Patent ID: 6424729
Filing Date: 2002-07-23
Classification: G06K

Abstract:
A method for assessing the authenticity of a target image, said method comprising the steps of:a) detecting and electronically storing a joint power spectrum of optical signals corresponding to a Fourier transform of a joint input scene, said joint input scene comprising said target image and a plurality of reference images; b) detecting and electronically storing a target-only power spectrum of optical signals corresponding to a Fourier transform of said target image; c) electronically storing a reference-only power spectrum of optical signals corresponding to a Fourier transform of said plurality of reference images; d) using a computer to subtract said reference-only power spectrum and said target-only power spectrum from said joint power spectrum to form a modified power spectrum; e) detecting and electronically storing a cross-correlation pattern of optical signals corresponding to a Fourier transform of a displayed image of said modified power spectrum; f) determining maximum cross-correlation peak values of cross-correlation peaks occurring in said cross-correlation pattern-corresponding to said modified power spectrum; and g) comparing each of said maximum cross-correlation peak values to a corresponding verification value which is the maximum peak value of an auto-correlation of corresponding reference image with itself; wherein if one of said maximum cross-correlation peak values falls within a specified range of said corresponding verification value, said target image is authenticated.