水下连续光成像系统照明光源的最优化波长选择

Optimal Wavelength Selection of Illumination Source for Underwater Continuous Light Imaging System

水下连续光成像系统在海洋探测领域具有广泛的应用,但其成像距离受到水体衰减作用的限制,通常使用衰减系数较小的蓝绿光作为水下成像系统的照明光源。以一种已知粒径分布的水体为算例计算了水体对于蓝绿光波段不同波长光的吸收和散射系数,分析了水下连续光成像系统的后向散射光噪声对于其成像质量的影响,研究了目标反射光信号和水体后向散射光噪声与光波长之间的关系,提出使用光束扩展系数来间接评价水下连续光成像系统的成像质量。仿真结果表明:不同波长的光在水体中所形成的后向散射光噪声不同,对于已知粒径分布的水体而言,存在着使光束扩展系数为最小值的光波长,可以将其视为水下连续光成像系统照明光源的最优化波长。

Underwater continuous laser imaging system（UCLIS）is widely used in the application of marine exploration.But its working range is restricted because of the attenuation of water body,so we primarily use blue-green light,whose attenuation coefficient is smaller,as the illuminant in UCLIS.By taking a sample of a water body whose particle size distribution has been known to us,the absorption and scattering coefficients under the different wavelengths of the blue-green light are calculated in this paper,and the influence of the backscatter noise of UCLIS on the quality of imaging is analyzed.The connection between the reflected signal of the subject and the backscattering noise as well as the wavelengths is studied.It suggests that the imaging quality of UCLIS should be indirectly evaluated by the beam spread parameter.The result of the simulation shows that the backscattering noise in the water body varies with lights of different wavelengths.In the case of a water body with a known particle size distribution,there is a wavelength minimizing the beam spread parameter,and it can be taken as the optimal wavelength of illuminant in UCLIS.