直方图比较

秒速五厘米 2022-04-23 07:20 259阅读 0赞

## 原理 ##

*  如何对两个直方图进行比较，通过一种度量方法来判断两个直方图的相似程度。

两个直方图： H 1 H 2 H\_1 H\_2 H1H2，规定  d ( H 1 , H 2 ) d(H\_1,H\_2) d(H1,H2)他们之间的匹配程度，OpenCV给出了[几种方法][Link 1]：

1.  Correlation ( CV\_COMP\_CORREL )

![在这里插入图片描述][20190124203648637.png]

1.  Chi-Square ( CV\_COMP\_CHISQR )

![在这里插入图片描述][20190124203827871.png]

1.  Intersection ( method=CV\_COMP\_INTERSECT )

![在这里插入图片描述][20190124203850338.png]

1.  Bhattacharyya distance ( CV\_COMP\_BHATTACHARYYA )

![在这里插入图片描述][20190124203911925.png]

1.  。。。。。
2.  。。。。。

--------------------

## 代码 ##

官网代码

#include <opencv2/opencv.hpp>
    #include <iostream>
    
    using namespace cv;
    using namespace std;
    
    
    
    int main(void)
    { 
        Mat src_base = imread("../res/base_0.jpg");
        Mat src_test1 = imread("../res/test_1.jpg");
        Mat src_test2 = imread("../res/test_2.jpg");
    
        if(src_base.empty() || src_test1.empty() || src_test2.empty())
        { 
    	cout << "image fails" << endl;
    	return -1;
        }
    
        Mat hsv_base, hsv_test1,hsv_test2;
        cvtColor(src_base,hsv_base,cv::COLOR_BGR2HSV);
        cvtColor(src_test1,hsv_test1,cv::COLOR_BGR2HSV);
        cvtColor(src_test2,hsv_test2,cv::COLOR_BGR2HSV);
    
    //将hsv_base的下半部分复制给hsv_half_down
        Mat hsv_half_down = hsv_base(Range(hsv_base.rows/2,hsv_base.rows),Range(0,hsv_base.cols));
    
    
        int channels[]={ 0,1};  
    
        int h_bins = 50, s_bins = 60;
        int histSize[]={ h_bins,s_bins};
    
        float h_ranges[] = { 0,180};
        float s_ranges[] = { 0,256};
        const float* ranges[]={ h_ranges,s_ranges};
    
        Mat hist_base, hist_half_dowm, hist_test1, hist_test2;
    
        calcHist(&hsv_base,1,channels,Mat(),hist_base,2,histSize,ranges,true,false);
        normalize(hist_base,hist_base,0,1,NORM_MINMAX,-1,Mat());  //归一化到0-1之间
    
        calcHist(&hsv_half_down,1,channels,Mat(),hist_half_dowm,2,histSize,ranges,true,false);
        normalize(hist_half_dowm,hist_half_dowm,0,1,NORM_MINMAX,-1,Mat());
    	
        calcHist(&hsv_test1,1,channels,Mat(),hist_test1,2,histSize,ranges,true,false);
        normalize(hist_test1,hist_test1,0,1,NORM_MINMAX,-1,Mat());
    
        calcHist(&hsv_test2,1,channels,Mat(),hist_test2,2,histSize,ranges,true,false);
        normalize(hist_test2,hist_test2,0,1,NORM_MINMAX,-1,Mat());
    
    
        for(int compare_method=0; compare_method<4;compare_method++)
        { 
    	double base_base = compareHist(hist_base,hist_base,compare_method);
    	double base_half = compareHist(hist_base,hist_half_dowm,compare_method);
    	double base_test1 = compareHist(hist_base,hist_test1,compare_method);
    	double base_test2 = compareHist(hist_base,hist_test2,compare_method);
    
    	cout << "Method" << compare_method << "Perfect ,Base_half, Base_test1 , Base_test2:"
    	    << base_base << "/" << base_half << "/" << base_test1 << "/" << base_test2 << endl;
    
        }
    
    	return 0;
    };

结果：官网盗的图

![20190124222030628.png][]

![在这里插入图片描述][20190124222206291.png]

[Link 1]: https://docs.opencv.org/master/d6/dc7/group__imgproc__hist.html#ga994f53817d621e2e4228fc646342d386
[20190124203648637.png]: /images/20220323/56e3885a80b340359bcefe5c754bb278.png
[20190124203827871.png]: /images/20220323/efb9d5f1ed3142fab3bf36b318dd607e.png
[20190124203850338.png]: /images/20220323/409c205ed6104c99b08e83b5c5c79f53.png
[20190124203911925.png]: /images/20220323/c2a25911a0d4457b9c79cad563902c4b.png
[20190124222030628.png]: /images/20220323/649050b301354248a5fc36bdb1b19566.png
[20190124222206291.png]: /images/20220323/e3379ffb61544df09d4e259e57c39b50.png