图像处理 灰度图像直方图

 //计算并获取图像的均匀灰度直方图

    
 //dst表示灰度直方图图像,三通道彩色图像
    
 //nBins表示灰度直方图划分的间隔数
    
 //scalarHistColor表示灰度直方图的颜色
    
 void GrayHist(IplImage* src, IplImage* dst, int nBins, CvScalar scalarHistColor);
    
    
    
    
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 void GrayHist(IplImage* src, IplImage* dst, int nBins, CvScalar scalarHistColor)

    
 {
    
 	if (!src || !dst)
    
 	{
    
 		return;
    
 	}
    
 	if (src->nChannels == 3)
    
 	{
    
 		cvCvtColor(src, src, CV_BGR2GRAY);
    
 	}
    
 	//直方图中单个条形图的长度和高度
    
 	int nWidth = dst->width / nBins;
    
 	int nHeight = 0;
    
 	
    
 	int nSizeArray[] = {nBins};
    
 	float fRangeArray[] = {0, 255};
    
 	float* fRange = fRangeArray;
    
 	CvHistogram* pHistGray = cvCreateHist(1, nSizeArray, CV_HIST_ARRAY, &fRange, 1);
    
 	float fMaxVal;//灰度直方图最大值
    
 	double dVal;
    
 	
    
 	cvCalcHist(&src, pHistGray);//计算灰度直方图
    
 	//cvNormalizeHist(pHistGray, 1.0);//归一化直方图
    
 	//cvThreshHist(pHistGray, 0.01);//阈值化直方图，将小于0.01的剔除
    
 	cvGetMinMaxHistValue(pHistGray, NULL, &fMaxVal);//获取直方图最大值
    
 	//画出灰度直方图
    
 	cvZero(dst);//填充底色
    
 	for(int i = 0; i < nBins; i++)
    
 	{
    
 		dVal = cvQueryHistValue_1D(pHistGray, i);
    
 		nHeight = (dVal / fMaxVal) * dst->height;//计算当前条形图的高度
    
 		//绘制直方图
    
 		cvRectangle(dst, cvPoint(nWidth * i, dst->height - nHeight), 
    
 			cvPoint(nWidth * (i + 1), dst->height), scalarHistColor);
    
 	}
    
 	//绘制阈值线
    
 	//nHeight = (0.01 / fMaxVal) * dst->height;//计算阈值线高度
    
 	//cvLine(dst, cvPoint(0, dst->height - nHeight), cvPoint(dst->width, dst->height - nHeight), CV_RGB(255, 0, 0));
    
 	cvReleaseHist(&pHistGray);
    
 }
    
    
    
    
    代码解释