圖像和輪廓的比對(hu矩)
(1)hu矩的概念,我也總結了但是我不過多的闡述,因為我也不是太了解,隻知道它具有平移,旋轉,尺度不變性,詳細見别人的這篇blog:http://blog.csdn.net/wrj19860202/article/details/6327094
(2)opencv 的實作——計算hu矩
<1>普通矩和中心矩的計算
Void cvMoments(const CvArr*arr,CvMoments*moments, int binary = 0)
arr:圖像(1-通道或3通道,有COI設定)或者多邊形(點的CvSeq或一族點的向量)
moments:傳回矩陣态度接口的指針
binary(僅對圖像)如果辨別為非0,則所有零像素點被當成零,其它的被看成1.
Double cvGetSpatialMoment(&moment, p, q); //得到普通矩
Double cvGetCentralMoment(&moment, p, q); // 得到中心矩
<2>計算hu矩
Void cvGetHuMoment(CvMoments *moment,CvHuMoments *humoment)
代碼:
IplImage *src = cvCreateImage(cvSize(10,10), 8, 1);
cvZero(src);
for(int yy = 0; yy < 5; yy++)
{
for(int xx = 0; xx < 5; xx++)
{
cvSetReal2D(src, yy, xx, 255);
}
}
double m00, m10, m01;
CvMoments moment;
cvMoments(src, &moment, 2); //第三個像素點非0,則所有的0像素點被當做0,非0像素點被當做1
m00 = cvGetSpatialMoment(&moment, 0, 0); // 得到普通矩
m10 = cvGetSpatialMoment(&moment, 1, 0);
m01 = cvGetSpatialMoment(&moment, 0, 1);
double u20;
u20 = cvGetCentralMoment(&moment, 2, 0); //得到中心矩
CvHuMoments humoment;
cvGetHuMoments(&moment, &humoment);
double hu1 = humoment.hu1; // 得到hu矩
cout << hu1 << endl;
<3>OPENCV還提供了輸入圖像直接進行hu矩比對的函數,傳回的是兩個圖像或輪廓之間hu矩的相似度:
double cvMatchShapes(const void*object1,const void*object2,int method,doubleparameter=0);
計算兩個輪廓之間hu矩相似程度:
#include <iostream>
#include "cv.h"
#include "cxcore.h"
#include "highgui.h"
using namespace std;
CvSeq *getImageContours(CvArr *src)
{
cvThreshold(src, src, 100, 255, CV_THRESH_BINARY);
CvMemStorage * storage = cvCreateMemStorage(0);
CvSeq * contours;
cvFindContours(src, storage, &contours);
return contours;
}
int main()
{
IplImage *src1 = cvLoadImage("", 0);
CvSeq *contours1 = getImageContours(src1); // 得到src1的輪廓
IplImage *src2 = cvLoadImage("", 0);
CvSeq *contours2 = getImageContours(src2);
double result = cvMatchShapes(contours1, contours2, 1); // 根據輸入的圖像或輪廓來計算它們的hu矩的相似度
cout << result << endl;
cvReleaseMemStorage(&contours1->storage);
cvReleaseMemStorage(&contours1->storage);
cvReleaseImage(&src1);
cvReleaseImage(&src2);
return 0;
}
(3)案例:給出了10副圖檔,其中2.jpg和11.jpg非常相似,我們代碼是要實作的在3~11.jgp找到與2.jpg最相似的圖檔。
代碼:
#include <iostream>
#include <string>
#include <sstream>
#include "cv.h"
#include "cxcore.h"
#include "highgui.h"
using namespace std;
int main()
{
IplImage *srcColor = cvLoadImage("E:\\study_opencv_video\\lesson15_3\\2.jpg", 1);
IplImage *src = cvCreateImage(cvGetSize(srcColor), 8, 1);
cvCvtColor(srcColor, src, CV_BGR2GRAY);
if(!src)
{
cout << "No Image Load" << endl;
}
int i;
stringstream ss;
string path;
string str;
IplImage *dst = NULL, *dstColor;
char c[256];
double result, maxResult= 1000 * 256 *256;
IplImage *resultMap = NULL;
for (i = 3; i < 12; i ++)
{
path = "E:\\study_opencv_video\\lesson15_3\\";
ss.clear();
ss << i;
ss >> str;
str += ".jpg";
path += str;
ss.clear();
ss << path;
ss >> c;
dstColor = cvLoadImage(c,1);
dst = cvCreateImage(cvGetSize(dstColor), 8, 1);
cvCvtColor(dstColor, dst, CV_BGR2GRAY);
result = cvMatchShapes(src, dst, 1);
if(maxResult > result)
{
resultMap = cvCreateImage(cvGetSize(dstColor), 8, 3);
maxResult = result;
cvCopy(dstColor, resultMap);
}
}
cvNamedWindow("srcColor", 0);
cvNamedWindow("resultMap",0);
cvShowImage("resultMap", resultMap);
cvShowImage("srcColor", srcColor);
cvWaitKey(0);
cvReleaseImage(&src);
cvReleaseImage(&srcColor);
cvReleaseImage(&dst);
cvReleaseImage(&dstColor);
cvReleaseImage(&resultMap);
cvDestroyWindow("srcColor");
cvDestroyWindow("resultMap");
return 0;
}
作者:小村長 出處:http://blog.csdn.net/lu597203933 歡迎轉載或分享,但請務必聲明文章出處。 (新浪微網誌:小村長zack, 歡迎交流!)