M0149 camera refocusing and tuning parameters
-
@Aaky , our team provided feedback that typically we get around 0.6 pixel reprojection error when calibrating AR0144, so this is consistent with your results. At least, it seems that your camera is not performing worse than expected. We do see higher variance in reprojection error when calibrated multiple times (compared to ov7251). This could be due to the convergence criteria of the calibration procedure - we did not do a thorough investigation.
-
@Alex-Kushleyev Okay. Thanks for the feedback. In that case should I increase the reprojection criteria in voxl-camera-calibration package and save the calibration below 0.6 reprojection? Any other suggestions are welcome. I will perform handheld qvio tests also with this calibration. Any specific error I should be looking for in qvio? Like BAD_CAM_CAL?
-
@Aaky , yes you can adjust the threshold, since the threshold was tuned for ov7251. Reprojection error of 0.5 or 0.6 is not going to matter too much.
QVIO will complain about BAD_CAM_CAL if the calibration is REALLY bad, so it probably wont be the case here.
The ultimate metric of QVIO is drift vs distance traveled (and stability), in good feature rich environments it could get as low as few % drift over distance.
-
@Alex-Kushleyev Thanks for your feedback Alex. I got re-projection error of 0.51 on AR0144 and now I have started to test QVIO in indoors. On few instances I got BAD_CAM_CAL while testing handheld. My MSV was around 70 and extrinsic is caliberated correctly as per my UAV's IMU and camera positions. Please look at below image. I didnt got any error other then BAD_CAM_CAL (ofcourse discounting IMU and vibration errors)
As a observation I didnt see odometry drift in QVIO while I roam around and came back to same origin where my odometry said same x,y and z axis to be almost 0.
Even if Quality in above image looks fine, there are good enough points for tracking still why does QVIO report BAD_CAM_CAL? I am aware QVIO is blackbox for everyone but just wanted your analysis.
Also on a very seperate note, I read somewhere on forum there is some work happening on dual camera support for QVIO? Can you provide me any early stage update on same? Even how is the software architecture for dual QVIO instance and fusion?
-
@Aaky ,
I am not sure why QVIO is reporting bad cam cal. Please double check that you entered the camera calibration parameters correctly for QVIO.
In your test image, this is actually not a great scenario for VIO because all the points are roughly in the same location and at the same distance. Try to test in a more feature rich environment and see if the bad camera calibration warning is still there.
Sometimes it is possible that something else is off and the algorithm "thinks" that it is caused by a bad camera calibration. It is trying to provide a solution within a large state space (many parameters) so it could incorrectly estimate some parameter and think the camera calibration is off.
We are not working on a dual QVIO fusion, but we are working on another flavor of VIO algorithm that supports dual cameras.
Alex
-
@Alex-Kushleyev Thanks Alex. Will test this further. Any update over shading correction for corners of AR0144 camera stream as we discussed previously?
-
@Aaky ,
Sorry, there is no update just yet. it is in the queue to experiment with, but we are testing with AR0144 with the same lens shading issues and it seems the performance is good. It could potentially be better with the shading corrected, but it is not a blocking issues at this point, as we understand. Just to be realistic, I would estimate at least a few weeks before I would have something to test for this feature.
Alex
-
@Alex-Kushleyev Thanks for the update. Can you provide me with camera parameters of AR0144 with which you got better results? In my tests I am getting good results in indoors but it fails in outdoors (imagine flat grass land) where in both cases camera is looking 35 degree downwards from horizon and ideally should be able to get some features. My camera reporjection error came out to be 0.51. If you can share any test bench data and parameters with which you tested QVIO with AR0144 will act as good reference point for my development.
Thank you! -
@Aaky , camera calibration parameters are specific to each camera module, so i don't think any other calibration parameters would work for you better than what you have. Does that make sense? Or are you asking about different parameters (please specify).
I will check to see if we can provide reference data sets running QVIO with AR0144
-
@Alex-Kushleyev Alex actually I am asking for voxl-camera-server related parameters for AR0144 and ofcourse not camera calibration parameters. Along with that, like you mentioned even good test datasets recorded by you would be also beneficial with all camera server parameters and maybe qvio server parameters except intrinsic and extrinsic. Let me know.
Thank you!