JP2003208605A - Photographing object feed device for image processing device and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a conventional problem that an image is blurred in an ordinary photographing means to photograph an object moving continuously at a fixed high speed when increasing the number of photographing processing per unit time. <P>SOLUTION: A target value of feed speed is varied so that it becomes a low speed in a part where the photographing object is in the vicinity of the center of a field of view of the photographing device and it becomes a high speed in a process where the photographing object is being moved up to the vicinity of the center of the field of view of the photographing device. Many objects are photographed per unit time to obtain a satisfactory image for performing image processing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention captures a large number of imaged objects per unit time and performs image processing such as measurement and pattern matching for the purpose of inspection and adjustment.
The present invention relates to an image pickup object feeding device that carries an image pickup object into and out of a field of view of an image pickup apparatus.

[0002]

2. Description of the Related Art An image pickup apparatus for inputting image data of an object to an image processing apparatus has a limited field of view. When automatically feeding an object into the field of view of the image pickup apparatus, it has not been used to control the movement of the feeding apparatus by using a dedicated control device in consideration of cooperation with the image processing apparatus. That is, the movement of the feeding device was controlled by the general-purpose control device.

Therefore, the target of the feed speed has come to be set to a constant speed. For applications where the number of objects to be handled per unit time is small, it was also done to temporarily stop. However, in that case, the number of processes per unit time cannot be increased.

In order to capture an image without stopping, it is necessary to precisely control the shutter release timing.
That is, the shutter must be released at the timing when the object to be imaged is located exactly in the center of the field of view. For that purpose, a sensor such as a photoelectric tube may be prepared, the passage of the object may be detected at a position slightly in front, the delay of signal transmission may be taken into consideration, and an instruction may be issued to the image pickup apparatus at an appropriate timing.
Since the feed speed is a constant speed at least as a target speed, the time required to move the object can be accurately calculated if the positional relationship between the sensor that detects the passage of the object and the imaging device is known. is there.

Further, in order to pick up an image of a moving object, there is a problem that an ordinary image pickup means blurs, blurs or doubles an image. In order to deal with this, a method of making the exposure time as short as possible has been adopted. That is, to increase the shutter opening / closing speed.

The reduction of the exposure time causes another problem that the obtained image becomes dark and unclear. Improvements have been made in this respect in terms of both increasing the sensitivity of the image pickup device used in the image pickup apparatus and brightening the illumination that illuminates the image pickup target. A strobe discharge tube is often used for bright illumination.

[0007]

As the number of times of imaging per unit time increases, it becomes difficult to obtain a good image by the method of sending an object at a constant speed.

The precision of the shutter timing must also be improved. When the moving speed of the object becomes faster, even if there is a slight error in the shutter timing, a long distance error occurs at the position of the object in the error time. It becomes difficult to catch the target object at the right position in the field of view.

When the moving speed of the object becomes faster, the shutter opening / closing speed is required to be further increased in order to reduce the disturbance of the image caused by the image of the moving object.

At the same time as the shutter opening / closing speed is increased, the exposure time is shortened accordingly. The development of even more sensitive image sensors and the development of stronger strobe discharge tubes are continuing. However, such state-of-the-art devices are inevitably expensive and difficult to obtain. Even with the latest technology, the minimum exposure time for obtaining a clear image is strictly present in any age.

The limit of exposure time is also the limit of shutter opening / closing speed. The result is that the number of processings per unit time cannot be increased by limiting the moving speed within the range where the image disturbance caused by capturing the moving object does not adversely affect the image processing in the post process. Lead.

[0012]

SUMMARY OF THE INVENTION According to the present invention, the feed speed, which has been conventionally set at a constant speed, becomes slow at the timing when the object to be imaged is positioned near the center of the field of view of the image pickup device, and the object to be imaged is viewed in the field of view of the image pickup device. By making the target value of the feed rate variable so that the speed is high in the process of moving to near the center, a large number of objects are imaged per unit time, and a good image for image processing is obtained. It is an imaging object feeding device in consideration of cooperation with an image processing device so as to be performed. This is the imaging object feeding device of claim 5, and the method is the method of claim 1.

By making the feed speed variable, it is possible to keep the feed speed low at the time of image pickup without reducing the average feed speed. The number of images taken per unit time depends on the average feed rate if the distance between the objects is almost constant,
It does not depend on the maximum speed or the minimum speed. That is, unless the average feed speed is reduced, the number of times of imaging per unit time does not decrease.

On the other hand, by holding down the feed speed at the time of image pickup, the shutter opening / closing speed used is slower, which is used in the conventional method when the number of image pickups per unit time is smaller. It doesn't matter. Therefore, the exposure time can be relatively long, and a clear image can be obtained.

In order to repeat rapid acceleration and deceleration, a servomotor can be used as an actuator, which is the imaging object feeding device of claim 6, and the method is the method of claim 2.

As an advantage of using the servomotor, it can be assumed that no slippage or the like occurs between the constituent members of the feeding device existing between the servomotor shaft and the object to be imaged and between the feeding device and the object to be imaged. It can also be pointed out that the shutter timing can be determined without an external sensor if the deviation occurs or if the deviation is within the allowable error range. This is the imaging object feeding device of claim 7, and the method is the method of claim 3. If the position and speed of the imaged object can be controlled with sufficient accuracy,
Needless to say, the shutter timing can be determined without an external sensor even when the servo motor is not used as the actuator.

On the other hand, by feeding back the target position in the measurement result of the image, it is possible to correct the feed deviation in real time. That is, assuming that the pitch between the objects is constant, the amount of feed deviation can be calculated by calculating the difference between the position of the imaged object in the scheduled image and the position of the imaged image. It becomes possible to know. This is the imaging object feeding device according to claim 8, and the method is the method according to claim 4.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A connector pin inspection device to which the present invention is applied will be described below.

The connector pin inspecting device is a device for judging whether the connector pin 8 produced by the connector pin processing device 1 is good or bad by the image processing such as the shape and interval of the connector pin 8.

The connector pin processing apparatus 1 punches a continuous material by press molding to simultaneously produce a connector pin guide 25 and a connector pin 8 as shown in FIG.

FIG. 1 shows an outline of this inspection apparatus. This device has a structure in which the machine and the control device 6 are integrated, and the control computer, which is the main body of the control device 6, is also installed in the machine.

The workpiece enters the inspection device with the connector pin 8 attached to the connector pin guide 25 from the connector pin processing device 1. The intervals between the connector pins 8 that are products are substantially adjusted to a constant distance called a pitch.

The connector pin 8 is a connector pin guide 25.
The connector pin guide 25 is conveyed by the feed roller 26 under pressure on the inlet side pressing cylinder 2. The feed roller 26 is driven by the servo motor 7.

The part in front of the inlet side presser cylinder 2 is
The slack portion 9 serves as a play for absorbing a speed difference between the connector pin processing device 1 and the inspection device. The sensor tower 3 is a collection of sensors installed at an appropriate height.
It is used to check whether the slack portion 9 is within a certain range.

A portion between the inlet side holding cylinder 2 and the outlet side holding cylinder 4 is a portion controlled by the servo motor 7.

The camera 5 located substantially in the center from the inlet side holding cylinder 2 to the outlet side holding cylinder 4 is the image pickup device of the image processing apparatus which is the core of the present inspection apparatus. The main body of the image processing apparatus is substantially the same as the control computer and is realized by software.

FIG. 2 shows an outline of the control computer of the inspection apparatus. Two built-in personal computers called a main PC 10 and an image processing PC 11 are the main constituent elements.

The main PC 10 is a personal computer for performing human-machine interface such as data input and monitor screen display and sequence control. A liquid crystal display 12, a keyboard 13 and a mouse 14 are connected as input / output devices. Also, use a model that can connect to the Internet for LAN connection with other devices and for remote maintenance. This PC is a Windows (registered trademark) type O
Software is built under S.

The image processing PC 11 is a personal computer dedicated to image processing. Information is exchanged with the main PC 10 by a serial communication method. Software is M
Built on S-DOS.

The image input board 15 is a board for inputting image data from the camera 16 to a memory on the image processing PC 12 by DMA transfer.

Up to two cameras can be connected, but only one camera is actually used for good / bad judgment, and the other is for monitor display.

The fiber sensor 17 and the trigger signal generating circuit 18 are optional parts connected to the camera, and are used when the control by the servo motor is incomplete due to slip of the feed roller 26 or the like.

The servo driver 19 is of a type that is connected to the main PC 10 by a dedicated bus. In this example, a dedicated bus called SSCNET20 is used.

The input / output board 21 is installed in the expansion slot of the main PC 10.

In addition to a normal input / output device consisting of a liquid crystal display 12, a keyboard 13 and a mouse 14, the operation section has a defective operation panel 23 including buttons and lamps connected to the input / output board 21. There is an LED indicator 24 for displaying what is detected.

The input / output device 22 is a cylinder for moving the feed roller 26 up and down, an actuator for operating the marking device, and a sensor for knowing the state of the machine.

FIG. 3 shows an overview of the operation panel in this inspection apparatus. FIG. 4 shows an outline of software of this inspection apparatus.

There are three operation modes of the present inspection apparatus: a production condition mode, a manual operation mode and an automatic operation mode.
The mode can be changed by pressing the button on the operation panel shown in FIG. However, it cannot be changed during automatic operation until it is stopped.

In the production condition mode, an inspection program is created, non-defective samples are taught, and operation parameters are set.

In the manual operation mode, the servo and rollers are manually operated. Specifically, by pressing a button on the operation panel in this mode, the following operation is possible.

Each time the roller pressing button 30 is pressed, the forward / backward state of the pressing cylinder is switched.

Each time the mark button 31 is pressed, the state in which the marking cylinder moves forward and backward is switched.

While the feed button 32 is being pressed, the servo motor moves in the positive direction. The speed can be selected from high speed, low speed, and constant length feed on the operation screen.

While the return button 39 is being pressed, the servo motor moves in the negative direction. The speed can be selected from high speed, low speed, and constant length feed on the operation screen.

In the automatic operation mode, automatic feeding operation and inspection are repeated. When the start button 33 is pressed, automatic operation is started. When the automatic operation is started, the next operation is repeatedly executed. First, there is a pitch feed operation by a servo motor. Secondly, there is an inspection by image processing at a low speed operation point of pitch feeding.

When the stop button 34 is pushed, the automatic operation is stopped.

The single button 35 is similar to the start button, but it operates only once and immediately stops automatically.

The retry button 36 does not move the servo motor and re-executes the inspection by the image only on the spot.

The home button 37 performs an origin return operation.

The reset button 38 is used to perform a releasing operation after an abnormality has occurred.

5 and 6 are conceptual diagrams of the pitch feed operation by the servo motor, which is the core of the automatic operation in this inspection apparatus, so as to be compared with the conventional method.

FIG. 5 shows a typical speed change during conventional automatic driving. Conventionally, a DC motor whose speed is controlled is used, and the speed is controlled by a signal from a sensor. When it is necessary to stop suddenly, such as when a defect is found, the brake is used to stop suddenly. Therefore, since the camera releases the shutter while moving at high speed, the exposure time becomes extremely short and an expensive strobe discharge tube is required to ensure accuracy.

For example, in the case of 3000 pieces per minute and a pitch of 10 mm, the speed is 500 mm / second, and if the accuracy of 0.01 mm is secured, the shutter speed is 1/5000.
A speed of 0 seconds is required.

FIG. 6 shows a typical speed change during automatic operation of the inspection apparatus.

The servo control can be controlled accurately by performing position feedback from the motor. In addition, acceleration and deceleration can be performed at high speed because the maximum torque of the servo motor can be effectively used.

In this inspection apparatus, stop or deceleration is repeated for each pitch of the product as shown in FIG. Although the figure shows the operation for complete stop, a method of decelerating without complete stop is also possible. To suppress vibration, do not stop completely,
In some cases, it is better to flow at a speed of about 10.

By variably controlling the speed in this way,
The exposure time can be extended, and good images can be obtained without using an expensive strobe discharge tube.

The acceleration / deceleration pattern adopts a motion such as a cycloid which causes less impact and reduces the load on the motor.

Considering the method of completely stopping, pitch 1
Maximum speed of 1000 mm / sec and maximum acceleration of 157 m when 3,000 cycloid acceleration / deceleration is performed at 0 mm / min.
Every second, every second (16G).

The rapid stop and return operation when a defect is found can be performed at high speed and accurately by servo control. This is because if the pitch is known, the specified pitch can be accurately returned by position control.
However, it is a condition that a large slip does not occur between the roller and the workpiece.

Although the cycloid is adopted in this example, other acceleration / deceleration patterns such as a spline curve may be adopted. In order to suppress the oscillation without stopping it completely, it is not possible to realize it with a pure cycloid, and thus it is necessary to use a piecewise function or a function defined as the sum of some functions.

Further, in order to deal with the case where such a complicated function is used, the method of referring to the function value table prepared in advance is effective for high speed processing. Although the cycloid is used in this embodiment, a method of referring to the function value table in the implementation stage is adopted for the purpose of speeding up. Of course, sequential calculation may be performed at the feed speed control execution stage as long as the processing is in time.

If there is no large slip between the roller and the work piece, the position of the work piece can be accurately determined by the servo encoder. Therefore, even if no special trigger sensor is used externally, the servo control section can generate an image pickup trigger. I can.

On the other hand, it is also possible to correct the feed deviation in real time by feeding back the target position in the image measurement result. That is, assuming that the pitch between products is constant, the amount of feed deviation can be calculated by calculating the difference between the position of the imaged object in the scheduled image and the position in the actually imaged image. It becomes possible to know.

[0065]

As described above, the feeding device of the present invention becomes slow at the timing when the object to be imaged is located near the center of the field of view of the image pickup device, and moves the object to be imaged to near the center of the field of view of the image pickup device. By making the target value of the feed speed variable so that the speed becomes high during the process, a large number of objects can be imaged per unit time and a good image for image processing can be obtained. You can

This contributes to the improvement of productivity in the sense that the inspection apparatus using image processing does not become a bottleneck in processing time and the capacity of the production line is not reduced.

At the same time, the present invention can be expected to increase the number of cases in which an image pickup device or an illuminating device for image processing that has relatively low performance can be adopted. Have.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a connector pin inspection device.

FIG. 2 is a schematic diagram of a control computer of the connector pin inspection device.

FIG. 3 is a schematic view of an operation panel in the connector pin inspection device.

FIG. 4 is a schematic diagram of software of a connector pin inspection device.

FIG. 5 is a typical speed change diagram during automatic operation of a conventional method.

FIG. 6 is a typical speed change diagram during automatic operation according to the present invention.

FIG. 7 is an external view of a connector pin.

[Explanation of symbols]

1 ... Connector pin processing device 2 ... Inlet side presser cylinder 3 ... Sensor tower 4 ... Exit side holding cylinder 5 ... Camera 6 ... Control device 7 ... Servo motor 8: Connector pin 9 ... slack part 10 ... Main PC 11 ... PC for image processing 12 ... Liquid crystal display 13 ... Keyboard 14 ... Mouse 15 ... Image input board 16 ... Camera 17 ... Fiber sensor ..Trigger generation circuit 19 ... Servo driver 20 ... SSCNET 21..I / O board 22 ... Input / output devices 23 ... Operation panel 24 ... LED display 25 .. Connector pin guide 26..Feed rollers 30 ... Roller foot button 31 ... Mark button 32 ... Send button 33 ... Start button 34 ... Stop button 35 ... Single button 36 ... Retry button 37 ... Home button 38 ... Reset button 39 ... Return button

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Claims (8)

[Claims] 1. A large number of image-capturing objects that are continuously conveyed as continuous materials are guided into the field of view of an image-capturing device to be passed therethrough, and image-capturing objects that pass one after another are intermittently imaged. In the method of feeding the imaged object using the imaged object feeding device, the speed becomes low at the timing when the imaged object is located near the center of the visual field of the imaging device, and in the process of moving the imaged object to the vicinity of the center of the visual field of the imaging device. By making the target value of the feed speed variable so that the speed becomes high,
An image pickup object feeding method capable of picking up a large number of objects per unit time and thereby obtaining a good image for image processing. 2. The method for feeding an imaged object according to claim 1, wherein a servomotor is used to move the imaged object and perform acceleration and deceleration for realizing a variable feed speed. 3. The shutter timing is determined without an external sensor when the position and speed of the object to be imaged can be controlled with sufficient accuracy.
Method of feeding the imaged object. 4. When the position and speed of the imaged object can be controlled with sufficient accuracy, the target position is fed back in the measurement result of the image to correct the feed deviation in real time. The image pickup object feeding method according to claim 1, 2, or 3. 5. A conveyance means including an imaging object supply source and a servo motor, a feed roller, a control computer, and the like for continuously conveying a large number of imaging objects that are continuously conveyed as continuous strips. A process of moving an imaging target to near the center of the field of view of the imaging device in the transportation device including the imaging device cooperating with these, at a timing when the imaging target is located near the center of the field of view of the imaging device. Then, by making the target value of the feed rate variable so that the speed becomes high, a large number of objects are imaged per unit time, and thus a good image for image processing can be obtained. An imaging object feeding device using the method of 1. 6. The method of claim 2 wherein a servomotor is used to move the object to be imaged and to accelerate and decelerate to achieve a variable feed rate. 5. The image pickup object feeding device of 5. 7. The method according to claim 3, wherein the shutter timing is determined without an external sensor when the position and speed of the object to be imaged can be controlled with sufficient accuracy. 6. The image pickup object feeding device of 6. 8. When the position and speed of the imaged object can be controlled with sufficient accuracy, the target position is fed back in the measurement result of the image to correct the feed deviation in real time. Claim 5 thru / or Claim 6 thru / or Claim 7 image pick-up object sending device using the method of Claim 4.