Method and device for monitoring a dispensing of a liquid and beverage vending machine

Abstract

The invention relates to a method (500) for monitoring the dispensing of a liquid as a jet (225) via a nozzle (110) of an outlet of a beverage vending machine (100) into a container (112). For this purpose, an image depicting the jet (225) is captured. A position of an end of the jet (225) facing away from the nozzle (110) is determined using the image, and a fill level of the liquid in the container (112) is determined using the end position of the jet (225).

Description

[0001] The invention relates to a method for monitoring a dispensing of a liquid, a device for monitoring a dispensing of a liquid and a beverage vending machine.

[0002] DE 10 2016 107 086 A1 describes a volume and overflow detection system for a beverage vending machine.

[0003] The approach presented here aims to provide an improved method for monitoring a dispensing of a liquid, an improved device for monitoring a dispensing of a liquid and an improved beverage dispenser.

[0004] According to the invention, this object is achieved by a method for monitoring the dispensing of a liquid, a device for monitoring the dispensing of a liquid, and a beverage vending machine having the features of the main claims. Advantageous embodiments and further developments of the invention are set out in the following subclaims.

[0005] The advantages achievable with the invention consist in a reliable detection of the fill level in a vessel which is placed under an outlet, which can prevent the vessel from being overfilled.

[0006] A method for monitoring a dispensing of a liquid dispensed as a jet into a vessel via a nozzle of a beverage dispenser outlet comprises the following steps: Capturing an image depicting the beam; Determining an end position of the jet remote from the nozzle using the image; and Determining a fill level of the liquid in the vessel using the end position of the jet.

[0007] According to one embodiment, the liquid can be a liquid substance such as water or coffee. The drinks dispenser can, for example, be designed as a coffee machine, in particular a fully automatic coffee machine. The image can be captured using a suitable image recording device, for example, a camera.

[0008] An image of the jet can be recognized in the image using suitable image analysis. Known methods can be used for this purpose. The fill level can be determined, for example, simply from the length of the jet, from a difference between the end position and a known position of the nozzle, or from a difference between fill levels determined successively in time. For example, the end position of the jet can first be determined in image coordinates as one end of the image of the jet in the image and then converted into world coordinates, for example a coordinate system anchored to the vending machine. Likewise, for example, the total length of the jet can first be determined in image coordinates and then converted into world coordinates.According to one embodiment, the end of the jet can be determined without separately detecting the surface of the beverage already inside the vessel, also referred to as the filling surface, for example, using a special image analysis to detect the surface. Thus, it may be sufficient to detect a line attributable to the jet in the image using a suitable image analysis and to use one end of the line as the end of the jet.

[0009] In the determining step, a jet length of the jet can be determined based on a distance between the end position of the jet and a nozzle position, and in the determining step, the fill height can be determined as the difference between a nozzle height and the jet length. According to one embodiment, the end position of the jet can be defined as an intersection point with the fill surface. According to one embodiment, known algorithms for line detection, such as the Hough transform, can be used to determine the length of the jet in the image. For this purpose, the actual jet length in centimeters can be calculated from the line length in the image.For example, a corresponding formula can be used to calculate the fill level from the camera height, the camera's focal length, a structural horizontal distance between the camera and the nozzle in millimeters, and a distance in the image between the end of the jet and the orthogonal point in the camera image in pixels. According to one embodiment, the jet length determines the distance between the nozzle and the impact surface, such as the beverage surface. Subtracting the jet length from the outlet height or the height of the outlet nozzle results in the fill level.

[0010] The method may include a step of rectifying the image to obtain a rectified image. In the determining step, the final position of the beam can be determined using the rectified image. This allows, for example, the beam length to be determined more precisely. This enables the use of the Hough line filter shown above as an example, because in the rectified, preferably orthonormal, images, lines are straight that would otherwise be curved in the distorted image.

[0011] The method can also include a step of detecting the beam in the image using a predetermined search corridor within the image. A width of the corridor can compensate for inaccuracies in the nozzle positions, camera alignment, or the straightness of the beam. The clear limitation to a corridor leads to greater robustness. The runtime of the beam detection is linear in complexity and fast. Due to an optionally known nozzle height and a beam path, only a portion of the image with the corridor needs to be evaluated. Compared to the linear runtime for a beam, the detection of a circular fill surface, on the other hand, is cubic, with three dimensions, and correspondingly more complex.

[0012] Additionally or alternatively, the beam can be detected in the image using a motion filter. Thus, the motion in the beam can be used as a special characteristic to separate it from the background and capture it more robustly. Since the beam has a high flow velocity, it can be separated from the static background using motion filters.

[0013] In the determination step, the fill level can be determined using the final position of the jet, a distance between the image pickup device and the nozzle, and the nozzle height. Using these input variables and known geometric relationships, the fill level can be easily determined.

[0014] The fill level can be compared to a threshold value, and in a stopping step, the beam output can be stopped depending on the result of the comparison. According to one embodiment, the threshold value is less than or equal to 70% of the vessel height. According to an alternative embodiment, the threshold value can also be less than or equal to 80% of the vessel height, or less than or equal to 90% of the vessel height. Filling of the vessel is stopped if an overflow threatens; for this purpose, for example, the vessel height is compared with the fill level.

[0015] In the capturing step, an image depicting a second beam can be captured. In reality, the two beams can be parallel and spaced at the same distance from each other as the distance between the two nozzles. In the determining step, a position of an end of the second beam facing away from a second nozzle can be determined using the image, and in the ascertaining step, a second fill level of the liquid in the vessel or a second vessel can be determined using the end position of the second beam. According to one embodiment, precision can be improved by comparing the two beams.

[0016] The steps of detecting, determining, and ascertaining can be carried out repeatedly to determine a temporal progression of the fill level. In a determining step, a vessel shape of the vessel can be ascertained using the temporal progression of the fill level and a temporal progression of a volume filled using the jet. The volume of liquid dispensed by the jet can, for example, be detected using a flow sensor or determined from the operation of a pump for conveying the liquid to the nozzle. The evaluation of the jet length is independent of position and vessel shape and is therefore very robust, since errors from an alternatively implementable direct vessel detection are not reflected in the fill level detection.The evaluation of the filling level curve is less complex than an alternative evaluation of the filling surface, since it is not necessary to take into account that the filling surface expands due to the shape of the cup.

[0017] A corresponding device for monitoring the dispensing of a liquid can be configured to execute and / or control the steps of the method in appropriate units. This embodiment of the invention in the form of a device also allows the problem underlying the invention to be solved quickly and efficiently.

[0018] The device can be designed to read in input signals and to determine and provide output signals using the input signals. An input signal can, for example, represent a sensor signal that can be read in via an input interface of the device. An output signal can represent a control signal or a data signal that can be provided at an output interface of the device. The device can be designed to determine the output signals using a processing rule implemented in hardware or software. For example, the device can comprise a logic circuit, an integrated circuit, or a software module and can, for example, be implemented as a discrete component or be comprised of a discrete component.

[0019] A beverage vending machine, in particular a fully automatic coffee machine, can have at least one outlet, which in turn comprises at least one nozzle for dispensing a jet of liquid into a container. Furthermore, the beverage vending machine can comprise an embodiment of the device for monitoring the dispensing of a liquid.

[0020] The device may comprise an image recording device configured to capture the image depicting the jet. Furthermore, the device may comprise an evaluation device configured to use the image to determine the position of an end of the jet facing away from the nozzle and to determine the fill level of the liquid in the vessel using the position of the end of the jet facing away from the nozzle. According to one embodiment, this may be referred to as camera-based fill level detection in the fully automatic coffee machine.

[0021] The image pickup device can be positioned at the same height as the nozzles. This allows the image pickup device to capture as much of the jet as possible. If the jet is visible all the way to the nozzle, filling large containers up to the nozzle tip is also possible. Furthermore, the height of the image pickup device can be set equal to the initial height of the jet. This facilitates the determination of the fill level.

[0022] Although the approach described is based on a household appliance, the approach described here can be used accordingly in connection with a commercial or professional device, for example a medical device, such as a cleaning or disinfection device, a small-scale sterilizer, a large-scale disinfector or a container washing system.

[0023] An embodiment of the invention is shown purely schematically in the drawings and is described in more detail below. It shows Fig. 1 a schematic representation of an embodiment of a drinks vending machine; Fig. 2 a schematic representation of an embodiment of a dispensing area of ​​a beverage vending machine; Fig. 3 is a schematic representation of an embodiment of an image of an image recording device; Fig. 4 shows an embodiment of an image of an image recording device; and Fig. 5 an embodiment of a flow diagram of a method for monitoring a dispensing of a liquid.

[0024] Fig. Figure 1 shows a schematic representation of an embodiment of a beverage dispenser 100, for example in the form of a fully automatic coffee machine. According to known fully automatic coffee machines, the beverage dispenser 100 has a dispenser 105 with at least one nozzle 110 for dispensing a beverage into a container 112.

[0025] The outlet 105 is optionally designed to be movable. According to one embodiment, a user can adjust the height of the outlet.

[0026] An image capture device 115 is arranged at the outlet 105. The image capture device 115 is configured to capture images of an area below the outlet 105. Optionally, the beverage vending machine 100 includes an illumination device 120 configured to illuminate a capture area of ​​the image capture device 115.

[0027] The beverage vending machine 100 is configured to determine the fill level of the dispensed beverage in the container by appropriately evaluating at least one image captured by the image recording device 115. For this purpose, a beam for dispensing the beverage, depicted in the image, is detected in the image. The fill level is determined using an end of the beam depicted in the image.

[0028] According to one embodiment, the image recording device 115 comprises a camera or is configured as a camera. According to one embodiment, the illumination device 120 may comprise a suitable light source, for example, an LED light.

[0029] According to one embodiment, the beverage vending machine 100 is equipped with the image recording device 115 and the lighting device 120 in a dispensing area 125 to monitor the beverage dispensing and prevent possible overflow of containers. The image recording device 115 is installed such that it can capture the container contents and a liquid stream.

[0030] To prepare a beverage, coffee in this embodiment, and dispense it from the outlet 105, the beverage machine 100 optionally has a bean container 130 and a water tank 135. From the water tank 135, the water is pumped by a pump 140 through a heating block 145 for heating the water and to a brewing unit 150. The brewing unit 150 enables the coffee to be prepared. The beverage, in this case the prepared coffee, is then dispensed via the nozzle 110 of the outlet 105.

[0031] An optional operating display 155 allows the user to select various beverage configurations and display a beverage preparation process. To control the operating display 155 and other features of the beverage dispenser 100, the beverage dispenser 100 includes a control unit 160.

[0032] An evaluation device 165 is optionally integrated into the control unit 160, which, according to one embodiment, evaluates signals supplied by the image recording device 115.

[0033] Fig. 2 shows an embodiment of a dispensing area 200 of a beverage vending machine, as can be seen, for example, from Fig. 1. Outlet 105 here has a second nozzle 210 in addition to nozzle 110. According to the illustrated embodiment, first nozzle 110 and second nozzle 210 are used together to fill vessel 112. Alternatively, nozzles 110, 210 can be used to fill two vessels with a beverage simultaneously.

[0034] For example, the image recording device 115 is arranged centrally between the nozzles 110, 210. In the Fig. 2 shows a viewing area 215 of the image capture device 115. The viewing area 215 includes the dispensing area 125 below the outlet 105. According to one embodiment, the dispensing area 125 is shaped to accommodate containers, such as cups.

[0035] Using the first nozzle 110, a first jet 225 and using the second nozzle 210, a second jet 230 of liquid are discharged into the vessel 112. The two jets 225, 230 of liquid emerging from the nozzle 110 and the second nozzle 210 lie within the field of view 215 of the image pickup device 115. According to this embodiment, the two jets 225, 230 flow into the vessel 112, which is also within the field of view 215. According to an alternative embodiment, the field of view 215 can capture up to two vessels, each of which is then filled by one of the jets 225, 230.

[0036] An image captured using the image capture device 115 completely or partially images the beams 225, 230. At least one end of the beams 225, 230 facing away from the nozzles 110, 210 is imaged in the image and can be used to determine the fill level of the beverage within the vessel 112.

[0037] If only a single nozzle 110 is present or used, the image captured by the image pickup device 115 represents only a single beam 225, which, however, can be used in a corresponding manner to determine the fill level of the beverage within the vessel 112.

[0038] According to one embodiment, the beam 225 of the outlet nozzle 110 is captured and evaluated using only one camera, here the image recording device 115, and optionally an existing outlet illumination. With two outlet nozzles, here the nozzles 110, 210, the two parallel beams 225, 230 are captured at a known distance, i.e., the nozzle spacing. For this purpose, one or more images are taken, optionally with outlet illumination. By calculating with known variables, such as the distance between the nozzles 110, 210, the distance between the image recording device 115 and the nozzles 110, 210, and the position of the nozzles 110, 210 in the outlet with respect to height, the fill level and a filling speed can be calculated. According to one embodiment, these calculations are very simple because only linear vectors can be considered, and no complicated image acquisition is required.Image acquisition and evaluation are also simple because the jet 225 from the nozzle 110 has a clear contour and is always recognizable from the surroundings.

[0039] Fig. 3 shows a schematic representation of an embodiment of an image 315 captured using an image recording device as described, for example, with reference to the preceding figures. According to the embodiment described with reference to Fig. 2, the image 315 depicts the vessel 112 in the dispensing area from a bird's eye view.

[0040] Image 315 depicts the two jets 225, 230 flowing into the vessel 112, which impinge on a beverage surface 300 of a beverage already located within the vessel 112. The beverage surface 300 represents the current fill level of the beverage. Thus, one end of the jets 225, 230 within the vessel 112 corresponds to the fill level. By appropriate image analysis of the image 315, an image of at least one of the jets 225, 230 within the image 315 and an end of this jet 225, 230 located within the vessel 112 are determined. The fill level of the beverage within the vessel 112 can be determined from the position of the end.

[0041] The fill level or a fill level curve over time is optionally used for overflow detection. In overflow detection, the relevant information is not the fill level itself, but rather the fact that the fill level changes as the vessel 112 is filled. Based on the device geometry, the exact path of the beams 225, 230 during filling is known and can be scanned with the image recording device. This reduces image processing to precisely this generally rectilinear beam, for example, to the first beam 225.

[0042] The fill level can be read geometrically from the beam length of the beams 225, 230, for which no information about the shape of the vessel 112 is necessary, and the fill level does not have to be read from other variables, such as the size and position of the beverage surface 300. Dimensions of the surface itself are often difficult to determine because the surface is not smooth, especially in the case of milk foam. The surface can also reflect on the inner edge of the vessel 112 and is sometimes seen twice, which is why determining the fill level via the beam length is advantageous. In addition, when measuring the surface, the size of the vessel 112 must be known in order to be precise, whereby inaccuracies in the vessel 112 will result in inaccuracies in the fill level.

[0043] According to one embodiment, the fill level is calculated by subtracting the jet length from the nozzle height. However, this is not the case if the vessel 112 is not positioned centrally below the outlet, and the jets 225, 230 impinge on the vessel wall rather than the vessel bottom.

[0044] The fill level may not be available directly from the bottom of the vessel if the cup is not centered and at least one of the beams 225, 230 initially strikes the vessel wall or is obscured by the vessel wall from the perspective of the image recording device. However, it is available as soon as the immersion point of one of the two beams 225, 230 in the fill surface appears in the camera image.

[0045] To easily detect the rays 225, 230 in the image 315, search corridors 320, 325 can be used, which can also be referred to simply as corridors and which indicate an expected path of the rays 225, 230 in the image 315. Thus, an evaluation of the image 315 within the search corridors 320, 325 or at least within one of the search corridors 320, 325 is sufficient. According to one embodiment, the search corridors 320, 325 extend to the depth of the vessel bottom, for example, the bottom of a cup.

[0046] The beams 225, 230 do not need to be visible from the nozzles, and only an intersection point 305 with the filling surface 300 is important here. However, the more of the beams 225, 230 are visible, the more accurately and robustly they can be detected with their orientation in corridors 320, 325, and the intersection point 305 with the beverage surface can be determined.

[0047] According to one embodiment, corridors 320, 235 are each a rectangular region within an expected range of rays 225, 230. Corridors 320, 325 are designed to simplify detection of rays 225, 230 and to restrict a range of image analysis. The region can also be trapezoidal.

[0048] By knowing the distances and alignment of the image acquisition device and the nozzles, the beams 225, 230 can be delimited in the image by the optional corridors 320, 325. From the camera perspective, the beams 225, 230 move away from the nozzles toward the vessel 112 and thus become smaller, so that the corridors 320, 325 are narrower at the bottom of the image than at the top. The width of the corridors 320, 325 can compensate for inaccuracies in the nozzle positions, the camera alignment, or the straightness of the beams 225, 230.

[0049] Since the rays 225, 230 have a high flow velocity, according to an alternative embodiment, they can additionally be separated from the static background by motion filters.

[0050] According to one embodiment, the precision with which the fill level is determined for one vessel 112 is improved by comparing both beams 225, 230. For two vessels, one of the beams 225, 230 each flows into a vessel, and two individual fill levels are assigned to the two beams 225, 230.

[0051] Fig. Figure 4 shows an illustration of an embodiment of an image 315 from the image recording device, as described with reference to the preceding figures. The image 315 from the image recording device is shown before optional rectification. Here, too, the rays 225, 230 from the outlet into the vessel 112 are visible. In addition, the beverage surface 300 and the ends of the rays 225, 230 that open into the beverage surface 300 are visible.

[0052] Fig. Figure 5 shows an embodiment of a flowchart of a method 500 for monitoring the dispensing of a liquid from the beverage dispenser into a container. For this purpose, at least one image captured using an image recording device is used, as described with reference to the preceding figures.

[0053] Using the image capture device, the image is captured in a capture step 501. The image depicts at least one jet emerging from the nozzles of the outlet.

[0054] In response to the acquisition step 501, an optional step of rectifying the image 503 is performed to obtain a rectified image. According to one embodiment, the image is rectified such that the rays have a straight shape. For example, the camera image is rectified such that lines are straight in orthonormal space. Due to gravity, the output beam is sufficiently straight.

[0055] In a step 505, the imaged beam is detected, or, if appropriate, multiple beams imaged in the image are detected. Optionally, in step 505, at least one predetermined search corridor is used, within which the image is searched for at least one beam. Additionally or alternatively, in one embodiment, step 505 of detecting the beam or beams is optionally performed in conjunction with a motion filter.

[0056] In response to the detection step 505, a step 507 of determining a position of an end of the jet facing away from the nozzle is performed using the image. In step 507, the end position of the jet is optionally determined using the rectified image.

[0057] The position of the end of the jet facing away from the nozzle is used in a step 509 to determine the filling level of the liquid in the vessel.

[0058] To optionally determine a temporal progression of the fill level, at least steps 501, 507, 509 are repeated at least once, optionally multiple times. Optionally, the temporal progression of the fill level is used to determine, in a determination step 511, a vessel shape of the vessel being filled using the jet. In step 511, an amount of a volume of the beverage already poured into the vessel is optionally used to determine the vessel shape.

[0059] To determine how full the vessel is, a step 513 of comparing the fill level with a threshold value is also performed. Depending on the result of step 513, the beam output is stopped in step 515.

[0060] This method 500 is simple and robust compared to alternative methods. Furthermore, method 500 can also be combined with other methods, such as determination from the fill surface, to further increase robustness through "sensor fusion." QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2016 107 086 A1

[0002]

Claims

[1] A method (500) for monitoring a dispensing of a liquid dispensed as a jet (225) via a nozzle (110) of an outlet of a beverage vending machine (100) into a vessel (112), the method (500) comprising the following steps: capturing (501) an image (315) depicting the beam (225); Determining (507) a position of an end of the jet (225) facing away from the nozzle (110) using the image (315); and Determining (509) a fill level of the liquid in the vessel (112) using the end position of the beam (225). [2] Method (500) according to claim 1, wherein in the step of determining (507), a jet length of the jet (225) is determined based on a distance between the end position of the jet (225) and a nozzle position, and in the step of determining (509), the fill level is determined as the difference between a nozzle height and the jet length. [3] Method (500) according to one of claims 1 or 2, comprising a step of rectifying (503) the image (315) to obtain a rectified image, wherein in the step of determining (507) the final position of the beam (225) is determined using the rectified image. [4] Method (500) according to one of the preceding claims, comprising a step of detecting (505) the beam (225) in the image (315) using a predetermined search corridor (330, 325) within the image (315), and / or using a motion filter. [5] Method (500) according to one of the preceding claims, wherein in the step of determining (509) the fill level is determined using the end position of the jet (225), a distance between the image recording device (115) and the nozzle (110) and the nozzle height. [6] Method (500) according to one of the preceding claims, comprising a step of comparing the fill level with a threshold value, and a step of stopping (515) an output of the beam (225) depending on a result of the comparison. [7] Method (500) according to one of the preceding claims, wherein in the step of capturing (501) the image (315) is captured which depicts a second jet (225), in the step of determining a position of an end of the second jet (230) facing away from a second nozzle (210) is determined using the image (315), and in the step of determining (509) a second fill level of the liquid in the vessel (112) or a second vessel is determined using the end position of the second jet (230). [8] Method (500) according to one of the preceding claims, wherein the steps of detecting (501), determining (507) and ascertaining (509) are carried out repeatedly in order to ascertain a temporal progression of the filling level, and with a step of ascertaining a vessel shape (511) of the vessel (112) using the temporal progression of the filling level, and a temporal progression of a volume filled using the beam (225). [9] Device which is designed to carry out and / or control the steps of the method (500) according to one of the preceding claims in corresponding units. [10] Drinks machine (100), in particular a fully automatic coffee machine, having the following features: an outlet comprising at least one nozzle (110) for dispensing a jet (225) of a liquid into a vessel (112); and a device according to claim 6. [11] Vending machine (100) according to one of claims 7 or 8, wherein the device comprises an image recording device (115) which is designed to capture the image (315) which depicts the jet (225), and further comprises an evaluation device (165) which is designed to determine the position of an end of the jet (225) facing away from the nozzle (110) using the image (315), and to determine the fill level of the liquid in the vessel (112) using the position of the end of the jet (225) facing away from the nozzle (110). [12] Vending machine (100) according to claim 11, wherein the image recording device (115) is arranged at a level with the nozzles (110; 210).

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