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Presenter: Khaled Kelany
Supervisor:

Date: Tue, August 10, 2021
Time: 10:00:00 - 00:00:00
Place: ZOOM - Please see below.

ABSTRACT

Link: https://uvic.zoom.us/j/87071393897?pwd=K1EzeStmeWhFK0crK0RScVhweGlyZz09

Meeting ID: 870 7139 3897

Password: 693901

Note: Please log in to Zoom via SSO and your UVic Netlink ID

Abstract: The focus of this work is to explore the use of quantum annealing solvers for the problem of phase unwrapping of synthetic aperture radar (SAR) images. Although solutions to this problem exist based on network programming, these techniques do not scale well to larger-sized images.
Our approach involves formulating the problem as a quadratic unconstrained binary optimization (QUBO) problem, which can be solved on a quantum annealer. Given that present embodiments of quantum annealers remain limited in the number of qubits they possess, we decompose the problem into a set of subproblems that can be solved individually. These individual solutions are close to optimal up to an integer constant, with one constant per sub-image. In a second phase, these integer constants are determined as a solution to yet another QUBO problem. We test our approach with various software-based QUBO solvers and on a variety of synthetic and real images. Additionally, we experiment using D-Wave Systems’ quantum annealer, the D-Wave 2000Q. The software-based solvers obtain high-quality solutions comparable to state-of-the-art phase-unwrapping solvers. We are currently working on optimally mapping the problem onto the restricted topology of the quantum annealer to improve the quality of the solution.