Simultaneous Reconstruction of Absorption and Scattering Distributions in Turbid Media using a Born Interative Method

Y. Yao et al. (1995)

Summary

In this paper, we present a Born Interative Method for imaging optical properties of turbid media using frequency–domain data. In each iteration, the incident field adn the associated weight matrix are first recalculated based on the previous reconstructed image. A new estimate is then obtained by solving the updated perturbation equation. The forward solution of the incident field is obtained by a multigrid finite difference method. The inversion is carried out through a Tikhonov regularized optimization process using the conjugate gradient descent. Using this method, the distribution of the complex wavenumbers in a test medium is first reconstructed, from which the absorption and scattering distributions are then derived. Simulation results have shown that this method can yield quantitatively quite accurate reconstruction even when a strong perturbation exists between the actual medium and an assumed homogeneous background medium, in which case the Born approximation cannot work well. Both full-angle and limited angle measurement schemes have been simulated to understand the effect of the location of detectors and sources.