Abstract—In this paper, Slepian-Wolf coding is considered for compression of facsimile images. The correlation between the image scan lines is exploited at the decoder using Slepian-Wolf coding (SWC). The side information is generated at the decoder using previously decoded image lines and context modelling. A novel weighted context-based iterative decoding of low density parity check (LDPC) codes is proposed in addition to realizing context-based initialization of log-likelihood ratio values in LDPC iterative decoding. On an average, an increase of 0.60 in the compression ratio is obtained with the context modelling. As the proposed method is based on SWC principles, it is inherently error resilient and affords a system with a low-complexity encoder.
Index Terms—Facsimile, LDPC, Context-Modelling, Nonuniform Source, Slepian-Wolf Coding, DSC.
Raghunadh K Bhattar is with EE Dept-IISc, Bangalore and SNAA-SACISRO, Ahmedabad. India (email: k_raghunadh@rediffmail.com)
Prof. K. R. Ramakrishnan is with EE Dept-IISc, Bangalore, India.(krr@ee.iisc.ernet.in)
Prof. K. S. Dasgupta is with IIST Thiruvananthapuram, India(ksdasgupta@yahoo.com) and was formaly with SNPA/SAC/ISRO, Ahmedabad, India.
Cite: Raghunadh K. Bhattar, K. R. Ramakrishnan, and K. S. Dasgupta, "Facsimile Image Compression using Slepian-Wolf Coding Principles and Context Modelling," International Journal of Information and Electronics Engineering vol. 1, no. 2, pp. 157-162, 2011.