Device for determining the conveying direction of conveyed objects

Abstract

Device (33) for determining the conveying direction (21, 22) of conveyed objects (15), with an image acquisition device (27) for capturing images of the conveyed objects (15) and an electronic control device (31) which is in signal communication with the image acquisition device (27) and is designed to determine a direction of movement (35) of the objects (35) in the reference system of the image acquisition device (27) by means of image analysis, wherein the electronic control device (31) is configured to detect the orientation of a calibration element (45) positioned in the detection area (29) of the image acquisition device (27) in a calibration mode and to determine a global reference direction (39) in the reference system of the image acquisition device (27) based on the detected orientation.

Description

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

[0002] Such devices are used, for example, when loading, unloading, and transferring goods onto pallets. In particular, in various areas of logistics, it is desirable to automatically identify and differentiate incoming and outgoing goods.

[0003] This requires knowing the conveying direction in a global reference system. However, depending on the mounting position and the orientation of the image acquisition device, there is a difference between the conveying direction in the image acquisition device's reference system and the conveying direction in the global reference system—that is, between the conveying direction in image coordinates and the conveying direction in world coordinates. A user can perform a manual configuration for this conversion, for example, by entering parameters. However, this is cumbersome and prone to errors. Many users prefer not to deal with the orientation of the image acquisition device's reference system.

[0004] One of the aims of the invention is to simplify the determination of the conveying direction of conveyed objects.

[0005] The problem is solved by a device having the features of claim 1.

[0006] According to the invention, the electronic control device is designed to detect the orientation of a calibration element positioned in the detection range of the image acquisition device in a calibration mode and to define a global reference direction in the reference system of the image acquisition device based on the detected orientation.

[0007] The user is thus able to define the global reference direction independently of the image acquisition device's installation position during commissioning. They do not need to concern themselves with the relationship between image coordinates and world coordinates. Defining the global reference direction is simple, quick, and intuitive. In many cases, calibration of the image acquisition device using a calibration element is necessary anyway to enable the derivation of reliable geometric information from the captured images. This calibration process can advantageously be 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 potential for errors is reduced.

[0008] Preferably, the electronic control unit is configured 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 acquisition device to the global reference direction defined in calibration mode, at least in one operating or normal mode of the device. This means that the device determines the conveying direction not only in the image coordinate system, but also in the world coordinate system. This ensures that the actual conveying direction of the objects, relative to the origin and destination, is determined. The user therefore knows without further consideration whether, for example, a specific object is being conveyed away from or towards a storage location.

[0009] The electronic control unit can be configured to calculate the angle of movement between the direction of movement of the objects in the reference frame of the image acquisition device and the global reference direction defined in calibration mode. This enables a particularly simple conversion between the reference frame of the image acquisition device and the global reference frame. In particular, movements that are not parallel to the image coordinate axes can be evaluated more easily in this way. Any difference between the conveying direction in image coordinates and the conveying direction in world coordinates can be specified by an angular value in the range between zero and 360°.

[0010] According to one embodiment of the invention, the electronic control unit is configured to assign a movement angle of zero to any movement of the object in the global reference direction. This means that the global reference direction corresponds to the direction symbol of the calibration element shown. Therefore, when positioning the calibration element, the user immediately understands where the global reference direction points during operation of the device.

[0011] The electronic control unit 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 or a matrix code pattern.

[0012] Another embodiment of the invention provides that the objects are conveyed by means of at least one conveying device from a first loading zone to a second loading zone, or vice versa, and placed in one of the loading zones. The electronic control unit is configured to determine either the first or the second loading zone as the placement location based on the specific conveying direction. In many applications, there is a desire to automatically determine the final placement location of transported goods. Designating one of the two loading zones as the placement location can, for example, support a higher-level control unit in planning the flow of goods. A forklift, pallet truck, robot, belt, roller, or an arrangement of several such conveying devices can be used as the conveying device.

[0013] According to a further embodiment of the invention, the first loading zone is assigned to a transport vehicle and the second loading zone 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 currently handled goods are being loaded onto the truck or into the storage area.

[0014] The electronic control unit can be connected to a display and configured to show instructions in calibration mode for positioning the calibration element within the image acquisition device's detection range such that a directional symbol on the calibration element points either towards the first loading zone or towards the second loading zone. This further simplifies commissioning the device because the display guides the user through the correct calibration process. The user can select whether the default global reference direction is "towards the first loading zone" or "towards the second loading zone."

[0015] Preferably, the electronic control unit is configured to determine the direction of movement of an object within the reference frame of the image acquisition device based on changes in the object's positional coordinates in successively acquired images. The direction of movement in the image can be determined particularly easily via the change in position over time. Preferably, the image acquisition device is configured to acquire images of the detection area at regular intervals.

[0016] The electronic control unit can be configured to identify objects based on optical features such as code patterns or symbols. For example, each object to be conveyed can have a barcode or matrix code applied to it. This identification facilitates object handling in a variety of ways. Since object identification and direction determination are accomplished with the same image capture device—meaning the image capture device performs a dual function—the overall design of the device is relatively simple and cost-effective.

[0017] According to a further embodiment of the invention, the device includes the calibration element. The user can therefore perform the calibration process at any time.

[0018] A directional symbol, particularly an arrow, may be applied to the calibration element. This allows for a particularly intuitive definition of the global reference direction. However, another symbol with a derivable direction could also be applied to the calibration element as a directional symbol, for example, a hazard symbol.

[0019] According to another embodiment, a code pattern containing directional information is applied to the calibration element, wherein the directional information and the directional symbol indicate corresponding directions. The code pattern can also include additional object-specific information.

[0020] Furthermore, a uniform pattern, such as a checkerboard pattern, can be applied to the calibration element. Such a pattern particularly facilitates the compensation of distortions in the imaging process.

[0021] 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 funded 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.

[0022] According to the invention, it is provided that in a calibration process a calibration element is positioned in the detection area of ​​the image acquisition device, the orientation of the calibration element is recognized by means of image analysis and a global reference direction is determined on the basis of the recognized orientation in the reference system of the image acquisition device.

[0023] This allows the user to define the global reference direction independently of the installation position of the image acquisition device during commissioning.

[0024] A method according to the invention may comprise steps that correspond to the features specified above with regard to the design of the electronic control device.

[0025] Further developments of the invention can also be found in the dependent claims, the description and the accompanying drawings.

[0026] The invention is described below by way of example with reference to the drawings. Fig. Figure 1 is a simplified side view of a device according to the invention for determining the conveying direction of conveyed objects. Fig. Figure 2 shows an image sensor of an image acquisition device of the apparatus according to Fig. 1. Fig. Figure 3 shows a marking element for calibrating the device according to Fig. 1.

[0027] In Fig. Figure 1 shows a transport vehicle 11 in the vicinity of a storage room 13. Objects 15, such as pallets of goods, are delivered to or removed from the storage room 13 using the transport vehicle 11. A conveying device 17, such as a forklift, pallet truck, or robot, is provided for transferring the objects 15. Using the conveying 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 a reverse second conveying direction 22 from the storage room 13 to the transport vehicle 11, where they are then placed. Thus, the loading area of ​​the transport vehicle 11 forms a first loading zone 24, while the storage area of ​​the storage room 13 forms a second loading zone 25.

[0028] An optoelectronic image acquisition device 27, such as a matrix camera, is arranged in the vicinity of the storage room 13 in such a way that it can capture images of the objects 15 during the conveying process. In the illustrated embodiment, the detection area 29 of the image acquisition device 27 is located between the transport vehicle 11 and the storage room 13, but in certain applications it could also be located entirely within the transport vehicle 11 or within the storage room 13.

[0029] The image acquisition device 27 is connected to an electronic control unit 31, which is designed for image analysis of the acquired images. In the illustrated embodiment, the image acquisition device 27 and the electronic control unit 31 are housed in a common casing. The electronic control unit 31 is designed to identify the objects 15 based on applied graphic code patterns such as matrix codes (in Fig. 1 not recognizable) to identify, for example, the type of goods being promoted.

[0030] The arrangement consisting of the image acquisition 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 can ascertain whether the object 15 is located in the transport vehicle 11 or in the storage room 13 after the conveying process.

[0031] For this purpose, the electronic control unit 31 first determines as in Fig. Figure 2 shows the direction of movement 35 of the object 15 currently being conveyed in the reference frame of the image acquisition device 27, that is, in the reference frame of the image sensor 36, by determining the change in the position coordinates of the object 15, specifically the recognized code pattern 40, in successively acquired images. Fig. 2 This is illustrated by two representations of the same code pattern 40 at different times.

[0032] The electronic control unit 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 defined global reference direction 39 is determined. An angle of movement 37 of 0° results when the direction of movement 35 coincides with the global reference direction 39, and an angle of movement 37 of 180° results when the direction of movement 35 is opposite to the global reference direction 39. If the determined angle of movement 37 lies within a predefined range around 0°, for example, in a range between -5° and 5°, the electronic control unit 31 defines the first conveying direction 21 as the global conveying direction and designates the storage area 13 as the storage location.If the specified angle of movement 37 lies within a predetermined range around 180°, for example, within a range between 175° and 185°, the electronic control unit 31 determines the second conveying direction 22 as the global conveying direction and sets the transport vehicle 11 as its parking location. The set parking location can be output as a signal to a higher-level control system and / or displayed on a screen.

[0033] In order to enable a simple and quick determination of the global reference direction 39 during the commissioning of the device 33, the electronic control unit 31 is designed to perform a calibration procedure as described below with reference to Fig. 3 is described in more detail.

[0034] When the electronic control unit 31 is in calibration mode, the user is instructed by means of a display (not shown) on the device 33 to position a calibration element 45 within the detection area 29 of the image acquisition 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 acquisition device, with the direction symbol 49 indicating the correct orientation of the calibration element 45 to the user. In addition to the direction symbol 49 and the checkerboard pattern 47, a code pattern similar to the code pattern 40 may be displayed. Fig. 2 on the calibration element 45, which is in 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 area 13, i.e. in the direction of the first loading zone 24 or in the direction of the second loading zone 25.

[0035] After positioning the calibration element 45 and, if necessary, after corresponding confirmation by the user, the electronic control unit 31 detects the orientation of the calibration element 45, for example by reading direction information from the code pattern and / or based on the direction symbol 49, and sets the global reference direction 39, if necessary by saving it, so that it corresponds to the direction defined by the direction symbol 49. The user is then instructed to remove the calibration element 45 from the detection area 29 and switch from calibration mode to operating mode.

[0036] Pointing the direction symbol 49 at the transport vehicle 11 or at the storage room 13 is simple and intuitive for the user. In particular, the user does not need to concern themselves with the orientation of the image sensor 36. Reference symbol list: 11 Transport vehicle 13 storage rooms 15 objects 17 Funding institution 21 first funding direction 22 second funding direction 24 first loading zone 25 second loading zone 27 Image capture device 29 Detection area 31 electronic control unit 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 Directional symbol

Claims

[1] Device (33) for determining the conveying direction (21, 22) of conveyed objects (15), with an image acquisition device (27) for capturing images of the conveyed objects (15) and an electronic control device (31) which is in signal communication with the image acquisition device (27) and is designed to determine a direction of movement (35) of the objects (35) in the reference system of the image acquisition device (27) by means of image analysis, wherein the electronic control device (31) is configured to detect the orientation of a calibration element (45) positioned in the detection area (29) of the image acquisition device (27) in a calibration mode and to determine a global reference direction (39) in the reference system of the image acquisition device (27) based on the detected orientation. [2] Device according to claim 1, wherein the electronic control unit (31) is configured to determine the conveying direction (21, 22) of the conveyed objects (15) in a global reference system by relating the direction of movement (35) of the objects (15) in the reference system of the image acquisition device (27) to the global reference direction (39) defined in the calibration mode. [3] Device according to claim 2, wherein the electronic control unit (31) is configured to calculate an angle of movement (37) between the direction of movement (35) of the objects (15) in the reference system of the image acquisition 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 configured 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 unit (31) is configured to detect the orientation of the calibration element (45) by reading 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 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 reverse direction from the second loading zone (25) to the first loading zone (24) and are placed in one of the loading zones (24, 25) and wherein the electronic control device (31) is configured to determine either the first loading zone (24) or the second loading zone (25) as the placement location based on the determined conveying direction (21, 22). [7] Device according to claim 6, wherein the first loading zone (24) is assigned to a transport vehicle (11) and the second loading zone (25) is assigned to a storage room (13). [8] Device according to claim 6 or 7, wherein the electronic control unit (31) is in signal communication with a display and is configured to display an instruction in the calibration mode to position the calibration element (45) in the detection area (29) of the image detection 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 configured to determine the direction of movement (35) of an object (15) in the reference system of the image acquisition device (27) by means of a change in position coordinates of the object (15) in successively acquired images. [10] Device according to one of the preceding claims, wherein the electronic control unit (31) is configured to identify the objects (15) by means 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 corresponding 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).

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