High Speed, Low Memory Image Coding Using Zero blocks of Wavelet Coefficients

We propose a new high speed, low memory SPECK image coder based on the form of block-unit states, called LBUS-SPECK, which uses the form of block-unit states and the form of block exponents to substitute LIS and LSP of SPECK. A form of block-unit states is introduced to store the significance flag of coefficients and the value of the block-unit exponents. A form of block exponents is introduced to store the block exponents which are used to represent the max coefficient in a decomposed block. A new block depth-finding strategy is developed for searching insignificant sets at sorting stage. Experimental results show that the obtained PSNR values for the decoded images are very close to those of SPECK algorithm and the memory consumption is reduced by 9 times, the encoding timing is saved about 15%. Comparing with SPECK algorithm, this algorithm not only has better performance of the decoded images, but also is easy to implement, especially, it provides an efficient way for hardware implementation of wavelet embedded block coding.