3D Laser Scanning Systems

3D scanning offers data about an object's shape and appearance and the digital three dimensional models which are obtained can be used in a wide variety of applications: in movies and games industry, industrial design, quality control and inspection, reverse engineering, prototyping, building orthotics and prosthetics and so on.

The 3D scanning using laser is a method which uses the excellent coherent properties of laser beams to obtain, register and then process digital images of objects. For this , a low-power laser beam is used as a light source and the reflected light from the object surface is detected. The laser scanning along or around the object helps forming a three-dimensional recording of the target's surface.

A time-of-flight 3D laser scanner is an active type of scanner which uses laser light to probe the subject. The time-of-flight laser range finder is used by this scanner to find the distance to a surface (which is done by timing and measuring the round-trip time of a pulse of light). A similar type of laser scanner is the triangulation 3D laser scanner which uses the laser light to probe the environment.

The name of this method (triangulation) is due to the fact that the camera, the laser dot and the laser emitter form a triangle. The first triangulation 3D laser scanner was developed in 1978, by the National Research Council of Canada. Another type of scanning 3D laser systems is the hand-held laser, which is based on a triangulation mechanism too (to create a 3D image).

This means that a laser dot or line is projected onto an object from a hand-held device and the distance to the surface is measured using a sensor (which is usually either a position sensitive device or a charge-coupled device).

If the capability of operating over very long distances (kilometers) of the time-of-flight 3D scanners is an advantage, their relatively low accuracy (on the order of millimeters) is their main disadvantage. In case of triangulation range finders, their accuracy is relatively high (on the order of tens of micrometers) and they have a limited range of several meters (exactly the opposite of the first).