title: Detect road lanes with android and opencv
body: <p>i have problem with detection road lanes with my phone.
  i wrote some code for road lanes detection, but him not working for me.
  From camera get modifications from normal view to BGR colors and try use GausianBlur and Canny, but i think i not good draw lanes for detection.
  Maybe some people have another idea how detection road lanes with OpenCV?</p>
  
  <pre><code>Mat mYuv = new Mat(height + height / 2, width, CvType.CV_8UC1);
  Mat mRgba = new Mat(height + height / 2, width, CvType.CV_8UC1);
  Mat thresholdImage = new Mat(height + height / 2, width, CvType.CV_8UC1);
  mYuv.put(0, 0, data);
  Imgproc.cvtColor(mYuv, mRgba, Imgproc.COLOR_YUV420p2BGR, 4);
  //convert to grayscale
  Imgproc.cvtColor(mRgba, thresholdImage, Imgproc.COLOR_mRGBA2RGBA, 4);
  // Perform a Gaussian blur (convolving in 5x5 Gaussian) &amp; detect edges
  Imgproc.GaussianBlur(mRgba, mRgba, new Size(5,5), 2.2, 2);
  Imgproc.Canny(mRgba, thresholdImage, VActivity.CANNY_MIN_TRESHOLD, VActivity.CANNY_MAX_THRESHOLD);
  Mat lines = new Mat();
  double rho = 1;
  double theta = Math.PI/180;
  int threshold = 50;
  //do Hough transform to find lanes
  Imgproc.HoughLinesP(thresholdImage, lines, rho, theta, threshold, VActivity.HOUGH_MIN_LINE_LENGTH, VActivity.HOUGH_MAX_LINE_GAP);
  for (int x = 0; x &lt; lines.cols() &amp;&amp; x &lt; 1; x++){
      double[] vec = lines.get(0, x);
      double x1 = vec[0],
      y1 = vec[1],
      x2 = vec[2],
      y2 = vec[3];
      Point start = new Point(x1, y1);
      Point end = new Point(x2, y2);
      Core.line(mRgba, start, end, new Scalar(255, 0, 0), 3);
  }
  </code></pre>