OpenCV直方图获取的有关问题

代码来源于网上。

#pragma comment(lib, "cv210.lib")
#pragma comment(lib, "cxcore210.lib")
#pragma comment(lib, "highgui210.lib")
#pragma comment(lib, "cvaux210.lib")

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

int main( int argc, char** argv )
{
 IplImage * src;
 if (!(src = cvLoadImage("girl.jpg")))
 {
  cout << "没有找到源文件" << endl;
  return -1;
 }
 
 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, 255 };
 float* ranges[] = { h_ranges, s_ranges };
 
 /** 输入图像转换到HSV颜色空间 */
 cvCvtColor( src, hsv, CV_BGR2HSV );
 cvNamedWindow( "hsv", 1 );
 cvShowImage( "hsv", hsv );
 
 cvCvtPixToPlane( hsv, h_plane, s_plane, v_plane, 0 );
 cvNamedWindow( "h_plane", 1 );
 cvShowImage( "h_plane", h_plane );
 cvNamedWindow( "s_plane", 1 );
 cvShowImage( "s_plane", s_plane );
 cvNamedWindow( "v_plane", 1 );
 cvShowImage( "v_plane", v_plane );
 
 /** 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 );
 
 
 /** 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);
}