红外辐射偏振建模与仿真研究

发布时间：2018-09-11 15:24

【摘要】：红外辐射探测只是测量目标物体表面的辐射强度,当有辐射强度相同的干扰物体时,不能够区别目标物体和干扰物；红外辐射偏振探测不仅测量目标物体表面的辐射强度,而且测量不同偏振方向上辐射情况,并且不同的物体表面的偏振特性是不同的,所以红外辐射偏振探测能够区分目标物体和干扰物,已经成为研究热点之一。传统红外辐射偏振研究中采用红外辐射发射率的平行分量和垂直分量的和分之差来表示偏振度,使用菲涅尔公式计算菲涅尔反射率,再根据发射率与反射率的关系最后得到基于菲涅尔反射率的红外辐射偏振模型。由于传统模型中菲涅尔反射率是在物体表面镜面反射的前提条件下推导的,只适用于理想光滑物体表面；为了表示不同粗糙度条件下物体表面的红外辐射偏振特性,传统模型实际测量不同粗糙度时物体表面的复折射率,再代入到模型中进行计算,此方法由于忽略了粗糙物体表面的微观分布,使得最终的结果也并不完全准确。针对传统红外辐射偏振模型中忽略粗糙物体表面微观分布这一情况,本文展开了对红外辐射偏振特性的理论研究并建模仿真,基于微面元偏振双向反射分布函数,结合微观结构分布情况建立红外辐射偏振度模型。首先对双向反射分布函数进行研究,引入微面元双向反射分布函数对传统红外辐射偏振模型进行改进,根据基尔霍夫定律和微面元双向反射分布函数得到发射率与半球空间反射率之间的关系。然后研究如何将微面元双向反射分布函数偏振化,计算定向半球空间反射率,继而得到定向发射率矩阵来计算红外辐射偏振度,建立基于偏振双向反射分布函数的红外辐射偏振模型,对其进行仿真实验并分析。实验结果表明,模型仿真得到的红外辐射偏振度与实际测量结果值基本保持一致,并且与传统红外辐射偏振模型仿真结果相比较更符合实测值,在表面粗糙度较大的情况下,能够更准确地反映物体的红外辐射偏振特性。最后本文对典型材质目标物体进行建模并仿真计算红外辐射偏振度图像,进一步验证了本文模型的正确性,并且说明了红外辐射偏振图像能够更好的区分出目标物体并且能够得到细节纹理信息更丰富的图像。
[Abstract]:Infrared radiation detection is only used to measure the radiation intensity of the surface of the target object. When there is an interference object with the same radiation intensity, it is not possible to distinguish the target object from the interference object. The infrared radiation polarization detection not only measures the radiation intensity of the target object surface, And the measurement of radiation in different polarization directions, and the polarization characteristics of different object surface is different, so infrared radiation polarization detection can distinguish between target object and interference object, has become one of the research hotspots. In the traditional research of infrared radiation polarization, the difference between the parallel and vertical components of the infrared emissivity is used to express the polarization degree, and the Fresnel formula is used to calculate the Fresnel reflectivity. Finally, the infrared radiation polarization model based on Fresnel reflectivity is obtained according to the relationship between emissivity and reflectivity. Because the Fresnel reflectivity in the traditional model is derived under the precondition of specular reflection on the surface of the object, it is only applicable to the ideal smooth surface, and in order to express the polarization characteristics of infrared radiation on the surface of the object under different roughness conditions, The traditional model is used to measure the complex refractive index of the surface of the object with different roughness, and then the method is added to the model to calculate it. Because the microscopic distribution of the rough surface is neglected, the final results are not completely accurate. Aiming at neglecting the microscopic distribution of rough object surface in traditional infrared radiation polarization model, the theoretical research and simulation of infrared radiation polarization characteristics are carried out in this paper, based on the polarization bidirectional reflectance distribution function of micro-surface element. The polarization model of infrared radiation is established based on the microstructure distribution. Firstly, the bidirectional reflectance distribution function is studied, and the traditional infrared radiation polarization model is improved by introducing the microplane bidirectional reflectance distribution function. According to Kirchhoff's law and the bidirectional reflectance distribution function of microplane, the relationship between emissivity and the spatial reflectivity of the hemisphere is obtained. Then we study how to polarization the bidirectional reflectance distribution function of the microplane and calculate the spatial reflectance of the oriented hemisphere, and then obtain the directional emissivity matrix to calculate the polarization degree of infrared radiation. A polarization model of infrared radiation based on polarization bidirectional reflectance distribution function is established and simulated and analyzed. The experimental results show that the polarization degree of infrared radiation obtained by the model simulation is basically consistent with the measured results, and is more consistent with the measured results compared with the simulation results of the traditional infrared radiation polarization model. The polarization characteristics of infrared radiation can be reflected more accurately. Finally, the model of typical material object is modeled and the infrared radiation polarization image is simulated, which further verifies the correctness of the model. It also shows that the infrared radiation polarization image can better distinguish the target object and obtain the image with more detailed texture information.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O436.3;TN215

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