The multidimensional phase unwrapping integral and applications to microwave tomographical image reconstruction

Area of Science:

• Electromagnetics
• Image Reconstruction
• Computational Physics

Background:

• Phase unwrapping is essential for analyzing time-varying electromagnetic fields across various scientific disciplines.
• Applications include synthetic aperture radar (SAR) interferometry, magnetic resonance imaging (MRI), and microwave tomography.
• Existing methods face challenges with phase singularities, particularly in complex scenarios.

Purpose of the Study:

• To present a fundamental framework for spatial phase unwrapping of electromagnetic fields.
• To introduce and develop strategies for dynamic phase unwrapping in microwave image reconstruction.
• To address the challenge of varying phase singularity locations during iterative image reconstruction.

Main Methods:

• Developed a fundamental framework based on the phase unwrapping integral for complex electromagnetic fields.
• Introduced the concept of dynamic phase unwrapping to account for shifting singularity locations.
• Implemented and tested strategies for dynamic phase unwrapping in Gauss-Newton iterative microwave image reconstruction.

Main Results:

• The proposed framework effectively handles phase singularities within closed path integrals.
• Dynamic phase unwrapping strategies were successfully developed and tested.
• Validation was achieved through simulations and clinical experiments with large, high-contrast targets.

Conclusions:

• The dynamic phase unwrapping framework provides a robust solution for complex electromagnetic field analysis.
• This approach is particularly beneficial for iterative microwave image reconstruction where property distributions change.
• The successful validation demonstrates the practical applicability in simulations and clinical settings.