OpenCV 2.4.2 findContours(), how to get only the straight lines contours

Question

When I use from OpenCV 2.4.2 :

cv::findContours()

This is the output :

How can I get rid of all these irregular shapes and leave only straight lines ?

Answer 1

For this case you can use cvMinAreaRect2. this function gives you a CvBox2D, since the contour you want has the biggest Bounding box the larger box is your goal. also this function can help you to find contours around long lines.

Answer 2

You should use HoughLines instead of findContours.