学习OpenCV——绘制彩色直方图(HSV2BGR)
2016-04-17 19:49 GarfieldEr007 阅读(787) 评论(0) 编辑 收藏 举报#include <cv.h> #include <highgui.h> #include <iostream> using namespace std; int main( int argc, char** argv ) { IplImage * src= cvLoadImage("D:/2.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, 255 }; 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 ); /** 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);//Round, Floor, Ceil 转换浮点数为整数(cvRound 返回和参数最接近的整数值。 cvFloor 返回不大于参数的最大整数值。cvCeil 返回不小于参数的最小整数值。) /** 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); }
from: http://blog.csdn.net/yangtrees/article/details/7433598