Pixel Super-Resolution Phase Retrieval for Lensless On-Chip Microscopy via Accelerated Wirtinger Flow

Area of Science:

• Biomedical Imaging
• Computational Microscopy
• Optics and Photonics

Background:

• Lensless on-chip microscopy, utilizing pixel super-resolution (PSR) and phase retrieval, offers high-throughput biomedical imaging potential.
• Existing PSR phase retrieval methods suffer from lengthy measurement and reconstruction times, limiting their practical application.
• The need for faster, more efficient computational frameworks is critical for advancing on-chip microscopy techniques.

Purpose of the Study:

• To introduce a novel computational framework for accelerated pixel super-resolution (PSR) phase retrieval in lensless microscopy.
• To address the time-consuming nature of current PSR phase retrieval methods.
• To enhance the speed and reduce measurement requirements for on-chip imaging applications.

Main Methods:

• Development of a novel computational framework incorporating a sparsity-promoting regularizer for improved well-posedness with limited measurements.
• Integration of Nesterov's momentum to accelerate iterative reconstruction processes.
• Theoretical analysis for general step size selection to simplify implementation and parameter tuning.

Main Results:

• The proposed accelerated Wirtinger flow (AWF) algorithm demonstrates at least an order of magnitude faster convergence rate compared to existing methods.
• AWF enables a twofold reduction in the required number of measurements while preserving high reconstruction quality.
• The algorithm facilitates simpler implementation without complex parameter tuning, supported by theoretical guidance on step size selection.

Conclusions:

• The accelerated Wirtinger flow (AWF) algorithm significantly enhances the speed and efficiency of lensless on-chip microscopy.
• AWF is compatible with existing lensless microscopy systems, paving the way for label-free, rapid whole slide imaging.
• This advancement enables subpixel resolution imaging of dynamic biological activities, accelerating biomedical research and diagnostics.