from the article:

MIC and the other MINE statistics are calculated from a matrix of scores generated from a given set of two-variable data. This matrix, called the characteristic matrix, is created by searching for grids that maximize the penalized mutual information of the distribution induced on each grid’s cells by the data. Different relationship types give rise to characteristic matrices with different properties. For instance, strong relationships yield characteristic matrices with high peaks, monotonic relationships yield symmetric characteristic matrices, and complex relationships yield characteristic matrices whose peaks are far from the origin.