透视变换 (转)

//透视变换 
int WarpPerspective(IplImage *grey)
{
    IplImage* Img_old = cvCloneImage( grey );

    float fix = 4; 
    float w = (float)Img_old->width + fix;
    float h = (float)Img_old->height + fix;

    CvPoint2D32f src_point[4];
    CvPoint2D32f dst_point[4];

    //设定源观察面，即指定四边形的四个顶点
    src_point[0].x=4;             
    src_point[0].y=105;

    src_point[1].x=285;                    
    src_point[1].y=139;

    src_point[2].x=8; 
    src_point[2].y=8;

    src_point[3].x=289; 
    src_point[3].y=33;

    //设定目标观察面，即指定四边形的四个顶点
    dst_point[0].x=-fix;               
    dst_point[0].y=h;

    dst_point[1].x=w;              
    dst_point[1].y=h;

    dst_point[2].x=-fix;
    dst_point[2].y=-fix;

    dst_point[3].x=w;
    dst_point[3].y=-fix;

    float newm[9];            
    CvMat newM = cvMat( 3, 3, CV_32F, newm );
    //获得透视转换矩阵
    cvWarpPerspectiveQMatrix(src_point,dst_point,&newM);
    //透视转换
    cvWarpPerspective(Img_old,grey,&newM,CV_INTER_LINEAR+CV_WARP_FILL_OUTLIERS, cvScalarAll(0) );

    cvNamedWindow("ImgWarp",1);
cvShowImage("ImgWarp",grey);
cvWaitKey(0);

    cvReleaseImage(&Img_old);
    return 0;
}

//测试投射变换
int Quadrangle(IplImage *grey)
{
    IplImage* src = cvCloneImage( grey );

    float m[6];
    int angle = -15;

    CvMat M = cvMat( 2, 3, CV_32F, m );
    int w = src->width;
    int h = src->height;

    m[0] = (float)(cos(angle*CV_PI/180.));
    m[1] = (float)(sin(angle*CV_PI/180.));
    m[2] = w*0.5f;
    m[3] = -m[1];
    m[4] = m[0];
    m[5] = h*0.5f;

    cvGetQuadrangleSubPix( src, grey, &M);
    return 0;
}