Abstract: A device and method for measuring moving material includes a processor and operating software associated therewith; a light source for emitting at least two polarized light beams in a manner wherein the beams cross thereby creating an interference region and generate a set of fringes; a sensor aligned relative to the interference region wherein the fringes have a predetermined orientation to the directional movement of the material and wherein the sensor is operably equipped to receive scattered light emanating from the interference region and provide a time varying signal to the processor such that the processor can manipulate and convert the signal to speed and distance and a polarizing filter operably associating a polarizing filter with one of the sensor and the emitting means in a manner to substantially preclude reflected polarized light from the interference region back to one of the sensor and the emitting source.

Abstract: A laser radar system using collocated laser beams to unambiguously detects a range of a target and a range rate at which the target is moving relative to the laser radar system. Another aspect of various embodiments of the invention may relate to a laser radar system that uses multiple laser radar sections to obtain multiple simultaneous measurements (or substantially so), whereby both range and range rate can be determined without various temporal effects introduced by systems employing single laser sections taking sequential measurements. In addition, other aspects of various embodiments of the invention may enable faster determination of the range and rate of the target, a more accurate determination of the range and rate of the target, and/or may provide other advantages.

Abstract: A laser radar system using collocated laser beams to unambiguously detects a range of a target and a range rate at which the target is moving relative to the laser radar system. Another aspect of various embodiments of the invention may relate to a laser radar system that uses multiple laser radar sections to obtain multiple simultaneous measurements (or substantially so), whereby both range and range rate can be determined without various temporal effects introduced by systems employing single laser sections taking sequential measurements. In addition, other aspects of various embodiments of the invention may enable faster determination of the range and rate of the target, a more accurate determination of the range and rate of the target, and/or may provide other advantages.

Abstract: Methods are disclosed wherein the structural health of a civil structure, such as, but not limited to, a bridge or the like is measured by electronic distance measurement from a plurality of stable locations to a plurality of cardinal points on the structure in a methodical manner. By measuring the coordinates of the cardinal points, the dynamic and long-term static behavior of the structure provide an indication of the health of the structure. Analysis includes; comparison to a Finite Element Model (FEM), comparison to historical data, linearity, hysteresis, symmetry, creep, damping coefficient, and harmonic terms.

Abstract: A tracking type laser interferometer that detects displacement of a retroreflector 300 being an object to be measured by utilizing interference of a laser beam 102 irradiated onto the retroreflector 300 and reflected by the retroreflector 300 in the returning direction, and carries out tracking by means of a two-axis turning mechanism 240 using displacement in the position of the optical axis of the laser beam 102; the same tracking type laser interferometer, includes; a light irradiator 600 that emits a fan-shaped laser light 602 that is fan-shaped including the optical axis of the laser beam 102, is interlocked with turning movements of the two-axis turning mechanism 240 around an axis orthogonal to the center axis of the corresponding fan shape; and a light receptor 620 that has a specific positional relationship with the retroreflector 300 or the light irradiator 600 and receives the fan-shaped laser light.

Abstract: A method is disclosed whereby a laser-based spherical coordinate measurement system is dynamically calibrated. A mechanical oscillator, such as, but not limited to, a Foucault pendulum is used to generate periodic motions which can be fitted to Fourier series models. The residuals between the experimental measurements and the model can provide information which can be used to calibrate the instrument. The calibration information is used to augment the ASME B89.4.19-2006 standard to improve sensitivity to cyclic errors and include the servo systems.

Abstract: Methods and apparatus are provided for integrating various optical components onto a planar substrate using a single semiconductor material system to produce an accelerometer. A light beam is generated on the semiconductor optical accelerometer. The light beam is split to form two light beams using a multimode interference (MMI) coupler. One of the two light beams that is formed is directed towards a reference mirror and the other is directed towards a flexured mirror. The flexured mirror moves as a result of acceleration and thereby reflects the light beam with a different light beam characteristic. The light beams are combined by the MMI coupler to produce an interference light beam. A microprocessor measures acceleration based on the differences in light beam characteristics of the reflected light beams. Along the optical path light beam detectors measure various beam characteristics. The microprocessor accounts for characteristics measured by the detectors when computing acceleration.

Abstract: A tracking-type laser interferometer in which a pattern emission control unit controls a changing mechanism such that light is emitted along a predetermined pattern when judged by a first judgment unit that at least one of received-light amounts at first and second light reception units is not greater than a first threshold value. A tracking control unit causes the changing mechanism to keep track of a retro reflector when judged by a second judgment unit that both of the received-light amounts at the first and second light reception units are greater than second threshold values during a time period in which the pattern emission control unit controls the changing mechanism for the emission of light along the pattern. The interferometer emits light along the pattern to search for the retro reflector upon losing sight thereof. Upon detection, the interferometer can keep track of the reflector again and resume measurement.

Abstract: The invention relates to a method for interferometric absolute distance measuring by a frequency modulation electromagnetic radiation on at least one measurable target and for subsequently receiving a retransmitted radiation with a heterodyne mixture, wherein the radiation is guided in a parallel direction via a reference interferometric length. In such a way, a first digitized interferogram of the radiation retransmitted by the target and a second digitised interferogram of the radiation guided on the reference length are obtainable at a reception. According to phase progression data of the second interferogram, a virtual interferogram or a phase progression thereof is synthesized and the distance determination is carried out by comparing the progression face data of the first interferogram with the progression face data of the virtual interferogram.

Abstract: Provided are systems and methods for performing high-precision length measurement. One such system includes: an optical receiver, configure to receive a reflected optical pulse from a target; an optical combiner, configured to generate a combined optical pulse using the reflected optical pulse and a reference optical pulse; and a signal analyzer configured to determine a distance to the target using a depth of modulation value of the combined signal. A method as disclosed herein includes the steps of determining a first length component of a combined optical signal using a depth of modulation value and determining a second length component of the combined optical signal using a modulation period value.

Abstract: Provided are systems and methods for performing high-precision length measurement. One such system includes: an optical receiver, configure to receive a reflected optical pulse from a target; an optical combiner, configured to generate a combined optical pulse using the reflected optical pulse and a reference optical pulse; and a signal analyzer configured to determine a distance to the target using a depth of modulation value of the combined signal. A method as disclosed herein includes the steps of determining a first length component of a combined optical signal using a depth of modulation value and determining a second length component of the combined optical signal using a modulation period value.

Abstract: An optical-axis deflection type laser interferometer includes a reference ball serving as a measurement reference, a retroreflecting means disposed at an object to be measured, a laser interferometer length measuring apparatus outputting a measurement value between the apparatus and the retroreflecting means, and a rotational mechanism that rotates a beam projected from the laser interferometer length measuring apparatus around the reference ball. The laser interferometer additionally includes a displacement gauge that measures an error caused by a relative motion between the reference ball and the laser interferometer length measuring apparatus, and a rectilinear movement mechanism that displaces these in a direction of an optical axis of a measurement beam with respect to the reference ball while maintaining a relative positional relationship between the laser interferometer length measuring apparatus and the displacement gauge.

Abstract: An information processing method using a terminal apparatus, including: applying light with a concentric ring-like interference fringe pattern on one of subjects by using a pointer provided in the terminal apparatus; detecting the interference fringe pattern by using a detector; calculating an optical axis of the pointer on the basis of a detection signal obtained from the detector; specifying attribute information of the subject on the basis of arrangement information of the subject intersected by the optical axis in the condition that arrangement information of the subjects and attribute information of the subjects are stored in a storage device in advance while the arrangement information of each subject and the attribute information of the subject are associated with each other; and displaying the attribute information of the specified subject on the terminal apparatus.

Abstract: An optical-axis deflection type laser interferometer includes a reference ball serving as a measurement reference, a retroreflecting means disposed at an object to be measured, a laser interferometer length measuring apparatus that outputs a measurement value according to an increase or a decrease in distance between the apparatus and the retroreflecting means, and a rotational mechanism that rotates a beam projected from the laser interferometer length measuring apparatus around the reference ball. The thus structured laser interferometer measures a distance between the laser interferometer and the retroreflecting means that makes an optical axis of an outgoing beam projected from the laser interferometer length measuring apparatus mounted on the rotational mechanism and an optical axis of a return beam returned to the laser interferometer length measuring apparatus parallel to each other, based on center coordinates of the reference ball.

Abstract: At least one self-powered light source is mounted on the tail rod of a BOP to provide an indication of the position of the ram of the BOP. The light source moves back and forth with the ram actuating piston of the BOP. Opposite the light source is a light-receiving lens. The lens is coupled by optical fiber to a optical to electrical converter. As the BOP is actuated, the tail rod moves, thereby moving the light source to a position adjacent a different lens. The lens which is now positioned adjacent the light source sends a light signal to its respective converter, thereby indicating the position of the tail rod and thus to ram of the BOP.

Abstract: An external cavity laser has an external cavity that is formed between a target surface and a laser diode facet located farthest from the target surface. A chromatic dispersive element is disposed in the external cavity, and focuses light from the laser diode such that one wavelength is focused at a focal spot on the target surface. Light reflected from the focal spot on the target surface is the predominant wavelength coupled back into the laser waveguide, which provides a feedback signal that determines the oscillation wavelength of the laser diode. The laser diode therefore outputs a well-defined wavelength of light which corresponds to the distance between the chromatic dispersive element and the target surface.

Abstract: An interferometer which incorporates a single mode VCSEL to facilitate miniaturization through integration of parts. The interferometer includes a beam splitter for partially reflecting and transmitting light; a single mode vertical-cavity surface-emitting laser for generating a beam of light perpendicular to a wafer; a first mirror fixedly perpendicular to the first path to reflect the portion of light reflected from the beam splitter; a second mirror movably arranged along the second path to reflect the beam portion transmitted through the beam splitter. A photodetector arranged along the second path detects the beam portion reflected from the first mirror and transmitted again through the beam splitter and the beam portion reflected from the second mirror and reflected again from the beam splitter to locate the second mirror based on an interference fringe created by a difference in the paths between the two beam portions.

Abstract: Systems and method for determining, based on a gray scale image, focus of an imaging system. A method of this invention includes the steps of: a) acquiring a gray scale image of a test target, b) binarizing the acquired gray scale image, c) analyzing the binarized acquired image, d) adjusting focus of acquisition optics of the imaging system, and e) repeating steps a) through d) until a substantially maximum number of line pairs of a number of groups of line pairs of the test target is obtained, wherein each group from the number of groups of line pairs has a predetermined spatial frequency.

Abstract: Multidirectional retroreflectors and methods of reflecting light beams from multiple directions are provided. The multidirectional retroreflectors utilize a four-mirror retroreflector with a common virtual reflection point.

Abstract: A method, apparatus, and computer readable medium are provided for creating a quantitative, three-dimensional representation of a surface of a human subject. Data representing a physical appearance of a human subject is gathered using inverse synthetic aperture radar. A source signal is directed toward the human subject as the target rotates through a range of motion and a return signal is collected. The returned signal is transformed into a quantitative representation of the surface data. The quantitative representation can be added to an archive or can be checked against an archive to determine if the human target is indexed in the archive.

Abstract: A laser tracking interferometric length measuring instrument has a laser source and a tracking articulating optical lever provided on an optical path of an interferometric optical system. To track a retroreflector, the optical lever reflects a laser beam at the retroreflector, which reflects the beam back to the optical lever. This beam is reflected onto a quadrant photodiode. An attitude control means is used to control the attitude of the optical lever so that the laser beam reflected by the optical lever falls on the neutral point of the photodiode.

Abstract: A bulge testing system (10) for testing the material properties of a thin film window (14) using a Michelson interferometer (18) that generates an interference pattern (32) having fringes (34) and nodes (36) that move as the thin film window is inflated or deflated. The bulge testing system includes a fringe counting module (82), an analysis module (114) and an output module (88). The fringe counting module allows a user to interactively select from an image of the interference pattern one or more sampling regions (30) in which the user interface will count fringes. The analysis module allows a user to interactively change the location of maxima/minima indicators (116) in the event that noise in the image causes the analysis module to incorrectly determine the locations of the fringes and nodes. The output module automatically calculates material properties and provides test results to an output file and/or a results window (168).

Abstract: A method and arrangement are disclosed for increasing the depth contrast in microscope imaging. The method and implementation described can be designated as structured illumination for generating quasi-confocal optical sections. In implementing the method, a grating structure located in the field diaphragm plane of a microscope, the object plane and the TV intermediate image plane of a microscope are arranged confocally. The term “confocally” refers to the fact that the grating, object and the intermediate image plane are positioned on optically conjugate planes. By this arrangement, the grating structure is projected in the object plane of the microscope and the object which is structured in this way is imaged in the TV intermediate image plane of the microscope by the optical system following it. Optical sections are generated by calculating the modulation depth of the structured object.

Abstract: A distance-measuring device for measuring the distance to an object (M) which comprises (i) a frequency-controlling means (11A) which outputs a frequency-control signal whose frequency is changing, (ii) a transmitting means (12A) which sends out an electromagnetic wave whose frequency is the same as the frequency of the frequency-control signal, (iii) a detecting means (13A) which is provided between the transmitting means (12A) and the object (M), detects the amplitude of a standing wave formed between the transmitting means (12A) and the object (M), and outputs an amplitude signal corresponding to the detected amplitude, and (iv) a signal-processing unit (14A) which forms a frequency-amplitude function representing the relation between the frequency of the frequency-control signal and the value of the amplitude signal and calculates the distance between the detecting means (13A) and the object (M) by using the period of the frequency-amplitude function.

Abstract: A positioning system including a sensor, a drive sequencer and an actuator. The sensor senses the actuator position and provides position signals to drive the sequencer which responsively computes and drives the actuator in open loop moves containing dwell intervals of position. The actuator positions a mirror or other load means to reflect an optical beam as desired. Either preprogrammed or non-repeating sequences of actuator stopping positions can be synchronized with a laser. During dwell times, mirror position accuracy better than 10 microradians is suitable for tuning CO2 pulse burst or CW lasers.

Abstract: A laser based tracking unit communicates with a target to obtain position information about the target. Specifically, the target is placed at the point to be measured. The pitch, yaw and roll of the target, and the spherical coordinates of the target relative to the tracking unit are then obtained. Then additional information regarding a probe attached to the target reconciled with the above determination to determine a position of a probe tip. The target can be, for example, an active device incorporated into a moveable device such a remote controlled robot.

Abstract: A laser tracking interferometric length measuring instrument has a laser source and a tracking articulating optical lever provided on an optical path of an interferometric optical system. To track a retroreflector, the optical lever reflects a laser beam at the retroreflector, which reflects the beam back to the optical lever. This beam is reflected onto a quadrant photodiode. An attitude control means is used to control the attitude of the optical lever so that the laser beam reflected by the optical lever falls on the neutral point of the photodiode.

Abstract: A laser tracking interferometric length measuring instrument has a laser source and a tracking articulating optical lever provided on an optical path of an interferometric optical system. To track a retroreflector, the optical lever reflects a laser beam at the retroreflector, which reflects the beam back to the optical lever. This beam is reflected onto a quadrant photodiode. An attitude control means is used to control the attitude of the optical lever so that the laser beam reflected by the optical lever falls on the neutral point of the photodiode.

Abstract: A goniometer includes a base, a compound member supported by the base, a light-directing element operably mounted on the compound member, optically connected to a coherent light source, and disposed toward an optical filter, a first actuator disposed along a first axis and operably coupled to the base for translating the light-directing element along a first arcuate path disposed in a first plane; and a second actuator disposed along a second axis and operably coupled to the compound member for translating the light-directing element along a second arcuate path disposed in a second plane, wherein the first plane is orthogonal to the second plane, and wherein the first and second axes are co-planar, for directing coherent light at an angle that is normal to the optical filter.

Abstract: A laser based tracking unit communicates with a target to obtain position information about the target. Specifically, the target is placed at the point to be measured. The pitch, yaw and roll of the target, and the spherical coordinates of the target relative to the tracking unit are the obtained. The target can be, for example, an active device incorporated into a moveable device such a remote controlled robot.

Abstract: A means for overcoming perspective foreshortening in the receiver of a diffraction range finder by use of chirp diffraction grating 121. In a diffraction range finder, a diffraction grating with variations in pitch such that the displacement of higher-order diffraction images in a receiver are separated from their associated zero-order image by an arbitrary displacement with respect to an arbitrary target distance. A system for ranging a target comprising a variable pitch grating 122 and a receiver 200 of the diffraction images formed by said grating.

Abstract: A three-dimensional image is derived from two-dimensional images. At least one of the two-dimensional images has a predetermined number of pixels. Depth measurements are derived from the two-dimensional images. The number of derived depth measurements is substantially equal to the predetermined number of pixels. The three-dimensional image is derived from the two-dimensional digital images and the depth measurements.

Abstract: A novel three dimensional surface contouring method has been developed based on the fall-field fringe projection technique. A digital video projection system is used to project digitally created fringe patterns onto the object. The fringe pattern distorted by the geometry of the object surface is then captured by a high resolution CCD camera. To increase contouring resolution, purely software-based digital phase shifting technique is used, which eliminates the need for accurate positioning systems in the traditional phase shifting methods. The surface is reconstructed by applying the phase wrapping and unwrapping algorithms.

Abstract: A laser tracking interferometric length measuring instrument has a laser source and a tracking articulating optical lever provided on an optical path of an interferometric optical system. To track a retroreflector, the optical lever reflects a laser beam at the retroreflector, which reflects the beam back to the optical lever. This beam is reflected onto a quadrant photodiode. An attitude control means is used to control the attitude of the optical lever so that the laser beam reflected by the optical lever falls on the neutral point of the photodiode.

Abstract: The invention relates to an incoherent Doppler laser detection and ranging system of the Lidar type comprising an emission laser and a receiver device including at least one telescope, an edge filter, and processor means responsive to the power PT transmitted by the filter. The processor means has data inputs relating to the power PT and to the power PR and outputs a normalized signal &Dgr;PN, where: Δ ⁢   ⁢ P N = P T - P R P T + P R PR designating the power reflected by the edge filter.

Abstract: Multidirectional retroreflectors and methods of reflecting light beams from multiple directions are provided. The multidirectional retroreflectors utilize a four-mirror retroreflector with a common virtual reflection point.