# High-Resolution Limited-Angle Phase Tomography of Dense Layered Objects Using Deep Neural Networks

## TL;DR

This paper introduces a deep learning-based method for 3D phase tomography of dense layered objects using limited-angle projections, enabling direct reconstruction from intensity data with minimal physical training data.

## Contribution

A novel physics-informed deep neural network approach that performs direct 3D reconstruction from intensity projections in limited-angle phase tomography.

## Key findings

- Successful experimental demonstration on optical integrated circuit phantom
- Effective reconstruction with synthetic training data alone
- Applicable to various electromagnetic radiation-based tomography

## Abstract

We present a Machine Learning-based method for tomographic reconstruction of dense layered objects, with range of projection angles limited to $\pm $10$^\circ$. Whereas previous approaches to phase tomography generally require two steps, first to retrieve phase projections from intensity projections and then perform tomographic reconstruction on the retrieved phase projections, in our work a physics-informed pre-processor followed by a Deep Neural Network (DNN) conduct the three-dimensional reconstruction directly from the intensity projections. We demonstrate this single-step method experimentally in the visible optical domain on a scaled up integrated circuit phantom. We show that even under conditions of highly attenuated photon fluxes a DNN trained only on synthetic data can be used to successfully reconstruct physical samples disjoint from the synthetic training set. Thus, the need of producing a large number of physical examples for training is ameliorated. The method is generally applicable to tomography with electromagnetic or other types of radiation at all bands.