title: How to check if obtained homography matrix is good?
body: <p>This question was already <a href="https://stackoverflow.com/questions/11053099/how-can-you-tell-if-a-homography-matrix-is-acceptable-or-not">asked</a>, but I still don't get it. I obtain a homography matrix by calling <code>cv::findHomography</code> from a set of points. I need to check whether it's relevant or not.<br>The proposed method is to calculate maximum reprojection error for inliers and compare it with a threshold. But after such filtration I keep getting insane transformations with object bounding box transforming to almost a straight line or some strange non-convex quadrangle, with self-intersections etc.<br>What constraints can be used to check if the homography matrix itself is adequate?</p>