Abstract: A method of operating a pattern recognition apparatus comprises generating a plurality of sub pixel sub signatures from a reference signature, wherein the sub pixel sub signatures correspond to fractional pixel (sub pixel) positions. A target sub signature is compared to each of the sub pixel sub signatures to determine the relative placement of a target object to within a fraction of a pixel.

Abstract: A method of operating a pattern recognition apparatus comprises generating a plurality of sub pixel sub signatures from a reference signature, wherein the sub pixel sub signatures correspond to fractional pixel (sub pixel) positions. A target sub signature is compared to each of the sub pixel sub signatures to determine the relative placement of a target object to within a fraction of a pixel.

Abstract: A wire bonding apparatus and method incorporating a pattern recognition system wherein there is stored, in a teach mode, signatures representing a pre-determined point on a chip to be bonded, the signatures being obtained at respective 90.degree. locations of the pedestal which carries the chip. Automatic re-calibration provides for rotating the pedestal to each of four 90.degree. apart spaced angles and finding the respective recorded signatures and the corresponding positions, and calculating the true center of rotation as a function of the four positions thus found. A specialized algorithm is used for correcting error which may be introduced if the chip is not rotated at precisely 90.degree. intervals during the process of finding the respective signatures. The system carries out re-calibration automatically every N packages bonded.

Abstract: An improved pattern recognition system is disclosed which converts rows and columns of digitized video signal elements indicative of light intensity falling on a camera into integrated signatures, one for each of two orthogonal directions. Signatures corresponding to effectively rotated images may also be provided. Portions of the signatures having the most useful information contained therein are selected by comparison with subsets of the total signatures in a teach mode. In a run mode, the thus selected sub signatures are compared with snapshot signatures of a target object, such as integrated circuit dice, for precise location of corresponding portions of the target object.