exa130202

关于利用离散余弦变换DCT的jpeg压缩的matlab源程序，简单实用，也有注释，很好读。(on the use of discrete cosine transform DCT jpeg compression Matlab source, simple and practical, the Notes have a good time.)

对信号进行小波变换，抑制系数小波滤波，采用了硬阈值滤波方法(right signal wavelet transform, wavelet filter coefficients inhibit use of the hard threshold filtering method)

小波变换(wavelet transform，WT)是一种新的变换分析方法，它继承和发展了短时傅立叶变换局部化的思想，同时又克服了窗口大小不随频率变化等缺点，能够提供一个随频率改变的"时间-频率"窗口，是进行信号时频分析和处理的理想工具。它的主要特点是通过变换能够充分突出问题某些方面的特征，能对时间(空间)频率的局部化分析，通过伸缩平移运算对信号(函数)逐步进行多尺度细化，最终达到高频处时间细分，低频处频率细分，能自动适应时频信号分析的要求，从而可聚焦到信号的任意细节，解决了Fourier变换的困难问题，成为继Fourier变换以来在科学方法上的重大突破。(Wavelet transform (WT) is a new transform analysis method. It inherits and develops the idea of localization of short-time Fourier transform and overcomes the shortcomings that window size does not vary with frequency. It can provide a frequency-dependent The Time-Frequency window is ideal for time-frequency analysis and processing of signals. Its main feature is that by transforming some features that can fully highlight some aspects of the problem, the localization of the time (space) frequency can be analyzed, and the signal (function) can be gradually and multi-scale refined by the scaling operation, finally reaching the high frequency Time subdivision, frequency subdivision at low frequencies, can automatically adapt to the requirements of time-frequency signal analysis, which can focus on any details of the signal to solve the difficulties of Fourier transform has become a major breakthrough in the scientific method since Fourier transform.)

此程序用DWT(离散小波变换)实现二维小波变换(discrete wavelet transform )

数字基带传输基带信号，指未经调制的信号。这些信号的特征是其频谱从零频或很低频率开始，占据较宽的频带。 基带信号在传输前，必须经过一些处理或者某些变换（如码型变换、波形和频谱变换）才能送入信道中传输。处理或变换的目的是使信号的特性与信道的传输特性相匹配。 数字基带信号是消息代码的波形表示。表示形式有多种，有单极性、双极性波形，归零和非归零波形，差分波形、多电平波形之分，各自有不同的特点。 研究数字基带信号通过加性高斯白噪声信道的传输，并且假设信道除了叠加高斯噪声外，不会对信号产生其他失真。(matlabSimulation(pulse amplitude modulation) modulation signal in AWGN (additive white Gaussian noise AWGN (Additive White Gaussian Noise)) under the channel bit error rate and bit error rate performance, and compared with the theoretical value.)

本文实现基于贝叶斯(BAYES)阈值的小波(WAVELET)图像去噪算法，相比较其它的小波去噪算法而言，效果非常好(This realization based on Bayesian (BAYES) Threshold the wavelet (WAVELET) image denoising algorithm, compared with other wavelet denoising algorithm, the effect was very good)

本程序是在labview中利用小波变换理论检测回波(This procedure is in the use of wavelet transform theory labview echo detection)

本程序应用小波变换进行电力系统的在线监测。电力系统在线监测中的检测信号含有大量的背景噪声，不便于检测。应用小波变换解决这一问题。程序中应用db3小波对信号进行5层分解，并得出了各层的细节信号与逼近信号。(This procedure based on wavelet transform power-line monitoring system. Online monitoring of power system test signal contains a lot of background noise, not easy to detect. Application of wavelet transform to resolve this problem. Application procedures for db3 wavelet signal decomposition layer 5, and arrive at different levels of detail signal and approximation signal.)

说明：  Curvelet变换是由一种特殊的滤波过程和多尺度脊波变换组合而成：本程序对彩色图像进行了curvelet变换从而实现图像去噪的效果。首先对图像进行子带分解；然后对不同尺度的子带图像采用不同大小的分块；最后对每个分块进行Ridgelet分析。(Curvelet transform is a combination of a special filtering process and multi-scale ridgelet transform. In this program, curvelet transform is applied to color image to achieve the effect of image denoising. First, the image is decomposed into sub-band; then the sub-band images of different scales are divided into different sizes; finally, each sub-band image is analyzed by ridgelet.)

一个图像小波数字水印的matlab代码,利用小波变换，在DC分量上实现自适应编码(An image digital watermarking wavelet matlab code, the use of wavelet transform, the DC component on the realization of adaptive coding)