Justin Varghese - Academia.edu (original) (raw)
Papers by Justin Varghese
The paper proposes a new adaptive weighted median filter for the restoration of impule corrupted ... more The paper proposes a new adaptive weighted median filter for the restoration of impule corrupted digital images by incorporating the limitations posed by Directional Weighted Median Filter (DWMF [4] and the algorithm proposed by Justin et. al [20]-[21]. The algorithm incorporates sixteen directions to identify the presence of edges and to preserve these detected edges while restoring images. The proposed filter uses an adaptive iterative median filter to replace the impulses. The experimental results shows that the proposed filter works better than other competitive filters and is capable of preserving edges.
IET Image Processing, 2020
Periodic noise corrupts digital images during acquisition and transmission stages by adding repet... more Periodic noise corrupts digital images during acquisition and transmission stages by adding repetitive patterns. This study introduces a new adaptive Gaussian notch filter (AGNF) in Fourier transform domain for effectively restoring images contaminated with periodic, quasi-periodic and Moiré pattern noises. Since periodic noises are sinusoidal functions added to the uncorrupted images, Fourier transform of images make these noisy functions to concentrate as easily distinguishable conjugate peaks in frequency domain. The proposed AGNF effectively identifies the noisy peak positions and adaptively quantifies the associated noisy areas by analysing the ratio of averages of frequencies from adaptively varying neighbourhoods. These identified noisy peaks are then diffused by Gaussian notch filter of adaptively varying sizes. The proposed filter ensures maximum diffusion of identified noisy peak areas by maintaining the minimum frequency values from the outputs of overlapping notch filters. Visual and quantitative experimental analysis of the proposed algorithm with mean absolute error, peak signal-tonoise ratio, mean structural similarity index measure and computation time reveals that AGNF is better in restoring images contaminated with periodic noises when compared to other methods.
2006 International Conference on Advanced Computing and Communications, 2006
2006 IFIP International Conference on Wireless and Optical Communications Networks
Abstract A novel contour representation algorithm for binary images which is an extension of the ... more Abstract A novel contour representation algorithm for binary images which is an extension of the conventional chain code is proposed in this paper. The algorithm exploits the features of the conventional chain code when advantageous, is precise and simple with lesser ...
2009 IEEE International Advance Computing Conference, 2009
The paper proposes an efficient quad-tree based filtering algorithm for the restoration of impuls... more The paper proposes an efficient quad-tree based filtering algorithm for the restoration of impulse corrupted digital images. The quad-tree decomposition stage facilitates pixel classification in the impulse detection phase and minimizes miss-classification of signals as impulses by clearly distinguishing the high frequency image details from impulse corrupted pixels. The adaptive restoration phase identifies the most suitable signal restorer from among
2006 Annual IEEE India Conference, 2006
AbstractAn adaptive rank-order based switching Median Filter is proposed in this paper for the r... more AbstractAn adaptive rank-order based switching Median Filter is proposed in this paper for the restoration of digital images corrupted with salt & pepper impulse noise. A more ideal and efficient impulse noise filter, the ARSMF detects all the corrupted pixels even when the ...
proc. of CSI-IEEE First Intnl. Conf. EAIT, 2006
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2016
The paper presents an improved digital image watermarking algorithm by incorporating the discrete... more The paper presents an improved digital image watermarking algorithm by incorporating the discrete Fourier transform (DFT) and singular value decomposition (SVD). The Fourier transformed carrier image is decomposed into four different frequency subbands by the proposed onion peel decomposition (OPD) algorithm and the SVD-based watermarking scheme is applied to attach the transformed watermark in all four carrier subbands. The proposed inverse OPD algorithm together with inverse DFT is utilized to reconstruct the watermarked image from the frequency blocks. The watermark extraction algorithm is simple and it performs the inverse of watermarking process. The experimental analysis on different images shows that the proposed algorithm produces good quality watermarked images. The watermarks extracted from watermarked images inflicted with potential attacks are also of better perception quality than those produced by other prominent algorithms in terms of subjective and objective metrics.
Innovations in Computer Science and Engineering, 2018
Invisible digital image watermarking is one of the most effective and protected methods for obvia... more Invisible digital image watermarking is one of the most effective and protected methods for obviating prohibited copying of digital media. Several research papers have explored watermarking techniques in various domains. In this paper, we carried out experimental analysis to assess the robustness and performance analysis of popular, efficient, secure, and robust invisible digital image watermarking techniques using singular value decompositions (SVD), discrete cosine transform (DCT), discrete wavelet transform (DWT). The experimental and theoretical analysis of different comparative watermarking algorithms in terms of quality of watermarked images and the capability to protect the embedded watermarks in toughest situations demarcates the conclusion of the paper.
Journal of Engineering Research, 2021
Automatic image quality assessment similar to human vision perception is an essential process for... more Automatic image quality assessment similar to human vision perception is an essential process for real-time image processing applications to perform perceptual image assessments for effectively achieving their goals. As no-reference image quality assessment (NR-IQA) schemes perform perceptual assessments of images without any information about their original version, these algorithms suit real-time computer vision techniques because of the non-availability of reference images. Contrast and colorfulness play important roles in determining the quality of color images. By combining many IQA metrics, a number of combined metrics had been devised. This study provides an insight into major NR-IQA methods and their effectiveness in assessing contrast, colorfulness, and overall quality of contrast-degraded images with technical analysis. The effectiveness of top-ranking NR-IQA methods is experimentally assessed with benchmark assessment methods on images from benchmarked databases. The stud...
Journal of Engineering Research, 2021
Digital watermarking provides copyright protection and proof of ownership by inserting watermark ... more Digital watermarking provides copyright protection and proof of ownership by inserting watermark metadata as owner’s identity in digital documents to prevent authenticity and copyright violations. The paper introduces a new hybrid image watermarking scheme by attaching multiple copies of watermarks in carrier image. The new scheme utilizes the advantages of DWT, DFT, DCT and SVD transformations to offer stable resistance in protecting watermark contents from various external attacks. The proposed scheme uses Haar wavelet, Fourier, Onion Peel Decomposition, DCT, zigzag ordering and SVD transforms to decompose the carrier image in to four levels to maintain imperceptibility in the watermarked images. The algorithm attaches replicas of watermark frequency blocks in all frequency components of host image to provide better robustness against external deprivations in watermarked images. The proposed algorithm also provides the increased probability of extracting at least one undamaged rep...
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2016
The paper proposes an adaptive long-range correlation-based filter operator for the restoration o... more The paper proposes an adaptive long-range correlation-based filter operator for the restoration of impulse corrupted digital images. The impulse detection scheme of the proposed algorithm incorporates the local outlier factor (LOF) to avoid the misclassification of uncorrupted pixels as noise. The restoration algorithm uses the local and remote neighborhood of the same size to find structural similarity among pixels for ensuring better replacement of detected impulses. The domain of the remote window is limited around the neighborhood of the impulsive pixel under concern for maintaining image details and thereby producing a high quality restored image. For replacing impulses, the filter uses a reference image and information about the corruption/purity status of the pixels in the image to determine the most correlated uncorrupted pixel from the remote neighborhood. Experimental results show that the proposed filter is capable of producing better results than the comparative filters in terms of subjective and objective metrics.
Arabian Journal for Science and Engineering, 2015
The paper presents an effective nonlinear adaptive switching non-local filter for the restoration... more The paper presents an effective nonlinear adaptive switching non-local filter for the restoration of impulsecorrupted digital images by using distinct impulse detection and correction stages. The correction scheme of the filter adaptively switches between details-preserving non-local mode and signal restoration-based local mode to facilitate high fidelity in the restored image. The non-local filtering operation replaces impulses with a remote pixel that better suits the local image conditions. The algorithm works in this non-local mode only when there are sufficient uncorrupted pixels in the local neighborhood of the corrupted pixel to be replaced. Otherwise, the algorithm replaces impulsive pixels with the median of the uncorrupted pixels from the local neighborhood. Experimental results from various impulse noise levels support the improved performance of the proposed algorithm over other algorithms both subjectively and objectively.
Journal of Engineering Research, 2015
hzUB DCT-SVD …-u nOJ vK …bL F*« WOzU*« W öFK jD WOzd*« ÊU ô« ÍbF ÊUC-bL *** ¨5 s dL * ¨'U u W oeu... more hzUB DCT-SVD …-u nOJ vK …bL F*« WOzU*« W öFK jD WOzd*« ÊU ô« ÍbF ÊUC-bL *** ¨5 s dL * ¨'U u W oeuF ** ¨ w-U 5 U * s b « ÷U-bL *** Ë u U Íu O ***
2013 IEEE International Conference on Computational Intelligence and Computing Research, 2013
A comprehensive analysis of sonar reverberation modeling with respect to Bellhop Compatibility fo... more A comprehensive analysis of sonar reverberation modeling with respect to Bellhop Compatibility for Operational Applications is done in this work. This work focuses on analyzing reverberation models which are designed to be operational oriented. Such models are compatible with the Bellhop propagation model which can be used within the Environment Modeling Manager-EMM. In order to compliment Bellhop model, the Ellis normal mode model and the Harrison closed form expressions could be added to the EMM.
2009 World Congress on Nature & Biologically Inspired Computing (NaBIC), 2009
Abstract A new impulse noise removal algorithm which exhibits improved performance in noise remo... more Abstract A new impulse noise removal algorithm which exhibits improved performance in noise removal by addressing the limitations of the algorithms proposed by KSSrinivasan et. al.[18] and Madhu.et. al.[19] is proposed. The signal restoration scheme of the proposed filter ...
Proceedings - 2006 14th International Conference on Advanced Computing and Communications, ADCOM 2006, 2006
The paper presents an improved median filter for salt & pepper impulse noise removal. The... more The paper presents an improved median filter for salt & pepper impulse noise removal. The computationally efficient filtering technique is implemented as a two pass algorithm involving identification of corrupted pixels that are to be filtered are perfectly detected into a flag image using an ...
Proceedings of the 2008 16th International Conference on Advanced Computing and Communications, ADCOM 2008, 2008
AbstractThe paper puts forward a new filtering algorithm for the restoration of digital images c... more AbstractThe paper puts forward a new filtering algorithm for the restoration of digital images corrupted by impulse noise. The proposed filter includes a Hard-C means clustering stage in the impulse detection phase to facilitate pixel classification and an adaptive impulse ...
Proceedings - 6th Indian Conference on Computer Vision, Graphics and Image Processing, ICVGIP 2008, 2008
The paper proposes a 2D impulse filtering algorithm for the restoration of salt & pep... more The paper proposes a 2D impulse filtering algorithm for the restoration of salt & pepper impulse corrupted digital images. The algorithm incorporates a Hard-C means clustering stage to facilitate pixel classification in the impulse detection phase and an efficient adaptive filtering ...
Proceedings - International Conference on Computational Intelligence and Multimedia Applications, ICCIMA 2007, 2008
The paper proposes a new adaptive 2D spatial filter operator for the restoration of salt &... more The paper proposes a new adaptive 2D spatial filter operator for the restoration of salt & pepper impulse corrupted digital images. The Adaptive Impulse Filter effectively identifies the impulsive positions of the noisy digital image and switches to restore them by an adaptive impulse correction scheme. Experimental results in terms of objective metrics and visual analysis through varied impulse noise
The paper proposes a new adaptive weighted median filter for the restoration of impule corrupted ... more The paper proposes a new adaptive weighted median filter for the restoration of impule corrupted digital images by incorporating the limitations posed by Directional Weighted Median Filter (DWMF [4] and the algorithm proposed by Justin et. al [20]-[21]. The algorithm incorporates sixteen directions to identify the presence of edges and to preserve these detected edges while restoring images. The proposed filter uses an adaptive iterative median filter to replace the impulses. The experimental results shows that the proposed filter works better than other competitive filters and is capable of preserving edges.
IET Image Processing, 2020
Periodic noise corrupts digital images during acquisition and transmission stages by adding repet... more Periodic noise corrupts digital images during acquisition and transmission stages by adding repetitive patterns. This study introduces a new adaptive Gaussian notch filter (AGNF) in Fourier transform domain for effectively restoring images contaminated with periodic, quasi-periodic and Moiré pattern noises. Since periodic noises are sinusoidal functions added to the uncorrupted images, Fourier transform of images make these noisy functions to concentrate as easily distinguishable conjugate peaks in frequency domain. The proposed AGNF effectively identifies the noisy peak positions and adaptively quantifies the associated noisy areas by analysing the ratio of averages of frequencies from adaptively varying neighbourhoods. These identified noisy peaks are then diffused by Gaussian notch filter of adaptively varying sizes. The proposed filter ensures maximum diffusion of identified noisy peak areas by maintaining the minimum frequency values from the outputs of overlapping notch filters. Visual and quantitative experimental analysis of the proposed algorithm with mean absolute error, peak signal-tonoise ratio, mean structural similarity index measure and computation time reveals that AGNF is better in restoring images contaminated with periodic noises when compared to other methods.
2006 International Conference on Advanced Computing and Communications, 2006
2006 IFIP International Conference on Wireless and Optical Communications Networks
Abstract A novel contour representation algorithm for binary images which is an extension of the ... more Abstract A novel contour representation algorithm for binary images which is an extension of the conventional chain code is proposed in this paper. The algorithm exploits the features of the conventional chain code when advantageous, is precise and simple with lesser ...
2009 IEEE International Advance Computing Conference, 2009
The paper proposes an efficient quad-tree based filtering algorithm for the restoration of impuls... more The paper proposes an efficient quad-tree based filtering algorithm for the restoration of impulse corrupted digital images. The quad-tree decomposition stage facilitates pixel classification in the impulse detection phase and minimizes miss-classification of signals as impulses by clearly distinguishing the high frequency image details from impulse corrupted pixels. The adaptive restoration phase identifies the most suitable signal restorer from among
2006 Annual IEEE India Conference, 2006
AbstractAn adaptive rank-order based switching Median Filter is proposed in this paper for the r... more AbstractAn adaptive rank-order based switching Median Filter is proposed in this paper for the restoration of digital images corrupted with salt & pepper impulse noise. A more ideal and efficient impulse noise filter, the ARSMF detects all the corrupted pixels even when the ...
proc. of CSI-IEEE First Intnl. Conf. EAIT, 2006
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2016
The paper presents an improved digital image watermarking algorithm by incorporating the discrete... more The paper presents an improved digital image watermarking algorithm by incorporating the discrete Fourier transform (DFT) and singular value decomposition (SVD). The Fourier transformed carrier image is decomposed into four different frequency subbands by the proposed onion peel decomposition (OPD) algorithm and the SVD-based watermarking scheme is applied to attach the transformed watermark in all four carrier subbands. The proposed inverse OPD algorithm together with inverse DFT is utilized to reconstruct the watermarked image from the frequency blocks. The watermark extraction algorithm is simple and it performs the inverse of watermarking process. The experimental analysis on different images shows that the proposed algorithm produces good quality watermarked images. The watermarks extracted from watermarked images inflicted with potential attacks are also of better perception quality than those produced by other prominent algorithms in terms of subjective and objective metrics.
Innovations in Computer Science and Engineering, 2018
Invisible digital image watermarking is one of the most effective and protected methods for obvia... more Invisible digital image watermarking is one of the most effective and protected methods for obviating prohibited copying of digital media. Several research papers have explored watermarking techniques in various domains. In this paper, we carried out experimental analysis to assess the robustness and performance analysis of popular, efficient, secure, and robust invisible digital image watermarking techniques using singular value decompositions (SVD), discrete cosine transform (DCT), discrete wavelet transform (DWT). The experimental and theoretical analysis of different comparative watermarking algorithms in terms of quality of watermarked images and the capability to protect the embedded watermarks in toughest situations demarcates the conclusion of the paper.
Journal of Engineering Research, 2021
Automatic image quality assessment similar to human vision perception is an essential process for... more Automatic image quality assessment similar to human vision perception is an essential process for real-time image processing applications to perform perceptual image assessments for effectively achieving their goals. As no-reference image quality assessment (NR-IQA) schemes perform perceptual assessments of images without any information about their original version, these algorithms suit real-time computer vision techniques because of the non-availability of reference images. Contrast and colorfulness play important roles in determining the quality of color images. By combining many IQA metrics, a number of combined metrics had been devised. This study provides an insight into major NR-IQA methods and their effectiveness in assessing contrast, colorfulness, and overall quality of contrast-degraded images with technical analysis. The effectiveness of top-ranking NR-IQA methods is experimentally assessed with benchmark assessment methods on images from benchmarked databases. The stud...
Journal of Engineering Research, 2021
Digital watermarking provides copyright protection and proof of ownership by inserting watermark ... more Digital watermarking provides copyright protection and proof of ownership by inserting watermark metadata as owner’s identity in digital documents to prevent authenticity and copyright violations. The paper introduces a new hybrid image watermarking scheme by attaching multiple copies of watermarks in carrier image. The new scheme utilizes the advantages of DWT, DFT, DCT and SVD transformations to offer stable resistance in protecting watermark contents from various external attacks. The proposed scheme uses Haar wavelet, Fourier, Onion Peel Decomposition, DCT, zigzag ordering and SVD transforms to decompose the carrier image in to four levels to maintain imperceptibility in the watermarked images. The algorithm attaches replicas of watermark frequency blocks in all frequency components of host image to provide better robustness against external deprivations in watermarked images. The proposed algorithm also provides the increased probability of extracting at least one undamaged rep...
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2016
The paper proposes an adaptive long-range correlation-based filter operator for the restoration o... more The paper proposes an adaptive long-range correlation-based filter operator for the restoration of impulse corrupted digital images. The impulse detection scheme of the proposed algorithm incorporates the local outlier factor (LOF) to avoid the misclassification of uncorrupted pixels as noise. The restoration algorithm uses the local and remote neighborhood of the same size to find structural similarity among pixels for ensuring better replacement of detected impulses. The domain of the remote window is limited around the neighborhood of the impulsive pixel under concern for maintaining image details and thereby producing a high quality restored image. For replacing impulses, the filter uses a reference image and information about the corruption/purity status of the pixels in the image to determine the most correlated uncorrupted pixel from the remote neighborhood. Experimental results show that the proposed filter is capable of producing better results than the comparative filters in terms of subjective and objective metrics.
Arabian Journal for Science and Engineering, 2015
The paper presents an effective nonlinear adaptive switching non-local filter for the restoration... more The paper presents an effective nonlinear adaptive switching non-local filter for the restoration of impulsecorrupted digital images by using distinct impulse detection and correction stages. The correction scheme of the filter adaptively switches between details-preserving non-local mode and signal restoration-based local mode to facilitate high fidelity in the restored image. The non-local filtering operation replaces impulses with a remote pixel that better suits the local image conditions. The algorithm works in this non-local mode only when there are sufficient uncorrupted pixels in the local neighborhood of the corrupted pixel to be replaced. Otherwise, the algorithm replaces impulsive pixels with the median of the uncorrupted pixels from the local neighborhood. Experimental results from various impulse noise levels support the improved performance of the proposed algorithm over other algorithms both subjectively and objectively.
Journal of Engineering Research, 2015
hzUB DCT-SVD …-u nOJ vK …bL F*« WOzU*« W öFK jD WOzd*« ÊU ô« ÍbF ÊUC-bL *** ¨5 s dL * ¨'U u W oeu... more hzUB DCT-SVD …-u nOJ vK …bL F*« WOzU*« W öFK jD WOzd*« ÊU ô« ÍbF ÊUC-bL *** ¨5 s dL * ¨'U u W oeuF ** ¨ w-U 5 U * s b « ÷U-bL *** Ë u U Íu O ***
2013 IEEE International Conference on Computational Intelligence and Computing Research, 2013
A comprehensive analysis of sonar reverberation modeling with respect to Bellhop Compatibility fo... more A comprehensive analysis of sonar reverberation modeling with respect to Bellhop Compatibility for Operational Applications is done in this work. This work focuses on analyzing reverberation models which are designed to be operational oriented. Such models are compatible with the Bellhop propagation model which can be used within the Environment Modeling Manager-EMM. In order to compliment Bellhop model, the Ellis normal mode model and the Harrison closed form expressions could be added to the EMM.
2009 World Congress on Nature & Biologically Inspired Computing (NaBIC), 2009
Abstract A new impulse noise removal algorithm which exhibits improved performance in noise remo... more Abstract A new impulse noise removal algorithm which exhibits improved performance in noise removal by addressing the limitations of the algorithms proposed by KSSrinivasan et. al.[18] and Madhu.et. al.[19] is proposed. The signal restoration scheme of the proposed filter ...
Proceedings - 2006 14th International Conference on Advanced Computing and Communications, ADCOM 2006, 2006
The paper presents an improved median filter for salt & pepper impulse noise removal. The... more The paper presents an improved median filter for salt & pepper impulse noise removal. The computationally efficient filtering technique is implemented as a two pass algorithm involving identification of corrupted pixels that are to be filtered are perfectly detected into a flag image using an ...
Proceedings of the 2008 16th International Conference on Advanced Computing and Communications, ADCOM 2008, 2008
AbstractThe paper puts forward a new filtering algorithm for the restoration of digital images c... more AbstractThe paper puts forward a new filtering algorithm for the restoration of digital images corrupted by impulse noise. The proposed filter includes a Hard-C means clustering stage in the impulse detection phase to facilitate pixel classification and an adaptive impulse ...
Proceedings - 6th Indian Conference on Computer Vision, Graphics and Image Processing, ICVGIP 2008, 2008
The paper proposes a 2D impulse filtering algorithm for the restoration of salt & pep... more The paper proposes a 2D impulse filtering algorithm for the restoration of salt & pepper impulse corrupted digital images. The algorithm incorporates a Hard-C means clustering stage to facilitate pixel classification in the impulse detection phase and an efficient adaptive filtering ...
Proceedings - International Conference on Computational Intelligence and Multimedia Applications, ICCIMA 2007, 2008
The paper proposes a new adaptive 2D spatial filter operator for the restoration of salt &... more The paper proposes a new adaptive 2D spatial filter operator for the restoration of salt & pepper impulse corrupted digital images. The Adaptive Impulse Filter effectively identifies the impulsive positions of the noisy digital image and switches to restore them by an adaptive impulse correction scheme. Experimental results in terms of objective metrics and visual analysis through varied impulse noise