“…In the local adaptive technique, a threshold is calculated for each pixel, based on some local statistics such as range, variance, or surface-fitting parameters of the neighboring pixels. It can be approached in different ways, such as background subtraction (Lu et al, 2010), water flow model (Oh et al, 2005), mean and standard derivation of pixel values (Sauvola and Pietikäinen, 2000) and local image contrast (Su et al, 2010). Some drawbacks of the local thresholding techniques are region size dependant, individual image characteristics, and time-consuming.…”