Patent ID: 6195460
Filing Date: 2001-02-27
Classification: G06K

Abstract:
A pattern extraction apparatus characterized by comprising:registration Fourier pattern data generating means for generating registration Fourier N-dimensional pattern data by performing N-dimensional discrete Fourier transform for N-dimensional pattern data of a registration pattern;collation Fourier pattern data generating means for generating collation Fourier N-dimensional pattern data by performing N-dimensional discrete Fourier transform for N-dimensional pattern data of a collation pattern;first pattern processing means for performing one of the N-dimensional discrete Fourier transform and N-dimensional inverse discrete Fourier transform for synthesized Fourier N-dimensional pattern data obtained by synthesizing the registration Fourier N-dimensional pattern data generated by said registration Fourier pattern data generating means and the collation Fourier N-dimensional pattern data generated by said collation Fourier pattern data generating means;mask processing means for obtaining a correlation peak in a correlation component area appearing in the synthesized Fourier N-dimensional pattern data for which the Fourier transform has been performed by said first pattern processing means, andmasking a predetermined area including the obtained correlation peak;second pattern processing means for performing the N-dimensional inverse discrete Fourier transform for the synthesized Fourier N-dimensional pattern data in which the predetermined area is masked by said mask processing means when the N-dimensional discrete Fourier transform is performed for the pattern data by said first pattern processing means, and performing the N-dimensional discrete Fourier transform for the pattern data when the N-dimensional inverse discrete Fourier transform is performed for the pattern data by said first pattern processing means; andthird pattern processing means for performing the N-dimensional inverse discrete Fourier transform for re-synthesized Fourier N-dimensional pattern data generated by re-synthesizing the synthesized Fourier N-dimensional pattern data for which the Fourier transform has been performed by said second pattern processing means and the registration Fourier N-dimensional pattern data generated by said registration Fourier pattern data generating means.