Lidar intensity data?

[APOS80]

I can’t find any lidar intensity data in the output.

On iPhone it can be recorded, so it would be good to have in the ply export.

[matlabbe]

APOS80 wrote

On iPhone it [intensity] can be recorded, so it would be good to have in the ply export.

Where did you see that? The depth data returned by ArKit is only "depth", not intensity

[APOS80]

https://youtu.be/G82inYqQNy8?si=HfSFLOpMmcmnU7ir

In this video.

[matlabbe]

In the video the intensity channel doesn't look like with a real lidar. I tried the same app and exported in PTS, on first try I thought there was indeed intensity after opening it in CloudCompare, but the intensity doesn't look right too in my scan. For example, the shadows were influencing the values, which should not!



I looked into the PTS file directly and saw that there was one column with all zeros, and that column was wrongly mapped by default by CloudCompare as the Red channel, so that Blue channel was mapped to intensity (scalar).



So in the video, the "intensity" we see is actually just the blue channel of the RGB camera. The video is then misleading. The intensity channel is actually 0 for all values. One person commented the same thing. I tried with the Lidar Advanced Mode (like the author replied) and the intensity column is still zero.



EDIT: I looked another time at he video and took screenshots to compare. We clearly see that the shadow on the ground is affecting the "intensity" (actually blue channel) values as it should not:


Note also that with lidar intensity, in general there is also a bigger difference between grass and asphalt (as shown in this video):



cheers,
Mathieu

[APOS80]

Okay, got fooled