Household cooking appliance with cooking chamber camera and method of operation

Description

[0001] The invention relates to a household cooking appliance comprising a cooking chamber bounded by a cooking chamber wall and a cooking chamber camera located outside the cooking chamber for capturing images from the cooking chamber through a viewing opening in the cooking chamber wall, wherein the cooking chamber camera is movable by means of the household cooking appliance. The invention also relates to a method for operating such a household appliance. The invention is particularly advantageously applicable to ovens.

[0002] WO 2015 / 185211 A2 discloses a heat treatment monitoring system comprising a heat treatment device, which includes a heat treatment chamber and at least one light source attachment for attaching a light source to illuminate the inside of the heat treatment chamber; and a monitoring device comprising a camera, a camera light source and a mounting part, wherein the mounting part is adapted to be detachably attached to the light source attachment.

[0003] DE 10 2011 002 187 A1 discloses a household appliance with a treatment chamber and a door that closes the treatment chamber. A camera is assigned to the treatment chamber, which is suitable and designed to transmit images captured in the treatment chamber to a display device. To protect the camera in the treatment chamber, particularly in cooking appliances, from excessive heat, a cooling device is preferably arranged next to the camera. Such a cooling device can be provided, for example, by an air supply positioned next to the camera or by other cooling devices, such as a Peltier element.

[0004] WO 2009 / 138359 A2 discloses a household appliance with an image acquisition device, in particular with an internal image acquisition device, and a method for acquiring an internal state or operating state of such a household appliance. A method for reducing thermally induced energy losses in a household appliance that can be opened and closed, in particular a refrigerator or heating appliance with a cavity, comprises the fact that a thermodynamic system is accommodated in the household appliance.

[0005] KR 2016 0069344 A discloses a household cooking appliance in the form of a microwave oven, comprising a cooking chamber bounded by a cooking chamber wall and a cooking chamber camera for capturing images from the cooking chamber, wherein the cooking chamber camera is movable by means of the household cooking appliance between a rest position outside the cooking chamber and a recording position in which it is partially located inside the cooking chamber. The household cooking appliance is configured to move the cooking chamber camera from the rest position to the recording position during an operating cycle and to move it back to the rest position after the recording. In this process, the camera is moved from an electronics compartment outside the cooking chamber into the cooking chamber when a cooking chamber door is opened, so that it protrudes into the cooking chamber, and is moved back into the electronics compartment when the door is closed.If the camera is located in the electronics compartment, an opening in the oven wall, through which the camera is guided, is covered to prevent damage from elevated temperatures and steam. Therefore, the camera cannot take pictures of the oven cavity in its resting position. This arrangement serves to capture images of the oven wall before the start of the cooking process in order to determine its degree of soiling and to keep the camera in its resting position during the cooking process for its protection.

[0006] US 2007 / 246453 A1 discloses a cooking appliance comprising a housing with a burner that heats an object. A first image acquisition unit may be provided on one side of the housing. The first image acquisition unit may be configured to capture image information corresponding to a heat source generated by the burner. Additionally, a display may be provided on one side of the housing to show the image information captured by the first image acquisition unit.

[0007] WO 2018 / 100956 A1 discloses a heating appliance comprising a heating chamber, a camera for capturing the interior of the heating chamber, a storage unit for storing images captured by the camera, a door that opens and closes when an item to be heated is placed in the heating chamber, and a detection unit for detecting the opening and closing of the door. Furthermore, the heating appliance includes a detection unit for extracting heating control information about the item to be heated from an image stored in the storage unit. The detection unit is configured to operate within a predetermined time window before the door is closed. The detection unit is configured to extract the heating control information by selecting a captured image from the images stored in the storage unit within the prescribed time window.

[0008] CN 108 919 721 A discloses a cooking appliance and a control method therefor. The cooking appliance comprises an appliance body with one open end, a door body covering the open end of the appliance body, a camera assembly, and a drive assembly, the appliance body being provided with an inner lining. The door body comprises a door frame, an inner door panel arranged in the door frame, and an outer door panel arranged in the door frame. The inner door panel and the outer door panel are spaced apart. A cavity is formed between the inner door panel and the outer door panel. The inner door panel is made of transparent material; the camera assembly is arranged in the cooking chamber and can project onto food in the cooking chamber through the inner door panel; and the drive assembly is used to drive the camera assembly to move up and down in order to change the height of the camera assembly.

[0009] WO 2016 / 179424 A1 discloses an electric oven, including a series of sensors in the cooking chamber and a processor configured to automatically detect food in the cooking chamber based on sensor measurements and to automatically operate the heating element based on the food identity.

[0010] WO 2012 / 063135 A2 proposes to equip a commercial cooking appliance with a digital optical food recognition device that takes an image of the food.

[0011] US 2014 / 199455 A1 discloses a method for cooking food. The method comprises holding a food item with multiple cooking surfaces, providing a dry steam jet from a steam nozzle, determining a specific subset of the cooking surfaces, and dynamically moving the food item or the steam nozzle so that the dry steam jet is directed precisely onto the desired subset of the cooking surfaces.

[0012] KR 2014 0039733 A discloses a main body in which a cooling roof and an opening section are formed; a door mounted in the opening section of the main body that opens and closes the cooking chamber; and a cooling information collection module mounted in the door that collects cooking information from the inner part of the cooking chamber from the outer part and outputs this information. Furthermore, the temperature of the food can be monitored by collecting this information from the outer part of the cooking chamber and displaying an image of the food and its temperature. The cooking process of the food in the cooking chamber can be monitored in real time without needing to open or close the door.

[0013] It is the TaskThe present invention aims to overcome at least some of the disadvantages of the prior art and, in particular, to provide an inexpensive, easy-to-install, reliable, durable and flexibly adaptable way to take pictures from the cooking chamber of a household cooking appliance.

[0014] This problem is solved according to the features of the independent claims. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0015] The problem is solved by a household cooking appliance having the features of claim 1.

[0016] This appliance has the advantage that, in its resting position, it is well protected from thermal influences from the cooking chamber and is only moved to the more thermally stressed recording position to take an image. In the recording position, the oven camera has a better field of view than in its resting position. Thus, compared to an oven camera permanently positioned in the recording area, the thermal stress is significantly reduced. In particular, with this appliance, the oven camera is not only moved to the thermally more favorable, but optically less favorable, resting position when, for example, a critical oven temperature is reached. Rather, the resting position corresponds to a "normal position" that the oven camera only leaves—and preferably only briefly—to take an image from inside the cooking chamber. Therefore, the oven camera is usually in its resting position most of the time.For example, if a picture is to be taken from the cooking chamber every minute, and taking a picture, including the movement of the cooking chamber camera, takes, say, 12 seconds, the cooking chamber camera will be in its thermally advantageous resting position for 80% of the time. In this recording position, the cooking chamber camera is positioned so close to the viewing window that the window does not, or only minimally, restrict the camera's field of view.

[0017] Compared to cameras that are permanently spaced away from the viewing window and therefore either have a limited field of view or require stationary lenses to maintain a wide field of view, this camera offers the advantage of a wide field of view in its recording position, even without any additional optical elements. This reduces component and assembly costs (e.g., because no adjustment of optical elements is required) and is particularly robust and durable. Furthermore, such a camera system is especially versatile, as it can be quickly and easily adapted to different household cooking appliances.

[0018] A cooking process is understood to be a sequence or procedure for handling food during cooking. Taking pictures from the cooking chamber can then be used, in particular, to determine or monitor the cooking progress of the food inside. For example, the degree of browning and / or changes in volume of the food can be monitored.

[0019] It is further clarification that a household cooking appliance is an oven or includes an oven function (e.g., a stove). The oven may additionally have a microwave function and / or a steam function. However, the household cooking appliance can also be a standalone microwave oven, possibly with at least one additional infrared emitter or resistance heating element. Specifically in the case of an oven, the cooking chamber wall can also be referred to as a muffle.

[0020] It is a further development that the cooking chamber has a loading opening, particularly at the front, which can be closed by means of a door.

[0021] The oven camera can have at least one image sensor, such as a CCD chip. It can have at least one primary optic positioned in front of the image sensor. The primary optic comprises one or more optical elements, e.g., one or more lenses, which are components of the camera and can therefore move with the camera. The oven camera can be a component of a camera module, particularly one that is housed, which may also include camera electronics.

[0022] The viewing window can be located virtually anywhere in the oven wall, e.g., on a left or right side wall, in the ceiling area, at the transition between wall sections, etc. Generally, the appliance can have one or more such oven cameras with differently positioned viewing windows.

[0023] It is a further requirement that the household cooking appliance has at least one drive mechanism for moving the cooking chamber camera, for example, an electric motor, an actuator (e.g., at least one piezo actuator), etc. The cooking chamber camera can interact with one or more guides for its guided movement, e.g., rails or longitudinal grooves. The movement of a drive mechanism, particularly a mechanical one, can be transmitted to the camera, for example, via a suitable force or motion transmission device, possibly with stroke amplification or reduction. The motion transmission device can, for example, include a gear drive, a cable pull, a screw linkage, etc.

[0024] It is a further development that the camera begins taking a picture immediately (i.e., without a specifically planned pause) after reaching the shooting position. It is also a further development that the camera returns to its resting position immediately after taking a picture or a continuous sequence of pictures. This has the advantage of keeping the time spent in the shooting position particularly short, which is thermally beneficial.

[0025] The movement of the camera and the triggering of a picture recording by the camera can be carried out by means of a control unit of the household cooking appliance, in particular a central control unit.

[0026] One design feature is that the oven camera is positioned further away from the oven cavity in its resting position than in its recording position. This makes it particularly easy to implement thermal stress testing of the oven camera in its resting position.

[0027] It is a particularly advantageous design for the simple and compact implementation of the camera movement that the oven camera can move in a straight line between the rest position and the recording position, especially in a tubular channel. The path of the oven camera between the rest position and the recording position is therefore a straight path.

[0028] Alternatively or additionally, the oven camera can be moved laterally so that, in its resting position, it is separated from the oven cavity by the oven wall and, if necessary, by a layer of thermal insulation surrounding the oven wall. The oven camera can be moved laterally only, or it can be moved to a resting position further away from the oven cavity, where it is also laterally offset relative to the viewing window. This can be achieved, for example, by a curved track between the resting position and the recording position. This can offer the additional advantage that the oven camera is rotated relative to the viewing window and thus potentially even better protected against heat radiation passing through the window. For example, the curved track could take the shape of a circular sector or an oval sector.

[0029] One design feature is that the area between the viewing window and the oven camera is free of fixed optical elements. This offers the advantage that the oven camera can be positioned very close to the viewing window in its recording position, thus utilizing a particularly wide field of view. In general, the viewing window itself can also be...

[0030] One design involves covering the viewing opening with an optically transparent cover element. This offers the advantage of better protecting the oven camera from heat (thermal radiation and / or convection heat) that would otherwise pass through the opening from the oven cavity. For further protection against the transmission of thermal radiation or infrared radiation, the cover element can have an IR protective layer (e.g., an IR reflective layer) that is transparent in the visible spectrum but opaque or only slightly transparent to thermal radiation. A further development involves using glass as the cover element, which is advantageously more resistant than, for example, plastic.

[0031] It is a further development that the cover element is designed as a non-radiation-shaping element, for example as a disc.

[0032] It is a further development that the cover element is designed as a beam-shaping optical element, for example, as a lens. This allows the field of view of the oven camera to be further improved with simple means. For example, the cover element can be a lens that widens the field of view of the oven camera. Advantageously, as already explained above, there is no other fixed optical element between the cover element designed as a beam-shaping optical element and the oven camera.

[0033] This design incorporates a closable cover on the household cooking appliance that blocks thermal radiation from entering the oven camera through the viewing window when the oven camera is in its resting position, and allows the oven camera to view the image when it is in the recording position. This further reduces thermal stress on the oven camera when it is in its resting position.

[0034] One embodiment allows the camera to be additionally rotatable or pivotable. This offers the advantage of being able to adjust the camera's orientation in space, particularly in its resting position, thus further reducing its thermal stress. For example, the camera—especially with linear displacement or movement—can be rotated so that thermally less susceptible areas or surfaces are oriented towards the direction of the strongest heat radiation. In a further development, the camera, particularly in this embodiment but not limited to it, can be at least partially coated with a thermal protection layer, such as an IR-reflective layer, a heat-insulating layer, and / or a particularly thermally resistant layer. The camera can then be rotated so that the thermal protection layer is oriented towards the direction of the strongest heat radiation.The thermal protection layer can also be referred to as a heat shield.

[0035] The problem is also solved by a method for operating a household cooking appliance, comprising a cooking chamber bounded by a cooking chamber wall and a cooking chamber camera located outside the cooking chamber for taking pictures from the cooking chamber through a viewing opening in the cooking chamber wall, wherein in the method during a cooking process The oven camera is moved from a thermally less stressed resting position to a thermally more stressed recording position closer to the viewing opening, the oven camera is triggered in the recording position to take a picture and is then moved back from the recording position to the resting position.

[0036] One design involves moving the oven camera from its resting position to the recording position and back again for each image. This advantageously minimizes the time the camera spends in the recording position. Specifically, this design can include the oven camera taking exactly one image in the recording position before returning to its resting position. In other words, the oven camera can be moved from its resting position to the recording position and back for each individual image. However, it is also possible for the oven camera to take a series of images in the recording position before returning to its resting position. Advantageously, there are only short time intervals between individual images in the series. In particular, the images in the series can then be taken immediately one after the other (i.e., without dedicated pauses).

[0037] It is considered advanced training to specify the maximum continuous time ("dwell time") that the oven camera may remain in the recording position, and to move the camera back to its resting position no later than when this dwell time is reached. In advanced training, the dwell time can depend on the set target oven temperature or the measured oven temperature: the higher the temperature, the shorter the maximum dwell time of the oven camera in the recording position. It is also considered advanced training to specify a time ("rest time") for the oven camera in its resting position. This has the advantage of allowing the oven camera a certain amount of time in the resting position to cool down. The resting time can also depend on the set target oven temperature or the measured oven temperature: the higher the temperature, the longer the resting time.

[0038] It is a further development requirement that the oven camera is cooled, at least in its resting position. This can be achieved by providing one or more cooling devices such as cooling air ducts, Peltier elements, etc., in the resting position area.

[0039] One design feature prevents the oven camera from moving into the recording position if a critical oven temperature is detected. This provides an additional safety mechanism to prevent the oven camera from overheating.

[0040] The above-described properties, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an embodiment, which is explained in more detail in connection with the drawings. Fig. 1 shows a sectional view in side view of a section of an oven in the area of ​​an oven camera that can be moved on a straight track; Fig. 2 shows a sectional view in side view of a section of an oven in the area of ​​an oven camera that can be moved on a curved track; and Fig. 3 shows a sectional view in side view of a section of an oven in the area of ​​a conventional oven camera.

[0041] Fig. 3Figure 1 shows a sectional view in side view of a section of a household oven 101 in the area of ​​a conventional stationary oven camera 102. The oven 101 has an oven chamber 103, which is bounded by an oven chamber wall 104, of which a portion of a side wall 105 and a portion of a ceiling 106 are shown. In a transition area between the side wall 105 and the ceiling 106, a viewing opening 107, e.g., circular, is provided in the oven chamber wall 104. The viewing opening 107 is covered by an optically transparent cover element 108, which is designed to prevent the passage of hot air through the viewing opening 107 into an area of ​​the oven 101 facing away from the oven chamber 102.

[0042] The oven camera 102 is located on the side facing away from the cooking chamber, behind the cover element 108. It is fixedly installed in the oven 101 and faces the viewing opening 107. Furthermore, it maintains a significant distance from the cover element 108 for thermal protection. This reduces the thermal stress on the oven camera 102 caused by heat radiation from the cooking chamber 102 passing through the cover element 108 and potentially by heat emitted by the cover element 108 itself.

[0043] Between the oven camera 102 and the cover element 108, there is a fixed intermediate optical element, indicated here by lenses 109 and 110. This has the advantage of allowing the field of view of the oven camera 102, which is limited due to the distance between the oven camera 102 and the cover element 108, to be enlarged. The lenses 109 and 110 can also serve as thermal shielding elements if necessary.

[0044] One disadvantage of the Oven 101 is that lenses 109 and 110 must be adjusted relative to each other and to the oven camera 102 to obtain a sharp image. This, in turn, increases the design and construction time, as well as the installation time and thus the assembly costs. Furthermore, lenses 109 and 110 increase the overall cost of the Oven 101.

[0045] Fig. 1 Figure 1 shows a household cooking appliance according to the invention in the form of an oven 1. The cooking chamber 103 and the cooking chamber wall 104-106 with the viewing opening 107 can be designed as in the oven 101.

[0046] The viewing opening 107 is covered by a transparent cover element in the form of an optically non-beam-shaping or optically neutral glass pane 2. The glass pane 2 may have an optically transparent layer that blocks IR rays (e.g., a reflective layer).

[0047] On the side of the cooking chamber wall 104 facing away from the cooking chamber 103, a camera 3, in the form of a particularly well-housed camera module, is arranged behind the glass pane 2. The camera 3 can, for example, comprise an image sensor 4, electronics for controlling the camera 3 and / or image processing, and / or a lens 5 with one or more optical elements ("primary optics").

[0048] Camera 3 can be automatically moved between a rest position RP, located further away from the viewing aperture 107, and a recording position AP, located close to the viewing aperture 107. In particular, the distance between the lens 5 and the cover plate 2 is minimal in recording position AP, thus providing camera 3 with a particularly large field of view. This is achieved primarily by eliminating the intermediate optics 109, 110 required in oven 101. However, camera 3 is subjected to a significantly higher thermal load in recording position AP compared to the rest position RP. By eliminating the intermediate optics 109, 110, oven 1 is more cost-effective and robust than oven 101.

[0049] To combine particularly low thermal stress on camera 3 with a wide field of view, camera 3 is held in its rest position until an image from the cooking chamber 103 is to be captured. Then, camera 3 is moved to the recording position AP, an image or a rapid sequence of images is captured, and, in particular, immediately afterwards, it is moved back to the rest position RP. The images captured by camera 3 during a cooking process can be used to track developments over time in the cooking chamber 103, for example, to monitor the degree of browning or volume changes of the food during the cooking process.

[0050] Camera 3 is shown here moving in a straight line, specifically perpendicular to the viewing opening 107, as a purely illustrative example. However, camera 3 can alternatively follow, for example, a curved roadway.

[0051] A motor 6, e.g., an electric motor, is provided to move the camera 3. The motor's drive motion is converted into a movement of the camera 3, e.g., by means of a suitable motion system (not shown). The motion system can generally include, for example, a motion transmission device (e.g., a gear drive, a rod drive, a screwed drive rod for a spindle drive, a cable pull, etc.). A guide, particularly a mechanical one, can also be provided to define the path of the camera 3.

[0052] Optionally, the oven 1 can have a baffle 7 that blocks thermal radiation from entering the oven chamber camera 3 through the viewing opening 107 when the oven chamber camera 3 is in the rest position RP.

[0053] In further training, for example by the control unit, if a critical cooking chamber temperature is reached or exceeded, the movement of the cooking chamber camera 3 to the recording position AP can be prevented.

[0054] Fig.2 Figure 8 shows a household cooking appliance according to the invention in the form of an oven 8. The oven 8 is designed similarly to the oven 1, except that the camera 3 is not movable on a straight track between the rest position RP and the recording position AP, as indicated by the double arrow, but on a curved track. This is shown here, purely by way of example, as a ring-sector-shaped track. This has the advantage that the camera 3 can be moved into an area behind a heat insulation 9 facing away from the cooking chamber – which is also present in the oven 1 – and which can advantageously result in a further reduction of the thermal stress on the camera 3.

Claims

1. Household cooking appliance (1) having a cooking chamber (103), delimited by a cooking chamber wall (104 - 106), characterised by a cooking chamber camera (3) located outside of the cooking chamber (103), for capturing images from the cooking chamber (103) through a viewing opening (107) in the cooking chamber wall (104 - 106), wherein - the cooking chamber camera (3) is movable by the household cooking appliance (1) between a resting position (RP) and a capturing position (AP), - the cooking chamber camera (3) is subject to more heat from the cooking chamber in the capturing position (AP) than in the resting position (RP) and - the household cooking appliance (1) is designed to move the cooking chamber camera (3) during an operating sequence, in order to capture an image, from the resting position (RP) into the capturing position (AP) and back into the resting position (RP) after the capture.

2. Household cooking appliance (1) according to claim 1, wherein in the resting position (RP) the cooking chamber camera (3) is moved further away from the cooking chamber (103) than in the capturing position (AP).

3. Household cooking appliance (1) according to one of the preceding claims, wherein the region between the viewing opening (107) and the cooking chamber camera (3) is free of fixed optical elements.

4. Household cooking appliance (1) according to one of the preceding claims, wherein the cooking chamber camera (3) is movable in a rectilinear manner between the resting position (RP) and the capturing position (AP).

5. Household cooking appliance (1) according to one of claims 1 to 3, wherein the cooking chamber camera (3) is movable on a curved track between the resting position (RP) and the capturing position (AP).

6. Household cooking appliance (1) according to one of the preceding claims, wherein the viewing opening (107) is covered by means of an optically transparent cover element (2).

7. Household cooking appliance (1) according to one of the preceding claims, wherein the household cooking appliance (1) has a closable screen (7) which blocks an incidence of thermal radiation through the viewing opening (107) onto the cooking chamber camera (3) when the cooking chamber camera (3) is in the resting position (RP), and opens up a field of view of the cooking chamber camera (3) when the cooking chamber camera (3) is in the capturing position (AP).

8. Household cooking appliance (1) according to one of the preceding claims, wherein the camera (3) is able to be turned.

9. Method for operating a household cooking appliance (1) having a cooking chamber (103), delimited by a cooking chamber wall (104 - 106), and a cooking chamber camera (3) located outside of the cooking chamber (103), for capturing images from the cooking chamber (103) through a viewing opening (107) in the cooking chamber wall (104 - 106), wherein in the method, during an operating sequence - the cooking chamber camera (3) is moved from a resting position (RP) subject to less thermal stress, into a capturing position (RP) located closer to the viewing opening (107) and subject to greater thermal stress, - the cooking chamber camera (3) is triggered to capture an image in the capturing position (AP) and then - is moved from the capturing position (AP) back into the resting position (RP).

10. Method according to claim 9, wherein for each capture of an image the cooking chamber camera (3) is moved from the resting position (RP) into the capturing position (AP) and back into the resting position (RP).

11. Method according to one of claims 9 to 10, wherein when it is established that a critical cooking chamber temperature is reached or exceeded, a movement of the cooking chamber camera (3) into the capturing position (AP) is prevented.

12. Method according to one of claims 9 to 11, in which a dwell time, in which the cooking chamber camera (3) is permitted to stay for a maximum time uninterrupted in the capturing position (AP) and the cooking chamber camera (3) is moved back into the resting position (RP) at the latest when this dwell time is reached.

13. Method according to claim 12, in which the dwell time is dependent on the adjusted target cooking chamber temperature or the measured cooking chamber temperature.

14. Method according to one of claims 9 to 13, in which a resting duration of the cooking chamber camera (3) in its resting position (RP) is predetermined.