Abstract: A high altitude lidar system propagates a beam of laser pulses through clearings in a cloud formation which reflects off the surface of the earth thereby providing first earth surface returns and reflections towards the base of a cloud that again reflects the pulses back towards the earth surface to be reflected again to provide cloud base returns. The time differential between the earth surface returns and the cloud base returns are used to determine the altitude of the base of the cloud.

Abstract: In a fee charging system for video information, scramble signals including video information and charging information can be recorded on a recording media such that the signals are read later therefrom. The recording of the scramble signals is free of charge. In an operation to reproduce original unscrambled video signals from the signals read from the media by a recording and reproducing apparatus, the charging information is detected to conduct a charging process. Consequently, although the scrambled signals may be freely copied onto another recording media, the charging process is executed for each copying operation. First charging information and second charging information other than the first charging information are arranged with the video information. The video information includes first video information as main video information and second video information.

Abstract: Laser distance-measuring instrument for large measuring ranges having a transmitting channel and a receiving channel arranged parallel to one another, the receiving lens being a modified single lens comprising a primary lens region with a primary optical reception axis which is aligned parallel to the optical transmission axis, as well as a secondary lens region with a secondary optical reception axis which is inclined to the primary optical reception axis at an angle &agr;, with the result that a primary focal point and a secondary focal point are produced.

Abstract: The present invention provides an optical device for the measurement of flow rates of fluid through a pipe. The device broadly comprises a narrow frequency light source, an optical delivery system, a collector for light scattered from particles in the fluid, and a photo detector. In a preferred embodiment, the optical delivery system and the collector are contained within the pipe.

Abstract: A consolidated laser alignment and test station. In exemplary embodiments, equipment sufficient to perform complete dynamic testing and alignment of a laser transceiver unit is provided in one compact arrangement. As a result, cavity-box efficiency testing, dynamic open-interferometer alignment, dynamic open-case alignment, closed-case laser boresighting, and complete laser functionality and diagnostic testing can be carried out efficiently at a single location. Real-time diagnostic feedback relating to beam quality, radiometry, and temporal behavior is provided so that high-precision laser alignments and repairs can be made quickly and cost effectively. Customized test fixtures provide easy access to every level of the transceiver unit under test, and two cameras provide far-field, near-field, wide-field and receiver-field beam viewing.

Abstract: The present invention provides a laser reference level setting device, by which it is possible to adjust irradiating positions of a laser beam in vertical and horizontal directions with a simple arrangement and without additional manpower and to measure a tilt angle. The device comprises a laser sighting device and a target, the target having a reflection surface for indicating a given position on the target, and the laser sighting device comprising a laser oscillating device having an emitting means rotatably supported and for emitting a laser beam and a light receiving means for receiving a reflection laser beam, a driving unit for rotating at least the laser beam emitting means of the laser oscillating device, and a control unit for controlling the driving unit to direct the laser beam to a given position on the target according to the light receiving condition of the reflected laser beam reflected from the reflection surface of the target.

Abstract: The invention provides a method and apparatus for guiding a weapon to a target using an optical seeker having dual semi-active laser (SAL) and laser radar (LADAR) modes of operation. The dual mode seeker incorporates a laser light source, an optical package including a quadrant detector for operating in SAL mode and a LADAR receiver for operating in LADAR mode. The seeker further includes a high speed scanning mirror for switching between modes to guide the weapon to the target. The method for guiding a weapon to a target includes receiving radiation from the target and tracking the radiation to guide the weapon; monitoring the detected radiation such that if the radiation falls below a predetermined level, a laser system on-board the weapon continues guiding the weapon by generating a laser beam; reflecting the laser beam off the target so that the reflected laser radiation is received from the target to track the radiation and guide the weapon to the target.

Abstract: Provided is an approach to efficiently correlate a previously captured digitally created image to one provided in real-time. The real-time digitally created image is represented by the digitally processed image of just the edges of objects within a scene. This is accomplished via digital edge extraction and subsequent digital data compression, based on comparing only the spatial differences (e.g., range values) among pixels. That is, digital data representative of signal intensity are not used. An application is the efficient correlation of real-time digitally processed 3-D images generated from laser scans, in particular, scans of laser “radars” or LADARS. The process simplifies and improves on conventional techniques by iterating three sequential steps. A “hard” edge or a corner of an object is detected via a “corner-detector” algorithm that assigns a raw edge-strength value to each pixel in the image digitally created from the LADAR return.

Abstract: An optical fiber amplifier for WDM-signals comprises an active optical fiber pumped with pumping light from a pump source. In order to give the amplifier a constant gain for the WDM-signals irrespectively of the number of active WDM-signals an additional light source is arranged to inject, when required, extra light into the active optical fiber, at least in a portion thereof, through a power combiner. The injected light has a wavelength different from that of the WDM-channels and preferably longer so that it will not cause an amplifying or pumping effect in the active optical fiber but so that it still can be amplified in the active fiber. The light source is controlled by a signal derived from an output power measurement device so that it will inject extra light when a WDM-channel becomes inactive. The power of the extra light is thus selected to saturate the optical fiber amplifier at a constant gain irrespectively of the number of signal channels, i.e. of the total power of the input light signals.

Abstract: In a rangefinder apparatus, a clamp signal is set to Ic1, the number of accumulating operations of an output ratio signal in an integrating circuit is set to N1, and a first distance measurement value D1 is detected. If the first distance measurement value D1 is larger than a reference distance L1, then the clamp signal is further set to Ic2, which is lower than CI1, the number of accumulating operations is set to N2, and a second distance measurement value D2 is detected. If the difference obtained by subtracting the first distance measurement value D1 from the second distance measurement value D2 is larger than a threshold value DD, then the clamp signal is set to Ic2, the number of accumulating operations is set to N3, and a third distance measurement value D3 is detected. A weighted average of the second distance measurement value D2 and the third distance measurement value D3 is obtained according to the number of accumulating operations N2 and N3, whereby the distance to the object is determined.

Abstract: A method of determining the planar inclination of a surface is disclosed. Each of three lasers positioned within a sensor body are modulated with different sine wave frequencies based on stored values within a wave-table by superimposing onto the emitted light beam a respective sine wave frequency. The light beam is scattered from each laser onto a respective position sensitive detector after being emitted onto a surface to be analyzed. The light beam is then demodulated by producing electrical signals from each respective position sensitive detector and integrating the electrical signals and calculating the planar inclination on the surface based on demodulated values.

Abstract: A process for determining the distance (D) between a distance sensor and an object. A transmitter sends wave pulses with a predetermined first frequency fb 1 and the wave pulses reflected by the object are received by a receiver and are directed in the form of an analog electrical incoming signal to an A-D converter. The latter scans the incoming signal with a second frequency f2 with f2>f1 and converts it into a digital signal Z(t) which is evaluated for determining a distance value (D) in the following manner: a) Evaluation of the digital signal Z(t) for determining a first wave pulse propagation time (T1); b) k-fold repetition of the step a) for determining the total k wave pulse propagation times (T1, T2, . . . , Tk); c) Calculation of a mean wave pulse propagation time (T=(T1+T2+ . . . +Tk)/k); and d) Calculation of the distance value (D) in accordance with D−v=T/2.

Abstract: A plastic optical fiber continuous optical amplifier for continuously amplifying signal lights includes an exciting light tube with a double tube structure formed of an inner tube and an outer tube, and a plastic optical fiber (POF) coaxially provided inside the inner tube of the exciting light tube. The POF includes a core having an induced emission material therein and a larger refractive index, and a clad for holding the core and having a smaller refractive index than that of the core. The core and the clad are coaxially provided to the POF. It is preferable that electrodes of the exciting light tube have a ring shape to effectively excite.

Abstract: The present invention relates to a distance measuring apparatus which computes the distance from the apparatus to a target by measuring a period of time from when pulse light is emitted toward the target until a reflected component from the target is received. This apparatus comprises a structure for enabling accurate distance measurement by comparing a result of measurement concerning measurement pulse light emitted into a measurement optical path and a result of measurement concerning reference pulse light emitted into a reference optical path. In particular, this apparatus specifies, as the reflected pulse light from the target, the reflected component of the measurement pulse light initially detected after the measurement pulse light is emitted, and adjusts light quantity such that the light quantity of the initially detected reflected component coincides with that of the reference pulse light.

Abstract: A laser survey instrument, which comprises at least a main unit for emitting a laser beam and an object reflector for reflecting the laser beam from the main unit toward the main unit, whereby said main unit comprises an emitter for emitting the laser beam, a rotating unit for rotating and scanning the laser beam, a tilting mechanism for tilting the laser beam at an arbitrary angle at least in one direction with respect to a horizontal plane, a rotating angle detector interlocked with the rotating unit and for detecting irradiating direction of the laser beam, a reflection light detector for detecting reflection light from the object reflector, and an alignment display unit for detecting a deviation of direction with respect to the object reflector and a deviation of tilt angle based on a signal from the reflection light detector and for obtaining information on the deviation of direction or the tilt angle, the laser beam emitted from the main unit is irradiated to scan, the center of the object reflector is

Abstract: A rangefinder apparatus, which projects light toward a range-finding object, detects light reflected from the range-finding object, and measures the distance to the range-finding object according to a position where the light is detected, includes a step-up regulator for raising the power source voltage of a battery; a step-down regulator for receiving the raised voltage outputted from the step-up regulator and outputs a depressed voltage lower than the raised voltage; an autofocus integrated circuit actuated upon receiving the depressed voltage, for outputting a signal corresponding to the distance to the range-finding object according to the signal from a light-detector; and a stabilizing capacitor, connected between a location near a power terminal of the integrated circuit receiving the depressed voltage and a location near a grounding terminal of the integrated circuit, for stabilizing the depressed voltage.

Abstract: An integrated system generates a model of a three-dimensional object. A scanning laser device scans the three-dimensional object and generates a point cloud. The points of the point cloud each indicate a location of a corresponding point on a surface of the object. A first model is generated, responsive to the point cloud, that generates a first model representing constituent geometric shapes of the object. A data file is generated, responsive to the first model, that can be inputted to a computer-aided design system.

Abstract: Dithered-edge sampling (DES) enables ultra-wideband measurement of terahertz pulses (far infrared electromagnetic pulses) using photoconductive antennas. The terahertz pulse is sampled by first passing it through a triggered photoconductive attenuator whose fast attenuation edge (limited only by the duration of the optical gating pulse) is dithered in time. A slow photoconductive receiver then measures the component of the terahertz electric field that is modulated at the dither frequency. The current through the photoconductive element constituting the receiver passes through a locking amplifier which may be operated at dither frequency. When used alone, the receiver blurs the measured terahertz pulse width. However, the increased time resolution provided by DES enables measurement of source-limited terahertz pulse widths. In addition, DES may be used to make direct measurements of a photoconductive receiver's temporal response.

Abstract: The invention provides a sensor for measuring the distances to a medium and/or the physical properties thereof, including a housing; at least one pair of optical fibers, each having an input end portion and an output end portion, the input end portion of a first fiber being connectable to a source of light and the output end portion of a second fiber being connectable to light intensity measuring means; a sensor head, including the input end portion of the second optical fiber and the output end portion of the first optical fiber affixedly located at least in proximity to each other; each of the output end portion of the first fiber and input end portion of the second fiber having an axis and a rim, the rims being cut at an angle &thgr; with respect to the axis and the axes forming an angle &agr; therebetween, and wherein, upon operation, the light emerging from the output end portion of the first fiber impinges on a surface of a medium at an angle of incidence &bgr;, and wherein &bgr;=ƒ(&agr;,&th

Abstract: There is provided an optical amplifier for reducing the optical output power difference and/or obtaining high output power across a wide wavelength band. The optical amplifier comprises a plurality of optical amplifier units connected in two or more stages. At least one of the optical amplifier units comprises a first optical component of a single input and N outputs that has an optical-demultiplexing function, and P units of optical amplification means for the individual amplification of light that is output from P (where 1≦P≦N) output terminals selected from the N (integer) output terminals of the first optical component. Second optical components are provided to the input side of the first optical component or between the output side of the first optical component and the input side of the optical amplification means.