摘要
波长与表面起伏高度的相对数值会直接影响目标表面粗糙度的判定,因而波长是影响双向反射分布函数模型精度的重要参数之一。聚焦波长影响,基于光谱双向反射分布函数六参数模型,建立几何衰减因子与波长的函数关系。结合实验测量,反演各入射波长下模型中六参数,并凝练波长对六参数的影响规律;分析模型误差,拟合推导出几何衰减因子与波长之间的函数关系。结果表明:在几何衰减因子中增加一个与波长呈指数相关的系数,可以明显提高大散射角时光谱双向反射分布函数六参数模型的精度,并减小受波长影响产生的模型误差,目标样片的均方根误差较优化前减小约40%;波长主要影响六参数中的b、k_(b)、k_(d)、k_(r),其数值变化范围和趋势转折点波段位置与样片材质和表面粗糙度相关。研究结果可为鉴别伪装和反伪装目标,以及目标的态势感知提供理论支撑和技术支持。
In studies related to the scattering characteristics of objectives of physical context,the Bidirectional Reflection Distribution Function(BRDF)is the preferred option for describing the anisotropy of objectives.The geometric attenuation factor in BRDF model has a great impact on the accuracy of BRDF model,which is related to the target surface undulation,roughness and refractive index of the material.The current research and optimization of geometric attenuation factor is mostly from the perspective of surface geometric structure,such as target surface masking and shadowing.The wavelength is not included in influencing factors.However,the relative value of wavelength and surface undulation height directly affects the determination of target surface roughness,thus interfering the geometric attenuation factor,which seriously affects the accuracy of BRDF model.It is necessary to take the wavelength as a part of geometric attenuation factor,study their functional relationship and condense their law of influence.This paper establishes an empirical functional model of the geometric attenuation factor by optimizing the existing geometric attenuation factor from experimental data.Based on the six-parameter spectral BRDF model,the measurement data of target plants is used to inverse the six-parameter values at different incident wavelengths,and the influence law of wavelength on the six-parameter is condensed.The numerical relationships among error values,wavelength,and geometric attenuation factor are analyzed to calculate the expression for the geometric attenuation factor as a function of wavelength.The feasibility of the optimization idea in this paper is verified by comparing the Root Mean Square Errors(RMSE)before and after adding the coefficients related to wavelength.The results show that adding a coefficient,which is exponentially correlated to wavelength,to geometric attenuation factor can significantly improve the accuracy of the six-parameter spectral BRDF model at large scattering angles and reduce the modeling error due to the influence of wavelength.The optimized geometric attenuation factor better fits the measured value versus wavelength curve,and the RMSE of target plants is reduced by about 40%compared to pre-optimization.The wavelength has a weak effect on the a,c parameters,while the effect on the b,k_(b),k_(d),k_(r)parameters is more pronounced.Wavelength mainly affects the range of numerical changes and the band location of trend turning point.The specific pattern is affected by the material and surface roughness of target plants after preliminary analysis.
作者
余越
王利国
王彪
阳志强
张格
靳皓然
吴振森
赵保银
巩蕾
YU Yue;WANG Liguo;WANG Biao;YANG Zhiqiang;ZHANG Ge;JIN Haoran;WU Zhensen;ZHAO Baoyin;GONG Lei(School of Photoelectric Engineering,Xi'an Technological University,Xi'an 710021,China;National Key Laboratory of Scattering and Radiation,Shanghai 200438,China;School of Physics,Xidian University,Xi'an 710071,China;Xi'an Oe Photonics Co.,Ltd.,Xi'an 710021,China)
出处
《光子学报》
北大核心
2025年第1期93-103,共11页
Acta Photonica Sinica
基金
国家自然科学基金(No.62201566)
陕西省教育厅2023年度重点科学研究计划(No.23JY035)
陕西省自然科学基金(No.2024JC-YBMS-523)
陕西高校青年创新团队(No.K20220184)
陕西省“两链”融合光子集成与光子制造重点专项(No.2021LLRH-03)。
关键词
光谱双向反射分布函数
几何衰减因子
多波长
六参数模型
遮蔽效应
Spectral bidirectional reflectance distribution function
Geometric attenuation factor
Multiple wavelengths
Six-parameter model
Masking effect
作者简介
第一作者:余越,15195852020@163.com;通讯作者:巩蕾,gonglei@xatu.edu.cn。
