Barcode detection system, barcode detection method, and barcode detection program

Abstract

To provide a bar code detection system, a method for detecting a bar code, and a bar code detection program which can precisely recognize bar codes BC on a plurality of packages Ba of a package group BS if the bar codes are divided on more than one surface and also can calculate a height of each bar code from a cradle.SOLUTION: A bar code detection system 100 includes: a workpiece position calculation unit 12 for calculating a position of a package group BS along a conveyance direction CD made of a plurality of packages Ba put on a pallet PL; a code reading unit 30 for imaging the package group BS when the package group is being conveyed without stopping the conveyance, reading at least one bar code BC, and outputting code coordinate information 55 of each bar code BC; and a code calculation unit 13 for calculating a height of each bar code BC from a pallet PL on the basis of a relative positional information of the package group BS and the code reading unit 30 and the code coordinate information 55.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a barcode detection system, a barcode detection method, and a barcode detection program that can simultaneously recognize barcodes on multiple sides of a group of packages and calculate the height of each barcode from a stand. [Background technology]

[0002] Patent Document 1 discloses a method of automating barcode scanning by installing multiple code readers on a conveyor line.

[0003] Patent Document 2 discloses a method for simultaneously reading a plurality of barcodes with a single code reader using a digital camera.

[0004] Patent Document 3 discloses a method for improving reading accuracy by simultaneously capturing images of three oblique faces of a rectangular parallelepiped on which a barcode is printed, and correcting distortion of the barcode shape from the vertices and edges of the rectangular parallelepiped.

[0005] Patent Document 4 discloses a method for recognizing a barcode by simultaneously capturing images of five faces of a rectangular parallelepiped on which the barcode is printed using mirrors.

[0006] Patent Document 5 discloses a method for automatically detecting the case type and number of cases by measuring the cargo height and the surface area of ​​the top cargo with a distance sensor, detecting the barcode of the cargo with a code reader that moves up and down. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 8-178620 [Patent Document 2] Japanese Patent Application Publication No. 9-114913 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-148786 [Patent Document 4] Japanese Patent Application Publication No. 7-21300 [Patent Document 5] Patent Publication No. 2021-59438 Summary of the Invention [Problem to be solved by the invention]

[0008] Generally, to read barcodes printed on cases during transport, a code reader is placed on the side in the transport direction, and detection is performed only at a specific height (for example, only the bottom and top cases).

[0009] For barcodes printed at various heights on the side surface in the conveying direction, there are methods such as using multiple code readers as in Patent Document 1, or moving a code reader up and down as in Patent Document 5. However, even these methods cannot recognize barcodes printed on other surfaces, such as the front and rear surfaces in the conveying direction.

[0010] To recognize barcodes on multiple sides, there are methods such as installing a camera at an angle to simultaneously capture images of three sides as in Patent Document 3, and using a mirror to simultaneously capture images of the entire surface as in Patent Document 4. However, it is not possible to obtain height information for the detected barcode, and it is not possible to determine which case has been recognized when multiple cases are stacked.

[0011] To provide a barcode detection system, a barcode detection method, and a barcode detection program that can accurately recognize the barcodes of multiple packages included in a package group even if the barcodes are displayed separately on multiple surfaces such as the front and side, and can calculate the height of each package from a stand without stopping the transport. [Means for solving the problem]

[0012] The barcode detection system of the present invention comprises a work position calculation unit that calculates the position along the conveying direction of a group of luggage consisting of multiple luggage placed on a platform; a code reading unit that photographs the group of luggage without stopping the transport while it is being transported, recognizes one or more barcodes, and outputs image coordinate information for each of the barcodes; and a code height calculation unit that calculates the height of each of the barcodes from the platform based on the relative positional relationship between the group of luggage and the code reading unit and the image coordinate information.

[0013] The barcode detection method of the present invention includes a work position calculation step for calculating the position along the conveying direction of a group of luggage consisting of multiple luggage placed on a platform; a code reading step for photographing the group of luggage without stopping the transport while it is being transported, recognizing one or more barcodes, and outputting image coordinate information for each of the barcodes; and a code height calculation step for calculating the height of each of the barcodes from the platform based on the relative positional relationship between the group of luggage and the code reading unit and each of the image coordinate information.

[0014] The barcode detection program of the present invention includes a work position calculation step for calculating the position along the conveying direction of a group of packages consisting of multiple packages placed on a platform; a code reading step for photographing the group of packages without stopping the transport while the group of packages is being transported, recognizing one or more barcodes, and outputting image coordinate information for each of the barcodes; and a code height calculation step for calculating the height of each of the barcodes from the platform based on the relative positional relationship between the group of packages and the code reading unit and each of the image coordinate information. [Effects of the Invention]

[0015] According to the present invention, even if the barcodes of multiple packages included in a package group are separated into multiple faces such as the front and side, these can be accurately recognized and their respective heights from the platform can be calculated.Furthermore, information regarding the number of packages included in the package group can be calculated with high accuracy. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a barcode detection system 100 according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing a schematic configuration of a barcode detection system 100. FIG. [Figure 3A] 1 is a first half of a flowchart showing an outline of the operation of the barcode detection system 100. [Figure 3B] This is the second half of the flowchart. [Figure 4A] 10 is a plan view showing the relative positional relationship between the group of packages BS and the code reading unit 30 in order to determine whether the read barcode BC is on the front or side of the group of packages BS. [Figure 4B] FIG. 4B is an explanatory diagram showing a group of packages BS in an image corresponding to FIG. 4A. [Figure 5] This is an explanatory diagram showing line drawings showing the approaching state of a group of luggage BS in each image taken five times consecutively while the group of luggage BS is being transported without stopping the transport, arranged in order from right to left. [Figure 6A] 10 is a plan view showing the relative positional relationship between the group of packages BS and the code reading unit 30 when the read barcode BC is on the side (left side) of the group of packages BS. [Figure 6B] FIG. 6B is an explanatory diagram showing a group of packages BS in an image corresponding to FIG. 6A. [Figure 7A] 10 is a plan view showing the relative positional relationship between a group of packages BS and the code reading unit 30 when the read barcode BC is in front of the group of packages BS. [Figure 7B] FIG. 7B is an explanatory diagram showing a group of packages BS in an image corresponding to FIG. 7A. [Figure 8A] 10 is a graph in which the code coordinate information 55 of each barcode BC read by the code reading unit 30 multiple times during the conveyance of the group of packages BS without stopping the conveyance is plotted in the image coordinate system. [Figure 8B] This is a graph in which the vertical coordinates of the code coordinate information 55 plotted in FIG. 8A are converted into actual heights by performing code height correction and then plotting the data. [Figure 9]The graph shows the code coordinate information 55 of each barcode BC read multiple times by the code reading unit 30, divided into barcode readers 30a and 30b, and plotted before and after code height correction. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated. In the embodiment of the present invention, the X-axis, Y-axis, and Z-axis are mutually orthogonal, the X-axis and Y-axis are parallel to the horizontal direction, and the Z-axis is parallel to the vertical direction.

[0018] 1. Basic Configuration and Operation of Barcode Detection System 100 First, the basic configuration and basic operation of a barcode detection system 100 according to an embodiment of the present invention will be described with reference to FIGS.

[0019] This barcode detection system 100 detects each barcode BC of a plurality of packages Ba constituting a package group BS that is placed on a pallet PL (corresponding to a "stand" in this invention) and transported. The package group BS is transported on a conveyor Cv in a transport direction CD.

[0020] The conveyor Cv is an example of a device that transports pallets PL. More specifically, the conveyor Cv may be a roller conveyor, a belt conveyor, a chain conveyor, or a gravity conveyor. However, the conveyor Cv is not limited to the conveyor Cv, and a transport cart or the like may be used instead.

[0021] The package Ba has a substantially rectangular parallelepiped shape (including a substantially cubic shape), and includes, for example, a box-shaped packaging material and an item contained in the packaging material. Specific examples of packaging materials include, but are not limited to, cardboard boxes.

[0022] Each piece of luggage Ba is affixed with a barcode BC. An example of the barcode BC is ITF (Interleaved Two of Five). ITF is a barcode developed by Intermec, Inc., and is mainly printed on cardboard boxes and used as a logistics product code. However, the barcode BC is not limited to ITF.

[0023] The barcode BC is attached to a predetermined position on the package Ba, such as a position on the side of the package Ba where the distance between the bottom edge of the package Ba and the barcode BC is 32 mm±3 mm and the distance between the end of the side of the package Ba in the substantially vertical direction and the barcode BC is 19 mm or more.

[0024] However, in a group of packages BS where multiple packages Ba are stacked in multiple tiers lined up in the left-right and depth directions, it is not always the case that all of the barcodes BC of each package Ba are aligned on a specific surface (e.g., a side) of the group of packages BS. For example, even if the barcodes BC of each package Ba in most of the tiers are aligned on the side, the barcodes BC of each package Ba in the remaining tiers may be aligned on the front (front). Alternatively, there may be a mixture of tiers where the barcodes BC of each package Ba are aligned on the side and tiers where the barcodes BC of each package Ba are aligned on the front.

[0025] The barcode detection system 100 is configured to be able to accurately recognize the barcodes BC of each package Ba in a package group BS even if the barcodes BC are not all on the same surface.

[0026] 1.1 Basic Configuration of Barcode Detection System 100 Fig. 1 is a perspective view showing a barcode detection system 100 according to one embodiment of the present invention. Fig. 2 is a block diagram showing a schematic configuration of the barcode detection system 100. Note that part of the barcode detection system 100 is not shown in Fig. 1.

[0027] As shown in these figures, the barcode detection system 100 includes an inspection device 1, a distance measuring unit 20, a code reading unit 30, a work detection unit 40, and a display unit 60.

[0028] The inspection device 1 detects each barcode BC of the multiple packages Ba that make up the package group BS. When a single type of package Ba is loaded according to one of the predetermined pallet loading patterns, it is possible to accurately calculate information regarding the number of the multiple packages Ba, similar to the invention disclosed in Patent Document 5. However, detailed explanation of the calculation method will be omitted below.

[0029] The inspection device 1 includes a control unit 10 and a memory unit 50. The memory unit 50 includes a storage device and stores computer programs such as software and data. Specifically, the memory unit 50 includes a main storage device such as a semiconductor memory, and an auxiliary storage device such as a semiconductor memory, a solid-state drive, and / or a hard disk drive. The memory unit 50 may include removable media. The memory unit 50 is an example of a storage medium (e.g., a non-transitory computer-readable storage medium).

[0030] The control unit 10 includes a processor such as a CPU (Central Processing Unit). The processor of the control unit 10 executes computer programs stored in the storage device of the memory unit 50, and functions as a packaging style calculation unit 11, a work position calculation unit 12, a cord height calculation unit 13, an extraction unit 14, a comparison unit 15, and a judgment unit 16. In other words, the control unit 10 includes the packaging style calculation unit 11, the work position calculation unit 12, the cord height calculation unit 13, the extraction unit 14, the comparison unit 15, and the judgment unit 16. The packaging style calculation unit 11, the work position calculation unit 12, and the cord height calculation unit 13 will be described later. The processor is an example of a "computer."

[0031] The storage unit 50 stores code identification information 51 for various packages Ba that are expected to be transported, as well as size information 52 and quantity information 53 associated with the code identification information 51. The size information 52 includes height information 52a, width information 52b, and depth information 52c.

[0032] The distance measuring unit 20 measures the distance between the target object and the distance measuring unit 20. Since the height of the installation position of the distance measuring unit 20 from the pallet PL is known, the height of the top surface BSf of the package group BS from the pallet PL can be calculated based on the measured distance. Note that if the height of the installation position from the conveyor Cv is known, it can be converted to the height from the pallet PL by subtracting the thickness of the pallet PL.

[0033] The distance measurement unit 20 is, for example, a distance measurement sensor. The distance measurement sensor measures the distance and angle between the object and the distance measurement unit 20 using, for example, light or ultrasonic waves. Specifically, the distance between the object and the distance measurement unit 20 is continuously acquired while changing the measurement angle (direction). The distance measurement sensor using light is, for example, a LiDAR (Light Detection and Ranging) sensor.

[0034] A LiDAR sensor measures the distance between an object and the LiDAR sensor by, for example, emitting light (e.g., laser light) and receiving the light reflected by the object. Therefore, a LiDAR sensor includes at least a light source (e.g., laser light source) and a light receiving element. The LiDAR sensor emits, for example, visible light or infrared light.

[0035] The LiDAR sensor is, for example, a scanning type. The scanning type may be either a movable type or a non-movable type. The movable type, for example, uses a motor to rotate a mirror to change the light emission direction (mechanical rotation type). The movable type, for example, uses a microelectromechanical system (MEMS) to rotate a mirror to change the light emission direction (solid-state type). The non-movable type changes the light emission direction by changing the light path using, for example, liquid crystal, electro-optical crystal, or silicon photonics. The non-scanning type emits a strong flash of light spread over a wide angle and measures multiple points simultaneously using, for example, a complementary metal-oxide semiconductor (CMOS) image sensor. The type of the distance measurement unit 20 is not particularly limited as long as it can measure the distance and angle between the target object and the distance measurement unit 20.

[0036] In this embodiment, the distance measurement unit 20 is described as a scanning LiDAR sensor. Note that the measurement of the distance and angle to an object by the distance measurement unit 20 may be referred to as "scanning." In other words, the distance measurement unit 20 scans along a scanning direction SD that is perpendicular to the conveyance direction CD.

[0037] The code reading unit 30 photographs the group of packages BS while it is being transported without stopping the transport, analyzes the photographed data to recognize one or more barcodes BC contained therein, and outputs the identification information and image coordinate information (unit: pixel) of each recognized barcode BC. These are stored in the memory unit 50 as code identification result information 54 and code coordinate information 55. Note that photographing the group of packages BS during transport can be performed once, multiple times, or continuously at a predetermined timing as needed.

[0038] In this embodiment, the code reading unit 30 is composed of two barcode readers 30a and 30b capable of reading at least ITF. These are arranged one above the other so that at least a portion of the imaging ranges R30a and R30b of each barcode reader overlap. However, the number of barcode readers is not limited to two, and they do not necessarily have to be arranged one above the other. Multiple barcode readers may be arranged so that at least a portion of the imaging ranges of adjacent barcode readers overlap. Furthermore, the code reading unit 30 is arranged to capture an image of the package group BS from an oblique direction relative to the conveying direction CD of the package group BS. This arrangement allows one or more barcodes BC on the front and one side of the package group BS to be simultaneously recognized.

[0039] The workpiece detection unit 40 detects that a group of packages BS as workpieces (target objects) has passed a predetermined position while being transported along the transport direction CD. An example of the workpiece detection unit 40 is a transmission-type photoelectric sensor in which a light emitter and a light receiver are arranged opposite each other and which detects when the detection light emitted from the light emitter is blocked by an object. However, the workpiece detection unit 40 is not limited to a transmission-type photoelectric sensor, and any sensor that can detect with high accuracy that the group of packages BS has passed a predetermined position while being transported can be used instead.

[0040] The group of packages BS is transported in the transport direction CD at a constant transport speed v. Therefore, the current position of the group of packages BS can be calculated from the elapsed time t from the time when the work detection unit 40 detects that the group of packages BS has passed a predetermined position.

[0041] In this embodiment, the light-emitter 40a and light-receiver 40b of the transmission-type photoelectric sensor are disposed near both ends of the conveyor Cv at a height where the detection light is perpendicular to the conveying direction CD and is blocked by the group of packages BS. This makes it possible to detect the moment when the front part (edge ​​when viewed from the side) of the group of packages BS is blocked by the detection light as it is conveyed.

[0042] The display unit 60 is a display device that displays various information, and may be, for example, a display such as a liquid crystal display, but is not limited to this.

[0043] 1.2 Basic Operation of Barcode Detection System 100 FIG. 3A is the first half of a flowchart showing the general operation of the barcode detection system 100, and FIG. 3B is the second half of the flowchart.

[0044] First, as shown in FIG. 3A, in step S301, the distance measuring unit 20 measures the distance to the top surface BSf of the luggage group BS while scanning along the scanning direction SD, and calculates the height of the top surface BSf from the pallet PL by detecting the contours of the top surface BSf and pinholes (presence or absence, their position and shape) from the measured distance and angle.

[0045] In step S302, the package style calculation unit 11 calculates the area of ​​the upper surface BSf of the package group BS. The package style calculation unit 11 also calculates the left edge position of the upper surface BSf of the package group BS based on the above outline, and calculates the conveyance position deviation amount f from the result. This conveyance position deviation amount f will be described later with reference to FIG. 6A.

[0046] In step S303, the workpiece detection unit 40 detects that the group of packages BS has passed a predetermined position while being conveyed along the conveying direction CD.

[0047] In step S304, the workpiece position calculation unit 12 calculates the current position of the group of packages BS from the time that has elapsed since the workpiece detection unit 40 detected that the group of packages BS has passed through a predetermined position.

[0048] In step S305, the code reading unit 30 reads each barcode BC of the plurality of packages Ba in the package group BS, and obtains the code identification result information 54 and the code coordinate information 55 for each package.

[0049] In step S306, the code height calculation unit 13 determines which side of the package group BS the barcode is on, based on the relative positional relationship between the current position of the package group BS and the code reading unit 30, and the horizontal component of the code coordinate information 55 of each barcode BC, and then calculates the code height. For example, it determines whether the barcode is on the front or side of the package group BS, and corrects the code height according to the determination result. Details of this will be described later.

[0050] In step S307, it is determined whether reading of each barcode BC of the multiple packages Ba has been completed. If Yes, the process proceeds to the latter half of the flowchart in FIG. 3B, and if No, the process returns to step S304.

[0051] Next, as shown in FIG. 3B, in step S311, the packaging style calculation unit 11 acquires the size information 52 and the number information 53.

[0052] In step S312, the packaging style calculation unit 11 calculates the number of layers of the package group BS.

[0053] In step S313, the packaging style calculation unit 11 calculates the number of packages Ba located at the top of the package group BS.

[0054] In step S314, the package style calculation unit 11 calculates the number of packages Ba in the package group BS.

[0055] In step S315, the package style calculation unit 11 calculates the heights of the uppermost and lowermost packages Ba of the package group BS.

[0056] In step S316, the extraction unit 14 extracts the code identification result information 54 of the top and bottom packages Ba from the code height obtained from the code height calculation unit 13 and the package height obtained from the package style calculation unit 11.

[0057] In step S317, the comparison unit 15 compares the code identification result information 54 of the uppermost package Ba extracted by the extraction unit 14 with the code identification result information 54 of the lowermost package Ba.

[0058] 2. Height Correction Calculation of Barcode BC in Barcode Detection System 100 2.1 How to distinguish between the front and side of a group of luggage Fig. 4A is a plan view showing the relative positional relationship between the group of packages BS and the code reading unit 30, in order to determine whether the read barcode BC is on the front or side of the group of packages BS. Fig. 4B is an explanatory diagram showing the group of packages BS in an image corresponding to Fig. 4A. Fig. 5 is an explanatory diagram showing line drawings showing the approaching state of the group of packages BS in each image taken five times consecutively without stopping the transport of the group of packages BS, arranged in order from right to left. The code reading unit 30 is disposed diagonally forward right with respect to the transport direction CD, and is able to recognize the barcodes BC on the front and left side of the group of packages BS.

[0059] As can be seen from Figure 5, as the group of packages BS approaches along the conveying direction CD, the group of packages BS gradually becomes larger in the image read by the code reading unit 30. Also, the intersection line between the front and left side of the group of packages BS (hereinafter also referred to as the "edge"; indicated by an arrow at the bottom of each photograph) appears from the right edge of the image and gradually moves to the left. In other words, the left side of this edge position is the front of the group of packages BS, and the right side is the left side of the group of packages BS.

[0060] The basic idea for calculating the edge position in an image is as follows. (1) The workpiece detector 40 detects the time (starting point of time) when the group of packages BS passes a predetermined position, and tracks the edge position based on the elapsed time (time stamp) thereafter. (2) The barcode BC located to the right of the edge position calculated from the timestamp in the image is determined to be the left side of the luggage group BS, and the barcode BC located to the left of the edge position is determined to be the front.

[0061] As shown in FIGS. 4A and 4B, the amount of progress a of the edge position after the baggage group BS passes through the predetermined position is expressed as follows, where v is the conveying speed of the baggage group BS and t is the elapsed time: a=v t (1)

[0062] The field of view width y in this case is y= c -a·cosθ·(cb) / L ···(2)

[0063] The apparent progression of the edge position on the field of view is g g=a·sinθ-a·cosθ·(cb) / 2L···(3)

[0064] The calculation results up to this point are in mm, so convert them to pixels in the image coordinate information. If the edge position from the opposite side of the origin is X pixels, then X = (ε / y) g (4)

[0065] The edge position (pixel) is calculated by substituting the formulas (1) to (3) into the formula (4).

[0066] The calculated edge position is compared with the horizontal component (x coordinate) of the code coordinate information 55 of the barcode BC to determine whether the barcode BC is on the front or side, and the barcode height is corrected according to the result of this determination.

[0067] 2.2 Correcting the height of the barcode on the side of the baggage group BS Fig. 6A is a plan view showing the relative positional relationship between the group of packages BS and the code reading unit 30 when the read barcode BC is on the side (left side) of the group of packages BS. Fig. 6B is an explanatory diagram showing the group of packages BS in the image corresponding to Fig. 6A.

[0068] The basic idea is as follows: (1) When the group of packages BS approaches along the conveying direction CD, the group of packages BS approaches in the field of view of the code reading unit 30. (2) When the luggage group BS approaches, the center of the field of view (vertical direction) does not move, but the upper half of the field of view rises and the lower half of the field of view falls.

[0069] First, consider the case where there is no conveying position deviation amount f. Consider the relationship between the amount of work progress and the distance it moves away. The inclination of the code reading unit 30 relative to the workpiece travel direction is defined as θ. If the inclination of the field of view relative to the workpiece travel direction is α, α=90°-θ

[0070] If the amount of work progress is a, the distance it moves away is d. d=a·sinα=a·sin(90°-θ)=a·cosθ

[0071] Let y be the field of view width when the workpiece is moved d away. If the depth is L, the minimum field of view width is b, and the maximum field of view width is c, y=d·(cb) / L+b =a·cosθ·(cb) / L+b

[0072] Here, consider the actual progress amount a at the xth pixel. Let g be the apparent amount of progress on the visual field width y. g=a·cosα+d·(cb) / 2L =a·sinθ+a·cosθ·(cb) / 2L

[0073] Let the total number of pixels in the x direction be ε. x / ε=g / y =(a·sinθ+a·cosθ·(cb) / 2L) / (a·cosθ(cb) / L+b)

[0074] Next, consider the case where there is a conveying position deviation amount f. The conveyance deviation value is added to the calculation formula when there is no conveyance position deviation. The inclination of the code reading unit 30 relative to the workpiece travel direction is defined as θ. If the inclination of the field of view relative to the workpiece travel direction is α, α=90°-θ

[0075] If the amount of work advancement is a and the amount of misalignment of the transport position is f, the distance d that moves away is d=a·sinα+p =a·sin(90°-θ)+f· sinθ = a cosθ+f sinθ

[0076] Let y be the field of view width when the workpiece is moved d away. If the depth is L, the minimum field of view width is b, and the maximum field of view width is c, y=d·(cb) / L+b = (a·cosθ+f·sinθ) (cb) / L+b

[0077] Here, consider the actual progress amount a at the xth pixel. Let g be the apparent amount of progress on the visual field width y. g=a·cosα-f·sin (90°-θ) +d·(cb) / 2L = a sinθ-f cosθ + (a·cosθ+f·sinθ) (cb) / 2L

[0078] Let the total number of pixels in the x direction be ε. x / ε=g / y =( a sinθ-f cosθ + (a·cosθ+f·sinθ) (cb) / 2L) / ( (a cosθ + f sinθ) (cb) / L+b)

[0079] Transform the formula into the form a=. a=(f·( sinθ ·(cb) / 2L- cosθ - sinθ ·(x / ε)·(cb) / L)-b·(x / ε)) / (cosθ·(x / ε)·(cb) / L -sinθ-cosθ·(cb) / 2L)···(5)

[0080] <Height correction calculation> If the rate of decline when d moves away is e, e=b / y=b / (d·(cb) / L+b)

[0081] Add d= to this a cosθ+f sinθ Substitute. e=b / ( (a·cosθ+f·sinθ)(cb) / L+b) (6)

[0082] The ratio is the same in both the x and z directions. Substituting equation (5) into equation (6) gives the fall rate (rise rate) e at x pixels.

[0083] Use e to calculate the actual value. If the corrected height is Z (pixels) and the height obtained from the code reader 30 is z (pixels), then Z=(σ / 2)-(σ / 2-z) / e

[0084] 2.3 Correcting the height of the barcode on the front of the baggage group BS Fig. 7A is a plan view showing the relative positional relationship between the group of packages BS and the code reading unit 30 when the read barcode BC is in front of the group of packages BS. Fig. 7B is an explanatory diagram showing the group of packages BS in the image corresponding to Fig. 7A.

[0085] The basic idea is as follows: (1) Assume that the cargo group BS is moving in a virtual direction perpendicular to the actual direction of travel. (2) A position that is a distance D away from the code reader 30 in the actual traveling direction For the reference surface (Front end face of luggage group BS) Calculate how far away it is and substitute it into the side calculation logic. (3) The position of the reference plane is The reference plane has passed the specified position. is detected by a sensor and calculated from the timestamp and the conveying speed v.

[0086] Transport reference at the first sensor detection position distance H is H=D·tan(90°-θ+ω / 2) Here, the transport reference distance H indicates the distance in the actual travel direction from the travel reference plane to the code reading unit 30 at the time when the travel reference plane passes a predetermined position.

[0087] Progress reference plane The movement is calculated from the timestamp. The time elapsed from the time when the luggage group BS passed the predetermined position is defined as t, and the transport speed is defined as v. If the distance (transport position) from the code reading unit 30 to the side of the baggage group BS in the virtual traveling direction is D, the transport reference distance H and the distance D are The difference h is expressed by the following equation: h=D·tan(90°-θ+ω / 2)-Dt·v···(7) Here, equation (7) shows how much the travel reference plane is displaced from a position that is the same distance away from the code reading unit 30 as the transport position D when examining the side surface, when the elapsed time is t.

[0088] therefore, This h is calculated as equivalent to the conveying position deviation f when examining the side surface. Consider the formula for side consideration. Since the reference point is different from when examining the side, if the value corrected in the x direction is set as X, X=ε-x (8)

[0089] Replace x with X in the side-examination formula. X / ε=( a sinθ-f cosθ + (a·cosθ+f·sinθ) (cb) / 2L) / ( (a cosθ + f sinθ) (cb) / L+b)

[0090] Here, the conveying position deviation amount f Difference Replace with h. X / ε=(a·sinθ-h·cosθ +(a·cosθ+h·sinθ)·(cb) / 2L) / ((a·cosθ+h·sinθ)·(cb) / L+b)

[0091] Transform the formula into the form a=. a=(h·(sinθ·(cb) / 2L-cosθ -sinθ·( X / ε)·(cb) / L)-b·( X / ε)) / (cosθ·( X / ε)·(cb) / L -sinθ-cosθ·(cb) / 2L)···(9)

[0092] <Height correction calculation> Replace f with h in the height correction calculation formula for sides. e=b / ( (a·cosθ+f·sinθ) (cb) / L+b) e=b / ( (a·cosθ+h·sinθ) (cb) / L+b) (10)

[0093] Substituting equations (7) to (9) into equation (10) gives the decrease rate (increase rate) e at x pixels.

[0094] Use e to calculate the actual value. If the corrected height is Z (pixels) and the height obtained from BCR is z (pixels), Z=(σ / 2)-(σ / 2-z) / e

[0095] By performing such height correction calculation, the same effect as in the case of the barcode BC on the side of the package group BS can be achieved.

[0096] <Effect of barcode BC height correction by barcode detection system 100> Fig. 8A is a graph in which the code coordinate information 55 of each barcode BC read multiple times by the code reading unit 30 while the group of packages BS is being transported without stopping the transport is plotted on an image coordinate system. Fig. 8B is a graph in which the vertical coordinate of the code coordinate information 55 plotted in Fig. 8A is converted to actual height by performing code height correction on the code coordinate information 55. Fig. 9 is a graph in which the code coordinate information 55 of each barcode BC read multiple times by the code reading unit 30 is divided into barcode readers 30a and 30b, and the data before and after code height correction are plotted.

[0097] As can be seen from these figures, in the image coordinate system, when the package group BS is transported along the transport direction CD, the vertical component of the code coordinate information 55 of the barcode BC read by the code reading unit 30 fluctuates significantly. In contrast, the value after code height correction hardly fluctuates, and it can be seen that it generally accurately indicates the actual height of the barcode BC.

[0098] As described above, by correcting the barcode height, it is possible to continuously obtain barcode height information for cases during movement.

[0099] If the barcode is stopped at a specific position, it is possible to obtain height information by measuring the barcode height at that position in advance, but compared to this case, not stopping the barcode reduces the takt time and improves productivity.

[0100] In addition, initial setup is easier as there is no need for advance measurements at each stop point, and continuous acquisition allows for an increased number of measurement points, which is expected to improve reliability. [Industrial Applicability]

[0101] The present invention can be used in fields such as systems for detecting various codes such as barcodes, detection methods, and detection programs. [Explanation of symbols]

[0102] 100 Barcode Detection System 1 Inspection equipment 10 Control Unit 11 Packaging Calculation Department 12 Work position calculation unit 13 Cord height calculation section 14 Extraction part 15 Comparison section 16 Judgment section 20 Ranging section 30 Code reader 30a Barcode reader 30b Barcode reader 40 Work detection unit 40a floodlight 40b receiver 50 Storage section 51 Code Identification Information 52 Size Information 52a Height Information 52b width information 52c Depth information 53 Quantity Information 54 Code Identification Result Information 55 Code coordinate information 60 Display

Claims

1. a work position calculation unit that calculates the edge position of the front end along the conveyance direction of a group of packages that is made up of a plurality of packages each having a substantially rectangular parallelepiped shape placed on a platform; a code reader that photographs the group of packages while they are being transported without stopping the transport, recognizes one or more barcodes, and outputs image coordinate information of each of the barcodes; a code height calculation unit that calculates the height of each of the barcodes from the platform based on the relative positional relationship between the edge position of the front end of the group of packages calculated by the work position calculation unit and the code reading unit and each of the image coordinate information; Equipped with The front of the group of parcels is perpendicular to the conveying direction, The code height calculation unit determines whether each barcode is displayed on the front or side of the group of luggage based on the relative positional relationship between the edge position of the front end of the group of luggage and the code reading unit and each image coordinate information, and calculates the height of each barcode from the platform according to each determination result.

2. The transport system further includes a workpiece detection unit that detects when the front end of the group of packages passes a predetermined position during transport, 2. The barcode detection system according to claim 1, wherein the work position calculation unit calculates the edge position of the front end of the group of packages based on the elapsed time since the front end of the group of packages passed the specified position and a predetermined conveying speed.

3. a distance measuring unit that measures the height of the upper surface of the group of packages from above by scanning in a scanning direction perpendicular to the conveying direction, The barcode detection system of claim 1 or claim 2, wherein the code height calculation unit calculates the height of each barcode from the platform based on the amount of deviation of the transport position from a reference position along the scanning direction of the side edge position of the top surface of the group of packages detected by the distance measurement unit.

4. 3. The barcode detection system according to claim 1, wherein the code reading unit is configured with a plurality of barcode readers arranged one above the other so that at least a portion of the imaging ranges of adjacent barcode readers overlap.

5. 3. The barcode detection system according to claim 1, wherein the code reader is disposed so as to photograph the group of packages from an oblique direction relative to the conveying direction.

6. a workpiece position calculation step of calculating a front edge position along a conveyance direction of a group of pieces of luggage made up of a plurality of pieces of luggage having a substantially rectangular parallelepiped shape placed on a stand; a code reading step of photographing the group of packages while they are being conveyed without stopping the conveyance, recognizing one or more barcodes, and outputting image coordinate information of each of the barcodes; a code height calculation step of calculating the height of each of the barcodes from the platform based on the relative positional relationship between the edge position of the front end of the group of packages and a code reading unit calculated in the work position calculation step and each of the image coordinate information; Including, The front of the group of parcels is perpendicular to the conveying direction, The code height calculation step determines whether each barcode is displayed on the front or side of the group of luggage based on the relative positional relationship between the edge position of the front end of the group of luggage and the code reading unit and each image coordinate information, and calculates the height of each barcode from the stand according to each determination result.

7. a workpiece position calculation step of calculating a front edge position along a conveyance direction of a group of pieces of luggage made up of a plurality of pieces of luggage having a substantially rectangular parallelepiped shape placed on a stand; a code reading step of photographing the group of packages while they are being conveyed without stopping the conveyance, recognizing one or more barcodes, and outputting image coordinate information of each of the barcodes; a code height calculation step of calculating the height of each of the barcodes from the platform based on the relative positional relationship between the edge position of the front end of the group of packages and a code reading unit calculated in the work position calculation step and each of the image coordinate information; Including, The front of the group of parcels is perpendicular to the conveying direction, The code height calculation step determines whether each barcode is displayed on the front or side of the group of luggage based on the relative positional relationship between the edge position of the front end of the group of luggage and the code reading unit and each image coordinate information, and calculates the height of each barcode from the stand according to each determination result.

Images