JP3201297B2 - Coil position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil position detecting device applied to an unmanned operation of an overhead crane in a coil yard of a steelworks.

[0002]

2. Description of the Related Art There are the following (1) to (3) as conventional coil position detecting devices of this type. (1) Detection method based on two-dimensional (luminance) image: This method is described in, for example, Japanese Patent Application No. 63-31215, "Development of a hot rolled product (coil) position detection device for an automatic warehouse crane (7th industry image sensing technology) Symposium) "and the like. In this detection method, a coil is illuminated by a projector, the reflected light is imaged by, for example, a CCD camera, and the coil position is detected from the luminance distribution of the reflected light. (2) Method using slit light: This method has been proposed in, for example, Japanese Patent Application Laid-Open No. 3-162395. In the method proposed here, one slit light is irradiated in each of the radial direction and the width direction of the coil, and the slit light is photographed by two television cameras. The center position and width are required. (3) Parallel movement method of a plurality of distance meters: This method has been proposed in, for example, Japanese Patent Application Laid-Open No. 7-306032. In this method, a lightwave distance meter is mounted on the crane so that light or ultrasonic waves are emitted near the intersection of the vertical line passing through the center of the crane's hanging tool and the object, and the coil is measured based on the measurement result of the lightwave distance meter. And the presence or absence of a pre-existing object in the space above and below the coil to be lifted.

[0003]

The following problems are pointed out in the above-mentioned conventional coil position detecting device. (1) Detection method using two-dimensional (luminance) image: a) Environment resistance: In a luminance image, it is difficult to stably maintain the difference between the surface luminance level of the coil and the luminance level of the peripheral part for the following reasons. is there. -Fluctuation in luminance level due to disturbance light (difference in brightness in the factory day and night, reflection of indoor lighting on the coil, reflection of sunlight in the visual field) is large. -There is large variation in the brightness level of the coil due to differences in coil surface properties (reflectance / rust plating, color, packing material). -It is difficult to distinguish the coil from the floor (there are marks on the floor, white lines, etc.). b) Position measurement: Accurate position measurement is difficult due to a perspective effect (a two-dimensional image has a shape distortion due to a perspective effect).

(2) Method using slit light: a) Data reliability: The shape data in the width direction and the radial direction of the coil are measured with one slit light (light cutting line) each. , Data reliability is low. In detecting the coil width, one end point on the left and right is taken as the edge position of the coil based on the shape of one light cutting line in the coil width direction. For example, when a light cutting line is missing, the end position cannot be measured accurately. In addition, since the shape in the coil radial direction is similarly measured using only one optical cutting line, when the optical cutting line is missing due to a difference in the reflectance of the coil packing material and the coil surface described above. Does not provide accurate data in the coil radial direction. b) Coil installation direction: In this system, a laser scanner (light source) and two television cameras are required, and the television cameras are installed separately from the laser scanner in the crane's traversing direction and running direction, respectively. And a large-scale configuration is required. Also, Japanese Patent Application Laid-Open No. 7-6351
No. 9 proposes a detection method in which measurement is performed by one laser scanner and one camera. However, this method limits the direction of the coil to one direction, and the direction of the coil is limited to one direction. The yard cannot be used as it is in a yard where the crane can traverse and travel in both directions.

(3) Parallel movement method of a plurality of distance meters: a) Large-scale device configuration: In this method, the height data of the coil surface is measured by moving a plurality of light wave distance meters in parallel. Since it is necessary to secure a moving range for the measurement area on the trolley, the apparatus configuration is inevitably large. b) Long moving time: The measuring time becomes long to translate a large device in parallel. c) Large measuring pitch (coarse): The measuring pitch is determined by the number of installed lightwave distance meters. However, since the lightwave distance meter is generally expensive, it is inevitable to use a small number of components in terms of cost, and the measurement is performed naturally. The pitch becomes coarse. d) Fixed measurement pitch: Since the installation position of the lightwave distance meter is fixed, it is not possible to select an optimum width according to the diameter of the coil to be measured. e) Expensive (installation of a plurality of distance meters): The cost of a device such as a moving mechanism is inversely proportional to the measurement pitch, and becomes expensive as the number of lightwave distance meters set increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can realize an apparatus with a high reliability and a simple structure. It is an object of the present invention to provide a coil position detecting device that enables measurement regardless of whether the coil is placed in any one of a direction and a running direction.

[0007]

A coil position detecting apparatus according to the present invention is mounted on an overhead crane for transporting coils, and emits a plurality of parallel slit lights obliquely to both directions of the coil width and diameter. A light projecting means for irradiating the coil upper surface while scanning; an image pickup means mounted on an overhead crane for imaging the coil upper surface irradiated with the slit light; Image processing means for extracting an image signal corresponding to the slit light,
A shape calculating means for obtaining three-dimensional shape data of the slit light irradiator for each of the plurality of slit lights based on an image signal corresponding to the extracted slit light; and a slit light irradiator for the plurality of slit lights. 3
The three-dimensional shape data of the slit light irradiating part for a plurality of slit lights is obtained by projecting the three-dimensional shape data in the width direction of the coil to obtain the radial center position of the coil and the coil diameter. And a coil calculating means for projecting the coil in the width direction and calculating the center position and the coil width of the coil in the width direction.

In the present invention, a light projecting means mounted on an overhead crane scans a plurality of parallel slit lights in a direction oblique to both directions of a coil width and a diameter to irradiate an upper surface of the coil. Then, the imaging means mounted on the overhead crane images the state. The image processing means performs image processing on the image pickup signal of the image pickup means, and extracts an image signal corresponding to the slit light from the image signal. The shape calculation means obtains three-dimensional shape data of the slit light irradiating portion of the coil for each of the plurality of slit lights. The coil calculating means includes a slit light irradiating unit for a plurality of slit lights.
The three-dimensional shape data of the slit light irradiating part for a plurality of slit lights is obtained by projecting the three-dimensional shape data in the width direction of the coil to obtain the radial center position of the coil and the coil diameter. Direction, the center position of the coil in the width direction and the coil width are obtained.

In the present invention, as described above, the three-dimensional shape of the coil is measured, and the discrimination between the coil and other areas (floor surface, trolley, etc.) is determined from the height and the shape. And robust measurement has been realized. Further, in the two-dimensional data, there is a shape distortion due to the perspective effect, but since the three-dimensional data is used, such a shape distortion can be removed. Also,
In the present invention, the entire shape of the coil is measured by multi-slit light using a plurality of slit lights, and therefore, robust measurement against disturbance is realized and reliability is improved. . Further, by using a plurality of data by the multi-slit light, the S / N is improved, and the coil position can be detected with improved performance.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram for explaining the measuring principle of the coil position detecting device according to the present invention. In the drawing, the DUT 2 is placed on a reference plane 1, and a television camera 10 is arranged on the reference plane 1 so that the central axis at the time of photographing is orthogonal. The slit light scanning devices 12 are arranged at different positions. The slit light scanning device 12 generates slit light 12a and scans it. The television camera 10 captures an image of the state, the captured signal is subjected to image processing by the image processing device 14, and the image signal is input to the shape calculation device 16 together with the projection angle θ from the slit light scanning device 12, and the shape calculation device At 16, the three-dimensional shape of the DUT 2 is measured. The coil operation device 18 obtains the position, width, and the like of the coil, which is the device under test 2, based on the measured three-dimensional shape.

Next, the coil position detecting device shown in FIG. 1 will be described in terms of a measuring method, a shape calculation principle, a direction of slit light, multi-slit formation, and generation of slit light. (A) Measurement method The optical system uses an optical system generally called a light section method. FIG. 2 is a diagram showing a configuration of the slit light scanning device 12. The slit light scanning device 12 first generates a slit light by scanning a laser spot light from the semiconductor laser 20 with a first scanning mirror 22 whose rotation is controlled by a drive motor 22a. At this time, the direction of the laser slit light is set in the y-axis direction in FIG. 1, and the projection position of the laser slit light in the x-axis direction in FIG. Control. At the same time, the projection angle θ of the scanning mirror 24 at this time is output to the shape calculation device 16 as an angle signal. Then, the irradiation pattern of the laser slit light 12 a is captured by the television camera 10 and input to the image processing device 14. The image processing device 14 performs image processing on an image pickup signal of the television camera 14 and extracts an image signal corresponding to the laser slit light from the image signal. The shape calculating device 16 calculates three-dimensional coordinates of the laser slit light from the position of the laser slit light of the extracted image signal and the laser projection angle θ at that time based on the principle of triangulation described later. .

(B) Principle of Shape Calculation The shape calculation device 16 calculates the three-dimensional coordinates of the laser slit light of the multi-slit light generated by the slit light scanning device 12 to obtain the entire shape of the DUT 2. . This shape calculation is based on a triangulation method. Laser slit light 12a is projected from the slit light scanning device 12 onto the measurement target (coil) 2 at a projection angle θ, and the state is imaged by the television camera 10. The height z (x ′, y ′) of the point (x ′, y ′) at which the laser light extracted from the image captured by the television camera 10 shines is
In consideration of the perspective effect of the television camera 10, the following relationship is established. z (x ′, y ′) = Z ₀ − {X ₀ − (1−z (x ′, y ′) / a) x} tan θ (x ′, y ′) (1) x ′: TV camera in position y on the reference plane of the captured image ': position on the reference plane of the image captured by the television camera X _0: x-coordinate Z ₀ of the laser beam scanning rotation axis: z of the laser beam scanning rotation axis Coordinate a: distance between the television camera and the reference plane θ: laser slit light projection angle If the above equation (1) is modified, the height z (x ′, y ′) of the point where the laser slit light hits becomes Is determined by

[0013]

(Equation 1)

The coordinates (x, y) on the three-dimensional coordinates of the point (x, y) where the laser beam is extracted on the image are given by the following equations. x = ｛1−z (x ′, y ′) / a｝ x ′ (3) y = ｛1−z (x ′, y ′) / a｝ y ′ (4) It is clear from the above description. As described above, the coordinates x ', y' on the image of the television camera 10 at the projection angle .theta.
It can be seen that the three-dimensional coordinates x, y, z of the detected point are obtained by the above equations (2), (3), (4). The above equations (3) and (4) have been corrected for the perspective effect that the closer to the TV camera 10 the larger the closer to the TV camera 10 because the distance between the DUT 2 and the TV camera 10 is finite. It can be seen that accurate shape detection cannot be performed only with a two-dimensional image.

(C) Direction of slit light In the above-described triangulation method, if the laser slit light is configured to be parallel to the y-axis direction on the reference plane 1, the shape on the same slit light is Can be calculated as the same projection angle θ. Therefore, the position (x ', y') of each point of the laser slit light on the image of the television camera 10 is obtained, and the three-dimensional coordinate (position / height) data of the portion hit by the slit light is calculated by the above equation. Can be obtained by

(D) Multi-slit formation With information of one laser slit light, only one section information of the measured object can be obtained. Therefore, first, the second scanning mirror 2
4 scans the first scanning mirror 22 and projects the laser slit light in the y-axis direction with the projection angle θ. The slit light is imaged by the television camera 10, and the shape on one section is calculated from the slit light image by the above-described calculation method. Next, the projection angle of the second scanning mirror 24 is changed from θ to a small angle Δθ.
, And again by the first scanning mirror 22, y
The laser slit light is projected in the axial direction. In this manner, the shape of a plurality of cross sections is measured one after another while changing the projection angle θ of the laser slit light, and the overall shape of the DUT 2 can be reconstructed by synthesizing the respective cross sectional shapes. The smaller the rotation pitch Δθ of the second scanning mirror 24, the better the shape resolution of the measured object. However,
On the other hand, the measurement time becomes longer.

(E) Generation of slit light In the above description, an example of generating laser slit light by scanning laser spot light has been described.
If a sufficient amount of light can be obtained, the same measurement can be performed by placing a rod lens or a cylindrical lens in the optical path of the laser spot light, generating laser slit light, and projecting this.

Now that the principle of shape measurement in the present invention has been clarified by the above description, the case where the optical system of FIG. 1 is arranged on an overhead crane will be described. FIG.
(A), (B), and (C) are a plan view, a front view, and a television camera 1 in which the optical system (the television camera 10 and the slit light scanning device 12) of FIG.
It is the figure which showed the image | video in the visual field of 0. As shown in FIG. 1A, the television camera 10 is disposed on the trolley 30 in a direction rotated by 45 ° with respect to the traversing direction, and the optical axis thereof is positioned vertically downward. The slit light scanning device 12 is installed on the x-axis of the television camera 10, and adjusts the direction of the slit light so as to be parallel to the y-axis direction of the television camera 10. The coil 3 to be measured is placed parallel to the traversing direction or running direction of the crane, and therefore, the attitude of the coil 3 captured by the television camera 10 is inclined (rotated) by 45 ° in the field of view. . In the yard, the coils 3 are arranged in either the traverse direction or the traveling direction of the crane, and the arrangement direction is grasped by a system computer managing the yard.

In this state, the slit light scanning device 12 irradiates the upper surface of the coil 3 while scanning the laser slit light,
A slit light image at an angle of 45 degrees with respect to the coil 3 is obtained by the television camera 10, and further, the image processing device 14
To extract the image signal corresponding to the laser slit light,
Then, the projection angle θ of the laser light is
Then, the height of the point where the laser light hits is calculated from the above and the position of the laser light based on the above-described calculation formula. By sequentially performing this operation for a plurality of lines, it is possible to obtain a plurality of cross-sectional shapes of an object in a measurement visual field such as a coil / cart and a floor surface.

Next, the coil operation device 18 uses the shape data to identify the coil and the peripheral part (the floor and the truck) from the difference in height because the coil is higher than the floor and the truck. To extract only the shape of the coil. Furthermore, in order to detect the position of the coil from the plurality of cross-sectional shapes of the extracted coil, the cross-sectional shape in the radial direction and the width direction of the coil is obtained.

FIG. 4 is an explanatory diagram for determining the cross-sectional shape of the coil in the radial and width directions. Here, the direction in which the shape data of the coil 3 is rotated by the installation angle (45 °) of the television camera 10 as the detection head, that is, the trolley 30
The shape data is projected in the traversing direction and the traveling direction, respectively. As a projection method, an average value of shape data in the coil width direction is obtained in the coil width direction. In the illustrated example, for example, an average value of the slit lights 41, 42, 43 at, for example, the illustrated points is obtained, and the average value is set as a value of a point in the projected shape in the coil width direction.
The projection value (shape data) 45 in the coil width direction is obtained by calculating the average value of the other points of 4, 43 and 44. Further, by taking the maximum value of the shape data in the coil radial direction in the coil radial direction, accurate shape data can be obtained. In the illustrated example, the slit lights 41, 42, 43, 4
4 are projected in the coil radial direction.
By taking the maximum value of 43a and 44a, a projected shape (shape data) 46 in the coil radial direction is obtained.

Although the above description is an example in the case where the arrangement direction of the coil 3 is known in advance, the same processing can be performed even when the direction is not known in advance. In such a case, the direction is temporarily determined, and then the projected shape (shape data) in the coil width direction and the radial direction is obtained, and the arrangement direction can be determined from the shape data. If the direction is incorrect, the projection shape (shape data) in the coil radial direction is obtained for the determined arrangement direction.

Next, a method of calculating the coil width direction position, the coil width, the coil radial direction center position, and the coil diameter from the shape data projected in the coil width direction and the radial direction will be described. As for the coil width direction, as shown in FIG. 5, by detecting points at the left and right ends that exceed separately set height data from the projected width direction shape data, the points are shifted to the right and left of the coil. Recognize as an edge. Therefore, the center position and the width in the coil width direction can be obtained by the following equations. Coil center position = (right edge + left edge) / 2 (5) Coil width = | right edge−left edge | (6) In the coil radial direction, the projected coil shape should be semicircular. Therefore, the center position and the diameter of the coil can be obtained by substituting the shape data into the equation of the circle. (X−c _x ) ² + (z−c _z ) ² = r ² (7) x, z: semicircular shape data of the coil obtained by projection c _x , c _z : center position in the coil radial direction r: coil radius

Specifically, if there are data at three or more points in the radial direction of the coil, the above equation (7) can be solved. However, the measurement data in the radial direction of the coil can be effectively used to improve the reliability of the measurement. In order to improve the accuracy and accuracy of the measurement data in the coil radial direction, a plurality of combinations of three points are set, noise is removed from a plurality of center positions obtained by each calculation, and then statistical processing is performed. A highly reliable coil center position can be obtained.

As a method of removing noise, since noise takes an abnormal value (a value abnormally larger or smaller than the true value) with respect to the true value, a distribution of measured values is obtained and set in advance by majority rule theory. There is a method of removing points apart from the set range, and a method of deleting data of points set in advance in order of increasing distance from the average value of all the center positions obtained by the three-point calculation. Such a process is naturally used also at the stage of obtaining the cross-sectional shape in the coil radial direction and for removing abnormal shape data from the obtained cross-sectional shape.

The method of finding the true center position from the center positions of many coils includes the method of finding the average value of many points, and the method of dividing the distribution of many points into a mesh and determining the position where the maximum value of the distribution is obtained. There is a method to ask.

As described above, it is possible to easily remove an abnormal point (noise) by using a plurality of slit light data by the multi-slit light, and to realize a measurement which is not easily affected by the noise by the statistical processing. .

In this embodiment, as described above, the center position and width in the width direction of the coil,
Since the radial center position and diameter are determined, even if there is a situation where some laser slit light cannot be detected due to differences in the reflectance of a part of the coil, etc., the cross-sectional shape of the other parts that can be detected Since the shape of the part missing from can be obtained, measurement robust to disturbance can be realized. Further, in the present embodiment, the laser slit light is obliquely scanned with respect to the coil, a plurality of cross-sectional shapes are obtained, and these are projected in the radial direction and the width direction of the coil. The radial and radial center position of the coil is determined, and if it is known whether the direction of the coil to be measured is in the traverse direction or the traveling direction of the crane, the radial direction and the width direction can be determined. Even if they are interchanged, an operation such as changing the direction of the detection head is not required, and the coil position can be detected by one television camera and one slit light scanning device (laser light source). Further, in the present embodiment, the detection head can be constituted by one television camera and one slit light scanning device (laser light source), so that a compact detection head can be constructed, and Installation adjustments have also become easier.

[0029]

As apparent from the above description, the following effects are obtained according to the present invention. (1) A plurality of parallel slit lights are scanned on the upper surface of the coil by the light projecting means, and the upper surface of the coil is imaged by the imaging means, and position data of the coil is obtained based on the image signal. Since position data and the like can be obtained by statistical processing of data using light, highly reliable measurement is possible. (2) The slit light is scanned on the upper surface of the coil obliquely to both directions of the coil width and the diameter by the light projecting means. Therefore, the direction of the coil to be measured is the diameter relative to the traverse direction of the crane. Even if the direction and width direction are swapped,
An operation such as changing the direction of the detection head is not required, and one image pickup unit and one light projecting unit can cope with the operation. Further, since the detection head can be constituted by one image pickup means and one light projecting means, it is possible to construct a compact detection head. (3) The three-dimensional shape data of the plurality of slit lights are projected in the width direction of the coil to determine the radial center position of the coil and the coil diameter, and the three-dimensional shape data of the plurality of slit lights are parallel to the reference plane. Since the center position in the width direction of the coil and the coil width are calculated by projecting in the radial direction of the coil, in the automatic operation of the overhead crane, the stop position of the coil bogie such as the trailer is slightly shifted or the bogie is loaded on the bogie. Even if the position of the coil is deviated from a predetermined position, the position of the coil can be accurately detected, and the automatic operation of the overhead crane which has been conventionally performed by a dedicated operator can be realized. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram for explaining a measurement principle of a coil position detecting device of the present invention.

FIG. 2 is a diagram illustrating a configuration of a slit light scanning device in FIG. 1;

3A and 3B are explanatory diagrams when the optical system of FIG. 1 is arranged on an overhead crane, wherein FIG. 3A is a plan view, FIG. 3B is a front view, and FIG. 3C is an image of a field of view of a television camera. FIG.

FIG. 4 is an explanatory diagram for determining a cross-sectional shape in a radial direction and a width direction of a coil.

FIG. 5 is an explanatory diagram for obtaining a coil width and the like from shape data in a width direction projected in a radial direction of the coil.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Hirokawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yasutoshi Fujikawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan (72) Inventor Kiyoshi Muta 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yasuhiro Akagi 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. ( 56) References JP-A-5-107028 (JP, A) JP-A-7-63519 (JP, A) JP-A-7-334680 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G01B 11/00-11/30 102 B66C 13/00-15/06

Claims (1)

(57) [Claims] 1. A light projecting means mounted on an overhead crane for transporting a coil and irradiating the coil upper surface while scanning a plurality of parallel slit lights in an oblique direction with respect to both directions of a coil width and a diameter. An imaging unit mounted on an overhead crane for imaging an upper surface of the coil irradiated with the slit light; and an image processing unit for performing image processing on an imaging signal of the imaging unit and extracting an image signal corresponding to the slit light from the image signal. Means, based on an image signal corresponding to the extracted slit light, shape calculating means for obtaining three-dimensional shape data of the slit light irradiating section for each of the plurality of slit lights, and The three-dimensional shape data of the slit illuminator is projected in the width direction of the coil to determine the radial center position of the coil and the coil diameter. And a coil calculating means for projecting the three-dimensional shape data of the slit illuminating portion for the light in the radial direction of the coil parallel to the reference plane to obtain a center position in the width direction of the coil and a coil width. Position detection device.