基于LCTF成像仪的光谱反射率测量研究

Research on spectral reflectance measurement based on LCTF imager

目标物体的光谱反射率是水下光谱检测中重要的物理特性。复杂的水下环境,尤其是浑浊水体对光有较强的吸收与散射作用,增大了光谱探测的难度。文中在比对测量法的基础上,提出了引入黑、白板对测量结果进行矫正的光谱反射率探测方法。利用基于液晶可调谐滤光片的水下光谱成像仪快速稳定地采集多浊度、多光照条件下的光谱图像数据。数据分析结果证明了浊度增加会使得黑、白板的像素响应比值非线性增加,尤其在400~500 nm范围内。且基于黑白板的光谱反射率探测方法可以有效去除水体散射对光谱反射率重建的影响,使得不同浊度条件下得到的目标物光谱反射率最大绝对误差为5.3%。

Spectral reflectance of targeted object is considered a vital inherent physical property in underwater spectral detection.However,the underwater environment poses significant challenges in spectral detection through strong absorption and scattering effects of light.To explore the influence of water turbidity on the accuracy of spectral detection,this paper describes the spectral reflectance detection under varying turbidity.Underwater spectral imaging system based on liquid crystal tunable filter(LCTF)is used for experimentation.Results proved that the increase in turbidity will further enhance the scattering intensity of water body.Based on the nonlinear increase in the pixel response of black and white board,the rapid upsurge in scattering intensity between 400–500 nm is noticed.Simultaneously,the spectral reconstruction method is applied,which yielded in maximum absolute error of 5.3%for spectral reflectance under different turbidity conditions.