Hierarchical image representation by mathematical morphology subband decomposition

An efficient subband image decomposition method by mathematical morphology has been proposed recently. This method decomposes the input signal spectrum into 4 subbands by using two separable structuring elements. Based on this method, a hierarchical image representation referred to as subband pyramid is described. This subband pyramid scheme preserves the number of pixels as in the original image, also the data structure itself is very compact. More importantly, morphological filtering manipulates the specific shape in the image, it only alters certain geometric details without affecting the remaining image structure. When the resolution is reduced, no overall blurring is introduced in the image as the conventional linear filtering method does. This natural decomposition of multiple scale shapes might be a useful hierarchical representation for the images.