1. Department of Mathematics and Computer Science; University of Bielsko-Biała; ul. Willowa 2, 43-309 Bielsko-Biała Poland
2. Department of Electrical and Computer Engineering; North Dakota State University; Fargo ND, 58108-5060 USA
3. Center for Earth Observation and Digital Earth; Chinese Academy of Sciences; China
4. School of Information Technologies; University of Sydney; Sydney NSW 2006 Australia