WPIcal ChArUco 4x4 request and More

[tom131313]

My team bought a Cameron Camera Calibration Board as seen on Chief Delphi that is good for both LimeLight Vision and PhotonVision calibration functions. It's 4x4 ArUco dictionary. I suggest an option be added to WPIcal to support that board.

I have a Calibration Pose Guidance program that can produce a camera calibration video and I could change that program to use 5x5 but I still have the problem of no really good flat board at 5x5.

Also, the documentation says there is a bug in OpenCV for even numbers of squares. I strongly recommend using the current OpenCV version as does the rest of WPILib so that issue isn't a potential problem.

The documentation also refers to the CalibDB that occasionally has bad snapshots. The root cause of that is bad code and I fixed those errors in the code for my conversion of the CalibDB Pose Guidance algorithm to a Java program.

I'm not sure if I successfully completed a camera calibration with WPIcal but there doesn't appear to be any way to review the calibration results. I'd like to see what WPIcal used for its created camera calibration.

[ElliotScher]

When performing the camera calibration, the output JSON is saved to the same directory as the input video.

Regarding ArUco, I am looking further at supporting more dictionaries, keep an eye out in the next couple of WPILib releases for updates to that. In the mean time, I would suggest printing a 5x5 dictionary ChArUco board and taping it to a flat wall for calibration.

Regarding OpenCV, that warning refers to the calib.io board generation rather than the calibration in WPIcal. As I am not sure whether calib.io is using the latest version of opencv, I think the warning is still applicable. I can make it clearer though!