Abstract: A sensor system includes a sensor and processing means adapted to process the signals from the sensor, and to provide a distance measurement or estimate from the sensor to a metallic object of interest, such as a turbine blade. The sensor, typically an eddy current sensor, provides a signal to which the processing means fits a curve, and parameters including pulse width and height are taken from the fitted curve and used in calculating the distance measurement or estimate. Look-up tables may be used to produce the measurement or estimate. Average values of the parameters may calculated to reduce random noise effects and may be subsequently used to produce correction factors to correct instantaneous measurements.

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: A focal plane detector for imaging objects within a scene and having integral processing means for detecting edges of objects within the scene. The focal plane detector comprises a plurality of detector elements arranged to measure the intensity of the electromagnetic radiation incident thereon and processing means integral to the focal plane detector for combining the intensity measurements so as to indicate the difference in the intensity of the electromagnetic radiation. The focal plane detector is arranged such that the output from the focal plane detector corresponds to edges of objects within the scene. The focal plane detector may be arranged to be sensitive to infrared radiation.

Abstract: The 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 takes 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.

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: 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.

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.