Abstract: Optical coupling device operates over a bidirectional data link between at least first and second communicators, each communicating data along a common wire of the data link. The device includes at least first and second optical couplers, each including a photon flux source and a photon flux detector. The photon flux source of the first and second optical couplers, respectively, is commanded by the first and second communicator, respectively. The photon flux detector of the first and second optical coupler, respectively, produces a signal on the data link at the first and second communicator, respectively, in response to the photon flux source of the second and first optical coupler, respectively, from the second and first communicator, respectively. An inhibitor inhibits the photon flux source of the second and first optical coupler, respectively, in response to an activation of the photon flux source of the first and second optical coupler, respectively.

Abstract: To provide a multi-optical axis photoelectric sensor and a multi-optical axis photoelectric sensor system, which enable function setting by an extremely simple operation, and further make it unnecessary to increase the size of a housing or to separately prepare a PC or a function setting tool. The multi-optical axis photoelectric sensor has: a columnar housing, from one end of which in the longitudinal direction an electric cord is pulled out, and at the other end of which in the longitudinal direction a plug-in type socket is provided, and a plug piece detachably attachable to the socket of the columnar housing. Particular information to serve as a function determining element on the columnar housing side is incorporated in the plug piece in a manner referenceable from a processing circuit on the columnar housing side via the socket. Further, the processing circuit on the columnar housing side is set so as to determine a function based upon particular information in the plug piece referenced via the socket.

Abstract: Systems and methods for detecting presence and movement of intruders. Various embodiments of an intruder detection system can be based on, for example, a beam-interrupt detector or a thermal imaging device. The beam-interrupt detection based system can provide functionalities such as counting of intruders crossing a given beam. A plurality of such beams at different heights can also allow distinguishing different-sized intruders. The thermal imaging based detection system can provide functionalities such as tracking movement of intruders. A recording can be triggered by detection of intruder movement, thereby improving the efficiency of recording and reviewing information indicative of presence and movement of intruders in a monitored area. In one embodiment, non-intruders can be distinguished from intruders by querying an RFID tag carried by non-intruders. In one embodiment, non-intruders can be distinguished from intruders by facial recognition.

Abstract: An intruder detection and warning system has a plurality of infrared sensors for receiving infrared radiation from respective contiguous areas of premises in need of security. A central illumination unit including a rotatable light is operated to project a beam illuminating a selected one of the contiguous areas of the premises in response to the received infrared radiation by the infrared sensor in the selected area indicating presence of a person in the selected area. Initially a polite message randomly selected from a group of different polite messages is broadcast to request the intruder to leave the premises. When continued presence of the intruder is detected, the light beam is moved away from and then back to the selected area and a further message randomly selected from a group of different more demanding messages is broadcast to demand the intruder to leave the premises.

Abstract: The present invention provides a multiple-optical-axis photoelectric sensor in which an error in detection of an object caused by disturbance light is prevented easily and efficiently by adjusting a light projection/reception cycle in accordance with a state where mutual interference is recognized. In the invention, by detecting a range in which mutual interference occurs, that is, the position in which disturbance light is detected, which is either a first-half period or a latter-half period of a whole light projecting/receiving operation period, whether the phase is advanced or delayed is determined. For a period according to the position of the optical axis in which incidence of disturbance light is recognized or the number of optical axes in which incidence of disturbance light is recognized continuously, a scheduled next sync timing is changed.

Abstract: A light grid for measuring an object and securing a dangerous zone of a machine has an emitting unit with individual light emitters for directing a plurality of light beams in the form of emitted light cones approximately along a lit plane. A receiving unit is spaced apart from the emitting unit and has individual light receivers for receiving light from the emitted light cones. The emitting unit and the receiving unit define a protected zone between them. The emitting unit and/or the receiving unit has at least two differently formed first and second optics. The first optics generate the emitted and/or the received first light cones. The first light cones have a greater dimension in a direction parallel to the plane than in a direction transverse to the lit plane. The second optics generate a second emitted and/or received light cone.

Abstract: A sensor unit including: two or more individual sensors; and alignment mechanism for aligning at least one of the two or more individual sensors with another sensor or a source to maximize a transmitted signal therebetween. Also provided is a method for maximizing a transmitted signal between sensors and/or sources in a sensor network. The method including: arranging two or more of the sensors in a package; and aligning at least one of the two or more sensors in the package with at least another sensor or a source.

Abstract: The present invention relates to an enhanced perception lighting (EPL) system for providing enhanced perception of a user's physical environment. The EPL system comprises a sensor module for detecting and sampling a physical aspect from at least one point in a physical environment and for generating an observation signal based on the physical aspect; a processor module coupled with the sensor module for receiving the observation signal, processing the observation signal, and generating an output signal based on the observation signal; and a projection display module located proximate the sensor module and communicatively connected with the processor module for projecting a display onto the at least one point in the physical environment based upon the output signal. The system allows a user to gather information from the physical environment and project that information onto the physical environment to provide the user with an enhanced perception of the physical environment.

Abstract: A laser-based first warning system for vehicles is principally intended to be used when a vehicle is moving or about to move and can't be seen by oncoming drivers or pedestrians. The first warning system provides lasers on both sides, the front and back of the vehicle to paint a square or other shape on the ground several feet from the hidden vehicle giving warning to anyone that a hidden vehicle is pulling out, or otherwise about to move.

Abstract: To provide a sensitivity adjustable intrusion detecting system capable of detecting the presence of a person assuredly even under the environment where the object such as a person is difficult to be detected, thereby avoiding an erroneous operation, the sensitivity adjustable intrusion detecting system is so designed that since the detecting sensitivity of the main detecting unit 1 is altered in response to detection by the auxiliary detecting unit 2 and when such detecting sensitivity of the main detecting unit is so increased at the time the necessity to detect the presence or absence of the human body H entering in one of the main detection areas encompassed within the supervised sector, the detecting sensitivity of the main detecting unit is increased to allow the human body to be assuredly detected under the environment where the human body is difficult to be detected, thereby avoiding an erroneous operation.

Abstract: A solar powered perimeter beam security system comprising a plurality of spaced towers. The towers have detection beams extending between them for detecting an intruder when at least one of the detection beams is interrupted. Each of the towers communicates with a remote unit. At least one of the towers is movable from one location to another. An alarm. The detection beams define an intruder detection area into which an intruder cannot pass without breaking at least one of the detection beams thereby setting off the alarm. The detection area is expandable and decreasable by moving at least one of the towers. The towers are incapable of movement without setting off the alarm once positioned with the detections beams being activated.

Abstract: A system and method are provided for automatically detecting intrusion in an off-limits zone. The system includes a transmitter transmitting a signal along a path likely to encounter an intruder to the off-limits zone and a modulating reflector for receiving the transmitted signal. The modulating reflector includes a modulator receiving the received signal and generating a modulated signal having a characteristic. The modulating reflector transmits the modulated signal to be received by a receiver located to receive the modulated signal. The system further includes a processor coupled to the transmitter and to the receiver, the processor being configured to process the received modulated signal and to initiate an action as a function of the characteristic in the received modulated signal.

Abstract: A detector mountable on either a planar wall or an interior corner and having an adjustable field of view. The detector includes first and second sensors positioned to provide a horizontal field of view defining an angle of approximately 180 degrees. At least one blinder has a first position wherein the first and second sensors have a horizontal field of view defining an angle of approximately 180 degrees and a second position wherein the first and second sensors have a horizontal field of view defining an angle of approximately 90 degrees. A biasing member biases the blinder toward a first one of the first and second positions. A positioning member has a first member position wherein the positioning member biases the blinder toward the other of the first and second positions and a second member position wherein the biasing member biases the blinder into the first one of the first and second positions.

Abstract: There is provided a security sensor device having an optical axis adjusting capability, which device includes a beam projecting unit (1) for projecting sensing waves, to which ID codes for specifying beam projectors (2) are applied, to a beam receiving unit (8) sequentially at predetermined intervals. The beam receiving unit (8) detects the level of light received by each of beam receivers (9) corresponding to or identified by the respective ID codes and transmits the received light levels to the beam projecting unit (1). According to these features, during the optical axis adjustment the levels of light received by the beam receivers (9) can readily be obtained on the side of the beam projecting unit (1), resulting in an accurate adjustment of optical axis between the beam projectors (2) and the beam receivers (9) in a short length of time with a simplified structure.

Abstract: Apparatus for monitoring hand propinquity to plural adjacent item locations arranged in a generally two-dimensional array including an illuminator, disposed adjacent a first edge of the two-dimensional array and generating radiation which illuminates a generally planar imaginary curtain disposed in front of the plural adjacent item locations, at least one detector, disposed adjacent the first edge of the array and sensing the radiation reflected from a hand traversing the imaginary curtain generally at any location on the curtain and location determination circuitry responsive to at least one output of the at least one detector for associating a sensed position of the hand with respect to one of the plural adjacent item locations.

Abstract: A surveillance detector comprising a light emitter and a light guide which is optically connected to the light emitter, which light guide includes reflectors mounted therein, a special feature being the fact that the light guide is capable of converting the light from the light emitter at least in part into a light beam to be built up in the space to be kept under surveillance, and in that the light guide is capable of guiding light from the light beam that is reflected by an object in the space to be kept under surveillance to a light receiver of the detector, which is optically coupled to the light guide.

Abstract: A safety or security light grid for monitoring a protected field having a light transmitting strip, which has a row of light transmitters arranged alongside each other, and a light receiving strip, which has light receivers arranged alongside each other associated with respective light transmitters, so that a plurality of parallel light barriers form the protected field. There is at least one control and evaluation unit, which controls and evaluates the individual light barriers for generating a warning signal when one or more light barriers are interrupted by an object. The light grid has two input elements and at least one display element for configuring the light grid.

Abstract: A device (10) for detecting the presence of light averse insects, such as termites, is in the form of a peg (11) having a cavity (14) into which termites may enter when the peg is installed in the ground or other area where the presence of termites is to be detected. The cavity may include a termite bait. A light sensor (25) is located in the cavity, and has an output which is responsive to the detection of light. The light sensor operatively receives light from a light emitting device (LED) (23) only through a narrow passage extending through the peg from the LED (23) to the cavity (14). The passage is adapted to be at least partially blocked by the light averse insects to shield the cavity, and hence the light sensor means, from light from the passage. When the light sensor means (25) does not detect sufficient light, an electrical circuit (22) connected to the output of the light sensor means triggers an alarm light (26) to signal an alarm or alert condition.

Abstract: The invention relates to a fiber optic security system and control method thereof which, in detail, is embodied by plural channels each comprising an optical transmitter module, an optical transmission line, and an optical receiver module. The invention is easy to install on windows, doors or fences which need to be secured and improves the degree of security by means of operating the plural channels at random sequence. The present invention takes the effect that the invention makes it possible to cope flexibly with the actual spot to be installed by connecting plural channels each comprising an optical transmitter module, an optical transmission line, and an optical receiver module in order to cope with the dimension of the actual spot to be installed, and by cutting the plastic optical fibers in order to cope with the length of the actual spot to be installed, to maintain conveniently due to the ability of replacing channels one by one, and to reduce maintenance expenses.

Abstract: An information apparatus includes a housing fitted to a support substrate and having a hole portion on a surface opposing the support substrate, a cover part fitted to the housing, and an abnormality detection part disposed inside the housing, including a first movable part urged by first urging force by the cover part in a first direction approaching the substrate support and a second movable part urged in a second direction approaching the cover part by second urging force, and detecting abnormality when either one of the first and second urging forces is released.

Abstract: A detection warning system for caregivers in a home alerting a caregiver when a person exits a room, bed or walk through a doorway. This system comprises of two enclosures and an external reflector. A portable infrared emitter detector enclosure houses an emitter with a narrow, infrared beam, detector and transmitter. A portable receiving enclosure houses a receiver with an adjustable audio alarm. An emitter in the emitter detector enclosure emits an infrared beam to the reflector, which reflects the beam back to the detector. The detector senses when the beam is obstructed from reaching the reflector and energizes the transmitter. The transmitter receives the signal from the transmitter activating the adjustable audio alarm alerting a caregiver.

Abstract: A smoke detection device for use in a portable device such as a mobile terminal. The smoke detection device comprises a light emitter and a light detector disposed on different locations on the portable device so that when smoke or an intruding object is presence in the light path of the light emitter outside the device housing, it causes the light emitted by the light emitter to be scattered or reflected. When the light detector senses the scattered or reflected light, it can cause an alarm signal to be produced by the portable device. The emitted light can be in the infrared region so that the detection is independent of the ambient light. Alternatively, the light emitter is operated in a pulsed mode. Additional light emitter and light detectors can be disposed on the portable device for proximity sensing in addition to smoke detection.

Abstract: An apparatus for detecting objects on an airport runway. The apparatus comprises a first transmitter adapted to be positioned adjacent to the runway, a first receiver adapted to be positioned adjacent to the runway, a processor operably linked to the first receiver, and a user interface operably linked to the processor. The first transmitter is adapted to emit a first beam of light across the runway to the first receiver and the first receiver is adapted to send a first indication to the processor if the first beam of light is interrupted by an object on the runway. The processor is adapted to send a warning indication to the user interface in response to the first indication and the user interface is adapted to generate a warning upon receipt of the warning indication.

Abstract: A keyless access sensor system for use with a keyless access control mechanism (KACM) is described for controlling the operation of a locking device. The KACM receives a signal from a sensor device for keyless access to create a first output signal before the user has begun any action on the handle in order to open the door. The first output signal is sent to a general processor, which initiates a recognition process and, after recognition of the authorized user the processor then generates an unlocking signal which unlocks the locking device before the authorized user will have fully accomplished the action of opening the door. Thus the authorized user is allowed to open the door without any specific un-ergonomic and time-consuming additional action to the simple action of actuating the handle to open the door.

Abstract: A light grid is provided for the detection of objects in a monitoring region having a transmitter unit comprising a plurality of light transmitters and a receiver unit comprising a plurality of light receivers in which respective pairs of light transmitters and light receivers associated with one another and bounding the monitoring region can be activated in succession in time in dependence on a synchronization signal transmitted between the transmitter unit and the receiver unit, with at least one light guide being provided for the transmission of the synchronization signal.

Abstract: A non-destructive flying insect detector is disclosed. The detector creates a sheet or curtain of light comprising a sensing zone and detects, by means of light extinction, individual flying insects that intersect the sensing zone. The sensing zone is created by a beam of light that enters the sensing zone area and is then bounced between opposing reflective surfaces. Preferably a laser is utilized to generate the beam of light. The beam of light leaves the sensing zone area and is incident on a light detection device (such as a photo cell) connected to an amplifier circuit. The light detection device monitors the light intensity and is arranged and configured to detect changes in the light intensity. The changes are electronically converted to a pest detection signal and/or to a flying insect count. Each flying pest detection signal may also be associated with other monitored data.

Abstract: Arrangement for obtaining information about objects in an environment around a vehicle, e.g., in blind spots of the driver of the vehicle, including one or more light emitting components arranged on the vehicle for emitting infrared light into the environment around the vehicle and receivers arranged on the vehicle for receiving infrared light from the environment around the vehicle. The information about the objects is obtained based on analysis of the received infrared light by a processor, e.g., the distance between the vehicle and the object, the velocity of the object and the identity of the object. Pattern recognition techniques are preferably used to obtain the desired information. Control of the vehicle can be effected based on the detection of particular objects and their position and velocity, e.g., an audio or visual warning device or a steering wheel control device.

Abstract: The automobile entry detector for garages is a signaling system designed to assist a motorist with properly positioning a vehicle upon pulling into a parking structure, such as a household garage. This device could be offered in various embodiments, including as an aftermarket accessory for existing garage door openers or as an integral part of a new garage door opener design. The preferred embodiment of the device includes a garage door opener motor and controller, a garage door opener control switch, a light transmitter that transmits a beam of light to a light receptor with an LED indicator, a photocell, and an indicator lamp located on the rear wall of the garage. The LED indicator is extinguished when the beam of light is unbroken, and the photocell relays this information to activate the lamp at the same time as the LED.

Abstract: Sensor(s) may be such that light-projecting component(s) and light-receiving component(s) are arranged therein. Furthermore, such sensor(s) may be provided with optical path varying means for varying projected light optical path(s) and/or received light optical path(s) so as to physically vary overlapping zone(s) in which the projected light optical path(s) and the received light optical path(s) at least partially overlap. The optical path varying means may carry out adjustment of optical sensitivity by increasing the extent(s) of the overlapping zone(s) when carrying out detection with respect to zone(s) distant from such sensor(s) and/or decreasing the extent(s) of the overlapping zone(s) when carrying out detection with respect to zone(s) proximate to such sensor(s).

Abstract: An optical detection system for forming an image of a field of view in an object plane onto an image plane in which the electromagnetic radiation image is transmitted to a detector array at the image plane via an optical distorting element such as a reflector 11, so as to impose a non linear relationship between areas in the image and object planes.

Abstract: To provide an anti-thief security sensor assembly capable of automatically setting a projecting power in such a manner that a received beam amount of the anti-thief security sensor assembly for detecting an infrared beam interrupted to sense an intruder attains a predetermined value during an optical axis adjustment, the anti-thief security sensor assembly includes an infrared beam projecting unit (1) for emitting the infrared beam (IR), and an infrared beam receiving unit (2) for receiving the infrared beam (IR). The infrared beam receiving unit (2) has a received beam amount detector (26) for detecting the received beam amount, and a signal transmitter (28) for transmitting a received beam level display signal (L) indicative of the amount of the received beam detected to the infrared beam projecting unit (1).

Abstract: A secure screen that includes a sheet of robust metal mesh having separate locking devices, located, but not limited to, the top, bottom, left, and right sides thereof that to provide for independent locking locations on the mesh member that are each lockable to one of four separate dwelling structure locations; a motion sensor being mechanically attached to an outer frame of the robust metal mesh member and, if connected to an existing alarm system, such that tampering with the electrically metal mesh member, can activate the alarm system to summon help and, thereby, prevent entry of a potential intruder.

Abstract: An animal handling device, including at least one securing device, and a primary sensor system, and a secondary sensor system characterised in that both the primary and secondary sensor systems must be simultaneously activated in order to trigger the securing device to hold the animal.

Abstract: A photo-detecting method of the present invention includes the steps of projecting from a light emitting element a pulse-modulated light as pulse-modulated at a light-emitting element drive circuit toward an object; and counting a light-receiving signal, which is converted by the light-emitting element based on either reflected light reflected from the object or transmitted light transmitted through the object, plurality of times in synchronism with a modulation frequency of the pulse-modulated light projected toward the object, so as to detect the object, wherein the modulation frequency of the pulse-modulated light projected toward the object is changed while carrying out the step of counting the light-receiving signal plurality of times. With this method, it is possible to prevent faulty operation when disturbance light or noise enters the light-receiving element without the light-receiving signal.

Abstract: There is provided an electronic security system for a perimeter structure that incorporates a fiber optic cable secured to the perimeter structure. Typically the perimeter structure is a fence. A light pulse is transmitted down the fiber optic cable. Mechanical attenuation devices disposed at various locations along the fiber optic cable are responsive to intrusion attempts. The mechanical attenuation devices produce measurable attenuations to the light pulse. Using backscattering light detection technology an intrusion attempt and the location of an intrusion is detected.

Abstract: A multi-optical-path photoelectric safety apparatus is provided that has a light emitting unit, a light receiving unit and a control unit for controlling each optical path. A light block substance sensing function for a multi-optical-path light curtain is also provided to sense an object between the light emitting unit and the light receiving unit. A muting area setting unit is also provided that can be taught how to set an area for exerting a muting function. The muting function can be provided only in a partial area of the light curtain by using the muting area setting unit.

Abstract: A vision system for a vehicle includes a light source generating an illumination beam, a receiver having a pixel array for capturing an image in response to at least a reflected portion of the illumination beam, the image corresponding to a first horizontal field of view (FOV) angle, and a controller coupled to the light source and the receiver. The controller receives a vehicle speed input and, in response, selects a portion of the image as a non-linear function of the vehicle speed to generate a second horizontal FOV angle for displaying to the vehicle operator. The displayed angular FOV decreases, non-linearly, as the vehicle speed increases.

Abstract: Under the present invention, a warning unit having a light source (e.g., a laser) is mounted on an emergency vehicle. The light source first emits a low intensity light beam (e.g., an infrared light beam) to scan an area in front of the emergency vehicle. The scan is used to detect one or more objects having a height to width ratio exceeding a predetermined threshold. Specifically, the scan is used to detect one or more tall, narrow objects such as poles, sign posts, etc., while ignoring other objects such as people, animals, etc. Once any applicable objects are detected, a second, higher intensity light beam is emitted to illuminate the detected objects with a predetermined indicia. The predetermined indicia can be observed by other motorists and indicates to them a direction of origin of the emergency vehicle.

Abstract: To provide an anti-thief security sensor assembly in which the angle of an optical unit can be adjusted over a wide range without increasing the size thereof and in which an optical axis can easily be adjusted, the security sensor assembly includes an optical unit (14) mounted at its lateral sides on a support member (9) of a device body (4) for rotation about a horizontal pivot axis (24) for projecting or receiving a detecting wave. A drive gear (29) is rotatably mounted on the support member (9) and positioned laterally of the optical unit (14) and adapted to be manually turned. A driven gear (39) is mounted on a lateral side of the optical unit (14) and is drivingly meshed with the drive gear (29). The driven gear (39) is rotatable together with the optical unit (14) about a horizontal pivot axis (11).

Abstract: In a multistage active infrared sensor, light emitters 11A, 11B, 11C emit infrared signals which contain distinct channel information. These light emitters 11A, 11B, 11C emit the infrared signals at different timings from each other. The sensor judges whether the infrared signals received by light receivers 12A, 12B, 12C contain channel information of opposite light emitters 11A, 11B, 11C. The sensor cancels any infrared signal which does not contain the channel information of the opposite light emitters 11A, 11B, 11C.

Abstract: An intrusion sensor which includes a first light guide arrangement and a second light guide arrangement for detecting the severity of an accident in a vehicle. An interval having a width is positioned between the two light guide arrangements. In this case, the first light guide arrangement is positioned in the direction of an intrusion side. The second light guide arrangement is positioned in the direction of the vehicle interior side.

Abstract: An apparatus for detection of any intruder passing through an electronic wall is disclosed. The electronic wall is formed by a millimeter-wave radar positioned at one end of the wall and a plurality of combinations of plane reflectors and retroreflectors placed along the floor of the wall as well as on structures at both ends. The wall is formed of a plurality of electromagnetic beams with each beam having two segments, one between the radar antenna and a plane reflector and the second segment between the plane reflector and a retroreflector. A sufficient number of beams inhabit the wall volume to make traversing the wall by an intruder without detection essentially impossible, even though the intruder should attempt such detection avoiding methods as crawling under or jumping over the assumed locations of the beams. The primary means of determining that an intruder is traversing the wall is the detection of one or more electromagnetic beams being partially or completely blocked.

Abstract: A small-sized hidden motion detector that can be incorporated in a decorative manner into a decorative lantern. The motion detector can be incorporated into lighting fixture designs not previously amenable to a hidden motion detector in the body of the lighting fixture. A small decorative motion detector housing is provided defining a compact interior region with a PIR sensor mounted inside and providing a sufficient optical pathway for a practical motion detector of wide angular field of view that can nevertheless fit inside commonly found small-sized decorative lantern elements. In one embodiment the motion detector is hidden in a small generally cylindrical decorative element of the sort that is found in a number of traditional decorative lantern designs and that has not previously been amenable to a hidden motion detector.

Abstract: To provide an intrusion detecting device capable of generating one of different warnings in proper timing dependent on the behavior of an intruder entering an alert region to thereby browbeat the intruder effectively, the intrusion detecting device (1) includes a plurality of sensor units (8 and 9), a sound generating device (29) capable of generating first and second warnings different from each other one at a time, and a warning generating unit (23). The sensor units (8 and 9) have a plurality of alert areas (A1 to A4) defined from a site distant from and to another site near to a subject to be monitored for security purpose and operable to detect an intruder H entering any of the alert areas (A1 to A4).

Abstract: A zone is monitored with an optoelectronic sensor. Light is transmitted in accordance with a structured light pattern in the direction of the monitored zone and is received from the monitored zone. The received light is converted into received signals and the received signals are evaluated with respect to the presence of an object, or with respect to a movement of an object, in the monitored zone. The light is transmitted and/or received in accordance with at least two different light patterns.

Abstract: An intrusion detector and method of operation which include a light source having a certain correlation length, and first and second light paths, wherein at least the first path extends through a secured area. A modulator, which is advantageously either a phase rotation modulator or path length modulator, is provided in the second path. At least one optical detector is placed to detect light traveling along the two paths. A comparator is electrically coupled to the detector to compare the detected signal with a signal applied to the modulator.

Abstract: An optical sensor includes a light transmitter for transmitting pulsed light signals and a light receiver for receiving them. In order to suppress the effects of interfering noise light, the light signals are transmitted according to a specified pattern including pulses in packages separated from each other by a specified interval, the pulses within each of the packages following one another with a specified carrier frequency. Groups each including two or more such pulse packages may be employed. The light receiver converts a received light signal into an electrical signal and directly thereafter passes the electrical signal through a bandpass filter with a pass band including this carrier frequency.

Abstract: Overlapping range rings from a pair of non-scanning radar or sonar transducers creates a grid structure within a surveillance area defined by their overlapping beam widths. Using PN coded transmission signals and doppler signal processing, intruder targets are detected, located, and tracked as they move throughout the grid structure. Intruders are identified by comparing their movement pattern to those of known intruders. Three dimensional surveillance areas can be monitored using three or more transducer sites.

Abstract: A passenger detection system is provided for a vehicle having at least one opening to allow passengers to enter and exit the vehicle. The passenger detection system includes a plurality of passenger detection devices placed on opposed sides of the at least one opening to detect passengers entering and exiting the vehicle through the at least one opening. The passenger detection system also includes a plurality of passenger number devices placed on at least one side of the at least one opening to detect the number of the passengers entering or exiting the vehicle through the at least one opening.

Abstract: An infrared detector includes a light emitter and a light receiver. The light emitter has plural light emitting units. A circuit connects the light emitter with a CPU programmed decoder and a power amplifying controller. A special coded signal is amplified and emitted out with an infrared light beam by the light emitting units to a light receiver. The light receiver has plural infrared light receiving units. A circuit connects the receiving units with a signal amplifier, a CPU programmed calculating and comparing decoder, and an output controller. The special coded signal with the infrared light beam received by each separate infrared light receiving unit is simultaneously sent to the signal amplifier for amplifying and to the CPU programmed calculating and comparing decoder for processing and controlled by the output controller. Thus, the infrared detector is prevented from being disabled by an unauthorized code or a different code by an unauthorized person.