20轮廓-hu不变矩的测试程序

程序对使用轮廓的hu矩进行测试：

#include <cv.h>  
#include <cxcore.h>  
#include <highgui.h>  
#include <cvaux.h>  
#include <iostream>  
#include <string>  
#include <strstream>  
#include <iomanip>  
#include <cmath>  
using namespace std;  

void imRotate(IplImage *src,IplImage *dst,double angle , CvPoint2D32f center,double scale = 1 );  

int main()  
{  
    time_t StartTime = clock();  

    IplImage *src = cvLoadImage("f:\\images\\test1.bmp",CV_LOAD_IMAGE_GRAYSCALE);  
    cvShowImage("src",src);  
    CvMemStorage *storage = cvCreateMemStorage();  
    CvSeq *contour = NULL;  

    CvRNG rng = cvRNG(-1);  
    while(1){  
        double scalar = cvRandReal(&rng)*0.8;  
        if(scalar < 0.3 )  
            continue;  
        double angle = cvRandReal(&rng)*360;  

        IplImage *dst = cvCreateImage(cvSize(src->width,src->height),8,1);  
        imRotate(src,dst,angle,cvPoint2D32f(src->width/2,src->height/2),scalar);  
        cvShowImage("dst",dst);  

        cvThreshold(dst,dst,100,255,CV_THRESH_BINARY);  

        cvFindContours(dst,storage,&contour);  
        CvMoments moments;  
        CvHuMoments huMoments;  
        cvMoments(dst,&moments,1);  
        cvGetHuMoments(&moments, &huMoments);  

        cout<<"("<<setprecision(3)<<dec<<scalar<<")"<<" ";  
        for(int i = 0;i<7;++i){  
            cout<<setiosflags(ios::scientific)<<setprecision(4)<<((double*)&huMoments)[i]<<' ';  
        }  
        cout<<endl;  
        cvReleaseImage(&dst);  
        cvClearSeq(contour);  
        if(cvWaitKey() == 27)  
            break;  
    }  

    time_t EndTime = clock();  
    cout<<double(EndTime - StartTime)/CLOCKS_PER_SEC<<endl;  
}  


void imRotate(IplImage *src, IplImage *dst,double angle , CvPoint2D32f center,double scale)  
{  
    assert(src->width == dst->width && src->height == dst->height &&src->depth == dst->depth &&src->nChannels == dst->nChannels);  
    CvMat *mapMatrix = cvCreateMat(2,3,CV_32FC1);  
    cv2DRotationMatrix(center,angle,scale,mapMatrix); //旋转缩放为仿射变换，此处求变换矩阵  

    cvWarpAffine(src,dst,mapMatrix);  
}  

测试用图为：

结果如下：

不同的缩放加旋转的情况下的hu不变矩

结果发现，对于旋转加缩放的情况下，得到的7个Hu矩中

hu1 的前三位是可以保持不变的( 不变性最好）

hu2~hu7 保证一位不变了