基于穆勒矩陣的目標光學反射特性研究
發(fā)布時間：2018-07-28 17:15
【摘要】：目標光學反射的偏振特性研究在民用和軍事上顯示出了極大的應用價值和發(fā)展?jié)摿�。傳統(tǒng)偏振特性研究,根據目標自身穆勒矩陣的表達形式,將其分解為起偏、退偏和衰減等模塊,是一種目標特性的數學表征,缺乏物理意義,具有一定的局限性;而本文將麥克斯韋方程與穆勒矩陣相結合,推導出利用穆勒矩陣計算目標折射率,消光系數,退偏振系數等的方法,這些系數具備明確的物理意義,可以作為新的偏振特征,從而為目標光學反射特性研究提供更有價值的信息。本文首先對最基礎的麥克斯韋方程組微分形式進行求解,得到關于電磁場強度矢量的波動方程,根據目標表面有無電導率,結合折射率定義,得出了光學常數的存在。其次根據菲涅爾反射公式中,p波s波的反射系數,定義了兩者的振幅比以及相位差。然后根據測量所得穆勒矩陣,將其轉換為穆勒瓊斯矩陣,穆勒瓊斯矩陣是一個可以由菲涅爾反射系數表示的矩陣,對其進行求解,即可得到振幅比以及相位差。最后再結合菲涅爾反射公式以及折射定律,得出光學常數關于入射角的表達式。其次,本文推導出一種路徑積分矩陣,它與穆勒矩陣存在轉換關系。將路徑積分矩陣分解,得到參量退偏振系數,它可以用來反映被測量目標對偏振特性的改變程度。由于路徑積分矩陣是每束光傳播路徑的瓊斯矩陣的概率混合,這一特性使得路徑積分矩陣成為混合材料以及粗糙表面物理建模的好方法。并且由于多次散射容易造成退偏振,造成多次散射的原因是物體表面曲率較大甚至不光滑時,因此退偏振系數與物體表面粗糙度存在一定的關系,可以用于粗糙表面的實驗仿真,并將其作為一個重要參數對目標進行分辨。為了獲得目標自身穆勒矩陣,本文設計出一種多旋轉式測量裝置,通過偏振片和波片的不同組合來獲得不同偏振態(tài)的出射光。由于穆勒矩陣包含16個元素,為了能夠精確得到穆勒矩陣中的每一個參數信息,首先構建一個多角度的測量系統(tǒng),使用七種不同的入射角(30°,37.5°,45°,52.5°,60°,67.5°,75°)對目標反射光進行測量,即入射光和反射光與法線的夾角可以變化�？刂破鹌到y(tǒng)得到6組不同的入射光斯托克斯矢量照射到目標表面,同時針對每組入射光控制檢偏系統(tǒng)測量6組反射光斯托克斯矢量。為了能夠精確地控制經過起偏系統(tǒng)后出射光的偏振態(tài),在擴束透鏡組與起偏系統(tǒng)之間加入了一組圓偏振態(tài)發(fā)生器,使通過起偏系統(tǒng)后產生的多組入射光光強值保持一致。最后,根據測量得到的目標穆勒矩陣,計算出反映目標光學特性的偏振參量,對路徑積分矩陣進行分解得到的退偏振系數也用于偏振特性分析。利用所設計的系統(tǒng)對自然界中典型的目標以及復雜自然背景下的人造目標和偽裝目標進行大量實驗測量。結果表明,本文推導的偏振指標可以對不同種類的目標進行區(qū)分,并且可以對目標所表現出的偏振特性差異進行分析,論證了通過理論推導所得的目標光學常數以及退偏振系數對于區(qū)分目標的可行性與實用性。
[Abstract]:The study of the polarization characteristics of the target optical reflection has shown great application and development potential in civil and military. The study of the traditional polarization characteristics, based on the expression of the Muller matrix of the target itself, decomposes it into a module of bias, depolarization and attenuation. It is a mathematical representation of the specificity of the target, lacking physical meaning and has a certain degree. In this paper, the Maxwell equation and the Muller matrix are combined to derive the method of using the Muller matrix to calculate the target refractive index, the extinction coefficient, the depolarization coefficient and so on. These coefficients have clear physical meaning and can be used as new polarization characteristics, thus providing more valuable information for the study of the target optical reflection characteristics. First, the differential equation of the most basic Maxwell equation group is solved, and the wave equation about the intensity vector of the electromagnetic field is obtained. According to the conductivity of the target surface and the definition of the refractive index, the existence of the optical constant is obtained. Secondly, the amplitude ratio of the P wave S wave is defined according to the reflection coefficient of the Finel reflection formula, and the amplitude ratio of the two is defined. The phase difference is then converted to a Muller Jones matrix according to the Muller matrix measured. The Muller Jones matrix is a matrix which can be expressed by the Finel reflection coefficient. The amplitude ratio and the phase difference can be obtained by solving it. Finally, the equation of Finel reflection and the law of refraction are combined to obtain the angle of the optical constant about the incident angle. Secondly, this paper derives a path integral matrix, which has the transformation relationship with the Muller matrix. The path integral matrix is decomposed and the parameter depolarization coefficient is obtained. It can be used to reflect the degree of change of the polarization characteristic of the measured target. Because the path integral matrix is the probability mixing of the Jones matrix of each beam propagation path, This characteristic makes the path integral matrix a good method for the physical modeling of the mixed material and the rough surface. And because the multiple scattering is easy to cause depolarization, the cause of multiple scattering is that the surface curvature of the object is larger or not smooth, so the depolarization coefficient has a certain relation with the surface roughness of the object, and it can be used in the rough surface. In order to obtain the Muller matrix of the target itself, a multi rotation measuring device is designed to obtain different polarization states of the emitted light by different combinations of polarizers and wave plates. The Muller matrix contains 16 elements, in order to be accurately obtained. Each parameter information in the Muller matrix is first constructed with a multi angle measurement system, using seven different incident angles (30, 37.5, 45, 52.5, 60, 67.5, 75) to measure the reflected light of the target, that is, the angle between the incident light and the reflected light and the normal line can be changed. The control deviation system gets 6 different incident light of the incident light. The vector is irradiated to the target surface, and 6 groups of reflected light Stokes vectors are measured for each group of incident light control detection. In order to accurately control the polarization state of the ejection light after the polarizing system, a set of circular polarization generator is added between the beam enlargement system and the offset system to make the multiple groups of input generated by the polarizing system. The intensity of light intensity is consistent. Finally, according to the measured target Muller matrix, the polarization parameters that reflect the optical properties of the target are calculated. The depolarization coefficient of the decomposition of the path integral matrix is also used for the analysis of polarization properties. The target and the camouflage target are measured in a large number of experiments. The results show that the polarization indexes derived in this paper can be distinguished from different kinds of targets, and the polarization characteristics of the target can be analyzed. The feasibility of the target optical constant and the depolarization coefficient to distinguish the target can be demonstrated by the theoretical deduction. Sex and practicality.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O436.3
[Abstract]:The study of the polarization characteristics of the target optical reflection has shown great application and development potential in civil and military. The study of the traditional polarization characteristics, based on the expression of the Muller matrix of the target itself, decomposes it into a module of bias, depolarization and attenuation. It is a mathematical representation of the specificity of the target, lacking physical meaning and has a certain degree. In this paper, the Maxwell equation and the Muller matrix are combined to derive the method of using the Muller matrix to calculate the target refractive index, the extinction coefficient, the depolarization coefficient and so on. These coefficients have clear physical meaning and can be used as new polarization characteristics, thus providing more valuable information for the study of the target optical reflection characteristics. First, the differential equation of the most basic Maxwell equation group is solved, and the wave equation about the intensity vector of the electromagnetic field is obtained. According to the conductivity of the target surface and the definition of the refractive index, the existence of the optical constant is obtained. Secondly, the amplitude ratio of the P wave S wave is defined according to the reflection coefficient of the Finel reflection formula, and the amplitude ratio of the two is defined. The phase difference is then converted to a Muller Jones matrix according to the Muller matrix measured. The Muller Jones matrix is a matrix which can be expressed by the Finel reflection coefficient. The amplitude ratio and the phase difference can be obtained by solving it. Finally, the equation of Finel reflection and the law of refraction are combined to obtain the angle of the optical constant about the incident angle. Secondly, this paper derives a path integral matrix, which has the transformation relationship with the Muller matrix. The path integral matrix is decomposed and the parameter depolarization coefficient is obtained. It can be used to reflect the degree of change of the polarization characteristic of the measured target. Because the path integral matrix is the probability mixing of the Jones matrix of each beam propagation path, This characteristic makes the path integral matrix a good method for the physical modeling of the mixed material and the rough surface. And because the multiple scattering is easy to cause depolarization, the cause of multiple scattering is that the surface curvature of the object is larger or not smooth, so the depolarization coefficient has a certain relation with the surface roughness of the object, and it can be used in the rough surface. In order to obtain the Muller matrix of the target itself, a multi rotation measuring device is designed to obtain different polarization states of the emitted light by different combinations of polarizers and wave plates. The Muller matrix contains 16 elements, in order to be accurately obtained. Each parameter information in the Muller matrix is first constructed with a multi angle measurement system, using seven different incident angles (30, 37.5, 45, 52.5, 60, 67.5, 75) to measure the reflected light of the target, that is, the angle between the incident light and the reflected light and the normal line can be changed. The control deviation system gets 6 different incident light of the incident light. The vector is irradiated to the target surface, and 6 groups of reflected light Stokes vectors are measured for each group of incident light control detection. In order to accurately control the polarization state of the ejection light after the polarizing system, a set of circular polarization generator is added between the beam enlargement system and the offset system to make the multiple groups of input generated by the polarizing system. The intensity of light intensity is consistent. Finally, according to the measured target Muller matrix, the polarization parameters that reflect the optical properties of the target are calculated. The depolarization coefficient of the decomposition of the path integral matrix is also used for the analysis of polarization properties. The target and the camouflage target are measured in a large number of experiments. The results show that the polarization indexes derived in this paper can be distinguished from different kinds of targets, and the polarization characteristics of the target can be analyzed. The feasibility of the target optical constant and the depolarization coefficient to distinguish the target can be demonstrated by the theoretical deduction. Sex and practicality.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O436.3
【參考文獻】
相關期刊論文 前10條
1 楊蔚;顧國華;陳錢;周驍俊;徐富元;;穆勒矩陣圖像的獲取及處理[J];紅外與激光工程;2015年12期
2 唐s顂，
本文編號：2151009
本文鏈接：http://www.sikaile.net/shoufeilunwen/benkebiyelunwen/2151009.html
