Concepts inA System of Subroutines for Iteratively Reweighted Least Squares Computations
Iterative reconstruction refers to iterative algorithms used to reconstruct 2D and 3D images in certain imaging techniques. For example, in computed tomography an image must be reconstructed from projections of an object. Here, iterative reconstruction techniques are a better, but computationally more expensive, alternative to the common filtered back projection (FBP) method, which directly calculates the image in a single reconstruction step.
more from Wikipedia