Calibration parameters for HD Pro Webcam C920 not automatically detected

[MafteiAlbert-Alexandru]

When using a HD Pro Webcam C920 with the Vision Portal, the calibration parameters are not automatically detected. This happens due to a "mishap" from Logitech who has the same product registered under 3 different product ids:
HD Pro Webcam C920 - 0x82D, C920 PRO HD Webcam - 0x08E5, C920 HD Pro Webcam - 0x0892(Note: I have the one with 0x0892).

For most teams the workaround is obvious: Copying the calibrations, changing the ids, and adding them to teamwebcamcalibrations.xml, but it would be ideal if the other product ids would also be registered in the SDK, in order to avoid confusing rookie teams(especially since it's stated that the SDK has the calibrations parameters for their camera).

[texasdiaz]

Thanks for the feedback. We are aware of the multiple C920 product ID issue, but we're unable to get a straight answer from Logitech regarding the difference in the devices or changes in the optics. We have also been unable to get hands on the device to verify that the calibration in the SDK is valid for all product IDs. The only way to properly verify is to perform the camera calibration process and compare the results.

• https://ftc-docs.firstinspires.org/en/latest/apriltag/vision_portal/apriltag_camera_calibration/apriltag-camera-calibration.html

Are you able to perform this task and provide us with your results?

[MafteiAlbert-Alexandru]

Are you able to perform this task and provide us with your results?

I will to do the calibration and come back with the results.

[MafteiAlbert-Alexandru]

Hello, I've done the calibration.
It wasn't particulary good(since some photos had some screen glare) but here are the parameters:
Fx: 799.495, Fy: 799.495
Cx: 415.298 Cy: 307.494

[texasdiaz]

What resolution did you calibrate the camera at? Each resolution will have different calibration parameters.

[MafteiAlbert-Alexandru]

Oops, forgot to mention. It was 800x600

…

On Thu, Oct 12, 2023, 22:33 Danny Diaz ***@***.***> wrote: What resolution did you calibrate the camera at? Each resolution will have different calibration parameters. — Reply to this email directly, view it on GitHub <#745 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AQOGBNTITUCHKMF4L5MUB63X7BAZ5ANCNFSM6AAAAAA5SYEPSA> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[MafteiAlbert-Alexandru]

Bump

[texasdiaz]

This has been added for consideration for the 9.1 release, currently targeted for January 2024. This issue will remain open until this work has been completed.

[WestsideRobotics]

An FTC team has found another variant, for model "Logi Webcam C920e", with PID 0x08B6.

[BradDGit]

I have a C920 with the PID 0x08B6. I have run through calibrations and here is the data the I got back with comparisons against the existing FTC values.

Resolution	Source	fx	fy	cx	cy
640x480	FTC	622.001f	622.001f	319.803f	241.251f
640x480	My Camera	638.991	638.991	327.391	246.924
800x600	FTC	775.79f	775.79f	400.898f	300.79f
800x600	My Camera	791.489	791.489	400.403	313.946
640x360	FTC	463.566f	463.566f	316.402f	176.412f
640x360	My Camera	477.753	477.753	320.357	181.369
1920x1080	FTC	1385.92f	1385.92f	951.982f	534.084f
1920x1080	My Camera	1439.292	1439.292	947.996	550.08
800x448	FTC	578.272f	578.272f	402.145f	221.506f
800x448	My Camera	601.618	601.618	392.459	225.876
864x480	FTC	626.909f	626.909f	426.007f	236.834f
864x480	My Camera	644.059	644.059	425.96	241.591

I am not that familiar with running the calibration process or interpreting the results so my process may not have been ideal but it looks like my values are somewhat similar to the ones in the FTC files so most likely this PID could just be added as a new PID for the existing values.

I also found an interesting article that discusses the different C920 models.
https://www.streamtechreviews.com/blog/c920-variations

Please let me know if there is additional data I should be trying to get.

[BradDGit]

@texasdiaz

This has been added for consideration for the 9.1 release, currently targeted for January 2024. This issue will remain open until this work has been completed.

Is this still targeted for this month. Will the PID I referenced above also be included?