Low bit rate subband DCT image compression

This paper describes two novel methods to improve the efficiency of subband coding by means of the energy compactness in the frequency domain. Our coding scheme applies a variable block size DCT to the subband signal to get a high coding efficiency. A class driven segmentation is devised as a variable block partition scheme. Besides, an information oriented coding strategy without side information is developed. The strategy not only retains the image properties but also reduces the computation overhead. Simulations are carried out to the Lena image, and their results show the effectiveness of the two approaches especially for low bit rate applications.