Shipping mark reading method and conveying system with shipping mark reading device
By acquiring and analyzing the initial image of the cargo in an automated production line, and calculating and adjusting the distance between the mark and the image acquisition device, the problem of clear mark image acquisition of the fixed-focus lens in the uncertain position is solved, and the reliable reading of mark information is achieved.
Patent Information
- Application Number
- CN202411787978.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-03-25
AI Technical Summary
In an automated production line, how to obtain clear mark images based on undefined position conveying products and fixed-focus lenses to realize the reading of mark information.
By acquiring the initial image of the cargo into the cargo, trying to extract the mark area, calculating the actual distance between the mark and the image acquisition device based on the imaging size or imaging position of the mark, controlling the relative movement of the mark or image acquisition device, so that the mark falls into the clear imaging range, and reacquisition of the image to read the mark information.
In a conveying system with limited accuracy, a clear image of the mark is obtained through a fixed-focus lens, ensuring reliable reading of mark information and reducing the need for high-precision control and positioning.
Smart Images
Figure CN119692374A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field, and in particular to a mark reading method and a conveying system with a mark reading device. Background Art
[0002] Taking photovoltaic module production as an example, in the intelligent manufacturing system, the packaging, internal storage and transportation of photovoltaic modules are all completed automatically. In order to ensure correct operation during the transfer between various processes, it is necessary to confirm the identity information of the photovoltaic modules and other products to be processed. Generally, marks will be posted on the outer packaging of the packaged products to facilitate machine and manual inspection. In addition, during the shipping process, multiple packages will be combined to improve the packing efficiency.
[0003] In order to confirm the packaging information, there is a need to collect and verify the transported products online during the transportation process. The mark information can be read by an image acquisition device to realize product information verification. Similarly, based on the consideration of reducing the investment in the production line, the image acquisition device can use a fixed-focus lens with a fixed depth of field, and a clear image of the mark can only be obtained within a specific object distance range.
[0004] In an automated production line, a conveyor line that is only used for product flow between different workstations does not require high-precision control and positioning to reduce the procurement and production costs of the conveyor line because it only needs to transport products. In addition, due to the product specifications and the diverse ways of placing them on the pallet, their relative positions on the pallet are not fixed.
[0005] Therefore, the problem is how to obtain a clear image of the mark based on the uncertain position of the conveyed product and the fixed-focus lens to achieve the purpose of reading the mark information. Summary of the invention
[0006] In order to obtain a clear image of a mark based on a fixed-focus lens in a conveying system with limited precision, the present application provides a mark reading method and a conveying system with a mark reading device.
[0007] The technical solution of the present invention provides a method for reading a mark, which obtains an initial image of a pallet of goods and attempts to extract a mark area in the initial image; After the mark area is successfully extracted, the actual distance between the mark and the image acquisition device is calculated based on the image size or image position of the mark, and then the relative movement of the mark or the image acquisition device is controlled based on the actual distance, so that the mark falls within the clear imaging range of the image acquisition device; After the mark falls into the clear imaging range of the image acquisition device, the setting parameters of the image acquisition device are kept unchanged, and the pallet of goods is re-imaged to read the information on the mark.
[0008] Preferably, the timing of acquiring the initial image of the palletized goods is performed periodically based on a preset time interval or is triggered instantly or with a delay based on a given input signal.
[0009] Preferably, when controlling the relative movement of the mark or the image acquisition device, the palletized goods are transported to the clear imaging range of the image acquisition device by controlling the conveyor line, or the palletized goods are determined to enter the clear imaging range of the image acquisition device by setting the conveying time interval according to the actual distance during the process of conveying the palletized goods on the conveyor line.
[0010] Preferably, after attempting to extract the mark region in the initial image, if the mark region cannot be extracted successfully, the process of obtaining the initial image of the palletized goods is repeated.
[0011] Preferably, In the process of repeatedly acquiring the initial image of the palletized goods, the timing of acquiring the initial image of the palletized goods is periodically performed based on a preset time interval or is triggered instantly or with a delay based on a given input signal.
[0012] Preferably, when the actual distance between the mark and the image acquisition device is calculated based on the image size or image position of the mark, the image size or image position of the invariant feature of the mark is used as the image size D, and the fixed value is determined based on the predetermined invariant feature. , then the actual distance H is .
[0013] Preferably, when controlling the relative movement of the mark or the image acquisition device, a shooting distance h for obtaining a clear image is preset, and when the actual distance H between the mark and the image acquisition device is inferred, the image acquisition device or the mark is controlled to move in a corresponding direction a distance Hh so that the palletized goods enter the clear imaging range of the image acquisition device.
[0014] The technical solution of the present invention provides a conveying system with a mark reading device, comprising: Conveyor lines drive the movement of palletized goods; An image acquisition device, used to acquire images of palletized goods; The control system controls the conveyor line and the image acquisition device to execute any of the above-mentioned mark reading methods.
[0015] Preferably, The image acquisition device is arranged to move up and down perpendicular to the conveying direction of the conveying line; Or, the image acquisition device is arranged to move left and right perpendicular to the conveying direction of the conveying line; Alternatively, the image acquisition device can flip 180 degrees along the conveying direction of the conveying line.
[0016] Preferably, two groups of image acquisition devices are provided, and the two groups of image acquisition devices are respectively directed to one end along the conveying direction of the conveying line to take pictures; Preferably, the image acquisition device can flip 180 degrees along the conveying direction of the conveying line.
[0017] The mark reading method of the present application realizes the preliminary positioning of the relative position of the palletized goods by capturing the preliminary image of the palletized goods, thereby guiding the control system to specifically control the conveyor line or the image acquisition device to make the palletized goods have the correct position to provide a clear image, thereby achieving the purpose of mark reading. Under limited objective conditions, it can realize the function of reliable mark reading by relying only on the basic functions of the high-performance conveyor line and image acquisition device instead of relying on the high-performance conveyor line and image acquisition device. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a schematic diagram of a conveying system with a mark reading device according to the present invention; Figure 2 is a schematic flow chart of a method for reading a mark according to the present invention; Figure 3 It is a schematic diagram of the overall process of the mark reading method of the present invention; Figure 4 is a schematic diagram of another embodiment of a conveying system with a mark reading device according to the present invention; Figure 5 FIG. 4 is a schematic diagram of another embodiment of a conveying system with a mark reading device according to the present invention.
[0019] In the figure: 1: Conveyor line; 2: Image acquisition device; 3: Cargo pallet; 4: Cargo packaging; 5: Palletized cargo; 6: Shipping mark; 7: Control system. DETAILED DESCRIPTION
[0020] The following is a detailed description of this patent type in conjunction with the accompanying drawings and specific embodiments. In this specification, the dimensions of the drawings do not represent the actual size ratios. The drawings are only used to reflect the relative position relationship and connection relationship between the components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.
[0021] Figure 1 Schematic diagram of the structure of a conveying system with a mark reading device. The conveying system with a mark reading device includes a conveying line 1 for driving a pallet of goods 5 to move and an image acquisition device 2 for acquiring an image of the pallet of goods 5 on the conveying line 1. Optionally, the pallet of goods 5 may be composed of a plurality of cargo packages 4, and may be further carried by a cargo pallet 3. Figure 2The figure is a flow chart of the mark reading method. First, the initial image of the palletized goods 5 is obtained by the image acquisition device 2, and the mark 6 area in the palletized goods 5 is tried to be extracted. When the mark 6 is successfully extracted, the actual distance between the mark 6 and the image acquisition device 2 is calculated based on the image size of the mark 6, and the operation of the conveyor line 1 is controlled based on the relative distance, and the image of the palletized goods 5 is re-acquired at an appropriate time to read the mark information in the palletized goods 5.
[0022] Specifically, first obtain a first image of the palletized goods 5 and the conveyor line 1. The timing of obtaining the initial image is not limited, and the image acquisition device 2 can be triggered at a certain time interval or by a trigger instruction given by the control system to take a photo to obtain the initial image.
[0023] After acquiring the initial image of the palletized goods 5, an attempt is made to extract the area where the mark 6 is located from the image of the palletized goods 5. If the mark area is successfully extracted, the imaging size D or imaging position of the mark 6 is measured and the actual distance H between the palletized goods 5 and the image acquisition device 2 is inferred accordingly. When the image acquisition device 2 has a fixed-focus lens, the object distance h for obtaining a clear image is determined within a certain depth of field. Therefore, the relative movement distance Hh required between the palletized goods 5 and the image acquisition device 2 can be determined. Therefore, the distance between the palletized goods 5 and the image acquisition device 2 is adjusted to within the object distance range for obtaining a clear image. Then, the image acquisition device 2 reacquires the image of the palletized goods 5 to obtain a clear image, in which the mark area is re-extracted, and the mark information is read to obtain the specific information of the corresponding cargo packaging 4, such as product type, specification, and quantity.
[0024] Generally, the signal that triggers the area for acquiring the initial image comes from the upper control system 7. It can be directly or delayed triggered based on a certain input signal, or repeated at a certain time period. The image acquisition device 2 may acquire the initial image based on the material receiving signal after a certain length of delay. At this time, the palletized goods 5 have been transported on the conveyor line 1 for a distance and come near the image acquisition device 2. However, due to the insufficient operation accuracy of the conveyor line 1 and the large position error near the image acquisition device 2, the image acquisition device 2 can only determine a relatively blurred image of the palletized goods 5, which is not enough to realize the reading of the mark 6 information. The image acquisition device 2 can be triggered based on a specific signal, such as being triggered by the arrival of the cargo pallet 3 at a predetermined position. Figure 1For example, when the cargo packages 4 are arranged on the cargo pallet 3, their positions on the cargo pallet 3 are not specific due to the placement position, cargo specifications, etc. Therefore, even if the cargo pallet 3 reaches the preset position on the conveyor line 1, the distance between the mark 6 and the image acquisition device 2 cannot be guaranteed to be specific, so it is necessary to reposition and take pictures. Finally, the control system 7 can set a reasonable time interval according to the movement speed of the conveyor line 1 so that the image acquisition device 2 periodically and repeatedly acquires the image of the palletized cargo 5 at a certain time interval when the mark 6 is not detected until the presence of the mark 6 is detected. Figure 3 As shown, after reading the mark 6, the control system 7 controls the image acquisition device 2 and the conveyor line 1 to repeat the next round of detection operation.
[0025] like Figure 3 As shown, in the process of trying to extract the area where the mark 6 is located from the image of the pallet 5, there are two situations that need to be handled. If the area of the mark 6 can be successfully extracted from the image of the pallet 5, it is obvious that the movement mode of the conveyor line 1 or the image acquisition device 2 can be determined so that the image acquisition device 2 and the mark 6 reach a suitable relative distance. If the area of the mark 6 cannot be extracted from the image of the pallet 5, it is obvious that the initial image of the pallet 5 needs to be continuously acquired. The repeated cycle is controlled by the control system 7, and its specific mode should not be limited to the mode clearly described above.
[0026] When a fixed-focus lens is used, since the parameters of the lens are fixed, there is a certain implicit correlation between the images obtained in any form. In other words, the real distance between the mark 6 and the image acquisition device 2 can always be inferred based on the imaging situation. One way is to make a reasonable estimate based on the image size of the mark 6. That is, the product of the image size D of the mark 6 and the actual distance H between it and the image acquisition device 2 can be determined in theory to be a certain value, which can be determined in advance and is set as , which is related to the lens parameters and the actual size corresponding to the imaging size D of the mark 6. Thus, the actual relative distance between the mark 6 and the image acquisition device 2 can be obtained: It should be noted that the choice of imaging size D is arbitrary and does not need to be specifically limited, but it needs to be changed accordingly. In practical application, the mark 6 is a rectangular area, and the length, width or diagonal size of the mark 6 after imaging can be selected, which can be clearly distinguished and extracted in the imaging, and the fixed value can be determined accordingly. . For the case where the length or width of the mark 6 is used as the imaging dimension D, in a preferred solution, the average value of the length or width dimension in the image can be used as the imaging dimension D, rather than selecting one or several groups of position measurement data. In other solutions, the position information of the mark 6 in the imaging image can also be selected to infer the actual relative distance. The principle is the same as the process of using the imaging dimension of the mark 6. By determining the reflection of the distance between the mark 6 and the reference of the selected point on the graph as the imaging dimension D, as long as the actual distance between the mark 6 and the reference does not change during the movement of the mark 6, the distance H between the mark 6 and the image acquisition device 2 can always be estimated according to the same formula regardless of the position.
[0027] For the image acquisition device 2, the shooting distance (object distance) for obtaining a clear image is determined and is set to h. Therefore, after the actual distance H between the mark 6 and the image acquisition device 2 is inferred, it is only necessary to control the image acquisition device 2 or the mark 6 to move in a corresponding direction Hh, that is, the mark 6 is located within the object distance range for obtaining a clear image. Due to the existence of the depth of field of the lens, the relative distance between the image acquisition device 2 and the mark 6 for obtaining a clear image can float within a certain range above and below the object distance h, thereby giving the system a certain fault tolerance space. When the control system 7 controls the movement of the conveyor line 1 to make the mark 6 enter the clear imaging range of the image acquisition device 2. When the stroke is small, even if there is no feedback control, the distance tolerance of the conveyor line 1 is still acceptable, which can ensure that the mark 6 is within the clear imaging range, so it is reliable. Usually, the palletized goods 5 move toward the image acquisition device 2 from far to near, and the mark 6 is outside the clear imaging distance when the initial distance is collected for the first time. Then the palletized goods 5 continue to be transported, and the control system 7 only needs to trigger the second imaging of the image acquisition device 2 after a suitable time interval according to the movement speed of the conveyor line 1, so as to obtain a clear image of the mark 6. This process does not interfere with the operation of the conveyor line 1, and can be completely synchronized with the normal operation of the conveyor line 1 to transport products.
[0028] After re-obtaining a clear image of the palletized goods 5, the area where the mark 6 is located can be extracted, and only the image of the mark 6 is obtained, and the information in the mark 6 is extracted to achieve the purpose of verifying the palletized goods 5 or the goods packaging 4 therein. The information may be encoded and solidified in the mark 6 in the form of a barcode, a QR code, etc. Therefore, the process of extracting information can be achieved through existing image processing and barcode scanning technologies. It does not belong to the key content of the technical solution of this application.
[0029] Figure 1A structure of a conveying system with a mark reading device has been shown. The image acquisition device 2 can be set above the conveying line 1 to take pictures facing the incoming direction of the palletized goods 5. Based on the consideration of preventing the image acquisition device 2 from interfering with the movement of the palletized goods 5, the image acquisition device 2 is generally set to move, so as to move out of the passing area of the palletized goods 5 after obtaining the image when the palletized goods 5 pass by. The image acquisition device 2 can be set to move up and down. On the one hand, it avoids interfering with the palletized goods 5 by moving upward out of the passing area of the palletized goods 5. On the other hand, when the palletized goods 5 are stacked up and down, the image acquisition device 2 is moved up and down to obtain the images of the marks 6 on the multiple cargo packages 4, so as to achieve the purpose of reading and identifying all the marks 6.
[0030] When the cargo packaging 4 on the pallet cargo 5 is being processed, there may be Figure 4 The front and back pallets are shown. At this time, the above operation is only performed once to obtain the information of the mark 6 on one side. In order to obtain the information of the marks 6 on the front and back sides, the image acquisition device 2 can be set to be flippable or rotatable. First, when the material is received, the information of the mark 6 on the first side of the pallet 5 facing the image acquisition device 2 is obtained. Then, when the pallet 5 passes the position where the image acquisition device 2 is located and moves away, it is flipped 180 degrees and continues to face the other side of the pallet 5 facing the image acquisition device 2 to complete the above-mentioned identification operation of the mark 6.
[0031] In a preferred embodiment, Figure 5 As shown, in order to ensure the reliable operation of the image acquisition device 2 and avoid the conflict between the two identification processes before and after the flipping, the image acquisition device 2 should be set to two groups, which are respectively responsible for the image acquisition of the two sides of the palletized goods 5 and the identification and reading operation of the mark 6. Further, as shown in the figure, in the process of palletizing, there is also a platter scheme with front and back pallets and left and right pallets on one layer. In order to take into account different palletizing situations, between the two groups of image acquisition devices 2, one group can be designed to move up and down to avoid interference and take into account the acquisition of the upper and lower marks 6, and the other group can be designed to be set left and right relative to the conveyor line 1 to achieve the acquisition and recognition of the image of the mark 6 in the left and right directions. Further, both groups of image acquisition devices 2 can be flipped to have the possibility of acquiring the mark 6 in the two processes of the palletized goods 5 approaching and moving away from the image acquisition device 2.
[0032] The above content only describes the preferred implementation methods of this patent type and does not limit the scope of this patent type. Without departing from the design spirit of this patent type, various modifications and improvements made to the technical solutions of this patent type by ordinary technicians in this field should fall within the protection scope determined by the claims of this patent type.
Claims
1. A method for reading a mark, characterized in that: Obtaining an initial image of the palletized goods (5), and attempting to extract a mark (6) region in the initial image; After the mark (6) area is successfully extracted, the actual distance between the mark (6) and the image acquisition device (2) is calculated based on the image size or image position of the mark (6), and then the relative movement of the mark (6) or the image acquisition device (2) is controlled based on the actual distance, so that the mark (6) falls within the clear imaging range of the image acquisition device (2); After the mark (6) falls within the clear imaging range of the image acquisition device (2), the setting parameters of the image acquisition device (2) are kept unchanged, and the palletized goods (5) are re-imaged to read the information in the mark (6).
2. The method for reading a mark according to claim 1, wherein: The timing of acquiring the initial image of the palletized goods (5) is performed periodically based on a preset time interval or is triggered instantly or with a delay based on a given input signal.
3. The method for reading a mark according to claim 1, wherein: When the mark (6) or the image acquisition device (2) is controlled to move relative to each other, the palletized goods (5) are transported to the clear imaging range of the image acquisition device (2) by controlling the conveyor line (1) or the conveyor time interval is set according to the actual distance during the process of conveying the palletized goods (5) on the conveyor line (1) to determine that the palletized goods (5) enter the clear imaging range of the image acquisition device (2).
4. The method for reading a mark according to claim 1, wherein: After attempting to extract the mark (6) region in the initial image, if the mark (6) region cannot be successfully extracted, the process of obtaining the initial image of the palletized goods (5) is repeated.
5. The method for reading a mark according to claim 4, characterized in that: In the process of repeatedly acquiring the initial image of the palletized goods (5), the timing of acquiring the initial image of the palletized goods (5) is periodically performed based on a preset time interval or is triggered instantly or with a delay based on a given input signal.
6. The method for reading a mark according to claim 1, wherein: When the actual distance between the mark (6) and the image acquisition device (2) is calculated based on the image size or image position of the mark (6), the image size or image position of the invariant feature of the mark (6) is used as the image size D, and a fixed value is determined based on the predetermined invariant feature. , then the actual distance H is .
7. The method for reading a mark according to claim 6, wherein: When controlling the relative movement of the mark (6) or the image acquisition device (2), a shooting distance h for obtaining a clear image is preset, and after the actual distance H between the mark (6) and the image acquisition device (2) is inferred, the image acquisition device (2) or the mark (6) is controlled to move in a corresponding direction by a distance Hh so that the palletized goods (5) enter the clear imaging range of the image acquisition device (2).
8. A conveying system with a mark reading device, characterized in that: include: A conveyor line (1) drives the palletized goods (5) to move; An image acquisition device (2) for acquiring an image of the palletized goods (5); A control system (7) controls the conveyor line (1) and the image acquisition device (2) to execute the mark reading method according to any one of claims 1 to 7.
9. The conveying system with a mark reading device according to claim 8, characterized in that: The image acquisition device (2) is arranged to move up and down perpendicular to the conveying direction of the conveying line (1); Alternatively, the image acquisition device (2) is arranged to be movable left and right perpendicular to the conveying direction of the conveying line (1); Alternatively, the image acquisition device (2) can be flipped 180 degrees along the conveying direction of the conveying line (1).
10. The conveying system with a mark reading device according to claim 8, characterized in that: Two groups of image acquisition devices (2) are provided, and the two groups of image acquisition devices (2) are respectively directed to one end along the conveying direction of the conveying line (1) for shooting; Preferably, the image acquisition device (2) can be flipped 180 degrees along the conveying direction of the conveying line (1).