Robert 邊緣檢測算子

http://blog.csdn.net/cay22/article/details/5592316

#include "math.h"
// Robert算子
/*
-----------
| N2 | N3 |
-----------
| N0 | N1 |
-----------
計算公式
        ___________________
       /              2                    2
      / (N0 - N3)   +  (N1 - N2)
  ///

*/
void Robert(BYTE* image0, BYTE* image1, unsigned int w, unsigned int h)
{ 
 int x, y, aR, aG, aB, a;
 long n;
 for(y = 0; y < h -1; ++y)
 {
  for(x = 0; x < w -1; ++x)
  {
   n = (y * w + x) * 4;

   aR = sqrt((double)((image0[n] - image0[n - w * 4 + 4]) * (image0[n] -image0[n - w * 4 + 4]) + 
                          (image0[n + 4] - image0[n - w * 4]) * (image0[n + 4] - image0[n - w * 4])));

   aG = sqrt((double)((image0[n + 1] - image0[n - w * 4 + 4 + 1]) * (image0[n + 1] -image0[n - w * 4 + 4 + 1]) + 
                          (image0[n + 4 + 1] - image0[n - w * 4 + 1]) * (image0[n + 4 + 1] - image0[n - w * 4 + 1])));

   aB = sqrt((double)((image0[n + 2] - image0[n - w * 4 + 4 + 2]) * (image0[n + 2] -image0[n - w * 4 + 4 + 2]) + 
                          (image0[n + 4 + 2] - image0[n - w * 4 + 2]) * (image0[n + 4 + 2] - image0[n - w * 4 + 2])));

   a = aR + aG + aB;

   a = a>255?255:a;
   //生成邊緣掃描結果
   SetPixel(image1,n,a);
  }
 } 
}

原圖：

Robert 邊緣算子檢測圖：