A new method for implementing moment functions in a CMOS retina

We present in this paper a new method for implementing geometric moment functions in a CMOS retina. The principle is based on the similarity between geometric moment equations and the measurement of the correlation value between an image to analyze and a range of grey levels. The latter is approximated by a binary image called mask using a dithering algorithm in order to reduce hardware implementation cost. The correlation product between the mask and the image under analysis gives an approximated value of the geometric moment with an error less than 1% of the exact value. Finally, the results obtained by our approach have been applied to an object localization application and the localization error due to the approximated moment values reported. Olivier Aubreton was born in Vichy on August 31, 1973. He obtained the agrégation examination in June 2000 and received the D.E.A. degree (equivalent to a master degree) in image processing in June 2001. He is currently a lecturer working towards a Ph. D. degree at Laboratory LE2I in the IUT of Le Creusot in Burgundy. His research interests include the design, development implementation, and testing of silicon retinas for pattern matching and pattern recognition. Lew F.C. Lew Yan Voon received his Ph.D. degree in Computer Aided Design of VLSI circuits from Montpellier University, France, in March 1992. Since September 1993, he has been first assistant professor and then associate professor at the University of Burgundy. His research interests lie in the field of pattern recognition and in the design of silicon retinas in standard CMOS technology for real-time inspection by machine vision. Bernard Lamalle was born in Autun on May 1, 1946. He obtained the Ph.D. degree in 1973 from the Université de Bourgogne in Dijon. During 1980 to 2000 he has been Maître de conférences at the IUT of Le Creusot in Bourgogne. He joined the image processing team of laboratory Le2i in 1992. Since 2000, he has been appointed full professor of the University of Bourgogne. His field of interest is principally the study and design of silicon retinas dedicated to industrial control. He has in charge some industrial contracts in the field of quality control by artificial vision and he holds two patents in the field of image processing and smart sensors. Guy Cathébras was born in Uzès, France, in 1961. He received the French engineer degree from the Ecole Nationale Supérieure de l'Electronique et de ses Applications, Cergy, France, in 1984 and the Diplôme de Doctorat de l'Université de Montpellier, France, in 1990. Since 1992 he is an assistant professor of microelectronics at the Institut des Sciences de l'Ingénieur de Montpellier. His current research interests include the design of imagers and silicon retinas using standard CMOS technologies.