【OpenCV】OpenCV1.0图像直方图



#include "cv.h"
#include "highgui.h"
#include "cxcore.h"

IplImage* histdraw(CvHistogram* hist,float scalex=1,float scaley=1)
{
	float histmax=0;
	cvGetMinMaxHistValue(hist,0,&histmax,0);
	
	IplImage* result=cvCreateImage(cvSize(256*scalex,64*scaley),8,1);
	cvZero(result);
	
	for(int i=0;i<255;i++)
	{
		float cvnowvalue=cvQueryHistValue_1D(hist,i);
		float cvnextvalue=cvQueryHistValue_1D(hist,i+1);
		
		CvPoint pt0=cvPoint(i*scalex,64*scaley);
		CvPoint pt1=cvPoint((i+1)*scalex,64*scaley);
		CvPoint pt2=cvPoint((i+1)*scalex, (1-(cvnextvalue/histmax))*64*scaley);
		CvPoint pt3=cvPoint(i*scalex,(1-(cvnowvalue/histmax))*64*scaley);
		
		
		int numpts=5;
		CvPoint pts[5];
		pts[0]=pt0;pts[1]=pt1;pts[2]=pt2;pts[3]=pt3;pts[4]=pt0;
		
		cvFillConvexPoly(result,pts,numpts,cvScalar(255));
		
		return (result);
	}
}



int main(int argc, char* argv[])
{
	
	IplImage* scr=cvLoadImage("lena.jpg",0);
	cvNamedWindow("win");
	cvShowImage("win",scr);
	cvWaitKey(0);
	
	//直方图创建
	int dims=1;
	int size=256;
	float rang[]={0,255};
	float* rangs[]={rang};
	CvHistogram* hist;
	hist=cvCreateHist(dims,&size,CV_HIST_ARRAY,rangs,1);
	cvClearHist(hist);
	
	
	//彩色图分解为三通道
	IplImage* imgblue=cvCreateImage(cvGetSize(scr),8,1);
	IplImage* imggreen=cvCreateImage(cvGetSize(scr),8,1);
	IplImage* imgred=cvCreateImage(cvGetSize(scr),8,1);
	cvSplit(scr,imgblue,imggreen,imgred,NULL);
	
	//计算直方图
	cvCalcArrHist(&imgblue,hist,0,0);
	IplImage* blue=histdraw(hist);//调用显示函数
	cvClearHist(hist);
	
	cvCalcArrHist(&imggreen,hist,0,0);
	IplImage* green=histdraw(hist);
	cvClearHist(hist);
	
	cvCalcArrHist(&imgred,hist,0,0);
	IplImage* red=histdraw(hist);
	cvClearHist(hist);
	
	cvNamedWindow("b");
	cvNamedWindow("g");
	cvNamedWindow("r");
	
	cvShowImage("b",blue);
	cvShowImage("g",green);
	cvShowImage("r",red);
	cvWaitKey(0);
	
	cvReleaseImage(&scr);
	cvReleaseImage(&blue);
	cvReleaseImage(&green);
	cvReleaseImage(&red);
	cvDestroyWindow("b");
	cvDestroyWindow("g");
	cvDestroyWindow("r");
	
	return 0;
}




#include "cv.h"
#include "highgui.h"
#include "cxcore.h"
  
void FillWhite(IplImage *pImage)  
{  
    cvRectangle(pImage, cvPoint(0, 0), cvPoint(pImage->width, pImage->height), CV_RGB(255, 255, 255), CV_FILLED);  
}  
// 创建灰度图像的直方图  
CvHistogram* CreateGrayImageHist(IplImage **ppImage)  
{  
    int nHistSize = 256;  
    float fRange[] = {0, 255};  //灰度级的范围    
    float *pfRanges[] = {fRange};    
    CvHistogram *pcvHistogram = cvCreateHist(1, &nHistSize, CV_HIST_ARRAY, pfRanges);  
    cvCalcHist(ppImage, pcvHistogram);  
    return pcvHistogram;  
}  
// 根据直方图创建直方图图像  
IplImage* CreateHisogramImage(int nImageWidth, int nScale, int nImageHeight, CvHistogram *pcvHistogram)  
{  
    IplImage *pHistImage = cvCreateImage(cvSize(nImageWidth * nScale, nImageHeight), IPL_DEPTH_8U, 1);  
    FillWhite(pHistImage);  
	
    //统计直方图中的最大直方块  
    float fMaxHistValue = 0;  
    cvGetMinMaxHistValue(pcvHistogram, NULL, &fMaxHistValue, NULL, NULL);  
	
    //分别将每个直方块的值绘制到图中  
    int i;  
    for(i = 0; i < nImageWidth; i++)  
    {  
        float fHistValue = cvQueryHistValue_1D(pcvHistogram, i); //像素为i的直方块大小  
        int nRealHeight = cvRound((fHistValue / fMaxHistValue) * nImageHeight);  //要绘制的高度  
        cvRectangle(pHistImage,  
            cvPoint(i * nScale, nImageHeight - 1),  
            cvPoint((i + 1) * nScale - 1, nImageHeight - nRealHeight),  
            cvScalar(i, 0, 0, 0),   
            CV_FILLED  
			);   
    }  
    return pHistImage;  
}  
int main( int argc, char** argv )  
{     
    const char *pstrWindowsSrcTitle = "原图";  
    const char *pstrWindowsGrayTitle = "灰度图";  
    const char *pstrWindowsHistTitle = "直方图";  
	
    // 从文件中加载原图  
    IplImage *pSrcImage = cvLoadImage("lena.jpg", CV_LOAD_IMAGE_UNCHANGED);  
    IplImage *pGrayImage = cvCreateImage(cvGetSize(pSrcImage), IPL_DEPTH_8U, 1);  
    // 灰度图  
    cvCvtColor(pSrcImage, pGrayImage, CV_BGR2GRAY);  
	
    // 灰度直方图  
    CvHistogram *pcvHistogram = CreateGrayImageHist(&pGrayImage);  
	
    // 创建直方图图像  
    int nHistImageWidth = 255;  
    int nHistImageHeight = 150;  //直方图图像高度  
    int nScale = 2;              
    IplImage *pHistImage = CreateHisogramImage(nHistImageWidth, nScale, nHistImageHeight, pcvHistogram);  
	
    // 显示  
    cvNamedWindow(pstrWindowsSrcTitle, CV_WINDOW_AUTOSIZE);  
    cvNamedWindow(pstrWindowsGrayTitle, CV_WINDOW_AUTOSIZE);  
    cvNamedWindow(pstrWindowsHistTitle, CV_WINDOW_AUTOSIZE);  
    cvShowImage(pstrWindowsSrcTitle, pSrcImage);  
    cvShowImage(pstrWindowsGrayTitle, pGrayImage);  
    cvShowImage(pstrWindowsHistTitle, pHistImage);  
	
	
    cvWaitKey(0);  
	
    cvReleaseHist(&pcvHistogram);  
	
    cvDestroyWindow(pstrWindowsSrcTitle);  
    cvDestroyWindow(pstrWindowsGrayTitle);  
    cvDestroyWindow(pstrWindowsHistTitle);  
    cvReleaseImage(&pSrcImage);  
    cvReleaseImage(&pGrayImage);  
    cvReleaseImage(&pHistImage);  
    return 0;  
}


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