1. A method for wavelet transform coding a digital image, said method comprising: selecting a wavelet decomposition level; applying a first wavelet transform filter at said wavelet decomposition level to a first segment of a digital image, thereby obtaining a first set of transform coefficients; applying a second wavelet transform filter at said wavelet decomposition level to a second segment of said digital image, thereby obtaining a second set of transform coefficients; and merging said first and second sets of transform coefficients into a composite wavelet coefficient image.