JP6554342B2 - Measuring system and measuring method - Google Patents

Description

  The present invention relates to a measurement system and a measurement method for measuring three-dimensional coordinates of an object to be measured.

  In recent years, research related to computer vision has been activated, and three-dimensional information input systems for objects using imaging devices are becoming familiar. Among these types of techniques, a light cutting method is widely known as a method for inputting a three-dimensional shape of an object using a camera as an imaging device.

  For example, Patent Document 1 below discloses a distance measuring device using a light cutting method. This distance measuring device images the reflected light (bright line) of slit light on the surface of an object (object to be measured) with a CCD camera, and determines the slit light emission direction, the position of the light source and the position of the CCD camera with the object. Measure the distance between.

JP 2002-156209 A

  On the other hand, in order to efficiently measure the shape or the like of the object to be measured, a method of simultaneously irradiating the object to be measured with a plurality of slit laser beams has been studied. However, when the object to be measured is irradiated with a plurality of slit lights, it is necessary to specify from which direction the slit laser light is projected. When the shape of the object to be measured is complicated, as in the case where the bright line appearing on the object to be measured and the slit laser light appearing on a portion other than the object to be measured are shifted in the captured image, the object to be measured and the object to be measured There are a plurality of repetitive patterns of bright lines that are discontinuous with parts other than the measurement object in the captured image. In such a case, since it is difficult to specify the slit laser beam corresponding to each of the plurality of bright lines, the distance to each bright line cannot be measured. As a result, three-dimensional coordinates of the object to be measured can not be measured.

  Therefore, the present invention has been made in view of these points, and an object thereof is to provide a measurement system and a measurement method capable of measuring the three-dimensional coordinates of the object to be measured with higher accuracy.

  In the first aspect of the present invention, a first irradiating means for irradiating the object to be measured with a plurality of slit laser beams, and the first irradiating means irradiates the object to be measured with the plurality of slit laser beams. And irradiating the plurality of dot laser beams having a predetermined positional relationship with each of the plurality of slit laser beams onto the object to be measured, and the plurality of slit laser beams. Imaging means for capturing a plurality of bright lines appearing on the surface of the object to be measured and a plurality of bright spots appearing on the surface by irradiating the plurality of dot laser beams to generate a captured image And the reference image indicating the predetermined positional relationship between the plurality of bright lines and the plurality of bright lines and the correspondence image between the plurality of bright lines of the captured image and the plurality of slit laser beams. Special to identify A measurement system comprising: means; and acquisition means for acquiring three-dimensional coordinates of the plurality of bright lines based on the two-dimensional coordinates of the plurality of bright lines in the captured image and the correspondence relationship specified by the specifying means. I will provide a.

  The first irradiation unit and the second irradiation unit may be located on the same straight line in the slit direction, which is the longitudinal direction of the slit that irradiates the slit laser beam.

  Further, the first irradiation unit and the second irradiation unit are positioned apart from each other by a predetermined distance in a direction other than the slit direction, and the measurement system is an irradiation position of the slit laser beam on the object to be measured; It is good also as providing the light reflection means for adjusting the irradiation position to the said to-be-measured object of the said dot laser beam.

  In addition, the irradiation direction of the plurality of slit laser beams to the object to be measured is a direction intersecting each other, and the specifying unit specifies the irradiation direction of the slit laser beams corresponding to each of the plurality of bright lines. It is good as well.

  In addition, the second irradiation unit may irradiate the plurality of dot laser beams so that each of the plurality of bright lines has a different bright spot adjacent state.

  Further, the specification unit may extract a unit area including one point of the bright line of the captured image and a periphery of the one point, and determine a degree of correlation of the reference image with the unit area.

  The object to be measured is a tubular body, and the imaging means images the plurality of bright lines and bright spots appearing on the surface of the tubular body from the direction of the line of sight intersecting the irradiation direction of the first irradiation means. It is good as well.

  Further, the acquisition means may acquire three-dimensional coordinates of a cross-sectional shape of the tubular body in which the arc-shaped bright line is a part.

  The cross-sectional shape may be an elliptical shape, and the acquiring unit may acquire a minor axis of the elliptical shape of the cross-sectional shape and set the minor axis as an outer diameter of the tubular body.

  Further, the acquisition unit may acquire a center line of the tubular body based on a plurality of cross-sectional shapes of the tubular body each of which is a part of the plurality of bright lines.

  Further, the acquisition unit may acquire a direction vector of a center line of the tubular body based on three-dimensional coordinates of points on the plurality of bright lines.

  In the second aspect of the present invention, the step of irradiating the object to be measured with a plurality of slit laser beams and the plurality of slit lasers when irradiating the object to be measured with the plurality of slit laser beams. The step of irradiating the object with a plurality of dot laser beams in the form of dots having a predetermined positional relationship with each of the light, and the irradiation of the plurality of slit laser beams appear on the surface of the object Imaging a plurality of bright lines and a plurality of bright points appearing on the surface by being irradiated with the plurality of dot laser beams to generate a picked-up image; the picked-up image; the plurality of bright lines and bright lines; Identifying a correspondence between the plurality of bright lines of the captured image and the plurality of slit laser beams by comparing with a reference image indicating a predetermined positional relationship of points; And two-dimensional coordinates of said plurality of bright lines that, based on the identified the correspondence relation, and a step of acquiring the three-dimensional coordinates of the plurality of emission lines, to provide a measurement method.

  According to the present invention, there is an effect that the three-dimensional coordinates of the object to be measured can be measured with higher accuracy.

It is a block diagram showing an example of composition of measuring system S concerning one embodiment of the present invention. It is a figure which shows an example of the irradiation state of slit laser beam with respect to a to-be-measured object. It is a schematic diagram for demonstrating an example of a structure of the slit laser irradiation apparatus 2 and the dot laser irradiation apparatus 3. FIG. It is a figure for demonstrating the positional relationship of slit laser beam and dot laser beam. It is a figure which shows an example of a captured image. It is a figure which shows an example of a reference | standard image. It is a figure for demonstrating the point of contrast object in a captured image. It is a schematic diagram for demonstrating the extracted unit area | region. It is a figure for demonstrating the reference | standard side unit area | region of a reference | standard image. It is a figure for demonstrating the search method using an epipolar straight line. It is a schematic diagram for demonstrating the cross section of the tubular body 9 specified from each of the bright lines L1-L4. It is a figure for demonstrating the 1st modification of the outer diameter acquisition method of the pipe body 9. FIG. It is a figure for demonstrating the acquisition method of the direction vector of the center line of the pipe body 9. FIG. FIG. 10 is a diagram for explaining a modification of the method for obtaining the direction vector of the center line of the tube body 9; It is a schematic diagram for demonstrating the modification of a structure of the slit laser irradiation apparatus 2 and the dot laser irradiation apparatus 3. FIG. 4 is a schematic diagram for explaining a shift between bright lines L1 to L4 and a bright spot D in the horizontal direction. FIG. FIG. 7 is a schematic view for explaining an example of the configuration of the light reflecting means 70. 4 is a flowchart for explaining a process of acquiring three-dimensional coordinates of bright lines L1 to L4 on a tubular body 9. 4 is a flowchart for explaining a calibration method for the slit laser irradiation device 2 and the imaging device 4. It is a schematic diagram for demonstrating the block 91 for calibration. It is a schematic diagram which shows the front surface of the block 91 for calibration.

<1. Configuration of Measurement System>
An overview of a measurement system S according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an example of the configuration of a measurement system S according to an embodiment.

  The measurement system S includes a control device 1, a slit laser irradiation device 2, a dot laser irradiation device 3, and an imaging device 4. In the present embodiment, the slit laser irradiation device 2 corresponds to the first irradiation means, and the dot laser irradiation device 3 corresponds to the second irradiation means.

  The control device 1 is, for example, a computer, and controls the operations of the slit laser irradiation device 2, the dot laser irradiation device 3 and the imaging device 4. The control device 1 also has a function of performing image processing on the captured image input from the imaging device 4. Although details will be described later, the control device 1 performs a process of acquiring the three-dimensional coordinates from the two-dimensional coordinates in the captured image.

The slit laser irradiation device 2 irradiates the object to be measured with a plurality of slit-shaped slit laser beams. Specifically, the slit laser irradiation device 2 simultaneously irradiates the object to be measured with a plurality of slit laser beams.
In the following, it is assumed that the object to be measured is a tubular body. However, the measurement object is not limited to this, and the object to be measured may have an arbitrary shape such as a living body.

  FIG. 2 is a diagram illustrating an example of an irradiation state of the slit laser light on the object to be measured. In FIG. 2, the dot laser irradiation device 3 is not shown for convenience of explanation. The slit laser irradiation device 2 simultaneously irradiates the tube 9 that is the object to be measured with a plurality of slit laser beams (here, four slit laser beams 23a to 23d), so that the surface of the tube 9 has an arc shape. A plurality of bright lines (here, four bright lines L1 to L4) appear. Note that the irradiation direction of the four slit laser beams 23a to 23d to the tube body 9 is not parallel but intersects each other. Moreover, the irradiation directions (irradiation angles) of the four slit laser beams 23a to 23d are set in advance.

  FIG. 3 is a schematic view for explaining an example of the configuration of the slit laser irradiation device 2 and the dot laser irradiation device 3. FIG. 3 is a view of the slit laser irradiation device 2 and the dot laser irradiation device 3 as seen from the tube 9 side in FIG. The slit laser irradiation apparatus 2 includes four slits 21 that are elongated openings, and a laser element (not shown) that is provided inside the apparatus and emits laser light. The laser light emitted from the laser element passes through the four slits 21 and is irradiated onto the tube body 9.

  The slit laser irradiation device 2 and the dot laser irradiation device 3 are located on the same straight line in the slit direction, which is the longitudinal direction of the slit on which the slit laser irradiation device 2 irradiates slit laser light. That is, the slit laser irradiation device 2 and the dot laser irradiation device 3 have a focal point which is the origin of divergence of the slit laser light irradiated by the slit laser irradiation device 2 and a focal point of the dot laser light irradiated by the dot laser irradiation device 3. , And fixed so as to be on the same straight line in the slit direction. In the present embodiment, as shown in FIG. 3, the slit laser irradiation device 2 is positioned directly above the dot laser irradiation device 3 in the slit direction (z-axis direction). However, the present invention is not limited to this, and the slit laser irradiation device 2 may be located directly below the dot laser irradiation device 3.

  Returning to FIG. 1, the dot laser irradiation device 3 irradiates the tube body 9 with a plurality of dot-shaped dot laser beams. The dot laser irradiation device 3 is configured to be able to irradiate dot laser light at random.

  The dot laser irradiation device 3 includes a large number of holes 31 as shown in FIG. 3 and a laser element (not shown) provided inside the device and emitting laser light. The laser light emitted from the laser element passes through the hole 31 and is irradiated to the tube body 9. Although it is shown in FIG. 3 that the large number of holes 31 are regularly arranged at predetermined intervals, the large number of holes 31 are arranged such that the distance between the holes 31 is random. Thereby, it becomes possible to irradiate dot laser light at random.

  In the present embodiment, the dot laser irradiation device 3 irradiates the tube body 9 with a plurality of dot laser beams when the slit laser irradiation device 2 irradiates the tube body 9 with the plurality of slit laser beams 23a to 23d. Here, the plurality of dot laser beams have a predetermined positional relationship with each of the slit laser beams 23a to 23d.

  FIG. 4 is a diagram for explaining the positional relationship between the slit laser beam and the dot laser beam. Here, as shown in FIGS. 4A and 4B, the slit laser irradiation apparatus 2 irradiates a predetermined area on a flat surface with a slit laser beam, and the dot laser irradiation apparatus 3 also applies dots to the predetermined area. It shall be irradiated with laser light. When the slit laser beam is irradiated, four bright lines L1 to L4 as shown in FIG. 4A appear on the surface of the tube 9 and the dot laser beam is irradiated, as shown in FIG. A large number of random bright spots D as shown in b) appear on the surface of the tube body 9.

  As described above, since the slit laser irradiation device 2 is positioned right above the slit direction of the dot laser irradiation device 3, when the slit laser light and the dot laser light are simultaneously irradiated, the bright lines L1 to L4 and the bright spot D are The positional relationship is as shown in FIG. 4 (c). As can be seen from FIG. 4C, the bright lines L1 to L4 and the bright spot D are displaced in the slit direction (vertical direction) due to the parallax from the camera, but the bright lines L1 to L4 and the bright spot D are in the slit direction. There is no deviation in the direction perpendicular to the left and right direction.

  Returning to FIG. 1, the imaging device 4 is a camera, for example, and images the tubular body 9 irradiated with the slit laser beams 23 a to 23 d and the dot laser beams to generate a captured image. That is, the imaging device 4 emits a plurality of bright laser beams L1 to L4 appearing on the surface of the tube 9 by being irradiated with a plurality of slit laser beams and a plurality of dot laser beams on the surface of the tube 9. A plurality of bright spots D that appear are captured to generate a captured image.

  As shown in FIG. 2, the imaging device 4 images the tubular body 9 in a direction in which the irradiation direction of the slit laser irradiation device 2 and the line-of-sight direction intersect. The imaging device 4 is attached to the table 6 (FIG. 2) so that the positional relationship with the slit laser irradiation device 2 is maintained. That is, during measurement, the angle between the installation direction of the imaging device 4 and the installation direction of the slit laser irradiation device 2 and the distance between the imaging device 4 and the slit laser irradiation device 2 are fixed at a predetermined size. The slit laser irradiation device 2 and the dot laser irradiation device 3 are also attached to the table 6.

  FIG. 5 is a diagram illustrating an example of a captured image. The captured image is an image showing the tubular body 9 in which four bright lines L1 to L4 and a large number of bright spots D appear on the surface. As can be seen from FIG. 5, the arrangement patterns of the bright spots D around the four bright lines L1 to L4 are different. That is, the dot laser irradiation device 3 randomly irradiates a plurality of dot laser beams so that the adjacent state of the bright spot D is different for each of the plurality of bright lines L1 to L4.

  Although not shown in FIG. 5, the captured image includes not only the bright lines L1 to L4 that appear on the surface of the tubular body 9 by the slit laser beams 23a to 23d, but other than the tubular body 9 by the slit laser beams 23a to 23d. (For example, the bright line appearing in the portion between the slit laser irradiation device 2 and the tube 9) is also included. A plurality of these bright lines exist as repeated patterns in the captured image, and since these repeated patterns are usually deviated, it is specified by which slit laser light the bright lines L1 to L4 on the tube 9 appeared. Hard to do.

  On the other hand, the measurement system S according to the present embodiment generates a captured image (FIG. 5) in which the bright lines L1 to L4 and the bright point D appear, and the bright lines L1 to L4 and the slit laser beams 23a to 23d and The correspondence of is identified. Then, the measurement system S calculates the three-dimensional coordinates of the bright lines L1 to L4 based on the two-dimensional coordinates of the bright lines L1 to L4 obtained from the captured image and the specified correspondence relationship. Thereby, even when the plurality of slit laser beams 23a to 23d are simultaneously irradiated onto the tube body 9, the three-dimensional coordinates of the plurality of bright lines L1 to L4 can be acquired.

  In the present embodiment, the slit laser irradiation device 2 and the dot laser irradiation device 3 and the dot laser irradiation device 3 irradiate the slit laser beam and the dot laser beam, respectively, until the imaging device 4 captures an image. The positions of the irradiation device 3 and the imaging device 4 are fixed. Thereby, since the images of the bright lines L1 to L4 can be captured at a time, the occurrence of errors due to the movement of the slit laser irradiation device 2, the dot laser irradiation device 3, and the imaging device 4 can be suppressed.

  If the length in the axial direction of the tube 9 is large, the base 6 on which the slit laser irradiation device 2, the dot laser irradiation device 3 and the imaging device 4 are attached is moved by a known predetermined amount. A captured image may be captured and connected. In such a case, using the slit laser irradiation device 2, the dot laser irradiation device 3, and the imaging device 4, the shape and position of the tubular body 9 having a large axial length can be obtained with high accuracy.

<2. Controller configuration>
The configuration of the control device 1 that acquires the three-dimensional coordinates of the bright line appearing on the surface of the object to be measured will be described with reference to FIG.
As illustrated in FIG. 1, the control device 1 includes a communication unit 11, a display unit 12, an operation unit 13, a storage unit 14, and a control unit 15.

  The communication unit 11 is a communication interface (hereinafter, communication IF) that performs communication with an external device. The communication unit 11 performs wired communication with the slit laser irradiation device 2, the dot laser irradiation device 3, and the imaging device 4 via, for example, a cable and transmits / receives information. However, the communication unit 11 may perform wireless communication with the slit laser irradiation device 2, the dot laser irradiation device 3, and the imaging device 4 without being limited thereto.

  The display unit 12 includes, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display. For example, the display unit 12 displays a captured image captured by the imaging device 4.

  The operation unit 13 includes, for example, a keyboard, a mouse, and the like, and a user can perform an input operation. The user performs various input operations related to the measurement of the object to be measured via the operation unit 13.

  The storage unit 14 is configured by, for example, a ROM, a RAM, and the like, and stores various programs and various data for causing the control device 1 to function. The storage unit 14 stores the captured image received from the imaging device 4. In addition, the storage unit 14 stores information related to a reference image indicating a predetermined positional relationship between a plurality of bright lines and bright spots appearing in the tubular body 9 described later. The reference image is used to identify slit laser light corresponding to the bright line in the captured image in comparison with the captured image. The reference image is not limited to image information such as luminance and chromaticity, and may be information that can specify the positional relationship between the slit laser beam and the dot laser beam.

  FIG. 6 is a diagram illustrating an example of the reference image. As shown in FIG. 6, the reference image is an image including four bright lines M1 to M4 and a large number of bright points D. The reference image is, for example, an image showing a predetermined area (see FIG. 4A) to which slit laser light or dot laser light is irradiated. The reference image can be set according to the combination of the slit laser irradiation device 2 and the dot laser irradiation device 3 used for measurement.

  The reference image shown in FIG. 6 is an image when a flat surface is irradiated with slit laser light and dot laser light, unlike when the cylindrical tube body 9 shown in FIG. 2 is irradiated with laser light. . For this reason, the bright lines M1 to M4 are straight lines unlike the arc-shaped bright lines L1 to L4 shown in FIG. A number of bright spots D are randomly scattered on the bright lines M1 to M4, and the scattered patterns of the bright spots D around the bright lines M1 to M4 are different from each other.

  Returning to FIG. 1, the control unit 15 is configured of, for example, a CPU. The control unit 15 comprehensively controls functions related to the control device 1 by executing various programs stored in the storage unit 14. In the present embodiment, the control unit 15 functions as the irradiation control unit 151, the identification unit 152, and the acquisition unit 153.

(Irradiation control unit 151)
The irradiation control unit 151 controls the irradiation of the slit laser light 23 a to 23 d by the slit laser irradiation device 2 and the irradiation of the dot laser light by the dot laser irradiation device 3. In the present embodiment, the irradiation control unit 151 simultaneously irradiates the object to be measured with the slit laser beams 23a to 23d.

  The irradiation control unit 151 also irradiates the dot laser light when irradiating the slit laser light 23 a to 23 d. Specifically, the irradiation control unit 151 simultaneously irradiates the slit laser beams 23a to 23d and the dot laser beam. Note that the irradiation control unit 151 may control the irradiation intensity of the slit laser beams 23a to 23d and the dot laser light in consideration of the type and shape of the object to be measured.

(Specification section 152)
The specifying unit 152 compares the captured image shown in FIG. 5 with the reference image shown in FIG. 6 and specifies the correspondence between the plurality of bright lines L1 to L4 of the captured image and the plurality of slit laser beams 23a to 23d. That is, the specifying unit 152 compares the captured image captured by the imaging device 4 when the slit laser beams 23 a to 23 d and the dot laser beam are irradiated on the tube body 9 with the reference image stored in the storage unit 14. Then, the correspondence relationship between the bright lines L1 to L4 and the slit laser beams 23a to 23d is specified.

  As described above, the irradiation directions of the slit laser beams 23a to 23d applied to the tube body 9 are different. For this reason, the specific | specification part 152 can pinpoint the irradiation direction of the slit laser beam which became the basis which shows each of the bright lines L1-L4 by specifying the correspondence of the bright lines L1-L4 and the slit laser beams 23a-23d. .

Here, an example of a method of comparing the captured image and the reference image by the specifying unit 152 will be described.
First, the specifying unit 152 extracts a unit region including one point on the bright lines L1 to L4 of the captured image as a comparison target. In this way, by comparing only the region including the points on the bright lines L1 to L4 in the captured image, the captured image and the reference image are compared with the case where all the regions of the captured image are compared. Processing time required for comparison can be shortened.

  FIG. 7A is a diagram for describing a point to be compared in a captured image. In FIG. 7A, it is assumed that a point A on the bright line L3 is a point to be compared. The specifying unit 152 extracts a small rectangular area including the periphery of the point A with the point A as the center, as a unit area.

  FIG. 7B is a schematic view for explaining the extracted unit area. Since the extracted unit region is a small region, even if the bright line L3 is arcuate, the portion of the bright line L3 in the unit region is substantially a straight line as shown in FIG. 7B. As can be seen from FIG. 7B, a plurality of bright spots D are scattered around the bright line L3 in the unit region. In the present embodiment, it is desirable that the dot laser irradiation device 3 irradiates the dot laser light so that the bright spots D are scattered in the unit region.

  Next, the specifying unit 152 selects a unit area of the extracted captured image (hereinafter referred to as an imaging-side unit area) and a unit area (hereinafter referred to as a reference-side unit area) having the same size as the imaging-side unit area on the reference image. Contrast). Then, the specifying unit 152 searches for a reference unit area including the same pattern as the scattered pattern of the bright spot D shown in FIG. 7B. For example, the specifying unit 152 compares the value of the pixel included in the imaging-side unit area with the value of the pixel included in the corresponding position of the reference-side unit area, and the number of matching pixel values is a predetermined number. When the ratio is equal to or greater than the ratio, it is determined that the reference side unit area has a large degree of correlation with the imaging side unit area and includes the same pattern.

FIG. 8 is a diagram for explaining the reference side unit area of the reference image.
The identifying unit 152 sequentially searches the reference side unit region including the points on the bright lines M1 to M4 along the bright lines M1 to M4. Thereby, since the area | region used for a search can be limited, search time can be suppressed. In FIG. 8, it is assumed that the scattered pattern of the bright spots D in the reference side unit region R centering on the point on the bright line M3 is the same as the scattered pattern of the bright spots D in FIG. 7B. Then, the specifying unit 152 determines that the degree of correlation between the imaging-side unit region including the point A of the captured image and the reference-side unit region R of the reference image is large.

  In the above description, the reference-side unit region is sequentially searched along the bright lines M1 to M4. However, the present invention is not limited to this. For example, the specifying unit 152 can efficiently search for the same reference side unit area as the scattered pattern of the bright spots D of the imaging side unit area by using the epipolar straight line.

  FIG. 9 is a diagram for explaining a search method using epipolar lines. In FIG. 9, the straight line N is an epipolar straight line passing through the point A in FIG. 7A. The epipolar straight line N is a straight line on which a line connecting the point A and the slit laser irradiation device 2 is projected. Therefore, the point A is located on the epipolar straight line N. By using such an epipolar straight line, the specifying unit 152 has four reference-side units centered on the imaging-side unit region and the intersections (four points) of the bright lines M1 to M4 and the epipolar straight line N in the reference image. Contrast with the area. Thereby, since the area | region to search can be limited, the processing time which a search requires can be suppressed.

(Acquisition unit 153)
Returning to FIG. 1, the acquisition unit 153 acquires the three-dimensional shape of the tubular body 9 captured by the imaging device 4. Specifically, first, the acquisition unit 153 determines two-dimensional coordinates of the bright lines L1 to L4 appearing on the surface of the tube 9 with reference to the captured image captured by the imaging device 4. Next, the acquisition unit 153 determines the two-dimensional coordinates of the bright lines L1 to L4 and the correspondence specified by the specifying unit 152 (that is, the irradiation direction of the slit laser beams 23a to 23d on which the bright lines L1 to L4 are based). Based on the three-dimensional coordinates of the bright lines L1 to L4 are acquired.

For example, the acquisition unit 153 uses the principle of triangulation to calculate the bright lines L1 to L4 from the two-dimensional coordinates of the bright lines L1 to L4 and the plane equations of the slit laser beams 23a to 23d on which the bright lines L1 to L4 are based. The distance between the bright line L4 and the imaging device 4 is determined. Then, the acquisition unit 153 acquires the three-dimensional coordinates of the bright lines L1 to L4 based on the two-dimensional coordinates of the bright lines L1 to L4 and the distance between the bright lines L1 to L4 and the imaging device 4. Note that the three-dimensional coordinates of the bright lines L1 to L4 are, for example, equations (4.18) (equations (4.16) and (4.17) described in the book “Three-dimensional image measurement” (by Seiji Iguchi and Kosuke Sato)). See also)). The two-dimensional coordinates (u, v) of the bright line correspond to X _c and Y _c in the equation (4.16), respectively.

  The acquisition unit 153 further acquires the cross-sectional shape of the tubular body 9 based on the three-dimensional coordinates of the bright lines L1 to L4. In the present embodiment, the acquisition unit 153 acquires the three-dimensional coordinates of the cross-sectional shape of the tubular body 9 formed by the arcuate bright lines L1 to L4. Specifically, the acquisition unit 153 acquires an elliptical cross section as shown in FIG.

  FIG. 10 is a schematic view for explaining the cross section of the tube 9 identified from each of the bright lines L1 to L4. The acquisition unit 153 acquires four elliptical cross sections F1 to F4 illustrated in FIG. 10 based on the arc-shaped bright lines L1 to L4. Here, the cross section F1 includes the bright line L1 as a part, the cross section F2 includes the bright line L2 as a part, the cross section F3 includes the bright line L3 as a part, and the cross section F4 includes the bright line L4 as a part.

  The acquiring unit 153 may acquire the outer diameter of the tubular body 9 based on the acquired cross sections F1 to F4. Specifically, the acquiring unit 153 acquires the minor axis (diameter in the minor axis direction) of the ellipse that is the cross-sectional shape, and sets the acquired minor axis as the outer diameter (diameter) of the tube 9. The reason why the minor axis of the ellipse is the outer diameter of the tube 9 is that, originally, when the tubular body 9 is cut in a plane orthogonal to the axial direction, it becomes a perfect circle of the same diameter as the minor axis of the ellipse. Because. In addition, the acquisition part 153 is good also considering the average value of the short diameter of each ellipse of the four cross sections F1-F4 as the outer diameter of the tubular body 9. FIG. Thereby, the outer diameter of the pipe body 9 can be acquired accurately.

  The acquisition unit 153 may acquire the center line of the tubular body 9 based on the acquired four cross sections F1 to F4. Specifically, the acquisition unit 153 acquires a straight line C passing through the centers of the four cross sections F <b> 1 to F <b> 4 as the center line of the tubular body 9 as illustrated in FIG. 10. By acquiring the center line and the cross-sectional shape in this way, it becomes easy to specify the three-dimensional shape of the tube body 9.

(Modification)
In the above, when the cross-sectional shape is an ellipse, the acquisition unit 153 sets the minor diameter of the ellipse as the outer diameter of the tube 9, but is not limited thereto. For example, the acquisition unit 153 may set the outer diameter of the tubular body 9 based on the size of a perpendicular line dropped from the point on the ellipse having a cross-sectional shape to the center line of the tubular body 9.

FIG. 11 is a diagram for explaining a first modification of the outer diameter acquisition method of the tube body 9. In FIG. 11A, for convenience of explanation, only two cross sections F1 and F2 of the tubular body 9 obtained from the bright lines L1 and L2 are shown. Here, the method to acquire the outer diameter of the pipe body 9 using the cross section F1 is demonstrated. The acquisition unit 153 forms a plurality of perpendiculars H from the point on the ellipse that is the shape of the cross section F1 toward the center line C, and sets the average value of the sizes of the plurality of perpendiculars H as the outer diameter of the tubular body 9. .
The acquisition unit 153 forms a plurality of vertical lines H from the point of the bright line L1 toward the center line C instead of the ellipse having the shape of the cross section F1, and obtains an average value of the sizes of the plurality of vertical lines H. You may set as an outer diameter of 9.

  FIG. 12A is a diagram for explaining a method of acquiring the direction vector of the center line of the tubular body 9. The acquisition unit 153 identifies a straight line D that passes through points G1 to G4 that are closest to an arbitrary plane set in the space on the four bright lines L1 to L4. The straight line D is a line parallel to the center line C of the tube 9 and defined as a direction vector of the center axis of the tube.

FIG. 12B is a diagram for describing a modification of the method for obtaining the direction vector of the center line of the tubular body 9. In FIG. 12B, for convenience of explanation, three cross sections F1 to F3 are shown. Acquisition of the direction vector of the center line is performed as follows.
First, one point J on the cross section F1 on the slit laser bright line is specified. Next, a straight line connecting the point J on the cross section F1 and the point on the cross section F2 is specified. For example, specifying a straight line D3 through a point J, the point _{K 3} on the section F2. Similarly, straight lines D1 and D2 passing through the point J and other points on the cross section F2 (as an example, points K ₁ and K ₂ ) are specified. And the distance d between the straight lines D1-D3 and the cross section F3 is calculated | required, and the straight line with the shortest distance d between the cross sections F3 is calculated | required. In FIG. 12, the distance between the straight line D1 and the cross section F3 is 0, and the straight line D1 is a straight line passing through the three cross sections F1 to F3. The straight line D1 thus obtained is the direction vector of the center line of the tube 9.

  Further, although the slit laser irradiation device 2 and the dot laser irradiation device 3 are provided along the slit direction (Z direction) as shown in FIG. 3 in the above description, the present invention is not limited to this. For example, as shown in FIG. 13, the slit laser irradiation device 2 and the dot laser irradiation device 3 may be provided along a direction (X direction) perpendicular to the slit.

  FIG. 13 is a schematic view for explaining a modification of the configuration of the slit laser irradiation device 2 and the dot laser irradiation device 3. In the modification, the dot laser irradiation device 3 is positioned perpendicularly to the slit from the slit laser irradiation device 2 by a predetermined distance.

  By the way, as shown in FIG. 13, when the slit laser irradiation device 2 and the dot laser irradiation device 3 are arranged perpendicularly to the slit, bright lines appearing on the surface of the tube body 9 as shown in FIG. And the position of the bright spot will shift.

  FIG. 14 is a schematic diagram for explaining the deviation between the bright lines L1 to L4 and the bright spot D in the direction perpendicular to the slit. As can be seen by comparing FIG. 14 and FIG. 4C, when the slit laser irradiation device 2 and the dot laser irradiation device 3 are disposed vertically away from the slit, the bright lines L1 to L4 and the bright spot D However, it is shifted by the distance between the slit laser irradiation device 2 and the dot laser irradiation device 3. In this case, there is a possibility that the specifying unit 152 cannot accurately compare the captured image including the bright lines L1 to L4 and the bright spot D that are in a shifted relationship with the reference image. Therefore, in order to solve such a problem, it is desirable to provide a light reflecting means 70 as shown in FIG.

  FIG. 15 is a schematic view for explaining an example of the configuration of the light reflecting means 70. As shown in FIG. In FIG. 15, the optical path of the slit laser light irradiated by the slit laser irradiation device 2 and the optical path of the dot laser light irradiated by the dot laser irradiation device 3 are indicated by broken lines. The light reflecting means 70 has a function of adjusting the irradiation position of the slit laser light on the tube 9 in the direction perpendicular to the slit and the irradiation position of the dot laser light on the tube 9.

  As shown in FIG. 15, the light reflecting means 70 includes a mirror 71 and a beam splitter 72. The mirror 71 is located in front of the dot laser irradiation device 3. The mirror 71 reflects the dot laser light irradiated by the dot laser irradiation device 3 toward the beam splitter 72. The beam splitter 72 is located in front of the slit laser irradiation device 2. The beam splitter 72 is a half mirror that transmits the slit laser light while reflecting the dot laser light.

  In FIG. 15, for convenience of explanation, the direction (X direction) in which the optical axis of the slit laser beam transmitted through the beam splitter 72 and the optical axis of the dot laser beam reflected by the beam splitter 72 are perpendicular to the slit Are shown as being separated. However, actually, the mirror 71 and the beam splitter 72 are arranged so that the optical axis of the slit laser light and the optical axis of the dot laser light overlap in a direction perpendicular to the slit. Thereby, even when the slit laser irradiation device 2 and the dot laser irradiation device 3 are disposed as shown in FIG. 13, it is possible to eliminate the deviation between the bright line and the bright spot in the direction perpendicular to the slit.

<3. Acquisition processing of three-dimensional coordinates of bright line>
With reference to FIG. 16, the processing for acquiring the three-dimensional coordinates of the bright lines (here, the bright lines L <b> 1 to L <b> 4 shown in FIG. 5) on the tubular body 9 that is the object to be measured by the control device 1 (FIG. 1) will be described. The acquisition process of the three-dimensional coordinates of the bright line is realized by the control unit 15 of the control device 1 executing a program stored in the storage unit 14.

  FIG. 16 is a flowchart for explaining the process of acquiring the three-dimensional coordinates of the bright lines L1 to L4 on the tube body 9. This flowchart is started when the operator sets the slit laser irradiation device 2, the dot laser irradiation device 3, the imaging device 4, and the tube 9 at the measurement positions.

  First, the irradiation control unit 151 of the control unit 15 operates the slit laser irradiation device 2 and the dot laser irradiation device 3 to irradiate the tube 9 with the slit laser light 23a to 23d and the dot laser light (step S102). Specifically, the irradiation control unit 151 irradiates the tube body 9 with the slit laser beams 23a to 23d and the dot laser beam at the same time. Thus, four bright lines L1 to L4 and a plurality of random bright spots D appear on the surface of the tube 9.

  Next, the control unit 15 operates the imaging device 4 to image the tube 9 in which four bright lines L1 to L4 and a plurality of random bright spots D appear on the surface (Step S104). Then, the imaging device 4 generates a captured image including, for example, the bright lines L1 to L4 and the plurality of bright spots D as illustrated in FIG. 5 and transmits the captured image to the control unit 15.

  Next, the specifying unit 152 of the control unit 15 extracts the bright lines L1 to L4 from the captured image (step S106). For example, the specifying unit 152 extracts the bright lines L1 to L4 from the captured image using a known median filter or the like.

  Next, the identifying unit 152 calculates the coordinates (u, v) of the extracted bright lines L1 to L4 (step S108). Specifically, the specifying unit 152 calculates the coordinates (u, v) of the bright lines L1 to L4 after thinning the extracted bright lines L1 to L4. By thinning the extracted bright lines L1 to L4, the amount of calculation can be reduced when the captured image and the reference image are compared. The specifying unit 152 may calculate the coordinates (u, v) of the bright lines L1 to L4 without performing the thinning process.

  Next, the specifying unit 152 generates an image of a unit area including one point A (u, v) on a bright line (here, the bright line L3 shown in FIG. 7A is described as an example) (hereinafter also referred to as a peripheral image). Is extracted (step S110). At this time, the specifying unit 152 may delete the bright lines L1 to L4 and extract a peripheral image in which the bright points D are scattered. Erasure of the bright lines L1 to L4 is realized, for example, by deleting the bright lines L1 to L4 extracted in step S106 from the captured image generated in step S104.

  Next, the specifying unit 152 searches for a unit area (reference side unit area) having the same pattern as the scattered pattern of the bright spot D of the peripheral image in the reference image stored in the storage unit 14 (step S112). For example, the specifying unit 152 searches for the reference-side unit region including the points on the bright lines M1 to M4 by the search method described with reference to FIGS.

  Then, when there is a reference unit region including the same pattern in the reference image (step S114: Yes), the specifying unit 152 specifies that the slit laser light corresponding to the bright line L3 is the slit laser light 23c ( Step S116).

  When the same pattern is not found in step S114, the specifying unit 152 extracts a peripheral image around the next point on the bright line L3 (step S120), and the scattered pattern of the bright points D of the peripheral image is extracted. The same pattern is searched (step S112).

  When the slit laser light corresponding to the bright lines L1 to L4 is specified, the acquiring unit 153 determines the two-dimensional coordinates of the four bright lines L1 to L4, the bright lines L1 to L4 specified by the specifying unit 152, and the slit laser light 23a to 23d. The three-dimensional coordinates of the bright lines L1 to L4 are obtained based on the corresponding relationship with (step S118). And the acquisition part 153 calculates | requires the cross-sectional shape, centerline, etc. of the tubular body 9 based on the three-dimensional coordinate of the bright lines L1-L4, and acquires the shape of the tubular body 9. FIG.

<4. Calibration>
The measurement system S performs calibration of the parameters of the slit laser irradiation device 2 and the imaging device 4 in advance in order to accurately acquire the three-dimensional coordinates of the bright lines L1 to L4 on the tube body 9 described above. There is. The calibration is performed before the acquisition processing of the three-dimensional coordinates of the bright lines L1 to L4, for example, when the slit laser irradiation device 2 or the imaging device 4 is changed or the object to be measured is changed.

  FIG. 17 is a flowchart for explaining a calibration method of the slit laser irradiation device 2 and the imaging device 4. The flowchart shown in FIG. 17 is started when the calibration block 91 shown in FIG. 18 is set at the position of the tubular body 9 shown in FIG.

  FIG. 18 is a schematic diagram for explaining the calibration block 91. FIG. 19 is a schematic diagram showing the front surface of a rectangular parallelepiped calibration block 91. As shown in FIG. 19, the calibration block 91 includes a scale portion 92 to which a graph paper is pasted, and a graphic portion and a marker portion 93 to be pasted.

  The scale portion 92 is for measuring the actual three-dimensional coordinates of the bright line appearing on the front surface of the calibration block 91 when the slit laser irradiation device 2 irradiates the calibration block 91 with the slit laser light. . The scale portion 92 is also attached to the upper surface and the lower surface of the calibration block 91. The actual three-dimensional coordinates of the bright line are measured, for example, by a worker. The marker unit 93 is for specifying a reference position in the calibration block 91 when the imaging device 4 images the calibration block 91.

  Returning to FIG. 17, first, the slit laser irradiation apparatus 2 irradiates the calibration block 91 with slit laser light (step S202). Thus, a bright line appears on the calibration block 91. Next, the imaging block 4 captures an image of the calibration block 91 where the bright line appears (step S204). Thereby, a captured image including the bright line is generated.

  Next, the two-dimensional coordinates of the bright line in the captured image generated by the imaging device 4 are compared with the actual three-dimensional coordinates of the bright line actually measured by the operator, and the parameters of the imaging device 4 and the slit laser irradiation device 2 are compared. Are calculated (steps S206 and S208). The parameters of the imaging device 4 are constants for converting two-dimensional coordinates in the captured image into three-dimensional coordinates. The parameters of the imaging device 4 define a gaze vector from the imaging device to the bright line. The parameter of the slit laser irradiation apparatus 2 is a constant that defines the plane of each slit laser. These parameters are parameters applied to the equation (4.18) of the book “Three-dimensional image measurement” (Seiji Iguchi, Kosuke Sato), for example. Specifically, the parameter of the imaging device 4 is obtained from the above equation (4.21) of the book, and the parameter of the slit laser irradiation device 2 is obtained from the equation (4.24) of the book.

  Further, the three-dimensional coordinates of the points on the laser emission line can be obtained by calculating the intersection of the line-of-sight vector from the camera focus to each point on the emission line and the slit laser plane. For example, the obtained parameters of the imaging device 4 and the parameters of the slit laser irradiation device 2 are applied to the equation (4.18) of the book (step S210). By using the equation (4.18) to which the parameter is applied in the process of acquiring the three-dimensional coordinates of the bright line, the three-dimensional coordinates of the bright line in the captured image can be acquired with high accuracy.

  In the above description, the slit laser irradiation device 2 and the imaging device 4 are calibrated. However, the calibration is not limited to this, and the dot laser irradiation device 3 may be calibrated.

<5. Effect of the present embodiment>
The measurement system S described above has a predetermined positional relationship with each of the slit laser beams 23a to 23d when the slit laser irradiation device 2 irradiates the tube body 9, which is the object to be measured, with a plurality of slit laser beams 23a to 23d. It has the dot laser irradiation apparatus 3 which irradiates the tube body 9 with a plurality of dot laser beams in the form of dots. Then, the measurement system S preliminarily determines the picked-up image obtained by the image pickup device 4 and the bright lines and the bright spots of the tubular body 9 on which the bright lines L1 to L4 by the slit laser beams 23a to 23d and the bright spots D by the dot laser light appear. The correspondence relationship between the bright lines L1 to L4 of the captured image and the slit laser beams 23a to 23d is specified by comparing with the reference image indicating the positional relationship. Furthermore, the measurement system S acquires three-dimensional coordinates of the bright lines L1 to L4 based on the two-dimensional coordinates of the bright lines L1 to L4 in the captured image and the specified correspondence.

  As described above, each of the bright lines L1 to L4 in the captured image is a slit laser beam 23a to 23d by irradiating the dot laser light so that the bright spots D are randomly scattered to the bright lines L1 to L4. It becomes easy to specify which one appeared. As a result, the irradiation directions (irradiation angles) of the slit laser beams 23a to 23d that are the basis of the bright lines L1 to L4 are also obtained, so that the tertiary of the bright lines L1 to L4 is determined by the obtained irradiation direction and the two-dimensional coordinates of the bright lines L1 to L4. The original coordinates can be acquired. As a result, according to the present embodiment, the three-dimensional coordinates of the bright lines L1 to L4 can be obtained with high accuracy even when the tube body 9 is irradiated with the plurality of slit laser beams 23a to 23d at the same time. In particular, it is more effective when the captured image includes, in addition to the bright lines L1 to L4, other bright lines that appear in parts other than the tubular body 9 (which appear to deviate from the bright lines L1 to L4).

  Moreover, the shape of the tubular body 9 can be accurately grasped by using the three-dimensional coordinates of the bright lines L1 to L4 acquired as described above. That is, since the cross-sectional shape, outer diameter, and center line including each of the bright lines L1 to L4 of the tube body 9 can be obtained from the three-dimensional coordinates of the bright lines L1 to L4, the detailed shape of the tube body 9 can be acquired.

  Moreover, it becomes easy to grasp | ascertain the whole shape of the tubular body 9 by applying the obtained center line of the tubular body 9 to an isometric view. Further, using the obtained center line and outer diameter of the tube body 9 enables CAD.

  Further, in the above description, the slit laser light is irradiated to the tube body 9 as the object to be measured. However, the present invention is not limited to this. For example, the slit laser irradiation apparatus 2 may irradiate a measurement object having an arbitrary shape such as a living body with slit laser light. Further, the number of slit laser beams irradiated by the slit laser irradiation device 2 is not limited to four as shown in FIG. 2, and may be three or less or five or more, for example.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention. For example, in the above description, the slit laser irradiation device 2 and the dot laser irradiation device 3 are described as different devices. However, the present invention is not limited to this, and the slit laser irradiation device 2 and the dot laser irradiation device 3 are integrated. It may be an integrated device.

  Moreover, instead of using the slit laser irradiation device 2 and the dot laser irradiation device 3, a screen including vertical stripe lines and random dots is generated in a personal computer, and the generated screen is projected by the projector, thereby using the projector. Thus, the same functions as those of the slit laser irradiation device 2 and the dot laser irradiation device 3 may be realized.

  In the above embodiment, an example in which the imaging device 4 is used as the imaging unit has been described. However, a plurality of imaging devices may be used as the imaging unit.

DESCRIPTION OF SYMBOLS 1 control apparatus 2 slit laser irradiation apparatus 3 dot laser irradiation apparatus 4 imaging apparatus 9 tube 70 light reflection means 151 irradiation control part 152 identification part 153 acquisition part D bright spot L1 to L4 bright line S measurement system

Claims (12)

First irradiating means for irradiating the object to be measured with a plurality of slit laser beams in slit form;
When the first irradiation unit irradiates the plurality of slit laser beams onto the object to be measured, the plurality of dot laser beams having a predetermined positional relationship with each of the plurality of slit laser beams are Second irradiating means for irradiating the object to be measured;
Imaging a plurality of bright lines appearing on the surface of the object to be measured by being irradiated with the plurality of slit laser beams and a plurality of bright spots appearing on the surface by being irradiated with the plurality of dot laser beams. Imaging means for generating a captured image in which both the plurality of bright lines and the plurality of bright spots appear ;
Contrast the captured image with a single reference image showing a predetermined positional relationship between the plurality of bright lines and the plurality of bright spots, and the plurality of bright lines of the captured image and the plurality of slit laser beams. Specifying means for specifying the correspondence with
Obtaining means for obtaining three-dimensional coordinates of the plurality of bright lines based on two-dimensional coordinates of the plurality of bright lines in the captured image and the correspondence relationship specified by the specifying means;
Measurement system with. The first irradiation means and the second irradiation means are located on the same straight line in the slit direction which is the longitudinal direction of the slit that irradiates the slit laser light.
The measurement system according to claim 1. The first irradiation means and the second irradiation means are located apart from each other by a predetermined distance in a direction other than the slit direction,
The apparatus further comprises light reflecting means for adjusting the irradiation position of the slit laser beam on the object to be measured and the irradiation position of the dot laser beam on the object to be measured.
The measurement system according to claim 1. The direction of irradiation of the object to be measured with the plurality of slit laser beams is a direction intersecting each other,
The specifying means specifies an irradiation direction of the slit laser beam corresponding to each of the plurality of bright lines;
The measurement system according to any one of claims 1 to 3. The second irradiating means irradiates the plurality of dot laser beams so that adjacent states of luminescent spots are different for each of the plurality of bright lines.
The measurement system according to any one of claims 1 to 4. The specifying unit extracts a unit area including one point of the bright line of the captured image and a periphery of the one point, and determines a degree of correlation of the reference image with the unit area.
The measurement system according to claim 5. The object to be measured is a tubular body,
The imaging means images the plurality of bright lines and bright spots appearing on the surface of the tubular body from a line of sight direction that intersects the illumination direction of the first illumination means.
The measurement system according to any one of claims 1 to 6. The acquisition means acquires the three-dimensional coordinates of the cross-sectional shape of the tubular body, the arcuate bright line forming a part.
The measurement system according to claim 7. The cross-sectional shape is an elliptical shape,
The obtaining means obtains the minor axis of the cross-sectional ellipse, and sets the minor axis as the outer diameter of the tubular body;
The measurement system according to claim 8. The acquisition means acquires a center line of the tubular body based on a plurality of cross-sectional shapes of the tubular body, each of which is a part of the plurality of bright lines.
The measurement system according to claim 8 or 9. The acquisition means acquires a direction vector of a center line of the tubular body based on three-dimensional coordinates of points on the plurality of bright lines.
The measurement system according to any one of claims 8 to 10. Irradiating a plurality of slit-like slit laser beams in the form of a slit onto the object to be measured;
A step of irradiating the object with a plurality of dot laser beams in the form of dots having a predetermined positional relationship with each of the plurality of slit laser beams when irradiating the plurality of slit laser beams onto the object; When,
Imaging a plurality of bright lines appearing on the surface of the object to be measured by being irradiated with the plurality of slit laser beams and a plurality of bright spots appearing on the surface by being irradiated with the plurality of dot laser beams. Generating a captured image in which both the plurality of bright lines and the plurality of bright spots appear ;
Contrast the captured image with a single reference image showing a predetermined positional relationship between the plurality of bright lines and the plurality of bright spots, and the plurality of bright lines of the captured image and the plurality of slit laser beams. Identifying the correspondence with
Obtaining the three-dimensional coordinates of the plurality of bright lines based on the two-dimensional coordinates of the plurality of bright lines in the captured image and the identified correspondence relationship;
Have a measuring method.

Images