| Compare with the sonar system, laser system has the advantages of high precision, highefficiency and being unacted on the temperature or salinity of seawater in ocean inspection.It has been developed greatly in recent years. But it is not yet a mature inspection techniquebecause of the complicacy of oceanic channel and water-scattering. There are manyproblems to be studied and resolved. The studies of this dissertation are supported by the Natural Science Foundation ofChina under grant number 60272099 《 New method to 3-D imaging with underwater laserrealizable》. In this paper, the work principle and of general developing situation of oceanlidar technique are introduced fist. The author points out that the intense scattering andabsorbing action on light by seawater is the bottleneck to limit the development of oceanlidar. The MC (Monte Carlo) method is adopted finally to be a basal way of study in thispaper after discussing several method of studying the light transmitting in seawater. Based on the theory of photon transmitted in the seawater and the particularity ofunderwater target detecting, we have studied the characters of laser scattering on underwatertarget surface and spatial and temporal characters of oceanic optical channel. Starting fromthe particularity of underwater target detecting, a new model to describe the roughness ofunderwater target surface is presented. Based on this model, we developed the fast arithmetic,which enhanced the computation speed greatly and the precision was also assured. It madedetecting real-time realizable. Basing on the Monte Carlo simulation and Starting from thetheory of photon transmitted in the seawater, we studied how the parameters of water qualityand other systemic parameters affect the light transmitting through seawater at spatial andtemporal region and provided the theoretical sustentation of enhancing the SNR andoperational distance. It is the bases of underwater target detection and recognition and thesea environment inspection.
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