JPH10185515A - Coil position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a measurement even when the coil is mounted in an orientation deflected from the travel direction of a crane by finding the three-dimensional figure data based on picture signals corresponding to slit light by processing image pickup signals and finding central positions in width and diametral directions of a coil by projecting the figure data in the width and radial directions of the coil. SOLUTION: A slit-light scanner 12 is positioned on the x-axis of a TV camera 10 and adjusted so that the direction of slit laser beams emitted from the scanner 12 can become parallel with the y-axis of the camera 10. A coil 3 to be measured is positioned so that the axial direction of the coil 3 can be aligned with the travel direction of a crane. Picture signals are obtained by irradiating the coil with the slit laser beams in the radial direction in parallel with the axial direction of the coil and the picture signals corresponding to the slit laser beams are extracted by means of a picture processor 14. A shape computing arithmetic device 16 computes the heights of points hit by the laser beams from the projecting angles θ and positions of the laser beams based on a prescribed operational expression and finds a plurality of cross-sectional shapes of an object, such as the coil, a truck, a floor surface, etc., in the visual field for measurement.

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 a 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.

(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-described 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 which enables measurement even if the coil position is shifted with respect to the direction.

[0007]

A coil position detecting apparatus according to the present invention is mounted on an overhead crane for transporting a coil, and scans a plurality of slit lights parallel to a coil width direction in a coil radial direction while scanning the coil in a coil radial direction. Light emitting means for irradiating the upper surface, imaging means mounted on an overhead crane for imaging the coil upper surface on which the slit light is scanned, and image processing of an image signal of the imaging means, and corresponding to the slit light from the image signal Image processing means for extracting the extracted image signal, and shape calculation means for obtaining three-dimensional shape data of the slit light irradiation unit for each of the plurality of slit lights based on the image signal corresponding to the extracted slit light, By projecting the three-dimensional shape data of the slit light irradiating unit for a plurality of slit lights in the width direction of the coil, and calculating the radial center position of the coil and the coil diameter In addition, there is provided a coil calculating means for projecting the three-dimensional shape data of the slit light irradiating section for a plurality of slit lights in the radial direction of the coil parallel to the reference plane to obtain the center position in the width direction of the coil and the coil width. .

In the present invention, the light projecting means mounted on the overhead crane irradiates a plurality of slit lights parallel to the coil width direction onto the coil upper surface while scanning in the coil radial direction. Then, the imaging means mounted on the overhead crane images the state. The image processing means performs image processing on the video signal of the imaging 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 irradiation unit for each of the plurality of slit lights. The coil calculating means projects the three-dimensional shape data of the slit light irradiating section for the plurality of slit lights in the width direction of the coil to determine the radial center position and the coil diameter of the coil, and also calculates the slits for the plurality of slit lights. The three-dimensional shape data of the light irradiation unit is projected in the radial direction of the coil parallel to the reference plane, and the center position in the width direction of the coil 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 to be in the y-axis direction in FIG. 1, and the second scanning mirror 24 whose rotation is controlled by the drive motor 24a projects the laser slit light in the x-axis direction in FIG. Control the position. 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 is given by the following equation. 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 so that its transverse direction is the raster direction of the television camera and its optical axis is 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 so that the coil width direction is the traveling direction of the crane 30. Note that the arrangement direction of the coil 3 is grasped by a system computer that manages the yard.

In this state, the slit light scanning device 12 irradiates the upper surface of the coil 3 with the laser slit light while scanning the laser slit light at substantially equal intervals in the coil radial direction in parallel with the coil width direction. Then, a slit light image is obtained by the television camera 10, an image signal corresponding to the laser slit light is extracted by the image processing device 14, and the projection angle θ of the laser light and the laser light From the position and the height, the height of the point irradiated with the laser beam is calculated 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. The cross-sectional shape is obtained by projecting the coil shape data in the coil radial direction and the width direction. As a projection method, an average value of shape data in the coil width direction is obtained in the coil width direction. 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.

Next, a method for obtaining the coil width direction position, coil width, coil radial direction center position and coil diameter from the shape data projected in the coil width direction and the radial direction will be described. Regarding the width direction of the coil, as shown in FIG.
By detecting points at both left and right ends exceeding height data set separately from the projected shape data in the width direction, the points are recognized as right and left edges of the coil. 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 |

An example of measurement in the coil radial direction of the coil will be described with reference to FIGS. FIG. 5 is a diagram showing a projected shape when the coil is placed parallel to the crane traverse direction, and FIG. 6 is a view showing a projected shape when the coil is placed slightly inclined with respect to the crane traverse direction. FIG. Note that in FIGS. 5 and 6, the height data has the z-axis on the near side of the paper.

In measuring the coil width, the positions of the left end face and the right end face of the coil are determined by the least square method or the like using the left edges L1 to Ln and the right edges R1 to Rn of the coil cross section data. The inclination φ of the coil and the width of the coil are obtained from the end face position data. The coil radial direction center position is based on the fact that the coil is circular in shape from the projected semicircular shape data by projecting shape data in the coil width direction onto a projection plane parallel to the axis of the tilt angle φ of the coil. Then, the coil center position and the coil diameter are 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, the above equation (7) can be solved if there are data at three or more points in the radial direction. However, in order to use the measured data in the radial direction effectively and improve the reliability of the measurement. In addition, three or more combinations of three points are set for the measurement data in the radial direction, noise is removed from a plurality of center positions obtained by each calculation, and the subsequent measurement processing is performed to improve accuracy and reliability. A high coil center position can be determined.

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 processing is naturally used also at the stage of determining 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 data of a large number of points (a plurality of slit light data), and to perform measurement which is hardly affected by noise by statistical processing. realizable.

In this embodiment, if the center position in the radial direction of the coil is determined based on the above equation (7), the center position in the coil width direction becomes the center position (y 'in the coil radial direction).
Axis) and at the center (on the x 'axis) of the left and right coil end face positions, so that the intersection (x', y ') with the center position (y' axis) in the coil radial direction is It can be easily calculated. Therefore, according to this embodiment, even if the direction of the coil is slightly inclined at the coil installation position, the shape of a plurality of cross sections is measured. Both can be measured, and the coil can be lifted accurately by rotating the lifter by the tilt angle φ of the coil.

In this embodiment, the center position and width in the width direction of the coil and the center position and diameter in the radial direction are obtained from a plurality of coil cross-sectional shapes. Even if the laser slit light cannot be detected, the shape of the missing part can be obtained from the cross-sectional shape of the other part that can be detected, so that measurement robust to disturbance can be realized.

Further, in this embodiment, since the detection head can be constituted by one television camera and one slit light scanning device (laser light source), a compact detection head can be constructed. The installation adjustment of the detection head can also be easily performed.

[0031]

As apparent from the above description, the following effects are obtained according to the present invention. (1) A plurality of parallel slit light beams are scanned on the upper surface of the coil by the light projecting means, the image is captured by the image capturing means, and position data of the coil is obtained based on the captured image signal. Even if it is arranged, it is possible to eliminate the influence, and since position data and the like can be obtained by statistical processing of a plurality of data by a plurality of slit lights, highly reliable measurement becomes possible. I have. (2) 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 and the coil diameter of the coil, and the three-dimensional shape data of the plurality of slit lights are converted into a coil parallel to the reference plane. The center of the coil in the width direction and the coil width are calculated by projecting in the radial direction of
In the automatic operation of the overhead crane, even if the stop position of the coil bogie such as a trailer is slightly shifted or the position of the coil loaded on the bogie is deviated from a predetermined position, the position of the coil can be accurately detected. This makes it possible to realize the automatic operation of the overhead crane, which was conventionally performed by a dedicated operator.

[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 of a coil in a width direction.

FIG. 5 is a diagram showing a projected shape when a coil is placed parallel to the crane traversing direction.

FIG. 6 is a diagram showing a projected shape when the coil is placed slightly inclined with respect to the crane traversing direction.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Hirokawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Yasutoshi Fujikawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun Inside the Kokan Co., Ltd. (72) Inventor Kiyoshi Muta 1-1-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Inside Nihon Kokan Co., Ltd. (72) Inventor Yasuhiro Akagi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside the corporation

Claims (1)

[Claims] 1. A light projecting means mounted on an overhead crane for transporting a coil and irradiating a plurality of slit lights parallel to a coil width direction onto an upper surface of the coil while scanning in a coil radial direction, and mounted on the overhead crane. Imaging means for imaging the upper surface of the coil irradiated with the slit light, image processing means for performing image processing on an imaging signal of the imaging means, and extracting an image signal corresponding to the slit light from the image signal; A shape calculating means for obtaining three-dimensional shape data of the slit light irradiating section for each of the plurality of slit lights based on an image signal corresponding to the extracted slit light; and a slit light irradiating section for the plurality of slit lights. 3
The three-dimensional shape data of the slit light irradiating part for the plurality of slit lights is obtained by projecting the three-dimensional shape data in the width direction of the coil to determine the radial center position and the coil diameter of the coil. A coil position detecting device comprising: a coil calculating means for projecting in a radial direction to obtain a center position of a coil in a width direction and a coil width.