Calibration of fringe projection systems

Optical methods of 3D form measurement permit the surface coordinates of the object under inspection to be digitized. The x, y, and z-coordinates wanted are computed from measured data by means of a suitable functional model. A number of parameters that enter the computation need to be determined first in a process known as calibration. The fast and accurate solution of the calibration problems is one of the most important problems to be overcome in the development of form measuring systems. The quality of calibration substantially determines the accuracy to which a system can measure coordinates, and the level of acceptance it gains in industry. On the basis of a general geometric model, this article describes calibration methods for measurement systems using projected fringe patterns.