Robustness to misalignment of low-cost, compact quantitative phase imaging architectures.

Area of Science:

• Optical imaging
• Biomedical engineering

Background:

• Quantitative phase imaging (QPI) offers label-free contrast but often requires complex interferometric setups.
• Miniaturization of QPI systems is essential for applications like capsule endoscopy.

Purpose of the Study:

• To investigate non-interferometric QPI architectures for low-cost, miniaturized devices.
• To analyze and mitigate the impact of sensor misalignment on QPI performance in capsule endoscopy.

Main Methods:

• Simulations and experimental validation of a folded 4f correlator architecture.
• Development of techniques for axial misalignment compensation in the 4f correlator.
• Analysis of axial/transverse misalignment and manufacturing variations on a phase plate architecture.

Main Results:

• A novel technique for identifying and compensating axial misalignment in the 4f correlator was demonstrated.
• A trade-off between phase plate resolution and algorithm convergence time was identified under misalignment.
• The phase plate architecture exhibited greater robustness to sensor misalignment compared to the 4f correlator.

Conclusions:

• Both investigated architectures are viable for developing compact QPI systems.
• The phase plate architecture shows higher resilience to misalignment, making it promising for capsule endoscopy.
• Further development is warranted to realize low-cost, miniaturized QPI for capsule endoscopy.