Abstract: A motion picture signal, as it is obtained from a camera, is processed by a spatiotemporal filter so that an optical flow of a concerned object is measured, and a velocity of the object is measured from the optical flow, identifying the object.

Abstract: A backstop or target particularly suited for use in athletic applications such as baseball or golf, and which includes a frame from which a flexible net is suspended at its corners and connected to a plurality of linear displacement sensors. As the net is displaced due to the impact of a projectile such as a ball, tension is applied to the cords which in turn move the axially-moveable components of each linear displacement sensor. In one embodiment, the linear displacement sensors utilize a light beam and photoelectric detector to plot the time intervals at which equally-spaced indices on the axially-moveable component pass a predetermined point. This data is used to determine position, velocity, or trajectory of the projectile relative to the initial plane of the net using direct geometric and trigonometric calculations.

Abstract: In a laser radar (lidar) system, a Doublet Pulse is generated by injection-seeded aborted cavity dumping of a solid-state laser. The doublet pulse provides coherent Doppler lidar systems a substantial time bandwidth product (TB) with a very modest processing requirement. The waveform format comprises a pair of pulselets, each of duration .tau., separated by T seconds. The range resolution is governed by the pulselet duration .tau., while the velocity precision is governed by one over the pulselet separation, T. Ambiguities in the velocity measurement arise as a result of the periodic structure of the waveform and occur every .lambda./2T m/sec, where .lambda. is the operating wavelength. These ambiguities are removed by conventional de-aliasing algorithms as well as through the generation and processing of higher order pulse waveforms.

Abstract: A process and apparatus are disclosed for generating object traces representing the movement of objects through a measuring space. The measuring space can be illuminated by a laser or other light source, or alternatively the objects can be self-illuminating. In either event, light from the objects is detected over a finite acquisition time, to generate the object traces. During a predetermined portion of the acquisition time, preferably near the end, one of several parameters that govern the object trace width is altered to increase the width, thereby giving the object trace the form of an arrow or vector. The altered parameter can be the brightness of illumination, the sensitivity of the image detector, or the position or state of system components, in particular the image detector, a lens or other active optical component between the objects and the detector, or an optical component between the light source and the objects.

Abstract: Apparatus for obtaining the speed and acceleration of a motor vehicle in which the speed and acceleration are used in combination with exhaust emissions data obtained from the motor vehicle to analyze information about the pollutants being dispersed into the air by the motor vehicle. The apparatus includes a first radiation source producing a visible laser beam received by a first detector and a second radiation source producing a visible laser beam received by a second detector. The first and second radiation sources are arranged along the roadway with a known spacing and at a height so that the visible laser beams are interrupted by the front and rear wheels of the motor vehicle as it passes along the roadway. The detectors provide output pulses indicating whether the visible laser beams are interrupted and the time of the occurrence of each of the pulses is measured and recorded. An analyzer then calculates the speed and acceleration from the known spacing distance and the stored time measurements.

Abstract: Novel rotation sensors are disclosed, sensors with a temporal resolution of one measurement per rotation. A transparent or absorbing substrate can be coated with a transparent thin film to produce a linear response in reflectance versus angle of incidence over a certain range of angles. The best results were obtained when the incident light was s-polarized. For example, a Si substrate coated with an SiO.sub.2 film was used in constructing a reflection rotation sensor. Experimental results and an error analysis of this rotation sensor are presented.

Abstract: Substantial improvements in photorefractive device lifetimes are provided by control of electron migration which results in the decay of gratings in photorefractive materials due to diffusion and other effects. A new class of photorefractive devices using compensating electronic and ionic gratings having relatively low efficiency but nonetheless usable gratings is provided by arranging the gratings to be reflective in a wavelength band outside the photo-excitation band of the photorefractive material, as by using an infrared operating wavelength. Longer lifetimes in high efficiency gratings are achieved by constant or periodic illumination of photorefractive materials to assure uniform charged distribution of electrons and maintenance of the ionic backbone grating.

Abstract: An apparatus for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle's size can be determined from the intensity of the light scattered. The particle's velocity can be determined from the elapsed time between various intensities of the light scattered.

Abstract: A laser transponder and method for disabling a laser-based speed monitor of the type that transmits a monitor laser beam at a moving motor vehicle. The monitor laser beam transmitted by the speed monitor is detected when it arrives at the motor vehicle. In response to detecting the monitor laser beam, a warning is output to the motor vehicle driver and a jamming laser beam is transmitted toward the speed monitor. The jamming laser beam includes a plurality of pulses separated from each other by a time period that is less than or equal to an amount of time needed for the monitor laser beam to travel from the speed monitor to the motor vehicle and back to the speed monitor. The jamming laser beam disables the speed monitor for a time period sufficient to allow the motor vehicle driver to reduce the speed of the motor vehicle.

Abstract: A disabling system for disabling a laser-based speed monitor of the type that transmits a monitor laser beam at a moving motor vehicle. The monitor laser beam transmitted by the speed monitor is detected when it arrives at the motor vehicle. In response to detecting the monitor laser beam, a warning is output by an annunciator to the motor vehicle driver and a jamming laser beam is transmitted toward the speed monitor. The jamming laser beam disables the speed monitor for a time period sufficient to allow the motor vehicle driver to reduce the speed of the motor vehicle. The jamming laser beam is transmitted by a laser transponder structured to be powered only by the vehicle battery. Plural laser transponders are coupled to a single annunciator to provide plural points of speed monitor detection and jamming without requiring plural annunciators.

Abstract: A system for measuring the quality of pavement surfaces. An amplitude modulated laser scanning system, mounted on a motor vehicle, scans the pavement surface as the motor vehicle travels over it. A detector detects the laser beam reflection from the surface and a phase measuring device counts pulses to digitally determine the phase shift in the reflected laser beam in order to calculate the profile of the surface. The profile information is used to determine various quality features of the pavement surface.

Abstract: Compensation is performed to eliminate noise generated by fluctuation of a medium that surrounds an object to be measured. First and second laser beams having different wavelengths are generated by a He--Ne laser and a YAG laser, respectively, and are superposed by a first dichroic mirror such that they propagate along a common path. The first laser beam is caused to reflect off the object to be measured, while the second laser beam is reflected by a second dichroic mirror before reaching the object. The first and second reflected laser beams are separated from each other by a third dichroic mirror. The reflected first laser beam is detected by a first position sensor, while the reflected second laser beam is detected by a second position sensor. This makes it possible to compensate for noise generated by fluctuation of the medium around the object to be measured, so that the object can be measured accurately and reliably.

Abstract: An apparatus for detecting the displacement information of an object to be measured has a light source, an electro-optical crystal disposed at the incidence position of a light beam from the light source, the light beam being modulated in the electro-optical crystal, the light beam being internally reflected at least once in the electro-optical crystal and emerging therefrom, and a light receiving element for receiving the light from the object to be measured to which the light beam having emerged from the electro-optical crystal is applied, the displacement information of the object to be measured being detected by the light reception of the light receiving element.

Abstract: A laser transponder for disabling a laser-based speed monitor of the type that transmits a monitor laser beam at a moving motor vehicle. In response to detecting the monitor laser beam, a warning is output to the motor vehicle driver and a jamming laser beam is transmitted toward the speed monitor. The jamming laser beam disables the speed monitor for a time period sufficient to allow the motor vehicle driver to reduce the speed of the motor vehicle. The laser transponder includes a housing that acts as both a heat sink for the laser transmitter in the laser transponder and a structural package that is waterproof and sufficiently rugged to be positioned on the outside of the motor vehicle. The laser transponder is securely attached to the motor vehicle by a connection system that enables a user to adjust the angular orientation of the laser transponder as necessary to detect the monitor laser beam and transmit the jamming laser beam to the speed monitor.

Abstract: In the optical measurement of the flow vectors in gas flows, two substantially parallel light beams (11a, 11b) are focussed at separate focussing spots. The particles passing the focussing spots light up and thereby generate a start pulse and a stop pulse, respectively. Therewith, the component of the flow vector extending in the normal plane to the optical axis (OA) is detected by transit time measurement. The flow component pointing in the direction of the optical axis (OA) is detected independent thereof according to the Doppler principle by supplying the scattered light generated by the particles to an optical frequency/amplitude converter (22).

Abstract: An optical velocity measuring device includes a pair of V/H sensors effectively located at two different distances from a moving object. Each sensor is used to determine an image velocity and a corresponding angular velocity of the object. The angular velocity measurements and the difference in distance or optical path length of the individual sensors are used to determine the absolute linear tangential speed of the object without determining the absolute distance to the object.

Abstract: The present invention relates to apparatus and methods for the precision measurement and calibration of a body such as a precision rotary table. It consists of at least one, or preferably a polygon of mirrors placed on the body or around a circumference of the precision rotating table and an interferometer instrumentation arranged on an optical path which includes the mirrors. The rotational angle of the body or table is continuously measured with high accuracy without being affected by bearing runout. An optical means for detecting actual positions of the body using a laser and razor blade means provides for simple and easy calibration of the body's position.

Abstract: A countermeasure-detecting circuit, and associated method, for a laser speed detector. Countermeasures taken at a moving target, such as a vehicle, to interfere with operation of the laser speed detector are detected. When countermeasures taken at the moving target are detected, the sensitivity of the laser speed detector is altered to overcome the effects of the countermeasures.

Abstract: A method and apparatus for measuring the velocity of a gas flow that does not require the seeding of the flow is disclosed. The method and apparatus produce a population of stable molecules within the flow. This population of stable molecules is produced within the flow at a first time point. A population of excited molecules is produced from the stable molecules at a second time point by exciting the stable molecules with a laser beam. This laser beam also induces fluorescence in the population of excited chemical species at the second time point. Typically, the interval between the first and second time points is known and the velocity of the flow is calculated by dividing the distance travelled by the stable molecules in the flow by the known time interval. The preferred example of the stable molecule is ozone. Oxygen molecules are fluoresced by a 193 nm laser beam at a first time point, producing oxygen atoms.

Abstract: A simplified mechanism for rotationally aligning and gapping a pattern wheel with respect to a stationary mask are provided as part of a modular optical shaft encoder in accordance with the present invention. Moreover, the present invention includes a simplified method of connecting and aligning a modular encoder to a shaft. A radial alignment mechanism is provided between engagement surfaces of the hub of the pattern wheel and the encoder housing for independently providing radial alignment. The engagement surfaces are designed so that as the surfaces are urged into engagement with one another, the encoder housing (and thus the mask pattern) becomes radially aligned to the pattern wheel (and specifically its pattern). As an independent functional mechanism, a linear cam member is utilized for gapping the hub of the pattern wheel and thus the pattern thereon to the stationary mask pattern.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: Transceiver head for a longitudinal Doppler speed indicator.Transceiver head for a longitudinal Doppler speed indicator with at least one pair of measuring axes.It comprises:a laser (1);polarization switching means (4) on the path of the laser beam;polarization separating means (5) on the path of the polarized beam that comes from the switching means;control means (5) for switching the switching means alternately from one state to another to direct the beam alternately to one measuring axis and then to another depending on its polarization state.

Abstract: In keeping with one aspect of this invention, apparatus for measuring the flow of gas in a pipeline includes an optical transmitter, an optical receiver and a processor. The apparatus measures the flow of gas through a generally cylindrical gas pipeline, engine intake or the like. The transmitter includes a laser diode array and a collimator lens which are preferably located outside of the pipeline, or in the wall of the pipeline. The transmitter generates multiple, spaced, discrete laser spots in the pipeline. Particles in the gas scatter the light as they pass through it, and the scattered light is received by another collimator lens and photodetector, which are also preferably outside of or in the wall of the pipeline. The output of the photodetector is processed by a computer which calculates the velocity of the particles and hence the flow rate of the gas.

Abstract: A scanning type exposure apparatus includes a mask stage which can move a mask along a predetermined scanning direction; a substrate stage which can move a substrate, onto which a pattern on the mask is to be transferred, along the scanning direction; a fine movement stage which is arranged on one of the mask stage and the substrate stage, and is movable along the scanning direction relative to the one stage; a first measuring device for detecting the position, along the scanning direction, of the fine movement stage; a second measuring device for detecting the position, along the scanning direction, of the other one of the mask stage and the substrate stage; a speed controller for controlling the ratio between the speeds of the mask stage and the substrate stage to a predetermined value while the pattern on the mask is scanning-exposed on the substrate; and a control device for controlling the position of the fine movement stage in accordance with the difference between the position measured by the first mea

Abstract: A sensor system including a first layer having first and second surfaces and a first index of refraction, a second layer having a second index of refraction which is less than the first index of refraction, a mechanism for generating a first diffuse light beam which passes through the first layer from the first surface to the second surface, and a mechanism for sensing a portion of the first diffuse light beam reflected back through the first layer to the first surface as an incident of the first diffuse light beam impinging upon the second layer.

Abstract: The test range is provided with a calibration system for calibrating the exact position of a light curtain formed by a ballistic screen. The calibration system uses a model ball which can be moved through a light screen at high speed in order to simulate the actual passage of a driven golf ball through the light screen. Positioning of the model golf ball at a point at which the golf ball just contacts the light screen serves to determine the exact location of the light screen. A laser ranging device is used to locate the calibration system relative to a launch point. Thus, the precise distance of the curtain of light from the launch point can be readily determined. The calibration system may also be used to determine if a ballistic screen is mounted in a true vertical plane.

Abstract: Applicant's invention is a method and apparatus for inhibiting laser detection wherein the infrared laser light from a laser gun is absorbed, diffused, and dispersed, hindering the quick response needed for accurate laser readings. The laser detection inhibitor incorporates a rectangular thermoplastic lens panel and a filtering treatment which coats or is infused into the thermoplastic lens panel. The thermoplastic lens panel is suitably formed for placement over a vehicular license plate. The panel is adapted for placement over the license plate. After the panel is sprayed or infused during molding with the filtering treatment, the panel is affixed over the license plate using the existing attachment means for the vehicular license plate. Applicant's invention may also be placed in spray or film form over other reflective vehicular parts. Applicant's invention uniformly covers the license plate absorbing, diffusing, and dispersing infrared laser light and therefore, inhibiting laser detection.

Abstract: A device for determining the velocity of a longitudinally traveling textile material, especially a yarn, using the closed-loop correlation of a transit time correlator in such a way that its reliability is improved. At least one sensor g.sub.1 consists of two signal receivers disposed one behind the other in the running direction of the yarn, having a sensor output characteristic curve with the intersection of the abscissa in the effective sensor center axis, and wherein the output characteristic curve shows a point-symmetrical behavior at least in the vicinity of the intersection with the abscissa. A second sensor g.sub.2 has a steady state output characteristic curve in the area of its effective sensor center axis. The control loop circuit of the transit time correlator is designed such that the undifferentiated cross-correlation function is used as the controller input signal for determining and readjusting the adjustment point for the model delay time .tau..

Abstract: A method and apparatus for determining the rate of angular rotation of a rotating object comprising directing a beam of substantially coherent electromagnetic radiation towards the rotating object (80); detecting speckles generated by electromagnetic radiation (60) scattered from the object; and determining the transit time of the detected speckles; wherein the field of electromagnetic radiation (60) scattered from the object is Fourier-transformed by an optical Fourier-transforming system (20); and subjective speckles (71) of the Fourier-transformed electromagnetic radiation (70) are detected in at least two detection regions (12, 13) positioned in a detector plan (9) substantially parallel with and located in or near the Fourier-plane (10) of the Fourier-transforming system (20).

Abstract: A method for measuring the flow rate of a liquid, particularly of blood, in which the frequency shift of a laser beam reflected from the liquid is determined according to the optical Doppler effect. This method and the apparatus provided for its implementation are designed so as to enable reliable measurement of the flow rate of the flowing medium which is resolved both spatially and with respect to time. In accordance with the invention at each scanning point a number of N measured values is collected corresponding to the reflected light, N being a whole number equal to or larger than 2; the Doppler shift is calculated from the time variation of the thus measured intensity of the reflected light at the respective scanning points, and the flow rate is determined from the Doppler shift at each point of the scanning pattern.

Abstract: A closed-form integration method is derived and analyzed for computing motion trajectories from velocity field data, in particular as measured by phase contrast cine (PC) MR imaging. By modeling periodic motion as composed of Fourier harmonics and integrating the material velocity of the tracked point in the frequency domain, this method gives an unbiased trajectory estimate in the presence of white measurement noise and eddy current effects. When applied to practical data, the method can incorporate compensation for the frequency response of the data acquisition method, offering a further improvement on the tracking accuracy. In simulation and phantom studies, the estimated trajectories were in excellent agreement with the true trajectories. Encouraging results have also been obtained on data from human beings.

Abstract: A device, and an associated method, for determining separation distances separating motor vehicles travelling along a roadway. A separation distance separating the motor vehicles is calculated responsive to targeting the vehicles with a laser range finder and determining the speeds of the vehicles. From this information, the separation distances separating the motor vehicles can be calculated. If the separation distance separating the motor vehicles is less than a minimum distance, then the calculated separation distance can be utilized by traffic enforcement officials to take appropriate enforcement actions.

Abstract: A digital particle image velovimetry (DPIV) method for contactless measurement of three dimensional flow velocities comprising the steps of seeding a flow with tracer particles; repeatedly illuminating a plane-like interrogation volume of the seeded flow; projecting the repeatedly illuminated interrogation volume onto at least a photo sensor in a projection direction for recording pictures of the illuminated interrogation volume; and determining the three dimensional flow velocities from the pictures of the repeatedly illuminated interrogation volume recorded by the photo sensor. The plane-like interrogation volume of the invention comprises at least two partial volumes positioned parallelly parallel to each other with regard to the projection direction. The step of repeatedly illuminating the interrogation volume comprises the step of illuminating the partial volumes in such a way that the pictures of different partial volumes are distinguishable from each other.

Abstract: A vehicular optical radar apparatus can identify various types of obstacles as well as a preceding vehicle, thereby ensuring a reliable identification of the preceding vehicle running in the same lane as with a subject vehicle on which the apparatus is installed. A scanner scans light emitted from a light emitting device and radiates it. A light receiving device receives the light which is radiated by the scanner and is then reflected by an object. A received-light intensity detection device detects an intensity of the reflected light received by the light receiving device. An obstacle identifying device identifies the object according to the distribution pattern of the received-light intensity detected by the intensity detection device, such a pattern being obtained with respect to the direction of scanning performed by the scanner.

Abstract: The invention is to an apparatus and method for determining the position and speed of a pitched ball. A collection box includes arrays of pulsed infrared emitter sensor pairs. As a ball passes between the emitter/sensor pairs, the signal between at least two emitter/sensor pairs are interrupted. The position of the interrupted emitter/sensor pairs and the time the signal between an emitter/sensor pair indicates the position and speed of the pitched ball.

Abstract: A laser Doppler velocimeter in which laser light whose frequency changes continuously at least for a fixed time duration is branched into at least two beams, and the at least two branched beams are respectively transmitted by at least one pair of optical fibers having an optical path difference therebetween, and are focused onto a region to be measured by at least one focusing device. The scattered light of the laser beams focused in the region to be measured are received by a light-receiving device via at least one incident device. At least one Doppler shift frequency in the region to be measured is calculated on the basis of the frequency of a signal of the scattered light received by the light-receiving device, the optical path difference, and a rate of change of the frequency of the laser light. The flow velocity and the direction of the flow velocity are calculated from the calculated Doppler shift frequency.

Abstract: A passive optical speed and distance measuring system includes a pair of camera lenses positioned along a common baseline a predetermined distance apart and controlled by an operator to capture images of a target at different times. The camera lenses are focused on light sensitive pixel arrays which capture target images at offset positions in the line scans of the pixel arrays. A video signal processor with a computer determines the location of the offset positions and calculates the range to the target by solving the trigonometry of the triangle formed by the two camera lenses and the target. Once the range to the target is known at two different times the speed of the target is calculated.

Abstract: A ballistic optical camera trigger having an integrated circuit capable of onverting light to a proportional frequency, wherein the integrated circuit has a fast response time and a wide dynamic range which allows it to sense positive or negative changes in light fast enough to trigger without delay for high speed imaging without computational delays or jitter causing interference. The frequency output of the integrated circuit is tracked by a phase lock loop/voltage controlled oscillator to allow it to follow slow changes in light, but not fast changes in light caused by, for example, a projectile such as a bullet. The frequency output from the integrated circuit is provided to one input of a logic gate which receives at another input thereof, a shaped pulse from the phase lock loop/voltage controlled oscillator circuit, wherein the output of the logic gate is applied to a one-shot for outputting a trigger signal.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: An apparatus for measuring the flying velocity of a spherical object, including ray projecting devices for emitting a plurality of parallel rays of light, ray receiving devices for detecting the incidences of said rays of light on them and the interceptions of said rays of light, an instrumentation device for measuring the time for which said rays of light are blocked off by a spherical object in flight, upon detecting signals given by said ray receiving devices, and an arithmetic operation device, such as a computer. The parallel rays of light emitted by using the ray projecting devices are arranged within a plane, and their respective positions are known quantities. The distance between every two rays of light is set such as to be less than the radius of the spherical object.

Abstract: An electronic keyboard musical instrument is provided having optical emitters and detectors both positioned beneath each of the instrument's keys, whereby optical energy is emitted upon the bottom reflective surface of the key and the reflected light is detected. The distance between the optoelectronic sensor and the bottom of the key is detected by the light detector which produces an analog output signal and, by measuring the time between a first and second threshold crossing, the key's velocity can be determined. The two thresholds are preferably chosen to measure a rising voltage as the key is depressed, and the threshold values are preferably chosen at 50% of key travel and 75% of key travel. By use of these thresholds, a relatively clean and useful waveform is available at both threshold crossings, particularly since the mechanical movement of the key has nearly reached its terminal velocity.

Abstract: An aerodynamic particle size measuring device includes a laser energy source and beam splitting, shaping and polarizing optics for forming two parallel, peripherally overlapping beams. The beams are caused to intersect a gas stream perpendicular to the direction of gas flow, thus to form a measuring volume at the intersection of the beams and flow. Single particles are carried through the measuring volume with the gas flow, each particle scattering and extinguishing light according to the beam profile, as predetermined by the degree of beam overlap and the Gaussian intensity distribution of each beam. A photodetector, responsive either to scattered light or light extinction, generates a time-dependent voltage profile that tends to replicate the intensity profile. The resulting electrical signal is processed to determine an amplitude, set a threshold for minimally acceptable amplitudes, and to derive two negative-going zero crossings for an unambiguous time/velocity determination.

Abstract: A device for measuring the speed of an object. The device includes a spatial filter scheme to provide quick-response photodetectors and an efficient use of light. The device projects light onto the object by a light source 1, and the light reflected by the object is received by a lens. This light passes through aperture stop 4 and strikes prism array 7, where it is split alternately into two paths at a fixed pitch with respect to the optical axis. The two split beams are received respectively by two photodetectors. The speed of the object moving relative to the measuring device can be calculated based on the data collected by photodetectors.

Abstract: A Holographic Diffraction Image Velocimetry (HDIV) providing the three-dimensional (3-D), three-component (3-C) detection of velocity or displacement field. The HDIV technique and system are based on the independent reconstruction of time-sequence scenes captured on a single recording plate by dual-reference-beam, off-axis holography. The local areas of individual images, without any specific-particle focusing, are then scanned section by section with a solid state camera to obtain sufficient readout resolution. For velocity extraction, the image section that best correlates to the original image in a plane window is computationally searched from a transplaced volume window in the displaced field. Initially, in-plane motion is found statistically by applying two-dimensional cross-correlation (CC) to the middle section of the volume window, obtained with an intermediate depth of focus of the imaging system.

Abstract: A laser speed detector is described which includes a laser rangefinder which determines the time-of-flight of an infrared laser pulse to a target and a microprocessor-based microcontroller. The device is small enough to be easily hand-held, and includes a trigger and a sighting scope for a user to visually select a target and to trigger operation of the device upon the selected target. The laser rangefinder includes self-calibrating interpolation circuitry, a digital logic-operated gate for reflected laser pulses in which both the "opening" and the "closing" of the gate can be selectably set by the microcontroller, and dual collimation of the outgoing laser pulse such that a minor portion of the outgoing laser pulse is sent to means for producing a timing reference signal.

Abstract: A velocimeter includes a light source for emitting a light beam through a flow, the flow including particles for scattering light as the light beam passes through the flow, a focussing device for focussing the scattered light into a particle image, a detecting device for detecting the particle image, and a device for timing passage of the particles through a predetermined section of the light beam. The detecting device includes at least one array of photodiodes for receiving light scattered by the particles. The array has a predetermined shape and is positioned so as to control a measurement volume geometry from which light scattered by the particles is received by the photodiodes.

Abstract: The speed, acceleration and profile of a moving target object, such as a vehicle, are determined by processing signals provided by an array of detector elements in response to detecting a pair of laser beams reflected from the target object. The speed, acceleration and profile determinations are processed to classify the vehicle as belonging to one of a plurality of different predetermined speed, acceleration and profile categories, respectively.

Abstract: Disclosed are a timing device for controlling machine tools, handling equipment or other servomechanical elements and a method of manufacture. The timing device comprises a timing control element which includes a plurality of transparent windows and opaque windows arranged in a selected pattern and a reflective means disposed behind the transparent and opaque windows for reflecting light. A transmitter emits light toward the timing control element. The device further comprise means for operating the timing control element to controllably select one of the transparent and opaque windows to be in the path of the emitted light. The emitted light propagates through one of the transparent windows, and is reflected by the reflective means only when the selected window is transparent. A receiver, disposed adjacent to the transmitter, generates an electrical signal in response to the reflected light.

Abstract: A distance-velocity predicting system has an illuminator for projecting a light beam for searching for an obstacle, and a plurality of position sensors spaced at a distance corresponding to a base line length. A minimum value of a distance component from the base line to an obstacle lying in a direction perpendicular to the base line, which is obtained from the light beam and the position sensors, or a value in the neighborhood of the minimum value, is sampled to obtain time-series data, and a relative velocity component in a direction perpendicular to the base line with respect to the obstacle is obtained in real time by using the time-series data. The relative velocity component perpendicular to the base line is compared with a predetermined threshold value, and when the relative velocity component exceeds the threshold value, a starting signal for life protecting equipment is generated.

Abstract: A PIV system provides a bias velocity component to each flow field speckle pattern recorded on a video array by rastering each corresponding recorded electrical image pattern by a select number of raster lines in the time interval prior to recording a succeeding speckle pattern image, thereby providing a calibrated spatial offset between recorded images.