Abstract: A light source is energized by pulses controlled by a frequency standard taken from a resonant circuit output. The resonant circuit acts as a narrow-band filter and comprises the capacitance of a photoresponsive receiver and an associated inductor so that a desired filter frequency is obtained. The accurate coincidence of the light source pulse frequency and the resonant circuit acting as a narrow-band output filter permits optical interference acting on the measuring apparatus to be effectively suppressed.

Abstract: A photoelectric switching apparatus includes a light transmitter part having a first built in oscillator and a detachable light transmitter circuit driven by the first oscillator. A detachable light emitter is provided for emitting light in response to a signal from the light transmitter circuit. A light receiver part includes a photoelectric transducer for converting a light signal incident thereon to a converted electric signal and a second oscillator which is separate from the light transmitter part and can be connected to the light transmitter circuit when the light transmitter circuit and the light emitter together are detached from the first oscillator. The light receiver part has a D-flip-flop which reads input data based on the converted electric signal by utilizing an output signal of the first oscillator as its clock pulse.

Abstract: The active automatic focusing apparatus disclosed scans the object to be photographed with light from a light projector and includes a sensor sensing reflected light, a peak detector for detecting the peak value of the signal sensed by the sensor, a control producing a stop signal suitable for stopping focusing movement of the objective lens in accordance with the output of the peak detector, and a stop device for stopping the movement of the objective lens on the basis of the output of the control. A comparator compares the level of the detected signal with that of a preset noise signal so as to produce a first control signal when the level of the detected signal is higher than that of the noise signal. A given distance detector produces a second control signal when the objective lens is moved to a predetermined position corresponding to a distance at which a peak of the detected signal can be detected by the peak detector.

Abstract: A position measuring system comprising a transmitter (5, 19) mounted on one body and arranged to direct a flashing beam of radiation onto an area sensor (11) which is mounted on the other body and forms part of a receiver arranged to produce an output indicative of the position of impingement of the beam on the sensor from samples of the radiation impinging on the sensor when the beam is on and off, the receiver including a second sensor (31) responsive to the radiation beam whose output synchronizes the operation of the receiver to the flashing beam. The requirement for a physical connection between receiver and transmitter to synchronize the receiver with the flashing beam is thereby avoided.

Abstract: A photodetector device for photoelectrically detecting the presence of a moving body, comprising an operational amplifier receiving as a first input an electric signal which is in proportion to variations in the quantity of light, and a delay circuit for delaying the electric signal by a predetermined period of time and applying the electric signal to the operational amplifier as a reference input with respect to the first input. The information of the presence of a moving body is obtained as an output from the operational amplifier.

Abstract: A photoelectronic apparatus, in which a photoelectric convertor (the operational convertor) receives a beam of light and produces an output signal proportional to the intensity of the light received, is protected against the effects of unwanted light by providing an auxiliary photoelectric convertor arranged in the vicinity of the operational convertor. The auxiliary convertor detects the presence of unwanted light and its output is subtracted from that of the operational convertor and the resultant signal is then examined to distinguish between events occuring in the light beam and events simulated by the unwanted light.

Abstract: An adaptive gain integrator circuit is provided having a first integrator for producing an output which is proportional to the ambient light noise level and the amplitude of the laser illumination signals applied thereto. A second feedback circuit having a noise-only integrator is provided to maintain the noise level applied to the first integrator substantially constant despite wide variations in the amplitudes of ambient light detected by the system, thereby to reduce the false alarm rate and increase the sensitivity of the system.

Abstract: A photoelectric beam system for the detection of the arrival of an object at a discrete station wherein artificial light, natural light, or no light may be present. A signal generator turns on and off a signal light at a selected frequency. When the object in question arrives on station, ambient light is blocked by the object, and the light from the signal light is reflected onto a photoelectric sensor which has a delayed electrical output but is of the frequency of the signal light. Outputs from both the signal source and the photoelectric sensor are fed to inputs of an exclusively OR detector which provides as an output the difference between them. The difference signal is a small width pulse occurring at the frequency of the signal source. By filter means, this signal is distinguished from those responsive to sunlight, darkness, or 120 Hz artificial light. In this fashion, the presence of an object is positively established.

Abstract: An optical sensor device for use in optical instruments is disclosed. The optical sensor device is provided with an optical sensing region having at least one sensor element responsive to incident light for producing a charge, first and second charge storing regions each having the same number of charge storage elements as that of said sensor elements for accumulating the charges produced from said sensor elements, a first gate region for controlling the transfer of charge from said optical sensing region to said first charge storing region, and a second gate region for controlling the transfer of charges from the optical sensing region to the second charge storing region. Upon alternate application of a voltage to said first and second gate regions, the charges produced from said optical sensing region are alternately accumulated on said first and second charge storing regions.

Abstract: An active optical target detecting device is provided for a missile. A transmitter radiates within the optical spectrum. This radiation is subject to scattering by water droplets in the atmosphere which may be due to clouds, fog, rain or other adverse weather conditions. In order to improve the signal-to-noise ratio two receivers that are associated with each transmitter are angularly displaced by equal angles from the transmitter. Hence, each receiver receives only one half of the undesirable backscatter radiation. Therefore, the target may be more readily detected even in the presence of backscatter.

Abstract: A detector for detecting radiation from a Q-switched laser. The detector prises a plurality of silicon photo-diodes (10) which develop an output signal when struck by incident radiation from the Q-switched laser. The output of the photo-diodes is connected to a pulse-width discriminator (12) and a pulse-amplitude discriminator (13). The pulse-width discriminator generates an output signal only if the amplitude of the output pulse from the photo-diodes is less than 300 nanoseconds, signifying an input pulse from a Q-switched laser. The pulse-amplitude discriminator develops an output signal only when the photo-diode is saturated, again, indicating radiation from a Q-switched laser. The presence of a signal from either the pulse-width discriminator or the pulse-amplitude discriminator indicates that the incident radiation on the photo-diode was indeed from a Q-switched laser.

Abstract: A distance measuring device is disclosed. This device has light projecting means. Light is projected from this projecting means to a target, and the concurrently reflected light from the target is received by photoelectric light receiving means which is provided with a plurality of photosensitive elements independent of each other and arranged in such predetermined distances from the above described light projecting means as to correspond to individual object distances different from each other. From the concurrent state of output of said photoelectric light receiving means there can be detected a distance to the above described target.

Abstract: A dynamic level shifter for photoelectric touch panels incorporating a plurality of photoelectric transducers periodically senses the ambient light level, immediately before the interval when each transducer can receive a pulse of radiant energy during normal operation of the panel. The output of the phototransducer during the such interval is compared with the output during the previous ambient interval, to develop a signal indicative of the presence or absence of the pulse, irrespective of ambient light fluctuations.

Abstract: A first photodetector arrangement comprises three adjoining photodetectors, and a second comprises six. First and second optics, and the two photodetector arrangements, are located immovable on the camera, and the optics project onto the first arrangement an image of a subject which is to form the basis of a subject-distance measurement, without shift between image and photodetectors of the first arrangement so long as the subject-distance is within one of the ranges the system is to furnish; whereas the image projected onto the second photodetector arrangement shifts relative thereto in dependence upon the distance to the subject. The six photodetectors of the second arrangement are subdivided, for signal-processing purposes, into four successive groups, respectively comprised of the first, second and third photodetector, the second, third and fourth, the third, fourth and fifth, etc.

Abstract: 1.

Abstract: A system for optically detecting the presence of indicating markers on microfilm frames and for ignoring stray marks and smudges. As light shines through the microfilm and is detected by a photo-transistor, the system self regulates to provide an absolute baseline value, called a prescaler, for each frame of microfilm. Then, as each mark appears on the microfilm and interrupts the light path to the photo-transistor, the degree or extent of light blockage is measured as a deviation from the baseline for that frame. If the deviation exceeds a predetermined threshold, the mark is counted as a marker; otherwise the mark is ignored as a stray spot or smudge. The threshold is also self regulated based on a percentage of the amount that the light blockage of the marker in the immediately preceding frame deviated from the baseline for that frame.

Abstract: A system for warning a target designator operator whenever a target less n a predetermined distance from the operator is designated. Actuating the target designator triggers a time interval counter and circuitry to detect reflected pulses. An indicator will warn the operator if a pulse is reflected to the system from an object less than a predetermined distance from the operator.

Abstract: A seed sensor detects seeds passing through a chute or housing forming a path of travel for seeds dispensed from a seed planter. A source of light such as a light emitting diode is optically exposed to the path of travel and a photosensitive element such as one or more photoresponsive transistors is optically exposed to the path of travel for receiving the light from the light source. An electronic circuit is connected with the photosensitive element for producing an electrical signal responsive to the light level incident thereupon and producing a change in the electrical signal in response to a momentary change in light level due to the passage of a seed. The electronic circuit includes a circuit element such as a diode connected with the photosensitive element for maintaining at least a given amount of change in the electrical signal output level in response to a given change of light level corresponding to passage of a seed.

Abstract: A method for masking on the display device associated with a thermal telescope for the night guidance of self-propelled missiles carrying an infrared source, the image of a source of relatively intense stray radiations, wherein, on the one hand, the radiations transmitted in the field of vision of the thermal telescope are simultaneously detected in two different spectral bands, of which the one, called the useful band, corresponds to the maximum radiations from the target and the surrounding landscape, and the other one, called stray band, corresponds to the maximum radiations from the intense infrared sources carried or not by the missile, and on the other hand the signal detected in the first band is corrected by the signal detected in the second band in a manner to leave out the stray portions of the useful signal.

Abstract: A highway line detection system for an automobile which provides an output signal when a traffic line on a pavement under an automobile is about to be crossed. It includes a photoelectric sensor connected to an electrical bridge circuit, and the bridge circuit includes an impedance element which is varied in impedance responsive to the integrated output of the bridge circuit, and thereby the bridge circuit is maintained in balance for ambient light conditions. Further, the threshold of detection of the system, at which point an alarm is sounded, is varied as a function of the ambient light state, whereby the sensitivity of the system is increased for low light conditions and decreased for high light conditions to compensate for an opposite characteristic of the photosensor.

Abstract: An automatic ambient light compensating circuit for use in conjunction with a light sensing device to render the light sensing device insensitive to variations in ambient light conditions and which is particularly adapted for use with reflective sensor systems. An optical sensor, including a source of light and a first photodetector, is disposed to detect the presence of an object in proximity thereto. The optical sensor provides an output signal which is a function of the amount of light received by the first photodetector and includes light from the source of light and ambient light. The output signal of the optical sensor is provided as an input to a signal level detection means. A second photodetector responsive only to ambient light is operatively connected in parallel with the output of the optical sensor to the level detection means to compensate the output signal of the optical sensor for ambient light conditions.

Abstract: An arrangement which enables the presence in an observed field of a light source whose radiation spectrum is known to be detected with a high signal to noise ratio. It includes an acousto-optical tunable filter controlled to scan through the expected spectrum of the source periodically and preferably linearly. The photo-detected signals are processed by a high-pass filter which removes the D.C. component due to ambient interference radiation and provides a periodic signal which correspond to the observed light source. The arrangement applies, in particular, to the angular location of luminous targets.

Abstract: The present invention comprises an improvement in programmable phonograph record players which provide automatic sound track selection of the recorded portions of a record. The improvements comprise the provision of an optical scanner mounted on the tone arm including an incandescent light source for directing visible light onto the record surface and a photodetector for receiving light reflected by the record surface. In an alternate embodiment, a differential sensor system includes a light emitting diode and a pair of photodetectors for detecting the presence of a highly reflective, unrecorded land area between two successive recorded sound track portions of the record. In another embodiment, the scanner includes a pair of alternately illuminated light emitting diodes and a single photodetector for receiving the light energy, directed by the light emitting diodes onto the record surface, reflected toward the photodetector.

Abstract: A beam-of-light (BOL) sensor having means for regulating the intensity of the sensor light source to compensate for extraneous factors in its operating environment, e.g., dust accumulation, component aging, misalignment, etc., that may affect consistent sensor operation. The BOL sensor includes a photosensor whose output signal is compared against a reference signal to determine if the light source intensity is of the proper level. The comparison signal is used to gate clock pulses to a counter to adjust its stored count upward or downward, dependent on whether the light source intensity is low or high, respectively. A filter is provided to override interruptions in the photosensor output signal below a predetermined minimum time duration.

Abstract: A beam-of-light (BOL) sensor having means for regulating the intensity of the sensor light source to compensate for extraneous factors in the operating environment, e.g. dust accumulation, that may affect consistent sensor operation. The BOL sensor includes a photosensor whose output signal is compared against a reference signal to determine if the light source intensity is of the proper level. The comparison signal is transformed into a digital pulse that adjusts the stored count of a counter upward or downward in accordance with the comparison of the photosensor signal and reference signal. The adjusted count is converted to analog form and fed back to drive the light source.A trailing edge detector enables the counter to count up or down when an object is in the sensing station defined by the light source and photosensor.

Abstract: A programmable phonograph record changer which provides automatic sound track selection for each of a plurality of records played sequentially by the record changer. The record changer includes an electro-optic scanner mounted on the pickup arm for sensing the land areas located between the various sound tracks of a disc-type record. An auxiliary tone arm lift and sweep mechanism is controlled by a digital logic system connected to the electro-optic scanner to drive the tone arm across various bands which the user does not want to be reproduced. The logic system includes a programmable memory which stores the preselected sound tracks of a sequence of records which the user intends to be reproduced. A land sensing circuit includes a means for developing a threshold signal which varies with the record surface reflectivity characteristics.

Abstract: A light activated load switch for applying electrical power to load when its triggering light sensor is struck by a light source and including photosensing means to protect against triggering by inadvertent, ambient of unwanted light sources. The device includes adjustable timing means for automatic turnoff loads and for double triggering modes of operation.

Abstract: An apparatus for testing the optical output of light-emitting devices in the presence of ambient light, with means for compensating for said ambient light, is described. The d.c. and periodic components of the ambient light are measured and stored during a time when the apparatus is not being subjected to radiation from the device under test (DUT). When radiation from the DUT is received, the resulting signal is processed with the stored ambient light intensity data, and an output proportional to the intensity of the radiation from the DUT and compensated for the ambient light is provided.

Abstract: A detector for marks having a color which contrasts with the mark background employs a solid state light source projecting a light beam having a plurality of wave length components corresponding to a plurality of colored light wave lengths. The light beam may approach the appearance of white light. A pulse modulated detector or sensor is used for receiving light reflected from colored surfaces having contrasting colored marks thereon, wherein high ambient light level rejection is obtained and high signal to noise ratio is provided in a sensor output. The sensor output is gated to eliminate between pulse noise, and the gated output is integrated to obtain a reference signal to which the gated pulse is continuously compared. An increase or decrease in signal is used to provide a light or dark mark indication respectively as a result of the comparison. Feedback from the output suppresses signal instability which may exist at the edges of the detection threshold.

Abstract: A photometric monitoring device for detection and surveillance of objects entering and leaving a light field is provided wherein a monitored light source is compared with a reference light source in such a manner that abrupt or rapid changes in monitored light are detected and gradual changes are ignored. A first photo cell for monitoring a light source is coupled to the input of an operational amplifier having a feedback loop which includes a reference light source coupled to a second photocell. An RC network delays the reaction of the operational amplifier in balancing the voltage across both of said first and second photocells when abrupt changes occur, allowing a signal to be developed. Additional circuitry includes a comparator responsive to such developed signals which exceed predetermined limits, producing an output signal for use by a utilization device, such as a camera, recording device, alarm system, or the like.

Abstract: Detection device for detecting movements by means of a source of light and a photo-detector, which device is provided with: (1) a pulse generator for supplying the source of light with a proportionally very large amount of energy during a very small part of the time; and (2) with a comparator, synchronized with the pulse generator, for comparing a signal received from the photo-detector with the preceding signal during the said time and for delivering a signal to a counter in case a difference is ascertained. The device can be utilized in a manual sorting device comprising one or more sorting-cases. Movements of the upper surface of the stack in a pigeon-hole can be detected by means of reflection. The detection devices in the pigeon-holes are connected via multiplexers and demultiplexers to a central processing unit that has been provided.

Abstract: A device is provided for controlling the sensitivity of a receiver of the type comprising a photosensitive element operative to convert radiant energy into electric signals and having an amplifier connected to the output of the photosensitive element and signal processing members for separating a useful signal from interfering background radiation. A sensor device is connected to the photosensitive element to sense the direct current which the element emits in response to radiation from the sun or other strong sources of disturbance, the sensor device being operative to emit a signal when the direct current exceeds a predetermined value, and a switching device responsive to said signal operates to switch the amplifier from a given fixed sensitivity level to a lower fixed level of sensitivity.

Abstract: A vehicle guidance mechanism for guiding a vehicle along a guide line comprises a radiation source that causes the guide line to reflect or emit a guidance signal; photocell sensors mounted in the vehicle and adapted to sense the guidance signal and produce an error output signal proportional to the variation of vehicle position from a predetermined lateral position with respect to the guide line; and a control device in the vehicle adapted to steer the vehicle in response to the error signal so as to cause the vehicle to follow the guide line. An automatic contrast or gain control circuit eliminates the effect of background illumination in the output signal received from the guide line. Modulation circuitry and appropriate filters reduce the effects of static background illumination and improve the reliability and line detecting ability of the guide system. Line detection circuitry is employed to prevent operation of the automatic control device unless the vehicle is tracking a valid guide line.