The algorithm to be presented moreover has the following attractive properties.
1. It only requires the solution of a single boundary value problem over the entire image domain -- almost always a very simple (rectangular) region.
2. It converges to the solution of interest.
The first of these properties implies very significant advantages over other existing regularization methods; the computation cost is typically cut by an order of magnitude or more. The second property represents considerable advantages over the existing diffusion methods; it removes the problem of deciding when to stop, as well as that of actually stopping the diffusion process.