Title: Hybrid colour medical image compression by CDF wavelet and cosine transforms

Authors: Hacene Ismail Boukli; Abdelhafid Bessaid

Addresses: Biomedical Laboratory, Department of Electrics and Electronics, University of Tlemcen, Tlemcen 13000, Algeria ' Biomedical Laboratory, Department of Electrics and Electronics, University of Tlemcen, Tlemcen 13000, Algeria

Abstract: In this research, we introduce an idea for retinographic medical colour image compression, this new technique hybrid between Discrete Wavelet Transform (DWT) and Discrete Cosinus Transform (DCT). In recent times, developing hybrid schemes for effective image compression has gained enormous popularity among researchers. This research paper presents a proposed scheme for medical image compression based on hybrid compression technique (DWT and DCT). The goal is to achieve higher compression rates by applying different compression thresholds for the wavelet coefficients of each DWT band (LL and HH) while DCT transform is applied on LL bands with preserving the quality of reconstructed medical image. The retained coefficients are quantised by using adaptive quantisation according to the type of transformation. Finally the entropy coding (variable shift coding) is used to encode the quantisation indices. Experimental results show that the coding performance can be significantly improved by the hybrid DWT-DCT algorithm.

Keywords: medical imaging; colour images; image compression; lossless compression; discrete cosinus transform; DCT; discrete wavelet transform; DWT; CDF 9/7; retinographic images; entropy coding; variable shift coding; image processing.

DOI: 10.1504/IJBET.2014.065633

International Journal of Biomedical Engineering and Technology, 2014 Vol.16 No.1, pp.1 - 13

Received: 15 Jul 2013
Accepted: 17 Jan 2014
Published online: 25 Apr 2015 *

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