scanner but other scanners such as full color scanners may be employed scanner 2 may be part of optical character recognition ocr computer 1 or it may be a physically separate unit because of these two possibilities scanner 2 is shown partially enclosed within dashed lines in fig1 the output of scanner 2 is an array of numerical values which could be viewed as a set of scan lines 3 each of which illustrates greyscale level as a function of horizontal position along the page 20 the number of scan lines 3 per character on page 20 varies as a function of character size scanner 2 resolution etc and is typically about 60 scan lines per character in size 12 typefaces the number of levels of greyscale varies based upon the characteristics of scanner 2 and is typically 256 with such a greyscale resolution we assume without loss of generality that level 255 represents pure black while level zero represents pure white three exemplary scan lines 3 are illustrated in fig2 a 2b and 2c fig2 a illustrates a scan line 3 with a weak merge 40 and its separation threshold t fig2 b illustrates a scan line 3 with a moderate merge 40 and its separation threshold t fig2 c illustrates a scan line 3 with a strong merge 40 and its separation threshold t the horizontal axes in fig2 a 2b and 2c correspond to the horizontal axis of page 20 and are broken up into a discrete number of pixels depending upon the resolution of scanner 2 each of the scan lines 3 in fig2 a 2b and 2c is taken from a pair of touching characters the boxed regions 41 represent areas of thin strokes within the characters.