Patent ID: 6226417
Filing Date: 2001-05-01
Classification: G06K,G06T

Abstract:
A method of determining a rotational angle of an image pattern having an outer boundary, comprising:inputting an input image pattern and a radial polynomial table containing sets of Zernike Moment (ZM) intermediate values for a predetermined specific size of the input image pattern, each set containing the ZM intermediate values each at a predetermined rotational angle for a predetermined periodicity;determining a plurality of Zernike Moment (ZM) values by multiplying a predetermined set of the ZM intermediate values by pixel values at predetermined equidistant locations from a center of the input image pattern;assigning an evaluation value for each of the ZM values by multiplying the ZM value and a corresponding periodicity; anddetermining a rotational angle of the input image pattern based upon a largest one of the evaluation values.