opencv 对hu不变矩的测试程序cvGetHuMoments,opencv第八章第10题

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程序对使用轮廓的hu矩进行测试

如下：

#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：

测试结果为：

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