VIDEO SCAN CONVERSION

A system for converting video signals from a scanner from, for example, an air surveillance system comprising an interface (2) which applies incoming video signals directly to a bulk store (5) and to a scan converter (4). The interface can also apply signals from the bulk store to the scan converter. The signals received from the bulk store can be processed differently from those received directly by the scan converter. This system allows maximum possible resolution of the image to be maintained for zoom in and for roaming.