1. A method for synthesizing noise in a digital image comprised of a plurality of color channels, where the noise is used to represent a synthetic texture that visually approximates a predetermined appearance, said method comprising the steps of: (a) estimating noise statistics based on a set of spatial autocorrelation coefficients and a set of spectral correlation coefficients that correspond to the color channels, where at least one of the spatial autocorrelation coefficients is weighted by at least one of the spectral correlation coefficients, thereby providing a weighted set of autocorrelation coefficients, and where filter coefficients are obtained from the weighted set of autocorrelation coefficients; and (b) synthesizing a synthetic texture by using the filter coefficients to filter a random noise field in each of the color channels, thereby producing output noise fields in each of the color channels that replicate the synthetic texture when combined into the digital image.