小波变换的一级分解过程是，原始信号分别进行低通、高通滤波，再分别进行二元下抽样，就得到低频、高频（也称为平均、细节）两部分系数；而多级分解则是对上一级分解得到的低频系数再进行小波分解，是一个递归过程。

matlab m文件运用5种不同的梯度增强法进行图像锐化和图像的高通滤波和掩模处理-matlab m files using five different gradient method for image enhancement and image sharpening high-pass filter and mask handling

用MATLAB实现IIF低通和高通滤波器的滤波特性，并让单位取样信号，周期方波信号和周期三角波信号通过IIF，验证IIR的滤波特性-IIF using MATLAB to achieve low-pass and high-pass filters filtering properties, and to allow units sampled signals, cycle square wave signal and the periodic triangular wave signal th

数字图像频域滤波处理，分别进行二阶巴特沃斯(Butterworth)高通、低通滤波器。-Digital image processing frequency domain filtering, respectively second-order Butterworth (Butterworth) high pass, low pass filter.