Structured Light
Structured Light scanners use light and patterns to detect a shapes contours and features as any deformation to the pattern expects shows either a peak or a trough on the 3D object, the amount this is offset gives us our depth. These scanners tend to flash these patterns or light very quickly making them NOT suitable for capturing people if their eyes are open.
Open source models use projectors and webcams to calculate depth. Used more within conservation and heritage contexts whereby UV, Laser infrared light or contact scanning would be harmful to the object being scanned.