Depth measurement of underwater target based on laser frequency-difference scanning

Underwater 3-D visual technology is one of key technologies in deep sea detection and operation. To acquire underwater depth information of target object is a key point of underwater 3-D visual technology. In this paper, based on active triangular method, we propose a method through laser frequency-difference scanning technology to obtain depth information from 2-D image. We verify the accuracy of the depth information through experiments, which are carried out in air and underwater environments. The results of experiments indicate that the laser difference-frequency scanning technology can get 3-D depth information from 2-D image in high accuracy.