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Triangulation

The triangulation principle

The basis for triangulation consists of the triangle formed by a distinct point on the surface of the object, one projector and a camera (Fig. 1). The object-point is illuminated by the projector using a narrow light beam. This point is seen by the camera as a bright spot. The triangle is uniquely defined if the angles a and b and the baseline 'b' are all known. For example the projecting angle a may be determined from the angle of a mirror in the projector. The receiving angle b is determined from the column number of the bright point in the image. The process must be repeated for all points in the scene e.g. 512 rows by 512 columns, amounting to one quarter of a million of points.