JPH048427A - Visual device for moving work and work attitude discrimination device - Google Patents

Abstract

PURPOSE:To carry out the discrimination of a work attitude accurately at a high speed in a short period of time by detecting the point of the work based on the initial change of an image data for one-line from an image sensor, and by storing the image data that detects the work in an image memory in order. CONSTITUTION:A line-shaped image sensor 30 is put on a carrier device 10, and takes image of a work W irradiated by a light source 20, and its image data is fed in the form of a signal I, and the image data is input to a material detection circuit 42 of an image processor 40. An image data input from a first timing that the condition where 'black picture element' does not exist in the image data is transferred to the condition where the 'black picture element' exists, is fed by the material detection circuit 42, and the feeding of the input image data is stopped at a second timing that the condition where the 'black picture element' exists is transferred to the condition where the 'black picture element' is extinguished. The image data fed by the material detection circuit 42 is stored in image memories M1, M2, M3...., and the data is read by a judging circuit 47, and the attitude of the work W is thus judged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a visual device and a workpiece posture determining device for obtaining a workpiece image of a moving workpiece.

[Conventional technology]

On an automatic assembly line, etc., if the parts to be fed (hereinafter referred to as workpieces) have a direction, during feeding,
The posture is determined, and the workpieces with bad posture are removed by a sorting mechanism.

[Problem to be Solved by the Invention] This determination of the workpiece posture has conventionally been carried out using mechanical means such as providing an attachment on the workpiece feeding path. In addition to being impossible to distinguish, changing the workpiece was troublesome because if the shape of the workpiece changed, the attachment had to be changed as well.

In recent years, image sensors and image processing technology for processing their image output have developed, so it is now possible to image a moving work using a two-dimensional image sensor (especially a CCD camera) and process the image output of this image sensor. A method has been proposed to determine the workpiece posture by
e is large, and it takes time to process the image output, so there is a problem that the workpiece transfer speed and workpiece transfer interval are restricted, and the processing capacity of the drive assembly line etc. cannot be sufficiently increased. In addition, in order to provide timing for the image processing device to capture image data, it is necessary to separately install a position sensor that detects when the workpiece enters the field of view of the image sensor.

The present invention has been made in view of the above problems, and uses a line-type CCD image sensor with a high image input speed to obtain a two-dimensional image of a moving workpiece without using the position sensor. Even in the case of workpiece shapes that are difficult to determine by the mechanical means described above, the posture can be determined at high speed.
It is an object of the present invention to provide a visual device for a moving workpiece and a workpiece posture discrimination device that can accurately perform the determination in a short time and without being affected by the workpiece movement speed.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a visual device for moving workpieces, which includes a line-type image sensor that images a workpiece being transferred in a direction intersecting the line direction; An object detection circuit that monitors one line of image data that is sent out sequentially, detects the leading edge of the workpiece based on the first change in the image data, and detects the trailing edge of the workpiece based on the change to the same image data as before the change; The object detection circuit is configured to include an image memory that sequentially stores the image data while detecting the workpiece, and in claim 2, the image data stored in the image memory is based on the image data sent out by the image sensor. The image data is taken out in synchronization with the pulse output of an encoder attached to the device that transports the workpiece.

A workpiece posture determining device according to a third aspect of the present invention sequentially reads a sample image of a workpiece with a teaching device and the image data in the image memory, and determines the workpiece posture from the image data in the window taught by the teaching device. A determination circuit is provided, and the window is configured to be set to one non-overlapping SJ[[ when a front and back inverted image of the sample image is superimposed on the sample image.

In a fourth aspect of the present invention, the discriminating device has at least two image memories and a memory switching circuit is provided, and the memory switching circuit switches one of the image memories in synchronization with the workpiece front end detection timing or the workpiece rear end detection timing of the object detection circuit. 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.

A workpiece posture determination device according to a fifth aspect of the present invention includes a line-type image sensor that images a workpiece being transferred in a direction crossing the line direction, and a line-type image sensor that monitors one line of image data sequentially sent out by the image sensor and detects the first image of the workpiece. An object detection circuit detects the front end of the workpiece by a change in the image data, and detects the rear end of the workpiece by a change to the same image data as before the change. an image memory for teaching that sequentially stores data; a teaching device that teaches a sample image of the work when the work is transferred in a predetermined posture; and at least a first and second work that is taught by the teaching device. A template memory that stores image data of the characteristic part, a matching memory that manually inputs the image data, and a matching image data for matching in this matching memory is compared with the image data of the characteristic part of the workpiece, and the matching of the two is performed. The image data of the first and second work characteristic portions are set on the leading edge side and the trailing edge side of the image, respectively, from the shape change point of the sample image, and the image data of the first and second workpiece characteristic portions are set on the image front side and the image rear end side, respectively, to separate the workpiece image portion and the non-workpiece image. The image data is image data within a rectangular frame extending over a portion, and the determination circuit is configured to determine the workpiece posture based on the matching order of both the templates and the image data in the matching memory.

Further, in claim 6, the template memory includes at least a first line memory storing image data of the first work characteristic portion and a second line memory storing image data of the second work characteristic portion. The matching memory is a first memory which is located in front and rear stage relation and performs first-in, first-out operation.
and a second line memory, and each time one pixel worth of data is read from the image sensor, both line memories send out the first stored one pixel worth of data to the determination circuit. The determination circuit is configured to repeat the operation of comparing the data sequentially sent out from the first line memory and the second line memory of the matching memory with the data at the address in the corresponding line memory of the template memory. And so.

[Effect]

In the visual device of the present invention, a line-type image sensor images the work to be transferred, and the object detection circuit detects the tip of the work by the first change in the image data of the line. However, the rear end of the workpiece is detected by the change to the same image data as before the change, and while the object detection circuit is detecting the workpiece, the image data is sequentially stored in the image memory.

In the workpiece posture determination device using window settings of the present invention,
A teaching device is used to teach a window in one non-overlapping area when a front and back inverted image of the sample image is superimposed on a sample image, and this taught window is set in a judgment circuit, and the judgment circuit takes in the window. The workpiece posture is determined based on whether the image data within the window of the workpiece image is above or below a threshold value among the image data of the workpiece.

In addition, in the workpiece posture determination device of the present invention that uses image data of the workpiece characteristic portion as determination data, the workpiece image portion and the non-workpiece image portion are detected from the shape change point of the sample image to the image front end side and the image rear end side, respectively. The image data within the rectangular frame (the first and second
The 0 judgment circuit stores the image data (image data of the characteristic part of the workpiece) in the template memory.
Data for all pixels of the image sensor that is updated pixel by pixel,
It is determined whether or not there is matching with the image data of the first and second workpiece characteristic parts, and the order of matching is, for example, matching with the image data of the first workpiece characteristic part, then matching with the image data of the second workpiece characteristic part. If the workpiece posture is matched with the image data of , it is determined that the workpiece posture is the desired posture.

〔Example〕

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

In FIG. 1, reference numeral 10 denotes a conveyor, which automatically transfers a work W (one example is shown in FIG. 4) from a work supply line A and sends it to a sorting line B side. 12
is a pulse encoder that is pivotally connected to the pulley 11 of the conveying device 10. This workpiece W has a shape consisting of a base part W1 and a stand part W2 that projects from one end surface of the base part W1 with a reduced diameter. The forward attitude of W is assumed.

Reference numeral 20 denotes an illumination light source that illuminates the workpiece W transferred to the transport device 10 from a horizontal direction perpendicular to the workpiece movement 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 across the conveyance device 10, is transferred onto the conveyance device 10, and is irradiated by the light source 20. An image of the workpiece W being moved is taken, and the image data is sent out in the form of a signal (2), and this image data is input to the object detection circuit 42 through the synchronization circuit 41 of the image processing device 40 shown in FIG. As the CCD camera 30, for example, effective pixel count: 128 pixels, clock frequency: IM
H2, image input time: 250 μsec is used. 43 and 45 are memory switching circuits, and 46 is an image memory. This image memory 46 consists of n image memories (line memories) M1 to Mn. 50 is a display device.

The CCD camera 30 is arranged so that the direction of its pixel array (line direction) is as shown by the broken line in FIG. It outputs 1947 minutes of image data at regular intervals. C
The image data sent out from the CD camera 30 is input to a synchronization circuit 41, and this synchronization circuit 41 synchronizes with the rising and falling edges of the pulse P7 sent out by the encoder 12.
The object detection circuit 42 outputs 7 minutes of image data to the object detection circuit 42.The object detection circuit 42 receives the input from the first timing when the image data changes from a state where there is no "black pixel" to a state where there is a "black pixel". Transmission of the input image data is interrupted at a second timing when the image data is started to be transmitted and the state in which the "black pixel" exists shifts to the state in which the "black pixel" disappears. The object detection circuit 42 detects the workpiece W during both of these timings, and during this workpiece detection period (referred to as period T), every time it receives one line of image data from the synchronization circuit 41, the memory A switching signal S-5 is sent to the memory switching circuit 43. The image data sent out by the object detection circuit 42 is stored in image memories M+, Mz, M8, . . . that are sequentially designated by the memory switching circuit 43. The display device 50 sends the memory switching signal SW2 to the memory switching circuit 4.
5, image memories M+, Mz, M3,
Sequentially reads out the image data stored in...
Display on screen.

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

In this embodiment, since the line-type image sensor 30 is used, the image input speed is fast, and since only the work image is captured, the time required to process the image data is short, compared to the case where a two-dimensional image sensor is used. Restrictions on workpiece transfer speed and workpiece transfer interval can be relaxed.

In addition, when obtaining a two-dimensional image of the moving workpiece W using a line-type image sensor, the transport speed of the transport device 10 is changed in the length direction (X) of the two-dimensional image.
In this embodiment, the pulse P sent out by the pulse encoder 12 in the object detection circuit 42 is
Since the image signal for one line is extracted in synchronization with I, the influence of the above-mentioned conveyance speed can be reduced. According to experiments conducted by the present inventors, even when the conveyance speed is 15 m/min or more, the image signal is not synchronized with the image input. I was able to synchronize.

FIG. 6 shows a work posture determining device using the visual device shown in FIG. 1, which includes a determination circuit 47 and a teaching device 48 in addition to the visual device.

In this configuration, first, the workpiece W is transported in a forward posture with the table W2 at the top, image data during the object detection period T described above is accumulated in the image memory 46, and the accumulated surface image is The data is projected onto the screen of the teaching device 48 to obtain a sample image. Then, on this screen,
A window WI with a predetermined area and a predetermined shape is installed in a characteristic part that can determine the posture of the workpiece W (forward or reverse direction).
ND is set, and the determination circuit 47 is taught the address of the set window WIND. This characteristic part 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 workpiece W, as shown in FIG. A window WIND is set near the circumferential surface of.

After the above preparations are made, the postures of the workpieces W that are sequentially transferred from the workpiece supply input A onto the transport device 10 are determined. The determination circuit 47, which is set with the address of the window WIND, uses the image memory 4 during the object detection period T.
At the second timing when the period T ends, the image data stored in the image memories M, , M, , M
! ...Read out in the order of Mn, check the image data in the window WIND among the image data, count the number of "black pixels", and if this number of pixels is less than the threshold value, determines that the workpiece W is in a forward orientation and generates, for example, a pass signal, and if it is equal to or greater than a threshold value, determines that the workpiece W is in a reverse orientation and sends out a fail signal. This threshold value is set in the determination circuit 47 by the teaching device 48.

This determination of the workpiece posture based on the window setting is performed when there are multiple shape change parts in the workpiece shape in the X direction, that is, the workpiece length direction (workpiece movement direction), but one of them is different from the others. If there is a certain work, its posture can be determined.

In this embodiment, a two-dimensional image of the workpiece W is stored in the image memory 4.
6 and then performs the above posture determination, the workpiece transfer interval is determined by the processing speed of this workpiece posture determination device.As shown in FIG. 7, an image memory 46A is added and the determination circuit 47 is If the image data of the next workpiece W is stored in the other image memory while the image data stored in the image memory is being read out, the number of workpieces processed per unit time can be increased. In the figure, 49F and 49R are changeover switches, which perform a switching operation in synchronization with the above-described first timing or second timing of the object detection circuit 42. Note that the number of image memories is not limited to two.

Figure 9 shows another example of the workpiece posture discrimination device.
Image memory 50 for teaching, template memory 51
, a matching memory 52, and a determination circuit (including a comparison circuit) 53.

In this configuration, first, a CCD camera 30 images a work W moving in a forward posture, the two-dimensional image data is stored in an image memory 50, and then the image data is transferred from this image memory 50 to a teaching device. The image of the workpiece W is read out to the teaching device 48 and displayed on the screen of the teaching device 48. A vertical rectangular frame (long in the Y direction) extending between outside and inside the image is set at a predetermined position on the image displayed on the screen, that is, on both sides of the changing position where the shape changes. In this example,
As shown in FIG. 11, a rectangular frame 61 is placed on the base W2 of the workpiece W.
A rectangular frame 62 is set at the base W2 of the workpiece W. These rectangular frames 61 and 62 have different coordinates in the X direction, but the size and
The coordinates in the Y direction are the same. The image data of the set 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 above preparations are made, the postures of the workpieces W that are sequentially transferred from the workpiece supply line A onto the transport device IO are determined. The image data output by the object detection circuit 42 is stored in a matching memory 52. The matching memory 52 receives image data for lines sequentially sent out by the object detection circuit 42 and stores matching image data that can be used to determine whether or not it matches the template. The determination circuit 53 compares the template stored in the template memory 51 with the matching image data taken in by the matching memory 52 every time the object detection circuit 42 outputs one line of image data. The difference in the number of "black pixels" is detected, and if this difference is less than a threshold value, it is determined that there is matching (matching), and if it is more than the threshold value, it is determined that it is mismatched. Sawachi,
First, the matching image data stored in the matching memory 52 is compared with the FORWARD template, and if matching is achieved, then the matching image data in the matching memory 52, which is updated sequentially, is compared with the FORWARD template. Comparing it with the template, the determination circuit 53 determines that the posture of the workpiece W is in the forward direction when the matching order is first, the FORWARD template, and then the BACKWARD template, and issues a pass signal. , otherwise generates a fail signal.

Specifically, in order to prevent the determination accuracy from decreasing due to noise, for example, the width of the rectangular frames 61 and 62 is set to 5 dots, and as shown in FIG. Template consisting of line memory 51□~51.4$
The FORWARD template is stored in the memory 51. Similarly, although not shown, the BACKWARD template is stored in other n line memories. The matching memory 52 is a line memory 52 .of the same size as the template memory 51 . , ~52 days, is a first-in first-out FIFO) memory. These line memories have a memory capacity to store image data for one scanning line of the CCD camera 30. 54 is a pulse generation circuit that provides timing for reading data for one pixel of the CCD camera 30. Each line memory 5281 to 52.4- of the matching memory 52 stores the first stored one each time it receives a pulse from the pulse generating circuit 54.
Data for a pixel is sent to the memory in the previous stage, and data for one pixel sent out from the memory in the latter stage is stored.

The judgment circuit 1553 converts the data in the line memory 52MI in the matching memory 52 into the data in the template memory 51□, the data in the line memory 52MZ into the data in the template memory 51xz, and the line memory 52MI into the template memory 51□.
Data in memory 52.41 is transferred to template memory 51
83 and the data in the line memory 52 are compared with the data in the template memory 51M4, and the data in the line memory 52□ are compared with the data in the template memory 51M, respectively.

With such a hardware configuration, the above matching operation can be performed while one scanning line of image data is being taken in from the CCD camera 30, so the determination processing time can be shortened.

In the workpiece posture determination apparatus shown in FIGS. 9 and 10, the order of changes in image data in the direction perpendicular to the workpiece movement direction (X direction), that is, the Y direction (height direction) (
Since the workpiece posture is determined from large to small, small to large), there is an advantage that the workpiece posture can be determined without waiting for the rear end of the workpiece W to be detected, and in addition, the workpiece posture can be determined from the X direction of the workpiece image. Since it is not affected by the length of , there is an advantage that the pulse encoder 12 and the synchronization circuit 41 described above are not required.

Note that in the case of the workpiece W in the above embodiment, two rectangular frames are set for the work feature parts, but the determination accuracy can be improved even if there are three or more feature parts or if there are two feature parts. Therefore, rectangular frames may be set at three or more locations, and the image data may be stored in the template memory.

〔Effect of the invention〕

As explained above, the visual device of the present invention uses a line-type image sensor to obtain a two-dimensional image of the workpiece.
Image input speed and image data processing speed are high, and restrictions on workpiece speed and workpiece transfer interval can be relaxed compared to conventional methods.

Further, the work posture determination device using window settings of the present invention utilizes the image data of the above-mentioned visual sensor,
Since the window is set on a characteristic part of the workpiece, if the shape of the workpiece is not symmetrical, its posture can be reliably determined. Since the posture is determined based on the change, there is an advantage that there is no need to synchronize the input image and the workpiece transfer speed, and high processing capacity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a work transfer line installed according to the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG.
The figure shows a signal time chart for explaining the above embodiment.
FIG. 4 is a diagram showing an example of the content in the above-mentioned example, FIG. 5 is a diagram showing the screen of the display device in the above embodiment, and FIG. 6 is a diagram showing the second example.
FIG. 7 is a block diagram showing a modification of the second invention, FIG. 8 is a diagram for explaining the window set in the jealous example of FIG. 6, Figure 9 is a diagram showing an embodiment of the third invention, Figure 10 is a diagram showing a specific example of the embodiment shown in the block diagram in Figure 9, and Figure 11 is a template set in the embodiment of Figure 9. FIG. 10--Transfer device, 12-Pulse encoder, 20-
Light source, 30--CCD camera, 41--synchronous circuit, 4
2-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, M1-M1-line image memory. Figure 1

Claims (6)

[Claims] (1) A line-type image sensor that images a workpiece that is being transferred in a direction that intersects the line direction.This image sensor monitors one line of image data that is sent out sequentially, and detects the tip of the workpiece based on the first change in the image data. an object detection circuit that detects the rear end of the workpiece based on a change to the same image data as before the change; and an image memory that sequentially stores the image data while the object detection circuit detects the workpiece. A visual device for moving workpieces, which is characterized by: (2) The image data stored in the image memory must be image data that is extracted in synchronization with the pulse output of the encoder attached to the device that transports the workpiece, out of the image data sent out by the image sensor. The visual device for moving workpieces according to claim 1, characterized in that: (3) A line-type image sensor that images the workpiece being transferred in a direction that intersects the line direction, and monitors one line of image data sequentially sent out by this image sensor, and detects the first change in the image data at the tip of the workpiece. an object detection circuit that detects the rear end of the workpiece based on a change to the same image data as before the change, and an image memory that sequentially stores the image data while the object detection circuit detects the workpiece. a visual device comprising a visual device, a teaching device for teaching a sample image of the workpiece, and a determination circuit for sequentially reading image data in the image memory and determining the workpiece posture from the image data in the window taught by the teaching device. A workpiece posture determining apparatus, wherein the window is set to one non-overlapping area when a front and back inverted image of the sample image is superimposed on the sample image. (4) It has at least two image memories and a memory switching circuit, and the memory switching circuit switches one of the image memories to the object detection circuit in synchronization with the workpiece front end detection timing or workpiece rear end detection timing of the object detection circuit. 4. The workpiece posture discriminating device according to claim 3, wherein the other image memory is separated from the discriminating circuit and connected to the discriminating circuit, and the other image memory is separated from the discriminating circuit and connected to the object detecting circuit. (5) A line-type image sensor that images the workpiece being transferred in a direction that intersects with the line direction.This image sensor monitors one line of image data that is sequentially sent out, and detects the tip of the workpiece based on the first change in the image data. an object detection circuit that detects the rear end of the workpiece by changing the image data to the same image data as before the change; an image memory that sequentially stores the image data while the object detection circuit is detecting the workpiece; A teaching device that reads image data in the image memory when the workpiece is transferred in a predetermined posture and teaches a sample image of the workpiece, and at least first and second workpiece characteristic portions taught by the teaching device. A template memory that stores image data, a matching memory that receives the above image data, and compares the matching image data stored in this matching memory with the image data of the work characteristic portion to determine whether or not there is a match between the two. a determination circuit for determining the first and second
The image data of the workpiece characteristic part is image data within a rectangular frame that is set at one end of the image and the other end of the image from the shape change point of the sample image, respectively, and extends across the workpiece image part and the non-workpiece image part, The workpiece posture determining device is characterized in that the determination circuit determines the workpiece posture based on the matching order of the image data of the two workpiece characteristic portions and the matching image data. (6) The template memory includes at least a plurality of line memories storing the image data of the first characteristic part and a plurality of line memories storing the image data of the second characteristic part.
The matching memory is a first-in, first-out operation memory consisting of line memories corresponding to each of the above-mentioned line memories. ,
6. The workpiece posture determining apparatus according to claim 5, wherein the data stored in the corresponding line memories are compared with each other.