opencv读取RGB直方图

// text.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "highgui.h"
#include "cv.h"
#include "cxcore.h"
#include <iostream>

//#include <math.h> 

using namespace std;

void main(int argc,char** argv)
{
	IplImage *src = cvLoadImage("de.png",1);
	
	//IplImage *hsv= cvCreateImage(cvGetSize(src),8,3);
	//cvCvtColor(src,hsv,CV_RGB2HSV);

	IplImage* r_plane = cvCreateImage(cvGetSize(src),8,1);
	IplImage* g_plane = cvCreateImage(cvGetSize(src),8,1);
	IplImage* b_plane = cvCreateImage(cvGetSize(src),8,1);
	//IplImage* planes[] = {h_plane,s_plane};
	cvCvtPixToPlane(src,b_plane,g_plane,r_plane,0);//openCV里面的一个函数,可以看作cvSplit是他的宏:#define cvCvtPixToPlane cvSplit 
	                                               //注意顺序为BGR,OpenCV中不管是Windows中Load的还是摄像头取得的都是BGR顺序排列的

	//计算直方图
	//int h_bins = 100,s_bins = 32;
	int hist_size = 100;
	int hist_height = 100;
	float range[] = {0,255};
	float* ranges[] = {range};
	CvHistogram* r_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);
	CvHistogram* g_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);
	CvHistogram* b_hist = cvCreateHist(1,&hist_size,CV_HIST_ARRAY,ranges,1);

	cvCalcHist(&r_plane,r_hist,0,0);
	cvNormalizeHist(r_hist,1.0);
	cvCalcHist(&g_plane,g_hist,0,0);
	cvNormalizeHist(g_hist,1.0);
	cvCalcHist(&b_plane,b_hist,0,0);
	cvNormalizeHist(b_hist,1.0);

	//创建图像绘制直方图
	int scale = 2;
	IplImage* hist_img = cvCreateImage(cvSize(hist_size*scale,hist_height*3),8,3);
	cvZero(hist_img);

	//绘制矩形表示直方图
	float max_valr = 0,max_valg = 0,max_valb = 0;
	cvGetMinMaxHistValue(r_hist,0,&max_valr,0,0);
	cvGetMinMaxHistValue(g_hist,0,&max_valg,0,0);
	cvGetMinMaxHistValue(b_hist,0,&max_valb,0,0);

	for(int i = 0;i<hist_size;i++)
	{
		float bin_val = cvQueryHistValue_1D(r_hist,i);
		int intensity = cvRound(bin_val*hist_height/max_valr);  //int cvRound (double value)对一个double型的数进行四舍五入，并返回一个整型数！
		cvRectangle(hist_img,cvPoint(i*scale,hist_height),cvPoint((i+1)*scale-1,hist_height-intensity),CV_RGB(255,0,0));
	}
	for(int i = 0;i<hist_size;i++)
	{
		float bin_val = cvQueryHistValue_1D(g_hist,i);
		int intensity = cvRound(bin_val*hist_height/max_valg);  //int cvRound (double value)对一个double型的数进行四舍五入，并返回一个整型数！
		cvRectangle(hist_img,cvPoint(i*scale,2*hist_height),cvPoint((i+1)*scale-1,2*hist_height-intensity),CV_RGB(0,255,0));
	}
	for(int i = 0;i<hist_size;i++)
	{
		float bin_val = cvQueryHistValue_1D(b_hist,i);
		int intensity = cvRound(bin_val*hist_height/max_valb);  //int cvRound (double value)对一个double型的数进行四舍五入，并返回一个整型数！
		cvRectangle(hist_img,cvPoint(i*scale,3*hist_height),cvPoint((i+1)*scale-1,3*hist_height-intensity),CV_RGB(0,0,255));
	}

	cvNamedWindow("histogram",1);
	cvShowImage("histogram",hist_img);

	cvNamedWindow("src",1);
	cvShowImage("src",src);
	//cvNamedWindow("hsv",1);
	//cvShowImage("hsv",hsv);
	
	cvWaitKey(0);

		cvDestroyWindow("src");
	cvReleaseImage(&src);
		cvDestroyWindow("r_plane");
	cvReleaseImage(&r_plane);
		cvDestroyWindow("g_plane");
	cvReleaseImage(&r_plane);
		cvDestroyWindow("g_plane");
	cvReleaseImage(&b_plane);
		cvDestroyWindow("b_plane");
	cvReleaseImage(&src);
		cvDestroyWindow("histogram");
	cvReleaseImage(&hist_img);	

}