Regularized full waveform inversion for low frequency ultrasound tomography with a structural similarity EIT prior

In previous work by Rueter et al., low frequency (10–750 kHz) ultrasound was shown to penetrate the lung, motivating its use as a nonionizing tomographic technique for pulmonary monitoring. Here, we present method regularized full waveform inversion low-frequency data. A novel structural similarity index metric (SSIM)-based regularization term is introduced that compares correlation of current sound speed iterate prior reconstruction computed electrical impedance tomography (EIT). Full reconstructions speeds from numerically simulated data with 0.1% additive Gaussian noise are computed, and results compared using Tikhonov regularization, total variation both terms combined SSIM-EIT term. The EIT voltage on same phantom one step Newton-Raphson high-pass filter regularizer. Reconstructions including converged fastest, an adaptive parameter provided most accurate reconstructions. then iterated computing USCT result prior, subsequent updated reconstruction.