A device for decomposing images into at least three levels by wavelet transform comprises a first unit executing a first level of decomposition and a second unit executing the higher levels of decomposition by performing a sequence of processing tasks. The tasks are ordered in time by using a sequence of rows, a routing unit serving to configure the second unit when the level of decomposition associated with the processing task currently being executed changes relative to the level of decomposition associated with the processing task executed previously. The processing tasks are ordered so that any given row is associated with only one level of decomposition.