透明物体面形偏振成像测量技术综述

Review of Shape from Polarization for Transparent Object

无偏漫射光被物体反射后变为部分偏振光,菲涅尔定律阐明了入射角和反射光偏振度的定量关系。入射面的方位角和反射光的偏振角存在90°的方位差,由此可以获得入射面的方位角。综述了透明物体面形偏振成像测量的研究进展,首先介绍了Lawrence B Wolff提出的反射模型及透明物体反射光类型;进一步介绍了基于镜面反射光偏振特性的透明物体面形偏振成像测量原理,并针对测量中存在的入射角和入射面方位角歧义问题,综述了目前国内外消除入射角和消除入射面方位角歧义的方法。鉴于已有算法均假定反射光线平行于偏振成像系统的光轴,但实际应用中常常不能满足这个假设,为此简单介绍了作者提出的基于向量运算的透明物体面形偏振成像测量方法;最后分析了透明物体面形偏振成像测量进一步的研究方向。

A nonpolarized iight, after being reflected by an object, becomes partially linearly polarized. Given the refractive index, Fresnel＇s law gives the quantitative relation between degree of polarization and incident angle. The polarization angle of secularly reflected light is 90 degree from the azimuth angle of the incident plane. In this paper, we review the theory basis and algorithm of shape from polarization for transparent object. Firstly, the reflection model proposed by Lawrence B Wolff is introduced, which illustrates the reflection feature of transparent object. Then is the algorithm of shape from polarization for transparent object based on polarization of specularly reflected light. Since the azimuth angle ambiguity and zenith angle ambiguity are inherent to shape from polarization algorithm, techniques for disambiguity are reviewed respectively. Existing algorithm of shape from polarization were allestablished on the assumption that the reflected light is parallel to the optical axis of the polarimetry, which is not always satisfied in actual application. To devote this problem, the vector based algorithm by the author is briefly introduced. Finally, the future research direction is pointed out.