cv1.4

直方图

直方图统计

//main文件
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;

#include "Histogram.h"

int main(){
    cv::Mat image = cv::imread("f:\\Img\\Lena.jpg");
    Histogram h;

    cv::namedWindow("Red");
    cv::namedWindow("Blue");
    cv::namedWindow("Green");
    cv::namedWindow("Original");
    cv::imshow("Original",image);
    cv::imshow("Red",h.getHistogramImage(image,2));
    cv::imshow("Green",h.getHistogramImage(image,1));
    cv::imshow("Blue",h.getHistogramImage(image));

    cv::waitKey(0);
    return 0;
}

Histogram cpp文件

#include "Histogram.h"

Histogram::Histogram() {
    histSize[0] = 256;
    hrangee[0] = 0.0;
    hrangee[1] = 255.0;
    ranges[0] = hrangee;
    channels[0] = 0;
}


cv::Mat Histogram::getHistogram(const cv::Mat& image){
    cv::MatND hist;
    cv::calcHist(&image, 1, channels, cv::Mat(), hist, 1, histSize, ranges);
    return hist;
}


cv::Mat Histogram::getHistogramImage(const cv::Mat& image, int channel){
    std::vector<cv::Mat> planes;
    cv::split(image,planes);
    cv::Scalar color;
    if(planes.size() == 1){
        channel = 0;
        color = cv::Scalar(0,0,0);
    }else{
        color = cv::Scalar(channel==0?255:0, channel==1?255:0, channel==2?255:0);
    }
    cv::MatND hist = getHistogram(planes[channel]);
    double maxVal = 0;
    double minVal = 0;
    cv::minMaxLoc(hist, &minVal, &maxVal, 0, 0);
    cv::Mat histImg(histSize[0], histSize[0], CV_8UC3, cv::Scalar(255,255,255));
    int hpt = static_cast<int>(0.9*histSize[0]);
    for(int h=0; h<histSize[0]-1; h++){
        float binVal = hist.at<float>(h);
        float binVal2 = hist.at<float>(h+1);
        int intensity = static_cast<int>(binVal*hpt/maxVal);
        int intensity2 = static_cast<int>(binVal2*hpt/maxVal);
        cv::line(histImg, cv::Point(h,histSize[0]-intensity),
                cv::Point(h,histSize[0]-intensity2), color);
    }
    return histImg;
}

Histogram头文件

#ifndef HISTOGRAM_H_
#define HISTOGRAM_H_
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
#include <vector>

class Histogram {
private:
    int histSize[1];
    float hrangee[2];
    const float* ranges[1];
    int channels[1];

protected:
    cv::Mat getHistogram(const cv::Mat&);

public:
    Histogram();
    cv::Mat getHistogramImage(const cv::Mat&, int channel = 0);
};

#endif /* HISTOGRAM_H_ */

直方图均衡化

#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;

int main(){
	Mat mat = imread("f:\\img\\changhong.jpg");
    Mat mergeImg;//合并后的图像
    //用来存储各通道图片的向量
    vector<Mat> splitBGR(mat.channels());
    //分割通道，存储到splitBGR中
    split(mat,splitBGR);
    //对各个通道分别进行直方图均衡化
    for(int i=0; i<mat.channels(); i++)
        equalizeHist(splitBGR[i],splitBGR[i]);
    //合并通道
    merge(splitBGR,mergeImg);
	imshow("src",mat);
	imshow("hist",mergeImg);

    cv::waitKey(0);
    return 0;
}