Reconstruction of a piecewise smooth absorption coefficient by an acousto-optic process

TL;DR

This paper develops a mathematical framework for reconstructing piecewise smooth optical absorption coefficients using acousto-optic measurements, introducing new equations and iterative methods with proven convergence.

Contribution

It generalizes previous acousto-optic reconstruction methods to handle piecewise smooth absorption distributions with a new distributional equation and iterative convergence proof.

Findings

Established a new distributional equation for absorption coefficient

Developed a Landweber type iterative reconstruction method

Proved convergence of the reconstruction sequence

Abstract

The aim of this paper is to tackle the nonlinear optical reconstruction problem. Given a set of acousto-optic measurements, we develop a mathematical framework for the reconstruction problem in the case where the optical absorption distribution is supposed to be a perturbation of a piecewise constant function. Analyzing the acousto-optic measurements, we establish a new equation in the sense of distributions for the optical absorption coefficient. For doing so, we introduce a weak Helmholtz decomposition and interpret in a weak sense the cross-correlation measurements using the spherical Radon transform. We next show how to find an initial guess for the unknown coefficient and finally construct the true coefficient by providing a Landweber type iteration and proving that the resulting sequence converges to the solution of the system constituted by the optical diffusion equation and the new equation mentioned above. Our results in this paper generalize the acousto-optic process proposed in [Ammari, Garnier, Nguyen and Seppecher, 2012] for piecewise smooth optical absorption distributions.