OSIS (Optronic System Imaging Simulator) is an imaging simulation tool developed by Fraunhofer IOSB. It generates virtual camera imagery based on real or artificial scenes represented by input images. In doing so, the pristine input image is degraded by various effects caused by atmospheric attenuation, optics, detector footprint, sampling, fixed pattern and temporal noise, digital signal processing, and display. OSIS incorporates the imager specification provided by TRM4. For further information please visit the OSIS web page.

In ECOMOS II, the functionality of OSIS is used internally to produce virtual camera imagery of TOD test patterns required by the image-based TOD approach.