In this work, a sensor model has been outlined mainly as an addition to synthetic imagery generation tools such as CAMEO-SIM and McCavity. The sensor model is based on defining and identifying physical parameters and models for describing optics, detector matrix, noise, motion and atmospherics among other imaging specifics. A short review of MTF is given as well as a noise model for semiconductor pixel based sensors, especially CCD focal plane arrays. A discussion of FOI specific experimental sensor systems is given as well as some critical parameters for model implementation of these systems. Two sensor modelling examples are described as well as some selected results.