JPH04181108A - Method for recognizing three-dimensional shape - Google Patents

Abstract

PURPOSE:To enable an imaginary image to be eliminated positively and a normal shape to be recognized by changing an angle which is formed by an optical axis and a slit light by moving a camera when two or more images are taken. CONSTITUTION:A slit light 2 is projected from a slit light generation device 1 to an object to be measured 7, reflection light which is subjected to irregular reflection on a surface of the object to be measured 7 is received by a camera 3, and the image is sent to a real image/imaginary image judging equipment 5 through an image take-in equipment 4 for checking to see if there are two or more images. If there are two or more images, an imaginary image (regular reflection light) is included in the image so that it is not adopted as a data for operation 6 and the camera 3 is moved in a direction for preventing the imaginary image from being observed by a camera traveling device 9. Namely, when an angle formed by an observation direction of a camera 3 and an irradiation direction of a slit light 2 is converted from theta1 to theta2, the camera 3 deviates from reflection direction of the regular reflection light so that only an irregular reflection light (real image) enters the camera 3, thus enabling only a real image without any imaginary image to be observed and a shape to be recognized accurately.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a three-dimensional shape recognition method using optical cutting method.
In particular, it is designed to reliably detect and remove virtual images.

<Prior Art> In the field of machine tools, it may be necessary to recognize three-dimensional shapes in order to perform copying or to prevent collisions, or for mold processing equipment.

Optical sectioning is one method of non-contact shape recognition. This method involves irradiating a measurement object with slit light and determining the coordinates of the measurement object from the diffusely reflected image.

A conventional three-dimensional shape recognition device using this optical cutting method is shown in FIG. As shown in the figure, a slit beam 2 is emitted from a slit beam generator 1 onto an object to be measured 7 placed on a table 8.
is irradiated. The slit light generator 1 is placed above the table 8, and the slit light 2 is substantially perpendicular to the table 8. The slit light generating device 1 can be moved in a direction perpendicular to the parallel direction of the slit light 2.

On the other hand, the camera 3 is installed obliquely above the table 8, and photographs an optical image formed by irradiation with slit light. Image data corresponding to the image taken by this camera 3 is captured by an image capture device 4, and the image data is computed by a coordinate calculator 6 so that the shape of the object to be measured 7 can be recognized.

The method of calculating coordinates by the coordinate calculator 6 is shown in Fig. 3(a) (
b) (C) (Explain with reference to (branch). However,
As shown in FIGS. 3(a) and 3(b), the coordinate axes are such that the surface of the table 80 is the x-y plane, and the two axes are vertically above the x-y plane. Further, the irradiation direction of the slit light 2 is set to two directions, and the observation direction of the camera 3 is set diagonally upward in the y-axis direction (at an angle of θ from the Z-axis). In other words, the angle between the irradiation direction of the slit light 2 and the optical axis of the camera 3 is θ.

As shown in FIG. 3(C)(d), the slit light 2
Since it coincides with the −X plane, the slit light 2 is expressed by the following formula %. Furthermore, the magnification M at the coordinate origin 0, which is a distance from the lens center O° of the camera 3, is expressed by the following formula.

M=Δ−=B=L・−・(2) A, B, f However, A s B e is the coordinate origin, that is, the X direction at the distance, and the radius in the screen where the radiation A and B seen from the X direction are captured. It is the width.

Here, as shown in Figure 4, the coordinates in the image are α
, β, the photographing direction in the y-x plane corresponding to these coordinates is expressed by the following formula.

By substituting the above equation (11) into the above equation (3), the biaxial coordinates of the cutting line of the slit light can be found.

2・-1'' Hatsu 2111...(4) Lsxnθ+MαCOSθ Similarly, the X coordinate of the cutting line of the slit light is determined as follows.

L-zsuCOSθ (41 (By using formula 51, calculate the two coordinates and xM mark, and perform this calculation on the entire object to be measured, the three-dimensional shape can be recognized.

<Problems to be Solved by the Invention> As described above, in the three-dimensional shape recognition method using the light cutting method, the slit light 2 is irradiated onto the measurement object 7, the diffusely reflected light is imaged by the camera 3, and the image is This is to find the coordinates of the object to be measured, but depending on the material and shape of the object to be measured 7, specularly reflected light may be observed, so a virtual image may be observed in addition to the real image, or the virtual image may be more accurate than the real image. may be strongly observed.

For example, as shown in FIG. 5, if the measurement object 7 is made of a material with high reflectance and has a slope with an inclination angle φ of around θ/2 with respect to the horizontal, the specular reflection light of the slit light from the slope is reflected by the camera. 3, and a virtual image was generated.

In such cases, in the past, it was not possible to distinguish between the virtual image and the real image, resulting in errors in shape recognition.

The present invention has been made in view of the above-mentioned prior art,
It is an object of the present invention to provide a three-dimensional shape recognition method that can reliably detect and remove virtual images in three-dimensional shape recognition using a light cutting method.

Means for Solving the Problems> The configuration of the present invention to achieve such an object is to irradiate a slit light from a slit light generator toward an object to be measured, and to capture the reflected light of the slit light from the object to be measured by a camera. The reflected light taken by the camera is processed to obtain the image coordinates, and the image coordinates, the coordinates of the slit light position, the angle θ between the slit light and the optical axis of the camera, and the specifications of the camera lens are calculated. In a three-dimensional shape recognition method that recognizes the three-dimensional shape of a measurement target based on The camera is characterized in that when an image is taken at a moved camera position by changing the angle θ, it is determined to be a real image.

<Operation> When a measurement object with a high reflectance is irradiated with slit light from a certain angle, the specularly reflected light enters the camera, and a virtual image may be captured in addition to the real image.

For example, when the inclined surface of the object to be measured forms an angle φ (=θI/2) with respect to the horizontal plane as shown in Fig. 5, a slit light is irradiated from vertically above and an angle of θ1 is set to the slit light. When observed with a camera from the same direction, specularly reflected light enters the camera, and a virtual image is observed in addition to the real image.

Therefore, by moving the camera and changing the angle between the optical axis of the camera and the slit light from θ1 to 02, the specularly reflected light no longer enters the camera, and therefore no virtual image is observed.

<Examples> The present invention will be described in detail below with reference to examples shown in the drawings.

FIG. 1 shows an embodiment of the present invention. The embodiment shown in the figure is the same as the conventional three-dimensional shape recognition device shown in FIG.

That is, the object to be measured 7 is placed on the table 8, and the slit light generator 1 is suspended above the table 8. The slit light generator 1 irradiates the measurement object 7 with the slit light 2 from vertically above, and is movable in a direction parallel to the table 8 by a moving mechanism (not shown).

A camera 3 for observing the reflected light of the object to be measured 7 is supported by a camera moving device 9, and the camera moving device 9 can move the camera 3.

Therefore, when the camera 3 is moved by the camera moving device 9, the angle θ between the irradiation direction of the slit light and the optical axis of the camera 3 changes from θ1 to θ2.

Image data corresponding to the image taken by this camera 3 is captured by an image capture device 4, and the image data is computed by a coordinate calculator 6 so that the shape of the object to be measured 7 can be recognized.

A real image/virtual image discriminator 5 is interposed between the image capture device 4 and the coordinate calculator 6, and the real/virtual image discriminator 5 determines whether two or more images exist in the image captured by the image capture device 4. to judge.

Therefore, when the slit light generator 1 projects the slit light 2 onto the object to be measured 7, the slit light 2 is diffusely reflected on the surface of the object to be measured 7, and the reflected light is received by the camera 3.

The image received by the camera 3 is captured by the image capturing device 4, and the real/virtual image determining device 5 determines whether or not there are two or more images in the image captured by the image capturing device 4.

When the real/virtual image determiner 5 determines that there are two or more images, this means that the image includes a virtual image, and in this case, it is not adopted as data to be calculated by the coordinate calculator 6.
The camera 3 is moved by the camera moving device fi19 in a direction where the virtual image is not observed.

For example, as shown in FIG. 5, the measurement object 7 is made of a material with high reflectance, and the inclination angle ψ with respect to the horizontal plane is θ1/
2, the specularly reflected light of the slit light 2 enters the camera 3, and a virtual image is observed in the image capture device 4 in addition to the real image.

However, the optical axis of camera 3 and the irradiation direction of slit light 2 are θ1
shall form an angle of

Therefore, if the camera 3 is moved by the camera moving device 9 so that the angle formed between the observation direction of the camera 3 and the irradiation direction of the slit light 2 becomes from 01 to θ, the camera 3 is moved so that the specularly reflected light is not reflected. Therefore, the specularly reflected light does not enter the camera 3, but only the diffusely reflected light enters the camera 3.

Therefore, since there are no more than two images of the reflected light captured by the camera 3 after the camera 3 has been moved, the real/virtual image judger 5 judges that the reflected light is only a real image, and that image is sent to the coordinate calculator. Sent to 6.

The coordinate calculator 6 calculates the two coordinates and the X coordinate based on the above-mentioned formula (4) (51), but in these formulas, Lt and θ2 after the camera movement are used instead of θ. is the distance between the lens center and the coordinate origin after camera movement.

Note that when no specularly reflected light is incident on the camera 3 and no virtual image is generated, the camera 3 is not moved and the LI before moving the camera is
+01 to f41 (used in formula 51.

When the coordinate calculator 6 finishes calculating the two coordinates and the X coordinate, the camera 3 is returned to its original position by the camera moving device 9.

In this way, in this embodiment, when the specularly reflected light from the measurement object 7 enters the camera 3, the camera 3 is moved,
Since specularly reflected light is prevented from entering the camera 3, only a real image without a virtual image can be observed, thereby allowing accurate shape recognition.

In this embodiment, the camera moving device C9 and the real image/virtual image judge 5 are used, but the structure is not limited to these and other structures may be used as long as they have equivalent functions. .

<Effects of the Invention> As described above in detail based on the embodiments, the present invention is capable of moving the camera and adjusting the angle of the camera when the specularly reflected light of the slit light from the object to be measured is incident on the camera. Since the angle between the optical axis and the direction of the slit light is changed, specularly reflected light from the object to be measured does not enter the camera. Therefore, even if the object to be measured has a high reflectance, it is possible to reliably remove the virtual image and accurately recognize the shape.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a device used in a three-dimensional shape recognition method according to an embodiment of the present invention, FIG. 2 is a perspective view of a conventional three-dimensional shape recognition device, and FIG. b) are each x
-y plane, zy plane explanatory diagram, Figure 3 (C) (d)
are the z-y plane and Z of the conventional three-dimensional shape recognition method, respectively.
FIG. 4 is an explanatory diagram of the coordinates within the camera, and FIG. 5 is an explanatory diagram showing the relationship between the slit light and the optical axis of the camera. In the drawings, 1 is a slit light generator, 2 is a slit light, 3 is a camera, 4 is a Wi image capture device, 5 is a real/virtual image judge, 6 is a coordinate calculator, 7 is an object to be measured, 8 is a table, and 9 is a camera It is a mobile device. ! Slit 9 generator (C α, β: Coordinates in the image Figure 3 Figure 4! Slit 9 generator

Claims (1)

[Claims] A slit light generator emits slit light toward the object to be measured, and the reflected light of the slit light from the object to be measured is photographed by a camera, and the reflected light photographed by the camera is image-processed to obtain image coordinates. , in the three-dimensional shape recognition method for recognizing the three-dimensional shape of the object to be measured based on the image coordinates, the coordinates of the position of the slit light, the angle θ between the slit light and the optical axis of the camera, and the specifications of the camera lens. When two or more images are taken by a camera, the angle θ between the optical axis of the camera and the slit light is changed by moving the camera, and one image is taken at the moved camera position. , a three-dimensional shape measurement method characterized by determining this as a real image.