The invention concerns a method and a device to determine a descriptor for a signal representing a multimedia item. The method comprises the step of applying to said signal a first bank of directional filters in order to obtain a first set of coefficients. According to the invention the method comprises the steps of: applying to said signal a second bank of filters in order to obtain a second set of coefficients representing the low-pass filtered signal, calculating a descriptor representing said multimedia element by making the difference between said first set of coefficients and said second set of coefficients and calculating associated power of said difference. Application to the classification and retrieval of multimedia items.