Tracking camera calibration not progressing
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Hello, I tried to calibrate the tracking camera using a 4x7 checkerboard with side lengths of 4 cm. I launched voxl-portal to view the camera calibration overlay. Then I placed the checkerboard in various positions and orientations within the red box overlayed on the tracking camera image. However, the calibration process does not progress. I never receive a green (overlay) box and the process remains at 0%.
What should I do to solve this issue?
Command used:
voxl-calibrate-camera tracking -f -l 0.04 -s 4x7I followed the calibrate camera instructions from here: https://docs.modalai.com/calibrate-cameras/.
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@Troi same issue here but with stereo camera and command:
voxl-calibrate-camera stereo_front -s 6x9 -l 0.030Did you resolve this?
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@plub ,
Can you provide any more details? Are you able to start the camera calibration and view the camera images using
voxl-portal?Are you sure that you are using a correct type of the checkerboard (correct number of corners)?
Alex
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@Alex-Kushleyev What do you mean by "start" the camera calibration? I've used command which i have pasted in previous post. Then i was able to see camera calibrator tool and images from stereo cameras. Red rectangles showed up but when i placed the chessboard inside them, nothings happened. I am using checkerboard recommended by you: 9x6 OpenCV chessboard. I've tried various combinations in front of the camera but calibration didn't started.
thanks for trying to help
Piotr
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@plub , sorry for the delay. By start the calibration, I meant launch the
voxl-calibrate-cameraapp and view the calibration stream via voxl-portal (it seems you have it working).Is it possible for you to paste a video of a screen recording while you are doing the calibration (screen record the voxl-portal stream).
Thank you
Alex
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@Alex-Kushleyev Thanks. Now calibration is starting. Solution is to use 5x6 checkerboard with trimmed in half squares on edges. But even we can do full calibration, it says failed in the end. Re-projection error for stereo calibration ( standalone cameras calibrate fine ) is very high. Any solutions for this?
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@plub , could you please clarify which cameras you are using in the stereo configuration? OV7251?
If the larger pattern was still detected by the procedure but was not accepted as a sample, this means that the pattern took up too little space of the desired area. You need to fill the desired area in each step almost completely, so that the sample is accepted.
Also, is your checkerboard printed on paper and attached to a very flat surface without wrinkles? A poor calibration pattern can lead to poor results.
Can you please post the result of the calibration? intrinsic and extrinsic parameters that are generated by the calibration procedure, even though it fails. Also please share the reprojection errors.
Alex
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Hello, I'm having the same issue with the dual AR0144 1 MP tracking image sensors not progressing in the calibration sequence. I see some dark obscurations in the tracking rectangle and I am able to see the corners being counted but the calibration sequence never progresses.
voxl2:~$ voxl-calibrate-camera tracking_down -s 6x9 -l 0.0254 -d
Waiting for valid pipe...
Please open voxl-portal in a web browser to view the camera calibrator overlay stream
^C
received SIGINT Ctrl-C
done sampling
Exiting Cleanly
waiting to join consumer thread -
Hello @KnightHawk06,
This can happen because of lens shading on the AR0144 camera lens causing the thresholding (in camera calibration app) to not work as expected.
Depending on the version of VOXL2 SDK you are using, there may be also
tracking_down_misp_greycamera stream available, which is the lens shading compensated output for this camera. I believe it should work better for calibration purposes.Can you please try? If that does not help, I can suggest a few other tweaks, but those will require rebuilding the
voxl-camera-calibrationapp.Alex
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@KnightHawk06 You'll also want to add a
-fto yourvoxl-calibrate-cameracall for "fisheye" -
Thanks for the suggestion. I have en_misp enabled and I can see the misp_grey view in the voxl-portal, How do I command voxl-calibrate-camera to use the misp_grey view?
──────────────────────────────────────────────────────────────────────────────── system-image: 1.8.02-M0054-14.1a-perf kernel: #1 SMP PREEMPT Mon Nov 11 22:47:44 UTC 2024 4.19.125 ──────────────────────────────────────────────────────────────────────────────── hw platform: M0054 mach.var: 1.0.1 ──────────────────────────────────────────────────────────────────────────────── voxl-suite: 1.4.3 ────────────────────────────────────────────────────────────────────────────────{ "type": "ar0144", "name": "tracking_down", "enabled": true, "camera_id": 3, "fps": 30, "en_rotate": false, "en_preview": true, "preview_width": 1280, "preview_height": 800, "en_raw_preview": true, "en_misp": true, "misp_width": 1280, "misp_height": 800, "misp_venc_enable": false, "misp_venc_mode": "h264", "misp_venc_br_ctrl": "cqp", "misp_venc_Qfixed": 30, "misp_venc_Qmin": 15, "misp_venc_Qmax": 50, "misp_venc_nPframes": 29, "misp_venc_mbps": 2, "misp_venc_osd": false, "misp_awb": "auto", "misp_gamma": 1, "ae_mode": "lme_msv", "gain_min": 54, "gain_max": 8000, "ae_desired_msv": 60, "exposure_min_us": 20, "exposure_max_us": 12000, "exposure_soft_min_us": 5000, "ae_filter_alpha": 0.600000023841858, "ae_ignore_fraction": 0.20000000298023224, "ae_slope": 0.05000000074505806, "ae_exposure_period": 1, "ae_gain_period": 1 } -
@KnightHawk06 , use voxl-calibrare-camera tracking_down_misp_grey <remaining options>
