Method in creating a symbol pattern, symbol pattern obtained thereby, method and system for finding a position in such symbol pattern and computer program product for performing the method

摘要

The invention relates to a method in creating a two-dimensional symbol pattern which may be utilized to determine a position in a large area covered by the pattern, for example for recording handwritten information by means of a pen-like instrument. The invention is useful for creating a symbol pattern having desired properties, namely that any sufficiently large observed part of the pattern is unique, enabling an unambiguous determination of position. The symbol pattern is based on a non-repeating sequence of symbol values S_k that each corresponds to a fixed linear combination of the coefficients of the monomials in x^k mod P(x), where P(x) is any polynomial of degree n in the field F_q. The symbol pattern is generated by folding the sequence according to a wrapping scheme. The invention also relates to methods and systems for finding the position of a group of observed symbol values in this symbol pattern and computer program products performing the methods.