1. A system for combining multi-spectral images of a scene, the system comprising: a channel for transmitting a scene image in a first spectral band; a separate second detector for sensing the scene in a second spectral band, the second detector having an image output representative of the scene; a transparent display for receiving the image output of the second detector, and displaying a displayed image from the second spectral band; and the transparent display being positioned in an output path of the transmitted scene in the first spectral band.