an FIR filter designed with the Kaiser window showed the best results for noise removal from ECG signals.
The document provides an overview of adaptive filters. It discusses that adaptive filters are digital filters that have self-adjusting characteristics to changes in input signals. They have two main components: a digital filter with adjustable coefficients and an adaptive algorithm. Common adaptive algorithms are LMS and RLS. Adaptive filters are used for applications like noise cancellation, system identification, channel equalization, and signal prediction. The key aspects of adaptive filter theory and algorithms like LMS, RLS, Wiener filters are also covered.
This document summarizes a presentation on multirate digital signal processing. Multirate systems involve processing signals at different sampling rates, using operations like decimation to lower the sampling rate and interpolation to increase it. Decimation involves downsampling by discarding samples, while interpolation involves upsampling by inserting zeros. These operations are used for applications like sampling rate conversion, audio/video encoding, and communications systems. Key aspects of multirate signal processing discussed include anti-alias filtering, sampling rate conversion using cascaded decimation and interpolation, and choosing optimal filter designs.
Design of an Adaptive Hearing Aid Algorithm using Booth-Wallace Tree MultiplierWaqas Tariq
The paper presents FPGA implementation of a spectral sharpening process suitable for speech enhancement and noise reduction algorithms for digital hearing aids. Booth and Booth Wallace multiplier is used for implementing digital signal processing algorithms in hearing aids. VHDL simulation results confirm that Booth Wallace multiplier is hardware efficient and performs faster than Booth’s multiplier. Booth Wallace multiplier consumes 40% less power compared to Booth multiplier. A novel digital hearing aid using spectral sharpening filter employing booth Wallace multiplier is proposed. The results reveal that the hardware requirement for implementing hearing aid using Booth Wallace multiplier is less when compared with that of a booth multiplier. Furthermore it is also demonstrated that digital hearing aid using Booth Wallace multiplier consumes less power and performs better in terms of speed.
Design and determination of optimum coefficients of iir digital highpass filt...Subhadeep Chakraborty
This document describes a technique for designing an Infinite Impulse Response (IIR) digital highpass filter. The technique involves first designing an analog highpass filter using passive components like resistors and capacitors. Then, an analog-to-digital mapping technique is applied to convert the analog filter design into an equivalent digital filter transfer function in the z-domain. This provides the numerator and denominator coefficients needed for the digital IIR filter. The document presents the process and equations for realizing the IIR digital filter and determining its transfer function from which the filter coefficients can be obtained. A flowchart outlines the overall steps of the proposed algorithm.
This document contains 5 problems related to digital signal processing. Problem 1 involves designing a 25-tap finite impulse response (FIR) filter to approximate an ideal bandpass frequency response and plotting the filter's magnitude and phase response. Problem 2 repeats this for a bandstop filter. Problem 3 converts an analog filter to a digital infinite impulse response (IIR) filter using impulse invariance. Problem 4 does the same conversion using bilinear transformation. Problem 5 compares the two conversion methods and discusses their restrictions.
The document discusses digital filters and their design process. It explains that the design process involves four main steps: approximation, realization, studying arithmetic errors, and implementation.
For approximation, direct and indirect methods are used to generate a transfer function that satisfies the filter specifications. Realization generates a filter network from the transfer function. Studying arithmetic errors examines how quantization affects filter performance. Implementation realizes the filter in either software or hardware.
The document also outlines the basic building blocks of digital filters, including adders, multipliers, and delay elements. It introduces linear time-invariant digital filters and explains their input-output relationship using difference equations and the z-transform.
The document reports on a subjective comparison of 13 speech enhancement algorithms conducted by Dynastat, Inc. using the ITU-T P.835 methodology. The algorithms encompassed four classes: spectral subtractive, subspace, statistical-model based, and Wiener. A noisy speech corpus called NOIZEUS was developed with IEEE sentences corrupted by 8 noises at varying SNRs. For the subjective tests, enhanced speech from 20 sentences in 4 noises at 2 SNRs was evaluated based on signal distortion, noise distortion, and overall quality. The statistical-model based methods performed best overall, followed by a multi-band spectral subtraction method. Incorporating noise estimation did not significantly improve performance for some algorithms.
A new two stage FxNLMS algorithm based ANC system with secondary path modelling was proposed in
[15].Performance analysis of this system with real signals has been carried out using computer simulation.
Simulation studies showed that the system after trained with WGN can be successfully used for reducing
wide sense broad band noise.This paper also explores the intelligibility of speech signals in the quiet zone
created by the ANC system. The utterances of phonetically balanced Harvard sentences with different
SNRs are propagated through the quiet zone and the intelligibility of the resultant speech signal is
measured using MOS (Mean Opinion Score) test. Encouraging results are obtained which indicates that
the two stage FxNLMS algorithm based ANC system can find application in mobile phone communication.
This document discusses baseband shaping for data transmission. It introduces several digital modulation formats used for discrete PAM signals like unipolar, polar, bipolar and Manchester encoding. It then discusses factors that affect transmission like DC component, bandwidth, bit synchronization and error detection. It describes intersymbol interference and its causes like multipath propagation and bandlimited channels. It presents the baseband binary data transmission system model. Nyquist's criterion for zero ISI is defined. Practical solutions like raised cosine filters are discussed. The transmission bandwidth requirement is derived based on the rolloff factor. Finally, it describes what an eye diagram reveals about the system performance.
Analysis of Adaptive and Advanced Speckle Filters on SAR DataIOSRjournaljce
Synthetic Aperture RADAR(SAR) images get inherently affected by speckle noise which is multiplicative in nature. This noise affects the image spatial statistics and properties. Over the past several years, many SAR denoising algorithms have been developed to reduce speckle noise. Some of the standard speckle filters are Gamma MAP, Lee, Frost and Kuan filters. Further, these have also been modified to obtain better results after filtering, than their original counterparts. Apart from the standard speckle filters, advanced SAR filters like Block Matching 3 Dimensional (BM3D) are also present. In this paper several standard as well as advanced speckle filters have been analyzed and compared. For comparison, Quality Assessment has been performed where the filtered images are compared to each other using parameters like Radiometric Resolution and others. These parameters help to distinguish the performance of the filters on basis of signal strength, speckle reduction, mean preservation and edge and feature preservation. In the paper, radiometric resolution, speckle index and mean preservation index will be used to analyze among the performance of the filters.
I am Felix T. I am a Digital Signal Processing Assignment Expert at matlabassignmentexperts.com. I hold a Ph.D. in Matlab, University of Greenwich, UK. I have been helping students with their homework for the past 4 years. I solve assignments related to Digital Signal Processing.
Visit matlabassignmentexperts.com or email info@matlabassignmentexperts.com.
You can also call on +1 678 648 4277 for any assistance with Digital Signal Processing Assignments.
The document reports on a digital signal processing project to design and compare different types of FIR and IIR filters. FIR filters designed include a least squares filter and an equiripple filter. IIR filters designed include a Butterworth filter and a Chebyshev type I filter. The filters were designed to meet bandpass specifications and their magnitude and phase responses were analyzed. The filters were also compared in terms of their bit error rate (BER) performance under different signal conditions such as clean, interference, noise, and both interference and noise. The Chebyshev type I filter was found to have a higher BER under noise conditions compared to the other filters.
1) The document describes the design of a compensation filter for a Generalized Comb Filter (GCF) using a Maximally-Flat minimization technique.
2) The coefficients of the proposed compensation filter are obtained by solving two linear equations to minimize passband droop.
3) The compensation filter operates at a lower rate than the GCF and significantly reduces passband droop when cascaded with the GCF.
Echo Cancellation Algorithms using Adaptive Filters: A Comparative Studyidescitation
An adaptive filter is a filter that self-adjusts its transfer function according to an
optimization algorithm driven by an error signal. Adaptive filter finds its essence in
applications such as echo cancellation, noise cancellation, system identification and many
others. This paper briefly discusses LMS, NLMS and RLS adaptive filter algorithms for
echo cancellation. For the analysis, an acoustic echo canceller is built using LMS, NLMS
and RLS algorithms and the echo cancelled samples are studied using Spectrogram. The
analysis is further extended with its cross-correlation and ERLE (Echo Return Loss
Enhancement) results. Finally, this paper concludes with a better adaptive filter algorithm
for Echo cancellation. The implementation and analysis is done using MATLAB®,
SIMULINK® and SPECTROGRAM V5.0®.
Frequency domain filtering involves modifying the Fourier transform of an image by multiplying it with a filter function. Periodic noise appears as unusually high magnitudes in the spectral coefficients corresponding to the noise frequency. This noise can be reduced or removed in the frequency domain by correcting these coefficients using techniques like thresholding or median filtering in local neighborhoods. Filtering in blocks instead of the whole image can better handle non-uniform quasi-periodic noise.
Design of Low-Pass Digital Differentiators Based on B-splinesCSCJournals
This paper describes a new method for designing low-pass differentiators that could be widely suitable for low-frequency signals with different sampling rates. The method is based on the differential property of convolution and the derivatives of B-spline bias functions. The first order differentiator is just constructed by the first derivative of the B-spline of degree 5 or 4. A high (>2) order low-pass differentiator is constructed by cascading two low order differentiators, of which the coefficients are obtained from the nth derivative of a B-spline of degree n+2 expanded by factor a. In this paper, the properties of the proposed differentiators were presented. In addition, we gave the examples of designing the first to sixth order differentiators, and several simulations, including the effects of the factor a on the results and the anti-noise capability of the proposed differentiators. These properties analysis and simulations indicate that the proposed differentiator can be applied to a wide range of low-frequency signals, and the trade-off between noise- reduction and signal preservation can be made by selecting the maximum allowable value of a.
CORRELATION BASED FUNDAMENTAL FREQUENCY EXTRACTION METHOD IN NOISY SPEECH SIGNALijcseit
This paper proposed a correlation based method using the autocorrelation function and the YIN. The
autocorrelation function and also YIN is a popular measurement in estimating fundamental frequency in
time domain. The performance of these two methods, however, is effected due to the position of dominant
harmonics (usually the first formant) and the presence of spurious peaks introduced in noisy conditions.
The experimental results of computer simulations on female and male voices in different noises perform
that the gross pitch errors are lower in proposed method as compared to other related method in different
types of signal to noise ratio conditions.
The document discusses digital filter design. It begins by defining digital filters and their purposes, which include signal separation and distortion removal. It then covers the main types of digital filters - finite impulse response (FIR) and infinite impulse response (IIR) filters. FIR filters are implemented non-recursively without feedback, while IIR filters use recursion and feedback. The document outlines FIR filter design methods like windowing and discusses applications of digital filters such as noise suppression, frequency enhancement, and interference removal. In conclusion, digital filters can have linear phase response and are not affected by environmental factors like heat.
Compact Power Divider Integrated with Coupler and Microstrip Cavity Filter fo...TELKOMNIKA JOURNAL
This document summarizes the design and simulation of an integrated compact power divider module for an X-band surveillance radar system. The module integrates a 2-way power divider, directional coupler, and microstrip cavity bandpass filter into a single compact form to reduce losses from connectors. A 10-pole microstrip cavity filter was designed with a 432.9 MHz bandwidth. A Wilkinson power divider was designed with better than -28 dB return loss. A directional coupler was designed with -34.31 dB coupling and -26.74 dB isolation. Simulation results showed the integrated module had good performance with minimal losses and a compact size suitable for use in the radar system.
This document discusses the use of an adaptive decision feedback equalizer (ADFE) to mitigate pulse dispersion in optical communication channels. It begins by describing different sources of dispersion in optical fibers. Then it proposes using a fractional spaced decision feedback equalizer (FSDFE) integrated with activity detection guidance (ADG) and tap decoupling (TD) to improve performance. Simulation results show the FSDFE can estimate the channel impulse response and minimize differences between the input and output. Adding ADG and TD further improves convergence rate, detection of inactive taps, and asymptotic performance. The ADFE is an effective technique for equalization and mitigating dispersion in optical links.
Simulation Study of FIR Filter based on MATLABijsrd.com
First, the rapid design of FIR digital filter was completed by using the Signal Processing Toolbox FDA Tool, the case filter design of a composite signal by filtering, to prove that the content filter designed for filtering. MATLAB and Simulink programs of the filter were used to verify the performance of the filter in MATLAB. Experimental results show that the low-pass filter filters the high frequency component of input signals mixed. Comparison of two types of simulation, the latter method was more convenient quickly, and reduces the workload.
This document summarizes a digital signal processing project that involves resampling audio signals and modeling signals using autoregressive (AR) processes.
The resampling part involves downsampling two audio signals with correct and incorrect sampling rate conversions. Graphs and analysis show the resampled signals have lower quality and more distortion compared to the originals.
The AR modeling part estimates AR model coefficients from one of the signals using the Yule-Walker equations. A filter is designed to "whiten" the signal, removing noise. Graphs and audio comparison show the filtered signal has less noise but also some quality loss.
COMPARATIVE ANALYSIS OF SKIN COLOR BASED MODELS FOR FACE DETECTIONsipij
Human face detection plays an important role in many applications such as face recognition , human
computer interface, biometrics, area of energy conservation, video surveillance and face image database
management. The selection of accurate color model is the first need of the face detection. In this paper, a
study on the various color models for face detection i.e. RGB, YCbCr, HSV and CIELAB are included. This
paper compares different color models based on the detection rate of skin regions. The results shows that
YCbCr as compared to other color models yields the best output even in varying lightening conditions.
SPEECH ENHANCEMENT USING KERNEL AND NORMALIZED KERNEL AFFINE PROJECTION ALGOR...sipij
This document discusses speech enhancement using kernel and normalized kernel affine projection algorithms. It begins with an abstract that outlines using kernel adaptive filters in reproducing kernel Hilbert space to improve speech quality and intelligibility over conventional adaptive filters. It then provides background on adaptive filtering and its applications in noise cancellation. The document discusses challenges in speech enhancement like non-stationary noise and tradeoffs between noise removal and speech distortion. It describes using adaptive filters and kernel adaptive filters to enhance speech for applications like hearing aids and speech recognition.
This document contains 5 problems related to digital signal processing. Problem 1 involves designing a 25-tap finite impulse response (FIR) filter to approximate an ideal bandpass frequency response and plotting the filter's magnitude and phase response. Problem 2 repeats this for a bandstop filter. Problem 3 converts an analog filter to a digital infinite impulse response (IIR) filter using impulse invariance. Problem 4 does the same conversion using bilinear transformation. Problem 5 compares the two conversion methods and discusses their restrictions.
The document discusses digital filters and their design process. It explains that the design process involves four main steps: approximation, realization, studying arithmetic errors, and implementation.
For approximation, direct and indirect methods are used to generate a transfer function that satisfies the filter specifications. Realization generates a filter network from the transfer function. Studying arithmetic errors examines how quantization affects filter performance. Implementation realizes the filter in either software or hardware.
The document also outlines the basic building blocks of digital filters, including adders, multipliers, and delay elements. It introduces linear time-invariant digital filters and explains their input-output relationship using difference equations and the z-transform.
The document reports on a subjective comparison of 13 speech enhancement algorithms conducted by Dynastat, Inc. using the ITU-T P.835 methodology. The algorithms encompassed four classes: spectral subtractive, subspace, statistical-model based, and Wiener. A noisy speech corpus called NOIZEUS was developed with IEEE sentences corrupted by 8 noises at varying SNRs. For the subjective tests, enhanced speech from 20 sentences in 4 noises at 2 SNRs was evaluated based on signal distortion, noise distortion, and overall quality. The statistical-model based methods performed best overall, followed by a multi-band spectral subtraction method. Incorporating noise estimation did not significantly improve performance for some algorithms.
A new two stage FxNLMS algorithm based ANC system with secondary path modelling was proposed in
[15].Performance analysis of this system with real signals has been carried out using computer simulation.
Simulation studies showed that the system after trained with WGN can be successfully used for reducing
wide sense broad band noise.This paper also explores the intelligibility of speech signals in the quiet zone
created by the ANC system. The utterances of phonetically balanced Harvard sentences with different
SNRs are propagated through the quiet zone and the intelligibility of the resultant speech signal is
measured using MOS (Mean Opinion Score) test. Encouraging results are obtained which indicates that
the two stage FxNLMS algorithm based ANC system can find application in mobile phone communication.
This document discusses baseband shaping for data transmission. It introduces several digital modulation formats used for discrete PAM signals like unipolar, polar, bipolar and Manchester encoding. It then discusses factors that affect transmission like DC component, bandwidth, bit synchronization and error detection. It describes intersymbol interference and its causes like multipath propagation and bandlimited channels. It presents the baseband binary data transmission system model. Nyquist's criterion for zero ISI is defined. Practical solutions like raised cosine filters are discussed. The transmission bandwidth requirement is derived based on the rolloff factor. Finally, it describes what an eye diagram reveals about the system performance.
Analysis of Adaptive and Advanced Speckle Filters on SAR DataIOSRjournaljce
Synthetic Aperture RADAR(SAR) images get inherently affected by speckle noise which is multiplicative in nature. This noise affects the image spatial statistics and properties. Over the past several years, many SAR denoising algorithms have been developed to reduce speckle noise. Some of the standard speckle filters are Gamma MAP, Lee, Frost and Kuan filters. Further, these have also been modified to obtain better results after filtering, than their original counterparts. Apart from the standard speckle filters, advanced SAR filters like Block Matching 3 Dimensional (BM3D) are also present. In this paper several standard as well as advanced speckle filters have been analyzed and compared. For comparison, Quality Assessment has been performed where the filtered images are compared to each other using parameters like Radiometric Resolution and others. These parameters help to distinguish the performance of the filters on basis of signal strength, speckle reduction, mean preservation and edge and feature preservation. In the paper, radiometric resolution, speckle index and mean preservation index will be used to analyze among the performance of the filters.
I am Felix T. I am a Digital Signal Processing Assignment Expert at matlabassignmentexperts.com. I hold a Ph.D. in Matlab, University of Greenwich, UK. I have been helping students with their homework for the past 4 years. I solve assignments related to Digital Signal Processing.
Visit matlabassignmentexperts.com or email info@matlabassignmentexperts.com.
You can also call on +1 678 648 4277 for any assistance with Digital Signal Processing Assignments.
The document reports on a digital signal processing project to design and compare different types of FIR and IIR filters. FIR filters designed include a least squares filter and an equiripple filter. IIR filters designed include a Butterworth filter and a Chebyshev type I filter. The filters were designed to meet bandpass specifications and their magnitude and phase responses were analyzed. The filters were also compared in terms of their bit error rate (BER) performance under different signal conditions such as clean, interference, noise, and both interference and noise. The Chebyshev type I filter was found to have a higher BER under noise conditions compared to the other filters.
1) The document describes the design of a compensation filter for a Generalized Comb Filter (GCF) using a Maximally-Flat minimization technique.
2) The coefficients of the proposed compensation filter are obtained by solving two linear equations to minimize passband droop.
3) The compensation filter operates at a lower rate than the GCF and significantly reduces passband droop when cascaded with the GCF.
Echo Cancellation Algorithms using Adaptive Filters: A Comparative Studyidescitation
An adaptive filter is a filter that self-adjusts its transfer function according to an
optimization algorithm driven by an error signal. Adaptive filter finds its essence in
applications such as echo cancellation, noise cancellation, system identification and many
others. This paper briefly discusses LMS, NLMS and RLS adaptive filter algorithms for
echo cancellation. For the analysis, an acoustic echo canceller is built using LMS, NLMS
and RLS algorithms and the echo cancelled samples are studied using Spectrogram. The
analysis is further extended with its cross-correlation and ERLE (Echo Return Loss
Enhancement) results. Finally, this paper concludes with a better adaptive filter algorithm
for Echo cancellation. The implementation and analysis is done using MATLAB®,
SIMULINK® and SPECTROGRAM V5.0®.
Frequency domain filtering involves modifying the Fourier transform of an image by multiplying it with a filter function. Periodic noise appears as unusually high magnitudes in the spectral coefficients corresponding to the noise frequency. This noise can be reduced or removed in the frequency domain by correcting these coefficients using techniques like thresholding or median filtering in local neighborhoods. Filtering in blocks instead of the whole image can better handle non-uniform quasi-periodic noise.
Design of Low-Pass Digital Differentiators Based on B-splinesCSCJournals
This paper describes a new method for designing low-pass differentiators that could be widely suitable for low-frequency signals with different sampling rates. The method is based on the differential property of convolution and the derivatives of B-spline bias functions. The first order differentiator is just constructed by the first derivative of the B-spline of degree 5 or 4. A high (>2) order low-pass differentiator is constructed by cascading two low order differentiators, of which the coefficients are obtained from the nth derivative of a B-spline of degree n+2 expanded by factor a. In this paper, the properties of the proposed differentiators were presented. In addition, we gave the examples of designing the first to sixth order differentiators, and several simulations, including the effects of the factor a on the results and the anti-noise capability of the proposed differentiators. These properties analysis and simulations indicate that the proposed differentiator can be applied to a wide range of low-frequency signals, and the trade-off between noise- reduction and signal preservation can be made by selecting the maximum allowable value of a.
CORRELATION BASED FUNDAMENTAL FREQUENCY EXTRACTION METHOD IN NOISY SPEECH SIGNALijcseit
This paper proposed a correlation based method using the autocorrelation function and the YIN. The
autocorrelation function and also YIN is a popular measurement in estimating fundamental frequency in
time domain. The performance of these two methods, however, is effected due to the position of dominant
harmonics (usually the first formant) and the presence of spurious peaks introduced in noisy conditions.
The experimental results of computer simulations on female and male voices in different noises perform
that the gross pitch errors are lower in proposed method as compared to other related method in different
types of signal to noise ratio conditions.
The document discusses digital filter design. It begins by defining digital filters and their purposes, which include signal separation and distortion removal. It then covers the main types of digital filters - finite impulse response (FIR) and infinite impulse response (IIR) filters. FIR filters are implemented non-recursively without feedback, while IIR filters use recursion and feedback. The document outlines FIR filter design methods like windowing and discusses applications of digital filters such as noise suppression, frequency enhancement, and interference removal. In conclusion, digital filters can have linear phase response and are not affected by environmental factors like heat.
Compact Power Divider Integrated with Coupler and Microstrip Cavity Filter fo...TELKOMNIKA JOURNAL
This document summarizes the design and simulation of an integrated compact power divider module for an X-band surveillance radar system. The module integrates a 2-way power divider, directional coupler, and microstrip cavity bandpass filter into a single compact form to reduce losses from connectors. A 10-pole microstrip cavity filter was designed with a 432.9 MHz bandwidth. A Wilkinson power divider was designed with better than -28 dB return loss. A directional coupler was designed with -34.31 dB coupling and -26.74 dB isolation. Simulation results showed the integrated module had good performance with minimal losses and a compact size suitable for use in the radar system.
This document discusses the use of an adaptive decision feedback equalizer (ADFE) to mitigate pulse dispersion in optical communication channels. It begins by describing different sources of dispersion in optical fibers. Then it proposes using a fractional spaced decision feedback equalizer (FSDFE) integrated with activity detection guidance (ADG) and tap decoupling (TD) to improve performance. Simulation results show the FSDFE can estimate the channel impulse response and minimize differences between the input and output. Adding ADG and TD further improves convergence rate, detection of inactive taps, and asymptotic performance. The ADFE is an effective technique for equalization and mitigating dispersion in optical links.
Simulation Study of FIR Filter based on MATLABijsrd.com
First, the rapid design of FIR digital filter was completed by using the Signal Processing Toolbox FDA Tool, the case filter design of a composite signal by filtering, to prove that the content filter designed for filtering. MATLAB and Simulink programs of the filter were used to verify the performance of the filter in MATLAB. Experimental results show that the low-pass filter filters the high frequency component of input signals mixed. Comparison of two types of simulation, the latter method was more convenient quickly, and reduces the workload.
This document summarizes a digital signal processing project that involves resampling audio signals and modeling signals using autoregressive (AR) processes.
The resampling part involves downsampling two audio signals with correct and incorrect sampling rate conversions. Graphs and analysis show the resampled signals have lower quality and more distortion compared to the originals.
The AR modeling part estimates AR model coefficients from one of the signals using the Yule-Walker equations. A filter is designed to "whiten" the signal, removing noise. Graphs and audio comparison show the filtered signal has less noise but also some quality loss.
COMPARATIVE ANALYSIS OF SKIN COLOR BASED MODELS FOR FACE DETECTIONsipij
Human face detection plays an important role in many applications such as face recognition , human
computer interface, biometrics, area of energy conservation, video surveillance and face image database
management. The selection of accurate color model is the first need of the face detection. In this paper, a
study on the various color models for face detection i.e. RGB, YCbCr, HSV and CIELAB are included. This
paper compares different color models based on the detection rate of skin regions. The results shows that
YCbCr as compared to other color models yields the best output even in varying lightening conditions.
SPEECH ENHANCEMENT USING KERNEL AND NORMALIZED KERNEL AFFINE PROJECTION ALGOR...sipij
This document discusses speech enhancement using kernel and normalized kernel affine projection algorithms. It begins with an abstract that outlines using kernel adaptive filters in reproducing kernel Hilbert space to improve speech quality and intelligibility over conventional adaptive filters. It then provides background on adaptive filtering and its applications in noise cancellation. The document discusses challenges in speech enhancement like non-stationary noise and tradeoffs between noise removal and speech distortion. It describes using adaptive filters and kernel adaptive filters to enhance speech for applications like hearing aids and speech recognition.
A BRIEF OVERVIEW ON DIFFERENT ANIMAL DETECTION METHODSsipij
Researches based on animal detection plays a very vital role in many real life applications. Applications
which are very important are preventing animal vehicle collision on roads, preventing dangerous animal
intrusion in residential area, knowing locomotive behavioural of targeted animal and many more. There
are limited areas of research related to animal detection. In this paper we will discuss some of these areas
for detection of animals.
COMPRESSION BASED FACE RECOGNITION USING DWT AND SVMsipij
The biometric is used to identify a person effectively and employ in almost all applications of day to day
activities. In this paper, we propose compression based face recognition using Discrete Wavelet Transform
(DWT) and Support Vector Machine (SVM). The novel concept of converting many images of single person
into one image using averaging technique is introduced to reduce execution time and memory. The DWT is
applied on averaged face image to obtain approximation (LL) and detailed bands. The LL band coefficients
are given as input to SVM to obtain Support vectors (SV’s). The LL coefficients of DWT and SV’s are fused
based on arithmetic addition to extract final features. The Euclidean Distance (ED) is used to compare test
image features with database image features to compute performance parameters. It is observed that, the
proposed algorithm is better in terms of performance compared to existing algorithms.
Vocabulary length experiments for binary image classification using bov approachsipij
Bag-of-Visual-words (BoV) approach to image classification is popular among computer vision scientists.
The visual words come from the visual vocabulary which is constructed using the key points extracted from
the image database. Unlike the natural language, the length of such vocabulary for image classification is
task dependent. The visual words capture the local invariant features of the image. The region of image
over which a visual word is constrained forms the spatial content for the visual word. Spatial pyramid
representation of images is an approach to handle spatial information. In this paper, we study the role of
vocabulary lengths for the levels of a simple two level spatial pyramid to perform binary classifications.
Two binary classification problems namely to detect the presence of persons and cars are studied. Relevant
images from PASCAL dataset are being used for the learning activities involved in this work
n every image processing algorithm quality of ima
ge plays a very vital role because the output of th
e
algorithm depends on the quality of input image. He
nce, several techniques are used for image quality
enhancement and image restoration. Some of them are
common techniques applied to all the images
without having prior knowledge of noise and are cal
led image enhancement algorithms. Some of the image
processing algorithms use the prior knowledge of th
e type of noise present in the image and are referr
ed to
as image restoration techniques. Image restoration
techniques are also referred to as image de-noising
techniques. In such cases, identified inverse degra
dation functions are used to restore images. In thi
s
survey, we review several impulse noise removal tec
hniques reported in the literature and identify eff
icient
implementations. We analyse and compare the perform
ance of different reported impulse noise reduction
techniques with Restored Mean Absolute Error (RMAE)
under different noise conditions. Also, we identif
y
the most efficient impulse noise removing filters.
Marking the maximum and minimum performance of
filters helps in designing and comparing the new fi
lters which give better results than the existing f
ilters.
A HYBRID APPROACH BASED SEGMENTATION TECHNIQUE FOR BRAIN TUMOR IN MRI IMAGESsipij
Automatic image segmentation becomes very crucial for tumor detection in medical image processing.
Manual and semi automatic segmentation techniques require more time and knowledge. However these
drawbacks had overcome by automatic segmentation still there needs to develop more appropriate
techniques for medical image segmentation. Therefore, we proposed hybrid approach based image
segmentation using the combined features of region growing and threshold segmentation technique. It is
followed by pre-processing stage to provide an accurate brain tumor extraction by the help of Magnetic
Resonance Imaging (MRI). If the tumor has holes in it, the region growing segmentation algorithm can’t
reveal but the proposed hybrid segmentation technique can be achieved and the result as well improved.
Hence the result used to made assessment with the various performance measures as DICE, Jaccard
similarity, accuracy, sensitivity and specificity. These similarity measures have been extensively used for
evaluation with the ground truth of each processed image and its results are compared and analyzed.
A HYBRID APPROACH BASED SEGMENTATION TECHNIQUE FOR BRAIN TUMOR IN MRI IMAGESsipij
Automatic image segmentation becomes very crucial for tumor detection in medical image processing. Manual and semi automatic segmentation techniques require more time and knowledge. However these drawbacks had overcome by automatic segmentation still there needs to develop more appropriate techniques for medical image segmentation. Therefore, we proposed hybrid approach based image segmentation using the combined features of region growing and threshold segmentation technique. It is followed by pre-processing stage to provide an accurate brain tumor extraction by the help of Magnetic Resonance Imaging (MRI). If the tumor has holes in it, the region growing segmentation algorithm can’t reveal but the proposed hybrid segmentation technique can be achieved and the result as well improved. Hence the result used to made assessment with the various performance measures as DICE, Jaccard similarity, accuracy, sensitivity and specificity. These similarity measures have been extensively used for evaluation with the ground truth of each processed image and its results are compared and analyzed.
VISION BASED HAND GESTURE RECOGNITION USING FOURIER DESCRIPTOR FOR INDIAN SIG...sipij
Indian Sign Language (ISL) interpretation is the major research work going on to aid Indian deaf and dumb people. Considering the limitation of glove/sensor based approach, vision based approach was considered for ISL interpretation system. Among different human modalities, hand is the primarily used modality to any sign language interpretation system so, hand gesture was used for recognition of manual
alphabets and numbers. ISL consists of manual alphabets, numbers as well as large set of vocabulary with grammar. In this paper, methodology for recognition of static ISL manual alphabets, number and static symbols is given. ISL alphabet consists of single handed and two handed sign. Fourier descriptor as a feature extraction method was chosen due the property of invariant to rotation, scale and translation. True
positive rate was achieved 94.15% using nearest neighbourhood classifier with Euclidean distance where
sample data were considered with different illumination changes, different skin color and varying distance
from camera to signer position.
BRAIN PORTION EXTRACTION USING HYBRID CONTOUR TECHNIQUE USING SETS FOR T1 WEI...sipij
Brain portion extraction from magnetic resonance image (MRI) of human head scan is an important process in medical image analysis. In this paper, we propose a computationally simple and a robust brain segmentation method. This method is based on forming a contour using the intensity values that satisfy a set property and detect the boundary of the brain. After detecting the brain boundary the brain portion is segmented. Experiments were conducted by applying the method on 3 volumes of T1 MRI data set collected
from Internet Brain Segmentation Repository(IBSR) and compared the results with that of the popular skull stripping method Brain Extraction Tool (BET). The experimental results show that the proposed algorithm gives better results than that of BET.
Efficient Reversible Data Hiding Algorithms Based on Dual Predictionsipij
In this paper, a new reversible data hiding (RDH) algorithm that is based on the concept of shifting of
prediction error histograms is proposed. The algorithm extends the efficient modification of prediction
errors (MPE) algorithm by incorporating two predictors and using one prediction error value for data
embedding. The motivation behind using two predictors is driven by the fact that predictors have different
prediction accuracy which is directly related to the embedding capacity and quality of the stego image. The
key feature of the proposed algorithm lies in using two predictors without the need to communicate
additional overhead with the stego image. Basically, the identification of the predictor that is used during
embedding is done through a set of rules. The proposed algorithm is further extended to use two and three
bins in the prediction errors histogram in order to increase the embedding capacity. Performance
evaluation of the proposed algorithm and its extensions showed the advantage of using two predictors in
boosting the embedding capacity while providing competitive quality for the stego image.
Semi blind rgb color image watermarking using dct and two level svdsipij
This paper presents semi blind RGB color image wate
rmarking using DCT and two-level SVD. First, RGB
image is divided into red, green, and blue channels
. The blue component is divided into blocks accordi
ng
to the watermark size. Second, DCT is applied to ea
ch block to form a new block in the transform domai
n.
DC component is retrieved and assembled from each b
lock to form a new matrix of 128x128 pixels. SVD is
applied to the resultant matrix to obtain matrices,
U, S and V. The watermark is embedded into the S
matrix. The watermark can be extracted without orig
inal host image, however, matrices U1, S and V1 are
required. Experimental results indicate that the pr
oposed algorithm can satisfy imperceptibility and i
t is
more robust against common types of attacks such as
filtering, adding noise, geometric and compression
attacks.
Computer apparition plays the most important role in human perception, which is limited to only the visual band of the electromagnetic spectrum. The need for Radar imaging systems, to recover some sources that
are not within human visual band, is raised. This paper present new algorithm for Synthetic Aperture Radar (SAR) images segmentation based on thresholding technique. Entropy based image thresholding has
received sustainable interest in recent years. It is an important concept in the area of image processing.
Pal (1996) proposed a cross entropy thresholding method based on Gaussian distribution for bi-modal images. Our method is derived from Pal method that segment images using cross entropy thresholding based on Gamma distribution and can handle bi-modal and multimodal images. Our method is tested using
Synthetic Aperture Radar (SAR) images and it gave good results for bi-modal and multimodal images. The
results obtained are encouraging.
RGBEXCEL: AN RGB IMAGE DATA EXTRACTOR AND EXPORTER FOR EXCEL PROCESSINGsipij
The objective of this paper was to develop a means of rapidly obtaining RGB image data, as part of an
effort to develop a low-cost method of image processing and analysis based on Microsoft Excel. A simple
standalone GUI (graphical user interface) software application called RGBExcel was developed to extract
RGB image data from any colour image files of any format. For a given image file, the output from the
software is an Excel file with the data from the R (red), G (green), and B (blue) bands of the image
contained in different sheets. The raw data and any enhancements can be visualized by using the surface
chart type in combination with other features. Since Excel can plot a maximum dimension of 255 by 255
pixels, larger images are downscaled to have a maximum dimension of 255 pixels. Results from testing the
application are discussed in the paper.
BRAIN PORTION EXTRACTION USING HYBRID CONTOUR TECHNIQUE USING SETS FOR T1 WEI...sipij
Brain portion extraction from magnetic resonance image (MRI) of human head scan is an important
process in medical image analysis. In this paper, we propose a computationally simple and a robust brain
segmentation method. This method is based on forming a contour using the intensity values that satisfy a
set property and detect the boundary of the brain. After detecting the brain boundary the brain portion is
segmented. Experiments were conducted by applying the method on 3 volumes of T1 MRI data set collected
from Internet Brain Segmentation Repository(IBSR) and compared the results with that of the popular
skull stripping method Brain Extraction Tool (BET). The experimental results show that the proposed
algorithm gives better results than that of BET.
This document summarizes a research paper that proposes a conditional entrench spatial domain steganography technique (CESS). CESS embeds secret information in the least significant bit and most significant bit of cover images based on predefined conditions to increase security and capacity. It decomposes cover images into 8x8 blocks. The first block embeds upper and lower bound values used for payload retrieval. Each subsequent 8x8 block embeds the payload in LSBs and MSBs of pixels based on the block's mean of median values and difference between consecutive pixels. The technique is evaluated based on capacity, security and PSNR compared to existing methods.
Symbolic representation and recognition of gait an approach based on lbp of ...sipij
Gait is one of the biometric techniques used to identify an individual from a distance by his/her walking
style. Gait can be recognized by studying the static and dynamic part variations of individual body contour
during walk. In this paper, an interval value based representation and recognition of gait using local
binary pattern (LBP) of split gait energy images is proposed. The gait energy image (GEI) of a subject is
split into four equal regions. LBP technique is applied to each region to extract features and the extracted
features are well organized. The proposed representation technique is capable of capturing variations in
gait due to change in cloth, carrying a bag and different instances of normal walking conditions more
effectively. Experiments are conducted on the standard and considerably large database (CASIA database
B) and newly created University of Mysore (UOM) gait dataset to study the efficacy of the proposed gait
recognition system. The proposed system being robust to handle variations has shown significant
improvement in recognition rate.
This document summarizes research on the effect of face tampering on face recognition. It discusses four categories of face recognition algorithms (PCA, iSVM, LBP, SIFT) and their accuracy rates under different tampering protocols using a novel tampered face image database. The conclusion is that it is unpredictable which algorithm will perform best for tampered face recognition. Motion analysis, texture analysis, and liveness detection techniques in prior research aimed to detect spoofing but may not distinguish tampered from real faces.
DESIGN REALIZATION AND PERFORMANCE EVALUATION OF AN ACOUSTIC ECHO CANCELLATIO...sipij
Nowadays, in the field of communications, AEC (acoustic echo cancellation) is truly essential with respect
to the quality of multimedia transmission. In this paper, we designed and developed an efficient AEC based
on adaptive filters to improve quality of service in telecommunications against the phenomena of acoustic
echo, which is indeed a problem in hands-free communications.The main advantage of the proposed algorithm is its capacity of tracking non-stationary signals such as acoustic echo. In this work the acoustic echo cancellation (AEC) is modeled using a digital signal
processing technique especially Simulink Blocksets. The algorithm’s code is generated in Matlab Simulink
programming environment. At simulation level, results of simulink implementation prove that module
behavior is realistic when it comes to cancellation of echo in hands free communication using adaptive algorithm.Results obtained with our algorithm in terms of ERLE criteria are confronted to IUT-T recommendation
G.168.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
This document summarizes a research paper on echo cancellation using adaptive combination of normalized subband adaptive filters (NSAFs). The paper proposes using adaptive combination of NSAFs to achieve both fast convergence and low steady-state mean squared error. The input signal is divided into subbands, and NSAFs are adapted independently in each subband. Adaptive combination is then performed by adapting a mixing parameter that controls the combination of subband outputs. Experimental results show the proposed method achieves improved performance over conventional NSAF methods using fewer adaptive filters.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
This document discusses echo cancellation using adaptive combination of normalized subband adaptive filters (NSAFs). It presents the following:
1. Fullband adaptive filters can have slow convergence due to correlated speech input and long echo path impulse responses. Subband adaptive filters (SAFs) address this by using individual adaptive filters in spectral subbands.
2. Adaptive combination of SAFs provides a way to achieve both fast convergence and small steady-state error. It independently adapts filters with different step sizes, then combines them using a mixing parameter adapted by stochastic gradient descent.
3. The proposed method adaptively combines NSAFs in subbands. It uses a large step size filter for fast convergence and a
In many situations, the Electrocardiogram (ECG) is
recorded during ambulatory or strenuous conditions such that the
signal is corrupted by different types of noise, sometimes
originating from another physiological process of the body. Hence,
noise removal is an important aspect of signal processing. Here five
different filters i.e. median, Low Pass Butter worth, FIR, Weighted
Moving Average and Stationary Wavelet Transform (SWT) with
their filtering effect on noisy ECG are presented. Comparative
analyses among these filtering techniques are described and
statically results are evaluated.
Analysis the results_of_acoustic_echo_cancellation_for_speech_processing_usin...Venkata Sudhir Vedurla
This document presents an analysis of acoustic echo cancellation for speech processing using the LMS adaptive filtering algorithm. It begins with an abstract that outlines the challenges of conventional echo cancellation techniques and the need for a computationally efficient, rapidly converging algorithm. It then provides background on acoustic echo, the principles of echo cancellation, discrete time signals, speech signals, and an overview of the LMS adaptive filtering algorithm and its application to echo cancellation. The document analyzes the performance of the LMS algorithm for echo cancellation by examining how the step size parameter affects convergence and steady state error. It concludes that the LMS algorithm is well-suited for echo cancellation due to its computational simplicity, though the step size must be carefully selected for optimal performance
The document discusses digital filters and their design. It begins with an introduction to filters and their uses in signal processing applications. It then covers linear time-invariant filters and their transfer functions. It discusses the differences between non-recursive (FIR) and recursive (IIR) filters. The document presents various filter structures for implementation, including direct form I and direct form II structures. It also discusses designing FIR and IIR filters as well as issues in their implementation.
Impedance Cardiography Filtering Using Non-Negative Least-Mean-Square Algorithmijcisjournal
In general using several signal acquisition methods are applied to get cardio-impedance signal to analyse
the cardiac output. The analysis completely based on frequency information obtained after applying
frequency selection filters and frequency shaping filters. Here proposing a constructive approach involves
a developed Non-Negative LMS (NNLMS) followed by filtering techniques to measure and overcome the
limitations of commonly used approaches. The proposed technique performance is analysed by considering
different types of noise environments like fundamental one white noise and also sum of sinusoidal noise.
The simulation results are useful to measure the performance and accuracy under different noise
environments also a comparative analysis is done with the proposed work with existing methods under
different performance metrics by the help of quantitative analysis of algorithms. Simulation results are
found to be satisfactory in the analysis of cardiac output.
This document discusses using a triangular window-based FIR digital filter to remove powerline interference from ECG signals. ECG signals are often corrupted by noise such as powerline interference that can interfere with diagnosis. The authors designed a triangular window FIR filter with a modified triangular window function to filter ECG signals. They tested the filter on simulated noisy ECG data and found it successfully removed the 50Hz powerline interference, reducing the noise power. Analysis of the filter's magnitude, phase, and frequency responses indicated it provides stable and linear phase filtering required for ECG signal processing. The triangular window FIR filter is an effective technique for denoising ECG signals by removing powerline interference.
This document discusses moving average filters and their properties. It begins by defining the moving average filter equation and explaining that it operates by averaging neighboring points in the input signal. While simple, the moving average filter is optimal for reducing random noise while maintaining a sharp step response. It has poor performance in the frequency domain, however, with a slow roll-off and inability to separate frequencies. Relatives like multiple-pass moving average filters have slightly better frequency response at the cost of increased computation. The document provides examples and equations to illustrate the properties of moving average filters.
ECG Signal Denoising using Digital Filter and Adaptive FilterIRJET Journal
1. The document discusses methods for denoising electrocardiogram (ECG) signals, including digital filters and adaptive filters.
2. It evaluates the performance of Savitzky-Golay filters, band pass filters, and adaptive noise cancellation techniques for removing noise from ECG signals and improving the signal-to-noise ratio.
3. The key filters discussed are Savitzky-Golay filters, Tompkins filters, Butterworth band pass filters, and least mean square adaptive filters, analyzing their ability to reduce noise like powerline interference, baseline drift, and motion artifacts from ECG data.
Evaluation of channel estimation combined with ICI self-cancellation scheme i...ijcsse
Orthogonal Frequency Division Multiplexing (OFDM) is a modulation scheme, which is used in several wireless systems for transferring data at high rate. The multi path fading channel and the frequency offset between the transmitted and received carrier frequencies introduce ICI (Inter Carrier Interference). ICI effects the OFDM symbols and degrades the system performance. This paper proposes a solution: combine channel estimation and ICI self-cancellation to combat against ICI in doubly selective fading channel. The simulation results show the effect of this solution
Intersymbol interference caused by multipath in band limited frequency selective time dispersive channels distorts the transmitted signal, causing bit error at receiver. ISI is the major obstacle to high speed data transmission over wireless channels. Channel estimation is a technique used to combat the intersymbol interference. The objective of this paper is to improve channel estimation accuracy in MIMO-OFDM system by using modified variable step size leaky Least Mean Square (MVSSLLMS) algorithm proposed for MIMO OFDM System. So we are going to analyze Bit Error Rate for different signal to noise ratio, also compare the proposed scheme with standard LMS channel estimation method.
This document describes a study that introduces a Modified Error Data Normalized Step Size (MEDNSS) algorithm for an adaptive noise canceller. The MEDNSS algorithm uses a time-varying step size that depends on normalization of both the error and data vectors. The performance of the MEDNSS algorithm is analyzed through computer simulation and compared to the Error Data Normalized Step Size algorithm in stationary and non-stationary environments with different noise power levels. Simulation results show the MEDNSS algorithm significantly improves minimizing signal distortion, excess mean square error, and misadjustment factor compared to the EDNSS algorithm.
This document discusses the implementation of different types of transmultiplexer (TMUX) structures for filter bank multicarrier systems. It describes maximally decimated, non-maximally decimated, and partial TMUX structures. For each structure, the analysis and synthesis filter banks are designed such that the filters are complex modulated versions of a prototype filter. Frequency sampling is used to design the prototype filter. Simulation results show perfect reconstruction is achieved for the maximally decimated TMUX, while non-maximally decimated TMUX achieves nearly perfect reconstruction. The partial TMUX relaxes the perfect reconstruction condition to allow for small distortions.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A review of literature shows that there is a variety of adaptive filters. In this research study, we propose a new type of an adaptive filter that increases the diversification used to compensate the chan-nel distortion effect in the MC-CDMA transmission. First, we show the expressions of the filter’s impulse responses in the case of a perfect channel. The adaptive filter has been simulated and experienced by blind equalization for different cases of Gaussian white noise in the case of an MC-CDMA transmission with orthogonal frequency baseband for a mobile radio downlink channel Bran A. The simulation results show the performance of the proposed identification and blind equalization algorithm for MC-CDMA transmission chain using IFFT.
A New Method for a Nonlinear Acoustic Echo Cancellation SystemIRJET Journal
This document proposes a new method for acoustic echo cancellation in nonlinear systems using an artificial neural network combined with a Laguerre filter model. It begins by discussing the challenges of acoustic echo cancellation and existing linear echo cancellation methods. It then introduces using an artificial neural network with a nonlinear activation function and a Laguerre filter model to better handle nonlinear echo paths. Simulation results are presented showing the effectiveness of the proposed neural network and Laguerre filter method at cancelling echo signals in nonlinear environments.
The document discusses various topics related to pulse modulation systems including sampling, Pulse Code Modulation (PCM), and quantization noise. Some key points:
1. A signal can be recovered from its samples by passing it through an ideal low-pass filter with the appropriate bandwidth to remove aliases introduced by sampling.
2. In PCM, the maximum quantization error occurs when the analog voltage being converted is at the midpoint between two quantization levels, and equals half the voltage interval size.
3. Increasing the number of bits per sample in a PCM system increases the signal-to-quantization noise ratio by 6 dB, as each additional bit provides an increase of 6 dB.
Channel Equalization of WCDMA Downlink System Using Finite Length MMSE-DFEIOSR Journals
Abstract: The performance of WCDMA system deteriorates in the presence of multipath fading environment. Fading destroys the orthogonality and is responsible for multiple access interference (MAI). Though conventional rake receiver provides reasonable performance in the WCDMA downlink system due to path diversity, but it does not restores the orthogonality. Linear equalizer restores orthogonality and suppresses MAI, but it is not efficient, since its performance depends on the spectral characteristics of the channel. To overcome this, Minimum Mean Square Error- Decision Feedback Equalizer (MMSE-DFE) with a linear, anticausal feedforward filter, causal feedback filter and simple detector is proposed in this paper. The filter taps of finite length DFE is derived using the cholesky factorization theory, capable of suppressing noise, Intersymbol Interference (ISI) and MAI. This paper describes the WCDMA downlink system using finite length MMSE-DFE and takes into consideration the effects of interference which includes additive white gaussian noise, multipath fading, ISI and MAI. Furthermore, the performance is compared with conventional rake receiver and MMSE and the simulation results are shown. Keywords – MMSE, MMSE-DFE, rake receiver, WCDMA
Channel Equalization of WCDMA Downlink System Using Finite Length MMSE-DFEIOSR Journals
The performance of WCDMA system deteriorates in the presence of multipath fading environment.
Fading destroys the orthogonality and is responsible for multiple access interference (MAI). Though
conventional rake receiver provides reasonable performance in the WCDMA downlink system due to path
diversity, but it does not restores the orthogonality. Linear equalizer restores orthogonality and suppresses
MAI, but it is not efficient, since its performance depends on the spectral characteristics of the channel. To
overcome this, Minimum Mean Square Error- Decision Feedback Equalizer (MMSE-DFE) with a linear,
anticausal feedforward filter, causal feedback filter and simple detector is proposed in this paper. The filter taps
of finite length DFE is derived using the cholesky factorization theory, capable of suppressing noise,
Intersymbol Interference (ISI) and MAI. This paper describes the WCDMA downlink system using finite length
MMSE-DFE and takes into consideration the effects of interference which includes additive white gaussian
noise, multipath fading, ISI and MAI. Furthermore, the performance is compared with conventional rake
receiver and MMSE and the simulation results are shown.
Similar to D ESIGN A ND I MPLEMENTATION OF D IGITAL F ILTER B ANK T O R EDUCE N OISE A ND R ECONSTRUCT T HE I NPUT S IGNALS (20)
AI for Legal Research with applications, toolsmahaffeycheryld
AI applications in legal research include rapid document analysis, case law review, and statute interpretation. AI-powered tools can sift through vast legal databases to find relevant precedents and citations, enhancing research accuracy and speed. They assist in legal writing by drafting and proofreading documents. Predictive analytics help foresee case outcomes based on historical data, aiding in strategic decision-making. AI also automates routine tasks like contract review and due diligence, freeing up lawyers to focus on complex legal issues. These applications make legal research more efficient, cost-effective, and accessible.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
VARIABLE FREQUENCY DRIVE. VFDs are widely used in industrial applications for...PIMR BHOPAL
Variable frequency drive .A Variable Frequency Drive (VFD) is an electronic device used to control the speed and torque of an electric motor by varying the frequency and voltage of its power supply. VFDs are widely used in industrial applications for motor control, providing significant energy savings and precise motor operation.
Design and optimization of ion propulsion dronebjmsejournal
Electric propulsion technology is widely used in many kinds of vehicles in recent years, and aircrafts are no exception. Technically, UAVs are electrically propelled but tend to produce a significant amount of noise and vibrations. Ion propulsion technology for drones is a potential solution to this problem. Ion propulsion technology is proven to be feasible in the earth’s atmosphere. The study presented in this article shows the design of EHD thrusters and power supply for ion propulsion drones along with performance optimization of high-voltage power supply for endurance in earth’s atmosphere.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Rainfall intensity duration frequency curve statistical analysis and modeling...bijceesjournal
Using data from 41 years in Patna’ India’ the study’s goal is to analyze the trends of how often it rains on a weekly, seasonal, and annual basis (1981−2020). First, utilizing the intensity-duration-frequency (IDF) curve and the relationship by statistically analyzing rainfall’ the historical rainfall data set for Patna’ India’ during a 41 year period (1981−2020), was evaluated for its quality. Changes in the hydrologic cycle as a result of increased greenhouse gas emissions are expected to induce variations in the intensity, length, and frequency of precipitation events. One strategy to lessen vulnerability is to quantify probable changes and adapt to them. Techniques such as log-normal, normal, and Gumbel are used (EV-I). Distributions were created with durations of 1, 2, 3, 6, and 24 h and return times of 2, 5, 10, 25, and 100 years. There were also mathematical correlations discovered between rainfall and recurrence interval.
Findings: Based on findings, the Gumbel approach produced the highest intensity values, whereas the other approaches produced values that were close to each other. The data indicates that 461.9 mm of rain fell during the monsoon season’s 301st week. However, it was found that the 29th week had the greatest average rainfall, 92.6 mm. With 952.6 mm on average, the monsoon season saw the highest rainfall. Calculations revealed that the yearly rainfall averaged 1171.1 mm. Using Weibull’s method, the study was subsequently expanded to examine rainfall distribution at different recurrence intervals of 2, 5, 10, and 25 years. Rainfall and recurrence interval mathematical correlations were also developed. Further regression analysis revealed that short wave irrigation, wind direction, wind speed, pressure, relative humidity, and temperature all had a substantial influence on rainfall.
Originality and value: The results of the rainfall IDF curves can provide useful information to policymakers in making appropriate decisions in managing and minimizing floods in the study area.
Gas agency management system project report.pdfKamal Acharya
The project entitled "Gas Agency" is done to make the manual process easier by making it a computerized system for billing and maintaining stock. The Gas Agencies get the order request through phone calls or by personal from their customers and deliver the gas cylinders to their address based on their demand and previous delivery date. This process is made computerized and the customer's name, address and stock details are stored in a database. Based on this the billing for a customer is made simple and easier, since a customer order for gas can be accepted only after completing a certain period from the previous delivery. This can be calculated and billed easily through this. There are two types of delivery like domestic purpose use delivery and commercial purpose use delivery. The bill rate and capacity differs for both. This can be easily maintained and charged accordingly.
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Energy efficiency has been important since the latter part of the last century. The main object of this survey is to determine the energy efficiency knowledge among consumers. Two separate districts in Bangladesh are selected to conduct the survey on households and showrooms about the energy and seller also. The survey uses the data to find some regression equations from which it is easy to predict energy efficiency knowledge. The data is analyzed and calculated based on five important criteria. The initial target was to find some factors that help predict a person's energy efficiency knowledge. From the survey, it is found that the energy efficiency awareness among the people of our country is very low. Relationships between household energy use behaviors are estimated using a unique dataset of about 40 households and 20 showrooms in Bangladesh's Chapainawabganj and Bagerhat districts. Knowledge of energy consumption and energy efficiency technology options is found to be associated with household use of energy conservation practices. Household characteristics also influence household energy use behavior. Younger household cohorts are more likely to adopt energy-efficient technologies and energy conservation practices and place primary importance on energy saving for environmental reasons. Education also influences attitudes toward energy conservation in Bangladesh. Low-education households indicate they primarily save electricity for the environment while high-education households indicate they are motivated by environmental concerns.
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1. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
DOI : 10.5121/sipij.2015.6202 15
DESIGN AND IMPLEMENTATION OF DIGITAL
FILTER BANK TO REDUCE NOISE AND
RECONSTRUCT THE INPUT SIGNALS
Kawser Ahammed1
, Md. Ershadullah2
, Md. Rakebul Islam Heru3
, Saiful Islam4
and Dr. Z. M. Parvez Sazzad5
1,2,3,4
Department of Electrical & Electronic Engineering (Former Applied Physics,
Electronics & Communication Engineering),
University of Dhaka, Dhaka, Bangladesh
5
Professor, Department of Electrical & Electronic Engineering,
University of Dhaka, Dhaka, Bangladesh
ABSTRACT
The main theme of this paper is to reduce noise from the noisy composite signal and reconstruct the input
signals from the composite signal by designing FIR digital filter bank. In this work, three sinusoidal signals
of different frequencies and amplitudes are combined to get composite signal and a low frequency noise
signal is added with the composite signal to get noisy composite signal. Finally noisy composite signal is
filtered by using FIR digital filter bank to reduce noise and reconstruct the input signals.
KEYWORDS
Digital Filter Bank, Noise, LMS Filter, LMS Algorithm, Composite Signal
1. INTRODUCTION
Over the past two decades, the research on efficient design of filter banks has received
considerable attention in numerous fields such as speech coding, scrambling, image processing
etc. [1-2]. At the same time design of filter banks has received attention on noise reduction. So
noises in any digital signals significantly hamper the actual performance of signals at the desired
output [3-4]. So filter banks are required to reduce these noises. A filter bank is nothing but a
group of parallel low pass, band pass and high pass filters [5] that separate the input signal into
multiple components, each one carrying a single frequency subband of the original signal [6]. The
process of decomposition performed by the filter bank is called analysis. The reconstruction
process is called synthesis, meaning reconstitution of a complete signal resulting from the
filtering process [7]. Filter banks are generally classified as two types, analysis filter banks and
synthesis filter banks [8]. An analysis filter bank comprises of filters, with system transfer
functions {Hk(z)}, where k= 0, 1, …. , M-1; arranged in a parallel bank as shown in Figure 1. On
the contrary, a synthesis filter bank comprises of a set of filters with system transfer functions
{Gk(z)} , where k= 0, 1, … , M-1; arranged as shown in Figure 2, with corresponding inputs
{yk(m)}.The outputs of the filters are summed to form the synthesized signal ݔ(݊). The blocks
with arrows pointing downwards in Figure1 indicate down sampling by factor N, and the blocks
with arrows pointing upwards in Figure 2 indicate up sampling by N.
2. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
16
Analysis Filter Bank Subband
signals
ݕ(݉)
ݕଵ(݉)
x(n) . .
. .
. .
ݕெିଵ(݉)
Figure 1. Analysis filter bank, adapted from Ref. [1]
Sub sampling by N means that only every N-th sample is taken. This operation serves to reduce
or eliminate redundancies in the M subband signals. Up sampling by N means the insertion of N-
1 consecutive zeros between the samples. This allows us to recover the original sampling rate.
There are many applications of filter banks such as graphic equalizer, signal compression, bank of
receiver, noise reduce etc.
Subband Synthesis Filter Bank
signals
ݕ(݉)
ݕଵ(݉) ݔ(݊)
. .
. .
. .
ݕெିଵ(݉)
Figure 2. Synthesis filter bank, adapted from Ref. [1]
2. EXAMPLE OF A FILTER BANK
In this section, a two channel filter bank adapted from ref. [9] has been described. Figure 3 shows
such kind of two channel filter bank. It is convenient to analyse the filter bank in the Z-domain.
Therefore, by using Z-transform the expressions for the various intermediate signals in figure 3
are given by
ܴ(ݖ) = ܪ(ݖ)ܷ(ݖ) (1)
ܵ(ݖ) =
1
2
൜ܴ ൬ݖ
ଵ
ଶ൰ + ܴ ൬−ݖ
ଵ
ଶ൰ൠ (2)
ܪ()ݖ N ↓
ܪଵ()ݖ
ܪெିଵ()ݖ
N ↓
N ↓
ܩ()ݖN ↑
ܩଵ()ݖ
ܩெିଵ()ݖ
N ↑
N ↑
3. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
17
ܹ(ݖ) = ܵ(ݖଶ) (3)
for l=0,1. After performing some algebra, the following equation is obtained
ܹ()ݖ =
1
2
ሼܴ()ݖ + ܴ(−})ݖ =
1
2
ሼܪ()ݖ ܷ()ݖ + ܪ(−)ݖ ܷ(−ܼ) } (4)
Now the reconstructed output of the filter bank is attained by
ܸ(ݖ) = ܩ(ݖ)ܹ(ݖ) + ܩଵ(ݖ) ܹଵ(ݖ) (5)
Substituting equation (4) in equation (5), the output of the filter bank is obtained by
ܸ()ݖ =
1
2
ሼܪ(ܩ)ݖ()ݖ + ܪଵ(ܩ)ݖଵ(})ݖ ܷ()ݖ +
1
2
ሼܪ(−ܩ)ݖ()ݖ
+ ܪଵ(−ݖ)ܩଵ(ݖ)} ܷ(−)ݖ (6)
The first term in the above equation describes the transmission of the signal U (z) through
the system, while the second term describes the aliasing component at the output. The
above equation can be compactly represented as
ܸ(ݖ) = ܦ(ݖ)ܷ(ݖ) + ܤ(ݖ)ܷ(−ݖ) (7)
Where ܦ(ݖ) =
ଵ
ଶ
ሼܪ(ݖ)ܩ(ݖ) + ܪଵ(ݖ)ܩଵ(ݖ)}ܷ(ݖ) (8)
is called the distortion transfer function, and
)ݖ(ܤ =
1
2
ሼܪ(−ܩ)ݖ(ݖ) + ܪଵ(−ݖ)ܩଵ(ݖ)}ܷ(−)ݖ (9)
r0 (n) s0 (n) w0 (n)
u(n) v(n)
r1 (n) s1 (n) w1 (n)
Figure 3. Two channel filter bank, adapted from Ref. [1]
3. METHODOLOGY
At the first step, amplitude, frequency and sample time of three sinusoidal signals, denoted by A1,
B1 and C1, are fixed to form composite signal and a random source is considered to get random
signal. The random source acts as a noise source. The block parameters of three sinusoidal signals
are shown in Figure 4.
2↓ܪ()ݖ 2↑
2↑2↓ܪଵ()ݖ ܩଵ()ݖ
ܩ()ݖ
4. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
18
Figure 4. Block parameters of three sinusoidal signals A1, B1 and C1
At the second step, an FIR digital filter is designed by using MATLAB to allow a low frequency
noise signal obtained from random source to pass through it. The magnitude response of this filter
is shown in Figure 5.
5. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
19
Figure 5. Magnitude response of FIR digital filter
At the third step, three FIR digital filters are designed to reconstruct the three sinusoidal signals
from the composite signal. These three FIR digital filters are designed by using MATLAB. The
magnitude responses of these three filters are shown in Figure 6, Figure 7 and Figure 8. Among
three filter designs, the filter design1 is designed to reconstruct the sinusoidal signal A1.The filter
design2 is designed to reconstruct the sinusoidal signal B2. The filter design3 is designed to
reconstruct the sinusoidal signal C1. All three FIR digital filters form the filter combination
block. To design these three FIR digital filters, initially the filter response type is fixed (Low pass
response). Then the design method is fixed (FIR window) and the window type is fixed
(Hamming window). Finally the cut off frequency, the filter order and sampling frequency are
fixed to get the desired magnitude response. From Figure 6, Figure 7 and Figure 8, it is seen that
the attenuation at cut off frequencies is fixed at 6dB (half the pass band gain) and the vertical axis
represents the magnitude (dB) and the horizontal axis represents the normalized frequency (×π
radian/sample).
Figure 6. Magnitude response of digital filter design1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
-160
-140
-120
-100
-80
-60
-40
-20
0
20
Normalized Frequency (××××ππππ rad/sample)
Magnitude(dB)
Magnitude Response (dB)
Lowpass FIR Window
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
-70
-60
-50
-40
-30
-20
-10
0
Normalized Frequency (××××ππππ rad/sample)
Magnitude(dB)
Magnitude Response Estimate
Lowpass FIR Window
6. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
20
Figure 7. Magnitude response of digital filter design2
Figure 8. Magnitude response of digital filter design3
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
-60
-50
-40
-30
-20
-10
0
Normalized Frequency (××××ππππ rad/sample)
Magnitude(dB)
Magnitude Response (dB)
Lowpass FIR Window
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
-60
-50
-40
-30
-20
-10
0
Normalized Frequency (××××ππππ rad/sample)
Magnitude(dB)
Magnitude Response (dB)
Lowpass FIR Window
7. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
21
Figure 9. Simulation block diagram to reduce noise and reconstruct the input signals
3.1. LMS FILTER
The LMS Filter block, shown in Figure 9, can implement an adaptive FIR filter using five
different algorithms. The block estimates the filter weights, or coefficients, needed to minimize
the error between the output signal and the desired signal [10]. Connect the signal which I want to
filter to the Input port. This input signal can be a sample-based scalar or a single-channel frame-
based signal. Connect the desired signal to the desired port. The desired signal must have the
same data type, frame status, complexity, and dimensions as the input signal. The Output port
outputs the filtered input signal, which is the estimate of the desired signal. The output of the
Output port has the same frame status as the input signal. The Error port outputs the result of
subtracting the output signal from the desired signal [11]. An important general form for adaptive
filters is the Least Mean Square (LMS) filter. Consider the N-th order FIR filter,
yn=h(1)xn-1+h(2)xn-2+……..+h(n)xn-N (10)
the filter error is,
e (n)=xn - yn (11)
The LMS filter adjusts the values of the coefficients, h, proportional to the error, e
hi(n) = hi-1(n)+2µxn-i en (12)
where µ is a learning factor which controls how strongly the error is weighted. This equation is
the consequence of the requirement to minimize mean square value of , e ,hence the name of the
filter [12].
8. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
22
3.2 LMS ALGORITHM
The least mean squares (LMS) algorithms adjust the filter coefficients to minimize the cost
function. So LMS algorithm is important because of its simplicity and ease of computation [13].
The standard LMS algorithm performs the following operations to update the coefficients of an
adaptive filter:
• Calculates the output signal y(n) from the adaptive filter
• Calculates the error signal e (n) by using the following equation [14]: e (n) = d (n) – y
(n); d(n)= desired signal
• Updates the filter coefficients by using the following equation [15]:
ݓෝ(݊ + 1) = ݓෝ(݊) + ߤ. ݁(݊). ݑො(݊) (13)
Where µ is the step size of the adaptive filter, ݓෝ(n) is the filter coefficients vector, and ݑො(݊) is the
filter input vector. The normalized LMS (NLMS) algorithm is a modified form of the standard
LMS algorithm [16]. The NLMS algorithm updates the coefficients of an adaptive
filter by using the following equation:
ݓෝ(݊ + 1) = ݓෝ(݊) + ߤ. ݁(݊).
௨ෝ()
∥ ௨ෝ()∥మ (14)
3.3 FILTER DESIGN AND ANALYSIS TOOL (FDA Tool)
The Filter Design and Analysis Tool (FDA Tool) is a powerful user interface for designing and
analyzing filters swiftly. FDA Tool enables to design digital FIR or IIR filters by setting filter
specifications, by importing filters from MATLAB workspace, or by adding, moving or deleting
poles and zeros. FDA Tool also provides tools for analyzing filters, such as magnitude and phase
response and pole-zero plots [17].
3.4 VECTOR SCOPE
The Vector Scope block is a comprehensive display tool similar to a digital oscilloscope. The
block can display time-domain, frequency-domain, or user-defined signals. The input to the
Vector Scope block can be any real-valued M-by-N matrix, column or row vector, or 1-D
(Dimensional) vector, where 1-D vectors are treated as column vectors. Regardless of the input
frame status, the block treats each column of an M-by-N input as an independent channel of data
with M consecutive samples [18].
3.5 OPERATION OF SIMULATION BLOCK DIAGRAM
Consider three sinusoidal signals A1, B1 and C1 as shown in Figure6. Let the amplitudes of A1,
B1and C1 are 0.5, 2 and 5 respectively and the frequencies are 0.4Hz, 0.25Hz and 0.125Hz
respectively. These three sinusoidal signals are combined applying superposition principle by
adder block. The output of the adder block is a composite signal. The composite signal is now
applied at the input of two input sum block and the vector scope input. A random source produces
a random signal (noise signal) and the random signal is applied at the input of a LMS filter. At the
same time the random signal is passed through a digital filter that produces a low frequency noise
signal. The low frequency noise signal is then applied at the desired input of the LMS filter and at
the input of the sum block. The output of the sum block is a noisy composite signal and applied at
the input of other sum block and vector scope input. The output of the LMS filter is then applied
at the sum block input. The output of the sum block is the noiseless composite signal. The three
sinusoidal signals are reconstructed by applying digital filter bank that is shown in Figure 10.
9. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
23
Finally noiseless composite signal and reconstructed signals are obtained which are shown in
Figure 12 and figure 13.
Figure 10. Filter combinations block (containing three digital FIR filters)
4. RESULTS AND DISCUSSION
From Figure 12, it is observed that the noiseless composite signal is perfectly obtained from noisy
composite signal by using digital filter bank. So the error signal represents zero. It is also
observed that the reconstructed signals are exactly same as the input sinusoidal signals (shown in
figure 13). This means that the amplitudes, frequencies and shape of reconstructed signals are
similar as the input sinusoidal signals. Therefore, perfect noise reduction and reconstruction are
obtained. The comparison among input sinusoidal signals and reconstructed signals according to
their amplitudes are shown in table 1 and table 2. From the two tables, it is observed that the
amplitudes of input sinusoidal signals are exactly same as the output reconstructed signals.
10. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
24
Figure 11. Composite signal (contains three input sinusoidal signals) and input sine wave A1, B1 and C1
respectively
11. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
25
Figure 12. Composite signal, Noisy composite signal, Noiseless composite signal and Error respectively
12. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
26
Figure 13. Reconstructed sine wave A1, sine wave B1, sine wave C1 and zero error respectively
14. Signal & Image Processing : An International Journal (SIPIJ) Vol.6, No.2, April 2015
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[13] Ch. Santhi Rani, Dr. P. V. Subbaiah & Dr. K. Chennakesava Reddy (Sep.-December 2008) “LMS and
RLS Algorithms for Smart Antennas in a CDMA Mobile Communication Environment”,
International Journal of the Computer, the Internet Management, Vol. 16, No. 3, pp. 16.
[14] A. Bhavani Sankar, D. Kumar & K. Seethalakshmi, “Performance Study of Various Adaptive Filter
Algorithms for Noise Cancellation in Respiratory Signals”, Signal Processing: An International
Journal ( SPIJ), Vol. 4, Issue 5, pp. 271-272.
[15] Ajjaiah H.B.M, P.V. Hunagund, Manoj Kumar Singh & P.V. Rao. (2012) “Adaptive Variable Step
Size in LMS Algorithm Using Evolutionary Programming: VSSLMSEV”, Signal Processing: An
International Journal (SPIJ), Vol. 6, Issue 2, pp. 78-79.
[16] http://sine.ni.com/nips/cds/view/p/lang/en/nid/205382
[17] www.mathworks.com/products/.../examples.html?.../introfdatooldem
[18] http://www.mathworks.com/help/dsp/ref/lmsfilter.html
AUTHORS
Kawser Ahammed received B.Sc. degree in Applied Physics, Electronics &
Communication Engineering and MS degree in Applied Physics, Electronics &
Communication Engineering from University of Dhaka, Dhaka, Bangladesh, in 2011
and 2012 respectively. He has published 3 international research papers. His research
interests are in the areas of Signal Processing, Image Processing and Communications.
He is currently trying to pursue a Doctoral Degree in Electrical Engineering from USA.
Md. Ershadullah received B.Sc. degree in Applied Physics, Electronics &
Communication Engineering from University of Dhaka, Dhaka, Bangladesh, in 2011.
Now he is working as a Senior System Engineer in MAKS Renewable Energy
Company Limited, Bangladesh. In previous he worked as a Design & Service Engineer
in Solar Intercontinental (Solar-IC) Limited, Bangladesh.
Md. Rakebul Islam Heru received B.Sc. in Applied Physics, Electronics &
Communication Engineering from University of Dhaka, Dhaka, Bangladesh, in 2011.
Now he is working as an Assistant Maintenance Engineer at IT operation &
Communication Department in Bangladesh Bank (Central Bank of Bangladesh).
Saiful Islam is a B.Sc. final year student of Electrical & Electronic Engineering,
University of Dhaka, Dhaka, Bangladesh. His research interests are in the areas of
Biomedical image processing and Signal processing. At present, he is pursuing his
B.Sc. final year project work in National Institute of Nuclear Medicine and Allied
Sciences, BSMMU Campus, Shahbag, Dhaka, Bangladesh.
Dr. Z. M. Parvez Sazzad received B.Sc. degree in Applied Physics & Electronics and
MS degree in Applied Physics & Electronics from University of Dhaka, Dhaka,
Bangladesh, in 1993 and 1994 respectively. He received his PhD program from
Graduate School of Science and Engineering, University of Toyama, Japan, on March,
in 2008. He also received Post-Doc from Japan and France. He is currently working as
a Professor at Department of Electrical & Electronic Engineering (Former Applied
Physics, Electronics & Communication Engineering) in University of Dhaka, Dhaka,
Bangladesh. He has published 40 more papers in National and international journals and conferences. His
research interests are in the areas of Image / Video quality, Image/Video Compression, Image analysis and
segmentation, Motion Estimation, Biomedical image processing, Stereoscopic or multiview imaging,
Multimedia communication and broadcasting.