Abstract: A light beam is cyclically deflected by a rotating light deflector to scan an object such as an information storage medium. The scanning beam is detected by a light sensor located outside of the scanning region for synchronizing primary scanning. A plurality of n clock signals C.sub.1 through C.sub.n are successively generated by the delay element from an image scanning clock signal and a reference clock signal having the same frequency as that of the image scanning clock signal. One of the clock signals C.sub.1 through C.sub.n is selected as the image scanning clock signal dependent on the output signal from the light sensor. Dependent on the tap-to-tap delay error of the delay element: .+-..alpha.%, the maximum error of an image scanning position: 1/N pixel, and the period of the image scanning clock signal: T.sub.0, .DELTA.t.sub.0 which meets a prescribed condition is selected as a tap-to-tap delay time of the delay element.

Abstract: A document reader has a light source which is turned on upon energization, a read unit for reading an image of a document illuminated by the light source and a control circuit for controlling the energization of the light source. The read unit reads an intensity of a light reflected by a reference density pattern arranged externally of a document area prior to reading of the document and controls the energization of the light source in accordance with the detected light intensity.

Abstract: A variable threshold scan detector for use in raster output scan (ROS) systems, whereby the input scanning beam intensity is continually monitored and the threshold is set at a percentage of the signal value. Feedback from a peak detector circuit adjusts the threshold voltage to approximately 55 percent of the peak voltage. When the signal voltage exceeds the threshold voltage, the crossover circuit is enabled and a scan pulse is generated when crossover is detected. The scan detector ignores noise signals below the threshold voltage.

Abstract: An optical linear encoder for converting scanning light beams incident thereupon into a series of pulsatory light comprising light transmission parts for passing through the scanning light beams and light non-transmission parts for blocking transmission of the scanning light beams. The light non-transmission parts are alternately arranged with said light transmission parts in predetermined intervals that are determined by the amount of distortion inherently occurring in an optical system through which the scanning light beams travel.

Abstract: A spatial pixel clock synchronization system with jitter correction for an optical scanning system having a continuously running pixel clock source, start of scan and end of scan split photodetectors, circuitry for producing signals proportional to the respective light exposures of the halves of said photodetectors, and circuitry, including a switched filter circuit with two storage elements for each facet of the polygon of the system, for generating from said exposure signals a frequency correction signal for the pixel clock source.

Abstract: The device includes at least two diode arrays which contain some diodes which are defective. The defective diodes are compensated in that the respective diodes of the two arrays are aligned in pairs along the scanning direction, with each of the pairs containing at least one good diode. The device also comprises a programmed memory for controlling two switches and for accomplishing a winding or serpentine readout of the arrays. The device is well adapted for landscape scanning.

Abstract: Apparatus (10) for controlling a beam (12) of coherent light includes a reference scale (38, 138) provided with indicia forming a plurality of spokes having two sets of properties. The first of the two sets of properties is an evenly spaced first set of edges (41) arranged for generating a data clock exactly referenced to a position of a first of the two separate, perpendicular directions. A second set of edges (44) are each spaced variably from an associated one of the first set of edges (41) as a function of the other of the two separate, perpendicular directions, making the second of the two sets of properties a variable width of each of the spokes.

Abstract: A robotic vehicle is guided along a predetermined path which is to be traversed autonomously by the vehicle. As the vehicle is guided along the path, the area before the vehicle is scanned and discontinuities in the scan scene are reduced to a series of time separated pulses. The pulse series at selected locations along the path are stored such that the vehicle can autonomously retrace the predetermined path by matching pulse series generated by current scanning with stored pulse series. A scanner mirror receives and directs a laser beam through an area before the vehicle along the path to be traversed and receives reflected return signals from the scanned area. Optical detection means receive the return signals from the scanner mirror and generate raw scene signals which are doubly differentiated to generate pulse series representative of the discontinuities of the scanned area.

Abstract: An optical image reader is disclosed which effects the reading of an image on a given manuscript by moving a reading head provided with a plurality of photosensors over the surface of the manuscript and enabling the photosensors to directly discern the image information on the manuscript. In the optical image reader, the photosensors in the reading head are sequentially deviated in a direction perpendicular to the direction of the movement of the reading head and, therefore, are able to read the image information on the read points on the manuscript face to correspondingly deviated time intervals. Thus, the optical image reader operated at a high speed without any interruption.

Abstract: A light beam scanning apparatus includes a sweeping unit for sweeping a light beam in response to a first signal. A photodetector has a plurality of optical gratings arranged in an array in a predetermined direction in which the light beam is swept. The photodetector generates a second signal in response to a movement of the light beam along the grating array. A control circuit generates the first signal in response to the second signal. The control circuit detects a scan speed of the light beam based on the second signal, and adjusts the first signal in response to the detected scan speed to control the scan speed of the light beam such that the detected scan speed substantially coincides with a predetermined speed.

Abstract: A scanning apparatus with large resolution capacity utilizes a laser means as a light source (1), the light beam (L1) of which is deflected such as to substantially follow the optical axis of an f-.theta. lens (5) after having passed a diverging lens (2). A rotating polygon mirror or spinner (4) is disposed on the opposite side of the f-.theta. lens (5), such that a reflected sweeping beam is obtained. This sweeping beam is allowed to pass once again through the f-.theta. lens (5) and is divided in beam dividers (7,10) for generating a sweeping scanning beam (L3) and a reference beam (L5). The dots (P, Q) formed by the scanning and reference beams (L3, L5) sweep muturally simultaneous, the dot (Q) of the reference beam being utilized to define, with the aid of a clock pulse scale (11), the exact position of the scanning beam dot (P) on a scanned object (K).

Abstract: When producing images of the earth using rotating planar mirrors mounted in an aircraft, errors are introduced by roll, pitch and yaw of the aircraft. These errors are overcome in one of two ways. In the first way, the scanning planar mirror (30) is mounted on a shaft (54), the axis of which can be moved through small angles during the rotation of the shaft. This movement of the shaft is achieved by supporting the shaft (54) so that the end which does not carry the mirror is located within a cylindrical hollow region (60) at the end of an outer shaft (50). The two shafts rotate together. A pair of permanent magnets (51,52), each mounted axially in a respective shaft, have opposite poles adjacent to each other. The attraction of the magnets is perturbed by a transverse magnetic field established by an electromagnet (57,58,59) mounted outside the outer shaft (50). The current in the winding of the electromagnet depends upon the value of signals which are proportional to pitch and yaw of the aircraft.

Abstract: A circuit for correcting the data rate to compensate for polygon facet irregularities in a flying spot scanner is described. A crystal controlled oscillator is used to generate the system clock. As each facet becomes the current facet, a number of pulses appropriate for that facet are subtracted from the bit clock stream so that there will always be a constant ratio between data speed and scan speed regardless of the scan speed variations between individual facets.

Abstract: A photodetector arrangement has an elongate, transparent light conducting member for causing light incident on a side periphery thereof to propagate axially therethrough toward an end thereof. A photosensitive device is located in the vicinity of the end of the light conducting member to produce an electric signal in response to light streamed through the end of the light conductor. A light interceptor is provided for limiting a quantity of light which is incident on a part of the light conductor adjacent to the photosensitive device to be detected by the device. Alternative to the light interceptor, the photosensitive device may include a solid state image sensor having an array of photosensitive cells disposed to receive light streamed out of a portion of the end of the light conducting member, which portion is near to the side periphery of the light conducting member on which the light is incident.

Abstract: The system includes a primary scanner which produces a scanning optical beam, and a photoresponsive error sensor which measures over the scan path the successive differences between the actual position of the scanning beam and the desired position of the scanning beam and produces error signals. The secondary scanner is connected to the error sensor for response to the error signals to dynamically correct the position of the scanning beam during the course of the scan. The primary scanner provides a main optical scanning beam and an auxiliary optical scanning beam traversing substantially the same optical path. The error sensor includes a graticule mask having a substantially uniform optical density along the desired scan path and a graded optical density transverse to the desired scan path of the auxiliary scanning beam.

Abstract: In a light beam scanning device, first and second light spots scan a scanning plane and a planar grating pattern, respectively. The grating pattern has alternating transparent and opaque parts extending parallel to one another and is rotated by a predetermined angle in its own plane. A speed of scanning the grating pattern by the second light spot is detected to correct irregularities in a speed of scanning the scanning plane with the first light spot. Further, the scanning length on the scanning plane can be finely adjusted by the rotation of the grating pattern.

Abstract: The image formed by a laser flying spot scanner on a photosensitive medium is subject to error in size and/or position because of deviation of the photosensitive surface from a nominal position. The deviation will occur if the substrate carrying the photosensitive surface does not have a uniform thickness. In a scanning system having a code mask that produces reference signals for controlling timing of writing beam modulation, compensation for the error is provided by maintaining a fixed distance between the code mask and the surface of the medium. The code mask floats freely upon the medium surface to move up and down with height variations of the surface as the medium passes under the code member and under the writing beam. Alternatively, the platen that supports the photosensitive medium is allowed to float and is continuously urged upwardly against spacing or position sensing devices to maintain the medium surface at a fixed distance from the mask.

Abstract: A light beam scanning reticle having a grid pattern with transparent portions and opaque portions alternately arranged in a light beam deflection direction and having a variable period in a direction perpendicular to the deflection direction. The grid pattern is movable in the deflection direction, and irregularity in the speed of scanning a light spot on a scanning plane is corrected with a photo-electric signal which is provided through the grid pattern.

Abstract: A pattern scanner comprises a plurality of light-sensitive elements guided in X and Y co-ordinate directions to scan a screen on which one or more pattern pieces are laid. The scanner detects outer and inner boundaries of the pieces, and analyses the inner boundaries to identify information such as grain direction, piece identity and drill holes.

Abstract: A robotic vehicle is guided along a predetermined path which is to be traversed autonomously by the vehicle. As the vehicle is guided along the path, the area before the vehicle is scanned and discontinuities in the scan scene are reduced to a series of time separated pulses. The pulse series at selected locations along the path are stored such that the vehicle can autonomously retrace the predetermined path by matching pulse series generated by current scanning with stored pulse series. A scanner mirror receives and directs a laser beam through an area before the vehicle along the path to be traversed and receives reflected return signals from the scanned area. Optical detection means receive the return signals from the scanner mirror and generate raw scene signals which are doubly differentiated to generate pulse series representative of the discontinuities of the scanned area.

Abstract: The method and apparatus for scanning for radiated energy employs a scanning mirror (1) pivoting azimuthally about a vertical scanning axis (2) and capable of being pivoted also about a pivotal axis (3) that makes an angle with the scanning axis. The mirror reflects the incident IR energy onto a vertically disposed field composed on n individual IR detector elements (22) having (n-1) spacings of equal magnitude. The horizontal motion of the mirror takes place in customary manner but the pivotal motion is smaller than the individual detector elements and their separations. Therefore, the same thermal image requires several pivotal processes and, hence, also several mutually parallel horizontal scanning motions, resulting in achieving greater resolution of the image.

Abstract: A picture scanning and recording system in which a scanning for "sharp" signals and a scanning for "unsharp" signals are alternately conducted, each in half periods of scanning, by means of a common photoelectric converter. One of these two series of signals is temporarily stored in a memory for synchronous processing with the other series of signals that is just being produced in such a manner that no inconformity is brought about into recording signals of detail contrast.

Abstract: Disclosed is a method and an apparatus for detecting the leading edge of a sheet which is on the way to the scanning-and-reading station of an image read-out system. Detection is performed by exposing, just ahead of the scanning-and-reading station, the traveling sheet to the same scanning beam of light as used at the scanning-and-reading station, and by detecting the sudden change in the amount of reflection on arrival of the sheet at the station due to the difference between the reflection coefficients of the sheet and the underlying conveyer belt. Preferably, the scanning for detecting the leading edge of the sheet is at a higher frequency and smaller amplitude than the scanning for reading an image on the sheet.

Abstract: A method and apparatus for producing a time advanced pulse train from an input pulse train using a phase locked loop with time delayed feedback. The apparatus is used to generate clock signals that occur at a precise relationship to the position of a scanning or writing laser beam.

Abstract: A laser beam scanner with encoder and a laser beam plotter with encoder are disclosed. The scanner provides for unsharp masking by alternating between a large scan beam and a small scan beam on alternate scans. Compensation for non-straight scan lines is achieved through a small linear galvonometer placed in the scanning optics. An equal conjugate optical system is utilized to allow encoder information to be obtained from a stationary image of the main scanning and plotting galvonometer mirror.

Abstract: An apparatus for reading an original surface by illuminating it with a slit-like light beam includes a fixed linear light source, a cylindrical parabolic mirror fixedly provided so that the focal line position thereof is coincident with the linear light source, the light beam from the linear light source being directed in a predetermined direction by the parabolic mirror, a cylindrical scanning mirror disposed so that the generating line direction thereof is coincident with the generating line direction of the cylindrical parabolic mirror, the cylindrical scanning mirror condensing the light beam from the cylindrical parabolic mirror in a slit-like form on the original surface and being moved along the original surface to thereby illuminate the entire area of the original surface, and an optical system movable with the cylindrical scanning mirror to read the light beam scattered by the original surface, the optical system includes a line sensor array and optical means for directing the scattered light to the

Abstract: A flying spot scanner is used to expose a photosensitive surface to an intensity modulated beam of light to build up an image on the photosensitive surface.

Abstract: An electro-optical scanner which can write and read with common optics by using a phase hologram near the focal plane of the scanned surface.

Abstract: An incremental optical position sensing system utilizes a single laser beam and an out of focus grating which is between a pair of lenses whose focal planes coincide. The scanning laser beam passes through the first lens, scans the grating, passes through the second lens and impinges upon a pair of sensors. The phase correlation between the signals from the sensors is used to determine the direction of motion of the laser beam and an up/down counter is utilized to accumulate the absolute position of the beam.

Abstract: Electro-optical apparatus, system and method for measuring distance to a relatively moving surface, such as distance to a road surface from a vehicle frame of reference passing thereover. The apparatus includes a light transmitter for projecting a rectangular beam vertically downwardly onto the road surface. A rotating scanner includes a circumferential array of facets for sequentially receiving the image diffusely reflected from the road surface and reflecting such image through a rectangular reticle onto a photodetector. Reference beams are sequentially reflected by the road image-reflecting scanner facets onto a reference detector. Distance to the road surface is then determined as a function of the angle of incidence of the road image onto the scanner by comparing the time of incidence of the road image to the times of occurrence of the reference reflections on the reference detector.

Abstract: A circuit is shown for use within an optical scanning system utilizing at least two scanning beams for scanning a grating and a document. A high frequency reference signal is applied to a counter which also receives the grating signal. The grating signal is delayed by a counter to assure that the grating signal has been synchronized with the reference signal. As the scan across the document hits a reference target, a picture element signal is generated which is also applied to the counter. The counter is enabled upon receipt of a positive going signal from both the reference signal and the picture element reference signal. As the reference signal is a much higher frequency than the picture element signal, any error in misalignment between the grating whose signal is synchronized with the reference signal and the target is eliminated by the high frequency reference signal. A further delay counter within the circuit eliminates errors caused by the width of the target signal.

Abstract: An optical sensing system that detects the angular orientation of weft threads in a moving web of a textile has a sensor array that receives light transmitted through the web from a light source. The sensor array is preferably a single monolithic chip that includes a radial pattern of photosensitive areas that each generate an electrical signal proportional to the total intensity of the light incident on the area. The areas are elongated and narrow so the moving shadow of a weft thread passing over the area will modulate the output signal. The modulation is strongest when the thread is generally aligned with the area. Electronic circuitry generates a DC signal associated with each area that is proportional both to the magnitude and frequency of the modulation of the signal. The circuitry also compares these signals, selects the largest one, and generates an analog output voltage characteristic of the area associated with the largest signal.

Abstract: A galvanometric tilting-mirror scanning system shifts an image of an original projected onto a photodiode row in a direction transverse to such row. The tilting-mirror mechanism is provided with an oil-filled damping chamber, heated and maintained at stabilized temperature. The control voltage driving the tilting-mirror system includes a sawtooth component whose lower-slope flanks determine the mirror's scanning sweep; a negative pulse which effects mirror tiltback or flyback; a positive pulse which brakes the tiltback and accelerates the mirror back up to its forwards-direction scanning-sweep speed; and finally a corrective component. The corrective component has the form of a pulse which increases the slope of the sawtooth component's lower-slope flanks during a time interval extending beyond the system's vertical blanking allotment, to compensate the non-linearity in the motion of the mirror which would exist during its forwards-direction scanning-sweep interval in the absence of the corrective component.

Abstract: A constant magnification optical tracking system for continuously tracking a moving object. More particularly, a constant magnification optical tracking system is disclosed wherein a traveling objective lens (14) maintains a fixed relationship to an object (10) to be optically tracked. The objective lens (14) is chosen to provide a collimated light beam (32) oriented in the direction of travel of the moving object (10) A reflective surface (18) is attached to the traveling objective lens (14) for reflecting an image of the moving object (10) to the lens. The moving object (10) is maintained at the focal point of the traveling objective lens (14). In an exemplary embodiment, the object to be tracked is a free-falling object, and the traveling objective lens is mounted on a holding structure (16) slidably attached to a vertically-extending guiding member (38) so that the free-falling object (10) will be located at the focal point of the objective lens for at least a portion of its free-fall path.

Abstract: A two-dimensional scanning device provided with a first deflector for deflecting a collimated beam, a second deflector for deflecting the incident beam in a direction orthogonal to the deflection direction of the first deflector, a scanning lens disposed between the first deflector and the second deflector, a scanning surface for imaging the scanning beam from said scanning lens through the second deflector, and a device for moving the scanning lens in the direction of its optic axis in synchronism with the rotation of the second deflector to thereby obtain a strain-free two dimensional scanning figure on the scanning surface.

Abstract: A system for viewing a zone to detect the presence of an article carried therein on a conveyor. In one embodiment, the system includes a laser source which projects a line-beam of coherent light toward the zone, which beam is intersected, along a length thereof, by the planar field of view of a reflection detector whose view-plane contains the beam. In another embodiment, the system uses a laser source which projects a planar beam of coherent light which is intersected by the field of view of a reflection detector whose view-field has both length and breadth dimensions where it intersects the laser beam. In both embodiments, the region of intersection of the laser beam and the detector's field of view is spaced from the conveyor.

Abstract: An aerial vehicle rotating in gyroscopic fashion about one of its axes having an optical system operative to scan an area below the vehicle in determined relation to vehicle rotation. A sensing device is provided to sense the physical condition of the area of scan and optical means are associated therewith to direct the physical intelligence received from the scan area to the sensing means. Means are provided to incrementally move the optical means through a series of steps to effect sequential line scan of the area being viewed keyed to the rotational rate of the vehicle.

Abstract: This invention relates to a scanning apparatus in which a spot of light is swept or scanned over a receiving surface (11,27). The intensity of the spot may be modulated during scanning to build up a two-dimensional image on the receiving surface, or alternatively, the spot of light may be used to analyze the receiving surface to monitor its reflectivity or transmissivity.

Abstract: In accordance with a presently preferred embodiment of the invention, a servo control loop is disclosed using optical feedback to control the movement of a small, lightweight scanning mirror. The optical feedback is accomplished by reflecting radiation from the scanning mirror and imaging such radiation onto a pair of radiation detectors. An optical element having alternate relatively transparent and opaque regions is disposed in the optical path between the scanning mirror and the detectors to modulate in phase quadrature the intensity of radiation beams received by the detectors. The output signals from the detectors are used to develop a feedback signal to close the servo loop.

Abstract: Disclosed is a scanning apparatus used in, for example, a facsimile copying device. A scanning mechanism carries out a time sequential scanning of a manuscript sheet by, for example, a laser. A photoelectric element holding block, having a slit for allowing the passage of scanning beams from the scanning mechanism, travels jointly with the time sequence scanning of the manuscript sheet. A plurality of photoelectric elements are set around the slit of the holding block.

Abstract: An optical scanning device for scanning a document to produce image signals related to the density of the image on successively scanned document areas includes a platen for supporting a document and a surface of substantially uniform reflectivity extending along the edge of the platen. A bar of light is directed such that it strikes the document and the surface of substantially uniform reflectivity and moves across the document in synchronization with optical scanning of the document. Light reflected from the surface of substantially uniform reflectivity is directed to a plurality of reference transducers which sense the position of the bar of light. A servo control loop, responsive to the reference transducers, positions a reflector during the scanning operation such that the area on the document being scanned is properly illuminated.

Abstract: A projecting optical system having a first lens system, on one focal plane of which a first plane is disposed, a light beam deflector disposed on the opposite side of the first plane relative to the first lens system and to deflect light beams in a predetermined direction, and a second lens system which receives light beams from the light beam deflector and collects the same on a second plane disposed on its focal plane, wherein the first and second lens systems have one and the same distortional characteristic, the distortion to be generated in the first lens system is compensated by the distortion to be generated in the second image-forming lens system, irrespective of the deflecting action of the deflector, to thereby sequentially project the image on the first plane onto a predetermined position on the second plane.

Abstract: A scanning optical system for incrementally generating a composite image of a strip-scanned object. A light beam is swept by a first rotating mirror across the object to scan-illuminate same. Imaging light from the object is then projected to an intermediate image station across which it is swept by a second rotating mirror. A stationary aperture at the intermediate image station transmits or reflects, at any instant, only a desired incremental image of the scanned object. This desired incremental image is in turn relayed to a final image plane by reflection from a third rotating mirror so as to synchronously lay down on the image plane a composite of the instantaneous increments.

Abstract: An optical scanner for scanning an image on a document to produce an electrical signal representing the image density of the image at successively scanned points positioned along a scan line on the document includes a platen for supporting the document in a scan plane. A rotatable mirror in the scanner optical system is rotated at a non-uniform angular velocity to scan the document at a controlled scan rate which may be selected as a uniform scan rate. Rotation of the mirror is controlled by means of a servo control loop responsive to a reference signal and to the output of a reference transducer which receives light from a reference grating as the mirror is rotated.

Abstract: A light beam scanning apparatus for scanning with a light beam from a light beam generating unit such as a laser is provided with at least a light beam detector on a scanning line of the light beam to detect the arrival of the light beam maintained in scanning motion by a scanner. The output of the detector energizes a first control to control the scanner thereby maintaining the maximum angle of rotation thereof at an approximately constant value. A beam detect signal released from the first control is utilized for determining the start position of information recording.

Abstract: Optical scanner with a light beam reciprocated parallel to itself includes a stationary inlet for the light beam, an elongated first prism having a parallelogram shape disposed downstream from the stationary inlet in travel direction of the light beam, the first prism extending transversely to the light beam and having an inlet end through which the light beam is admitted to the first prism and twice reflected therein, the first prism having an outlet end from which the light beam leaves the first prism in a direction parallel to the direction in which it is admitted through the inlet end to the first prism, a second prism similar to the first prism having an inlet end disposed downstream of the outlet end of the first prism in travel direction of the light beam, the second prism having an outlet end determining respective location for the light beam leaving the scanner during a scanning operation, a first rotating carrier for the first prism having a mathematical rotary axis extending in the same direction a

Abstract: Apparatus for use in an optical scanner for accurately controlling, from scan to scan, the position in which the horizontal scan line is formed. A closed electrooptical feedback loop is employed to sense, prior to the formation of each horizontal scan line, the vertical position of the scanning light beam in the plane of the recording element and, in the event its position is displaced from a nominal position, to produce an error signal to move the beam to the nominal position.

Abstract: A reproduction scanning system having intermediate storage between input and output scanning stations wherein an input document is scanned in first and second directions, the first direction being orthogonal to said second direction, and the electrical signals representative of information on said scanned document being stored on an intermediate storage member for storage, signal processing or data manipulation. The information stored in the storage member may be read out and reproduced on a reproducing medium. Other system features include input scan reversal for alternate bound pages during bound volume scanning, synchronization of the system by a clock associated with the storage member, input/output interleaving with a print interrupt feature, image centering and edge fadeout for image reduction, and independent magnification demagnification by separately variable raster spacing.

Abstract: An electro-optical system for the repetitive repositioning of a cyclically moving beam of radiation to a preselected point in space, particularly as applied to electro-optical web inspection.

Abstract: A line scanning apparatus employing a multiplicity of linear arrays, the linear extent of which is less than the length of the scan line. To permit an entire line to be covered, the arrays are offset from one another in the direction of scan with adjoining array ends overlapped. To correct for the misalignment and redundancy introduced, the image data from the arrays is buffered until a line is completed when readout is initiated. During readout, cross over from one array to the next is effected within the overlapped areas and the redundant data discarded.