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WO2014114663A1 - Dispositif optique et procédé pour déterminer par triangulation de deux caméras linéaires les coordonnées spatiales de surfaces d'objets macroscopiques - Google Patents

Dispositif optique et procédé pour déterminer par triangulation de deux caméras linéaires les coordonnées spatiales de surfaces d'objets macroscopiques Download PDF

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Publication number
WO2014114663A1
WO2014114663A1 PCT/EP2014/051210 EP2014051210W WO2014114663A1 WO 2014114663 A1 WO2014114663 A1 WO 2014114663A1 EP 2014051210 W EP2014051210 W EP 2014051210W WO 2014114663 A1 WO2014114663 A1 WO 2014114663A1
Authority
WO
WIPO (PCT)
Prior art keywords
line
scan cameras
series
plane
projector
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.)
Ceased
Application number
PCT/EP2014/051210
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German (de)
English (en)
Inventor
Gunther Notni
Peter KÜHMSTEDT
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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 Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of WO2014114663A1 publication Critical patent/WO2014114663A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/245—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using a plurality of fixed, simultaneously operating transducers
    • 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
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
    • G01B11/2545—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object with one projection direction and several detection directions, e.g. stereo

Definitions

  • the invention relates to a device for determining spatial coordinates of surfaces of macroscopic objects and to a method that can be carried out for determining spatial coordinates of a surface of a macroscopic object.
  • the three-dimensional measurement of macroscopic objects is i.a.
  • the advantage of active object lighting over approaches that work exclusively with ambient light lies in the pattern-dependent one- or one-to-one assignment of camera and / or camera
  • One area of three-dimensional measurement is the determination of coordinates in the case of moving objects or moving sensors, in which a very high speed of data acquisition has to be realized in order to avoid motion blur during the measurement. Also of importance is the very fast measurement of static measurement situations with frame rates that are not achieved today with conventional area cameras.
  • such known line scanners have a computer system which controls the projection and receives and processes the data from the camera.
  • the laser line is projected onto the object in the form of a projection plane. This plane strikes the measurement object, and the intersection line between object projection plane forms the laser line on the object.
  • the height information of the object is coded in the form of a lateral deflection of the line in the camera image.
  • the 3D coordinates are recorded along a line on the object. To record such a line, the camera information of the area camera must be read in each case. The height information of a line on the object is thus displayed as area information in the camera image.
  • a measurement object is located substantially in the x-y plane.
  • the projector as shown in Fig. 1, a line from the direction of the z-axis - ie in the direction opposite to the z-axis - is projected into the x-y plane, directly to the y-axis or parallel to the y-axis.
  • a projection beam or a fan of light is created, which spans a projection plane in the y-z plane.
  • the object is observed from a direction in the x-z plane, with an angle of the optical axis to the z axis of several degrees to about 80 °. By way of example, 20 ° are chosen.
  • the optical axis of the camera is in the x-z plane.
  • the camera observes the x-y plane and the measurement object located there.
  • Object and the y-z plane are captured. This is coded in the camera for each measuring point in an offset of the observed lines.
  • An intensity distribution of the type shown in FIG. 1 at the top right results in the camera plane.
  • the triangulation base is spanned by the camera and the projector. It lies in the x-z plane and outside the y-z plane.
  • the invention has for its object to provide a compact device for determining spatial coordinates of surfaces of macroscopic objects, with which the measurement of such surfaces in a relatively short time is possible. Also proposed is a corresponding method for determining spatial coordinates of a surface of a macroscopic object, which manages with extremely short measurement times.
  • the proposed device for determining spatial coordinates of surfaces of macroscopic objects comprises a line projector, two line scan cameras and a control and evaluation unit, wherein the control and evaluation unit is set up to carry out the following steps:
  • This device allows a measurement of three-dimensional contours and the determination of height and depth information of surfaces in a very short time. This results already from the fact that line cameras compared to surface cameras much larger rates bzg.
  • line scan cameras due to their small dimensions, in particular perpendicular to the respective image line, results in a very compact construction is also very efficient, because at least almost all recorded image information is also used in contrast to the conventional light-section method in which ultimately only the image information of a narrow strip of the respective image sensor corresponding to the narrow illuminated line are used.
  • the proposed method for determining spatial coordinates of a surface of a macroscopic object which comprises the following steps, is also advantageous.
  • Each taking a one-dimensional image of a strip illuminated by the line projector of the surface for each of these intensity distributions by each of two line scan cameras, so that each of the two line scan cameras each takes a one-dimensional image for each of the projected intensity distributions and for each pixel of an image line of the respective one Line camera is determined in each case a series of measured values, Determining mutually corresponding pixels of the two image lines of the two line scan cameras by correlating the series of one-dimensional images taken with the two line scan cameras or the series of measured values determined by the two line scan cameras
  • the surface of the object is scanned by carrying out said steps for a sequence of different projection directions, such that said plane is tilted about an axis lying in this plane and oriented perpendicular to a main projection direction of the line projector becomes.
  • a contour of the object can be detected not only along a line, but at least within certain limits over the entire surface of the object.
  • the proposed device can accordingly be designed as a line scanner, which is designed to execute the said steps for a sequence of different projection directions, so that said plane is tilted about said axis.
  • the intensity distributions may e.g. in the form of (l + cos) -shaped intensity distributions or of statistical patterns or of bacon patterns.
  • patterns of this type are suitable for enabling the necessary identification of corresponding pixels-meaning homologous points in the two image lines of the two line scan cameras-with a not too large number of projected intensity distributions.
  • the control and evaluation unit can be set up to use the line projector for the projection of the intensity distributions in the form of
  • the line projector has a laser and a diffuser for generating the intensity distributions or a digital one
  • Projection system or for generating the intensity distributions means discrete single-point pattern or by means of a sliding slide and a fixed projection optics is executed.
  • the intensity distributions can thus be generated in particular by means of a laser and a diffusing disk for generating / shaping speckle or by means of a digital projection system or by means of discrete single point patterns or by means of a displaceable slide and a fixed projection optics.
  • the device or the line scanner thus forms a substantially two-dimensional arrangement.
  • FIG. 2 shows a schematically illustrated line scanner of the proposed type with a line projector and two line scan cameras in a perspective view
  • Fig. 3 shows the line scanner of Fig. 2 in a plan view of a surface to be measured
  • Fig. 4 shows the same line scanner in a viewing direction perpendicular to a
  • the line scanner shown in FIGS. 2 to 4 forms a device for determining spatial coordinates of a surface of an object 1 shown here in transparent form. This surface lies approximately in the x-y plane.
  • the line projector 2 whose main projection direction is parallel to the z-axis of the coordinate system and opposite to the z-axis of the coordinate system, has a line projector 6 and two line scan cameras 7 and a control and evaluation unit 8.
  • the control and evaluation unit 8 is shown only in FIG.
  • Each of the line scan cameras 7 has, in addition to a simple imaging optical unit 9, an image line 10 with a multiplicity of pixels not shown individually and arranged in a row.
  • the line projector 6 projects one-dimensional intensity distributions 12, which respectively illuminate only one line on the object 1.
  • the surface of the object 1 can be scanned with the line scanner, for example, by this light fan is pivoted about an axis lying parallel to the y-axis in the x direction, as shown in Fig. 2 by a double arrow.
  • One of the various successively projected intensity distributions 12 is shown in FIG. 4 along a line projector illuminated
  • Strip indicated by a curve, wherein a location-dependent intensity is illustrated by a survey of this curve over the illuminated strip in the z direction.
  • the correspondingly programmed control and evaluation unit 8 controls the line projector 6 in such a way that it projects a series of different intensity distributions 12 onto the surface of the object 1 within a plane which is constant for this series. So is each along a cutting line of the last-mentioned plane and the surface of the object 1, a line of inhomogeneous intensity is projected onto the surface.
  • the line scan cameras 7 are simultaneously controlled by the control and evaluation unit 8, which is also correspondingly set up, so that each of the line scan cameras 7 receives a one-dimensional image of the strip of the surface illuminated by the line projector 6 for each of the aforementioned intensity distributions 12 For each pixel of the BÜdzeile 10 of the respective line scan camera 7 is determined in each case a series of measured values.
  • control and evaluation unit 8 determines corresponding pixels of the two image lines 10 of the two line scan cameras 7 and evaluation unit 8 calculates the spatial coordinates for a plurality of points of the intersection line of the projected intensity distributions 12 with the surface of the object 1 by triangulation on the basis of the thus determined mutually corresponding pixels of the two image lines 10 of the two line scan cameras 7.
  • the surface is scanned with the line scanner, for example by carrying out said steps for a sequence of different projection directions.
  • said plane, within which the intensity distributions 12 are projected is tilted about the already mentioned axis lying in this plane and oriented perpendicular to the main projection direction of the line projector 6.
  • the intensity distributions 12 are projected, for example, in the form of ⁇ 1 + cos) -shaped intensity gradients or in the form of statistical patterns or in the form of speckle patterns or in the form of discrete single-point patterns.
  • the line projector 6 can generate the intensity distributions 12 by means of a laser and a diffusing screen or by means of a digital projection system or by means of a slide displaceable for scanning the surface and a fixed projection optics.
  • two line scan cameras 7 are used instead of an area camera for recording the object shape along a line.
  • the line scan cameras 7 are arranged as follows:
  • the optical axis lies in each case in a common plane, for example in the y-z plane.
  • the camera viewing direction is in each case rotated against the z-axis by a few degrees up to possibly about 80 °.
  • the triangulation base between the two line scan cameras lies in the y-z plane.
  • the projector instead of the approximately constant intensity along its line, as provided in the classical line projector, a sequence of different, for example statistical intensity distributions 12. Also possible are other forms of intensity distribution 12 such as (l + cos) -shaped distributions, dot patterns or Intensity distributions 12 formed by the speckle pattern.
  • the intensity variation takes place transversely to the propagation direction of the laser line or the projected line.
  • the two line scan cameras 7 each record the series of intensity distributions 12. From the correlation of the images of the series in both line scan cameras 7, one pixel each of a line scan camera 7 can then be assigned to an interpolated pixel of the second line scan camera 7.
  • the thus associated pixels which have elsewhere been designated as corresponding to each other, may be regarded as homologous points.
  • the take-up speed is given instead of the maximum frame rate of a surface camera by the maximum frame rate of two comparatively fast line scan cameras 7.
  • the take-up speed is given instead of the maximum frame rate of a surface camera by the maximum frame rate of two comparatively fast line scan cameras 7.
  • a typical number of 6 to 20 shots for a series results in a speed advantage of about a factor of 10 to 100.
  • the possible application examples of this invention are in the area of three-dimensional surface measurement or coordinate determination of macroscopic objects by using active pattern projection, for example by projection of gray scale distributions on the basis of statistical patterns.
  • the entire intensity information taken by the camera is used for the coordinate determination instead of the narrow illuminated line in the area camera.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne un dispositif et un procédé pour déterminer les coordonnées spatiales de surfaces d'objets macroscopiques (1). Le dispositif proposé comporte un projecteur de lignes (6), deux caméras linéaires (7) et une unité de commande et d'évaluation (8), l'unité de commande et d'évaluation (8) étant conçue pour effectuer les étapes suivantes : - pilotage du projecteur de lignes (6) de telle sorte que celui-ci projette une série de différentes répartitions d'intensité (12) à l'intérieur d'un même plan pour cette série, - pilotage des caméras linéaires (7), de telle sorte que chaque caméra linéaire (7) enregistre, à chaque fois pour chacune de ces répartitions d'intensité (12), une image unidimensionnelle, de telle sorte que, pour chaque pixel d'une ligne d'image (10) de la caméra linéaire (7) en question, une série de valeurs de mesure soit déterminée, - détermination, pour les deux lignes d'image (10) des deux caméras linéaires (7), des pixels qui se correspondent par corrélation des séries de valeurs de mesure déterminées à l'aide des deux caméras linéaires (7) et - calcul par triangulation des coordonnées spatiales pour une pluralité de points d'une sécante des répartitions d'intensité projetées (12) avec une surface d'objet.
PCT/EP2014/051210 2013-01-23 2014-01-22 Dispositif optique et procédé pour déterminer par triangulation de deux caméras linéaires les coordonnées spatiales de surfaces d'objets macroscopiques Ceased WO2014114663A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102013201061.3A DE102013201061A1 (de) 2013-01-23 2013-01-23 Vorrichtung und Verfahren zum Bestimmen räumlicher Koordinaten von Oberflächen makroskopischer Objekte
DE102013201061.3 2013-01-23

Publications (1)

Publication Number Publication Date
WO2014114663A1 true WO2014114663A1 (fr) 2014-07-31

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DE (1) DE102013201061A1 (fr)
WO (1) WO2014114663A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113074669A (zh) * 2016-10-17 2021-07-06 维蒂克影像国际无限责任公司 具有闪光对准的激光投影仪

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113188484B (zh) * 2021-04-16 2022-11-29 北京科技大学 一种热轧卷头部轮廓面积检测方法

Citations (6)

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JPS597204A (ja) * 1982-07-06 1984-01-14 Mitsubishi Electric Corp 視覚装置
JPS6125003A (ja) * 1984-07-13 1986-02-03 Hitachi Zosen Corp 形状計測方法
US4834530A (en) * 1986-04-18 1989-05-30 Tokyo Kogaku Kikai Kabushiki Kaisha Shape measuring apparatus
US6466305B1 (en) * 1999-05-24 2002-10-15 Lmi Technologies Inc. High speed laser triangulation measurements of shape and thickness
EP2019281A1 (fr) * 2007-07-20 2009-01-28 Sick Ag Capteur en 3D et procédé destiné au fonctionnement d'un capteur en 3D
WO2011044660A1 (fr) * 2009-10-17 2011-04-21 Hermary Opto Electronics Inc. Procédé et appareil d'imagerie améliorée

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DE19928341C2 (de) * 1999-06-21 2002-06-20 Inb Vision Ag Verfahren zur dreidimensionalen optischen Vermessung von Objektoberflächen
US7103212B2 (en) * 2002-11-22 2006-09-05 Strider Labs, Inc. Acquisition of three-dimensional images by an active stereo technique using locally unique patterns
CA2435935A1 (fr) * 2003-07-24 2005-01-24 Guylain Lemelin Numeriseur tridimensionnel optique a zone de non-ambiguite elargie
DE102007060263A1 (de) * 2007-08-16 2009-02-26 Steinbichler Optotechnik Gmbh Vorrichtung zur Ermittlung der 3D-Koordinaten eines Objekts, insbesondere eines Zahns
DE102011008655A1 (de) * 2011-01-14 2012-07-19 Inb Vision Ag Vorrichtung und Verfahren zur dreidimensionalen optischen Vermessung von Oberflächen

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS597204A (ja) * 1982-07-06 1984-01-14 Mitsubishi Electric Corp 視覚装置
JPS6125003A (ja) * 1984-07-13 1986-02-03 Hitachi Zosen Corp 形状計測方法
US4834530A (en) * 1986-04-18 1989-05-30 Tokyo Kogaku Kikai Kabushiki Kaisha Shape measuring apparatus
US6466305B1 (en) * 1999-05-24 2002-10-15 Lmi Technologies Inc. High speed laser triangulation measurements of shape and thickness
EP2019281A1 (fr) * 2007-07-20 2009-01-28 Sick Ag Capteur en 3D et procédé destiné au fonctionnement d'un capteur en 3D
WO2011044660A1 (fr) * 2009-10-17 2011-04-21 Hermary Opto Electronics Inc. Procédé et appareil d'imagerie améliorée

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113074669A (zh) * 2016-10-17 2021-07-06 维蒂克影像国际无限责任公司 具有闪光对准的激光投影仪

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