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Ajouter le résultat dans votre panierA practical design of digital video watermarking in H.264/AVC for content authentication / Po-Chyi Su in Signal processing. Image communication, Vol. 26 N° 8-9 (Octobre 2011)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 413–426
Titre : A practical design of digital video watermarking in H.264/AVC for content authentication Type de document : texte imprimé Auteurs : Po-Chyi Su, Auteur ; Chin-Song Wu, Auteur ; Ing-Fan Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 413–426 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Digital watermark Video authentication H.264/AVC Synchronization Perceptual hash Résumé : In this research, we propose a practical digital video watermarking scheme mainly used for authenticating the H.264/AVC compressed videos to ensure their correct content order. The watermark signals, which represent the serial numbers of video segments, are embedded into nonzero quantization indices of frames to achieve both the effectiveness of watermarking and the compact data size. The human visual characteristics are taken into account to guarantee the imperceptibility of watermark signals and to attain an efficient implementation in H.264/AVC. The issues of synchronized watermark detections are settled by selecting the shot-change frames for calculating the distortion-resilient hash, which helps to determine the watermark sequence. The experimental results demonstrate the feasibility of the proposed scheme as the embedded watermarks can survive the allowed transcoding processes while the edited segments in the tampered video can be located. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000889 [article] A practical design of digital video watermarking in H.264/AVC for content authentication [texte imprimé] / Po-Chyi Su, Auteur ; Chin-Song Wu, Auteur ; Ing-Fan Chen, Auteur . - 2012 . - pp. 413–426.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 413–426
Mots-clés : Digital watermark Video authentication H.264/AVC Synchronization Perceptual hash Résumé : In this research, we propose a practical digital video watermarking scheme mainly used for authenticating the H.264/AVC compressed videos to ensure their correct content order. The watermark signals, which represent the serial numbers of video segments, are embedded into nonzero quantization indices of frames to achieve both the effectiveness of watermarking and the compact data size. The human visual characteristics are taken into account to guarantee the imperceptibility of watermark signals and to attain an efficient implementation in H.264/AVC. The issues of synchronized watermark detections are settled by selecting the shot-change frames for calculating the distortion-resilient hash, which helps to determine the watermark sequence. The experimental results demonstrate the feasibility of the proposed scheme as the embedded watermarks can survive the allowed transcoding processes while the edited segments in the tampered video can be located. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000889
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 427–437
Titre : An integrated visual saliency-based watermarking approach for synchronous image authentication and copyright protection Type de document : texte imprimé Auteurs : Lihua Tian, Auteur ; Nanning Zheng, Auteur ; Jianru Xue, Auteur Année de publication : 2012 Article en page(s) : pp. 427–437 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Watermarking Image authentication Visual saliency Tamper detection and localization Résumé : This paper proposes an integrated visual saliency-based watermarking approach, which can be used for both synchronous image authentication and copyright protection. Firstly, regions of interest (ROIs), which are not in a fixed size and can present the most important information of one image, would be extracted automatically using the proto-object based saliency attention model. Secondly, to resist common signal processing attacks, for each ROI, an improved quantization method is employed to embed the copyright information into its DCT coefficients. Finally, the edge map of one ROI is chosen as the fragile watermark, and is then embedded into the DWT domain of the watermarked image to further resist the tampering attacks. Using ROI-based visual saliency as a bridge, this proposed method can achieve image authentication and copyright protection synchronously, and it can also preserve much more robust information. Experimental results on standard benchmark demonstrate that compared with the state-of-the-art watermarking scheme, the proposed method is more robust to white noise, filtering and JPEG compression attacks. Furthermore, it also shows that the proposed method can effectively detect tamper and locate forgery. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000671 [article] An integrated visual saliency-based watermarking approach for synchronous image authentication and copyright protection [texte imprimé] / Lihua Tian, Auteur ; Nanning Zheng, Auteur ; Jianru Xue, Auteur . - 2012 . - pp. 427–437.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 427–437
Mots-clés : Watermarking Image authentication Visual saliency Tamper detection and localization Résumé : This paper proposes an integrated visual saliency-based watermarking approach, which can be used for both synchronous image authentication and copyright protection. Firstly, regions of interest (ROIs), which are not in a fixed size and can present the most important information of one image, would be extracted automatically using the proto-object based saliency attention model. Secondly, to resist common signal processing attacks, for each ROI, an improved quantization method is employed to embed the copyright information into its DCT coefficients. Finally, the edge map of one ROI is chosen as the fragile watermark, and is then embedded into the DWT domain of the watermarked image to further resist the tampering attacks. Using ROI-based visual saliency as a bridge, this proposed method can achieve image authentication and copyright protection synchronously, and it can also preserve much more robust information. Experimental results on standard benchmark demonstrate that compared with the state-of-the-art watermarking scheme, the proposed method is more robust to white noise, filtering and JPEG compression attacks. Furthermore, it also shows that the proposed method can effectively detect tamper and locate forgery. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000671
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 438–454
Titre : A neighborhood elimination approach for block matching in motion estimation Type de document : texte imprimé Auteurs : Avishek Saha, Auteur ; Jayanta Mukherjee, Auteur ; Shamik Sural, Auteur Année de publication : 2012 Article en page(s) : pp. 438–454 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Video compression Fast motion estimation Search position reduction Neighborhood block elimination Résumé : A new algorithm has been proposed for reducing the number of search locations in block matching based motion estimation. This algorithm uses spatial correlation to eliminate neighboring blocks having low probability of being best match to the candidate block. Existing fast BMAs use a fixed pattern to find the motion vector of a macroblock. On the contrary, the proposed algorithm is independent of any such initially fixed search patterns. The decision to eliminate the neighborhood is taken dynamically based on a preset threshold Th. The extent to which the neighborhood can be eliminated is configured using the shift parameter δ. Thus, reduction in the number of search positions changes dynamically depending on input content. Experiments have been carried out for comparing the performance of the proposed algorithm with other existing BMAs. In addition, an Adaptive Neighborhood Elimination Algorithm (ANEA) has been proposed whereby the Th and δ parameters are updated adaptively. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000683 [article] A neighborhood elimination approach for block matching in motion estimation [texte imprimé] / Avishek Saha, Auteur ; Jayanta Mukherjee, Auteur ; Shamik Sural, Auteur . - 2012 . - pp. 438–454.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 438–454
Mots-clés : Video compression Fast motion estimation Search position reduction Neighborhood block elimination Résumé : A new algorithm has been proposed for reducing the number of search locations in block matching based motion estimation. This algorithm uses spatial correlation to eliminate neighboring blocks having low probability of being best match to the candidate block. Existing fast BMAs use a fixed pattern to find the motion vector of a macroblock. On the contrary, the proposed algorithm is independent of any such initially fixed search patterns. The decision to eliminate the neighborhood is taken dynamically based on a preset threshold Th. The extent to which the neighborhood can be eliminated is configured using the shift parameter δ. Thus, reduction in the number of search positions changes dynamically depending on input content. Experiments have been carried out for comparing the performance of the proposed algorithm with other existing BMAs. In addition, an Adaptive Neighborhood Elimination Algorithm (ANEA) has been proposed whereby the Th and δ parameters are updated adaptively. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000683
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 455–465
Titre : A fast intra prediction mode decision using DCT and quantization for H.264/AVC Type de document : texte imprimé Auteurs : Dae-Yeon Kim, Auteur ; Yung-Lyul Lee, Auteur Année de publication : 2012 Article en page(s) : pp. 455–465 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Video coding Fast mode decision Intra prediction Discrete cosine transform H.264/AVC Résumé : Intra coding is used for reducing the spatial redundancy in video coding. H.264/AVC supports block-based predictions for Intra coding. These Intra predictions also have several directional prediction modes, which significantly improve the Intra coding efficiency, but increase the encoding complexity. In this paper, two fast Intra prediction mode decision algorithms are proposed for H.264/AVC Intra coding. The proposed algorithms select one representative prediction mode or a few representative prediction modes among all intra predictions using the existing DCT and quantization schemes of H.264/AVC, and only the representative modes are used for the Rate Distortion Optimization (RDO) process. The experimental results show that the proposed algorithm 1 and 2 achieve encoding time savings of 53% and 63%, respectively, with negligible loss of Peak Signal-to-Noise Ratio (PSNR). ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000701 [article] A fast intra prediction mode decision using DCT and quantization for H.264/AVC [texte imprimé] / Dae-Yeon Kim, Auteur ; Yung-Lyul Lee, Auteur . - 2012 . - pp. 455–465.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 455–465
Mots-clés : Video coding Fast mode decision Intra prediction Discrete cosine transform H.264/AVC Résumé : Intra coding is used for reducing the spatial redundancy in video coding. H.264/AVC supports block-based predictions for Intra coding. These Intra predictions also have several directional prediction modes, which significantly improve the Intra coding efficiency, but increase the encoding complexity. In this paper, two fast Intra prediction mode decision algorithms are proposed for H.264/AVC Intra coding. The proposed algorithms select one representative prediction mode or a few representative prediction modes among all intra predictions using the existing DCT and quantization schemes of H.264/AVC, and only the representative modes are used for the Rate Distortion Optimization (RDO) process. The experimental results show that the proposed algorithm 1 and 2 achieve encoding time savings of 53% and 63%, respectively, with negligible loss of Peak Signal-to-Noise Ratio (PSNR). ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000701
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 466–481
Titre : Tiny block-size coding for energy-efficient image compression and communication in wireless camera sensor networks Type de document : texte imprimé Auteurs : Cristian Duran-Faundez, Auteur ; Vincent Lecuire, Auteur ; Francis Lepage, Auteur Année de publication : 2012 Article en page(s) : pp. 466–481 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Wireless sensor networks Image communication Image compression Energy conservation Résumé : This article presents a lightweight image compression algorithm explicitly designed for resource-constrained wireless camera sensors, called TiBS (tiny block-size image coding). TiBS operates on blocks of 2×2 pixels (this makes it easy for the end-user to conceal missing blocks due to packet losses) and is based on pixel removal. Furthermore, TiBS is combined with a chaotic pixel mixing scheme to reinforce the robustness of image communication against packet losses. For validation purposes, TiBS as well as a JPEG-like algorithm have been implemented on a real wireless camera sensor composed of a Mica2 mote and a Cyclops imager. The experimental results show that TiBS does not provide high compression ratios, but it enables energy-efficient image communication, even for the source camera node, and even for high packet loss rates. Considering an original 8-bpp grayscale image for instance, the amount of energy consumed by the Cyclops/Mica2 can be reduced by around 60% when the image is compressed using TiBS, compared to the scenario without compression. Moreover, the visual quality of reconstructed images is usually acceptable under packet losses conditions up to 40–50%. In comparison, the JPEG-like algorithm results in clearly more energy consumption than TiBS at similar image quality and, of course, its resilience to packet losses is lower because of the larger size of encoded blocks. Adding redundant packets to the JPEG-encoded data packets may be considered to deal with packet losses, but the energy problem remains. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000890 [article] Tiny block-size coding for energy-efficient image compression and communication in wireless camera sensor networks [texte imprimé] / Cristian Duran-Faundez, Auteur ; Vincent Lecuire, Auteur ; Francis Lepage, Auteur . - 2012 . - pp. 466–481.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 466–481
Mots-clés : Wireless sensor networks Image communication Image compression Energy conservation Résumé : This article presents a lightweight image compression algorithm explicitly designed for resource-constrained wireless camera sensors, called TiBS (tiny block-size image coding). TiBS operates on blocks of 2×2 pixels (this makes it easy for the end-user to conceal missing blocks due to packet losses) and is based on pixel removal. Furthermore, TiBS is combined with a chaotic pixel mixing scheme to reinforce the robustness of image communication against packet losses. For validation purposes, TiBS as well as a JPEG-like algorithm have been implemented on a real wireless camera sensor composed of a Mica2 mote and a Cyclops imager. The experimental results show that TiBS does not provide high compression ratios, but it enables energy-efficient image communication, even for the source camera node, and even for high packet loss rates. Considering an original 8-bpp grayscale image for instance, the amount of energy consumed by the Cyclops/Mica2 can be reduced by around 60% when the image is compressed using TiBS, compared to the scenario without compression. Moreover, the visual quality of reconstructed images is usually acceptable under packet losses conditions up to 40–50%. In comparison, the JPEG-like algorithm results in clearly more energy consumption than TiBS at similar image quality and, of course, its resilience to packet losses is lower because of the larger size of encoded blocks. Adding redundant packets to the JPEG-encoded data packets may be considered to deal with packet losses, but the energy problem remains. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000890
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 482–492
Titre : New pixel based approach for reverse play of MPEG video for streaming system Type de document : texte imprimé Auteurs : Sandeep Kumar, Auteur ; Satish Chand, Auteur Année de publication : 2012 Article en page(s) : pp. 482–492 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Backward play MPEG video Pixel based approach Reverse play VCR functionality Résumé : In macroblock based architecture of MPEG video streaming system with backward playback support, the macroblocks of the frames are divided into two categories: Backward Macroblock (BMB) and Forward/Backward Macroblock (FBMB). The BMB and FBMB are processed differently. This approach reduces the network bandwidth and buffer size requirements. In this paper, we propose a pixel based approach that accesses less data from the server and hence further saves the network bandwidth and buffer requirement. The I- or P-frame (say, frame n−1) is reverse-predicted from the currently decoded frame (i.e., frame n) that is stored in the frame buffer at the client system. Using the motion vector information of frame n, the positions of its various pixels are found in the frame n−1 and their exact values are found using the prediction errors of the frame n by just subtracting them from their values in the frame n. Thus, most of the pixels of frame n−1 are predicted from the frame n. Experimental results show that on an average 93.4% of pixels in the previous I- or P-frame can be reverse-predicted from the current P-frame. The rest 6.6% unpredicted pixels are accumulated in the form of blocks and those blocks are requested from the server. We also propose new Block Identification Algorithms to identify different blocks of unpredicted pixels in an image. They are Maximum Height Minimum Width (MHMW), First Come First Serve (FCFS), Maximum Area (MA), and Biggest Block (BB) algorithms. The server processes the MPEG video stream and returns the desired blocks. We also discuss a FindBlock algorithm for extracting a small block of any frame from the MPEG video stream. Thus, only the motion vectors, prediction errors of frame n, and the unpredicted pixels of the frame n−1 need to be transmitted to the client system. This makes considerable saving in system resources. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000725 [article] New pixel based approach for reverse play of MPEG video for streaming system [texte imprimé] / Sandeep Kumar, Auteur ; Satish Chand, Auteur . - 2012 . - pp. 482–492.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 482–492
Mots-clés : Backward play MPEG video Pixel based approach Reverse play VCR functionality Résumé : In macroblock based architecture of MPEG video streaming system with backward playback support, the macroblocks of the frames are divided into two categories: Backward Macroblock (BMB) and Forward/Backward Macroblock (FBMB). The BMB and FBMB are processed differently. This approach reduces the network bandwidth and buffer size requirements. In this paper, we propose a pixel based approach that accesses less data from the server and hence further saves the network bandwidth and buffer requirement. The I- or P-frame (say, frame n−1) is reverse-predicted from the currently decoded frame (i.e., frame n) that is stored in the frame buffer at the client system. Using the motion vector information of frame n, the positions of its various pixels are found in the frame n−1 and their exact values are found using the prediction errors of the frame n by just subtracting them from their values in the frame n. Thus, most of the pixels of frame n−1 are predicted from the frame n. Experimental results show that on an average 93.4% of pixels in the previous I- or P-frame can be reverse-predicted from the current P-frame. The rest 6.6% unpredicted pixels are accumulated in the form of blocks and those blocks are requested from the server. We also propose new Block Identification Algorithms to identify different blocks of unpredicted pixels in an image. They are Maximum Height Minimum Width (MHMW), First Come First Serve (FCFS), Maximum Area (MA), and Biggest Block (BB) algorithms. The server processes the MPEG video stream and returns the desired blocks. We also discuss a FindBlock algorithm for extracting a small block of any frame from the MPEG video stream. Thus, only the motion vectors, prediction errors of frame n, and the unpredicted pixels of the frame n−1 need to be transmitted to the client system. This makes considerable saving in system resources. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000725
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 493–506
Titre : Detection method and filters for blocking effect reduction of highly compressed images Type de document : texte imprimé Auteurs : Jagroop Singh, Auteur ; Sukhwinder Singh, Auteur ; Dilbag Singh, Auteur Année de publication : 2012 Article en page(s) : pp. 493–506 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Blocking artifacts DCT Image compression MOS PSNR SF Résumé : Image compression plays a pivotal role in minimizing the data size and reduction in transmission costs. Many coding techniques have been developed, but the most effective is the JPEG compression. However, the reconstructed images from JPEG compression produce noticeable image degradations near block boundaries called blocking artifacts, particularly in highly compressed images. A method to detect and reduce these artifacts without smoothing images and without removing perceptual features has been presented in this paper. In this work, a low computational deblocking filter with four modes is proposed, including three frequency-related modes (smooth, non-smooth, and intermediate) and a corner mode for the corner of four blocks. Extensive experiments and comparison with other deblocking methods have been conducted on the basis of PSNR, MSSIM, SF, and MOS to justify the effectiveness of the proposed method. The proposed algorithm keeps the computation lower and achieves better detail preservation and artifact removal performance. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000403 [article] Detection method and filters for blocking effect reduction of highly compressed images [texte imprimé] / Jagroop Singh, Auteur ; Sukhwinder Singh, Auteur ; Dilbag Singh, Auteur . - 2012 . - pp. 493–506.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 493–506
Mots-clés : Blocking artifacts DCT Image compression MOS PSNR SF Résumé : Image compression plays a pivotal role in minimizing the data size and reduction in transmission costs. Many coding techniques have been developed, but the most effective is the JPEG compression. However, the reconstructed images from JPEG compression produce noticeable image degradations near block boundaries called blocking artifacts, particularly in highly compressed images. A method to detect and reduce these artifacts without smoothing images and without removing perceptual features has been presented in this paper. In this work, a low computational deblocking filter with four modes is proposed, including three frequency-related modes (smooth, non-smooth, and intermediate) and a corner mode for the corner of four blocks. Extensive experiments and comparison with other deblocking methods have been conducted on the basis of PSNR, MSSIM, SF, and MOS to justify the effectiveness of the proposed method. The proposed algorithm keeps the computation lower and achieves better detail preservation and artifact removal performance. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000403
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 507–517
Titre : Joint optimization coding for level and map information in H.264/AVC Type de document : texte imprimé Auteurs : Xingsong Hou, Auteur ; Duan Xue, Auteur ; Baiping Jin, Auteur Année de publication : 2012 Article en page(s) : pp. 507–517 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Coefficients pruning Joint optimization coding H.264 Résumé : Since the joint optimization coding for the level and the map information of transformed coefficients has been applied to the image coding successfully, this paper addresses the problem of how to optimize the two parts of information of residual coefficients jointly in the state-of-the-art video coding standard—H.264/AVC. In order to solve this problem, this paper presents a pruning method to zero out residual coefficients, which are not valuable for encoding in rate-distortion optimization (RDO) sense. Furthermore, a joint optimization scheme is presented to combine scalar quantization with this pruning method together to further improve the compression performance of the proposed algorithm. Experiments have been conducted based on the reference encoder JM12.4 of H.264/AVC. Comparative studies show that the proposed joint coding method can achieve a PSNR gain more than 0.5 dB at a certain bit rate, compared with the coding method in the H.264/AVC. Especially, the PSNR gain can reach up to 0.9 dB, or equivalently, 17% bit rate saving can be achieved at some special cases. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000762 [article] Joint optimization coding for level and map information in H.264/AVC [texte imprimé] / Xingsong Hou, Auteur ; Duan Xue, Auteur ; Baiping Jin, Auteur . - 2012 . - pp. 507–517.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 507–517
Mots-clés : Coefficients pruning Joint optimization coding H.264 Résumé : Since the joint optimization coding for the level and the map information of transformed coefficients has been applied to the image coding successfully, this paper addresses the problem of how to optimize the two parts of information of residual coefficients jointly in the state-of-the-art video coding standard—H.264/AVC. In order to solve this problem, this paper presents a pruning method to zero out residual coefficients, which are not valuable for encoding in rate-distortion optimization (RDO) sense. Furthermore, a joint optimization scheme is presented to combine scalar quantization with this pruning method together to further improve the compression performance of the proposed algorithm. Experiments have been conducted based on the reference encoder JM12.4 of H.264/AVC. Comparative studies show that the proposed joint coding method can achieve a PSNR gain more than 0.5 dB at a certain bit rate, compared with the coding method in the H.264/AVC. Especially, the PSNR gain can reach up to 0.9 dB, or equivalently, 17% bit rate saving can be achieved at some special cases. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000762
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 518–533
Titre : Color image demosaicking : An overview Type de document : texte imprimé Auteurs : Daniele Menon, Auteur ; Giancarlo Calvagno, Auteur Année de publication : 2012 Article en page(s) : pp. 518–533 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Demosaicking Bayer pattern Color filter array interpolation Digital cameras Résumé : Demosaicking is the process of reconstructing a full-resolution color image from the sampled data acquired by a digital camera that apply a color filter array to a single sensor. This paper discusses the need of a color filter array and presents a survey of several techniques proposed to demosaicking. A comparison between the different methods is also provided, discussing their performances. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000415 [article] Color image demosaicking : An overview [texte imprimé] / Daniele Menon, Auteur ; Giancarlo Calvagno, Auteur . - 2012 . - pp. 518–533.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 518–533
Mots-clés : Demosaicking Bayer pattern Color filter array interpolation Digital cameras Résumé : Demosaicking is the process of reconstructing a full-resolution color image from the sampled data acquired by a digital camera that apply a color filter array to a single sensor. This paper discusses the need of a color filter array and presents a survey of several techniques proposed to demosaicking. A comparison between the different methods is also provided, discussing their performances. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000415
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 534–549
Titre : Edge-region information measure based on deformed and displaced pixel for image quality assessment Type de document : texte imprimé Auteurs : Zianou Ahmed Seghir, Auteur ; Fella Hachouf, Auteur Année de publication : 2012 Article en page(s) : pp. 534–549 Note générale : Electronique Langues : Anglais (eng) Mots-clés : IQA Difference mean opinion score (DMOS) Displaced pixel Distorted pixel Résumé : Image quality depends on many factors, such as the initial capture system and its image processing, compression, transmission, the output device, media and associated viewing conditions. The goal of quality assessment research is to design measures that can automatically evaluate the quality of images in a perceptually consistent manner. This paper proposes a new measure for image quality assessment (IQA), which supplies more flexibility than previous methods in using the pixel displacement in the assessment. First, the distorted and original images are divided into overlapped 11×11 blocks, and secondly, we calculated distorted pixels and displacement, and then, visual regions of interest and edge information are computed, which can be used to compute the global error. Experimental comparisons show the efficiency of the proposed method. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000695 [article] Edge-region information measure based on deformed and displaced pixel for image quality assessment [texte imprimé] / Zianou Ahmed Seghir, Auteur ; Fella Hachouf, Auteur . - 2012 . - pp. 534–549.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 534–549
Mots-clés : IQA Difference mean opinion score (DMOS) Displaced pixel Distorted pixel Résumé : Image quality depends on many factors, such as the initial capture system and its image processing, compression, transmission, the output device, media and associated viewing conditions. The goal of quality assessment research is to design measures that can automatically evaluate the quality of images in a perceptually consistent manner. This paper proposes a new measure for image quality assessment (IQA), which supplies more flexibility than previous methods in using the pixel displacement in the assessment. First, the distorted and original images are divided into overlapped 11×11 blocks, and secondly, we calculated distorted pixels and displacement, and then, visual regions of interest and edge information are computed, which can be used to compute the global error. Experimental comparisons show the efficiency of the proposed method. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000695
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 550–566
Titre : Smooth adaptive fitting of 3D face model for the estimation of rigid and nonrigid facial motion in video sequences Type de document : texte imprimé Auteurs : Yunshu Hou, Auteur ; Ping Fan, Auteur ; Ilse Ravyse, Auteur Année de publication : 2012 Article en page(s) : pp. 550–566 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Facial analysis Model-based tracking Motion-smoothness constraints Résumé : We propose a 3D wireframe face model alignment for the task of simultaneously tracking of rigid head motion and nonrigid facial expressions in video sequences. The system integrates two levels: (i) at the low level, automatic and accurate location of facial features are obtained via a cascaded optimization algorithm of a 2D shape model, (ii) at the high level, we recover, via minimizing an energy function, the optimal motion parameters of the 3D model, namely the 3D rigid motion parameters and seven nonrigid animation (Action Unit) parameters. In this latter inference, a 3D face shape model (Candide) is automatically fitted to the image sequence via a least squares minimization of the energy, defined as the residual between the projected 3D wireframe model and the 2D shape model, meanwhile imposing temporal and spatial motion-smoothness constraints over the 3D model points. Our proposed system tackles many disadvantages of the optimization and training associated with active appearance models. Extensive fitting and tracking experiments demonstrate the feasibility, accuracy and effectiveness of the developed methods. Qualitative and quantitative performance of the proposed system on several facial sequences, indicate its potential usefulness for multimedia applications, as well as facial expression analysis. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000579 [article] Smooth adaptive fitting of 3D face model for the estimation of rigid and nonrigid facial motion in video sequences [texte imprimé] / Yunshu Hou, Auteur ; Ping Fan, Auteur ; Ilse Ravyse, Auteur . - 2012 . - pp. 550–566.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 550–566
Mots-clés : Facial analysis Model-based tracking Motion-smoothness constraints Résumé : We propose a 3D wireframe face model alignment for the task of simultaneously tracking of rigid head motion and nonrigid facial expressions in video sequences. The system integrates two levels: (i) at the low level, automatic and accurate location of facial features are obtained via a cascaded optimization algorithm of a 2D shape model, (ii) at the high level, we recover, via minimizing an energy function, the optimal motion parameters of the 3D model, namely the 3D rigid motion parameters and seven nonrigid animation (Action Unit) parameters. In this latter inference, a 3D face shape model (Candide) is automatically fitted to the image sequence via a least squares minimization of the energy, defined as the residual between the projected 3D wireframe model and the 2D shape model, meanwhile imposing temporal and spatial motion-smoothness constraints over the 3D model points. Our proposed system tackles many disadvantages of the optimization and training associated with active appearance models. Extensive fitting and tracking experiments demonstrate the feasibility, accuracy and effectiveness of the developed methods. Qualitative and quantitative performance of the proposed system on several facial sequences, indicate its potential usefulness for multimedia applications, as well as facial expression analysis. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000579
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 567–576
Titre : How quantization based schemes can be used in image steganographic context Type de document : texte imprimé Auteurs : Braci, Sofiane, Auteur ; Claude Delpha, Auteur ; Rémy Boyer, Auteur Année de publication : 2012 Article en page(s) : pp. 567–576 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Image processing for watermarking and steganography Costa scheme Spread transform Résumé : The quantization based embedding systems are widely used in the information hiding applications, thanks to their efficiency and simplicity. Moreover, they are known to be insecure in steganography context according to the Cachins' security definition because they distort the stego-signal probability density function. In this paper, we show that using the well-known spread transform (ST) combining with quantization based embedding systems provides an ε-secure stego-system in the sense of Cachin's security definition. In other words, we show theoretically that this system preserves, in the sense of the relative entropy, the probability density function of the stego-signal as long as the ratio between the quantization step and the square root of the spreading factor is small. This highlights the fundamental tradeoff between these two quantities. Our theoretical conclusions are validated and illustrated on real images. Finally, a comparison with the Solanki et al. blind steganographic scheme is given. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000907 [article] How quantization based schemes can be used in image steganographic context [texte imprimé] / Braci, Sofiane, Auteur ; Claude Delpha, Auteur ; Rémy Boyer, Auteur . - 2012 . - pp. 567–576.
Electronique
Langues : Anglais (eng)
in Signal processing. Image communication > Vol. 26 N° 8-9 (Octobre 2011) . - pp. 567–576
Mots-clés : Image processing for watermarking and steganography Costa scheme Spread transform Résumé : The quantization based embedding systems are widely used in the information hiding applications, thanks to their efficiency and simplicity. Moreover, they are known to be insecure in steganography context according to the Cachins' security definition because they distort the stego-signal probability density function. In this paper, we show that using the well-known spread transform (ST) combining with quantization based embedding systems provides an ε-secure stego-system in the sense of Cachin's security definition. In other words, we show theoretically that this system preserves, in the sense of the relative entropy, the probability density function of the stego-signal as long as the ratio between the quantization step and the square root of the spreading factor is small. This highlights the fundamental tradeoff between these two quantities. Our theoretical conclusions are validated and illustrated on real images. Finally, a comparison with the Solanki et al. blind steganographic scheme is given. ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596511000907
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