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
• • 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
  • G01B11/2504—Calibration devices
• • 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
  • G01B11/2518—Projection by scanning of the object

Definitions

• the present invention relates to a method and a device for measuring a strand or sheet metal rolling profile with simultaneous calibration of laser light section sensors relative to each other according to claim or claims 16 and 17.
• laser light section sensors and references / reference markers are preferably on a circular device more laser light section sensors and references / reference markers to For example, a continuously to be measured strand or Blechwalzprofil arranged around, so that at the same time the strand or sheet rolling profile and the references / reference markers can be measured.
• the laser light section sensors can be easily recalibrated during a production process.
• DE 03 28 523 describes a method and a measuring device for a contactless measurement of a surface contour of a test specimen according to a laser-based light-section method (triangulation principle), such as for non-contact measurement of a rail profile for railways.
• a laser-based light-section method such as for non-contact measurement of a rail profile for railways.
• a laser line which is projected by light section sensors on the rail profile
• a plurality of reference markers between the rail profile and the respective sensor are arranged, wherein the reference markers lie in a plane and have a known distance from each other.
• the reference markers measured by means of the camera system are used to calculate a transformation matrix in order to equalize the image of a measuring line of the rail profile.
• the exact adjustment of the lying in a plane reference marker in the plane of a transmitted laser beam is, however, difficult and only intended for a solid composite of the light section sensors and the reference markers.
• No. 7,679,757 describes an apparatus and a method for a non-contact measurement of a surface contour according to the laser-based light-section method, for example of an extruded profile, which is pushed by a sensor device.
• the sensor device allows the measurement of the surface of the
• One or more sensors are mounted on a ring-like device, so that the
• Measure bar or rail profile from all sides based on its surface can be.
• the sensors are arranged radially, along a circular arc and directed inwards onto the extruded profile.
• the calibration of the sensor device takes place at times with the introduction of a special calibration element, which, however, can not occur during a production process.
• DE 100 17 463 describes a device and a method for the non-contact measurement of a surface contour according to the laser-based light-section method, in which the object to be measured is measured simultaneously with fixed reference markers.
• the image is obtained from the object to be measured and at the same time from the fixed reference markers by a semitransparent mirror.
• the fixed reference markers are to be held in a defined and constant spatial position to the sensors.
• DE 690 03 090 describes an apparatus and a method for the calibration of a movable laser light-slit sensor, which is attached, for example, to a robot arm and is moved around a specimen for measurement purposes.
• a defined calibration object of known dimensions is placed at a defined location in the room and scanned in order to then use these measured values
• US Pat. No. 7,679,757 B1 describes a 360-degree measuring system consisting of laser light-section sensors which are arranged in a circle around, for example, an extruded profile and measure it.
• the measuring system can be calibrated by a calibration object, which is briefly introduced into the middle of the common measuring range.
• the measuring system is also designed to recognize a known profile and to output associated measured values relative thereto.
• US 2004 0 202 364 A1 describes a calibration object or a reference object and a method for three-dimensional calibration of a measuring system consisting of a stereo photography unit which is moved around the measurement object together with the calibration object arranged in the image.
• Reference Object has a plurality of reference points, each of which at least six can be seen from each lateral position
• the sensor (s) should remain as inexpensive as possible and accurate in spite of temperature fluctuations in their measurement results.
• the temperature fluctuations affect the measurement results mainly as an offset and less than scaling error, which is essentially due to a temperature-induced change in angle of a laser beam.
• the required accuracy is known to be ensured by periodic calibrations over time. For this purpose, the production process by the calibration but desirably not be interrupted.
• an object of the present invention is to provide a method and a measuring device based on a laser Licht4.000meßhabilit for a continuous measurement of a surface of a guided through the measuring device test specimen, such as an extruded profile, wherein during the measurement of the specimen and periodic
• the measuring device preferably measures the surface of the specimen, such as the continuous extruded profile, from all sides or parts thereof.
• a further object of the present invention is to be able to use preferably simple and cost-effective laser light section sensors and to largely compensate for temperature and material propagation fluctuations by means of a suitable calibration in order to comply with the required measuring tolerances.
• a calibration of the raw image data from the second position in relation to the raw image data from the first position allows without a
• Measuring device is arranged, is shaded.
• an absolute position of the reference marker has no influence on the measurement result.
• Measuring range is generated by shading is not limited, and yet a calibration of the laser light section sensor is made possible at a position with respect to the adjacent position.
• temperature and aging influences on a mechanical structure or on one of the laser light section sensors of the measuring device, which cause an offset of the measured values, can be compensated in this way simply and quasi continuously, computationally.
• Fig. 1 is a perspective view of one based on the laser
• Light-section method for measuring the surface of an extruded profile which is pushed from a rolling device through the measuring device ..
• FIG. 3 shows the cross section of the extruded profile, which differs from that of FIG. 2
• Fig. 4 shows the cross section of the extruded profile with the around it
• Fig. 5 shows the cross section of the extruded profile with the around it
• FIG. 1 shows a three-dimensional view of a preferred measuring device 1 for measuring a test specimen and in particular an extruded profile 2, which is passed through the measuring device 1 therethrough.
• the measuring device 1 several or at least one movable, controllable laser light section sensor S1-S4 are preferably arranged on a circular device 11 around the extruded profile 2 so as to be aligned with the center where the extruded profile 2 is located, around the surface 20 of the extruded profile 2 as a cross section to detect wholly or partially by measurement
• the circular device 11 for measuring the extruded profile preferably several laser light section sensors S1-S4 are used, their initially not be known exact position because the exact positions can be calculated later by a calibration ..
• An arrangement of the laser light section sensors S1-S4 along the circular device 11 takes place so that as large as possible or ., A relevant part of the surface 20 of the extruded profile 2 is detected by the laser light section sensors S1 -S4 metrologically,. Thereafter, a number used and the arrangement of the laser light section sensors S1-S4 depends.
• the detection of the surface 20 by the laser light section sensors S1-S4 is effected such that the respective laser light section sensor S1-S4 emits a laser light bundle lying in a plane, which is projected onto the surface 20 of the extruded profile 2 as a laser light section , and its reflected light in turn detected by measurement.
• the laser light sections are preferably generated so that they lie substantially in a common plane or that their respective laser light slices by one to three widths of a
• Laser beam are parallel offset so far that they just do not disturb each other for a measurement.
• the common level is preferred
• Laser light sections designed so that it is substantially perpendicular to the extruded profile (2).
• the measuring device 1 which comprises only one or a few laser light-section sensors, they can be located on the
• Device 1 are moved together by an angle Phi, thereby to generate a different illumination or another Meßer chargeds Scheme and ultimately to be able to detect undercuts a profile better.
• the reference markers 31-34 are constantly installed in the preferred embodiment in the measuring device 1 so that they shade as possible nothing of the extruded profile 2 to be measured.
• the extruded profile 2 is passed through the measuring device 1 in the Z direction and preferably measured from all sides, the extruded profile 2 can be measured as a quasi SD surface profile.
• an extruded profile 2 parts of the surface profile 20 are shaded, as is the case in Fig. 3 and Fig. 4, these parts can not be measured by laser light section sensors S1-S4
• the extruded profile 2 which is measured by the laser light section sensors, thus lies in the XY plane, whereby the illuminated outer edges can be detected by measurement.
• the extruded profile 2 is passed through the measuring device 1 in quasi-continuous measurement, a three-dimensional surface image thereof is obtained.
• Fig. 2 is a schematic side view of a preferred embodiment
• a preferred common Meßer Pacificly facing laser light section sensors S1-S4.
• the extruded profile 2 is shown as a cross section with the outwardly facing surface segments 21-24.
• the surface segments 21-24 essentially form the surface 20 of the extruded profile 2 when there are no shadows, which in this example of the extruded profile is also not the case.
• the reference markers 31-34 are preferably formed as metal strips and on an outer region 4 of the common
• Measuring detection range arranged radially inwardly, so that the
• Extruded profile 2 is not obscured by them and yet they are all at least partially in the measurement detection range of all laser light section sensors S1-S4.
• the circular device 11, on which the laser light section sensors S1-S4 are arranged, has in the preferred embodiment an opening 12, through which an extruded profile can also be introduced from the side. But this opening 12 is not necessarily necessary because the extruded profile 2 continuously through the
• Measuring device 1 can be passed without intermittently for the purpose of calibration, the extruded profile 2 are taken out and then again
• the measuring device 1 this can for example be arranged at one end of a rolling device or at another production plant for a production of the extruded profile 2.
• the calibration of the measuring device with the respective laser light section sensors S1-S4 is preferably carried out so that existing references in the extruded profile 2 to be measured and additional
• Reference markers 31-34 which are detected jointly by the laser light section sensors S1-S4 from the respective measurement perspectives, are used to superimpose image data of the respective laser light-slit sensors S1-S4 which contain at least two references or reference markers together
• the superimposition of the image data by rotation and displacement in the x / y direction is carried out in such a way that the references and reference markers 31-34 are superimposed optimally superposed on one another.
• a least-mean-square method is preferably used, from which a respective transformation matrix for correction and to an optimum
• Transformation matrix are raw image data of the corresponding laser light section sensor S1-S4 converted into calibrated image data, which then in a common coordinate system correctly. calibrated to be mapped.
• references in the extruded profile 2 and as reference markers 31-34 may preferably serve forms such as straight lines, circles and / or circle segments, which must be able to be detected from at least two Meßperpsychiven. If in the extruded profile 2, for example, straight segments in a corresponding
• the reference markers 31-34 are additionally introduced into a common measuring detection area, which is covered by at least two laser light-slit sensors, but can also be advantageously introduced anyway in the common measuring range.
• an outer region 4 which is drawn in FIG. 2 as a dashed line and is just detected by adjacent laser light-section sensors S1-S4 is preferably selected as the common measuring detection region.
• a shape and a thickness of the reference markers 31-34 of preferred dimensions are known.
• Reference markers 31-34 in order to shade as little as possible the inner measuring detection region where the extruded profile is to be measured, are preferably designed as thin, sheet-like strips, which are distributed uniformly in the outer region 4 as four reference markers 31-34 and directed radially inwards are arranged.
• references or reference markers are necessary in each case, which can be detected jointly by the adjacent laser light section sensors S1-S4.
• suitable as adjacent references and reference markers S1-S4 are preferably those which have a non-parallel straight line form, since the straight line shape is in each case well recognized by pattern recognition methods and can be clearly extrapolated.
• the angular position and the distance to the respective laser light-section sensor S1-S4 can be clearly determined and corrected during the calibration.
• two adjacent laser light-section sensors S1-S4 detect an additional reference mark which is as far away as possible from the remaining two reference markers, in order to reduce the influence of measuring noise or the accuracy of locating and superimposing the reference markers 31-34 to increase.
• references or reference markers 31-34 are needed in the respective common measurement coverage area, the distances of which are known and calibrated. In this way, errors from chain dimensions can be reduced.
• Reference markers 31-34 which have the shape of metal strips and are easily detectable as straight lines or straight line sections, for the determination of the
• the reference markers 31-34 are formed so that at least one of them has a coding, so that in the image data then at least such coding can be identified in order to obtain an unambiguous assignment of the reference markers in the various image data, in order in turn to be able to calibrate them correctly.
• Such coding may, for example, be provided by an additional rounding or fold on the reference marker, or the reference marker 31-34 may also have a clearly different orientation than the others.
• coarse positions of the laser light section sensors S1 -S4 can also be known for correct alignment or rotation of the raw image data or the image data in the coordinate system, so that an assignment by a calculation of smallest distances, for example by Least Mean Square
• Extruded profile 2 can be used to find the assignment of reference markers 31-34.
• the measuring device 2 shows, for example, the measuring device 1, in which all reference markers 31 - 34 can be used for the adjustment or for the calibration, for example, between laser light section sensor S1 and laser light section sensor S2. From the laser light section sensor S1, the reference markers 31 and 32 become full and the
• Reference markers 33 and 34 partly recorded. From laser light section sensor S2, the reference markers 31 and 34 are full and the reference markers 32 and 33 partly detected. It should be noted that for the superimposition of the reference markers 31 and 33 from these perspectives, the thickness of the reference markers 31, 33 is included in the calculation.
• the surface segment 24 can additionally be used as a reference between the laser light section sensors S1 and S2. For the adjustment or for the calibration between further laser light section sensors S1-S4, this approach applies analogously to the respective measuring perspectives.
• the measurement coverage area MB of the laser light section sensor S1 is shown as a dashed line and an extruded profile 2 therein different from the previously shown extruded profile with the reference markers 31-34 as detected by the laser light slicing sensor S1 represented. From the back
• Reference markers 33 and 34 are therefore only a part to be seen, since they are otherwise shadowed by the front reference markers 33 and 32.
• the reference markers 31-34 are also in the form of thin plates at the outer edge 4 of the measuring coverage area MB radially inward to the center of
• Measuring detection range MB arranged directed towards. Differently than shown and therefore it should be noted that not the entire surface of the extruded profile 2 of the laser light section sensor S1-S4 can be detected by measurement, but only parts thereof.
• the laser light section sensor S1 detects in particular the surface segments 23, 21, 22, 27A, 27B completely and 28 and 29 partly.
• all reference markers 31-34 as well as the surface segments 23 are suitable as a reference in the illustrated case, but they are relatively small. The longer a rectilinear reference or a reference marker 31-34 can be detected, the greater the accuracy by having many measurement points available for a straight line calculation.
• Reference marker 32 detected from one side 320 and continued as a straight line, which merges the straight line portion of the reference marker 34 with its side 340 and thus forms a long line with good metrological accuracy of the laser light section sensor S4, the reference markers 32 and 34 are also detected and a Straight lines formed, but from a second side 323 and 343. Taking into account the thickness of the reference markers 32 and 34, these two lines are then overlapped by the respective image data. The same applies to the reference markers 31 and 33, which are also detected by both laser light section sensors S1 and S4, formed into straight lines and overlapped in the respective image data.
• the surface segment 23 may also be referred to as
• Reference line can be used to determine the best overlap of the image data of the laser light slit sensors S1 and S4.
• the preferred method of calibration therefore detects existing lines from the image data of the respective laser light section sensor S1-S4, tries to determine them as accurately as possible by as many measuring points as possible and to identify them in comparison to the image data of the other laser light section sensors S1-S4. After identification, the matching or .. the optimal overlay of the respective image data takes place with each other.
• the respective ones are used
• Fig. 4 the same arrangement of the extruded profile 2 within a second Meßer terminates Schemes MB2 with the respective reference markers 31-34 can be seen, but from a different measuring perspective of the laser light section sensor S4. It can be seen that the extruded profile 2 is supplemented by the measurement perspective of the laser light section sensor S4, for example, the image data of the surface segments 24, 23, partially 26, 26 B and 26C in addition to the image data from the measurement perspective by laser light section sensor S1
• the reference marker 33 is detected by the side 330, the reference marker 32 by the side 323, the reference marker 34 partially by the side 343, and the reference marker 31 partly by the side 30.
• the corresponding transformation matrix for this laser light section sensor S4 is determined from the image data measured thereby in such a way that the positions and
• FIG. 5 also shows a measuring perspective of the extruded profile 2 from an additional view of a laser light-section sensor rotated by 45 degrees to the right. It becomes clear that the surface segment 23 of the extruded profile 2 can be detected better or more accurately by measuring technology, especially regarding its corners.
• the thin dotted lines indicate ray trajectories of the laser light-section sensor turned to the right. Either one or more additional laser Lichtsacrificingensoren be used or it may already be in the
• Measuring device 1 laser light section sensors used in total S1-S4 for a time instant of the measurement and moved back,
• the rotational travel position of the laser light section sensors S1-S4 can be from the arrangement as well as in the calibration using the reference marker 31-34 and reference determine references in the extruded profile, so that the measurement and image data of the extruded profile 2 (as well as the reference marker 3 -34) from the respective
• references and the reference markers 31-34 need not have any known, defined distances from each other and thus no known positions; they only have to be located in the common measuring detection ranges of the laser light-section sensors S1-S4.
• the number of laser light section sensors S1 to S4 to be mutually coordinated with one another is arbitrary as long as the above-described condition of the common detection of the references and / or the reference markers 31-34 is fulfilled. It should also be clarified once again that even reference markers 31-34 may not be necessary for the calibration if sufficient references are present in the extruded profile 2 which satisfy the condition that at least two references are shared by adjacent laser light slit sensors S1-S4 be recorded; this is for example
• References and the reference markers 31-34 is arbitrary, as long as the condition that at least two references or at least two reference markers 31-34 or at least one reference and a reference marker 31-34 are jointly detected by adjacent laser light-slit sensors S1-S4 is met
• Reference marker 31-34 is equal, that then their individual positions in the individual image data of the respective laser light section sensors S1 -S4 must be roughly known in order to make a clear assignment of the reference marker 31 -34 in the respective image data can. In any case, it must not come to a confusion of the reference marker 31-34. Otherwise, at least one of the
• Reference marker 31-34 which is visible in adjacent scans, encodes for bear clear identification in the image data of the adjacent scans and / or the extruded profile itself are used for the assignment,
• the laser light-slit sensors S1-S4 can be both 2D and 3D sensors.
• the laser light-slit sensors S1-S4 can be both 2D and 3D sensors.
• the calibration comprises a correction determination of the offsets in the X and Y directions and of the rotation angle, so that the image data of adjacent laser light section sensors S1-S4 are optimally imaged in a common coordinate system on the basis of known or common references, such as reference lines ,
• a transformation matrix for the respective laser light section sensor S1-S4 is calculated and then applied to the respective image data (for correction).
• Reference markers 31-34 are available with defined, known distances, the calibration can also include the correction of the scaling. It should be noted that a preferred method of calibrating the scaling also includes an optimal averaging between the image data of the different light section sensors S1-S4, to which preferably the least mean square method is used.
• Extruded profile 2 is available for all types of test specimens to be measured, which may for example also be longitudinally variable profiles, tubes or objects that are located in the measuring device 1 or passed through the measuring device 1 therethrough.
• Image data substantially relates to calibrated image data obtained from the raw image data by using a transformation matrix.
• the raw image data can already be pre-calibrated data that has been calibrated relative to the respective laser light section sensor S1-S4 and / or to the measuring device 1.
• the reference markers 31-34 are not constantly in the measuring device 1, but are only temporarily introduced into the measuring device 1 for the time of calibration.
• the individual laser light section sensors S1-S4 comprise differently colored lasers in order to be able to measure at the same time. Otherwise, measurements are carried out sequentially, so that there is no mutual interference
• Measurement results takes place In a sequential measurement, it is preferred to measure each time simultaneously with adjacent laser light-section sensors S1-S4, in order thereby also to detect the offset of their laser lines relative to one another in the feed direction Z.
• the unambiguous assignment of the reference markers 31-34 in the raw image data happens so that the positions of the respective laser light section sensors S1 -S4 are substantially known and the detected and recognized reference markers 31-34 are in a certain local area with a certain fuzziness.
• one of the detected reference markers 31-34 can then lie at a defined position in the common coordinate system +/- 2 cm.
• the measuring device (1) along the extruded profile (2) is moved, wherein it depends on the relative movement between the measuring device (1) and the extruded profile (2). Further possible embodiments are described in the following claims.

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

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• 2011
  • 2011-01-25 DE DE102011000304.5A patent/DE102011000304B4/de active Active
• 2012
  • 2012-01-25 CN CN201280006448.3A patent/CN103328923B/zh active Active
  • 2012-01-25 CA CA2825250A patent/CA2825250C/en active Active
  • 2012-01-25 EP EP12705627.3A patent/EP2668468A1/de not_active Withdrawn
  • 2012-01-25 US US13/981,718 patent/US9127936B2/en not_active Expired - Fee Related
  • 2012-01-25 WO PCT/EP2012/051129 patent/WO2012101166A1/de active Application Filing

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