ReadImageAsFilteredPureCubicalComplex(str,n):: String, Int --> FilteredPureCubicalComplex

Reads an image file identified by a string str such as "file.bmp", "file.eps", "file.jpg", "path/file.png" etc., together with a positive integer n. It returns a 2-dimensional filtered pure cubical complex of filtration length n. The kth term in the filtration is a pure cubical complex corresponding to a black/white version of the image determined by the threshold t_k=k \times 765/n . The 2-cells of the kth term correspond to pixels with RGB value R+G+B \le t_k.