Angle measurement method of electronic speckle interferometry based on a Michelson interferometer

We propose a small angle measurement setup that utilizes the electronic speckle pattern interferometry (ESPI). By leveraging different principles within the same device, this method achieves complementary advantages across various angle ranges, enhancing measurement accuracy while maintaining high robustness. By utilizing CCD to record light field information in real-time and combining geometric and ESPI methods, relationships between small angles and light field information are established, allowing for the design of relevant algorithms for real-time angle measurement. Numerical simulations and experiments were conducted to validate the feasibility and practicality of this method. Experimental data show that the geometric method achieves a measurement accuracy of 4.39" and a resolution of 1.828" within a measurement range of 54" . In contrast, the ESPI method demonstrates a higher accuracy of 0.43" and a finer resolution of 0.284", with a theoretical measurement range of up to 0.6^∘. In an angle measurement experiment with a maximum angle of approximately 0.1^∘, the combined application of both methods achieved a measurement accuracy of 7.68" and a resolution of 3.75". This approach effectively compensates for the limitations in measuring small angles over a large angular range, demonstrating significant potential for applications in precision measurement, optical testing, and related fields.