绘制RGB三色直方图

// Test.cpp : 
//

#include "stdafx.h"
#include <highgui.h>
#include <cvaux.h>

int _tmain(int argc, _TCHAR* argv[])
{
IplImage * src = cvLoadImage("1.jpg");
IplImage* gray_plane = cvCreateImage(cvGetSize(src),8,1);
cvCvtColor(src,gray_plane,CV_BGR2GRAY);

int hist_size = 256;    //直方图尺寸
int hist_height = 256;
float range[] = {0,255}; //灰度级的范围
float* ranges[] = {range};

//创建一维直方图，统计图像在[0,255]像素的均匀分布
//CvHistogram* gray_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);
CvHistogram* red_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);
CvHistogram* green_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);
CvHistogram* blue_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);

//计算灰度图像的一维直方图
//cvCalcHist(&gray_plane,gray_hist,0,0);
cvCalcHist(&gray_plane,red_hist,0,0);
cvCalcHist(&gray_plane,green_hist,0,0);
cvCalcHist(&gray_plane,blue_hist,0,0);