Improving Acquisition Speed of X-Ray Ptychography through Spatial Undersampling and Regularization

TL;DR

This paper enhances X-ray ptychography by introducing regularization techniques that enable accurate imaging at lower overlap ratios, thus improving acquisition speed and robustness.

Contribution

The study demonstrates that regularizing phase retrieval with image priors allows effective reconstruction with reduced data overlap, advancing ptychography efficiency.

Findings

Object reconstruction is feasible at low overlap ratios with regularization.

Total-Variation and Structure Tensor Priors improve phase retrieval robustness.

Effective on real IC chip data, confirming practical applicability.

Abstract

X-ray ptychography is one of the versatile techniques for nanometer resolution imaging. The magnitude of the diffraction patterns is recorded on a detector and the phase of the diffraction patterns is estimated using phase retrieval techniques. Most phase retrieval algorithms make the solution well-posed by relying on the constraints imposed by the overlapping region between neighboring diffraction pattern samples. As the overlap between neighboring diffraction patterns reduces, the problem becomes ill-posed and the object cannot be recovered. To avoid the ill-posedness, we investigate the effect of regularizing the phase retrieval algorithm with image priors for various overlap ratios between the neighboring diffraction patterns. We show that the object can be faithfully reconstructed at low overlap ratios by regularizing the phase retrieval algorithm with image priors such as Total-Variation and Structure Tensor Prior. We also show the effectiveness of our proposed algorithm on real data acquired from an IC chip with a coherent X-ray beam.