Optimal illumination pattern for transport-of-intensity quantitative phase microscopy

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Computational Imaging

Background:

• The transport-of-intensity equation (TIE) is a key non-interferometric method for quantitative phase imaging (QPI) of transparent samples.
• TIE is limited by low-frequency artifacts and phase blurring under low-coherence illumination.
• Previous aperture designs were empirical, not optimized for TIE performance.

Purpose of the Study:

• To optimize illumination patterns for enhanced TIE-based QPI.
• To address limitations of low-frequency errors and phase blurring in TIE.
• To develop a systematic approach for designing optimal illumination apertures.

Main Methods:

• Optimization of illumination patterns using a quantitative criterion for aperture "goodness".
• Focus on binary-coded axis-symmetric illumination patterns for isotropic TIE phase transfer functions.
• Implementation using a small-pitch LED array for testing.

Main Results:

• The optimized illumination pattern significantly improved signal-to-noise ratio (SNR) and spatial resolution.
• Demonstrated superior performance compared to suboptimal illumination patterns.
• Successfully imaged a phase resolution target and HeLa cells with enhanced quality.

Conclusions:

• Optimized illumination patterns are crucial for maximizing TIE performance.
• The developed method offers a significant advancement for TIE-based QPI.
• This approach provides a pathway for improved phase retrieval in various applications.