Abstract: A universal multifunction sensor having multiple optical designs and providing a plurality of parameter sensors in one sensor module which can interface with and control operation of one or more processor control systems in an occupied space networked environment. The universal multifunction sensor comprises a passive infrared occupancy sensor and an ambient light sensor. A common network communications and control processor coupled to a common communication transceiver are shared in common by the occupancy sensor and the ambient light sensor, such that the multifunction sensor can interface with and control operation of one or more processor control systems in an occupied space networked environment.

Abstract: A selector assembly for use in avionic multifunctional displays to perform quadrature and push button functions is described herein. The selector assembly utilizes two sensors and a cylindrical band with an encoder pattern having three distinct zones to sense either direction of rotation (quadrature) of a knob or its push motion. The pattern can include regions that are absorptive and reflective to infrared (IR) energy. The selector assembly uses the two sensors to sense a pattern rotation or a push motion of the pattern, thereby reducing the number of mechanical and sensing components and simplifying the wiring associated with the assembly. The encoder pattern is molded either directly on the inside of the knob or on a label that is adhered to the interior surface of the knob. The physical components and the sensors of the encoder mechanism are also placed within the knob of the selector assembly, thereby optimizing the useable glass surface area available for avionic displays.

Abstract: The present invention relates to a proximity detecting device for detecting the presence of an object in a target area, comprising a low voltage power source, a circuitry for generating electrical pulses and supplying them to a light emitting diode (LED) in order to emit light pulses, and a receiver for reception of light pulses emitted from the LED and directed towards said target area, characterised in that said circuitry comprises a first circuitry containing a primary coil and switching means for connecting the primary coil for a period of time to said low voltage power source such as to accumulate a predetermined amount of magnetic energy in the primary coil, and a second circuitry containing said LED and a secondary coil magnetically coupled to said primary coil to transform the accumulated magnetic energy by mutual induction upon opening said switching means each time into one of said electrical pulses.

Abstract: A force-measuring apparatus is provided having a first plate, a second plate disposed above the first plate and spaced apart from the first plate, an optical sensor having at least one optical fiber disposed between the first plate and the second plate, and a clamp for moving the first plate and the second plate together to compress the optical fiber, thereby applying a prestressing force to the fiber to reduce eccentricity effects.

Abstract: For continuous monitoring of dynamic loads, including stresses and strains in large hull structures for vessels (5), a strain measurement system (2) is employed with fiber optic cables which connect optical strain sensors (7; 16) at different points in the hull structure. Optical signals for detection of stresses and strains are distributed to the strain sensors (7; 16) from an optical transmitter (11). The strain measurement system (2) is connected via a central monitoring unit (10) to a computer-implemented control system (1) which in turn is connected to a display and data presentation unit (4) and possibly other measurement systems (3). In a first operating mode, strain values during loading and unloading of the vessel (5) are detected by the strain sensors (7; 16). The control system (1) generates a curve which shows an average strain, and an alarm signal if the average strain exceeds a predetermined threshold which indicates an unacceptable level of strain.

Abstract: This invention is a video security system (10) and a method for visually monitoring a scene and detecting motion of an intruder within the scene. A camera (C) continually views the scene and produces a representative signal. A processor (12) processes the signal and produces an image (f2) represented by the signal. This image is compared with a similar image (f1) of the scene from a previous point in time. Segments of the later image which differ from segments of the earlier image are identified. A discriminator (14) evaluates these segments to determine if the differences result simply from lighting changes, or the movement of an intruder within the scene as indicated by surface differences between segments of the respective differences. If caused by an intruder, an appropriate indication is provided. An algorithm is employed by which differences from one image to another caused by global or local lighting changes effects are identified so as not to produce false alarms.

Abstract: A proximity detector including a rapid transistor (i.e., one having a very high product gain-band) connected to a high potential voltage via a capacitor. The capacitor is connected in series to a source of a pulsed current that is a function of the proximity of an object. The capacitor is also connected to a low potential voltage via an RC circuit. The mid-point of the RC circuit is connected to the collector of a transistor connected to the high potential voltage by a collector resistor in parallel with a gain resistor of the amplifier.

Abstract: A pressure sensor relies on detecting multiply scattered light within an optical cavity. Changes in the volume of the cavity are sensed by the change in sampled light intensity. Pressure sensitive mats with a high density of sensor are assembled using optical fiber technology.

Abstract: An auxiliary switch provides an output or feedback signal indicative of the position or logical state of a contactor, disconnect or other principal device to which it is coupled. The switch is formed as a modular unit which can be fixed directly to the principal device, and is actuated by movement of elements within the principal device. An optical switch set within the auxiliary switch includes an emitter and detector pair aligned in mutually facing relation. An actuator is movable with the principal device and supports an optical shield. The actuator displaces the shield between a position clear of the optical path and a position interposed between the emitter and detector to change the state of the auxiliary switch. A power supply circuit may be housed within the switch for supplying power to the optical switch and to output circuitry. The device is particularly tolerant to contamination and can reliably output low level logic signals indicative of the state of the principal device.

Abstract: A portable, low cost, laser detection system which generates an alarm signal that can be used to produce visual and/or audible warnings indicating the range, location and type laser energy detected. Such laser detection system utilizes a cooperating quadraplex sensor assembly, to provide a complete 360 degree laser detection coverage, mounted on a helmet assembly which includes a helmet shell, a cushioned impact liner coextensive with the interior surface of the helmet shell and a suspended crown support liner the combination of which provides enhanced protection of the user and stabilization of the laser detection system.

Abstract: A security system (40) monitoring displacement between a first, fixed unit (20) and a second, movable unit (21) normally in close proximity to each other. A code generator (51) in the first unit (20) generates a coded electrical signal (Sc) supplied to an optical transducer (24) that converts the signal into an optical signal transmitted at the second unit. A transducer (34) in the second unit receives the transmitted signal, converts it back into an electrical signal now supplied to a code generator (56) in the second unit This generator determines if the electrical signal corresponds to the coded signal. If so, this second code generator generates a second coded electrical signal which is supplied to a transducer (35) in the second unit that converts the signal into an optical signal transmitted back toward the first unit. A transducer (28) in the first unit receives this reply signal and converts it back into an electrical signal.

Abstract: A proximity detection apparatus for detecting objects within a predetermined region. The apparatus comprises a transmitter, a receiver, a microcontroller, and a power supply that provides electrical potential to the transmitter, the receiver, and the microcontroller. The microcontroller produces transmitted data bursts to the transmitter, the transmitter emits optical data bursts toward the predetermined region where, if the object is present, the optical data bursts reflect off of the object as return optical bursts. The receiver detects the return optical bursts and transmits received data bursts to the microcontroller. The microcontroller compares the received data bursts against the transmitted data bursts to verify that the object is present in the predetermined region. The microcontroller produces an output signal to control equipment based the object being present or absent from the predetermined region.

Abstract: When installed on a door to a room, e.g. a restroom, or other area where it is desired to monitor occupancy status of the room or other area, a light source (e.g. a light emitting diode) outside the room or area provides a visual signal to those outside the room or area whether it is occupied (flashing) or not (dark). Optionally there is a second light source, or other indicator, inside the room or area that signals, simultaneously with the outside light, to an occupant of the room or area that the device is properly working. Optionally "occupied" and "unoccupied" signals are sent to a remote station to keep a remote observer informed of the occupancy status of an out-of-sight room or area. For example, the remote signalling option can be used by persons to avoid useless trips to a distant restroom that is already occupied. Preferably an infrared sensor mounted in a cylindrical reflector in a casing mounted on the door senses movement of an occupant during a pre-set time period, i.e.

Abstract: A system for monitoring strain in concrete structures comprises a frame for mbedding in the structure with first and second ends of the frame proximate an edge of the structure, a fiber-optic cable mounted on the frame and extending substantially from the frame first end to the frame second end, a light source in communication with a first end of the cable, a light detector in communication with a second end of the cable, and an information processor in communication with the light detector. The cable is adapted to propagate light from the source to the detector, and the processor is adapted to identify strain in the structure from data generated by the detector.

Abstract: A device is disclosed for measuring light scatter by particles (3) suspended in a carrier medium with a view to ascertaining the density, size or size distribution of the particles. The device comprises: at least one light source (8) which directs light onto a light-scattering center (2) in the carrier medium with the suspended particles (3); a receiver (4) to pick up a portion of the scattered light from the light-scattering center; and an evaluating device connected downstream of the receiver (4). The invention provides for an elongated detection chamber bounded radially around its central axis by the wall of a housing (1) which also acts as a duct for the through-flowing carrier medium with the suspended particles (3). Each light source (8) is mounted on the wall of the housing (1) and points toward the central axis of the detection chamber.

Abstract: A device which assists those who are visually impaired or handicapped and, in particular, a system for warning blind or visually impaired travelers that they have entered a potentially dangerous area proximal to an edge of boarding platforms of the type typically found in railway and other types of transit systems. An Infrared Integrated Indicating System (IRIIS) includes an array of optical emitters and a portable detector/warning device to be held by a visually handicapped traveler. The emitters create a beam of light which bathes a section of the platform proximal to the platform edge. As the visually handicapped traveler moves into a region of the platform covered by the beam of light, a first indicator, such as sensors in the warning device, is activated and by audio, tactile or other stimuli, alert the visually handicapped traveler of entry into a hazard zone. A second indicator provides additional confirmation to the visually handicapped traveler that doors are open as he or she prepares to board.

Abstract: A waveguide switch is provided in which energy such as ultrasonic optical, electromagnetic or infrared waves travel in a first waveguide having fixed length formed in a first member connected to a second member having multiple waveguides of varying lengths which may be rotatably mounted to the first waveguide in order that upon rotation of the first or second member, different waveguides may be aligned to form an overall position identifying waveguide of varying lengths in order to provide a means for controlling a component attached to the switch. A transmitter and a receiver are mounted within the waveguide and connected to a detector in order to convert the time-of-flight data of the waves to an electrical signal.

Abstract: An article having an optical fiber integrally attached to a micro-device having spaced movable and nonmoving layers suitable for creating optical interference effects is disclosed. In one configuration, the micro-device is suitable for optical modulation, wherein the movable layer is electrostatically actuated to move towards the nonmoving layer. Such movement changes the size of the gap between the layers, resulting in a change in micro-device reflectivity. An optical signal is modulated by controlling micro-device reflectivity via a controlled voltage source. In a second configuration, the micro-device is suitable for measuring pressure. For pressure measurement, the movable membrane moves in response to pressure changes. The change in membrane position again results in a change in micro-device reflectivity. Reflectivity is correlatable to pressure. In a third configuration, the micro-device is suitable for measuring temperature.

Abstract: A surveillance system comprising a motion detector is secured by a security system comprising a light emitter and light receiver optically coupled to light guides positioned, for example, along the circumference of a light-transmitting window that covers the motion detector. In this manner the window is secured against damage or attack on its integrity, for example, in the form of a film covering or sprayed on the window. The security system delivers an alarm signal when the detected light intensity level is too low or too high.

Abstract: A method and system for providing improved confined area audio amplification is provided. Designed to meet the requirements of classrooms, conference rooms and offices, this new invention provides improved signal-to-noise ratio, improved system redundancy, and higher voice audio quality than is offered in previous systems. This invention utilizes infrared as the wireless communications channel, and does so with two receivers, a master and a slave to provide redundancy in signal reception and thereby solving one of the long standing problems with line of sight communications systems. This invention also employs a pulse position modulated signal which has higher noise and interference immunitity that is available with prior systems. This invention is flexible with a lightweight, wireless, battery operated transmitter packaged in a necklace type of holder, suitable for wearing around the neck of the speaker.

Abstract: A detection sensor with a single switch for multi-function programming of the sensor is disclosed. The sensor has a processor operatively connected to the switch, an emitter, and a detector for controlling one or more operational parameters of the sensor in response to a program signal from the switch. In the preferred embodiment the processor compares a signal detected by the sensor in a first state and a second state and automatically establishes the sensor amplifier gain and switching thresholds based on the signal difference in the two states.

Abstract: A vehicle security system 10 having a sensor 28 which selectively produces output signals based upon a threshold signal comparison, which automatically deactivates upon the presence of transmitter 20, and which may be used in combination with an existing vehicle security system 106.

Abstract: An isolation amplifier that transmits data to a receiver via a current loop, where the isolated portion of the circuit is powered by a photovoltaic array illuminated by a light source powered directly by the current loop. Optionally, the photovoltaic array is additionally illuminated by any excess power tapped from the current loop by the non-isolated portion of the circuit. Preferably, the light source is an array of light-emitting diodes. Preferably the photovoltaic array is an array of photocells sensitive to the same wavelengths emitted by the light-emitting diodes. Preferably, there are optical conductors connecting the LED's to the photocells.

Abstract: A food storage apparatus comprises a container (140) for containing a food item, and a cover (142) for covering an opening of the container (140). A first electrical component (144) is associated with the container (140). A second electrical component (146) is associated with the cover (142). The first electrical component (144) communicates with the second electrical component (146) to monitor the food item.

Abstract: The garage door position indicator contains a radio frequency (RF) transmitter with an electronic angle sensor attached onto a garage door, and a RF receiver with a visual/audio indicator. The electronic angle sensor supplies signals to the RF transmitter during the changes in orientation of a garage door from vertical to horizontal and from horizontal to vertical. The RF receiver is responsive to the RF signals from the RF transmitter and controls a visual/audio indicator to indicate the position of a garage door accordingly.

Abstract: A device and a method for eliminating interference signals in a light barrier. The device includes, having a transmitter, a receiver and an evaluation unit that is connected to the receiver. The transmitter periodically emits light pulse trains with a defined pulse length T.sub.P and a defined period length T.sub.s. In the evaluation unit, the received signals present at the receiver are evaluated only during activation intervals that are limited in time. The length of the activation intervals depends on whether light pulses are recorded during these activation intervals.

Abstract: The multiple scattering of coherent radiation in an inhomogeneous medium is used to detect attempted intrusions into a protected area or into a tamper-proof package for such purposes as preventing the unauthorized detection and copying of electronic information used for authentication and coding in electronic commerce, communications, command, and control systems. A key advantage is that any intrusion into the sensed volume will produce a detected change in the measured intensity which will be equal to the full amplitude range if the intrusion is into a cylinder with radius comparable to the wavelength of the sensing radiation. The response of the medium can also be used to provide a unique identity key.

Abstract: An alarm system and method for detecting an intruder and making an impression on the intruder. The system operates by detecting a presence of the intruder, determining a location of the intruder, outputting a warning signal for perception by the intruder, and changing the warning signal based on the determined location of the intruder and/or a predetermined passage of time. The system provides means for changing an audio level of the warning signal gradually so as to give the intruder an impression that an audio source is moving toward the intruder. In a preferred embodiment, the warning signal is output over a plurality of speakers, and a phase and audio level of the warning signal output from a first speaker is changed relative to a phase and audio level of the warning signal output from a second speaker so as to give the intruder an impression that an audio source is moving two dimensionally toward the intruder.

Abstract: Apparatus (10) for monitoring vehicle (V) usage on a roadway (H). An AC light source (12) comprises either an incandescent or gas discharge light source. The light source has a detectable AC ripple in its output. The light source is mounted or installed above the roadway surface on a conventional light standard (16) or highway information standard (18) such that the light source directs its rumination downwardly onto the roadway. A light detector (34) detects light reflected from off the roadway. Light from the light source together with the collection optics of the light detector define a "footprint" (30) on the roadway surface and vehicles moving over the roadway pass over this footprint. The directed, reflected light has characteristics which are varied in response to passage of a vehicle over the roadway and through a path (X1, X2) of light between the source and detector.

Abstract: An optoelectronic device for measuring the ground contact time and position of a body within a preset region, having a first measurement bar, which includes one or more infrared light beam transmitters, and a second measurement bar, which is arranged opposite and parallel to the first bar and includes one or more receivers, the number whereof is equal to the number of transmitters present in the first bar. The first and second bars are connected one another by means of an electrical line and form a measurement area therebetween.

Abstract: A light sensitive switch for the activation of an alerting circuit (70) to be used as an electronic alerting device (50). Alerting device (50) may be used in publications such as a magazine (78) or book (94) to enhance the printed material by audio visual and/or mechanical vibration means. A photosensor (52) is used to detect ambient light when the publication is opened to an activation page (86) where the enhancement is located. Photosensor (52) switches on a transistor (66) when exposed to light, which in turn switches on alerting circuit (70). Alerting circuit (70) may consist of an audio transducer (74), a lamp (76), a motor (128), a solenoid (136), a mechanical vibrator or any combination of these. Pages are used to block ambient light from photosensor (52) when the publication is closed, thus turning off alerting device (50).

Abstract: A multi-functional anti-theft supervising assembly which has an overall configuration of a telephone, includes an anti-theft controller, a video monitoring circuit, a dialogue controlling circuit and an infrared detecting circuit. A monitoring window, screen and a handset are provided as well. The anti-theft controller is connected with a plurality of signal detecting circuits externally and an infrared detecting circuit, accordingly, the signal of anti-theft, flameproof, gas-leakage can be transmitted to the hoist computer located at the control center for suitable reaction. The video controlling circuit and screen can be connected with the camera disposed at the front door. The dialogue circuit is connected as well. The dialogue circuit and said handset are interconnected with said video controlling circuit. A door lock release circuit is connected as well.

Abstract: A light-emitter emits light, and a plano-convex condenser lens focuses the emitted light and projects the focused light onto a floor near a door to thereby establish a sensing area. A plano-convex light-receiving lens focuses light reflected from the sensing area, and a light-receiver receives the focused, reflected light. The plano-convex lenses have edges closer to the door which is substantially straight.

Abstract: A sensor system to turn on room lights when a person enters such room but avoids nuisance tripping of the system when a person passes near but outside of the region to be monitored. The inclusion of blinder devices which can be individually set, ahead of the sensor elements, permit the region being monitored to be tailored to the particular room or location. Adjusting levers can be used to set the positions of the blinder devices and then covered to prevent tampering with the settings of the blinder devices. Special fasteners can be used to limit access to the adjusting levers.

Abstract: An apparatus for selecting and controlling devices located remotely from a local site where an operator resides. A laser or other source of a focused electromagnetic bean moves in association with a camera located at the remote site. The camera thus can detect the object on which the focused laser beam projects. The camera outputs a video signal which is transmitted from the remote site to the local site. The operator at the local site views the video signal on a monitor so that the operator can determine the location of the laser beam. When the laser beam illuminates at least one particular transponder out of one or a plurality of transponders, the transponder outputs a signal to at least one device to activate or deactivate the device, thus providing the operator remote control of the device. A light may also be associated with the transponder and activates when the transponder has been selected to provide a positive indication to the operator that only the particular transponder has been selected.

Abstract: An infrared detector including a sensor which provides an output signal responsive to infrared radiation incident on a face thereof, and a diffractive optical element which directs a substantial portion of incident visible radiation away from the sensor and which has substantially no diffractive effect on incident infrared radiation.

Abstract: A method is described for transferring data from an unsecured computer to a secured computer. The method includes transmitting the data and then receiving the data. Next, the data is retransmitted and rereceived. Then, it is determined if errors were introduced when the data was transmitted by the unsecured computer or received by the secured computer. Similarly, it is determined if errors were introduced when the data was retransmitted by the unsecured computer or rereceived by the secured computer. A warning signal is emitted from a warning device coupled to the secured computer if (i) an error was introduced when the data was transmitted or received, and (ii) an error was introduced when the data was retransmitted or rereceived.

Abstract: A fiber optic sensing system and method comprises a continuous optical fiber including at least three mirrors defining at least two contiguous optical cavities. Preferably, each optical cavity has a unique length so that the reflected optical signal associated with a given optical cavity will have a unique phase difference or wavelength allowing each of the respective optical signals to be selectively detected. A physical phenomenon acting on a given optical cavity can be sensed by determining changes in the respective optical signal reflected from that optical cavity. This sensing system allows a single optical fiber to include both integrating and point sensors. In addition, this system can be incorporated in smart structures.

Abstract: A FM (VHF) infrared wireless digital metal detector is disclosed having a sealed aluminum radiation shield and dielectric case, with a infrared phototransistor detector and krypton bulb arranged to relay detection data to meter within a clustered instrument combination down in front of metal detector unit.

Abstract: A high speed secure fiber optic communication system that includes a coherent alarm system utilizes a pair of single mode fiber optic cables in combination with one or more light sources, phase modulators, detectors and polarization scrambling elements to form a Sagnac interferometer. The phase modulator is driven so that counter propagating light beams in the Sagnac loop experience a different optical path as they pass through the loop. When the two beams are recombined on the central beamsplitter of the Sagnac loop, the two beams interfere with each other and the data impressed as phase modulation on the light beams by the phase modulator is recovered as amplitude modulation on the output detector of the Sagnac interferometer. The coherent alarm system applies a relatively low frequency background signal to the Sagnac interferometer and watches for changes occurring to the background signal that indicate the presence of an intruder.

Abstract: The use of a single concave mirror (1) serving as an optical focusing and directing element for a proximity switch allows an increased sensitivity at equal construction size or a substantial reduction in the construction size with equal sensitivity. In a preferred embodiment, the concave mirror is divided into two halves (3, 4) by a supporting plate (2) for the light source (5) and the light sensor (6), the halves (3, 4) of the mirror serving the purpose of directing the emitted light (8) and focusing the reflected light (9) onto the light sensor. In order to increase the resistance to difficult environmental conditions, the concave mirror (1) or its portions (3, 4) can be filled with a substance which is transparent to the light of the light source (5). Metallized plastics material is a suitable material for the mirror, especially in combination with the mentioned filling substance.

Abstract: A method of defining a sensing system for detecting the presence of an object in a volume of space under surveillance by determining the optimal placement of a plurality of energy beams which are projected into the volume which comprises the steps of (A) placing the object at a preselected position within the space; (B) directing a plurality of sample beams of energy, which have a predetermined orientation, from a source onto the object; (C) detecting the reflections of the sample beam energy from points on the object by energy detectors; (D) recording the preselected position of the object, the predetermined orientation of sample beams, and the detection status of the energy detectors; (E) changing the equatorial and azimuthal angles of each of the beams and repeating steps (B), (C) and (D); (F) moving the source of the sample beams relative to the object; (G) repeating steps (B) through (F) to produce spatial maps of the locations at which the object is positioned when each of the energy detectors detect re

Abstract: A method includes steps of measuring a distance in a straight line to an object within a target area by means of a range finder; storing object data indicative of the measured distance in a memory; repeating the above steps a plurality of times; and comparing n-th object data with (n-1)-th object data to detect whether the object changes in distance to the range finder; whereby recognizing a behavior of the object, and a system includes; a range finder for measuring a distance in a straight line to an object within a target area to output distance data corresponding to the measured distance means for periodically sampling the output distance data; a memory for storing the sampled distance data as object data and means for comparing n-th object data with (n-1)-th object data to output a judging signal representing whether the object changes in distance to the range finder when a difference between both the object data exceeds a predetermined value.

Abstract: A residual pressure sensor for verifying that a residual pressure is zero, and to a monitoring apparatus for monitoring for faults in the residual pressure sensor. In order to detect that a residual pressure has completely gone, the residual pressure sensor detects change conditions in the output therefrom, and an output for no residual pressure is not generated while there are changes. Moreover, an electrical power supply condition to a drive solenoid (21) of a solenoid valve for opening/closing a pressure supply line, is monitored using a fail-safe current sensor (21) which outputs a logic value "0" when the presence of a current is detected, and which outputs a logic value "1" when the presence of a current is not detected. Fault monitoring of the residual pressure sensor is then carried out based on the monitoring output conditions of the current sensor and the output conditions of the residual pressure sensor.

Abstract: A transparent and impervious sphere containing encapsulated within the elronics and power source for providing non-visible infrared illumination and communication in various military and non-military applications and denied-access environments. The illumination and communication light source is invisible infrared provided by light emitting diodes mounted near and equally spaced about the circumference of each of two orthogonally intersecting circular-shaped and fully encapsulated printed circuit boards. The autonomous encapsulated power source is rechargeable using an inductively coupled probe introduced to a port in the sphere. An external magnet operates encapsulated magnetic field switches to change mode of operation of the invention, including "ON", "OFF", CONTINUOUS, STROBE, and Morse modes, and to change the Morse coding.

Abstract: A wearable transmitter assembly includes a housing containing a radio frequency transmitter and tamper detecting circuit that are attached to an appendage of an individual with a buckle and strap. A light emitter and a light sensor are disposed in the housing and extend to the outside of the housing through one or more apertures. The strap includes an embedded optical fiber. Attachment of the housing to the buckle positions the emitter and sensor adjacent the ends of the optical fiber in the strap to complete an optical path or circuit from the emitter around the appendage to the sensor. The housing is sealed closed, including sealant between the emitter, the sensor and the aperture, providing a water tight enclosure for said transmitter from the time of its manufacture. Attachment of the housing to the buckle completes a seal blocking contaminates, such as water, water vapor, and soap from the ends of the optical fiber, the emitter and the sensor.

Abstract: A system is disclosed for detecting the presence of a human who may be observing an artifact which is within his or her line of sight or field of view. The system includes a laser with a lens at the output thereof and which is triggered rapidly in order to produce a pulsed beam having divergent rays of visible or invisible infrared light which irradiates an area to be examined for the presence of an observer. The light reflected from individuals and objects in the area is reflected into a pair of vision devices or pair of vision device assemblies the outputs of which are fed into a computer. The computer has software programs which utilize vision device output data relating to the intensity and location of the light pixels in the image thereof to detect the presence and orientation of the eyes of an individual in the area based on the light pixel intensity and location data.

Abstract: Motion is detected from a surveillance monitor by means of a photosensor attached to the monitor screen and an electric circuit connected to the sensor which generates an alarm signal in response to changes in the level of an electric output signal generated by the sensor. The sensor is housed within a suction cup which is readily attached to any part of the screen and is readily movable to any desired area of the screen to be monitored for motion. The electric circuit includes comparators which detect changes in light intensity greater than a predetermined magnitude defined by a window about a preselected voltage level. The circuit includes an operational amplifier and a transistor connected to the output of the sensor and the circuit provides an effective impedance equal to the impedance of the sensing device at various levels of intensity such that the reference voltage level, for detection purposes, is the same at all levels of steady state light intensity.

Abstract: A key operated door lock assembly comprising an operator assembly rotatable from a door open to a door closed position, including an operator, a plug in the operator having a key receiving opening, a support assembly for the operator assembly secured to the door including a light source operable for a predetermined period of time, and a first light pipe having a first end for receiving light from the light source and a second light transmitting end. Means for remotely operating said light source for a period of time selected so that a person can insert a key into the key receiving opening and rotate the operator assembly from the door closed position to the door open position. The operator assembly further includes a second light pipe having an exposed light transmitting portion and a light receiving portion, and means for supporting the second light pipe so that the light transmitting portion of the second light pipe is adjacent the key receiving opening.

Abstract: The invention relates to an optical pressure detector for instance in the form of an optical alarm with a multimode light guide (1) imbedded in a contact pad (2) subject to pressure, said light guide being curved by the compression of the contact pad (2). The light guide (1) is mounted between a light source and a light detector, an analyzer being present to analyze the output signals from the light detector changing through mode coupling as a function of the applied pressure, and to process them for instance into an alarm signal. The light detector covers an angle of aperture at the exit of the light guide (1), said angle only enclosing the radiation field in the range of lower-order modes of the light guide (1).