OpenCV学习(十六)之直方图均衡化并画出直方图

布满荆棘的人生 2022-08-06 11:05 147阅读 0赞

实验环境： VS2010 + OpenCV2.4.9.0

#include <iostream>
    #include "opencv2/highgui/highgui.hpp"
    #include "opencv2/imgproc/imgproc.hpp"
    
    using namespace std;
    using namespace cv;
    
    void showHistogram(Mat &src, int bins,char* wndName)
    {
    	int histSize[] = {bins};
    	float range[] = {0,bins};
    	const float* ranges[] = {range};
    	MatND hist;
    	int channels[] = {0};
    
    	calcHist(&src, 1, channels, Mat(), hist, 1, histSize, ranges, true, false);
    
    	double maxVal;    
    	minMaxLoc(hist, 0, &maxVal, 0, 0); 
    	int scale = 2;	//histogram size(width)
    	int histHeight = 256;
    	Mat histImage = Mat::zeros(histHeight,bins * scale,CV_8UC1);
    
    	for(int i = 0; i < bins; i++)
    	{
    		float binVal = hist.at<float>(i);
    		int intensity = cvRound(binVal * histHeight/maxVal);
    		rectangle(histImage,Point(i * scale,histHeight - 1),
    			Point((i + 1)*scale - 1,histHeight - intensity),CV_RGB(255,255,255));
    	}
    
    	namedWindow(wndName,CV_WINDOW_AUTOSIZE);
    	imshow(wndName,histImage);
    }
    
    int main(int argc,char** argv)
    {
    	Mat src,dst;
    	char* source_window = "Source Image";
    	char* equalized_window = "Equalized Image";
    
    	src = imread("lena.jpg");
    
    	if(!src.data)
    	{
    		cerr << "Read Image Failed!" << endl;
    		exit(1);
    	}
    
    	cvtColor(src,src,CV_BGR2GRAY);
    	equalizeHist(src,dst);
    
    	namedWindow(source_window,CV_WINDOW_AUTOSIZE);
    	imshow(source_window,src);
    
    	namedWindow(equalized_window,CV_WINDOW_AUTOSIZE);
    	imshow(equalized_window,dst);
    
    	//show the histogram
    	int bins = 256;
    	showHistogram(src, bins,"Original Image Hist");
    	showHistogram(dst, bins,"Equalized Image Hist");
    
    	waitKey(0);
    	return 0;
    
    }

实验结果:

原始图像：

![20150115204429716][]

原始直方图：

![20150115204523427][]

直方图均衡化结果：

![20150115204552443][]

均衡化后的直方图：

![20150115204613066][]

[20150115204429716]: /images/20220806/ff11938c06204dcbad92b1c6ab5703f3.png
[20150115204523427]: /images/20220806/2411b83be28a4905a3942611bfcf9b3c.png
[20150115204552443]: /images/20220806/269ebf29e6cd4906a8fd4dcd34c7ff9b.png
[20150115204613066]: /images/20220806/ed8f556009f64310a1b8dbd7f9b59f5c.png