OPERATING A COOKING APPLIANCE

Abstract

In a method for operating a cooking appliance, a cooking compartment is irradiated by light of different wavelength ranges. Light reflected in the cooking compartment is measured and measurement results of the light measurement are spectroscopically evaluated. Depending on a result of the spectroscopic evaluation, operation of the cooking appliance is adjusted.

Claims

1-15. (canceled)

16. A method for operating a cooking appliance, said method comprising: irradiating a cooking compartment by light of different wavelength ranges; measuring light reflected in the cooking compartment; spectroscopically evaluating measurement results of the light measurement; and adjusting an operation of the cooking appliance depending on a result of the spectroscopic evaluation.

17. The method of claim 16, wherein the light of different wavelength ranges is irradiated temporally serially into the cooking compartment.

18. The method of claim 16, wherein the spectroscopic evaluation is implemented by determining intensity relationships of the measurement results.

19. The method of claim 18, wherein the measurement results are spectroscopically evaluated so that variations over time of the intensity relationships are determined.

20. The method of claim 16, further comprising captivating the light reflected in the cooking compartment on a pixel basis by a camera, with the spectroscopic evaluation being implemented to spectroscopically evaluate measurement results for each of several groups of pixels.

21. The method The method of claim 20, wherein the measurement results are spectroscopically evaluated for each pixel.

22. The method of claim 20, further comprising carrying out an object recognition by the camera, with the spectroscopic evaluation being performed depending on a type of recognized object.

23. The method of claim 22, wherein the operation of the cooking appliance is adjusted depending on the result of the spectroscopic evaluation of the object detected by the object recognition and a result of an object evaluation of the object detected by object recognition.

24. The method of claim 16, wherein light reflected diffusely in the cooking compartment is measured.

25. The method of claim 16, wherein at least one of the wavelength ranges of the light is an infrared wavelength range.

26. The method of claim 25, wherein the infrared wavelength range is a near-infrared range.

27. The method of claim 16, wherein the wavelength ranges have at least one red range, one green range and one blue range.

28. A cooking appliance, comprising: a cooking compartment; a light source configured to radiate light into the cooking compartment; a light sensor configured to measure light reflected in the cooking compartment; an evaluation device configured to execute a spectroscopic evaluation of measurement results determined by the light sensor; and a control device configured to manage a cooking sequence depending on a result of the spectroscopic evaluation.

29. The cooking appliance of claim 28, further comprising several light sources configured to generate light of different wavelength ranges, said cooking appliance being set up to actuate the light sources temporally serially.

30. The cooking appliance of claim 28, wherein the light source is configured to generate light of different IR wavelength ranges.

31. The cooking appliance of claim 29, wherein two of the light sources generate light of different IR wavelength ranges.

32. The cooking appliance of claim 28, wherein the light sensor includes a camera.

33. The cooking appliance of claim 32, wherein the camera is configured to captivate the light reflected in the cooking compartment on a pixel basis.

34. The cooking appliance of claim 32, wherein the camera is linked to the evaluation device for object recognition.

Description

[0052] The above-described properties, features and advantages of this invention and the manner in which these are achieved will now be described more clearly and intelligibly with an exemplary embodiment, illustrated in the following schematic description of an exemplary embodiment, which will be described in detail making reference to the drawings.

[0053] FIG. 1 shows an inventive household appliance; and

[0054] FIG. 2 shows a possible sequence for operating the household appliance.

[0055] FIG. 1 shows a household cooking appliance in the form of an oven 1 at least with a steam cooking functionality. For this purpose the oven 1 has a cooking compartment 2 which can be heated using at least one heating device 3. Steam can be applied to the cooking compartment 2 using a steam generation device 4. Food to be cooked G, which is housed in an item of cookware in the form of a dish S, can be inserted in the cooking compartment 2. The dish G is placed on a baking tray B.

[0056] The oven 1 furthermore has several light sources in the form of several LEDs 6 inserted behind the cooking compartment wall or oven muffle 5. The LEDs 6 each generate light in different wavelength ranges and essentially at least red, green and blue light as well as near-infrared light in at least two wavelength ranges. At least five LEDs 6 are therefore available which can be actuated separately per wavelength range. The LEDs 6 are in particular arranged behind the oven muffle 5, wherein the light of which falls into the cooking compartment 2 via at least one opening of the oven muffle 5. The at least one opening can be covered by a viewing window (not shown).

[0057] The oven 1 also has a light sensor in a ceiling of the oven muffle 5 in the form of a camera 7. A field of view F of the camera 7 is set up vertically here purely by way of example and comprises in this instance parts of the oven muffle 5 as well as the baking tray B with the dish S placed upon it. The camera 7 is set up so as not to receive directly any light emitted from an LED 6 and also no reflection reflex at the oven muffle 5. The camera 7 therefore receives and measures practically only diffusely reflected scattered light. Should however specularly reflected light fall into the camera 7, such a reflection reflex can be detected and suppressed (e.g. hidden).

[0058] The camera 7 is connected to a control device 8. The control device 8 is used to control the oven 1, for example to control cooking programs and can therefore for example actuate the heating device 3 and the steam generation device 4. The control device 8 can also actuate the LEDs 6 and the camera 7 and is also used to evaluate the measurement results (images) determined by the camera 7, and namely for object recognition, object evaluation and spectroscopic evaluation. The control device 8 synchronizes among other things the emission of light or light pulses by the LEDs 6 and the image recording by the camera 7 so that the light pulses can be uniquely assigned to the images.

[0059] For example the LEDs 6 can be actuated using the control device 8 such that they emit light pulses into the cooking compartment 2 sequentially (temporally serially). The camera 7 is sensitive for all wavelengths and captures a respective image for each LED 6 or for each of the light pulses. The image is constructed on a pixel basis and has a resolution for example of 512512 or 20481024 pixels.

[0060] In particular red, green and blue images can be combined into a white image. Using the white image an object recognition can be performed using the control device 8, for example the food to be cooked G, the dish S, the baking tray B and parts of the side wall of the oven muffle 5 can be recognized.

[0061] Using the control device 8 the pixels can be spectroscopically evaluated individually, particularly whereby their wavelength-dependent intensities are compared with each other. Additionally or alternatively the variations over time of the intensities and/or intensity relationships can be determined and evaluated.

[0062] In this context different objects recognized as a result of image recognition in particular can be separated or spectroscopically evaluated in a variety of ways. For example a container in which food is be cooked (here: the dish S) can be recognized as a plastic dish using object recognition, object evaluation and/or spectroscopic evaluation. For example the oven 1 can issue a warning notice to a user. The warning notice can for example not be issued if the material of the dish is recognized as stoneware or porcelain. A warning can be issued relating to metallic containers in which food is to be cooked prior to a microwave radiation etc.

[0063] Object recognition, object evaluation and/or spectroscopic evaluation of the food to be cooked G can also be used to detect a degree of browning, e.g. optically as a result of a color change to darker colors and/or spectroscopically by detecting chemical processes taking place during browning. As a result of such an object recognition and/or spectroscopic evaluation a cooking compartment temperature can be adjusted for example and if applicable a cooking sequence can also be terminated.

[0064] Using object recognition and/or spectroscopic evaluation of the oven muffle 5, the degree of soiling of said oven muffle can be determined. The degree of soiling can be detected using object recognition or object evaluation based on a change in the degree of diffuse reflection compared to a clean surface. The soiling can be detected using spectroscopic evaluation by the presence of typical soiling substances such as fat. This can be applied in the same way to the baking tray B or a baffle which is not shown. This detection of the degree of soiling can for example be used to issue a note to a user regarding cleaning the cooking compartment, e.g. to carry out a pyrolytic or catalytic self-cleaning.

[0065] A presence and a concentration of steam in the cooking compartment 2 can also be determined using spectroscopic evaluation. This allows the addition of steam into the cooking compartment to be precisely controlled.

[0066] In particular the combination of object recognition (and object evaluation) and/or spectroscopic evaluation can significantly increase the recognition accuracy, for example can also improve object recognition.

[0067] FIG. 2 shows a possible sequence for operating a household cooking appliance using the oven 1.

[0068] In a first step S1 the LEDs 6 are actuated so that they emit light pulses successively with different wavelength ranges (e.g. red, green, blue and twice near-infrared) into the cooking compartment 2, and namely with individual wavelength ranges and/or as a mixture of different wavelength ranges. In this way in particular a measurement surface common to the LEDs 6 can be illuminated.

[0069] In a second step S2 images of the cooking compartment 2 are captured using the camera 7, and namely at least one image for each wavelength range. The image detects light reflected from the cooking compartment 2. This can be light reflected on the measurement surface and/or in the atmosphere of the cooking compartment, in particular diffusely reflected light.

[0070] In a third step S3 an object recognition is performed using one of the images or a combination of images (e.g. a white light image compiled from red, green and blue light portions).

[0071] In a fourth step S4 an object evaluation of the objects detected in the image or images is performed.

[0072] In a fifth step S5 a spectroscopic evaluation of the objects detected in the image or images is performed, if applicable also as a temporal sequence together with previously captured images. This evaluation can in particular be performed individually for each pixel.

[0073] In a sixth step S6 the optical evaluation and the spectroscopic evaluation are evaluated on a combined basis in order to obtain a result based on both evaluations or assessments.

[0074] In a seventh step S7 the oven 1 is operated depending on a result of a combined evaluation.

[0075] Naturally, the present invention is not restricted to the exemplary embodiment disclosed.

[0076] In this way instead of being on the ceiling of the cooking compartment the light sensor can also be positioned on another wall of the cooking compartment, in particular in one of the corners of the cooking compartment or in the door.

[0077] In general, a, an, etc. can be understood as singular or plural, in particular in the sense of at least one or one or more, etc., provided this is not explicitly excluded, e.g. by the expression exactly one, etc.

[0078] A numerical value can also include the given value as a typical tolerance range, provided this is not explicitly excluded.

LIST OF REFERENCE CHARACTERS

[0079] 1 Oven [0080] 2 Cooking compartment [0081] 3 Heating device [0082] 4 Steam generation device [0083] 5 Oven muffle [0084] 6 LED [0085] 7 Camera [0086] 8 Control device [0087] B Baking tray [0088] F Field of view [0089] G Food to be cooked [0090] S Dish [0091] S1-S7 Method steps