点类几何数据无损压缩算法的研究

在对矢量图数据的存储特性进行深入研究的基础上,提出了综合运用通用无损数据压缩算法和几何压缩算法的两步压缩策略。根据矢量图数据中各几何图形要素的不同存储特点,特别是根据点类文件的特点,研究实现了有效的点类几何数据无损压缩算法。     

一种通用多媒体数据压缩技术的实现研究

本文叙述了一种基于ＬＺＷ的通用数据压缩算法及实现，它将多媒体的图象、语音、文本等数据的压缩处理集为一体，用同一种算法压缩各种不同类型的多媒体数据。同时，通过实验讨论了有关无损压缩的理论极限问题。     

遥测噪声数据无损压缩算法研究

介绍了数据压缩的现状,分析了遥测噪声数据的特点和无损压缩算法的原理.根据噪声数据特点,通过各个算法比较和相关验证性实验,提出了Lz+ARC数据无损压缩算法,重点介绍了该无损压缩算法的原理和实现过程,并将该算法原理针对大量噪声数据进行了仿真压缩,结果表明压缩去除率可达到60%～90%.     

遥测噪声数据无损压缩关键技术实现

提出了采用DSP+FPGA架构搭建硬件平台,通过ARC算法实现对多路噪声数据无损压缩的设计方法。对设计中关键技术(如模/数转换、数据缓冲设计和DSP程序设计)作了详细的说明。采用测试平台对设计的噪声数据压缩装置的性能进行了验证,结果表明该装置对噪声数据压缩效果明显,噪声信号还原效果理想,实现了对噪声数据的无损压缩,能够很好地满足遥测系统的需要。     

基于ARC算法的数据压缩技术和实现

针对无损压缩技术在航天遥测系统中的应用情况,提出了基于现场可编程门阵列(FPGA)和数字信号处理器(DSP)硬件结构的遥测噪声数据实时无损压缩系统的方案。结合Shannon信息论中信息熵的概念,研究了数据压缩的本质和算法评估标准。通过PC仿真试验对多种算法的压缩效果进行了比较,最终选择算术编码(ARC)作为无损压缩的算法。测试结果表明,该方案能够实时采集并压缩遥测噪声数据,有效地提高压缩去除率和压缩速度,优化压缩性能。     

地震数据的无损压缩存储

为解决地震数据的无损压缩存储问题,研究了多种地震数据标准以及整型和浮点型数据的无损压缩算法.在此基础上,提出了地震数据的无损压缩存储方法.该方法通过分析多种地震标准的内部结构特点,有针对性地对整型和浮点型数据分别进行无损压缩.在保证了地震数据文件中各参数、标识等信息不被破坏的条件下,最大限度地减小了地震数据文件的大小.试验证明,本方法不仅对整型数据而且对于浮点型数据都可以做到无损的数据压缩与还原.     

利用优化哈夫曼编码进行数据压缩的探索

数据压缩是当今计算机科学领域中十分活跃的论题. 哈夫曼编码作为一种最常用的不等长无损压缩编码方法,在数据压缩程序中具有非常重要的应用.文章通过对传统静态哈夫曼编码的讨论以及与动态哈夫曼编码的对比,研究一种改进的数据压缩算法,并用程序实现之.     

利用优化哈夫曼编码进行数据压缩的探索

数据压缩是当今计算机科学领域中十分活跃的论题。哈夫曼编码作为一种最常用的不等长无损压缩编码方法，在数据压缩程序中具有非常重要的应用。文章通过对传统静态哈夫曼编码的讨论以及与动态哈夫曼编码的对比，研究一种改进的数据压缩算法，并用程序实现之。     

基于FPC和区间编码的工业浮点数据的压缩传输

为解决大量工业浮点数据在GPRS网络上传输时实时性降低的问题,提出了基于科学计算双浮点数压缩算法（FPC）与区间编码相结合的无损压缩方法IFPC实现工业浮点数据的压缩传输及解压缩。先对FPC算法与通用无损压缩算法应用在浮点数部分时的压缩效果作实验对比,实验结果表明FPC算法相比于通用的无损压缩算法在浮点数压缩上具有较好的压缩率以及较短的压缩与解压缩时间。将FPC算法与区间编码结合后的IFPC算法对整个数据域压缩与解压缩的实验结果表明,所提出的方法相比通用无损压缩算法,压缩率最低可提高7.6%,压缩时间最低可减少49.1%,综合传输时间减少了21.3%,提高了传输实时性。     

一种JPEG无损压缩算法的仿真与实现

研究图像压缩算法优化算法的效果,针对目前通用无损压缩算法都难以对JPEG文件进行压缩,提出了一种洗牌算法和无损压缩算法相结合的无损压缩方法。在将JPEG图像文件进行压缩前对文件进行有效规整,产生冗余,然后再结合通用无损压缩算法进行无损压缩进一步去除文件内部信息冗余。进行仿真实验验证,算法能够进一步将JPEG图像文件无损压缩1%-3%。结果表明,上述算法能进一步无损去除文件内部冗余,减小文件体积,算法简单,时间复杂度低,易于实现,是一种有效的快速图像压缩算法。算法已经获得专利保护。     

An effective method for still image compression/decompression for transmission on PSTN lines based on modifications of Huffman coding

This paper presents an effective compression method suitable for transmission the still images on public switching telephone networks (PSTN). Since compression algorithm reduce the number of pixels or the gray levels of a source picture, therefore this will lead to the reduction of the amount of memory needed to store the source information or the time necessary for transmitting by a channel with a limited bandwidth. First, we introduced some current standards and finally the lossy DCT-based JPEG compression method is chosen. According to our studies, this method is one of the suitable methods. However, it is not directly applicable for image transmission on usual telephone lines (PSTN). Therefore, it must be modified considerably to be suitable for our purposes. From Shannon’s Information Theory, we know that for a given information source like an image there is a coding technique which permits a source to be coded with an average code length as close as to the entropy of the source as desired. So, we have modified the Huffman coding technique and obtained a new optimized version of this coding, which has a high speed and is easily implemented. Then, we have applied the DCT¹ and the FDCT² for compression of the data. We have analyzed and written the programs in C++ for image compression/decompression, which give a very high compression ratio (50:1 or more) with an excellent SNR.³In this paper, we present the necessary modifications on Huffman coding algorithms and the results of simulations on typical images.     

Box Car过程数据压缩算法性能分析

Box Car过程数据压缩算法在现场总线控制系统中得到广泛采用。其压缩效果受记录限和压缩区间的影响。本文基于对典型仿真数据的大量计算,分析了Box Car过程数据压缩算法记录限和压缩区间对趋势平稳的过程数据的压缩比、计算时间和压缩系数的影响。本文还分析了过程数据趋势特征和波动特性对Box Car算法压缩比和逼近系数的影响。本文的计算结果对于在实际应用中根据过程数据不同的趋势和噪声特征调整Box Car压缩算法参数以获得理想的压缩效果具有指导意义。     

基于HBase的列存储压缩策略的选择优化

大数据时代背景下,列存储数据库使用场景愈加增多,推动了列存储相关领域的研究进展。为解决现有列存储数据库压缩策略在压缩过程中遇到的数据离散程度大,分类粒度小,配套分类算法缺陷导致的学习成本高,压缩效率难以保证的问题,本文提出了一种基于排序的列区混合压缩策略,首先根据HBase特点设计了一种对各列数据进行排序的方法加强数据紧密度,然后根据数据特点分别使用混级区压缩策略和混级列压缩策略进行压缩策略推荐,在TPC-DS标准数据集上与前人策略进行比较,实验结果显示本文方法在压缩率、压缩/解压时间方面均有优异的表现,从而证明了本文方法的有效性。     

The compression of a sequence of satellite images based on change detection

A 'loss-effective' compression method which based on the change detection of raw image data is proposed for dealing with a sequence of satellite images. The average compression ratio we gained, compared with some typical satellite image formats, is about 2:1 to 3 :1. This sounds not so impressive when compared with the most current compression techniques which used in multimedia processing. However, some information will be lost in those methods, while our approach is information-loss effective, which is crucial for further satellite image analysis. Moreover, the framework can be combined with different compression algorithms to obtain different trade-offs between the compression ratio and the computation time. Experimental results based on real satellite images are included. Finally, other issues including the further optimization of the methods and some other possible applications of the method are discussed.     

面向WSN节点的数据压缩算法的应用研究

本文根据无线传感器网络(WSN)节点对数据压缩的需要和节点存储空间和能量受限的特点,分析了面向WSN节点的数据压缩的特点和研究意义。针对资源受限节点对压缩精度和算法运算量的不同需求,提出了在典型节点处理器上基于傅立叶级数实现数据压缩的简化应用方法。仿真实验表明了在WSN节点平台上应用该压缩算法的有效性。     

多媒体数据压缩技术的研究

随着计算机网络和计算机通信技术的发展,数据压缩技术越来越成为多媒体技术中的研究热点,本文针对数据压缩技术进行了深入研究,对数据压缩技术进行了分类,并分析和比较了这一研究领域中典型压缩算法的原理与性能。     

Image Compression and Video Segmentation Using Hierarchical Self-Organization

Both image compression based on color quantization and image segmentation are two typical tasks in the field of image processing. Several techniques based on splitting algorithms or cluster analyses have been proposed in the literature. Self-organizing maps have been also applied to these problems, although with some limitations due to the fixed network architecture and the lack of representation in hierarchical relations among data. In this paper, both problems are addressed using growing hierarchical self-organizing models. An advantage of these models is due to the hierarchical architecture, which is more flexible in the adaptation process to input data, reflecting inherent hierarchical relations among data. Comparative results are provided for image compression and image segmentation. Experimental results show that the proposed approach is promising for image processing, and the powerful of the hierarchical information provided by the proposed model.     

无线传感器网络中一种分布式数据压缩算法

无线传感器网络有限的能量与通信带宽难以适应网络中大量数据的传输,需要在网络内部对传感数据进行压缩处理。基于任意支撑长度的小波函数,提出了一种分布式数据压缩算法。首先研究边界效应对传感数据重构带来的影响,然后基于虚拟网格环模型给出了一种分布式小波数据压缩算法。理论分析与实验结果表明,该算法能有效地去除传感数据中存在的空间相关性。而且,随着簇头与簇内节点距离的增加,该算法比非分布式方式更节省网络耗能。     

CCIGS: A data compression system for Chinese fonts and binary images using classification techniques

To achieve a high compression ratio when storing a large amount of Chinese characters is a problem in applications using Chinese characters. In this paper, we present a data compression software system which can reduce the storage requirement of Chinese characters and binary images. This system is composed of a Chinese font compressing subsystem and a binary image compressing subsystem. In the Chinese font compressing subsystem we have improved the traditional methods of feature extraction and classification techniques so as to achieve a high compression ratio in the compression of Chinese characters. Based on the technique of this subsystem, we have combined the block segmentation technique to compress a binary image. In addition to achieving a good data compression ratio the encoding-decoding process is computationally very efficient in our system. We also show that with our system the quality and accuracy of the reconstructed pattern and image are very close to those of the original pattern and image.     

基于脊波变换的体数据压缩编码方法

体数据的数据量大、数据间的相关性强、拥有大量的线或面结构,因此需要研究有效的压缩编码方法。脊波变换作为一种新的时频分析工具,在处理线或面的奇异性时有它适用的一面。在介绍脊波变换理论的基础上,将脊波变换的思想应用到体数据的压缩编码中。文中两种压缩策略的主要思想分别为：策略1先将体数据划分成切片组,再对每一张切片做二维脊波变换,然后进行量化和熵编码;策略2直接对体数据做类似于三维脊波变换的变换,然后进行量化和熵编码。比较而言,策略1实现简单,策略2能获得更高的压缩比。两种策略都具有较强的鲁棒性,且能实现嵌入式编码。该方法已应用到实际工业CT体数据的压缩编码中,还可用于其它类型体数据的压缩编码中。