JPS61167804A - Visual sensor - Google Patents

Abstract

PURPOSE:To identificate a groove easily and securely by converting an image of an object work into a binarization signal and approximating a line element calculated by outer periphery tracking by using three orthogonal straight lines. CONSTITUTION:The image of the object work 3 is read by a camera 4 at constant intervals and converted into a video signal, which is transmitted to an image input circuit 9. The circuit 9 converts the video signal into binary data, which is transmitted to an image storage circuit 11 after isolated-point removal. Then, the original image, binarization image, etc., are displayed on a monitor television 5. An operator, therefore, sets the kind of the local feature of the work 3, etc., on the screen of the television 5 with a light pen 6 and also indicates an aimed point in the binary image. The indication is made with the light pen 6 to supply a command to the circuit 9 from a central processor 7, and the circuit 9 convert the video signal of the work 3 which is read by the camera 4 into a binarization signal and also removes isolated points to send the resulting signal to an image processing circuit 10, which generates run-length data. The processor 7 tracks the outer periphery of the calculated area to generate a line element table.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a visual sensor for identifying the shape of a workpiece, measuring dimensions, etc. during assembly, transportation work, etc.

[Conventional technology]

Recently, equipment with advanced functions such as robots and automatic assembly machines have been introduced for production automation, but due to the lack of information on the shape and position of the target workpiece, it is difficult to respond to changes There are still many areas, such as manufacturing processes, that still have to rely on human labor. Therefore, visual sensors will be essential in order to further automate these processes in the future. The visual sensor is a sensor that measures characteristic data such as the area, outer circumference, hole area, maximum length from the 1-type center, and minimum length of multiple workpieces that are separated on the monitor screen, and uses that data for teaching. It is necessary to have a function to automatically identify which of the taught works corresponds to the work, and to identify specified shapes such as circles, ellipses, and rectangles from the window part of the screen. has been progressing.

[Problem that the invention seeks to solve]

In addition to the above-mentioned recognition functions, the visual sensor also needs to identify grooves as shapes in the target workpiece, and as no effective method has been found for this purpose, there are problems such as restrictions on automation of assembly.

The present invention has been made in order to solve the above problems, and provides a visual sensor that can easily and reliably identify grooves in the figure of a target workpiece by approximating them with three straight lines orthogonal to each other. It is an object.

[Means for Solving the Problems] The visual sensor according to the present invention binarizes the image of the target workpiece and converts ls″g obtained by outer circumferential tracking into three orthogonal values.
The groove is recognized as a figure by approximating it with a straight line.

[For production]

In this invention, a groove is approximated by three straight lines that are orthogonal to each other among the line elements obtained from the target figure, and the shape of the groove is recognized using the same concept as for empty figures such as circles, ellipses, and rectangles.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

First, in FIG. 1, 1 is a visual sensor control device, 2 is a visual sensor control device;
Reference numeral denotes a host controller which gives a measurement command to the visual center control device 1, 3 a target workpiece to be measured, and 4 a camera which reads an image of the target workpiece 3 and converts it into a video signal. 5 is a monitor TV that displays the original image, binarized image, recognition results, and guidance for various operations. 6
is a manual in the teaching mode that registers the internal settings of the hardware and the target work to be recognized using Lightpe/.
1 machine interface. A central processing unit 7 decodes and executes instructions within the visual sensor control device 1. 8 is a storage circuit for storing programs and teaching data to be executed by the central processing unit T; 9 is a storage circuit that converts the video signal input from the camera 4 into a binary image, and further performs preprocessing such as removing isolated points; image input circuit,
10 is an image processing circuit that generates run length data based on the signal output from the image input circuit 9; 11 is an image storage circuit that stores the binary image from the image input circuit 9; and 12 is an image storage circuit that stores the recognition result; 13 is a monitor interface circuit with the monitor TV 5, and a light pen interface circuit with the 13-high 5 light pen 6.

14 is a higher-level interface circuit with the higher-level controller 2;

Next, the operation of this invention will be explained. First, the operation mode of the visual sensor control device 1 is a teaching mode in which the internal settings of the visual sensor control device 1 and the target work to be recognized are registered, and a teaching mode in which measurements are performed according to commands from the host controller 2 and measurement results are sent to the host controller 2. The online mode for reporting can be selected from the screen of the monitor television 5 by instructing with the LitePe/6.

In the teaching mode, the camera 4 reads an image of the target workpiece 3 at regular intervals, converts it into a signal, and transmits it to the image input circuit 9. In the image input circuit 9, as shown in FIG.
), the cipideo signal is binarized at the set binarization level, isolated points such as noise are removed, and the binarized data is transmitted to the image storage circuit 11. Here P
indicates the target point of the groove, WL indicates the range of the set window, and D indicates the binary image of the target workpiece. Then, the original image, the binarized image, etc. are displayed on the monitor television 5 according to the image selection. While looking at the screen of the monitor TV 5, the operator inputs the work number of the target work 3, the binarization level, the type of local feature such as circle, ellipse, rectangle, etc., and the window settings from the screen of the monitor TV 5 using the light pen 6. Let's do it. Further, the point of interest is indicated (by means of a binary image displayed on the screen of the monitor television 5). In the case of a groove, as shown in FIG. 2 (-), by pointing inside the groove with the point of interest P as the bottom surface, and then using the light pen 6 to indicate the start of measurement.
A command is given from the central processing unit 7 to the image input circuit 9. The image input circuit 9 binarizes the video signal of the target workpiece 3 read by the camera 4 at a set binarization level, removes isolated points, and generates run length data sent to the image processing circuit 10. The central processing unit 1 determines a region where thin lengths are continuously connected from the run length data, tracks the outer periphery of the determined region, and creates a line element table (FIG. 2(b)). For example, the left side of the area is determined as follows. The position of the starting point of the corresponding area or the left end of the cutting point (corresponding to the starting point as a run length) is (x(0),
y(0)], and then the position of the left end point of the nth run length is [x(n), y(n)],
A straight line passing through those two points is expressed by equation (1).

Here, the I position corresponding to y(1) to y(n-1) is xc
The end point of the run length (X(1)) when (1) to Xe (low 1).

y(1)] ~ (x(n-1), y(n-1)) in the X direction is lX, (i)-X(1)l≦ΔX ・
・・・・・・・・・・・・・・・・・・(2) 1=1 ~
n-1 lX: Allowed value 9 (If formula 21 is satisfied, repeat the same for the next run length).

1xc (amount) - X (amount) l>lX ・・・・・・・・・
・・・・・・・・・(3) Supervision = 1 to n-1 And if it becomes the formula (3), (x(n), y(n) )
Set Cx(0), y(0) ] to Cx(n
-1) sy(n-1) ] are registered in the line element table as the starting and ending points of one line element along with the slope (FIG. 3).

As shown in FIG. 4, the line element table is composed of data on the starting point position, ending point position, and slope for one line element.

Next, the line element closest to the designated groove point 4 on the screen of the monitor television 5 is found from the line element table. In FIG. 2(b), line element Li corresponds to this. Line element L
Find the line elements that make up the groove using i as a reference. Figure 2 (b
), the line element Li-1* Li+1 is positioned as the line element corresponding to the side surface of the groove, Li is the bottom of the groove Vcs Ll-2# Li+2 is positioned as the line element corresponding to the surface of the bay, and is recognized as a time groove that satisfies the following conditions. (Rectangular approximation of Fig. 2 (-)).

In the flowchart of Fig. 6, m line element Li- is considered as the bottom of the groove, and line elements Li-1 and L'
The angle θi-1, i+1 formed by t+t is 180°-β0≦θi-1, i+1≦180@+β6
...(4).

(2) li*L1 (!: Iq-1-Li+t
Let the angle θi-1. i #θ1−+1.

(3) The angle formed by the line elements Li-2 and Li*Li+2 and Ll is θi-2. When i +θi, i+2, ra
j≦θt-2, and θi, i+2≦r'・
−・−・・・−(Must be 63.

(4) Line elements Li-2 and I, l-1 wins Li+2 and Li+1
The angle formed by θt-2. t-t-θ1-1-1, i
It's time to make it +2.

Here, α, β, and r are permissible values.

If the specified figure is recognized as a groove based on the above judgment result, the groove width W, depth (left and right) dl are used as teaching data that defines the groove.

d2 is determined by equation (8).

Then, the binarization level and window range are registered in correspondence with the work number.

Regarding the direction of the groove, the inclination of the line elements forming the side surfaces and bottom of the groove from the reference line is θl-1+θl.

When θi+1, the direction of the groove θt− is determined by equation (9).

7=(θ, -1 +180') + (θ1-90')
10θl + 1 0. , t9) As described above, the direction θ of the groove is defined, and it is shown by a straight line passing through the midpoint (X6sF) of the line element Ll that constitutes the bottom.

In addition, in the online mode, the visual sensor control device 1 sends a total i111 command (with work No. specified) from the host controller 2 to the host interface circuit 14.
When the data is received via the central processing unit 7, the central processing unit 7 sets the window range and binarization level from the teaching data, gives a command to the image input circuit 9, reads the image of the target work 3 from the camera 4, and performs image processing. After the run length is generated by the circuit 10, a line element table is created in the same manner as in the teach blowfish mode.

In the online mode, since the point of interest is not specified on the screen of the monitor television 5, the groove is identified in the following steps based on the teaching data from the first line element. In the flowchart of FIG. 7, +13 When the line length of the line element of interest is ktj, r 1jW r≦δ ・・・・・・・・・
・・・・・・・・・・・・・・・・・・Find the line element Lj that satisfies α.

(2) Considering line element Lj as the bottom of the groove, line elements Lj-1 and Lj+
The angle θj-1, J+1 formed by 1 is 180-β0≦θj-1*j+1≦180@+β0 ・
...Be συ.

(The angle between 31 line elements Lj and "j-1s Lj+1 is θ
j−4sj 'θj I j+1.

(4) When the angle between line element L3-2, Lj m''j+2 and Ig is θj-21J IθLJ+2, -γ0≦θj-2eJ and θLj+2≦r0 °-
°−°−°−(Must be 13.

(5) Line elements Lj-2 and Lj-1*Lj+2 and Lj+
1 is the angle θj −2* j−1e ' J +l
It is time to set e j +2.

(6) The angle of the line elements LJ-1, LJ, Lj+1 from the reference line is θj-1. When θj, θj+1, the depth d1' (additional.

d2' (right) becomes. These depths di' (a, d21 (right)
be satisfied.

Here, α and βIrlδ are permissible values.

Line element Lj-1* Lj that satisfies the above 11) to (6)
* If Lj+1 exists, calculate the groove direction θ using the same method as during teaching, and send the measurement data d1', d2', W and position (x,
! , yc) and direction θ (Fig. 5(a) #
(b) ) a [Effects of the Invention] As described above, according to the present invention, in order to treat the groove as a figure of the target work by approximating it with three straight lines orthogonal to each other, the central processing unit applies it to a certain calculation formula. Since recognition and determination are automatically performed, grooves in figures can be easily and reliably recognized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a visual sensor control device according to an embodiment of the present invention, and FIG. 2 shows a target workpiece (1
) binary image, (b) line element, (C) model diagram of rectangular approximation,
Figure 3 is a run length diagram of the area of the target workpiece, Figure 4 is a line element table diagram, Figure 5 is a diagram of measurement commands and measurement results from the host controller, Figure 6 is a flowchart of the recognition algorithm during teaching, and Figure 6 is a flowchart of the recognition algorithm during teaching. FIG. 7 is a flowchart of the recognition algorithm when online. 1 is a visual sensor control device, 2 is a host controller, 3
is a target work, 4 is a camera, 5 is a television monitor, 6 is a light pen, 7 is a central processing unit, 8 is a storage circuit, 9 is an image input circuit, 10 is an image processing circuit, 11 is an image storage circuit,
12 is a monitor interface circuit, 13 is a light pen interface circuit, and 14 is a host interface circuit.

Claims (2)

[Claims] (1) A host interface circuit that sends and receives measurement commands and measurement results for the target workpiece to and from the host controller, and a video signal from the camera that reads the image of the target workpiece.
an image input circuit that performs value conversion and removal of isolated points; an image processing circuit that generates a run length based on an output signal from the image input circuit; and an image that stores a binary image and a recognition result from the image input circuit. A memory circuit, an interface circuit for a monitor television and a light pen for displaying the recognition results and man-machine interface for teaching, etc., a memory circuit for storing recognition programs and teaching data, and a central processing unit for controlling these. A visual sensor with (2) As a groove recognition means in the central processing unit, a picture element table is created using three straight lines orthogonal to each other from the binarized image obtained by the image input circuit, and a predetermined calculation formula is created from the picture element table. 2. The visual sensor according to claim 1, wherein the direction, depth, width, position, and direction of the groove are determined using the following method, and the results of the calculation are reported to a host controller.