JPH02100181A - Visual sensor - Google Patents

Abstract

PURPOSE:To dissolve such a problem where the identification of a work is impossible owing to the tilt of the work surface and the change of the light reflection factor, etc., by storing the allowance value of the feature data on a work into a memory and discriminating whether the value that identifies the work is kept within an allowance range or not in an operation mode. CONSTITUTION:In a teaching mode of a visual sensor, the allowance value of the feature data on a work 3 to be identified as the teaching data is previously registered in a memory circuit 8 via a register data device 6 together with the number and the binarization level of the work 3. Then it is decided whether the value that identifies the work 3 is kept within an allowance range set previously or not in an operation mode. If so, the work 3 can be identified. Then the identification data is outputted and displayed. If not, an error is displayed. Thus it is possible to eliminate such a problem where the identification of the work 3 is impossible due to the tilt of the work 3, the change of the light reflection factor, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a visual sensor for a target workpiece in, for example, factory automation assembly work or transportation work, etc., in particular, it is possible to set the permissible range of characteristic data of the target workpiece, The present invention relates to a visual sensor that can determine whether a value used to identify a workpiece is within a set tolerance range.

[Conventional technology] Currently, robots and various automation devices with advanced functions are being introduced to promote automation of production processes in factories, but the shape and position of the workpieces targeted by these automation devices are not determined. Because of this lack of technology, it is not possible to respond to these changes, and there are still some fields that have to rely on human labor, such as assembly processes, and visual sensors are indispensable in order to automate these processes.

Figure 6 is a configuration diagram of a conventional visual sensor, in which (IA) is a visual sensor control device, (2) is a host controller, (3) is a workpiece, (4) is a camera, and (5) is a monitor display. (6A) is a recording data device, (7) is a central processing unit, (8A) is a storage circuit that stores programs and teaching data to be executed by the central processing unit (7), and (9) is an image input circuit. , (1o) is an image input circuit (9
); (11) is an image storage circuit; (12)
(13) is a monitor interface circuit, and (13) is an upper interface circuit.

Conventional visual sensors are configured as described above.

Next, the operation shown in FIG. 6 will be explained.

First, in "teaching mode", the camera (4)
After reading the image of the target workpiece 3) at a constant period, it is converted into a video signal and supplied to the image input circuit (9). The image input circuit (9) binarizes the input video signal according to the set binarization level, removes isolated points, and supplies the output signal to the image storage circuit (10). (5) includes an image input circuit (
An original image outputted from 9) or a binary image processed by the image processing circuit (10) is selected and displayed via the monitor interface circuit (12). The operator sets the work number, binarization level, etc. to the target work (3) on the screen of the monitor display (5) using the registration data device (6A). Next, when an identification start command etc. is input from the registered data device (6A), the video signal of the target workpiece (3) read by the camera (4) is sent to the image processing circuit (10) to generate run length data.

From this run length data, the central processing unit (7)
Target work (3) such as area, outer circumference, large area, maximum length and minimum length from the center of gravity to the outer periphery of this work
Characteristic data representing the external shape of is calculated, and these calculated data are displayed on a monitor display (5) and stored in a storage circuit (8).

Next, in the "operation mode", when an identification start command, etc. is input from the upper controller (2), it identifies which of the works that have already been taught corresponds to it, and outputs the identification result to the upper controller (2). do.

[Problems to be Solved by the Invention] In the conventional visual sensor as described above, when identifying a target work, the permissible range of characteristic data of each work is fixed, and the range can be set to a desired range by the operator. Therefore, there were problems such as the inability to identify the work due to changes in the inclination of the work surface or the reflectance of light.

This invention has been made to solve the above-mentioned problems, and aims to provide a visual sensor that can set the permissible range of each data to a desired range in accordance with the characteristics of the target work. It is something.

[Means for Solving the Problems] A visual sensor according to the present invention includes: a camera that reads an image of a target work; an image processing circuit that generates a run length from the image of the target work read by the camera; an image storage circuit that stores a binary image obtained by converting the image of A registration data device that registers allowable values of characteristic data, etc., a storage circuit that stores teaching data registered from the registration data device, and a host controller are connected so as to receive identification commands and send out identification results. and a central processing unit that controls the entire visual operation in teaching mode and operation mode.

[Function] In the present invention, when the visual sensor is in the teaching mode, the number of the work to be identified as teaching data, the binarization level, and the allowable value of the feature data are registered in advance in the storage circuit using the registration data device. Keep it
In the operation mode, it is determined whether the value used to identify the work is within a preset tolerance range, and if it is within the tolerance range, identification is possible and identification data is output and displayed. If it is outside the allowable range, an error is displayed and the process ends.

[Example] Fig. 1 is a block diagram showing an example of the visual sensor of the present invention, and shows (2) to (5), (7), (9) to (13).
) is exactly the same as the conventional device described above. (1) is a visual sensor control device of the present invention, and (8) is a registration data device that includes an identification allowable range data input section therein.

(8) is a storage circuit that includes an identification permissible range data storage section therein.

FIG. 2 is a flowchart of the control operation of this invention,
FIG. 4(a) is a flowchart for the teaching mode, and FIG. 2(b) is a flowchart for the operation mode.

FIG. 3 is an explanatory diagram of the line element table.

FIG. 4 is a diagram explaining input/output data with the upper controller, where (a) shows the work number, which is an identification command from the upper controller, and (b) shows the output data to the upper controller. FIG. 6 is an explanatory diagram showing characteristic data of identification results.

FIG. 5 is an explanatory diagram illustrating the permissible range of identification according to the present invention.

The operation of FIG. 1 will now be explained with reference to FIGS. 2 to 5. First, in the "teaching mode", an image of the target workpiece (3) is read by the camera (4) at regular intervals, and then converted into a video signal and output to the image input circuit (9). The image input circuit (9) binarizes the video signal using a set binarization level, removes isolated points, and outputs the signal to the image storage circuit (11). Then, an original image, a binary image, or the like is selectively displayed on the monitor display (5) by an image selection operation. The operator, while looking at the screen of this monitor display (5),
) The settings of the work number and binarization level corresponding to the target work (3) in step 820 of the flowchart, and the settings of the identification tolerance range in step S21,
This is done by the registration data device (8).

The registration data device (6) has a built-in identification tolerance range data input section for this purpose. In addition, Fig. 5 is an explanatory diagram in which this identification tolerance range is set, and the minimum value constant (α% ) and maximum value constant (β%)
Set the value of . Next, step S22 in FIG. 2(a)
When the identification start command is manually issued from the registered data device (6), the central processing unit (7) detects the target work (read by the camera (4) and input to the image input circuit (9)).
3) video signal at the set binarization level.
The image processing circuit (l
O) to generate run length data. Next, the central processing unit (7) determines a region where run lengths are continuously connected from the run length data, tracks the outer periphery of this determined region, and creates a line element table as shown in Figure 3. create. The line element table shown in FIG. 3 contains the required number of data on the coordinates of the starting point, the coordinates of the ending point, and the slope of the line elements. Central processing unit (7
) calculates the area, outer circumference length, large area, and length from the center of gravity to the outer circumference corresponding to the workpiece (3) using the line element table. Next, in step 821 of FIG. 2(a), the minimum value constant (α%) and maximum value constant (β%) respectively set by the registered data device (6), the area, outer circumference length, and Multiply the large area and the length from the center of gravity to the outer circumference to calculate the allowable range determined by the upper and lower limits of each. For example, the tolerance range for area is as follows (
1) and (2).

Lower limit of area - Minimum value constant (α %) x calculated area ... (1) ■ Upper limit of area - maximum value constant (β %) x calculated area ... (2) These allowable ranges are the second In step S23 of FIG. 10A, the identification result data is displayed on the monitor display (5) and stored in the storage circuit (8).

Next, in the "operation mode", the
) The work number is set in step 830. The setting of this work number is performed by the upper controller (2) via the upper ink face circuit (13) to the central processing unit (7).
This is done by manually entering an identification number into the This identification number is shown as the workpiece number in FIG. 4(a). The central processing unit (7) outputs a workpiece identification start command in step S31 of FIG. 2(b), and by the same operation as above, as shown in FIG. 4(b), the area corresponding to the workpiece, Calculate the characteristic data of the outer circumference length, hole area, and length from the center of gravity to the outer circumference. In the next step 832,
It is determined whether each of the calculated feature data falls within the allowable range specified by the upper and lower limit values set in the "teaching mode". For example, the discriminant for area is the following equation (3) or (4).

Lower limit of area ≦ Area in operation mode ≦ Upper limit of area ... (3) Area in teaching mode × α1% ≦ Area in operation mode ≦ Area in teaching mode X β1% ... (4) Step If the determination result in S32 is within the allowable range, identification is possible, and in step S33, the identification result is displayed on the monitor display (5), and the fourth
Identification data shown in Figure (b) (work number, area, outer circumference length, hole area, and distance from center of gravity to outer circumference)
It also outputs the center of gravity data. If it is outside the allowable range, an error message is displayed on the monitor display (5) in step 834, and the process ends.

In the above embodiment, it is possible to set each tolerance value for the area, outer circumference length, hole area, and length from the center of gravity to the outer circumference, which indicate the characteristics of the workpiece, but the present invention is not limited thereto. Instead, for example, by measuring a circular or rectangular object and setting tolerance values for the radius and side length of the circle, the same effects as in the above embodiment can be achieved.

[Effects of the Invention] As described above, according to the present invention, in the teaching mode, tolerance values for each piece of workpiece characteristic data such as area, outer circumference length, hole area, length from center of gravity to outer circumference, etc. are registered data. It is set by the device and stored in the storage device, and in the operation mode it is determined whether the value used to identify the workpiece is within a preset tolerance range. Problems such as inability to identify due to changes in etc. are solved,
This has the effect of expanding the range of applications to which the visual sensor can be applied and expanding the applicable market.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the visual sensor of the present invention, FIG. 2 is a flowchart of the control operation of the present invention, and FIG.
The figure is an explanatory diagram of the line element table, Fig. 4 is an explanatory diagram of input/output data with the host controller, Fig. 5 is an explanatory diagram of setting the permissible range of identification of this invention, and Fig. 6 is an explanatory diagram of the conventional visual sensor. FIG. In the figure, (1) and (LA) are the visual sensor control device, (2) is the upper controller, (3) is the workpiece, and (
4) is the camera, (5) is the monitor display, (8), (
6A) is the registered data device, (7) is the central processing unit, (4
), (8A) is a memory circuit, (9) is an image input circuit,
(lO) is an image processing circuit, (11) is an image storage circuit, (
12) is a monitor interface circuit, and (13) is a higher-order interface circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts. Figure 2 (b) Agent: Patent Attorney Souji Sasaki D

Claims (1)

[Scope of Claims] A camera that reads an image of a target workpiece, an image processing circuit that generates a run length from the image of the target workpiece read by the camera, a binary image obtained by binarizing the image of the target workpiece, and An image storage circuit that stores the identification results, a display that displays the binary image or identification results, etc., and registration data that registers the number of the work to be identified as teaching data, the binarization level, the allowable value of the feature data, etc. The device, a storage circuit that stores teaching data registered from the registered data device, and a host controller are connected to receive identification commands and send out identification results, and to control the entire visual movement in teaching mode and operation mode. A visual sensor characterized by comprising a central processing unit that performs control.