A new laser-scanning sensing technique for underwater engineering inspection

In this paper, we describe the concept and technique of a laser space-frequencydifference scanning (LSFDS) sensing system for underwater engineering inspection. Based on this technique, 3D data can be sensed directly in a wide view field and the sensing speed is up to the level of μs/point. Also the backscattering problem in underwater surroundings is avoided. Furthermore a new method for 3D information display on a 2D video system is implemented. Given the requirements of fast data processing in real time applications, neurocomputing is applied for computation of 3D positioning of the target points. The experimental results show the possibility of improvement of computing speed through hardware implementation. Finally the potential of the LSFDS technique for machine vision in the application of target finding and measurement is discussed.