A three-dimensional (3D) digitizer is a device used in conjunction with a computer or other hardware that is capable of capturing the exact dimensions or surface topography of a real-world object and converting that information into a set of 3D points that can be used to form a digital representation of the object being digitized. There are two basic forms of 3D digitizer, the first being a handheld or contact system in which a physical device is used to mark points on the actual object and the digitizer records the location on request to acquire a point set for the object. The second type of 3D digitizer is called a non-contacting digitizer and can use lasers, white light or even magnetism to scan the surface of an object in 3D and then reconstruct the object within a virtual space. The uses for a 3D digitizer range from computer graphics and animation to engineering and industrial design, to medical and dental imaging and production.
A contacting 3D digitizer can take many forms, but one of the more commonly seen varieties involves a pen at the end of an articulated arm. The tip of the stylus is placed on the surface of the physical object and a button is pressed to send a signal to a computer that measures the location of the pen through the position of the articulated arm, creating a single 3D point within the software. After multiple points are input through the stylus, a 3D designer or the software itself then links the points in polygons, creating a 3D representation of the physical object. More advanced versions of a contacting 3D digitizer do not use an arm; instead they may use a handheld device whose position is tracked and measured with sensors located peripherally around the scanning area. Some digitizers are completely self-contained, using advanced mechanisms inside an independent device to find the exact position of the unit and then wirelessly send information to the digitizing software.
Alternately, a non-contacting 3D digitizer uses methods such as lasers, light, sound or magnetism to scan the surface of an object from a distance so it does not have to be physically touched. One method is to use optical triangulation, in which a narrow strip of laser light is passed over the surface of an object and the reflection of the light is captured by an image sensor that converts the surface outline into a strip of 3D points that are woven together to form a 3D surface. Many of these systems are based on optical information, so a non-contacting 3D digitizer also can sometimes capture the actual color or texture of an object to make a 3D model that looks almost exactly like the real-world object.
A number of fields use a 3D digitizer to gather information. In engineering and manufacturing, it is often used to create models for simulations. High-resolution digitizers can be employed to search surfaces for imperfections or damage. In medical fields, a digitizer can be used to create accurate models so prosthetics can be fitted exactly to a human body. In entertainment, a digitizer can be used to convert small concept models, or even an actor’s face, into 3D objects that can then be animated or used in other media.
