Multi-parameter acoustic imaging of uniform objects in inhomogeneous media

TL;DR

This paper develops a novel ultrasound imaging method that accounts for inhomogeneous media and background clutter, using statistical modeling and convex optimization to improve object classification accuracy.

Contribution

It introduces a multi-parameter acoustic imaging approach incorporating statistical interference models and total-variation minimization for better reconstruction in complex media.

Findings

Robust classification performance at low signal-to-clutter ratios

Effective reconstruction using convex optimization methods

Comparison shows improved results over minimum-l2-norm reconstruction

Abstract

The problem studied in this paper is ultrasound image reconstruction from frequency-domain measurements of the scattered field from an object with contrast in attenuation and sound speed. The case where the object has uniform but unknown contrast in these properties relative to the background is considered. Background clutter is taken into account in a physically realistic manner by considering an exact scattering model for randomly located small scatterers that vary in sound speed. The resulting statistical characteristics of the interference is incorporated into the imaging solution, which includes applying a total-variation minimization based approach where the relative effect of perturbation in sound speed to attenuation is included as a parameter. Convex optimization methods provide the basis for the reconstruction algorithm. Numerical data for inversion examples are generated by solving the discretized Lippman-Schwinger equation for the object and speckle-forming scatterers in the background. A statistical model based on the Born approximation is used for reconstruction of the object profile. Results are presented for a two dimensional problem in terms of classification performance and compared to minimum-l2-norm reconstruction. Classification using the proposed method is shown to be robust down to a signal-to-clutter ratio of less than 1 dB.