Parameter inference

Parameter inference#

Estimating tissue properties from a measured volume.

Every estimator is made from the simulator it inverts and fitted over the same statement of the problem – what is unknown, over what range, at what noise level – and they differ only in how they fill it in. These examples change only that: dictionary matching over a parameter grid, compressed and clustered; interpolation along a curve where there is a single unknown; a nonlinear fit of the model itself; and a kernel regression that never builds a grid at all.

Every one of them maps the same BrainWeb slice, so the answer is known everywhere – mixtures of tissues included – and reports what it cost in time and in memory alongside what it got wrong.

Dictionary matching

Dictionary matching

MP2RAGE lookup table

MP2RAGE lookup table

T2 mapping by nonlinear least squares

T2 mapping by nonlinear least squares

PERK: kernel ridge regression

PERK: kernel ridge regression