颜色空间分布直方图

// 颜色空间分布直方图.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <cv.h>
#include <highgui.h>
#include <iostream>
using namespace std;

int main(int argc, char* argv[])
{
IplImage * src= cvLoadImage("f:\\vc\\cv\\circle.jpg");

IplImage* hsv = cvCreateImage( cvGetSize(src), 8, 3 );
IplImage* h_plane = cvCreateImage( cvGetSize(src), 8, 1 );
IplImage* s_plane = cvCreateImage( cvGetSize(src), 8, 1 );
IplImage* v_plane = cvCreateImage( cvGetSize(src), 8, 1 );
IplImage* planes[] = { h_plane, s_plane };
/** H 分量划分为16个等级，S分量划分为8个等级 */
int h_bins =16, s_bins = 8;
int hist_size[] = {h_bins, s_bins};

/** H 分量的变化范围 */
float h_ranges[] = { 0, 180 };
/** S 分量的变化范围*/
float s_ranges[] = { 0, 2555 };
float* ranges[] = { h_ranges, s_ranges };

/** 输入图像转换到HSV颜色空间 */
cvCvtColor( src, hsv, CV_BGR2HSV );
cvCvtPixToPlane( hsv, h_plane, s_plane, v_plane, 0 );

/** 创建直方图，二维, 每个维度上均分 */
CvHistogram * hist = cvCreateHist( 2, hist_size, CV_HIST_ARRAY, ranges, 1 );
/** 根据H,S两个平面数据统计直方图 */
cvCalcHist( planes, hist, 0, 0 );

/** 获取直方图统计的最大值，用于动态显示直方图 */
float max_value;
cvGetMinMaxHistValue( hist, 0, &max_value, 0, 0 );
printf("%f",max_value);
/** 设置直方图显示图像 */
int height = 240;
int width = (h_bins*s_bins*6);
IplImage* hist_img = cvCreateImage( cvSize(width,height), 8, 3 );
cvZero( hist_img );

/** 用来进行HSV到RGB颜色转换的临时单位图像 */
IplImage * hsv_color = cvCreateImage(cvSize(1,1),8,3);
IplImage * rgb_color = cvCreateImage(cvSize(1,1),8,3);
int bin_w = width / (h_bins * s_bins);
for(int h = 0; h < h_bins; h++)
{
for(int s = 0; s < s_bins; s++)
{
int i = h*s_bins + s;
/** 获得直方图中的统计次数，计算显示在图像中的高度 */
float bin_val = cvQueryHistValue_2D( hist, h, s );
int intensity = cvRound(bin_val*height/max_value);

/** 获得当前直方图代表的颜色，转换成RGB用于绘制 */
cvSet2D(hsv_color,0,0,cvScalar(h*180.f / h_bins,s*255.f/s_bins,255,0));
cvCvtColor(hsv_color,rgb_color,CV_HSV2BGR);
CvScalar color = cvGet2D(rgb_color,0,0);

cvRectangle( hist_img, cvPoint(i*bin_w,height),
cvPoint((i+1)*bin_w,height - intensity),
color, -1, 8, 0 );
}
}
cvNamedWindow( "Source", 1 );
cvShowImage( "Source", src );

cvNamedWindow( "H-S Histogram", 1 );
cvShowImage( "H-S Histogram", hist_img );

cvWaitKey(0);

return 0;
}