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Rate-distortion optimised quantisation for direct current coefficients of Wyner-Ziv frame in unidirectional distributed video coding

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IET image PROCESSING 2012年第8期6卷 1064-1074页

作者： Liu, H. Song, B. Liu, J. Qin, H. Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Peoples R China

This study presents a rate-distortion (RD) optimised quantisation algorithm for direct current (DC) coefficients of the Wyner-Ziv (WZ) frames in unidirectional distributed video coding. As the side information (SI) could be viewed as a 'corrupted' version of the original WZ frame, the correlation noise (WZ-SI) can be interpreted as a virtual channel with an error pattern. In this study, the distortion caused by virtual channel errors, besides quantisation errors, is analysed emphatically for unidirectional WZ video coding. In their presented quantisation algorithm, a novel RD model is developed to find out the optimal quantisation step size, in which the quantisation distortion and virtual channel error distortion together with the encoding rate are formulated using the quantisation step size without feedback channels. Then the RD optimal step size for DC coefficients can be solved through minimising the RD cost. In simulations, the comparison of RD performance between their proposed algorithm and the quantisation method used in distributed coding for video services (DISCOVER) is presented. Experimental results show that the proposed RD optimised quantisation for DC coefficients can improve the average peak signal-to-noise ratio of WZ frames by 0.4-1.2 dB for quarter common intermediate format (QCIF) sequences and 0.2-0.4 dB for common intermediate format (CIF), at the expense of increasing the encoding complexity slightly.

关键词： rate-distortion optimised quantisation algorithm quantisation distortion QCIF unidirectional distributed video coding direct current coefficients encoding complexity DISCOVER encoding rate rate-distortion optimised quantisation image and video coding Wyner-Ziv frame DC coefficients distributed coding for video services quantisation (signal) video coding virtual channel distortion side information video signal processing quarter common intermediate format optimal quantisation step size virtual channel error distortion

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image AND video COMPRESSION ALGORITHMS BASED ON RECOVERY TECHNIQUES USING MEAN-FIELD ANNEALING

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PROCEEDINGS OF THE IEEE 1995年第2期83卷 304-316页

作者： OZCELIK, T BRAILEAN, JC KATSAGGELOS, AK NORTHWESTERN UNIV DEPT ELECT ENGN & COMP SCIEVANSTONIL 60208 MOTOROLA INC DIGITAL TECHNOL RES LABSCHAUMBURGIL 60196

image and video coding algorithms have found a number of applications ranging from video telephony on the Public Switched Telephone Networks (PSTN) to HDTV. However, as the bit rate is lowered, most of the existing techniques, as well as current standards, such as JPEG, H. 261, and MPEG-1 produce highly visible degradations in the reconstructed images primarily due to the information loss caused by the quantization process. In this paper, we propose an iterative technique to reduce the unwanted degradations, such as blocking and mosquito artifacts while keeping the necessary detail present in the original image. The proposed technique makes use of a priori information about the original image through a nonstationary Gauss-Markov model. Utilizing this model, a maximum a posteriori (MAP) estimate is obtained iteratively using mean field annealing. The fidelity to the data is preserved by projecting the image onto a constraint set defined by the quantizer at each iteration. The proposed solution represents an implementation of a paradigm we advocate, according to which the decoder is not simply undoing the operations performed by the encoder, but instead it solves an estimation problem based on the available bitstream and any prior knowledge about the source image. The performance of the proposed algorithm was tested on a JPEG, as well as on an H.261-type video codec. It is shown to be effective in removing the coding artifacts present in low bit rate compression.

关键词： image AND video COMPRESSION image and video coding MEAN FIELD ANNEALING

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Analysis of spatial transform motion estimation with overlapped compensation and fractional-pixel accuracy

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IEE PROCEEDINGS-VISION image AND SIGNAL PROCESSING 1999年第6期146卷 339-344页

作者： Lopes, FJP Ghanbari, M Univ Essex Dept Elect Syst Engn Colchester CO4 3SQ Essex England

The authors investigate how the performance of spatial transforms motion estimation can be significantly improved by incorporating overlapped compensation and fractional pixel accuracy. An overlapped spatial transformation (OST) motion model is developed, which successfully addresses the inability of the conventional block matching technique to compensate for complex motion and inside-block motion field discontinuities. Simulation results show that the motion compensated prediction error of this method is reduced by 1.1dB, compared with the conventional overlapped block matching motion estimation, for the same generated motion vectors overhead. To improve the performance, the overlap must be used in both the motion estimation and compensation processes. Further improvement can be obtained using half-pixel precision motion vectors. However, this improvement is comparatively less than the gain of conventional block matching from a half-pixel search.

关键词： prediction theory video coding motion estimation transform coding half-pixel precision motion vectors motion field discontinuities motion compensated prediction error image segmentation motion compensation image matching motion vector overhead video signal processing overlapped compensation Integral transforms in numerical analysis overlapped block matching motion estimation performance overlapped spatial transformation motion model image and video coding fractional-pixel accuracy simulation results spatial transform motion estimation half-pixel search

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Layered coding for Mobile Cloud Gaming Using Scalable Blinn-Phong Lighting

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IEEE TRANSACTIONS ON image PROCESSING 2016年第7期25卷 3112-3125页

作者： Chuah, Seong-Ping Cheung, Ngai-Man Yuen, Chau Singapore Univ Technol & Design Singapore 487372 Singapore Inst Infocomm Res Singapore 138632 Singapore

In a mobile cloud gaming, high-quality, high-frame-rate game images of immense data size need to be delivered to the clients over wireless networks under stringent delay requirement. For good gaming experience, reducing the transmission bit rate of the game images is necessary. Most existing cloud gaming platforms simply employ standard, off-the-shelf video codecs for game image compression. In this paper, we propose the layered coding scheme to reduce transmission bandwidth and latency. We leverage the rendering computation of modern mobile devices to render a low-quality local game image, or the base layer (BL). Instead of sending a high-quality game image, cloud servers can send enhancement layer information, which clients can utilize to improve the quality of the BL. Central to the layered coding scheme is the design of a complexity-scalable BL rendering pipeline that can be executed on a range of power-constrained mobile devices. In this paper, we focus on the lighting stage in modern graphics rendering and propose a method to scale the popular Blinn-Phong lighting for the use in BL rendering. We derive an information-theoretic model on the Blinn-Phong lighting to estimate the rendered image entropy. The analytic model informs the optimal BL rendering design that can lead to maximum bandwidth saving subject to the constraint on the computation capability of the client. We show that the information rate of the enhancement layer could be much less than that of the high-quality game image, while the BL can be generated with only a very small amount of computation. Experiment results suggest that our analytic model is accurate in estimating. For layered coding scheme, up to 84% reduction in bandwidth usage can be achieved by sending the enhancement layer information instead of the original high-quality game images compressed by H.264/AVC.

关键词： Cloud gaming video streaming image and video coding graphic rendering Blinn-Phong lighting

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Hyperspectral image, video compression using sparse tucker tensor decomposition

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IET image PROCESSING 2021年第4期15卷 964-973页

作者： Das, Samiran Indian Inst Technol Kharagpur Adv Technol Dev Ctr Kharagpur W Bengal India

Hyperspectral image and videos provide rich spectral information content, which facilitates accurate classification, unmixing, temporal change detection, and so on. However, with the rapid improvements in technology, the data size has increased many folds. To properly handle the enormous data volume, efficient methods are required to compress the data. This paper proposes a multi-way approach for compression of the hyperspectral image or video sequence. In this approach, a differential representation of the data is first obtained. In the case of hyperspectral images, the difference between consecutive bands is obtained and in case of videos, the difference between consecutive frames is computed. In the next step, a sparse Tucker tensor decomposition is performed and the sparse core tensor obtained. Finally, the core tensor and the corresponding factor matrices are truncated and the data encoded to obtain the compressed version for transmission. The compression method utilises the multi-way structure of the data and hence can be extended for hyperspectral videos. Experimental results on several real data imply that the proposed compression approach obtains better efficiency in terms of compression ratio, signal to noise ratio.

关键词： Instrumentation and techniques for geophysical, hydrospheric and lower atmosphere research Optical, image and video signal processing image and video coding Computer vision and image processing techniques video signal processing

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Statistical morphological skeleton for representing and coding noisy shapes

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IEE PROCEEDINGS-VISION image AND SIGNAL PROCESSING 1999年第2期146卷 85-92页

作者： Foresti, GL Regazzoni, CS Univ Udine Dept Math & Comp Sci I-33100 Udine Italy Univ Genoa Dept Biophys & Elect Engn I-16145 Genoa Italy

A new shape descriptor obtained by skeletonisation of noisy binary images is presented. Skeleton extraction is performed by using an algorithm based on a new class of parametrised binary morphological operators, taking into account statistical aspects. Parameters are adaptively selected during the successive iterations of the skeletonisation operation to regulate the characteristics of the shape descriptor. A probabilistic interpretation of the scheduling strategy used for parameters is proposed by analogy to stochastic optimisation techniques. Skeletonisation results on patterns extracted by a change-detection method in a visual-based surveillance application are reported. Results show the greater robustness of the proposed method as compared with other morphological approaches.

关键词： successive iterations shape representation statistical analysis signal detection skeleton extraction visual-based surveillance application noisy shapes coding parametrised binary morphological operators probability feature extraction robustness noisy binary images image representation Computer vision and image processing techniques image coding surveillance scheduling strategy Interpolation and function approximation (numerical analysis) stochastic optimisation probabilistic interpretation skeletonisation shape descriptor Other topics in statistics image and video coding image thinning iterative methods mathematical morphology statistical morphological skeleton change-detection method

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High-throughput low-cost VLSI architecture for AVC/H.264 CAVLC decoding

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IET image PROCESSING 2010年第2期4卷 81-91页

作者： Lee, G. G. Lo, C. -C. Chen, Y. -C. Lin, H. -Y. Wang, M. -J. Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan

This study develops a low-cost very-large-scale-integration (VLSI) hardware architecture for entropy coding with increased throughput using the statistical properties of context-based adaptive variable-length coding (CAVLC) in AVC/H.264. Statistical analyses show that better symbol length prediction was achieved by breaking the recursive dependency among codewords for the multi-symbol decoder implementation. The proposed CAVLC decoder easily meets the real-time requirements for high definition (HD) (1920 x 1088) applications. The clock speed is only 13 MHz under the best case scenario.

关键词： codewords very-large-scale-integration statistical analysis Codes recursive dependency variable length codes multisymbol decoder implementation image and video coding entropy codes high-throughput low-cost VLSI architecture video coding decoding VLSI context-based adaptive variable-length coding high definition applications symbol length prediction Semiconductor integrated circuits AVC-H.264 CAVLC decoding statistical analyses Other topics in statistics

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Bilateral attention network for semantic segmentation

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IET image PROCESSING 2021年第8期15卷 1607-1616页

作者： Wang, Dongli Li, Nanjun Zhou, Yan Mu, Jinzhen Xiangtan Univ Sch Automat & Elect Informat Xiangtan 411105 Peoples R China Shanghai Aerosp Control Technol Inst Shanghai Peoples R China

Enhancing network feature representation capabilities and reducing the loss of image details have become the focus of semantic segmentation task. This work proposes the bilateral attention network for semantic segmentation. The authors embed two attention modules in the encoder and decoder structures . Specifically, high-level features of the encoder structure integrate all channel maps through dense channel relationships learned by the channel correlation coefficient attention module. The positively correlated channels promote each other, and the negatively correlated channels suppress each other. In the decoder structure, low-level features selectively emphasize the edge detail information in the feature map through the position attention module. The feature expression of semantic segmentation is improved by feature fusion of the two attention modules to obtain more accurate segmentation results . Finally, to verify the effectiveness of the model, the authors conduct experiments on the PASCAL VOC 2012 and Cityscapes scene analysis benchmark data sets and achieve a mean intersection-over-union of 74.92% and 66.63%, respectively.

关键词： image and video coding image recognition Computer vision and image processing techniques

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Deep spectral unmixing framework via 3D denoising convolutional autoencoder

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IET image PROCESSING 2021年第7期15卷 1399-1409页

作者： Jia, Peiyuan Zhang, Miao Shen, Yi Harbin Inst Technol Dept Control Sci & Engn Harbin Peoples R China

Hyperspectral unmixing is an important technique which attempts to acquire pure spectra of distinct substances (endmembers) and estimate fractional abundances from highly mixed pixels. This paper proposed a novel deep network-based framework for unmixing problem. It contains two parts: a three-dimensional convolutional autoencoder for hyperspectral denoising (denoising 3D CAE) which aims to recover data from highly noised input imagery through an unsupervised manner, and a restrictive non-negative sparse autoencoder which extracts endmembers and abundances from the scene simultaneously. The proposed denoising 3D CAE network integrates 3D operations in each layer, which allows manipulating volumetric representation of the image data directly and facilitates hierarchical exploration for latent information. Being trained with corrupted hyperspectral image data, the denoising 3D CAE network has strong capacity of capturing the principle and robust local features in spatial and spectral domains efficiently, and it shows superior performance for image recovery with high noise disturbance. Moreover, a part-based non-negative autoencoder is concatenated, and the l2,1-norm penalty is imposed for sparsity enhancement of the solution. Comparative experiments are conducted both on synthetic and real-world hyperspectral data, which demonstrate the applicability and effectiveness of the proposed unmixing framework.

关键词： Data and information acquisition, processing, storage and dissemination in geophysics Instrumentation and techniques for geophysical, hydrospheric and lower atmosphere research image and video coding image recognition Geophysical techniques and equipment Computer vision and image processing techniques Geography and cartography computing Machine learning (artificial intelligence)

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Application of a novel image moment computation in X-ray and MRI image watermarking

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IET image PROCESSING 2021年第3期15卷 666-682页

作者： Singh, Manoj K. Kumar, Sanoj Ali, Musrrat Saini, Deepika Univ Petr & Energy Studies Dept Math Dehra Dun 248007 Uttarakhand India King Faisal Univ PYD Dept Basic Sci Al Hasa Saudi Arabia Graph Era Deemed Univ Dept Math Dehra Dun Uttarakhand India

Orthogonal polar image moments which are defined over a unit disk, are used often in watermarking applications. One such image moment is polar harmonic Fourier transformation (PHFT). The quality of the extracted watermark depends on the accuracy of the computed image moments. Various methods have already been used for the computation of the moments with varying degrees of accuracy. This study proposes application of a novel image moments computation method which is a synergy of analytic, and numerical techniques, to image watermarking. The computed moment results in a robust watermark extraction. The PHFT have rotation, and scaling invariance property, which allows the watermark to resist various geometric attacks. In addition to the geometric attacks the watermark has the capability to resist various signal processing attacks. The performance of the proposed watermarking scheme is performed with the methods used in recently published articles. The experimental results show that the proposed method has the better performance compared to other techniques, and has better capability to resist various attacks.

关键词： Optical, image and video signal processing image and video coding Biomedical magnetic resonance imaging and spectroscopy X-ray techniques: radiography and computed tomography (biomedical imaging/measurement) Computer vision and image processing techniques Medical magnetic resonance imaging and spectroscopy X-rays and particle beams (medical uses) Patient diagnostic methods and instrumentation Biology and medical computing

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