What is 3D Scanning

3D scanning refers to a broad range of technologies that bring the physical world into the digital world.  This a broader view than most would give you but I feel it is more appropriate because it encompasses technologies such as:

• Laser Triangulation
• Structured Light
• Computerized Tomography (CT)
• Magnetic Resonance Imaging (MRI)
• Optical Coherence Tomography (OCT)
• Time of Flight
• Geosurvey (Terrestrial Laser Scanning)
• Photogrammetry
• Stereo Vision
• Computer Vision
• Structure from Motion

These technologies are similar in application and the technical skills required to develop them.  I won't go into too much detail on the list above because there are more comprehensive sources such as http://en.wikipedia.org/wiki/3D_scanner.  

I put together a very basic technical description of 3D scanning.