Entrance pupil masks for enhancing moiré-based distance/motion sensing

Area of Science:

• Optics
• Diffraction Physics
• Metrology

Background:

• Higher-order diffraction patterns in moiré imaging are crucial for sensitive range-finding.
• Lower contrast of these higher-order frequencies limits current detection capabilities.

Purpose of the Study:

• To optically enhance moiré pattern contrast using pupil function design.
• To improve the sensitivity of range-finding systems by increasing contrast of higher-order moiré frequencies.

Main Methods:

• Design and simulation of candidate pupil functions for optimized spatial frequency performance.
• Experimental implementation of a selected pupil mask.
• Comparison of moiré image contrast between the designed pupil and a clear aperture.

Main Results:

• A specifically designed pupil mask significantly increases moiré pattern contrast compared to a clear aperture.
• The designed pupil enhances performance beyond diffraction-limited capabilities at targeted spatial frequencies.
• Both simulation and experimental data confirm the increased contrast and sensing capabilities.

Conclusions:

• Pupil function design is an effective strategy for boosting moiré image contrast.
• This approach improves the detection of higher-order diffraction patterns for enhanced range-finding sensitivity.
• The developed entrance pupil mask offers superior sensing capabilities for optical metrology.