Although the nonprofessional may assume that there are only two types of 3d scanners available, the contact and the non contact, in actual fact there are a wide variety of scanners which work in three dimensions available. As the name suggests, contact scanners work through physical contact, touching the item to be scanned. For robust items this is fine, however for delicate pieces such as historical items etc, physical touch will mean that the item is damaged and remolded.
Non contact scanners which work on a three dimensional basis are much more diverse. They can be separated into two main categories those of active non contact and passive non contact scanners. The main difference between these two types of non contact scanners is the fact that although both function with the emission of light or radiation with the subsequent reflection being utilized to probe the object or environment, the passive type does not emit any type of radiation itself.
3d scanners such as triangulation, time of flight, hand held lasers conoscopic holography, modulated light and structured light all fall under the category of active non contact scanners, whilst photometric systems, silhouette and stereoscopic systems fall into the passive non contact category. Although these scanners all have the benefit of not having physical contact with an object, the main advantage of passive non contact scanners is the price. Since they do not produce their own radiation, the type of equipment used can be significantly less sophisticated, resulting in a greatly reduced overall price.
If you need portable 3d scanning as an option you will need to invest a little more money than a stationary model. Overall, 3d scanners are very diverse in nature. With various advantages and disadvantages according to the group of scanners to which they belong, scanners, which work in three-dimensional forms, offer a new dimension to an old technique. With scanning being useful from medical to computer animation, the future of scanning has only just begun.