为什么连接图片不能正常显示

IplImage* matchedimg0=cvCreateImage(cvSize(pFrame10->width+pFrame20->width+band_w,pFrame10->height),IPL_DEPTH_8U,3);
   //cvZero(matchedimg0 );//这一句记得加上去。不然呈现如下效果
   cvSetImageROI(matchedimg0, cvRect( 0, 0, pFrame1->width, pFrame2->height ) );
   cvAdd(pFrame10,matchedimg0,matchedimg0, NULL );
   cvSetImageROI(matchedimg0, cvRect(pFrame10->width+band_w,0, pFrame20->width, pFrame20->height) );
   cvAdd(pFrame2,matchedimg0, matchedimg0, NULL );
   cvResetImageROI( matchedimg0 );