Fig. 5
An example of two adjacent reconstruction steps for a general two-dimensional case. Panels a, b correspond to obtaining the first approximation, and c, d correspond to iterative refinement. Although pixels are divided after the first approximation is obtained, here the pixel size is chosen to be the same for both cases in order to show mathematical similarity of the first approximation inference and refinement. Letter “X” denotes pixels for which the optimization problem will be stated (“unknown” pixels), digit “0” denotes pixels that will be completely ignored at the iteration (“irrelevant” pixels), and letter “V” denotes pixels whose values will be included in the optimization problem as known constants (“known” pixels). Dashed frame shows the core of the window, solid frame shows the whole window, the core, and the border
