Device for determining the conveying direction of conveyed objects

Abstract

A device for determining the conveying direction of conveyed objects comprises an image capture device for capturing images of the conveyed objects and an electronic control device that is in signal communication with the image capture device and is designed to determine a direction of movement of the objects in the reference system of the image capture device by means of image analysis. The electronic control device is designed to detect the orientation of a calibration element positioned in the detection range of the image capture device in a calibration mode and to establish a global reference direction in the reference system of the image capture device based on the detected direction symbol.

Description

[0001] The invention relates to a device for determining the conveying direction of conveyed objects, comprising an image capture device for capturing images of the conveyed objects and an electronic control device which is in signal connection with the image capture device and is designed to determine a direction of movement of the objects in the reference system of the image capture device by means of image analysis.

[0002] Such devices are used, for example, for loading, unloading, and reloading goods onto pallets. In particular, various areas of logistics require the automated identification and differentiation of incoming and outgoing goods.

[0003] For this, it is necessary to know the conveying direction in a global reference system. However, depending on the mounting position and orientation of the image capture device, there is a difference between the conveying direction in the reference system of the image capture device and the conveying direction in the global reference system, i.e., between the conveying direction in image coordinates and the conveying direction in world coordinates. To convert, a user can perform a manual configuration, for example, by entering parameters. However, this is tedious and error-prone. Many users do not want to concern themselves with the orientation of the reference system of the image capture device.

[0004] DE 10 2018 108 939 A1 discloses a system for measuring workpieces, which comprises an arrangement of several sensors with integrated light sources and time controls, wherein the sensors are active alternately over time.

[0005] DE 10 2022 201 311 A1 discloses a monitoring device for a warehouse, which comprises a camera and an evaluation device for evaluating the camera image. The evaluation device determines the positions of articles relative to the designated storage locations.

[0006] It is an object of the invention to simplify the determination of the conveying direction of conveyed objects.

[0007] The problem is solved by a device having the features of claim 1.

[0008] According to the invention, the electronic control device is designed to detect, in a calibration mode, the orientation of a calibration element positioned in the detection range of the image capture device and to define a global reference direction in the reference system of the image capture device based on the detected orientation.

[0009] The user is thus able to define the global reference direction independently of the installation position of the image acquisition device when commissioning the device. They do not need to worry about the relationship between image coordinates and world coordinates. The global reference direction can be defined simply, quickly, and intuitively. In many cases, the image acquisition device must be calibrated using a calibration element anyway to enable the derivation of reliable geometric information from the acquired images. This calibration process can be advantageously used to define the global reference direction by appropriately aligning the calibration element. Commissioning a device according to the invention is therefore particularly quick and easy. Furthermore, the susceptibility to errors is reduced.

[0010] Preferably, the electronic control device is designed to determine the conveying direction of the conveyed objects in a global reference system by relating the direction of movement of the objects in the reference system of the image capture device to the global reference direction defined in the calibration mode, at least in an operating mode or normal mode of the device. This means that the device determines the conveying direction not, or not only, in the image coordinate system, but rather in the world coordinate system. This ensures that the actual conveying direction of the objects with respect to the origin and destination is determined as the conveying direction. The user therefore knows without further consideration whether, for example, a specific object is being conveyed away from a storage location or towards a storage location.

[0011] The electronic control device can be configured to calculate a movement angle between the direction of movement of the objects in the reference system of the image capture device and the global reference direction defined in calibration mode. This enables particularly simple conversion between the reference system of the image capture device and the global reference system. In particular, movements that are not parallel to the image coordinate axes can be evaluated in a simplified manner. Any difference between the conveying direction in image coordinates and the conveying direction in world coordinates can be specified by an angle value in the range between zero and 360°.

[0012] According to one embodiment of the invention, the electronic control device is configured to assign a movement angle of zero to a movement of the object in the global reference direction. This means that the global reference direction corresponds to the displayed direction symbol of the calibration element. Thus, when positioning the calibration element, the user immediately knows where the global reference direction points during operation of the device.

[0013] The electronic control device can be configured to detect the orientation of the calibration element by reading directional information from a code pattern located on the calibration element. The code pattern can be a barcode pattern or a matrix code pattern.

[0014] A further embodiment of the invention provides that the objects are to be conveyed by means of at least one conveyor device from a first loading zone to a second loading zone or in the opposite direction from the second loading zone to the first loading zone and are to be deposited in one of the loading zones. The electronic control device is designed to define either the first loading zone or the second loading zone as the deposit location based on the determined conveying direction. In many application situations, there is a desire to automatically determine the final deposit location of transported goods. Defining one of the two loading zones as the deposit location can, for example, support a higher-level control unit in planning the flow of goods. The conveyor device can be a forklift truck, a pallet truck, a robot, a belt, belt or roller conveyor or an arrangement comprising several such conveyor devices.

[0015] According to a further embodiment of the invention, the first loading zone is assigned to a transport vehicle, and the second loading zone is assigned to a storage area. The transport vehicle can, in particular, be a truck used to deliver goods to a warehouse. It is advantageous for the warehouse operator to know whether the goods currently being handled are being brought into the truck or into the storage area.

[0016] The electronic control device can be signal-connected to a display and configured to display, in calibration mode, an instruction to position the calibration element within the detection range of the image capture device such that a direction symbol on the calibration element points toward the first loading zone or toward the second loading zone. Commissioning of the device is further simplified because the display guides the user to the correct calibration. The user can select whether the default global reference direction is "toward the first loading zone" or "toward the second loading zone."

[0017] Preferably, the electronic control device is configured to determine the direction of movement of an object in the reference system of the image capture device based on a change in the object's position coordinates in successively captured images. The direction of movement in the image can be determined particularly easily via the temporal change in position. Preferably, the image capture device is configured to capture images of the capture area at regular time intervals.

[0018] The electronic control device can be configured to identify the objects based on optical features such as code patterns or symbols. For example, a barcode or matrix code can be applied to each of the objects to be conveyed. This identification facilitates handling of the objects in a variety of ways. Since object identification, on the one hand, and direction determination, on the other, are accomplished with one and the same image capture device, thus fulfilling a dual function, the overall design of the device is relatively simple and cost-effective.

[0019] According to a further embodiment of the invention, the device comprises the calibration element. The user can thus perform the calibration process at any time.

[0020] A direction symbol, particularly an arrow, can be applied to the calibration element. This allows for a particularly intuitive definition of the global reference direction. However, another symbol with a deducible direction could also be applied to the calibration element as a direction symbol, for example, a hazardous goods sign.

[0021] According to a further embodiment, a code pattern with directional information is applied to the calibration element, wherein the directional information, on the one hand, and the directional symbol, on the other, indicate matching directions. The code pattern can also contain additional object-specific information.

[0022] Furthermore, a uniform pattern, such as a checkerboard pattern, can be applied to the calibration element. Such a pattern facilitates the compensation of image distortions.

[0023] The invention also relates to a method for determining the conveying direction of conveyed objects, in particular by means of a device as described above, comprising the steps: Capturing images of the conveyed objects using an image capture device, and Determining the direction of movement of objects in the reference system of the image acquisition device using image analysis.

[0024] According to the invention, it is provided that in a calibration process a calibration element is positioned in the detection range of the image capture device, the orientation of the calibration element is detected by means of image analysis and a global reference direction is determined on the basis of the detected orientation in the reference system of the image capture device.

[0025] This allows the user to define the global reference direction when commissioning the device, regardless of the installation position of the image acquisition device.

[0026] A method according to the invention may comprise steps which correspond to the features specified above with regard to the design of the electronic control device.

[0027] Further developments of the invention can also be found in the dependent claims, the description and the accompanying drawings.

[0028] The invention is described below by way of example with reference to the drawings. Fig. 1 is a simplified side view of a device according to the invention for determining the conveying direction of conveyed objects. Fig. 2 shows an image sensor of an image capture device of the device according to Fig. 1. Fig. 3 shows a marking element for calibrating the device according to Fig. 1.

[0029] In Fig. 1 shows a transport vehicle 11 in the vicinity of a storage room 13. Objects 15, such as pallets of goods, are delivered or removed by means of the transport vehicle 11. A conveyor device 17, for example a forklift truck, a pallet truck, or a robot, is provided for reloading the objects 15. By means of the conveyor device 17, the objects 15 can be conveyed in a first conveying direction 21 from the transport vehicle 11 to the storage room 13 or in an opposite second conveying direction 22 from the storage room 13 to the transport vehicle 11 and then deposited. Thus, the loading area of ​​the transport vehicle 11 forms a first loading zone 24, while the parking area of ​​the storage room 13 forms a second loading zone 25.

[0030] An optoelectronic image capture device 27, such as a matrix camera, is arranged in the vicinity of the storage space 13 such that it can capture images of the objects 15 during the conveying process. In the illustrated embodiment, the capture area 29 of the image capture device 27 is located between the transport vehicle 11 and the storage space 13, but in certain applications, it could also be located entirely within the transport vehicle 11 or the storage space 13.

[0031] The image capture device 27 is connected to an electronic control device 31, which is designed for image analysis of the captured images. In the embodiment shown, the image capture device 27 and the electronic control device 31 are housed in a common housing. The electronic control device 31 is designed to identify the objects 15 using applied graphic code patterns such as matrix codes (in Fig. 1 not recognizable) in order to determine, for example, the type of goods being promoted.

[0032] The arrangement of the image capture device 27 and the electronic control device 31 also forms a device 33 for determining the conveying direction 21, 22 of the conveyed objects 15. This device 33 can detect whether an object 15 is conveyed in the first conveying direction 21 or in the second conveying direction 22, so that a user becomes aware of whether the object 15 is located in the transport vehicle 11 or in the storage room 13 after the conveying process.

[0033] For this purpose, the electronic control device 31 first determines as shown in Fig. 2 shows the direction of movement 35 of the currently conveyed object 15 in the reference system of the image capture device 27, i.e. in the reference system of the image sensor 36, by determining the change in the position coordinates of the object 15, specifically of the recognized code pattern 40, in successively captured images. In Fig. 2 this is illustrated by two representations of the same code pattern 40 at different times.

[0034] The electronic control device 31 then determines the conveying direction 21, 22 in a global reference system based on the direction of movement 35. For this purpose, the angle of movement 37 between the direction of movement 35 and a specified global reference direction 39 is determined. This results in a movement angle 37 of 0° if the direction of movement 35 coincides with the global reference direction 39, and a movement angle 37 of 180° if the direction of movement 35 is opposite to the global reference direction 39. If the determined angle of movement 37 lies within a predetermined range around 0°, for example, in a range between -5° and 5°, the electronic control device 31 determines the first conveying direction 21 as the global conveying direction and specifies the storage room 13 as the storage location.If the determined angle of movement 37 lies within a predetermined range around 180°, for example, between 175° and 185°, the electronic control device 31 determines the second conveying direction 22 as the global conveying direction and specifies the transport vehicle 11 as the parking location. The specified parking location can be output as a signal to a higher-level control system and / or displayed on a display.

[0035] In order to be able to carry out a simple and rapid determination of the global reference direction 39 when commissioning the device 33, the electronic control device 31 is designed to carry out a calibration process as described below with reference to Fig. 3 is described in more detail.

[0036] When the electronic control device 31 is in a calibration mode, the user is instructed by means of a display (not shown) of the device 33 to position a calibration element 45 in the detection area 29 of the image capture device 27. As shown, the calibration element 45 has a checkerboard pattern 47 and a direction symbol 49, here in the form of an arrow. Calibration elements 45 of the type shown are generally used to determine the imaging geometry of the image capture device, wherein the direction symbol 49 indicates to the user the correct orientation of the calibration element 45. In addition to the direction symbol 49 and the checkerboard pattern 47, a code pattern similar to the code pattern 40 according to Fig. 2 on the calibration element 45, which is Fig.3, however, is not shown. In the device 33 according to the invention, the user is instructed to align the calibration element 45 such that the direction symbol 49 points in the direction of the transport vehicle 11 or in the direction of the storage space 13, i.e., in the direction of the first loading zone 24 or in the direction of the second loading zone 25.

[0037] After positioning the calibration element 45 and, if applicable, after corresponding confirmation by the user, the electronic control device 31 detects the orientation of the calibration element 45, for example, by reading directional information from the code pattern and / or based on the directional symbol 49, and sets the global reference direction 39, if applicable by saving it, so that it coincides with the direction defined by the directional symbol 49. The user is then instructed to remove the calibration element 45 from the detection area 29 and to switch from calibration mode to operating mode.

[0038] Pointing the direction symbol 49 toward the transport vehicle 11 or the storage space 13 is simple and intuitive for the user. In particular, the user does not have to worry about the alignment of the image sensor 36. List of reference symbols: 11 Transport vehicle 13 storage room 15 objects 17 Conveyor system 21 first conveying direction 22 second conveying direction 24 first loading zone 25 second loading zone 27 Image capture device 29 Detection range 31 electronic control device 33 Device for determining the conveying direction 35 Direction of movement 36 image sensor 37 angles of movement 39 global reference direction 40 code patterns 45 Calibration element 47 checkerboard patterns 49 Direction symbol

Claims

[1] Device (33) for determining the conveying direction (21, 22) of conveyed objects (15), with an image capture device (27) for capturing images of the conveyed objects (15) and an electronic control device (31) which is in signal connection with the image capture device (27) and is designed to determine a direction of movement (35) of the objects (35) in the reference system of the image capture device (27) by means of image analysis, wherein the electronic control device (31) is designed to detect, in a calibration mode, the orientation of a calibration element (45) positioned in the detection area (29) of the image capture device (27) and to define a global reference direction (39) on the basis of the detected orientation in the reference system of the image capture device (27). [2] Device according to claim 1, wherein the electronic control device (31) is designed to determine the conveying direction (21, 22) of the conveyed objects (15) in a global reference system by setting the direction of movement (35) of the objects (15) in the reference system of the image capture device (27) in relation to the global reference direction (39) defined in the calibration mode. [3] Device according to claim 2, wherein the electronic control device (31) is designed to calculate a movement angle (37) between the direction of movement (35) of the objects (15) in the reference system of the image capture device (27) and the global reference direction (39) defined in the calibration mode. [4] Device according to claim 3, wherein the electronic control device (31) is designed to assign a movement angle (37) of zero to a movement of the object (15) in the global reference direction (39). [5] Device according to one of the preceding claims, wherein the electronic control device (31) is designed to detect the orientation of the calibration element (45) by reading out directional information from a code pattern located on the calibration element (45). [6] Device according to one of the preceding claims, wherein the objects (15) are to be conveyed by means of at least one conveying device (17) from a first loading zone (24) to a second loading zone (25) or in the opposite direction from the second loading zone (25) to the first loading zone (24) and are to be deposited in one of the loading zones (24, 25), and wherein the electronic control device (31) is designed to define either the first loading zone (24) or the second loading zone (25) as the deposit location based on the determined conveying direction (21, 22). [7] Device according to claim 6, wherein the first loading zone (24) is associated with a transport vehicle (11) and the second loading zone (25) is associated with a storage space (13). [8] Device according to claim 6 or 7, wherein the electronic control device (31) is in signal connection with a display and is designed to display an instruction in the calibration mode to position the calibration element (45) in the detection area (29) of the image capture device (27) such that a direction symbol (49) located on the calibration element (45) points in the direction of the first loading zone (24) or in the direction of the second loading zone (25). [9] Device according to one of the preceding claims, wherein the electronic control device (31) is designed to determine the direction of movement (35) of an object (15) in the reference system of the image capture device (27) on the basis of a change in position coordinates of the object (15) in successively captured images. [10] Device according to one of the preceding claims, wherein the electronic control device (31) is designed to identify the objects (15) on the basis of optical features such as code patterns (40) or symbols. [11] Device according to one of the preceding claims, wherein the device (33) comprises the calibration element (45). [12] Device according to claim 11, wherein a direction symbol (49), in particular an arrow, is applied to the calibration element (45). [13] Device according to claim 12, wherein a code pattern with directional information is applied to the calibration element (45) and wherein the directional information on the one hand and the directional symbol (49) on the other hand indicate matching directions. [14] Device according to one of claims 11 to 13, wherein a uniform pattern such as a checkerboard pattern (47) is applied to the calibration element (45). [15] Method for determining the conveying direction (21, 22) of conveyed objects (15), in particular by means of a device (33) according to one of the preceding claims, comprising the steps: Capturing images of the conveyed objects (15) by means of an image capturing device (27), and Determining the direction of movement (35) of the objects (15) in the reference system of the image capture device (27) by means of image analysis, wherein in a calibration process a calibration element (45) is positioned in the detection area (29) of the image capture device (27), the orientation of the calibration element (45) is detected by means of image analysis and a global reference direction (39) is determined on the basis of the detected orientation in the reference system of the image capture device (27).

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