Abstract: A light detection, signaling and speed measurement system. The system includes a housing having a first photosensitive surface mounted therein for detection of an incident light source approaching the system from any direction. The system further includes at least one light signal device mounted for visibility, along with circuitry responsive to detection of the incident light source for illuminating the light signal device. A second photosensitive surface is also provided to receive largely ambient light and to be nonresponsive to the light of the incident light source, along with circuitry to allow the illumination of the light signal device only when the second photosensitive surface detects the absence of a predetermined level of ambient light. The system further includes circuitry for detecting and indicating the velocity of the incident light source moving with respect to the system.

Abstract: An optical correlator having an imaging system for the non-contact measuring of the velocity and/or direction of motion and/or the distance of an object, and comprising at least one grating structure having lines thereon mounted at least in the vicinity of the image plane of the imaging system and at least one photoelectric receiver arranged after the grating structure in the direction of the light, the receiver converting the modulated light fluxes resulting from the grating structure into electrical signals, the improvement comprising a supplemental structural device inserted between the imaging system and the grating structure of the correlator for transforming spatial frequencies contained in the image of an object.

Abstract: The invention is a simple but efficient position and velocity identifying system to low-flying objects especially cruising missiles. Through a system of prism-complexes, the beams lased by four lasers (preferably injection lasers) are split into systems of orthogonally intersecting beam-quadruplets in parallel lying on the horizontal plane, each of which impinges a light-sensor-quadruplet. The curved air equidensity surfaces around the wings or the shock waves generated by a low-flying object passing by deflect a beam-quadruplet, such that the sensors of a light-sensor-quadruplet switch sequentially. The transient between the switchings, converted into a count, together with the sensor-quadruplet-address generated in an associated electronic circuit, are transmitted via a common multiple to a console where the count is converted into velocity there.

Abstract: A photographic camera with an electrical circuit for generating an electric signal proportional to the relative motion between the object sighted and the camera. The camera has a control circuit which receives the generated signal and provides an output signal which is fed to a display and/or control device. An indicator is provided to the user of the camera for indicating whether the exposure time is set too long for the relative motion present between the object and the camera. Automatic control of the camera is also provided. Individual photosensor elements are arranged in two alternately connected groups within the electrical circuit. The individual photosensor elements may also be arranged in two substantially perpendicular directions to provide a relative motion signal corresponding to two dimensional movement between the object to the photographed and the camera.

Abstract: A device for determining the velocity, trajectory and attitude of a projele. Light beams from two perpendicular linear arrays of light emitters are incident upon corresponding linear photodetector arrays. Each light beam in the linear arrays includes an individualized characteristic to permit unique identification of each beam. Trajectory and velocity parameters are determined by identifying which detectors have an interrupted light beam and from the time interval between actuation of the arrays.

Abstract: An apparatus for and a method of utilizing a magneto-optic stripe domain light deflector for both the transmitted and received light beam.

Abstract: A passive electro-optical collision avoidance system disposed within a moving vehicle for generating a collision avoidance signal. The system comprises a lens, image sensor and image processor wherein the image processor generates a collision avoidance signal in response to the size of the image and its rate of growth.

Abstract: An apparatus for detecting the passage of a moving object such as a truncated stern projectile includes a laser light screen, a photo sensor, and a signal processor. The intensity signal produced by the photo sensor is processed to generate an output pulse at the instant when the first time derivative of the intensity is greatest. For truncated stern projectiles this occurs when the projectile exits the light screen.

Abstract: In electrophoretic apparatus measuring the velocity of particles in a fluid, a reference beam and a scattered beam scattered by the particles in the fluid at various scattering angles must be heterodyned in order that the Doppler frequency shift resulting from the scattering by the moving particles can be determined. The previous need for adjusting the optical path of the reference beam so that is always impinges with the scattered beam, independent of the scattering angle, upon the mixer or heterodyner is avoided by an automatic control of the direction of the reference and scattered beams relative to the mixer so that they both always impinge upon a predetermined location in the mixer independent of the scattering angle. The construction of the measuring cell and ways of mounting same in a housing to allow easy refilling and replacement are also disclosed.

Abstract: A pick-up system includes means for recognizing the displacement of objects to be photographed relative to the optical reproduction plane. The shutter of the pick-up system is actuated according to the relative motion of said objects. In a pick-up system comprising a variable diaphragm and a replaceable film of a special sensitivity, e.g. in an automatic camera, the shutter speed, being a function of the relative motion of the objects, determines the aperture of the diaphragm with respect to the sensitivity of the film.

Abstract: The invention relates to a method for determining the magnitude and direction of the flow speed in a flowing medium comprising the following steps:(a) Irradiating the flowing medium in a first direction with a laser beam of a defined cross-section having a maximum principal dimension;(b) Observing a defined position (measured volume) in the longitudinal extent of the laser beam in a second direction at a defined angle to the first direction;(c) Measuring the pulse duration of diffuse light pulses given off in the second direction by particles of a defined size contained in the flowing medium and passing through the measured volume; and(d) Turning the laser beam cross-section about the rotary axis defined by the first direction until diffuse light pulses of maximum pulse duration can be observed.By means of this method one obtains in a single measuring operation an indication of the magnitude and direction of flow in the plane formed by the laser beam and the flow direction.

Abstract: The invention relates to an optical correlator comprising an optical system for imaging an object space, a spatial frequency filter disposed in or close by the image plane, and at least one photoelectric detector assigned to said spatial frequency filter. According to the invention the spatial frequency filter is a raster, the structures of which extend in the direction of the perspective vanishing lines of the image of the object space and/or perpendicularly to at least one of said vanishing lines. The size of the structure elements and/or the distance between the elements constituting the raster structure are chosen according to the distortion of the perspective image.

Abstract: A flow velocity meter is described suitable for measuring the mean flow velocity of a medium flowing along a duct using optical means which generates first and second beams of light each in the form of a relatively shallow wide band which traverse the duct across first and second spaced apart transverse planes which are arranged substantially at right angles to the mean flow direction. Light beams emerging from the duct are received on respective photoelectric detectors the output signals of which are essentially identical but relatively displaced because of the time required for the medium to flow between the two planes. By processing the signals in a correlation circuit this time is established and is used to produce an output proportional to the mean flow velocity of the medium between the two planes. The correlation circuit used is based on digital techniques.

Abstract: The accuracy of an optical measuring system is improved by directing a parallel light beam across the surface of a moving object in a direction perpendicular to the direction of movement so that movement of the object in the direction of the light beam will not affect the measurement accuracy. For measurement purposes, the silhouette of the object can be roughened by coating with an easily removable foreign substance such as wheat flour.

Abstract: System for measuring the relative position and/or velocity of two objects with respect to each other and/or with respect to a common reference system, such as the ground, according to the magnitude and direction thereof, using electro-optical measuring means, the improvement comprising:(1) producing images of the object to be measured in at least two different spatial positions;(2) producing A.C. electrical signals of different frequency proportional to the relative movements of these images to at least one optical correlation system; and(3) evaluating these signals, with the use of the trigonometrical relationships of the perspective imaging, in a computer to determine the measured values.

Abstract: A method for separately evaluating the contents of an image in two coordinate directions of motion by splitting and then reflecting the received image so that the images may be separately analyzed.An apparatus for performing the method which comprises a beam splitter, a reflector and a correlating grid.A method of measuring distance by using the apparatus of the invention is also disclosed.

Abstract: The beam produced by a pulsed laser is directed onto a mobile and, once reflected, is heterodyned in a mixer with the light wave produced by a local laser operating in continuous mode.A part of the beam produced by the local laser is directed onto the target. The output of the mixer is applied to an opto-electronic circuit which derives a composite electric signal which is separated by appropriate filters into a first component representative of the distance from the mobile and a second component representative of the radial velocity of the mobile.

Abstract: A laser generator (1,2,3) is arranged to generate successive pairs of pulses. Two light receivers (10,11) in the vicinity of the laser generator receive echos of the pulses as reflected from a target and a processing circuit (15) calculates the component of wind speed blowing across the laser axis between the laser generator and the target. The device can be combined with laser ranging means and used for artillery control.

Abstract: In order to provide a system for measuring relative velocity of a surface with the accuracy of a laser velocimeter but avoiding the problems associated with operating down to zero speed and with signal dropout during a run, a tachometer is coupled to measure the relative velocity and the output of the tachometer corrected using the output of the laser velocimeter thereby giving laser velocimeter accuracy over the major portion of the velocity range but still permitting operation down to zero speed and operation when signal dropout occurs.

Abstract: A method and apparatus for inducing a Doppler frequency shift in a reference beam laser velocimeter light beam to simulate target velocity wherein the light beam is passed through a rotating refractive transparent block positioned between two reference points along the beam resulting in a continuous change in the light beam optical path length between the reference points according to a known function. The velocity indicated by the laser velocimeter is compared to the known simulated velocity function for velocimeter testing and calibration.

Abstract: A method and apparatus for the automatic evaluation of stereoscopic images by the determination of the maximum degree of correlation of identical images of an object reproduced by two objectives, for example for a range finder, wherein the two images are superimposed on one and/or two position frequency filters (82, 21, 31, 32) identical in their structures; the respective superimposed signal produced is fed respectively to one photoelectric receiver (13,14,43,44); and the output signals of the photoelectric receivers are used for indicating and/or control purposes. In one embodiment the position frequency filter (82) is moved and the output signals are correlated with each other. In another embodiment the output signals are subtracted from each other.

Abstract: A sensor for measuring the velocity components of particles in an atmospheric volume which comprises means for generating first and second coherent radiation beams, means for directing said first and second radiation beams towards said particles, said beams being spaced apart and positioned to intersect each other in the region of said particles, said particles having a longitudinal velocity component along the bisector of said beams and a transverse velocity component perpendicular thereto, means for receiving Doppler-shifted radiation back-scattered from said first and second beams, a reference beam of radiation temporally coherent to said first and second coherent beams, means for mixing said temporally coherent, reference radiation with said received Doppler-shifted radiation for detecting a beat frequency spectrum, and means connected to receive said beat frequency spectrum for determining from the frequency values of said beat frequency spectrum, the average longitudinal and transverse velocity componen

Abstract: The relative transverse velocity between a local station and a zone of reference or observation is measured by providing first and second directional radiation receiving devices at the local station, such devices being aimed along parallel paths extending to the zone of reference. Such paths are spaced apart by a predetermined transverse distance. The first and second radiation receiving means include respective first and second converting means for converting the received radiation into first and second electrical signals. Any transversely moving radiation feature produces corresponding signal features in such first and second signals, such signal features being staggered with respect to time. The lapse of time between such staggered signal features is determined by time lapse measuring means. The velocity of such transverse movement is inversely proportional to such time lapse.

Abstract: Blood flow in retinal blood vessels is measured by directing laser radiation along an optical path into the eye and onto a blood vessel. Laser radiation reflected off moving blood corpuscles is directed back along the optical path and into a detector. This reflected laser radiation is mixed with a proportion of the original laser signal to determine the doppler shift produced by the moving blood corpuscles and hence blood velocity.

Abstract: A multiple frequency laser technique for enhancing the detection of discrete targets amid a clutter background while also increasing the range performance or power limits of the laser type radar. Each of a plurality of laser oscillators cooperates by heterodyned phase-lock means to provide a mutually exclusive one of a plurality of mutually coherent frequencies, whereby the transmitted continuous wave energy comprises a coherent pulse train.

Abstract: Apparatus for measuring velocity is disclosed. The apparatus in its prefed embodiment comprises a first lens and a first array of photodiodes and a second lens and a second array of photodiodes. The photodiode arrays are functionally equivalent to low resolution vidcon camera tubes and momentarily store the image. As an object passes beneath the first lens, its image is stored on the photodiode array. The object then passes beneath the second array and the image is stored on the second array. After the image is stored on the second array a correlation is made between the two images by making an element by element comparison of the serial outputs of the two arrays. Instead of relying on the storage properties of the arrays to make the correlation, the arrays can be read into a small memory for comparison. Each array is exposed for only a short period of time. The invention includes apparatus for controlling the time interval between the exposures.

Abstract: An optical apparatus, particularly suited for use in a ballistic measurement device, including a laser generating a laser beam, an optical means for expanding the laser beam in a plane, and an optical element, positioned between the laser and the optical means, for dividing the laser beam into a plurality of beams of substantially identical intensity so that a substantially uniform brightness results over the entire angle of divergence of the laser beam.

Abstract: A system for detecting a reflected light beam includes a source of coherent light such as a laser beam, an optical fiber spaced away from the source for receiving an incident beam of coherent light from the source at one end of the fiber, means for reflecting a portion of the incident beam back through at least a portion of the fiber to radiate a reflected beam which includes narrow angle signals having a beam width corresponding to that of the incident beam and wide angle signals having a beam width substantially wider than that of the incident beam, receiving means between the source and the optical fiber for receiving the reflected beam and having an optical aperture therein for transmitting the incident beam and the narrow angle signals in the reflected beam, and a projector lens between the receiving means and the optical fiber for directing the incident beam into the optical fiber and for directing the narrow angle signals in the reflected beam into the optical aperture of the receiving means.

Abstract: A light source illuminates particles migrating in an electrophoresis chamber under the influence of a reversing polarity electric field applied between a pair of spaced electrodes which are in the form of thin conductive layers deposited on opposed end portions of the chamber. The light reflected from the particles migrating along the stationary layer of the chamber is imaged onto a circumferentially arranged grating on a transparent rotating disk and modulated thereby.

Abstract: A beam of laser light is impinged on a vessel or vessels in which blood is flowing, such as vessels in the retina of the eye. The reflected light is detected with a photodetector to product a signal representative of the Doppler shift frequencies of the light scattered from the moving blood cells. If the light is impinged on a capillary bed the photodetector produces a homodyne type signal, from light reflected from blood in the various capillaries; if the light is impinged on a single vessel the photodetector produces a heterodyne type signal from the light reflected from the vessel wall and the light reflected from the blood cells flowing in the vessel. The signal from the photodetector is amplified and used to drive an audio output to produce a sound representative of the velocity of the blood.

Abstract: A coherent optical modulated sensor for use with missiles and the like wherein a series of pulses of optical energy which are intensity modulated by a radio frequency sub-carrier are transmitted to a preselected target having relative motion thereto and wherein returned pulses from the target are received. Phase coherence is effectively maintained by utilizing a single continuously operating local oscillator for down-converting the received detected pulses to a Doppler frequency signal. Target velocity information may be extracted from the Doppler frequency shift induced on the coherent radio frequency sub-carrier of the return pulses.A first channel, or radio frequency sub-carrier channel is provided for receiving the Doppler signal and generating a threshold signal in response to the magnitude of the Doppler signal being equal to or greater than a predetermined magnitude. A second channel (baseband) detects the average direct current power of the received pulse.

Abstract: A microscope system for observing moving particles makes use of a television camera for producing a continuing series of images of such particles. A source of light pulses illuminate the particles with each pulse for a period short enough to stop their movement for the camera. The light source and camera are synchronized so that the light pulses occur only between times that the camera produces image-information signals. For obtaining particle size measurements, a single light pulse during a time that the camera is not producing image-information signals is sufficient. For obtaining paticle velocity measurements, two light pulses are required so that a "double exposure" occurs at the camera during a time that the camera is not producing image-information signals.

Abstract: Apparatus for measuring an aircraft's horizontal speed and height above ground without the need for airborne cooperative devices. Two ground level TV cameras separated by a measured distance and pointed at zenith are placed in line with the projection of the expected path of the aircraft. Speed is determined by measuring the time that it takes the aircraft to travel between the fields of view of the two TV cameras using zenith crossings as the reference points. Height is determined by correlating the speed with the time required to cross the field of view of either of the two cameras.

Abstract: Laser altimeter/profilometer apparatus utilizing a CW CO.sub.2 laser transmitter mounted on an aircraft so as to transmit a narrow laser beam towards the terrain below the aircraft. The scattered laser signals are received in a receiver mounted on the aircraft, some distance along the fuselage from the transmitter, and the doppler shift in frequency of the received signal is determined. That doppler shifted frequency is utilized to calculate the altitude of the aircraft above the ground over which it is flying.

Abstract: An LDV optical system for projecting a two-color, two-axis interference fringe system and collecting backscatter radiation for two component velocity measurement. A rotor within an optical head of the system having a pair of beam splitters and a two-color filter provides two pairs of diametrically opposed split beams in orthogonal planes and with the split beams equidistant from the axis of the rotor and is angularly adjustable for setting the angular orientation of the fringe system. In a modified embodiment, a rotor with a single beam splitter providing a single pair of diametrically opposed split beams is connected to a motor to be rotated between 90.degree. limit positions for two component velocity measurement using two colors for the measurement of each component.

Abstract: A detector of remote movement in which light from a laser is directed at a target and, on reflection from the target, is mixed with reference light from the laser to produce a Doppler signal denoting the movement of the target. The beam of light from the laser is directed through an optical system which brings the light to a focus and thereafter projects the light from the focus at the target. The optical system includes a lens which is mounted in a ferromagnetic carrier which can be vibrated in two orthogonal directions each normal to the axis of the light beam and the axis of the lens. Coils disposed to produce these orthogonal movements are energized in quadrature so as to produce conical scanning of the beam of light on the target.

Abstract: An optical detector of remote vibration, comprising a system for obtaining a Doppler signal by mixing reference light with laser light reflected from a vibrating object. The Doppler signal is rectified and the successively highest value of it are stored. The laser light is scanned over the object and the values of scanning waveforms at the time of storage of a maximum return signal are stored, the stored values being read out to control the direction of the laser light so as to locate the region giving maximum return.

Abstract: To measure the distance between a master station at a first location and a slave station at a second location, an interrogation pulse -- e.g. of light -- sent out by a transmitter at the master station is intercepted by a receiver at the slave station and, after a delay period T, triggers a transmitter at the latter station to send back a reply pulse to a receiver at the master station. The reply pulse starts another delay period T at the slave station, followed by the emission of a follow-up pulse. At the master station, the duration of the delay period T -- as measured from the arrival of the reply pulse to that of the follow-up pulse -- is deducted from the time measured between the emission of the interrogation pulse and the reception of the reply pulse to give an indication of the distance between the stations. Since this indication is independent of T, the delay period may be made variable to serve as a gauge for some other quantity such as the speed of a vehicle carrying the slave station.

Abstract: A method and apparatus for the rapid measurement of the distance of an object from a reference point and the speed component of an object traveling vertical to a reference plane is disclosed. A laser beam from a transmitter is periodically sent by a beam deflector through the space in which the object is situated. The laser beam is diffusely reflected from the object and is registered as a measurement pulse on a detector placed near the transmitter. The distance of the object is determined from the time difference between one starting point of a deflected beam segment selected for the measurement and the detector signal. A reference pulse is created in an additional reference detector at a reference time by positioning a swing mirror so that a portion of the laser beam is reflected on a transparent body situated on the reference plane, the reflection then impinging upon the reference detector. The time difference is measured from the reference time to the middle of the measurement pulse.

Abstract: Method and apparatus for measuring distance using an optical correlator system containing at least one imaging optic, at least one optically active array, and at least a system of photoelectric detectors associated with the array preferably in the form of an optical grating structure wherein for the purpose of unambiguous distance or range determination by means of optical-geometric steps in the image region and/or in the Fourier space, different beam guidance systems are constructed so that for axial relative motion between object image and array output signals are generated at each photoelectric detector system associated with each beam guidance system, these output signals differing among themselves in frequency and hence (also) in phase. A comparison is made of the output signals and from the comparison the geometric image position of the principal maximum is determined with respect to the geometric positions of the secondary maxima.

Abstract: An apparatus for measuring the flow parameter of blood flowing in an organ includes a laser and associated optics which effect the illumination of tissues. The laser light, scattered by the tissues, emerges with a spectrum broadened by Doppler effect due to motion of red blood cells in the micro-circulation vessels. The light from the tissues is fed to a photomultiplier tube or photodiode via a pinhole mask and interference filter. The photomultiplier tube or photodiode, as a result of beating of various components of the light it receives, produces as its output signals a homodyne or heterodyne spectrum or both. These output signals are fed, via a low pass filter, to a differentiator, which differentiates the output signals from the multiplier tube or photodiode, which are passed by the filter, with respect to time. The output of the differentiator is fed to a root-mean-square (RMS) detector. The low pass filter passes, for example, signals having a frequency up to about 20 KHz.

Abstract: A probe comprises a sealed first tube part terminating at one end in a wiw with an open support extending away from the window and constituting an extension of the tube and carrying a reflection device such that incident light beams passing through the window and onto the reflector are reflected to converge on a measurement point within the open support intermediate of the reflector and window. A light detection device within the sealed tube protects the variations of light on the measurement point.

Abstract: A method and apparatus is disclosed for determining the velocity of a document over a fixed distance of travel. Sensing means are provided for generating signals which are used in determining the value of the time the document requires to move over the fixed distance. Using terms of a Taylor series expansion of the velocity equation, a value of the velocity is determined utilizing digital elements requiring only multiplication and addition operations. The elements include a digital multiplier and accumulator together with a plurality of storage devices which utilize the value of the time together with a plurality of predetermined constants to determine and output the value of the velocity to a display which displays the velocity in numerical form.

Abstract: Coherent electromagnetic radiation is directed upon particles suspended in a fluid medium to produce scattered radiation. The particles are subjected to an electric field alternating between a first and second intensity. The coherent radiation and the scattered radiation are directed upon a detector to produce a heterodyne signal the spectrum of which is analyzed. The spectral composition of the heterodyne signal obtained with the first intensity of applied electric field is compared with the spectral composition obtained with the second intensity of applied electric field to provide a measurement of the electrophoretic mobility of the suspended particles.

Abstract: A laser range finder utilizing a mode locked laser for measuring target range with a high degree of accuracy and simplicity by measuring the time of flight of a transmitted pulse utilizing the pulses in the laser cavity for clocking a range counter. The laser consists of mirrors with at least one being semi-reflective, an amplifying medium and a suitable method of mode locking. A switch is provided outside of the cavity for transmitting a gated train of ultra short pulses or a single pulse to a target. The return signal is processed, detected and sent to an electronic circuit which uses the detected signal to stop a counter at the proper range count. The pulses inside the cavity are detected after they pass through one of the mirrors to provide the range counting pulses as well as to energize the switch outside of the cavity at the proper switching time.

Abstract: A control circuit for maintaining the sensitivity of an avalanche diode at an optimum is shown. Such diode, when used as a photosensitive detector in a receiver in an optical radar, is biased by the disclosed control circuit so that the frequency at which internally generated noise impulses are generated is maintained at a predetermined rate so that echo signals may be distinguished from such impulses.

Abstract: A system for determining photoelectrically the position of at least one focus plane of an image within an optical apparatus, wherein the object is reproduced at least at one spatial frequency filter of an optical image correlator and there is measurement and/or display of the light fluxes leaving the local frequency filter.In this system light fluxes traversing differing pupil sections of the reproducing optics are modulated in common by a spatial frequency filter and are split up geometrically or physically, or by means of additional modulation in correspondence with the pupil sections. They are consecutively or simultaneously projected on a common photoelectric receiver or on separate photoelectric receivers, the output signals of which are processed further for purposes of controlling display and/or follow-up devices.

Abstract: The invention is an optical scanner that sequentially focuses optical energy (light) at selected points in space. The essential component of the invention is a scanning wheel including several glass windows with each window having a different thickness. Due to this difference in thickness, the displacement of the emerging light from the incident light is different for each window. The scanner transmits optical energy to a point in space while at the same time receiving any optical energy generated at that point and then moves on to the next selected point and repeats this transmit and receive operation. It fills the need for a system that permits a laser velocimeter to rapidly scan across a constantly changing flow field in an aerodynamic test facility.

Abstract: A remote site optical transponder device which automatically amplifies an incident laser pulse and returns it to its source is described. The device is especially useful in high precision ranging e.g. determining the motion of planets accurately and in tracking space craft. The device is powered by a long life power source and has a steerable laser light collector / transmitter system. Other essential components are a laser amplifier medium whose excitation means is triggered by part of the energy contained in an incident pulse from a laser tracking system and also a reflector.

Abstract: A laser beam is expanded by means of a beam expander device, the expanded beam striking the surface of a mirror which has an aperture formed therein. A portion of the beam passes through the aperture and is focused so that it strikes an optical detector. The major portion of the beam is reflected from the mirror surface to a scanner mirror which provides a transmitter beam to scan targets to be detected. A beam received back from the targets also strikes the scanner mirror and is reflected by this scanner mirror to a corner reflector, the beam being displaced a predetermined amount by the corner reflector and reflected therefrom in a direction precisely opposite to that of the beam incident on the corner reflector. This beam, after being reflected by the corner reflector, strikes a reflective surface of th apertured mirror directly opposite to that on which the laser beam is incident.