Abstract: A level of received light detected by a light-receiving means (R) is given to both an indication controller (11) and a transmitter (13). The indication controller (11) obtains a flashing frequency corresponding to the given received light level, and flashes an LED (12) at the frequency obtained. The received light level transmitted from a transmitter (13) is demodulated and decoded in a receiver (4) and then given to an indication controller (3). The indication controller (3) obtains a flashing frequency corresponding to the given received light level, and flashes an LED (2) at the frequency obtained. Thus, the operator can recognize the received light level readily and reliably.

Abstract: A device for aligning and measuring a hollow, rotatable bore includes a laser beam source within a housing having an aperture in its front face for passing the beam. The housing is mounted at one end of the extruder bore to project the beam through the bore to be detected by a target at the opposite end. The diameters of the aperture and bore are concentric and the laser beam defines an axis that is alignable with the axis of rotation of the rotatable member, using target signals, by vertical and horizontal displacement with micrometers disposed on the rear face of the laser housing. Various arrangements for mounting the housing on the extruder are disclosed. The target includes a sensing cell in a housing mounted in an adapter with four balls disposed on its periphery 90.degree. apart.

Abstract: A lead pipe configuration for use in an underground piping device wherein a succession of lead pipes are propelled in a forward direction to guide pipeline lay down are provided with ring-shaped light shields in at least some of the lead pipes so that such light shield can block at least some of the light projected rearwardly from a direction correction head at a foremost tip of the lead pipe configuration that would interfere with axially directed incident light that is to be detected by a transit at the rear of the configuration, this detection being used to determine if lead pipe configuration direction error is present and if so that it be corrected. The lead pipes also can have a high light absorption coating such as a resin on the inner lead pipe surfaces to absorb reflected light that otherwise could interfere with proper light detection.

Abstract: A split-field pupil plane determination apparatus (10) having a wedge assembly (16) with a first glass wedge (18) and a second glass wedge (20) positioned to divide a laser beam (12) into a first laser beam half (22) and a second laser beam half (24) which diverge away from the wedge assembly (16). A wire mask (26) is positioned immediately after the wedge assembly (16) in the path of the laser beam halves (22, 24) such that a shadow thereof is cast as a first shadow half (30) and a second shadow half (32) at the input to a relay telescope (14). The relay telescope (14) causes the laser beam halves (22, 24) to converge such that the first shadow half (30) of the wire mask (26) is aligned with the second shadow half (32) at any subsequent pupil plane (34).

Abstract: Automatic alignment correction of the setting angles of mirrors in a laser robot is achieved by mirrors 2c,2d, and 2e being linearly displaced a predetermined distance in a sequence from one closer to a laser oscillator 1 to another. At the same time, a locus of displacement of a spot S on a position sensor during movement of a particular mirror is detected by the position sensor 9 disposed in front of a laser output nozzle 4. An error in the setting angle of a mirror preceding to the particular mirror having been moved is computed on the basis of the detected value, so as to perform angular correction relative to the particular mirror by motors 11a and 11b. In one embodiment, mirror 2e is rotated about the C-axis. When the incident position of the laser beam is offset from the center of rotation of the mirror 2e, the spot S obtained in the position sensor 9 will move in a circular path.

Abstract: An apparatus determines the position of an object with respect to a reference coordinate system. Preferably, the apparatus includes a target attached to the object, the target moves within a defined region and has a surface with a first pattern thereon. A projection device projects a second pattern upon the surface. A sensing device provides an image signal indicative of the target surface including the first pattern and the second pattern. An analyzer receives the image signal and determines the position of the object based on the position of images of the first pattern and the second pattern.

Abstract: A guidance system and method for keeping a tunnel boring, machine continuously on a plan line. The guidance system requires no machine operator calculations and provides the boring machine operator with a graphic display of past, present and projected positions of the boring machine from a horizontal and vertical perspective. The system uses a laser beam transmitter placed to the rear of the tunnel boring machine along with a front opaque target with a horizontal and vertical cross-hair and a rear transparent target with a horizontal and vertical cross-hair. The front and rear targets are disposed on the front and the rear of the boring machine. Also, an on-board programmable computer is installed on the boring machine for imputing data as to horizontal offset and vertical offset readings from the front and rear targets as the boring machine advances forward. Typically the boring machine moves forward in increments of four feet with offset readings taken by the operator after each increment.

Abstract: A method of testing a laser target designator, in which an aperture in the field of view of the laser target designator has one side facing the target image detector and the laser, a beam image detector faces an opposite side of the aperture and is aligned with the opening thereof so that the beam optical axis and the opposite side of the aperture are in a field of view of the beam image detector, both sides of the aperture being illuminated, and beam video processor obtains a test video image from the beam image detector and computes a centroid of the aperture in the test video image and a centroid of the laser beam in the test video image, the displacement of these centroids being a measure of the static error while relative movement of them during dithering of the optical path from the laser target designator is a measure of the dynamic error.

Abstract: The present invention relates to the efficient and cost-effective generation of two co-linear laser beams for the purpose of alignment, particularly in the construction industry. The unequal divergence of the light from a typical laser diode produces a beam of elliptical cross section. Two roughly equal co-linear beams of light can be generated by reflecting the collimated elliptical beam from two mirror surfaces at 90.degree. to each other or a single element dividing the elliptical beam in two. Techniques are described for generating offset parallel beams, and for correcting for inherent knife-edge diffraction effects due to division of the beam.

Abstract: A device for aiding in the cross-hair alignment of the reticle of a gun-mounted telescopic sight wherein the gun includes at least one scope base for securing the telescopic sight. The device includes a light source for projecting a beam of light against a surface. The light source is mounted to the scope base of the gun. The projected light beam is modified to form a reference line which may be viewed through the telescopic sight. The projected reference line is automatically aligned with the barrel axis of the gun. One of the cross-hairs of the reticle of the telescopic sight may be compared with the aligned projected reference line and adjusted accordingly to align the cross-hairs with the barrel axis of the gun.

Abstract: A measurement referencing and transferring technique includes locating a platform base at a working location, mounting a sighting mechanism having a sighting axis on the platform base, and sighting a selected point on a first object in a given direction from the platform base by adjusting the position of the platform base relative to the working location thereby directing the sighting axis of the sighting mechanism toward the first object, and aligning the axis incident with the selected point on the first object. A reference point is then marked on a second object in a direction opposite the given direction from the platform base, by observing along the aligned sighting axis in the direction away from the first object, and defining the reference point as that point on the second object with which the sighting axis is incident. A measurement associated with the selected point on the first object is determined by referring to the reference point marked on the second object.

Abstract: The boresight is comprised of a caliber rod having extending therefrom a reflecting member. The reflecting member has at least one reflecting surface; the reflecting surface being in either a fixed substantially perpendicular orientation to a longitudinal axis through the rod, or able to be adjusted to any desired angle with the axis of the rod. The rod is adapted to be removably slidable, and rotatable, within a muzzle of a bore of a weapon, while it is also constructed to fit snugly within the bore. The boresight may also comprise a beam splitter mirror for gathering light into the aiming device of the weapon. The muzzle of the weapon and the aiming device of the weapon are aligned when the aiming device or reticle (cross-hairs) of the aiming device and the reflection of the aiming device or reticle of the aiming device seen on the reflecting member coincide.

Abstract: A beam axis adjusting method of a laser robot including the steps of splitting a visible laser beam traveling along a laser beam pathway within the robot unit of the laser robot into a first laser beam traveling further along the laser beam pathway and a second laser beam traveling outside the robot unit, receiving the second laser beam by a target plate made of a semitransparent plate and mounted on the robot unit to form a light spot Sp on the front surface of the target plate, adjusting a relevant reflecting mirror unit disposed in the robot unit for the adjustment of the beam axis of the laser robot, and visually observing the light spot Sp from behind the back surface of the target plate while the relevant joint of the robot unit is in motion.

Abstract: An apparatus determines the position of an object with respect to a reference coordinate system. Preferably, the apparatus includes a target attached to the object, the target moves within a defined region and has a surface with a first pattern thereon. A projection device projects a second pattern upon the surface. A sensing device provides an image signal indicative of the target surface including the first pattern and the second pattern. An analyzer receives the image signal and determines the position of the object based on the position of images of the first pattern and the second pattern.

Abstract: An improved self centering guide pipe axis laser guide is based on the use of three parallel links spaced 120 degrees apart which are engaged to be expanded or contracted. When expanded the links contact the inside diameter of the pipe which accordingly establishes the center axis of the pipe. The links are actuated for expansion or contraction by mounting a spring base spider element in association with a spider lever element on a smooth pipe housing, wherein the movement of the spring base spider element and the spider lever element is controlled by thumbscrews on each of the elements, the smooth pipe housing containing within, the power supply and laser module, and a removable switch assembly at the rear enabling easy access to the batteries. The laser guide can readily be withdrawn from the pipe by attaching a tether line to the front end and levels for determining the slope are mounted in slots in both the front and rear spider elements.

Abstract: The parallelism of two nominally parallel surfaces is determined by placing a planar reflector (50) on one surface and a cube beam splitter (52) on the other surface. The reflector is placed to reflect light in a direction normal to the plane of the reflector. The cube beam splitter is placed to reflect part of the light striking a first face (54) back in the opposite direction. The cube beam splitter also reflects part of the incident light towards the reflector so that the reflector reflects the light back to the cube beam splitter, causing the light to exit the first cube beam splitter face. An autocollimator (10) is provided to direct a beam of light (24) into the first face (54) of the cube beam splitter (52) and to display the divergence between the first and second reflected beam portions, the divergence corresponding to the degree of non-parallelism between the two surfaces.

Abstract: A bore sighting apparatus and method includes a light source contained within a housing, which is in the form of a stepped cylindrical insert placed in the firing chamber of the firearm. The housing is in the form of a series of interconnected stepped cylindrical portions corresponding to the firing chambers of different calibers of firearms, with the largest portion being located at the rear of the firing chamber. Light is projected from the housing through the bore of the barrel and through the muzzle to a target placed at a pre-established distance from the muzzle. Calibrated points are marked on the target; and the sights of the firearm are adjusted to the calibrated points to effect the bore sighting of the firearm for a specific range.

Abstract: An apparatus for adjusting optical axes of lenses in a lens system detects disagreement of the optical axes, adjusts the position of a subject lens, and fixes the adjusted lens to a lens frame. Parallel light beams constituted by a central and circular peripheral beams are projected to the lens system and form beam spot images on a light receiver. Disagreement of the optical axes is detected as a positional difference between the central beam spot and the centroid of the peripheral beam spots. The subject lens is moved by an adjustment device based on the difference. Adjustment is achieved by repeating the process automatically, and the lens is fixed at the position after the adjustment.

Abstract: A firearms sight alignment system is provided which allows for the use of a collimated beam light source attached to a housing which binds the light beam with the direction of a firearm barrel. This light source thus provides a point at which to adjust the sighting apparatus of the firearm while the light source is shining upon an object some distance in front of the firearm barrel. The light source is aligned by a simple housing mechanism mounted to either a mandrel which is inserted into the bore of the firearm barrel or from a bracket attaching the light source to the barrel and alignment therewith.

Abstract: A reflective collimator adjusts an input light beam producing an output light beam parallel to the input light beam. The input light beam is reflected and focused by a first reflector to a second reflector, then reflected from the second reflector to a third reflector, and reflected from the third reflector to a fourth reflector, and finally reflected and focused from the fourth reflector to a focus point.

Abstract: A laser beam receiver including a transparent disc and a mirror arrangement which are fastened on a base element. A light spot formed on the disc by a laser beam may only be seen optimally, particularly if the distance between the laser device and the laser beam receiver is so great that the laser beam arrives only faintly, if the observer's angle of view lies in the axial extension of the laser beam. The mirror is so arranged that this angle of view lies exactly in the axial extension of the laser beam. The range of action of the laser device is thus expanded in a simple and inexpensive manner.

Abstract: Apparatus for boresighting firearms which utilizes a number of commercially available laser gun sights as a light source. The system includes both fixed and adjustable bore adapters as well as fixed and adjustable laser sight mounts. Fixed bore adapters are designed for specific calibers. Adjustable bore adapters will function over a wide range of calibers. Fixed laser sight mounts will work only for laser gun sights of a specific diameter. Adjustable laser sight mounts will function with laser gun sights of any diameter. Fixed laser sight mounts may be utilized with adjustable bore adapters and fixed bore adapters may be used with adjustable laser sight mounts.

Abstract: A fixture automatically aligns a laser transmitter bolted to a rifle. A case is horizontally oriented and a hinged end cover is swung upwardly to reveal a control unit. The barrel of the rifle is supported on a weapon rest mounted to the base unit and the trigger guard or clip receptacle is mounted in a vise on a sliding rack inside the case. The vise has knobs for adjusting the azimuth and elevation of the weapon, thereby permitting the soldier to aim at a target reticle. An optics unit is mounted on a forward portion of the base unit and includes a lens and a beam splitter which is transparent to infrared light from the laser transmitter but reflective to visible light. The illuminated target reticle is mounted inside the optics unit. The beam splitter is positioned forward of the lens and is angled at forty-five degrees to project the image of the target reticle through the lens at infinity.

Abstract: An optical parking alignment system that includes at least one projector located on a vehicle for projecting a respective image forwardly of the vehicle, whereby alignment of the vehicle is indicated when each respective image is in focus on a screen disposed in front of the vehicle. The projector cam comprise a transparency and an imaging lens, or a hologram and a narrowband light source.

Abstract: Methods of compensating for errors in a laser pointing device, particularly for use in three-dimensional applications, by accurately controlling the angle that the laser beam makes in space.A method for rectifying a laser pointing device that aims a laser beam by deflecting the beam through a plurality of optical deflection devices each directed by a galvanometer controlled by an input. In the method, the laser pointing device is established in an accurate angular relationship to at least four fiducial points. The angular errors internal of the laser pointing device are determined by comparing actual galvanometer inputs to nominal galvanometer inputs, assuming no error in the established angular relationship. The actual galvanometer inputs are those that aim the laser beam at the fiducial points (while recognizing the existence of the internal errors), and the nominal galvanometer inputs are those that would aim the laser beam at the fiducial points assuming no internal errors in the laser pointing device.

Abstract: An alignment mechanism is provided for adjusting the optical center line of scanning beams generated in a ROS system. The collimator lenses which collimates the output of a diode laser source are mounted within a lens barrel. The lens barrel is positioned so as to be biased against the sides of a housing in which the ROS components are located. The barrel has eccentric rings mounted along its circumference which, when rotated, inpart motion to the lens barrel so as to change the center line of the collimated beam output. This provides adjustment of the scan line center line at the image plane.

Abstract: Apparatus for aligning the optical systems of a lamphouse and a movie projector in the form of a laser alignment tool having a single beam laser with a diffraction grating to split the beam into multiple beams and the laser diode module is housed in a cylindrical casing. The diffraction grating splits the single laser into a specific number of beams of equal intensity, consisting of a center beam and each of the beams to either side of it at equal angles. The laser alignment tool has a geared motor with an adjustable speed which rotates the diffraction grating so that each angled beam sweeps a concentric circle with respect to the other beams. The diffraction grating is interchangeable so that the laser alignment tool can be used for lamphouse systems with varying focal lengths or for other applications such as reflector inspection. The motor may be turned on or off while the laser is kept on. The speed of rotation of the beams is controlled by varying the voltage to the motor.

Abstract: Planar light sources are directed at an article on either side of the optical axis so that the trace of each light beam defines a line, on either side of the optical axis, whose form is dependent on the shape of the surface of the article. To determine whether the article is in focus, the distance between the two lines is measured. To determine whether the article is in correct pitch, the distance between each line and the optical axis is measured and compared. To determine whether the article has drifted, the distances between the ends of the lines and the optical axis are measured and compared.

Abstract: This invention relates to a process for measurement of the relative positions of the center-lines of an aperture and of a cylindrical outline of a sample.The process includes the following steps:introducing a calibrated rod into said aperture;performing measurements to define at least a pair of segments representative of the mid-points of the cylindrical outline and of a calibrated rod respectively.The measurements are performed utilizing a light beam which is scanned parallel to the beam in a direction perpendicular to the center-line of the cylindrical outline. This enables measurement of the coaxiality and/or of the concentricity of the center-line of the outline and of the aperture.

Abstract: A noise resistant laser system for machine alignment comprised of a semiconductor laser for producing a narrow collimated beam; a photodetector target for receiving the beam and producing four trains of output pulses which are indicative of the horizontal and vertical displacements of the laser beam from the center of the target; a crystal controlled oscillator for generating pulses at a frequency which is distinguishable from the frequencies of noise generated by industrial power supplies, industrial lighting and their harmonics; a closed loop control circuit for pulsing the laser at the distinguishable frequency; and a sample and hold circuit for sorting out components due to the beam displacement and suppressing components due to the industrial power supplies, industrial lighting and their harmonics. The closed loop control circuit is comprised of an interrupter, a feedback control circuit and a laser current control circuit.

Abstract: A pair of second cameras mounted on a robot are located in front of, and symmetrically with respect to the center of a wheel hub of a vehicle, according to approximate coordinates of the center of the wheel hub calculated from an image of the wheel hub taken by a first camera. Revised coordinates of the center of the wheel hub, a rotational displacement from a standard rotational position of the wheel hub, and a turning angle of the wheel hub toward the right or left with respect to a progressive direction of the vehicle are calculated from the images obtained by the second cameras. A wheel is then automatically mounted to the wheel hub by the robot, according to the results of calculation.

Abstract: Disclosed is an apparatus and method for positioning an electric powered vehicle (34) relative to an electric recharging unit (36) utilizing an optical docking system (10). A first laser emitting diode (12) generates a first visible beam (18) and a second laser emitting diode (14) generates a second visible beam (20). The first visible beam (18) and the second visible beam (20) intersect at an intersection point (22) remote from the electric powered vehicle (34). This intersection point (22) is aligned with the electric recharging unit (36) thereby positioning the electric powered vehicle (34) at a predetermined distance and a predetermined position relative to the electric recharging unit (36).

Abstract: An assembly for use in a laser instrument which produces a plane of laser light by reflection from a cone. The assembly includes a weak focusing lens which improves the control over the planarity of the plane of light produced. Because it is weak, the weak focusing lens can be positioned over a relatively large distance to produce slight changes in the focus of the beam which is reflected to produce the plane of light. Critical, time consuming, and expensive manufacturing requirements can be relaxed, while improved performance results in superior laser instruments.

Abstract: There is disclosed a method and an apparatus for easily controlling the advancing direction of an excavating machine without causing the excavating machine to largely trace in a zigzag way. The direction control is done by the steps of mounting a reflector on a head portion of a shield body so as to receive a light beam directed along an imaginary reference line, mounting a target on a tail portion of the shield body so as to receive the reflected light beam from the reflector, controlling means for correcting the direction so that the reflected light beam may be irradiated at an objective position within the target, and thereby controlling the advancing direction of the excavating machine so that a subjective portion at the front end of the head portion may follow along the reference line.

Abstract: A method and system of alignment of two mechanical members of a mechanical structure, particularly the primary and secondary mirrors (22, 24) of a telescope (20), is provided by a set of auxiliary optical elements (40) disposed on the primary mirror and a corresponding set of detectors (42) disposed on the secondary mirror. The array of detectors corresponds in configuration to the array of auxiliary optical elements so that there is correspondence between positions of auxiliary optical elements with positions of detectors about a common central axis (38) of the two mirrors. A source (44) of light disposed on the axis between the two mirrors illuminates the auxiliary optical elements to develop a set of eight beams, in a preferred embodiment of the invention, which are directed to the optical elements.

Abstract: An apparatus for measuring the deviation from a specific position of a mirror surface, includes an auto collimating system in which a point light source is located at a reference point on a reflecting surface of the mirror surface located at a predetermined correct position. A light emitter emits detecting light onto the point light source from an incident optical axis inclined with respect to a normal of the mirror surface. A position detector measures the deviation of the detecting light reflected by the mirror surface and reciprocally transmitted through the auto collimating system and again reflected by the mirror surface.

Abstract: Primary and secondary mirrors constitute a collimator which permit measurements to be made within a reasonably sized equipment enclosure. An incoming laser beam, from a unit undergoing test, has its light dispersed by an integrating sphere from which radiometric measurements may be made. Further, the output from the sphere passes through an avalanche photo diode for detecting laser beam pulse envelopes. These envelopes may be measured for such parameters as pulse width, and interval. A focal plane array camera is provided to measure boresight deviation from the unit undergoing test.

Abstract: An optical alignment system includes a transmitter of a beam of radiant energy and receiver thereof. Both the transmitter and receiver carry a plurality of light emitting diodes. As the optical alignment between the transmitter and the receiver is altered, the number of diodes which is energized is increased or decreased in response to increasing or decreasing the optical coupling therebetween.

Abstract: A method and apparatus for adjusting the optical alignment of a film projection system of the type having a film gate with a central opening, a lens mount having lenses optically aligned along an optical axis of the lens mount, a light source and a generally ellipsoidal collector for reflecting light from the light source along an optical axis of the collector. The method and apparatus utilize a laser light source which is inserted in the position normally occupied by the lenses and a beam splitter which splits the beam of laser light into a center beam and two inclined side beams. An intercept sheet is temporarily placed in the path of the center beam and reflections of the side beams from the interior surface of the collector to create images of the center beam and the reflected side beams on the intercept sheet.

Abstract: An assembly for use in a laser instrument which produces a plane of laser light by reflection from a cone. The assembly includes a weak focusing lens which improves the control over the planarity of the plane of light produced. Because it is weak, the weak focusing lens can be positioned over a relatively large distance to produce slight changes in the focus of the beam which is reflected to produce the plane of light. Critical, time consuming, and expensive manufacturing requirements can be relaxed, while improved performance results in superior laser instruments.

Abstract: A tool is disclosed for evaluating the alignment of the channel of an endoscope. The tool includes a housing with one end thereof being connectable to the endoscope. The other end of the housing includes an eyepiece. A lens system is provided within the housing for imaging the distal end of the endoscope onto a reticle. The position of the image on the reticle allows the axial alignment of the endoscope channel to be evaluated.

Abstract: A method is disclosed for accurately aligning a shaft in a hole. One application is disclosed for aligning electromagnetic reflectors. An accurately positioned front surface targeted mirror on a predefined reflector axis is used with a reflected laser beam, optical auto-collimation or auto-reflection using an alignment telescope. The mirror is mounted on one end of a shaft which is inserted into a hole of depth l formed through the reflector at the axis, and has formed thereon a reticle at the shaft axis. By aligning the shaft axis with the hole axis in accordance with the invention, extremely accurate alignment of the reflector can be accomplished.

Abstract: Eye alignment is determined by producing a combined iris/retinal image by use of an imaging system. The relative position of the centroid of the pupil and various structures on the retina is indicative of the eye alignment. The eye alignment may be determined by comparing a combined iris/retinal image at the present time with a stored iris/retinal image at a past time. The imaging system may be a laser scanning ophthalmoscope.

Abstract: A target employable for three-dimensionally measuring a position and an attitude occupied by an object such as a space craft or the like while the target is attached to the object as well as a system for enabling the object to be three-dimensionally measured from a measuring point remote from the object by using the target are disclosed. The target includes a mark for indicating positions of four or more different points on a single common plane and a spherical reflector of which the center of curvature is located remote from the common plane.

Abstract: In multi-telescope arrays that comprise multiple telescopes, a beam-combining module, and flat mirrors for directing light beams from the multiple telescopes to the beam combining module, a laser metrology system is used for monitoring various pathlengths along a beam path where deviations are likely. Some pathlengths are defined simply by a pair of retroreflectors or reflectors at both ends. Lengths between pairs of retroreflectors are measured and monitored by laser interferometers. One critical pathlength deviation is related to the displacement of the flat mirror. A reference frame is set up relative to the beam-combining module to form and define the coordinate system within which the positions of the flat mirrors are measured and monitored. In the preferred embodiment, a pair of retroreflectors along the optical axis of the beam-combining module defines a reference frame. A triangle is formed by the reference frame as the base and another retroreflector at the flat mirror as the vertex.

Abstract: A laser diode alignment apparatus and method for an optical scanner which independently minimizes lateral and angular deviation of a laser beam from the scanner axis. The alignment apparatus includes a socket member and a plug member. The socket member includes a cylindrical wall portion, including a circular inner ridge having an inwardly facing spherical surface, and a base portion coupled to the cylindrical wall portion having a rearwardly facing spherical surface and a circular aperture therethrough. The plug member contains the laser diode and includes a cylindrical front end portion including a spherical front edge section, having the same curvature as the rearwardly facing spherical surface, and a spherical center portion coupled to the cylindrical front end portion having the same curvature as the inwardly facing spherical surface. The plug member has a beam origin point coinciding with the diode's combined center of rotation and pivot point.

Abstract: The present invention concerns a measurement method of the alignment status of a shaft line (16) in rotating machineries and an apparatus for the implementation of the method. According to the invention, the displacement of alignment is measured at convenient points of the shaft line (16) from the displacement of an optically fanned laser beam (4) hitting sensor units (10, 11). At the beginning of a measurement session, a zero reference point is determined for the beam (4) and the measurement values of the sensor units (10, 11) are compared against this reference value during the measurement session. The relative displacement is obtained as the difference between the initial value and the value during the measurement. The apparatus and method is also applicable to the measurement of displacements in pipelines, long shafts and other similar systems.

Abstract: An apparatus and method are disclosed for characterizing the surface of mirrors in which a cross-grid type phase grating is illuminated from behind by light reflected from the mirror so as to create a grid-like interference pattern when observed along an observation axis. The fringe lines in the generated or observed interference pattern are correlated to the grating and observed for relative displacement from the grating axis. Apparent fringe index numbers for the fringe lines are used to determine coefficients for a plurality of monomial series which are in turn used to derive Zernike coefficients from which a wavefront contour is obtained. In order to reduce alignment errors during analysis, each fringe line is subtracted from the next lower order line and before monomial coefficients are determined.

Abstract: A collimator mounting assembly adapted for attachment to a missile launcher having a pivot member, called a traversing unit, at the apex of a tripod, that is adapted to replace a horizontally-oriented missile launching tube on the pivot member, and includes a mechanism for attaching the collimator mounting unit to the traversing unit, and adjustable tilt, azimuth, and elevation-controllable support plates for a tubular, horizontally-oriented collimator. This assembly permits the optical axis of the collimator placed atop the assembly to be parallel to the longitudinal axis of the missile launch tube, and permits referencing the collimator optical axis to the boresight of the missile launch tube.

Abstract: A shield tunnelling apparatus is provided that includes a first tubular shield body in which a cutter assembly for excavation and a drive mechanism for driving the cutter assembly are disposed; a second shield body connected to the rear of the first shield body so as to have a common axis therewith; a target disposed in the first shield body so as to receive a light ray directed along the axis; first optical path changing means disposed in the second shield body and capable of changing the optical path of the light ray directed toward the target such that the light ray travels along an optical path displaced away from the axis; and second optical path changing means disposed in the second shield body and capable of changing the optical path of the light ray passing through the first optical path changing means such that the light ray is again directed along the axis.