The principle of structured light works based on active stereo perception. 

In principle, it works in such a way that a pre-configured sequence of infrared light is projected at regular intervals onto the observed object. This sequence is subject to deformations caused by the geometric shape of the observed object and is subsequently captured by a camera sensing this deformation of the reflected light. This captured deformed sequence is then analysed and processed into the resulting depth map.

Structured light technique