Abstract: A sensor having a detector array is provided with means for determining whether the normal field of view of the sensor has been obscured. The image output from the detector array is compared by a processor to an image of the normal filed of view, previously acquired and stored in a memory. Where there are significant differences between the images the processor activates an alarm. The location of high spatial frequency detail in the image may be compared and the absence of such detail used to give an indication that the sensor may be masked.

Abstract: The invention relates to a device and method for communicating with a thermal detector module and an appropriate thermal detector for a use with such a control device. The device for communicating with a thermal detector module comprises a means for providing a collimated beam of thermal infrared radiation and means for modulating the intensity of the collimated beam of thermal infrared radiation. The intensity modulated thermal infrared beam, when directed on to the thermal detector module from a position within the module's field of view, is suitable for triggering a response from the thermal detector module. The intensity modulated thermal infrared beam may also be encoded with a digital signal to control the function of the thermal detector.

Abstract: A method of hermetically packaging an electronic device (8), in an enclosure (2) comprising mutually inter-engageable first and second housing members (4, 6), comprising the steps of securing the electronic device (8) to the first housing member (4), engaging the first (4) and second (6) housing members such that an hermetic seal is provided there between, wherein the engagement step is performed in a controlled atmosphere. The hermetic seal may be provided by an interference fit between the first (4) and second (6) housing members or via sealing means (16) interposed between the housing members (4, 6). The second housing member (6) may comprise an optical element (20), for example a window or lens. The packaging method is particularly applicable to packaging thermal detectors, for example microbolometer arrays.

Abstract: An Array of detectors can be configured to be read as separate detectors, or to be connected into larger groups, e.g. groups of four (a 2×2 array). This allows the formation of a relatively high definition image, and a much faster formation of a lower resolution image. This may be used with in an automobile to control deployment of safety airbags in accordance with a drivers position relative to the airbags. Preferably the array is a 64×64 array of thermal detectors.

Abstract: A focal plane detector adapted to be calibrated using an image of part of the human body. Further, a method of calibrating a focal plane detector having a plurality of detector elements, comprising the steps of presenting a first and a second image to the focal plane detector array, measuring the output from each detector during each first and second image, analysing the outputs and compensating for errors in the output of each detector element such that the outputs from the detector elements are substantially equal when illuminated with electromagnetic radiation of a given intensity. The first and second images have substantially no discernible features therein, and one of the first and second images comprises an image of part of the human body. The apparatus and method are particularly applicable to focal plane detectors sensitive to infrared radiation.