A method of compressing a current image of a sequence of images is
disclosed. Firstly, the current image is transformed with a predetermined
transform such as the DWT to provide a set of transform coefficients
(step 2202). The method then retrieves (step 2303), for at least one
transform coefficient of a current image, a predetermined number of bits,
preferably two, of a corresponding transform coefficient of a previously
compressed image of the sequence. The corresponding transform coefficient
is truncated at a truncation bitplane and the retrieved bits are the
least significant bits of the truncated corresponding transform
coefficient. The transform coefficient of the current image is set to a
new value that is a function of the retrieved bits (step 2306) and bits
of the transform coefficients of the current image are stored for use in
compressing one or more subsequent images of the sequence (step 2208).