Estimation of the gradient system impulse response function (the perturbing function) by differentiation through the image reconstruction operation.
Code used for JuliaCon 2022 is in girf_estimator.jl.
Flux requires version 12.0. If you've updated Flux, please type ] add Flux@0.12.0
It also includes fast explicit reconstruction operators that might be memory inefficient but are trivial to differentiate through.
Will update as I go along...