A 3-D scanner is a device that identifies, analyzes, collects and draws/displays shapes or three-dimensional models of real-world environments or solid objects. A 3-D scanner enables the capture of geometric shapes and the recreation of the physical appearance of tangible objects, allowing them to be built and displayed on a computer device.
Techopedia explains 3-D Scanner
A 3-D scanner captures the structural and surface design and depth of the scanned object. It can also collect information on the color of the object. The 3-D scanner calculates the distance between its focal views to the object in determining the 3-D coordinates of the entire object/image/surface. Typically, multiple scans of an object in different positions/angels must be taken before an object/environment can be completely captured.
There are two key types of 3-D scanners:
Contact 3-D Scanners: Requires the object to be physically in contact with the scanner in order to probe and record its dimensions.
Non-Contact 3D Scanners: Use ultraviolet radiation, ultrasound waves and radiation that reflects back from the surface of the object and is recorded by the scanner.