The images are read in buffers for memory considerations. First complex interferogram is computed as in INTERFERO. and the norms of the master and slave images are computed.
Then a shifting window of size COH_WINSIZE is used to estimate the complex coherence (see Annex D).
The coherence is computed with a function of the matrix class. This function returns only the lines of the input which can be computed due to the edge of the the estimator window. Then this is multilooked (requires number of lines to be a multiple of the multilook factor)
Therefore, the buffer should contain an overlap with the previous one.