N corresponds to bits per pixel, standard deviation was directly
related to contrast enhancement, i.e. when standard deviation (s)
was small, low contrast was noticed, and high contrast, when
standard deviation was large. The gmax and gmin were referred to
as the whole image maximum and minimum intensity values;
mean (m) and standard deviation (s) within each window provided
considerable contrast enhancement.
The processed image (IF) was binarised by a locally adaptive
binarisation method. The outcome was actualised by pixel value
transformation to one, provided that the value was larger than the
mean intensity (M) value of the present block (1616) to
which the pixel adhered and the binary image (IB) resulted as
follows: