OPENCV 中的图像旋转与缩放

在OPENCV中实现图像旋转，可以采用图像的仿射变换形式，下面给出一个样例程序，说明如何实现图像的旋转与缩放。

#include "cv.h"
#include "highgui.h"
#include "math.h"
int main( int argc, char** argv )
{
IplImage* src=0;
IplImage* dst = 0;

/* the first command line parameter must be image file name */
if( argc==2 ) && (src = cvLoadImage(argv[1], -1))!=0)
{
int delta = 1;
int angle = 0;
int opt = 0; // 1： 旋转加缩放
// 0: 仅仅旋转
double factor;

dst = cvCloneImage( src );
cvNamedWindow( "src", 1 );
cvShowImage( "src", src );

for(;;)
{
float m[6];
// Matrix m looks like:
//
// [ m0 m1 m2 ] ===> [ A11 A12 b1 ]
// [ m3 m4 m5 ] [ A21 A22 b2 ]
//
CvMat M = cvMat( 2, 3, CV_32F, m );
int w = src->width;
int h = src->height;
if(opt) // 旋转加缩放
factor = (cos(angle*CV_PI/180.) + 1.0)*2;
else // 仅仅旋转
factor = 1;
m[0] = (float)(factor*cos(-angle*2*CV_PI/180.));
m[1] = (float)(factor*sin(-angle*2*CV_PI/180.));
m[3] = -m[1];
m[4] = m[0];
// 将旋转中心移至图像中间
m[2] = w*0.5f;
m[5] = h*0.5f;
// dst(x,y) = A * src(x,y) + b
cvZero(dst);
cvGetQuadrangleSubPix( src, dst, &M);
cvNamedWindow( "dst", 1 );
cvShowImage( "dst", dst );
if( cvWaitKey(1) == 27 )
break;
angle =(int) (angle + delta) % 360;
} // for-loop
}
return 0;
}