Structured light 3D scanners project a bright pattern on the subject and to observe the deformation. The pattern may be in one or two dimensions.
Example of a line as a one-dimensional ground. It is projected on the subject using an LCD
Purposes and eco-compatible TVs because of their drop in energy consumption, are said to be \Led\; the acronym of Light-Emitting Diode in English. We will retain all short \diode\.
General principle : a white light colour and form images
When examined closely, each point on the screen is actually composed of three sub-items : the sub-pixels (red, green, blue), each more or less intensely lit.
These points, ......
projector or laser. A slightly offset the projector camera, records his possible deformation. A technique similar to triangulation is used to calculate the distance, and therefore the position of the points representing. Ground sweeps the field of vision in order to save a bunch at a time, information about distances.
Now take the example of a grid or strip-shaped pattern. A camera is used to record the deformations and a complex computer program is used to calculate the distances of the points making up that ground. The complexity is due to the ambiguity. Take a group of vertical stripes sweeping horizontally a topic. In the simplest case, the analysis is based on the presumption that the sequence of bands visible from left right matches the image projected laser in such a way that the image of the band the leftmost is the first laser projection, the following is the second and so on.
In the case of non-triviales targets with holes, some occlusions, rapid depth changes, however, the order is necessarily verified that bands are often hidden and may even appear in a different order, giving rise to an ambiguity in the bands lasers.
This specific problem has recently been resolved by an advanced technology called Multistripe laser Triangulation (MLT). The structured light 3D scanning is still an active area of research, giving rise to a number of publications each year.
The highlight of the structured light 3D scanners is speed. Instead of scanning a point at a time, they scan the entire field of vision at the same time. This limits or eliminates distortion problems related to the movement. Existing systems are able to scan objects in motion in real time. Recently, Song Zhang and Peisen Huang from Stony Brook University have developed a scan on the fly using a digital fringe projection and a modulated phase technique (another structured light method).
This system is able to capture, rebuild and restore the details of objects deforming in time (as a facial expression) at a frequency of 40 frames per second.