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2.2 Projection of white light patterns
The second technology used extensively for human body measurement is based on the projection of light patterns. It comes closer to the solution of the problems described in the previous section. Instead of moving the scanner unit, a light pattern (usually in form of stripes) is projected onto the human body (Figure 6 left). A light sensor (e.g. a digital camera) acquires the scene. The scanning device is composed usually of a pattern projector and a light sensor (Figure 6 center). More complex systems use two or three light sensors. The measurement process is similar to the method of laser scanning: stripes on the surface are measured singularly by using triangulation. Usually, binary coding systems (Figure 6 right) are used to determine the origin of the single stripes; for the increment of the resolution, the projected stripes are additionally shifted. 
Different patterns are employed by the different manufactures. Figure 7 give some examples of possible variations of the classic binary code. 
The major difference to laser scanning is that the acquisition happens in a very short time and that it results in the digitization of entire surface parts. Everything happens in short time period (mostly under one second), so that human bodies can be digitized without problems: the uncontrolled movements of the person are not a problem. However, the field of measurement of such scanning devices is limited, e.g. Capturor of InSpeck4 (Figure 6 center) can measure surfaces with maximal size of half part of the human body (e.g. upper torso). To measure large parts of the human body (e.g. entire head, full body) multiple scanning devices are required.This procedure has the disadvantage, that multiple units cannot be used simultaneously since they interfere with each other's light patterns projections. Practically, this means, that multiple equipments have to be used serially. This implies again an extension of the acquisition time.
The disposition and the number of employed sensors and projectors can vary depending on the human body part to be measured. For example, the face scanner of Breuckmann5 (Figure 8 left) consists of one projector and two cameras that acquires both sides of the face of a person. A second example is the face scanner of IVB Jena6 (Figure 8 center). In this case, a mirror systems is employed to project the light pattern from five directions by using a single projector; five cameras acquire the different scenes. As last example is shown the full body scanner of InSpeck4 (Figure 8 right): the scanner is composed of three pillars, each having two units, each composed of a camera and a projector. 
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