Quantitative multi-height phase retrieval via a coded image sensor.

Area of Science:

• Optics and Photonics
• Image Processing
• Biomedical Imaging

Background:

• Multi-height phase retrieval is challenged by the loss of slow-varying phase information, crucial for low-frequency content.
• Traditional methods struggle to recover low-frequency phase profiles, limiting quantitative phase imaging.
• Existing lensless phase retrieval techniques often fail to capture comprehensive phase information.

Purpose of the Study:

• To introduce a coded image sensor for enhanced multi-height phase retrieval.
• To address the loss of low-frequency phase information in phase diversity measurements.
• To enable quantitative phase imaging with improved accuracy and image quality.

Main Methods:

• A coded layer was integrated onto an image sensor to encode slow-varying wavefronts into measurable intensity variations.
• A reconstruction scheme, inspired by blind ptychography, was developed to jointly recover the object and coded layer.
• Multi-height measurements were utilized for both simulations and experimental validation.

Main Results:

• The coded image sensor successfully restored quantitative phase information, including previously lost slow-varying profiles.
• Simulations and experiments confirmed the effectiveness of the proposed reconstruction scheme.
• The coded sensor demonstrated superior image quality compared to regular image sensors.
• The method was validated with various biospecimens, outperforming standard lensless multi-height phase retrieval.

Conclusions:

• The coded image sensor is a viable solution for overcoming limitations in multi-height phase retrieval.
• This approach enables true quantitative phase imaging for lensless, multi-height, and multi-wavelength setups.
• The technology holds promise for advancing applications in microscopy and biomedical imaging.