JP2007051893A - Method and device for measuring three-dimensional geometry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide simplified constitution in a method and device for measuring three-dimensional geometry. <P>SOLUTION: The illuminating light emitted from a light projector 101 is structured by a first illumination light converter 102, and after restructured by a second illumination light converter 103, projected on an object 200. The first illumination light converter 102 and the second illumination light converter 103 are arranged in parallel, and a photographic part 300 can take the image of the object 200 being irradiated with structured illuminating light emitted by the light projector 101. The positional relation between the photographic part 300 and the light projector 101 has been measured previously. A moving device 104 is capable of moving in a direction of maintaining the distance between the first illumination light converter 102 and the second illumination light converter 103, while keeping the second illumination light converter 103 and the first illumination light converter 102 parallel, then the photographing is started by depressing the photographic switch 301. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a three-dimensional shape measuring method and a three-dimensional shape measuring apparatus for measuring the shape of an object.

  The slit light projection method, which is one of the three-dimensional shape measurement methods, projects a slit pattern onto a subject, acquires an image from a position different from the slit pattern projection position, and restores the three-dimensional shape using triangulation. It is a method to do. Similarly, there is a spatial coding method as a method for projecting a pattern onto a subject and restoring a three-dimensional shape.

  Spatial coding is a method of projecting a striped pattern by blocking light from a light source with a physical pattern mask, and mechanically switching between a plurality of open plates and films, or a disk-shaped pattern mask In this method, the light pattern is generated in time series by rotating the. A method of realizing this with a liquid crystal shutter is well known.

Patent Document 1 discloses a conventional shape measuring method. According to Patent Document 1, as a shape measurement method, an illumination method including a binary illumination process in which the amount of light is binarized and an irradiation distribution correction process in which the binarized illuminance distribution is modified into a sinusoidal shape is taken. The accuracy of shape measurement can be improved by optimizing each process independently and precisely controlling the radiation distribution.
JP 2002-267430 A

  However, when measuring a three-dimensional shape with high accuracy, the method of mechanically switching pattern masks requires that the position of the pattern mask before switching and the position of the pattern mask after switching be placed at exactly the same position. Therefore, the machine becomes expensive and large.

  Recently, there is a method of switching with a liquid crystal mask instead of switching a pattern mask, but this causes a high cost and complicated wiring.

  In addition to the spatial coding method, there is a pattern coding method as a method for obtaining a high-resolution three-dimensional shape. The pattern coding method attempts to achieve the same resolution as the spatial coding method by coding the slit pattern light to be projected (a method of specifying the order using the order of adjacent light projections). . However, there are theoretically pattern coding methods that have the same resolution as the spatial coding method, but in reality, it is very difficult to determine the order of projection rays from an image. rare.

  The present invention has been made in view of such problems, and an object thereof is to provide a simplified configuration in a three-dimensional shape measurement method and a three-dimensional shape measurement apparatus.

  In order to achieve the above object, the three-dimensional shape measurement method according to claim 1 irradiates a measurement object with irradiation light of a predetermined light intensity distribution pattern and detects reflected light according to the principle of triangulation. In the three-dimensional shape measurement method used for illumination when irradiating an object, irradiation light that irradiates a measurement object onto a pattern structure in which filters that absorb light of one or more different wavelength bands are arranged in a plurality of patterns And a plurality of steps of converting the irradiation light into irradiation light arranged in a plurality of patterns.

  The three-dimensional shape measurement apparatus according to claim 2 illuminates a measurement object by irradiating the measurement object with irradiation light having a predetermined light intensity distribution pattern and detecting the reflected light based on the principle of triangulation. In the three-dimensional shape measuring apparatus used for the measurement, the illumination light conversion means includes a pattern structure in which filters that absorb light of one or more different wavelength bands are arranged in a plurality of patterns, and the illumination light conversion means performs measurement. By transmitting the irradiation light for irradiating the object, the irradiation light is converted into irradiation light arranged in a plurality of patterns.

  A third aspect of the present invention is the three-dimensional shape measuring apparatus according to the second aspect, wherein two or more illumination light converting means are provided.

  A fourth aspect of the invention is the three-dimensional shape measuring apparatus according to the second or third aspect, wherein the illumination light converting means has moving means that can move in parallel to the measurement object.

  The invention according to claim 5 is the three-dimensional shape measuring apparatus according to any one of claims 2 to 4, wherein the irradiation light arrayed in a plurality of lattice patterns by the illumination light converting means is in a region by wavelength. When each is separated, at least one illumination light converting means separates the regions into stripes.

  A sixth aspect of the present invention is the three-dimensional shape measuring apparatus according to any one of the second to fifth aspects, wherein the irradiation light arrayed in a plurality of lattice patterns by the illumination light converting means is applied to a certain plane. One or more means for converting the irradiation light so that the irradiation light does not exist in a region adjacent to the region where the projection light exists when the projection image when projected onto the screen is divided into regions by wavelength It is characterized by having.

  A seventh aspect of the invention is the three-dimensional shape measuring apparatus according to any one of the second to fifth aspects, wherein the irradiation light arranged in a plurality of patterns by the illumination light converting means is applied to a certain plane. Having one or more means for converting the irradiation light so that the area where the projection light does not exist and the area where the irradiation light exists are alternated when the projected image when projected is divided into regions by wavelength It is characterized by.

  The invention according to claim 8 is the three-dimensional shape measuring apparatus according to claim 2, wherein the illumination light conversion means is capable of adjusting the amount of irradiation light.

  According to the present invention, one pattern structure can be simplified and the creation of the pattern structure can be facilitated by projecting the irradiation light through the pattern structure in which a plurality of patterns are arranged. Can do.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of the three-dimensional shape measuring apparatus 100.
The three-dimensional shape measuring apparatus 100 includes a light projecting unit 101, a first illumination light conversion unit 102, a second illumination light conversion unit 103, a moving device 104, and an imaging unit 300 having an imaging switch 301.

  The illumination light emitted from the light projecting unit 101 (point light source) is structured by the first illumination light conversion unit 102, restructured by the second illumination light conversion unit 103, and then projected onto the subject 200. The first illumination light conversion unit 102 and the second illumination conversion unit 103 are arranged in parallel, and the imaging unit 300 captures a state in which structured illumination light emitted from the light projecting unit 101 is projected onto the subject 200. can do. In addition, the positional relationship between the imaging unit 300 and the light projecting unit 101 is measured in advance, and the moving device 104 keeps the second illumination light conversion unit 103 parallel to the first illumination light conversion unit 102 and the first illumination. The light conversion unit 102 and the second illumination light conversion unit 104 can be moved in a direction that maintains the distance. When the shooting switch 301 is pressed, shooting starts.

Next, the processing operation of the three-dimensional shape measuring apparatus will be described with reference to FIG.
First, when the user presses the photographing button 301 (step S100), illumination light is emitted from the light projecting unit 101 (step S101). Next, the emitted illumination light passes through the first illumination light conversion unit 102 (step S102), and then passes through the second illumination light conversion unit 103 (step S103). The illumination light transmitted through the first and second illumination light conversion units is projected onto the subject 200, and the imaged moment is projected by the imaging unit 300 and stored (step S104).

  Next, it is determined whether or not the number of patterns has been photographed (step S105). If the specified number of images has not been taken (step S105 / NO), the process returns to step S101, and the second illumination light conversion unit 103 is moved by the moving device 104 by the specified amount. Further, when the number of patterns has been photographed (step S105 / YES), the three-dimensional shape restoration is performed using the prescribed number of images (step S106).

  As shown in FIG. 3, the portion irradiated with light from the light projecting unit 101 of the first illumination light converting unit 102 is a pattern mask having a rectangular parallelepiped shape. Further, the depth of the first illumination light conversion unit 102 (the direction from the light projecting unit 101 to the subject 200) is very thin.

  As shown in FIG. 3, it is composed of mask regions 400a to 400l, and the sizes of the mask regions are all equal. Each mask area transmits R (red) transmission component made from a component that transmits only the red wavelength, G (green) transmission component made from a component that transmits only the green wavelength, and transmits only the blue wavelength It is comprised from either B (blue) transmission component made from the component to do.

  When a CCD is used for the imaging unit 300, high-precision three-dimensional measurement is performed by setting the wavelength regions of the R, G, and B transmission components so as not to overlap according to the spectral sensitivity characteristics of the CCD. Can do. In the present embodiment, it is not necessary to strictly separate the wavelength regions of the three colors, and the three color components R, G, and B are separated by image processing. Table 1 shows transmission components assigned to each mask region of the first illumination light conversion unit 102.

Next, the second illumination light conversion unit 103 will be described.
The second illumination light conversion unit 103 is a pattern mask having a rectangular parallelepiped shape like the first illumination light conversion unit 102, and from the mask regions 500a to 500m as shown in FIGS. The mask areas are all equal in size. FIG. 4B is a shift of FIG. 4A to the right.

      Each mask region has an M (magenta) transmission component made up of components that transmit only the red and blue wavelengths in the R transmission component, the G transmission component, and the B transmission component, as in the first illumination light conversion unit 102, It consists of a Y (yellow) transmission component made from a component that transmits only red and green wavelengths, and a C (cyan) transmission component made from a component that transmits only green and blue wavelengths.

   At this time, each transmission component of R, G, B, C, M, and Y is configured to cut the same frequency as that of the first illumination light conversion unit 102, and Table 2 shows each of the second illumination light conversion unit 103. The transmission component assigned to the mask area is shown.

  The areas of the mask regions 400a to 400l of the first illumination light conversion unit 102 and the areas of the mask regions 500a to 500m of the second illumination light conversion unit 103 have a relationship as shown in FIG. That is, when the distance from the light projecting unit 101 (point light source) to the first illumination light converting unit 102 is d1, and the distance from the light projecting unit 101 to the second illumination light converting unit 103 is d2, the mask regions 400a to 400a. The vertical side and the horizontal side of the mask area between l and the mask areas 500a to 500m are set so that the relationship of d1: d2 is established. That is, the area ratio of the mask region is d1 squared: d2 squared.

  The moving device 104 can move the second illumination light conversion unit 103 while keeping the second illumination light conversion unit 103 and the first illumination light conversion unit 102 in parallel. Therefore, from the relationship between the sizes of the first illumination light conversion unit 102 and the second illumination light conversion unit 103, all of the light emitted from the light projecting unit 101 passes through the mask region 400a. There is a position that passes through 500a. Therefore, the 2nd illumination light conversion part 103 is moved to this position using the moving apparatus 104. FIG.

At that time, similarly, the light transmitted through the mask region 400b is transmitted through the mask region 500c, the light transmitted through the mask region 400c is transmitted through the mask region 500c, and the light transmitted through the mask region 400c is transmitted. It passes through the mask region 500d. in this way,
The position of the second illumination conversion unit 103 when the relationship when the light from the light projecting unit 101 passes through the first illumination light conversion unit 102 and the second illumination light conversion unit 103 is assumed to be POS1.

  Further, even when the second illumination conversion unit 103 in POS 1 is shifted rightward by one mask area (FIG. 4B), the above relationship is established, and the second illumination light conversion unit 103 at that time is established. Let POS2 be the position.

  When the second illumination light conversion unit 103 is in the position of POS1, when light having all visible light wavelength components is projected from the projection unit 101, the light passes through the mask regions 200a to 200l of the first illumination light conversion unit 102. The transmitted light passes through the mask region 500b of the second illumination light conversion unit 103. Illumination light emitted from the light projecting unit 101 passes through the mask region 400a to become only the R component, and passes through the mask region 500b to eliminate transmitted light.

  When the second illumination light conversion unit 103 is in the POS 1, the structured illumination light projected on the subject is shown in Table 3 when the correspondence between the mask regions is set as shown in FIGS. 3 and 4A. Shown in

  The first mask region and the second mask region in Table 3 are the mask region, the first transmission component, and the second transmission component of the first illumination light conversion unit 102 and the second illumination light conversion unit 103, respectively. It represents a transmission component that passes through one mask region and a second mask region. The illumination light is a result of taking AND of the first transmission component and the second transmission component when Table 3 is viewed in the vertical direction.

  Therefore, when the second illumination light conversion unit 103 is arranged at POS1, the illumination light structured as shown in Table 3 is projected onto the subject 300, and when the second illumination light conversion unit 103 is arranged at POS2. Illuminated light structured as shown in Table 4 is projected onto the subject 300.

Next, the minimum number of photographing times by the first illumination light conversion unit 102 and the second illumination light conversion unit 103 will be described.
The mask areas of the first illumination light conversion unit 102 and the second illumination light conversion unit 103 are designed so that the number of patterns is two. The number of patterns is obtained when the second illumination light conversion unit 103 is shifted rightward (leftward) by an integral multiple of the area by the moving device 104. Represents different structured illumination light types.

  In broad definition, the second illumination light conversion unit 103 is expanded to create an illumination light conversion unit in which the mask region 500a to the mask region are repeated a finite number of times, and the moving unit 104 shifts an integral multiple of the region. When the structured illumination light is made, the illumination light projected on the subject is not projected as the illumination light of Table 3 or Table 4. In this case, the number of patterns is counted twice. Of course, it is possible to increase the minimum number of times of photographing by changing the transmission components assigned to the mask areas 400a to 400l and the mask areas 500a to 500m.

  When photographing the subject 200, the second illumination light conversion unit 103 is arranged at the POS 1, and an image obtained by photographing the illumination light projected onto the subject 200 is set as an image 1, and then the second illumination An image obtained by arranging the light conversion unit in the POS 2 and photographing the illumination light projected onto the subject 200 is referred to as an image 2.

  Tables 3 and 4 show the structured illumination light patterns when photographing images 1 and 2. Therefore, the three-dimensional shape is restored using a commonly used spatial coding algorithm or the like.

[Second Embodiment]
The second embodiment is different from the first embodiment only in the illumination light structured by the first illumination light conversion unit 102 and the second illumination light conversion unit 103, and the other configurations are the same. . As shown in FIG. 6, the first illumination light conversion unit 102 includes an R transmission component made from a component that transmits only the red wavelength, a G transmission component made from a component that transmits only the green wavelength, and blue B transmission component made from a component that transmits only the wavelength of K and a K transmission component that does not transmit light. With these four types of mask regions, mask regions 600a to 600l are defined by a thick frame 601 in FIG. 6, and the mask region 500a includes a transmissive region K + a transmissive region R + a transmissive region K. Similarly, the mask region 500b includes It is composed of a transmission region K + a transmission region B + a transmission region K.

  As shown in FIGS. 7A and 7B, the second illumination light conversion unit 103 is an M transmission made from a component that transmits only red and blue wavelengths, as in the first illumination light conversion unit 102. It consists of a component, a Y transmissive component made from a component that transmits only red and green wavelengths, and a C transmissive component made from a component that transmits only green and blue wavelengths. At this time, the transmission components of R, G, B, C, M, and Y are created so as to cut the same frequency as the first illumination light conversion unit 102.

  Light having a red wavelength region that has been transmitted through the R transmissive component by the first illumination light conversion unit 102 passes through the G transmissive component or the B transmissive component by the second illumination light conversion unit 103, so that the illumination light is not transmitted to the subject 200. That is, the light emitted from the light projecting unit 101 is blocked as long as the first illumination light conversion unit 102 and the second illumination light conversion unit 103 do not pass the same transmission component.

  As shown in FIG. 7, the mask regions 700a to 700a-m have any of R, B, G, and K transmission components and are designed to have the same area. Similarly, the mask regions 700a to 700m in FIGS. 7A and 7B have any one of Y, G, C, B, M, and R transmission components and are designed to have the same area. In addition, the first illumination light conversion unit 102 and the second illumination light conversion unit 103 are made sufficiently thin with respect to the normal direction of the surface on which the mask regions 500a to ll and the mask regions 600a to 600m are arranged. To do.

  When the size, position, and transmission component of the first illumination light conversion unit 102 and the second illumination light conversion unit 103 are set as described above, and light having all visible light wavelength components is projected from the light projection unit 101. It becomes possible to show the following.

  All of the light transmitted from the light projecting unit 101 through the mask region 500a of the first illumination light conversion unit 102 is transmitted through the mask region 600b of the second illumination light conversion unit 103 only. Therefore, the illumination light from the light projecting unit 101 becomes only the R component by transmitting through the mask region 500a, and there is no transmitted light by making the mask region 600b equal. When this is set so that the positional relationship between the first illumination light conversion unit 102 and the second illumination light conversion unit is as shown in FIG. 6 and FIG. 7A, structured illumination light projected on the subject is obtained. Table 5 shows this.

  Here, the 1st field in Table 5 represents each field of the 1st illumination light conversion part 102 of FIG. Further, the second region represents each region of the second illumination light conversion unit 103 in FIGS. 7A and 7B. In addition, each transmission component corresponding to each mask region is a first transmission component for the first illumination light conversion unit 102 and a second transmission component for the second illumination light conversion unit. At this time, when the positional relationship between the first illumination light conversion unit 102 and the second illumination light conversion unit 103 is as shown in FIG. 6 and FIG. The corresponding transmission component is the second transmission component 1, and the structured illumination light actually projected onto the subject is the illumination light 1.

  Similarly, the case where the second illumination light conversion unit 103 is located at the position of FIG. 7B with respect to the position of the first illumination light conversion unit 102 (FIG. 6) by the first region of FIG. The illumination light structured at that time as the second region 2 is shown in Table 6 as illumination light 2.

[Third Embodiment]
In the third embodiment, unlike the first and second embodiments, the second illumination light conversion unit 103 is slid in the vertical direction and the pattern to be projected is switched for each shooting.
In the third embodiment, an illumination light conversion unit 900 shown in FIG. 8 is used.
The illumination light conversion unit 900 is installed at the position of the first and second illumination light conversion units 102 and 103 shown in FIG. The pattern portion 901 is a mask having a shape in which the patterns shown in FIGS. The pattern unit 901 is held at both ends by the pattern unit holding mechanism 902, and the light projecting unit 101, the illumination light converting unit, and the like so that the illumination light is projected at the position of the horizontal line drawn on the pattern unit holding mechanism 902. Set to the position.

  The pattern unit 901 includes a pattern holding unit 903, and the pattern unit 901 can be translated with respect to the pattern holding mechanism 902. The illumination light conversion unit 900 installs the upper mask pattern (the same mask pattern as that in FIG. 4A) so that light passes through during the first shooting, and the lower mask pattern during the second shooting. By sliding the pattern so that light passes through the mask pattern (the same mask pattern as in FIG. 4B), the same three-dimensional shape measurement as in the first embodiment can be performed.

  In addition, when the imaging unit has an AF (auto focus) function, an illumination light conversion unit that can project fine illumination light and an illumination light conversion unit that can project coarse illumination light according to the distance of the subject by AF, Can be switched.

It is the figure which showed the structure of the three-dimensional shape measuring apparatus in this embodiment. It is the flowchart which showed the processing operation of the three-dimensional shape measuring apparatus shown in FIG. It is the figure which showed the shape of the pattern mask of a 1st illumination light conversion part. FIG. 4A is a diagram showing the shape of the pattern mask of the second illumination light conversion unit, and FIG. 4B shows the pattern mask of FIG. 4A shifted to the right. It is the figure which showed the positional relationship of a light projection part, a 1st illumination light conversion part, and a 2nd illumination light conversion part. It is the figure which showed the shape of the pattern mask of the 1st illumination light conversion part in 2nd Embodiment. Fig.7 (a) is the figure which showed the shape of the pattern mask of the 2nd illumination light conversion part. FIG. 7B shows the pattern mask shown in FIG. 7A shifted to the right. It is the figure which showed the structure of the illumination light conversion part in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Three-dimensional shape measuring apparatus 101 Light projection part 102 1st illumination light conversion part 103 2nd illumination light conversion part 104 Moving apparatus 200 Subject 300 Imaging part 301 Shooting switch

Claims (8)

In the three-dimensional shape measurement method used for illumination when irradiating a measurement object with the principle of triangulation by irradiating the measurement object with irradiation light of a predetermined light intensity distribution pattern and detecting reflected light,
Transmitting the irradiation light that irradiates the measurement object to a pattern structure in which filters that absorb light of one or more different wavelength bands are arranged in a plurality of patterns;
A three-dimensional shape measuring method comprising a plurality of steps of converting the irradiation light into irradiation light arranged in a plurality of patterns. In the three-dimensional shape measurement device used for illumination when irradiating the measurement object according to the principle of triangulation by irradiating the measurement object with the irradiation light of the predetermined light intensity distribution pattern and detecting the reflected light,
Comprising illumination light conversion means comprising a pattern structure in which filters that absorb light of one or more different wavelength bands are arranged in a plurality of patterns;
A three-dimensional shape measuring apparatus, wherein the illumination light is converted into irradiation light arranged in a plurality of patterns by transmitting the illumination light for irradiating the measurement object to the illumination light conversion means.   The three-dimensional shape measuring apparatus according to claim 2, wherein the illumination light converting means includes two or more illumination light converting means.   The three-dimensional shape measuring apparatus according to claim 2 or 3, wherein the illumination light converting means includes a moving means capable of moving in parallel with the measurement object.       When the illumination light arranged in a plurality of patterns by the illumination light conversion means is separated for each region by wavelength, at least one illumination light conversion means separates the regions into stripes. Item 5. The three-dimensional shape measurement apparatus according to any one of Items 2 to 4.   When the projection light when the illumination light arranged in a plurality of patterns by the illumination light conversion unit is projected onto a certain plane is divided into regions by wavelength, the illumination light is irradiated on a region adjacent to the region where the projection light exists 6. The three-dimensional shape measuring apparatus according to claim 2, further comprising one or more means for converting the irradiation light so as to be a region in which no light exists.   A region where there is no projection light and a region where irradiation light exists when the projection image obtained by projecting the irradiation light arranged in a plurality of patterns by the illumination light conversion means onto a certain plane is divided by wavelength The three-dimensional shape measuring apparatus according to any one of claims 2 to 5, further comprising one or more means for converting the irradiation light so that and are alternately arranged.   The three-dimensional shape measuring apparatus according to claim 2, wherein the illumination light converting unit is capable of adjusting the amount of irradiation light.

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