直方图
重点研究单通道图像直方图生成过程以下是直方图生成代码:#
"cv.h"#
"highgui.h"#
<stdio.h>#
<ctype.h>
( argc, char** argv ){
IplImage *src = 0;
IplImage *histimg = 0;
CvHistogram *hist = 0;
hdims = 50; // 划分HIST个数越高越精确float hranges_arr
= {0,255};float* hranges = hranges_arr;
bin_w; float max_val;
i;
( argc != 2 || (src=cvLoadImage(argv[1], 0)) 
NULL) //强制转为灰度图像
-1;cvNamedWindow( "Histogram", 0 );
cvNamedWindow( "src", CV_WINDOW_AUTOSIZE);
hist = cvCreateHist( 1, &hdims, CV_HIST_ARRAY, &hranges, 1 ); // 计算直方图
histimg = cvCreateImage( cvSize(320,200), 8, 3 );
cvZero( histimg );
cvCalcHist( &src, hist, 0, 0 ); // 计算直方图
cvGetMinMaxHistValue( hist, 0, &max_val, 0, 0 ); // 只找最大值
cvConvertScale( hist->bins,
hist->bins, max_val ? 255. / max_val : 0., 0 ); // 缩放 bin 到区间 [0,255]
cvZero( histimg );
bin_w = histimg->width / hdims; // hdims: 条
个数则 bin_w 为条宽度// 画直方图
for( i = 0; i < hdims; i
){
double val = ( cvGetReal1D(hist->bins,i)*histimg->height/255 );
CvScalar color = CV_RGB(255,255,0); //(hsv2rgb(i*180.f/hdims);
cvRectangle( histimg, cvPo
(i*bin_w,histimg->height),cvPo
((i+1)*bin_w,()(histimg->height - val)),color, 1, 8, 0 );
}
cvShowImage( "src", src);
cvShowImage( "Histogram", histimg );
cvWaitKey(0);
cvDestroyWindow("src");
cvDestroyWindow("Histogram");
cvReleaseImage( &src );
cvReleaseImage( &histimg );
cvReleaseHist ( &hist );
0;}
运行结果:
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