Priority subband image coding

In this paper a new approach based on the subband decomposition (SBD) for compression and progressive transmission of images is presented. The novelty of this approach is that the transform coefficients of all image subbands are coded and transmitted in absolute magnitude order. The ordered-by-magnitude transmission is accomplished by using partition priority coding (PPC) a new source coding method that allows the simultaneous transmission of the coefficients of a data set in an ordered fashion along with position information. Using this approach, coding and transmission are adaptable to the characteristics of each individual image and therefore very efficient. Another advantage of this approach is its high progression effectiveness. Since the largest transform coefficients that capture the most important characteristics of images are coded and transmitted first this method is well suited for progressive image transmission (PIT). Further compression of the image data is achieved by adaptive multiple subsources distribution technique based on arithmetic coding. Experiments are presented where the new SBD approach was tested. It is shown that it compares favorably with previously reported discrete cosine transform (DCT) and subband image codecs and is also very effective for progressive image transmission.