APS fixed pattern noise modelling and compensation

In this paper we describe different procedures to compensate the fixed pattern noise (FPN). These procedures have been developed and tested for a camera designed by us, which is based on a CMOS active pixel sensor (APS). In this kind of sensors, the FPN mainly depends on the noise coming from the column selection electronics. In this sense, we suggest and assess three different methods for FPN compensation: using a simple model taking into account this dependency, using an external test signal routed through the image chain and finally using a region of the sensor which is not illuminated. The first two procedures are of special interest for camera systems lacking a shutter or a not illuminated region in the sensor. The last one is more similar to the typical approach, but requires using a larger sensor only to have some covered light sensitive area.