QImage和IplImage的转换（简单方法）

    IplImage *img = cvLoadImage("girl.jpg",1);
    cvConvertImage(img,img,CV_CVTIMG_SWAP_RB);
    const unsigned char *pImg = (unsigned char *)img->imageData;
    frame = new QImage(pImg, img->width, img->height,img->widthStep, QImage::Format_RGB888);