Inverse diffusion from knowledge of power densities

TL;DR

This paper presents a method to uniquely and stably reconstruct a diffusion coefficient inside a domain using multiple internal power density measurements derived from acoustic perturbations, with explicit reconstruction formulas provided.

Contribution

It introduces a novel approach for diffusion coefficient reconstruction from internal power densities obtained via acoustic perturbations, including explicit formulas and stability analysis.

Findings

Unique and stable reconstruction of diffusion coefficient demonstrated.

Explicit formulas for reconstruction provided.

Results applicable in ultrasound modulated imaging techniques.

Abstract

This paper concerns the reconstruction of a diffusion coefficient in an elliptic equation from knowledge of several power densities. The power density is the product of the diffusion coefficient with the square of the modulus of the gradient of the elliptic solution. The derivation of such internal functionals comes from perturbing the medium of interest by acoustic (plane) waves, which results in small changes in the diffusion coefficient. After appropriate asymptotic expansions and (Fourier) transformation, this allow us to construct the power density of the equation point-wise inside the domain. Such a setting finds applications in ultrasound modulated electrical impedance tomography and ultrasound modulated optical tomography. We show that the diffusion coefficient can be uniquely and stably reconstructed from knowledge of a sufficient large number of power densities. Explicit expressions for the reconstruction of the diffusion coefficient are also provided. Such results hold for a large class of boundary conditions for the elliptic equation in the two-dimensional setting. In three dimensions, the results are proved for a more restrictive class of boundary conditions constructed by means of complex geometrical optics solutions.