A 3D Scanner is a device used to analyze and collect data on physical objects which can be used to make 3D digital models. It works by creating a cloud of points that replicates the surface of the object under scan. The point cloud is reconstructed into to a 3D CAD model by the 3D Scanning software. 3D Scanners are now used in a variety of industries including medicine, video game, animation, reverse engineering, digital modeling and rapid prototyping.http://www.capture3d.com/knowledge-column.html

3D Scanners can be generally classified into two types: Contact & Non-contact. Contact type 3D Scanners work in physical contact with the scanning object while non-contact type 3D Scanners are to be placed at a certain distance from the scanning object.

Non-contact 3D Scanners can be further divided into two types: Active and Passive scanners. Active scanners work by projecting a laser or some other radiation onto the scanning object and detecting its reflection. Passive scanners work by detecting reflected ambient radiation.

There are several techniques used in 3D Scanners to collect 3D data of the objects. The following are a few commonly used techniques.

1. 3D Laser Scanning
2. White Light Scanning
3. Photogrammetry
4. Destructive Slicing
5. Computed Tomography
6. Trackershttp://www.3dscanco.com/about/3d-scanning/index.cfm

3D Laser Scanners are the most common form of 3D Scanners. It uses a laser and a sensor to collect 3D data. It works by using one or more of the following three techniques:

a) Laser triangulation:

This technique involves the formation of a triangle between the laser source, scanning object and the sensor. It is done by projecting the laser towards the scanning object and collecting its reflection with the sensor. As the reflection angle and the distance between laser source and sensor are known, the x,y and z coordinates of the object can be obtained by trigonometric calculations.

b)Time of flight:

This technique is used for scanning larger areas. In this method, a pulse of laser from laser source is projected towards the object under scan and the reflection is detected by a sensor located close to the laser source. As the speed of laser is known, the distance to the object is calculated by measuring the time elapsed between the emission of the laser and the detection of its reflection. The same process is repeated by projecting the laser towards other areas of the object and the distance is measured as before. With the calculated distances and the horizontal & vertical angles of the laser pulses, the three dimensional coordinates are measured.

1. NextEngine
2. David 3D Scanner
3. Z Corporation