Code reader system and method using the code reader system
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KEYENCE CORP
- Filing Date
- 2025-01-24
- Publication Date
- 2026-08-05
Smart Images
Figure 2026126609000001_ABST
Abstract
Description
Technical Field
[0004] , , ,
[0006] , , ,
[0005] , , , ,
[0001] The present disclosure relates to a code reader system and a method using the code reader system.
Background Art
[0002] Patent Document 1 discloses a code reader that images a code attached to a workpiece conveyed by a conveying device and reads the code included in the imaged image. This type of code reader is used, for example, at a logistics site or the like.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, when imaging the code attached to the workpiece, there may be a case where all the areas necessary for decoding cannot be imaged at once. Typically, it is a scene where the code on the bottom surface is read through the gap of the conveyor when the code is attached to the bottom surface of the workpiece, but in addition to this, there may be a case where all the areas necessary for decoding cannot be imaged at once.
[0005] When all the areas necessary for decoding cannot be imaged at once, it is considered that a composite image can be generated by synthesizing a plurality of images obtained by imaging the conveyed workpiece a plurality of times, and decoding processing can be executed on the generated composite image, thereby enabling the reading of the code.
[0006] However, even if the composite image looks good to the naked eye of the user, it is not always the case that the image quality is suitable for decoding processing. Generally, this tendency becomes stronger as the number of syntheses executed to obtain the composite image, that is, the number of images used, increases. [[ID=]]
[0007] However, in environments where code readers are in operation, users who utilize the code readers rarely understand the characteristics of composite images as described above. Even if decoding fails because the composite image is unsuitable for decoding, users will only perceive it as a normal composite image, resulting in a situation where the cause of the decoding failure cannot be identified.
[0008] This disclosure addresses the above issues by calculating and presenting to users an index indicating the accuracy of the composite image. [Means for solving the problem]
[0009] To achieve the above objective, one aspect of this disclosure may provide a code reader system comprising: a code reader for reading codes attached to workpieces being transported on a conveyor; and a management device connected to the code reader and a display device for displaying information from the code reader on the display device.
[0010] The code reader includes a camera that takes multiple images of the workpiece; a memory that stores multiple images output from the camera; a synthesis processing unit that generates a composite image by performing a synthesis process on the multiple images stored in the memory based on the image characteristics of each of the multiple images; a decoding unit that performs a decoding process on the composite image generated by the synthesis processing unit; a calculation unit that calculates an index indicating the accuracy of the synthesis processing of the multiple images by the synthesis processing unit; and an output unit that outputs the result of the decoding process by the decoding unit and the index calculated by the calculation unit to the management device. The management device can display the index calculated for the composite image for which the decoding process by the decoding unit failed on the display device.
[0011] In this configuration, multiple images output from the camera are combined in the synthesis processing unit to obtain a composite image. The decoding unit then performs decoding on the obtained composite image. If the decoding process by the decoding unit fails, an index indicating the accuracy of the failed composite image is displayed on the display device. At this time, the composite image and the index may be displayed in association, or only the index may be displayed. In any case, since the index is calculated by the calculation unit, it is an index that allows for a more appropriate determination of whether or not the image is suitable for decoding compared to the user's visual judgment of the composite image. Therefore, even if the user judges that the code is contained in a composite image that appears normal at first glance when the decoding process fails, if a low index is displayed on the display device, the user can understand that the composite image was not suitable for decoding, thus avoiding spending more time than necessary to identify the cause of the decoding process failure.
[0012] Furthermore, in another aspect of this disclosure, a method using a code reader system may be assumed. The method using a code reader system includes the steps of: capturing images of the workpiece multiple times with the camera of the code reader; generating a composite image by performing a composite processing of the multiple images based on the image features of each of the multiple images using the composite processing unit of the code reader; performing a decoding process on the composite image using the decoding processing unit of the code reader; calculating an index indicating the accuracy of the composite of the multiple images using the calculation unit of the code reader; outputting the result of the decoding process and the index to the management device using the output unit of the code reader; and causing the management device to display the index calculated for the composite image for which the decoding process failed on the display device. [Effects of the Invention]
[0013] As explained above, since an indicator showing the accuracy of the composite image for which the decoding process failed can be displayed on the display device, it becomes easier to identify the cause of the decoding failure.
Brief Description of the Drawings
[0014] [Figure 1] FIG. 1 is a perspective view for explaining the operation of a code reader according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of the code reader. [Figure 3] FIG. 3 is a view for explaining the operation of the code reader, showing the case when viewed from the upstream side in the conveyance direction. [Figure 4] FIG. 4 is a plan view for explaining the operation of the code reader. [Figure 5] FIG. 5 is a schematic diagram showing the relationship between the shine-proof optical system and the in-focus plane. [Figure 6A] FIG. 6A is a view showing a state where a code attached to the bottom surface of a workpiece is imaged from the side of the conveyance device and below the conveyance surface. [Figure 6B] FIG. 6B is a view showing the relationship between the visual field range, the in-focus plane, and the in-focus range of the code reader according to the present embodiment. [Figure 7] FIG. 7 is a view showing an example of installing the code reader directly below the conveyance device. [Figure 8] FIG. 8 is a view showing an example of installing a code reader with a light receiving window less than 90 degrees with respect to the horizontal plane directly below the conveyance device. [Figure 9] FIG. 33 is a view showing an example of installing a code reader with a light receiving window less than 90 degrees with respect to the horizontal plane on the side of the conveyance device. [Figure 10] FIG. 10 is a view showing an example of installing a code reader with a light receiving window exceeding 90 degrees with respect to the horizontal plane directly below the conveyance device. [Figure 11] [[ID=�9]]FIG. 11 is a view for explaining the state of imaging the bottom surface of a workpiece during conveyance. [Figure 12] FIG. 12 is a flowchart showing an example of a series of processes from imaging to output of a reading result. [Figure 13] FIG. 13 is a view for explaining the case of imaging the bottom surface of a workpiece during conveyance from the side of the conveyance device. [Figure 14]FIG. 14 is a flowchart showing an example of a presentation process of an index indicating the accuracy of a synthesis process. [Figure 15] FIG. 15 is a diagram showing an example of a synthesis process. [Figure 16] FIG. 16 is a diagram showing an example of display of an index when the accuracy of the synthesis process is sufficiently high. [Figure 17] FIG. 17 is a diagram showing an example of display of an index when the accuracy of the synthesis process is relatively high. [Figure 18] FIG. 18 is a diagram showing an example of display of an index when the accuracy of the synthesis process is low. [Figure 19] FIG. 19 is a diagram showing an example of display of an index when the decoding process fails. [Figure 20] FIG. 20 is a diagram corresponding to FIG. 1 when the code reader system includes a plurality of code readers. [Figure 21] FIG. 21 is a front view showing an operation state when the code reader system includes a plurality of code readers. [Figure 22] FIG. 22 is a diagram showing an example of a display screen that can be used when removing a fixed pattern for image writing-in. [Figure 23] FIG. 23 is a diagram showing an example of a setting screen for determining an invalid area.
Embodiments for Carrying Out the Invention
[0015] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses. For example, the relative sizes and positional relationships of the respective members shown in the figures are for the purpose of explaining one embodiment and do not limit the present invention.
[0016] Figure 1 is a schematic diagram showing the operation of a code reader system S according to an embodiment of the present invention. The code reader system S comprises a code reader 1 that reads codes attached to workpieces W being transported on a conveyor B, and a computer 200. Figure 2 is a block diagram of the code reader 1 included in the code reader system S.
[0017] Computer 200 is an example of a management device, connected to the code reader 1 and the display device 210, and causes the code reader 1's information to be displayed on the display device 210. The code reader system S may or may not include the display device 210. Computer 200 and the display device 210 may be integrated or separate. Computer 200 may be a general-purpose computer that functions as a management device by installing a program, or it may be a computer dedicated to the code reader system S.
[0018] Furthermore, an operation unit 220 is connected to the computer 200. The operation unit 220 consists of operating devices for operating the computer 200, and includes, for example, a keyboard 220a and a mouse 220b. The operation unit 220 may also include other operating devices besides the keyboard 220a and mouse 220b, such as a pointing device. The code reader system S may or may not include the operation unit 220.
[0019] This embodiment describes a case where the code reader system S is used in a logistics site handling multiple workpieces W. The logistics site is equipped with a conveying device B for sequentially conveying multiple workpieces W in a predetermined conveying direction. The conveying direction of the workpieces W is indicated by arrow A, and therefore the right side of Figure 1 is the upstream side in the conveying direction, and the left side of Figure 1 is the downstream side in the conveying direction.
[0020] The conveying device B has multiple conveying mechanisms B1 and B2 as conveyor elements. Each conveying mechanism B1 and B2 is composed of, for example, a belt conveyor, and includes an upstream conveying mechanism B1 and a downstream conveying mechanism B2. The upper surfaces of the upstream conveying mechanism B1 and the downstream conveying mechanism B2 form the conveying surface. In this embodiment, the conveying direction of the workpiece W is defined as the Y direction, the direction perpendicular to the Y direction on the conveying surface is defined as the X direction, and the direction perpendicular to both the X and Y directions is defined as the Z direction. In logistics sites, the X and Y directions are often approximately horizontal, but the Y direction may be inclined with respect to the horizontal plane. The X direction can also be called the width direction of the conveying mechanisms B1 and B2, or the longitudinal direction of the gap in the conveying device B. The Z direction can also be called the height direction (up and down direction). Note that these direction definitions are for the convenience of explanation and do not limit the direction in which the device is used.
[0021] The upstream conveying mechanism B1 and the downstream conveying mechanism B2 are spaced apart in the conveying direction. The size (dimensions) of the gap between the upstream conveying mechanism B1 and the downstream conveying mechanism B2 is not particularly limited, but it is set so that the smallest workpiece W being conveyed does not fall through the gap and is smoothly transferred from the upstream conveying mechanism B1 to the downstream conveying mechanism B2. The longitudinal dimension of the gap (dimension in the X direction) is approximately the same as the width (dimension in the X direction) of conveying mechanisms B1 and B2, but this is also not particularly limited.
[0022] The upstream conveying mechanism B1 and the downstream conveying mechanism B2 are supported on the floor surface C (shown in Figure 3) by members such as legs B3. As a result, the conveying surfaces of the upstream conveying mechanism B1 and the downstream conveying mechanism B2 are positioned a predetermined distance above the floor surface C, so a space may be formed below the upstream conveying mechanism B1 and the downstream conveying mechanism B2.
[0023] The code reader 1 is installed in a position set to the side of the conveying device B and below the conveying surface of the conveying device B. That is, as shown in Figure 1, when the widthwise edge of the conveying device B is projected vertically downward, that edge lies on a virtual line L1. The virtual line L1 is a straight line extending in the Y direction. In a top view, the area outside the conveying device B beyond the virtual line L1 can be defined as the side of the conveying device B. As also shown in Figures 3 and 4, the installation position of the code reader 1 in this embodiment is to the side of the conveying device B and is set directly beside the gap between the conveying mechanisms B1 and B2.
[0024] The dashed line indicated by reference numeral 8 in Figures 1 and 2 indicates the field of view of the imaging unit 3 (shown in Figure 2) of the code reader 1, although details will be described later. The imaging unit 3 corresponds to the camera of the present invention, and the code reader 1 is installed in a position such that the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2 is within the field of view of the imaging unit 3. Therefore, the code reader 1 of this embodiment is a stationary type. The operation of this stationary code reader 1 is when it is sequentially reading the codes of the workpieces W being transported by the transport device B. The code reader 1 can be fixed to the vertical fixed surface of the frame F fixed to the floor surface C, as shown in Figure 3, via the mounting structure 71A described later, but it may also be fixed via a stand or bracket (not shown), placed and fixed directly on the floor surface C, fixed to the transport mechanisms B1 and B2, or fixed to the leg portion B3, and its installation target is not particularly limited.
[0025] Since the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2 is within the field of view of the imaging unit 3, when the bottom surface of the workpiece W passes through the gap during transport, the bottom surface can be imaged by the imaging unit 3. A code may be attached to the bottom surface of the workpiece W. If a code is attached to the bottom surface of the workpiece W, the code reader 1 is installed at a position below the transport surface of the transport device B, so the code attached to the bottom surface of the workpiece W can be read from below the transport surface of the transport device B through the gap.
[0026] The codes attached to the workpiece W include both barcodes and two-dimensional codes. Examples of two-dimensional codes include QR code (registered trademark), micro QR code, data matrix (Data code), Veri code, Aztec code, PDF417, and Maxi code. Two-dimensional codes come in stacked and matrix types, but the present invention is applicable to any type of two-dimensional code. The codes may be attached to the workpiece W by printing or engraving them directly, or by printing them on a label and then attaching it to the workpiece W; the means and method are not limited.
[0027] As shown in Figure 1, the code reader 1 is wired to the computer 200 and the programmable logic controller (PLC) 201 by signal lines 200a and 201a, respectively. However, it is not limited to this configuration; wireless communication modules may be built into the code reader 1, computer 200, and PLC 201 to wirelessly connect the code reader 1 to the computer 200 and PLC 201. The PLC 201 is a control device for sequence control of the transport device B and the code reader 1, and a general-purpose PLC can be used. The computer 200 can be a general-purpose or dedicated electronic computer or a portable terminal.
[0028] Furthermore, during operation, the code reader 1 receives a read start trigger signal from the PLC 201 via signal line 201a, which defines the start timing for code reading. Based on this read start trigger signal, the code reader 1 images and decodes the code. The decoded result is then transmitted to the PLC 201 via signal line 201a. In this way, during operation of the code reader 1, the input of the read start trigger signal and the output of the decoded result are repeatedly performed between the code reader 1 and an external control device such as the PLC 201 via signal line 201a. Note that the input of the read start trigger signal and the output of the decoded result may be performed via signal line 201a between the code reader 1 and the PLC 201, as described above, or via other signal lines not shown. For example, a sensor for detecting the arrival of workpiece W may be directly connected to the code reader 1, and the read start trigger signal may be input from that sensor to the code reader 1.
[0029] As shown in Figure 2, the code reader 1 is connected to an encoder 70 and a timing sensor 71. The encoder 70 is a device capable of detecting the transport speed of the transport device B. Based on the information output from this encoder 70 (encoder information), the code reader 1 can acquire the transport speed. The timing sensor 71 is a sensor that detects when the workpiece W arrives at a predetermined position and when it leaves that position. Using this timing sensor 71, the code reader 1 can acquire the predicted transport speed.
[0030] The code reader 1 includes, for example, an illumination unit 2, an imaging unit 3, a control unit 4, a storage unit 5, and a communication unit 6. The control unit 4 includes an imaging control unit 41 that controls the imaging unit 3, an illumination control unit 42 that controls the illumination unit 2, a synthesis processing unit 43, a code detection unit 44, a decoding unit 45, a calculation unit 46, and an output unit 47. The imaging unit 3 and the decoding unit 45 may be separate units. Similarly, the imaging unit 3, the calculation unit 46, and the output unit 47 may be separate units.
[0031] As a specific example of the configuration of the control unit 4, for example, a configuration including a microcomputer having a central processing unit, ROM, RAM, etc. is given. The hardware included in the control unit 4 and the software executed by the control unit 4 constitute the imaging control unit 41, illumination control unit 42, synthesis processing unit 43, code detection unit 44, decoding unit 45, calculation unit 46, and output unit 47. The imaging control unit 41, illumination control unit 42, synthesis processing unit 43, code detection unit 44, decoding unit 45, calculation unit 46, and output unit 47 may be made up of common hardware or different hardware. In addition, parts of the imaging control unit 41, illumination control unit 42, synthesis processing unit 43, code detection unit 44, decoding unit 45, calculation unit 46, and output unit 47 may be provided outside the housing 60 of the code reader 1.
[0032] Furthermore, the storage unit 5 can be configured as a read / write storage device such as an SSD (Solid State Drive). The storage unit 5 can store various programs, decoding results, image data, setting information, etc., and has a decoding result storage unit 51, an image data storage unit 52, and a setting storage unit 53. The decoding result storage unit 51, the image data storage unit 52, and the setting storage unit 53 may be provided in separate storage devices, although these are not shown in the figures.
[0033] The communication unit 6 is the part that performs communication with the computer 200 and the PLC 201. The control unit 4 receives the setting information from the computer 200 via the communication unit 6. The control unit 4 also receives the read start trigger signal from the PLC 201 via the communication unit 6. The decoding result from the code reader 1 is transmitted to the computer 200 and the PLC 201 via the communication unit 6. The communication unit 6 also receives the dimensions of the gaps formed between the multiple transport mechanisms B1 and B2 of the transport device B, and the transport speed of the transport device B. The gap dimensions and transport speed can be pre-entered by the user into the computer 200, etc. The entered gap dimensions and transport speed are stored in the computer 200, and after being transmitted from the computer 200, the communication unit 6 receives and acquires them.
[0034] The lighting unit 2 is the part that illuminates the workpiece W with illumination light, and the illumination range of the lighting unit 2 includes the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2. Since the code reader 1 is installed to the side of the transport device B and below the transport surface of the transport device B, the lighting unit 2 illuminates the gap from below the transport surface. As a result, when the bottom surface of the workpiece W passes through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2 during transport, the bottom surface can be illuminated by the lighting unit 2. If a code is attached to the bottom surface of the workpiece W, the code attached to the bottom surface of the workpiece W can be illuminated by the lighting unit 2.
[0035] The illumination unit 2 and the imaging unit 3 may be integrated, or they may be separate units. The illumination unit 2 is controlled by the illumination control unit 42, which switches between turning it on and off and changes the brightness when it is lit. When a read start trigger signal is input from the PLC 201, the illumination control unit 42 turns on the illumination unit 2 for a predetermined time and turns it off after the predetermined time has elapsed.
[0036] The imaging unit 3 is the part that images the workpiece W through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2, generates a code image that includes the code, and outputs it to the control unit 4. The imaging unit 3 has a Shineproof optical system 31, a preprocessing circuit 32, and a planar mirror 33. As shown in Figure 5, the Shineproof optical system 31 has a lens 31a and an image sensor 31b having a light-receiving surface inclined with respect to the optical axis 10 of the lens 31a. The lens 31a is an imaging lens that focuses reflected light from the bottom surface of the workpiece W. The light incident on the lens 31a is emitted toward the light-receiving surface of the image sensor 31b and forms an image on the light-receiving surface.
[0037] The planar mirror 33 is a component for directing light incident on the imaging unit 3 towards the lens 31a. In other words, in this example, since there is a shineproof optical system 31, the focal plane 7 is formed to extend in the V direction of the image sensor 31b. Figure 6A shows the state in which a code attached to the bottom surface of the workpiece W is imaged from the side of the transport device B and below the transport surface. Figure 6A also shows the shape of the focal plane 7 formed on the light-receiving surface of the image sensor 31b, where the near side is relatively close to the code reader 1 and the far side is relatively far from the code reader 1. As shown in Figure 6A, the gap between the workpiece W and the transport device B appears larger at the near side compared to the far side. In other words, the bottom surface of the workpiece W visible through the gap in the transport device B is projected onto the image sensor 31b as a trapezoidal shape, with one end on the near side, which is relatively closer to the imaging unit 3, being the longer side, and the other end on the far side, which is relatively farther from the imaging unit 3, being the shorter side.
[0038] In Figure 6B, the field of view of the imaging unit 3 is indicated by reference numeral 8, and the range in focus is indicated by reference numeral 9. The optical axis extending through the center of the field of view 8 (the optical axis of lens 31a) is indicated by reference numeral 10. Thus, the Scheinproof optical system 31 has a tilt of the focal plane 7 in the V direction of the image sensor 31b.
[0039] As shown in Figures 1, 3, and 4, when installing the code reader 1 below the transport surface of the transport device B, the installation position and angle of the code reader 1 are adjusted so that the depth of field 9 of the Scheinproof optical system 31 includes the gap in the transport device B, and the focal plane 7 of the Scheinproof optical system 31 is approximately parallel to the transport surface.
[0040] The image sensor 31b includes a light-receiving element such as a CCD (charge-coupled device) or CMOS (complementary metal oxide semiconductor) that converts the image of the code obtained through the lens 31a into an electrical signal. The image sensor 31b generates an image containing the code based on the amount of light received at the light-receiving surface of the image sensor 31b. The image sensor 31b has multiple image sensors arranged in the row and column directions. In other words, the imaging unit 3 is an area camera that generates an image in which multiple pixels are arranged in two dimensions. The image sensor 31b of the imaging unit 3 is configured such that the row direction substantially coincides with the direction from the near side to the far side of the focal plane of the Shineproof optical system 31.
[0041] In other words, if we assume that a line sensor is used as an image sensor, high-speed readout is possible, but reading the code would require an extremely high frame rate, which could increase the amount of heat generated by the illumination unit 2. In this embodiment, however, an area sensor with multiple image sensors arranged in the row and column directions is used as the image sensor 31b, and by partially reading the data, it is possible to achieve both heat suppression and high-speed readout.
[0042] The image generated by the image sensor 31b is input to the preprocessing circuit 32. The preprocessing circuit 32 can be provided as needed and is not mandatory.
[0043] The preprocessing circuit 32 is composed of an integrated circuit such as an FPGA (Field Programmable Gate Array) and is responsible for performing various preprocessing operations on the image output from the image sensor 31b. Preprocessing includes, for example, various filtering operations. The imaging unit 3 outputs the image that has been preprocessed by the preprocessing circuit 32 to the control unit 4. Preprocessing by the preprocessing circuit 32 may be performed as needed, and images that have not been preprocessed may also be output to the control unit 4. The images output to the control unit 4 are stored in the image data storage unit 52 of the storage unit 5.
[0044] The imaging unit 3 is controlled by the imaging control unit 41. When a read start trigger signal is input from the PLC 201, the imaging control unit 41 generates an image by exposing it for a preset exposure time. By controlling the imaging unit 3, the imaging control unit 41 also applies a preset gain to the image generated by the image sensor 31b and performs a process to amplify the brightness of the image through digital image processing. In addition, the imaging control unit 41 determines the frame rate (number of images taken per second) of the imaging unit 3 based on the dimensions of the gap between the transport mechanisms B1 and B2 (gap width) and the transport speed received by the communication unit 6. For example, the imaging control unit 41 increases the frame rate of the imaging unit 3 as the transport speed increases. The frame rate can be set, for example, in the range of 500fps to 5000fps. As the frame rate increases, stronger light is required to obtain sufficient brightness with a shorter exposure time, so the amount of heat generated by the illumination unit 2 increases proportionally.
[0045] The installation location of the code reader 1 is not limited to the side of the transport device B. In other words, as shown in Figure 7, for example, if there is sufficient space directly below the transport device B, the code reader 1 can also be installed directly below the transport device B. For example, if the code reader 1 is installed so that the optical axis of the lens 31a is approximately parallel to the transport direction A in a top view, the imaging unit 3 can be configured to image the bottom surface of the workpiece W from the installation position via the mirror D, which acts as an external reflective member. In this case, the mirror D, which extends approximately vertically, is installed on the side of the transport device B, and the reflected light from the bottom surface of the workpiece W is incident on the mirror D, reflected downwards, incident on the light-receiving window 67 formed in the housing 60 of the code reader 1, passes through the light-receiving window 67, and incident on the imaging unit 3. The code reader 1 in the example shown in Figure 7 is configured to include an external reflective member (mirror D) located outside the housing 60.
[0046] In this example, the angle at which the light-receiving window 67 intersects the horizontal plane is set to 90 degrees, but this is not the only option. As shown in Figure 8, when the code reader 1 is installed directly below the transport device B, the inclination angle α of the light-receiving window 67 with respect to the horizontal plane E may be less than 90 degrees. The inclination angle α may be, for example, 20 degrees or more, or 45 degrees or more.
[0047] Furthermore, as shown in Figure 9, a code reader 1 with a light-receiving window 67 at an angle of less than 90 degrees with respect to the horizontal plane E may be installed to the side of the conveying device B. Alternatively, as shown in Figure 10, a code reader 1 with a light-receiving window 67 at an angle greater than 90 degrees with respect to the horizontal plane E may be installed directly below the conveying device B. In this case, similar to the example shown in Figure 7, the reflected light from the bottom surface of the workpiece W is incident on the mirror D, reflected downwards, and then incident on the light-receiving window 67.
[0048] Regardless of the installation configuration shown in Figures 1, 3, 4, 7 to 10, once the housing 60 is installed, the distance between the light-receiving window 67 and the gap in the transport device B, the orientation of the light-receiving window 67 relative to the gap, etc., are determined. When the housing 60 is installed with the light-receiving window 67 positioned to face the longitudinal direction of the gap in the transport device B, the imaging unit 3 is configured such that the depth of field (the range in which the Scheinproof optical system 31 is in focus) includes the gap in the transport device B. In this case, the gap will be included in the middle portion of the depth of field of the Scheinproof optical system 31.
[0049] When a workpiece W is transported using the transport device B shown in Figure 1, the bottom surface of the workpiece W being transported by the transport device B is exposed downwards through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2. As shown in Figures 1, 3, 4, and 7-10, the depth of field of the imaging unit 3 of the installed code reader 1 includes the bottom surface of the workpiece W exposed through the gap in the transport device B. As a result, the imaging unit 3 can image the bottom surface of the workpiece W through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2. During this imaging, the row direction of the image sensor 31b corresponds to the direction in which the gap in the transport device B extends, and the column direction of the image sensor 31b corresponds to the transport direction of the transport device B (the direction indicated by arrow A in Figure 1).
[0050] Therefore, as shown in Figure 11, the imaging unit 3 continuously images the bottom surface of the workpiece W, which is exposed through the gap in the transport device B and included in the depth of field of the imaging unit 3, thereby outputting multiple images that capture a portion of the code attached to the bottom surface of the workpiece W. The upper part of Figure 11 shows the upstream transport mechanism B1 and the downstream transport mechanism B2 that are transporting the workpiece W, viewed from below, with the workpiece W being transported as shown from left to right. Since the dimension of the code in the transport direction is longer than the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2, only a portion of the code in the transport direction is exposed downwards through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2. As shown in the lower part of Figure 11, multiple images capturing a portion of the code in the transport direction are sequentially output from the imaging unit 3. The multiple images output from the imaging unit 3 are input to the control unit 4. The images output from the imaging unit 3 become elongated images in the longitudinal direction of the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2 through geometric correction described later.
[0051] Multiple images output from the imaging unit 3 are stored in the image data storage unit (memory) 52. The synthesis processing unit 43 acquires the multiple images stored in the image data storage unit 52. The synthesis processing unit 43 generates a composite image by performing a synthesis process on the multiple images based on the image features of each acquired image. The image features can be, for example, at least one local feature or edge feature from ORB (Oriented FAST and Rotated BRIEF), SURF (Speeded-Up Robust Features), and SIFT (Scale-Invariant Feature Transform).
[0052] The code detection unit 44 of the control unit 4 identifies a code region based on the composite image generated by the synthesis processing unit 43 and detects a code from the identified code region. The decoding unit 45 of the control unit 4 performs decoding on the composite image generated by the synthesis processing unit 43. Specifically, the decoding unit 45 decodes the code detected by the code detection unit 44. For example, since the code is represented by grayscale binarized data, the decoding unit 45 decodes the grayscale binarized data. A table showing the correspondence between encoded data can be used during the decoding process. Furthermore, the decoding unit 45 checks whether the decoded result is correct according to a predetermined checking method. If an error is found in the data, an error correction function is used to calculate the correct data. The error correction function differs depending on the type of code.
[0053] The following describes the series of processes from image acquisition to output of the reading result, based on the flowchart shown in Figure 12. This flowchart starts when the operation of the code reader 1 is initiated. In step SA1 after the start, a reading start trigger signal is input from the PLC 201 to the code reader 1. When the reading start trigger signal is input, the illumination control unit 42 turns on the illumination unit 2, and the imaging control unit 41 causes the imaging unit 3 to take an image and generate an image.
[0054] The area enclosed by the dashed line in Figure 13 is the image output from the imaging unit 3. When the code reader 1 is installed to the side of the transport device B, the bottom surface of the workpiece W is imaged from diagonally below. Therefore, unlike when imaged from directly below, geometric changes occur depending on the installation angle of the code reader 1, as shown in Figure 13. Specifically, in the multiple images output from the imaging unit 3, the bottom surface of the workpiece W exposed through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2 is depicted as a trapezoidal shape, with one end near the focal plane of the Shineproof optical system 31 being the longer side and the other end far from the focal plane of the Shineproof optical system 31 being the shorter side.
[0055] Therefore, in step SA2 of the flowchart shown in Figure 12, the synthesis processing unit 43 performs trapezoidal correction on the trapezoidal shape of multiple images as geometric correction. Specifically, the synthesis processing unit 43 acquires information regarding the installation angle of the code reader 1. This information regarding the installation angle of the code reader 1 may be information entered by the user when setting up the code reader 1, or it may be information automatically detected by the code reader 1. Based on the information regarding the installation angle of the code reader 1, the synthesis processing unit 43 performs geometric correction on each of the multiple images output from the imaging unit 3. This results in an image similar to that obtained when imaging from directly below the workpiece W. Note that imaging may also be performed from directly below the workpiece W, in which case the geometric correction step can be omitted.
[0056] In step SA3, the synthesis processing unit 43 synthesizes multiple processed images, which have undergone geometric correction in step SA2, to generate a composite image containing the code. Since the synthesis of multiple images is based on the image characteristics of each of the multiple images captured using the area camera, the composite image can be generated while tolerating fluctuations in the transport speed.
[0057] The synthesis processing unit 43 synthesizes partial images consisting of parts of each of the multiple images and multiple rows. More specifically, the synthesis processing unit 43 determines the overlap width of the multiple images in the conveying direction of the conveyor based on the size of the synthesized image, the sizes of the multiple images, the conveying speed of the conveying device B, and the installation conditions of the code reader 1. At least one of a predetermined lower limit and upper limit is set for the overlap width. That is, if there is no upper limit for the overlap width, it may occur that the multiple images are completely superimposed on each other, in which case the synthesis process will not be completed. By setting an upper limit for the overlap width, the synthesis process can be completed. On the other hand, if there is no lower limit for the overlap width, the images will simply be concatenated, but by setting a lower limit, appropriate synthesis processing becomes possible.
[0058] Step SA4 determines whether the number of imaging cycles performed by the imaging unit 3 has reached the specified number. This number is set to the number of times the entire code can be imaged. If step SA4 determines NO, the process proceeds to step SA1, and imaging, geometric correction, and image synthesis are repeated until the entire code has been imaged. If step SA4 determines YES, the process proceeds to step SA5.
[0059] In step SA5, the code detection unit 44 generates multiple edge images by applying multiple edge extraction filters to the image synthesized in step SA3 to extract edges of different frequencies, and then performs integration processing of the multiple edge images. Based on the results of the edge integration processing, the code detection unit 44 determines the candidate code locations. That is, in the edge-processed image, regions where many pixels with high brightness values are concentrated can be estimated as code regions.
[0060] For example, the code detection unit 44 can generate a heatmap image that represents the likelihood of a code being present in order to search for the location of a code within a code image. That is, the code detection unit 44 quantifies the features of the code, generates a heatmap by assigning the magnitude of the features to each pixel value, and extracts code candidate regions on the heatmap that are highly likely to contain a code. A specific example is to acquire the feature portion of the code in regions that are relatively hot (have large features) in the heatmap. If multiple feature portions are acquired, they can be prioritized and extracted and stored in RAM or the like. By using a heatmap image, it becomes possible to detect code regions at high speed. The decoding unit 45 decodes the code searched by the code detection unit 44.
[0061] By performing the synthesis process in step SA3, a synthesized image can be obtained. However, even if the synthesis position is slightly off, the user may visually perceive the synthesis as successful. However, with synthesized images where the synthesis position is off, the decoding process by the decoding unit 45 may fail. Therefore, when the decoding process fails, it is difficult for the user to determine whether the problem lies in the synthesis process or the decoding process.
[0062] In this embodiment, by providing the user with an indicator showing the accuracy of the synthesis process, it is possible to easily determine whether the cause of a decoding failure was due to the synthesis process or the decoding process. The details of the process for providing the indicator showing the accuracy of the synthesis process will be explained below based on the flowchart shown in Figure 14.
[0063] The flowchart shown in Figure 14 starts when the code reader 1 is put into operation. In step SB1, the calculation unit 46 calculates the expected number of images required to generate the composite image, based on the size of the composite image, the sizes of the multiple images captured by the imaging unit 3 (captured image size), the transport speed of the transport device B, and the installation conditions of the code reader 1. At this time, the calculation unit 46 also acquires the overlap pixel amount d.
[0064] Specifically, as shown in Figure 15 as an example, when generating a single composite image 110 by combining the first to third captured images 101, 102, and 103, let h be the height of each of the first to third captured images 101, 102, and 103, and let y be the amount of movement between the first captured image 101 and the second captured image 102. The amount of movement y is the amount of movement in the transport direction and can also be called the transport amount. The overlap pixel amount d is the amount of overlap (overlap width) in the transport direction between the first captured image 101 and the second captured image 102, and may be a fixed value or may be determined based on the user's selection of the synthesis mode. The synthesis mode includes different modes depending on, for example, the transport speed, and the overlap pixel amount d is changed depending on the synthesis mode.
[0065] Furthermore, let H be the height of the composite image 110 generated by the synthesis process. In this case, the calculation unit 46 calculates the expected number of images (n) that are expected to be necessary to generate the composite image based on the following formula.
[0066] n = (Hh) / y + 1 = (Hh) / (hd) + 1 In step SB2, the calculation unit 46 determines the frame rate (FPS) of the imaging unit 3 from the transport speed of the workpiece W and the expected number of images calculated in step SB1. An example of FPS calculation is described below. When the transport speed is V [mm / s], the transport direction size of the composite image is H [mm], H can also be said to be the transport distance of the workpiece W, the time T taken for transport is H / V [s], and the expected number of images is n [images], the FPS is calculated based on the following formula.
[0067] FPS = n / (H / V) = nV / H[FPS] Furthermore, when determining the transport direction size H [mm] of the composite image, it is necessary to convert the number of pixels to mm, so the camera parameters and installation conditions of Code Reader 1 are required. The camera parameters of Code Reader 1 include, for example, the number of pixels, pixel size, and field of view, while the installation conditions include, for example, the X coordinate, Y coordinate, Z coordinate, and tilt.
[0068] In step SB3, the imaging unit 3 performs imaging processing multiple times to acquire multiple images. In step SB4, the synthesis processing unit 43 determines whether there are pairs of images adjacent to each other in the time axis direction that have image features with a similarity of a predetermined value or higher. If it is determined to be YES, the process proceeds to step SB5. In step SB5, the synthesis processing unit 43 determines the overlap pixel amount d that maximizes the similarity within a predetermined forced shift amount range determined based on the lower and upper limits of the overlap width. In step SB6, the synthesis processing unit 43 performs synthesis processing with the overlap pixel amount d determined in step SB5. On the other hand, if it is determined to be NO in step SB4, the process proceeds to step SB7, where the synthesis processing unit 43 performs synthesis processing with the expected number of overlap pixel amounts d.
[0069] In step SB8, the synthesis processing unit 43 determines whether the synthesized image has reached a predetermined size through the synthesis process. If the result in step SB8 is NO and the synthesized image has not reached the predetermined size, the process returns to step SB3. On the other hand, if the result in step SB8 is YES and the synthesized image has reached the predetermined size, the process proceeds to step SB9.
[0070] In step SB9, the calculation unit 46 calculates an index indicating the accuracy of the image synthesis process performed by the image synthesis processing unit 43. For example, the calculation unit 46 counts the actual number of images used to generate the synthesized image and calculates an index indicating the accuracy of the synthesis process based on the difference between the expected number and the actual number. Alternatively, the calculation unit 46 can perform image analysis of the synthesized image and calculate an index indicating the accuracy of the synthesis process based on the analysis results.
[0071] When the calculation unit 46 calculates an index indicating the accuracy of the synthesis process based on the difference between the expected number of sheets and the actual number of sheets, it can be calculated using the following formula.
[0072] Index = 100 × {(Expected number of coins - Actual number of coins) / Expected number of coins} [%] An index indicating the accuracy of the synthesis process can be expressed as, for example, the deviation from the expected value, with "0" indicating that the synthesis process is as expected. On the other hand, a larger absolute value of this index indicates that there are more areas where the synthesis process failed, or that there are large synthesis deviations. The positive or negative sign indicates the direction in which the deviation is from the expected movement position. In other words, the calculation unit 46 can calculate an index that indicates whether the actual number of pieces is greater or less than the expected number.
[0073] The calculation unit 46 can also adjust the expected number of images in real time based on at least one of the encoder information and the predicted transport speed. By obtaining the transport speed, the optimal expected number of images according to the transport speed can be calculated. Note that the initially determined expected number of images remains fixed while one composite image is being synthesized.
[0074] The method for calculating the index indicating the accuracy of the synthesis process is not limited to the method described above. For example, the degree of alignment and color mismatch may be evaluated by the difference in pixel values of the overlapping parts of adjacent images in the time axis direction, and the index may be calculated based on the evaluation result. Alternatively, the feature points of adjacent images in the time axis direction may be compared to evaluate the degree of appropriate correspondence, and the index may be calculated based on the evaluation result. Furthermore, the degree of smoothness of the changes in color tone and brightness of adjacent images in the time axis direction may be evaluated, and the index may be calculated based on the evaluation result. Additionally, edges may be detected at the boundaries of adjacent images in the time axis direction, and the degree of brightness and shape continuity may be evaluated, and the index may be calculated based on the evaluation result.
[0075] In step SB10, the output unit 47 outputs the index calculated in step SB9 and the result of the decoding process by the decoding unit 45 to the computer 200, after which the computer 200 displays the index on the display device 210.
[0076] When displaying the index calculated in step SB9 on the display device 210, the computer 200 generates a display screen 300, such as the one shown in Figure 16, and displays it on the display device 210. The display screen 300 is provided with an image display area 301 in which the transport device B and the workpiece W are displayed, and an index display area 302. In Figure 16, an image of the bottom surface of the workpiece W is displayed in the image display area 301, and a composite image including the code attached to the bottom surface of the workpiece W is displayed. The index is displayed in the index display area 302 by the length of a bar, and the longer the bar, the higher the accuracy of the composite image.
[0077] The indicator display area 302 may display the indicator numerically, change the color of the bar according to the size of the indicator or the length of the bar, or display it using shades of color; the display format is not particularly limited. In Figure 16, the accuracy of the composite image is high, so the code is clear, as shown in the enlarged portion. Note that the enlarged portion is an example and does not need to be displayed on the actual display device 210. Also, in Figure 16, the accuracy of the composite image is high, so the bar is displayed in green, for example.
[0078] Figures 17, 18, and 19 are also examples of displaying indicators showing the accuracy of the synthesis process. Figure 17 shows an example where the synthesis accuracy is lower than in Figure 16, but the decoding process is successful. Since the synthesis accuracy is still relatively high, the bar, for example, continues to be displayed in green. Figure 18 shows an example where the synthesis accuracy is lower than in Figure 17, but the decoding process is successful. However, because the synthesis accuracy has further decreased, the bar is displayed in yellow, for example. As shown above, indicators may be displayed for synthesized images that have been successfully decoded, but they do not need to be displayed for synthesized images that have been successfully decoded.
[0079] On the other hand, Figure 19 shows an example of how the indicator is displayed when the decoding process fails. In the example shown in Figure 19, the composite image appears fine to the naked eye, but because the accuracy of the composite image is low, the lines that make up the code, which should be straight, are jagged, as shown in the magnified section. Therefore, the decoding process in the decoding unit 45 fails. Also, because the accuracy of the composite process is low, the bar is displayed in red, for example. In this way, the output unit 47 outputs the composite image that failed to decode and the indicator together to the computer 200, and the computer 200 can display the composite image that failed to decode and the indicator on the display device 210. The display format is not particularly limited, and the computer 200 may display only the indicator calculated for the composite image that failed to decode by the decoding unit 45 on the display device 210 without displaying the composite image. In any case, since an indicator showing the accuracy of the composite process can be presented to the user, it is possible to easily identify the cause of the decoding process failure.
[0080] Factors that can lower the accuracy of the synthesis process include changes in transport speed, such as the temporary suspension of transport device B, and cases where the code is farther than the transport surface, such as with rounded workpieces.
[0081] Each of the multiple images captured by the imaging unit 3 may contain a fixed pattern that remains visible regardless of time. This fixed pattern may include any of the following: parts of the transport device B, ceiling lighting, or ceiling patterns.
[0082] Furthermore, as shown in Figures 20 and 21, the code reader system S may be equipped with multiple code readers 1A, 1B, 1C, and 1D. Figures 20 and 21 show an example in which four code readers 1A, 1B, 1C, and 1D are used during operation, but the number of code readers used during operation is not limited to four; it can be any number of three or fewer, or five or more. Code reader 1A is designated as the first code reader 1A, code reader 1B as the second code reader 1B, code reader 1C as the third code reader 1C, and code reader 1D as the fourth code reader 1D.
[0083] The first to fourth code readers 1A, 1B, 1C, and 1D are configured to be usable when mounted on an external frame (hereinafter simply referred to as the frame) 830. The frame 830 is a frame-shaped frame formed to surround the conveying device B, and comprises a lower member 831 positioned below the conveying device B and extending in the width direction (X direction) of the conveying device B, a pair of lateral members 832 extending upward (Z direction) from both sides in the longitudinal direction of the lower member 831, and an upper member 833 extending in the width direction of the conveying device B so as to connect the upper ends of the pair of lateral members 832. The frame 830 is fixed to, for example, the floor surface C (shown in Figure 21).
[0084] A first code reader 1A for reading a code attached to the bottom surface of the workpiece W is mounted on the lower member 831. The optical axis of the first code reader 1A mounted on the lower member 831 is pointed upward, and the field of view of the first code reader 1A includes the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2.
[0085] Since the field of view of the first code reader 1A includes the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2, when the bottom surface of the workpiece W being transported passes through the gap between the upstream transport mechanism B1 and the downstream transport mechanism B2, the bottom surface can be imaged by the first code reader 1A.
[0086] A second code reader 1B for reading a code attached to one side of the workpiece W is mounted on one of the side members 832. The optical axis of the second code reader 1B mounted on one of the side members 832 is set to point toward one side of the workpiece W.
[0087] A third code reader 1C for reading a code attached to the other side of the workpiece W is mounted on the other side member 832. The optical axis of the third code reader 1C mounted on the other side member 832 is set to point towards the other side of the workpiece W.
[0088] A fourth code reader 1D for reading the code attached to the upper surface of the workpiece W is mounted on the upper member 833. The optical axis of the fourth code reader 1D mounted on the upper member 833 is pointed downwards.
[0089] The structure of the frame 830 described above is merely an example, and it does not have to be a frame-shaped frame. For example, it may be a frame consisting only of the lower member 831, a frame consisting only of the lateral member 832, or a frame consisting only of the upper member 833. It may also be a frame comprising any two of the lower member 831, lateral member 832, and upper member 833. Furthermore, it is not necessary for a code reader to be attached to all of the lower member 831, lateral member 832, and upper member 833; it is sufficient for a code reader to be attached to any one or any two or more of the lower member 831, lateral member 832, and upper member 833. The frame may also be fixed to, for example, the conveying device B or other members, equipment, etc. The shape of the frame may be straight, curved, or bent.
[0090] In the operational configurations shown in Figures 20 and 21, fixed patterns that appear in each image regardless of time changes may include the lighting of the code reader on the opposite side and the frame 830 on which the code reader is installed.
[0091] If the computer 200's indicator of the accuracy of the synthesis process falls below a predetermined value, it displays a message on the display device 210 recommending the removal of fixed patterns that appear in each image, regardless of how they change over time. The message prompts the user to either mask the fixed patterns or to change the placement of the code reader 1 so that the fixed patterns are not included. In this way, the user can be informed that the indicator can be improved by removing the fixed patterns.
[0092] Figure 22 shows a display screen 350 available to the user when removing a fixed pattern. The display screen 350 includes an overall image display area 351 that displays an image of the entire field of view of the imaging unit 3. In the figure, the hatched areas indicate areas not used during operation, and the areas other than the hatched areas (line-shaped areas) are used as part of the composite image. The position of the hatched areas can be changed by the user operating the operation unit 220. By moving the hatched areas so that they overlap with the fixed pattern, the fixed pattern can be removed. The display screen 350 is provided with a capture button 352. After determining the position of the hatched areas, when the user operates the capture button 352, the position of the hatched areas is applied during operation, and the areas other than the hatched areas are used for the composite processing. In this way, the computer 200 can display the display screen 350 on the display device 210 as a setting screen for determining the usable range to be used for actual imaging within the field of view of the code reader 1.
[0093] Furthermore, by looking at the display screen 350, the user can understand which part of the image the fixed pattern will appear in. Therefore, while looking at the display screen 350, the user can change the position of the code reader 1 so that the fixed pattern does not fall within the range used for actual imaging.
[0094] The computer 200 can also display a settings screen 360 (shown in Figure 23) on the display device 210 for determining invalid areas in the field of view of the code reader 1 that are not to be used as image features. To access this settings screen 360, the user operates the "Add invalid area" button 353 provided on the display screen 350 shown in Figure 22.
[0095] When the Add Invalid Area button 353 is operated, the computer 200 displays the setting screen 360 shown in Figure 23 on the display device 210. Similar to Figure 22, the hatched areas indicate areas that are not used during operation. The setting screen 360 for determining the invalid area includes an overall image display area 361 that displays an image of the entire field of view of the imaging unit 3, an invalid area deletion button 362, an Add Invalid Area button 363, a Cancel button 354, and an Apply button 365. When the Add Invalid Area button 363 is operated, an area display area 366 indicating the invalid area is superimposed on the overall image display area 361. The area where this area display area 366 overlaps is considered the invalid area. The size, shape, and position of the area display area 366 can be changed by the user. Therefore, the size, shape, and position of the invalid area can be arbitrarily determined, making it easy to remove fixed patterns. To delete an invalid area, simply operate the Delete Invalid Area button 362. Furthermore, if you want to set two or more invalid areas, simply use the "Add Invalid Area" button 363.
[0096] If the user has finished configuring the disabled area and then operates the Apply button 365, the disabled area settings will be applied during operation. On the other hand, if the Cancel button 354 is operated, the disabled area settings will not be applied during operation.
[0097] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. For example, although the embodiments described above describe an example in which the imaging unit 3 has a shine-proof optical system 31, the configuration of this disclosure can also be applied to code readers equipped with imaging units having optical systems other than the shine-proof optical system. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]
[0098] As explained above, the technology relating to this disclosure can be used to read the code attached to a workpiece. [Explanation of Symbols]
[0099] 1 Code Reader 3. Imaging unit (camera) 43 Synthesis Processing Unit 45 Decoding section 46 Arithmetic section 47 Output section 52 Image data storage unit (memory) 70 encoders 71 Timing Sensor 200 Computer (Management Device) 210 Display device B. Conveying device (conveyor) S Code Reader System B1, B2 Conveying mechanism (conveyor element)
Claims
1. A code reader that reads the code attached to a workpiece being transported on a conveyor belt, A management device connected to the code reader and display device, which displays the information from the code reader on the display device, A code reader system equipped with, The aforementioned code reader is A camera that takes multiple images of the aforementioned workpiece, A memory for storing multiple images output from the aforementioned camera, A synthesis processing unit generates a composite image by performing a synthesis process on the plurality of images based on the image characteristics of each of the plurality of images stored in the memory, A decoding unit that performs decoding on the composite image generated by the synthesis processing unit, A calculation unit that calculates an index indicating the accuracy of the synthesis processing of the multiple images by the synthesis processing unit, An output unit that outputs the result of the decoding process by the decoding unit and the index calculated by the calculation unit to the management device, Equipped with, The management device displays the index calculated for the composite image that failed to decode by the decoding unit on the display device. Code reader system.
2. In the code reader system according to claim 1, The output unit outputs the composite image that failed the decoding process and the index together to the management device. The management device causes the composite image and the indicator that failed the decoding process to be displayed on the display device. Code reader system.
3. In the code reader system according to claim 1, The code reader is a code reader that images a code attached to the bottom surface of the workpiece through the gap between the conveyor elements of the conveyor, The aforementioned camera is an area camera that generates an image in which multiple pixels are arranged in two dimensions. The synthesis processing unit synthesizes partial images consisting of a part of each of the multiple images and multiple rows. Code reader system.
4. In the code reader system according to claim 1, The aforementioned arithmetic unit, Based on the size of the composite image, the sizes of the multiple images, the conveying speed of the conveyor, and the installation conditions of the code reader, the expected number of images required to generate the composite image is calculated. The actual number of images used to generate the aforementioned composite image is counted. The index is calculated based on the difference between the expected number of sheets and the actual number of sheets. Code reader system.
5. In the code reader system according to claim 4, The calculation unit calculates the index that indicates whether the actual number of sheets is greater than or less than the expected number of sheets. Code reader system.
6. In the code reader system according to claim 4, The calculation unit adjusts the expected number of sheets in real time based on at least one of the encoder information and the predicted transport speed. Code reader system.
7. In the code reader system according to claim 1, The synthesis processing unit determines the overlap width of the multiple images in the conveying direction of the conveyor based on the size of the synthesized image, the sizes of the multiple images, the conveying speed of the conveyor, and the installation conditions of the code reader. Code reader system.
8. In the code reader system according to claim 7, The overlap width is provided with at least one of a predetermined lower limit and upper limit. Code reader system.
9. In the code reader system according to claim 1, Each of the aforementioned multiple images includes a fixed pattern that is captured regardless of time changes. The management device, when the indicator is below a predetermined value, causes the display device to display a message recommending the removal of the fixed pattern. Code reader system.
10. In the code reader system according to claim 9, The message prompts the user to mask the fixed pattern or to change the installation of the code reader so that the fixed pattern is not included. Code reader system.
11. In the code reader system according to claim 9, The aforementioned fixing pattern includes any of the following: conveyor components, ceiling lighting, ceiling patterns, lighting for the opposite code reader, or a frame for mounting the code reader. Code reader system.
12. In the code reader system according to claim 1, The management device displays a setting screen on the display device for determining the usage range to be used for actual imaging within the field of view of the code reader. Code reader system.
13. In the code reader system according to claim 1, The management device causes the display device to display a setting screen for determining invalid areas in the code reader's field of view that are not to be used as image features. Code reader system.
14. A code reader that reads the code attached to a workpiece being transported on a conveyor belt, A management device connected to the code reader and display device, which displays the information from the code reader on the display device, A method using a code reader system comprising: The process involves taking multiple images of the workpiece using the camera of the code reader, The code reader's synthesis processing unit performs a synthesis process on the plurality of images based on the image features of each of the plurality of images to generate a composite image. The code reader's decoding processing unit performs a decoding process on the composite image, The calculation unit of the code reader calculates an index indicating the accuracy of the synthesis process of the multiple images, The output unit of the code reader outputs the result of the decoding process and the indicator to the management device. The management device performs the step of displaying the index calculated for the composite image that failed the decoding process on the display device, A method for providing this.