An Approach for Real-time Display of 3-D Information of Underwater Target

For ROV operations in underwater engineering, it is very important to obtain the depth information among objects. This paper presents a 3D image information display system based on a new technique of laser frequency-difference scanning principle. The depth differences of object surfaces are interpreted as the differences of sensing time of the scanning laser beam and so can be observed on screen in real time. It was verified through experiments in air and in underwater that the system can directly realize the real time estimate of relative depth between targets on a 2D screen.