绘制直方图

绘制每列灰度和的归一化直方图

int hist_width = actwidth;    //直方图尺寸  

int hist_height = 255;  

IplImage* hist_image = cvCreateImage(cvSize(hist_width,hist_height),8,3);  

for(i =0;i<actwidth;i++)
{  
      for(j =0;j<actheight;j++)
      {  
             gray=((uchar*)(m_Frame2->imageData + m_Frame2->widthStep*j))[i];
             greySum[i]+=gray;
      }
      if(greySum[i]>maxgreySum)
             maxgreySum=greySum[i];
} 
for(int i=0;i<hist_width;i++)
{  
       int nRealHeight = cvRound((greySum[i]  * hist_height/ maxgreySum) );  //要绘制的高度  
       cvRectangle(hist_image,  cvPoint(i,0),  cvPoint(i+1,nRealHeight), CV_RGB(255,255,255));
   
}