Abstract: A planar velocity measurement system (100) is operative to measure all three velocity components of a flowing fluid (106) across an illuminated plane (108) using only a single line of sight. The fluid flow is seeded with small particles which accurately follow the flow field fluctuations. The seeded flow field is illuminated with pulsed laser light source (102) and the positions of the particles in the flow are recorded on CCD cameras (122,124). The in-plane velocities are measured by determining the in-plane particle displacements. The out-of-plane velocity component is determined by measuring the Doppler shift of the light scattered by the particles. Both gas and liquid velocities can be measured, as well as two-phase flows.

Abstract: A LIDAR system for measuring flow velocity in three axes comprises: a LIDAR arrangement of optical elements for generating a coherent beam of light and directing the coherent beam of light by at least one rotationally operated optical element from the system with a predetermined pattern, the at least one rotationally operated optical element also for receiving reflections from particles along the predetermined pattern and directing the beam reflections to a light detector which converts the beam reflections into representative electrical signals; and a processor for detecting bursts from the electrical signals which are representative of light beam reflections from at least one particle substantially at a corresponding position along the predetermined pattern, and for computing a Doppler frequency for each of a selected plurality of detected bursts from the signal content thereof.

Abstract: A three-dimensional imaging range finder is disclosed using a transmitted pulse reflected from a target. The range finder includes a pixel sensor for receiving light from the target and the reflected pulse. A global counter is provided for determining a time-of-flight value of the transmitted pulse by providing accurate count data to pixel memories. A processing circuit, which is coupled to the pixel sensor and the global counter, extracts the reflected pulse received by the pixel sensor, and stores the time-of-flight value upon extracting the reflected pulse. The pixel sensor provides a luminance signal and the processing circuit includes a high pass filter to extract the reflected pulse from the luminance signal.

Abstract: A method measures the three dimensional position of particles in a fluid medium contained in a sample by recording a digital hologram of the particles on an image sensor and by reconstructing the image of the particles from the hologram. The recording includes providing a source beam with a coherent source, and generating at least two beams from the source beam, namely a reference beam and at least one object beam, wherein the reference beam and the object beam are mutually coherent. The sample is illuminated by condensing the object beam onto the sample in order to obtain a scattered object beam for each particle. The scattered object beam is scattered into a spherical converging object beam toward the image sensor for each particle.

Abstract: Frequency domain velocity measurements and time domain velocity measurements are made using light from cells or other objects. An optical grating is used to modulate the light from an object so that it has a frequency proportional to the velocity of the object. Depending upon the embodiment, the pitch of the optical grating is uniform or varying. The modulated light is detected and various signal processing techniques, such as a Fast Fourier Transform function, are used to indicate the velocity of the object. Preferably, the velocity measured is applied in determining a timing signal employed for synchronization of an image of the object and an detector signal in an optical analysis system that uses a time delay integration detector to determine characteristics of the object in response to light from the object.

Abstract: An apparatus and method for measuring a scrub radius of a wheel including determining at least one of a steering axis, a centerline and a ground plane of the wheel using computer-aided alignment, and determining the other of the steering axis, the centerline and the ground plane of the wheel not determined using computer-aided alignment. The method also includes determining an intersection between the steering axis and the ground plane of the wheel, determining an intersection between the centerline and the ground plane of the wheel, and determining a distance between the intersections, the distance being equal to the scrub radius of the wheel.

Abstract: An alignment device mounts to a missile system such that the view of a missile seeker is limited to limited fields of view at predetermined positions relative to a known reference such as the missile centerline. Once the alignment device is mounted to the missile system, an energy source emitting energy viewable by the seeker is located within a field of view. Once the seeker has locked-on to the energy source in a limited field of view, the pointing angle of the seeker can be observed by a measurement device communicating with the missile controller. Any pointing angle observed by the measurement device which differs from the known position defined by the alignment device, represents a displacement error of the seeker. Appropriate compensation is then applied to the missile controller such that alignment errors are accounted for.

Abstract: A method and device for measuring the speed of at least one object by Doppler effect, whereby the light diffused by an object illuminated by a laser sheet is transmitted to a CCD video camera by spectral filtering means which are substantially tuned to the laser illumination frequency, means being provided to generate reference monochromatic luminous fluxes having frequencies which are different from the laser illumination frequency by fixed known amounts, and the reference luminous fluxes being transmitted to the CCD video camera.

Abstract: A rangefinder device and a camera are provided, which, in measuring a distance by the active method, are capable of properly measuring the distance even if the object to be measured is located at a short distance, while in measuring a distance by the passive method, are capable of measuring the distance without causing the conflict between far and near objects. A projecting section projects spot-shaped light on a range-finding object. A light receiving section comprises a plurality of photoelectric converting elements. A first calculating section calculates distance measurement information based on an output from the light receiving section receiving reflected light from the range-finding object, by driving the projecting section to project the light, and a second calculating section calculates distance measurement information based on an output from the light receiving section receiving extraneous light reflected from the range-finding object, without driving the projecting section.

Abstract: A three-dimensional imaging system is fabricated on a single IC. The system includes a two-dimensional array of pixel light sensing detectors and dedicated electronics and associated processing circuitry, all preferably fabricated on a single IC using CMOS fabrication techniques. The system includes a detector array comprising a plurality of pixel photodiodes and photodiode circuits, wherein each pixel photodiode acquires delay time data and pulse brightness data simultaneously. The system emits an energy pulse at time t0 and a fraction of the energy is returned to the array by a target object. Photodiodes in the array output a brightness signal B(t) that is integrated. An elapsed time ET from t0 to when said B(t) attains a predetermined threshold value is determined, where the slope of B(t) is B/PW, where B is B(t) after integrating over a time equal to the emitted pulse width PW.

Abstract: An improved, low-cost optical transmitter and method useful in a three-dimensional measurement system wherein a plurality of operational parameters of said transmitter are calibrated during manufacture/assembly process to generate unique calibration data for each optical transmitter including data defining angles of each transmitter's first and second radiant fan beams and the angle between the beams when the transmitter is leveled for operation in the system and wherein a detector/receiver in the system distinguishes between radiant beams from a plurality of individual transmitters operable within a given measurement field as a function of the selectively alterable rotational velocity calibration data for each of said transmitters and wherein said angular calibration data for each transmitter is operationally available to each detector/receiver operable in the system.

Abstract: A preferably CMOS-implementable method measures distance and/or brightness by illuminating a target with emitted optical energy having a modulated periodic waveform whose high frequency component may be idealized as S1=cos(&ohgr;·t). A fraction of the emitted optical energy is reflected by a target and detected with at least one in a plurality of semiconductor photodetectors. Photodetector quantum efficiency is modulated to process detected signals to yield data proportional to the distance z separating the target and photodetector. Detection includes measuring phase change between the emitted optical energy and the reflected fraction thereof. Quantum efficiency can be modulated with fixed or variable phase methods and may be enhanced using enhanced photocharge collection, differential modulation, and spatial and temporal multiplexing. System power requirements may be reduced with inductors that resonate with photodetector capacitance at the operating frequency.

Abstract: A method and device (1) are proposed for accurately measuring in a reliable manner the distance of an object (99). The method comprises the steps of emitting a signal (such as a laser light beam), directing the signal to an object (99), detecting the signal diffused by the object (99), and comparing the detected signal with the emitted signal to obtain a comparison signal representing the distances travelled by the emitted signal and the signal diffused by the object (99) (for example, by sending modulated laser light and then measuring the phase difference between the emitted and received signals). The method of the invention is characterized by a step of setting the measuring device in order to define a reference operational configuration within the device.

Abstract: One version of the invention relates to a laser detection system that includes a ball lens and a plurality of fiber optic bundles placed adjacent the ball lens so that incoming light rays are focused onto the bundles by the ball lens. In one particular version of the invention, a ball lens is one that can provide an almost infinite number of “principal” axes for off-axis light. Each fiber optic bundle is aimed in a different direction from each other bundle so that each bundle will have a different FOV even though the same ball lens is used to focus the incoming light rays.

Abstract: Frequency domain velocity measurements and time domain velocity measurements are made using light from cells or other objects. An optical grating is used to modulate the light from an object so that it has a frequency proportional to the velocity of the object. Depending upon the embodiment, the pitch of the optical grating is uniform or varying. The modulated light is detected, producing an analog signal that is then digitally sampled. Time domain signal processing techniques are used to determine the velocity of the object from the digital samples. Preferably, the velocity measured is applied in determining a timing signal employed for synchronization of an image of the object and an detector signal in an optical analysis system that uses a time delay integration (TDI) detector to determine characteristics of the object in response to light from the object.

Abstract: A tacheometer telescope, i.e.

Abstract: A laser radar-proximity fuse with a laser-range measuring device and mask or camouflage discrimination, wherein for the initiation of the fuse, is no longer triggered at the beginning rather but at the end of an echo pulse configuration, even though its comparatively flat descending or falling pulse flank is or is not adapted for the determination of a clear, reproducible or controllable triggering point-in-time. By applying a Constant-Fraction-Trigger-Principle, which has heretofore been applied primarily to the rising or ascending flank of a pulse, there can be also derived a good controllable range or distance-dependent triggering pulse for the thereby optimized initiation of the fuse from the flatter rear flank of the echo pulse configuration, whereby the attacking of the target will not take place prematurely, but will be better directed toward the target center.

Abstract: A casing is provided for a reflection measurement device emitting a scanning beam and receiving an echo beam caused by reflection of the scanning beam at an object, and detecting a distance to the object in response to the received echo beam. The casing has a window for conducting a beam, and a protective member being transparent to the beam and covering the window from an inside. A predetermined range through which the beam passes is provided in the window. An interval between a lower edge of the beam pass range and a lower edge of the window is greater than an interval between opposing edges of the beam pass range and the window which differ from the lower edges thereof.

Abstract: An optical amplifier having a reflector to reflect spontaneous emission light back into the amplifier, to improve excitation efficiency. More specifically, the optical amplifier includes an optical fiber and a reflector. The optical fiber is doped with a rare earth element. An excitation light is provided to the optical fiber so that a light signal is amplified as the light signal travels through the optical fiber. Spontaneous emission light is generated in the optical fiber and travels in a direction out of the optical fiber. The reflector reflects the spontaneous emission light back into the optical fiber.

Abstract: A method and apparatus for determining the range of an object. A first image of at least a portion of the object viewed from a first position is generated. A second image of the portion viewed from a second position spaced apart from the first position is generated by calculation from the first image and the distance between the first and second position. It is assumed that all of the portion represented by the first image lies on a radius less than the distance to the object. A third image of the portion viewed from the second position is generated and the range determined by comparison of the first and third images.