Synthesis filterbank with low hardware complexity for subband image coding

Different algorithms are evaluated and optimizations are performed to obtain a filterbank for subband coding of images especially suited for very large scale integration (VLSI) implementation. Based on a filterbank consisting of two finite impulse response (FIR) filters combined with an 8-point discrete cosine transform (DCT), we investigate how the quantization of filter coefficients and twiddle factors in different algorithms affects the quality of the filterbank. It is found that a DCT based on a Stasinksi algorithm with twiddle factors of only 5 b together with FIR filter coefficients of 10 b gives a filterbank with high coding gain, no blocking artifacts, and limited ringing. The VLSI complexity is comparable to that of DCT transforms.