The principle of subband coding of images has been studied intensively for years. In our work on subband coding of images we have focused on a particular IIR filter bank structure that produces complex valued subband signals.
In previously reported coders, data compression is achieved as a result of scalar quantization or vector quantization (VQ) of the encoder subband signals (This also applies to the transform coefficients in a transform coder.)
In this paper we present new results pertaining to the quantization of the complex valued subband signals employing a new two dimensional (2-D) scalar quantizer. In the new quantizer we assume the signal to be 2-D vectors represented on polar form. The new quantization scheme can be applied to any signal provided the signal samples are statistically independent and grouped in 2-D vectors. The quantizer performs close to that of VQ in terms of SNR, where as it is characterized by the low computional complexity of scalar quantizers.