A lowcomplexity speck-based codec for multispectral fluorescence microscopic images

Abstract

The distortion scalable wavelet based coder SPECK is widely referred to in literature as achieving excellent coding performance with very low computational complexity compared to other state-of-the-art encoders. In this paper, we propose a 3D extension to SPECK designed for lossless coding of low-SNR fluorescence microscopic multispectral images by joining and encoding together different wavelet subbands. The idea is based on an observation that in comparison to other image types, fluorescence images have a larger proportion of energy concentrated in the lowest frequency subbands, whereas the energy inside higher frequency subbands constitute a considerably small portion. Also, subbands at the same level of wavelet-transformed image are found to be highly correlated. Consequently, encoding higher subbands by grouping them together in a single block results in a considerable bit saving. In order to maximize the block size of coefficients that can be encoded together, a new set type is introduced. The proposed technique applied to test multispectral microscopic images demonstrates a significant bit savings.Index Terms-3D SPECK, fluorescence imaging, multispectral imaging, microscopic image encoding, low-SNR image encoding.