Patent ID: 8116553

Claim:
A method for determining a descriptor that encodes information about the shape of a two-dimensional sketch, the method performed by a computer and comprising: creating a first circle defined by a center of gravity of the sketch and a radius which is the taken to be the maximum distance of any point on the sketch to the center of gravity; subdividing the first circle into a plurality of circular sectors; creating a plurality of other circles concentric with and smaller than the first circle; creating a set of points uniformly distributed over the sketch; calculating a minimal distance from each of the plurality of points contained in each of the plurality of circular sectors to the arcs of the plurality of other circles in that circular sector; determining a periodic function for each of the plurality of circles defined by the calculated minimal distances to the arcs of the respective circles; representing the periodic functions using a Discrete Fourier Transform; creating a two-dimensional array of Fourier coefficients corresponding to each of the plurality of functions; and storing the two-dimensional array as a rotation-invariant descriptor that uniquely identifies the two-dimensional sketch for efficient retrieval and use in product design and product data management processes.