说明：  face detection肤色分割 把彩色图象由rgb彩色空间变换到ycbcr彩色空间，通过算子分割出肤色区域，得到二值图，然后进行膨胀与腐蚀，最后进行边缘检测。
(face detection skin color segmentation to color images from rgb color space conversion into YCbCr color space, through the operator partitions a color region, the binary image, and then expansion and corrosion, and finally to carry out edge detection.)