title: OpenCV Error: Unsupported format or combination of formats
body: <p>I am developing an application in whitch i have to take a picture from camera and after that Detect the Edge Square(Like Document page.) in the picture...After a long searching i found OpenCV library to achieve this, i have succesfully imported the java library for android, But problem is that when i call the method of opencv to detect Square(The method is </p>
  
  <p><strong>Imgproc.findContours(converted, contours,hierarchy,Imgproc.CHAIN_APPROX_SIMPLE,Imgproc.RETR_LIST)</strong>)..it give me the </p>
  
  <p>exception...<strong><em>OpenCV Error:</em></strong> Unsupported format or combination of formats (FindContours support only 8uC1 and 32sC1 images) in _CvContourScanner* cvStartFindContours(void*, CvMemStorage*, int, int, int, CvPoint), file /home/reports/ci/slave/50-SDK/opencv/modules/imgproc/src/contours.cpp, line 196</p>
  
  <p>I am sending u some piece of code-----------------------------------------------------</p>
  
  <p>public void convertImage() {</p>
  
  <pre><code>    Mat ori = new Mat();
      Mat converted = new Mat(200, 200, CvType.CV_8UC1, new Scalar(0));
  
      try {
          ori = Utils.loadResource(MainActivity.this, R.drawable.ic_launcher, Highgui.CV_LOAD_IMAGE_COLOR);
      } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }
  
      Imgproc.cvtColor(ori,  converted, Imgproc.COLOR_RGB2GRAY, 4);  // convert Image to grayscale
      Imgproc.threshold(ori, converted, 50, 250, Imgproc.ADAPTIVE_THRESH_MEAN_C); // threshold the image
  
      List&lt;MatOfPoint&gt; contours = new ArrayList&lt;MatOfPoint&gt;(10);
      Mat hierarchy = new Mat(200, 200, CvType.CV_32FC1, new Scalar(0));
  
      Imgproc.findContours(converted, contours, hierarchy,Imgproc.CHAIN_APPROX_SIMPLE,Imgproc.RETR_LIST);
  
      ImageView frame = (ImageView) findViewById(R.id.imageView1);
  
      Imgproc.cvtColor(converted, converted, Imgproc.COLOR_GRAY2RGBA, 4); // convert Image back to RGB
      Bitmap bmp = Bitmap.createBitmap(converted.cols(), converted.rows(), Bitmap.Config.ARGB_8888);
  
  
  
  
      frame.setImageBitmap(bmp);
      }
  </code></pre>
  
  <p>Any Help will be apreciated------------------
  Thanks in advance</p>