Conceptually, layer stripping amounts to solving for the conductivity distribution layer by layer, like peeling an onion. The current and voltage measurements, which are made on the outside surface, are used directly to solve for the conductivity of the first layer. From this solution, a set of currents and voltages are computed for the inside surface of this layer. The nice thing is, it applies to lots of problems. The RPI researchers are not the only group working on impedance imaging, but Cheney credits Isaacson with having the clearest vision of what can be done.
People working on inverse problems usually start by thinking about the reconstruction problem.
Figuring out what data one needs in order to do reconstruction often suggests what measurements should be made. But Dave looked at the problem from the point of view of actually building a system, and asked the more fundamental question of how to make measurements containing the maximum amount of information. The answers could wind up saving lives.