+

WO1992003807A1 - Etalonnage d'un dispositif de determination de position a balayage rotatif - Google Patents

Etalonnage d'un dispositif de determination de position a balayage rotatif Download PDF

Info

Publication number
WO1992003807A1
WO1992003807A1 PCT/US1991/006007 US9106007W WO9203807A1 WO 1992003807 A1 WO1992003807 A1 WO 1992003807A1 US 9106007 W US9106007 W US 9106007W WO 9203807 A1 WO9203807 A1 WO 9203807A1
Authority
WO
WIPO (PCT)
Prior art keywords
effective
sin
reference objects
sensor
rotation
Prior art date
Application number
PCT/US1991/006007
Other languages
English (en)
Inventor
Marc D. Donner
Ephraim Feig
Original Assignee
International Business Machines Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Business Machines Corporation filed Critical International Business Machines Corporation
Publication of WO1992003807A1 publication Critical patent/WO1992003807A1/fr

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/042—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means
    • G06F3/0421—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means by interrupting or reflecting a light beam, e.g. optical touch-screen
    • G06F3/0423—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means by interrupting or reflecting a light beam, e.g. optical touch-screen using sweeping light beams, e.g. using rotating or vibrating mirror

Definitions

  • the present invention generally concerns coordinate-data input devices, and more particularly concerns the calibration of coordinate-data input devices of the rotationally scanned directional sensor type.
  • Detecting the interruption of a scanning beam of light by an object can be used to provide information about the location of the object. Specifically, the orientation of the light beam at the time of an interruption event gives the orientation of the object measured from an origin defined by an effective source of the light beam. If two scanning light beams from effective sources whose positions are known are interrupted by an object, the position of the object can be determined by triangulation from the respective orientations of the two beams at the times of the respective interruption events, provided that the position of the object is not colinear with a straight line extending through the effective sources of the two beams.
  • a coordinate-data input device employing two rotational scanned light beams for determining digital data which encodes the coordinates of the position of an object in a work area swept by the scanned beams is disclosed in United States patent No. 4,642,422 to Garwin and Levine.
  • each of the two scanning light beams was produced by a rotating beam-scan mirror reflecting a fixed light.
  • the axis of rotation of the two beam-scan mirror constituted an effective source position of the scanning light beam.
  • the two rotating mirrors were positioned near adjacent corners of the generally rectangular work area.
  • a straight line extending between the axes of rotation of the two beam-scan mirrors defined a measurement base line of the device.
  • the scanning light beams from the rotating beam-scan mirrors intersected the object, which caused light-variation events which were detected by the device.
  • the time of a lightvariation event could be used to determine an apparent angle of rotation a beam-scan mirror which defined an intersection angle between the measurement base line and the light beam intersecting with the object.
  • Such rotation angles from the two beam-scan mirrors together with the distance between the axes of rotation of the two beam-scan mirrors could be used in a trigonometric calculation to provide coordinate values for the location of the object in the work area.
  • a calibration procedure was used in the coordinate-data input device of the '422 patent to correct for certain sys tematic errors - referred to as angle "index errors" corresponding to non zero angles between the light beam and the measurement base line at a scan- start time which a control system of the device took as the time the light beam coincided with the base line.
  • the calibration procedure involved positioning three calibration-targets at known relative positions in the work area of the device. According to the '422 patent, the three calibration targets could be positioned in a colinear arrangement, but need not be.
  • a method for detecting and correcting an angle index error associated with either scanning light beam was disclosed in the patent which involved using the event times at which each scanning light beam intersects the three calibration targets, the time interval for the beam to complete one full revolution, and the relative positions of the three calibration targets.
  • the calibration procedure of the '422 is effective to determine and correct angle index errors in rotationally scanned beam-interruption coordinate data-input devices which arise from many sources, the procedure assumes that the rotational velocity of each rotating beam-scan mirror is constant over a full revolution of the mirror, which may not always be the case in certain coordinate-data input devices. Variations in the rotational velocity of a beam-scan mirror which are periodic over each revolution can be one source of angle index errors in a rotationally scanned beam-interruptions coordinate-data input device. Such periodic variations in rotational velocity can also render the calibration procedure of the '422 patent not fully effective to determine and correct such errors.
  • a preferred example of such an effectively rotating directional sensor may involve a rotating mirror in cooperation with fixed optical elements such as a laser, beam splitter and photodetector to form a rotationally-scanned light beam interruption coordinate-data input device for a computer or other digital data processor.
  • the effective angular velocity and the effective center of rotation of the sensor can be determined from the known distance between adjacent reference objects and the measured time intervals between detection of adjacent pairs of reference objects by the effectively rotating directional sensor. More specifically, the effective angular velocity is first determined as a solution of a mathematical equation. From the effective angular velocity thus determined together with the measured time intervals and the known distance between adjacent reference objects, the effective center of rotation of the sensor is determined.
  • the invention can be used to advantage to calibrate a twobeam rotationally-scanned light-beam interruption coordinate-data input device of the type disclosed generally in the United States patent No. 4,642,422 discussed above and incorporated in the present specification by reference.
  • the four reference objects are cylindrical stubs projecting at essentially equal - distance intervals from a ruler - like calibration strip.
  • the preferred calibration strip can be placed in the work area of a coordinate-data input device.
  • Preferred embodiments of the invention are essentially insensitive to any variations in the rotational velocity of the effective source of the rotationally scanned light beam in such devices over portion's of the rotational scan which are directed outside of the work area in which light-beamvariation events occur.
  • Figure 1 is a schematic drawing of a work area of a two-beam rotationally scanned light-beam interruption coordinatedata input device which can be calibrated by a preferred embodiment of the present invention.
  • Figure 2 illustrates four reference objects positioned on the work area of the coordinate-data input device of Figure 1 and certain angles defined between the reference objects and the effective source of one of the two rotationally scanned light beams of the device.
  • a rotationally-scanned lightbeam-interruption coordinate-data input device includes a first rotatable beam-scan mirror 1 and a second rotatable beam scan mirror 2.
  • a base line 3 extended between the axes of rotation of the two beam-scan mirrors 1, 2.
  • Beams of light from corresponding first and second stationary light sources (not shown) impinge upon the first and second beamscan mirrors 1 and 2 to produce first and second rotationally-scanned light beams 7 and 8.
  • Rotation of each beam-scan mirror 1, 2 cause the corresponding rotationallyscanned light beam 7, 8 to sweep across a generally rectangular work area 5.
  • the work area 5 is bounded by a perimeter 6.
  • the coordinate-data input device includes a beam intersection-event detector (not shown) located outside of the work-area perimeter 6 for detecting the times at which a rotationally-scanned light-beam 7, 8 intersects a stylus 4 or other object placed in the work area 5.
  • reference objects 11, 12, 13, 14 are placed in the work area 5 at essentially equal-distance intervals along a substantially straight line.
  • the rotation axis of the first beam-scan mirror 1 is located at a position indicated by M.
  • the distance between adjacent reference objects is denoted U in Figure 2 and is known.
  • the unknown distances from the beam-scan mirror 1 to the four reference objects 11-14 are denotedj .
  • Three angles ⁇ 1 , ⁇ z , ⁇ 3 are defined by three adjacent pairs of reference objects and the rotation axis of the mirror 1.
  • f( ⁇ ) sin ⁇ ( ⁇ 1 + ⁇ 2 ) sin ⁇ ( ⁇ 2 + ⁇ 3 ) - 4 sin ⁇ 1 sin ⁇ 3 .
  • a root of f in ⁇ can be solved numerically.
  • a NewtonRaphson procedure is particularily preferred to determine a root of f .
  • the distance d 1 can then be determined from:
  • the coordinates of the position M are then readily determined in a coordinate frame defined relative to the reference objects.
  • An analagous determination can be made of the coordinates of the position of the rotation axis of the beam-scan mirror 2 in the same coordinate system.
  • the calibration procedure can then be completed as described in the United States patent No. 4,642,422 incorporated by reference and angle index errors corrected for.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

Un procédé d'étalonnage permettant de déterminer la position exacte et la vitesse angulaire effective d'un détecteur (1) directionnel rotatif consiste à placer quatre objets de référence (11, 12, 13, 14) pouvant être détectés par le détecteur directionnel (1) à des intervalles sensiblement égaux mesurés le long d'une ligne droite. Les quatre objets de référence sont positionnés par rapport au détecteur directionnel (1) de sorte que chacun des objets peut être détecté individuellement à son tour au cours de la rotation effective du détecteur. Le procédé d'étalonnage consiste à détecter chacun des quatre objets de référence à l'aide du détecteur (1) directionnel rotatif afin de déterminer trois intervalles de temps appelés ν1, ν2, ν3 correspondant au temps écoulé entre la détection des paires adjacentes d'objets de référence. On détermine ensuite une vitesse de rotation α pour laquelle l'expression sin α(ν1+ν2) sin α(Ν2+ν3) - sin αν1 sin αν3 est sensiblement égale à zéro. Le centre exact de rotation du détecteur est déterminer de manière trigonométrique à partir de la vitesse angulaire effective, des intervalles de temps mesurés, et de la distance entre les objets de référence adjacents (11, 12, 13, 14).
PCT/US1991/006007 1990-08-22 1991-08-22 Etalonnage d'un dispositif de determination de position a balayage rotatif WO1992003807A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US57146690A 1990-08-22 1990-08-22
US571,466 1990-08-22

Publications (1)

Publication Number Publication Date
WO1992003807A1 true WO1992003807A1 (fr) 1992-03-05

Family

ID=24283827

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/006007 WO1992003807A1 (fr) 1990-08-22 1991-08-22 Etalonnage d'un dispositif de determination de position a balayage rotatif

Country Status (1)

Country Link
WO (1) WO1992003807A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000067065A1 (fr) * 1999-05-04 2000-11-09 Lockheed Martin Missiles And Space Company Dispositif de metrologie optique pour la mesure angulaire de la precision d'un miroir de pointage
WO2014125272A1 (fr) * 2013-02-13 2014-08-21 Light Blue Optics Ltd Systèmes de détection de contact

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5004870A (en) * 1990-04-11 1991-04-02 Osborn John J Polar co-ordinate digitizer

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5004870A (en) * 1990-04-11 1991-04-02 Osborn John J Polar co-ordinate digitizer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000067065A1 (fr) * 1999-05-04 2000-11-09 Lockheed Martin Missiles And Space Company Dispositif de metrologie optique pour la mesure angulaire de la precision d'un miroir de pointage
WO2014125272A1 (fr) * 2013-02-13 2014-08-21 Light Blue Optics Ltd Systèmes de détection de contact

Similar Documents

Publication Publication Date Title
US4788441A (en) Range finder wherein distance between target and source is determined by measuring scan time across a retroreflective target
US4720869A (en) Hand dimension verification
US6473167B1 (en) Position and orientation determination using stationary fan beam sources and rotating mirrors to sweep fan beams
US5267014A (en) Position and orientation measurement device
US5059789A (en) Optical position and orientation sensor
US5026998A (en) Shaft alignment checking method
US5298737A (en) Measuring apparatus for determining the position of a movable element with respect to a reference
US4642422A (en) Calibration of a scanning light interrupt type of data input interface
JPS61260322A (ja) 位置決めシステム
JPS61128111A (ja) 測定チヤートを備えた対象物の角度変位の測定方法
RU2275652C2 (ru) Способ локации источника излучения и устройство для его реализации
US5283396A (en) Calibration of a rotationally scanning position-tracking device
WO1992003807A1 (fr) Etalonnage d'un dispositif de determination de position a balayage rotatif
US5600123A (en) High-resolution extended field-of-view tracking apparatus and method
JP2945467B2 (ja) 機械高測定装置
JP3928213B2 (ja) ３次元計測方法及び装置
DE69733647D1 (de) Winkelmessvorrichtung
JPH01188254A (ja) 非接触倣いデジタイジング方法
EP0068638B1 (fr) Dispositif de mesure d'angles
JP2578842B2 (ja) 光学式方位測定装置による方位測定方法及びその方位測定方法に用いる装置
JPH02272310A (ja) 回転角度測定装置
GB2267340A (en) Optical system for measuring surface curvature using a rotatable mirror
SU896649A1 (ru) Устройство дл считывани графической информации
JPH0449047B2 (fr)
JPS63238422A (ja) 船体位置決めシステム

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE

COP Corrected version of pamphlet

Free format text: PAGE 1/1,DRAWINGS,ADDED

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载