JP2019144183A - Three-dimensional coordinate measuring device and method - Google Patents

Abstract

To reduce an amount of work for three-dimensional coordinate measurement.SOLUTION: The three-dimensional coordinate measuring device 1 is disposed on a surface of an object 60 placed in an environment of natural light α, and includes six or more reflective markers 10 reflecting one monochrome light β contained in the natural light α, a light source 20 for irradiating the monochrome light β to the object 60, a filter 30 of which the transmittance of a wavelength of the monochrome light β is lower than the transmittance of other monochrome light contained in natural light 30, a camera 40 for photographing three or more images of the object 60 from different positions, respectively over the filter 30, and a three-dimensional coordinate extraction unit 50 for extracting the three-dimensional coordinates of the object 60 for performing photogrammetry at a position of the reflective marker 10 in three or more images, performing SfM using a feature point in the image excluding the result and the reflection marker 10 of the photographic measurement.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a three-dimensional coordinate measuring apparatus and method for measuring three-dimensional coordinates of an object.

  In recent years, SfM (Structure from Motion), which is an image measurement technique for restoring a three-dimensional model from a plurality of images, has started to spread. In the three-dimensional model restoration by SfM, the reliability that the three-dimensional point in the three-dimensional space is a point on the object is calculated based on the similarity between a plurality of images, and the three-dimensional point with high reliability is calculated. By using as a point on the object, three-dimensional coordinate measurement is performed.

  Since SfM calculates the reliability of a three-dimensional point using an image, the accuracy of the reliability of the three-dimensional point may deteriorate depending on the texture of the object. Therefore, for example, Patent Document 1 discloses a method of improving the accuracy of three-dimensional coordinate measurement by combining distance measurement using a laser sensor and SfM.

  Further, for example, Non-Patent Document 1 discloses a method for improving the measurement accuracy of three-dimensional coordinate measurement by combining photogrammetry and SfM. In the method of Non-Patent Document 1, shooting for obtaining a reference point (photogrammetry) and shooting for obtaining three-dimensional coordinates (SfM) are performed separately.

JP2015-49200A

S. Recker, M. M. Shashkov, M. Hess-Flores, C. Gribble, R. Baltrusch, M. A. Butkiewicz, K. I. Joy, "Hybrid Photogrammetry Structure-from-Motion Systems for Scene Measurement and Analysis." Coordinate Metrology Systems Conference, 2014.

  However, the technique of Patent Document 1 needs to perform distance measurement using a laser sensor and photographing for SfM. Further, the technique of Non-Patent Document 1 needs to perform photography for photogrammetry and photography for SfM in two steps. That is, the conventional technique has a problem that the amount of work for measuring three-dimensional coordinates is large.

  This indication aims at providing the three-dimensional coordinate measuring device and its method which can perform three-dimensional coordinate measurement with a small work amount in view of the above-mentioned subject.

In order to achieve the above object, a three-dimensional coordinate measuring apparatus according to an aspect of the present disclosure is disposed on a surface of an object placed in a natural light environment and reflects one monochromatic light included in the natural light. Six or more reflective markers, a light source that irradiates the object with the monochromatic light, a filter having a transmittance of a wavelength of the monochromatic light lower than that of other monochromatic light included in the natural light, and the filter A camera that captures three or more images of the object from different positions, and photogrammetry at the positions of the reflective markers in the three or more images, and the photogrammetric results and the reflective markers And a three-dimensional coordinate extraction unit that executes SfM using the feature points in the image excluding and extracts the three-dimensional coordinates of the object.
Further, the three-dimensional coordinate measuring apparatus according to another aspect of the present disclosure is arranged on the surface of an object placed in a natural light environment, and emits six or more light emission units that emit one monochromatic light included in the natural light. A marker, a filter having a low transmittance of the wavelength of the monochromatic light and a high transmittance of the wavelength of the other monochromatic light, and three or more images of the object are photographed from different positions through the filter. Perform photogrammetry at the position of the light emitting marker in the three or more images with the camera, execute SfM using the photogrammetric result and the feature points in the image excluding the light emitting marker, A three-dimensional coordinate extraction unit that extracts the three-dimensional coordinates of the object.
Further, the three-dimensional coordinate measurement method according to one aspect of the present disclosure is a three-dimensional coordinate measurement method executed by a three-dimensional coordinate measurement apparatus, and the natural light is applied to the surface of an object placed in a natural light environment. Six or more reflective markers that reflect one monochromatic light contained therein are arranged, the monochromatic light is irradiated onto the object, and the reflected light from the object is transmitted to the natural light with the wavelength transmittance of the monochromatic light. Filter with a filter that is lower than the transmittance of the other monochromatic light included, and take three or more images of the object through the filter from different positions, and the three or more of the reflective markers in the images Photogrammetry is executed at the position, SfM is executed using the photogrammetry result and the feature points in the image excluding the reflection marker, and the three-dimensional coordinates of the object are extracted.

  According to the present disclosure, photogrammetry is performed using a reflection marker on an image, and SfM is performed using an image excluding the reflection marker. Therefore, three-dimensional coordinates are extracted from an image obtained by one shooting. Therefore, it is possible to reduce the amount of work for measuring the three-dimensional coordinates.

It is a block diagram showing an example of functional composition of a three-dimensional coordinate measuring device concerning a 1st embodiment of this indication. It is a flowchart which shows the operation | movement flow of the three-dimensional coordinate measuring apparatus shown in FIG. It is a figure which shows typically the permeation | transmission characteristic of the filter shown in FIG. It is a figure which shows notionally the procedure which performs photogrammetry at the position of the reflective marker shown in FIG. 1, and performs SfM using the feature point in the image except the result of photogrammetry and the reflective marker. It is a figure which shows typically a mode that a three-dimensional coordinate is correct | amended with the result of photogrammetry. It is a conceptual diagram for demonstrating the relationship between the contrast of the reflective marker shown in FIG. 1, and the center position detection accuracy of a reflective marker. It is a figure which shows the result of having simulated the relationship between the contrast of a reflective marker, and detection accuracy. It is a figure which shows typically the relationship between the light source shown in FIG. 1, and the position of a camera. It is a figure which shows the result of having simulated the relationship between the angle shown in FIG. 6, and reflected luminance. It is a block diagram showing an example of functional composition of a three-dimensional coordinate measuring device concerning a 2nd embodiment of this indication.

  The configuration and operation of the three-dimensional coordinate measurement apparatus according to the embodiment of the present disclosure will be described below.

[First Embodiment]
FIG. 1 is a block diagram illustrating a functional configuration example of the three-dimensional coordinate measurement apparatus according to the first embodiment of the present disclosure.

As illustrated in FIG. 1, the three-dimensional coordinate measuring apparatus 1 according to the first embodiment includes a reflective marker 10, a light source 20, a filter 30, a camera 40, and a three-dimensional coordinate extraction unit 50. Although FIG. 1 shows an example of _three cameras 40 ₁ , 40 ₂ , and 40 ₃ , one camera 40 may be used. In the following, when it is not necessary to specify each, the reference numeral of the camera is expressed as 40. The same applies to a plurality of reflection markers 10.

  FIG. 2 is a flowchart showing an operation flow of the three-dimensional coordinate measuring apparatus 1. The operation of the three-dimensional coordinate measuring apparatus 1 will be described with reference to FIGS.

6 or more (10 ₁ , 10 ₂ ,..., 10 ₆ ,...) Are arranged on the surface of the object 60 placed in the environment of natural light α, and one monochromatic light β included in the natural light α. To reflect. The natural light α is light derived from nature such as sunlight, and also includes light emitted from a general lighting fixture arranged indoors. The natural light α is light including the wavelengths of the three primary colors (R, G, B) of light. The reflection marker 10 may be disposed at any position as long as it is the surface of the object 60 (step S1).

  The monochromatic light β is light having wavelengths of only the three primary colors of light, for example, blue. The reflective marker 10 reflects light having a blue wavelength rather than light having red and green wavelengths. The reflection amount may be any value quantitatively as long as it is relatively larger than the reflection amounts of other wavelengths on the surface of the object 60 excluding the reflection marker 10.

  The light source 20 irradiates the object 60 with the monochromatic light β (step S2). The monochromatic light β may be red or green other than the blue wavelength. In that case, the reflective marker 10 reflects light having the wavelength of the monochromatic light. Further, the reflection characteristic of the reflection marker 10 is preferably retroreflection when the light source 20 is disposed at a position close to the camera 40, for example. Details of the arrangement of the camera 40 and the light source 20 will be described later.

  The filter 30 is a filter whose transmittance of the wavelength of the monochromatic light β is lower than the transmittance of other monochromatic light included in the natural light α. FIG. 3 is a diagram schematically showing an example of the characteristic of the transmittance of the filter 30 with respect to the wavelength of light. The horizontal axis in FIG. 3 is the wavelength of light, and the vertical axis is the transmittance (%). The transmittance of blue light (dashed line) with a short wavelength is low, and the transmittance of other green and red wavelengths is high. The filter 30 filters the reflected light γ reflected by the object 60 with, for example, transmission characteristics indicated by a solid line in FIG. 3 (step S3).

The camera 40 captures three or more images of the object 60 including the reflective marker 10 through the filter 30 from different positions (step S4). In the example shown in FIG. 1, three images are simultaneously captured by _three cameras 40 ₁ , 40 ₂ , and 40 ₃ . Note that the object 60 may not be photographed simultaneously by the plurality of cameras 40 ₁ to 40 ₃ . 1 shows an example in which the cameras 40 ₁ , 40 ₂ , and 40 ₃ are arranged in the z-axis direction, it is not necessary to regularly arrange the cameras 40 in this way. It is only necessary that the positions of the respective cameras 40 ₁ , 40 ₂ , and 40 ₃ are different.

  For example, three images of the right image, the front image, and the left image as viewed from the front of the object 60 may be taken by changing the position of one camera 40. That is, the camera 40 may shoot three or more images of the object 60 from different positions through the filter 30.

  The three-dimensional coordinate extraction unit 50 performs photogrammetry at the positions of the reflection markers 10 in three or more images, and executes SfM using the photogrammetry results and feature points in the image excluding the reflection markers 10. Then, the three-dimensional coordinates of the object 60 are extracted (step S5). Here, photogrammetry and SfM are general techniques.

  The three-dimensional coordinate extraction unit 50 is realized by a computer including a ROM, a RAM, a CPU, and the like, for example. When the three-dimensional coordinate extraction unit 50 is realized by a computer, the processing content is described by a program.

  Photogrammetry is a technique for measuring the three-dimensional shape of an object from stereo images obtained by capturing the object 60 from two or more locations. The coordinates (x, y, z) of the point on the object 60 can be obtained by photogrammetry. In the present embodiment, images of the object 60 photographed from three or more locations are necessary because of optimization.

  The reason why six or more reflective markers 10 are necessary is to obtain the position and orientation of the camera 40. That is, in order to obtain a total of six unknowns of the three coordinates x, y, and z of the three-dimensional coordinates of the camera 40 and three angles for each of the three axes, six or more reflective markers 10 are required.

SfM is a technique for restoring the three-dimensional shape of the object 60 from the image of the object 60 obtained from the moving camera 40. The camera 40 may not be moved. As shown in FIG. 1, the three-dimensional coordinates of the object 60 can also be obtained from images (still images) taken by cameras 40 ₁ to 40 ₃ arranged at three or more different positions.

  According to the three-dimensional coordinate measuring apparatus 1 according to the present embodiment, the object 60 placed in the environment of natural light α is irradiated with, for example, monochromatic light β having a blue wavelength, and the image of the object 60 is filtered 30. Take a photo over. That is, in this example, in an environment where there is a lot of blue light, the object 60 on which the reflective marker 10 that reflects blue light is arranged is photographed.

  The filter 30 has, for example, low blue wavelength transmittance and high other wavelength transmittance. Therefore, it is possible to increase the brightness contrast between the reflective marker 10 and other portions in the image.

  If the brightness contrast between the reflective marker 10 and other portions is large, the position of the reflective marker 10 can be detected correctly. That is, the measurement accuracy of photogrammetry using the reflective marker 10 can be increased. The relationship between the contrast and the detection accuracy of the reflective marker 10 will be described in detail later.

  FIG. 4 is a diagram schematically illustrating an example of an image of the object 60 and an image obtained by photographing the object 60 through the filter 30. The image 41 is an image obtained by photographing the object 60 with the camera 40 in a natural light environment. The object 60 in the image 41 is, for example, a part of a pillar that supports a bridge. In the image 41, the notation of the reflective marker 10 is omitted.

The image 42 is an image obtained by photographing the blue component through the filter 30. White circles 10 ₁ (70 ₁ ) to 10 ₇ (70 ₇ ) in the image 42 represent regions of the reflective marker 10 or a light emitting marker 70 described later, which is a range with a small blue component filtered by the filter 30. Thus, for example, when an image obtained by filtering the blue component is captured in an environment where there is a lot of blue light, the position of the reflective marker 10 can be accurately identified.

  The image 43 is an image obtained by photographing the object 60 through the filter 30. The shape of the object 60 can be identified even in an image composed of red and green light components with a small blue component filtered by the filter 30. That is, the feature point of the object 60 can be identified from the image 43. A feature point is a shape that characterizes the object 60.

  The three-dimensional coordinate measuring apparatus 1 according to the present embodiment described above is arranged on the surface of the object 60 placed in the environment of natural light α and reflects six or more pieces of single-color light β included in the natural light α. The reflection marker 10, the light source 20 that irradiates the object 60 with the monochromatic light β, the filter 30 having a low transmittance of the wavelength of the monochromatic light β and a high transmittance of the wavelength of the other light, and the filter 30. Photogrammetry is performed at the position of the camera 40 that captures three or more images of the object 60 from different positions and the reflective marker 10 in the three or more images, and the photogrammetric result and the reflective marker 10 are excluded. A three-dimensional coordinate extraction unit 50 that executes SfM using the feature points in the image and extracts the three-dimensional coordinates of the object 60.

  The three-dimensional coordinate measuring method executed by the three-dimensional coordinate measuring apparatus 1 includes six or more reflections of one monochromatic light β included in the natural light α on the surface of the object 60 placed in the environment of the natural light α. The reflection marker 10 is arranged to irradiate the object 60 with the monochromatic light β, and the reflected light γ from the object 60 is low in the transmittance of the wavelength of the monochromatic light β and the transmittance of the wavelengths of other light. Filter with the high filter 30, take three or more images of the object 60 through the filter 30 from different positions, perform photogrammetry at the position of the reflective marker 10 in the three or more images, and perform the photogrammetry The SfM is executed using the result of the above and the feature points in the image excluding the reflection marker 10, and the three-dimensional coordinates of the object 60 are extracted.

  According to the three-dimensional coordinate measuring apparatus 1 and the method thereof, for example, in an environment where there is a lot of blue light, the object 60 in which the reflective marker 10 that reflects blue light is arranged on the surface is acquired by one shooting. Information for 3D coordinate measurement is acquired from the image. In other words, in the conventional technique, it is necessary to perform photography for photogrammetry and photography for SfM in two steps, whereas information necessary for three-dimensional coordinate measurement is acquired from an image acquired in one shooting. be able to. Therefore, the work amount for measuring the three-dimensional coordinates can be reduced.

  In addition, according to the three-dimensional coordinate measuring apparatus 1 and the method thereof, an image with a high brightness contrast between the reflective marker 10 and other portions can be taken, so that the photogrammetry measurement accuracy using the reflective marker 10 can be increased. . That is, since the SfM is executed using the photogrammetry result with high accuracy and the feature points in the image excluding the reflection marker 10, the three-dimensional coordinate measurement can be made highly accurate.

FIG. 5 shows the three-dimensional coordinates extracted by SfM by broken lines, and (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ ), and (x ₃ , y) obtained by photogrammetry. ₃ , z ₃ ) are shown connected by a solid line. SfM is suitable for extracting three-dimensional coordinates related to the entire shape of the object 60. However, the three-dimensional coordinates extracted by SfM are gradually shifted from the actual shape of the object 60, and the restored shape of the object 60 may be distorted.

Therefore, three highly accurate coordinates (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ ), and (x ₃ , y ₃ , z ₃ ) obtained by photogrammetry, SfM is executed using the feature points in the image excluding the reflection marker 10. By doing so, it is possible to bring the three-dimensional coordinates (broken line) extracted by SfM closer to the three-dimensional coordinates indicated by the solid line.

  In addition, although it demonstrated by the example which performs SfM using the feature point in the image except the result of photogrammetry and the reflective marker 10, it is tertiary so that the three-dimensional coordinate extracted by SfM may be corrected with the result of photogrammetry. The original coordinate extraction unit 50 may be modified.

  A three-dimensional coordinate extraction unit 51 (not shown), which is a modification of the three-dimensional coordinate extraction unit 50, performs photogrammetry using the reflection markers 10 on the images of three or more objects 60. SfM is executed using the removed image, and three-dimensional coordinates obtained by correcting the three-dimensional coordinates obtained by SfM with reference to the coordinates obtained by the photogrammetry are extracted. The three-dimensional coordinate measuring apparatus including the deformed three-dimensional coordinate extracting unit 51 can make the three-dimensional coordinate measurement more accurate than the conventional technique that extracts the three-dimensional coordinates using only SfM.

(Contrast and detection accuracy)
The relationship between the contrast of the reflective marker 10 and the detection accuracy of the center position of the reflective marker 10 was examined. FIG. 6 is a diagram illustrating a method for evaluating the relationship between the contrast of the reflective marker 10 in the image and the detection accuracy of the center position of the reflective marker 10.

  An image 61 shown in FIG. 6 is obtained by dividing the image of the reflective marker 10 with a mesh in order to digitize the image of the reflective marker 10. If all the images divided by the mesh are the reflection markers 10, for example, a numerical value 1.00 is assigned to the mesh. If a portion that is not the reflective marker 10 is included in the image divided by the mesh, a numerical value (for example, 0.23) corresponding to the ratio is given to the mesh.

  An image 62 shown in FIG. 6 is an image obtained by digitizing the reflective marker 10 with, for example, an 8-bit monochrome image using the numerical values given to the mesh as described above. From this image 62, the center coordinates of the reflective marker 10 can be obtained.

  An image 63 and an image 64 shown in FIG. 6 are images schematically showing how an error is added to an image obtained by digitizing the reflective marker 10. The image 64 is an image obtained by adding a normal distribution error with a standard deviation σ = 3 to the image 63. It can be seen that the outline of the reflective marker 10 is blurred due to the added error.

  After setting the center coordinates of the reflective marker 10 in this way, an image 64 with a normal distribution error with a standard deviation σ = 3 is prepared. And the center coordinate of the reflective marker 10 is measured from the image in which the contrast of the image 64 is changed.

An image 65 shown in FIG. 6 shows the center coordinates (set value) of the reflective marker 10 set as described above and the measurement position (measured value) of the reflective marker 10 measured from the image with an error added as described above. It is an image. By evaluating the magnitude of the detection error by changing the contrast of the image 64, the contrast necessary for accurately detecting the position of the reflective marker 10 can be obtained. The contrast is the maximum luminance value in the image 64 (L _max ) ÷ the minimum luminance value in the image 64 (L _min ).

  FIG. 7 is a diagram illustrating a result of simulating the detection accuracy of the reflective marker 10 by changing the contrast. The horizontal axis in FIG. 7 is the contrast, and the vertical axis is the detection accuracy [pixel] of the reflective marker 10.

  As shown in FIG. 7, the detection accuracy increases as the contrast increases. By setting the contrast to 100 or more, the detection accuracy of the center position of the reflective marker 10 is stabilized at 0.015 [pixel] or less.

  From this simulation result, it can be seen that the contrast between the brightness of the reflective marker 10 in the image and the brightness of the feature points excluding the reflective marker 10 is preferably 100 or more. That is, when the contrast of the brightness of the reflective marker 10 in the image is set to 100 or more, more accurate photogrammetry can be executed and three-dimensional coordinate measurement can be made highly accurate.

(Arrangement of camera and light source)
As described above, when the camera 40 and the light source 20 are integrated like a strobe (both are close to each other), the reflection characteristic of the reflection marker 10 is preferably retroreflection. However, the camera 40 and the light source 20 may be arranged at positions separated from each other. Then, when the camera 40 and the light source 20 were arrange | positioned away, it examined about how the reflection intensity of the reflective marker 10 changed.

  FIG. 8 is a diagram schematically showing the positions of the camera 40 and the light source 20. As shown in FIG. 8, how the reflection intensity of the reflective marker 10 changes when the angle θ formed by the straight line 81 connecting the object 60 and the light source 20 and the straight line 82 connecting the object 60 and the camera 40 is changed. We examined whether to change.

  FIG. 9 is a diagram illustrating a change in the reflection intensity of the reflection marker 10 with respect to the angle θ. The horizontal axis in FIG. 9 is the angle θ [deg], and the vertical axis is the reflection intensity. The solid line characteristic (■) shown in FIG. 9 is for the case where the reflective marker 10 is a diffuse reflection marker, and the broken line characteristic (●) is for a retroreflection marker.

  As shown in FIG. 9, in the case of the diffuse reflection marker, the reflection intensity is constant even if the angle θ is changed in the range of 0 to 70 [deg]. On the other hand, the retroreflective marker exhibits a characteristic that the reflection intensity is larger than that of the diffuse reflection marker in the range of the angle θ = 20 [deg] or less.

  Thus, when the reflective marker 10 is configured by a retroreflective marker, the angle θ formed by the straight line 81 connecting the object 60 and the light source 20 and the straight line 82 connecting the object 60 and the camera 40 is 20 [deg] or less. It can be seen that the reflection intensity of the reflection marker 10 can be increased. Conversely, when the angle θ is 20 [deg] or more, it is preferable to use a diffuse reflection marker.

  That is, the reflective marker 10 has retroreflection characteristics, and an angle θ formed by a straight line 81 connecting the object 60 and the light source 20 and a straight line 82 connecting the object 60 and the camera 40 is 20 [deg] or less. Thereby, the position of the reflective marker 10 can be accurately detected, and the three-dimensional coordinate measurement can be made highly accurate. Note that the reflection luminance at θ = 0 [deg] shown in FIG. 9 was measured (imaged) by arranging the camera 40 and the light source 20 from the symmetrical object 60 at the same distance on the θ = 0 [deg] line. To arrange the camera 40 and the light source 20 at the same distance on the same line, it is easy to configure the light source 20 like a ring light (reference: http://www.nissin-japan.com/mf18.html), for example. Can be realized. Further, even in retroreflective markers, the reflection direction of reflected light has a certain variation. Therefore, the object 60 can be imaged by changing the plane of the camera 40 and the light source 20 even on the line θ = 0 [deg].

[Second Embodiment]
FIG. 10 is a block diagram illustrating a functional configuration example of the three-dimensional coordinate measurement apparatus according to the second embodiment of the present disclosure.

  As shown in FIG. 10, the 3D coordinate measuring apparatus 2 according to the second embodiment is different in that a light emitting marker 70 is provided instead of the reflective marker 10 of the 3D coordinate measuring apparatus 1 (FIG. 1). Since the light emitting marker 70 emits light by itself, the light source 20 provided in the three-dimensional coordinate measuring apparatus 1 is unnecessary. Other configurations except the light emitting marker 70 and the light source 20 are the same as those of the three-dimensional coordinate measuring apparatus 1.

  The three-dimensional coordinate measuring apparatus 2 is arranged on the surface of an object 60 placed in an environment of natural light α, and includes six or more light-emitting markers 70 that emit one monochromatic light β included in the natural light α, and monochromatic light. a filter 30 having a low transmittance for the wavelength of β and a high transmittance for the wavelength of other monochromatic light, and a camera 40 for taking three or more images of the object 60 through the filter 30 from different positions, 3 The photogrammetry is executed at the position of the light emitting marker 70 in one or more images, the SfM is executed using the photogrammetry result and the feature points in the image excluding the light emitting marker 70, and the three-dimensional coordinates of the object 60 And a three-dimensional coordinate extraction unit 50 for extracting.

  According to the three-dimensional coordinate measuring apparatus 2 according to the present embodiment, information necessary for three-dimensional coordinate measurement can be acquired from one image acquired by one imaging. Therefore, the work amount for measuring the three-dimensional coordinates can be reduced. Moreover, since SfM is performed using the photogrammetry result with high accuracy by the light emitting marker 70 and the feature points in the image excluding the light emitting marker 70, the three-dimensional coordinate measurement can be made highly accurate. Moreover, the effect which makes the light source 20 required in the three-dimensional coordinate measuring device 1 unnecessary is also acquired.

  The light emitting marker 70 is preferably a uniform diffused light source. The uniform diffused light source is a light source having a substantially constant luminance when viewed from any direction. Thereby, three-dimensional coordinate measurement can be made highly accurate.

  In the present embodiment, the monochromatic light β is emitted from the object 60. Therefore, for the camera 40 that captures the reflected light γ from the object 60 including the monochromatic light β from different positions, the light emitting marker 70 is preferably a uniform diffused light source.

  As described above, the three-dimensional coordinate measuring apparatuses 1 and 2 according to the present embodiment acquire an image for photogrammetry and an image for SfM by one shooting. One of the three channels of the three primary colors of light constituting an image acquired by one shooting is set as a detection channel of the reflective marker 10.

  Then, an environment in which the light of the detection channel of the reflection marker 10 is increased (irradiated or emitted) is created, and the object 60 is photographed through the filter 30 that filters the light of the detection channel in the environment. Therefore, the contrast between the brightness of the reflective marker 10 and the brightness of the surface of the other object 60 can be increased, and the three-dimensional coordinate measurement can be made highly accurate.

  As mentioned above, although this indication was explained in detail using each embodiment, this indication is not limited to the embodiment explained in this specification. For example, although one example of the filter 30 is shown, a filter may be arranged in the lens portion of each camera 40.

  Moreover, although the example of the light source 20 which irradiates the monochromatic light of a blue wavelength was demonstrated, this indication is not limited to this example. The light source 20 may be a light source that emits red or green monochromatic light. In that case, a filter 30 for filtering each monochromatic light may be used.

  Further, although the three-dimensional coordinate extraction unit 50 has been described as an example realized by a computer, it may be realized by dedicated hardware. Thus, the present disclosure is not limited to the above embodiment. The scope of the present disclosure is determined by the description of the claims and the scope equivalent to the description of the claims.

DESCRIPTION OF SYMBOLS ₁ , 2 ... Three-dimensional coordinate measuring device, 10 (10 < ₁ > -10 < ₇ >) ... Reflection marker, 20 ... Light source, 30 ... Filter, 40 (40 < ₁ > -40 < ₃ >) ... Camera, 50, 51 ... Three-dimensional coordinate extraction part , 60 ... object, 70 (70 ₁ to 70 ₇ ) ... luminous marker, α ... natural light, β ... monochromatic light, γ ... reflected light.

Claims (5)

Six or more reflective markers that are arranged on the surface of an object placed in an environment of natural light and reflect one monochromatic light contained in the natural light,
A light source for irradiating the object with the monochromatic light;
A filter whose transmittance of the wavelength of the monochromatic light is lower than the transmittance of other monochromatic light included in the natural light;
A camera that captures three or more images of the object from different positions through the filter;
Perform photogrammetry at the position of the reflection marker in three or more of the images, perform SfM using the photogrammetry results and feature points in the image excluding the reflection marker, A three-dimensional coordinate measuring apparatus comprising: a three-dimensional coordinate extracting unit that extracts three-dimensional coordinates. Six or more luminescent markers that are arranged on the surface of an object placed in a natural light environment and emit one monochromatic light contained in the natural light,
A filter having a low transmittance of the wavelength of the monochromatic light and a high transmittance of the wavelength of the other monochromatic light;
A camera for taking three or more images of the object through the filter from different positions;
Perform photogrammetry at the positions of the luminescent markers in three or more of the images, perform SfM using the photogrammetry results and feature points in the image excluding the luminescent markers, A three-dimensional coordinate measuring apparatus comprising: a three-dimensional coordinate extracting unit that extracts three-dimensional coordinates. The reflective marker is
2. The three-dimensional image according to claim 1, wherein an angle formed by a straight line having retroreflective properties and a line connecting the object and the light source and a line connecting the object and the camera is 20 degrees or less. 3. Coordinate measuring device. The light emitting marker is
The three-dimensional coordinate measuring apparatus according to claim 2, wherein the three-dimensional coordinate measuring apparatus is a uniform diffusion light source. A three-dimensional coordinate measurement method executed by the three-dimensional coordinate measurement apparatus,
On the surface of an object placed in a natural light environment, six or more reflective markers that reflect one monochromatic light included in the natural light are arranged,
Irradiating the object with monochromatic light,
Filtering the reflected light from the object with a filter whose transmittance of the wavelength of the monochromatic light is lower than the transmittance of other monochromatic light included in the natural light,
Take three or more images of the object through the filter from different positions,
Perform photogrammetry at the position of the reflection marker in three or more of the images, perform SfM using the photogrammetry results and feature points in the image excluding the reflection marker, A three-dimensional coordinate measuring method characterized by extracting three-dimensional coordinates.