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Residue-free video coding with pixelwise adaptive spatio-temporal prediction

IET image PROCESSING 2008年第3期2卷 131-138页

作者： Day, M. G. Robinson, J. A. Univ York Dept Elect Visual Syst Lab York YO10 5DD N Yorkshire England

The authors introduce residue-free video coding, in which motion-compensated predictions from surrounding frames and spatial predictions from the current frame are combined adaptively on a pixel-by-pixel basis. The consequence is that residue frames, blocks or regions are never explicitly formed. The authors describe a practical embodiment of a residue-free coder - temporal prediction trees - in which the local adaptation is conditioned frame to frame by a control parameter derived from global motion statistics. Using fixed-block-size motion compensation, the resulting coder is competitive with conventional residue-based compression, and at higher data rates is able to outperform H.264/AVC for high-activity sequences.

关键词： spatiotemporal phenomena global motion statistics video sequence video coding statistical analysis image sequences H.264/AVC Computer vision and image processing techniques image and video coding motion compensation fixed-block-size motion-compensation pixelwise adaptive spatio-temporal prediction residue-free video coding Combinatorial mathematics residue-free coder-temporal prediction tree Other topics in statistics trees (mathematics) video signal processing

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Tabled logic programming based IP matching tool using forced simulation

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IEE PROCEEDINGS-COMPUTERS AND DIGITAL TECHNIQUES 2004年第3期151卷 199-208页

作者： Roop, PS Sowmya, A Ramesh, S Guo, HF Univ Auckland Dept ECE Auckland 1 New Zealand Univ New S Wales Sch CSE Sydney NSW 2052 Australia Indian Inst Technol Dept CSE Bombay 400076 Maharashtra India Univ Nebraska Dept CS Omaha NE 68182 USA

Automatic IP (intellectual property) matching is a key to the reuse of IP cores. A new tabled logic programming-based IP matching algorithm is given that can check whether a given programmable IP can be adapted to match a given specification. When such adaptation is possible, the algorithm also generates a device driver (an interface) to adapt the IP. Though simulation, refinement and bisimulation algorithms exist, they cannot be used to check the adaptability of an IP, which is the essence of reuse. The IP matching algorithm is based on a formal verification technique called forced simulation. A forced simulation matching algorithm is implemented using a tabled logic programming environment, which provides distinct advantages for encoding such an algorithm. The tool has been used to match several specifications to programmable IN, achieving on an average 12 times speedup and 64% reduction in code size in comparison with previously published algorithms.

关键词： low-power dissipation two-stage pipeline architecture system-design consideration data compression VLSI low-power electronics Logic programming hardware complexity logic programming cost effective VLSI design Digital circuit design, modelling and testing low power VLSI design Computer vision and image processing techniques image coding synthesis subband MP3 audio decoding codecs Semiconductor integrated circuit design, layout, modelling and testing Computer-aided logic design reduced memory requirements MPEG layer-3 Electronic engineering computing image and video coding chip design MP3 audio decoder 2.92 mW logic CAD optimised synthesis-subband approach power-consuming component

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General framework of the construction of biorthogonal wavelets based on Bernstein bases: theory analysis and application in image compression

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IET COMPUTER VISION 2011年第1期5卷 50-67页

作者： Yang, X. Shi, Y. Yang, B. Beihang Univ Key Lab Math Informat & Behav Semant Minist Educ Sch Math & Syst Sci Beijing 100191 Peoples R China

The authors present a general framework of the construction of biorthogonal wavelets based on Bernstein bases along with theory analysis and application. The presented framework possesses the largest possible regularity, the required vanishing moments and the passband flatness of frequency response of filters. Based on this concept, the authors establish explicit formulas for filters of biorthogonal wavelets with arbitrary odd lengths. Meanwhile, a new family of parametric filters with symmetry is constructed. The choice of filter bank in wavelet compression is a critical issue that affects image quality. In this study, an optimal model of FIR aiming at image compression is brought forward, and the optimal finite impulse response (FIR) filters can be obtained correspondingly through sequential quadratic programming (SQP) and genetic algorithm (GA). The authors demonstrate the performance of the new family of filters given in this study for image compression with very encouraging results.

关键词： Optimisation techniques theory analysis image quality wavelet transforms biorthogonal wavelet construction genetic algorithm Bernstein base image and video coding Integral transforms band-pass filters genetic algorithms FIR filters passband flatness filter bank frequency response quadratic programming wavelet compression Computer vision and image processing techniques Filtering methods in signal processing image coding sequential quadratic programming FIR filter filter frequency response image compression

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Histogram-based rate-distortion estimation for MPEG-2 video

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IEE PROCEEDINGS-VISION image AND SIGNAL PROCESSING 1999年第4期146卷 198-205页

作者： Hong, SH Kim, SD LG Elect Inc DVA Team DTV Res Lab Seocho Gu Seoul 137724 South Korea Korea Adv Inst Sci & Technol Dept Elect Engn Yusong Gu Taejon 305701 South Korea

A rate-distortion estimation method for MPEG-2 video that enables one to predict the number of bits and the distortion to be generated from an encoded picture at a given quantisation step size, and vice versa is proposed. The estimation method has some outstanding advantages: first, the computational complexity is small because its major operation is just to obtain a histogram or weighted histogram of the DCT coefficients from an input picture, and the final form of the proposed estimation model is simple. Secondly, its results are accurate enough to be applied to practical video coding applications. Simulation results show that the estimation errors for the rate and for the distortion do not exceed 2.5% and 1%, respectively.

关键词： rate distortion theory code standards computational complexity video coding video coding applications telecommunication standards MPEG-2 video data compression quantisation step size transform coding encoded picture input picture weighted histogram video signal processing quantisation (signal) discrete cosine transforms histogram-based rate-distortion estimation Integral transforms in numerical analysis DCT coefficients estimation errors image and video coding simulation results

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Cheating immune visual cryptography scheme

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IET INFORMATION SECURITY 2011年第1期5卷 51-59页

作者： Liu, F. Wu, C. Lin, X. Chinese Acad Sci State Key Lab Informat Secur Inst Software Beijing 100190 Peoples R China Chinese Acad Sci Grad Sch Beijing 100190 Peoples R China Ocean Univ China Qingdao 266100 Peoples R China

Most cheating immune visual cryptography schemes (CIVCS) are based on a traditional visual cryptography scheme (VCS) and are designed to avoid cheating when the secret image of the original VCS is to be recovered. However, all the known CIVCS have some drawbacks. Most usual drawbacks include the following: the scheme needs an online trusted authority, or it requires additional shares for the purpose of verification, or it has to sacrifice the properties by means of pixel expansion and contrast reduction of the original VCS or it can only be based on such VCS with specific access structures. In this study, the authors propose a new CIVCS that can be based on any VCS, including those with a general access structure, and show that their CIVCS can avoid all the above drawbacks. Moreover, their CIVCS does not care about whether the underlying operation is OR or XOR.

关键词： general access structure image resolution online trusted authority authorisation cryptography Computer vision and image processing techniques contrast reduction image and video coding image coding secret image Data security Cryptography pixel expansion cheating immune visual cryptography scheme

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Efficient coding of homogeneous textures using stochastic vector quantisation and linear prediction

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IEE PROCEEDINGS-VISION image AND SIGNAL PROCESSING 1999年第3期146卷 151-158页

作者： Gost, DG Torres, L Univ Politecn Cataluna Dept Signal Theory & Commun Barcelona Spain

Vector quantisation (VQ) has been extensively used as an effective image coding technique. One of the most important steps in the whole process is the design of the codebook. The codebook is generally designed using the LEG algorithm which uses a large training set of empirical data that is statistically representative of the images to be encoded. The LEG algorithm, although quite effective for practical applications, is computationally very expensive and the resulting codebook has to be recalculated each time the type of image to be encoded changes. Stochastic vector quantisation (SVQ) provides an alternative way for the generation of the codebook. In SVQ, a model for the image is computed first, and then the codewords are generated according to this model and not according to some specific training sequence. The SVQ approach presents good coding performance for moderate compression ratios and different type of images. On the other hand, in the context of synthetic and natural hybrid coding (SNHC), there is always need for techniques which may provide very high compression and high quality for homogeneous textures. A new stochastic vector quantisation approach using linear prediction which is able to provide very high compression ratios with graceful degradation for homogeneous textures is presented. Owing to the specific construction of the method, there is no block effect in the synthetised image. Results, implementation details, generation of the bit stream and comparisons with the verification model of MPEG-4 are presented which prove the validity of the approach. The technique has been proposed as a still image coding technique in the SNHC standardisation group of MPEG.

关键词： LBG algorithm still image coding technique VQ stochastic processes linear predictive coding linear prediction Computer vision and image processing techniques vector quantisation stochastic vector quantisation image coding homogeneous textures MPEG-4 codebook design image texture image and video coding SVQ SNHC standardisation high compression ratios synthetic/natural hybrid coding bit stream generation

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Design of a robust and secure digital signature scheme for image authentication over wireless channels

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IET INFORMATION SECURITY 2009年第1期3卷 1-8页

作者： Saad, S. M. Univ Alexandria Dept Informat Technol Inst Grad Studies & Res Alexandria Egypt

The introduction of 3G wireless communication systems, together with the invasive distribution of digital images and the growing concern on their originality triggers an emergent need of authenticating images received by unreliable channels, such as public Internet and wireless networks. To meet this need, a content-based image authentication scheme that is suitable for an insecure network and robust to transmission errors is proposed. The proposed scheme exploits the scalability of a structural digital signature in order to achieve a good trade off between security and image transfer for networked image applications. In this scheme, multi-scale features are used to make digital signatures robust to image degradations and key-dependent parametric wavelet filters are employed to improve the security against forgery attacks. This scheme is also able to distinguish tampering areas in the attacked image. Experimental results show the robustness and validity of the proposed scheme.

关键词： wireless channels multiscale features Filtering methods in signal processing networked image application 3G wireless communication system telecommunication security Computer vision and image processing techniques image and video coding image coding Integral transforms digital signatures secure digital signature scheme wavelet transforms feature extraction key-dependent parametric wavelet filter filtering theory forgery attack wireless channel Data security content-based image authentication scheme 3G mobile communication Mobile radio systems

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CSIS: Compressed sensing-based enhanced-embedding capacity image steganography scheme

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IET image PROCESSING 2021年第9期15卷 1909-1925页

作者： Agrawal, Rohit Ahuja, Kapil Indian Inst Technol Indore Math Data Sci MODS Lab Indore India

image steganography plays a vital role in securing secret data by embedding it in the cover images. Usually, these images are communicated in a compressed format. Existing techniques achieve this but have low embedding capacity. Hence, the goal here is to enhance the embedding capacity while preserving the visual quality of the stego-image. It is also intended to ensure that the scheme is resistant to steganalysis attacks. This paper proposes a compressed sensing image steganography (CSIS) scheme to achieve these goals. In CSIS, the cover image is sparsified block-wise, linear measurements are obtained, and then permissible measurements are selected. Next, the secret data is encrypted, and 2 bits of this encrypted data are embedded into each permissible measurement. For the reconstruction of the stego-image, ADMM and LASSO are used for the resultant optimization problem. Experiments are performed on several standard greyscale images and a colour image. Higher embedding capacity, 1.53 times more compared to the most recent scheme, is achieved. An average of 37.92 dB PSNR value, and average values close to 1 for both the mean SSIM index and the NCC coefficients are obtained, which is considered good. These metrics show that CSIS substantially outperforms existing similar steganography schemes.

关键词： Cryptography image and video coding Optimisation techniques Computer vision and image processing techniques Data security Optimisation techniques

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Low-power context-based adaptive binary arithmetic encoder using an embedded cache

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IET image PROCESSING 2012年第4期6卷 309-317页

作者： Lei, S. -F. Lo, C. -C. Kuo, C. -C. Shieh, M. -D. Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan

H.264/AVC achieves a higher compression ratio than previous standards. However, this standard is also more complex because of the use of methods such as context-based adaptive binary arithmetic coding (CABAC). The high computational complexity of CABAC results in large power consumption. This study presents a systematic analysis for designing a low-power architecture which includes an embedded cache. The analysis provides the mapping scheme between the cache and the main memory where the contexts are stored. The observations for the proposed scheme are based on the statistical correlation between neighbouring blocks for H. 264 coding. The proposed scheme allows the context access operations to hit frequently in the cache, significantly reducing the power consumption. The proposed architecture lowers power consumption by up to 50% compared to designs without embedded cache. An efficient bit-packing method of output bitstream that can be implemented by pipeline structure for high encoding data throughput is also proposed. The throughput of the proposed design is up to 200 Mbins per second for H. 264 main profile.

关键词： Memory circuits CABAC embedded cache bit-packing method data compression H.264 coding image and video coding arithmetic codes low-power architecture Semiconductor storage H.264-AVC binary codes H.264 main profile statistical correlation video coding Computational complexity video signal processing computational complexity correlation theory cache storage high encoding data throughput low-power context-based adaptive binary arithmetic encoder pipeline structure power consumption main memory embedded systems Other topics in statistics higher compression ratio

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Visual sensitivity-based low-bit-rate image compression algorithm

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IET image PROCESSING 2012年第7期6卷 910-918页

作者： Xia, Q. Li, X. Zhuo, L. Lam, K. M. Beijing Univ Technol Signal & Informat Proc Lab Beijing Peoples R China Hong Kong Polytech Univ Dept Elect & Informat Engn Ctr Signal Proc Kowloon Hong Kong Peoples R China

In this study, the authors present a visual sensitivity-based low-bit-rate image compression algorithm. The authors algorithm combines both visual sensitivity and compression techniques so that a higher compression rate, with satisfactory visual quality, can be achieved. In the coding process, the input image is divided into blocks, and each block is classified as an edge block (EB), a textural block (TB) or a flat block (FB). For EBs, which are most important to the subjective quality of decoded images, the standard Joint Photographic Experts Group (JPEG) coding scheme with a tolerant quantisation step is employed so as to restrict the blocking artefacts caused by the quantisation error to an acceptable level. For FBs, a skipping scheme is employed on blocks in the compression process so as to save the bits. The coding of the skip blocks, identified by the skipping scheme, will make reference to the reconstructed regions of the image in the encoding process. Owing to the masking effects of the human visual system on high-frequency textures, standard JPEG compression coding with a greater quantisation step is employed on the down-scaled version of non-skip blocks and TBs. Experimental results show the superior performance of our method in terms of both compression efficiency and visual quality.

关键词： blocking artefacts edge block classification textural block classification visual sensitivity-based low-bit-rate image compression algorithm data compression image reconstruction Joint Photographic Experts Group Computer vision and image processing techniques image and video coding image coding standard JPEG compression coding skipping scheme quantisation (signal) visual quality image classification high-frequency textures image reconstruction regions image texture block codes skip block coding flat block classification quantisation error JPEG coding scheme

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