Medical imaging with nonlinear waveform inversion (NLWI) system using recurrent neural network

A system for recovering physical properties from a non-linear medium, the system comprising:

• a wave field modeler to model a wave field generated by at least one transmitted pulse as it travels in said non-linear medium and to generate a predicted transducer output from said modeled wave field, said wave field modeler being implemented as a recurrent neural network (RNN) wherein each layer of the RNN corresponds to a discrete time step of the wave propagation and implements a discrete version of a physics-based non-linear wave equation using an initial set of physical properties of the medium-;
• a properties adjuster to iteratively update the set of physical properties by:
• receiving a loss function value representing a difference between the predicted transducer output and a measured transducer output;
• and
• operating a backpropagator through said RNN to adjust the set of physical properties to minimize the loss function, thereby generating an improved set of said physical properties for a subsequent iteration of said wave field modeler;
• and
• a medium properties recoverer to output a final improved set of said physical properties once said properties adjuster reaches a convergence criterion, wherein said final set of physical properties constitutes said recovered physical properties of said non-linear medium.