Most systems for the face reconnaissance are working 2 dimensionally at present. As a rule, video supervisory systems are only two dimensional. Instead of exchanging the existing two dimensional video supervision infrastructure costly, one tries to improve two dimensional face reconnaissance systems. The two-dimensional face reconnaissance has the disadvantage that by use of a photo which is made and stopped in front of the camera by the authorized person the biometric face reconnaissance system can be deceived. It was not even required at older procedures to do the photo in a good quality. Photos of a normal laser printer sufficed for overcomings. Meanwhile is have the two-dimensional procedures been improved so that such an over-listing is no longer so simply possible.
The orientation of the picture of the face as well as the lighting conditions are a problem of the two-dimensional face reconnaissance. Different lighting conditions would go to significant problems from two-dimensional face reconnaissance systems at the person reconnaissance.
Unlike the two dimensional face reconnaissance the three dimensional face reconnaissance uses the shape and form of the face for the reconnaissance. The additional depths and surface information lead to a more to the power of precision of the procedures. Compared with the two dimensional face reconnaissance the three dimensional face reconnaissance has the decisive advantage that the form of the face of the lighting conditions and the orientation is independent. The disadvantage consists in the increased complexity and in the increased price of the recorder. Ausserdem leads the scanning of a three dimensional object holes, since parts of the object covered volumetrically cannot be included and to " ' " ' lead in the surface, be able to these be partly removed by special algorithms, though to inevitable errors.