Sign verification

摘要

A method of determining whether the writer of a sign is the same as the writer of a previously written sign at least one characteristic feature of which has been prerecorded comprises: (a) detecting at least one characteristic feature of the written sign; (b) comparing the or each detected feature with the corresponding prerecorded feature (s); (c) generating an acceptance signal if all differences between the detected and the prerecorded features lie within first predetermined limits; (d) if an acceptance signal cannot be generated, obtaining one or more further written signs (up to a predetermined maximum) and repeating steps (a) to (c) with the or each further written signs; (e) if an acceptance signal cannot be generated for the or any of the further written signs, comparing the differences between the characteristic features of each written sign and the corresponding characteristic of the prerecorded sign and, if all the differences fall within second predetermined limits; (f) comparing corresponding characteristic features of the written signs and generating an acceptance signal if all differences between the features lie within third predetermined limits.