An Adaptive Significant Bit Coding Algorithm

In JPEG2000, significant bit coding performs the main part of bitplane coding. Scan strategy of wavelet coefficients, which directs coder to generate good autocorrelation significant bit sequence, is one of the key factors to conduce to high compression ratio. Stripe scan is adopted by JPEG2000. Hilbert curve is one of popular space filling curves (SFC). However, the scan pattern of stripe scan and Hilbert curve scan is aptotic. They are neither image-dependent nor bitplane-dependent. An adaptive significant bit coding algorithm is proposed. Without changing the context template oj JPEG2000, the proposed scheme uses an explicit layer template to dynamically arrange the scan path of wavelet coefficients. Experimental results show that the proposed scheme provides output bitstream of better autocorrelation than stripe scan and Hilbert curve scan; after the same entropy coder, the proposed scheme conduces to higher compression ratio than stripe scan scheme and Hilbert curve scheme.