Novel phase unwrapping approach based on lateral resolution
Alim Yolalmaz, Jeroen Kalkman
TL;DR
This work addresses the persistent challenge of recovering true phase from wrapped phase data plagued by the $2\pi$ ambiguity. It introduces a novel approach that increases sampling frequency by magnifying the phase object with a lateral magnification objective, thereby dispersing phase information across more image-plane samples and reducing sensitivity to $2\pi$ jumps. In a capillary-tube-in-water experiment, unwrapping without magnification yields a moderate accuracy and a substantial thickness error, whereas 4× and 8× magnifications achieve very high correlations with the ground-truth phase (≈0.996 and ≈0.998) and high accuracy (≈91–95%), demonstrating the efficacy of higher sampling density. The method suggests significant potential for improving ground-truth phase recovery in optical holography, MRI, and optical diffraction tomography, offering a practical route to more accurate quantitative imaging.
Abstract
The phase unwrapping plays a key role in obtaining a ground-truth phase of the wrapped phase. High-accurate unwrapped phases are demanded in various research fields such as optical holography, optical diffraction tomography, and magnetic resonance imaging. Unfortunately, the ground-truth phase is not accessible due to 2pi ambiguity which arises from phase jumps in the wrapped phase. In this paper, we propose a novel approach to improve the accuracy of unwrapping process. We increase the sampling frequency by employing a magnifying objective to reconstruct the unwrapped phase with high accuracy for the application of optical holography. Our result shows that optical magnification enables us to improve the accuracy of the true phase by 42%. We deeply believe that our approach will demonstrate significant achievement in obtaining ground-truth phases in various research fields such as optical holography, magnetic resonance imaging, and optical diffraction tomography.