I want to compare two pictures similarity
Code:

```
Mat mat1=Highgui.imread("/mnt/sdcard/91.png");
Mat mat2=Highgui.imread("/mnt/sdcard/92.png");
double distance = Imgproc.compareHist(mat1, mat2, Imgproc.CV_COMP_CORREL); //(this line throws an exception)

```

Exception information:

> 
> 01-30 10:48:20.203: E/AndroidRuntime(3540): Caused by: CvException
>  [org.opencv.core.CvException:
>  /home/andreyk/OpenCV2/trunk/opencv/modules/imgproc/src/histogram.cpp:1387:
>  error: (-215) H1.type() == H2.type() && H1.type() == CV\_32F in
>  function double cv::compareHist(const cv::\_InputArray&, const
>  cv::\_InputArray&, int)
> 
> 
> 

Can anybody help me? How should I solve this?