学习OpenCv透视 ch6_ex6_3 Code for perspective transformation

对于透视变换，必须为map_matrix分配一个3x3数组，除了3x3矩阵和三个控点变为四个控点外，透视变化在其他方面与仿射变换完全类似。具体可以参考：点击打开链接

主要用到两个函数WarpPerspective和GetPerspectiveTransform

#include <cv.h>
#include <highgui.h>

int main(int argc, char** argv)
{
   CvPoint2D32f srcQuad[4], dstQuad[4];
   CvMat* warp_matrix = cvCreateMat(3,3,CV_32FC1);
   IplImage *src, *dst;
    if( argc == 2 && ((src=cvLoadImage(argv[1],1)) != 0 ))
    {
   dst = cvCloneImage(src);
   dst->origin = src->origin;
   cvZero(dst);

   srcQuad[0].x = 0;           //src Top left
   srcQuad[0].y = 0;
   srcQuad[1].x = src->width - 1;  //src Top right
   srcQuad[1].y = 0;
   srcQuad[2].x = 0;           //src Bottom left
   srcQuad[2].y = src->height - 1;
   srcQuad[3].x = src->width - 1;  //src Bot right
   srcQuad[3].y = src->height - 1;
      //- - - - - - - - - - - - - -//
   dstQuad[0].x = src->width*0.05;  //dst Top left
   dstQuad[0].y = src->height*0.33;
   dstQuad[1].x = src->width*0.9;  //dst Top right
   dstQuad[1].y = src->height*0.25;
   dstQuad[2].x = src->width*0.2;  //dst Bottom left
   dstQuad[2].y = src->height*0.7;      
   dstQuad[3].x = src->width*0.8;  //dst Bot right
   dstQuad[3].y = src->height*0.9;
	//由四对点计算透射变换矩阵
   cvGetPerspectiveTransform(srcQuad,dstQuad,warp_matrix);
   //对图像进行透视变换                                 
   cvWarpPerspective(src,dst,warp_matrix);
   cvNamedWindow( "Perspective_Warp", 1 );
      cvShowImage( "Perspective_Warp", dst );
      cvWaitKey();
    }
   cvReleaseImage(&dst);
   cvReleaseMat(&warp_matrix);
    return 0;
}