Statistical Recursive Filtering Estimation of Detector Offset Nonuniformity in Infrared Imaging Systems ⋆ C´ esar San Martin 1,2 and Sergio N. Torres 1 1 Department of Electrical Engineering, University of Concepci´on. Casilla 160-C, Concepci´on, Chile cesanmartin@udec.cl, sertorre@udec.cl 2 Department of Electrical Engineering, University of La Frontera. Casilla 54-D, Temuco, Chile csmarti@ufro.cl Abstract. In this paper, a recursive filter to estimate the offset nonuni- formity for infrared focal plane array imaging systems, using only the scene data, is presented. The proposed algorithm operates frame by frame in a pixel-by-pixel basis and there is not inter-related operations among the detectors. The method assumes that the input irradiance at each detector is a random and uniformly distributed variable in a range that is common to all detectors in the infrared focal plane array. The method is designed to operate in infrared imaging system, which exhibit im- portant offset nonuniformities with slow temporal drift. The ability of the method to compensate for offset nonuniformity is demonstrated by employing several infrared video sequences obtained using an infrared camera. Keywords: Image Sequence Processing, Infrared Focal Plane Arrays, Recursive Filtering. 1 Introduction Infrared (IR) cameras use an IR sensor to digitize the information, and due to its high performance, the most employed integrated technology in IR sensors is the Focal Plane Array (FPA). An IR-FPA is a die composed of a group of photodetectors placed in a focal plane forming a matrix of X × Y pixels, which gives the sensor the ability to collect the IR radiation. Nonuniformity noise in IR imaging sensors, which is due to pixel-to-pixel variation in the detectors’ responses, can considerably degrade the quality of IR images since it results in a fixed-pattern-noise (FPN) that is superimposed on ⋆ This work was partially supported by Grants Milenio ICM P02-049 and by FONDE- CYT 1060894. The authors wish to thank Ernest E. Armstrong (OptiMetrics Inc., USA) and Pierre Potet (CEDIP Infrared Systems, France) for collecting the data, and the United States Air Force Research Laboratory, Ohio, USA. J.F. Mart´ ınez-Trinidad et al. (Eds.): CIARP 2006, LNCS 4225, pp. 464–473, 2006. c  Springer-Verlag Berlin Heidelberg 2006