Android OpenCV Drawing Hough Lines

Question

I am trying to use OpenCV on an android phone to detect lines. I modified the \'Tutorial 1 Basic - 2. Use OpenCV Camera\' sample. I am also using Hough Line Transform as an

Answer 1

You draw the lines to the mIntermediateMat image, but returning mRgba image. That's why you don't see the lines.

The -1000..1000 range for b is correct. HoughLines returns a line angle and distance from zero (a.k.a. rho and theta). To draw them, you need to convert them to two points. The 1000's are the image dimensions, if you would draw to a 2000x2000 image, increase them to 2000 or otherwise the lines will not cross the entire image.

HoughLines is different algorithm from HoughLinesP. HoughLines only finds lines, that cross the entire image. HoughLinesP returns shorter line segments.