GOBO projection for underwater 3D measurement technique

This paper gives an approach for the application of the principle of GOBO projection for underwater 3D measurement systems based on optical 3D scanners using stereo cameras. The GOBO projection principle is explained and the special challenges of underwater structured light projection using GOBO projection are discussed. The new principle was realized in a laboratory setup where camera and projection unit were placed outside a water tank. Several experiments were performed in order to estimate the necessary measurement conditions and parameters such as exposure time, camera lens apertures, measurement field size, and object distance. Additionally, selected different fringe patterns were applied and analyzed. First measurements were performed using a mobile 3D scanner and a GOBO projection unit.