Low complexity synthesis filter bank for subband coding of images

Optimizations are performed to obtain a filter bank for subband coding of images espescially suited for VLSI implementation. Based on a filter bank consisting of two FIR filters combined with an 8 point DCT, we investigate how the quantization of filter coefficients and twiddle factors in different algorithms affects the quality of the filter bank. It is found that a DCT based on the Stasinksi algorithm with twiddle factors of only 5 bits together with FIR filter coefficients of 10 bits, gives a filter bank with high coding gain, no blocking artifacts and limited ringing. The VLSI complexity is comparable to that of DCT transforms.