Maximizing entropy of image models for 2-D constrained coding

This paper considers estimating and maximizing the entropy of two-dimensional (2-D) fields with application to 2-D constrained coding. We consider Markov random fields (MRF), which have a non-causal description, and the special case of Pickard random fields (PRF). The PRF are 2-D causal finite context models, which define stationary probability distributions on finite rectangles and thus allow for calculation of the entropy. We consider two binary constraints and revisit the hard square constraint given by forbidding neighboring 1s and provide novel results for the constraint that no uniform 2 £ 2 squares contains all 0s or all 1s. The maximum values of the entropy for the constraints are estimated and binary PRF satisfying the constraint are characterized and optimized w.r.t. the entropy. The maximum binary PRF entropy is 0.839 bits/symbol for the no uniform squares constraint. The entropy of the Markov random field defined by the 2-D constraint is estimated to be (upper bounded by) 0.8570 bits/symbol using the iterative technique of Belief Propagation on 2 £ 2 finite lattices. Based on combinatorial bounding techniques the maximum entropy for the constraint was determined to be 0.848

Optimization of high-definition video coding and hybrid fiber-wireless transmission in the 60 GHz band

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.00B895. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] The paper addresses the problem of distribution of highdefinition video over fiber-wireless networks. The physical layer architecture with the low complexity envelope detection solution is investigated. We present both experimental studies and simulation of high quality high-definition compressed video transmission over 60 GHz fiberwireless link. Using advanced video coding we satisfy low complexity and low delay constraints, meanwhile preserving the superb video quality after significantly extended wireless distance. © 2011 Optical Society of America.This work has been partly funded by the European Commission under FP7 ICT-249142 FIVER project and by the by the Spanish Ministry of Science and Innovation under the TEC2009-14250 ULTRADEF project.Lebedev, A.; Pham, T.; Beltrán Ramírez, M.; Yu, X.; Ukhanova, A.; Llorente Sáez, R.; Monroy, I.... (2011). Optimization of high-definition video coding and hybrid fiber-wireless transmission in the 60 GHz band. Optics Express. 19(26):895-904. https://doi.org/10.1364/OE.19.00B895S8959041926Stockhammer, T., Hannuksela, M. M., & Wiegand, T. (2003). H.264/AVC in wireless environments. IEEE Transactions on Circuits and Systems for Video Technology, 13(7), 657-673. doi:10.1109/tcsvt.2003.815167Yong, S. K., & Chong, C.-C. (2006). An Overview of Multigigabit Wireless through Millimeter Wave Technology: Potentials and Technical Challenges. EURASIP Journal on Wireless Communications and Networking, 2007(1). doi:10.1155/2007/7890