International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Histogram Equalization with Range Offset for Brightness Preserved Image Enhan...CSCJournals
In this paper, a simple modification to Global Histogram Equalization (GHE), a well known digital image enhancement method, has been proposed. This proposed method known as Histogram Equalization with Range Offset (HERO) is divided into two stages. In its first stage, an intensity mapping function is constructed by using the cumulative density function of the input image, similar to GHE. Then, during the second stage, an offset for the intensity mapping function will be determined to maintain the mean brightness of the image, which is a crucial criterion for digital image enhancement in consumer electronic products. Comparison with some of the current histogram equalization based enhancement methods shows that HERO successfully preserves the mean brightness and give good enhancement to the image.
7 ijaems sept-2015-8-design and implementation of fuzzy logic based image fus...INFOGAIN PUBLICATION
The quality of image holds importance for both humans and machines. To fulfill the requirement of good quality images, image enhancement is needed. Application of a single contrast enhancement technique often does not produce desirable result and may lead to over enhanced images. To overcome this problem image fusion is performed so that better results with desired enhancement can be achieved. In the present paper an amalgamation of image enhancement, fusion and sharpening have been carried out in the candidate algorithm. The algorithm makes use of fuzzy logic for weight calculation. The results are compared with DACE/LIF approach and it is observed that the proposed algorithm improves the result in terms of quality parameters like PSNR (Peak Signal to Noise Ratio), AMBE (Absolute Mean Brightness Error) and SSIM (Structural Similarity Index) by 0.5 dB, 3 and 0.1 respectively from the existing technique.
CONTRAST ENHANCEMENT TECHNIQUES USING HISTOGRAM EQUALIZATION METHODS ON COLOR...IJCSEA Journal
Histogram equalization (HE) is a simple and widely used image contrast enhancement technique. The basic disadvantage of HE is it changes the brightness of the image. In order to overcome this drawback, various HE methods have been proposed. These methods preserves the brightness on the output image but, does not have a natural look. In order to overcome this problem the, present paper uses Multi-HE methods, which decompose the image into several sub images, and classical HE method is applied to each sub image. The algorithm is applied on various images and has been analysed using both objective and subjective assessment.
CONTRAST ENHANCEMENT AND BRIGHTNESS PRESERVATION USING MULTIDECOMPOSITION HIS...sipij
Histogram Equalization (HE) has been an essential addition to the Image Enhancement world.
Enhancement techniques like Classical Histogram Equalization(CHE),Adaptive Histogram Equalization
(AHE), Bi-Histogram Equalization (BHE) and Recursive Mean Separate Histogram Equalization (RMSHE)
methods enhance contrast, brightness is not well preserved, which gives an unpleasant look to the final
image obtained. Thus, we introduce a novel technique Multi-Decomposition Histogram Equalization
(MDHE) to eliminate the drawbacks of the earlier methods. In MDHE, we have decomposed the input
image using a unique logic, applied CHE in each of the sub-images and then finally interpolated them in
correct order. The final image after MDHE gives us the best results based on contrast enhancement and
brightness preservation aspect compared to all other techniques mentioned above. We have calculated the
various parameters like PSNR, SNR, RMSE, MSE, etc. for every technique. Our results are well supported
by bar graphs, histograms and the parameter calculations at the end.
Image enhancement plays an important role in vision applications. Recently a lot of work has been performed in the field of image enhancement. Many techniques have already been proposed till now for enhancing the digital images. This paper has presented a comparative analysis of various image enhancement techniques. This paper has shown that the fuzzy logic and histogram based techniques have quite effective results over the available techniques. This paper ends up with suitable future directions to enhance fuzzy based image enhancement technique further. In the proposed technique, an approach is made to enhance the images other than low-contrast images as well by balancing the stretching parameter (K) according to the color contrast. Proposed technique is designed to restore the degraded edges resulted due to contrast enhancement as well.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Histogram Equalization with Range Offset for Brightness Preserved Image Enhan...CSCJournals
In this paper, a simple modification to Global Histogram Equalization (GHE), a well known digital image enhancement method, has been proposed. This proposed method known as Histogram Equalization with Range Offset (HERO) is divided into two stages. In its first stage, an intensity mapping function is constructed by using the cumulative density function of the input image, similar to GHE. Then, during the second stage, an offset for the intensity mapping function will be determined to maintain the mean brightness of the image, which is a crucial criterion for digital image enhancement in consumer electronic products. Comparison with some of the current histogram equalization based enhancement methods shows that HERO successfully preserves the mean brightness and give good enhancement to the image.
7 ijaems sept-2015-8-design and implementation of fuzzy logic based image fus...INFOGAIN PUBLICATION
The quality of image holds importance for both humans and machines. To fulfill the requirement of good quality images, image enhancement is needed. Application of a single contrast enhancement technique often does not produce desirable result and may lead to over enhanced images. To overcome this problem image fusion is performed so that better results with desired enhancement can be achieved. In the present paper an amalgamation of image enhancement, fusion and sharpening have been carried out in the candidate algorithm. The algorithm makes use of fuzzy logic for weight calculation. The results are compared with DACE/LIF approach and it is observed that the proposed algorithm improves the result in terms of quality parameters like PSNR (Peak Signal to Noise Ratio), AMBE (Absolute Mean Brightness Error) and SSIM (Structural Similarity Index) by 0.5 dB, 3 and 0.1 respectively from the existing technique.
CONTRAST ENHANCEMENT TECHNIQUES USING HISTOGRAM EQUALIZATION METHODS ON COLOR...IJCSEA Journal
Histogram equalization (HE) is a simple and widely used image contrast enhancement technique. The basic disadvantage of HE is it changes the brightness of the image. In order to overcome this drawback, various HE methods have been proposed. These methods preserves the brightness on the output image but, does not have a natural look. In order to overcome this problem the, present paper uses Multi-HE methods, which decompose the image into several sub images, and classical HE method is applied to each sub image. The algorithm is applied on various images and has been analysed using both objective and subjective assessment.
CONTRAST ENHANCEMENT AND BRIGHTNESS PRESERVATION USING MULTIDECOMPOSITION HIS...sipij
Histogram Equalization (HE) has been an essential addition to the Image Enhancement world.
Enhancement techniques like Classical Histogram Equalization(CHE),Adaptive Histogram Equalization
(AHE), Bi-Histogram Equalization (BHE) and Recursive Mean Separate Histogram Equalization (RMSHE)
methods enhance contrast, brightness is not well preserved, which gives an unpleasant look to the final
image obtained. Thus, we introduce a novel technique Multi-Decomposition Histogram Equalization
(MDHE) to eliminate the drawbacks of the earlier methods. In MDHE, we have decomposed the input
image using a unique logic, applied CHE in each of the sub-images and then finally interpolated them in
correct order. The final image after MDHE gives us the best results based on contrast enhancement and
brightness preservation aspect compared to all other techniques mentioned above. We have calculated the
various parameters like PSNR, SNR, RMSE, MSE, etc. for every technique. Our results are well supported
by bar graphs, histograms and the parameter calculations at the end.
Image enhancement plays an important role in vision applications. Recently a lot of work has been performed in the field of image enhancement. Many techniques have already been proposed till now for enhancing the digital images. This paper has presented a comparative analysis of various image enhancement techniques. This paper has shown that the fuzzy logic and histogram based techniques have quite effective results over the available techniques. This paper ends up with suitable future directions to enhance fuzzy based image enhancement technique further. In the proposed technique, an approach is made to enhance the images other than low-contrast images as well by balancing the stretching parameter (K) according to the color contrast. Proposed technique is designed to restore the degraded edges resulted due to contrast enhancement as well.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Review on Image Enhancement in Spatial Domainidescitation
With the proliferation in electronic imaging devices
like in mobiles, computer vision, medical field and space field;
image enhancement field has become the quite interesting
and important area of research. These imaging devices are
viewed under a diverse range of viewing conditions and a huge
loss in contrast under bright outdoor viewing conditions; thus
viewing condition parameters such as surround effects,
correlated color temperature and ambient lighting have
become of significant importance. Therefore, Principle
objective of Image enhancement is to adjust the quality of an
image for better human visual perception. Appropriate choice
of enhancement techniques is greatly influenced by the
imaging modality, task at hand and viewing conditions.
Basically, image enhancement techniques have been classified
into two broad categories: Spatial domain image enhancement
and Frequency domain image enhancement. This survey report
gives an overview of different methodologies have been used
for enhancement under the spatial domain category. It is noted
that in this field still more research is to be done.
Image Contrast Enhancement for Brightness Preservation Based on Dynamic Stret...CSCJournals
Histogram equalization is an efficient process often employed in consumer electronic systems for image contrast enhancement. In addition to an increase in contrast, it is also required to preserve the mean brightness of an image in order to convey the true scene information to the viewer. A conventional approach is to separate the image into sub-images and then process independently by histogram equalization towards a modified profile. However, due to the variations in image contents, the histogram separation threshold greatly influences the level of shift in mean brightness with respect to the uniform histogram in the equalization process. Therefore, the choice of a proper threshold, to separate the input image into sub-images, is very critical in order to preserve the mean brightness of the output image. In this research work, a dynamic range stretching approach is adopted to reduce the shift in output image mean brightness. Moreover, the computationally efficient golden section search algorithm is applied to obtain a proper separation into sub-images to preserve the mean brightness. Experiments were carried out on a large number of color images of natural scenes. Results, as compared to current available approaches, showed that the proposed method performed satisfactorily in terms of mean brightness preservation and enhancement in image contrast.
Quality Assessment of Gray and Color Images through Image Fusion TechniqueIJEEE
. Image fusion is an emerging trend in the digital image processing to enhance images. In image fusion two or more images can be fused (combined) to obtain an enhanced image. In the present work image fusion technology has been used to enhance a given input image. Image fusion is used here to combine two images which contains complementary information.
A Novel Color Image Fusion for Multi Sensor Night Vision ImagesEditor IJCATR
In this paper presents a simple and fast color fusion approach for night vision images. Image fusion involves merging of two
or more images in such a way, to get the most advantageous characteristics of each image. Here the Visible image is fused with the
InfraRed (IR) image, so the desired result will be single, highly informative image providing full information. This paper focuses on
color constancy and color contrast problem.
Firstly the contrast of the infrared and visible image is enhanced using Local Histogram Equation. Then the two enhanced
images are fused in three compounds of a LAB image using aDWT image fusion. This paper adopts an approach which transfer color
from the reference image to the fused image using Color Transfer Technology. To enhance the contrast between the target and the
background, a scaling factor is introduced in the transferring equation in the b channel. Finally our approach gives the Multiband
Fused image with the natural day-time color appearance and the hot targets are popped out with intense colors while the background
details present with the natural color appearance.
Intensity Preserving Cast Removal in Color Images Using Particle Swarm Optimi...IJECEIAES
In this paper, we present an optimal image enhancement technique for color cast images by preserving their intensity. There are methods which improves the appearance of the affected images under different cast like red, green, blue etc but up to some extent. The proposed color cast method is corrected by using transformation function based on gamma values. These optimal values of gamma are obtained through particle swarm optimization (PSO). This technique preserves the image intensity and maintains the originality of color by satisfying the modified gray world assumptions. For the performance analysis, the image distance metric criteria of CIELAB color space is used. The effectiveness of the proposed approach is illustrated by testing the proposed method on color cast images. It has been found that distance between the reference image and the corrected proposed image is negligible. The calculated value of image distance depicts that the enhanced image results of the proposed algorithm are closer to the reference images in comparison with other existing methods.
COLOUR IMAGE ENHANCEMENT BASED ON HISTOGRAM EQUALIZATIONecij
Histogram equalization is a nonlinear technique for adjusting the contrast of an image using its
histogram. It increases the brightness of a gray scale image which is different from the mean brightness of
the original image. There are various types of Histogram equalization techniques like Histogram
Equalization, Contrast Limited Adaptive Histogram Equalization, Brightness Preserving Bi Histogram
Equalization, Dualistic Sub Image Histogram Equalization, Minimum Mean Brightness Error Bi
Histogram Equalization, Recursive Mean Separate Histogram Equalization and Recursive Sub Image
Histogram Equalization. In this paper, the histogram equalization approach of gray-level images is
extended for colour images. The acquired image is converted into HSV (Hue, Saturation, Value). The
image is then decomposed into two parts by using exposure threshold and then equalized them
independently Over enhancement is also controlled in this method by using clipping threshold. For
measuring the performance of the enhanced image, entropy and contrast are calculated.
Image Enhancement using Guided Filter for under Exposed ImagesDr. Amarjeet Singh
Image enhancement becomes an important step to
improve the quality of image and change in the appearance of
the image in such a way that either a human or a machine can
fetch certain information from the image after a change. Due
to low contrast images it becomes very difficult to get any
information out of it. In today’s digital world of imaging
image enhancement is a very useful in various applications
ranging from electronics printing to recognition. For highly
underexposed region, intensity bin are present in darken
region that’s by such images lacks in saturation and suffers
from low intensity. Power law transformation provides
solution to this problem. It enhances the brightness so as
image at least becomes visible. To modify the intensity level
histogram equalization can be used. In this we can apply
cumulative density function and probabilistic density function
so as to divide the image into sub images.
In proposed approach to provide betterment in
results guided filter has been applied to images after
equalization so that we can get better Entropy rate and
Coefficient of correlation can be improved with previously
available techniques. The guided filter is derived from local
linear model. The guided filter computes the filtering output
by considering the content of guidance image, which can be
the image itself or other targeted image.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
An Efficient Approach for Image Enhancement Based on Image Fusion with Retine...ijsrd.com
Aiming at problems of poor contrast and blurred edges in degraded images, a novel enhancement algorithm is proposed in present research. Image fusion refers to a technique that combines the information from two or more images of a scene into a single fused image.The Algorithm uses Retinex theory and gamma correction to perform a better enhancement of images. The algorithm can efficiently combine the advantages of Retinex and Gamma correction improving both color constancy and intensity of image.
Enhancement of Medical Images using Histogram Based Hybrid TechniqueINFOGAIN PUBLICATION
Digital Image Processing is very important area of research. A number of techniques are available for image enhancement of gray scale images as well as color images. They work very efficiently for enhancement of the gray scale as well as color images. Important techniques namely Histogram Equalization, BBHE, RSWHE, RSWHE (recursion=2, gamma=No), AGCWD (Recursion=0, gamma=0) have been used quite frequently for image enhancement. But there are some shortcomings of the present techniques. The major shortcoming is that while enhancement, the brightness of the image deteriorates quite a lot. So there was need for some technique for image enhancement so that while enhancement was done, the brightness of the images does not go down. To remove this shortcoming, a new hybrid technique namely RESWHE+AGCWD (recursion=2, gamma=0 or 1) was proposed. The results of the proposed technique were compared with the existing techniques. In the present methodology, the brightness did not decrease during image enhancement. So the results and the technique was validated and accepted. The parameters via PSNR, MSE, AMBE etc. are taken for performance evaluation and validation of the proposed technique against the existing techniques which results in better outperform.
Feature Extraction of an Image by Using Adaptive Filtering and Morpological S...IOSR Journals
Abstract: For enhancing an image various enhancement schemes are used which includes gray scale manipulation, filtering and Histogram Equalization, Where Histogram equalization is one of the well known image enhancement technique. It became a popular technique for contrast enhancement because it is simple and effective. The basic idea of Histogram Equalization method is to remap the gray levels of an image. Here using morphological segmentation we can get the segmented image. Morphological reconstruction is used to segment the image. Comparative analysis of different enhancement and segmentation will be carried out. This comparison will be done on the basis of subjective and objective parameters. Subjective parameter is visual quality and objective parameters are Area, Perimeter, Min and Max intensity, Avg Voxel Intensity, Std Dev of Intensity, Eccentricity, Coefficient of skewness, Coefficient of Kurtosis, Median intensity, Mode intensity. Keywords: Histogram Equalization, Segmentation, Morphological Reconstruction .
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.
MODIFIED HISTOGRAM EQUALIZATION FOR IMAGE CONTRAST ENHANCEMENT USING PARTICLE...ijcseit
A novel Modified Histogram Equalization (MHE) technique for contrast enhancement is proposed in this
paper. This technique modifies the probability density function of an image by introducing constraints prior
to the process of histogram equalization (HE). These constraints are formulated using two parameters
which are optimized using swarm intelligence. This technique of contrast enhancement takes control over
the effect of HE so that it enhances the image without causing any loss to its details. A median adjustment
factor is then added to the result to normalize the change in the luminance level after enhancement. This
factor suppresses the effect of luminance change due to the presence of outlier pixels. The outlier pixels of
highly deviated intensities have greater impact in changing the contrast of an image. This approach
provides a convenient and effective way to control the enhancement process, while being adaptive to
various types of images. Experimental results show that the proposed technique gives better results in
terms of Discrete Entropy and SSIM values than the existing histogram-based equalization methods.
A MODIFIED HISTOGRAM BASED FAST ENHANCEMENT ALGORITHMcsandit
The contrast enhancement of medical images has an important role in diseases diagnostic,
specially, cancer cases. Histogram equalization is considered as the most popular algorithm for
contrast enhancement according to its effectiveness and simplicity. In this paper, we present a
modified version of the Histogram Based Fast Enhancement Algorithm. This algorithm
enhances the areas of interest with less complexity. It is applied only to CT head images and its
idea based on treating with the soft tissues and ignoring other details in the image. The
proposed modification make the algorithm is valid for most CT image types with enhanced
results.
An image enhancement method based on gabor filtering in wavelet domain and ad...nooriasukmaningtyas
The images are not always good enough to convey the proper information.
The image may be very bright or very dark sometime or it may be low
contrast or high contrast. Because of these reasons image enhancement plays
important role in digital image processing. In this paper we proposed an
image enhancement technique in which gabor and median filtering is
performed in wavelet domain and adaptive histogram equalization is
performed in spatial domain. Brightness and contrast are the two parameters
Keywords: used for analyzing the performance of the proposed method.
Modified Contrast Enhancement using Laplacian and Gaussians Fusion Techniqueiosrjce
The aim of image fusion is to mix images of a scene captured below totally different illumination. One
image contains most of information from the whole supply images automatically. Contrast enhancement is employed
to enhance the standard of visible image with none introducing unrealistic visual appearances. Fusion technique is
employed for the important applications like medical imaging, microscopic imaging, remote sensing, and laptop
vision and robotics. Contrast enhancement improves the brightness differences within the dark, gray or bright regions
at the expense of the brightness differences within the alternative regions. During this paper methodology of the
contrast enhancement for images that improves the local image contrast by controlling the local image gradient. The
proposed methodology improves the improvement drawback and maximizes the local contrast and global contrast of
an image.
Review on Image Enhancement in Spatial Domainidescitation
With the proliferation in electronic imaging devices
like in mobiles, computer vision, medical field and space field;
image enhancement field has become the quite interesting
and important area of research. These imaging devices are
viewed under a diverse range of viewing conditions and a huge
loss in contrast under bright outdoor viewing conditions; thus
viewing condition parameters such as surround effects,
correlated color temperature and ambient lighting have
become of significant importance. Therefore, Principle
objective of Image enhancement is to adjust the quality of an
image for better human visual perception. Appropriate choice
of enhancement techniques is greatly influenced by the
imaging modality, task at hand and viewing conditions.
Basically, image enhancement techniques have been classified
into two broad categories: Spatial domain image enhancement
and Frequency domain image enhancement. This survey report
gives an overview of different methodologies have been used
for enhancement under the spatial domain category. It is noted
that in this field still more research is to be done.
Image Contrast Enhancement for Brightness Preservation Based on Dynamic Stret...CSCJournals
Histogram equalization is an efficient process often employed in consumer electronic systems for image contrast enhancement. In addition to an increase in contrast, it is also required to preserve the mean brightness of an image in order to convey the true scene information to the viewer. A conventional approach is to separate the image into sub-images and then process independently by histogram equalization towards a modified profile. However, due to the variations in image contents, the histogram separation threshold greatly influences the level of shift in mean brightness with respect to the uniform histogram in the equalization process. Therefore, the choice of a proper threshold, to separate the input image into sub-images, is very critical in order to preserve the mean brightness of the output image. In this research work, a dynamic range stretching approach is adopted to reduce the shift in output image mean brightness. Moreover, the computationally efficient golden section search algorithm is applied to obtain a proper separation into sub-images to preserve the mean brightness. Experiments were carried out on a large number of color images of natural scenes. Results, as compared to current available approaches, showed that the proposed method performed satisfactorily in terms of mean brightness preservation and enhancement in image contrast.
Quality Assessment of Gray and Color Images through Image Fusion TechniqueIJEEE
. Image fusion is an emerging trend in the digital image processing to enhance images. In image fusion two or more images can be fused (combined) to obtain an enhanced image. In the present work image fusion technology has been used to enhance a given input image. Image fusion is used here to combine two images which contains complementary information.
A Novel Color Image Fusion for Multi Sensor Night Vision ImagesEditor IJCATR
In this paper presents a simple and fast color fusion approach for night vision images. Image fusion involves merging of two
or more images in such a way, to get the most advantageous characteristics of each image. Here the Visible image is fused with the
InfraRed (IR) image, so the desired result will be single, highly informative image providing full information. This paper focuses on
color constancy and color contrast problem.
Firstly the contrast of the infrared and visible image is enhanced using Local Histogram Equation. Then the two enhanced
images are fused in three compounds of a LAB image using aDWT image fusion. This paper adopts an approach which transfer color
from the reference image to the fused image using Color Transfer Technology. To enhance the contrast between the target and the
background, a scaling factor is introduced in the transferring equation in the b channel. Finally our approach gives the Multiband
Fused image with the natural day-time color appearance and the hot targets are popped out with intense colors while the background
details present with the natural color appearance.
Intensity Preserving Cast Removal in Color Images Using Particle Swarm Optimi...IJECEIAES
In this paper, we present an optimal image enhancement technique for color cast images by preserving their intensity. There are methods which improves the appearance of the affected images under different cast like red, green, blue etc but up to some extent. The proposed color cast method is corrected by using transformation function based on gamma values. These optimal values of gamma are obtained through particle swarm optimization (PSO). This technique preserves the image intensity and maintains the originality of color by satisfying the modified gray world assumptions. For the performance analysis, the image distance metric criteria of CIELAB color space is used. The effectiveness of the proposed approach is illustrated by testing the proposed method on color cast images. It has been found that distance between the reference image and the corrected proposed image is negligible. The calculated value of image distance depicts that the enhanced image results of the proposed algorithm are closer to the reference images in comparison with other existing methods.
COLOUR IMAGE ENHANCEMENT BASED ON HISTOGRAM EQUALIZATIONecij
Histogram equalization is a nonlinear technique for adjusting the contrast of an image using its
histogram. It increases the brightness of a gray scale image which is different from the mean brightness of
the original image. There are various types of Histogram equalization techniques like Histogram
Equalization, Contrast Limited Adaptive Histogram Equalization, Brightness Preserving Bi Histogram
Equalization, Dualistic Sub Image Histogram Equalization, Minimum Mean Brightness Error Bi
Histogram Equalization, Recursive Mean Separate Histogram Equalization and Recursive Sub Image
Histogram Equalization. In this paper, the histogram equalization approach of gray-level images is
extended for colour images. The acquired image is converted into HSV (Hue, Saturation, Value). The
image is then decomposed into two parts by using exposure threshold and then equalized them
independently Over enhancement is also controlled in this method by using clipping threshold. For
measuring the performance of the enhanced image, entropy and contrast are calculated.
Image Enhancement using Guided Filter for under Exposed ImagesDr. Amarjeet Singh
Image enhancement becomes an important step to
improve the quality of image and change in the appearance of
the image in such a way that either a human or a machine can
fetch certain information from the image after a change. Due
to low contrast images it becomes very difficult to get any
information out of it. In today’s digital world of imaging
image enhancement is a very useful in various applications
ranging from electronics printing to recognition. For highly
underexposed region, intensity bin are present in darken
region that’s by such images lacks in saturation and suffers
from low intensity. Power law transformation provides
solution to this problem. It enhances the brightness so as
image at least becomes visible. To modify the intensity level
histogram equalization can be used. In this we can apply
cumulative density function and probabilistic density function
so as to divide the image into sub images.
In proposed approach to provide betterment in
results guided filter has been applied to images after
equalization so that we can get better Entropy rate and
Coefficient of correlation can be improved with previously
available techniques. The guided filter is derived from local
linear model. The guided filter computes the filtering output
by considering the content of guidance image, which can be
the image itself or other targeted image.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
An Efficient Approach for Image Enhancement Based on Image Fusion with Retine...ijsrd.com
Aiming at problems of poor contrast and blurred edges in degraded images, a novel enhancement algorithm is proposed in present research. Image fusion refers to a technique that combines the information from two or more images of a scene into a single fused image.The Algorithm uses Retinex theory and gamma correction to perform a better enhancement of images. The algorithm can efficiently combine the advantages of Retinex and Gamma correction improving both color constancy and intensity of image.
Enhancement of Medical Images using Histogram Based Hybrid TechniqueINFOGAIN PUBLICATION
Digital Image Processing is very important area of research. A number of techniques are available for image enhancement of gray scale images as well as color images. They work very efficiently for enhancement of the gray scale as well as color images. Important techniques namely Histogram Equalization, BBHE, RSWHE, RSWHE (recursion=2, gamma=No), AGCWD (Recursion=0, gamma=0) have been used quite frequently for image enhancement. But there are some shortcomings of the present techniques. The major shortcoming is that while enhancement, the brightness of the image deteriorates quite a lot. So there was need for some technique for image enhancement so that while enhancement was done, the brightness of the images does not go down. To remove this shortcoming, a new hybrid technique namely RESWHE+AGCWD (recursion=2, gamma=0 or 1) was proposed. The results of the proposed technique were compared with the existing techniques. In the present methodology, the brightness did not decrease during image enhancement. So the results and the technique was validated and accepted. The parameters via PSNR, MSE, AMBE etc. are taken for performance evaluation and validation of the proposed technique against the existing techniques which results in better outperform.
Feature Extraction of an Image by Using Adaptive Filtering and Morpological S...IOSR Journals
Abstract: For enhancing an image various enhancement schemes are used which includes gray scale manipulation, filtering and Histogram Equalization, Where Histogram equalization is one of the well known image enhancement technique. It became a popular technique for contrast enhancement because it is simple and effective. The basic idea of Histogram Equalization method is to remap the gray levels of an image. Here using morphological segmentation we can get the segmented image. Morphological reconstruction is used to segment the image. Comparative analysis of different enhancement and segmentation will be carried out. This comparison will be done on the basis of subjective and objective parameters. Subjective parameter is visual quality and objective parameters are Area, Perimeter, Min and Max intensity, Avg Voxel Intensity, Std Dev of Intensity, Eccentricity, Coefficient of skewness, Coefficient of Kurtosis, Median intensity, Mode intensity. Keywords: Histogram Equalization, Segmentation, Morphological Reconstruction .
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.
MODIFIED HISTOGRAM EQUALIZATION FOR IMAGE CONTRAST ENHANCEMENT USING PARTICLE...ijcseit
A novel Modified Histogram Equalization (MHE) technique for contrast enhancement is proposed in this
paper. This technique modifies the probability density function of an image by introducing constraints prior
to the process of histogram equalization (HE). These constraints are formulated using two parameters
which are optimized using swarm intelligence. This technique of contrast enhancement takes control over
the effect of HE so that it enhances the image without causing any loss to its details. A median adjustment
factor is then added to the result to normalize the change in the luminance level after enhancement. This
factor suppresses the effect of luminance change due to the presence of outlier pixels. The outlier pixels of
highly deviated intensities have greater impact in changing the contrast of an image. This approach
provides a convenient and effective way to control the enhancement process, while being adaptive to
various types of images. Experimental results show that the proposed technique gives better results in
terms of Discrete Entropy and SSIM values than the existing histogram-based equalization methods.
A MODIFIED HISTOGRAM BASED FAST ENHANCEMENT ALGORITHMcsandit
The contrast enhancement of medical images has an important role in diseases diagnostic,
specially, cancer cases. Histogram equalization is considered as the most popular algorithm for
contrast enhancement according to its effectiveness and simplicity. In this paper, we present a
modified version of the Histogram Based Fast Enhancement Algorithm. This algorithm
enhances the areas of interest with less complexity. It is applied only to CT head images and its
idea based on treating with the soft tissues and ignoring other details in the image. The
proposed modification make the algorithm is valid for most CT image types with enhanced
results.
An image enhancement method based on gabor filtering in wavelet domain and ad...nooriasukmaningtyas
The images are not always good enough to convey the proper information.
The image may be very bright or very dark sometime or it may be low
contrast or high contrast. Because of these reasons image enhancement plays
important role in digital image processing. In this paper we proposed an
image enhancement technique in which gabor and median filtering is
performed in wavelet domain and adaptive histogram equalization is
performed in spatial domain. Brightness and contrast are the two parameters
Keywords: used for analyzing the performance of the proposed method.
Modified Contrast Enhancement using Laplacian and Gaussians Fusion Techniqueiosrjce
The aim of image fusion is to mix images of a scene captured below totally different illumination. One
image contains most of information from the whole supply images automatically. Contrast enhancement is employed
to enhance the standard of visible image with none introducing unrealistic visual appearances. Fusion technique is
employed for the important applications like medical imaging, microscopic imaging, remote sensing, and laptop
vision and robotics. Contrast enhancement improves the brightness differences within the dark, gray or bright regions
at the expense of the brightness differences within the alternative regions. During this paper methodology of the
contrast enhancement for images that improves the local image contrast by controlling the local image gradient. The
proposed methodology improves the improvement drawback and maximizes the local contrast and global contrast of
an image.
COLOUR IMAGE ENHANCEMENT BASED ON HISTOGRAM EQUALIZATIONecij
Histogram equalization is a nonlinear technique for adjusting the contrast of an image using its histogram. It increases the brightness of a gray scale image which is different from the mean brightness of the original image. There are various types of Histogram equalization techniques like Histogram Equalization, Contrast Limited Adaptive Histogram Equalization, Brightness Preserving Bi Histogram Equalization, Dualistic Sub Image Histogram Equalization, Minimum Mean Brightness Error Bi Histogram Equalization, Recursive Mean Separate Histogram Equalization and Recursive Sub Image Histogram Equalization. In this paper, the histogram equalization approach of gray-level images is extended for colour images. The acquired image is converted into HSV (Hue, Saturation, Value). The image is then decomposed into two parts by using exposure threshold and then equalized them independently Over enhancement is also controlled in this method by using clipping threshold. For
measuring the performance of the enhanced image, entropy and contrast are calculated.
IMAGE ENHANCEMENT IN CASE OF UNEVEN ILLUMINATION USING VARIABLE THRESHOLDING ...ijsrd.com
Uneven illumination always affects the visual quality images which results in poor understanding about the content of the images. There is no accepted universal image enhancement algorithm or specific criteria which can fulfill user needs. The processed image may be very different with the original image in the visual effects, but it also may be similar to the original image [1]. It will be a developing tradition to integrate the advantage of various algorithms to practical application to image enhancements [2]. Zhang et al. [3] presents an adaptive image contrast enhancement method. The proposed method is based on a local gamma correction piloted by histogram analysis. In this paper , to avoid uneven Illuminance image is divided into different segments . It works locally to decrease contrast as if we perform enhancement techniques globally on portions which are already bright then this gives poor results. Enhancement techniques are applied only to those dark portions. We need accurate method that not only enhance the image but also preserve the information.
Contrast enhancement using various statistical operations and neighborhood pr...sipij
Histogram Equalization is a simple and effective contrast enhancement technique. In spite of its popularity
Histogram Equalization still have some limitations –produces artifacts, unnatural images and the local
details are not considered, therefore due to these limitations many other Equalization techniques have been
derived from it with some up gradation. In this proposed method statistics play an important role in image
processing, where statistical operations is applied to the image to get the desired result such as
manipulation of brightness and contrast. Thus, a novel algorithm using statistical operations and
neighborhood processing has been proposed in this paper where the algorithm has proven to be effective in
contrast enhancement based on the theory and experiment.
Interpolation Technique using Non Linear Partial Differential Equation with E...CSCJournals
With the large use of images for the communication, image zooming plays an important role.
Image zooming is the process of enlarging the image with some factor of magnification, where
the factor can be integer or non-integer. Applying zooming algorithm to an image generally results
in aliasing; edge blurring and other artifacts. The main focus of the work presented in this paper is
on the reduction of these artifacts. This paper focuses on reduction of these artifacts and
presents an image zooming algorithm using non-linear fourth order PDE method combined with
edge directed bi-cubic algorithm. The proposed method uses high resolution image obtained from
edge directed bi-cubic interpolation algorithm to construct the zoomed image. This technique
preserves edges and minimizes blurring and staircase effects in the zoomed image. In order to
evaluate image quality obtained after zooming, the objective assessment is performed.
Efficient contrast enhancement using gamma correction with multilevel thresho...eSAT 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.
E FFECTIVE P ROCESSING A ND A NALYSIS OF R ADIOTHERAPY I MAGESsipij
a-Si Electronic Portal Imaging Device (EPID) is an
important tool to verify the location of the radiat
ion
therapy beam with respect to the patient anatomy. B
ut, Electronic Portal Images (EPI) suffer from low
contrast. In order to have better in-treatment imag
es to extract relevant features of the anatomy, ima
ge
processing tools need to be integrated in the Radio
logy systems. The goal of this research work is to
inspect
several image processing techniques for contrast en
hancement of electronic portal images and gauge
parameters like mean, variance, standard deviation,
MSE, RMSE, entropy, PSNR, AMBE, normalised cross
correlation, average difference, structural content
(SC), maximum difference and normalised absolute
error (NAE) to study their visual quality improvem
ent. In addition, by adding salt and pepper noise,
Gaussian noise and motion blur, we calculate error
measurement parameters like Universal Image Quality
(UIQ) index, Enhancement Measurement Error (EME), P
earson Correlation Coefficient, SNR and Mean
Absolute error (MAE). The improved results point ou
t that image processing tools need to be incorporat
ed
into radiology for accurate delivery of dose
PURPOSES: this study aims to perform microcalsification detection by performing image enhancement in mammography image by using transformation of negative image and histogram equalization. METHOD: image mammography with .pgm format changed to. jpg format then processed into negative image result then processed again using histogram equalization. RESULT: the results of the image enhancement process using negative image techniques and equalization histograms are compared and validated with MSE and PSNR on each mammographic image. CONCLUSION: Image enhancement process on mammography image can be done, however there are only some image that have improved quality, this affected by threshold usage, which have important role to get better visualization on mammographic image.
A MODIFIED HISTOGRAM BASED FAST ENHANCEMENT ALGORITHMcscpconf
The contrast enhancement of medical images has an important role in diseases diagnostic,
specially, cancer cases. Histogram equalization is considered as the most popular algorithm for
contrast enhancement according to its effectiveness and simplicity. In this paper, we present a
modified version of the Histogram Based Fast Enhancement Algorithm. This algorithm
enhances the areas of interest with less complexity. It is applied only to CT head images and its
idea based on treating with the soft tissues and ignoring other details in the image. The
proposed modification make the algorithm is valid for most CT image types with enhanced
results.
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TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
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Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
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COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
1. International Journal of Computational Engineering Research||Vol, 04||Issue, 3||
||Issn 2250-3005 || || March || 2014 || Page 25
Bi-Level Weighted Histogram Equalization with Adaptive
Gamma Correction
Jeena Baby1,
V. Karunakaran2
1 PG Student, Department of Computer Science and Engineering, Karunya University
2 Assistant Professor, Department of Computer Science and Engineering, Karunya University
I. INTRODUCTION
Contrast enhancement means improving the visual appearance of the images as well as videos to make
it more satisfactory to the human or machine. Contrast enhancement comes under the image enhancement
techniques. It is used in both image as well as video processing for better visual perception. Several contrast
enhancement techniques are already available. Each technique has got merits and demerits. Histogram
equalization is a very traditional technique where the intensity values of the image are redistributed. Due to
environmental lighting conditions or because of the defects in the photographic devices, images may suffer from
poor contrast. So in order to improve the image quality contrast enhancement is done. Histogram equalization is
a simple and effective technique commonly for contrast enhancement [9].
Generally, the image enhancement techniques are categorized into two: direct [2] and indirect
enhancement techniques. In direct enhancement techniques, the contrast of the image is directly defined by a
definite contrast term [2]. But in indirect enhancement techniques the contrast is improved by redistributing the
intensity values of the image [1]. Histogram equalization [9] techniques can be divided as local and global. In
global, the active range of intensity can be extended using the histogram of the image and thereby increase the
quality. In histogram equalization [9], cumulative distribution function is used to normalize the distribution of
intensities, so that the output image will have uniform distribution of intensities. HE will produce a washed out
effect in the images [9].
In local HE, the histogram as well as the information obtained from the neighborhood pixels are used
for this technique. Here the image is divided into several sub-blocks and then perform HE on each block. The
final image is produced by merging these sub-blocks. The most popular indirect enhancement technique is
called histogram modification techniques [3]. These are easy techniques which can be implemented in a faster
way [1]. A gamma correction method comes under these HM techniques. Here a varying adaptive parameter γ is
used. Transform- based gamma correction [17] is the simplest and it can be derived as
Abstract:
In this paper the bi-level weighted histogram equalization is combined with adaptive gamma correction
method for better brightness preservation and contrast enhancement. The main idea of this method is to
initially divide the input dimmed image into R, G and B components and apply the probability density
function and weighting constraints on each component separately. And finally, an adaptive gamma
correction method is applied to each component and their union produces a brightness preserved and
contrast enhanced output image. The performance of this technique is calculated using Absolute mean
brightness error (AMBE) measure.
Keywords: Contrast enhancement, brightness preservation, histogram equalization, peak signal to
noise ratio, absolute mean brightness error, adaptive gamma correction, probability density function,
cumulative density function.
brightness error
(1)
2. Bi-Level Weighted Histogram Equalization with Adaptive Gammma Correction
||Issn 2250-3005 || || March || 2014 || Page 26
Where l is the intensity of each pixel in the input image and is the maximum intensity. Since a fixed
parameter is used in gamma correction different images will display same changes in intensity. In order to solve
this problem a bi level weighted histogram equalization technique proposed in [16] is used. But this method also
has some problems like over enhancement.
In section 2, related works are described. Section 3 presents the proposed technique. Section 4
discusses the performance metrics to measure the quality of contrast enhanced image. In section 5, results are
discussed and conclusion is given in section 6.
II. RELATED WORKS
Here some previous works related to histogram equalization and adaptive gamma corrections are
discussed. The bi level weighted histogram equalization (BWHE) method [16] segments the input histogram
into two sub histograms based on its mean intensity value. The major problem of this method is the over
enhancement and the introduction of irregularity, called blocking effect.
In segment dependent dynamic multi-histogram equalization [18] the input histogram is divided into n
segments based either on its mean or median and a range is calculated. Histogram equalization is done based on
this range and finally the output image will be normalized. This method is not suitable for color images. Another
method called adaptive gamma correction with weighting distribution combines the traditional HE method and
TGC method [17].
III. PROPOSED METHOD
To solve the problems of the earlier works, a new method has been proposed which combines the bi level HE with
the adaptive gamma correction method [5]. It will produce a high quality image and the computation is also less. This bi
level HE is a technique which combines two methods Weighted Threshold Histogram Equalization (WTHE) [13] and
Brightness preserving Bi-Histogram equalization (BBHE) [3]. The algorithm for the proposed method can be described as
follows in which the equations are derived from [16] and [17]:
1. Input image is separated into R, G and B components. The following steps are applied to each of the
components separately.
2. Compute the probability density function (PDF) of each component.
3. Find the mean pdf of each component.
4. Then apply the constraints described below on each component.
Where , 0.1< <1.0, =0.0001 and is the power factor such that 0.1< <1.0.
5. Find the mean of constrained pdf and then compute the mean error.
6. Add the mean error to constrained pdf .
7. Find the cumulative density function using the .
8. After that find the weighted pdf value using the below equation:
9. Then the modified cdf can be approximated as:
(2)
(3)
(4)
(3)
(5)
(3)
3. Bi-Level Weighted Histogram Equalization with Adaptive Gammma Correction
||Issn 2250-3005 || || March || 2014 || Page 27
Where the sum of can be calculated as:
11. Finally the gamma value is calculated as:
And apply this in the gamma correction formula as:
The AGC method will gradually increase the low intensities and avoid the decrease of the high
intensity. So in order to avoid the undesirable effects produced in the image, a weighting distribution is also
applied [4]. According to [6] and [7] color images are enhanced using HSV color model, where the hue (H) and
saturation (S) is used to represent the color content and value (V) represents the luminance intensity.
In bi-level histogram equalization the computation of constrained pdf helps to control the equalization
of images. After finding out the pdf it is clamped to an upper threshold value and lower threshold value . The
value of comes in the range of 0.1 to 1.0 so that, the pdf’s are clipped with high probabilities. If the value of
is beyond this limit, then over-enhancement occurs. The value of is always less so that, over-enhancement is
very rare. The mean error is calculated in order to recompense the change in the mean luminance level.
IV. IMAGE QUALITY MEASUREMENT
Here two parameters are used to measure the quality of the image. They are: Peak Signal to Noise
Ratio (PSNR) for contrast enhancement measurement [8] and Absolute Mean Brightness Error (AMBE) for
measuring the mean brightness value [8].
4.1. Peak Signal to Noise Ratio
The PSNR [8] is used to compute the peak signal to noise ratio between two images. The ratio is used
as a quality measurement between the original and contrast enhanced image. The higher the PSNR value, the
better the quality of the image.
To compute the PSNR value initially the mean-squared error is calculated using the following equation:
Where M and N are the number of rows and columns in the input images. Then the PSNR can be calculated as
follows:
R is the maximum variation in the input image data type.
4.2. Absolute Mean Brightness Error
The proposed method is trying to preserve the brightness of the images by considering the value of
AMBE [8]. It is calculated as:
Where E[Y] is the mean of contrast enhanced image and E[X] is the mean of original image.
(8)
(7)
(3)
(9)
(10)
(11)
(6)
(3)
4. Bi-Level Weighted Histogram Equalization with Adaptive Gammma Correction
||Issn 2250-3005 || || March || 2014 || Page 28
V. RESULTS AND DISCUSSION
The performance of the proposed method bi-level histogram equalization with adaptive gamma
correction (BWHEAGC) was tested on several color images. The images are shown in Figure 1. To compare the
performance of the proposed method the same images are enhanced using AGCWD [17] method, BWHE and
SDMHE methods. The performance of all these methods are qualitatively measured using PSNR and AMBE.
In this paper 8 dimmed images are used for contrast enhancement and comparison. The contrast
enhancement of images (a) and (e) and their corresponding histogram are shown in Figure 2 and Figure 3
respectively.
Figure 1. Eight dimmed images
(1) (2)
(3) (4)
(5)
Figure 2. Contrast enhancement of image (a), (1) original image, (2) BWHE method, (3) SDMHE method, (4)
AGCWD method, (5) Proposed method
5. Bi-Level Weighted Histogram Equalization with Adaptive Gammma Correction
||Issn 2250-3005 || || March || 2014 || Page 29
(1) (2)
(3) (4)
(5)
Figure 2. Contrast enhancement of image (e), (1) original image, (2) BWHE method, (3) SDMHE method, (4)
AGCWD method, (5) Proposed method
From the above contrast enhanced images it is clear that the BWHE [16] method and the SDMHE [18]
method are producing poor results. In BWHE method over-enhancement is the problem. This problem is solved
in the proposed method by using an adaptive gamma correction method. The SDMHE method is suitable only
for gray level images. The AGCWD [17] method and the proposed method are giving visually acceptable
images. But the output produced by the proposed method is better. The performances of these methods are
measured using two parameters namely, PSNR and AMBE. The PSNR values are given in Table 1 and the
AMBE values are given in Table 2.
Table 1. Comparison of PSNR values
Image Method
BWHE SDMHE AGCWD BWHEAGC
(a) 8.2298 10.2595 14.6281 15.9629
(b) 8.3320 11.1200 13.5193 15.2113
(c) 11.9212 7.8042 20.1488 20.2374
(d) 7.8913 10.0006 15.4067 15.6079
(e) 5.4459 14.9751 15.4850 13.4838
(f) 11.0392 11.1143 15.5627 16.7379
(g) 7.9589 9.1970 17.6459 17.6741
(h) 15.1585 9.4252 17.0107 20.2862
By comparing the PSNR values produced by each of the four methods it is clear that the proposed
method (BWHEAGC) produces better results. Because, from the definition of PSNR it is clear that, higher its
value better will be the image quality. Also from the Table 2, we get the values of AMBE measure which
indicates that the brightness is preserved in the output images. Lower the value of AMBE better will be the
brightness preservation.
6. Bi-Level Weighted Histogram Equalization with Adaptive Gammma Correction
||Issn 2250-3005 || || March || 2014 || Page 30
Table 2. Comparison of AMBE value
Image Method
BWHE SDMHE AGCWD BWHEAGC
(a) 5.8938 0.9116 1.5164 0.4639
(b) 2.3363 9.3737 9.8524 0.1690
(c) 4.2299 0.4463 0.8360 0.0882
(d) 9.6491 3.2908 1.8068 0.5882
(e) 1.0146 0.2724 1.3507 0.6385
(f) 7.0487 6.5929 8.4963 0.3330
(g) 0.1944 8.6451 4.6604 0.4523
(h) 16.5474 3.1738 9.2396 0.4170
VI. CONCLUSION
In this paper, the contrast of dimmed images are enhanced with the help of bi-level weighted HE with
adaptive gamma correction method. This technique is accomplished using two methods, bi-level weighted
histogram equalization where, the pdf and cdf is calculated in a constrained manner and the adaptive gamma
correction method where, a weighting is done on this constrained pdf. Then using the calculated gamma value
the transformation is done. It is computationally simple method and has a high degree of detail preservation.
From the calculated values of PSNR and AMBE measures it is clear that the proposed method has better
brightness preservation and is the best method for contrast enhancement.
REFERENCES
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