Polyphase structures for multiplierless biorthogonal filter banks [image compression applications]

Design techniques for high performance, fixed-point, multiplierless filter banks are presented. A technique is developed for designing a fixed-point polyphase filter structure such that the hardware is highly efficient and the image compression quality is minimally impacted by the use of fixed-point mathematics. Image compression using the biorthogonal 9/7 discrete wavelet transform provides a motivating example. The results show that the implemented structure has a significant impact on the resulting hardware cost, throughput, and compression quality. We achieve a polyphase structure with twice the throughput rate of non-polyphase structures and image compression fidelity within 0.2 dB of the unquantized, floating-point filters.