Recovering scattering obstacles by multi-frequency phaseless far-field data

TL;DR

This paper introduces a method to recover both the shape and location of scattering obstacles using multi-frequency phaseless far-field data by breaking translation invariance with superposed incident waves.

Contribution

It demonstrates that superpositions of two plane waves can break translation invariance, enabling simultaneous shape and position recovery from phaseless data.

Findings

Successful recovery of obstacle shape and location in numerical tests

The proposed algorithm effectively utilizes multi-frequency data

Breaking translation invariance improves inverse scattering results

Abstract

It is well known that the modulus of the far-field pattern (or phaseless far-field pattern) is invariant under translations of the scattering obstacle if only one plane wave is used as the incident field, so the shape but not the location of the obstacle can be recovered from the phaseless far-field data. In this paper, it is proved that the translation invariance property of the phaseless far-field pattern can be broken if superpositions of two plane waves are used as the incident fields for all wave numbers in a finite interval. Based on this, a recursive Newton-type iteration algorithm in frequencies is then developed to recover both the location and the shape of the obstacle simultaneously from multi-frequency phaseless far-field data. Numerical examples are also carried out to illustrate the validity of the approach and the effectiveness of the inversion algorithm.