The importance of underwater wireless optical communication has grown recently for applications o... more The importance of underwater wireless optical communication has grown recently for applications of underwater observation and sea monitoring systems. This communication technology is expected to play a prominent role in investigating climate changes, prediction of natural disasters, and discovery of natural resources, marine biology in lake, sea and ocean environments. Acoustic technology is mostly used for establishing wireless communication link among divers and ships, or sending long range remote signals. Sound waves travel through water faster than in air, receiving very little attenuation. Due to frequency attenuation characteristic of acoustic waves in water, it is difficult to expand its bandwidth. Acoustic approach cannot achieve high data rate, and also portable communication devices are difficult to be designed at lower cost. So the best option is to go for an underwater optical wireless communication system.
2015 Fifth International Conference on Advances in Computing and Communications (ICACC), 2015
The attenuation of standard analog low pass filters for low frequencies is an integer multiple of... more The attenuation of standard analog low pass filters for low frequencies is an integer multiple of -20 dB/dec. In order to attain intermediate values of roll-off factors, such as -10 dB/dec, it would be required to employ a fractional order filter. Fractional order filters have an infinite dimensional representation and thus finite dimensional approximations are computed through the decomposition of fractional order low pass filters into a weighted sum of standard analog one-pole filters. The optimum weights and the positioning of poles are computed using optimization strategies. The acquired weights and poles are laid out into a state space representation as it is a uniform platform for representing time-varying systems, linear systems as well as nonlinear systems. The magnitude and phase response of the fractional order filters are represented through Bode plots.
2015 Fifth International Conference on Advances in Computing and Communications (ICACC), 2015
The effectiveness of an image denoising algorithm depends upon how the signal is represented in i... more The effectiveness of an image denoising algorithm depends upon how the signal is represented in it. A lot of work has been done in the field of image denoising already, but there is a lot of scope for further investigation as well. In this paper, a simple, efficient Patch based and Block based image denoising algorithms, where the noisy image patches are represented using Principal Components and Singular Values is presented. From the conventional Principal Component Analysis (PCA) based denoising algorithm two improved versions of denoising algorithm were developed using patch based and block based Singular Value Decomposition (SVD). These techniques were found to work excellently on images affected by different kinds of noises. A comparison of the three methods using a quantitative analysis in terms of PSNR and RMSE is done.
Sonar images produced due to the coherent nature of scattering phenomenon inherit a multiplicativ... more Sonar images produced due to the coherent nature of scattering phenomenon inherit a multiplicative component called speckle and contain almost homogeneous as well as textured regions with relatively rare edges. Speckle removal is a pre-processing step required in applications like the detection and classification of objects in the sonar image. In this paper computationally efficient Fractional Integral Mask algorithms to remove the speckle noise from sonar images is proposed. RiemannLiouville definition of fractional calculus is used to create Fractional integral masks in eight directions. The use of a mask incorporated with the significant coefficients from the eight directional masks and a single convolution operation required in such case helps in obtaining the computational efficiency. The sonar image heterogeneous patch classification is based on a new proposed naive homogeneity index which depends on the texture strength of the patches and despeckling filters can be adjusted t...
Among the different models investigated for SONAR image denoising, the analysis considers two noi... more Among the different models investigated for SONAR image denoising, the analysis considers two noise models, the signal independent additive noise model and the multiplicative noise model. For the signal-independent additive model, in the transform domain for the denoising a mutiresolution analysis method and the sparsity of the natural sonar images are exploited. For the same model in the spatial domain a side scan sonar image is denoised by Kalman filter-based estimation method. For the multiplicative noise model, in the transform domain a mixed noise removal based on probabilistic patch-based processing is employed and in the spatial domain, the fractional integral mask based method and an unscented Kalman filter based estimation method is adopted.
Digital storage, transmission and manipulation of video signals and still images exhibited a trem... more Digital storage, transmission and manipulation of video signals and still images exhibited a tremendous growth in the last few years, mainly due to the expansion of computer networks and the introduction of multimedia technologies to the information market. Copyright protection techniques are in great demand due to the widespread illegal copying and communication of digital media. One way to protect images against illegal recordings and retransmissions is to embed a signal, called digital signature or copyright label or watermark, that completely characterizes the person who applied it and, therefore, marks it as being his intellectual property. Various watermarking methods have been proposed lately for digital images. Wavelet-based embedding techniques gained a lot of attention since they provide the perfect balance between imperceptibility and robustness. In this project, we introduce an algorithm for hiding the complement of a DNA-encoded watermark data into the 3rd level resolut...
Sonar utilizes underwater sound propagation to explore the presence, location or nature of artifa... more Sonar utilizes underwater sound propagation to explore the presence, location or nature of artifacts in the sea in order to navigate, communicate, or detect other vessels or targets of interest. Acoustics is the best known modality to investigate the water column and sea bed e ciently and accurately. Sonar systems are used for the generation of acoustic images and sea bottom pro ling. The sonar image is a low frequency image with less details and hard to be recognized. Owing to the complexity of the channel and the manners of the sound spreading, the sonar images are not easily interpreted by inexpert human operators, and applications like automatic object detection and recognition can turn out to be rather di cult compared to the optical image. There are many disadvantages to a purely visual interpretation of such images as it is subjective, qualitative and time consuming. Due to the imaging sonar limitations, straight forward image processing is not enough to detect the obstacles ...
Underwater communication plays a significant role in the study of climate change through ocean mo... more Underwater communication plays a significant role in the study of climate change through ocean monitoring and associated sensor networks. It is severely limited when compared to free space communication because water is essentially opaque to electromagnetic radiation except in the visible band. Even in the visible band, light penetrates only a few hundred meters in the clearest waters and much less in turbid waters due to the presence of suspended sediment or high concentrations of marine life. Consequently, acoustic techniques are been used for underwater communication systems which is relatively mature and robust. Acoustic systems are capable of long range communication. But traditional underwater acoustic communications cannot provide high enough data rates to enable monitoring technology. Optical wireless communications, centred around blue-green wavelengths, are being used as an alternative. Here a hybrid design is being introduced using an optical/acoustic link to reduce back scattering of transmitted light.
2015 International Symposium on Ocean Electronics (SYMPOL), 2015
Sonar images are highly affected by signal-dependent multiplicative speckle noise. Denoising is r... more Sonar images are highly affected by signal-dependent multiplicative speckle noise. Denoising is required in sonar images to distinguish a number of different regions by analyzing the image. In this paper, we propose sonar image denoising based on a signal independent additive Gaussian noise model. The sparse representation of the sonar images is exploited in the denoising method. The noisy image, image patches and blocks of patches are denoised using Principal Component Analysis and Singular Value Decomposition methods. Comparison of different methods is done using different non reference image performance evaluation criteria.
The importance of underwater wireless optical communication has grown recently for applications o... more The importance of underwater wireless optical communication has grown recently for applications of underwater observation and sea monitoring systems. This communication technology is expected to play a prominent role in investigating climate changes, prediction of natural disasters, and discovery of natural resources, marine biology in lake, sea and ocean environments. Acoustic technology is mostly used for establishing wireless communication link among divers and ships, or sending long range remote signals. Sound waves travel through water faster than in air, receiving very little attenuation. Due to frequency attenuation characteristic of acoustic waves in water, it is difficult to expand its bandwidth. Acoustic approach cannot achieve high data rate, and also portable communication devices are difficult to be designed at lower cost. So the best option is to go for an underwater optical wireless communication system.
2016 International Conference on Communication and Electronics Systems (ICCES), 2016
This paper uses a Fractional Integral Mask algorithm to remove Poisson noise from medical images.... more This paper uses a Fractional Integral Mask algorithm to remove Poisson noise from medical images. Riemann-Liouville definition of fractional calculus is used to create Fractional integral masks in eight. directions. Two different methods of Mask Combining Technique, CT-1 and CT-2 are introduced for image de-noising. Performance of the algorithm is compared with that of Gaussian smoothing method of noise removal. Results depict that the algorithm with combining technique, CT-2 is better compared to CT-1. Experiments show that the mask size required directly depends on the fractional order. Mask size can be reduced for lower fractional orders thus ensuring the computation complexity reduction for lower orders. The operational range of fractional orders for CT-1 and CT-2 is also estimated. De-noising performance is measured based on visual perception and Peak Signal to Noise Ratio.
Proceedings of Engineering and Technology Innovation
Sonar images are degraded by mixed noise which has an adverse impact on detection and classificat... more Sonar images are degraded by mixed noise which has an adverse impact on detection and classification of underwater objects. Existing denoising methods of sonar images remove either additive noise or multiplicative noise. In this study, the mixed noise in sonar images, the additive Gaussian noise and the multiplicative speckle effect are handled by the data adaptive methods. A patch based denoising is applied in two phases to remove the additive Gaussian and multiplicative speckle noises. In the first phase, the adaptive processing of local patches is used to remove the additive Gaussian noise by exploiting the sonar image local sparsity. The PCA and SVD methods are used for denoising the noisy image patches and blocks of patches. In the second phase, the weighted maximum likelihood denoising of the nonlocal patches reduces the speckle effect by exploiting the non-local similarity in a probability distribution. Experiments on side scan sonar images are conducted and the results show ...
The importance of underwater wireless optical communication has grown recently for applications o... more The importance of underwater wireless optical communication has grown recently for applications of underwater observation and sea monitoring systems. This communication technology is expected to play a prominent role in investigating climate changes, prediction of natural disasters, and discovery of natural resources, marine biology in lake, sea and ocean environments. Acoustic technology is mostly used for establishing wireless communication link among divers and ships, or sending long range remote signals. Sound waves travel through water faster than in air, receiving very little attenuation. Due to frequency attenuation characteristic of acoustic waves in water, it is difficult to expand its bandwidth. Acoustic approach cannot achieve high data rate, and also portable communication devices are difficult to be designed at lower cost. So the best option is to go for an underwater optical wireless communication system.
2015 Fifth International Conference on Advances in Computing and Communications (ICACC), 2015
The attenuation of standard analog low pass filters for low frequencies is an integer multiple of... more The attenuation of standard analog low pass filters for low frequencies is an integer multiple of -20 dB/dec. In order to attain intermediate values of roll-off factors, such as -10 dB/dec, it would be required to employ a fractional order filter. Fractional order filters have an infinite dimensional representation and thus finite dimensional approximations are computed through the decomposition of fractional order low pass filters into a weighted sum of standard analog one-pole filters. The optimum weights and the positioning of poles are computed using optimization strategies. The acquired weights and poles are laid out into a state space representation as it is a uniform platform for representing time-varying systems, linear systems as well as nonlinear systems. The magnitude and phase response of the fractional order filters are represented through Bode plots.
2015 Fifth International Conference on Advances in Computing and Communications (ICACC), 2015
The effectiveness of an image denoising algorithm depends upon how the signal is represented in i... more The effectiveness of an image denoising algorithm depends upon how the signal is represented in it. A lot of work has been done in the field of image denoising already, but there is a lot of scope for further investigation as well. In this paper, a simple, efficient Patch based and Block based image denoising algorithms, where the noisy image patches are represented using Principal Components and Singular Values is presented. From the conventional Principal Component Analysis (PCA) based denoising algorithm two improved versions of denoising algorithm were developed using patch based and block based Singular Value Decomposition (SVD). These techniques were found to work excellently on images affected by different kinds of noises. A comparison of the three methods using a quantitative analysis in terms of PSNR and RMSE is done.
Sonar images produced due to the coherent nature of scattering phenomenon inherit a multiplicativ... more Sonar images produced due to the coherent nature of scattering phenomenon inherit a multiplicative component called speckle and contain almost homogeneous as well as textured regions with relatively rare edges. Speckle removal is a pre-processing step required in applications like the detection and classification of objects in the sonar image. In this paper computationally efficient Fractional Integral Mask algorithms to remove the speckle noise from sonar images is proposed. RiemannLiouville definition of fractional calculus is used to create Fractional integral masks in eight directions. The use of a mask incorporated with the significant coefficients from the eight directional masks and a single convolution operation required in such case helps in obtaining the computational efficiency. The sonar image heterogeneous patch classification is based on a new proposed naive homogeneity index which depends on the texture strength of the patches and despeckling filters can be adjusted t...
Among the different models investigated for SONAR image denoising, the analysis considers two noi... more Among the different models investigated for SONAR image denoising, the analysis considers two noise models, the signal independent additive noise model and the multiplicative noise model. For the signal-independent additive model, in the transform domain for the denoising a mutiresolution analysis method and the sparsity of the natural sonar images are exploited. For the same model in the spatial domain a side scan sonar image is denoised by Kalman filter-based estimation method. For the multiplicative noise model, in the transform domain a mixed noise removal based on probabilistic patch-based processing is employed and in the spatial domain, the fractional integral mask based method and an unscented Kalman filter based estimation method is adopted.
Digital storage, transmission and manipulation of video signals and still images exhibited a trem... more Digital storage, transmission and manipulation of video signals and still images exhibited a tremendous growth in the last few years, mainly due to the expansion of computer networks and the introduction of multimedia technologies to the information market. Copyright protection techniques are in great demand due to the widespread illegal copying and communication of digital media. One way to protect images against illegal recordings and retransmissions is to embed a signal, called digital signature or copyright label or watermark, that completely characterizes the person who applied it and, therefore, marks it as being his intellectual property. Various watermarking methods have been proposed lately for digital images. Wavelet-based embedding techniques gained a lot of attention since they provide the perfect balance between imperceptibility and robustness. In this project, we introduce an algorithm for hiding the complement of a DNA-encoded watermark data into the 3rd level resolut...
Sonar utilizes underwater sound propagation to explore the presence, location or nature of artifa... more Sonar utilizes underwater sound propagation to explore the presence, location or nature of artifacts in the sea in order to navigate, communicate, or detect other vessels or targets of interest. Acoustics is the best known modality to investigate the water column and sea bed e ciently and accurately. Sonar systems are used for the generation of acoustic images and sea bottom pro ling. The sonar image is a low frequency image with less details and hard to be recognized. Owing to the complexity of the channel and the manners of the sound spreading, the sonar images are not easily interpreted by inexpert human operators, and applications like automatic object detection and recognition can turn out to be rather di cult compared to the optical image. There are many disadvantages to a purely visual interpretation of such images as it is subjective, qualitative and time consuming. Due to the imaging sonar limitations, straight forward image processing is not enough to detect the obstacles ...
Underwater communication plays a significant role in the study of climate change through ocean mo... more Underwater communication plays a significant role in the study of climate change through ocean monitoring and associated sensor networks. It is severely limited when compared to free space communication because water is essentially opaque to electromagnetic radiation except in the visible band. Even in the visible band, light penetrates only a few hundred meters in the clearest waters and much less in turbid waters due to the presence of suspended sediment or high concentrations of marine life. Consequently, acoustic techniques are been used for underwater communication systems which is relatively mature and robust. Acoustic systems are capable of long range communication. But traditional underwater acoustic communications cannot provide high enough data rates to enable monitoring technology. Optical wireless communications, centred around blue-green wavelengths, are being used as an alternative. Here a hybrid design is being introduced using an optical/acoustic link to reduce back scattering of transmitted light.
2015 International Symposium on Ocean Electronics (SYMPOL), 2015
Sonar images are highly affected by signal-dependent multiplicative speckle noise. Denoising is r... more Sonar images are highly affected by signal-dependent multiplicative speckle noise. Denoising is required in sonar images to distinguish a number of different regions by analyzing the image. In this paper, we propose sonar image denoising based on a signal independent additive Gaussian noise model. The sparse representation of the sonar images is exploited in the denoising method. The noisy image, image patches and blocks of patches are denoised using Principal Component Analysis and Singular Value Decomposition methods. Comparison of different methods is done using different non reference image performance evaluation criteria.
The importance of underwater wireless optical communication has grown recently for applications o... more The importance of underwater wireless optical communication has grown recently for applications of underwater observation and sea monitoring systems. This communication technology is expected to play a prominent role in investigating climate changes, prediction of natural disasters, and discovery of natural resources, marine biology in lake, sea and ocean environments. Acoustic technology is mostly used for establishing wireless communication link among divers and ships, or sending long range remote signals. Sound waves travel through water faster than in air, receiving very little attenuation. Due to frequency attenuation characteristic of acoustic waves in water, it is difficult to expand its bandwidth. Acoustic approach cannot achieve high data rate, and also portable communication devices are difficult to be designed at lower cost. So the best option is to go for an underwater optical wireless communication system.
2016 International Conference on Communication and Electronics Systems (ICCES), 2016
This paper uses a Fractional Integral Mask algorithm to remove Poisson noise from medical images.... more This paper uses a Fractional Integral Mask algorithm to remove Poisson noise from medical images. Riemann-Liouville definition of fractional calculus is used to create Fractional integral masks in eight. directions. Two different methods of Mask Combining Technique, CT-1 and CT-2 are introduced for image de-noising. Performance of the algorithm is compared with that of Gaussian smoothing method of noise removal. Results depict that the algorithm with combining technique, CT-2 is better compared to CT-1. Experiments show that the mask size required directly depends on the fractional order. Mask size can be reduced for lower fractional orders thus ensuring the computation complexity reduction for lower orders. The operational range of fractional orders for CT-1 and CT-2 is also estimated. De-noising performance is measured based on visual perception and Peak Signal to Noise Ratio.
Proceedings of Engineering and Technology Innovation
Sonar images are degraded by mixed noise which has an adverse impact on detection and classificat... more Sonar images are degraded by mixed noise which has an adverse impact on detection and classification of underwater objects. Existing denoising methods of sonar images remove either additive noise or multiplicative noise. In this study, the mixed noise in sonar images, the additive Gaussian noise and the multiplicative speckle effect are handled by the data adaptive methods. A patch based denoising is applied in two phases to remove the additive Gaussian and multiplicative speckle noises. In the first phase, the adaptive processing of local patches is used to remove the additive Gaussian noise by exploiting the sonar image local sparsity. The PCA and SVD methods are used for denoising the noisy image patches and blocks of patches. In the second phase, the weighted maximum likelihood denoising of the nonlocal patches reduces the speckle effect by exploiting the non-local similarity in a probability distribution. Experiments on side scan sonar images are conducted and the results show ...
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