Extended Depth-of-Field Lensless Imaging using an Optimized Radial Mask

TL;DR

This paper introduces an optimized radial amplitude coded mask for lensless cameras, significantly extending the depth of field by improving frequency response and validating performance through simulations and real-world experiments.

Contribution

It presents a shape-preserving optimization scheme for radial masks, enhancing depth-of-field extension in lensless imaging systems.

Findings

Optimized radial mask shows improved frequency response.

Extended depth of field demonstrated in simulations.

Prototype validation confirms real-world effectiveness.

Abstract

The freedom of design of coded masks used by mask-based lensless cameras is an advantage these systems have when compared to lens-based ones. We leverage this freedom of design to propose a shape-preserving optimization scheme for a radial-type amplitude coded mask. Due to the depth-independency of the radial mask's point spread function, they can be used for extending the effective depth of field (DOF) of a lensless imaging system. In this paper we optimized a coded mask for improved frequency response, while retaining its radial characteristics and therefore extended-DOF capabilities. We show that our optimized radial mask achieved better overall frequency response when compared to naive implementations of a radial mask. We also quantitatively and qualitatively demonstrated the extended DOF imaging achieved by our optimized radial mask in simulations by comparing it to different non-radial coded masks. Finally, we built a prototype camera to validate the extended DOF capabilities of our coded mask in real scenarios.