Undistortion questions

redtedtezza

Hello,

I'm hoping to clear up some lingering confusion about the state of undistortion and rectification of the RGB video stream from an OAK-D PoE. I see conflicting evidence around the place:

Here, it says: Automatically undistorts camera stream if HFOV of the camera is greater than 85°. But the HFOV of the IMX378 is 66-69, depending on the specs you look up. So this would suggest that it doesn't automatically undistort it.
Here, it says: Camera node will automatically undistort still, video and preview streams, while isp stream will be left as is. This would suggest that it does undistort it.
I ran a separate experiment with the script from the above link, with some tweaks to make the resolutions and scales the same and it looks like, contrary to the above page, the ISP and the video streams appear to be identical, and the ISP stream looks very straight all around. This seems to suggest it is undistorted.
Separately, I notice that the coefficients looks really big compared to what seems typical, where they should all be much less than 1, e.g. [[6.445346832275391, -99.16645050048828, 0.0010444159852340817, -0.0007556898635812104, 438.1270446777344, 6.254124641418457, -97.4456787109375, 431.1665954589844]] Any thoughts as to why these are so big?

Thanks for any help!

jakaskerl

redtedtezza Here, it says: Automatically undistorts camera stream if HFOV of the camera is greater than 85°. But the HFOV of the IMX378 is 66-69, depending on the specs you look up. So this would suggest that it doesn't automatically undistort it.

It shouldn't, no. Is the stream undistorted in your case?

redtedtezza Here, it says: Camera node will automatically undistort still, video and preview streams, while isp stream will be left as is. This would suggest that it does undistort it.

ISP stream has no undistortion regardles of the camera specs. The rest do if HFOV is large.

redtedtezza I ran a separate experiment with the script from the above link, with some tweaks to make the resolutions and scales the same and it looks like, contrary to the above page, the ISP and the video streams appear to be identical, and the ISP stream looks very straight all around. This seems to suggest it is undistorted.

Or that the IMX378 you have has very little distortion to begin with.

Coefficients are big, yes. Maybe the flashed data is wrong? Could you send a rectified image?

Thanks,
Jaka