JP7187330B2 - Shape measuring device, shape measuring system, and shape measuring method - Google Patents

Description

The present invention relates to a shape measuring device, a shape measuring system, and a shape measuring method.

Conventionally, as a device for measuring the bending diameter of an object to be measured (plate material, pipe material, bar material, etc.) that has been subjected to bending, three sets of light sources and CCD cameras arranged on both sides of the object to be measured, A bending diameter measuring device is known that includes coordinate calculation means for calculating x and y coordinates of three points on a curved side of an object to be measured (see Patent Document 1).

Each CCD camera has a lens that collects light from a light source and a linear array sensor that receives light through the lens. Each of the three sets of light sources and CCD cameras are arranged such that the y-coordinates of the three intersections of the plane from the light source to the linear array sensor and the curved side are specified in advance. The coordinate calculation means obtains a bright and dark image signal from the linear array sensor, and obtains the x-coordinate of each intersection position based on the binarized signal of the image signal.

JP-A-6-11324

However, in the bending diameter measuring device described in Patent Document 1, the bending diameter is measured based on the x and y coordinates of three points corresponding to the fixed position of the linear array sensor of each CCD camera. is limited, and it can only measure one curved side of the object to be measured. Moreover, if the linear array sensor is not fixed accurately at a predetermined position, an error will occur in the measurement result of the bending diameter.

An object of the present disclosure is to provide a shape measuring device, a shape measuring system, and a shape measuring method that can measure the shape of an object simply and accurately.

A shape measuring device according to an aspect of the present disclosure measures a side view shape of an object to be measured that has been bent while being fed in a feed direction. The shape measuring device includes a light source, a stereo camera, and a shape measuring section. The light source projects a predetermined line segment onto the main surface of the object to be measured. A stereo camera has a plurality of cameras that are installed separately from each other and capture images of the main surfaces of the object to be measured. The shape measuring unit acquires three-dimensional coordinates of a point group representing a predetermined line segment based on the images captured by each of the plurality of cameras, and determines the shape of the object to be measured based on the three-dimensional coordinates of the point group. A side view shape of a region where a predetermined line segment is projected is measured. The predetermined line segments each extend in the feeding direction and include two or more line segments different from each other.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a shape measuring device, a shape measuring system, and a shape measuring method capable of simply and accurately measuring the shape of an object to be measured.

1 is a schematic diagram showing the configuration of a shape measuring system according to an embodiment; FIG. FIG. 4 is a schematic diagram showing a state of projection of first and second line segments onto the main surface of the object to be measured; It is a schematic diagram for demonstrating the measuring method of the side view shape of to-be-measured object. 4 is a flowchart for explaining a process of measuring a side view shape of an object to be measured;

A shape measuring system 100 according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a shape measuring system 100 according to an embodiment.

A shape measuring system 100 includes a bending device 10 and a shape measuring device 20 . The bending device 10 bends the object W to be measured while sending the object W to be measured in the feed direction Df. A plate material, a tube material, a bar material, or the like can be used as the object W to be measured. The object W to be measured according to this embodiment is assumed to be a plate material. The shape measuring device 20 measures the side view shape of the object W bent while being fed in the feed direction Df.

(Bending device 10)
The bending device 10 has a first side roll 11 , a second side roll 12 , a top roll 13 and a feed amount detection section 14 . The first and second side rolls 11, 12 are examples of "a pair of side rolls" according to the present disclosure.

The first side roll 11 is formed in a cylindrical shape. The first side roll 11 rotates about the axis 11a in the feeding direction Df. The second side roll 12 is formed in a cylindrical shape. The second side roll 12 is arranged parallel to the first side roll 11 . The second side roll 12 rotates about the axis 12a in the feeding direction Df.

The top roll 13 is formed in a cylindrical shape. The top roll 13 is arranged parallel to each of the first and second side rolls 11 and 12 . The top roll 13 rotates about the axis 13a in the feeding direction Df. The top roll 13 is provided so as to be separable and contactable with respect to a line segment La connecting the axis 11 a of the first side roll 11 and the axis 12 a of the second side roll 12 . The top roll 13 may be vertically movable with respect to the line segment La.

By sending the object W to be measured in the feeding direction Df with the top roll 13 pressed against the object W placed between the pair of side rolls 11 and 12 and the top roll 13, the object W to be measured is rolled. It is bent into a shape.

The feed amount detection unit 14 detects the feed amount of the workpiece W fed in the feed direction Df. The feed amount detector 14 includes a roller 14a and a rotary encoder 14b. The roller 14a rotates together with the object W sent in the sending direction Df. The rotary encoder 14b detects the amount of rotation of the roller 14a. The rotary encoder 14 b outputs the detected amount of rotation of the roller 14 a to the shape measuring device 20 .

(Shape measuring device 20)
The shape measuring device 20 includes a light source 21 , a stereo camera 23 and a shape measuring section 25 .

The light source 21 has a first laser light source 21a and a second laser light source 21b. As shown in FIG. 2, the first laser light source 21a projects a first line segment L1 onto the main surface Ws of the object W to be measured, and the second laser light source 21b projects a second line segment L1 onto the main surface Ws of the object W to be measured. Project L2. The first and second line segments L1 and L2 are examples of "predetermined line segments" according to the present invention. The first and second line segments L1 and L2 are line segments that extend in the feeding direction Df and are different from each other. In the present embodiment, each of the first and second line segments L1 and L2 extends in the feed direction Df and in the width direction perpendicular to the feed direction Df. In this embodiment, the first and second line segments L1 and L2 intersect at the intersection point M1.

The stereo camera 23 has a first camera 23a and a second camera 23b. The first and second cameras 23a, 23b are installed apart from each other. The first and second cameras 23a, 23b are arranged equidistant from the main surface Ws. The first and second cameras 23a and 23b capture equidistant projection images of the main surface Ws of the object W to be measured, respectively. The first camera 23a outputs first equidistant projection image data representing the captured equidistant projection image to the shape measuring unit 25, and the second camera 23b outputs the second equidistant projection image data representing the captured equidistant projection image. The data are output to the shape measuring section 25 .

The shape measurement section 25 has a light source control section 26 , a camera control section 27 , a three-dimensional coordinate acquisition section 28 and an image processing section 29 .

The light source control unit 26 causes the light source 21 to project the first and second line segments L1 and L2 onto the main surface Ws of the object W to be measured every time the object W is fed by a predetermined amount in the feeding direction Df. The camera control unit 27 causes the stereo camera 23 to capture first and second equidistant projection images each time the light source 21 projects the first and second line segments L1 and L2 onto the main surface Ws of the object W to be measured. In the present embodiment, the object W to be measured is temporarily stopped each time the object W to be measured is fed in the feeding direction Df by a predetermined amount.

The three-dimensional coordinate acquisition unit 28 acquires the first and second equidistant projection image data from the stereo camera 23 . The three-dimensional coordinate acquisition unit 28 acquires three-dimensional coordinates of points indicating the first and second line segments L1 and L2 based on the first and second equidistant projection image data. At this time, the three-dimensional coordinate acquisition unit 28 can extract the lines with the highest brightness on the image as the first and second line segments L1 and L2. The three-dimensional coordinates of this point cloud are defined by the x-, y-, and z-axes shown in FIG. The z- axis corresponds to the feeding direction Df of the workpiece W in plan view. The x- axis corresponds to the width direction of the object W to be measured. The width direction is a direction perpendicular to the feed direction Df when the main surface Ws of the object W is viewed from above. The y- axis corresponds to a straight line that is parallel to the optical axis of the first camera 23a and the optical axis of the second camera 23b and located in the middle of them.

The image processing unit 29 obtains the minimum and maximum values of the z -coordinate and the minimum and maximum values of the x- coordinate by referring to the three-dimensional coordinates of the point group representing the first and second line segments L1 and L2. do. The image processing unit 29 determines whether two points included in the point group exist on the scanning line by scanning in the z -axis direction from the minimum value to the maximum value of the z- coordinate. The image processing unit 29 repeats scanning in the z- axis direction until the x- coordinate reaches the maximum value from the minimum value. Thereby, the image processing unit 29 identifies a portion where only one point exists on the scanning line. In this embodiment, since the first and second line segments L1 and L2 are X-shaped, the point where only one point exists on the scanning line is the intersection point M1.

The image processing unit 29 sets the Z- axis, X -axis, and Y -axis passing through the intersection point M1. The Z -axis, X -axis and Y -axis respectively correspond to the feed direction Df, the width direction and the optical axis direction.

The image processing unit 29 projects the point cloud onto the Z - X plane without rotating it around the X axis, and calculates the variation of the point cloud on the Z - X plane. Subsequently, the image processing unit 29 rotates the point cloud around the X axis by a certain angle and then projects it onto the Z - X plane again to calculate the variation of the point cloud on the Z - X plane. The rotation is repeated until it rotates about 100 degrees, and the angle around the X axis when the variation on the Z - X plane takes the minimum value is stored.

In addition, the image processing unit 29 projects the point group onto the Z - Y plane without rotating it around the Y axis, and calculates the variation of the point group on the Z - Y plane. Subsequently, the image processing unit 29 rotates the point group around the Y axis by a certain angle and then projects the point group onto the Z - Y plane again to calculate the variation of the point group on the Z - Y plane. The rotation is repeated until it rotates about 100 degrees, and the angle around the Y axis when the variation on the Z - Y plane takes the minimum value is stored.

The image processing unit 29 determines the angle around the X -axis when the variation on the Z - X plane takes the minimum value and the angle around the Y -axis when the variation on the Z - Y plane takes the minimum value. , and rotate the point cloud to find the point cloud that minimizes the variation on each plane. The point group obtained in this manner is a point group obtained by viewing the original point group from the side, as shown in FIG. Then, the image processing unit 29 projects the side-viewed point group onto the Z - X plane to measure the side-view shape of the point group. Subsequently, the image processing unit 29 measures the curvature of the point cloud based on the side view shape of the point cloud. The shape of this point group is the side view shape of the area in the feeding direction (hereinafter referred to as "line segment projection area") on which the first and second line segments L1 and L2 are projected on the object W to be measured. Also, the curvature of the point group is the curvature of the segment projection area of the object W to be measured.

As described above, the image processing unit 29 measures the side-view shape and curvature of the line segment projection area of the object W to be measured each time the object W to be measured is fed by a predetermined amount in the feeding direction Df. Then, the image processing unit 29 can connect two or more side-view shapes of the line segment projection regions in the feeding direction Df. At this time, the image processing unit 29 refers to the feed amount of the workpiece W acquired from the feed amount detection unit 14, and accurately grasps the connection points of the side view shapes of two or more line segment projection regions. can be done.

(Shape measurement method)
Next, a shape measuring method in the shape measuring device 20 will be described with reference to the drawings. FIG. 4 is a flow chart for explaining the process of measuring the side view shape of the object W to be measured.

In step S<b>1 , the light source control unit 26 causes the light source 21 to project the first and second line segments L<b>1 and L<b>2 onto the main surface Ws of the object W to be measured when the object W to be measured stops feeding.

In step S2, the camera control unit 27 causes the stereo camera 23 to capture first and second equidistant projection images.

In step S3, the three-dimensional coordinate acquisition unit 28 creates point groups representing the first and second line segments L1 and L2 based on the first and second equidistant projection image data representing the first and second equidistant projection images. Get 3D coordinates.

In step S4, the image processing unit 29 measures the side view shape of the line segment projection area of the object W onto which the first and second line segments L1 and L2 are projected, based on the three-dimensional coordinates of the point group. do. Specifically, the step of measuring the side view shape of the line segment projection area includes a step of projecting the point group onto the Z - X plane and the Z - Y plane set on the object W to be measured, and rotating the point group. and obtaining a point group that minimizes the variation on the Z - X plane and the Z - Y plane; and measuring the side view shape of the point group that minimizes the variation.

(feature)
The shape measuring apparatus 20 according to this embodiment measures the side view shape of the object W bent while being fed in the feed direction Df. The shape measuring device 20 includes a light source 21 , a stereo camera 23 and a shape measuring section 25 . The light source 21 projects the first and second line segments L1 and L2 onto the main surface Ws of the object W to be measured. The stereo camera 23 has first and second cameras 23a and 23b that are installed apart from each other and take images of the main surface Ws of the object W to be measured, respectively. Based on the first and second equidistant projection images captured by the first and second cameras 23a and 23b, respectively, the shape measurement unit 25 measures a three-dimensional point group representing the first and second line segments L1 and L2. Coordinates are obtained, and the side view shape of the line segment projection area of the object W onto which the first and second line segments L1 and L2 are projected is measured based on the three-dimensional coordinates of the point group. Each of the first and second line segments L1 and L2 is a line segment that extends in the feed direction Df and is different from each other.

In the shape measuring apparatus 20 according to the present embodiment, the first and second line segments L1 and L2, which extend in the feed direction Df and are different from each other, are used. The shape can be measured simply and accurately. Therefore, according to the shape measuring apparatus 20 according to the present embodiment, it is possible to accurately grasp the degree of bending applied to the line segment projection region regardless of whether the bending is performed or the bending is performed. Further, according to the shape measuring apparatus 20 according to the present embodiment, not only can the side view shape be automatically measured in a short time, but also safety can be ensured compared to, for example, a case in which an operator visually confirms the degree of bending. can.

In this embodiment, the first and second line segments L1 and L2 include an intersection point M1 where they intersect. Therefore, as described above, the point group indicating the first and second line segments L1 and L2 can be rotated around the X -axis and the Y- axis with reference to the intersection point M1. can be grasped easily and quickly.

In the present embodiment, the shape measuring unit 25 can connect two or more side view shapes of the line segment projection area in the feeding direction. Therefore, even if the object W to be measured is long, the overall side view shape of the object W to be measured can be measured.

(Other embodiments)
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention.

In the above embodiment, as an example of the "predetermined line segment", the first and second line segments L1 and L2 that extend in the feed direction Df and the width direction and intersect in an X shape are cited, but the present invention is not limited to this. . The "predetermined line segment" may include two or more line segments each extending in the feeding direction Df and different from each other. Therefore, the "predetermined line segment" may include two line segments extending parallel to the feeding direction Df and separated from each other. In addition, two or more line segments included in the "predetermined line segment" may not be straight lines, or may be connected to form substantially one line segment. Therefore, the "predetermined line segment" may be circular, elliptical, V-shaped, polygonal, wavy, zigzag, or any other complex shape. Note that when the "predetermined line segment" is substantially one line segment such as a circle, only one light source may be provided.

In the above-described embodiment, the "predetermined line segment" is projected onto the convex main surface of the two main surfaces of the object W to be measured. may be

In the above-described embodiment, the bending device 10 has a roller-type rotary encoder as the feeding amount detection unit 14, but the present invention is not limited to this. As the feed amount detection unit 14, for example, a laser light Doppler type speed sensor can be used.

Although the stereo camera 23 has two cameras in the above embodiment, it may have three or more cameras. The stereo camera 23 means a camera capable of obtaining information in the depth direction using parallax, and may have a plurality of cameras. A plurality of cameras constituting the stereo camera 23 need not be housed in one housing.

In the above embodiment, the first camera 23a and the second camera 23b of the stereo camera 23 output equidistant projection images, but the outputs may be perspective projection images.

100 Shape measurement system 10 Bending device 11 First side roll 12 Second side roll 13 Top roll 14 Feeding amount detection unit 20 Shape measurement device 21 Light source 23 Stereo camera 25 Shape measurement unit 26 Light source control unit 27 Camera control unit 28 Three-dimensional coordinates Acquisition unit 29 Image processing unit W Object to be measured Ws Principal surface L1 First line segment L2 Second line segment Df Feed direction

Claims (5)

A shape measuring device for measuring a side view shape of an object bent while being fed in a feeding direction,
a light source that projects a predetermined line segment onto the main surface of the object to be measured;
a stereo camera having a plurality of cameras that are installed apart from each other and respectively capture the main surfaces of the object to be measured;
a shape measuring unit that measures a side-view shape of a region of the object on which the predetermined line segment is projected , based on images captured by the plurality of cameras;
with
The predetermined line segments each extend in the feeding direction and include two or more different line segments,
The shape measuring unit projects the point group indicating the predetermined line segment onto a plane set on the object to be measured, and rotates the point group to minimize variations on the plane. measuring the side view shape of
Shape measuring device. the predetermined line segment includes an intersection point where the two or more line segments intersect;
The shape measuring device according to claim 1. The shape measuring unit connects two or more of the side view shapes of the projected area in the feeding direction,
The shape measuring device according to claim 1 or 2. It has a pair of side rolls and a top roll that is separable and contactable with respect to a line segment connecting the respective axes of the pair of side rolls, and feeds between the pair of side rolls and the top roll in the feeding direction. a bending device for bending an object to be measured;
a shape measuring device for measuring a side view shape of the object bent by the bending device;
with
The shape measuring device is
a light source that projects a predetermined line segment onto the main surface of the object to be measured;
a stereo camera having a plurality of cameras that are installed apart from each other and respectively capture the main surfaces of the object to be measured;
a shape measuring unit that measures a side-view shape of a region of the object on which the predetermined line segment is projected , based on images captured by the plurality of cameras;
has
The predetermined line segments each extend in the feeding direction and include two or more different line segments,
The shape measuring unit projects the point group indicating the predetermined line segment onto a plane set on the object to be measured, and rotates the point group to minimize variations on the plane. measuring the side view shape of
Shape measurement system. A shape measuring method for measuring a side view shape of an object bent while being fed in a feed direction,
a step of projecting a predetermined line segment onto the main surface of the object to be measured;
A side view of a region of the object to be measured on which the predetermined line segment is projected , based on images captured by a plurality of cameras installed separately from each other and each capturing a principal surface of the object to be measured. measuring the shape;
with
The predetermined line segments each extend in the feeding direction and include two or more different line segments,
The step of measuring the side view shape includes:
a step of projecting a point group indicating the predetermined line segment onto a plane set on the object to be measured;
A step of obtaining a point cloud that minimizes variation on the plane by rotating the point cloud;
a step of measuring a side view shape of the point cloud that minimizes the variation;
including,
Shape measurement method.

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