This is a texture measure which can be useful for extraction built-up areas from panchromatic images (resolution about similar to the objects to be extracted).
It is computed as the minimum value of the Haralick contrast for a set of different offsets.
In the case of Spot5 images (5 m resolution), and in order to detect buildings ranging from 10 to 20 m, the selected offsets are: (1,-2), (1,-1), (2,-1), (1,0), (2,0), (0,1), (1,1), (2,1), (0,2), (1,2). The window size is 9x9 (radius 5), which gives a size of about 50 m. which corresponds to the minimum size for a settlement.
A Robust Built-Up Area Presence Index by Anisotropic Rotation-Invariant Textural Measure Pesaresi, M.; Gerhardinger, A.; Kayitakire, F.; Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of Volume 1, Issue 3, Sept. 2008 Page(s):180 - 192