This document describes research into creating a user-modulated function generator to project patterns using a biaxial fast-scanning mirror. To test the scanning mirror, a laser pattern must be simulated using an arbitrary waveform generator. MATLAB was used to create a program that generates a user-defined square wave function by modulating pulse widths. The function was successfully output to an oscilloscope via an Agilent arbitrary waveform generator using MATLAB drivers. Future work involves synchronizing the function with the scanning mirror oscillations and testing with the mirror system.
Design of Linear Array Transducer Using Ultrasound Simulation Program Field-IIinventy
This paper analyze the effect of number of elements of linear array and frequency influence the
image quality in a homogenous medium. Linear arrays are most common for conventional ultrasound imaging,
because of the advantages of electronic focusing and steering. Propagation of ultrasound in biological tissues is
of nonlinear in nature. But linear approximation in far-field is promising solution to model and simulate the
real time ultrasound wave propagation. The simulation of ultrasound imaging using linear acoustics has been
most widely used for understanding focusing, image formation and flow estimation, and it has become a
standard tool in ultrasound research. . In this paper the ultrasound field generated from linear array transducer
and propagation through biological tissues is modeled and simulated using FIELD II program.
Leader Follower Formation Control of Ground Vehicles Using Dynamic Pixel Coun...ijma
This paper deals with leader-follower formations of non-holonomic mobile robots, introducing a formation
control strategy based on pixel counts using a commercial grade electro optics camera. Localization of the
leader for motions along line of sight as well as the obliquely inclined directions are considered based on
pixel variation of the images by referencing to two arbitrarily designated positions in the image frames.
Based on an established relationship between the displacement of the camera movement along the viewing
direction and the difference in pixel counts between reference points in the images, the range and the angle
estimate between the follower camera and the leader is calculated. The Inverse Perspective Transform is
used to account for non linear relationship between the height of vehicle in a forward facing image and its
distance from the camera. The formulation is validated with experiments.
This is a slide for IEEE International Conference on Computational Photography (ICCP) 2016 in Northwestern University.
See for details: http://omilab.naist.jp/project/LFseg/
An Assessment of Image Matching Algorithms in Depth EstimationCSCJournals
Computer vision is often used with mobile robot for feature tracking, landmark sensing, and obstacle detection. Almost all high-end robotics systems are now equipped with pairs of cameras arranged to provide depth perception. In stereo vision application, the disparity between the stereo images allows depth estimation within a scene. Detecting conjugate pair in stereo images is a challenging problem known as the correspondence problem. The goal of this research is to assess the performance of SIFT, MSER, and SURF, the well known matching algorithms, in solving the correspondence problem and then in estimating the depth within the scene. The results of each algorithm are evaluated and presented. The conclusion and recommendations for future works, lead towards the improvement of these powerful algorithms to achieve a higher level of efficiency within the scope of their performance.
Real Time Implementation of Adaptive Beam former for Phased Array Radar over ...CSCJournals
Mechanical positioners, rotating antennas and large size of early generation radars limited the capability of the radar system to track laterally accelerating targets. Electronic Scanning Array (ESA) such as used in Phased Array Radar (PAR) overcomed these limitations by providing beam agility, good response time, variable scan rates and efficient use of energy. Early PAR systems used analog phase shifting schemes that caused variations and component failures resulting in overall degradation of radar performance. With the advent of new technology and high performance embedded systems, digital beamforming has become powerful enough to perform massive operations required for real time digital beamforming. MATLAB simulation of adaptive beamformer is presented in this paper. Real time implementation of adaptive beamformer over DSP kit (TMS320C6713) was also carried out and results were compared with MATLAB simulations. GUI was also made in MATLAB for viewing results of real time implementation via real time data exchange. Developed system can be used in digital beamforming PAR provided array signals is routed to DSP kit through FPGA interfaced to high speed ADC’s.
Implementation of Implantation-Stagger Measuring Unit using Image ProcessingDr. Amarjeet Singh
The electrical traction system of railways is a combination of physical upright structures and OCL(Overhead Contact Lines). The horizontal distance from the center of the track to the OHE mast called implantation, horizontal displacement of overhead contact wire with respect to the center of the railway track called stagger, and the perpendicular height of overhead contact wire from the ground are periodically checked by a lineman in order to ensure a safe distance from the railway track. In this paper, we have put forth an idea of building a distance measuring device to measure the implantation and stagger without touching the objects using Open CV on raspberry pi with a camera module which will be placed at the center of the track. The system will be having two features. To measure the distance of the nearest poles, the camera has to be placed facing the mast perpendicular to a circle of diameter appropriate which is placed on the pole for measurement purposes. And to measure the stagger, the camera has to be placed facing the overhead wire from the center of the track.
Design of Linear Array Transducer Using Ultrasound Simulation Program Field-IIinventy
This paper analyze the effect of number of elements of linear array and frequency influence the
image quality in a homogenous medium. Linear arrays are most common for conventional ultrasound imaging,
because of the advantages of electronic focusing and steering. Propagation of ultrasound in biological tissues is
of nonlinear in nature. But linear approximation in far-field is promising solution to model and simulate the
real time ultrasound wave propagation. The simulation of ultrasound imaging using linear acoustics has been
most widely used for understanding focusing, image formation and flow estimation, and it has become a
standard tool in ultrasound research. . In this paper the ultrasound field generated from linear array transducer
and propagation through biological tissues is modeled and simulated using FIELD II program.
Leader Follower Formation Control of Ground Vehicles Using Dynamic Pixel Coun...ijma
This paper deals with leader-follower formations of non-holonomic mobile robots, introducing a formation
control strategy based on pixel counts using a commercial grade electro optics camera. Localization of the
leader for motions along line of sight as well as the obliquely inclined directions are considered based on
pixel variation of the images by referencing to two arbitrarily designated positions in the image frames.
Based on an established relationship between the displacement of the camera movement along the viewing
direction and the difference in pixel counts between reference points in the images, the range and the angle
estimate between the follower camera and the leader is calculated. The Inverse Perspective Transform is
used to account for non linear relationship between the height of vehicle in a forward facing image and its
distance from the camera. The formulation is validated with experiments.
This is a slide for IEEE International Conference on Computational Photography (ICCP) 2016 in Northwestern University.
See for details: http://omilab.naist.jp/project/LFseg/
An Assessment of Image Matching Algorithms in Depth EstimationCSCJournals
Computer vision is often used with mobile robot for feature tracking, landmark sensing, and obstacle detection. Almost all high-end robotics systems are now equipped with pairs of cameras arranged to provide depth perception. In stereo vision application, the disparity between the stereo images allows depth estimation within a scene. Detecting conjugate pair in stereo images is a challenging problem known as the correspondence problem. The goal of this research is to assess the performance of SIFT, MSER, and SURF, the well known matching algorithms, in solving the correspondence problem and then in estimating the depth within the scene. The results of each algorithm are evaluated and presented. The conclusion and recommendations for future works, lead towards the improvement of these powerful algorithms to achieve a higher level of efficiency within the scope of their performance.
Real Time Implementation of Adaptive Beam former for Phased Array Radar over ...CSCJournals
Mechanical positioners, rotating antennas and large size of early generation radars limited the capability of the radar system to track laterally accelerating targets. Electronic Scanning Array (ESA) such as used in Phased Array Radar (PAR) overcomed these limitations by providing beam agility, good response time, variable scan rates and efficient use of energy. Early PAR systems used analog phase shifting schemes that caused variations and component failures resulting in overall degradation of radar performance. With the advent of new technology and high performance embedded systems, digital beamforming has become powerful enough to perform massive operations required for real time digital beamforming. MATLAB simulation of adaptive beamformer is presented in this paper. Real time implementation of adaptive beamformer over DSP kit (TMS320C6713) was also carried out and results were compared with MATLAB simulations. GUI was also made in MATLAB for viewing results of real time implementation via real time data exchange. Developed system can be used in digital beamforming PAR provided array signals is routed to DSP kit through FPGA interfaced to high speed ADC’s.
Implementation of Implantation-Stagger Measuring Unit using Image ProcessingDr. Amarjeet Singh
The electrical traction system of railways is a combination of physical upright structures and OCL(Overhead Contact Lines). The horizontal distance from the center of the track to the OHE mast called implantation, horizontal displacement of overhead contact wire with respect to the center of the railway track called stagger, and the perpendicular height of overhead contact wire from the ground are periodically checked by a lineman in order to ensure a safe distance from the railway track. In this paper, we have put forth an idea of building a distance measuring device to measure the implantation and stagger without touching the objects using Open CV on raspberry pi with a camera module which will be placed at the center of the track. The system will be having two features. To measure the distance of the nearest poles, the camera has to be placed facing the mast perpendicular to a circle of diameter appropriate which is placed on the pole for measurement purposes. And to measure the stagger, the camera has to be placed facing the overhead wire from the center of the track.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
Fast and High-Precision 3D Tracking and Position Measurement with MEMS Microm...Ping Hsu
We demonstrate real-time fast-motion tracking of an object in a 3D volume, while obtaining its precise XYZ co-ordinates.
Two separate scanning MEMS micromirror sub-systems track the object in a 20 kHz closed-loop. A demonstration system capable
of tracking full-speed human hand motion provides position information at up to 5m distance with 16-bit precision, or <=20μm
precision on the X and Y axes (up/down, left/right,) and precision on the depth (Z-axis) from 10μm to 1.5mm, depending on distance.
Sidelobe rejection in a uniform linear array antenna using windowing techniqueseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Feature based ghost removal in high dynamic range imagingijcga
This paper presents a technique to reduce the ghost artifacts
in a high dynamic range (HDR) image. In HDR
imaging, we need to detect the motion between multiple exp
osure images of the same scene in order to
prevent the ghost artifacts
. First, w
e
establish
correspondences between the aligned reference image and the
other exposure images using the zero
-
mean normalized cross correlation (ZNCC
).
T
hen
, we
find object
moti
on regions
using
adaptive local thresholding of ZNCC feature maps and motion map clustering. In this
process, we focus on finding accurate motion regions and on reducing false detection in order to minimize
the side effects as well.
Through
experiments wit
h several sets of
low dynamic range
images captured with
different exposures, we show that the proposed method can remove the ghost artifacts better than existing
methods
.
DeepVO - Towards Visual Odometry with Deep LearningJacky Liu
Author:
Sen Wang1,2, Ronald Clark2, Hongkai Wen2 and Niki Trigoni2
1. Edinburgh Centre for Robotics, Heriot-Watt University, UK
2. University of Oxford, UK
Download this paper: http://senwang.gitlab.io/DeepVO/#paper
Watch video: http://senwang.gitlab.io/DeepVO/#video
DETERMINATION OF SPATIAL RESOLUTION IN COMPUTED RADIOGRAPHY (CR) BY COMPARING...AM Publications
The QC (Quality Control) testing of spatial resolution in CR (Computed Radiography) using ESF-PSF and IP-PSF methods has been investigated. The object used in this study is a phantom made of copper with 15 cm both in lenght and widht, and 1 mm in thickness. The exposure to phantom was occured with some variation of voltage, i.e. 50 kV, 60 kV, 70 kV and 80 kV for CR system. Current variation wass performed by four times for each voltage, i.e. 1.6 mAs; 4 mAs; 16 mAs and 32 mAs. Digital image data used for the acquisition is in the DICOM format. Measurement of image's spatial resolution wass performed by calculate the value of FWHM as an indicator of good or poor spatial resolution of images. Measurement of FWHM value has performed by using MATLAB R2015b and Corel Draw X7 programs. The FWHM value was obtained from gaussian function which provides a complete information on opaqueness effects that occur in images. The results showed that the best value of spatial resolution for the ESF-PSF methode is 2.50 lp/mm and the worst value is 2.36 lp/mm, while for the best resolution using IP-PSF is 2.85 lp/mm and worst is 1.01 lp/mm. The value of spatial resolution is proportional to the voltage of the tube, where the higher voltage provides the higher value of spatial resolution. But the value of spatial resolution has decreased with the current variation due to the higher current of mobile X-ray's tube.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
Fast and High-Precision 3D Tracking and Position Measurement with MEMS Microm...Ping Hsu
We demonstrate real-time fast-motion tracking of an object in a 3D volume, while obtaining its precise XYZ co-ordinates.
Two separate scanning MEMS micromirror sub-systems track the object in a 20 kHz closed-loop. A demonstration system capable
of tracking full-speed human hand motion provides position information at up to 5m distance with 16-bit precision, or <=20μm
precision on the X and Y axes (up/down, left/right,) and precision on the depth (Z-axis) from 10μm to 1.5mm, depending on distance.
Sidelobe rejection in a uniform linear array antenna using windowing techniqueseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Feature based ghost removal in high dynamic range imagingijcga
This paper presents a technique to reduce the ghost artifacts
in a high dynamic range (HDR) image. In HDR
imaging, we need to detect the motion between multiple exp
osure images of the same scene in order to
prevent the ghost artifacts
. First, w
e
establish
correspondences between the aligned reference image and the
other exposure images using the zero
-
mean normalized cross correlation (ZNCC
).
T
hen
, we
find object
moti
on regions
using
adaptive local thresholding of ZNCC feature maps and motion map clustering. In this
process, we focus on finding accurate motion regions and on reducing false detection in order to minimize
the side effects as well.
Through
experiments wit
h several sets of
low dynamic range
images captured with
different exposures, we show that the proposed method can remove the ghost artifacts better than existing
methods
.
DeepVO - Towards Visual Odometry with Deep LearningJacky Liu
Author:
Sen Wang1,2, Ronald Clark2, Hongkai Wen2 and Niki Trigoni2
1. Edinburgh Centre for Robotics, Heriot-Watt University, UK
2. University of Oxford, UK
Download this paper: http://senwang.gitlab.io/DeepVO/#paper
Watch video: http://senwang.gitlab.io/DeepVO/#video
DETERMINATION OF SPATIAL RESOLUTION IN COMPUTED RADIOGRAPHY (CR) BY COMPARING...AM Publications
The QC (Quality Control) testing of spatial resolution in CR (Computed Radiography) using ESF-PSF and IP-PSF methods has been investigated. The object used in this study is a phantom made of copper with 15 cm both in lenght and widht, and 1 mm in thickness. The exposure to phantom was occured with some variation of voltage, i.e. 50 kV, 60 kV, 70 kV and 80 kV for CR system. Current variation wass performed by four times for each voltage, i.e. 1.6 mAs; 4 mAs; 16 mAs and 32 mAs. Digital image data used for the acquisition is in the DICOM format. Measurement of image's spatial resolution wass performed by calculate the value of FWHM as an indicator of good or poor spatial resolution of images. Measurement of FWHM value has performed by using MATLAB R2015b and Corel Draw X7 programs. The FWHM value was obtained from gaussian function which provides a complete information on opaqueness effects that occur in images. The results showed that the best value of spatial resolution for the ESF-PSF methode is 2.50 lp/mm and the worst value is 2.36 lp/mm, while for the best resolution using IP-PSF is 2.85 lp/mm and worst is 1.01 lp/mm. The value of spatial resolution is proportional to the voltage of the tube, where the higher voltage provides the higher value of spatial resolution. But the value of spatial resolution has decreased with the current variation due to the higher current of mobile X-ray's tube.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Determining the Efficient Subband Coefficients of Biorthogonal Wavelet for Gr...CSCJournals
In this paper, we propose an invisible blind watermarking scheme for the gray-level images. The cover image is decomposed using the Discrete Wavelet Transform with Biorthogonal wavelet filters and the watermark is embedded into significant coefficients of the transformation. The Biorthogonal wavelet is used because it has the property of perfect reconstruction and smoothness. The proposed scheme embeds a monochrome watermark into a gray-level image. In the embedding process, we use a localized decomposition, means that the second level decomposition is performed on the detail sub-band resulting from the first level decomposition. The image is decomposed into first level and for second level decomposition we consider Horizontal, vertical and diagonal subband separately. From this second level decomposition we take the respective Horizontal, vertical and diagonal coefficients for embedding the watermark. The robustness of the scheme is tested by considering the different types of image processing attacks like blurring, cropping, sharpening, Gaussian filtering and salt and pepper noise effect. The experimental result shows that the embedding watermark into diagonal subband coefficients is robust against different types of attacks.
Segmentation Based Multilevel Wide Band Compression for SAR Images Using Coif...CSCJournals
Synthetic aperture radar (SAR) data represents a significant resource of information for a large variety of researchers. Thus, there is a strong interest in developing data encoding and decoding algorithms which can obtain higher compression ratios while keeping image quality to an acceptable level. In this work, results of different wavelet-based image compression and segmentation based wavelet image compression are assessed through controlled experiments on synthetic SAR images. The effects of dissimilar wavelet functions, number of decompositions are examined in order to find optimal family for SAR images. The choice of optimal wavelets in segmentation based wavelet image compression is coiflet for low frequency and high frequency component. The results presented here is a good reference for SAR application developers to choose the wavelet families and also it concludes that wavelets transform is rapid, robust and reliable tool for SAR image compression. Numerical results confirm the potency of this approach.
A complete user adaptive antenna tutorial demonstration. a gui based approach...Pablo Velarde A
This paper is aimed at creation of an easy to use
Antenna Graphical User Interface(GUI) Tutorial Demonstration
using JAVA in BlueJ environment which provides the user with
ample opportunity to feed desired input parameters and to study
the basic antenna patterns and parameters according to the
inputs using MATLAB® interfacing. It also presents three
dimensional physical appearances using the JAVA3D utility
Abstract— This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be ~15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Abstract:
This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be 15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Development of Seakeeping Test and Data Processing Systemijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This report briefly summarizes the topics I have explored during my Internship in the summer of 2019 under Dr. Anil Prabhakar, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai-600036
Development of Compact P-Band Vector Reflectometer IJECEIAES
A compact and low cost portable vector reflectometer is designed for a reliable measurement of reflection coefficient, S . This reflectometer focuses on return loss measurement of frequency ranges from 450 MHz to 550 MHz. The detection of magnitude and phase is based on the utilization of surface mount Analog Devices AD8302 gain/phase detector. The data acquisition is controlled by using Arduino-Nano 3.0 microcontroller, with the use of two analog to digital converter (ADC) and a digital to analog converter (DAC). One port (Open, short and matched load) calibration technique is used to eliminate systematic errors prior to data acquisition. The evaluation of the reflectometer is done by comparing the result of the measurement to that of vector network analyzer. 11
Wavelet based detection and location of faults in 400kv, 50km Underground Po...
Salamanca_Research_Paper
1. User Modulated Function Generator for Projecting a Pattern via a
Biaxial Wide-field Fast-scanning Mirror
Carlos Salamanca
Department of Electrical and Computer Engineering, Texas A&M University,
College Station, TX 77843
ABSTRACT
The device shown and used in this research is a wide-field fast-scanning optical-resolution
photoacoustics microscopy (OR-PAM), water-immersible microelectromechanical systems (MEMS)
scanning mirror. The scanning mirror oscillates between an angle to deflect photoacoustic waves to create
images. The focus of this study is primarily on the laser beam’s intensity. To test the scanning mirror, a
laser pattern must be simulated. The goal is to create a user defined waveform that will synchronize with
the scanning mirror's oscillation to create a desired pattern. More specifically, it is to create patterns
resembling the Arabic numerical characters: 0, 1, 2... To change the projected pattern the beam’s intensity
function needs to be altered. The arbitrary waveform generator (AWG) provided for this study is an
Agilent 33210A. The AWG can generate a square wave, which is the best waveform to use in this
scenario. It is the best waveform to simulate digital data and to make programming the logic simpler. By
changing the duty cycle of square wave, the pulse-width can be modulated to fit the pattern desired. As
a result of this research a MATLAB application (compatible with an Agilent 33210A) has been created
to generate a user-defined function.
Keywords: MEMS scanning mirror, arbitrary waveform generator, pulse-width modulation
1. Introduction
In the field of laser scanning, scanning mirrors are used for the deflection of visible or invisible beams
of laser [1]. This technology is most commonly found in laser printers. Laser deflection can also be found
in 3D object scanners and laser rangefinders. Although these devices use electromagnetic waves (light),
some scanning mirrors can be used with photoacoustics. They are highly desired for ultrasound and
microscopic imaging [2].
The scanning mirror can scan about two axes. The scanning mirror is based on electromagnetic actuators
that consist of planar coils and permanent magnets [3].
Figure 1. Prototype of an immersible scanning mirror [2]
The device shown and used in this research is a wide-field fast-scanning optical-resolution
2. photoacoustics microscopy (OR-PAM), water-immersible microelectromechanical systems (MEMS)
scanning mirror. The scanning mirror oscillates between an angle to deflect light to create images at the
anatomical, chemical, functional, and metabolic level [4].
Figure 2. Laser-scanning mirror system [2]
The focus of this study is primarily on the laser beam’s intensity. To test the scanning mirror, a laser
pattern must be simulated. The goal is to create a user defined waveform that will synchronize with the
scanning mirror's oscillation to create a desired pattern.
2. Methodology
2.1 Defining the Problem
To simplify the problem further and generalize the solution, the goal is to create patterns resembling the
Arabic numerical characters: 0, 1, 2... and so on. Assuming, that a beam of light is constant, the resulting
pattern would be a “zig-zag” (triangle wave) pattern.
Figure 3. Two-dimensional oscillating pattern results in a zig-zag
Changing the frequency of the light source to half would result in the following pattern.
3. Figure 4. Changing the frequency of the light source changes the pattern.
2.2 Approach
The arbitrary waveform generator (AWG) provided for this study is an Agilent 33210A. The AWG can
generate a variety of waveforms. The waveforms are important because the change in amplitude of the
wave correlates to the change in intensity of the light source.
Figure 5. Agilent 33210AArbitrary Waveform Generator [5]
Figure 6. Common waveforms generated by AWGs.
-By Omegatron/CC BY-SA 3.0
The square waveform is the best waveform to use in this scenario. It is the best waveform to simulate
4. digital data. This is important because it makes programming the logic simpler. The interest lies when
the intensity of the light source is at max (1) or when it is off (0). Therefore, using the square waveform
allows the program to just focus on modulating the frequency, or the pulse-width, of the waveform. This
can be likened to when digital data is encoded into Morse code [6]. In Morse code, there are two widths
in the ON-state: short and long. The program would need to allow the user to change the widths at will.
In a sine wave, the width is defined as the wave length, but in a square wave it can be manipulated by
changing the duty cycle of the wave. The duty cycle is the percentage of one period in which the signal
is in the ON-state [7].
Figure 7. The top signal has a 75% duty cycle and the lower signal has a 25% duty cycle
Changing the pulse-widths on a square wave changes the frequency of the light source thus changing the
pattern that results from the scanning mirror. To determine the desired pulse-widths, the desired pattern
needs to be determined. The question is posed: how will the numeric characters appear based on the
oscillation of the scanning mirror?
Figure 8. Sketch of numeric character on projected area
In figure 8, the black path shows how the beam would travel if it were in the ON-state the entire path.
The red portions are when the beam should be on the ON-state to get the desired character. Because, the
scanning mirror pivots about, two axes, it will have two periods: Tx and Ty. According to the projection
shown in figure 8, the mirror oscillates in the x-direction twelve times for every one oscillation in the y-
direction.
5. Figure 9. Prediction of what the signal should look like
Figure 10. On the second half of the y-oscillation, the pattern is reversed
The horizontal axis corresponds to the period of the oscillation in the x-direction. The vertical axis
corresponds to the amplitude of the signal, 1 (ON) or 0 (OFF). The variable ta is the longer widths and
the tb is the shorter widths. This signal in figure 9 only applies while the scanning mirror is in the first
half of its oscillation in the y-direction. The signal in figure 10 is for the second half.
3. Programming
3.1 Agilent Waveform Editor
Figure 11. Agilent Waveform Editor
6. The AWG that is provided comes with software where a user can define a custom waveform. The problem
with this setup is completely dependent on the user’s input. There would be no way to synchronize the
defined function with the scanning mirror’s oscillation.
3.2 LabVIEW
National Instruments (NI) LabVIEW offers more flexibility with its data acquisition and signal
processing libraries [8]. To get an idea of what a user-defined function would look like, a VI (LabVIEW
code) was taken from the community support on the NI website [9].
Figure 12. This is the block diagram, or the actual programming “code”
Figure 13. This is the user interface, or the inputs and outputs of the program
The VI actually creates one pulse at a time, and then it is stored. When the new pulse is created, the string
of pulses then overwrites what is currently showing on the waveform graph. Although, this program
allows a user to create a defined-square function, it is still clumsy and difficult to use and modify.
3.3 MATLAB
After, some research it was determined that m-file (MATLAB scripts) can be used in LabVIEW. This is
important because MATLAB is better for handling signal generation and LabVIEW is better suited for
7. signal processing [9].
Figure 14. User-Defined Square Wave Generator
The MATLAB script that produced figure 14 allows the user to modulate the width of the pulses
independently from each other. This is what allows varying pulse widths. The script also allows the user
to define the time locations of each pulse. In practicality, the time locations would be synchronized with
the oscillations of the scanning mirror.
3.4 Hybrid Application
To make the time locations of the pulses dependent on time stamps, it would be best to integrate the
MATLAB script into a LabVIEW vi.
Figure 15. Front Panel of Hybrid Application
The front panel shown in figure 15 is the LabVIEW interface for the MATLAB script. The panel allows
a user to control the cycles, period, sample rate, pulse widths, and pulse locations without modifying
the m-script. Although this application gives full control to the user, it does not have any compatibility
8. with the Agilent AWG.
4. Testing and Results
4.1 Agilent Drivers
National Instruments has a program that allows a user to connect to an external instrument via a network
or tether connection. The feature is called NI VISA [10]. NI VISA allows LabVIEW to recognize the
AWG as an instrument capable of receiving and sending data. Agilent also provides LabVIEW libraries
to be able to configure waveform settings.
To test the Agilent drivers, I ran a sample program in the Agilent library to verify that LabVIEW can
communicate with the Agilent AWG. Agilent also comes with its own VISA called Agilent IO. Agilent
IO allowed for universal communication regardless of software.
4.2 Hybrid Application
After the hybrid application was completed, it was tested using NI VISA. The AWG was connected to a
PC with the hybrid application via USB connection. The AWG was then connected to an oscilloscope to
verify the output signal.
Because of LabVIEW’s GUI (graphical user interface), the application allowed the function to be
manipulated. Unfortunately, the AWG was having difficulties reading the inputted function from the
hybrid application.
4.3 Final MATLAB Application
Agilent provided guidance on how to directly integrate the AWG with MATLAB [11]. Through this
finding, the entire LabVIEW aspect of the application was removed. To verify the publication, a sample
waveform was programmed and executed. Because LabVIEW was removed, NI VISA became
ineffective for instrument communication. Finding the recommended MATLAB drivers also became
difficult.
MathWorks provided documentation on communicating with an Agilent instrument using the Agilent IO
VISApackaged with the AWG. With the Agilent VISA, the sample waveform was executed successfully.
After editing the communications part of the m-script, the application was executed and produced figure
16.
Figure 16. Oscilloscope displaying the output of the AWG
9. 5. Conclusions
From the tests conducted, the conclusions has been drawn that a user modulated function can be
generated. Through the application created, the pulse locations can be synchronized with that of
oscillation of the scanning mirror. The program also allows the user to control the amount of varying
pulse widths, the magnitude of the widths, the output voltage, and the individual time locations of each
pulse.
6. Proposed Future Work
Agraphical user interface is not necessary, but is highly recommended to efficiently control the properties
of a function. More importantly, it is necessary to modify the code to be able to synchronize the function
with the oscillation frequency of the scanning mirror. Once the code is modified, the function generator
needs to be tested with the scanning mirror system to determine the necessary function to produce a
desired pattern.
7. Acknowledgments
This research was supported by the National Science Foundation Research Experience for
Undergraduates (REU) program on Interdisciplinary Research on Mechatronics, Robotics, and
Automated System Design (NSF grant no. 1263293). Any opinions, findings, and conclusions or
recommendations expressed in this material are those of the author(s) and do not necessarily reflect the
views of the National Science Foundation. Many thanks go to Dr. Jun Zou for opening the opportunity
to perform research under his supervision and to Song Xu for his direct mentorship throughout the
project.
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