【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;
}