Patent ID: 6332030
Filing Date: 2001-12-18
Classification: G06T

Abstract:
A method for embedding a signature image in a host image, comprising:(a) performing a single level discrete wavelet transform decomposition of said signature image and said host image;(b) quantizing into .beta. levels each coefficient of said signature image by grouping a set of n coefficients in the host image to form an n-dimensional vector, and perturbing said vector according to a .beta.-ary channel code comprising a subset of an n-dimensional lattice scaled by a factor .alpha.;(c) embedding each subband of said signature image into a corresponding subband of said host image to produce a composite image;(d) subtracting the coefficients of said host image from the coefficients of the composite image to obtain noisy perturbations;(e) grouping the resulting coefficients into groups of n to obtain a vector e;(f) scaling said vector e by 1/.alpha. to produce a resulting vector 1/.alpha..multidot.e;(g) nearest-neighbor encoding 1/.alpha..multidot.e to find an index i of the channel code nearest to it in Euclidean distance;(h) obtaining a quantized discrete wavelet transform coefficients from said index i.