Qinetiq Limited

Rupert Nicholas Anderton

Peter Russell Coward

Alan H Lettington

Roger Appleby

Paul Antony Manning

Richard George Humphreys

Kevin James Palmer

Sean Price

Kevin Palmer

The present invention discloses a detection device for discriminating between different materials, and a method for doing so. The device comprises an optical system having at least one optical focussing element and a receiving element. The receiving element is sensitive to electromagnetic radiation, typically in the millimeter wave band, and the optical system being arranged to focus incident energy from a scene onto the receiving element. The optical system comprises a prism element having a first surface and a second surface, the first surface being opposite the second surface. At least a portion of the first surface is positioned at an angle &#x3b8; to the second surface. The angle &#x3b8; varies between a minimum at a first position on the first surface and a maximum at a second position on the first surface.

Detection device

A radiation detection apparatus comprises a radiation detector and a lens arrangement. The lens arrangement comprises a polarising element and an optical corrector. The optical corrector is preferably located between the polarising element and the radiation detector and has at least one surface designed to correct optical aberrations present in the lens arrangement. The optical corrector may be arranged to provide a mechanical support to the polarising element. The optical corrector is arranged to increase a diffraction limited acceptance angle of the apparatus.

Radiation detection apparatus

A scanning imaging apparatus comprises an optical system including a curved polariser/reflector, a rotatable reflector, a polarisation twisting plate, and a receiver array, wherein a convex reflective element is incorporated in the optical path that acts as a sub-reflector that increases the optical system focal length. It has been found that an increase to the optical focal length in this manner gives a greater 3 dB spot size at the image plane, thus easing design constraints on the receiver array packing density, whilst maintaining a given spatial sampling interval. An additional benefit is that radiation from differing scan locations diverges as it approaches the image plane, which provides more volume in which to position receiver electronics. Focussing of the optical system may be achieved by movement of the sub-reflector.

Scanning imaging apparatus

A detection device that can be used for detecting objects behind clothing etc including a dielectric lens and a receive element sensitive to millimetre wave radiation. Prior art systems produce an image of a scene usually using scanning optics. This can be large and expensive. The present invention instead take spot readings from different parts of a scene without building up an image. The spot readings are processed, and an indication given to a user if certain characteristics of the readings are observed. Typical characteristics used are the differences in absolute received power level, and the power level at different polarisations. Such characteristics are typically present is an object of interest is in the scene. Also disclosed are various methods of altering the received beam to get readings from different areas from the scene, such as changing the beam width, or beam angle.

Millimetre-wave detection device for discriminating between different materials

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. The apparatus is particularly suited to mm-wave systems, wherein the reflector may comprise a parallel wire grid polarizer, and the optical component may comprise a quarter-wave plate.

Apparatus for redirecting radiation

A system for imaging the contents of containers includes an imager arranged to receive millimetre wave radiation from a reception volume through a receive antenna wherein, in use, the container is moving relative to the receive antenna, the reception volume is positioned such that the relative movement causes the reception volume to move through the container; data from the antenna is recorded as the reception volume moves through the container, and an image of the contents of the container is built up from the recorded data. The system is particularly suitable for imaging containers mounted on vehicles. The imager may advantageously be mounted in a portal, allowing convenient and controllable relative positioning of the container, and allowing the relative speed to be controlled or measured easily. The invention allows 3D or pseudo 3D images to be produced to aid identification of container contents. The invention also includes a method for imaging.

Imaging system and method

A steerable antenna or scanner assembly ( ) is connected to signal process means ( ). A housing ( ) surrounds a focusing antenna ( ) which is stationary relative to the housing ( ), a polarisation rotator ( ), a steerable reflector ( ) angularly movable about a pivot axis ( ), and a detector ( ). Incoming radiation passes through the focusing antenna ( ), has its polarization altered as it passes through rotator ( ), reflects off reflector ( ), Passes through rotator ( ) again, encounters the antenna ( ) again and this time reflects off it to focus down, passes through rotator ( ) again, encounters the steerable reflector ( ) again and this time passes through it to reach the detector ( ). Moving the reflector ( ) angularly steers the directional sensitivity of the assembly ( ).

Steerable transponders

Scanning apparatus which may be used in a real-time passive millimeter wavelength imaging system or in other radiometry systems. The apparatus scans input radiation from a scene and output radiation is transmitted to a receiver system, for example a millimeter wave imaging camera or a radar receiver. The apparatus comprises a rotatable reflective plate having an axis of rotation passing through the centre of its surface and a lens arrangement for selectively transmitting and focusing radiation having a particular direction of polarisation. The apparatus may also comprise a feed horn array comprising a plurality of feed horns, the feed horns forming part of a spherical surface having a radius of curvature substantially equal to R/2 and being concentric with the third substantially spherical polarising element. The apparatus may further comprise a detector array comprising a plurality of detector elements. The detector array may form part of a millimeter wave imaging camera.

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Malvern, United Kingdom

Rupert Nicholas Anderton