Getting reflectivity from lidar sensor

[pespen]

I am trying to use the Carla lidar sensor to create 2D images from 3D point cloud data(similarly to how Ouster does it), and have so far been successful with the range and intensity images. Ouster also creates what they call Ambient images, where they somehow use the reflectivity that they get from their sensor to create a more life-like image. Is it possible to get this information from Carla? I basically need to know the number of photons over time the sensor registers. See the image for reference

[GruNyv]

Hi, sounds like we are working on pretty similar problems. However, note that the ambient images are not the same as the reflectivity image. The ambient image are created based on the photons coming from other sources than the lidar (the sun), while the reflectivity images are created by using the inverse square law for the intensity. Btw, could I ask you if you have got any realistic results for the intensity image in Carla? From my experience the simulated values are pretty unrealistic for the intensity image you get from the Ouster sensor.

[pespen]

Alright, that makes sense about the reflectivity and ambient images. My images are not as good as the ones from Ouster, I'm not sure if it's because they do more processing or if they just have more data available. Here are some examples of range and intensity.

This is part of my Graduate degree, and my supervisor said that these images are good enough for our purpose. I might try to adjust the values closest to the camera as it is a bit hard to spot objects there

[GruNyv]

Ouster does not project the point cloud from 3D space to 2D as I assume you do here to create the 2D image. Instead they use the values that each pixel in the sensor itself measures, since these are organized into an array of num_channels * width. The range image however contains holes, as they are not able to calculate the range for noisy points, but they still got the intensity and ambient value from the sensor.

[GruNyv]

Btw, if you want we could talk together about this problem on an other platform, since I do not want to talk about all parts of my thesis in public. Could be interesting to get some other input

[pespen]

Sure! Shoot me an email at phespen@stud.ntnu.no, and we can take it from there (probably use Discord or something if that is OK)

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[TzabarDolev]

Hi, Can I ask how did you get the reflectivity and range images from CARLA?

[Blyron]

Hey, currently LIDAR does not support reflectivity it only returns the cloud of points

[Blyron]

I am closing the issue