Abstract: A method for imaging a quantity of gas present in the atmosphere of a selected area. The method comprises the steps of directing background infra-red radiation from the selected area into an interferometer; imaging the infra-red radiation emerging from the interferometer onto at least one infra-red detector: obtaining a plurality of Fouriertransform infra-red spectra in the 8-14 micrometer spectral region, each spectrum coitesponding to infra-red radiation collected from a different portion of the selected area; and displaying in a suitable form an infra-red image, the infra-red image comprising the plurality of infra-red spectra, or quantities derived therefrom. The temperature of the quantity of gas or ambient temperature is measured, the temperature of the background is measured, and the difference between the two measured temperatures is used to derive gas column densities from the infra-red spectra.

Abstract: The presence detector has a passive infrared sensor for detecting the presence of persons in a room, an image sensor operating in the visible spectral range and an electronic evaluator for the evaluation of signals from these sensors. The signal from the passive infrared sensor is used to actuate the image sensor and, if necessary, to switch on the room lighting. Once activated, the image sensor is used to detect both movement and occupancy of a space being monitored. Application of the presence detector for the “on-demand” activation and/or control of conditioning facilities of a room, wherein the signals of both sensors are used for the control of the conditioning facility.

Abstract: A passive ranging optical system is coupled to an active radar system. The passive ranging optical system provides range and rate information to the active radar system. After receiving the range and rate information, the active radar system uses fewer transmission pulses but achieves higher resolution of the range of the target because of improved range gate information.

Abstract: A passive infrared sensor uses a modified lens or mirror to vertically elongate the detection zones in regions close to the sensor. This vertical elongation reduces the signal produced by a small pet, such as a cat, while the greater height of a human intruder produces a larger signal.

Abstract: The invention provides a method and apparatus for guiding a weapon to a target using an optical seeker having dual semi-active laser (SAL) and laser radar (LADAR) modes of operation. The dual mode seeker incorporates a laser light source, an optical package including a quadrant detector for operating in SAL mode and a LADAR receiver for operating in LADAR mode. The seeker further includes a high speed scanning mirror for switching between modes to guide the weapon to the target. The method for guiding a weapon to a target includes receiving radiation from the target and tracking the radiation to guide the weapon; monitoring the detected radiation such that if the radiation falls below a predetermined level, a laser system on-board the weapon continues guiding the weapon by generating a laser beam; reflecting the laser beam off the target so that the reflected laser radiation is received from the target to track the radiation and guide the weapon to the target.

Abstract: The infrared detector contains an entrance window for infrared radiation, an infrared sensor with an evaluation circuit and an anti-masking device having an optical transmitter and an optical receiver for detecting phenomena or optical changes immediately in front of the detector and/or changes in the optical properties of the entrance window. The signals of the anti-masking device are evaluated in two channels, wherein one channel responds to temporally limited phenomena or changes and the other channel responds to temporally stable phenomena or changes. A combined evaluation of the signals in the two channels takes place. In the combined evaluation, the channel processing the signals of the infrared sensor is preferably also included. As a result, the infrared detector acquires an increased immunity to false alarms and a higher sensitivity.

Abstract: A device having an image-providing sensor, hereinafter designated as “image sensor,” operating in the visible and near-infrared range, an thermal image-providing sensor, hereinafter designated as “thermal-image sensor,” operating in the thermal radiation range and having a lower resolution than the image sensor, and an electronic evaluation system. The evaluation system determines whether one or both of the signals generated by the sensors are used for determining whether an alarm condition exists. As a result, the detectability of low-contrast objects is increased, the false alarm rate is reduced, and object classification is made possible.

Abstract: A passive infrared detection system which has a wide angular field of view and a flat or nearly flat front surface. Input optical elements direct and/or focus incident peripheral infrared radiation onto one or more internal Fresnel lens arrays and/or a sensitive area of a detector, including radiation having incident angles of less than about 30°. Because of the absence of protruding elements improved performance and greater functionality can be obtained by employing larger or multiple infrared input windows and/or opto-electronic sections without degrading the aesthetic appearance of the unit.

Abstract: An infrared sensor is formed with a first infrared detecting element for infrared detection disposed in a container through a supporting substrate, and a second infrared detecting element for temperature compensation also disposed in the container to be shielded by the supporting substrate of the first infrared detecting element from incident infrared within the container, while a temperature sensing section of the first infrared detecting element is born in non-contacting state with respect to a supporting part of the substrate for the element, whereby the sensitivity can be remarkably improved with a simpler arrangement while keeping a high precision and inexpensiveness.

Abstract: A system and method of passive ranging for a luminous target which employs a prior knowledge of atmospheric attenuation of spectral frequencies to determine range by comparing the intensities of a frequency component, that is attenuated by propagation through the atmosphere, with a frequency component that is not.

Abstract: Occupancy sensors are presented that include a flat lens for focusing detecting beams into narrower, longer range beams than those of conventional curved lenses. A sensing circuit generates a detecting beam that is substantially perpendicular to the flat lens. The flat lens has a plurality of lens segments that provide long, intermediate, and short range sensing beams. To facilitate positioning of an occupancy sensor, the sensor includes a plurality of indicators that indicate the sensor's long and short range sensing limits. An override timer circuit is provided that upon activation sets the occupancy sensor in occupancy mode for a predetermined time period. A warm-up timer circuit is also provided that upon power-up automatically sets the occupancy sensor in occupancy mode for a predetermined warm-up period. These occupancy sensors are well-suited for environments with long aisles, high ceilings, and high intensity discharge lighting.

Abstract: Condition detecting system has a detecting device (1) including a plurality of pieces of distance sensors arranged at one corner of an observing sector such as a toilet, a judging device for judging the condition of a staying person in the observing sector on the basis of the information from the detecting device (1), a signal transmitting section for transmitting the results of judgment, and a warning device for issuing a warning on the basis of the signal from the signal transmitting section, and the plurality of pieces of distance sensors are set to perform detection in a plurality of different directions by using infrared ray beams.

Abstract: A infra-red bolometer includes an active matrix level, a support level, a pair of posts and an absorption level. The active matrix level includes a substrate having a pair of connecting terminals. The support level includes a pair of bridges, each of the bridges being provided with a conduction line formed on top thereof, wherein one end of the conduction line is electrically connected to the respective connecting terminal. The absorption level includes an absorber with a reflective layer positioned at bottom surface thereof, a serpentine bolometer element surrounded by the absorber and an IR absorber coating formed top of the absorber. Since the reflective layer is attached at the bottom surface of the absorber, which will, in turn, eliminate the need for controlling the vertical distance between the absorption level and the active matrix level.

Abstract: A method of protection and a protective system for protection of an optoelectronic equipment consists in exploiting in a processing unit the data from said equipment and from a laser warning receiver disposed on a common support, in order to detect the time when the impact of a laser illumination enters the field of view of said optoelectronic equipment, estimating the time of coincidence of said impact with the projection of the photosensitive sensor of said optoelectronic equipment in said field of view, and occulting said sensor for a duration at least equal to the dwell time of said laser impact in front of said projection of the sensor. The invention also relates to a protective system fitted with a shutter for implementing said method. Application: Protection of any equipment capable of producing a “cats eye” effect in the presence of at least one illumination in relative motion of fixed with respect to said equipment.

Abstract: Methods and apparatus for generating uniform reference sources for use in calibrating multiple-detector imaging devices. In exemplary embodiments, a plano-plano reference lens is inserted at a non-focusing position in the optics path of a multiple-detector imaging device. The reference lens includes a highly polished side coated with a semi-reflective film and a rough polished side coated with an anti-reflective coating. The smooth polished side causes the detector array to see a reflected image of itself and a portion of the incoming scene energy simultaneously. The energy emitted by the detector array thus mixes with the scene energy to create a detected photon flux level which is dependent upon, but deviates in a controlled manner from, that of the scene energy alone. At the same time, the rough polished side and the thickness of the reference lens blur the detected image to eliminate scene structure and to provide a uniform photon flux level at each detector in the array.

Abstract: A photoconductive detector (3) comprises a single continuous photoconductive strip consisting of two interleaved photoconductive spiral paths (1, 2) separated by much thinner gaps (5, 6). The two spiral paths (1, 2) have the same central point (19). The detector (3) is substantially planar and has the overall shape of roughly a circle (10). A circular band (4) of incident radiation (16) crosses the gaps (5, 6) in a nearly parallel fashion, rather than nearly perpendicularly as in the prior art, lessening unwanted modulations of the detected signal. The terminal (11) to terminal (12) resistance of the detector (3) is increased to the point where, when the photodetector (3) is made of the preferred HgCdTe, simple thermo-electric coolers are sufficient to enable use of the detector (3) as an infrared detector (3) in a heat-seeking missile (17).

Abstract: The present invention concerns a motion sensor for use with a light. The device includes a housing having an outer edge and an interior space in which a plurality of sensors are located. The sensors convert infrared into an electronic signal that is processed to detect motion. A lens located is also used which is located on an outer edge of the housing for directing infrared to the sensors which may be generally arranged in a U-shaped pattern to promote a 270 degree motion detection zone. The ends of the lens are recessed into and held in the interior of the housing a spaced distance from the outer edge of said housing so as to detect motion occurring rearward of the sensors.

Abstract: A system and method are disclosed for optically measuring the temperature of a packaged integrated circuit (IC). A light beam is focused inside the IC package onto a region of the integrated circuit whose temperature is to be measured. The through-substrate reflectivity of the IC, which is a function of temperature and material characteristics (e.g., doping) of the region, determines how much of the incident light is reflected to a photo-detector. The photo-detector measures the intensity of the reflected light and generates a corresponding through-substrate reflectivity signal R. The reflectivity signal R is correlated with transmission curves for that region or materials with similar characteristics and the temperature of the region determined therefrom. Confocal techniques can be applied to substantially reduce measurement signal noise due to light reflected from the IC package which interferes with the light reflected from the IC.

Abstract: Pyroelectric detector systems may be used in vehicles for security applications, such as intrusion detection and anti-theft alarms. The pyroelectric detectors are small in size, highly reliable and consume very low power. They can be physically and electrically integrated with other vehicle components, including rear-view mirror assemblies in automobiles, without incurring additional installation costs. They can also be easily integrated into aircraft cockpits.

Abstract: A staring horizon sensor is mounted on an orbiting satellite has one or more linear infrared detector arrays having the horizon being detected imaged thereon. The arrays are each connected in cyclic repetitive alternating polarity patterns for generating at least two output signals which are offset in phase. The output signals are processed to locate the position of the horizon on the arrays. The repetitive pattern interconnection of the elements in the arrays provide a focal plane data compression which reduces the bandwidth as well as the complexity of the processing electronics. In addition, interconnecting the detective elements in repetitive alternating polarity groups having a spatial frequency greater than the spatial frequency of the thermal variation of the horizon minimize any error due to the earth's thermal variations.

Abstract: A flame detector consisting of a first infrared radiation detector for detecting radiation from combustion of hydrocarbon and other carbon containing compounds in conjunction with a second infrared radiation detector for distinguishing radiation from other sources such as modulated sunlight, reflections, artificial as well as natural hot objects, illuminating light sources, and arc welders. The flame detector uses two electronic circuits following the first infrared detector such that a fire is sensed by either of the two circuits depending on its size, one circuit being optimized for flicker frequencies present in a large fire while the second circuit simultaneously checks for optical signals at flicker frequencies dominant in a smaller fire. The two electronic outputs along with the output of the second infrared detector are digitally processed and analyzed for spectral and temporal characteristics to distinguish the presence of a real fire from that of various false alarm sources.

Abstract: A scanning arrangement comprising means (40) for projecting a two-dimensional optical pattern on a surface (35) of a scanned object and a two-dimensional photodetector (34') is mounted within a hand-held scanning device and outputs scan files of 3D coordinate data of overlapping surface portions of the object. The surface portions defined by these scan files are registered by appropriate rotations and translations in a computer, which are determined either from the outputs of a gyroscope (51) and an accelerometer (50) or by mathematical processing of the surface portions e.g. involving detection and location of common features.

Abstract: A non-volatile electron beam-addressed light-valve produces a flickerless, all-at-once visible light output which is then converted into a flickerless projected infrared scene suitable for testing an infrared imaging seeker.

Abstract: A rosette or co-rotating vector scanning seeker detector array providing improved data rate and scanned field coverage. Several discrete detector elements are formed in an array on the detector surface in a coplanar arrangement, each of the detector elements providing target information when the scan sweeps across it. The array may be in the form of circular spots arranged around a central circular detector element. In an alternative embodiment, the central detector element is omitted and the peripheral detector elements are arranged sufficiently close together to preclude the likelihood of a target path passing between adjacent detector elements without being detected. Detector elements in a single array may be of different sizes and shapes.

Abstract: The digital sampler circuit processes an output signal from a high gain analog amplifier having as input an infrared motion detector output signal and a negative low pass filtered feedback signal. The amplifier output signal is a substantially square pulse signal having an irregular frequency and duty cycle and has an average duty cycle indicative of a DC level and a slow change in the DC level of the detector output signal. The sampler circuit includes a detector circuit for detecting the amplifier output signal and discriminating at regular intervals a high/low state of the output signal, and generates a high/low feedback signal corresponding to the high/low state of the output signal detected. The high/low state of the output signal is analyzed over a predetermined number of the intervals to obtain a ratio value for producing an output digital signal sample value. The digital sample value is a measure of the DC level and the change in the DC level of the detector output signal.

Abstract: A thermally differentiable pattern such as hot melt adhesive is monitored in a production line system. An electrical output from a thermopile radiation sensor is applied to a detection circuit which processes the sensor electrical output to perform an inverse to the sensor transfer function and to perform a differentiation which provides a pulsed output at rising and falling edges of the sensor signal. Comparators provide respective output pulse signals representing the respective rising and falling edges. An adjustable amplifier in the circuit adjusts pulse threshold relative to sensed radiation.

Abstract: An intrusion detection assembly including an intrusion detector including an inner housing, a detector disposed within the inner housing and a lens for focusing light from outside the inner housing onto the detector, and an outer housing which is generally sealed from the outside and defines a window which is generally transparent to light which is detected by the detector, wherein the intrusion detector is spaced from the window so as to define a region of high sensitivity between the lens and the window which is sealed from the outside environment.

Abstract: A temperature and passive infrared sensor module in which a temperature sensor is mounted so as to not be adversely affected by heat generating electrical components of the sensor module. One embodiment comprises a wallswitch-mounted unit which is designed to be mounted in a wallswitch electrical outlet box with a semi-cylindrical front of the sensor projecting forwardly therefrom. A top section of the projecting semi-cylindrical front has a front curved window, behind which a passive infrared sensor and an ambient light sensor are positioned. A bottom section of the projecting semi-cylindrical front is formed by a removable clip-in door which is provided with air flow vents in a bottom surface and also in projecting front and side surfaces thereof to provide a circulating air flow around a temperature sensor.

Abstract: A movement pattern recognizing apparatus has a movement signal detection device including a sensor for detecting a mobile body in a detection region and for providing a movement signal indicating the position of the mobile body. The signal changes as time elapses. The apparatus further has a movement pattern storage device for storing data about previous movement patterns which were realized when a mobile body moved in the detection region, and a movement pattern selection device for selecting data about the movement pattern from the movement pattern storage device based upon the movement signal detected by the movement signal detection device.

Abstract: A process and system for flame detection includes a microprocessor-controlled detector with at least three sensors. A wide band infrared sensor is used as the primary detector, with near band and visible band sensors serving to detect false-alarm energy from nonfire sources. Digital signal processing is used to analyze sensed data and discriminate against false alarms. A multistage alarm system can be provided, which is selectively triggered by the microprocessor. Spectral recording and analysis of prefire data is provided for. The detector can be housed in an enclosed, sealed, removable, plastic horsing that may include an integral plastic window lens.

Abstract: A boresight mechanism 10 incorporating internal boresight target generator 28 to generate a boresight target signal for properly aligning first and second sensors 22, 24. Beam splitter 52 and corner reflector 60 are positioned along optical path 100 such that sensor 22 and sensor 24 can view either the boresight target signal or a target signal without requiring optical elements to be slued into and out of position to provide a clear line of sight.

Abstract: The present invention provides a method for distinguishing a boundary of an object, and the object itself, from its background. In the method electromagnetic radiation is detected from at least one field of view substantially spanning the boundary of the object and background adjacent to the boundary and superimposed or overlaid as images onto a detector. The method includes correlating spatial transitions in intensity of the overlaid images on the detector with a boundary of the object. When used for determining the attitude of a satellite with respect to the earth, the detector is a thermal infrared detector thereby providing a sharp contrast between the thermal emission of the earth and cold space. The invention provides a simple, effective method and device for determining satellite orientation and/or attitude with respect to a thermal infrared-emitting target body.

Abstract: An infrared collector employs a concentrator formed of a plurality of spatially related gradient-indexed (GRIN) lenses and a photodetector, interconnected by optical fibers. Since the GRIN lenses are arranged on a hemispherical shell, the concentrator is relatively insensitive to the direction of the incoming infrared radiation. Optical fibers are used to connect the GRIN lenses to a photodetector, whereby assembly is simplified. The infrared detector in the collector of the present invention has a size that is significantly smaller than those used in conventional collectors. The concentrator has high optical gain, and therefore, is particularly well adapted for use in low-power portable systems. The arrangement is useful as a node in an infrared data network.

Abstract: A multi-lens system provides a plurality of sensitive areas of even size over a wide panoramic field of view and reduces an exposure height of the system above an installation plane, yet assuring successful motion detection. The system has a dome-shaped shell with a plurality of convex lenses for collecting infrared radiation from the panoramic field of view to an optical detector positioned in a focal region. The lenses are distributed over a wide solid angular range to give the discrete sensitive areas. The focal region is offset towards a vertex of the shell from a point where optical axes of the outermost lenses at a maximum solid angle about the center axis intersect with each other. Thus, the outer lens at a greater angular disposition has a greater distance to the detector so that it could define its own sensitive area closer in size to the adjacent sensitive area defined by the adjacent lens at a less angular disposition, enabling to equalizing the discrete sensitive areas.

Abstract: A catoptric optical system enhances the ability of a radiation sensor to detect motion of a radiant source within a region of a three-dimensional space without need for a polyethylene lens array. A preferred embodiment of the system includes first and second pairs of spaced-apart concave reflector elements arranged to form a chamber having a radiation reflective interior with a rectangular opening at each of input and output ends. The reflective elements of each of the first and second pairs are positioned in opposed relationship and separated by respective first and second distances. A two-element radiation sensor having a top surface is positioned proximal to the output end of the chamber.

Abstract: A missile for detecting and combatting enemy helicopters has an infrared homing head with an infrared lens and infrared sensor that will emit electrical signals, depending on incident infrared radiation, and the sensor is designed as a two-dimensional detector matrix consisting of a number of punctiform detector cells arranged essentially in the focal plane of the infrared lens. The homing head includes an arrangement for acquiring a target and determining the type of target from the target information by individually scanning each of the detector cells quickly one after another by evaluating the amplitude and frequency of the electrical signals. The determination includes determining the relative position of the target to the optical axis of the homing head and the homing head will then steer the missile to hit the target.

Abstract: Two pairs of pyroelectric devices are each mounted on a cone-shaped substrate to precisely control their alignment. Each cone-shaped substrate is a part of a sensor module which also supports an attenuator, along with a transistor and a resistor chip associated with each pyroelectric device of the pair. The sensor module is provided with a silicon filter through which infrared radiation is transmitted to the pair of pyroelectric devices. Each module is mounted in an inner space formed by two hemispherical lenses which serve to direct light to the module. Two such hemispherical lens-sensor modules are provided in a precise optical arrangement designed to operate in conjunction with associated circuitry in order to detect infrared radiation from any of six distinguishable zones. Applications of such a device include for example cameras and air conditioning systems.

Abstract: An aiming device (or method) which monitors rotational and angular displacement changes with high precision. The detected changes in rotation and/or angular displacement are then used in various operations depending on the implementation. The invention is useful for many different implementations, including a pointing device, a remote control device, and a shooting practice system. Regardless of implementation, the invention utilizes one or more emitters which emit modulated energy signals, and a detector which detects the emitted energy signals. The detected energy signals are processed by a processing unit to determine a point of aim (angular displacement) and a rotation of a detector with respect to the one or more emitters. As a remote control device, the invention enables a user to invoke actions by pointing and rotation of the remote control device. As a shooting practice system, the invention predicts shot placement on a target with high accuracy, while supporting both "live" fire and "dry" fire.

Abstract: A personal infrared beacon unit capable of being worn as an adornment of clothing, incorporated into a part of a person's attire, or embodied within a personal pager, a cellular phone or a 2-way data device. The beacon unit may be in communication with an established network and may be activated externally by a locator signal, or internally by activation of an emergency button. Upon activation, the beacon unit emits coded timed infrared bursts in coherent beams, and when the beams are detected, they may be decoded visually or with a decoding device to provide the identity and location of the user.

Abstract: A dual element PIR detector for a security system uses a series of beams in selected areas to limit the amount of radiation received from small domestic pets. A series of alternating beams define dead zones and the beams and dead zones provide size discrimination where a small domestic cat or other small pet does not have sufficient size to cause IR responses in two sensors sufficient to cause an alarm condition.

Abstract: A multiple detector array is positioned in a satellite orbiting the earth for determining the attitude of the satellite with respect to the earth by detecting the earth's horizon. The multiple array of spaced detectors are mounted on a horizon sensor with a space detector viewing space, a horizon detector, with a field of view straddling the horizon and outer space space, a detector viewing the earth, and a gradient detector viewing the earth. Individual signals from these detectors are amplified and processed such that any gradients between the two earth viewing detectors are used to provide radiance compensation to correct for radiance errors in sensing the true position of the horizon.

Abstract: A motion sensor has a pyroelectric detector, a Fresnel lens array, a reducing lens, and a housing. The detector has two elements located side-by-side and the lens array has a plurality of lenslets which are integrally formed. The reducing lens demagnifies the elements. The reducing lens has grooves which run in parallel directions and face toward the elements. The lens array illuminates the detector by focusing infrared light through the reducing lens and onto the elements. The reducing lens makes the elements appear smaller and closer together. The reduced image of the detector allows the lenslets to be spaced more closely than prior art lenslets, thereby making the angular separation less than the angular separation of prior art sensors. Alternatively, the detector housing may be made smaller while maintaining the same angular separation of prior art sensors. If an object moves between two zones, the sensor detects the movement and triggers an alarm, turns on a light, or initiates some other process.

Abstract: A simplified analog passive infrared motion detection circuit operates using only four operational amplifiers. A first amplifier is used as part of a bandpass amplifier circuit, a second is used in an inverter circuit, a third is used in an integrator circuit and a fourth is used in a threshold comparator circuit for generating an alarm output signal. The circuit is built using a single quad op amp IC package and is economical to manufacture. The third op amp can alternatively be used as a passive infrared sensor preamplifier and a transistor can be used in the integrator circuit, so that a regulated power supply for the circuit is not needed.

Abstract: A thermal object detecting method and apparatus. According to the method and apparatus, a thermal image of a measuring space is obtained by a two-dimensional thermal image detecting device. Then, position information of an object in the measuring space is obtained by an object distance detecting device, which determines a distance between the apparatus and the object. The output of the two-dimensional thermal image detecting device can be corrected using the distance data from the object distance detecting device.

Abstract: An arrangement for detecting targets with an infrared sensor. The number of false alarms can be reduced by comparing image matrices generated by a detector in one revolution on the basis of pre-alarms generated in the image matrices by point target extractors. Between the matrices generated in succession, differences are introduced by means of a different spectral response, polarization section and parallax.

Abstract: A composite Fresnel lens useful in an infrared passive detection system includes an array of Fresnel lens segments having a given vertical centerline and a curvature of a given radius. The Fresnel lens segments fall in first and second groups. Each Fresnel lens segment in the first group has a long detection range and a width less than one-third of the diameter of an original whole Fresnel lens from which the segment was taken. Also, each lens segment of the first group has a geometrical center located horizontally from the vertical centerline of the array along the curvature of the array through a circumferential distance less than one-fourth of the radius of curvature of the array. Each Fresnel lens segment in the second group has a short detection range less than the long detection range by a predetermined amount and a width less than one-third of the diameter of an original whole Fresnel lens from which the segment was taken.

Abstract: In a reflection type angle of view transforming optical apparatus for transforming an angle of view in an image apparatus and so forth, sufficient strength can be provided and process is facilitated by using reflecting mirrors in a wide angle optical system. The reflection type angle of view transforming optical apparatus includes a primary mirror 8 having a reflecting surface provided in an axisymmetric form to reflect incident light 12 as primary reflected light 13, a secondary mirror 10 having a reflecting surface provided in an axisymmetric form about the same axis of rotational symmetry 9 as that of the primary mirror 8, opposed to the primary mirror 8 so as to reflect the primary reflected light 13 and to get secondary reflected light 14 for focusing on a view point, and a transparent case 11 to support the primary mirror 8 and the secondary mirror 10, and transmit the incident light 12.

Abstract: In an infra-red surveillance system, a digital memory (1) has a storage location for each of a number of zones, defined by azimuth and elevation co-ordinates, the zones together covering 360.degree. in azimuth and 20.degree., for example, in elevation. In each location there is stored a data word built up from the responses on a zone in successive scans. Each word can be read into a decoder (5) which selects an appropriate video display level in the form of a two-bit word which is then stored in a buffer store (6). A buffer store data controls the display on a cathode ray tube (2). A manually controlled cursor circuit (8) generates a cursor address which results in a cursor display at the corresponding position on the cathode ray tube. The display is in the form of four strips, one above the other, each representing a quadrant of azimuth.

Abstract: An infrared sensing device includes a condensing lens for gathering an infrared ray from a human body, a guide unit for dividing a room to be monitored into a plurality of lateral and vertical zones and for guiding the infrared ray to a part of an infrared sensor unit corresponding to its direction, a housing for enclosing the condensing lens and guide unit to preclude dispersion of the incident infrared ray, an infrared sensor unit for sensing an infrared ray of a certain zone or infrared rays of a plurality of zones guided by the guide unit and housing, and a signal processing unit for amplifying an output signal of the infrared sensor unit, and for converting the applied signal into a digital signal and analyzing the digital signal.

Abstract: A microstructure design for high IR sensitivity having a two level infrared bolometer microstructure, the lower level having a reflective metal film surface such as Pt, Au, or Al to reflect IR penetrating to that level, the upper level being separated from the lower level by an air gap of about 1-2 microns which allows the reflected IR to interfere with the incident IR and increase the sensitivity to a higher level.