Stress measurement method and error correction based on polarization camera

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.