A very good sample of well using Raspberry Pi to detect perspective depth with simple cameras:

The demonstration is of stereo depth perception, i.e. getting depth information from the different views seen by two cameras spaced a short distance apart. This also makes use of another exciting feature of the Pi Compute Module, which is its support for two cameras (the standard Pi only supports one).

Further idea:
– Maybe possible to use thermosensors(like AMG8833) to have a better result and another dimension