A valid method , but because it uses subbands " redundancy , the complexity is so much that the compressing process consumes much time . so the efficiency of wavelet coding depends on bit allocation , that is , definite bits must be allocated to a serial of quantization validly . by using kinds of quantization tables , each quantization can work at kinds of rates 小波变换的图像压缩算法虽然是一种有效的算法,但因为它利用了不同子带间和各个子带内部的相关性,所以复杂度比较高,有时不能实现实时的要求,因而小波变换编码方案的有效性很大程度上依靠比特分配,即给定的比特数必须被有效地分配在不同子带中。
In all kinds of complicated network , oriented linking and unlinking , communication frequency resource is strained , and bandwith to transmitting audio frequency signal is too restricted , complicated and fluky , while audio frequency data exponential have been increased in the last several years . under the circumstances , based on the research of predecessor , this paper studies wavelet analysis ' s maths gist and practices significance on signal process , and puts forward a optimized wavelet package condensation arithmetic to process audio frequency data , which gives attention to coding efficiency , multirate and compression delay . simulation experiment on the arithmetic has been done by matlab 针对无连接和面向连接的各种复杂网络环境下,通信频带资源紧张,音频传输带宽有限且复杂多变,而各种音频数据又日益增多的局面,本文研究小波分析在信号处理方面的数学依据和在数据压缩方面的实际意义,在前人不断工作的基础上,提出了一种优化小波包变换编码方案用于音频数据的压缩算法,兼考虑了编码效率、多码率和压缩时延多个方面,并在matlab环境下做了仿真实验,对各种音频信号及多种小波函数做了仿真结果比较,实验结果证明该算法可以在一定计算复杂度下可以很好地改进压缩效果,达到多码率下实现实时编解码的过程,在高速dsp芯片等硬件设备支持下,可以有效应用于实际复杂多变信源编码。
First the survey of video encoding development has been conducted , then the video compression technology has been introduced and the application of fpga and dsp processor in video compression field is appended , finally the hardware implementation of video compressor based on h . 263 standard is introduced . according to the characteristic of fpga , we bring forward the motion estimate and dct / idct arith metic which can be easily implemented in hardware 首先介绍了视频压缩编码发展的概况;然后介绍基于变换编码的视频压缩方法,并介绍fpga和dsp处理器在视频压缩编码器中的应用;最后介绍了基于h . 263标准的视频压缩编码器硬件实现,并根据fpga的特点,提出适合其实现的运动估值算法和dct和idct算法。
The basic aim of image compression is minimizing the distortion with the needed bit - rate . the image compression based on wavelet transform is a valid method , but because it uses subbands " redundancy , the complexity is so much that the compressing process consumes much time . so the efficiency of wavelet coding depends on bit allocation , that is , definite bits must be allocated to a serial of quantizations validly 小波变换的图像压缩算法虽然是一种有效的算法,但因为它利用了不同子带间和各个子带内部的相关性,所以复杂度比较高,有时不能实现实时的要求,因而小波变换编码方案的有效性很大程度上依靠比特分配,即给定的比特数必须被有效地分配在不同子带中。
Then . this paper analyzes h . 263 - protocol for video coding which is the core part of the system . the h . 263 protocol integrates the prediction coding dct transform coding and entropy coding to realize the compression for video data . in addition , it describes the codec architecture and data format . this paper ( 1 ) presents a effective algorithm of motion estimation for inter - frame prediction coding ; ( 2 ) analyzes the way implementing 2 dimension dct transform by algorithm of 1 dimension fast dct transform ; ( 3 ) optimizes the above procedures with the mmx and sse of intel . then comes up with an effective dct algorithm 接着,着重分析了系统的核心部分: h . 263视频编码协议。该协议将预测编码、 dct变换编码和熵编码相结合实现对视频数据的压缩,并规定了编码器的总体结构和数据格式。本文( 1 )提出了一种有效的运动估计算法进行帧间预测编码; ( 2 )分析了通过一维dct快速算法完成二维dct变换编码的方法; ( 3 )应用intel的mmx和sse对上述过程进行了优化,并结合mmx和sse技术提出了一种有效的dct计算方法。
During the latest 20 years , great progress has been made in the theory , method and technology of image - compression coding on the basis of such traditional coding methods as coding forecast and exchanger coding etc ; wavelet transformation has been widely used in signal - disposal field , because it has a characteristic of energy focus , it puts forwards a concept of multi - resolution ration analysis and the realization o f algorithm about wavelet decompose and fast rebuild . among the applications of wavelet analysis , it is rather mature to apply it to image - data compressing 近20年来,在预测编码、变换编码和其它传统编码方法的基础上,图像压缩编码的理论、方法和技术取得了较大进展;其中小波编码算法因其能量集中特性、多分辨分析概念的提出和小波分解与重构快速算法的实现,使得小波变换在信号处理领域得到了广泛的应用,小波分析应用于图像数据压缩是小波分析应用的一个比较成熟的方面。
The design of hardware including : a digital video codec / decodec chip ( adv611 ) produced by ad inc . based on wavelet transform ; a usb controller ( pidusb12 ) collecting the compressed digital video signal ; a spread spectrum platform ( at - 340dsh ) sending / receiving the spread spectrum signal ; and a dsp controlling the all system 硬件部分的设计:小波变换编码部分选用ad公司的adv611芯片;视频的采集通过usb口;信道部分选择了基于扩频技术的无线扩频平台at ? 340dsh ;整个系统由ti公司的tms320vc5402作为主控机来完成。
Discrete cosine transform ( dct ) is one of common transform encoding technique in common use of image compression . because such advantages as relatively matured theory , arithmetic and hardware ; ease to move relativity ; fit human vision system ; less calculation ( not include plural calculation ) : ease to realize and so on , dct compression is widely used 离散余弦变换( dct )是图像压缩中经常用到的正交变换编码技术,由于理论、算法和硬件相对成熟,去相关性好,适应人眼的视觉特性,计算量不大(没有复数计算) ,易于实现等优点, dct压缩编码的应用非常广泛。
Image code is a developing field on image compress and a lot of methods on that has now generated , such as statistic code , predict code , transform code , subband code , model code , wavelet transform code , vector quantization code , neural networks code , fractal code etc . in this thesis , we mainly describe our work on vector quantization code and wavelet transform code on image compress 常见的图像压缩编码方法有:统计编码,预测编码,变换编码,子带编码,模型基编码,小波变换编码,矢量量化编码,神经网络编码,分形编码等。本文以矢量量化压缩编码和小波变换压缩编码这两种图像压缩编码方法为主要研究对象。
By first reviewing the basic video coding theory and then analyzing kinds of sub - module in video coding system . adaptive overlapped block motion compensation ( aobmc ) is combined with pds technology for temporal prediction . the system composed of hybrid transform coding and motion compensation prediction coding is constructed 第五章讨论了本文运动估计和运动补偿方法在视频编码中的应用,首先阐述了视频编码理论和编码系统各个子模块的基本原理,然后在预测性菱形搜索和自适应重叠块运动补偿基础上运用变换编码加运动补偿的预测编码方法实现一个混合视频编码的方案。