Correcting lens distortion in 3D measuring systems using fringe projection

In this paper several techniques are described to perform the determination and correction of lens distortion in fringe projection systems for 3D object measurement. A new method to realise distortion determination for projection systems is introduced. It uses a plane surface and the projected fringe pattern as calibration tools and determines simultaneously the distortion of both projector and camera lens within an iterative procedure. The lens distortion calibration is performed in the state of the device "ready for measurement" which avoids errors by a later adjustment. A reduction of distortion errors up to 0.02 pixels in the projector chip and also in the camera chip is possible and leads to considerable improvements in the 3D measurements.