void createAlphaMat(Mat &img)
{
for (int i = 0; i < img.rows; ++i) {
for (int j = 0; j < img.cols; ++j) {
Vec3b& rgba = img.at
//#define UCHAR_MAX 0xff /* maximum unsigned char value */
rgba[0] =0;//对通道1操作
rgba[1] = saturate_cast
rgba[2] = saturate_cast
//rgba[3] = saturate_cast
}
}
}