JP2765181B2 - Visual device for moving work and work posture determination device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a visual device for obtaining a work image of a moving work and a work posture determination device.

[Conventional technology]

In an automatic assembly line, etc.,
If the work has a direction, the posture is determined during feeding, and a work in a bad posture is eliminated by a sorting mechanism.

[Problems to be Solved by the Invention] This work posture determination is conventionally performed by using mechanical means such as providing an attachment on a work feed path. In addition to those that cannot be distinguished, and when the shape of the workpiece changes,
Since the attachment had to be changed, changing the work was troublesome.

In recent years, image sensors and image processing technology for processing the image output have been developed, so a moving workpiece is imaged using a two-dimensional image sensor (especially a CCD camera), and the image output of this image sensor is processed. Although the method of determining the posture of the work has been proposed, the image input time of this type of image sensor is large, for example, 1/60 sec, and it takes time to process the image output. There is a problem that the work transfer interval is restricted, and the processing capacity of the drive assembly line or the like cannot be sufficiently increased. In addition, since the image processing apparatus gives a timing to take in image data, the work must be within the field of view of the image sensor. It was necessary to provide a separate position sensor to detect the entry.

The present invention has been made in view of the above-described problems, and can obtain a two-dimensional image of a moving workpiece without using the position sensor by using a line-type CCD image sensor having a high image input speed. Even in the case of a workpiece shape that is difficult to determine by using the mechanical means described above,
It is an object of the present invention to provide a visual device for a moving work and a work posture discriminating device which can be accurately performed in a short time and without being affected by the moving speed of the work.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a visual device for a moving work, comprising: a line-type image sensor for picking up a work transferred in a direction intersecting a line direction; and image data for one line sequentially transmitted by the image sensor. To detect the front end of the work by its first change, and to detect the rear end of the work by a change to the same image data as before the change, the object detection circuit detects the work The image data stored in the image memory is transmitted to an apparatus for transferring a workpiece among image data transmitted from an image sensor. The image data was taken out in synchronization with the pulse output of the attached encoder.

According to a third aspect of the present invention, there is provided a work posture determining apparatus for sequentially reading a sample image of a work and image data in the image memory, and determining a work posture from image data in a window taught by the teaching device. A determination circuit is provided, and the window is set to one non-overlapping region when a front-back image of the sample image is superimposed on the sample image.

According to a fourth aspect of the present invention, a memory switching circuit is provided with at least two image memories in the discriminating device. Is separated from the object detection circuit and connected to the discrimination circuit, and the other image memory is separated from the discrimination circuit and connected to the object detection circuit.

According to a fifth aspect of the present invention, there is provided a work posture determining apparatus for monitoring a line-type image sensor for picking up a work transferred in a direction intersecting with a line direction, and monitoring one line of image data sequentially transmitted by the image sensor. The object detection circuit detects the front end of the work by the change of the object, and detects the rear end of the work by the change to the same image data as before the change, and the image is detected while the object detection circuit detects the work. An image memory for teaching that sequentially stores data,
A teaching device for teaching a sample image of a work when the work is transferred in a predetermined posture, a template memory for storing image data of at least the first and second work characteristic portions taught by the teaching device, A matching memory for receiving the image data, a determination circuit for comparing the matching image data in the matching memory with the image data of the work characteristic portion to determine whether or not there is matching between the two; The image data of the second work characteristic portion is image data in a rectangular frame which is set on the image front end side and the image rear end side from the shape change point of the sample image and extends over the work image portion and the non-work image portion. The determination circuit determines a word based on the matching order between the two templates and the image data in the matching memory. In this configuration, the work posture is determined.

According to a sixth aspect of the present invention, the template memory stores at least the first work feature portion image data.
And a second line memory storing the image data of the second work feature portion.
The memory has a first line memory and a second line memory which perform a first-in first-out operation in a front-back relationship, and each time one pixel of data is read from the image sensor, the two line memories are first. Is sent to the judgment circuit, and the judgment circuit sends the data sequentially sent from the first line memory and the second line memory of the matching memory to the corresponding line of the template memory. -The operation of comparing with the data at address k in the memory is repeated.

[Action]

In the visual device of the present invention, the transferred work is imaged by the line-type image sensor, and the object detection circuit detects the leading end of the work by the first change of one line of image data sequentially transmitted by the image sensor. Then, the rear end of the work is detected by the change to the same image data as before the change, and the image data is sequentially stored in the image memory while the object detection circuit detects the work.

In the work posture determining apparatus according to the present invention, a window is taught to one non-overlapping area when a sample image is superimposed on a sample image by an inverted image of the sample image. A work attitude is determined based on whether the image data in the window of the work image among the image data of the work taken in by the determination circuit is equal to or greater than or equal to a threshold value.

Further, in the work posture determining apparatus of the present invention, in which the image data of the work characteristic portion is used as the determination data, the work image portion and the non-work image portion extend from the shape change point of the sample image to the image front end and image rear end, respectively. The image data (the image data of the first and second work feature portions) in the rectangular frame is stored in the template memory. The determination circuit performs matching between the matching image data for one line stored in the matching memory or the data of all pixels of the image sensor updated for each pixel, and the image data of the first and second work characteristic portions. Determine the presence or absence, the order of matching,
For example, if the matching is performed with the image data of the first work feature portion and then with the image data of the second work feature portion, it is determined that the work posture is the desired posture.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a transfer device (conveyor) for automatically transferring a work (an example is shown in FIG. 4) W from a work supply line A and feeding the work W to a sorting line B side. 12
Is a pulse encoder connected to the pulley 11 of the transfer device 10. This work W has a shape consisting of a base W1 and a base W2 which is reduced in diameter and protrudes from one end face of the base W1. The forward posture of W is assumed. Reference numeral 20 denotes an illumination light source that irradiates the workpiece W transferred to the transport device 10 from a horizontal direction perpendicular to the workpiece moving direction (arrow direction). Reference numeral 30 denotes a line-type image sensor (in this example, a line-type CCD camera), which is located at a position facing the light source 20 with the transfer device 10 interposed therebetween, and is transferred onto the transfer device 10;
The work W illuminated by the light source 20 is imaged, and its image data is sent out in the form of a signal I. This image data is input to an object detection circuit 42 through a synchronization circuit 41 of an image processing device 40 shown in FIG. Is done. As the CCD camera 30,
For example, effective pixels: 128 pixels, clock frequency: 1 MHz,
Image input time: 250 μsec. 43 and 45 are memory switching circuits, and 46 is an image memory. This image memory
46 consists of n-number of image memory (line memory) M ₁ ~M _n. 50 is a display device ((display)).

The direction of the pixel array (line direction) of the CCD camera 30
Are arranged in such a manner as to be directed to the moving workpiece W as shown by a broken line in FIG. 5, and as shown in FIG.
One line of image data is output at a constant period. CCD
Image data sent from the camera 30 is inputted to the synchronization circuit 41, the synchronization circuit 41 the image data for one line in synchronism with the rise and fall of _were pulse P that the encoder 12 is sent to the object detection circuit 42 Output. The object detection circuit 42 starts to transmit the input image data from the first timing when the image data is shifted from a state without “black pixels” to a state with “black pixels”, and “black pixels” are present. The transmission of the input image data is interrupted at the second timing when the state changes from the state where the “black pixel” has disappeared. The object detection circuit 42 detects the work W during these two timings, and during this work detection period (period T), every time one line of image data is received from the synchronization circuit 41, the memory W the switching signal S _W1 is sent to the memory switching circuit 43. The image data sent by the object detection circuit 42 is stored in a memory switching circuit 43
Are sequentially stored in the image memories M ₁ , M ₂ , M ₃ ,... Display device 50 gives the memory switching signal S _W2 to the memory switching circuit 45, Memojimemori _{M 1, M 2, M 3} , ··
························ Read image data stored in the.

Therefore, the image displayed on the screen is a two-dimensional image of the work W as shown in FIG.

In the present embodiment, since the line-type image sensor 30 is used, the image input speed is high, and since only the work image is captured, the time required for processing the image data is short. Restrictions on the work transfer speed and the work transfer interval can be relaxed.

When a two-dimensional image of the moving workpiece W is obtained by using the line-type image sensor as described above, the length of the two-dimensional image (X
The dimensions of direction) is affected, in the present embodiment, in synchronization with the pulse P _E of the pulse encoder 12 is transmitted in the object detection circuit 42, since taking out image signals for one line, the influence of the conveying speed Can be reduced. According to experiments by the present inventors, synchronization with image input could be achieved even at a transport speed of 15 m / min or more.

FIG. 6 shows a work posture discriminating device using the visual device shown in FIG. 1, and includes a judgment circuit 47 and a teaching device 48 in addition to the above visual device.

In this configuration, first, the work W is transported in a forward posture in which the base W2 side is the top, the image data during the object detection period T is stored in the image memory 46, and the stored image data is stored in the image memory 46. The image is displayed on the screen of the teaching device 48 to obtain a sample image. Next, on this screen, a window WIND having a predetermined area and a predetermined shape is set in a characteristic portion capable of determining the posture (whether forward or reverse) of the work W, and the address of the set window WIND is set. Judgment circuit 47
Teach. This characteristic portion is one non-overlapping area when the left-right inverted image of the sample image is superimposed on the sample image, and in the case of the work W, as shown in FIG. Set window WIND near the periphery of.

After the preparation described above, the posture of the work W sequentially transferred from the work supply line A to the transfer device 10 is determined. During the object detection period T, the determination circuit 47 to which the address of the window WIND has been set determines whether the image data stored in the image memory 46 is to be stored in the image memories M ₁ , M ₁ at the second timing when the period T ends. _2, M read in ₃ · · · · Mn order of the image data, and check the image data in the window WIND, counted the number of pixels "black pixels", the number of pixels is the threshold value or less In the case of, it is determined that the workpiece W is in the forward orientation, for example, a pass signal is generated. Send out. This threshold value is set in the determination circuit 47 by the teaching device 48.

The determination of the work posture based on the window setting is performed when one of the work shapes in the X direction, that is, the work length direction (work moving direction) is different from the others, that is, the direction of the work is different. In the case of a certain work, its posture can be determined.

In this embodiment, a two-dimensional image of the work W is stored in an image memory.
After the data is stored in 46, the above-described posture determination is performed. Therefore, the work transfer interval is determined by the processing speed of the work posture determination device. As shown in FIG.
If the image data of the next work W is stored in the other image memory while the determination circuit 47 is reading the image data stored in one image memory, the number of work processes per unit time is increased. be able to. In the figure, 49F and 49R are changeover switches, which perform a switching operation in synchronization with the first timing or the second timing of the object detection circuit 42. Note that the number of image memories is not limited to two.

FIG. 9 shows another example of the work posture discriminating apparatus, in which an image memory 50 for teaching and a template memory 5 are provided.
1, a matching memory 52 and a judgment circuit (including a comparison circuit) 53 are provided.

In this configuration, first, the work W moving in the forward direction is imaged by the CCD camera 30, the two-dimensional image data is stored in the image memory 50, and the image data is transmitted from the image memory 50 to the teaching device. The image is read out to the screen 48 and the image of the work W is displayed on the screen of the teaching device 48. A vertically-oriented (long in the Y-direction) rectangular frame extending outside and inside the image is set on both sides of a predetermined position on the image displayed on the screen, that is, a change position where the shape changes. In this example, as shown in FIG. 11, a rectangular frame 61 is set at the base W2 of the work W, and a rectangular frame 62 is set at the base W2 of the work W. The rectangular frames 61 and 62 have different coordinates in the X direction, but have the same size and the same coordinates in the Y direction. The set image data of the rectangular frame 61 (FORWARD template) and the image data of the rectangular frame 62 (BACKWARD template) are stored in the template memory 51.

After the preparation described above, the posture of the work W sequentially transferred from the work supply line A to the transfer device 10 is determined. The image data output from the object detection circuit 42 is stored in the matching memory 52. Matching memory 52
Receives image data for one line sequentially sent by the object detection circuit 42, and stores matching image data that can determine the match / mismatch with the template.
The determination circuit 53 compares the template stored in the template memory 51 with the matching image data captured by the matching memory 52 at each timing when the object detection circuit 42 outputs one line of image data. A difference in the number of “black pixels” is detected, and if the difference is equal to or smaller than the threshold value, it is determined that there is matching (matching). That is, first, the matching image data stored in the matching
Performs an operation to compare with the ARD template, and if a match is obtained, then a matching memory that is sequentially updated
The matching image data in 52 is compared with the BACKWARD template, and the determination circuit 53 determines that the matching order is
If the order of the D template is followed by the order of the BACKWARD template, the posture of the workpiece W is determined to be in the forward direction, and a pass signal is generated. Otherwise, a reject signal is generated.

Specifically, in order to prevent the determination accuracy from lowering due to noise, for example, the width of the rectangular frames 61 and 62 is set to 5 dots,
As shown in FIG. 10, the FORWARD template is stored in a template memory 51 including n (n = 5 in this example) line memories 51 _{M1 to} 51 _M5 . Similarly, although not shown, the BACKWARD template is stored in the other n line memories. The matching memory 52 is a line memory 52 _{M1 to} 52 _M5 having the same size as the template memory 51.
Is a first-in first-out (FIFO) memory. These line memories have a memory capacity for storing image data for one scanning line of the CCD camera 30. 54 is CCD
This is a pulse generation circuit that gives a timing to read data of one pixel of the camera 30. Each time the line memories 52 _{M1 to} 52 _M5 of the matching memory 52 receive the pulse of the pulse generation circuit 54, they send the data of one pixel stored first to the memory of the preceding stage and send out the data of the subsequent memory. 1
The pixel data is stored.

Judging circuit 53, the data of the template memory 51 _M1 data of the line memory 52 _M1 in the matching memory 52, the data of the line memory 52 _M2 template
The data of the memory 51 _{M2 and} the data of the line memory 52 _M3 are _{converted into} the data of the template memory 51 _M3 and the line memory.
52 _M4 data in template memory 51 _M4 data
Line memory 52 _M5 data to template memory 51
_Check with _M5 data.

With such a hardware configuration, the above-described collation operation can be performed while image data for one scanning line is being captured from the CCD camera 30, so that the determination processing time can be shortened.

9 and 10, the order in which the image data changes in the direction perpendicular to the work moving direction (X direction), that is, in the Y direction (height direction) (from large to small, small to small). From large to large), there is an advantage that the work posture can be determined without waiting for the detection of the rear end of the work W, and the influence of the length of the work image in the X direction can be obtained. There is an advantage that the pulse encoder 12 and the synchronization circuit 41 described above are not required because they are not received.

In the case of the work W in the above embodiment, the number of rectangular frames set in the work characteristic portion is two, but the characteristic portion is three.
Even if there are more than two, or if there are two characteristic parts, to improve the determination accuracy, set a rectangular frame at three or more places,
The image data may be stored in the template memory.

〔The invention's effect〕

As described above, the visual device of the present invention uses a line-type image sensor to obtain a two-dimensional image of a work, so that the image input speed and the processing speed of image data are high,
Restrictions on the work speed and the work transfer interval can be relaxed as compared with the related art. In addition, the work posture determination device based on the window setting of the present invention uses the image data of the visual sensor, and the window is set to a characteristic portion of the work.
Since the posture can be reliably determined and the work posture determination device based on the template setting determines the posture based on the change in the height direction of the transferred work, it is necessary to synchronize the input image with the work transfer speed. There are no advantages and high processing capacity can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a work transfer line installed by the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG.
The figure is a signal time chart for explaining the above embodiment,
FIG. 4 is a diagram showing an example of a work in the above embodiment, FIG. 5 is a diagram showing a screen of a display device in the above embodiment, FIG. 6 is a block diagram showing an embodiment of the second invention, FIG. Fig. 7 shows the second
FIG. 8 is a block diagram showing a modification of the invention of FIG. 8, FIG. 8 is a diagram for explaining a window set in the jealous view example of FIG. 6,
9 is a diagram showing an embodiment of the third invention, FIG. 10 is a diagram showing a specific example of the embodiment shown in a block diagram in FIG. 9, and FIG. 11 is set in the embodiment of FIG. FIG. 6 is a diagram for explaining a template to be used. 10 ... Transfer device, 12 ... Pulse encoder, 20 ... Light source, 30 ... CCD camera, 41 ... Synchronous circuit, 42 ... Object detection circuit, 43, 45 ... Memory switching circuit, 46, 46A, 50 ......
Image memory, 47, 53 ... Judgment circuit, 48 ... Teaching device, 51
…… Template memory, 52 …… Matching memory, M _{1 to} M _n …… Line image memory.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23P 19 / 00,301 B23P 21 / 00,307

Claims (6)

(57) [Claims] A line type image sensor for picking up an image of a workpiece transferred in a direction intersecting with the line direction, monitoring one line of image data sequentially transmitted by the image sensor, and detecting a change in the workpiece based on an initial change. Detect the tip,
An object detection circuit for detecting the rear end of the work by the change to the same image data as before the change, and an image memory for sequentially storing the image data while the object detection circuit detects the work. Visual device for mobile work. 2. The image data stored in the image memory is image data extracted from the image data sent from the image sensor in synchronization with a pulse output of an encoder attached to a device for transferring a work. The visual device for a moving work according to claim 1, wherein the visual device is provided. 3. A line-type image sensor for picking up an image of a workpiece conveyed in a direction intersecting with the line direction, and monitoring one line of image data sequentially sent out by the image sensor. And an object detection circuit for detecting the rear end of the work by changing to the same image data as before the change, and sequentially storing the image data while the object detection circuit detects the work. A visual device having an image memory, a teaching device for teaching a sample image of a work, sequentially reading image data in the image memory, and determining a work posture from image data in a window taught by the teaching device A window, wherein the window is set to one non-overlapping area when the sample image is superimposed on the sample image with a front / reverse image of the sample image. Work attitude determination apparatus characterized by being. 4. An image processing apparatus comprising: at least two image memories; and a memory switching circuit, which synchronizes one of the image memories with an object synchronously with a work leading end detecting timing or a work trailing end detecting timing of the object detecting circuit. 4. The work posture discriminating apparatus according to claim 3, wherein the discriminating circuit is connected to the discriminating circuit while the other image memory is separated from the discriminating circuit and connected to the object detecting circuit. 5. A line type image sensor for picking up an image of a workpiece transferred in a direction intersecting with the line direction, monitoring one line of image data sequentially transmitted by the image sensor, and detecting a change in the workpiece by an initial change. Detect the tip,
An object detection circuit for detecting the rear end of the work by changing to the same image data as before the change, an image memory for sequentially storing the image data while the object detection circuit detects the work, A teaching device that reads out image data in the image memory when the image is transferred in the posture described above and teaches a sample image of the work, and outputs image data of at least the first and second work characteristic portions taught by the teaching device. A template memory for storing the image data, a matching memory for receiving the image data, and a determination circuit for comparing the matching image data stored in the matching memory with the image data of the work characteristic portion to determine whether or not there is matching between the two. Wherein the image data of the first and second work characteristic portions is based on the shape change point of the sample image. The image data in a rectangular frame which is set on one end side of the image and the other end side of the image and extends over the work image portion and the non-work image portion. A work posture determining apparatus for determining a work posture based on a matching order with image data. 6. The template memory has at least a plurality of line memories for storing image data of a first characteristic portion and a plurality of line memories for storing image data of a second characteristic portion. The matching memory is a first-in, first-out operation memory composed of line memories corresponding to the line memories, respectively. Each time the image sensor sends out one scan line of image data, the determination circuit determines the corresponding line memory. 6. The apparatus according to claim 5, wherein the data stored in the memory is compared with each other.