1. Centre of Signal and Image Processing, Faculty of Computer Science & Information Technology, University of Malaya, 50603 Kuala Lumpur, Malaysia
2. Department of Computing Science, and Institute of Complex Systems & Mathematical Biology, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen, AB24 3UE, U.K.
3. Intelligent Systems & Biomedical Robotics Group, School of Creative Technologies, University of Portsmouth, Portsmouth, PO1 2DJ, U.K.