Target Distance Selected Through Underwater Imaging Technology To Reproduce Three-dimensional,

3D displaying of underwater images is a new research direction of gate ranged underwater imaging technology. In this paper, a type of circular step advance delay gate ranged system is presented. By using the circular step advance delay synchronous control module to change delay time, water cross-section images at different distances are obtained. The main goal of this article is to reconstruct 3D object and to gain an overall visual effect based on the distance information between images.In the paper, the theory of underwater photoelectric imaging is introduced, the technology of range gated imaging and step advance delay synchronous control involved by the system is analyzed, and the choices of related devices such as laser and CCD are discussed.Because laser light scatters in a shape of horn, the brightness of underwater image distributes asymmetrically with brighter centre and darker around. As a result, the characters of the actual scene are reflected incorrectly. To solve the aforementioned problem, the algorithm of image preprocessing based on the thought of homomorphic filtering is studied in this paper. This algorithm can eliminate differences of intensity on the radial direction. The marching cubes algorithm and the ray casting algorithm are developed to realize 3D displaying of range gated image sequences. For omitting the step of segmenting object, the visual effect of the ray casting algorithm is better than the MC algorithm. At last, the simulation of underwater images acquired by the system proves that the ray casting algorithm is effective.