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Rate-distortion analysis for light field coding and streaming

SIGNAL PROCESSING-IMAGE COMMUNICATION 2006年第6期21卷 462-475页

作者： Rarnanathan, Prashant Girod, Bernd Stanford Univ Dept Elect Engn Stanford CA 94305 USA

A theoretical framework to analyze the rate-distortion performance of a light field coding and streaming system is proposed. This framework takes into account the statistical properties of the light field images, the accuracy of the geometry information used in disparity compensation, and the prediction dependency structure or transform used to exploit correlation among views. Using this framework, the effect that various parameters have on compression efficiency is studied. The framework reveals that the efficiency gains from more accurate geometry, increase as correlation between images increases. The coding gains due to prediction suggested by the framework match those observed from experimental results. This framework is also used to study the performance of light field streaming by deriving a view-trajectory-dependent rate-distortion function. Simulation results show that the streaming results depend both the prediction structure and the viewing trajectory. For instance, independent coding of images gives the best streaming performance for certain view trajectories. These and other trends described by the simulation results agree qualitatively with actual experimental streaming results. (c) 2006 Elsevier B.V. All rights reserved.

关键词： light fields light field coding light field streaming rate-distortion theory statistica signal processing

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STEERED MIXTURE-OF-EXPERTS FOR light field coding, DEPTH ESTIMATION, AND PROCESSING

STEERED MIXTURE-OF-EXPERTS FOR LIGHT FIELD CODING, DEPTH EST...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： Verhack, Ruben Sikora, Thomas Lange, Lieven Jongebloed, Rolf Van Wallendael, Glenn Lambert, Peter Univ Ghent IMEC IDLab Ghent Belgium Tech Univ Berlin Commun Syst Lab Berlin Germany

ISBN: (纸本)9781509060672

The proposed framework, called Steered Mixture-ofExperts (SMoE), enables a multitude of processing tasks on light fields using a single unified Bayesian model. The underlying assumption is that light field rays are instantiations of a non-linear or non-stationary random process that can be modeled by piecewise stationary processes in the spatial domain. As such, it is modeled as a space-continuous Gaussian Mixture Model. Consequently, the model takes into account different regions of the scene, their edges, and their development along the spatial and disparity dimensions. Applications presented include light field coding, depth estimation, edge detection, segmentation, and view interpolation. The representation is compact, which allows for very efficient compression yielding state-of-the-art coding results for low bit-rates. Furthermore, due to the statistical representation, a vast amount of information can be queried from the model even without having to analyze the pixel values. This allows for "blind" light field processing and classification

关键词： light field coding depth estimation light field representations mixture-of-experts mixture models

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VIEW SYNTHESIS FOR light field coding USING DEPTH ESTIMATION

VIEW SYNTHESIS FOR LIGHT FIELD CODING USING DEPTH ESTIMATION

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IEEE International Conference on Multimedia and Expo (IEEE ICME)

作者： Huang, Xinpeng An, Ping Shan, Liang Ma, Ran Shen, Liquan Shanghai Univ Shanghai Inst Adv Commun & Data Sci Sch Commun & Informat Engn Shanghai 200444 Peoples R China

ISBN: (纸本)9781538617373

light field (LF) image captured by plenoptic camera can record richer scenario information from our world. But a huge number of Sub-Aperture Images (SAIs) from LF image results in great challenges for coding LFI. Therefore, we choose a subset of SAIs as multi-view video, and encode them with their corresponding depth maps using Multi-view Video plus Depth (MVD) structure. Due to lack of depth maps for SAIs, we propose a cost function to determine the depth map for each SAI preliminarily based on horizontal and vertical Epipolar Plane Images (EPI), respectively. Then an SAI-guided depth enhancement algorithm is designed to optimize the estimated depth maps. Since those unselected SAIs have not been encoded but have been synthesized using the specific texture image and depth map, our LF image coding method can naturally achieve bitrates reduction dramatically with a good performance and outperform other algorithms significantly.

关键词： light field coding view synthesis depth estimation depth enhancement

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4D-DCT Hardware Architecture for JPEG Pleno light field coding

4D-DCT Hardware Architecture for JPEG Pleno Light Field Codi...

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IEEE International Conference on Visual Communications and Image Processing (VCIP)

作者： Jahnke, Matheus Goebel, Jones Palomino, Daniel Correa, Guilherme Agostini, Luciano Porto, Marcelo Zatt, Bruno Univ Fed Pelotas Video Technol Res Grp ViTech Grad Program Comp PPGC Pelotas RS Brazil

ISBN: (纸本)9781728180687

This paper presents a 4D-DCT hardware architecture for light field coding according to the JPEG Pleno standard. It is composed of two instances of 2D-DCT engines and a novel 4D Transposition Memory organization. Experimentally-defined fixed-point representation and LSB pruning techniques are employed do reduce hardware area and power dissipation. The proposed architecture operates over 4D-hypercubes of up to 8x8x8x8 samples and reaches performance to process 30 Lytro-like light fields per second dissipating 145.32mW at 825.75MHz. This is the first known 4D-DCT hardware architecture for light field coding and demonstrates the feasibility of such solutions on real-world systems.

关键词： light field coding 4D-DCT Hardware Architecture JPEG Pleno

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The JPEG Pleno light field coding Standard 4D-Transform Mode: How to Design an Efficient 4D-Native Codec

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IEEE ACCESS 2020年 8卷 170807-170829页

作者： De Oliveira Alves, Gustavo De Carvalho, Murilo Bresciani Pagliari, Carla L. Freitas, Pedro Garcia Seidel, Ismael Pereira, Marcio Pinto Vieira, Carla Florentino Schueler Testoni, Vanessa Pereira, Fernando Da Silva, Eduardo A. B. Univ Fed Rio de Janeiro POLI DEL PEECOPPE BR-21941901 Rio de Janeiro Brazil Univ Fed Fluminense CTC TET BR-24220900 Niteroi RJ Brazil IME PGED PEE BR-22290270 Rio De Janeiro Brazil Samsung R&D Inst Brazil SRBR BR-13084791 Campinas Brazil Univ Lisbon Inst Telecomunicacoes Inst Super Tecn P-1049001 Lisbon Portugal

The increasing demand for highly realistic and immersive visual experiences has led to the emergence of richer 3D visual representation models such as light fields, point clouds and meshes. light fields may be modelled as a 2D array of 2D views, corresponding to a large amount of data, which demands for highly efficient coding solutions. Although static light fields are inherently 4D structures, the coding solutions in the literature mostly employ traditional 2D coding tools associated with techniques such as depth-based image rendering to generate a residual, again to be coded using available 2D coding tools. To address the market needs, JPEG has launched the so-called JPEG Pleno standard, which Part 2 is dedicated to light field coding. The JPEG Pleno light field coding standard includes two coding modes, one based on the 4D-DCT, so-called 4D-Transform mode, and another based on depth-based synthesis, so-called 4D-Prediction. The 4D-Transform coding mode standardizes for the first time a 4D-native light field coding solution where the full light field redundancy across the four dimensions is comprehensively exploited, somehow extending to 4D the 2D coding framework adopted decades ago by the popular JPEG Baseline standard. In this context, this paper describes and analyzes in detail the conceptual and algorithmic design process which has led to the creation of the JPEG Pleno light field coding standard 4D-Transform coding mode. This has happened through a sequence of steps involving technical innovation design and integration where increasingly sophisticated coding tools have been combined and improved to maximize the final rate distortion (RD) performance.

关键词： Encoding Transform coding Standards Two dimensional displays Three-dimensional displays Visualization JPEG Pleno standard light field coding 4D-transform mode 4D-DCT

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light field image coding using a residual channel attention network-based view synthesis

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DATA TECHNOLOGIES AND APPLICATIONS 2024年第4期58卷 652-668页

作者： Liu, Faguo Zhang, Qian Yan, Tao Wang, Bin Gao, Ying Hou, Jiaqi Yuan, Feiniu Shanghai Normal Univ Shanghai Peoples R China Putian Univ Putian Peoples R China

Purposelight field images (LFIs) have gained popularity as a technology to increase the field of view (FoV) of plenoptic cameras since they can capture information about light rays with a large FoV. Wide FoV causes light field (LF) data to increase rapidly, which restricts the use of LF imaging in image processing, visual analysis and user interface. Effective LFI coding methods become of paramount importance. This paper aims to eliminate more redundancy by exploring sparsity and correlation in the angular domain of LFIs, as well as mitigate the loss of perceptual quality of LFIs caused by ***/methodology/approachThis work proposes a new efficient LF coding framework. On the coding side, a new sampling scheme and a hierarchical prediction structure are used to eliminate redundancy in the LFI's angular and spatial domains. At the decoding side, high-quality dense LF is reconstructed using a view synthesis method based on the residual channel attention network (RCAN).FindingsIn three different LF datasets, our proposed coding framework not only reduces the transmitted bit rate but also maintains a higher view quality than the current more advanced ***/value(1) A new sampling scheme is designed to synthesize high-quality LFIs while better ensuring LF angular domain sparsity. (2) To further eliminate redundancy in the spatial domain, new ranking schemes and hierarchical prediction structures are designed. (3) A synthetic network based on RCAN and a novel loss function is designed to mitigate the perceptual quality loss due to the coding process.

关键词： light field coding Angular domain View synthesis Residual channel attention network Perceptual quality Prediction structure

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VIEW SYNTHESIS FOR light field coding USING DEPTH ESTIMATION

VIEW SYNTHESIS FOR LIGHT FIELD CODING USING DEPTH ESTIMATION

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IEEE International Conference on Multimedia and Expo

作者： Xinpeng Huang Ping An Liang Shan Ran Ma Liquan Shen Shanghai Institute for Advance Communication and Data Science School of Communication and Information Engineering Shanghai University Shanghai China

关键词： light field coding View synthesis Depth estimation Depth enhancement

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light field Image coding for Efficient Refocusing 12

Light Field Image Coding for Efficient Refocusing

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IEEE 12th International Symposium on Embedded Multicore/Many-core Systems-on-Chip (MCSoC)

作者： Vinh Van Duong Thuong Nguyen Canh Jeon, Byeungwoo Sungkyunkwan Univ Dept Elect & Comp Engn Seoul South Korea

ISBN: (纸本)9781538666890

In video-based light field image coding, researchers often encode a selected subset of sub-aperture images (SAIs). The subset is heuristically selected as 9x9, 11x11, or 13x13 SAIs out of full 15x15 SAIs. Previous work has focused only on the compression efficiency without light field functionality such as refocusing. This paper evaluates the impact of selecting subset of SAIs not only on the compression quality but also on the quality of refocused light field image. A subset of SAIs is proposed to achieve both comparable compression performance and good quality of the refocused images. Compared to full 15x15 SAIs, our method reduces bitrate by 18.4% in viewpoint of compression and at the same time, maintains a good quality of refocused images.

关键词： image compression video compression light field coding video-based refocusing

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Weighted Bi-Prediction for light field Image coding 40

Weighted Bi-Prediction for Light Field Image Coding

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Conference on Applications of Digital Image Processing XL

作者： Conti, Caroline Nunes, Paulo Soares, Luis Ducla Inst Telecommun Av Rovisco Pais 1 P-1049001 Lisbon Portugal IUL ISCTE Av Forcas Armadas P-1649026 Lisbon Portugal

ISBN: (数字)9781510612501

ISBN: (纸本)9781510612501;9781510612495

light field imaging based on a single-tier camera equipped with a microlens array - also known as integral, holoscopic, and plenoptic imaging - has currently risen up as a practical and prospective approach for future visual applications and services. However, successfully deploying actual light field imaging applications and services will require developing adequate coding solutions to efficiently handle the massive amount of data involved in these systems. In this context, self-similarity compensated prediction is a non- local spatial prediction scheme based on block matching that has been shown to achieve high efficiency for light field image coding based on the High Efficiency Video coding (HEVC) standard. As previously shown by the authors, this is possible by simply averaging two predictor blocks that are jointly estimated from a causal search window in the current frame itself, referred to as self-similarity bi-prediction. However, theoretical analyses for motion compensated bi-prediction have suggested that it is still possible to achieve further rate-distortion performance improvements by adaptively estimating the weighting coefficients of the two predictor blocks. Therefore, this paper presents a comprehensive study of the rate-distortion performance for HEVC-based light field image coding when using different sets of weighting coefficients for self-similarity bi-prediction. Experimental results demonstrate that it is possible to extend the previous theoretical conclusions to light field image coding and show that the proposed adaptive weighting coefficient selection leads to up to 5 % of bit savings compared to the previous self-similarity bi-prediction scheme.

关键词： light field coding plenoptic holoscopic HEVC weighted bi-prediction

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light field Image coding for Efficient Refocusing

Light Field Image Coding for Efficient Refocusing

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IEEE International Symposium on Embedded Multicore/Many-core System-on-Chip

作者： Vinh Van Duong Thuong Nguyen Canh Byeungwoo Jeon Department of Electrical and Computer Engineering Sungkyunkwan University

ISBN: (纸本)9781538666906

In video-based light field image coding, researchers often encode a selected subset of sub-aperture images (SAIs). The subset is heuristically selected as 9×9, 11×11, or 13×13 SAIs out of full 15×15 SAIs. Previous work has focused only on the compression efficiency without light field functionality such as refocusing. This paper evaluates the impact of selecting subset of SAIs not only on the compression quality but also on the quality of refocused light field image. A subset of SAIs is proposed to achieve both comparable compression performance and good quality of the refocused images. Compared to full 15×15 SAIs, our method reduces bitrate by 18.4% in viewpoint of compression and at the same time, maintains a good quality of refocused images.

关键词： Image compression Video compression light field coding Video-based Refocusing

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