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

Area of Science:

• Optical Engineering
• Metrology
• Interferometry

Background:

• Accurate measurement of small angles is critical in precision engineering and optical testing.
• Existing methods often face limitations in accuracy, resolution, or measurement range for small angles.

Purpose of the Study:

• To develop and validate a hybrid measurement system for precise small angle determination.
• To leverage complementary strengths of geometric and ESPI techniques within a single setup.

Main Methods:

• A setup integrating geometric optics and electronic speckle pattern interferometry (ESPI) was designed.
• Charge-coupled device (CCD) cameras were used for real-time light field data acquisition.
• Algorithms were developed to correlate light field information with angle measurements.

Main Results:

• The geometric method achieved 4.39" accuracy and 1.828" resolution over a 54" range.
• The ESPI method provided 0.43" accuracy and 0.284" resolution up to 0.6°.
• The combined system demonstrated 7.68" accuracy and 3.75" resolution for angles up to 0.1°.

Conclusions:

• The hybrid approach effectively overcomes limitations of individual methods for small angle measurements.
• This technique offers enhanced accuracy and robustness for precision measurement and optical testing applications.