Abstract
In this paper, a hybrid image coding scheme is proposed for progressive transmission of images over a digital cellular channel. The hybrid image coder decomposes an image using wavelet filters into multiple pyramid layers, which are further decomposed using subband coding. The bands are coded using vector quantization (VQ). The hybrid image decomposition scheme employs the concept of feedback to retrieve the information lost due to coding. The bands are transmitted according to the descending order of their respective entropies. The North American digital cellular standard (IS-54) has been used as the wireless communication environment. Application of the proposed scheme is investigated for vehicle speeds of 0.1 mph and 60 mph with a channel signal-to-noise ratio of 22 dB. Simulation results using a standard test image show the significant advantage of the proposed technique over the existing algorithms in terms of low bit rare and good image quality.