C++ OpenCV直方图比较

直方图比较

对输入的两个图像计算得到直方图H1和H2，归一化到相同的尺度空间，然后可以通过计算H1与H2之间的距离得到两个直方图的相似程度进而比较图像本身的相似程度。

OpenCV 提供了四种比较方法：

Correlation 相关性比较

Chi-Square 卡方比较

Intersection 十字交叉比较

Bhattacharyya 巴氏距离比较

相关API cv::compareHist

代码

#include "opencv2/highgui/highgui.hpp" #include "opencv2/imgproc/imgproc.hpp" #include <iostream> #include <stdio.h> using namespace std; using namespace cv; /** @函数 main */ int main( int argc, char** argv ) { Mat src_base, hsv_base; Mat src_test1, hsv_test1; Mat src_test2, hsv_test2; Mat hsv_half_down; /// 装载三张背景环境不同的图像 if( argc < 4 ) { printf("** Error. Usage: ./compareHist_Demo <image_settings0> <image_setting1> <image_settings2>\n"); return -1; } src_base = imread( argv[1], 1 ); src_test1 = imread( argv[2], 1 ); src_test2 = imread( argv[3], 1 ); /// 转换到 HSV cvtColor( src_base, hsv_base, CV_BGR2HSV ); cvtColor( src_test1, hsv_test1, CV_BGR2HSV ); cvtColor( src_test2, hsv_test2, CV_BGR2HSV ); hsv_half_down = hsv_base( Range( hsv_base.rows/2, hsv_base.rows - 1 ), Range( 0, hsv_base.cols - 1 ) ); /// 对hue通道使用30个bin,对saturatoin通道使用32个bin int h_bins = 50; int s_bins = 60; int histSize[] = { h_bins, s_bins }; // hue的取值范围从0到256, saturation取值范围从0到180 float h_ranges[] = { 0, 256 }; float s_ranges[] = { 0, 180 }; const float* ranges[] = { h_ranges, s_ranges }; // 使用第0和第1通道 int channels[] = { 0, 1 }; /// 直方图 MatND hist_base; MatND hist_half_down; MatND hist_test1; MatND hist_test2; /// 计算HSV图像的直方图 calcHist( &hsv_base, 1, channels, Mat(), hist_base, 2, histSize, ranges, true, false ); normalize( hist_base, hist_base, 0, 1, NORM_MINMAX, -1, Mat() ); calcHist( &hsv_half_down, 1, channels, Mat(), hist_half_down, 2, histSize, ranges, true, false ); normalize( hist_half_down, hist_half_down, 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() ); ///应用不同的直方图对比方法 for( int i = 0; i < 4; i++ ) { int compare_method = i; double base_base = compareHist( hist_base, hist_base, compare_method ); double base_half = compareHist( hist_base, hist_half_down, compare_method ); double base_test1 = compareHist( hist_base, hist_test1, compare_method ); double base_test2 = compareHist( hist_base, hist_test2, compare_method ); printf( " Method [%d] Perfect, Base-Half, Base-Test(1), Base-Test(2) : %f, %f, %f, %f \n", i, base_base, base_half , base_test1, base_test2 ); } printf( "Done \n" ); return 0; }

输出的结果

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