Sensor apparatus

Abstract

The invention provides a sensor apparatus ( ) with compensated signal processing for generating a sensor signal corresponding to a filtered image of a scene. The apparatus ( ) incorporates a multielement array ( ) for providing at each element ( ) first and second signals in response to first and second scene images projected onto it and a lens assembly ( ) for projecting the images onto the array ( ). Each element ( ) is connected to an associated circuit ( ). Each circuit ( ) performs a subtraction of the first and second signals of its associated element from one another to provide a difference signal and supply this signal for use in generating the sensor signal. Each circuit ( ) incorporates a transistor (T ) for injecting charge to compensate at least partially for subtraction accuracy degrading parasitic charge injection occurring within the circuit ( ) when the apparatus ( ) switches between projecting the first image and the second image onto the array ( ).