第一种:使用指针 image.ptr<uchar>(m)[n])
double d0 = ushort(depth.ptr<ushort>(m)[n]) ;
RGB:
double b0 = rgb.ptr<uchar>(m)[n * 3];
double g0 = rgb.ptr<uchar>(m)[n * 3 + 1];
double r0 = rgb.ptr<uchar>(m)[n * 3 + 2];
第二种:image.at
double d1 = depth.at<ushort>(y1, n);