# ToF Sensor Model (w.r.t. unmeasured points)

Source: https://forum.modalai.com/topic/3861/tof-sensor-model-w-r-t-unmeasured-points
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2024-10-11 21:32:24 UTC by Rowan Dempster
Replies: 1 · Views: 526

## Rowan Dempster · 2024-10-11 21:32:24 UTC

When the ToF is looking at empty space, it seems to return that "no measurement" information via a (0,0,0) point value. But when it is looking at occupied space some of the points returned are still "no measurement" points (0,0,0). Is there any way of separating between returns that just never hit something, or points that hit something but the sensor is not confident enough to report a location for?

For the purposes of occupancy mapping it's very useful to know that subtlety of "unknown yes or no the ray hit something" vs. "known empty space along this ray".

## Reply by Moderator (ModalAI staff) · 2024-10-16 04:14:27 UTC

@Rowan-Dempster I think it is safest to just not use data that reads 0,0,0 as the sensor cannot measure that close anyways