Abstract: Methods are provided to image patterns on a media. A pitch of a repeating pattern of sub-regions is determined and an imaging head is operated which has an array of individually addressable channels to direct imaging beams to form an image swath on the media. The individually addressable channels are controlled to image the repeating pattern of features and the pitch of the repeating pattern of features is adjusted to equal substantially the pitch of the repeating patterns of sub-regions.

Abstract: The present invention relates to a laser processing apparatus and the like having a structure for implementing at the same time both an efficient laser processing in the place where a laser beam is difficult to reach and a laser processing without damages in the place where the laser beam is easy to reach. This laser processing apparatus comprises a laser light source, an irradiation optical system applying a laser beam to an object while scanning the laser beam, a photo-detector detecting the laser beam applied from the irradiation optical system, and a control section of making switching between a continuous oscillation and a pulse oscillation of the laser beam at the laser light source.

Abstract: Methods and systems are described for a system for measuring aberrations in a wave front. In the improved system multiple closely-spaced, small-aperture laser beams traverse an aberrating flow that introduces deflections of small-aperture laser beams from which aberrated wavefronts can be constructed. These beams may then be focused on position sensing devices using focusing lenses. The position sensing devices may then detect the positions of these beams and a difference between the detected position and the unaberrated position of the beams detected. This information may then be used to determine information regarding the optical aberrations introduced by the flow that may be used, for example, in improving communications systems and/or laser weapon systems.

Abstract: A method and a measuring instrument for determining the position of an edge to be measured on a pattern on a substrate are described. A complete, nonlinear model intensity profile, which identifies the edge to be measured, of a model edge is ascertained and stored, and a desired edge position xk is defined therein with subpixel accuracy. A camera image of the substrate having the edge to be measured is acquired, and a one-dimensional measured intensity profile of the edge to be measured is determined therefrom. The model intensity profile is identified in the measured intensity profile with an indication of its location xm relative to a reference point. The desired position p of the edge to be measured is determined with subpixel accuracy as p=xm+xk.

Abstract: A method and apparatus is disclosed to precisely locate an edge of an imageable plate mounted on a drum or other support surface. A light source and light sensor are used to measure the difference in reflectivity between the plate and the support surface. The drum or support surface contains at least one groove to increase the difference in reflectivity between the plate and the support surface. The groove may also contain an anti-reflecting layer to further increase the difference in reflectivity. The groove may also have a geometric shape that causes incident light to be directed away from the light sensor.

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 movements of the target, and the spherical coordinates of the target relative to the tracking unit are then obtained. The target can be, for example, an active device incorporated into a moveable device such as a remote controlled robot.

Abstract: A method and a system for monitoring combustion condition are provided for monitoring the state of combustion in a garbage incinerator, an internal combustion engine, or the like. Combustion off-gas produced by combustion is collected and ionized to produce ions which are fed to a mass spectrometer for detecting a signal strength associated with an ion for each mass-to-charge ratio. The degree of unsaturation is calculated for an ion detected by the mass spectrometer from the mass-to-charge ratio of the ion. Then, signal strength values associated with ions having the same degree of unsaturation are accumulated for each degree of unsaturation. The monitoring system can keep track of components in combustion off-gas classified into respective compound groups in real time to monitor an exact combustion condition.

Abstract: Methods and apparatus for calculating alignment of layers during semiconductor processing are described. In one embodiment, first and second alignment targets are formed over a substrate and include respective pairs of first and second alignment target edges. The second alignment target defines a point of reference. First and second distances are measured between the first alignment target edges and the second alignment target edges as respective first and second functions of the distance from the point of reference. The first and second functions are differenced to define a linear equation having a slope and ii an intercept which contains offset components in two different directions. In a preferred embodiment, third and fourth alignment targets are formed over the substrate, with the fourth alignment target defining a different point of reference.

Abstract: The invention relates to a key decode apparatus for helping to automatically extracting and measurement depths and spacings of cuts an object key and decodes when duplicating an original key. A key holder is provided forming shadow image of a key side view by positioning the original key vertically along its longitudinal axis with the key's flat sides in vertical plane, position an object key between video camera and luminescent light strip. The video camera gets the shadow image of the key side view and sends it to a computer that stores the shadow image in memory that may measure depths and spacings of key cuts and compares with known original key manufacturers information in memory, decodes and sends it to be displayed and can be used in cutting machine for duplicating the key.

Abstract: A system for controlling steering of a vehicle, including a steering means such as a steering wheel with an electric motor which assists steering of the driven wheels of the vehicle, first steering control means for controlling the motor, a CCD camera for detecting a lane condition of a road on which the vehicle travels, a yaw rate sensor for detecting motion of the vehicle, steering assist torque calculating means for calculating a steering assist torque necessary for holding the lane, a torque sensor for detecting an actual steering torque manually applied to the steering means by the driver, and second steering control means for calculating a torque command to be output to the first steering control means based on the steering assist torque calculated by the steering assist torque calculating means and the actual steering torque such that the torque command decreases.

Abstract: The invention is a multifunctional, mobile appliance capable of performing a variety of tasks safely, quietly, without pollution, and out of sight of its owner. Such tasks might include lawn mowing, fertilizing, and edging, floor vacuuming, waxing, and polishing, or rug shampooing. In its preferred implementation, the mobile unit 1 would obtain precise real time and position information using the Real Time Kinematic Global Positioning System. The user initially guides the appliance around the work-area perimeters. The device then uses this information to determine the full working area. Proximity detectors and impact sensors help the appliance avoid unexpected obstacles. The device is quiet enough to perform its task in the middle of the night while its owner is asleep, but can be programmed to work continuously or during any user-specified time interval. The small turning radius of the appliance allows it to follow intricate perimeters.

Abstract: A rotation-angle measurement for printing presses with at least one marking (2) arranged on a rotating element (1) and at least one sensor (3,4) which detects marking (2). The at least one marking (2) extends along the entire circumferential path (5) and is arranged on the element (1), the position of which is to be determined.

Abstract: The invention relates to an improved key making machine that automatically extracts characteristics of an object key without human intervention. The position and alignment of the object key is automatically determined, key characteristics extracted and compared with known key manufacturers' information stored in memory, an appropriate key blank is identified, cut and dispensed to the customer.

Abstract: An improved automated, self propelled lawn mower (14) utilizing a rotating directional loop antenna (36) that determines its position within the cutting area by measuring the angle between transmitters(20A, B, & C) placed in a known configuration beyond the cutting area, and by calculating the solution of simultaneous circle equations (96 & 98) defined by that configuration. Orientation is determined by comparing present and previous positions. Stored path information is compared with the calculated position to determine steering signals which direct the mower to move directly toward the next point in the desired path. When the mower reaches that point the next coordinates are retrieved from memory and the process is repeated similarly for all successive points in the path. The simplicity of programming the path makes this automated lawn mower very versatile and flexible.

Abstract: In a method and apparatus for duplicating an original key, the keyway and keycode of the original key are measured and duplicated in a preform. The preform used in the duplication process need not include any keyway or keycode prior to the duplication process and, therefore, a single type of preform may be used in generating duplicates of many different types of keys. The apparatus may be automated to take the measurements of the original key and to cut the duplicate key, thus reducing the possibility of producing a nonfunctional duplicate.

Abstract: A scanner which includes a motor for driving a load and circuitry for providing a position error signal responsive to the difference between a predicted position of the load and the actual position of the load, preferably a mirror scanning a scene. The motor is driven in response to the position error signal. The position error signal is provided plural times during a single scanning of the scene. The circuitry for providing a position error signal includes a closed loop filter system for filtering the error signal to provide a filtered error signal, an adaptive filter system for operating on the filtered error signal to provide an adaptively filtered error signal and summing circuitry for summing signals indicative of the predicted position, the filtered error signal and the adaptively filtered error signal. The closed loop filter system includes, in series, at least one first order lead lag filter and a double integral plus proportional filter.

Abstract: The invention provides an optical tracing system for measuring elevation of a reference body above a reference surface, comprising a laser transmitter radiating a light beam in a downward direction; an optical unit for imaging the radiation reflected from said body and said surface on a detector; filtering means for separating light originating from said laser from background illumination, and signal processing means for identifying said reference body and for measuring the elevation thereof from said surface.

Abstract: The invention relates to a key making machine that automatically extracts characteristics of an object key without human intervention. An object key is automatically aligned, key characteristics extracted and compared with known key manufacturers' information stored in memory, an appropriate key blank in a robotically accessible inventory is selected, cut, deburred, and automatically dispensed to the customer.

Abstract: An earth sensor for use in orbiting satellites over an altitude range between low earth orbit (LEO) and geosynchronous orbit (GEO) and beyond employs a combination of both visible wavelength senor technology and infrared (IR) sensor technology to result in high accuracy capability. During the vast majority of an orbit of the satellite, the sensor is operating in the visible region using reflected sunlight from the earth horizon. During the relatively small time period of the orbit when the sun is behind the earth and it is not possible to operate the sensor in the visible region, precise attitude information is generated by earth radiance balance operating in the IR region. The sensor therefore exhibits the known advantages and accuracy of operation in the visible region for a major portion of an orbit of a satellite, but also maintains attitude control of the satellite during a relatively small portion of the orbit when operation in the visible region is not possible.

Abstract: A FIG. 1 is taken by a camera having optical/electrical elements arrayed in matrix, signals of pixels of the picture taken by the camera 2 are converted into binary data in a binary circuit 11, and the binary data is temporarily stored in a binary data storage device 12. The reference point 0 is determined on the edge of the figure, and radius L of the circuit scanning line 21 is determined based on the shape of the figure, and reference point 0 and the radius L of the circle scanning line 21 are inputted through an input unit 13. Coordinate data of pixels on the circuit scanning line 21 is operated based on the inputted numeric values in an arithmetic circuit 15. Binary data on pixels corresponding to coordinate data are read in the detector 16. When the pixel corresponding to the edge of the FIG. 1 is detected, a vector directed from the reference point 0 to the pixel is decided, and first and second drives 7, 8 are driven according to the vector.

Abstract: A FIG. 1 is taken by a camera having optical/electrical elements arrayed in matrix, signals of pixels of the picture taken by the camera 2 are converted into binary data in a binary circuit 11, and the binary data is temporarily stored in a binary data storage device 12. The reference point 0 is determined on the edge of the figure, and plural coaxial circle scanning lines A, B about the reference point 0 which differs from each other in radius are set. In arithmetic circuit 15, coordinate data of pixels on the circle scanning lines A, B is operated. In the detector 16, binary data of the pixels on the circle scanning lines A, B is detected. In the decision circuit 17, the vectors from the reference point 0 to the detected pixels on the circle scanning lines A, N, and the vector angle between the obtained vectors is operated. A speed signal according to the vector angle is generated for driving the first and second drive 7, 8.

Abstract: A mobile body such as an automobile is controlled to move substantially along a target path by a control system. The control system determines a target point on the target path, a control quantity such as a yaw rate to reach the target point to cause the mobile body to reach the target point from an optional position, the direction in which the mobile body moves at the target point based on the control quantity to reach the target point, the angular difference between the direction and the target path at the target point as a target point angular difference, and a target control quantity such as a target yaw rate for the mobile body by correcting the control quantity to reach the target point based on the target point angular difference. The mobile body is controlled based on the target control quantity.

Abstract: An image sensor comprised of an array of photo-sensing devices is devised to generate digital images of objects. Each photo-sensing device consists of four identically shaped photo-sensitive surfaces, each photo-sensing surface being shaped into an isosceles trapezoid having 45.degree. base angles. One photo-sensing device corresponds to one pixel of the digital image. Pixels that representing image edges can be directly located and orientations of image edges represented by those pixels can both be determined by arithmetically processing the values of electrical signals generated by the photo-detecting devices.

Abstract: The apparatus comprises a horizontal conveyor (1), on which the glass panes (4) are conveyed while they are supported by backing means (2), which by their supporting forward surface define a plane of pane travel (3), a tool (18) for processing the glass panes (4) along their edge and a drive motor for displaying the tool (18) in a direction which is parallel to the plane of pane travel (3) and transverse to the direction of travel (5). For a control of the movement of the tool (18), electronic line cameras (8) are provided, which are so directed toward the plane of pane travel (3) that their scanning lines extend in or parallel to the plane of pane travel and at right angles to the direction of travel (5). For measuring the distance traveled, a displacement pick-up (15) is provided, which is synchronized with the horizontal conveyor (1). The signals from the line cameras (8) and from the displacement pickup (15) are delivered to an evaluating computer (16) for controlling the tool (18).

Abstract: A method of monitoring and controlling the quality of pen markings on a plotting medium by qualifying each pen based on optically sensing across a sample line drawn on an actual medium. During each subsequent plotting task of a particular pen which has been qualified, an actual line plot is optically sensed across a selected point to make a comparison with the sample line. If the actual line plot is unsatisfactory, the deficient pen is replaced and the plot is restarted from the beginning, or retraced from the last good verification, or is stopped to allow the user to select an appropriate corrective procedure.

Abstract: The invention relates to a warning device in a motor vehicle for detection of unintentional change of course. The invention utilizes existing white road lines being scanned by two detectors (A) mounted far out in the front on the left-hand and the right-hand side of the bumper of the vehicle. IR transmitting diodes (1) located in the detectors are fed from a transmitting unit of an electronic unit mounted in the vehicle with a pulsed signal voltage. The light emitted from the IR diode (1) is reflected by the lines (10) of the roadway (11) to an IR receiving diode (12) mounted in the detector (A), this diode not being affected by visible natural and/or artifical light but is only activated by the pulsed, reflected IR light. The signal voltage received by the IR receiving diode (12) is connected to two receiving parts mounted in the electronic unit, one for the right-hand and one for the left-hand side of the vehicle compartment, for conversion into an acoustic or an optical warning signal to the driver.

Abstract: An optical probe head has a front optic and an annular enclosure surrounding the front optic. The enclosure contains the illuminating device of the probe head. The front optic is rigidly attached to the optical probe head and the enclosure having the illuminating device and surrounding the front optic is attached to the optical probe head so as to be radially yieldable. In the case of a collision, only the enclosure having the illuminating optics is therefore deflected; whereas, the imaging optics remains undisturbed. In this way, a follow-up calibration of the probe head after a collision is no longer required.

Abstract: Apparatus for scanning tracks in an information plane of a record carrier by means of three beams. The radiation from each one of the three beam spots is push-pull detected by one of three split detection systems (10, 11, 12). A position signal Ep which is a measure of the position of an adjustable element (9) in the apparatus, which element determines the transverse positions of the spots with respect to the track being scanned, is derived from the detector signals. In response to the position signal a control circuit 33 corrects the position of the element (9). A normalizing signal, by which the position signal Ep can be made independent of the intensity of the beams, can also be derived from the detector signals.

Abstract: An optical sensor for monitoring plotter pen performance by sensing the quality of lines drawn on a medium. An LED emitting green light beam is angularly directed toward an underlying line so as to reflect into an optical sensor which measures the print contrast ratio of a point on the line. Circuit means amplifies and filters the signal generated by the optical sensor.

Abstract: An optical scanning device for scanning an information plane (2) having tracks is described, which device comprises a radiation source (4) supplying a scanning beam (3) and an objective system (5) for focusing the scanning beam to a scanning spot on the information plane (2). To obtain two tracking spots, two grating parts located at both sides of the scanning beam and capturing border rays from the radiation source are used.

Abstract: There is disclosed a method for the adjustment of an optical row of sensors which, for guiding a driverless vehicle along an optical guideway, is secured at the vehicle transversly with respect to the vehicle travel direction. Known systems attempt to accomplish a compensation of component tolerances by carrying out an adjustment between the measurement signals of the sensors. However, this leads to inaccurate measurement values. A post-adjustment of a contrast value is not contemplated with these systems. The invention eliminates these inaccuracies and affords an exact post-adjustment. On the one hand, this is attained in that the sensors are adjusted by a calibration surface and the adjustment values for controlling the sensors are stored in an adjustment table. On the other hand, it is proposed to perform the adjustment operation at the site of use of the equipment and to provide an adaptive post-adjustment of the thus set adjustment table.

Abstract: A coordinate measuring machine (10) having laser interferometers (80, 176, 196) arranged to measure "X" and "Y" carriage (52, 16) and probe shaft (56) motions, in which fiber optic cables (66, 72) are used to deliver a laser beam from a laser beam generator (60) to at least some of the interferometers (17). A special clamp (76) and adjustment flexure (74) is used to mount and align the fiber optics (66, 72) to beam splitters (64) dividing the laser beam from the laser generator (60) for use along each axis. The adjusting flexure (74) comprises a series of plate sections (120, 122, 124) interconnected with a pair of webs (142, 164) allowing tilting about two orthogonal axes with a pair of adjusting screws (148). A pair of locking straps (154) secure the plates (120, 122, 124) in the adjusted position. A double clamp (76) having axially spaced clamping jaws (102, 104) is connected to the flexure (74) and provides a stable securement of the optical coupling (96) to the flexure (74).

Abstract: A optical profile reader, particularly for key duplicating machines, incorporationg a photoemitter (16) positioned on one side of the profile (11) to be read, and a photodetector (21) facing the photoemitter (16), but on the opposite side of the profile to be read. Stepper motors (5, 8) are included for causing the profile (11) to be read to move orthogonal to the direction of a light beam striking the profile to be read. An electronic circuit controlled by the output signal of the photodetector (21) is also provided. The electronic circuit uses a threshold discriminator (25) set at a value between the values corresponding to the maximum and minimum illumination states of the photodector (21). The threshold discrimination circuit (25) also controls the operation of the stepper motors (5, 8).

Abstract: A monitoring device is provided for at least one current pickup of a conveyor truck in a conveyor system running on tracks, whereby when viewed in a direction of travel the current pickup has a profile configuration which changes through wear as the pickup traverses a live rail. The device comprises a receiver for a test signal fixedly mounted on one side of the live rail, a transmitter mounted on the other side of the live rail, a test signal evaluating device that responds to a modified profile configuration of the current pickup resulting from wear, and an alarm signal triggered at a predetermined level of wear of the current pickup.

Abstract: There are provided a method of and an apparatus for guiding a self-steering or driverless vehicle along an optical guideway. The hitherto known systems, which relate to optical scanning of an optical guideway by means of a light beam and which only transmit the signals "light" and "dark" with respect to detection of the optical guideway, are liable to disturbances and result in a too coarse or non-sensitive control. Therefore, it is suggested to scan the optical guideway by means of light pulses emitted in a predetermined frequency by sensors, whereby the intensity of the reflected light generates by means of an electronic evaluation unit a signal for controlling a steering or guiding mechanism. It is suggested to scan the optical guideway as an analog value by means of individual sensors arranged in a row and further process the determined values as digital values.

Abstract: An improved method of guiding the movement of an unmanned vehicle. A number of luminous points are arranged on a movement passage for the unmanned vehicle in the form of an arrangement pattern indicative of informations on the purpose of guiding. A visual sensor mounted on the unmanned vehicle detects the luminous points to reveive the informations on the purpose of guiding therefrom so that the movement of the unmanned vehicle is guided on the basis of the informations on the purpose of guiding which have been received in that way. According to a system of giving to the unmanned vehicle informations on the purpose of guiding in dependence on a manner of arranging luminous points, a number of informations on the purpose of guiding can be transmitted to the unmanned vehicle. Moreover, an area occupied especially by the marks for the purpose of guiding on the movement passage can be reduced much more than the conventional method.

Abstract: A tracking control method in which at least an objective lens within an optical pick-up is so controlled as to be driven in a radius direction of an optical disk having grooves (in a direction traversing track of the optical disk) relative to detectors of two-divided detector means for detecting reflected light quantities of reflected beam obtained by irradiating laser convergent beam of spot diameter defined by .lambda./NA on the optical disk in a manner in which a detection range is divided in the radius direction by estimating a difference information between the detected reflected light quantities, a range of the reflected beam irradiating the detectors being so set that the detectors detect the reflected light quantity equal to each other at a track-on state of irradiation point even though the objective lens moves in the radius direction.

Abstract: Apparatus for automatic tracking and contour measurement comprising electro-optical sensing apparatus mounted on a CNC machining head for providing an output indication of contours of an object in the precise frame of reference of the CNC machining head.

Abstract: A visual sensor system includes a moving object movable along a two-dimensional plane, and a one-dimensional array of photosensitive means fixedly mounted on the moving object. The photosensitive means are arranged in such a manner that the array is located within a first plane substantially perpendicular to a central axis of a line of sight and forms, within the second plane, a given angle with a line intersecting a second plane containing the central axis of the line of sight and substantially perpendicular to the two-dimensional plane.

Abstract: A method of patterning a perforated screen printing screen (9) having a lacquer coating filling its perforations (10), using a laser engraving device, includes the steps of locating the position of the locus of aligned perforations (10), aligning an engraving head (7) of the laser engraving device with the locus of the perforations (10) and then selectively actuating the laser to remove the lacquer individually from those perforations (10) which it is required to unblock.

Abstract: A print head position control system for a printer in which a print head moves along a track and in which a light source illuminates along the track and a photodetector receives the light to produce a control signal in proportion to the position of the print head in relation to the light. A print head mount electromechanically adjusts the position of the print head in response to the control signal, so that the path of the light automatically controls the print head path along the track.

Abstract: A method and apparatus for optically inspecting the geometry of a surface in an environment which is subject to the presence of external light noise perturbations. A beam of monochromatic light having a predetermined wavelength and a structured light pattern is projected onto the surface to thereby scatter the structured light beam and produce a scattered light beam which is thereafter separated into first and second scattered beam portions. The first scattered beam portion is passed through a first optical filter having a narrow bandwidth and a central wavelength corresponding substantially to the wavelength of the projected light, thereby providing a first optical output signal representative of the surface geometry and of external light noise perturbation.

Abstract: A tracking servo signal is generated for use in an optical disc pick-up system, being particularly advantageous for use when the depth of the pits is greater or less than one-fourth the wavelength of the light beam used to read the disc, in which case diffraction patterns formed by reflected light beams are not symmetric on a photo-detector and typically result in DC-shifted tracking error signals. A first tracking error signal is generated from selected output signals of a number of light-receiving areas of the photo-detector and a second tracking error signal is generated by combining output signals from these light-receiving areas in a pattern different than that used in generating the first tracking error signal. These two tracking error signals are combined so that the resultant signal forms a tracking servo signal that has substantially no DC component.

Abstract: In an optical pattern tracer which uses sample and hold circuits for signal processing filtering of the signal to reduce undershoot can be attained by manipulation of the sample and hold processing circuits. The present application varies the holding capacitor to produce a varied low pass filter effect.

Abstract: An image contour data generating apparatus comprises a digitizer for holding an original film having a section which is bounded by a particular contour. The digitizer serves for inputting approximate information regarding the position of the contour on the original film. The apparatus also includes an image sensor in the digitizer which is moved to the inputted approximate position of the contour for detecting the accurate image contour position at that position, an arithmetic device for calculating an absolute contour line position from the inputted approximate contour position data and from the accurate image contour position data obtained by the image sensor, and a memory for storing the contour position data obtained from the calculation. The apparatus is such that the original film is not moved from its location on the digitizer from the time when the approximate image contour information is inputted until after the accurate contour position is detected.

Abstract: Curve following apparatus for providing digital output signals indicative of the mathematical shape and/or location of a curve comprising a scanning means having a large number of individual sensors unitarily grouped together into a two dimensional array so as to define a viewing window, a driving mechanism for holding and driving the scanning means, and processing means for developing and transforming vector components from the output signal of said scanning means and for controlling the position of said scanning means.

Abstract: An optical disk storage access method using a fine and coarse actuators for positioning a light spot to an intended track on the disk, wherein a pulse is generated each time the light spot has traversed a track, the pulses are counted to determine the distance from the current spot position to a target track, the fine actuator is activated depending on the measured distance, and the fine and coarse actuators are operated in unison so that the light spot is positioned to the target track.

Abstract: A scanning unit for an optical disc record carrier includes a radiation-sensitive detection system having a plurality of detection elements on which is formed a reflected image of the scanning spot on the track structure of the record carrier. A tracking error signal is derived by combining the output signals of detection elements situated on respective sides of a boundary line between two halves of the detection system, and comparing with each other the combined signals from both halves. Several different such tracking error signals are derived, for boundary lines having different orietations with respect to the direction of the track instantaneously being scanned. The tracking error signal corresponding to a boundary line most nearly parallel to the direction of such track will be of greatest amplitude, and is selected as the tracking error signal used for controlling the scanning unit to follow the center line of such track.

Abstract: Method and a device for reading out optically recorded data from an optical recording medium having data recording regions defined by reference lines in stripe and plural data tracks arranged in parallel to each other and perpendicular to said reference lines. According to the present inventions, a drastic change in the position of a reference line at a given order within the sensing field is monitored from among plural reference lines covered by the field. If there is any drastic change, the order of the reference line for reading is modified so that the data track to be read can be accurately followed even if the field of the reading sensor is deviated in the direction of the data tracks. It also enables correct data reading by checking whether the position of the reference lines included in the field of the reading sensor is within the preset tolerance.

Abstract: In an optical line tracer sudden changes of velocity can cause instability and vibration. Means are provided to limit acceleration or deceleration to a specific rate of change. Speed change signals are processed through a ramp circuit which converts the step function signal to a ramp function before application.