JPEG2000图像压缩编码系统及其关键技术

介绍了JPEG2000标准的特点及应用场合，阐述了JPEG2000图像编码系统的实现过程，对其中采用的基本算法和关键技术进行了描述。     

JPEG2000图像压缩标准及其关键算法

JPEG2000是为适应不断发展的图像压缩应用而出现的新的静止图像压缩标准。阐述了JPEG2000图像编码系统的实现过程，对其中采用的基本算法和关键技术进行了描述，介绍了这一新标准的特点及应用场合，并对其性能进行了分析。     

基于ADV202的JPEG2000实时图像解压缩系统

JPEG2000是ISO/ITU-T既推出JPEG静态图像压缩标准后推出的有一种高效能图像压缩标准。JPEG2000相比JPEG压缩算法,具有更高的压缩比,更高的图像压缩质量,其特有的具有图像多分辨率的特点,使其适合多种应用场合。在对JPEG2000压缩标准作了简介后,针对ADV202芯片提出了JPEG2000压缩解压缩实现方案。该实现方案,具有体积小、功耗低、成本低、调试简单的特点。     

JPEG2000标准中压缩算法原理分析

随着多媒体技术应用的不断增加,人们对图像压缩技术也提出了更高的要求,JPEG2000正是为适应不断发展的图像压缩应用而出现的新的静止图像压缩编码标准。文章从JPEG2000的目标和基本特征出发,阐述了JPEG2000图像编码采用的基本压缩算法,并对这一新标准的特点及其优缺点进行了简单介绍。     

国外动态

JPEG2000使NHK的Hi-:Vision HDTV得到增强 日本广播机构NHK将ADI公司的JPEG2000图像压缩芯片包含进其最新的Hi-Vision HDTV电视机中。NHK的科技研究实验室(STRL)开发了单个实时编/解码板,它以JPEG2000标准为基础,ADI公司的JPEG2000芯片使JPEG2000标准成为可能。     

新一代静止图像编码系统-JPEG2000

JPEG2000是最新制定的静止图像编码国际标准，JPEG2000不仅提供的率失真性能和主观图像质量优于原JPEG标准，而且在支持渐进图像传输、感兴趣区图像编码和抗误码性能上也优于传统的JPEG标准和其它编码方法。本文对JPEG2000系统的结构、特性以及其编码算法进行了分析，并给出JPEG2000与原JPEG标准的性能比较。     

JPEG2000新规格制定完成

彩色表态图像的新一代编码方式“JPEG2000”的编码算法已经确定。在2000年3月的东京会议上,规定基本编码系统的最终协议草案已获发行,最终标准的推出预计在2000年12月。JPEG2000作为JPEG升级版,高压缩（低比特速率）是其目标,与JPEG相比,可同的情况下,JPEG2000信噪比将比JPEG提高30％左右,同时JPEG2000还拥有5种2值图像采用JBIG,低压缩率采用则将上术方式统一起来,成为对应各种图像的通用编码方式。JPEG2000编码算法采用离散式变DWT）和bitplain算术编码（Mqcoder）等构成,而JPEG则为DCT和Qmcoder。另外此次…     

JPEG2000标准研究及其与JPEG标准比较

随着多媒体技术和网络技术的飞速发展,JPEG标准已经无法满足人类的要求,于是产生了新一代静态图像压缩技术—JPEG2000。JPEG2000编码系统由预处理、离散小波变换(DWT)、量化和熵编码组成,其采用了DWT和优化截取嵌入块编码(EBCOT)算法,具有JPEG标准无法比拟的优势。介绍了JPEG2000编码系统的组成、优点以及与JPEG的对比。实验证明,相同压缩率下,JPEG2000压缩比JPEG获得了更好的图像质量。     

JPEG2000的重要性编码

讨论一种利用图像重要性测度实现静态图像压缩标准JPEG2000编码方法。JPEG2000编码器的技术核心是离散小波变换和：EBCOT，而EBCOT是由两个编码引擎T1，T2组成的，其中T2编码主要是完成码流的组织，其方法是灵活多变的，用户可以根据特殊要求组织码流，只要码流的格式符合JPEG2000的格式即可。本文根据编码图像小波域的系数和时域的像素值计算该系数的重要性，并利用重要性组织完全符合JPEG2000格式的码流。可以利用标准JPEG2000解码器对本算法形成的码流进行解码。     

新一代静止图像压缩标准JPEG2000

随着多媒体应用领域的扩展,传统的图像压缩技术已无法满足人们对多媒体图像的要求,各种图像压缩格式应运而生,如JPEG、MPEG-4VTC、PNG等。其中新一代ISO/ITU-T静止图像压缩标准JPEG2000成为热点。文章重点介绍JPEG2000图像编码系统的基本思想及其特性。     

Visibility of quantization errors in reversible JPEG2000

Image compression systems that exploit the properties of the human visual system have been studied extensively over the past few decades. For the JPEG2000 image compression standard, all previous methods that aim to optimize perceptual quality have considered the irreversible pipeline of the standard. In this work, we propose an approach for the reversible pipeline of the JPEG2000 standard. We introduce a new methodology to measure visibility of quantization errors when reversible color and wavelet transforms are employed. Incorporation of the visibility thresholds using this methodology into a JPEG2000 encoder enables creation of scalable codestreams that can provide both near-threshold and numerically lossless representations, which is desirable in applications where restoration of original image samples is required. Most importantly, this is the first work that quantifies the bitrate penalty incurred by the reversible transforms in near-threshold image compression compared to the irreversible transforms.     

JPEG2000 - choices and tradeoffs for encoders

A new and improved image coding standard, called JPEG2000, has been developed. JPEG2000 is the state-of-the-art image coding standard that results from the joint efforts of the International Standards Organization (ISO) and the International Telecommunications Union. In this article, we describe the most important parameters of this new standard and present several "tips and tricks" to help resolve the design tradeoffs that JPEG2000 application developers are likely to encounter in practice. The new standard outperforms the older JPEG standard by approximately 2 dB of peak signal-to-noise ratio (PSNR) for several images across all compression ratios. The JPEG2000's superiority from the previous standard largely depends on the standard's security aspects, interactive protocols and application program interfaces for network access, wireless transmission, wavelet transform, and embedded block coding with optimal truncation (EBCOT).     

简析JPEG2000的核心算法——EBCOT

JPEG2000是国际标准化组织(ISO)指定的新一代静止图像压缩标准。它作为JPEG的升级版，向下兼容，具有比JPEG更高的压缩率，同时具有一些新的特征。这里主要介绍了JPEG2000中的核心算法EBCOT(embedded block coding with optimized truncation)—基于优化截断的嵌入式块编码算法。以此阐述了JPEG2000压缩标准新的特征以及与现有压缩标准相比显示出来的优越性能。     

结构信息最优的静止图像压缩算法研究

JPEG2000是基于小波变换的新一代静止图像压缩标准,与以往的压缩标准相比,其具有很多优点。但是JPEG2000以MSE作为图像失真评价标准,而MSE不能很好的符合人眼主观评分,进而很大地影响了JPEG2000的压缩性能。该文在JPEG2000标准框架下,提出了以结构相似度作为失真评价标准的静止图像压缩算法(SJPEG2000)。该算法以系数对图像结构信息贡献量的大小作为准则来截取码流,使压缩后的图像尽量保存原图像的结构信息。实验结果表明,该算法压缩得到的图像很好地保留了图像结构信息,压缩图像的主观质量得到提高,结构相似度值较原JPEG2000也有一定提高。     

JPEG 2000: Retrospective and New Developments

JPEG 2000 is a new image coding system that delivers superior compression performance and provides many advanced features in scalability, flexibility, and system functionalities that outperform all previous standards. It brings exciting possibilities to many imaging applications such as the Internet, wireless, security, and digital cinema. This paper gives an overview of this triumph in innovations and teamwork. It gives brief introductions to the four new parts that are under development by the JPEG committee. It attempts to summarize the lessons learned from the JPEG 2000 development experience and draw some conclusions on the success factors of this important standard.     

ADV-JP2000及其在数码相机中的应用

ADV -JP2000是AnalogDevice公司为新的静止图像压缩标准JPEG2000而生产的专用压缩芯片 ,该芯片可灵活应用于各种静止图像压缩场合。文中主要介绍了ADV -JP2000的工作过程 ,给出了用ADV -JP2000为处理核心的数码相机系统的设计方案     

Automated optimization of JPEG 2000 encoder options based on model observer performance for detecting variable signals in X-ray coronary angiograms

Image compression is indispensable in medical applications where inherently large volumes of digitized images are presented. JPEG 2000 has recently been proposed as a new image compression standard. The present recommendations on the choice of JPEG 2000 encoder options were based on nontask-based metrics of image quality applied to nonmedical images. We used the performance of a model observer [non-prewhitening matched filter with an eye filter (NPWE)] in a visual detection task of varying signals [signal known exactly but variable (SKEV)] in X-ray coronary angiograms to optimize JPEG 2000 encoder options through a genetic algorithm procedure. We also obtained the performance of other model observers (Hotelling, Laguerre-Gauss Hotelling, channelized-Hotelling) and human observers to evaluate the validity of the NPWE optimized JPEG 2000 encoder settings. Compared to the default JPEG 2000 encoder settings, the NPWE-optimized encoder settings improved the detection performance of humans and the other three model observers for an SKEV task. In addition, the performance also was improved for a more clinically realistic task where the signal varied from image to image but was not known a priori to observers [signal known statistically (SKS)]. The highest performance improvement for humans was at a high compression ratio (e.g., 30:1) which resulted in approximately a 75% improvement for both the SKEV and SKS tasks.     

JPEG2000标准的核心算法及最新进展

阐述了JPEG2000的发展历程及组成结构、JPEG2000 Part 1的图像压缩过程及相应技术，并对JPEG2000标准最新的四个部分做了简要介绍。