Opencv 图片直方图

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

Mat img1, img2, img3, img_gray, map_x, map_y;

char win1[] = "window1";
char win2[] = "window2";
char win3[] = "window3";
char win4[] = "window4";

int threshold_value = 0;
int max_value = 255;
RNG rng(12345);

int Demo_Histogram();

int index = 0;

//Remap
int Demo_Histogram()
{
　　img1 = imread("D://images//1//9.jpg");
　　if (img1.empty())
　　{
　　　　cout << "could not load image..." << endl;
　　　　return 0;
　　}
　　imshow(win1, img1);

　　vector<Mat> bgr_planes;

　　//把多通道图像分为多个单通道图像
　　split(img1,bgr_planes);
　　//imshow(win2,bgr_planes);
　　int histSize = 256;
　　float range[] = {0,256};

　　const float *histRanges = {range};
　　Mat b_hist, g_hist, r_hist;
　　calcHist(&bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRanges, true, false);
　　calcHist(&bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRanges, true, false);
　　calcHist(&bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRanges, true, false);

　　int hist_h = 400;
　　int hist_w = 512;
　　int bin_w = hist_w / histSize;
　　Mat histImage(hist_w,hist_h,CV_8UC3,Scalar(0,0,0));

　　//归一化处理
　　normalize(b_hist, b_hist, 0, hist_h, NORM_MINMAX, -1, Mat());
　　normalize(g_hist, g_hist, 0, hist_h, NORM_MINMAX, -1, Mat());
　　normalize(r_hist, r_hist, 0, hist_h, NORM_MINMAX, -1, Mat());

　　for (int i=1;i<histSize;i++)
　　{
　　　　line(histImage,
　　　　　　Point((i-1)*bin_w,hist_h-cvRound(b_hist.at<float>(i-1))),
　　　　　　Point((i)*bin_w, hist_h - cvRound(b_hist.at<float>(i))),
　　　　　　Scalar(255,0,2),2,LINE_AA);

　　　　line(histImage,
　　　　　　Point((i - 1)*bin_w, hist_h - cvRound(g_hist.at<float>(i - 1))),
　　　　　　Point((i)*bin_w, hist_h - cvRound(g_hist.at<float>(i))),
　　　　　　Scalar(0, 255, 2), 2, LINE_AA);

　　　　line(histImage,
　　　　　　Point((i - 1)*bin_w, hist_h - cvRound(r_hist.at<float>(i - 1))),
　　　　　　Point((i)*bin_w, hist_h - cvRound(r_hist.at<float>(i))),
　　　　　　Scalar(0, 0, 255), 2, LINE_AA);
　　}

　　imshow(win2, histImage);
　　return 0;
}

 

int main()
{
　　Demo_Histogram();

　　waitKey(0);
　　return 0;
}