【c++|opencv】二、灰度变换和空间滤波---2.直方图和均衡化

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https://blog.csdn.net/weixin_39190382?type=blog

0. 前言

图像直方图、直方图均衡化

1. 图像直方图

#include <iostream>
#include <opencv2/opencv.hpp>using namespace cv;
using namespace std;int main(){Mat img, img_gray,hist;img = imread("/home/v/home.png");if (img.empty()){cout << "Could not open or find the image" << endl;return -1;}cvtColor(img, img_gray, COLOR_BGR2GRAY);imshow("img gray",img_gray);// 获取图像直方图int histSize = 256;float range[] = { 0, 256 };const float* histRange = { range };calcHist(&img_gray, 1, 0, Mat(), hist, 1, &histSize, &histRange, true, false);// 创建直方图int hist_h = 300;int hist_w = 512;int bin_w = hist_w / histSize; // 直方图的等级Mat hist_img(hist_h, hist_w, CV_8UC3, Scalar(0, 0, 0));// 绘制并显示直方图normalize(hist, hist, 0, hist_h, NORM_MINMAX, -1, Mat()); // 归一化直方图for (int i=1;i<histSize;i++){line(hist_img, Point(bin_w*(i-1), hist_h - cvRound(hist.at<float>(i-1))),Point(bin_w*(i), hist_h - cvRound(hist.at<float>(i))),Scalar(0, 0, 255), 2, 8, 0);}imshow("直方图",hist_img);waitKey(0);return 0;
}

2. 直方图均衡化

#include<iostream>
#include<opencv2/opencv.hpp>using namespace cv;
using namespace std;int main(){Mat img,img_gray,img_enhanced;img = imread("/home/v/home.png");if (img.empty()){cout<<"Error"<<endl;return -1;}cvtColor(img,img_gray,COLOR_BGR2GRAY);imshow("gray",img_gray);equalizeHist(img_gray,img_enhanced); // 直方图均衡化imshow("enhanced",img_enhanced);waitKey(0);return 0;
}