Description: Huffman编码实现数字图象压缩，解压．对数字图象的压缩的步骤之一编码和解压步骤之一解码有很大的帮助．-Huffman coding of digital image compression, decompression. On digital image compression encoding one of the steps towards one of the steps to extract and decode a great help. Platform: |
Size: 10240 |
Author:梦铃 |
Hits:
Description: 摘 要
文章以空间监控系统为背景,深入研究了JPEG图像压缩标准的实现方法,并基于FPGA对其进行了实现和优化。文中给出了详细的实现方法和优化过程,测试表明达到了很好的效果。
简单介绍了有损静态图像压缩当前有两种比较流行的标准JPEG和JPEG2000。说明了用JPEG方法压缩的原因。
介绍JPEG基本原理：JPEG对灰度图像的压缩处理过程主要包括:图像分割,离散余弦变换(DCT),量化(Quantization),“Z”形排序(Zigzag Scan),差分脉冲编码调制(Differential Pulse Code Modulation,DPCM)对直流系数(DC),行程长度编码(Run-Length Encoding,RLE)对交流系数(AC),霍夫曼(Huffman)编码等。
JPEG标准的特点是离散余弦变换。
比较详细介绍压缩系统的构成和实现。实现提及步骤， JPEG压缩模块设计和编码模块实现细节。
-Abstract
Article in the space monitoring system for the background, in-depth study of the JPEG image compression standard implementation methods and carried out based on FPGA implementation and optimization. In this paper, a detailed method of implementation and optimization of the process, testing showed that to achieve good results.
Easy introduction of harmful static image compression has two kinds of comparisons that the current popular standard JPEG and JPEG2000. Illustrated by the reasons for JPEG compression method.
JPEG introduce the basic principles: JPEG compression of gray-scale image processing include: image segmentation, discrete cosine transform (DCT), quantization (Quantization), "Z"-shaped sort (Zigzag Scan), differential pulse code modulation (Differential Pulse Code Modulation, DPCM) on the DC coefficient (DC), Run Length Encoding (Run-Length Encoding, RLE) of the exchange coefficient (AC), Hoffman (Huffman) coding.
JPEG standard is characterized by discrete Platform: |
Size: 523264 |
Author:压子 |
Hits:
Description: 利用霍夫曼编码算法对数字图像进行压缩及解压缩处理，解压出来的图像与源图像几乎完全一致，峰值信噪比为无穷大-The use of Huffman coding algorithm for digital image compression and decompression processing, extracting images from the source image is almost exactly the same infinite PSNR Platform: |
Size: 168960 |
Author:tianjieyu |
Hits:
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: 1024 |
Author:Ho Joon Lee |
Hits:
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 |
Hits:
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: 128000 |
Author:Ho Joon Lee |
Hits:
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: 189440 |
Author:Ho Joon Lee |
Hits:
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 |
Hits:
Description: 对不同格式数字图像进行哈夫曼编码压缩，通过matlab软件仿真，最后得到了压缩图像，实现了本课题的基本要求。通过仿真得知哈夫曼编码为无损压缩。-Huffman coding digital image in a different format, by Matlab software emulation, finally got the compressed image, to achieve the basic requirements of this topic. Through simulation that Huffman coding for lossless compression. Platform: |
Size: 4096 |
Author:李石峰 |
Hits:
Description: hufman
coding. Input QUALITY determines the amount of information that
is lost and compression achieved. Y is an encoding structure
containing fields:
Y.size Size of X
Y.numblocks Number of 8-by-8 encoded blocks
Y.quality Quality factor (as percent)
Y.huffman Huffman encoding structure, as returned by
MAT2HUFF
See also JPEG2IM.
Copyright 2002-2006 R. C. Gonzalez, R. E. Woods, & S. L. Eddins
Digital Image Processing Using MATLAB, Prentice-Hall, 2004
$Revision: 1.5 $ $Date: 2006/07/15 20:44:34 $
Revised: 3/20/06 by R.Woods to correct an eob coding problem, to
check the quality input for <-hufman
coding. Input QUALITY determines the amount of information that
is lost and compression achieved. Y is an encoding structure
containing fields:
Y.size Size of X
Y.numblocks Number of 8-by-8 encoded blocks
Y.quality Quality factor (as percent)
Y.huffman Huffman encoding structure, as returned by
MAT2HUFF
See also JPEG2IM.
Copyright 2002-2006 R. C. Gonzalez, R. E. Woods, & S. L. Eddins
Digital Image Processing Using MATLAB, Prentice-Hall, 2004
$Revision: 1.5 $ $Date: 2006/07/15 20:44:34 $
Revised: 3/20/06 by R.Woods to correct an eob coding problem, to
check the quality input for < Platform: |
Size: 12288 |
Author:karimak |
Hits:
Search - image compression by huffman coding matlab