opencv23-直方图计算

#include<opencv2\highgui\highgui.hpp>
#include<opencv2\opencv.hpp>
#include<iostream>
#include<math.h>
using namespace std;
using namespace cv;
char *output_title = "output Image";
Mat src, dst;
int main()
{
	src = imread("E:\\vs2015\\opencvstudy\\1.jpg", 1);
	if (src.empty())
	{
		cout << "could not load the src image!" << endl;
		return -1;
	}
	char *input_title = "input Image";
	imshow(input_title, src);

	//分通道显示
	vector<Mat> bgr_planes;
	split(src, bgr_planes);
	/*imshow("single channel demob", bgr_planes[0]);
	imshow("single channel demog", bgr_planes[1]);
	imshow("single channel demor", bgr_planes[2]);*/

	//计算直方图
	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);

	//根据直方图进行多通道图像的输出并归一化
	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));
	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());

	//绘制直方图
	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, 0), 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, 0), 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(output_title, histImage);

	waitKey(0);
	return 0;
}