JP2634311B2 - Coil position detection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coil position detecting device applied to automatic (unmanned) operation of an overhead crane in a coil warehouse of a steel mill.

[Conventional technology]

The coil formed by winding a thin steel plate into a roll is stored in a warehouse during each iron-making process and waiting time at the time of shipping.

Recently, automatic (unmanned) operation of overhead cranes has been promoted in this coil warehouse for automation of work, which made it easier to manage work that was difficult in the past, improved productivity and homogenized. We plan to have a great effect of freeing people from working in bad environments, dangerous work and simple work.

In this case, what is problematic in automation of the overhead crane is the coil handling operation conventionally performed by a driver on a crane machine.

In other words, if the exact location of the target coil and the relative positional relationship between the coil position and the crane in the location are not clarified during the pandling operation, mishandling or load swing may occur, resulting in an accident. Is also a problem. Further, in the case of using a trailer as a method for entering Kyle into the warehouse, there is a problem that the control position of the coil position is deteriorated because the stop position of the trailer fluctuates.

Under the circumstances described above, a sensor that accurately gives the position of a predetermined coil to a crane is required, and as such a coil position detecting device, Japanese Patent Application No. 01-301829 has been proposed.

This device uses the cylindrical shape of the coil. By devising the arrangement of the two TV cameras and the light source, the height distribution in the radial and width directions of the coil is measured by triangulation. , The center position, radius and width of the coil.

First, after the overhead crane is roughly positioned at a preset trailer stop position, the present apparatus detects the coil position and performs accurate positioning.

The principle of detecting the center position, radius and width of the coil of the present apparatus will be described below with reference to FIGS.

FIG. 3 is a layout diagram of height detection by a triangulation method. Coil height distribution can be applied to overhead crane trolley 5
TV cameras 1 and 2 and a laser light source (including a scanning mirror) 3 are mounted, and measurement is performed based on the principle of triangulation.

FIG. 4 shows a principle diagram (radial direction) of height detection by the triangulation method. As shown in the figure, the point (x, y, z) on the coil to which the laser light is applied is given by the following equation, where the position of the laser light on the screen of the TV camera is (i, j).

Where h _o : distance between the TV camera and the ground C: distance between the TV camera and the laser light source (scanning mirror) θ: mounting angle of the TV camera h: detection distance α: incident angle of laser light to h β: TV The viewing angle of the camera in the vertical (J) direction r: the viewing angle of the TV camera in the horizontal (I) direction g: the resolution (dot number) of the shooting surface of the TV camera.

Therefore, by scanning the scanning mirror and irradiating the coil with laser (slit) light parallel to the Z-axis direction,
From the above equation, the radial height distribution of the coil is obtained.

Specifically, the coil is photographed by a TV camera with the laser light source turned off (turned off) and stored in the reference image memory. Next, the laser light source is turned on, the scanning mirror is scanned, and the coil is photographed by the TV camera. By calculating the difference between the photographed image data and the image data in the reference image memory, only the laser spot image can be extracted. By repeating this and integrating, laser spot images are connected and a laser slit image can be synthesized. Therefore, if each point on the laser slit image is processed by the above equation, a radial height distribution of the coil can be obtained. Similarly, the TV camera 2 is set on the z-axis, the scanning mirror is scanned, and x
By irradiating the coil with laser (slit) light parallel to the axial direction, a height distribution in the width direction of the coil can be obtained.

FIG. 5 shows a principle of detecting the coil position. here,
For convenience of explanation, the ground immediately below the laser light source (scanning mirror) on the trolley is defined as the origin 0, the x-axis is parallel to the trajectory of the overhead crane, the y-axis is parallel to the height direction, and the z-axis is parallel to the running trajectory. Set the xyz coordinate system that defines. As shown in FIG. 5, the coils are arranged so that the central axis (width direction) is parallel to the x-axis and the radial direction is parallel to the z-axis.

FIG. 5 (a) shows the projection position of the laser beam on the xy plane. FIGS. 5 (b) and 5 (c) show examples of the results of measuring the height distribution on the coil parallel to the x-axis and the z-axis.

From FIG. 5 (c), the width D of the coil and the center position B of the width are shown.
Is given by the following equation.

The height data in the radial direction in FIG. 5B satisfies the following circle equation with data on a coil (cylinder).

^{_{(Y i -y a) 2 +}} (z i -z a) 2 = r 2 (8) wherein, y _i and z _i is the height data of the radial direction on the coil (yen), y _a and z _a is the center coordinate of the circle, and r is the radius of the coil. Accordingly, the center position _A (y _a, z _a) of the circle and the radius r define (8) f = from the equation ^{_{(y i -y a) 2 +}} (z i -z a) 2 = r 2 (9) Then, y _a , z that minimizes the evaluation function F shown in the following equation
_a, be determined to r, y _a which they seek, z _a, a r.

Expression (10) is the position coordinates (y _i , z _i ) on the circumference of three or more points.
, It can be solved by Newton-Raphson method, for example.

From the above, the center position G (x _g , y _g , z _g ) of the coil and the radius r
And the width D are given by the following equation.

Therefore, if the hunt ring center of the crane is associated with the origin 0 of the coordinate system, the above values can be used as crane control amounts.

 FIG. 6 shows a configuration diagram of the conventional device.

[Problems to be solved by the invention]

 The above-mentioned prior art has the following problems.

In order to measure the height distribution in the radial and width directions on the coil, two scanning mirrors are controlled to move the laser beam parallel to the radial and width directions on the coil, which is shown in FIG. As shown in the figure, the image was taken with a TV camera, integrated by a binarizing device, binarized, and a laser slit image was synthesized.
Has been extracted.

In the above description, assuming that the luminance (signal) of the laser image on the image data of one frame before the integration processing is a and the luminance (noise) of the background is b, (a> b) S / NP is And the S / NQ of the image data after the n-frame integration process is Given by Here, n is the number of frames corresponding to the time required for the laser image to pass once from the left end to the right end on the image data.

Then, comparing the S / N of the image data before and after the integration process, , And the S / N of the image data
It can be seen that is decreased. Further, from the equation (2), it is also understood that the S / N decreases as n increases.

Therefore, the binarization device of the conventional coil position detection device is
Since the integration processing reduces the S / N of the image data, there is a problem in accurately extracting a laser slit image.

[Means for solving the problem]

A laser light source and a spot light of the laser light source;
Two scanning mirrors for converting into two-dimensional slit light and two TV cameras for photographing the slit light irradiated on the coil are installed on a crane in a coil yard. An A / D converter for digitizing the video signal of the TV camera, a binarizing device for extracting a laser slit image from the digitized image data, and a real space position data of the laser slit image on the image data. A coordinate conversion device for converting the three-dimensional position coordinates of the coil, a calculating device for solving the circular equation by the Newton-Raphson method for the three-dimensional position coordinate data in the radial direction of the coil, and calculating a center position and a radius of the coil, and a coil. And an end point detecting device for detecting the positions of both ends of the laser slit image on the coil with respect to the three-dimensional position coordinate data in the width direction and calculating the width of the coil. Before starting the measurement, turn off the laser light source and store the image data captured by the TV camera in the reference image memory, turn on the laser light source, scan the scanning mirror, and capture the image data and the reference image captured by the TV camera. After calculating the difference with the memory, the binarized image data is subjected to a logical OR operation and superimposed to synthesize a one-dimensional laser slit image (image data).

[Action]

 The operation of the present invention will be described with reference to FIG.

As can be seen by comparing FIG. 6 which is a configuration diagram of the conventional binarization device and FIG. 2 which is a configuration diagram of the binarization device of the present invention, the binarization device of the present invention is compared with the conventional device. Then, the order of the integration process and the binarization process is switched.

Thereby, a procedure is performed in which the difference between the image data captured by the TV camera and the image data in the reference image memory is calculated and then binarized to extract a laser image, which is integrated for n frames to synthesize a laser slit image. Become.

From the above, the S / N of the image data before binarization processing is
This is consistent with the equation (1), and is higher than the S / N of the conventional device (equation (2)). (Equation (3)) Accordingly, since the S / N of the image data subjected to the binarization processing is higher than that of the conventional apparatus, it is expected that the reliability of the laser slit image extraction accuracy is improved.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. 1, FIG. 2 and FIG.

In detecting the coil position, an arbitrary position on the ground in the coil yard is set as the origin 0, the direction parallel to the traverse direction is the x axis, the direction parallel to the running direction is the z axis, and the direction parallel to the winding direction is the y axis. Xyz rectangular coordinate system to be set.

1 and 2, reference numerals 1 and 2 denote TV cameras, 3 denotes a laser light source, and 6 denotes a scanning mirror. The laser light is reciprocated in parallel with the x-axis or the z-axis by the two scanning mirrors 6 and the laser light source 3. Selection of the x-axis and the z-axis is performed by 13 controllers. For convenience of explanation, TV
The camera 1 captures an image for measuring the height distribution of the coil 4 in the radial direction, and the TV camera 2 captures an image for measuring the height distribution of the coil 4 in the width direction. 7 is
An A / D converter for A / D converting a video signal of a TV camera, 8
Reference numeral denotes a reference image memory for storing a video signal of the coil 4 photographed without irradiating a laser beam. Reference numeral 9 denotes a binarizing device having the configuration shown in FIG. 10 is a coordinate conversion device for calculating the position (x, y, z) of the xyz coordinate system in the real space from the position (i, j) of one point on the image data, and 11 is a tertiary of three or more points in the radial direction of the coil. An arithmetic unit that solves the equation of a circle by the Newton-Raphson method from the original position coordinate data and calculates the radial center position and radius of the coil. 12 is the position of both ends of the coil from the laser slit image in the coil width direction. Is an end point detection device for detecting the end point. Reference numeral 13 denotes a controller which controls the operations of the TV camera laser light source and the scanning mirror, and calculates the calculation results (the center of gravity G of the coil G
(X _g , y _g , z _g ), width D and radius r), and has a function of outputting a control signal for controlling the operation of the crane.

The laser light source 3, the two scanning mirrors 6, and the TV cameras 1 and 2 are set on a trolley 5 on the ceiling or a traversing device that can traverse independently of the crane. FIG. 3 shows a schematic view of the set.

Now, the operation of the present device will be described assuming that the trolley 5 is roughly positioned above the coil to be handled which is set in advance.

First, the coils in the radial direction and the width direction are photographed by the TV cameras 1 and 2 in a state where the laser light is not irradiated.
After the A / D conversion by the converter 7, it is recorded in the reference image memory 8.

Next, the two scanning mirrors 6 are controlled to irradiate the laser beam on the coil so as to reciprocate in parallel with the radial direction of the coil. This is photographed by TV camera 1, and the video signal is
After the A / D conversion by the -D converter 7, in the binarization device 9,
After calculating the difference from the reference image memory 8, binarization is performed using a fixed threshold value, and integration for n frames (actually, a logical sum is calculated) allows synthesis and extraction of a radial laser slit image (No. (Figure 3, image data). This is a coordinate transformation device 10
After conversion into position data in the xyz coordinate system, the arithmetic unit 11 substitutes the data on the coil for the equation of the circle, and sends the radial center position ( _yo , _zo ) and radius r of the coil 4 to the controller 13. send. After receiving the data, the controller 13 controls the two scanning mirrors 6 to irradiate the laser beam onto the coil 4 so as to reciprocate in parallel with the width direction of the coil. this
The video signal is photographed by the TV camera 2, the video signal is A / D converted by the A / D converter 7, the difference from the reference image memory 8 is calculated in the binarization device 9, and then binarized by a fixed threshold , This is n
By performing frame integration (actually calculating a logical sum), a laser slit image in the width direction can be synthesized and extracted (FIG. 3, image data). The end point detector 12 detects the positions of both ends on the coil, and the coordinate converter 10 converts the data into position data in the xyz coordinate system, and calculates the width D of the coil 4 and the center position _xo of the coil 4 in the width direction. And sends it to the controller 13. After receiving the information, the controller 13 outputs a crane control signal.

〔The invention's effect〕

The present invention provides a laser light source, two scanning mirrors for converting spot light of the laser light source into one-dimensional slit light, and two TVs for photographing the slit light irradiated on the coil.
A camera is installed on a crane in a coil yard, an A / D converter for digitizing the video signal of the TV camera, a binarizing device for extracting a laser slit image from the digitized image, and A coordinate conversion device for converting the position data of the laser slit image into three-dimensional position coordinates in a real space; an arithmetic device for calculating the center position and radius of the coil with respect to the three-dimensional position coordinate data in the radial direction of the coil; In the coil position providing device, which detects the position of both ends of the laser slit image on the coil with respect to the three-dimensional position coordinate data in the width direction of the coil and calculates the width of the coil, Turn off the laser light source in advance and store the image data taken by the TV camera in the reference image memory, turn on the laser light source, scan the scanning mirror, and scan the TV camera. After calculating a difference between the image data and the reference image memory taken by La, the logic of the image data binarized
By providing a binarizing device for synthesizing a one-dimensional laser slit image (image data) by performing an OR operation and superimposing, the following effects are obtained.

(1) Since the S / N of the image data to be subjected to the binarization process is improved, the reliability of the process for synthesizing and extracting the laser slit image is improved.

(2) By performing the binarization before the integration processing, the memory required for the integration processing can be significantly reduced, which can contribute to a higher processing speed and a lower cost.

For example, assuming that the size of image data is 512 × 512 × 8 bits, the conventional apparatus requires 512 bits to perform the integration process.
X 512 x 16 bits (up to 256 times of integration), the memory of the present invention requires 512 x 512 x 16 bits.
One bit (the number of integrations (actually, the number of logical sum operations) is infinite) is obtained, and the memory capacity required for the integration processing is 1/16.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a coil position detecting device of the present invention,
FIG. 2 is a diagram showing the configuration of the binarizing device, FIG. 3 is a diagram showing the relative relationship between a TV camera, a laser light source and a scanning mirror, and FIG. 4 is a diagram for explaining the principle of coil position calculation. FIG. 3B is a front view, FIG. 3B is a side view, and FIG. FIG. 5 is a schematic diagram of the acquired data, in which (a) shows the projection position of the laser beam on the xz plane, (b) shows the height distribution in the radial direction, and (c) shows the height distribution in the width direction. FIG. 6 is a configuration diagram of a conventional binarization device. 1,2 TV camera, 3 Laser light source, 6 Scanning mirror, 7 A / D converter, 8 Reference image memory, 9 Binarization device, 10 Coordinate conversion device , 11 ... Calculator, 13 ... Controller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Okai 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Inside the Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Goo Murata 4-chome Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture No. 6-22 Mitsubishi Heavy Industries, Ltd. Hiroshima Laboratory (72) Inventor Koji Horimoto 4-6-22 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Works (56) References JP-A-59-230994 JP, A) JP-A-2-157603 (JP, A) JP-A-3-162395 (JP, A) JP-A-2-20105 (JP, U)

Claims (1)

(57) [Claims] 1. A laser light source, two scanning mirrors for converting spot light of the laser light source into one-dimensional slit light, and two TVs for photographing slit light applied to a coil.
An A / D converter for digitizing the video signal of the TV camera, a binarizing device for extracting a laser slit image from the digitized image data, A coordinate conversion device that converts the position data of the laser slit image into three-dimensional position coordinates in real space, and a calculation device that calculates the center position and radius of the coil with respect to the three-dimensional position coordinate data in the radial direction of the coil,
Before starting measurement in a coil position detecting device including an end point detecting device that detects the positions of both ends of the laser slit image on the coil with respect to the three-dimensional position coordinate data in the coil width direction and calculates the coil width The laser light source is turned off in advance and the image data captured by the TV camera is stored in the reference image memory, the laser light source is turned on, the scanning mirror is scanned, and the image data captured by the TV camera is compared with the reference image memory. A coil comprising a binarizing device for synthesizing a one-dimensional laser slit image (image data) by performing a logical OR operation and superimposing the binarized image data after calculating the difference. Position detection device.