24. A computer-implemented method of optical character recognition, comprising: receiving at a computer a plurality of proposed character assignments for at least one instance of a character in an image on which optical character recognition is being performed, the at least one instance of the character residing on an image, each character assignment representing a character determined from a character set for the at least one instance of the character by the optical character recognition; referring to a multiple-character reference character string containing the at least one instance of the character or another instance of the character and the reference character string known to exclude a subset of one or more characters of the character set based at least in part on the reference character string's location in the image; and eliminating at least one of the plurality of proposed character assignments by comparing the at least one of the proposed character assignments to the subset of one or more characters known to be excluded by the reference character string.
24. A computer-implemented method of optical character recognition, comprising: receiving at a computer a plurality of proposed character assignments for at least one instance of a character in an image on which optical character recognition is being performed, the at least one instance of the character residing on an image, each character assignment representing a character determined from a character set for the at least one instance of the character by the optical character recognition; referring to a multiple-character reference character string containing the at least one instance of the character or another instance of the character and the reference character string known to exclude a subset of one or more characters of the character set based at least in part on the reference character string's location in the image; and eliminating at least one of the plurality of proposed character assignments by comparing the at least one of the proposed character assignments to the subset of one or more characters known to be excluded by the reference character string. 40. The method of claim 24 wherein the image comprises a digitized document.