Progressive Image Transmission by Content Driven Laplacian Pyramid Encoding

Progressive image transmission is quite effective in those applications where the user can decide whether to stop the transmission at a given resolution or to continue the image retrieval up to the finest level of detail. In the framework of an efficient encoding scheme, compression can be increased, maintaining the same quality, when some criterion is applied to find out and transmit first the high-detailed image areas. To this aim, we propose two criteria which are applied in a Laplacian pyramid (LP)-based encoding scheme. One of them selects the areas of the LP where the zero crossings (ZC) exceed a threshold, the other chooses the areas of the LP where the energy is high. Our results show that image transmission according to the above priority criteria gives advantage over plain breadth-first pyramid expansion, not only subjectively but also quantitatively. Comparison curves are reported.