Tracking camera calibration not progressing

Alex Kushleyev

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_grey camera 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-calibration app.

Alex

tom

@KnightHawk06 You'll also want to add a -f to your voxl-calibrate-camera call for "fisheye"

KnightHawk06

@Alex-Kushleyev

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
                                 }

Alex Kushleyev

@KnightHawk06 , use voxl-calibrare-camera tracking_down_misp_grey <remaining options>

KnightHawk06

@Alex-Kushleyev Thanks! I was able to get to the 2nd calibration panel with the command below but the process became unresponsive a couple times and I had to reboot, I eventually was able to detect the corners in the 2nd panel but am unable to progress.

voxl-calibrate-camera tracking_down_misp_grey -f -s 6x9 -l 0.0254

Alex Kushleyev

@KnightHawk06 , thanks for the details. I am not aware of the calibration app becoming unresponsive - do you have any details about that (at which point did it become unresponsive?). Any info you have on this would help. thank you!

Alex

KnightHawk06

@Alex-Kushleyev The calibration image froze and I was unable to view any camera data in the VOXL portal, I also was unable to ping the device from my desktop until rebooting the device.

I'm still unable to complete the calibration process, are there any logs that I can review to see what's happening? Any other ideas of how I can proceed?

KnightHawk06

@Alex-Kushleyev You had mentioned there are some other things to try that will require rebuilding the voxl-camera-calibration app? I tried increasing ae_desired_msv and misp_gamma to help with the lens shading but I was not able to progress any further through calibration.

KnightHawk06

@Alex-Kushleyev Here is some more information on the calibration process freezing, the camera feed stops updating in the voxl portal.

Alex Kushleyev

@KnightHawk06 , Please try building the calibration app from this branch : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-camera-calibration/-/tree/fisheye-stereo?ref_type=heads

Some time ago i fixed it up to work with fisheye stereo calibration, but also changed one parameter in thresholding to make it more smooth : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-camera-calibration/-/commit/0bce9a25c67e64a229cfcbad4b6ace3a5837ee1b#f221083d30a7ca966318f904682ecf4970341657 -- in threshold.cpp change the number of tiles from 3 to 5, so that the image thresholding is more smooth across the image (even a larger number like 7 should work even better, but i am not sure if i tried).

In the same branch I also slightly reduced the percentage of the windows that needs to be filled up with the checkerboard pattern, so that it is easier to have the calibration accept the pattern.

Another thing to try, to just reduce the cpu load, just temporarily drop the FPS to 15, so that there are not so many frames to process (you can change it in voxl-camera-server.conf)

I am going to take a look again at this soon and potentially integrate these fixes as options to camera calibration app (number of tiles, frame skip, etc)

Alex