Abstract: Apparatus for measuring the temperature distribution along the inside walls of narrow, shaft-shaped spaces such as heating flues of coking and similar ovens using a radiation pyrometer with an evaluating arrangement, whereby a radiation optical system is disposed at one of the ends of the space and contains a mirror tiltable about an axis, for optical coverage of the entire length of the space and forwarding of the detected radiation into the path of rays to be evaluated, as well as a positioning arrangement for tilting the mirror over the area to be optically covered. Therewith a fixed mirror is arranged after the tilting mirror and the path of rays to be evaluated is focused to the end of a photoconductor, which, in a transportable and coolable measuring lance, is directed to an evaluating arrangement. The measuring lance can be coarsely and finely positioned by means of a carriage arrangement.

Abstract: A scanning mechanism for a fast framing thermal imaging system such as a FLIR is disclosed. The scanning mechanism comprises two prisms which are canted with respect to one another and positioned in front of the final image forming lens of the FLIR. The two prisms are precisely counter-rotated with respect to one another by a drive train assembly and motor means. An annular timing disc is positioned about one of the prisms to enable an optically sensitive transducer to sense the rotational position of the prisms. The counter-rotating prisms function to enable the detector array of the FLIR to dissect the thermal image in a 2:1 interlacing technique.

Abstract: A passive infrared intrusion detector is provided with a lens having selectable patterns of sensitivity. The lens unit can be mounted to the detector in two orientations to provide two different patterns of sensitivity.

Abstract: An electronic logic circuit utilized in conjunction with a scanning infrared detector to generate pulses which accurately indicate the precise location of the center of a preselected astronomical radiant body, such as the earth, notwithstanding a wide scanning frequency range with unknown initial value, and capable of rejecting undesirable input signals, is disclosed. The pulses are initially generated so as to conform the frequency of a generated signal to that of the signal applied from the infrared detector, thereby correcting the large initial signal frequency error. Both the conditions of an initially high and low frequency of oscillation of the generated signal relative to the applied signal are corrected. After such frequency correction has been rendered, signal phase correction is accomplished so as to negate the difference between the exact center of the signal applied from the infrared sensor and the trailing edge of the generated signal.

Abstract: The invention is for discriminating between the fire or explosion of an ammunition round and the fire or explosion which may then take place in the object struck by the round, and for initiating suppression of the latter fire or explosion only. Short wavelength radiation detectors feed a ratio detector which produces a logical output dependent on whether or not the color temperature of an event being monitored is above or below a fixed value. If the event is an exploding round then this will take the color temperature above this fixed value. A threshold unit and a rate of rise unit produce logical outputs dependent on whether the magnitude and rate of rise of the output of one of these two detectors are above or below fixed values. An infra-red detector detects radiation at a wavelength characteristic of a fire in the object; its output rises relatively slowly.

Abstract: A pyrodetector is disclosed which has a sharply limited directional range of detection sensitivity for the detection of a body entering into its directional range at a distance from the detector, the body having a temperature which is different from that of its environment. A concave mirror for focusing thermal radiation emanating from the body is provided and a pyroelectric sensor positioned at a focus of the mirror is also provided and formed as a flat body consisting of an electrically non-conductive material and with a pair of electrodes. A cover transmissive to the incident thermal radiation is provided for protecting the sensor element against damage and air drafts. At least one further sensor element similar to the first sensor element and with essentially the same heating time constant is also provided and arranged adjacent to the first sensor element but beyond the mirror focus.

Abstract: An image forming scanning mechanism without obturation in its optical path comprises first and second reflectors that are pivotally actuated about respective orthogonal axes. The scanning reflectors are positioned so that radiant energy in a first optical path from an object field impinges upon a vertical-scan reflector where it is directed to a horizontal-scan reflector and whereupon it is directed back onto the vertical-scan reflector from whence it is reflected along a second optical path in a different plane from the first optical path. The pivotal axes of the vertical-scan reflector and the horizontal-scan reflector are perpendicular to path of radiant energy reflected therefrom. A detector is positioned to receive radiant energy from elemental areas of an object field. The orthogonal disposition of the first and second pivotal axes provides a distortion free image signal from the detector that is comparable with the x-y scan pattern of conventional television display circuits.

Abstract: As CCD circuit for restoring to a common DC level, data received from a plurality of detector channels of a scanned array so as to overcome the effect of variations in detector parameters and other non-uniformities in the circuit. The DC correction value is established during retrace time by storing a representative time integrated data charge packet when energy from a cold reference surface is being applied to the detectors. During the scan time of the field of view by the detectors the representative charge packet is utilized to provide a DC restoration or correction charge to each data charge packet received from the detectors. The system thus standardizes to a common DC level, the output data from a plurality of channels.

Abstract: A family of two axis horizon sensors using the same basic scan technique is provided which achieves a relatively wide altitude range with a minimum of moving parts for performing vehicle attitude control and guidance. The horizon sensor for indicating the orientation of a space vehicle senses a line of discontinuity in optical radiation between a reference planet and outer space in at least two planes using a single sensor which includes a single detector means for detecting the optical radiation. The detector is scanned across the line of discontinuity in at least two planes. The scanner includes a rotary element driven by a single motor having at least two stationary reflecting elements positioned therearound. A phase reference signal generator is coupled to the motor and driven in synchronism therewith for generating at least two reference signals at predetermined points in the scan.

Abstract: Scanning radiation source detecting apparatus, comprising means for deriving a general response signal in response to radiation from any part of a field of view, and a central response signal in response to radiation from a central part of the field of view, with means for producing audio signals of a frequency dependent on the magnitude of the central response signal. The apparatus may produce a constant frequency signal in response to the general response signal, and the central response signal may be derived from the general response by a gate circuit controlled by a scanning mirror mechanism. The gate circuit may be connected to a voltage controlled oscillator by a sample-and-hold circuit or, by an integrating circuit. Alternatively the apparatus may comprise a light emitting diode energized by a radiation detector, an optical system arranged to form an image of the diode and two separate detectors placed in the optical system to form the general response and central response signals.

Abstract: The measurement of the temperature of a body such as a wire, bar or tube, or a metal sheet, is effected in relation to a black background by providing either a swinging mirror or two flat mirrors and either a concave spherical mirror associated with the flat swinging mirror, or two concave spherical mirrors associated with the two flat mirrors, as well as an infrared radiation detector whose sensitive element receives alternately and successively, after reflection by the flat mirror(s) and collection by the spherical mirror(s), on the one hand, the infrared radiation of the wire and of the black background which surrounds it and, on the other hand, of the black background alone.

Abstract: A technique for detecting very small quantities of particular materials by absorption of visible, ultraviolet or infrared light from a laser source is disclosed. The technique takes advantage of the thermal lens effect, i.e., a thermally induced alteration of the index of refraction, which occurs whenever a laser beam is passed through an absorbing medium, especially fluids. A converging beam derived from a coherent, collimated beam, e.g., a laser beam in the infrared, visible, or ultraviolet light range, is passed through a reference cell. The converging beam is slightly modified by a change in the index of refraction due to the thermal lens effect occurring within the reference cell. The modified beam is passed through a sample cell containing the identical medium as that in said reference cell with an additional material therein sought to be identified.

Abstract: The technique of attenuated total reflection (ATR) analysis can be applied to the deposit on a filter, enabling crystalline silica deposited on a glass fibre filter to be determined, which is impossible using transmission IR spectrophotometry. An improved ATR apparatus has pressure means to bring a sample such as that collected on a filter into contact with the prism and is arranged such that the face of the prism defines the area of the sample for analysis.

Abstract: A radiation scanning system comprises a detector 12 which forms part of an assembly 11 maintained at a temperature substantially below ambient, an imaging means 18 for forming an image of radiation from a field of view, a scan member 15 and a relay lens 14 arranged to scan an image of the detector 12 across the radiation image and an arrangement for applying a characteristic radiation feature to the detector 12 at a selected part of the detector image locus 19 lying outside the normal scanned field of the system comprises a mirror 20 arranged to reflect radiation from the cooled assembly 11 onto the detector 12.

Abstract: An optical system for scanning thermographic pictures comprises a rotating polygonal cylinder for line scanning in one coordinate direction. The polygonal cylinder is subdivided into an inner stationary solid cylindrical portion and a ring surrounding the cylindrical portion. The ring is on its outer side provided with the polygonal faces and rotates around the cylindrical portion. The cylindrical portion has a single curved face extending substantially perpendicular to the optical axis. The inner wall of the ring and the curved face define between them a cylindrical air lens element. The shape of the curved face is computed in accordance with the image distortions of the optical system so that the air lens compensates for the image distortions.

Abstract: An optical arrangement for use with an infrared detector characterized by a concave mirror surrounding the infrared detector, a body having a plane reflecting surface extending perpendicular to the axis of the detector, which surface faces the detector and the conical concave mirror, and having a conical reflecting surface extending from the plane surface, and at least one planar directional mirror pivotably mounted for reflecting infrared radiation at the conical reflecting surface. The arrangement can be used to monitor a space and if used with a second arrangement, whose directional mirrors are arranged to provide new sensing curtains adjacent the curtains of the first detector, the arrangement can determine the direction of movement of the object passing through the space.

Abstract: An optical arrangement for a passive infrared motion detector which has an infrared detector unit and a system for directing infrared radiation from at least two separate directions to be monitored onto the detector unit characterized by the system including a single focusing device and separate, flat reflecting surfaces or directing mirrors, which are arranged with at least one flat reflecting surface associated with each direction to be monitored to reflect a beam or solid angle of radiation from the direction onto the single focusing device which device will focus the radiation along a folded beam path to the detector unit.

Abstract: An I. R. target detection arrangement having a high-inertia line scan and a low inertia frame scan. The line scan is performed by scanning a line of I. R. detectors broadside over a section of the target scene, storing the detector outputs for each point on each line, repeating the line scan and output storage a number of times without change of frame scan, accumulating the outputs for each point obtained in repeated scans, and stepping the frame scan to the next section. A greater signal/noise ratio is thus obtained. Upon detecting a target, the frame scan is switched to a continuous mode and the field of view is narrowed and magnification increased.In each section interlacing may be obtained by stepping the frame scan half the line pitch and repeating the line scan process before proceeding to the next section.

Abstract: The invention contemplates a heat-detection system with optical, scanner and display components for periodic mechanical heat-scanning of a given field and for so correcting the phase of electrical signals developed in the course of scanning as to enable development of a visible display of the field without phase-shift errors which are attributable to mechanical motion of the scanner.

Abstract: An infrared analyzer is described which analyzes constituents of a sample. The sample and/or reference signals are synchronously averaged to provide unisonous sample and reference values. This processing eliminates drift and signal noise from the measurements, thus providing a more sensitive and accurate characterization of the constituents of the sample.

Abstract: Disclosed is an optical system for use in a multispectral scanner of the type used in video imaging devices. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and reflects visible and near infrared energy. The long wavelength beam is filtered and focused on an infrared detector positioned in a cryogenic environment. The short wavelength beam is dispersed by a pair of prisms, then projected on an array of detectors also mounted in a cryogenic environment and oriented at an angle relative to the optical path of the dispersed short wavelength beam.

Abstract: A detector for a single beam pneumatic infrared analyzer having two light receivers, a front receiver and a rear receiver positioned in series in the path of infrared light rays coming from a sample cell and each of which has a gas enclosed therein and used for measuring the concentration of a sample flowing through the sample cell by comparing the different absorption spectra of the infrared rays hitting the two receivers, and a screening device in front of the front light receiver for screening out the infrared rays in only the peripheral portions of the light, along the light path entering the front receiver.

Abstract: A radiation scanning system comprises a detector, a transfer lens forming a real image of the detector, a rotary scanning means interposed between the transfer lens and the detector image in such a way that as the rotary scanning means is rotated the detector image moves in a circular locus, a concave substantially-spherical mirror concentrically disposed with respect to the detector locus, said locus being at the focal surface of the mirror so that for different rotational positions of the rotary scanning means differently directed parallel bundles of rays emanate from the mirror all intersecting at a pupil, and a second scanning means located at said pupil. The two scanning means provide orthogonal line and frame scans.

Abstract: A method and apparatus for generating a raster image, in particular when using thermal or infra-red radiation, using a suitable optical means to guide image strips of the object over a set of detectors consisting of several detectors mounted normally to the direction of motion of the image strips. The method is improved by passing the strips of the object image twice over the set of detectors (7 ) in one cycle of the optical means (3), the first and second image being relative offset in height.

Abstract: 1.

Abstract: An optical scanning system wherein infrared energy radiating from an object is directed to a Porro prism, such Porro prism being rotatable about the boresight axis of the optical scanning system so that the image of the object rotates, in the image plane of such system about its boresight axis, at an angular rate twice that of the Porro prism. A linear array of infrared detector elements is disposed in the image plane radially from the boresight axis of the scanning system. The angular deviation of the object from the boresight axis of the scanning system is measured by determining: (1) the angular position of the Porro prism when one, or more, of the infrared detector elements in the linear array is energized; and (2) which one, or ones, of such elements is energized.

Abstract: A testing apparatus for making photometric measurements of transmission and reflectance of large parts uses a light beam having a spatially ill-defined energy distribution. A detector for receiving the light beam has a spatial variation in its sensitivity over its sensing area. A diffuser is provided which is disposed in the light beam for intercepting the light beam before it strikes the detector. The diffuser is formed of a white-like plastic and has a thickness which decreases progressively towards the outer edges of the same to compensate for the fall-off in sensitivity of the detector to rays closer to the outer margins of the diffuser or away from the center of the diffuser. The diffuser is formed in two portions in which a portion of the diffuser is in substantially closer proximity to the detector than the other portion to minimize the directional sensitivity of the detector.The apparatus uses an invisible beam which is aimed by a coaxial visible beam.

Abstract: An infrared (IR) borescope device and a method of its use in the boresight lignment of small caliber weapons. The borescope device has a tapered or expandable mandrel for fitting into the muzzle end of a weapon and a housing containing an IR phosphor covered reticle on one side of a light transparent substrate for converting an IR aiming light beam from an IR aiming light mounted on the weapon into a visible spot of light. The housing also contains a collimating optic means for collecting the IR aiming light beam. The IR aiming light beam is aligned on the IR phosphor covered reticle by adjustment of the azimuth and elevation adjustments on the IR aiming light.

Abstract: An optical sighting device consists of a hood with two windows which can transmit radiation within predetermined wavelength ranges to a rotatable reflecting device. The reflecting device receives radiation from one or other of the windows and the hood is rotatable subject to the rotation of the reflecting device. The radiation reflected by the reflecting device is received by two dichroic mirror plates which are suitable for transmitting or reflecting thermal infra-red radiation, visible radiation and near infra-red radiation towards suitable corresponding detectors.

Abstract: A radiation scanning-detecting and processing system having a composite detector arrangement including detector elements having mutually different sensitive areas. An information processing system coupled to such detector arrangement is effective in response to certain operational parameters to selectively vary the relative contributions of detector elements having different sensitive areas to the overall signal derived from all detector elements in combination.

Abstract: A scanning mirror position sensor operable from the back side of a scanning mirror which utilizes the front side of the mirror for scanning a scene to be interrogated or displayed. A rectangular uniformly distributed light source is reflected from the back surface of the scanning mirror across a grating consisting of alternate transparent and opaque regions placed in the focal plane in front of a single large area photodetector. As the light from the light source sweeps across the grating, the detector is alternately energized and deenergized to form a serial pulse train which is coupled to a pulse counter which accumulates the pulse count to thereby provide a continual and accurate measure of the mirror position.

Abstract: A portable device providing visual images of infra-red sources by means of I.R. detectors/electric signals/light emitting diodes. Scanning is employed to reduce the numbers of I.R. detector elements and L.E.D.'s, the scanning being effected by a rotating polygon having mirror facets tilted at slightly different angles to scan the object and image fields simultaneously in strips which cover the respective fields in a cycle.One aspect of the invention consists in tilting the I.R. and visual facets oppositely to transfer a low I.R. strip position to a correspondingly high visual strip position and vice versa.A second aspect consists in using a polygon with 45.degree. facets and I.R. detectors and L.E.D.'s on optical paths parallel to the axis of rotation. The scanned strips are then symmetrical about their field center lines.

Abstract: An aperture stop is provided near the detector imaging lens of a thermal imaging system to prevent the infrared detector from viewing portions of the thermal imaging system itself, particularly the walls of the optical housing and the housing of the scanner within the optical housing. This eliminates "shading" problems which can occur in thermal imaging systems having a moving scanner within the optical housing.

Abstract: An infrared acquisition device is described which surveys a relatively large field of view in which an emissive target is likely to appear. An optical system focuses an image of the target onto a mosaic of separate detectors arranged in concentric fields and so arranged that the appearance of the target image on the outer or peripheral field will reposition the optical system so as to move the image onto the inner or central field. Chopper means are provided for modulating the signal for processing into servo control signals and also for discriminating against background radiation.

Abstract: The invention provides a particular prism arrangement suitable for use between a source of infrared image and a receiving element suitable for receiving infrared radiation. The prism provides for a line scanning of the image and for this purpose is provided with side faces suitably arranged to provide for the scanning of a multiplicity of lines.

Abstract: Accurate pointing of an infrared receiver or transmitter is provided by boresighting using a special beamsplitter and visible spectrum transmitting optics. The beamsplitter reflects the infrared signal and transmits visible light which permits sighting through the receiver field optics for accurate boresighting or pointing.

Abstract: A device for measuring the radiation from an object by means of an optical system. The optical system comprises scanning devices for horizontal and vertical scanning with refracting rotating prisms. At least one radiation reference source is arranged in the optical system along the path of radiation from the scanned object so that the radiation source can be scanned by the rotating prisms at intervals which are not coincident with the interval when the object is scanned.

Abstract: An object-space scanning system for radiation wherein the scanning device comprises sets of planar reflecting surfaces arranged in pairs, one from each set, such that the two surfaces in a pair are disposed substantially at right angles to each other and the line of intersection of the surfaces is at right angles to the axis of rotation of the scanning device which is so arranged that incident radiation is sequentially reflected from the two surfaces of a pair before entering a focussing arrangement which focusses the radiation into a detector, the secondary scan direction being achieved by the fact that the angle included between the planar reflective surfaces of respective pairs differs by a very small angle successively around said axis.

Abstract: A dome for protecting energy responsive instrumentation in a missile is disclosed which utilizes a plurality of wedge shaped transparent elements mounted in a polymer matrix. The transparent elements are arranged so that aerodynamic pressure acting on the dome compresses each transparent element and prevents dome implosion. Individual elements may crack under excessive aerodynamic load, but are held in place by adjacent elements and by aerodynamic pressure, and retain their optical transmissivity during final trajectory to the target.

Abstract: A wide angle radiant energy detection apparatus arranged as a catadioptric assegrainian telescope having a plane secondary mirror is disclosed which utilizes a correcting lens as a structural support for the secondary mirror to reduce losses caused by mirror support structure vignetting. Angular resolution at wide field angles is increased by lenses which reduce oblique spherical aberation, spherical aberation, and coma, and by the more uniform energy distribution across the image field caused by the lack of vignetting optical support structure.

Abstract: A two-dimensional, AC-coupled, wide dynamic range, mosaic infrared sensor is realized by apparatus that divides incoming infrared radiation into two equal beams. Each beam is received with or without optical concentration by an infrared detector array consisting of a multiplicity of spaced, parallel columns of electrically insulated, independently wired infrared detector elements. The detector element column widths of each detector array are substantially equal to the intercolumn spaces of the other detector array and the columns of each are optically aligned with the intercolumn spaces of the other.

Abstract: Monitoring the peak temperature of a moving mass, such as a flowing stream of molten material, has in the past been plaqued with problems. The present system and method overcomes these problems by oscillating a temperature sensor, spaced from the moving mass, such that the sensor scans back and forth across the moving mass during each cycle of oscillation. The output signal from the sensor is fed to device that preferably puts out a signal proportional to the peak temperature sensed by the sensor on each half cycle of oscillation, which output signal is caused to decay at a desired rate between peak temperature measurements. This slightly sawtooth shaped output signal can be recorded and/or used for control purposes.

Abstract: A radiation scanning system comprising a focusing lens which forms an image of radiation received from a field of view and a curved reflector is arranged to reflect radiation onto a plane mirror which is mounted for oscillatory motion about a fixed axis to thereby scan the radiation image. A relay lens is interposed between the plane mirror and a radiation detector and in the plane normal to the axis about which the plane mirror oscillates the radius of curvature of the curved reflector approximates to twice the radius of curvature of the scanned image and in this way the scanned image is presented to the detector at a substantially constant angle.

Abstract: An infrared gas analyzer is provided with a first path for reference radiation and a second path for measuring radiation. A source emits infrared radiation into the first and second paths. A detector arrangement is positioned at the ends of the paths for sensing the intensity of reference and measuring radiation passing through the paths. A radiation-travel-control arrangement alternately blocks one and then the other of the two paths and during the blocking of each path causes radiation directed towards the blocked path to be deflected into the unblocked path so that such radiation is not wasted.

Abstract: A system for remotely measuring velocities present in discrete volumes of air in which a CO.sub.2 laser beam is focused by a telescope at such a volume, a focal volume, and within the focusable range, near field, of the telescope. The back scatter, or reflected light, principally from the focal volume, passes back through the telescope and is frequency compared with the original frequency of the laser, and the difference frequency or frequencies represent particle velocities in that focal volume.

Abstract: A system for remotely measuring vertical and horizontal winds present in discrete volumes of air at selected locations above the ground. A laser beam is optically focused in range by a telescope, and the output beam is conically scanned at an angle .theta. about a vertical axis. The backscatter, or reflected light, from the ambient particulates in a volume of air, the focal volume, is detected for shifts in wavelength, and from these, horizontal and vertical wind components are computed.

Abstract: An improved radiation energy detecting system is disclosed. The system comprises a rotating scanning mirror reflecting energy radiating from objects in the field of view through a novel image derotating prism, providing optimum transmission modulation transfer and minimal dimension for packaging, and focusing optics onto a radiant energy detecting array. The detector converts the radiant energy to electrical signals representative of the impinging radiant energy for display processing.

Abstract: A missile guidance system is disclosed which utilizes one optical system for visually tracking a target and directing a missile thereto by means of infrared (IR) energy emitted from the missile. The optical system includes a single objective lens for receiving both visible and infrared energy and directing those energies on a first prism. The first prism separates the visible energy from the infrared energy and directs the visible energy to an eyepiece for a viewer. A first image of infrared energy is directed to a first infrared sensor by a retrodirective reflector. A second image of infrared energy is directed at a second sensor by a rotating prism. The output signals from the first and second sensors are provided to missile control circuitry which compares these signals with reference signals and thereby generates command signals for steering the missile to the target.

Abstract: An infrared line scanning instrument is provided which scans a single line in a field of view of the instrument. The scan is performed by a scanning mirror which is transparent in the visible and reflective in the infrared region of the spectrum. The infrared radiation is applied to an infrared detector which feeds a display in the form of a light-emitting diode array to light an element in the array in accordance with the amplitude of the IR irradiance seen by the instantaneous field of view throughout the scan. The display is superimposed from the back side of the scanning mirror upon the visible field of view seen by the observer and/or a camera. The instrument thus generates a record of the thermal profile of a single line of a viewed target which is spatially correlated with its location on the target.

Abstract: An automatically controlled reference temperature strip for sensing by detors in a thermal imaging system. The signal in each video channel from each related detector is integrated to determine which detector is sensing the hottest target signal and to use the output of this hottest signal video channel for controlling said reference temperature strip.