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Why are corners not detected in images with chessboard fiducials?

asked 2011-04-26 01:35:52 -0500

Julius gravatar image

updated 2011-05-05 18:39:35 -0500

Using pose_estimator in tod_training for creating a training base, I wonder why sometimes the pose estimation fails. On fat_free_milk from tod kinect training data pose could be estimated on all of its images.

image description

This might also be an OpenCV issue since the underlying cv::findChessboardCorners in OpenCV does not return any corners. How come?

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You might want to reword the question headline. It doesn't read as a question.
Asomerville gravatar image Asomerville  ( 2011-05-05 07:33:43 -0500 )edit
Thanks for your suggestion.
Julius gravatar image Julius  ( 2011-05-05 18:40:01 -0500 )edit

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answered 2011-06-17 10:55:18 -0500

Mac gravatar image

Some things to try:

  1. Bring the object closer; maybe the chessboard is too small.
  2. Mess with the lighting; even with a black-and-white image, things are tricky.
  3. Make sure you're giving OpenCV the correct chessboard size; it wants the number of rows/cols, not the number of corners, IIRC.
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Thanks for the suggestions. Using a larger chessboard seems to be a prospective idea to try next time. It worked in 80% of all test cases, so I think the general configuration was correct. In my case, lighting should not be changed too much. The OpenCV mailing list shows similar issues.
Julius gravatar image Julius  ( 2011-06-21 01:15:52 -0500 )edit
If you think I've answered your question, you should mark it answered. Karma karma karma!
Mac gravatar image Mac  ( 2011-06-21 12:41:12 -0500 )edit
Sorry for the misunderstanding. The chessboard was detected in about 80% of all pictures similar to the one in my question, _WITHOUT_ incorporating your suggestions. I hope I can try whether using your suggestion pushes the success rate to 100%. Need the laboratory though for this.
Julius gravatar image Julius  ( 2011-06-22 05:45:21 -0500 )edit

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Asked: 2011-04-26 01:35:52 -0500

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Last updated: Jun 17 '11