WO2019082528A1 - Procédé de mesure, programme informatique et système de mesure - Google Patents

Procédé de mesure, programme informatique et système de mesure

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Publication number
WO2019082528A1
WO2019082528A1 PCT/JP2018/033450 JP2018033450W WO2019082528A1 WO 2019082528 A1 WO2019082528 A1 WO 2019082528A1 JP 2018033450 W JP2018033450 W JP 2018033450W WO 2019082528 A1 WO2019082528 A1 WO 2019082528A1
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WIPO (PCT)
Prior art keywords
displacement
measurement
oblique
deformation
analysis
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PCT/JP2018/033450
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English (en)
Japanese (ja)
Inventor
志遠 李
慶華 王
浩 津田
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国立研究開発法人産業技術総合研究所
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Application filed by 国立研究開発法人産業技術総合研究所 filed Critical 国立研究開発法人産業技術総合研究所
Priority to JP2019549917A priority Critical patent/JP6982336B2/ja
Publication of WO2019082528A1 publication Critical patent/WO2019082528A1/fr

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    • 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

Definitions

  • the present disclosure relates to a technique for measuring displacement or vibration of a measurement area.
  • the purpose of the measurement method, computer program and measurement system is to make it possible to measure displacement or vibration of the measurement area more appropriately.
  • a measurement method is a measurement method in a measurement system including an imaging device and an information processing device, and the imaging device includes a longitudinal direction of a rectangular measurement area which is a part of a sample, and a rectangular shape
  • the imaging device includes a longitudinal direction of a rectangular measurement area which is a part of a sample, and a rectangular shape
  • the image before and after the deformation of the measurement area to which the oblique lattice is attached so as to match the longitudinal direction of the oblique lattice is photographed, and the information processing apparatus measures the longitudinal lattice by the moire analysis from the images before and after the deformation. Calculating the phase difference in the direction, and calculating the displacement or vibration in the short direction before and after the deformation of the measurement region based on the calculated phase difference in the longitudinal direction.
  • a measurement method is a measurement method in a measurement system having an imaging device and an information processing device, and the imaging device is a rectangular measurement area which is a part of a sample, and is rectangular
  • the image before and after deformation of the measurement area to which the two diagonal grids are attached is taken so that the stretching directions of the lines in the two diagonal grids are different from each other, and the information processing apparatus Calculating the phase difference in the longitudinal direction of each of the two oblique gratings by analysis, and calculating the two-dimensional in-plane displacement or vibration before and after deformation of the measurement region based on the calculated phase difference in the longitudinal direction Including.
  • the computer program is a computer program of an information processing apparatus included in a measurement system including an imaging device, and is a longitudinal direction of a rectangular measurement area which is a part of a sample, captured by the imaging device And the longitudinal direction of the oblique grating calculated from the images before and after the deformation of the measurement area to which the oblique grating is attached so that the longitudinal direction of the rectangular oblique grating matches the longitudinal direction of the oblique grating.
  • the information processing apparatus is caused to calculate displacement or vibration in the lateral direction before and after deformation of the measurement region based on the phase difference in the direction.
  • a computer program is a computer program of an information processing apparatus included in a measurement system including an imaging device, and is a rectangular measurement area which is a part of a sample and is captured by the imaging device. From the images before and after the deformation of the measurement area in which the two diagonal grids are pasted so that the stretching directions of the lines in the two rectangular grids are different from each other, according to Moire analysis, the respective lengths of the two diagonal grids The information processing apparatus is caused to calculate the phase difference in the direction and to calculate the two-dimensional in-plane displacement or vibration before and after the deformation of the measurement region based on the calculated phase difference in the longitudinal direction.
  • a measurement system is a measurement system including an imaging device and an information processing device, and the imaging device includes a longitudinal direction of a rectangular measurement area which is a part of a sample, and a rectangular oblique grid The image before and after deformation of the measurement area to which the oblique grid is attached so as to match the longitudinal direction of the image is taken, and the information processing apparatus determines the position of the oblique grid in the longitudinal direction A first calculation unit that calculates a phase difference and a second calculation unit that calculates displacement or vibration in the short direction before and after deformation of the measurement region based on the calculated phase difference in the longitudinal direction.
  • a measurement system is a measurement system including an imaging device and an information processing device, and the imaging device is a rectangular measurement area which is a part of a sample, and two rectangular shapes.
  • the image before and after deformation of the measurement area to which two diagonal grids are attached is photographed so that the extension directions of the lines in the diagonal grid are different from each other, and the information processing apparatus analyzes the photographed image before and after deformation by moire analysis.
  • a two-dimensional in-plane displacement or vibration before and after deformation of the measurement area is calculated based on the first calculation unit that calculates the longitudinal phase difference of each of the two oblique gratings and the calculated longitudinal phase difference. And a second calculation unit.
  • the measurement method, the computer program, and the measurement system can measure displacement or vibration of the measurement area more appropriately.
  • FIG. 1 is a diagram showing an example of a schematic configuration of a measurement system 100. It is a flowchart which shows the example of operation
  • the present embodiment is a technique for measuring in-plane and out-of-plane displacements and vibrations of an object from a regular pattern that is arranged in an oblique direction on the object and has repetitions, which is captured by an optical camera having an imaging device. About.
  • an image before and after deformation of a regularly repeated pattern (for example, a grid pattern) on an object captured by an optical camera provided with an imaging device is analyzed.
  • a one-dimensional linear grid marker or a two-dimensional dot grid marker as shown in FIGS. 1A to 1D is used.
  • the displacement amount of the vertical grid (FIG. 1A) is measured and analyzed for horizontal displacement measurement, and the horizontal grid (FIG. 1B) for vertical displacement measurement. The amount of displacement is measured and analyzed.
  • the grid including both horizontal and vertical grids is rectangular (FIG. 1C) or square It is necessary to have the mesh shape (FIG. 1D) or the two-dimensional dot pattern (the mesh inverted shape).
  • the marker needs to have a width and height at least twice the grating pitch. Therefore, when performing mechanical tests of nano / micro structures or measurement of displacement on a road surface such as a bridge, the installation place of the marker is limited. In addition, it is difficult to install the marker on a pillar-shaped structure such as a utility pole, a street lamp, or a space structure, which is a curved object.
  • diagonal grids are used instead of horizontal grids, vertical grids or orthogonal grids being arranged parallel to either the horizontal or vertical direction as commonly used.
  • the horizontal grid is a grid in which a plurality of lines (parallel lines) extending in the horizontal direction of space coordinates are arranged at regular intervals.
  • the vertical grid is a grid in which each of a plurality of lines extending in the direction perpendicular to spatial coordinates is arranged at regular intervals.
  • the orthogonal grid is a grid in which each of a plurality of lines extending in the horizontal direction is arranged at regular intervals, and a plurality of lines extending in the vertical direction is arranged at regular intervals.
  • the lattice direction means a direction orthogonal to the direction in which the regular change of the lattice appears.
  • An oblique lattice is a lattice in which the lattice direction is oblique to the horizontal or vertical direction. That is, in the diagonal grid, a plurality of lines extending obliquely with respect to the longitudinal direction or the short direction of the diagonal grid are arranged at regular intervals.
  • the oblique grid may be provided by inclining the horizontal grid or the vertical grid with respect to the horizontal direction or the vertical direction in the rectangular measurement area.
  • the oblique lattice may be provided by inclining the horizontal lattice with respect to the short direction of the oblique lattice.
  • moiré fringes are regarded as a lattice, and two-stage moiré fringes are further calculated from the calculated moiré fringes by appropriate thinning processing and luminance interpolation processing, and wide-field, high-sensitive deformation measurement is performed Be done.
  • FIG. 2 is a diagram showing an example of a schematic configuration of the measurement system 100 according to the embodiment.
  • the measurement system 100 includes a sample 200, an imaging device 300, and an information processing device 400.
  • the sample 200 is, for example, a columnar structure such as a utility pole, a street lamp, a space structure (rocket or the like), or the like.
  • the sample 200 includes a rectangular measurement area 201 which is a part of the sample 200.
  • the measurement area 201 may have at least one pixel in each side at least when imaged by the imaging device 300, and may be, for example, linear (horizontal or vertical linear).
  • a rectangular oblique grid 202 is attached to the measurement area 201.
  • a plurality of lines extending obliquely with respect to the longitudinal direction or the short direction of the oblique grating 202 are arranged at regular intervals.
  • the oblique grid 202 is formed as a tape to which glue or the like is attached on the back surface, and is affixed by the measurer to the measurement area 201 so that the longitudinal direction of the measurement area 201 and the longitudinal direction of the oblique grid 202 coincide.
  • the imaging device 300 is, for example, an optical camera.
  • the imaging device 300 is output from an imaging device such as a charge coupled device (CCD) device or a complementary metal oxide semiconductor (C-MOS) device, an imaging optical system for forming an image on the imaging device, and an imaging device. And an A / D converter for amplifying and converting the electrical signal to analog / digital conversion.
  • the imaging device 300 is fixedly installed so as to periodically image the measurement area 201 of the sample 200.
  • the imaging device 300 captures an image before and after the deformation of the measurement area 201 when the measurement area 201 to which the oblique lattice 202 is attached is deformed.
  • the imaging device 300 is connected to the information processing device 400, converts the captured image into a digital image having each pixel having a luminance value in the range of 0 to 255 (in the case of an 8-bit image sensor), and outputs it to the information processing device 400 Do.
  • the information processing apparatus 400 is, for example, a personal computer.
  • the information processing device 400 includes an interface device 401, a communication device 402, an input device 403, a display device 404, a storage device 405, and a central processing unit (CPU) 410.
  • CPU central processing unit
  • the interface device 401 has an interface circuit conforming to a serial bus such as USB (Universal Serial Bus), and is electrically connected to the imaging device 300 to transmit and receive image data and various information.
  • a serial bus such as USB (Universal Serial Bus)
  • the communication device 402 has a wired communication interface circuit such as Transmission Control Protocol / Internet Protocol (TCP / IP), and communicates with an external device in accordance with a communication method such as Ethernet (registered trademark).
  • TCP / IP Transmission Control Protocol / Internet Protocol
  • the communication apparatus 402 may communicate with an external apparatus via an access point (not shown) according to a wireless local area network (LAN) communication scheme.
  • LAN wireless local area network
  • the input device 403 includes an input device such as a touch panel type input device, an input device such as a keyboard and a mouse, and an interface circuit which obtains a signal from the input device.
  • the input device 403 receives input data input by the measurer, and outputs a signal corresponding to the received input data to the CPU 410.
  • the display device 404 includes a display configured of liquid crystal, organic EL (Electro-Luminescence), and the like, and an interface circuit that outputs image data or various types of information to the display.
  • the display device 404 is connected to the CPU 410 and displays the image data output from the CPU 410 on the display.
  • the storage device 405 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk.
  • the storage device 405 stores a computer program, a database, a table, and the like used for various processes of the information processing apparatus 400.
  • the computer program may be installed from a computer-readable portable recording medium such as, for example, a compact disk read only memory (CD-ROM) or a digital versatile disk read only memory (DVD-ROM).
  • the computer program is installed in the storage device 405 using a known setup program or the like.
  • the pitch of the oblique grating 202 (the interval between adjacent lines), the angle of each line, the resolution of the image captured by the imaging device 300, the frame rate, and the imaging device 300
  • the number of pixels between adjacent lines of the diagonal grid 202 in the resulting image is stored.
  • the CPU 410 operates based on a program stored in advance in the storage device 405.
  • the CPU 410 may be a general purpose processor. Note that even if a graphics processing unit (GPU), a digital signal processor (DSP), a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc. are used instead of the CPU 410. Good.
  • GPU graphics processing unit
  • DSP digital signal processor
  • LSI large scale integration
  • ASIC application specific integrated circuit
  • FPGA field-programmable gate array
  • the CPU 410 is connected to the interface device 401, the communication device 402, the input device 403, the display device 404, and the storage device 405, and controls these units.
  • the CPU 410 reads each program stored in the storage device 405 and operates according to each read program.
  • the CPU 410 functions as an acquisition unit 411, a first calculation unit 412, and a second calculation unit 413.
  • FIG. 3 is a flowchart showing an example of operation of measurement processing by the imaging device 300 and the information processing device 400.
  • the information processing apparatus 400 measures the displacement or vibration in the longitudinal direction.
  • the information processing apparatus 400 is, for example, a horizontal displacement with respect to a sample in which it is difficult to attach a grid whose grid direction is vertical, such as a pillar structure such as a street lamp, a utility pole, or a space structure. It becomes possible to analyze the vibration.
  • the grid direction is horizontal, as in a structure such as a road surface where it is necessary to measure the displacement of the central portion using a flat marker having a sufficiently low height. It becomes possible to analyze the vertical displacement or vibration on a sample where it is difficult to attach a grid.
  • the information processing apparatus 400 performs longitudinal displacement (vertical direction) displacement or the size of the grating 202 sufficiently large by moire analysis. Analyze the vibration.
  • the information processing apparatus 400 calculates a horizontal displacement or vibration in which the size of the grid 202 is small by performing a numerical correction operation on the calculated displacement value (displacement value). As a result, the information processing apparatus 400 can correctly measure displacement or vibration using a diagonal grid.
  • the horizontal direction and the vertical direction do not have to coincide with the vertical and horizontal alignment directions of the imaging elements of the imaging device 300, but in order to simplify the process, it is desirable to coincide. If the horizontal and vertical directions do not coincide with the vertical and horizontal alignment directions of the imaging elements of the imaging device 300, the level of the imaging device 300 or a level separately provided from the imaging device 300, etc. Thus, the deviation angle is measured. Then, the information processing apparatus 400 corrects the captured image using the measured deviation angle.
  • the imaging device 300 captures an image before and after deformation of the measurement area 201 to which the oblique lattice 202 is attached (step S101).
  • the acquisition unit 411 of the information processing device 400 acquires an image before and after deformation of the measurement area 201 from the imaging device 300 via the interface device 401 (step S102).
  • the first calculation unit 412 calculates the phase difference in the longitudinal direction of the oblique grating 202 by moire method analysis from the acquired images before and after deformation (step S103). For example, the first calculator 412 calculates the phase difference in the longitudinal direction of the oblique grating 202 by a one-dimensional sampling moire method.
  • the change in the phase of the moiré fringes before and after the deformation of the measurement area 201 when the one-dimensional sampling moiré method is applied will be described using the oblique lattice shown in FIG. 4A.
  • the x-direction and y-direction pitches of the grating 202 are Px and Py, respectively
  • the luminance I of the grating 202 in the image before deformation is expressed by Equation (1).
  • x and y are horizontal and vertical positions (coordinates) in the image before deformation, respectively, and A and B are modulation amplitude and background luminance of the grating 202, respectively.
  • the angle in the cos function of equation (1) represents the phase ⁇ of the grating 202. That is, the phase ⁇ is expressed by equation (2).
  • the phase ⁇ ′ of the grating 202 corresponding to the luminance I in the image after deformation is expressed by Equation (3).
  • the deformation is a simple rigid body displacement.
  • the amount of strain due to deformation is small enough to be negligible.
  • Equation (4) the phase change (phase difference) ⁇ of the grating 202 caused by the deformation of the sample 200 (measurement region 201) is expressed by Equation (4).
  • the one-dimensional sampling moiré method is applied to reduce the number of moiré stripes before and after deformation obtained by downsampling at the thinning number T x in the x direction.
  • the phase ⁇ mx and the phase ⁇ ′ mx are expressed by Equations (5) and (6), respectively.
  • Equation (7) the phase difference ⁇ mx of Moire fringes generated by the deformation of the sample 200 (measurement region 201) obtained by analysis in the x direction is expressed by Equation (7).
  • one-dimensional sampling moire method is applied to the phase ⁇ of the equation (2) and the phase ⁇ ′ of the equation (3) to obtain moiré before and after deformation obtained by downsampling with the thinning number T y in the y direction.
  • the phase ⁇ my and the phase ⁇ my ′ of the fringes are expressed by Equations (8) and (9), respectively.
  • Equation 10 the phase difference ⁇ mx of Moire fringes generated by the deformation of the sample 200 (measurement region 201) obtained by analysis in the y direction is expressed by Equation (10).
  • the phase difference of the grating 202 which is the displacement of the sample 200 (measurement region 201), is analyzed in the x direction and in the y direction. And the result will be the same. That is, the phase difference ⁇ of the grating 202 is expressed by equation (11).
  • the information processing apparatus 400 can calculate the displacement in the horizontal direction by analyzing the oblique lattice 202 in the vertical direction. Similarly, the information processing apparatus 400 can calculate the displacement in the vertical direction by analyzing the diagonal grid 202 in the horizontal direction.
  • the second calculator 413 calculates displacement or vibration in the lateral direction before and after deformation of the measurement region 201 based on the phase difference in the longitudinal direction calculated by the first calculator 412 (step S104).
  • xy coordinates are defined with the horizontal direction as the x axis and the vertical direction as the y axis. Let the displacement in the horizontal or x direction be u x, and let the displacement in the vertical or y direction be u y .
  • a coordinate system on analysis by the one-dimensional sampling moiré method is defined. As shown in FIG. 5B, XY coordinates are defined. The horizontal direction in the analysis by the one-dimensional sampling moire method is taken as the X coordinate, and the vertical direction in the analysis by the one-dimensional sampling moire method is taken as the Y coordinate.
  • the xy coordinates and the XY coordinates coincide.
  • the displacement in the X direction is calculated by analyzing in the X direction (horizontal direction).
  • the displacement in the Y direction is calculated by analyzing in the Y direction (vertical direction).
  • each line in the oblique lattice 202 is arranged to be inclined at an angle ⁇ (counterclockwise as positive) with respect to the x axis in the xy coordinate system.
  • ⁇ counterclockwise as positive
  • the X axis and the Y axis in the XY coordinate system are arranged to be inclined by an angle - ⁇ with respect to the x axis and the y axis in the xy coordinate system, respectively.
  • the angle ⁇ between the x-axis and y-axis and the X-axis and Y-axis is ⁇ 90 ° ⁇ ⁇ 90 °.
  • each line of the oblique grid 202 is analyzed in parallel with the Y axis, and therefore, the x axis and y axis and the X axis and Y axis
  • the angle ⁇ is expressed by equation (12). Therefore, when displacement analysis is performed in the X direction, the lattice angle ⁇ is 0 ° ⁇ ⁇ 180 °.
  • each line of the oblique grid 202 is analyzed in a state parallel to the X axis, so the x axis and y axis and the X axis and Y axis
  • the angle ⁇ is expressed by equation (13). Therefore, when displacement analysis is performed in the Y direction, the lattice angle ⁇ is ⁇ 90 ° ⁇ ⁇ 90 °.
  • the displacement vector u is represented by the sum of a displacement vector u x in the x direction and a displacement vector u y in the y direction. Ru. That is, the displacement vector u is expressed by equation (14).
  • the vector u X having the analysis value u X is decomposed into a vector u Xx for the displacement u x in the x direction and a vector u Xy for the displacement u y in the y direction. That is, the vector u X is expressed by equation (15).
  • the analysis value u Xx with respect to the displacement amount u x in the x direction and the analysis value u Xy with respect to the displacement amount u y in the y direction are expressed by Equations (16) and (17), respectively. .
  • Equation (16) the analysis value u X is expressed by Equation (18) using the displacement u x in the x direction and the displacement u y in the y direction.
  • the displacement amount u x in the x direction is calculated from the analysis value u X of the oblique grid.
  • the displacement amount u y in the y direction is calculated from the analysis value u X of the oblique grid.
  • the information processing apparatus 400 analyzes the u X in the X direction by the one-dimensional sampling moire method to obtain the x direction or the x direction.
  • the displacement in the y direction can be calculated.
  • u X is divided by ( ⁇ 2 ⁇ ) by multiplying the grating pitch P (FIG. 4A) by the phase difference of the moire fringes in the X direction on the same principle as displacement measurement of the conventional one-dimensional sampling moire method.
  • the displacement vector u of the oblique lattice 202 can be expressed in an XY coordinate system.
  • an analysis value u Y is calculated.
  • the vector u Y having the analysis value u Y is decomposed into a vector u Yx for the displacement u x in the x direction and a vector u Yy for the displacement u y in the y direction. Equations (21) to (24) hold true for the vector u Y in the same manner as when displacement analysis is performed in the X direction.
  • the displacement amount u x in the x direction is calculated from the analysis value u Y of the oblique grid.
  • the displacement amount u y in the y direction is calculated from the analysis value u Y of the oblique grid.
  • the information processing apparatus 400 analyzes the u Y in the Y direction by the one-dimensional sampling moire method to obtain the x direction or the x direction.
  • the displacement in the y direction can be calculated.
  • u Y is based on the same principle as displacement measurement in the conventional one-dimensional sampling moire method, by multiplying the phase difference of the moire fringes in the Y direction by the grating pitch P (FIG. 4A) and dividing by ( ⁇ 2 ⁇ ) It is calculated.
  • the second calculation unit 413 performs frequency conversion on a waveform in which displacements calculated for each acquired image are arranged in time series, using fast Fourier transform (FFT).
  • FFT fast Fourier transform
  • the second calculation unit 413 detects peak frequencies in one or a plurality of predetermined frequency bands from the waveform subjected to frequency conversion, and detects each detected peak frequency in the lateral direction before or after deformation of the measurement area 201 or Calculated as vibration (number) in the longitudinal direction.
  • the first calculation unit 412 may calculate the phase difference in the longitudinal direction of the oblique grating 202 using the two-dimensional sampling moire method instead of the one-dimensional sampling moire method as the moire method analysis.
  • the method of calculating the phase of the moiré fringes by the two-dimensional sampling moiré method see, for example, Japanese Patent No. 5818218.
  • the phase difference of the moire fringes calculated by the two-dimensional sampling moire method is equivalent to the phase difference calculated by the one-dimensional sampling moire method shown in the equation (4). That is, the analysis result by the two-dimensional sampling moire method and the analysis result by the one-dimensional sampling moire method are the same.
  • the two-dimensional sampling moire method requires a longer measurement time as compared to the one-dimensional sampling moire, it is suitable for displacement analysis using a noisy image because it is resistant to random noise of the camera.
  • the two-dimensional sampling moire method as in the one-dimensional sampling moire method, it is possible to use the phase difference of the grating generated by the deformation of the object for the displacement measurement of the oblique grating.
  • the displacement and vibration in each direction are calculated from the phase difference ⁇ mxy of the moiré fringes before and after deformation in the same manner as in the case of using the one-dimensional sampling moiré method.
  • the first calculation unit 412 may calculate the phase difference in the longitudinal direction of the oblique grating 202 by using the two-stage moire method instead of the one-dimensional sampling moire method as the moire method analysis.
  • the method of calculating the phase of the moiré fringes by the two-stage moiré method see, for example, International Publication WO2018 / 061321.
  • the x direction is first obtained as in the one-dimensional sampling moire method.
  • downsampled by decimation number T x close to P x is a grating pitch moiré fringes is calculated.
  • the calculated moire fringes are regarded as a lattice, and downsampling is performed again at a thinning number T x (2) close to the pitch of the lattice to calculate a two-stage moire fringe.
  • the phase ⁇ mx (2) of this two-stage moire fringe is expressed by equation (31).
  • the phase difference of the moire fringes calculated by applying the two-step moire method to the x direction of the oblique grating is equivalent to the phase difference calculated by the one-dimensional sampling moire method shown in equation (4).
  • the analysis result by the two-stage moire method is the same as the analysis result by the one-dimensional sampling moire method.
  • the spatial resolution is lowered as compared with the one-dimensional sampling moire method, but it becomes possible to measure the displacement with a wide field of view and high accuracy.
  • phase difference of the moire fringes calculated by applying the two-stage moire method to the y direction of the oblique grating is equivalent to the phase difference calculated by the one-dimensional sampling moire method shown in equation (4).
  • the analysis result by the two-stage moire method and the analysis result by the one-dimensional sampling moire method are the same.
  • the two-stage moire method as in the one-dimensional sampling moire method, it is possible to use the phase difference of the grating caused by the deformation of the object for the displacement measurement of the oblique grating.
  • the displacement and vibration in each direction are calculated from the phase difference ⁇ mx (2) or ⁇ my (2) of the moiré fringes before and after deformation in the same manner as in the case of using the one-dimensional sampling moiré method.
  • the phase difference of the grating caused by the deformation of the object is oblique. It can be used to measure grid displacement.
  • the displacement can be calculated by using a single diagonal grid.
  • the information processing apparatus 400 calculates two variables of u x and u y. There is a need. In this case, the information processing apparatus 400 can not calculate the displacement only by using a single diagonal grid.
  • two rectangular oblique lattices 202 are attached to the measurement area 201 of the sample 200. It is also good.
  • a diagonal mesh grid may be attached in the measurement area 201 of the sample 200 in which two diagonal grids are overlapped. In this case, two different diagonal grids are extracted in advance by image processing such as Fourier transform and low-pass filter processing.
  • each of the two oblique gratings 202 a plurality of lines extending obliquely with respect to the longitudinal direction or the short direction of the oblique grating 202 are arranged at regular intervals.
  • Each of the two diagonal grids 202 is formed as a tape with glue or the like attached to the back surface, and the measure direction 201 is such that the stretching directions of the lines in the two diagonal grids 202 are different (alternately) by the measurer. It is pasted.
  • the two oblique grids 202 are attached to the rectangular measurement area 201 of the sample 200 so that the longitudinal direction of the measurement area 201 and the longitudinal direction of the oblique grids 202 coincide with each other.
  • the displacement amounts of the two diagonal grids 202 are assumed to be the same. That is, in the two diagonal grids 202, each line is assumed to change similarly (rigid body displacement).
  • the two diagonal grids 202 may be separately formed as two marker or sheet grids, or may be integrally formed as one marker or sheet grid.
  • the information processing apparatus 400 calculates displacement in any direction in the two oblique grids 202 by regarding each of the points Q 1 and Q 2 on the two oblique grids 202 as one point.
  • the information processing apparatus 400 analyzes displacement in a direction different from the direction in which the displacement is measured (performs displacement analysis in the vertical direction for displacement measurement in the horizontal direction). Thereby, the information processing apparatus 400 can measure the displacement in the horizontal direction or the vertical direction individually. Alternatively, the information processing apparatus 400 can measure the horizontal and vertical displacements simultaneously.
  • step S101 the imaging device 300 captures an image before and after deformation of the measurement area 201 to which the two oblique grids 202 are attached.
  • step S102 the acquisition unit 411 acquires images before and after deformation of the measurement area 201 from the imaging device 300.
  • the first calculating unit 412 performs the phase difference in the longitudinal direction of the two oblique gratings 202 by moire analysis from the acquired images before and after the deformation, as in the case of using the single oblique grating 202.
  • the first calculator 412 calculates the phase difference in the longitudinal direction of each oblique grating 202 by a one-dimensional sampling moire method.
  • the first calculator 412 may calculate the phase difference in the longitudinal direction of each oblique grating 202 by the two-dimensional sampling moire method.
  • the first calculation unit 412 may calculate the phase difference in the longitudinal direction of each oblique grating 202 by the two-stage moire method.
  • step S104 the second calculating unit 413 deforms the measurement area 201 based on the phase difference in the longitudinal direction calculated by the first calculating unit 412, as in the case of using the single oblique grating 202.
  • the front and back two-dimensional in-plane displacement or vibration is calculated.
  • ⁇ 1 and ⁇ 2 are 0 ° ⁇ 1 ⁇ 180 ° and 0 ° ⁇ 2 ⁇ 180 °, respectively, and displacement analysis is performed in the Y direction.
  • u X1 is calculated as the displacement amount of point Q 1 on diagonal grid 1 when displacement analysis is performed in the X direction by the one-dimensional sampling moire method.
  • u X2 is calculated as the amount of displacement of the point Q 2 on the diagonal grid 2.
  • u X1 and u X2 are represented by Formula (38) and Formula (39), respectively, by Formula (18).
  • K 1 and K 2 are represented by Formula (42) and Formula (43), respectively.
  • each of the displacement in the x direction and the y direction is calculated by analyzing in the X direction by the one-dimensional sampling moire method.
  • u Y1 is calculated as the displacement amount of point Q 1 on diagonal grid 1 when displacement analysis is performed in the Y direction by one-dimensional sampling moire method.
  • u Y2 is calculated as the amount of displacement of the point Q 2 on the diagonal grid 2.
  • u Y1 and u Y2 are represented by Formula (44) and Formula (45), respectively, by Formula (24).
  • K 1 and K 2 are represented by the above-mentioned formula (42) and formula (43), respectively.
  • each of the displacement in the x direction and the y direction is calculated by analyzing in the Y direction by the one-dimensional sampling moire method.
  • FIG. 11 shows the setup of the laboratory experiment.
  • a diagonal grid 6 is used in which the grid pitch is 4 mm and each line has various angles.
  • the grating angles are 45 °, 60 °, -45 ° (135 °), -60 ° (120 °).
  • the grid 6 is photographed by the digital camera 5 while being displaced by 0.1 mm in the range of 0 to 1 mm in the horizontal direction (x direction) 8 by the moving stage 7.
  • the camera 5 is installed so that the lattice pitch on the photographed image is 10 pixels.
  • a continuous frame (still image) in the captured moving image is subjected to displacement analysis by a one-dimensional sampling moire method as an image before and after deformation.
  • the displacement analysis of the photographed image is performed for each of the X direction and the Y direction.
  • FIG. 12A shows a graph of the amount of displacement in the case of displacement analysis in the X direction by the one-dimensional sampling Moire method using grating patterns 6 having grating angles of 45 ° and 60 °.
  • FIG. 12B shows a graph of the displacement amount corrected by Expression (19) by applying the method of the present embodiment.
  • the horizontal axis indicates the given displacement
  • the vertical axis indicates the displacement calculated as a result of the displacement analysis.
  • FIG. 12C shows a graph of the displacement amount when displacement analysis is performed in the Y direction by the one-dimensional sampling moire method.
  • FIG. 12D shows a graph of the amount of displacement calculated by equation (25) by applying the method of the present embodiment. Even when the displacement analysis was performed in the Y direction by the one-dimensional sampling moire method, it was confirmed that the displacement amount was accurately calculated as in the case where the displacement analysis was performed in the X direction by the one-dimensional sampling moire method.
  • Measurement example 2 (Displacement measurement with a single diagonal grid when displaced only in the vertical direction) The results of laboratory experiments of displacement measurement when the grid is displaced in the vertical direction (y direction) under the same conditions and procedures as in Measurement Example 1 are shown below.
  • the grid 6 is photographed by the digital camera 5 while being displaced by 0.1 mm in the range of 0 to 1 mm in the vertical direction by the moving stage 7.
  • FIG. 13A shows a graph of the amount of displacement in the case of displacement analysis in the X direction by the one-dimensional sampling moire method using grating patterns 6 having grating angles of 45 ° and 60 °.
  • FIG. 13B shows the value of the amount of displacement calculated by equation (20) by applying the method of the present embodiment.
  • the horizontal axis indicates the given displacement
  • the vertical axis indicates the displacement calculated as a result of the displacement analysis.
  • FIG. 13C shows a graph of the displacement amount when displacement analysis is performed in the Y direction by the one-dimensional sampling moire method.
  • FIG. 13D shows a graph of the displacement amount corrected by Expression (26) by applying the method of the present embodiment. Even when the displacement analysis was performed in the Y direction by the one-dimensional sampling moire method, it was confirmed that the displacement amount was accurately calculated as in the case where the displacement analysis was performed in the X direction by the one-dimensional sampling moire method.
  • the setup shown in FIG. 11 is used.
  • the diagonal grating pair 6 is displaced by 0.1 mm in the range of 0 to 1 mm in the horizontal direction (x direction) as the displacement in the arbitrary direction 10 by the moving stage 7 and in the vertical direction (y
  • the moving image is captured by the digital camera 5 while being displaced by 0.2 mm in the range of 0 to 2 mm in the direction.
  • FIG. 15A shows a graph of the amount of displacement when displacement analysis is performed in the X direction by the one-dimensional sampling moire method.
  • FIG. 15C shows a graph of the amount of displacement calculated by equations (40) to (43) by applying the method of the present embodiment.
  • the horizontal axis represents the given displacement
  • the vertical axis represents the displacement calculated as a result of the displacement analysis.
  • the horizontal axis indicates the displacement amount u x in the x direction calculated as a result of displacement analysis
  • the vertical axis indicates the displacement amount u y in the y direction calculated as a result of displacement analysis.
  • FIG. 15C it was confirmed that the displacement amount was accurately calculated at any grid angle.
  • FIG. 15B shows a graph of the displacement amount when displacement analysis is performed in the Y direction by the one-dimensional sampling moire method.
  • FIG. 15D shows a graph of the amount of displacement calculated by Expression (46) to Expression (47) and Expression (42) to Expression (43) by applying the method of the present embodiment. Even when displacement analysis was performed in the Y direction by the one-dimensional sampling moire method, it was confirmed that the displacement amount was accurately calculated.
  • the displacement in the x direction and the displacement in the y direction can be properly separated and accurately measured even when displacement analysis is performed in either the X or Y direction by one-dimensional sampling moire method That was confirmed.
  • FIG. 16 shows the grid marker settings for this experiment.
  • the pitch of the grid 11 of the conventional method is set to 40 mm
  • the pitch of the grid 12 of the present embodiment is set to 10 mm.
  • the displacement of the bridge when the truck passes over the bridge was measured by the conventional method and the method of the present embodiment, and the measurement results of the displacement were compared and verified.
  • FIG. 17A shows the measurement result of displacement by the conventional method
  • FIG. 17B shows the measurement result of displacement by the method of the present embodiment. From the measurement results of the displacement, it is confirmed that the displacement is measured in the method of the present embodiment as well as the conventional method.
  • FIG. 18 shows the setup of this measurement.
  • a lattice marker 14 according to the method of the present embodiment and a lattice marker 15 according to the conventional method are attached to a columnar structure having a cylindrical shape with a diameter of 50 mm at a height of 1.5 m from the ground.
  • the measurement result of the displacement of the horizontal direction 16 of the columnar structure by the method of this embodiment and the conventional method, and a frequency is compared.
  • the marker by the conventional method and the marker by the method of this embodiment are attached to this columnar structure at the position of the surface height of a columnar structure as a reference
  • Vibrations in the horizontal direction 16 were applied 30 seconds after the start of measurement, vibrations in the front-rear direction 17 were applied 60 seconds after the start of measurement, and movie shooting was performed with the cinema camera 13 at a sampling rate of 24 fps (Frame Per Sec). .
  • the distance between the column structure and the camera is 3 m.
  • the grating pitch of the oblique grating 14 according to the method of the present embodiment is set to 10 mm, and the grating angle is set to 45 °.
  • a grating marker 15 according to the prior art a vertical grating having a grating pitch of 10 mm is used.
  • Vibration analysis was performed by performing FFT frequency analysis processing on the displacement measurement results.
  • the method of Example 3 of International Publication WO2018 / 061321 is incorporated.
  • the analysis of the displacement amount is performed in the X direction in the conventional method, whereas the analysis is performed in the Y direction in the method of the present embodiment.
  • FIG. 19A shows the measurement result of displacement according to the conventional method
  • FIG. 19B shows the measurement result of displacement according to the method of the present embodiment. From the measurement results of this displacement, it is confirmed that the displacement is measured with an accuracy of 0.3 mm or less, as in the conventional method, even in the method of the present embodiment.
  • FIG. 20A shows the measurement result of vibration at rest (30 seconds from the start of measurement) by the conventional method
  • FIG. 20B shows the measurement result of vibration at rest (30 seconds from the start of measurement) by the method of this embodiment. . From the measurement results of this vibration, it was confirmed that the frequency component is calculated also in the method of the present embodiment as in the conventional method.
  • FIG. 21A shows the measurement result of vibration at the time of applying vibration in the horizontal direction 16 (between 30 seconds and 60 seconds after the start of measurement) by the conventional method
  • FIG. 21B shows the vibration in the horizontal direction 16 by the method of this embodiment.
  • the measurement result of a vibration at the time of an application is shown. From this measurement result, it was confirmed that the frequency component can be calculated also in the method of the present embodiment as in the conventional method when applying vibration in the horizontal direction 16.
  • FIG. 22A shows measurement results of vibration during vibration application in the front-rear direction 17 (after 60 seconds from the start of measurement) according to the conventional method
  • FIG. 22B shows vibration during vibration application in the front-back direction 17 according to the method of this embodiment (measurement The measurement result of the vibration after 60 seconds has passed since the start is shown. From the measurement results of this vibration, it was confirmed that the frequency component is calculated in the same manner as the conventional method, even when vibration in the front-rear direction 17 is applied, by the analysis method of the longitudinal direction of the columnar structure of this embodiment.
  • the restriction of the grid attachment in the displacement analysis by the sampling moire method is alleviated, so that the grid can be attached to measurement objects of various shapes. Therefore, the measurement system 100 can measure the displacement without being restricted by the shape of the structure or the measurement target.
  • displacement measurement can be performed at various places such as a road center by attaching the oblique grid 22 to a thin box-shaped block or hump. .
  • the method according to this embodiment makes it possible to measure in-plane or out-of-plane displacement or vibration of variously shaped structures without being restricted by the shape of the structures. .
  • microstructures such as MEMS (Mems, Micro Electro Mechanical Systems) machines to large structures such as bridges, tunnels or high-rise buildings which are social infrastructures, more accurately and more easily It is possible to measure displacement or vibration.
  • MEMS Micro Electro Mechanical Systems
  • Measurement System 200 Sample 201 Measurement Region 202 Diagonal Grating 300 Imager 411 Acquisition Unit 412 First Calculation Unit 413 Second Calculation Unit

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Abstract

La présente invention permet de mesurer de façon plus appropriée le déplacement ou la vibration d'une région de mesure. Ce procédé de mesure est utilisé dans un système de mesure qui comprend un dispositif d'imagerie et un dispositif de traitement d'informations, dans lequel : le dispositif d'imagerie capture des images avant et après la déformation d'une région de mesure à laquelle une grille diagonale est fixée de sorte que la direction de grand côté d'une région de mesure rectangulaire qui fait partie d'un échantillon et la direction de grand côté de la grille diagonale rectangulaire correspondent ; et le dispositif de traitement d'informations calcule la différence de phase de la grille diagonale dans la direction de grand côté à partir des images capturées avant et après la déformation par analyse de moiré et calcule le déplacement ou la vibration avant et après la déformation de la région de mesure dans la direction courte sur la base de la différence de phase calculée dans la direction longue.
PCT/JP2018/033450 2017-10-24 2018-09-10 Procédé de mesure, programme informatique et système de mesure WO2019082528A1 (fr)

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Citations (2)

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JP5818218B2 (ja) * 2012-03-14 2015-11-18 国立研究開発法人産業技術総合研究所 高次元輝度情報を用いた縞画像の位相分布解析方法、装置およびそのプログラム
WO2018061321A1 (fr) * 2016-09-27 2018-04-05 国立研究開発法人産業技術総合研究所 Dispositif et procédé de mesure de forme tridimensionnelle, de déplacement et de contrainte utilisant un motif périodique, et programme associé

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JP5818218B2 (ja) * 2012-03-14 2015-11-18 国立研究開発法人産業技術総合研究所 高次元輝度情報を用いた縞画像の位相分布解析方法、装置およびそのプログラム
WO2018061321A1 (fr) * 2016-09-27 2018-04-05 国立研究開発法人産業技術総合研究所 Dispositif et procédé de mesure de forme tridimensionnelle, de déplacement et de contrainte utilisant un motif périodique, et programme associé

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