Extended 'example.py' to include OpenCV chessboard calibration

decadenza / DirectStereoRectification

"Rectifying Homographies for Stereo Vision: Analytical Solution for Minimal Distortion": algorithm to compute the optimal rectifying homographies that minimise perspective distortion.

GNU General Public License v3.0

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Extended 'example.py' to include OpenCV chessboard calibration #3

Closed KevinCain closed 2 years ago

KevinCain commented 2 years ago

I've updated example.py to include chessboard calibration from (provided) photos as per this recent issue.

Please don't accept this merge request quite yet as the rectification results aren't usable.

Corner detection and individual camera calibration looks valid: uncomment the imshow lines to see the chessboard detection
It looks like the Principal Points are arbitrarily set at image center

Any suggestions are welcome!

KevinCain commented 2 years ago

While the chessboard detection and calibration looks reasonable, my rectification results with the example code in the branch are bad. I've experimented with additional chessboard calibration in case the trouble was not having enough calibration coverage in Z-depth, but the results are equally unusable.

Are there any glaring errors to identify in the 'example.py' in this branch?

decadenza commented 2 years ago

Hi. I had a quick look. You may want to check the following in your fork:

When using cv2.cornerSubPix here you are not saving its output. These are the refined corner points that you should use for calibration.
You should delete the lines from 114 to 120 and use your values to build Po1 and Po2.

Please note that I have to cancel your pull request. My repository is intended to be only an example of rectification to support our paper on rectification. The full library is soon to be released as separate repository.

Happy to help if you have other questions.

decadenza commented 2 years ago

For full library, including calibration, please go https://github.com/decadenza/SimpleStereo