用opencv写的人脸识别程序，从usb摄像头读取每帧图像，并且识别出图像中的正脸，程序是照着官网上写的，代码比较规范，可以作为2次开发使用-Written with opencv face recognition program, each frame is read from the usb camera, and recognize the positive face in the image, the program is written according to the officia