二维离散余弦变换-矩阵形式 矩阵形式 正变换:F=DfDT; 反变换：f=DTFD; 产生DCT矩阵的MATLAB函数： D=dctmtx(N);

这是一维和二维离散小波变换的 matlab 实现，它是 JPEG2000 图像压缩标准的核心

C#语言、VS2005开发环境，包括二维离散傅里叶变换、快速傅里叶变换、幅度图像与相位图像、频率成分滤波、频率方位变换

正交变换 VS2017编译通过，可直接运行 包括一维傅立叶变换 二维离散余弦变换 沃尔什变换

A new two-dimensional chaotic system in the form of a cascade structure is designed, which is derived from the Chebyshev system and the infinite collapse system. Performance analysis including trajectory, Lyapunov exponent and approximate entropy indicate that it has a larger chaotic range, better ergodicity and more complex chaotic behaviour than those of advanced two-dimensional chaotic system recently proposed. Moreover, to protect the security of the crowd image data, the newly designed two-dimensional chaotic system is utilized to propose a visually meaningful image cryptosystem combined with singular value decomposition and Bernstein polynomial. First, the plain image is compressed by singular value decomposition, and then encrypted to the noise-like cipher image by scrambling and diffusion algorithm. Later, the steganographic image is obtained by randomly embedding the cipher image into a carrier image in spatial domain through the Bernstein polynomial based embedding method, thereby realizing the double security of image information and image appearance. Besides, the visual quality of the steganographic image can be improved by the adjustment factor according to different carrier images during the embedding process. Ultimately, security analyses indicate that it has higher encryption efficiency (2 Mbps) and the visual quality of steganography image can reach 39 dB.

通过matlab实现二维离散傅里叶变换，并与matlab自带的函数计算的结果比较

基于opencv的DWT的实现，代码注释详细，促进学习交流

07二维离散型随机变量.pptx

matlab证明二维离散傅里叶变换、实现二维离散余弦变换、二维沃尔什变换、二维哈达玛变换的实现。自己跑过的，可以使用。

非常方便简单-读取TXT的三列数据画二维等值线图的python代码，用户也可以根据需求稍微修改读取excel或CSV等格式的文件。