Description: 数字图像处理实验
根据原图像的直方图，发现背景和目标的分割值大约在130左右，并将灰度图像转为二值图像，分割效果比较理想。
图像处理实验（六）图像压缩与编码
实验目的： 学习JPEG压缩编码
实验内容：
一．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。-digital image processing experiments based on the original image histogram, found background and objectives of the divided about the value of around 130 and two gray-scale image to image, Segmentation more satisfactory results. Image processing experiments (6) Image Compression and Coding of the experiment : Learning JPEG compression coding experiment : one. Basically JPEG compression and coding in three steps : 1. First through DCT remove data redundancy; 2. Using quantitative table right DCT coefficient quantization; 3. Right quantized coefficients of Huffman coding. Platform: |
Size: 4096 |
Author:qq |
Hits:
Description: dctcom.m文件利用DCT变换完成对输入图像进行压缩；imagecbe.m完成对输入的两幅RGB图像用小波分析的方法进行图像融合 imagecom.m完成对输入的RGB图像用小波分析的方法进行自动降噪，得到高频系数阈值，降噪效果百分比和结果 wavelet1D.m完成对输入的一维信号进行多尺度离散小波分解 wavelet2D完成对输入的二维信号进行多尺度离散小波分解；zigzag.m完成对输入的8*8矩阵按照zigzag排列抽取数据.-document the use of DCT transform dctcom.m completion of the input image compression imagecbe.m completion of the two RGB input image with wavelet analysis method of image fusion imagecom.m completion of the input RGB image using wavelet analysis method automatically drop noise, the threshold of high-frequency coefficient, noise reduction effect and the results of the percentage of wavelet1D.m completion of the input signals of one-dimensional discrete wavelet multi-scale decomposition wavelet2D completion of the input signals of two-dimensional discrete wavelet multi-scale decomposition zigzag.m completed the input of 8* 8 matrix of data collected in accordance with the zigzag order. Platform: |
Size: 3072 |
Author:zhouhao |
Hits:
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 |
Hits:
Description: Matlab source code for DCT-based watermarking for grayscale images. DCT-based watermark recovering without resorting to the uncorrupted original image. Digital watermarking has been proposed as a viable solution to the need of copyright protection and authentication of multimedia data in a networked environment, since it makes possible to identify the author, owner, distributor or authorized consumer of a document.
A new watermarking technique to add a code to digital images is presented: the method operates in the frequency domain embedding a pseudo-random sequence of real numbers in a selected set of DCT coefficients. Watermark casting is performed by exploiting the masking characteristics of the Human Visual System, to ensure watermark invisibility. The embedded sequence is extracted without resorting to the original image, so that the proposed technique represents a major improvement to methods relying on the comparison between the watermarked and original images.
Platform: |
Size: 98304 |
Author:omar |
Hits:
Description: 1.对一个256*256的图像进行DCT变换得到图像D，将D得斜下角数值置为零，然后进行DCT反变换.
2.对源图像进行K-L转换
1和2比较-1.Get a grey level image which size is N*N. (For example, 256*256, however,
N = ), and partition to 8*8 sub images.
2.. Apply DCT to these sub images, and get the transformed image D with DCT
coefficients for elements.
3. From D, keep the coefficient values for only upper left triangular region and set
zeros for lower right region to approximate the image. (That is, only half of data
is used.)
4.Take Inverse DCT to get the approximated image.
2 . Get the covariance matrix of image.
3 . Calculate the corresponding eigenvectors and eigenvalues.
4 . Represent the original image with Singular Value Decomposition.
5 . Approximate the image by taking off the 4 smallest eigenvalues. (That is, only
half of information is used.)
Platform: |
Size: 1024 |
Author:zhengyan |
Hits:
Description: DCT-based Data hiding: dataHide.m Hide the logo image into the original
dataExtract.m Extract the logo image from the original findData.m Verify the robustness of the data hiding method 。and use jpeg compress
-DCT-based Data hiding: dataHide.m Hide the logo image into the original dataExtract.m Extract the logo image from the original findData.m Verify the robustness of the data hiding method. and use jpeg compress Platform: |
Size: 5120 |
Author:潘 |
Hits:
Description: 本文算法是将24 位真彩图的亮度分量分块
DCT ,然后利用DCT 量化系数的奇偶特性嵌入8
位灰度水印图,并通过PN 序列加密来保证水印的
安全性。算法中,将灰度图像转换为二进制数据
流,置乱后扩频调制,隐藏在宿主DCT 系数量化值
中,提取时不需要宿主信号,实现水印信号的盲提
取。-This algorithm is 24-bit true color pictures of the luminance component of block DCT, quantization DCT coefficients and then use the parity properties of 8-bit grayscale watermark embedding map, and through the PN sequence of encryption to ensure the security of the watermark. Algorithm, the gray image into binary data stream, scrambling after the spread spectrum modulation, hidden in the host DCT coefficient quantization values, the extraction does not require the host signal, the blind watermark extraction. Platform: |
Size: 284672 |
Author:王秀梅 |
Hits:
Description: 给予matlab的JPEG压缩程序，包含原始压缩图片，程序对灰度bmp图片进行JEPG编码，压缩成以0101形式的编码。JPEG编码先把图象色彩RBG变成亮度Y和色度Cr、Cb，它利用人的视觉对色度不敏感的特点，减少一部分色度数据，以达到压缩。 JPEG采取多种编码方式，包含有行程编码(Run Length Coding)和哈夫曼(Huffman)编码，有很高的压缩比。在编码前，先对数据进行分块，离散余弦变换（DCT）及量化，保留能量大的低频信号，丢弃高频信号以达到压缩。-Given to the JPEG compression matlab program, contains the original compressed image, the program of the grayscale bmp picture JEPG encoded, compressed into a 0101 form of encoding. RBG color coded JPEG image into a first luminance Y and chrominance Cr, Cb, which uses the human visual characteristics is not sensitive to the color, reduce the number of color data to achieve compression. Take a variety of JPEG encoding, includes length coding (Run Length Coding) and Huffman (Huffman) coding, a high compression ratio. In the code before the data block, discrete cosine transform (DCT) and quantization, to retain a large low-frequency signal energy, discarding high-frequency signals in order to achieve compression. Platform: |
Size: 175104 |
Author: |
Hits:
Description: 作为信息隐藏的重要分支，数字水印是一种有效的数字产品版权保护和数据安全维护技术。近年来数字水印技术成为了信息安全领域的研究热点，也得到了较大的发展。基于变换域的水印技术是目前研究的热点和重点。本文系统介绍了数字水印的原理和应用方法，概要介绍了数字水印的几种主流算法，并重点研究了一种基于离散余弦变换(DCT)数字图像水印算法，并借助 MATLAB编程工具，实现数字水印的嵌入和提取仿真，以及为测试鲁棒性而对水印图像进行攻击实验。-As an important branch of information hiding, digital watermarking is an effective copyright protection of digital products and data security maintenance technology. In recent years, digital watermarking has become a hot research field of information security, has also been considerable development. Transform domain watermarking technique based on the current research focus and focus. This system describes the principles and applications of digital watermarking methods, an overview of several mainstream digital watermarking algorithms, and focus on a discrete cosine transform (DCT) digital image watermarking, and with the MATLAB programming tools, digital watermark embedding and extraction simulation, as well as test the robustness of the watermark image on the attack experiments. Platform: |
Size: 2048 |
Author:yang cheng |
Hits:
Description: 对图像进行DCT正反变换，可以在matlab里面观察正变换后的数据，达到数据压缩。-DCT pros and transform the image in matlab which observed data is transformed to achieve data compression. Platform: |
Size: 6144 |
Author:后效 |
Hits:
Search - data in image matlab dct