Is a good learning materials to learn PCA feature extraction, Multivariate least squares fitting method of nonlinear equations, Face Recognition light treatment method.

里面包含多种信号特征提取算法，有短时变换算法，包络特征提取算法，模糊函数算法，包络前沿算法，还有PCA降维等(It contains a variety of signal feature extraction algorithms, including short-time transform algorithm, envelope feature extraction algorithm, fuzzy function algorithm, envelope front algorithm,