Ognyan Ivanov Zhelezov was born in Novi Pazar, Bulgaria, in 1952. He received the B.S. and M.S. degrees in Radio Engineering from the Technical University of Varna (TU-Varna), Bulgaria, in 1977 and the PhD degree in Nikola Vaptsarov Naval Academy of Varna, Bulgaria, in 1990. Since 1988 to 1999, he has been an Assistant Professor and since 2000 to 2011 – Associate Professor with the Computer Science Department, TU-Varna, Bulgaria. Now retired, he works as apart-time lecturer in Nikola Vaptsarov Naval Academy, Varna, Bulgaria. His research interests include Applied Mathematics, Image Processing and Reversible Calculations.