参数说明：

IplImage *workImg-当前全局变量,表示正在显示的图片。

downleft, upright- 检测出的阴影部分矩形框的两个对角顶点。

  1. /*********************************************/
  2.  //阴影检测
  3. /*********************************************/
  4.  
  5. CvPoint downleft,upright;
  6. int cnt;
  7. ][]={-,-,-,,-,,,,,-,,,,,,-};
  8. #define SHADOW 170
  9. #define Thres_KindNumber 20
  10.  
  11. bool InRange(CvPoint point,IplImage* pi)
  12. {
  13.     int w=pi->width;
  14.     int h=pi->height;
  15.     &&point.x<w&&point.y>=&&point.y<h)
  16.     {
  17.         ];
  18.         ;i<;i++)
  19.         {
  20.             v[i]=((uchar*)(pi->imageData + pi->widthStep*point.y))[point.x*+i];
  21.             if(v[i]<=SHADOW)
  22.                 return true;
  23.         }
  24.     }
  25.     return false;
  26. }
  27.  
  28. void Dye(IplImage** curimg,CvPoint s)
  29. {
  30.     int i;
  31.     queue<CvPoint>Q;
  32.     Q.push(s);
  33.  
  34.     ;i<;i++)
  35.         ((uchar*)((*curimg)->imageData + (*curimg)->widthStep*s.y))[s.x*+i]=SHADOW+;
  36.  
  37.     while(!Q.empty())
  38.     {
  39.         s=Q.front();
  40.         Q.pop();
  41.  
  42.         if(s.x<downleft.x)    downleft.x=s.x;
  43.         if(s.y<downleft.y)    downleft.y=s.y;
  44.         if(s.x>upright.x)    upright.x=s.x;
  45.         if(s.y>upright.y)    upright.y=s.y;
  46.  
  47.         //dye around
  48.         ;i<;i++)
  49.         {
  50.             CvPoint now=cvPoint(s.x+dir[i][],s.y+dir[i][]);
  51.             if(InRange(now,*curimg))
  52.             {
  53.                 Q.push(now);
  54.                 cnt++;
  55.                 ;i<;i++)
  56.                     ((uchar*)((*curimg)->imageData + (*curimg)->widthStep*now.y))[now.x*+i]=SHADOW+;
  57.             }
  58.         }
  59.     }
  60. }
  61.  
  62. void CCVMFCView::OnShadowDetect()
  63. {
  64.     //detect shadows,find the region with highest pixel value
  65.     int x,y;
  66.     srcimg=workImg;
  67.     ;y<srcimg->height;y++)
  68.         ;x<srcimg->width;x++)
  69.         {
  70.             CvPoint curp=cvPoint(x,y);
  71.             downleft.x=srcimg->width;downleft.y=srcimg->height;
  72.             upright.x=upright.y=;
  73.             cnt=;
  74.  
  75.             if(InRange(curp,srcimg))
  76.                 Dye(&srcimg,curp);
  77.             if(cnt>Thres_KindNumber)
  78.                 cvRectangle(workImg , downleft,upright,CV_RGB(,,),,CV_AA,);
  79.         }
  80.         Invalidate();
  81. }

from: http://blog.csdn.net/abcjennifer/article/details/7334043