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2.1 Laser scanning
Laser scanning technology consists of using lasers to project onto the human body one or more thin and sharp stripes. Simultaneously, light sensors acquire the scene and by applying simple geometrical rules the surface of the human body is measured. To assure the inoffensiveness of the light beam, only eye-safe lasers are used. Special optical systems and mirrors are used for the generation of stripes from a single laser light beam. The laser scanner unit, which is composed of the laser, the optical system and the light sensor, is moved across the human body to digitize the surface. 
The type of movement and the number of employed units can vary depending on the human body part to be measured. For example, the full body scanner of Vitronic1 (Figure 5 left) consists of three scanner units that move vertically synchronously along three pillars. A second example is the head scanner of Cyberware2 (Figure 5 center). In this case, a unique scanner unit moves in circle around the head of a person. As last example is shown the foot scanner of Vorum Research Corp.3: the scanner is composed of three units, which moves horizontally, two laterally and one from the bottom (Figure 5 right). 
The high costs for production of hardware components for the laser scanning technology have to be considered as disadvantage. Additionally to the laser, the light sensor and the optical system, also precise electric motors have to be used for the displacement of the scanner units. Moreover, the complete scanning system has to be calibrated so that the geometrical disposition of all the elements can be determined exactly. A second disadvantage of this method is the time required for the digitization of large surfaces. There is no problem for the measurement of extremities as feet and hands, since these body parts can be kept immobile for some seconds. But, in the case of the measurements of head or full body, it is practical impossible to stay immobile for several seconds. Uncontrolled movements as breathing or muscle contraction can generate errors.
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