Abstract: Apparatus for scanning a moving object includes a visible waveband sensor 12 oriented to collect a series of images of the object as it passes through a field of view 16. An image processor 14 uses the series of images to form a composite image. The image processor 14 stores image pixel data for a current image and a predecessor image in the series. It uses information in the current image and its predecessor to analyse images and derive likelihood measures indicating probabilities that current image pixels correspond to parts of the object. The image processor 14 estimates motion between the current image and its predecessor from likelihood weighted pixels. It generates the composite image from frames positioned according to respective estimates of object image motion. Image motion may alternatively be detected by a speed sensor such as a Doppler radar 200 sensing object motion directly and providing image timing signals.

Abstract: An illumination source of predominantly non-directional and incoherent millimeter-wave radiation for illuminating an area for passive millimeter-wave imaging comprises a container with at least a partly reflective internal surface and a plurality of exit apertures and a primary source of millimeter-wave radiation for emitting millimeter-wave radiation into the container. The primary source and the container are arranged so that a proportion of the millimeter-wave radiation emitted by the source undergoes reflection within the container before being emitted through the apertures, such that the different paths lengths are at least equal to the coherence length of the radiation. This is facilitated if the bandwidth of the radiation is preferably at least 1 GHz. The container may be a box in which a waveguide is used to couple radiation from the primary source into the box. Alternatively, the container may be formed from a mesh and the plurality of holes is provided by the holes in the mesh.

Abstract: An apparatus for redirecting radiation including a polarization dependent reflector and an optical component able to transform the polarisation of radiation as it passes through the component. Radiation having a first polarisation component impinging upon the reflector from a source is reflected towards a scene area. Radiation not having this polarisation component passes through the reflector. The radiation having the first polarisation is then transmitted towards a scene via the optical component. As the radiation passes via the optical component, reflects back from the scene and passes again via the optical component, the polarisation is changed to state where it can now pass through the polarisation dependent reflector. The apparatus allows a scene to be illuminated as if the illuminator were positioned at the viewpoint of an imaging system, and so aids uniform illumination of the scene.