The LASER technology
The LASER Scanner technology works according to the principle of time of flight (TOF): an infrared LASER diode (the emission TX) is switched on for a very short time. The resulting light pulse illuminates a specific area and is reflected by the illuminated object; the receiver (photodiode RX) gathers then the reflected light. Depending on the distance between the LASER scanner and the illuminated object, the returned light experiences a certain delay, which is measured by a dedicated microprocessor. As the speed of light is well defined (c = 300.000 m/s), the microprocessor can convert the time information (delay) into a distance information.
As light has a speed of c = 300.000 m/s, the measured delay for an object at for example 2 m distance is of about 13ns.
Thanks to a rotating mirror, which deflects the emitted light pulse at different angular positions, a LASER scanner is able to scan a pre-defined surface.
Each side of the mirror allows scanning an area of 96°; therefore, with a real cube, the LASER scanner would scan four times the same area per complete rotation of the mirror.
A specific mirror, with four slightly inclined faces (instead of a real cube), allows also to cover not only one single 2-dimensional plane, but even four slightly inclined planes .
This technology provides a high degree of accuracy in distance measurement and in object detection, a high degree of flexibility and is less sensitive to exterior environmental interferences compared to other standard infrared solutions.
It can fit to several applications (as for example train doors safety, object and building security, profiling, navigation ...) with dedicated softwares.