opencv提取ROI区域

#include <highgui.h>
#include <cv.h>
#include <iostream>
using namespace std;
void GetROI(IplImage *src,IplImage *dst,int height,int width)
{
  
 //IplImage *src = cvLoadImage("E:\\3.jpg");
 int srcHeight=src->height;
 int srcWidth=src->width;
 CvRect rect;
 rect.x=(srcWidth-width)/2;
 rect.y=(srcHeight-height)/2;

 if (rect.x<0||rect.y<0)
 {
  cout<<"指定的图像大小越界"<<endl;
  return;
 }
 rect.width= width;
 rect.height=height;

 IplImage *dst=cvCreateImage(cvSize(64,128),src->depth,src->nChannels);

 cvSetImageROI(src,rect);
 cvCopy(src,dst);
 //cvSaveImage("E:\\44.jpg",dst);
 
}