|
|
|
|
|
|
|
|
|
|
Directory of Commercial Providers of this Technology ...
RE Technology Comparison Chart ...
|
Numerous instruments are available that use one form or another of structured-light to measure the geometry of an object. Most use white light, but some use other broadband sources. Perhaps the simplest to understand are those that project a pattern of lines on an object to be digitized. The pattern is distorted by the object’s three-dimensional nature, and the deviation from the original pattern is translated into a surface measurement at each point in the field of view of the instrument. Triangulation is used to calculate the surface data and nearly all systems use CCD cameras for sensing.
Several variations are available including systems that project moire patterns or fringes, structured-color light patterns, and polarized-light interferometry. Specifications and applications greatly overlap, but structured-light systems have two strong advantages compared to laser-based systems: They’re very fast and can digitize hundreds of thousands to millions of points per second - and they don’t use a laser. These two features have resulted in making them strongly favored for digitizing human beings. A wide selection of application-specific instruments is available for digitizing complete human bodies, and for more specialized needs such as faces, teeth, feet, breasts, etc. A few manufacturers of broadband-source systems provide color capability, but laser scanners that provide color information from ancillary video sources, such as those made by Minolta and Cyberware, are also strong contenders in the body-scanning field. On the down-side, broadband-source systems are, in general, somewhat less accurate than laser systems and are for the most part limited to smaller scanning volumes, typically a cubic meter or less. This may not be a strong limitation, however, since scans can be merged to completely cover very large objects, although it may take considerable time and effort to do so.
|
|
||||
