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Is there a way to compute a RANSAC based affine transformation?

asked 2013-01-31 09:56:23 -0500

Ben gravatar image

updated 2013-01-31 10:09:35 -0500

I know of findHomography(), but that computes all kinds of perspective transformations. I'd like to restrict the degrees of freedom to translation, rotation and scale.

There is a method estimateRigidTransform in the video module, but it's not RANSAC based.

Am I missing something?

Or do I have to implement it on my own?

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answered 2013-05-16 07:08:01 -0500

Ben gravatar image

I solved this problem by first finding a homography and then estimating the rigid transform using only the homography's inlier matches.

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That's dangerous... You might get wrong inliers e.g. if you have a degenerated perspective transformation that maps all points to infinity your inlier criterion is basically useless. You must check the homography for sanity (which is non-trivial in practice).

SR gravatar imageSR ( 2013-06-30 16:32:03 -0500 )edit

I know. These degenerated transformations are annoying. But they usually occur in image pairs that don't match anyway. Do you have a better solution?

Ben gravatar imageBen ( 2013-07-01 02:43:41 -0500 )edit

answered 2013-01-31 10:58:00 -0500

Guanta gravatar image

Afaik this doesn't exist, so you need to implement it on your own.

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Asked: 2013-01-31 09:56:23 -0500

Seen: 2,842 times

Last updated: May 16 '13