DE19620419A1 - Optical contact free measurement of surface displacement - Google Patents
Optical contact free measurement of surface displacementInfo
- Publication number
- DE19620419A1 DE19620419A1 DE1996120419 DE19620419A DE19620419A1 DE 19620419 A1 DE19620419 A1 DE 19620419A1 DE 1996120419 DE1996120419 DE 1996120419 DE 19620419 A DE19620419 A DE 19620419A DE 19620419 A1 DE19620419 A1 DE 19620419A1
- Authority
- DE
- Germany
- Prior art keywords
- sensor
- laser
- brightness
- sensor elements
- point
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
Links
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 10
- 238000005259 measurement Methods 0.000 title claims abstract description 9
- 230000003287 optical effect Effects 0.000 title abstract description 3
- 238000000034 method Methods 0.000 claims abstract description 27
- 238000003384 imaging method Methods 0.000 claims abstract description 8
- 239000011159 matrix material Substances 0.000 claims abstract description 4
- 230000010355 oscillation Effects 0.000 claims 2
- 238000009826 distribution Methods 0.000 claims 1
- 238000005286 illumination Methods 0.000 claims 1
- 238000012360 testing method Methods 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 3
- 239000000463 material Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000005305 interferometry Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000004154 testing of material Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/161—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by interferometric means
- G01B11/162—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by interferometric means by speckle- or shearing interferometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/36—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/64—Devices characterised by the determination of the time taken to traverse a fixed distance
- G01P3/68—Devices characterised by the determination of the time taken to traverse a fixed distance using optical means, i.e. using infrared, visible, or ultraviolet light
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Electromagnetism (AREA)
- Power Engineering (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
In der Materialprüfung werden für viele Anwendungen mechanische Kennwerte über das statische und dynamische Dehnungsverhalten von Werkstoffen und Bauteilen benötigt. Dazu werden die Verschiebungen zwischen zwei in definiertem Abstand zueinander befindlichen Oberflächenpunkten mit mechanischen oder optischen Aufnehmern gemessen.Mechanical properties are used for many applications in material testing the static and dynamic expansion behavior of materials and components needed. To do this, the shifts between two at a defined distance surface points to each other with mechanical or optical Sensors measured.
Die derzeit zur Verfügung stehenden Meßaufnehmer lassen sich technologisch in zwei Gruppen aufteilen:The sensors currently available can be technologically divided into two Split groups:
- 1. Punktaufnehmer, die die Bewegung an nur einem oder wenigen Objektpunkten registrieren;1. Point transducers that measure the movement at only one or a few object points to register;
- 2. Flächenaufnehmer, die die Bewegung auf einer kompletten Fläche erfassen.2. Area sensors that record the movement over a complete area.
Eine für die automatische Prüfung und speziell für empfindliche Werkstoffe geforderte Prüfaufgabe ist die berührungslose Messung ohne das vorherige Aufbringen von Markierungen auf der Probenoberfläche.One required for automatic testing and especially for sensitive materials The test task is the contactless measurement without the previous application of Markings on the sample surface.
Die klassischen Punktsensoren messen mechanisch mittels Ansetzaufnehmern oder optisch durch Verfolgung von auf dem Objekt aufgebrachten Meßmarkierungen. The classic point sensors measure mechanically using clip-on sensors or optically by tracking measurement markings applied to the object.
Neuere Entwicklungen erlauben die flächenhafte, berührungslose und markierungsfreie Messung mittels Speckle-Interferometrie oder mittels Speckle-Korrelationstechniken. Diese Verfahren haben jeweils gemeinsam, daß sie aufgrund der sehr hohen zu verarbeitenden Datenmengen und der Datenerfassung mit Videotechnik relativ langsam sind. Für dynamische Messungen und zur Maschinenregelung können diese Verfahren daher nicht herangezogen werden.Recent developments allow the areal, contactless and Label-free measurement using speckle interferometry or Speckle correlation techniques. These methods have in common that they are due the very high amounts of data to be processed and data acquisition Video technology is relatively slow. For dynamic measurements and for These procedures cannot therefore be used for machine control.
Ziel dieser Erfindung ist es, die berührungslose und markierungsfreie Messung von Verschiebungen nur weniger Punkte mit großer Geschwindigkeit zu ermöglichen.The aim of this invention is the non-contact and marking-free measurement of Allow only few points to move at high speed.
Bei der Speckle-Korrelationstechnik wird eine Fläche mit Laserlicht beleuchtet und das Bild der Oberfläche mit einer Videokamera aufgenommen. Bei einer Bewegung der Probe verändert sich das Specklemuster. Durch den Vergleich der in beiden Zuständen aufgenommenen Specklemuster und Korrelationsrechnungen kann die Bewegung der Probenoberfläche an jedem Punkt ermittelt werden. Dieser Rechenvorgang ist sehr zeitaufwendig. Um eine ausreichend großen Meßbereich und hohe Empfindlichkeit zu erzielen, muß die Anzahl der aufgenommen Bildpunkte möglichst groß sein, so daß eine signifikante Geschwindigkeitssteigerung unmöglich ist.With the speckle correlation technique, a surface is illuminated with laser light and that Image of the surface taken with a video camera. With a movement of the The speckle pattern changes. By comparing the two The states of recorded speckle patterns and correlation calculations can Movement of the sample surface can be determined at every point. This Calculation process is very time consuming. To a sufficiently large measuring range and To achieve high sensitivity, the number of recorded pixels must be be as large as possible so that a significant increase in speed is impossible is.
Der Lösungsvorschlag basiert auf dem Speckle-Effekt. Die Oberfläche des Prüflings (1) wird von einem Laser (2) und einer Optik (3) mit Laserlicht beleuchtet und mittels einer Abbildungsoptik (4) auf einem oder mehreren lichtempfindlichen Sensorelementen (5) abgebildet. Im Gegensatz zu den o.g. flächenhaften Meßverfahren Verfahren wird allerdings lediglich ein kleiner Oberflächenbereich betrachtet. Dies bewirkt, daß sich das Specklemuster bei einer Dehnung des Bauteils kaum ändert, sondern im wesentlichen nur mit der Probenoberfläche verschoben wird. Die Abbildungsoptik (4) wird so eingestellt, daß der oder die Sensorelemente (5) möglichst nur einen oder wenige Speckles (6) erfassen. Verschiebt sich die Oberfläche (1), so verschiebt sich mit ihr die Position des Speckles (6) und die Helligkeit an jedem Sensorelement (5) ändert sich. Wenn Laserbeleuchtung, Abbildungsoptik und Sensorelement (im folgenden als Punktsensor (7) bezeichnet) um den gleichen Betrag mitbewegt werden, ändert sich die Helligkeit an jedem Sensorelement nicht oder nur unwesentlich (so lange, bis sich durch lokale Dehnungen das Specklemuster ändert). Der Betrag, um den der Punktsensor bewegt werden muß ist das Maß für die Verschiebung des betrachteten Objektpunktes.The proposed solution is based on the speckle effect. The surface of the test specimen ( 1 ) is illuminated with laser light by a laser ( 2 ) and optics ( 3 ) and imaged on one or more light-sensitive sensor elements ( 5 ) by means of imaging optics ( 4 ). In contrast to the two-dimensional measurement methods mentioned above, only a small surface area is considered. This has the effect that the speckle pattern hardly changes when the component is stretched, but is essentially only shifted with the sample surface. The imaging optics ( 4 ) are set so that the sensor element (s) ( 5 ) detect only one or a few speckles ( 6 ) if possible. If the surface ( 1 ) shifts, it moves the position of the speckle ( 6 ) and the brightness of each sensor element ( 5 ) changes. If the laser lighting, imaging optics and sensor element (hereinafter referred to as point sensor ( 7 )) are moved by the same amount, the brightness on each sensor element does not change or changes only insignificantly (until the speckle pattern changes due to local expansion). The amount by which the point sensor has to be moved is the measure for the displacement of the object point under consideration.
Die Verschiebevorrichtung des Punktsensors wird somit mittels eines (analogen oder digitalen) Prozessors (8) und einer Verfahreinrichtung (9) immer so geregelt, daß die Sensorelemente möglichst konstante Helligkeitswerte bzw. konstante Helligkeitsdifferenzen zwischen den Elementen aufweisen. The displacement device of the point sensor is thus always controlled by means of an (analog or digital) processor ( 8 ) and a displacement device ( 9 ) in such a way that the sensor elements have constant brightness values or constant brightness differences between the elements.
Im beschriebenen Verfahren wird daher im Gegensatz zur den Specklekorrelationsverfahren nicht die Bewegung der Speckle auf einer Sensormatrix ermittelt, sondern ein Speckle durch mechanisches Nachführen festgehalten. Da nun nur noch ein oder wenige Sensorelemente eingesetzt werden müssen und die Auswertung sowohl digital als auch analog durchgeführt werden kann, kann die Messung wesentlich schneller als die bekannten Verfahren erfolgen und auch für die Maschinenregelung eingesetzt werden.In the described method, therefore, in contrast to the Speckle correlation method does not involve moving the speckle on a sensor matrix determined, but held a speckle by mechanical tracking. Because now only one or a few sensor elements have to be used and the The evaluation can be carried out both digitally and analog Measurement take place much faster than the known methods and also for the Machine control can be used.
Falls nur ein Sensorelement eingesetzt wird, kann aus der Helligkeitsänderung nicht die Richtung der Verschiebung erkannt werden. Daher muß in diesem Fall der Punktsensor um das Optimum oszillieren, um auf diese Weise die Speckleposition nicht zu verlieren.If only one sensor element is used, the change in brightness cannot the direction of the shift can be detected. Therefore in this case the Point sensor oscillate around the optimum to achieve the speckle position not to lose.
Claims (18)
bei dem die zu messende Oberfläche mit einem Laserlichtbündel beleuchtet wird,
das Bild eines beleuchteten Punktes mittels einer geeigneten Optik auf einen oder mehrere Sensorelemente abgebildet wird, wobei
die Lichtintensität der einzelnen Sensorelemente registriert wird und bei einer Veränderung der Absoluthelligkeit des Einzelsensorelements oder der Absoluthelligkeiten der Sensorelemente oder der relativen Helligkeitsdifferenzen zwischen den einzelnen Sensorelementen Laserbeleuchtung und Sensorelement(e) so mechanisch verfahren werden, daß die Ausgangshelligkeitswerte oder -differenzen wieder erreicht werden,
wobei der mechanische Verfahrweg von Laserbeleuchtung und Sensorelement(en) ein Maß für die Verschiebung des beobachteten Oberflächenpunktes ist. 1. method for non-contact and marking-free measurement of surface displacements,
in which the surface to be measured is illuminated with a laser light beam,
the image of an illuminated point is imaged on one or more sensor elements by means of suitable optics, wherein
the light intensity of the individual sensor elements is registered and when the absolute brightness of the individual sensor element or the absolute brightness of the sensor elements or the relative brightness differences between the individual sensor elements laser illumination and sensor element (s) change, the mechanical movement is such that the initial brightness values or differences are reached again,
the mechanical travel path of laser lighting and sensor element (s) being a measure of the displacement of the observed surface point.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE1996120419 DE19620419A1 (en) | 1996-05-21 | 1996-05-21 | Optical contact free measurement of surface displacement |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE1996120419 DE19620419A1 (en) | 1996-05-21 | 1996-05-21 | Optical contact free measurement of surface displacement |
Publications (1)
Publication Number | Publication Date |
---|---|
DE19620419A1 true DE19620419A1 (en) | 1997-11-27 |
Family
ID=7794890
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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DE1996120419 Withdrawn DE19620419A1 (en) | 1996-05-21 | 1996-05-21 | Optical contact free measurement of surface displacement |
Country Status (1)
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DE (1) | DE19620419A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1152210A2 (en) * | 2000-04-26 | 2001-11-07 | Kabushiki Kaisha Toyo Seiki Seisakusho | Method and apparatus to measure amount of movement using granular speck pattern generated by reflecting laser beam |
EP1160538A1 (en) * | 2000-06-01 | 2001-12-05 | Mitutoyo Corporation | Speckle-image-based optical position transducer having improved mounting and directional sensitivities |
EP2641694A1 (en) * | 2012-03-23 | 2013-09-25 | Chung-Shan Institute of Science and Technology, Armaments, Bureau, Ministry of National Defense | Actuating apparatus, actuating system and method for actuating a working stage to move relative to a platform with high-precision positioning capability |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB973466A (en) * | 1962-02-07 | 1964-10-28 | Commissariat Energie Atomique | Device for detecting the position of a reflecting surface |
DE2710795B2 (en) * | 1976-03-23 | 1979-08-23 | Cem - Compagnie Electro-Mecanique, Paris | Method and device for measuring displacements or vibrations of a surface |
EP0129242A1 (en) * | 1983-06-20 | 1984-12-27 | Sumitomo Chemical Company, Limited | Tensile tester |
DE3821734A1 (en) * | 1987-06-29 | 1989-02-02 | Davy Mckee Poole | Device for determining the speed of a belt (tape), strip or the like |
DE3819085C1 (en) * | 1988-06-04 | 1989-12-07 | Bochumer Eisenhuette Heintzmann Gmbh & Co Kg, 4630 Bochum, De | Non-contact optical speed measurement of moving object - adjusting speed of polygon mirror so that detector of light spot on object receives reference speckle structure |
DE3632336C2 (en) * | 1985-10-16 | 1992-04-30 | Toshiba Kikai K.K., Tokio/Tokyo, Jp | |
DE4105270A1 (en) * | 1991-02-20 | 1992-08-27 | Max Planck Gesellschaft | OPTICAL WAY OR DIMENSION MEASUREMENT METHOD AND OPTICAL WAY OR DIMENSION METER |
JPH074928A (en) * | 1993-06-15 | 1995-01-10 | Shimadzu Corp | Strain measuring apparatus |
-
1996
- 1996-05-21 DE DE1996120419 patent/DE19620419A1/en not_active Withdrawn
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB973466A (en) * | 1962-02-07 | 1964-10-28 | Commissariat Energie Atomique | Device for detecting the position of a reflecting surface |
DE2710795B2 (en) * | 1976-03-23 | 1979-08-23 | Cem - Compagnie Electro-Mecanique, Paris | Method and device for measuring displacements or vibrations of a surface |
EP0129242A1 (en) * | 1983-06-20 | 1984-12-27 | Sumitomo Chemical Company, Limited | Tensile tester |
DE3632336C2 (en) * | 1985-10-16 | 1992-04-30 | Toshiba Kikai K.K., Tokio/Tokyo, Jp | |
DE3821734A1 (en) * | 1987-06-29 | 1989-02-02 | Davy Mckee Poole | Device for determining the speed of a belt (tape), strip or the like |
DE3819085C1 (en) * | 1988-06-04 | 1989-12-07 | Bochumer Eisenhuette Heintzmann Gmbh & Co Kg, 4630 Bochum, De | Non-contact optical speed measurement of moving object - adjusting speed of polygon mirror so that detector of light spot on object receives reference speckle structure |
DE4105270A1 (en) * | 1991-02-20 | 1992-08-27 | Max Planck Gesellschaft | OPTICAL WAY OR DIMENSION MEASUREMENT METHOD AND OPTICAL WAY OR DIMENSION METER |
JPH074928A (en) * | 1993-06-15 | 1995-01-10 | Shimadzu Corp | Strain measuring apparatus |
Non-Patent Citations (2)
Title |
---|
ARZT,R., RINGELHAU,H.: Optische Sensoren zur berührungslosen und schlupffreien Weg- und Geschwindigkeits-Messung an Landfahrzeugen. In: F&M Feinwerktechnik & Messtechnik, 86, 1978, 2, S.69-71 * |
Meßtechnik. In: Chemie-Ing.-Techn., 43.Jg., 1971, S.A1347,A1349 * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1152210A2 (en) * | 2000-04-26 | 2001-11-07 | Kabushiki Kaisha Toyo Seiki Seisakusho | Method and apparatus to measure amount of movement using granular speck pattern generated by reflecting laser beam |
EP1152210A3 (en) * | 2000-04-26 | 2002-06-12 | Kabushiki Kaisha Toyo Seiki Seisakusho | Method and apparatus to measure amount of movement using granular speck pattern generated by reflecting laser beam |
US6847910B2 (en) | 2000-04-26 | 2005-01-25 | Kabushiki Kaisha Toyoseikiseisakusho | Method and apparatus to measure amount of movement using granular speck pattern generated by reflecting laser beam |
US7165007B2 (en) | 2000-04-26 | 2007-01-16 | Kabushiki Kaisha Toyoseikiseisakusho | Method and apparatus for direct image pick-up of granular speck pattern generated by reflecting light of laser beam |
US7257510B2 (en) | 2000-04-26 | 2007-08-14 | Kabushiki Kaisha Toyoseikiseisakusho | Method and apparatus to measure amount of movement using granular speck pattern generated by reflecting laser beam |
KR100995287B1 (en) * | 2000-04-26 | 2010-11-22 | 가부시키가이샤 도요세이키 세이사쿠쇼 | Method and apparatus to measure amount of movement using granular speck pattern generated by reflecting laser beam |
EP1160538A1 (en) * | 2000-06-01 | 2001-12-05 | Mitutoyo Corporation | Speckle-image-based optical position transducer having improved mounting and directional sensitivities |
US6642506B1 (en) | 2000-06-01 | 2003-11-04 | Mitutoyo Corporation | Speckle-image-based optical position transducer having improved mounting and directional sensitivities |
EP2641694A1 (en) * | 2012-03-23 | 2013-09-25 | Chung-Shan Institute of Science and Technology, Armaments, Bureau, Ministry of National Defense | Actuating apparatus, actuating system and method for actuating a working stage to move relative to a platform with high-precision positioning capability |
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OM8 | Search report available as to paragraph 43 lit. 1 sentence 1 patent law | ||
OP8 | Request for examination as to paragraph 44 patent law | ||
8127 | New person/name/address of the applicant |
Owner name: ETTEMEYER AG, 89275 ELCHINGEN, DE |
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