JP2000184355A - Image acquiring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire an image for every same recognizing object by deciding the timing where the recognizing object to be carried is photographed at different angles according to the position of the object, storing the acquired image groups in relation to the photographing time and collecting the image groups of the same object with difference of photographing times. SOLUTION: The products B which are carried on a conveyor C are detected by the sensors 21-23 and photographed after the illuminators 11-13, a timer and the shutters of TV camera 1-3 are actuated with the detection of products B defined as a trigger. The signals received from the cameras 1-3 are converted into the digital images by a quantizing device and also stored in a storage device as the data corresponding with the digital images and together with the time information acquired from the timer. Meanwhile, the image information are synthesized and stored in the storage device. The image groups can be collected for every same object despite the irregular supply intervals of products B as long as these products are carried at an almost constant speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image for capturing an image of a product from various angles using a plurality of television cameras, combining the plurality of images into one, and performing inspection by image processing. It relates to an acquisition device.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for imaging an object using an imaging apparatus, a sensor and a timer, Japanese Patent Application Laid-Open No. 9-29
No. 8740, there is an image determination device. However, in this conventional example, it is possible to use a single TV camera to store the time at which the sensor of an object sequentially entering the sensor is applied to the sensor together with the video, but using a plurality of TV cameras, Moreover, it has not been possible to associate and record the same object.

[0003]

For example, when an object to be inspected is imaged from all around while being moved by a conveyor such as a conveyor or the like, illumination is applied from multiple directions at the time of imaging, so that it is impossible to image the entire circumference at the same time. . Also, due to the physical size of the TV camera, the TV camera may not be able to be arranged, for example, by using a plurality of lighting devices and a plurality of TV cameras, shifting the imaging position of each TV camera, A plurality of images are taken so that the illumination by the illumination device does not affect each other. For this reason, a sensor is provided at each imaging position, the lighting device is activated at the moment when the product reaches a position suitable for imaging, the shutter of the television camera is simultaneously released, and a plurality of captured images are output for each same product. When the sensor does not operate properly and the image that should be taken cannot be obtained, or when the sensor malfunctions, an unnecessary image is taken. Occurs even once, there is a problem that the imaging result of the same product is shifted.

[0004] Further, if the time interval at which the product is put in is not constant, a more complicated synthesizing process is required because images cannot be taken at a constant interval. For this reason,
If images are combined in the order in which the images were taken by the television cameras, images of different products may be combined incorrectly.

[0005] Further, if the image acquisition processing is performed by individually controlling the image pickup timing of a plurality of television cameras by an image acquisition device having one CPU, the control becomes complicated when the number of television cameras increases. This causes a problem that the processing speed is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and images of a product moving on a transport device are taken by a plurality of television cameras from various angles. Both propose an apparatus that can acquire an image for each same product.

[0007]

In order to achieve the above-mentioned object, an image acquisition apparatus according to the present invention comprises a plurality of imaging devices for imaging a recognition target conveyed at a substantially constant speed from a plurality of different angles. Means, means for determining the imaging timing of each imaging means according to the position of the recognition target, timekeeping means for acquiring the imaging time of each imaging means, and a group of images obtained from each imaging means It is characterized in that it comprises means for storing in association with each other, and means for collecting a group of images of the same recognition target with a time difference between the imaging times.

[0008]

(Embodiment 1) FIG. 1 is a diagram showing an embodiment of an image acquiring apparatus according to the present invention. In the figure, 1 to 3 are television cameras, 11 to 13 are lighting devices, and 21 to 23 are sensors. The cylindrical product B is an inspection object, and a plurality of inspection objects are transported by a conveyor C in a direction indicated by an arrow. Although the interval between each test object is not constant,
The transport speed of the conveyor C is substantially constant.

While the inspection object is being conveyed by the conveyor, the inspection object is detected by the passage sensors 21 to 23, and using this as a trigger, the illumination devices 11 to 13, the timer, and the shutters of the television cameras 1 to 3 are operated to take an image. I do. The signals from the television cameras 1 to 3 are converted into digital images by a quantization device and stored in a storage device. At the same time, the time information obtained by the timer is stored in the storage device as data associated with the digital image. Further, the image stored in the storage device is subjected to the combining process described in each of the following embodiments, and is stored in the storage device as a combined image.

When the passage of the product B is detected by the sensor 21, the time information of the timer (t = t 1) is stored as the imaging time information of the television camera 1. next,
When the passage of the same product B is detected by the sensor 22, the timer time information (t = t2) is stored as the imaging time information by the television camera 2. Assuming that the conveying speed of the conveyor C is V and the installation interval between the sensors 21 and 22 is L12,
After the same product B passes through the sensor 21, the next sensor 22
Is a time interval until passing through t2-t1 = L12 / V
Becomes Next, when the product B moves further and the passage of the same product B is detected by the sensor 23, the time information (t = t3) of the timer is stored as the imaging time information by the television camera 3. Assuming that the conveying speed of the conveyor C is V and the installation interval between the sensors 22 and 23 is L23, the time interval from when the same product B passes through the sensor 22 to when it passes through the next sensor 23 is t3-t2 = L23 / V.

[0011] Then, those whose time intervals are constant are collected to determine that they are the image group of the same product. That is, in the inspection apparatus for inspecting the product B from an image captured by using a plurality of the television cameras 1, 2, and 3, in a configuration in which the time interval for introducing the product B is not constant, The imaging times t1, t2, and t3 are recorded, and those having a constant time interval t2-t1, t3-t2 are collected to determine that the images belong to the same product. The time intervals t2-t1 and t3-t2 are recorded when the first product passes. Alternatively, the speed V of the conveyor C and the installation intervals L12, L of the sensors 21, 22, 23 are determined in advance.
Calculated from 23.

The following conditional expression 1 is a conditional expression used to identify the same product in a configuration of three television cameras. (Unless otherwise specified, the number of TV cameras is 3
And Conditional expression 1: (t2−t1) −Δt ≦ P12 ≦ (t2−t1) + Δt and (t3−t2) −Δt ≦ P23 ≦ (t3−t2) + Δt

Where t1, t2, and t3 are the imaging times of the television cameras 1, 2, and 3, P12 and P23 are parameters indicating the difference between the imaging times between the television cameras 1-2 and 2-3, Δt is an error allowable value for determining the same product.

(Second Embodiment) In the first embodiment, the difference between the imaging time interval parameter and the time data gradually increases due to the temporal error of the timer of each of the television cameras 1, 2, and 3. Assuming that the errors of the timers of the television cameras 1 and 2 when one hour has elapsed are + T1 and -T2, respectively, it becomes 10 × (T1 + T2) after 10 hours have elapsed. Therefore, each time the same product is identified, the difference of the time data obtained at this time is reset as an imaging time interval parameter, thereby solving the problem of a temporal error. In the above example, every time conditional expression 1 is satisfied, (t2-t1) is input to P12, and (t3-t2) is input to P23.
Enter As described above, by resetting the imaging time interval parameters P12 and P23 at each photographing,
It is possible to correct a temporal error of a timer attached to each of the television cameras 1, 2, and 3. Conveyor C
Can be handled even when the speed of the vehicle fluctuates.

(Embodiment 3) In Embodiment 1 described above, the accuracy of the sensor of each TV camera and the accuracy of the timer are determined by
The value of the imaging time interval varies. Therefore, a difference between time data obtained each time the product is identified as the same product is stored a plurality of times as an imaging time interval parameter, an average value of the values is calculated, and the imaging time interval parameter P is calculated using the average value.
By resetting 12, P23, the problem of time accuracy can be solved. Suppose that N is an integer of 2 or more, and the i-th time interval parameter from the newest one at the time of imaging at a normal imaging interval is P (i) 1
2, P (i) 23, P12 = ＮP (i) 12 / N P23 = ΣP (i) 23 / N

(Embodiment 4) FIG. 2 is an explanatory view of Embodiment 4 of the present invention. In this embodiment, when production is temporarily stopped,
If there is no sensor input for a relatively long time, for example, if production has stopped and 10 minutes or more have elapsed, the imaging time interval parameters P12 and P23 are discarded. Next, the time when the first product passes when the production is resumed is measured, and is newly set as imaging time interval parameters P12 and P23. In the figure, the products shown in gray are the products that were initially introduced when the production was resumed. This product is a TV camera 1, 2,
The timing at which the image was detected and detected by the sensor 3
= T1, t2, t3, P12 = t2-t1, P
23 = t3-t2. This can solve the problem of a temporal error of the timer when the production is temporarily stopped. Further, it is possible to cope with the case where the speed of the conveyor C after the restart of the production is different from the previous speed.

(Embodiment 5) FIG. 3 is an explanatory view of Embodiment 5 of the present invention. Images picked up by the television cameras 1 to 3 are judged as non-defective / defective using an inspection device by image processing. As a result of this determination, the product determined to be defective must be discharged by the discharge device E. However, if the discharge signal is not accurately controlled, the discharge cannot be performed or another product is discharged. Occurs. Therefore,
When the time from the imaging time (t = t3) to the discharge of the television camera 3 is T, the timer controlled by the sensor 23 is used for controlling the activation timing of the discharge device. That is, the imaging time (t = t3) indicated by the timer when imaging the product (product shown in gray in the figure) determined to be defective by the inspection device is transferred to the discharge device,
The discharge device E determines the time at which the product should come to the predetermined position (t = t
3 + T), and then the discharging operation is started to discharge the product.

(Embodiment 6) FIG. 4 is an explanatory view of Embodiment 6 of the present invention. Images taken by the television cameras 1, 2, and 3 are transferred to an image memory and temporarily stored in a memory unit for short-term storage, and are also transferred to an image processing device and inspected by image processing. . Test results,
If the product imaged at the timing of t = t1, t2, t3 is determined to be defective, information on the imaging time is given to the memory unit as an image storage signal. The memory unit searches for an image at a timing: t = tx (x = 1, 2, 3, 3) corresponding to the image storage signal given from the image processing device, and thereby, among the image group stored in the memory unit for a short time, Only the image of the product shown in gray in the figure is extracted and stored in a magnetic storage device such as a hard disk.

For example, it is desirable that only defective product images be stored for a long period of time in order to study later process improvements. However, although a storage device generally called a memory is high-speed, it has disadvantages such as erasure of storage without power supply and relatively small storage capacity. Further, a device generally called a magnetic storage device has features such as semi-permanent storage and a large capacity, but has a drawback of a low writing speed. Therefore, only the defective product image data from among the image data stored in the memory at the inspection stage is transferred to a magnetic storage device such as a hard disk. At the time of imaging, the stored time parameters are specific to the image data, so when transferring data from the memory to the hard disk, search for image data that matches the time parameters from the memory and transfer the data to the hard disk. I do.

(Embodiment 7) FIG. 5 is an explanatory view of Embodiment 7 of the present invention. The present embodiment is characterized in that a plurality of television cameras are simultaneously controlled by a trigger generated when a sensor detects the passage of a product, and images are taken from a plurality of directions at the same timing. For example,
When the side surface and the top surface of the product are imaged simultaneously and the side image and the top image are inspected by different image processing, the shutters of the side and top television cameras are controlled based on the trigger signal from the sensor, and the images are taken simultaneously. In the illustrated example, first, a trigger generated by one sensor causes
The side camera 1a and the top camera 1b are simultaneously controlled, and the product is imaged at the same timing from the side and top directions. Next, the side camera 2a and the top camera 2b are simultaneously controlled by the trigger generated by another sensor, and the same product is imaged from different angles at the same timing from different directions. Side cameras 1a and 2a
Are combined as an image of the side camera and inspected by image processing. Also, the top camera 1b
And 2b are combined as an image from the top camera and inspected by another image processing.

(Eighth Embodiment) FIG. 6 is an explanatory diagram of an eighth embodiment of the present invention. The present embodiment is characterized in that a steady displacement amount (parallel movement, enlargement / reduction, rotation, etc.) at the time of imaging is corrected by means such as normalization with respect to an image of a television camera for imaging a product. . Multiple TV cameras for imaging products are positioned in the field of view, magnification, rotation (tilt)
It is ideal to keep such conditions as constant, but in reality, the position of the television camera cannot be perfectly adjusted, so that a steady shift occurs in the obtained image. Therefore, after performing correction calculation on the obtained image, the image is stored in the storage device. In the illustrated example, when the adjacent television cameras 1 and 2 are capturing images that are constantly translated in parallel, one or both of the data transferred from the television cameras 1 and 2 are translated. And then store it in the storage device.

(Embodiment 9) FIG. 7 is an explanatory view of Embodiment 9 of the present invention. In the present embodiment, a virtual development view is created on the image memory by copying image data as necessary in consideration of the positional relationship of imaging by the TV camera, and a wider and more accurate inspection is performed. is there. In the figure, numerals 1 to 3 indicate the fields of view of the respective television cameras (three in this example). By copying the field of view of the TV camera 1 on the image memory,
Inspection on the boundary between the television camera 3 and the television camera 1 is also possible.

FIG. 8 is a top view of a product to be inspected according to this embodiment. In the example shown in the figure, three images obtained by imaging the entire circumference of a cylindrical product from three different angles with three television cameras are combined to inspect for defects. If there is a defect between 1 and the field of view of the TV camera 3, the image of the defect is divided,
The accuracy of defect detection by an inspection device using image processing at a later stage is reduced. Then, based on the geometrical positional relationship, the image of the television camera 1 is written twice in the image memory as shown in FIG. By doing so, it is possible to continuously process images at the boundary between the television camera 3 and the television camera 1.

[0024]

According to the first aspect of the present invention, an image group of the same recognition target is collected from a group of images taken at a plurality of different angles at a plurality of timings by a plurality of imaging means with a time difference of the imaging time. Therefore, if the sheet is conveyed at a substantially constant speed, an image group can be collected for each of the same recognition targets even if the intervals at which the images are input are irregular. According to the second to fourth aspects of the present invention, by updating the information on the time difference between the imaging times as needed, it is possible to eliminate the time-dependent error of the timekeeping means, and to cope with fluctuations in the transport speed.

According to the fifth aspect of the present invention, the discharge timing of the discharge device for discharging the recognition target determined as a defective product from the transport path is calculated based on the information of the imaging time. Can be easily controlled. According to the sixth aspect of the present invention, since the secondary storage device for storing the collected image group of the same recognition target is provided, for example, only the defective product image can be stored for a long time in order to study later process improvement. It becomes possible to save.

According to the seventh aspect of the present invention, a plurality of image pickup means are operated at the same image pickup timing corresponding to one position of the object to be recognized, so that the image of the object to be recognized is simultaneously picked up from a plurality of different angles. The number of sensors for detecting the position of the recognition target can be reduced. According to the eighth aspect of the present invention, since there is provided a means for correcting a shift amount between the image pickup means for an image group obtained from a plurality of image pickup means, the positioning accuracy of the image pickup means may be low, and Adjustment work becomes easier. According to the ninth aspect of the present invention, it is possible to continuously process the image of the boundary portion of the visual field of the imaging unit, so that it is possible to prevent the defect detection accuracy from being deteriorated depending on the location where the defect exists.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of an image acquisition device of the present invention.

FIG. 2 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 3 is an explanatory diagram of Embodiment 5 of the present invention.

FIG. 4 is an explanatory diagram of a sixth embodiment of the present invention.

FIG. 5 is an explanatory diagram of a seventh embodiment of the present invention.

FIG. 6 is an explanatory diagram of an eighth embodiment of the present invention.

FIG. 7 is an explanatory diagram of Embodiment 9 of the present invention.

FIG. 8 is a plan view of a product imaged according to Embodiment 9 of the present invention as viewed from above.

[Explanation of symbols]

 1, 2, 3 TV camera 11, 12, 13 Lighting device 21, 22, 23 Sensor C Conveyor B Product

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koshi Akado 1048 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works F-term (reference) 5C054 AA01 AA05 CA04 CC03 CH02 EA01 EA05 FC11 FD00 GA01 GB01 HA01 HA05

Claims (9)

[Claims] A plurality of image pickup means for picking up an image of a recognition target conveyed at a substantially constant speed from a plurality of different angles; a means for determining an image pickup timing of each image pickup means in accordance with a position of the recognition target; A timer for acquiring an imaging time of the means, a means for storing an image group obtained from each imaging means in association with the imaging time, and a means for collecting an image group of the same recognition target with a time difference between the imaging times. An image acquisition apparatus comprising: 2. The image acquisition apparatus according to claim 1, further comprising means for updating information on a time difference between imaging times each time an image group of the same recognition target is normally collected. 3. A means for recording information on a time difference between imaging times each time a group of images of the same recognition target is normally collected, and averaging the information on the time difference between the imaging times for the latest plurality of times. 3. The image acquisition apparatus according to claim 2, further comprising a unit configured to set the calculated value as information on a time difference between imaging times. 4. If the recognition target is not detected for a certain period of time or more, the information on the time difference between the imaging times is discarded, and the information on the time difference between the imaging times is reset based on the imaging time measured for the next product put in. 3. The image acquisition device according to claim 2, further comprising: 5. A determination device for processing a group of images collected for the same recognition target to determine a defective product, a discharge device for discharging the recognition target determined to be a defective product from a transport path, and a discharge device. 2. The image acquisition apparatus according to claim 1, further comprising: means for calculating the timing of discharging the defective product by the apparatus based on information on the imaging time stored in association with the image group of the defective product. 6. A secondary storage device for storing an image group for a specific recognition target among the same recognition target images collected based on the time difference between the imaging times. The image acquisition device according to claim 1. 7. A means for determining an imaging timing of each imaging means in accordance with a position of a recognition target includes operating a plurality of imaging means at the same imaging timing in correspondence with one position of the recognition target to generate a plurality of different angles. 2. The image acquisition device according to claim 1, wherein a recognition target is imaged simultaneously from the object. 8. The image acquisition apparatus according to claim 1, further comprising: a unit that corrects a shift amount between the image pickup units for an image group obtained from the plurality of image pickup units. 9. The image processing apparatus according to claim 1, further comprising: a unit configured to store an image group of the same recognition target captured from a plurality of different angles as an image developed based on a geometric positional relationship of the recognition target. Item 2. The image acquisition device according to Item 1.