JP2014108868A - Transfer device and box packing system including transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer device capable of accurately detecting a state of a workpiece and particularly detecting a position and a state of each workpiece in short time if a plurality of workpieces are present within a field of view of imaging means.SOLUTION: A transfer device picks up a reflected illumination image after picking up a transmitted illumination image of a workpiece (W), detects a position of the workpiece (W) on the basis of the transmitted illumination image, and limits a power matching target range of the reflected illumination image on the basis of the detected position of the workpiece (W), conducts the pattern matching within the limited range, detects a state of the workpiece (W) on the basis of a result of the pattern matching, and transfers the workpiece (W) in accordance with the detected position and state of the workpiece (W).

Description

  The present invention relates to a transfer device for transferring a workpiece, in particular, a workpiece in which a partial deformation different for each individual such as a bag is transferred, and a boxing system provided with the transfer device.

  In general, a transfer device that detects the position of a workpiece and transfers the workpiece based on the detected position images the workpiece by an imaging means such as a CCD camera, and performs predetermined image processing on the captured image. The position of is detected. Conventionally, there are a transmission illumination method and a reflection illumination method for position detection based on this image.

  The transmitted illumination method is a method of irradiating the work with light from the back and observing the transmitted light and silhouette of the work. Since this method can capture the outline of a workpiece as a silhouette, it can detect the exact position of the workpiece, and when the color of the surface of the workpiece is similar to the color of the mounting surface on which the workpiece is placed Is also excellent in that it can be applied.

  However, since this method cannot detect the pattern on the surface of the workpiece, there is a problem that a workpiece whose direction is 180 degrees, a workpiece whose front and back are reversed, a workpiece whose symbol is different for each product type, and the like cannot be distinguished from each other. Patent Document 1 discloses a technique for inspecting a chip of a tablet or the like by using a transmission illumination unit.

  The reflective illumination method is a method in which light is irradiated onto the work from above and the reflected light from the surface of the work is observed. This method is superior in that it can detect a pattern on the surface of a workpiece, and thus can distinguish a workpiece having a different orientation by 180 degrees, a workpiece having opposite sides, a workpiece having a different pattern for each type, and the like.

  However, when the work is a bag work in which the contents of food, etc., that vary in size, shape, orientation, etc. are enclosed in a packaging bag, each bag has bulges, dents, wrinkles, etc. Different partial deformations occur from individual to individual. Even if the pattern printed in advance on the surface of the bag is the same, if the workpiece is imaged in this manner, the surface pattern is distorted in accordance with the deformation of the workpiece, so that a partially different image is captured for each workpiece.

  Here, in order to detect a characteristic pattern of the workpiece from the captured image, image processing called pattern matching is generally used. That is, the reference image is moved in the X and Y directions on the target image, and a position where the similarity with the reference image is maximized is searched. If the maximum value of the similarity is equal to or greater than a predetermined threshold, the image at this position is It is determined that it matches the reference image. If it is smaller than the threshold value, it is determined that there is no image that matches the reference image.

  Even when the pattern is distorted as described above, it is necessary to set this threshold to a certain level in order to detect a characteristic pattern of the workpiece, but if this threshold is too low, it differs from the reference image. It is erroneously determined that the images also match. Therefore, in this reflective illumination method, there is a problem that it is difficult to accurately detect the direction of the workpiece, the front and back, the type of the product, etc. in the case of a workpiece such as a bag.

  In order to take advantage of both of these advantages, for example, as disclosed in Patent Document 2, a method using both images captured by transmitted illumination and reflected illumination is conceivable. However, even with this method, for example, when there are a plurality of workpieces in the field of view of the imaging means, there is a problem that it takes a long time to detect a characteristic pattern of each workpiece from the reflected illumination image.

Japanese Patent Application Laid-Open No. 2012-127827 JP 2010-131178 A

  Therefore, the present invention accurately detects the state of a workpiece in which a partial deformation that differs for each individual such as a bag is detected, and particularly when there are a plurality of workpieces in one image, the position and state of each workpiece are determined. The problem is to detect in a short time.

  In order to solve the above problems, the transfer apparatus according to the present invention is configured as follows.

First, the invention according to claim 1 of the present application is
A transfer apparatus comprising an image pickup means for picking up an image of one or a plurality of works, and a transfer means for holding and moving the work, wherein the transfer apparatus comprises:
Reflected illumination means provided at a position where reflected light from the surface of the workpiece is incident on the imaging means;
Transmitted illumination means provided across the workpiece on the line of sight of the imaging means;
Control means for capturing a reflected illumination image of the workpiece illuminated by the reflective illumination means after the image capturing means captures a transmitted illumination image of the workpiece illuminated by the transmitted illumination means;
The control means includes
A position detection unit that detects the position of the workpiece based on the contour of the workpiece extracted by processing the signal of the transmitted illumination image;
Of the reflected illumination image, a target range limiting unit that limits a target range of pattern matching performed later to a predetermined range based on the detected position;
A pattern matching processing unit that performs the pattern matching with a reference image for the limited target range;
A state detector that detects the state of the workpiece based on the result of the pattern matching;
A transfer control unit for transferring the workpiece by controlling the transfer means according to the detected position and the state;
A transfer apparatus comprising:

  According to the present invention, after capturing a transmitted illumination image, the reflected illumination image is captured, and based on the position of the workpiece detected from the transmitted illumination image, a target to be subjected to pattern matching with the reference image. Since the range is limited and pattern matching is performed for the limited target range, the workpiece state can be accurately detected, and particularly when there are multiple workpieces within the field of view of the imaging means, the position and state of the workpiece Can be detected in a short time.

The invention according to claim 2 of the present application is the invention according to claim 1,
The state detection unit detects at least one of the orientation, front and back, and type of the workpiece as the workpiece state.

  According to the present invention, it is possible to accurately detect the workpiece direction, front / back, or product type as the state of the workpiece, and particularly when there are a plurality of workpieces within the field of view of the imaging means, the workpiece orientation, front / back, and the workpiece position. Or a variety can be detected in a short time.

Furthermore, the invention according to claim 3 of the present application is the invention according to any one of claims 1 and 2,
Comprising the transfer device;
A boxing system, wherein the workpiece is stored in a box by the transfer device.

  According to the present invention, the orientation of the workpiece, the front / back surface, the type of the product, etc. are detected, and the transfer device is transported and controlled according to the detected state. And can be stored in a box.

  In the transfer apparatus according to the present invention, after capturing the transmitted illumination image, the reflected illumination image is captured, and based on the position of the workpiece detected from the transmitted illumination image, pattern matching with the reference image of the reflected illumination image is performed. Since the target range is limited and pattern matching is performed for the limited target range, it is possible to accurately detect the state of the workpiece, and particularly when there are a plurality of workpieces in one image, the position and state of the workpiece Can be detected in a short time.

It is a schematic side view which shows the whole structure of the transfer apparatus which concerns on one Embodiment of this invention, and the boxing system provided with this transfer apparatus. It is a block diagram of the controller of the transfer apparatus of FIG. It is a flowchart which shows operation | movement of the transfer apparatus of FIG. It is a schematic side view which shows the imaging (FIG. 4 (a)) of a transmission illumination image, and the imaging (FIG.4 (b)) of a reflected illumination image by the transfer apparatus of FIG. It is a figure which shows the transmitted illumination image (FIG. 5 (a)) and reflected illumination image (FIG.5 (b)) in case the two workpiece | work exists in the visual field of a camera imaged by the transfer apparatus of FIG.

  Hereinafter, embodiments of a transfer device according to the present invention and a boxing system including the transfer device will be described with reference to the drawings.

(1) Whole structure of boxing system As shown in FIG. 1, the boxing system 1 is provided with the transfer apparatus 10 and the belt conveyor 20 as main structures.

  The boxing system 1 is a system for, for example, packing and shipping a plurality of workpieces W, which are bag items in which contents such as foods with variations in size, shape, orientation, etc. are enclosed in a packaging bag, From the bag packaging station on the side, it is transported on the belt conveyor 20 via an inspection position P1 described later to a downstream boxing station where an extraction position P2 described later is present. In the boxing station, the transferred work W is stored by the transfer device 10 in an aligned state in a box B such as a cardboard box.

(2) Overall Configuration of Transfer Device As shown in FIG. 1, a transfer device 10 according to the present invention includes a robot 11, a CCD camera 12, a reflected illumination light source 13, a transmitted illumination light source 14, as main components. A controller 15 is provided.

  The CCD camera 12, the reflected illumination light source 13, and the transmitted illumination light source 14 are provided at an inspection position P <b> 1 in the middle of the belt conveyor 20. The robot 11 is provided in the vicinity of the take-out position P2 on the downstream side of the inspection position P1. Hereinafter, each component of the transfer apparatus 10 will be described in detail.

(2-1) Robot As shown in FIG. 1, the robot 11 is a ceiling-suspended multi-joint robot. The robot 11 transfers the workpiece W conveyed by the belt conveyor 20 from the take-out position P2 on the belt conveyor 20 into the box B, and stores the workpiece W in an aligned state.

  The robot 11 may be an articulated robot having a necessary degree of freedom and a portable weight in consideration of a desired storage state of the workpiece W in the box B, the mass of the workpiece W, and the like. As the type of the articulated robot, a parallel link type, a vertical articulated type, or the like may be used.

(2-2) CCD Camera The CCD camera 12 is a general industrial camera that uses a CCD element as a light receiving element, and is capable of imaging a work W as a subject in color and on the belt conveyor 20. A field of view and resolution of a necessary size are provided so that the workpiece W that is placed and conveyed can be imaged. In addition, the CCD camera 12 is controlled by the imaging control unit 103 so that the workpiece W illuminated by any one of the light source for reflection illumination 13 and the light source for transmission illumination 14 described later can be imaged.

(2-3) Light source for reflected illumination The light source for reflected illumination 13 is so-called oblique illumination (dark field illumination) in which light is obliquely applied to a work W that is a subject. For example, ring illumination, line illumination, fiber Light sources having various light emitting surface shapes such as illumination can be used. The reflected illumination light source 13 is controlled by the illumination control unit 104 so as to be turned on / off at a desired timing.

  The reflected illumination light source 13 is not limited to oblique illumination, and a half mirror is inserted between the CCD camera 12 and the work W, and the light from the light source is reflected by the half mirror, Coaxial epi-illumination that irradiates the workpiece W with light from the same direction may be used.

(2-4) Light source for transmitted illumination The light source for transmitted illumination 14 is a so-called backlight, and is a surface illumination using an LED and a diffusion plate. Light is irradiated in parallel from the lower surface of the work W, which is the subject, via the belt conveyor 20. The transmitted illumination light source 14 is controlled by the illumination control unit 104 to be turned on / off at a desired timing.

(2-5) Controller As shown in FIG. 2, the controller 15 includes a storage unit 101 such as a RAM and a ROM, an information processing unit 102 such as a CPU, an imaging control unit 103 that controls the CCD camera 12, and reflected illumination. An illumination control unit 104 that controls the light source 13 and the transmitted illumination light source 14 and a robot control unit 105 that controls the robot 11 are mainly configured.

(2-5-1) Storage Unit The storage unit 101 stores transmission illumination image data 111 and reflection illumination image data 112 output from the CCD camera 12 to the controller 15 and stores them in a pattern matching processing unit 123 described later. The reference image data 113 to be used is stored in advance.

(2-5-1) Information Processing Unit The information processing unit 102 mainly includes a position detection unit 121, a target range limitation unit 122, a pattern matching processing unit 123, and a state detection unit 124. The information processing unit 102 can read image data 111, 112, 113 stored in the storage unit 101, various setting information input by the operator to the storage unit 101 from an external input unit (not shown), and the like.

(2-5-1-1) Position Detection Unit The position detection unit 121 reads the transmitted illumination image data 111 of the workpiece W from the storage unit 101 and detects the position of the workpiece W, for example, the position of the area center of gravity G.

(2-5-1-2) Target Range Limiting Unit The target range limiting unit 122 reads the reflected illumination image data 112 from the storage unit 101, and reflects based on the position of the workpiece W detected by the position detection unit 121. A part of the illumination image is limited as a target range for performing pattern matching described later. In addition, when there are a plurality of workpieces W within the field of view of the CCD camera 12, the target range is limited for each workpiece W.

(2-5-1-3) Pattern Matching Processing Unit The pattern matching processing unit 123 reads the reference image data 113 registered in advance from the storage unit 101 and is limited by the target range limiting unit 122 in the reflected illumination image. Pattern matching is performed only for the target range.

  If there are a plurality of workpieces W in the field of view of the CCD camera 12 and the target range limiting unit 122 limits a plurality of target ranges, pattern matching is performed for each target range. In addition, in order to detect each of a plurality of types of workpieces W, reference image data 113 of each type of workpiece W is registered in the storage unit 101 in advance, and each reference image data 113 is sequentially read out from the storage unit 101 to perform pattern matching. May be repeated.

  Since the pattern matching executed by the pattern matching processing unit 123 is a known image processing technique, it will be briefly described below. First, the reference image is rotated, horizontally, and vertically moved by a predetermined step size on the image to be subjected to pattern matching, and the similarity to the reference image at each position and angle is calculated. Next, a position and an angle at which the degree of similarity is maximized are searched. If the maximum value of the degree of similarity is equal to or greater than a predetermined threshold, it is determined that the image at the position and angle matches the reference image. If it is smaller, it is determined that there is no image that matches the reference image.

  Actually, the reference image is horizontally / vertically moved at a predetermined step size, the similarity is calculated for each position, the reference image is further rotated by the step size, and again after the rotational movement. By moving the reference image horizontally and vertically at each step size and calculating the similarity for each position, the similarity for all the combinations of positions and angles is calculated.

(2-5-1-4) State Detection Unit The state detection unit 124 detects the state of the workpiece W such as the orientation, front / back, and product type based on the result of the pattern matching processing unit 123. That is, when it is determined that the reference image F matches, the direction of the workpiece W is detected based on the angle of the matched image. If it is determined that there is no image that matches the reference image F, it is determined that the front and back of the workpiece W are reversed or that the workpiece W is of a different type.

(2-5-2) Imaging Control Unit The imaging control unit 103 controls the CCD camera 12 in conjunction with an illumination control unit 104 (to be described later) when capturing an image for transmitted illumination and an image for reflected illumination. That is, at the time of imaging of the transmitted illumination image, the imaging controller 103 is turned on by turning on the transmitted illumination light source 14 and turned off the reflected illumination light source 13 by the illumination controller 104 and illuminates the workpiece W only with the transmitted illumination. Thus, the CCD camera 12 is controlled to image the workpiece W. Further, at the time of capturing an image for reflected illumination, the imaging control unit 103 turns on the reflected illumination light source 13 and turns off the transmitted illumination light source 14 by the illumination control unit 104 and illuminates the workpiece W only with the reflected illumination. Thus, the CCD camera 12 is controlled to image the workpiece W.

(2-5-3) Illumination control unit The illumination control unit 104 operates in conjunction with the imaging control unit 103 as described above when capturing a transmission illumination image and a reflection illumination image, and reflects light sources for reflection illumination during imaging. The reflective illumination light source 13 and the transmitted illumination light source 14 are controlled to be turned on / off so that only one of the light source 13 and the transmitted illumination light source 14 is turned on.

(2-5-4) Robot Control Unit The robot control unit 105 controls the conveyance of the robot 11 based on the state of the workpiece W detected by the state detection unit 124, the front and back, the product type, and the like. Specifically, in order to align the direction of the plurality of workpieces W, the robot 11 changes the direction on the horizontal plane while conveying the workpieces W. Further, in order to align the front and back of the work W, the front and back are reversed while the work W is conveyed by the robot 11. Furthermore, in order to arrange the types of workpieces W, the robot 11 sorts the workpieces W for each type.

(3) Belt conveyor The belt conveyor 20 is a conveyor that places a plurality of workpieces W on an endless belt and conveys them continuously or intermittently. The endless belt transmits light from the above-described light source for transmitted illumination 14. Made of possible materials. Further, in the case of the present embodiment, the width of the endless belt is such a dimension that a plurality of workpieces W can be arranged on the belt in the widthwise direction at intervals.

  Instead of the belt conveyor 20, a roller conveyor, a floating conveyor, or the like may be used as long as light can pass through the workpiece W. Further, a guide member for roughly aligning the direction of the workpiece W to be conveyed and the position in the width direction may be provided in the middle of the belt conveyor 20.

(4) Operation of Transfer Device and Box Packing System Provided with Transfer Device The operation of the transfer device 10 will be described with reference to FIGS. 5A and 5B respectively show a transmitted illumination image and a reflected illumination image when two works W1 and W2 are simultaneously imaged in the field of view of the CCD camera 12. FIG.

  In step S <b> 1, as illustrated in FIG. 4A, the imaging control unit 103 and the illumination control unit 104 capture an image of the outline of the work W illuminated by the transmitted illumination light source 14 using the CCD camera 12. At this time, as shown in FIG. 5A, the transmitted illumination image captured by the transmitted illumination is irradiated with light from the back surface of the workpieces W1 and W2, so that the surfaces of the workpieces W1 and W2 that are subjects are dark. The belt conveyor 20 around it appears bright because light is transmitted therethrough. A binarized version of this transmitted illumination image is stored in the storage unit 101 as transmitted illumination image data 111.

  In step S <b> 2, the position detection unit 121 detects the position of the workpiece W in the field of view of the CCD camera 12 based on the obtained transmitted illumination image data 111. The + mark shown in FIG. 5A indicates the area centroids G1 and G2 of the workpieces W1 and W2.

  In step S <b> 3, as shown in FIG. 4B, the CCD camera 12 captures an image of the surface of the workpiece W illuminated by the reflected illumination light source 13. In the reflected illumination image captured at this time, as shown in FIG. 5B, the surface symbols of the workpieces W1 and W2 are reflected. Further, the reflected illumination image data 112 is stored in the storage unit 101 from the CCD camera 12.

  In step S4, as shown in FIG. 5B, the target range limiting unit 122 sets a predetermined range from the positions G1 and G2 of the workpieces W1 and W2 detected in step S2 in the reflected illumination image. W2 is limited to target ranges A1 and A2 for which pattern matching is performed.

  In step S5, the reference image data 113 stored in advance in the storage unit 101 is read from the storage unit 101, and in the pattern matching processing unit 123, only the workpieces W1 and W2 for the target ranges A1 and A2 limited in step S4. Perform pattern matching for. Note that the image shown in the lower right of FIG.

  In step S6, based on the result of pattern matching in step S5, the state detection unit 124 detects the state (direction, front and back, product type, etc.) of each workpiece W1, W2. According to the example shown in FIG. 5B, the directions of the workpieces W1 and W2 are different from each other by 180 degrees, but both the workpieces W1 and W2 are detected to have the same type with the surface facing up.

  In step S <b> 7, the robot controller 105 controls the conveyance of the robot 11 according to the detected state of the workpiece W. For example, as shown in FIG. 5B, when the orientations of the workpieces W1 and W2 are different from each other by 180 degrees, the orientation of one workpiece W2 is rotated by 180 degrees on the horizontal plane so as to match the other workpiece W1. By transferring, the workpieces W1 and W2 can be stored in the box B as the transfer destination in an aligned state.

(5) Characteristics of the transfer device and the packaging system including the transfer device According to the transfer device 10, after the transmission illumination image is captured, the reflected illumination image is captured and detected from the transmission illumination image. Based on the position of the workpiece W, the target range A for pattern matching with the reference image F in the reflected illumination image is limited, and pattern matching is performed for the limited target range A. Can be detected. In particular, when there are a plurality of workpieces W1 and W2 in the field of view of the CCD camera 12, the positions and states of the workpieces W1 and W2 can be detected in a short time.

  In addition, according to the present transfer apparatus 10, the orientation, front, back, and type of the workpiece W can be accurately detected as the state of the workpiece W. In particular, when there are a plurality of workpieces W in the field of view of the CCD camera 12, Along with the position of W, the direction, front and back, or type of the workpiece W can be detected in a short time.

  According to the present boxing system 1, in order to detect the direction of the workpiece W transferred by the belt conveyor 20 or the like, the state of the front or back or the kind, and to control the transfer device 10 according to the detected state, It can be stored in the box B with its orientation, front and back, varieties, etc. aligned.

  In addition, the object to which the transfer apparatus 10 in this embodiment is applied is not limited to the above-described boxing system 1. For example, the present invention may be applied to a system that performs palletizing for aligning a plurality of workpieces W on a pallet, loading into a transporter such as a shipping truck, and the like.

  The present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

  As described above, according to the present invention, after the transmitted illumination image is captured, the reflected illumination image is captured, and based on the position of the workpiece detected from the transmitted illumination image, the reference illumination image is compared with the reference image. Since the target range for pattern matching is limited and pattern matching is performed for the limited target range, the state of the workpiece can be accurately detected, and particularly when there are a plurality of workpieces in the field of view of the imaging means, Since the position and state of the workpiece can be detected in a short time, it may be suitably used in the manufacturing industry of this type of transfer device or a boxing system equipped with the transfer device.

DESCRIPTION OF SYMBOLS 1 Boxing system 10 Transfer apparatus 11 Robot (conveyance means)
12 CCD camera (imaging means)
13 Light source for reflection illumination (reflection illumination means)
14 Light source for transmitted illumination (transmitted illumination means)
15 Controller (control means)
105 Robot controller (conveyance controller)
121 Position Detection Unit 122 Target Range Limiting Unit 123 Pattern Matching Processing Unit 124 State Detection Unit B Box W Work

Claims (3)

A transfer device comprising an image pickup means for picking up one or a plurality of workpieces, and a transfer means for transferring the workpieces, wherein the transfer device comprises:
Reflected illumination means provided at a position where reflected light from the surface of the workpiece is incident on the imaging means;
Transmitted illumination means provided across the workpiece on the line of sight of the imaging means;
Control means for capturing a reflected illumination image of the workpiece illuminated by the reflective illumination means after the image capturing means captures a transmitted illumination image of the workpiece illuminated by the transmitted illumination means;
The control means includes
A position detection unit that detects the position of the workpiece based on the contour of the workpiece extracted by processing the signal of the transmitted illumination image;
Of the reflected illumination image, a target range limiting unit that limits a target range of pattern matching performed later to a predetermined range based on the detected position;
A pattern matching processing unit that performs the pattern matching with a reference image for the limited target range;
A state detector that detects the state of the workpiece based on the result of the pattern matching;
A transfer control unit for transferring the workpiece by controlling the transfer means according to the detected position and the state;
A transfer apparatus comprising: The transfer device according to claim 1, wherein the state detection unit detects at least one of a direction, a front side, a back side, and a product type of the workpiece as the state of the workpiece. Comprising the transfer device;
The boxing system according to claim 1, wherein the workpiece is stored in a box by the transfer device.

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