Abstract: A multiple channel driver for fiber optic devices includes a source and an associated detector for each channel having processing circuitry and the power for the sources common to all channels. The system includes a master controller which has a precise time base to sequentially access each channel. The master controller is used to coordinate the multiple channels in a selected sequential manner. Synchronization of the channels avoids crosstalk since only one channel is on at a time. Power requirements are reduced since only one source is on at a time. The controller measures the background noise level, and subtracts it from the received signal. If the background noise level is too high, or the received signal too low, the master controller provides a warning. The controller also considers the signal history as an aid in locking onto signals and providing cleaner switching.

Abstract: A light intensity deterioration detecting circuit which includes a photodiode which receives light from a laser diode and having a cathode connected to a power supply and an anode connected to a first end of a resistor. A reference current source is connected between the power supply and a first input of a comparator which has the first input connected to a first end of a resistor and a second input connected to the first end of the resistor, and which compares a comparison voltage provided at the first end of the resistor and a comparison voltage provided at the second end of the resistor to output an output voltage on the basis of the comparison result. Errors of a resistance ratio are reduced to a negligible level if relatively large errors are produced in individual resistances, thus correctly detecting deterioration of a current to light output characteristic of the laser diode without an offset control.

Abstract: In an optical displacement sensor for measuring a moving state of a moving object by projecting a light beam onto a diffraction grating provided on a surface of a scale connected to the moving object and utilizing diffracted light beams of specific orders from among diffracted light beams diffracted by the diffraction grating, a portion of the light beams incident upon the diffraction grating is reflected at a reflecting region provided on the back of the scale a plurality of times. A photosensor detects a change in the amount of light emanating from a transparent or a light-blocking reference position, formed on a region on the surface of the scale other than the region where the diffraction grating is formed. An output signal from the photosensor is utilized as a reference signal, which provides information relating to the moving state of the moving object.

Abstract: A drive member of a peristaltic pumping mechanism includes a disk that rotates with the drive member and has two transparent sectors and two opaque sectors alternating with the transparent sectors. As a stepper motor rotates the drive member to pump fluid, a single optical sensor senses the disk and provides signals indicative of whether a transparent sector or opaque sector is being detected. A processor counts the number of motor steps in the detected transparent or opaque sector and based on the number of counted steps in a type of sector detected or the number of steps counted when a state change to the other type of sector occurs, determines the motor position. In another aspect, the position disk is integrally formed as a single piece with the cams and cam shaft of a pumping mechanism.

Abstract: A photoelectric switch includes a light emitting section emitting pulse light so that intensity of the emitted pulse light is sequentially increased. A light detecting section detects the pulse light emitted by the light emitting section. A light detection signal indicative of the received light is amplified and then integrated. A high-level light detection signal is delivered by the light detecting section when an integral value is equal to or above a threshold. A determination circuit delivers a first detection signal when a duration of the light detection signal is equal or above a predetermined values. The determination circuit further delivers a stable operation signal when a set time period is reached. The light detecting section is integrated into one-chip configuration.

Abstract: An active quench circuit for interrupting the current flow in an avalanche photodiode (APD) operating in Geiger mode and for resetting the APD. The invention increases the speed of quenching and reduces the time required to bring the APD voltage back to its operating voltage above the breakdown voltage. The circuit includes a small inductor which isolates the reset circuit from the APD during the initial discharge and which provides a current pulse into the APD immediately after the end of the quenching operation to recharge the diode. The reset circuit also includes a diode assembly that increases the speed of the avalanche current pulse and that prevents the circuit from oscillating or latching under certain operating conditions. The circuit presents a low impedance to the APD during during reset, and is much less sensitive to the APD capacitance than prior art circuits.

Abstract: A document reading apparatus includes a reference member used for determining the reference gray scale of an image on a document; a fluorescent lamp for illuminating the reference member; an image sensor for receiving light from the fluorescent lamp via the reference member and for converting the received light into an electric signal; a circuit for obtaining the difference between the latest data corresponding to a specified pixel among the output of the image sensor and the data before a predetermined period corresponding to the specified pixel among the output of the image sensor; and a circuit for determining whether or not the read operation of the document should be started by comparing the difference and a predetermined value.

Abstract: Optoelectronic device integrating a photodetector having two diodes arranged side by side, constructed from layers of semiconductor material on a substrate that also incorporates a light guide for directing light to the diodes. The two identical, juxtaposed diodes (D1, D2) are arranged head to tail. The diode ensuring the photodetection is that which is reverse biased.

Abstract: A solid state image converter has light-sensitive cells arranged in a matrix, each cell formed by two oppositely-connected diodes, at least one diode in each cell being a photodiode, and has driver circuits for driving the diodes, that are connected between the respective row and column lines of the driver circuits. The driver circuits electrically reset the diodes individually or row-by-row by clocking. By briefly forward biasing, the individual photodiodes so that they are briefly brought into the conductive state, and are subsequently reverse biased. The solid state image converter can be continuously exposed with x-rays and is employable in an x-ray diagnostics installation.

Abstract: A radiation source directs radiation toward a radiation sensor in such a way that the intensity of radiation sensed by the radiation sensor alternates in a periodic manner as the radiation source moves radially relative to the radiation sensor. The radiation sensor generates either a "1" or a "0" depending upon whether the intensity of the radiation sensed by the radiation sensor is above or below a particular reference value. Thus, the angular position of the radiation source relative to the radiation sensor is indicated by an alternating series of "1"s and "0"s. A multi-bit binary value which indicates the absolute position of the radiation source relative to the radiation sensor can be generated. In this case, a band of radiation is directed toward the radiation sensor. The radiation band is separated into a plurality of portions, the intensity of each successive portion being twice the frequency of the preceding portion. Each portion of the radiation band impinges upon a corresponding sensor.

Abstract: An active imaging system for viewing targets with a high degree of range resolution of approximately one foot. The imaging system utilizes a laser pulse which passes through an electro-optical pulse slicer which creates a sharp leading edge and/or a sharp falling edge on the laser pulse. The laser pulse travels to the target under observation, illuminates and reflects off of the target and returns to a camera. A target is viewed only during the time all or a portion of the returning laser pulse overlaps the time the camera shutter gate is open. The imaging system is particularly suited for determining depth information about a target by varying the time relationship when the returning laser pulse is received by the camera.

Abstract: An apparatus and a method are provided for measuring an ambient physical parameter applied to a highly birefringent sensing fiber. A light source emits a low coherence light beam into a sensing fiber subjected to an ambient physical parameter. A collector receives the output light beam of the sensing fiber and a splitter divides the output light beam into two orthogonally polarized output beams and subjects the two orthogonally polarized output beams to a range of relative delays. A recombiner combines the two orthogonally polarized output beams to produce an interference pattern, and a detector detects intensities of the interference pattern over the range of delays. A calculating device determines the ambient parameter from the intensities with improved accuracy.

Abstract: A system for sensing images using a detector array and correcting errors in the image signals caused by gain and offset variations from detector to detector in the array is disclosed. To correct gain and offset errors, the detector array is dithered by moving the detector line of sight between consecutive frames according to a predetermined pattern. This dithering causes different detectors to image the same location in the scene during different frames, and causes two adjacent detectors to scan between the same two points in the scene during a cycle of the dither pattern. Image data generated from the dithering is used to remove gain and offset errors from the sensed images, and to generate gain and offset correction values to be stored in a table and applied to the sensed images. The system is also adapted to compensate for scene changes when the detector array is installed on a moving platform.

Abstract: A distance sensor is provided for supplying a precise distance signal identifying the spacing between two components in a computed tomography apparatus which move relative to each other. The two components may be, for example, the rotating scan frame and the stationary gantry inside of which the scan frame rotates. The distance sensor includes a measuring mark mounted on one of the components and having a geometrical shape, such as the shape of a triangle tapering toward the other component, so that the measuring mark influences, such as by interrupting, the path of a measuring light ray which is emitted from the other of the components. The time during which the measuring mark influences the measuring light ray is dependent on the spacing of the components from each other.

Abstract: A satellite-borne system for the detection of near earth objects. The system periodically captures two images of the celestial sphere about the earth using a pair of linear arrays of optical detectors oriented so that the detectors image lines on the celestial sphere that are separated at each pixel in azimuth by the same angle. The position of the linear detectors is varied for each orbit of the earth by the satellite such that the entire celestial sphere can be imaged. The images produced by the two detector arrays are temporarily stored in memory until they can be processed using frame difference signal processing techniques. The results from the frame difference signal processing are transmitted to a ground station for further processing. The processing on the ground can include object classification, orbit tracking (using a time sequence of differenced frames), and earth collision determination and warning.

Abstract: An apparatus for converting a bipolar optical signal to a unipolar optical signal includes first and second photodetectors electrically coupled in series for receiving the bipolar optical signal. An electro-absorption modulator such as a self-linearized modulator, for example, is electrically coupled to the photodetectors. The modulator serves to transmit therethrough a portion of the power of an optical beam in an amount proportional to the power of the bipolar optical signal to form a transmitted beam. A constant current source is provided for supplying a current that shifts the power of the optical beam transmitted through the modulator by a predetermined amount, thus forming the desired unipolar optical signal.

Abstract: Pulsed infrared sensor including a solenoid to detect the presence of a person or object whereupon the solenoid is activated to regulate fluid flow, including a microprocessor for receiving inputs from a plurality of sources and to provide outputs to a plurality of receivers for the control of the fluid flow, and a collection of inputs receivable by the microprocessor from sources activated in response to infrared rays received after transmission from an infrared transmitter including a remote transmitter associated with the microprocessor to activate a fluid supply control to control the supply of fluid to the fixture.

Abstract: An optical disk drive which does not require a high precision servo mechanism and intensive error correction technique. The recording surface of a recording medium is stationary and is completed as a spherical or semi-spherical plane. An optical head is provided at the center of curvature. A laser beam emitted from the optical head, provided at the center of curvature, is displaced physically or electrically, without rotating the recording surface.

Abstract: An X-ray image intensifier has a vacuum envelope consisting of glass, and an input window consisting of aluminum and having a sectional meridian radius of curvature which increases from the central portion of the input window to the peripheral portion thereof is arranged on the input side of the vacuum envelope with a metal holding ring and a Kovar ring. An input phosphor surface is arranged adjacent to the inner surface side of the input window, and an X-ray image incident through the input window is converted into a photoelectron image. In order to minimize an influence caused by scattering of X-rays or .gamma.-rays incident through the input window, an input substrate is brought as close to the input window as possible. A coaxial cylindrical focusing electrode and an annular focusing electrode are arranged on the side wall in the vacuum envelope, and an anode is arranged on an output end side.

Abstract: A soft x-ray imaging device is disclosed having a housing defining a housing chamber. A faceplate having a planar surface is secured to the housing so that the planar surface is positioned within the housing chamber. A phosphorus coating is applied to the planar surface of the faceplate for convening electrons to visible light. A microchannel plate for convening x-rays to electrons is secured within the housing chamber so that the microchannel plate is spaced from and parallel to the planar surface of the faceplate. An opening is formed in the housing in alignment with the microchannel plate and this opening is sealingly closed by a window which is made of a material substantially transparent to soft x-rays. This window also creates a vacuum tight housing chamber which is continuously evacuated by a pump.