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Ambiguity between Checkboard pose [closed]

asked 2013-05-21 23:25:04 -0500

Faizan A. gravatar image

Hi, There is an ambiguity between the checkerboard pose in the upright position and the checkerboard pose rotated 180 degrees vertically(upside down). I am using camera_pose_calibration which relies on image_cb_detector for checkerboard detection for calibrating multiple cameras. Holding the checkerboard upright, one of my cameras assumes it to be upside down during calibration. Any suggestions on how to rectify this?

Thanks,

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Closed for the following reason the question is answered, right answer was accepted by Faizan A.
close date 2013-07-16 23:43:32

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answered 2013-06-04 11:09:39 -0500

Miquel Massot gravatar image

For camera calibration you don't need to rotate a lot the chessboard pattern. Just keep it as straight as possible and try to stick it to the edges to properly calculate distorsion parameters, then also put the chessboard in "prespective" to obtain a good skew ratio correction. Rotation of the chessboard pattern is not necessary.

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Actually i am keeping the checkerboard in the upright position but the corners are detected inverted i.e. the upper right corner of the checkerboard is detected in the lower right of the image instead of top left of the image. I just added a simple check which did the trick. Thanks.

Faizan A. gravatar image Faizan A.  ( 2013-06-05 00:26:00 -0500 )edit

You could also use http://www.ros.org/wiki/camera_calibration#Camera_Calibrator and calibrate the cameras in pairs (if you have more than 2)

Miquel Massot gravatar image Miquel Massot  ( 2013-06-05 05:44:28 -0500 )edit

Can this package be used for multiple Kinects?

Athoesen gravatar image Athoesen  ( 2014-01-09 08:58:35 -0500 )edit

Athoesen: I have not used Kinects with this package, but I suppose you can calibrate two kinects as if they were a stereo pair.

Miquel Massot gravatar image Miquel Massot  ( 2014-01-12 03:48:02 -0500 )edit
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answered 2013-06-03 21:31:50 -0500

Faizan A. gravatar image

I just added a simple check in image_cb_detector to remove the ambiguity. Although now the checkerboard can only be detected in the upright position.

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Asked: 2013-05-21 23:25:04 -0500

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Last updated: Jun 04 '13