vs2013+opencv2.4，用hough直线变换提取3条直线，并求出3条直线交点，得到一个三角形ROI区域-vs2013+opencv2.4, with a straight line hough transform to extract three straight, and find the intersection of three straight, to give a triangular region ROI

这是用三角窗设计的FIR低通滤波器,来消除音乐信号的噪声,(This is using triangular window design of FIR low-pass filter, to eliminate the noise of the music signal,)