#include <cv.h> #include <highgui.h> #pragma comment( lib, "cv.lib" ) #pragma comment( lib, "cxcore.lib" ) #pragma comment( lib, "highgui.lib" ) int main() { IplImage* src=cvLoadImage("lena.jpg",0); int size=256; float range[]={0,255}; float* ranges[]={range}; CvHistogram* hist=cvCreateHist(1,&size,CV_HIST_ARRAY,ranges,1); cvCalcHist(&src,hist,0,NULL); float max=0; cvGetMinMaxHistValue(hist,NULL,&max,NULL,NULL); IplImage* dst=cvCreateImage(cvSize(400,300),8,3); cvSet(dst,cvScalarAll(255),0); double bin_width=(double)dst->width/size; double bin_unith=(double)dst->height/max; for(int i=0;i<size;i++) { CvPoint p0=cvPoint(i*bin_width,dst->height); CvPoint p1=cvPoint((i+1)*bin_width,dst->height-cvGetReal1D(hist->bins,i)*bin_unith); cvRectangle(dst,p0,p1,cvScalar(0,255),-1,8,0); } cvNamedWindow("src",1); cvShowImage("src",src); cvNamedWindow("dst",1); cvShowImage("dst",dst); cvWaitKey(0); cvDestroyAllWindows(); cvReleaseImage(&src); cvReleaseImage(&dst); return 0; }
代码效果如下
可见上面两种方法的结果并无明显的差异。
通过复用上面的代码。我们可以得到彩色图像各通道的直方图，代码如下
#include <cv.h> #include <highgui.h> #pragma comment( lib, "cv.lib" ) #pragma comment( lib, "cxcore.lib" ) #pragma comment( lib, "highgui.lib" ) int main() { IplImage* src=cvLoadImage("lena.jpg",1); IplImage* r=cvCreateImage(cvGetSize(src), IPL_DEPTH_8U, 1); IplImage* g=cvCreateImage(cvGetSize(src), IPL_DEPTH_8U, 1); IplImage* b=cvCreateImage(cvGetSize(src), IPL_DEPTH_8U, 1); cvSplit(src,b,g,r,NULL); IplImage* gray = cvCreateImage(cvGetSize(src),8,1); cvCvtColor(src,gray,CV_BGR2GRAY); int size=256; float range[]={0,255}; float* ranges[]={range}; CvHistogram* r_hist = cvCreateHist(1,&size,CV_HIST_ARRAY,ranges,1); CvHistogram* g_hist = cvCreateHist(1,&size,CV_HIST_ARRAY,ranges,1); CvHistogram* b_hist = cvCreateHist(1,&size,CV_HIST_ARRAY,ranges,1); CvHistogram* hist = cvCreateHist(1,&size,CV_HIST_ARRAY,ranges,1); cvCalcHist(&r,r_hist,0,NULL); IplImage* r_dst=cvCreateImage(cvSize(400,300),8,3); cvSet(r_dst,cvScalarAll(255),0); float r_max=0; cvGetMinMaxHistValue(r_hist,NULL,&r_max,NULL,NULL); double r_bin_width=(double)r_dst->width/size; double r_bin_unith=(double)r_dst->height/r_max; for(int i=0;i<size;i++) { CvPoint p0=cvPoint(i*r_bin_width,r_dst->height); CvPoint p1=cvPoint((i+1)*r_bin_width,r_dst->height-cvGetReal1D(r_hist->bins,i)*r_bin_unith); cvRectangle(r_dst,p0,p1,cvScalar(255,0,0),-1,8,0); } cvCalcHist(&g,g_hist,0,NULL); IplImage* g_dst=cvCreateImage(cvSize(400,300),8,3); cvSet(g_dst,cvScalarAll(255),0); float g_max=0; cvGetMinMaxHistValue(g_hist,NULL,&g_max,NULL,NULL); double g_bin_width=(double)g_dst->width/size; double g_bin_unith=(double)g_dst->height/g_max; for(i=0;i<size;i++) { CvPoint p0=cvPoint(i*g_bin_width,g_dst->height); CvPoint p1=cvPoint((i+1)*g_bin_width,g_dst->height-cvGetReal1D(g_hist->bins,i)*g_bin_unith); cvRectangle(g_dst,p0,p1,cvScalar(0,255,0),-1,8,0); } cvCalcHist(&b,b_hist,0,NULL); IplImage* b_dst=cvCreateImage(cvSize(400,300),8,3); cvSet(b_dst,cvScalarAll(255),0); float b_max=0; cvGetMinMaxHistValue(b_hist,NULL,&b_max,NULL,NULL); double b_bin_width=(double)b_dst->width/size; double b_bin_unith=(double)b_dst->height/b_max; for(i=0;i<size;i++) { CvPoint p0=cvPoint(i*b_bin_width,b_dst->height); CvPoint p1=cvPoint((i+1)*b_bin_width,b_dst->height-cvGetReal1D(b_hist->bins,i)*b_bin_unith); cvRectangle(b_dst,p0,p1,cvScalar(0,0,255),-1,8,0); } cvCalcHist(&gray,hist,0,NULL); IplImage* gray_dst=cvCreateImage(cvSize(400,300),8,3); cvSet(gray_dst,cvScalarAll(255),0); float max=0; cvGetMinMaxHistValue(hist,NULL,&max,NULL,NULL); double bin_width=(double)gray_dst->width/size; double bin_unith=(double)gray_dst->height/max; for(i=0;i<size;i++) { CvPoint p0=cvPoint(i*bin_width,gray_dst->height); CvPoint p1=cvPoint((i+1)*bin_width,gray_dst->height-cvGetReal1D(hist->bins,i)*bin_unith); cvRectangle(gray_dst,p0,p1,cvScalar(0),-1,8,0); } IplImage* dst=cvCreateImage(cvSize(800,600),8,3); cvSetZero(dst); CvRect rect = cvRect(0, 0, 400, 300); cvSetImageROI(dst, rect); cvCopy(r_dst, dst); rect = cvRect(400, 0, 400, 300); cvSetImageROI(dst, rect); cvCopy(g_dst, dst); rect = cvRect(0, 300, 400, 300); cvSetImageROI(dst, rect); cvCopy(b_dst, dst); rect = cvRect(400, 300, 400, 300); cvSetImageROI(dst, rect); cvCopy(gray_dst, dst); cvResetImageROI(dst); cvNamedWindow("src",1); cvShowImage("src",src); cvNamedWindow("dst",1); cvShowImage("dst",dst); cvSaveImage("dst.jpg",dst); cvWaitKey(0); cvDestroyAllWindows(); cvReleaseImage(&src); cvReleaseImage(&dst); cvReleaseImage(&r); cvReleaseImage(&g); cvReleaseImage(&b); cvReleaseImage(&gray); cvReleaseImage(&r_dst); cvReleaseImage(&g_dst); cvReleaseImage(&b_dst); cvReleaseImage(&gray_dst); return 0; }
效果图如下