Figure 8.

Memory management in the merging step. The whole volume is processed a layer at the time, each composed by the number of slices needed to generate the lowest resolution (e.g. 32 slices for a reduction of 5 times). For each layer, stacks are read row-wise and merging is performed slice by slice. When one slice group of every tile in row i of the tile matrix have been read, adjacent tiles in the groups are merged using the blending algorithm described in the Algorithms section. This produces a horizontal stripe, which is merged with the ones previously generated from the slices of the preceding rows, so producing larger stripes until the whole slice of the final image representation is obtained.