setup a stereo rig

asked 2014-09-08 14:17:55 -0600

curtis newton gravatar image

updated 2014-09-08 14:25:02 -0600


I built a stereo camera rig, and I wanted to do triangulation (find X(3d) from xL and xR)

but althought I have good features matches, the fundamental matrix gets sometimes right, sometimes out of whack, no matter what algo I use(ransac, 7pts, 8pts, lmds) if I check xL.t() * F * xR, I get sometimes results close to 0 (barely) sometimes way more than 1

so is it possible that becos of my two cameras are parallel ? should I turn them to some focal point, I though about making it variable, but I would have to recalibrate the rig all the time

the other solution, is to use only one camera and to triangulate from consecutive images (robot moving in 3D space)

any advice is welcome

I can provide the code if needed, but I am pretty sure it is not the issue

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Do you use styrofoam to align the cameras? It could be a problem that your cameras move between the different images of your calibration target. It's just a guess but it would be the first thing I'd improve.

FooBar gravatar imageFooBar ( 2014-09-09 01:41:21 -0600 )edit

nop, it is hard plastic. besides, even if the image content does not change and the camera stay put, I get the same issue, even if the features matches are filtered to be consistents

curtis newton gravatar imagecurtis newton ( 2014-09-09 03:48:39 -0600 )edit

The hard plastic and a camera looking straight forward is your problem I think. Probably their field of view is so small that the overlapping range is quite limited and thus finding matches is difficult. I guess using a somewhat ellipse shape should improve result ALOT.

StevenPuttemans gravatar imageStevenPuttemans ( 2014-09-09 08:19:44 -0600 )edit

actually, I find between 60 and 150 matches, I'll try to add some angle to it

curtis newton gravatar imagecurtis newton ( 2014-09-09 11:36:58 -0600 )edit

Could you post some of the image pairs?

FooBar gravatar imageFooBar ( 2014-09-09 11:49:17 -0600 )edit

Hmm weird. 60 matches should do the trick. You sure you have those matches every time?

StevenPuttemans gravatar imageStevenPuttemans ( 2014-09-10 01:17:47 -0600 )edit