考虑移相参数匹配的任意腔长下多表面干涉测量

传统的多表面波长调谐移相干涉法只能实现透明被测件处于固定位置下的测量,当移相值或者腔长改变时算法的有效性和求解精度没有被深入讨论和分析。为了在任意腔长下实现透明被测件各表面的同时测量,本文提出了一种可实现自适应移相匹配的加权多步采样算法。首先,基于特征多项式,介绍了一种具有移相误差和耦合误差抑制能力的加权多步相位解调技术,可以同时对被测件的3个表面进行测量;进而,基于Zernike多项式,对移相参考系数和腔长系数的任意组合下的算法求解误差进行了迭代计算和分析,为最优参数的匹配提供参考。仿真结果表明所提出的算法求解残余误差小于3×10^(-4)λ_(0)。此外,引入ISO-25178系列三维高度参数对算法性能进行了验证。在实验中,利用Fizeau干涉仪分别对厚度为10和5 mm的透明平板在不同腔长下进行了测量。仿真和实验的结果表明,所提出的算法可以实现任意腔长和厚度下的多表面测量,其可靠性和实用性得到了验证。

Inverse Radiation Problem in One-DimensionalSemitransparent Plane-Parallel Media

The discrete ordinates method is used to develop a solution to an inverse radiation problem of source term in one-dimensional semitransparent plane-parallel media with opaque and specularly reflecting boundaries. It is assumed that, with the exception of the inhomogeneous source term, all aspects of the radiation transport problem are known. A method is developed to determine the inhomogeneous source term from specified incident radiation intensities on the boundaries. The inverse problem is solved using conjugate gradient method that minimizes the error between the incident radiation intensities calculated and the experimental data. The effects of singl-scattering albedo, scattering asymmetry parameter, wall emissivity, the diffuse fraction of reflectivity, and the optical thickness on the accuracy of the inverse are investigated. The results show that the source term can be estimated accurately, even with noisy data.