一种基于偏振相机的应力测量方法及其误差校正

Stress measurement method and error correction based on polarization camera

  • 摘要: 基于Muller矩阵和 Stokes矢量测量原理,提出了一种利用圆偏振光、无旋转元件的应力测量和在线误差校正方法。该方法通过偏振相机获取的光强信息计算出待测样品的相位延迟,对相位延迟进行溯源便可得到样品的应力分布。通过分析标准1/4波片的相位延迟和偏振相机消光比对测量结果的影响,提出了相应的在线测量与校正方法。为验证方案的可行性,搭建了一套应力测量系统,利用该系统测量了一块经计量部门赋值的633 nm波长的1/4波片,并用提出的误差校正方法校正了测量结果。结果表明:校正前后波片相位延迟相对误差分别为11.5%和1.73%,校正后的相对误差主要由线偏振器产生。所提方法具有测量过程简单、精确度高等特点。

     

    Abstract: Based on the Muller matrix and Stokes vector measurement principles, a stress measurement and online error correction method using circularly polarized light and no rotating elements was proposed. The phase delay of the sample to be tested was calculated by the light intensity information captured by polarization camera, and the stress distribution of the sample could be obtained by tracing the phase delay. By analyzing the effect of the phase delay of standard quarter wave plate and the extinction ratio of polarization camera on the measurement results, the corresponding online measurement and calibration method was proposed. To verify the feasibility of the proposed approach, a stress measurement system was constructed. A quarter wave plate with 633 nm wavelength assigned by the metrological service was measured by this system, and the measurement results were corrected by the proposed error correction method. The results show that the relative errors of the wave plate phase delay before and after correction are 11.5% and 1.73%, respectively, and the corrected relative errors are primarily caused by the linear polarizer. The proposed method exhibits characteristics such as simple measurement process and high accuracy.

     

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