检索结果-内蒙古大学图书馆

Correlation based universal image/video coding loss recovery

JOURNAL OF VISUAL COMMUNICATION AND image REPRESENTATION 2014年第7期25卷 1507-1515页

作者： Wu, Jinjian Lin, Weisi Shi, Guangming Xiao, Jimin Xidian Univ Sch Elect Engn Xian 710071 Peoples R China Nanyang Technol Univ Sch Comp Engn Singapore 639798 Singapore Tampere Univ Technol Dept Signal Proc FIN-33101 Tampere Finland

coding artifacts are annoying in highly compressed signals. Most of the existing artifact reduction methods are designed for one specific type of artifacts, codecs, and bitrates, which are complex and exclusive for one type of artifact reduction. Since both the compressed image/video and the coding error contain information of the original signal, they are highly correlated. Therefore, we try to recover some lost data based on the correlation between the compressed signal and the coding error, and introduce a novel and universal artifact reduction method. Firstly, according to the spatial correlation among pixels, a pixel-adaptive anisotropic filter is designed to reconstruct the distorted signal. Next, a globally optimal filter is designed to further recover the coding loss. Experimental results demonstrate that within an extensive range of bitrates, the proposed method achieves about 0.8 dB, 0.45 dB, 0.3 dB, and 0.2 dB on average of PSNR improvement for JPEG, MPEG4, H.264/AVC, and HEVC compressed signals, respectively. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Artifact reduction coding loss recovery Correlation Structural self-similarity Global optimization Pixel-adaptive image/video coding Reconstruction

来源：评论

学校读者我要写书评

暂无评论

Spatial-temporal decorrelation for image/video coding

Spatial-temporal decorrelation for image/video coding

引用

29th Picture coding Symposium (PCS)

作者： Wang, Miaohui Ngan, King Ngi Xu, Long Chinese Univ Hong Kong Dept Elect Engn Shatin Hong Kong Peoples R China

ISBN: (纸本)9781457720482

Modern image/video compression techniques greatly help to store and transmit digital images and video data. Discrete wavelet transform is used in JPEG2000 because of its scalability and tolerable degradation. In H.264/AVC, predictive coding is employed to remove spatial redundancy before discrete cosine transform. In this paper, we propose a new encoder structure combining both advantages from JPEG2000 [1] and H.264/AVC [2], which firstly utilizes the proposed spatial transform to decompose a single image into several sub-images and then employs motion compensation to convert the conventional spatial decorrelation into temporal decorrelation. Experimental results show that our proposed method outperforms the state-of-the-art image coding algorithms and achieves better rate-distortion performance.

关键词： Discrete wavelet transform(DWT) Discrete cosine transform(DCT) Spatial-temporal decorrelation image/video coding

来源：评论

学校读者我要写书评

暂无评论

QUANTIZATION TABLE DESIGN REVISITED FOR image/video coding

QUANTIZATION TABLE DESIGN REVISITED FOR IMAGE/VIDEO CODING

引用

20th IEEE International Conference on image Processing (ICIP)

作者： Yang, En-hui Sun, Chang Meng, Jin Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

ISBN: (纸本)9781479923410

Quantization table design is revisited for image/video coding where soft decision quantization (SDQ) is considered. Unlike conventional approaches where quantization table design is bundled with a specific encoding method, we assume optimal SDQ encoding and design a quantization table for the purpose of reconstruction. Under this assumption, we model transform coefficients across different frequencies as independently distributed random sources and apply the Shannon lower bound to approximate the rate distortion function of each source. We then show that a quantization table can be optimized in a way that the resulting distortion complies with certain behavior. Lastly, guided by this new theoretical result, we propose an efficient statistical-model-based algorithm using the Laplacian model to design quantization tables for JPEG encoding. Compared with the state of the art, the proposed algorithm provides an average 0.5 dB gain in PSNR with computational complexity reduced by a factor of more than 2000 when SDQ is off, and a 0.1 dB performance gain with 85% of the complexity reduced when SDQ is on.

关键词： Quantization table soft decision quantization (SDQ) rate distortion optimization Shannon lower bound image/video coding

来源：评论

学校读者我要写书评

暂无评论

A novel image/video coding method based on Compressed Sensing theory

A novel image/video coding method based on Compressed Sensin...

引用

33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Zhang, Yifu Mei, Shunliang Chen, Quqing Chen, Zhibo Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China Thomson Corp Res Beijing 100084 Peoples R China

ISBN: (纸本)9781424414833

Compressed Sensing (CS) has been recently proposed for more efficient signal compression and recovery at theoretical level. This paper proposes a new image/video coding approach combining the CS theory into the traditional discrete cosine transform (DCT) based coding method to achieve better compression efficiency for spatially sparse signal. Furthermore, this new approach is integrated into JPEG and H.264/AVC coding framework as a new coding mode. Rate-distortion optimization is employed for adaptive selection between the new coding mode and the conventional coding modes. Experimental results demonstrated remarkable coding gain for different kinds of natural image/videos by the proposed method.

关键词： compressed sensing discrete cosine transform rate-distortion optimization image/video coding

来源：评论

学校读者我要写书评

暂无评论

Quantization Table Design Revisited for image/video coding

引用

IEEE TRANSACTIONS ON image PROCESSING 2014年第11期23卷 4799-4811页

作者： Yang, En-Hui Sun, Chang Meng, Jin Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

Quantization table design is revisited for image/video coding where soft decision quantization (SDQ) is considered. Unlike conventional approaches, where quantization table design is bundled with a specific encoding method, we assume optimal SDQ encoding and design a quantization table for the purpose of reconstruction. Under this assumption, we model transform coefficients across different frequencies as independently distributed random sources and apply the Shannon lower bound to approximate the rate distortion function of each source. We then show that a quantization table can be optimized in a way that the resulting distortion complies with certain behavior. Guided by this new design principle, we propose an efficient statistical-model-based algorithm using the Laplacian model to design quantization tables for DCT-based image coding. When applied to standard JPEG encoding, it provides more than 1.5-dB performance gain in PSNR, with almost no extra burden on complexity. Compared with the state-of-the-art JPEG quantization table optimizer, the proposed algorithm offers an average 0.5-dB gain in PSNR with computational complexity reduced by a factor of more than 2000 when SDQ is OFF, and a 0.2-dB performance gain or more with 85% of the complexity reduced when SDQ is ON. Significant compression performance improvement is also seen when the algorithm is applied to other image coding systems proposed in the literature.

关键词： Quantization table soft decision quantization rate distortion optimization Shannon lower bound image/video coding

来源：评论

学校读者我要写书评

暂无评论

Quantization table design revisited for image/video coding

Quantization table design revisited for image/video coding

引用

IEEE International Conference on image Processing

作者： En-hui Yang Chang Sun Jin Meng Dept. of Electrical and Computer Engineering University of Waterloo Ontario Canada

ISBN: (纸本)9781479923427

关键词： Quantization table soft decision quantization (SDQ) rate distortion optimization Shannon lower bound image/video coding Quantization Tables Lower bound state of the art rate distortion function Rate distortion Peak signal-to-noise ratio

来源：评论

学校读者我要写书评

暂无评论

image and video coding/Transcoding: A Rate Distortion Approach

Image and Video Coding/Transcoding: A Rate Distortion Approa...

引用

作者： Yu, Xiang University of Waterloo

学位级别：master

Due to the lossy nature of image/video compression and the expensive bandwidth and computation resources in a multimedia system, one of the key design issues for image and video coding/transcoding is to optimize trade-off among distortion, rate, and/or complexity. This thesis studies the application of rate distortion (RD) optimization approaches to image and video coding/transcoding for exploring the best RD performance of a video codec compatible to the newest video coding standard H.264 and for designing computationally efficient down-sampling algorithms with high visual fidelity in the discrete Cosine transform (DCT) domain. RD optimization for video coding in this thesis considers two objectives, i.e., to achieve the best encoding efficiency in terms of minimizing the actual RD cost and to maintain decoding compatibility with the newest video coding standard H.264. By the actual RD cost, we mean a cost based on the final reconstruction error and the entire coding rate. Specifically, an operational RD method is proposed based on a soft decision quantization (SDQ) mechanism, which has its root in a fundamental RD theoretic study on fixed-slope lossy data compression. Using SDQ instead of hard decision quantization, we establish a general framework in which motion prediction, quantization, and entropy coding in a hybrid video coding scheme such as H.264 are jointly designed to minimize the actual RD cost on a frame basis. The proposed framework is applicable to optimize any hybrid video coding scheme, provided that specific algorithms are designed corresponding to coding syntaxes of a given standard codec, so as to maintain compatibility with the standard. Corresponding to the baseline profile syntaxes and the main profile syntaxes of H.264, respectively, we have proposed three RD algorithms?– a graph-based algorithm for SDQ given motion prediction and quantization step sizes, an algorithm for residual coding optimization given motion prediction, and an iterative

关键词： image/video coding Rate Distortion Optimization

来源：评论

学校读者我要写书评

暂无评论

Block-based frequency scalable technique for efficient hierarchical coding

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2006年第7期54卷 2559-2566页

作者： Lee, Jooheung Vijaykrishnan, Narayanan Irwin, Mary Jane Chandramouli, Rajarathnam Penn State Univ Embedded & Mobile Comp Design Ctr University Pk PA 16802 USA Stevens Inst Technol Hoboken NJ 07030 USA

In this paper, we propose a block-based frequency scalable technique for efficient hierarchical coding. The proposed technique divides an image into its multiple resolution versions, based on the spectral properties of discrete cosine transform (DCT) kernels. We present that spectral decomposition, downsampling, and DCT operations are performed effectively over input DCT coefficients of one-dimensional (1-D) and two-dimensional (2-D) signals by using the proposed transform matrices. The proposed image coder is observed to reduce the computational complexity and the memory buffer size with a higher peak signal-to-noise ratio (PSNR), when compared with the traditional hierarchical image coder. In addition, the proposed architecture can preserve compatibility easily with the previous DCT-based image coder.

关键词： discrete cosine transform (DCT) hierarchical coding image/video coding scalable coding

来源：评论

学校读者我要写书评

暂无评论

Fast distortion measurement using chord-length parameterization within the vertex-based rate-distortion optimal shape coding framework

引用

IEEE SIGNAL PROCESSING LETTERS 2007年第2期14卷 121-124页

作者： Sohel, Ferdous Ahmed Karmakar, Gour C. Dooley, Laurence S. Monash Univ Gippsland Sch Informat Technol Gippsland Vic 3842 Australia

Existing vertex-based operational rate-distortion (ORD) optimal shape coding algorithms can use a number of different distortion measurement techniques, including the shortest absolute distance (SAD), the distortion band (DB), the tolerance band (TB), and the accurate distortion measurement technique for shape coding (ADMSC). From a computational time perspective, an N-point contour requires O(N-2) time for DB and TB for both polygon and B-spline-based encoding, while SAD and ADMSC incur O(N) time for polygonal encoding but O(N-2) for B-spline based encoding, thereby rendering the ORD optimal algorithms computationally inefficient. This letter presents a novel distortion measurement strategy based on chord-length parameterization (DMCLP) of a boundary that incurs order O(N) complexity for both polygon and B-spline-based encoding while preserving a comparable rate-distortion performance to the original ORD optimal shape coding algorithms.

关键词： image/video coding transmission

来源：评论

学校读者我要写书评

暂无评论

image Resizing in an Arbitrary Transform Domain

引用

IEICE TRANSACTIONS ON COMMUNICATIONS 2009年第1期E92B卷 346-349页

作者： Kim, Won Ha Oh, Hyung Suk Kyung Hee Univ Fac Informat & Commun Engn Seoul South Korea

This paper develops a methodology for resizing image resolutions in an arbitrary orthogonal block transform domain. To accomplish this, we represent the procedures resizing images in an orthogonal transform domain in the form of matrix multiplications from which the matrix scaling the image resolutions is produce. The experiments showed that the proposed method produces reliable performance without increasing the computational complexity, compared to conventional methods when applied to various transforms.

关键词： image scaling block transform image/video coding H.264/AVC

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：