Patent ID: 6687824
Filing Date: 2004-02-03
Classification: G06T,H04N

Abstract:
A digital image coding apparatus for recording a signature image on a host image using watermarking, comprising:a first discrete wavelet transform portion operative to receive a host image and perform discrete wavelet transform thereon, and output MÃ—M discrete wavelet coefficients where M is a predetermined positive integer; a second discrete wavelet transform portion operative to receive a signature image and perform a discrete wavelet transform thereon, and output NÃ—N discrete wavelet coefficients, where N is a predetermined positive integer smaller than M; a pseudo-random number generator operative to receive an encryption code for determining a predetermined rule for generating pseudo-random numbers and generate the pseudo-random numbers in accordance with the predetermined rule corresponding to the encryption code; and a coefficient replacement portion operative to select the replacing locations of NÃ—N pixels using the pseudo-random numbers, and replace the coefficients of the selected NÃ—N pixel locations among MÃ—M discrete wavelet coefficients with NÃ—N wavelet coefficients, and output replaced MÃ—M wavelet coefficients.