The Kinect sensor used in the Styku scanner emits harmless infrared light, similar to that used in a remote control. It is completely non-invasive and safe to use.
The IR light coming from the sensor does not affect human tissue, and won’t affect people with pacemakers or other medical conditions. It is safe to be exposed to and even look at. Think of it like a flashlight emitting light, just in a wavelength we as humans can’t really see with our eyes. Other devices that use the same kind of light are remote controls, cordless PC mice, baby video monitors, and the Samsung Galaxy S6 smartphone.
For a more technical answer, the sensor is classified as a Class 1 Laser, which is “safe under all conditions of normal use”, and is the safest of all laser classes : https://en.wikipedia.org/wiki/Laser_safety#Class_1