求信号的斜率，在一个周期内求的，在matlab中实现的，是提取特征时用到的。-Seek the slope of the signal, in a demand cycle, in matlab to implement, is used when extracting features. The body s signals.

matlab中对图形轮廓的特征提取代码，程序实现，-matlab in the graphic outline feature extraction code, program implementation,