Patent ID: 7773811

Claim:
A method for searching a database of graphical data, said data including a plurality of reference images, comprising: (a) generating a matrix of similarity scores of the reference images, each reference image forming a unity diagonal matrix element and similarity scores of the reference images one versus another forming non-diagonal matrix elements; (b) determining a similarity score of a query image versus a reference image; (c1) if the similarity score defined at the step (b) is greater than a pre-selected threshold: determining that the query image and said reference image are graphically identical; (c2) if the similarity score defined at the step (b) is smaller than the pre-selected threshold: defining, in a row or a column intersecting a diagonal of the matrix at a position relating to said reference image, a matrix element having a closest similarity score with said reference image; (d) determining a similarity score of the query image with a reference image used for generating the matrix element defined at the step (c2); (e1) if the similarity score defined at the step (d) is greater than the pre-selected threshold: determining that graphical contents of the query image and the reference image of the step (d) are graphically identical; and (e2) if the similarity score defined at the step (d) is smaller than the pre-selected threshold: cyclically repeating the steps (c1) through (e1) and replacing in each cycle a preceding reference image with a reference image used to generate a matrix element having, in a row or a column intersecting a diagonal of the matrix at a location relating to the preceding reference image, a closest similarity score with the preceding reference image; and identifying the reference images which similarity scores with the query image are greater than the pre-selected threshold as graphically identical with the query image, wherein the similarity score is defined as a complement to a pictorial edit distance, which is asserted as a weighted sum of a 2D representation of Insertion, Deletion, and Substitution Error terms of the Levenshtein algorithm for matching or searching one-dimensional data strings.