WO2020003762A1 - Shape measuring device and shape measuring method - Google Patents

Shape measuring device and shape measuring method Download PDF

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Publication number
WO2020003762A1
WO2020003762A1 PCT/JP2019/018683 JP2019018683W WO2020003762A1 WO 2020003762 A1 WO2020003762 A1 WO 2020003762A1 JP 2019018683 W JP2019018683 W JP 2019018683W WO 2020003762 A1 WO2020003762 A1 WO 2020003762A1
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Prior art keywords
pattern
light
image
wavelength band
shape
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PCT/JP2019/018683
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French (fr)
Japanese (ja)
Inventor
北村　藤和
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株式会社Ｓｃｒｅｅｎホールディングス
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Publication of WO2020003762A1 publication Critical patent/WO2020003762A1/en

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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
    • G01B11/24—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
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/50—Depth or shape recovery
    • G06T7/521—Depth or shape recovery from laser ranging, e.g. using interferometry; from the projection of structured light

Definitions

  • the present invention relates to a shape measuring device and a shape measuring method for measuring a shape of an object in a non-contact manner.
  • CROSS REFERENCE TO RELATED APPLICATIONS The disclosures in the specification, drawings and claims of the following Japanese application are hereby incorporated by reference in their entirety: Japanese Patent Application No. 2018-123055 (filed on June 28, 2018).
  • Patent Literature 1 describes a shape measurement method for obtaining a three-dimensional spatial coordinate of an object by a shadow-moire method of a real lattice type.
  • a grid plate having a grid pattern is arranged near an object, and illumination light emitted from a light source such as a halogen lamp is applied to the object via the grid plate.
  • a lattice pattern is projected on the surface of the object.
  • moiré fringes generated by the lattice pattern and the lattice pattern are imaged by an imaging unit such as a camera, and the three-dimensional spatial coordinates of the object are obtained from the imaging result.
  • the shape of the object can be measured by optimizing the grid pitch of the grid pattern and the resolution of the imaging unit. Can be performed favorably.
  • these shape measuring techniques are not always versatile, and there is a problem that it is difficult to accurately measure the shape of an object having a relatively large stepped portion such as a stepped gear.
  • the present invention has been made in view of the above problems, and has as its object to provide a shape measuring device and a shape measuring method capable of accurately measuring the shape of an object even when the object has a stepped portion.
  • One aspect of the present invention is a shape measuring device for measuring a shape of an object in a non-contact manner, the pattern measuring device including a pattern image arranged in a first direction away from the object and set based on a spatial coding method.
  • a projection unit that emits the pattern light of the first wavelength band toward the object; and a projection unit that is arranged away from the object in a first direction and emits illumination light of a second wavelength band different from the first wavelength band toward the object.
  • a light source unit which is disposed between the object, the light source unit, and the projection unit in the first direction, transmits all light in the first wavelength band, and partially blocks light in the second wavelength band.
  • An image capturing unit that obtains a moire fringe image generated by superimposing an image of an object and a lattice pattern image by capturing an object onto which a lattice pattern corresponding to a pattern is projected, and a moire fringe image and pattern projection captured by the image capturing unit.
  • Another aspect of the present invention is a shape measuring method for measuring a shape of an object in a non-contact manner, wherein pattern light of a first wavelength band including a pattern image set based on a spatial coding method is applied to a surface of the object.
  • It is characterized by comprising a measurement step and a coordinate determination step of obtaining three-dimensional spatial coordinates of the object based on the Moire fringe image and the pattern projection image.
  • the shape measurement of the object based on the moiré fringe image (shadow moiré method)
  • the shadow moiré method with the space coding method based on the pattern image, the three-dimensional spatial coordinates of the object can be obtained well.
  • the shadow moiré method and the space coding method are used to determine the three-dimensional spatial coordinates of the object, not only objects having no step portion but also objects having a step portion Can be accurately measured.
  • All of the plurality of constituent elements of each embodiment of the present invention described above are not essential.
  • technical features included in one embodiment of the present invention described above are described. Some or all of them may be combined with some or all of the technical features included in the other aspects of the present invention described above to form an independent embodiment of the present invention.
  • FIG. 2 is a diagram schematically illustrating an internal structure of a measuring head provided in the shape measuring device in FIG. 1.
  • 5 is a graph showing transmittance characteristics of a lattice pattern.
  • 3 is a flowchart showing a shape measuring operation by the shape measuring device shown in FIG. 1. It is a figure which shows a shape measurement operation typically. It is a figure showing a 2nd embodiment of the shape measuring device of the object concerning the present invention. It is a figure showing typically an example of an appearance inspection device provided with a 3rd embodiment of a shape measuring device concerning the present invention. It is a figure showing a 4th embodiment of an object shape measuring device concerning the present invention.
  • FIG. 1 is a view showing a first embodiment of an object shape measuring apparatus according to the present invention.
  • This shape measuring device 1A is a device that measures the shape of the object W in a state where the object W having a relatively large stepped portion Wa such as a stepped gear is stationary.
  • XYZ coordinate axes are set as shown in FIG.
  • the XY plane is the horizontal plane
  • the Z axis coincides with the vertical axis.
  • the positive direction on the Z axis is a vertically upward direction.
  • the shape measuring apparatus 1A includes the holding unit 2 that holds the object W to be measured in a stationary state.
  • a columnar member 3 stands upright in the vertical direction Z from the holding portion 2, and a measuring head 4 is attached to an upper end of the columnar member 3 so as to be able to move up and down in the Z direction.
  • a grid plate 5 is mounted so as to be able to move up and down in the Z direction.
  • the measuring head 4 and the grid plate 5 are connected to a lifting unit 6.
  • the elevation unit 6 operates in response to an elevation command from the control unit 10 that controls the entire apparatus, so that the measurement head 4 and the grid plate 5 are moved according to the dimension of the object W in the vertical direction Z, that is, the object height.
  • the grid plate 5 is moved up and down integrally, and positioned at a position directly above the object W. After the positioning of the grating plate 5 is completed, the first shape measurement step and the second shape measurement step are respectively performed by the projector, the light source unit, and the imaging unit incorporated in the measurement head 4.
  • the first shape measuring step and the second shape measuring step correspond to examples of the “first shape measuring process” and “second shape measuring process” of the present invention, respectively.
  • FIG. 2 is a view schematically showing the internal structure of the measuring head.
  • the projector 7, the light source unit 8, and the imaging unit 9 incorporated in the measuring head 4 are all spaced apart from the object W in the (+ Z) direction, and face the surface of the object W with the grid plate 5 interposed therebetween. I have. Among them, the projector 7 emits the pattern light L1 of the first wavelength band ⁇ 1 including the pattern image set based on the spatial coding method toward the object W. The pattern light L1 is applied to the object W via the grating plate 5 in the first shape measurement step as shown in the column (a) of FIG. In the present embodiment, a gray code is used as the pattern image, and the projector 7 corresponds to an example of the “projection unit” of the invention.
  • the light source unit 8 has three light sources 81 to 83 arranged in a line while being separated from each other by a predetermined distance in the X direction.
  • Each of the light sources 81 to 83 is a point light source composed of an LED (Light Emitting Diode) or an LD (Laser Diode), and can emit illumination light L2 in the second wavelength band ⁇ 2 ( ⁇ ⁇ 1).
  • the first wavelength band ⁇ 1 and the second wavelength band ⁇ 2 can be referred to as a “red wavelength band” and a “blue wavelength band”, respectively.
  • the light sources 81 to 83 can be turned on and off independently of each other in accordance with a lighting command from the control unit 10. Then, in the second shape measurement step, the light source 81 located at the uppermost stream in the X direction is turned on for a certain time as shown in the column (b) of FIG. That is, the light source 81 is turned off after the object W is irradiated with the illumination light L2 via the lattice plate 5. Subsequently, the light sources 82 and 83 are turned on for a certain period of time in the same order as the light source 81 and then turned off.
  • the lattice plate 5 is configured as follows.
  • the grating plates 5 are provided at a predetermined pitch on the (+ Z) direction main surface of the flat substrate 51 and are spaced apart from each other by a sine wave grid pattern.
  • the flat substrate 51 is made of a glass plate, a plastic plate, or the like, and has a first optical property of transmitting light in the first wavelength band ⁇ 1 and the second wavelength band ⁇ 2.
  • each pattern member 52 is manufactured by patterning a dielectric film or the like, and as shown in FIG. 3, transmits the light of the first wavelength band ⁇ 1 and blocks the light of the second wavelength band ⁇ 2. Having the second optical characteristic.
  • the vertical and horizontal axes in FIG. 3 indicate “transmittance” and “wavelength”, respectively.
  • the pattern light L1 of the first wavelength band ⁇ 1 is irradiated to the grating plate 5 configured as described above, and the pattern light L1 passes through the grating plate 5 and irradiates the object W as it is.
  • the gray code is projected on the surface of the object W, and the shape of the object W can be measured by a conventionally known spatial coding method (first shape measurement step).
  • the illumination light L2 of the second wavelength band ⁇ 2 is applied to the grating plate 5
  • the light applied to the pattern member 52 of the illumination light L2 is blocked by the pattern member 52, and the rest is transmitted through the flat base material 51. Then, the object W is irradiated.
  • the grating plate 5 functions as a grating that does not transmit only the specific second wavelength band ⁇ 2.
  • the imaging unit 9 includes a monochrome imaging device 91 that acquires a monochrome image, and an imaging lens 92 that forms an image of the object W on an imaging surface 911 (see FIG. 5) of the monochrome imaging device 91.
  • a monochrome imaging device 91 that acquires a monochrome image
  • an imaging lens 92 that forms an image of the object W on an imaging surface 911 (see FIG. 5) of the monochrome imaging device 91.
  • the gray code is projected on the surface of the object W
  • the monochrome image sensor 91 images the object W.
  • the image thus captured is an example of the “pattern projection image” of the present invention, and the image data is transferred from the monochrome image sensor 91 to the control unit 10, and the shape of the object W can be measured by the spatial coding method. (First shape measurement step).
  • the lattice image is projected on the surface of the object W as described above. Since the image capturing unit 9 captures the object W on which the lattice image is projected in this way via the lattice plate 5, the image captured by the monochrome image sensor 91 includes the image of the object W on which the lattice image is projected and the sinusoidal image. A moire fringe image generated by superimposing images of the wave grating pattern is included. This image data is transferred from the monochrome image sensor 91 to the control unit 10, and the shape of the object W can be measured by the shadow moire method (second shape measurement step).
  • the grid pattern is moved on the surface of the object W by sequentially causing the light sources 81 to 83 to emit light at different timings in order to execute the shadow moiré method with a phase shift as described in detail later. ing. Then, the image of the moving lattice pattern is captured by the imaging unit 9.
  • CPU Central Processing Unit
  • RAM Random Access Unit
  • FIG. 4 is a flowchart showing a shape measuring operation by the shape measuring apparatus shown in FIG.
  • FIG. 5 is a diagram schematically illustrating the shape measuring operation.
  • the shape measuring apparatus 1A when the object W to be measured is held by the holding unit 2, the first shape measuring step (Step S1), the second shape measuring step (Step S2), and the coordinate determination step (Step S3) are performed. Execute in this order.
  • the projector 7 emits the pattern light L1 of the first wavelength band ⁇ 1 including the gray code toward the object W while the light sources 81 to 83 are turned off, and outputs the object light via the grating plate 5. Irradiate W.
  • the gray code is projected on the surface of the object W (step S1-1).
  • the pattern light L1 is light of the wavelength band ⁇ 1, it is not affected by the sine wave grating pattern G, and passes through the grating plate 5 as it is as shown in the column (a) of FIG. Irradiated on the surface.
  • step S1-3 the direction of the point P viewed from the imaging unit 9, which is obtained from the projected coordinates C (x, y) on the imaging surface 911 of the monochrome imaging device 91, That is, the angle ⁇ with respect to the vertical direction Z is calculated (step S1-3). Further, a fan-shaped area is specified from the light-dark pattern (projection light code) of the gray code at the coordinates C (x, y), and the projection direction of the projection light in the fan-shaped area to the point P, that is, the angle ⁇ ⁇ ⁇ ⁇ with respect to the vertical direction Z Is calculated (step S1-4).
  • the Z-axis coordinates of the point P in the vertical direction Z are calculated based on the principle of triangulation (step S1-5), and the X and Y coordinates of the point P are calculated (step S1-6).
  • the three-dimensional position of the point P thus calculated that is, the three-dimensional coordinates P (X, Y, Z) is stored in the memory of the control unit 10.
  • the origin of the three-dimensional coordinates is set to the principal point O of the imaging lens 92.
  • step S1 When the shape measurement of the object W by the space coding method, that is, the first shape measurement step (step S1) is completed, the third order of the point P of the object W is obtained by the shadow moire method with phase shift, for example, the method described in Patent Document 1.
  • the original coordinates (X, Y, Z) are measured (second shape measuring step: step S2).
  • step S2 second shape measuring step: step S22
  • the light source 81 is turned on and the illumination light L2 of the second wavelength band ⁇ 2 is emitted toward the object W as shown in a section (b) of FIG.
  • a lattice image corresponding to the sinusoidal lattice pattern G is projected on the surface of the object W (step S2-1).
  • the monochrome image sensor 91 captures an image of the object W on which the lattice pattern is projected via the lattice plate 5.
  • the light source 82 is turned on after the light source 81 is turned off, and the object W on which the grid pattern is projected via the grid plate 5 is imaged in the same manner as when the light source 81 is turned on.
  • the light source 83 is turned on, and the object W on which the grid pattern is projected via the grid plate 5 is imaged in the same manner as when the light sources 81 and 82 are turned on.
  • step S2-2 the point P (X, Y, Z) of the object W
  • the phase value ⁇ (x, y) is calculated from the coordinates C (x, y) on the imaging surface 911 (step S2-3).
  • the intersection point between the lattice plane of the sine wave lattice pattern G and the optical axis OA of the imaging unit 9 is set as the origin.
  • the phase value ⁇ (x, y) is determined when the shape of the object W to be measured is continuously changing or when the stepped portion Wa is within one pitch of the pattern member 52 constituting the sine wave grating pattern G.
  • 2 ⁇ may be simply added.
  • the phase jump corresponds to a multiple of 2 ⁇ , that is, the stripe order n (x, y) Need to ask.
  • a coordinate determination step (step S3) is executed.
  • the stripe order n (x, y) is determined based on the three-dimensional coordinates (X, Y, Z) of the point P obtained in the first shape measurement step (step S1) (step S3-1). ).
  • an unwrapping process is performed using the stripe order n (x, y), and the three-dimensional coordinates (X, Y, Z) calculated thereby are set as the three-dimensional position of the point P (step S3-2).
  • the object W in which the shape of the object W is continuously changing or the object W having the stepped portion Wa but within one pitch of the pattern member 52 the object W can be obtained with high accuracy by combining the phase shift with the shadow moire method.
  • W shape measurement can be performed.
  • a step portion Wa exceeding one pitch exists in the object W a phase wrap (jump) occurs.
  • the unwrapping process is executed based on the position information obtained by the spatial coding method. I have. Therefore, the shape measurement of the object W having the stepped portion Wa as well as the object W having no stepped portion Wa can be performed with high accuracy.
  • the shape of the object W is measured by replacing the grating plate 5 with a grating pitch (pitch between the adjacent pattern members 52) suitable for the stepped portion Wa. Need to do.
  • the shape of the object W can be measured with high accuracy without changing the grid plate 5 by combining the spatial coding method based on the pattern image as described above.
  • FIG. 6 is a view showing a second embodiment of the object shape measuring apparatus according to the present invention.
  • the point that the shape measuring apparatus 1B according to the second embodiment is significantly different from the first embodiment is that the shape of the object W is conveyed in the horizontal direction X by circulating the conveyor 22 by the conveyor driving unit 21.
  • the point is that the measurement is performed and the phase shift is performed by moving the object W instead of performing the phase shift by switching the light sources 81 to 83 in the second shape measurement step. This is the same as in the first embodiment.
  • the second embodiment since the shadow moiré method with a phase shift and the space coding method are combined, the shape measurement of the object W can be performed with high accuracy regardless of the presence or absence of the stepped portion Wa.
  • the conveyor 22 corresponds to an example of the “moving unit” of the present invention.
  • the shape measuring device 1B configured as described above may be incorporated in a so-called visual inspection device that checks whether or not the object W has a defect such as a scratch as shown in FIG.
  • a so-called visual inspection device that checks whether or not the object W has a defect such as a scratch as shown in FIG.
  • the appearance inspection apparatus there is one described in, for example, JP-A-2017-227621.
  • This appearance inspection device performs an appearance inspection of a metal product in order to examine the presence or absence of a defect in a metal product (corresponding to an example of the “object” of the present invention) manufactured by forging, casting, or the like, and performs a shape inspection of the metal product. A defect area including a defect is extracted. Therefore, as shown in FIG.
  • the visual inspection unit 120 performs the visual inspection while the object (metal product) W is transported in a predetermined direction by the transport mechanism 110 such as a conveyor, and the defect is detected by the shape measuring unit 130. You may comprise so that the shape measurement of an area
  • the configuration and operation of the visual inspection device 100 will be described with reference to FIG.
  • FIG. 7 is a view schematically showing an example of a visual inspection device equipped with a third embodiment of the shape measuring device according to the present invention.
  • the object W to be subjected to the appearance inspection is transported in the horizontal direction by the transport mechanism 110. Further, the appearance inspection unit 120 and the shape measurement unit 130 are provided side by side along the transport path of the object W.
  • the appearance inspection unit 120 is arranged on the upstream side of the shape measurement unit 130 in the transport direction of the object W (on the left hand side in the drawing).
  • an imaging camera 121 is disposed vertically above the transport mechanism 110. Further, two lighting fixtures 122 and 123 are arranged diagonally above the transport mechanism 110 so as to sandwich the imaging camera 121.
  • data of a reference image acquired by imaging the object W determined in advance as a non-defective product with the imaging camera 121 is stored.
  • the image of the object W is captured by the imaging camera 121, and the captured image is compared with the reference image to determine the presence or absence of a defect. I do.
  • the shape measuring unit 130 is provided downstream of the visual inspection unit 120 in the transport direction X of the object W.
  • two sets of shape measuring units 131 for measuring the shape of the object W with the measuring head 4 and the grid plate 5 are provided diagonally above the transport mechanism 110 as in the above embodiment.
  • a robot arm (not shown) is connected to each shape measuring unit 131, and the shape is measured by the shape measuring unit 131 in an arbitrary posture with respect to the object W conveyed from the visual inspection unit 120 by the conveying mechanism 110. Is executable.
  • Each of the shape measuring units 131 is in a state where the posture is controlled so as to face the defect area found by the appearance inspection unit 120, and the first shape measuring step, the second shape measuring step, and the coordinate determination are performed similarly to the above embodiment.
  • the process is executed to measure the shape of the defect area in detail, and the measurement result is output.
  • the appearance inspection apparatus 100 illustrated in FIG. 7 it is possible to find out a defect region existing on the surface of the object W and perform detailed shape measurement thereof, and to inspect the object W with high accuracy. It can be carried out.
  • the object W is transported to the shape measurement unit 130 by the transportation mechanism 110 in the posture when inspected by the appearance inspection unit 120.
  • a reversing mechanism (not shown) for adjusting the posture of the object W, for example, for reversing the object W, may be provided between the unit 130 and the unit 130, whereby the range that can be measured by the shape measuring unit 130 can be expanded.
  • the present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention.
  • the first shape measurement step (step S1) and the second shape measurement step (step S2) are performed in this order by using the monochrome image sensor 91, but the order is reversed. Is also good.
  • the first shape measuring step (step S1) and the second shape measuring step (step S2) may be performed simultaneously by using a color image sensor such as a color CCD or a color CMOS instead of the monochrome image sensor 91. In this case, the time required for shape measurement can be reduced.
  • step S1 In order to simultaneously perform the first shape measurement step (step S1) and the second shape measurement step (step S2), instead of the monochrome image sensor 91, as shown in FIG. 94 and a color separation element 95 such as a dichroic mirror may be provided (fourth embodiment).
  • FIG. 8 is a view showing a fourth embodiment of the object shape measuring apparatus according to the present invention.
  • the fourth embodiment when the first shape measurement step (step S1) and the second shape measurement step (step S2) are performed simultaneously, light of the first wavelength band ⁇ 1 and light of the second wavelength band ⁇ 2 are not used.
  • a color separation element 95 is arranged on the emission side of the imaging lens 92. The color separation element 95 reflects the light in the first wavelength band ⁇ 1 to guide the light to the first monochrome image sensor 93 and transmits the light in the second wavelength band ⁇ 2 as it is to guide the light to the second monochrome image sensor 94. .
  • the first monochrome image sensor 93 receives light in the first wavelength band and the first shape measurement step (step S1)
  • the second monochrome image sensor 94 receives light in the second wavelength band and performs second shape measurement.
  • the step (step S2) can be performed simultaneously, and the time required for shape measurement can be reduced.
  • point light sources are used as the three light sources 81 to 83 in order to execute the second shape measurement step (step S2), but line light sources may be used. Further, the number of light sources is not limited to “3”, and may be four or more.
  • the phase shift is used in combination.
  • the use of the phase shift is suitable for increasing the accuracy of the shape measurement, but the space is one of the technical features of the present invention. It is not an indispensable configuration for the combination with the coding method, but an optional configuration.
  • the present invention can be applied to all shape measurement techniques for measuring the shape of an object in a non-contact manner.
  • Shape measuring device 5 Lattice plate 7: Projector (projection unit) 8 light source unit 9 imaging unit 10 control unit 22 conveyor (moving unit) Reference Signs List 51: Flat substrate 52: Pattern member 81 to 83: Light source 91: Monochrome imaging device 93: First monochrome imaging device 94: Second monochrome imaging device 95: Color separation device 131: Shape measuring unit (shape measuring device) G: sine wave grating pattern L1: pattern light L2: illumination light ⁇ 1: first wavelength band ⁇ 2: second wavelength band W: object Wa: stepped portion X: horizontal direction (second direction) Z: Vertical direction (first direction)

Abstract

The present invention accurately measures the shape of an object even when the object has a stepped part. This shape measuring device is provided with: a projection unit that emits, toward the object, pattern light of a first wavelength band including a pattern image set on the basis of a spatial coding method; a light source that emits illumination light of a second wavelength band different from the first wavelength band toward the object; and a grating plate that forms a grating pattern by partially blocking light of the second wavelength band and while transmitting the entire light of the first wavelength band. Three-dimensional space coordinates of the object are determined on the basis of a pattern projection image acquired by imaging the object to which a pattern image has been projected and a moire stripe image generated by superimposing together an image of the object and an image of the grating pattern through imaging of the object to which a lattice pattern corresponding to the grating pattern has been projected.

Description

形状測定装置および形状測定方法Shape measuring device and shape measuring method
　この発明は、物体の形状を非接触で測定する形状測定装置および形状測定方法に関するものである。
関連出願の相互参照
　以下に示す日本出願の明細書、図面および特許請求の範囲における開示内容は、参照によりその全内容が本書に組み入れられる：
　特願２０１８－１２３０５５（２０１８年６月２８日出願）。 The present invention relates to a shape measuring device and a shape measuring method for measuring a shape of an object in a non-contact manner.
CROSS REFERENCE TO RELATED APPLICATIONS The disclosures in the specification, drawings and claims of the following Japanese application are hereby incorporated by reference in their entirety:
Japanese Patent Application No. 2018-123055 (filed on June 28, 2018).
　金属製部品、樹脂製部品やゴム製部品などの立体的な物体の三次元形状を非接触で測定する技術として、光を利用したものが多用されている。その一例として、特許文献１では、実体格子型のシャドーモワレ法により物体の三次元空間座標を求める形状測定方法が記載されている。この形状測定方法では、格子パターンを有する格子プレートが物体の近傍に配置され、ハロゲンランプなどの光源から出射した照明光が格子プレートを介して物体に照射される。これによって物体の表面に格子模様が投影される。また、格子パターンと格子模様とにより生じるモワレ縞をカメラなどの撮像部により撮像し、その撮像結果から物体の三次元空間座標を求めている。 光 Light is widely used as a technology for non-contact measurement of the three-dimensional shape of three-dimensional objects such as metal parts, resin parts, and rubber parts. As one example, Patent Literature 1 describes a shape measurement method for obtaining a three-dimensional spatial coordinate of an object by a shadow-moire method of a real lattice type. In this shape measurement method, a grid plate having a grid pattern is arranged near an object, and illumination light emitted from a light source such as a halogen lamp is applied to the object via the grid plate. As a result, a lattice pattern is projected on the surface of the object. In addition, moiré fringes generated by the lattice pattern and the lattice pattern are imaged by an imaging unit such as a camera, and the three-dimensional spatial coordinates of the object are obtained from the imaging result.
特開平４－１４７００１号公報JP-A-4-147001
　上記したシャドーモワレ法を用いた形状測定技術、あるいはシャドーモワレ法に位相シフトを組み合わせた形状測定技術によれば、格子パターンの格子ピッチおよび撮像部の分解能などを適正化することで物体の形状測定を良好に行うことができる。しかしながら、これらの形状測定技術は必ずしも万能であるとは言えず、例えば段付き歯車のように比較的大きな段差部位を有する物体については正確な形状測定が難しいという問題を有していた。 According to the shape measurement technology using the shadow moiré method described above or the shape measurement technology that combines the phase shift with the shadow moiré method, the shape of the object can be measured by optimizing the grid pitch of the grid pattern and the resolution of the imaging unit. Can be performed favorably. However, these shape measuring techniques are not always versatile, and there is a problem that it is difficult to accurately measure the shape of an object having a relatively large stepped portion such as a stepped gear.
　この発明は上記課題に鑑みなされたものであり、物体が段差部位を有する場合であっても、当該物体の形状を正確に測定することができる形状測定装置および形状測定方法を提供することを目的とする。 The present invention has been made in view of the above problems, and has as its object to provide a shape measuring device and a shape measuring method capable of accurately measuring the shape of an object even when the object has a stepped portion. And
　この発明の一態様は、物体の形状を非接触で測定する形状測定装置であって、物体から第１の方向に離間して配置され、空間コード化法に基づいて設定されるパターン画像を含む第１波長帯域のパターン光を物体に向けて出射する投影部と、物体から第１の方向に離間して配置され、第１波長帯域と異なる第２波長帯域の照明光を物体に向けて出射する光源部と、第１の方向において物体と光源部および投影部との間に配置され、第１波長帯域の光については全部を透過させ、第２波長帯域の光については一部を遮光して格子パターンを形成する格子プレートと、格子プレートを介して物体を撮像可能に設けられ、パターン光の照射によりパターン画像が投影された物体を撮像してパターン投影画像を取得し、照明光の照射により格子パターンに対応する格子模様が投影された物体を撮像することで物体の像と格子パターンの像を重ねて生じるモワレ縞画像を取得する撮像部と、撮像部により撮像されたモワレ縞画像およびパターン投影画像に基づいて物体の三次元空間座標を求める制御部とを備えることを特徴としている。 One aspect of the present invention is a shape measuring device for measuring a shape of an object in a non-contact manner, the pattern measuring device including a pattern image arranged in a first direction away from the object and set based on a spatial coding method. A projection unit that emits the pattern light of the first wavelength band toward the object; and a projection unit that is arranged away from the object in a first direction and emits illumination light of a second wavelength band different from the first wavelength band toward the object. And a light source unit, which is disposed between the object, the light source unit, and the projection unit in the first direction, transmits all light in the first wavelength band, and partially blocks light in the second wavelength band. A grid plate for forming a grid pattern, and an object that is provided so as to be able to image the object through the grid plate, and obtains a pattern projection image by imaging the object on which the pattern image is projected by irradiating the pattern light, By lattice putter An image capturing unit that obtains a moire fringe image generated by superimposing an image of an object and a lattice pattern image by capturing an object onto which a lattice pattern corresponding to a pattern is projected, and a moire fringe image and pattern projection captured by the image capturing unit. And a control unit for obtaining three-dimensional spatial coordinates of the object based on the image.
　また、この発明の他の態様は、物体の形状を非接触で測定する形状測定方法であって空間コード化法に基づいて設定されるパターン画像を含む第１波長帯域のパターン光を物体の表面に照射してパターン画像を投影するとともに、パターン画像が投影された物体を撮像してパターン投影画像を取得する第１形状測定工程と、第１波長帯域と異なる第２波長帯域の照明光を格子パターンを介して物体の表面に照射して格子模様を投影するとともに、格子模様が投影された物体を撮像して物体の像と格子パターンの像を重ねて生じるモワレ縞画像を取得する第２形状測定工程と、モワレ縞画像およびパターン投影画像に基づいて物体の三次元空間座標を求める座標確定工程とを備えることを特徴としている。 Another aspect of the present invention is a shape measuring method for measuring a shape of an object in a non-contact manner, wherein pattern light of a first wavelength band including a pattern image set based on a spatial coding method is applied to a surface of the object. A first shape measuring step of projecting a pattern image by irradiating the object with a pattern image and capturing an object on which the pattern image is projected to obtain a pattern projection image; A second shape for projecting the lattice pattern by irradiating the surface of the object via the pattern, capturing the object on which the lattice pattern is projected, and acquiring a moire fringe image generated by superimposing the image of the object and the image of the lattice pattern It is characterized by comprising a measurement step and a coordinate determination step of obtaining three-dimensional spatial coordinates of the object based on the Moire fringe image and the pattern projection image.
　モワレ縞画像に基づく物体の形状測定（シャドーモワレ法）では、第１の方向において物体の表面が大きく変動する部分（つまり段差部分）が存在する物体の表面を高精度に測定することが難しかった。これに対し、シャドーモワレ法に対してパターン画像に基づく空間コード化法を組み合わせることで物体の三次元空間座標が良好に求められる。 In the shape measurement of the object based on the moiré fringe image (shadow moiré method), it has been difficult to measure the surface of the object having a portion where the surface of the object greatly fluctuates in the first direction (that is, a step portion) with high accuracy. . On the other hand, by combining the shadow moiré method with the space coding method based on the pattern image, the three-dimensional spatial coordinates of the object can be obtained well.
　以上のように、シャドーモワレ法と空間コード化法とを組み合わせて物体の三次元空間座標を求めているため、段差部位を有さない物体はもちろんのこと、段差部位を有する物体についても当該物体の形状を正確に測定することができる。
　上述した本発明の各態様の有する複数の構成要素はすべてが必須のものではなく、上述の課題の一部又は全部を解決するため、あるいは、本明細書に記載された効果の一部又は全部を達成するために、適宜、前記複数の構成要素の一部の構成要素について、その変更、削除、新たな他の構成要素との差し替え、限定内容の一部削除を行うことが可能である。また、上述の課題の一部又は全部を解決するため、あるいは、本明細書に記載された効果の一部又は全部を達成するために、上述した本発明の一態様に含まれる技術的特徴の一部又は全部を上述した本発明の他の態様に含まれる技術的特徴の一部又は全部と組み合わせて、本発明の独立した一形態とすることも可能である。 As described above, since the shadow moiré method and the space coding method are used to determine the three-dimensional spatial coordinates of the object, not only objects having no step portion but also objects having a step portion Can be accurately measured.
All of the plurality of constituent elements of each embodiment of the present invention described above are not essential. To solve some or all of the above-described problems, or some or all of the effects described in the present specification. In order to achieve the above, it is possible to appropriately change or delete some of the plurality of components, replace them with other new components, and partially delete the limited contents. In addition, in order to solve some or all of the above problems or to achieve some or all of the effects described in this specification, technical features included in one embodiment of the present invention described above are described. Some or all of them may be combined with some or all of the technical features included in the other aspects of the present invention described above to form an independent embodiment of the present invention.
本発明に係る物体の形状測定装置の第１実施形態を示す図である。It is a figure showing a 1st embodiment of a shape measuring device of an object concerning the present invention. 図１の形状測定装置に装備される測定ヘッドの内部構造を模式的に示す図である。FIG. 2 is a diagram schematically illustrating an internal structure of a measuring head provided in the shape measuring device in FIG. 1. 格子パターンの透過率特性を示すグラフである。5 is a graph showing transmittance characteristics of a lattice pattern. 図１に示す形状測定装置による形状測定動作を示すフローチャートである。3 is a flowchart showing a shape measuring operation by the shape measuring device shown in FIG. 1. 形状測定動作を模試的に示す図である。It is a figure which shows a shape measurement operation typically. 本発明に係る物体の形状測定装置の第２実施形態を示す図である。It is a figure showing a 2nd embodiment of the shape measuring device of the object concerning the present invention. 本発明に係る形状測定装置の第３実施形態を装備する外観検査装置の一例を模式的に示す図である。It is a figure showing typically an example of an appearance inspection device provided with a 3rd embodiment of a shape measuring device concerning the present invention. 本発明に係る物体の形状測定装置の第４実施形態を示す図である。It is a figure showing a 4th embodiment of an object shape measuring device concerning the present invention.
　図１は本発明に係る物体の形状測定装置の第１実施形態を示す図である。この形状測定装置１Ａは、例えば段付き歯車のように比較的大きな段差部位Ｗａを有する物体Ｗを静止させた状態で物体Ｗの形状を測定する装置である。以後の説明のために、図１に示すようにＸＹＺ座標軸を設定する。ここでＸＹ平面が水平面であり、Ｚ軸は鉛直軸と一致する。また、Ｚ軸における正方向は鉛直上向き方向である。 FIG. 1 is a view showing a first embodiment of an object shape measuring apparatus according to the present invention. This shape measuring device 1A is a device that measures the shape of the object W in a state where the object W having a relatively large stepped portion Wa such as a stepped gear is stationary. For the following description, XYZ coordinate axes are set as shown in FIG. Here, the XY plane is the horizontal plane, and the Z axis coincides with the vertical axis. The positive direction on the Z axis is a vertically upward direction.
　形状測定装置１Ａは、測定対象となる物体Ｗを静止状態で保持する保持部２を有している。この保持部２からは鉛直方向Ｚに柱状部材３が立設され、柱状部材３の上端部に対して測定ヘッド４がＺ方向に昇降自在に取り付けられるとともに、柱状部材３の中間部に対して格子プレート５がＺ方向に昇降自在に取り付けられている。これら測定ヘッド４および格子プレート５は昇降部６と接続されている。そして、装置全体を制御する制御部１０からの昇降指令に応じて昇降部６が作動することで、鉛直方向Ｚにおける物体Ｗの寸法、つまり物体高さに応じて測定ヘッド４および格子プレート５が一体的に昇降し、物体Ｗの直上位置に格子プレート５が位置決めされる。また、格子プレート５の位置決めが完了した後で測定ヘッド４に内蔵されるプロジェクター、光源部および撮像部により第１形状測定工程および第２形状測定工程がそれぞれ実行される。なお、第１形状測定工程および第２形状測定工程がそれぞれ本発明の「第１形状測定処理」および「第２形状測定処理」の一例に相当している。 The shape measuring apparatus 1A includes the holding unit 2 that holds the object W to be measured in a stationary state. A columnar member 3 stands upright in the vertical direction Z from the holding portion 2, and a measuring head 4 is attached to an upper end of the columnar member 3 so as to be able to move up and down in the Z direction. A grid plate 5 is mounted so as to be able to move up and down in the Z direction. The measuring head 4 and the grid plate 5 are connected to a lifting unit 6. The elevation unit 6 operates in response to an elevation command from the control unit 10 that controls the entire apparatus, so that the measurement head 4 and the grid plate 5 are moved according to the dimension of the object W in the vertical direction Z, that is, the object height. The grid plate 5 is moved up and down integrally, and positioned at a position directly above the object W. After the positioning of the grating plate 5 is completed, the first shape measurement step and the second shape measurement step are respectively performed by the projector, the light source unit, and the imaging unit incorporated in the measurement head 4. The first shape measuring step and the second shape measuring step correspond to examples of the “first shape measuring process” and “second shape measuring process” of the present invention, respectively.
　図２は測定ヘッドの内部構造を模式的に示す図である。測定ヘッド４に内蔵されるプロジェクター７、光源部８および撮像部９はいずれも物体Ｗから（＋Ｚ）方向に離間して配置されており、格子プレート５を挟んで物体Ｗの表面と対向している。これらのうちプロジェクター７は空間コード化法に基づいて設定されるパターン画像を含む第１波長帯域λ１のパターン光Ｌ１を物体Ｗに向けて出射する。パターン光Ｌ１は図２の（ａ）欄に示すように第１形状測定工程において格子プレート５を介して物体Ｗに照射される。なお、本実施形態では、上記パターン画像としてグレイコードを用いており、プロジェクター７が本発明の「投影部」の一例に相当している。 FIG. 2 is a view schematically showing the internal structure of the measuring head. The projector 7, the light source unit 8, and the imaging unit 9 incorporated in the measuring head 4 are all spaced apart from the object W in the (+ Z) direction, and face the surface of the object W with the grid plate 5 interposed therebetween. I have. Among them, the projector 7 emits the pattern light L1 of the first wavelength band λ1 including the pattern image set based on the spatial coding method toward the object W. The pattern light L1 is applied to the object W via the grating plate 5 in the first shape measurement step as shown in the column (a) of FIG. In the present embodiment, a gray code is used as the pattern image, and the projector 7 corresponds to an example of the “projection unit” of the invention.
　また、光源部８はＸ方向に互いに所定間隔だけ離間しながら一列に配列された３つの光源８１～８３を有している。光源８１～８３はＬＥＤ（Light Emitting Diode）やＬＤ（Laser Diode）などで構成された点光源であり、いずれも第２波長帯域λ２（≠λ１）の照明光Ｌ２を発光可能となっている。例えば第１波長帯域λ１および第２波長帯域λ２をそれぞれ「赤色の波長帯域」および「青色の波長帯域」とすることができる。 The light source unit 8 has three light sources 81 to 83 arranged in a line while being separated from each other by a predetermined distance in the X direction. Each of the light sources 81 to 83 is a point light source composed of an LED (Light Emitting Diode) or an LD (Laser Diode), and can emit illumination light L2 in the second wavelength band λ2 (≠ λ1). For example, the first wavelength band λ1 and the second wavelength band λ2 can be referred to as a “red wavelength band” and a “blue wavelength band”, respectively.
　光源８１～８３はそれぞれ独立して制御部１０からの点灯指令に応じて点灯および消灯可能となっている。そして、第２形状測定工程では、図２の（ｂ）欄に示すようにＸ方向において最上流に位置する光源８１が一定時間だけ点灯する。すなわち、照明光Ｌ２が格子プレート５を介して物体Ｗに照射された後で光源８１は消灯される。これに続いて、光源８２、８３がこの順序で光源８１と同様に一定時間だけ点灯した後で消灯される。 The light sources 81 to 83 can be turned on and off independently of each other in accordance with a lighting command from the control unit 10. Then, in the second shape measurement step, the light source 81 located at the uppermost stream in the X direction is turned on for a certain time as shown in the column (b) of FIG. That is, the light source 81 is turned off after the object W is irradiated with the illumination light L2 via the lattice plate 5. Subsequently, the light sources 82 and 83 are turned on for a certain period of time in the same order as the light source 81 and then turned off.
　このように互いに異なる波長帯域のパターン光Ｌ１および照明光Ｌ２が格子プレート５に入射されるが、本実施形態では、第１形状測定工程においてパターン光Ｌ１の全部を物体Ｗに投影する一方、第２形状測定工程において第２波長帯域の照明光L２を用いて格子画像を物体Ｗの表面に投影する必要がある。そこで、本実施形態では、格子プレート５は次のように構成されている。 As described above, the pattern light L1 and the illumination light L2 of different wavelength bands are incident on the grating plate 5, but in the present embodiment, the entire pattern light L1 is projected onto the object W in the first shape measurement step, while In the two-shape measurement step, it is necessary to project a lattice image on the surface of the object W using the illumination light L2 in the second wavelength band. Therefore, in the present embodiment, the lattice plate 5 is configured as follows.
　格子プレート５は、図１および図２に示すように、平板基材５１と、平板基材５１の（＋Ｚ）方向側主面上において所定ピッチで相互に離間して設けられて正弦波格子パターン（図５中の符号Ｇ）を構成する複数のパターン部材５２とを有している。平板基材５１はガラス板やプラスチック板などで構成されており、第１波長帯域λ１および第２波長帯域λ２の光を透過させる第１の光学特性を有している。一方、各パターン部材５２は、誘電体膜などをパターニングすることで製造されており、図３に示すように、第１波長帯域λ１の光を透過させる一方で第２波長帯域λ２の光を遮光する第２の光学特性を有している。なお、図３中の縦軸および横軸はそれぞれ「透過率」および「波長」を示している。 As shown in FIGS. 1 and 2, the grating plates 5 are provided at a predetermined pitch on the (+ Z) direction main surface of the flat substrate 51 and are spaced apart from each other by a sine wave grid pattern. (Reference numeral G in FIG. 5). The flat substrate 51 is made of a glass plate, a plastic plate, or the like, and has a first optical property of transmitting light in the first wavelength band λ1 and the second wavelength band λ2. On the other hand, each pattern member 52 is manufactured by patterning a dielectric film or the like, and as shown in FIG. 3, transmits the light of the first wavelength band λ1 and blocks the light of the second wavelength band λ2. Having the second optical characteristic. Note that the vertical and horizontal axes in FIG. 3 indicate “transmittance” and “wavelength”, respectively.
　このように構成された格子プレート５に対して第１波長帯域λ１のパターン光Ｌ１が照射され、パターン光Ｌ１はそのまま格子プレート５を通過して物体Ｗに照射される。これによって、物体Ｗの表面にグレイコードが投影され、従来より周知の空間コード化法により物体Ｗの形状を測定可能となっている（第１形状測定工程）。一方、第２波長帯域λ２の照明光Ｌ２が格子プレート５に照射されると、照明光Ｌ２のうちパターン部材５２に照射された光はパターン部材５２で遮光され、残りは平板基材５１を透過して物体Ｗに照射される。このため、物体Ｗの表面には、上記正弦波格子パターン（図５中の符号Ｇ）に対応した格子画像が投影される。このように格子プレート５は特定の第２波長帯域λ２に対してのみ透過しない格子として機能する。 (4) The pattern light L1 of the first wavelength band λ1 is irradiated to the grating plate 5 configured as described above, and the pattern light L1 passes through the grating plate 5 and irradiates the object W as it is. As a result, the gray code is projected on the surface of the object W, and the shape of the object W can be measured by a conventionally known spatial coding method (first shape measurement step). On the other hand, when the illumination light L2 of the second wavelength band λ2 is applied to the grating plate 5, the light applied to the pattern member 52 of the illumination light L2 is blocked by the pattern member 52, and the rest is transmitted through the flat base material 51. Then, the object W is irradiated. For this reason, on the surface of the object W, a lattice image corresponding to the sine wave lattice pattern (reference G in FIG. 5) is projected. As described above, the grating plate 5 functions as a grating that does not transmit only the specific second wavelength band λ2.
　撮像部９は、モノクロの画像を取得するモノクロ撮像素子９１と、物体Ｗの像をモノクロ撮像素子９１の撮像面９１１（図５参照）に結像する結像レンズ９２とを有している。このため、図２の（ａ）欄に示すように、光源８１～８３を消灯させた状態で制御部１０からの投影指令に応じてプロジェクター７がパターン光Ｌ１を物体Ｗに向けて出射すると、上記したようにグレイコードが物体Ｗの表面に投影され、その物体Ｗをモノクロ撮像素子９１が撮像する。こうして撮像された画像が本発明の「パターン投影画像」の一例であり、その画像データがモノクロ撮像素子９１から制御部１０に転送され、空間コード化法により物体Ｗの形状を測定可能となっている（第１形状測定工程）。 The imaging unit 9 includes a monochrome imaging device 91 that acquires a monochrome image, and an imaging lens 92 that forms an image of the object W on an imaging surface 911 (see FIG. 5) of the monochrome imaging device 91. For this reason, as shown in column (a) of FIG. 2, when the projector 7 emits the pattern light L1 toward the object W in response to a projection command from the control unit 10 with the light sources 81 to 83 turned off, As described above, the gray code is projected on the surface of the object W, and the monochrome image sensor 91 images the object W. The image thus captured is an example of the “pattern projection image” of the present invention, and the image data is transferred from the monochrome image sensor 91 to the control unit 10, and the shape of the object W can be measured by the spatial coding method. (First shape measurement step).
　一方、プロジェクター７による投影を規制した状態で光源８１～８３を順次点灯すると、上記したように物体Ｗの表面に格子画像が投影される。このように格子画像が投影された物体Ｗを撮像部９は格子プレート５を介して撮像するため、モノクロ撮像素子９１に撮像された画像には、格子画像が投影された物体Ｗの像と正弦波格子パターンの像を重ねて生じるモワレ縞画像が含まれている。この画像データがモノクロ撮像素子９１から制御部１０に転送され、シャドーモワレ法により物体Ｗの形状を測定可能となっている（第２形状測定工程）。また、本実施形態は後で詳述するように位相シフトを伴うシャドーモアレ法を実行するために、光源８１～８３を順次互いに異なるタイミングで発光させることによって物体Ｗの表面で格子模様を移動させている。そして、このように移動する格子模様が撮像部９で撮像される。 On the other hand, when the light sources 81 to 83 are sequentially turned on in a state where the projection by the projector 7 is restricted, the lattice image is projected on the surface of the object W as described above. Since the image capturing unit 9 captures the object W on which the lattice image is projected in this way via the lattice plate 5, the image captured by the monochrome image sensor 91 includes the image of the object W on which the lattice image is projected and the sinusoidal image. A moire fringe image generated by superimposing images of the wave grating pattern is included. This image data is transferred from the monochrome image sensor 91 to the control unit 10, and the shape of the object W can be measured by the shadow moire method (second shape measurement step). In the present embodiment, the grid pattern is moved on the surface of the object W by sequentially causing the light sources 81 to 83 to emit light at different timings in order to execute the shadow moiré method with a phase shift as described in detail later. ing. Then, the image of the moving lattice pattern is captured by the imaging unit 9.
　制御部１０は、ＣＰＵ(Central Processing Unit)やＲＡＭ(Random Access
Memory)等で構成されたコンピュータを有している。そして、制御部１０は、上記したように装置各部の動作を制御してグレイコードが投影された物体Ｗの表面を撮像してパターン投影画像を取得する（第１形状測定工程）と、光源８１～８３の点灯切替に応じて物体Ｗの表面で格子模様を光源８１～８３の配列方向に移動させつつモワレ縞画像を取得する（第２形状測定工程）とを連続的に実行する。また、こうして得られた画像（＝パターン投影画像＋モワレ縞画像）に基づいて制御部１０は物体Ｗの三次元空間座標を確定する（座標確定工程）。このような第１形状測定工程、第２形状測定工程および座標確定工程の実行について図４および図５を参照しつつ説明する。 The control unit 10 includes a CPU (Central Processing Unit) and a RAM (Random Access Unit).
Memory) or the like. Then, the control unit 10 controls the operation of each unit of the apparatus as described above to capture an image of the surface of the object W on which the gray code is projected to obtain a pattern projection image (first shape measurement step). The moire fringe image is obtained while the lattice pattern is moved in the direction of arrangement of the light sources 81 to 83 on the surface of the object W in accordance with the switching of the lighting of the light sources 83 to 83 (second shape measuring step). Further, the control unit 10 determines the three-dimensional spatial coordinates of the object W based on the image (= pattern projection image + Moire fringe image) thus obtained (coordinate determination step). The execution of the first shape measurement step, the second shape measurement step, and the coordinate determination step will be described with reference to FIGS.
　図４は図１に示す形状測定装置による形状測定動作を示すフローチャートである。また、図５は形状測定動作を模試的に示す図である。形状測定装置１Ａでは、測定対象となる物体Ｗが保持部２に保持されると、第１形状測定工程（ステップＳ１）、第２形状測定工程（ステップＳ２）および座標確定工程（ステップＳ３）をこの順序で実行する。 FIG. 4 is a flowchart showing a shape measuring operation by the shape measuring apparatus shown in FIG. FIG. 5 is a diagram schematically illustrating the shape measuring operation. In the shape measuring apparatus 1A, when the object W to be measured is held by the holding unit 2, the first shape measuring step (Step S1), the second shape measuring step (Step S2), and the coordinate determination step (Step S3) are performed. Execute in this order.
　第１形状測定工程では、光源８１～８３を消灯させた状態のままプロジェクター７がグレイコードを含む第１波長帯域λ１のパターン光Ｌ１を物体Ｗに向けて出射し、格子プレート５を介して物体Ｗに照射する。これによって、物体Ｗの表面にグレイコードが投影される（ステップＳ１－１）。このとき、パターン光Ｌ１は波長帯域λ１の光であるため、正弦波格子パターンＧの影響を受けることなく、図５の（ａ）欄に示すように格子プレート５をそのまま通過して物体Ｗの表面に照射される。 In the first shape measurement step, the projector 7 emits the pattern light L1 of the first wavelength band λ1 including the gray code toward the object W while the light sources 81 to 83 are turned off, and outputs the object light via the grating plate 5. Irradiate W. Thus, the gray code is projected on the surface of the object W (step S1-1). At this time, since the pattern light L1 is light of the wavelength band λ1, it is not affected by the sine wave grating pattern G, and passes through the grating plate 5 as it is as shown in the column (a) of FIG. Irradiated on the surface.
　そして、従来より周知の空間コード化法、例えば電子通信学会論文誌１９８５年３月Ｖｏｌ．Ｊ６８－Ｄ　Ｎｏ．３の３６９～３７１頁に記載された空間コード化法により物体Ｗの点Ｐの三次元座標（Ｘ，Ｙ，Ｚ）を測定する。すなわち、パターン光Ｌ１では、複数の投影光が一定の広がりを持って物体Ｗに向けて照射されており、パターン光Ｌ１を細かい扇状領域（同図の（ａ）欄では、そのうちの一つにドットが付されて図示されている）に分割し、こうして形成された各空間をコード化する、つまり各空間に対して投影光コードを与える（ステップＳ１－２）。そして、物体Ｗの点ＰのＸ座標およびＹ座標について、投影されたモノクロ撮像素子９１の撮像面９１１上の座標Ｃ（ｘ，ｙ）から得られる、撮像部９から見た点Ｐの方向、つまり鉛直方向Ｚに対する角度θを算出する（ステップＳ１－３）。また、上記座標Ｃ（ｘ，ｙ）のグレイコードの明暗パターン（投影光コード）から扇状領域を特定し、当該扇状領域内の投影光の点Ｐへの照射方向、つまり鉛直方向Ｚに対する角度ψを算出する（ステップＳ１－４）。さらに、三角測量の原理により鉛直方向Ｚにおける点ＰのＺ軸座標を算出する（ステップＳ１－５）とともに、点ＰのＸ座標およびＹ座標を算出する（ステップＳ１－６）。こうして算出された点Ｐの三次元位置、つまり三次元座標Ｐ（Ｘ，Ｙ，Ｚ）は制御部１０のメモリに記憶される。なお、本実施形態では、三次元座標の原点は結像レンズ９２の主点Ｏに設定されている。 Then, conventionally known spatial coding methods, for example, IEICE Transactions, March 1985, Vol. J68-D No. The three-dimensional coordinates (X, Y, Z) of the point P of the object W are measured by the spatial coding method described on pages 369 to 371 of Jpn. That is, in the pattern light L1, a plurality of projection lights are radiated toward the object W with a certain spread, and the pattern light L1 is divided into a fine fan-shaped area (in the column (a) of FIG. Each space thus formed is encoded, that is, a projection light code is given to each space (step S1-2). Then, with respect to the X coordinate and the Y coordinate of the point P of the object W, the direction of the point P viewed from the imaging unit 9, which is obtained from the projected coordinates C (x, y) on the imaging surface 911 of the monochrome imaging device 91, That is, the angle θ with respect to the vertical direction Z is calculated (step S1-3). Further, a fan-shaped area is specified from the light-dark pattern (projection light code) of the gray code at the coordinates C (x, y), and the projection direction of the projection light in the fan-shaped area to the point P, that is, the angle に 対 す る with respect to the vertical direction Z Is calculated (step S1-4). Further, the Z-axis coordinates of the point P in the vertical direction Z are calculated based on the principle of triangulation (step S1-5), and the X and Y coordinates of the point P are calculated (step S1-6). The three-dimensional position of the point P thus calculated, that is, the three-dimensional coordinates P (X, Y, Z) is stored in the memory of the control unit 10. In the present embodiment, the origin of the three-dimensional coordinates is set to the principal point O of the imaging lens 92.
　こうして空間コード化法による物体Ｗの形状測定、つまり第１形状測定工程（ステップＳ１）が完了すると、位相シフトを伴うシャドーモアレ法、例えば特許文献１に記載の方法で物体Ｗの点Ｐの三次元座標（Ｘ，Ｙ，Ｚ）を測定する（第２形状測定工程：ステップＳ２）。すなわち、プロジェクター７からのパターン光Ｌ１の出射を停止する一方で、図５の（ｂ）欄に示すように光源８１が点灯されて第２波長帯域λ２の照明光Ｌ２が物体Ｗに向けて出射され、正弦波格子パターンＧに対応した格子画像が物体Ｗの表面に投影される（ステップＳ２－１）。そして、モノクロ撮像素子９１が格子プレート５を介して格子模様が投影された物体Ｗを撮像する。これは、ステップＳ２－２で全ての光源８１～８３について物体Ｗの撮像が完了したことを確認するまで、光源の発光のタイミングを異ならせながら物体Ｗの撮像が繰り返される。より具体的には、光源８１の消灯に続いて光源８２を点灯し、光源８１の点灯時と同様に格子プレート５を介して格子模様が投影された物体Ｗを撮像する。さらに、さらに、光源８２の消灯に続いて光源８３を点灯し、光源８１、８２の点灯時と同様に格子プレート５を介して格子模様が投影された物体Ｗを撮像する。 When the shape measurement of the object W by the space coding method, that is, the first shape measurement step (step S1) is completed, the third order of the point P of the object W is obtained by the shadow moire method with phase shift, for example, the method described in Patent Document 1. The original coordinates (X, Y, Z) are measured (second shape measuring step: step S2). In other words, while the emission of the pattern light L1 from the projector 7 is stopped, the light source 81 is turned on and the illumination light L2 of the second wavelength band λ2 is emitted toward the object W as shown in a section (b) of FIG. Then, a lattice image corresponding to the sinusoidal lattice pattern G is projected on the surface of the object W (step S2-1). Then, the monochrome image sensor 91 captures an image of the object W on which the lattice pattern is projected via the lattice plate 5. This means that the imaging of the object W is repeated while changing the light emission timing of the light sources until it is confirmed in step S2-2 that the imaging of the object W has been completed for all the light sources 81 to 83. More specifically, the light source 82 is turned on after the light source 81 is turned off, and the object W on which the grid pattern is projected via the grid plate 5 is imaged in the same manner as when the light source 81 is turned on. Further, after the light source 82 is turned off, the light source 83 is turned on, and the object W on which the grid pattern is projected via the grid plate 5 is imaged in the same manner as when the light sources 81 and 82 are turned on.
　そして、全ての光源８１～８３について物体Ｗの撮像が完了したことを確認する（ステップＳ２－２で「ＹＥＳ」）と、物体Ｗの点Ｐ（Ｘ，Ｙ，Ｚ）についてモノクロ撮像素子９１の撮像面９１１上の座標Ｃ（ｘ，ｙ）から位相値φ（ｘ，ｙ）を算出する（ステップＳ２－３）。同（ｂ）欄では、正弦波格子パターンＧの格子面と撮像部９の光軸ＯＡとの交点を原点としている。 Then, it is confirmed that the imaging of the object W has been completed for all the light sources 81 to 83 (“YES” in step S2-2), and the point P (X, Y, Z) of the object W The phase value φ (x, y) is calculated from the coordinates C (x, y) on the imaging surface 911 (step S2-3). In the column (b), the intersection point between the lattice plane of the sine wave lattice pattern G and the optical axis OA of the imaging unit 9 is set as the origin.
　ここで、位相値φ（ｘ，ｙ）は、測定対象となる物体Ｗの形状が連続的に変化している場合や段差部位Ｗａが正弦波格子パターンＧを構成するパターン部材５２の１ピッチ以内となっている場合には、単純に２πを加算すればよいが、１ピッチ以上の段差を持つ場合には、位相の飛びが２πの何倍に相当する、つまり縞次数ｎ（ｘ、ｙ）を求める必要がある。 Here, the phase value φ (x, y) is determined when the shape of the object W to be measured is continuously changing or when the stepped portion Wa is within one pitch of the pattern member 52 constituting the sine wave grating pattern G. In this case, 2π may be simply added. However, when there is a step of one pitch or more, the phase jump corresponds to a multiple of 2π, that is, the stripe order n (x, y) Need to ask.
　そこで、本実施形態では、座標確定工程（ステップＳ３）を実行する。この座標確定工程では、第１形状測定工程（ステップＳ１）で求めた点Ｐの三次元座標（Ｘ，Ｙ，Ｚ）に基づいて縞次数ｎ（ｘ、ｙ）を決定する（ステップＳ３－１）。そして、その縞次数ｎ（ｘ、ｙ）によりアンラッピング処理を行い、それによって算出された三次元座標（Ｘ，Ｙ，Ｚ）を点Ｐの三次元位置とする（ステップＳ３－２）。 Therefore, in the present embodiment, a coordinate determination step (step S3) is executed. In this coordinate determination step, the stripe order n (x, y) is determined based on the three-dimensional coordinates (X, Y, Z) of the point P obtained in the first shape measurement step (step S1) (step S3-1). ). Then, an unwrapping process is performed using the stripe order n (x, y), and the three-dimensional coordinates (X, Y, Z) calculated thereby are set as the three-dimensional position of the point P (step S3-2).
　以上のように、本実施形態によれば、次のような作用効果が得られる。物体Ｗの形状が連続的に変化している物体Ｗや段差部位Ｗａが存在するもののパターン部材５２の１ピッチ以内である物体Ｗについては、シャドーモアレ法に位相シフトを組み合わせることで高い精度で物体Ｗの形状測定を行うことができる。ここで、１ピッチを超える段差部位Ｗａが物体Ｗに存在すると、位相のラップ（飛び）が生じるが、本実施形態では空間コード化法により得られる位置情報に基づいてアンラッピング処理を実行している。このため、段差部位Ｗａを有さない物体Ｗはもちろんのこと、段差部位Ｗａを有する物体Ｗについても形状測定を高精度に行うことができる。 As described above, according to the present embodiment, the following operational effects can be obtained. For the object W in which the shape of the object W is continuously changing or the object W having the stepped portion Wa but within one pitch of the pattern member 52, the object W can be obtained with high accuracy by combining the phase shift with the shadow moire method. W shape measurement can be performed. Here, if a step portion Wa exceeding one pitch exists in the object W, a phase wrap (jump) occurs. In the present embodiment, the unwrapping process is executed based on the position information obtained by the spatial coding method. I have. Therefore, the shape measurement of the object W having the stepped portion Wa as well as the object W having no stepped portion Wa can be performed with high accuracy.
　また、第２形状測定工程のみを用いて物体Ｗの形状測定を行うためには、段差部位Ｗａに適合する格子ピッチ（隣り合うパターン部材５２のピッチ）を有する格子プレート５に交換して形状測定を行う必要がある。これに対し、本実施形態では、上記したようにパターン画像に基づく空間コード化法を組み合わせることで格子プレート５を変更することなく、物体Ｗの形状を高精度に測定することができる。 Further, in order to measure the shape of the object W using only the second shape measurement step, the shape is measured by replacing the grating plate 5 with a grating pitch (pitch between the adjacent pattern members 52) suitable for the stepped portion Wa. Need to do. On the other hand, in the present embodiment, the shape of the object W can be measured with high accuracy without changing the grid plate 5 by combining the spatial coding method based on the pattern image as described above.
　図６は本発明に係る物体の形状測定装置の第２実施形態を示す図である。この第２実施形態に係る形状測定装置１Ｂが第１実施形態と大きく相違する点は、コンベア駆動部２１によりコンベア２２を循環移動させることで物体Ｗを水平方向Ｘに搬送させながら物体Ｗの形状測定を行っている点と、第２形状測定工程において光源８１～８３を切り替えて位相シフトを行う代わりに物体Ｗの移動により位相シフトを行っている点であり、その他の構成は基本的に第１実施形態と同様である。この第２実施形態においても、位相シフトを伴うシャドーモアレ法と空間コード化法とを組み合わせているため、段差部位Ｗａの有無を問わず、物体Ｗの形状測定を高精度に行うことができる。なお、本実施形態では、コンベア２２が本発明の「移動部」の一例に相当している。 FIG. 6 is a view showing a second embodiment of the object shape measuring apparatus according to the present invention. The point that the shape measuring apparatus 1B according to the second embodiment is significantly different from the first embodiment is that the shape of the object W is conveyed in the horizontal direction X by circulating the conveyor 22 by the conveyor driving unit 21. The point is that the measurement is performed and the phase shift is performed by moving the object W instead of performing the phase shift by switching the light sources 81 to 83 in the second shape measurement step. This is the same as in the first embodiment. Also in the second embodiment, since the shadow moiré method with a phase shift and the space coding method are combined, the shape measurement of the object W can be performed with high accuracy regardless of the presence or absence of the stepped portion Wa. In the present embodiment, the conveyor 22 corresponds to an example of the “moving unit” of the present invention.
　また、このように構成された形状測定装置１Ｂについては、例えば図７に示すように物体Ｗに傷等の欠陥が無いかどうかを調べる、いわゆる外観検査装置に組み込んでもよい。外観検査装置の一例としては、例えば特開２０１７－２２７６２１号公報に記載されたものがある。この外観検査装置では、鍛造や鋳造などにより製造される金属製品（本発明の「物体」の一例に相当）における欠陥の有無を調べるために、金属製品の外観検査を行って金属製品のうち形状欠陥が含まれる欠陥領域を抽出する。そこで、例えば図７に示すように、外観検査装置１００において、物体（金属製品）Ｗをコンベアなどの搬送機構１１０により所定方向に搬送しながら外観検査部１２０による外観検査および形状測定部１３０による欠陥領域の形状測定を行うように構成してもよい。以下、図７を参照しつつ外観検査装置１００の構成および動作について説明する。 The shape measuring device 1B configured as described above may be incorporated in a so-called visual inspection device that checks whether or not the object W has a defect such as a scratch as shown in FIG. As an example of the appearance inspection apparatus, there is one described in, for example, JP-A-2017-227621. This appearance inspection device performs an appearance inspection of a metal product in order to examine the presence or absence of a defect in a metal product (corresponding to an example of the “object” of the present invention) manufactured by forging, casting, or the like, and performs a shape inspection of the metal product. A defect area including a defect is extracted. Therefore, as shown in FIG. 7, for example, in the visual inspection device 100, the visual inspection unit 120 performs the visual inspection while the object (metal product) W is transported in a predetermined direction by the transport mechanism 110 such as a conveyor, and the defect is detected by the shape measuring unit 130. You may comprise so that the shape measurement of an area | region may be performed. Hereinafter, the configuration and operation of the visual inspection device 100 will be described with reference to FIG.
　図７は本発明に係る形状測定装置の第３実施形態を装備する外観検査装置の一例を模式的に示す図である。この外観検査装置１００では、外観検査の対象となる物体Ｗが搬送機構１１０により水平方向に搬送される。また、物体Ｗの搬送経路に沿って外観検査部１２０と形状測定部１３０とが並設されている。外観検査部１２０は、物体Ｗの搬送方向において形状測定部１３０の上流側（同図における左手側）に配置されている。 FIG. 7 is a view schematically showing an example of a visual inspection device equipped with a third embodiment of the shape measuring device according to the present invention. In the appearance inspection apparatus 100, the object W to be subjected to the appearance inspection is transported in the horizontal direction by the transport mechanism 110. Further, the appearance inspection unit 120 and the shape measurement unit 130 are provided side by side along the transport path of the object W. The appearance inspection unit 120 is arranged on the upstream side of the shape measurement unit 130 in the transport direction of the object W (on the left hand side in the drawing).
　外観検査部１２０には、搬送機構１１０の鉛直上方に撮像カメラ１２１が配置されている。また、搬送機構１１０の斜め上方において、２つの照明器具１２２、１２３が撮像カメラ１２１を挟み込むように配置されている。外観検査装置１００では、予め良品と判別された物体Ｗを撮像カメラ１２１により撮像して取得される参照画像のデータが記憶されている。そして、検査対象となる物体Ｗが搬送機構１１０により外観検査部１２０に搬送されてくると、撮像カメラ１２１により物体Ｗを撮像し、その撮像画像と参照画像とを比較して欠陥の有無を判定する。 撮 像 In the appearance inspection unit 120, an imaging camera 121 is disposed vertically above the transport mechanism 110. Further, two lighting fixtures 122 and 123 are arranged diagonally above the transport mechanism 110 so as to sandwich the imaging camera 121. In the appearance inspection apparatus 100, data of a reference image acquired by imaging the object W determined in advance as a non-defective product with the imaging camera 121 is stored. When the object W to be inspected is transported by the transport mechanism 110 to the appearance inspection unit 120, the image of the object W is captured by the imaging camera 121, and the captured image is compared with the reference image to determine the presence or absence of a defect. I do.
　一方、形状測定部１３０は物体Ｗの搬送方向Ｘにおいて外観検査部１２０の下流側に設けられている。形状測定部１３０には、上記実施形態と同様に測定ヘッド４および格子プレート５により物体Ｗの形状を測定する形状測定ユニット１３１が搬送機構１１０の斜め上方に２組設けられている。各形状測定ユニット１３１に対して図示を省略するロボットアームが接続されており、搬送機構１１０により外観検査部１２０から搬送されてくる物体Ｗに対して任意の姿勢で各形状測定ユニット１３１による形状測定が実行可能となっている。各形状測定ユニット１３１は、外観検査部１２０により見つけ出された欠陥領域と対向するように姿勢制御された状態で、上記実施形態と同様に第１形状測定工程、第２形状測定工程および座標確定工程を実行して欠陥領域の形状を詳細に測定し、その測定結果を出力する。 On the other hand, the shape measuring unit 130 is provided downstream of the visual inspection unit 120 in the transport direction X of the object W. In the shape measuring unit 130, two sets of shape measuring units 131 for measuring the shape of the object W with the measuring head 4 and the grid plate 5 are provided diagonally above the transport mechanism 110 as in the above embodiment. A robot arm (not shown) is connected to each shape measuring unit 131, and the shape is measured by the shape measuring unit 131 in an arbitrary posture with respect to the object W conveyed from the visual inspection unit 120 by the conveying mechanism 110. Is executable. Each of the shape measuring units 131 is in a state where the posture is controlled so as to face the defect area found by the appearance inspection unit 120, and the first shape measuring step, the second shape measuring step, and the coordinate determination are performed similarly to the above embodiment. The process is executed to measure the shape of the defect area in detail, and the measurement result is output.
　このように図７に示す外観検査装置１００によれば、物体Ｗの表面に存在する欠陥領域を見つけ出し、その詳細な形状測定を行うことが可能となっており、物体Ｗの検査を高精度に行うことができる。なお、図７に示す外観検査装置１００では、外観検査部１２０で検査された時の姿勢のまま物体Ｗを搬送機構１１０により形状測定部１３０に搬送しているが、外観検査部１２０と形状測定部１３０との間に物体Ｗの姿勢を調整する、例えば物体Ｗを反転させる反転機構（図示省略）を設けてもよく、これによって形状測定部１３０により測定可能となる範囲を広げることができる。 As described above, according to the appearance inspection apparatus 100 illustrated in FIG. 7, it is possible to find out a defect region existing on the surface of the object W and perform detailed shape measurement thereof, and to inspect the object W with high accuracy. It can be carried out. In the appearance inspection apparatus 100 shown in FIG. 7, the object W is transported to the shape measurement unit 130 by the transportation mechanism 110 in the posture when inspected by the appearance inspection unit 120. A reversing mechanism (not shown) for adjusting the posture of the object W, for example, for reversing the object W, may be provided between the unit 130 and the unit 130, whereby the range that can be measured by the shape measuring unit 130 can be expanded.
　なお、本発明は上記した実施形態に限定されるものではなく、その趣旨を逸脱しない限りにおいて上述したもの以外に種々の変更を行うことが可能である。例えば本実施形態では、モノクロ撮像素子９１を用いて第１形状測定工程（ステップＳ１）と第２形状測定工程（ステップＳ２）とをこの順序で実行しているが、これらの順序を逆転させてもよい。また、モノクロ撮像素子９１の代わりに、カラーＣＣＤやカラーＣＭＯＳなどのカラー撮像素子を用いることで第１形状測定工程（ステップＳ１）と第２形状測定工程（ステップＳ２）とを同時に行ってもよく、この場合、形状測定に要する時間を短縮することができる。 The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention. For example, in the present embodiment, the first shape measurement step (step S1) and the second shape measurement step (step S2) are performed in this order by using the monochrome image sensor 91, but the order is reversed. Is also good. Further, the first shape measuring step (step S1) and the second shape measuring step (step S2) may be performed simultaneously by using a color image sensor such as a color CCD or a color CMOS instead of the monochrome image sensor 91. In this case, the time required for shape measurement can be reduced.
　また、第１形状測定工程（ステップＳ１）と第２形状測定工程（ステップＳ２）とを同時に行うために、モノクロ撮像素子９１の代わりに、図８に示すように、２つのモノクロ撮像素子９３、９４と、ダイクロイックミラーなどの色分離素子９５とを設けてもよい（第４実施形態）。 In addition, in order to simultaneously perform the first shape measurement step (step S1) and the second shape measurement step (step S2), instead of the monochrome image sensor 91, as shown in FIG. 94 and a color separation element 95 such as a dichroic mirror may be provided (fourth embodiment).
　図８は本発明に係る物体の形状測定装置の第４実施形態を示す図である。この第４実施形態では、第１形状測定工程（ステップＳ１）と第２形状測定工程（ステップＳ２）とを同時に行う際には、第１波長帯域λ１の光と第２波長帯域λ２の光と撮像部９に入射されるが、本実施形態では結像レンズ９２の出射側に色分離素子９５が配置されている。この色分離素子９５は第１波長帯域λ１の光を反射して第１モノクロ撮像素子９３に導光するとともに第２波長帯域λ２の光をそのまま透過させて第２モノクロ撮像素子９４に導光する。したがって、第１モノクロ撮像素子９３で第１波長帯域の光を受光して第１形状測定工程（ステップＳ１）と第２モノクロ撮像素子９４で第２波長帯域の光を受光して第２形状測定工程（ステップＳ２）とを同時に実行可能となっており、形状測定に要する時間を短縮することができる。 FIG. 8 is a view showing a fourth embodiment of the object shape measuring apparatus according to the present invention. In the fourth embodiment, when the first shape measurement step (step S1) and the second shape measurement step (step S2) are performed simultaneously, light of the first wavelength band λ1 and light of the second wavelength band λ2 are not used. Although the light is incident on the imaging unit 9, in the present embodiment, a color separation element 95 is arranged on the emission side of the imaging lens 92. The color separation element 95 reflects the light in the first wavelength band λ1 to guide the light to the first monochrome image sensor 93 and transmits the light in the second wavelength band λ2 as it is to guide the light to the second monochrome image sensor 94. . Therefore, the first monochrome image sensor 93 receives light in the first wavelength band and the first shape measurement step (step S1), and the second monochrome image sensor 94 receives light in the second wavelength band and performs second shape measurement. The step (step S2) can be performed simultaneously, and the time required for shape measurement can be reduced.
　また、上記実施形態では、第２形状測定工程（ステップＳ２）を実行するために、３つの光源８１～８３として点光源を用いているが、線光源を用いてもよい。また、光源の個数は「３」に限定されるものではなく、４以上であってもよい。 Also, in the above embodiment, point light sources are used as the three light sources 81 to 83 in order to execute the second shape measurement step (step S2), but line light sources may be used. Further, the number of light sources is not limited to “3”, and may be four or more.
　また、第２形状測定工程（ステップＳ２）では位相シフトを併用しているが、位相シフトの併用は形状測定の精度を高める上で好適であるが、本発明の技術的特徴のひとつである空間コード化法との組み合わせにとって必須構成ではなく、あくまで任意構成である。
　以上、特定の実施例に沿って発明を説明したが、この説明は限定的な意味で解釈されることを意図したものではない。発明の説明を参照すれば、本発明のその他の実施形態と同様に、開示された実施形態の様々な変形例が、この技術に精通した者に明らかとなるであろう。故に、添付の特許請求の範囲は、発明の真の範囲を逸脱しない範囲内で、当該変形例または実施形態を含むものと考えられる。 Further, in the second shape measurement step (step S2), the phase shift is used in combination. The use of the phase shift is suitable for increasing the accuracy of the shape measurement, but the space is one of the technical features of the present invention. It is not an indispensable configuration for the combination with the coding method, but an optional configuration.
Although the invention has been described with reference to particular embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications and embodiments as do not depart from the true scope of the invention.
　この発明は、物体の形状を非接触で測定する形状測定技術全般に適用することができる。 The present invention can be applied to all shape measurement techniques for measuring the shape of an object in a non-contact manner.
　１Ａ，１Ｂ…形状測定装置
　５…格子プレート
　７…プロジェクター（投影部）
　８…光源部
　９…撮像部
　１０…制御部
　２２…コンベア（移動部）
　５１…平板基材
　５２…パターン部材
　８１～８３…光源
　９１…モノクロ撮像素子
　９３…第１モノクロ撮像素子
　９４…第２モノクロ撮像素子
　９５…色分離素子
　１３１…形状測定ユニット（形状測定装置）
　Ｇ…正弦波格子パターン
　Ｌ１…パターン光
　Ｌ２…照明光
　λ１…第１波長帯域
　λ２…第２波長帯域
　Ｗ…物体
　Ｗａ…段差部位
　Ｘ…水平方向（第２の方向）
　Ｚ…鉛直方向（第１の方向）
  1A, 1B: Shape measuring device 5: Lattice plate 7: Projector (projection unit)
8 light source unit 9 imaging unit 10 control unit 22 conveyor (moving unit)
Reference Signs List 51: Flat substrate 52: Pattern member 81 to 83: Light source 91: Monochrome imaging device 93: First monochrome imaging device 94: Second monochrome imaging device 95: Color separation device 131: Shape measuring unit (shape measuring device)
G: sine wave grating pattern L1: pattern light L2: illumination light λ1: first wavelength band λ2: second wavelength band W: object Wa: stepped portion X: horizontal direction (second direction)
Z: Vertical direction (first direction)

Claims (8)

  1. 　物体の形状を非接触で測定する形状測定装置であって、
    　前記物体から第１の方向に離間して配置され、空間コード化法に基づいて設定されるパターン画像を含む第１波長帯域のパターン光を前記物体に向けて出射する投影部と、
    　前記物体から前記第１の方向に離間して配置され、前記第１波長帯域と異なる第２波長帯域の照明光を前記物体に向けて出射する光源部と、
    　前記第１の方向において前記物体と前記光源部および前記投影部との間に配置され、前記第１波長帯域の光については全部を透過させ、前記第２波長帯域の光については一部を遮光して格子パターンを形成する格子プレートと、
    　前記格子プレートを介して前記物体を撮像可能に設けられ、前記パターン光の照射により前記パターン画像が投影された前記物体を撮像してパターン投影画像を取得し、前記照明光の照射により前記格子パターンに対応する格子模様が投影された前記物体を撮像することで前記物体の像と前記格子パターンの像を重ねて生じるモワレ縞画像を取得する撮像部と、
    　前記撮像部により撮像された前記モワレ縞画像および前記パターン投影画像に基づいて前記物体の三次元空間座標を求める制御部と
    を備えることを特徴とする形状測定装置。     A shape measuring device for measuring the shape of an object in a non-contact manner,
    A projection unit that is arranged apart from the object in a first direction and emits pattern light of a first wavelength band including a pattern image set based on a spatial coding method toward the object;
    A light source unit that is arranged apart from the object in the first direction and emits illumination light of a second wavelength band different from the first wavelength band toward the object;
    It is arranged between the object and the light source unit and the projection unit in the first direction, transmits all light in the first wavelength band, and partially blocks light in the second wavelength band. A grid plate to form a grid pattern
    The object is provided so as to be able to image the object through the lattice plate, the object on which the pattern image is projected by the irradiation of the pattern light is imaged to obtain a pattern projection image, and the lattice pattern is irradiated by the illumination light. An imaging unit that acquires a moiré fringe image generated by superimposing an image of the object and an image of the lattice pattern by imaging the object on which the lattice pattern corresponding to is projected,
    A shape measurement device, comprising: a control unit that obtains three-dimensional spatial coordinates of the object based on the Moire fringe image captured by the imaging unit and the pattern projection image.
  2. 　請求項１に記載の形状測定装置であって、
    　前記格子プレートは、
    　前記第１波長帯域および前記第２波長帯域の光を透過させる第１の光学特性を有する平板基材と、
    　前記第１波長帯域の光を透過させる一方で前記第２波長帯域の光を遮光する第２の光学特性を有し、前記平板基材の一方主面上で互いに離間して設けられて前記格子パターンを構成する複数のパターン部材と
    を有する形状測定装置。     The shape measuring device according to claim 1,
    The grid plate is
    A flat substrate having first optical characteristics for transmitting light in the first wavelength band and the second wavelength band;
    The grating has a second optical property of transmitting the light of the first wavelength band and shielding the light of the second wavelength band, and is provided apart from each other on one main surface of the flat substrate. A shape measuring device having a plurality of pattern members constituting a pattern.
  3. 　請求項１または２に記載の形状測定装置であって、
    　前記撮像部はモノクロの画像を取得するモノクロ撮像素子で前記物体を撮像し、
    　前記制御部は、前記パターン光および前記照明光を個別に出射させるとともに、前記パターン光の出射に対応して前記撮像部により前記パターン投影画像を取得する第１形状測定処理を実行し、前記照明光の出射に対応して前記撮像部により前記モワレ縞画像を取得する第２形状測定処理を実行する形状測定装置。     It is a shape measuring device according to claim 1 or 2,
    The imaging unit images the object with a monochrome imaging device that acquires a monochrome image,
    The control unit causes the pattern light and the illumination light to be separately emitted, and executes a first shape measurement process of acquiring the pattern projection image by the imaging unit in response to the emission of the pattern light. A shape measurement device that performs a second shape measurement process of acquiring the Moire fringe image by the imaging unit in response to emission of light.
  4. 　請求項１または２に記載の形状測定装置であって、
    　前記撮像部はカラーの画像を取得するカラー撮像素子で前記物体を撮像し、
    　前記制御部は、前記パターン光および前記照明光を同時に出射させるとともに、前記撮像部により前記パターン投影画像を取得する第１形状測定処理と前記撮像部により前記モワレ縞画像を取得する第２形状測定処理とを同時に実行する形状測定装置。     It is a shape measuring device according to claim 1 or 2,
    The imaging unit images the object with a color imaging device that acquires a color image,
    The control unit simultaneously emits the pattern light and the illumination light, and obtains the pattern projection image by the imaging unit in a first shape measurement process and obtains the Moire fringe image by the imaging unit in a second shape measurement process A shape measuring device that performs processing simultaneously.
  5. 　請求項１または２に記載の形状測定装置であって、
    　前記撮像部は、入射してくる光を前記第１波長帯域の光と前記第２波長帯域の光とに分離する色分離素子と、前記色分離素子により分離された前記第１波長帯域の光を受光して前記物体を撮像する第１モノクロ撮像素子と、前記色分離素子により分離された前記第２波長帯域の光を受光して前記物体を撮像する第２モノクロ撮像素子とを有し、
    　前記制御部は、前記パターン光および前記照明光を同時に出射させるとともに、前記第１モノクロ撮像素子により前記パターン投影画像を取得する第１形状測定処理と、前記第２モノクロ撮像素子により前記モワレ縞画像を取得する第２形状測定処理とを同時に実行する形状測定装置。     It is a shape measuring device according to claim 1 or 2,
    A color separation element for separating incident light into light of the first wavelength band and light of the second wavelength band; and light of the first wavelength band separated by the color separation element. A first monochrome image sensor that receives light and images the object, and a second monochrome image sensor that receives light in the second wavelength band separated by the color separation element and images the object,
    The control unit simultaneously emits the pattern light and the illumination light, and obtains the pattern projection image by the first monochrome image sensor. The first shape measurement process, and the moire fringe image by the second monochrome image sensor. A shape measurement device that simultaneously executes a second shape measurement process for acquiring a shape.
  6. 　請求項３ないし５のいずれか一項に記載の形状測定装置であって、
    　前記光源部では、照明光を発光する光源が３つ以上互いに離間して一列に配列され、
    　前記制御部は、
    　前記第２形状測定処理において前記３つ以上の光源を互いに異なるタイミングで発光させることで前記物体の表面で前記格子模様を移動させて位相を変化させ、
    　前記撮像部により撮像された前記パターン投影画像に基づいて前記物体の位置情報を取得し、前記位置情報に基づいて前記位相にアンラッピング処理を施して前記物体の三次元空間座標を確定する形状測定装置。     It is a shape measuring device according to any one of claims 3 to 5,
    In the light source unit, three or more light sources that emit illumination light are arranged in a line separated from each other,
    The control unit includes:
    In the second shape measurement process, the three or more light sources emit light at different timings to move the lattice pattern on the surface of the object to change the phase,
    Shape measurement for acquiring position information of the object based on the pattern projection image captured by the imaging unit, performing unwrapping processing on the phase based on the position information, and determining three-dimensional spatial coordinates of the object. apparatus.
  7. 　請求項３ないし５のいずれか一項に記載の形状測定装置であって、
    　前記第１の方向と異なる第２の方向に前記物体を移動させる移動部をさらに備え、
    　前記制御部は、
    　前記第２形状測定処理において前記第２の方向への前記物体の移動により前記物体の表面で前記格子模様を移動させて位相を変化させ、
    　前記撮像部により撮像された前記パターン投影画像に基づいて前記物体の位置情報を取得し、前記位置情報に基づいて前記位相にアンラッピング処理を施して前記物体の三次元空間座標を確定する形状測定装置。     It is a shape measuring device according to any one of claims 3 to 5,
    A moving unit that moves the object in a second direction different from the first direction,
    The control unit includes:
    Moving the grid pattern on the surface of the object by moving the object in the second direction in the second shape measurement process to change the phase;
    Shape measurement for acquiring position information of the object based on the pattern projection image captured by the imaging unit, performing unwrapping processing on the phase based on the position information, and determining three-dimensional spatial coordinates of the object. apparatus.
  8. 　物体の形状を非接触で測定する形状測定方法であって、
    　空間コード化法に基づいて設定されるパターン画像を含む第１波長帯域のパターン光を前記物体の表面に照射して前記パターン画像を投影するとともに、前記パターン画像が投影された前記物体を撮像してパターン投影画像を取得する第１形状測定工程と、
    　前記第１波長帯域と異なる第２波長帯域の照明光を格子パターンを介して前記物体の表面に照射して格子模様を投影するとともに、前記格子模様が投影された前記物体を撮像して前記物体の像と前記格子パターンの像を重ねて生じるモワレ縞画像を取得する第２形状測定工程と、
    　前記モワレ縞画像および前記パターン投影画像に基づいて前記物体の三次元空間座標を求める座標確定工程と
    を備えることを特徴とする形状測定方法。     A shape measuring method for measuring the shape of an object in a non-contact manner,
    While projecting the pattern image by irradiating the surface of the object with pattern light of a first wavelength band including a pattern image set based on a space coding method, imaging the object on which the pattern image is projected A first shape measuring step of obtaining a pattern projection image by
    Irradiating illumination light of a second wavelength band different from the first wavelength band on the surface of the object via a lattice pattern to project a lattice pattern, and imaging the object on which the lattice pattern is projected to form the object A second shape measurement step of obtaining a moire fringe image generated by superimposing the image of the lattice pattern and the image of
    A coordinate determination step of obtaining three-dimensional spatial coordinates of the object based on the Moire fringe image and the pattern projection image.
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JP3921432B2 (en) 2002-09-13 2007-05-30 株式会社リコー Shape measuring apparatus and shape measuring method using moire optical system
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JP2018044960A (en) * 2017-12-25 2018-03-22 株式会社キーエンス Three-dimensional image processing device, three-dimensional image processing head unit, three-dimensional image processing method, three-dimensional image processing program and computer readable recording medium as well as recording instrument

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* Cited by examiner, † Cited by third party
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