Description: 本文结合DCT变换的特性，利用分形的Peano一hilbert扫描曲线，对基于DCT变换的图像编码方法进行了研究，并提出了改进方法。主要工作分为两个部分: 一是在分块DCT基础上的改进。对分块后生成的各图像块矩阵，不直接作二维DCT变换，而是先进行扫描，使之重排成一维向量，再进行一维DCT变换，这样可以减少运算量。 其次是对层次余弦变换编码部分的改进。使用层次DCT变换与零树编码相结合的方法，并在扫描编码过程中，按Peano一hilbert扫描顺序进行编码。这样不仅可以减少“块效应”，而且可以加快编码速度。-this paper the characteristics of DCT, using fractal Peano a Hilbert scanning curve, the DCT-based image coding method for the study and improvement of methods. The work is divided into two main parts : First, the DCT block on the basis of improvements. Right after block production of the image block matrix, not for direct two-dimensional DCT, but first scan, so they line up in a heavy-dimensional vector and then a peacekeeping DCT, thus reducing the amount of computation. Secondly, the level of cosine transform coding some of the improvements. The use level of DCT and zero tree coding combination of methods, coding and scanning process, according to a Hilbert Peano code scanning sequence. This will not only reduce the "blocking effect" but we can speed up the coding speed. Platform: |
Size: 5011456 |
Author:lzy |
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Description: 这是使用小波变换,jpeg以及DCT变换对图像进行的压缩
-This is the use of wavelet transform, and the DCT jpeg images of the compression Platform: |
Size: 563200 |
Author:yangfeng |
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Description: 介绍了JPEG图像压缩算法,并在MATLAB 数学分析工具环境下从实验角度出发,
较为直观地探讨了DCT 在JPEG图像压缩中的应用。仿真实验表明,用MATLAB 来实现离散余弦
变换的图像压缩,具有方法简单、速度快、误差小的优点,大大提高了图像压缩的效率和精度。
李秀敏1 , 万里青1 , 周拥军2
(1. 河南科技大学电子信息工程学院,河南洛阳 471003 2. 中航一集团洛阳电光设备研究所,河南洛阳 471009)-introduced the JPEG image compression algorithm, MATLAB and mathematical analysis tool environment from experimental perspective, more directly on the DCT in JPEG image compression applications. Simulation results show that the use MATLAB to achieve discrete cosine transform image compression method is simple, fast, the advantages of a small error, which has greatly enhanced the efficiency of image compression and accuracy. LI Xiu-1, Green 1 Wanli, Zhou Yongjun 2 (1. Henan University of Science and Technology of Electronics and Information Engineering College, Luoyang, Henan 471003 2. A350 Luoyang Electro-Optic Equipment Institute, Luoyang, Henan 471009) Platform: |
Size: 108544 |
Author:adnsid |
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Description: 余弦变换压缩，用于图像压缩，压缩比高，且压缩后图像质量仍然很好。适用于灰度图象。-Cosine Transform compression for image compression, compression ratio, and compressed image quality is still good. Apply to the gray-scale image. Platform: |
Size: 34816 |
Author:张弛 |
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Description: 本程序的目的是通过变化DCT系数以及寻找可以应用的DCT系数的最小值来进行可扩展的MPEG压缩，并且能都达到一个可以接收的效果。-the purpose of this procedure is adopted, as well as changes in DCT coefficients can be used to find the minimum value of the DCT coefficients to Progressive firms will be able to expand the MPEG compression, and can achieve an acceptable result. Platform: |
Size: 84992 |
Author:麦田 |
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Description: 实现基本JPEG的压缩和编码分三个步骤:
1. 首先通过DCT变换去除数据冗余；
2. 使用量化表对DCT系数进行量化；
3. 对量化后的系数进行Huffman编码。-Realize the basic JPEG compression and encoding is divided into three steps: 1. First of all, through the DCT transform to remove data redundancy 2. The use of quantization table of quantization DCT coefficients 3. Quantization coefficients after Huffman coding. Platform: |
Size: 2048 |
Author:后果 |
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Description: 使用DCT算法实现8X8的BMP图像压缩的一个源代码，希望对大家有用~-8x8 algorithm using DCT image compression of BMP, a source code, in the hope that useful to everyone ~ Platform: |
Size: 3072 |
Author:viconia |
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Description: 利用DCT变化对tif图像进行压缩利用DCT变换进行图像压缩的MATLAB程序-Changes in the use of DCT compression of tif images using DCT transform image compression MATLAB program Platform: |
Size: 802816 |
Author:ruiomar |
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Description: 三维DCT变换是在空间信息上增加了一维的时间维度，对视频系列直接进行压缩-Three-dimensional DCT transform information in the space are added to one-dimensional time dimensions of the video series for direct compression Platform: |
Size: 14336 |
Author:farmer |
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Description: 已知两个不同图像块亮度数据如下：
（1）分析DCT原理，采用DCT方法，编程并计算相应的DCT系数，分析系数分布特点。
（2）依据视觉特性分析量化表步长的分布特点，完成DCT系数量化。
（3）采用Z形扫描，实现输出数据的统计编码，形成Video stream。
（4）采用IDCT重建图像亮度数据，计算SAD大小，分析产生误差的原因及采用DCT进行数据压缩的原理。（ ）
（5）分别利用左上角1、3、6个系数重建图像，计算相应的SAD，并由此分析直流和低频系数的重要性。
-Known brightness of two different image data block is as follows: (1) Principles of analysis of DCT, the DCT method, program and calculate the corresponding DCT coefficient, analysis of distribution coefficients. (2) quantitative analysis based on visual characteristics of the distribution of long-form features step-by-step to complete the DCT coefficient quantization. (3) the use of Z-scan output data to achieve statistical encoding, the formation of Video stream. (4) the use of the reconstructed image brightness IDCT data to calculate the SAD size, analysis of the causes of errors and the use of DCT for the principle of data compression. () (5), respectively, a factor of 1,3,6 using the upper left corner of the reconstruction of images, calculating the corresponding SAD, and the resulting analysis of DC and the importance of low-frequency coefficients. Platform: |
Size: 1024 |
Author:张元 |
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Description: This a JPEG encoding & decoding program of still image. It does not use level shifting. Discrete Cosine transform (DCT) is performed both by classical & Chen s Flowgraph methods. Predefined JPEG quantization array & zigzag order are used here. RUN - LEVEL coding is used instead of Huffman coding. Compression ratio is compared for each DCT method. Effect of coarse and fine quantization is also examined. The execution time of 2 DCT methods is also checked. In addition, most energatic DCT coefficients are also applied to examine the effect in MatLab 7.4.0 R2007a. Input is 9 gray scale pictures & output is 9*9=81 pictures to compare. Blocking effect is obvious.
-This is a JPEG encoding & decoding program of still image. It does not use level shifting. Discrete Cosine transform (DCT) is performed both by classical & Chen s Flowgraph methods. Predefined JPEG quantization array & zigzag order are used here. RUN - LEVEL coding is used instead of Huffman coding. Compression ratio is compared for each DCT method. Effect of coarse and fine quantization is also examined. The execution time of 2 DCT methods is also checked. In addition, most energatic DCT coefficients are also applied to examine the effect in MatLab 7.4.0 R2007a. Input is 9 gray scale pictures & output is 9*9=81 pictures to compare. Blocking effect is obvious.
Platform: |
Size: 3072 |
Author:Ho Joon Lee |
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Description: This a JPEG encoding & decoding program of still image. It does not use level shifting. Discrete Cosine transform (DCT) is performed both by classical & Chen s Flowgraph methods. Predefined JPEG quantization array & zigzag order are used here. RUN - LEVEL coding is used instead of Huffman coding. Compression ratio is compared for each DCT method. Effect of coarse and fine quantization is also examined. The execution time of 2 DCT methods is also checked. In addition, most energatic DCT coefficients are also applied to examine the effect in MatLab 7.4.0 R2007a. Input is 9 gray scale pictures & output is 9*9=81 pictures to compare. Blocking effect is obvious.
-This is a JPEG encoding & decoding program of still image. It does not use level shifting. Discrete Cosine transform (DCT) is performed both by classical & Chen s Flowgraph methods. Predefined JPEG quantization array & zigzag order are used here. RUN - LEVEL coding is used instead of Huffman coding. Compression ratio is compared for each DCT method. Effect of coarse and fine quantization is also examined. The execution time of 2 DCT methods is also checked. In addition, most energatic DCT coefficients are also applied to examine the effect in MatLab 7.4.0 R2007a. Input is 9 gray scale pictures & output is 9*9=81 pictures to compare. Blocking effect is obvious.
Platform: |
Size: 95232 |
Author:Ho Joon Lee |
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Description: 这个水印一般般利用DWT变换和DCT变换嵌入水印，加上了Arnold变换使图片水印的抗MP3压缩攻击有所提高。-The watermark in general as the use of DWT transform and DCT transform embedded watermark, coupled with the Arnold transform to image watermarking against MP3 compression attacks increased. Platform: |
Size: 1024 |
Author:小王 |
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Description: Implementation of JPEG compression algorithm with JFIF header being appended.This project involves writting code for following steps : Chroma subsampling,partitioning ,level shifting,DCT,quantization,zigzag scanning(involves DC differential coding & AC huffman coding) & adding jfif header following the rules specified in itu-t.81. Platform: |
Size: 966656 |
Author:dwn |
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