Question

我正在尝试比较灰度图像中的两个直方图。我正在使用CV_COMP_CHISQR（0.0完美匹配 - 1.0总不匹配）。我将两个直方图归一化为1。但是当我比较直方图时，我得到的结果超过了40.0，这没有任何意义。我不知道是否可能错过了一些步骤或者可能出现了问题。这是代码的快照。

public class Histogram {     
    public static void main(String[] args) throws Exception {

    String baseFilename = ".../imgs/lp.jpg";
    String contrastFilename = ".../imgs/lpUrb.jpg";c/surf_javacv/box_in_scene.png";

    IplImage baseImage = cvLoadImage(baseFilename);
    CvHistogram hist=getHueHistogram(baseImage);

    IplImage contrastImage = cvLoadImage(contrastFilename);
   CvHistogram hist1=getHueHistogram(contrastImage);

   double matchValue=cvCompareHist(hist, hist1, CV_COMP_CHISQR );
   System.out.println(matchValue);
  }


private static CvHistogram getHueHistogram(IplImage image){
if(image==null || image.nChannels()<1) new Exception("Error!");

IplImage greyImage= cvCreateImage(image.cvSize(), image.depth(), 1);    
cvCvtColor(image, greyImage, CV_RGB2GRAY);   

//bins and value-range
int numberOfBins=256;
float minRange= 0f;
float maxRange= 255f;
// Allocate histogram object
int dims = 1;
int[]sizes = new int[]{numberOfBins};
int histType = CV_HIST_ARRAY;
float[] minMax = new  float[]{minRange, maxRange};
float[][] ranges = new float[][]{minMax};
int uniform = 1;
CvHistogram hist = cvCreateHist(dims, sizes, histType, ranges, uniform);
// Compute histogram
int accumulate = 0;
IplImage mask = null;
IplImage[] aux = new IplImage[]{greyImage};

cvCalcHist(aux,hist, accumulate, null);
cvNormalizeHist(hist, 1);

cvGetMinMaxHistValue(hist, minMax, minMax, sizes, sizes);
System.out.println("Min="+minMax[0]); //Less than 0.01
System.out.println("Max="+minMax[1]); //255
return hist;
}
}//CLass end

Answer 1

从书“Learnig OpenCV”：

“对于卡方，低分表示比高分更好的匹配。完美匹配为0，总不匹配无界限（取决于直方图的大小）。”

如果您需要将结果放在段[0,1]中，请使用method = CV_COMP_INTERSECT，其中高分表示匹配良好，低分表示不匹配。如果两个直方图都归一化为1，则完美匹配为1，总不匹配为0。

JavaCv比较2个直方图

1 个答案: