OPERATION OF A HOUSEHOLD COOKING APPLIANCE WITH AT LEAST ONE CAMERA

Abstract

In a method for operating a household cooking appliance, a camera records a pixel-based image from a cooking chamber of the household cooking appliance. The image is evaluated with exclusion of brightness values of associated pixels thereof.

Claims

12.-22. (canceled)

12. A method for operating a household cooking appliance, said method comprising the steps of: (a) recording with a camera a pixel-based image from a cooking chamber of the household cooking appliance; and (b) evaluating the image with exclusion of brightness values of associated pixels thereof.

13. The method of claim 12, wherein the image is evaluated by generating a brightness-normalized image from the recorded image, with the brightness values of the associated pixels being removed, and by evaluating the brightness-normalized image.

14. The method of claim 13, wherein the brightness-normalized image is generated from an image having pixels which each have a plurality of color space coordinates including a brightness coordinate, by removing the brightness coordinate.

15. The method of claim 13, wherein the brightness-normalized image is generated from an HSX image.

16. The method of claim 12, wherein the pixels of the pixel-based image do not have a separate brightness coordinate, and further comprising converting the pixel-based image into an image having pixels which each have a plurality of color space coordinates including a brightness coordinate.

17. The method of claim 13, wherein the recorded image is an RGB image, and further comprising: converting the RGB image into an HSX image; and generating the brightness-normalized image from the HSX image by removing the brightness values.

18. The method of claim 13, wherein the brightness-normalized image is evaluated using a remaining color coordinate for determining a degree of cooking of food to be cooked and illustrated in the recorded image.

19. The method of claim 13, wherein the degree of cooking is a degree of browning of the food to be cooked and illustrated in the recorded image.

20. The method of claim 18, further comprising determining a reaching of a target degree of cooking of the food to be cooked by reaching a target color point of the food to be cooked which target color point is defined by the remaining color coordinate or an environment thereof.

21. The method of claim 12, wherein the steps (a) and (b) are repeatedly carried out chronologically in succession and color coordinates of a food to be cooked are evaluated chronologically in succession for determining a target degree of cooking of the food to be cooked and/or a remaining cooking time.

22. The method of claim 21, further comprising evaluating a curve progression of a color coordinate for determining the target degree of cooking of the food to be cooked and/or the remaining cooking time.

23. A household cooking appliance, comprising: a cooking chamber; a camera for recording pixel-based images from the cooking chamber; and a control apparatus connected to the camera and configured to evaluate the image with exclusion of brightness values of associated pixels thereof.

24. The household cooking appliance of claim 23, wherein the image is evaluated by generating a brightness-normalized image from the recorded image, with the brightness values of the associated pixels being removed, and evaluating the brightness-normalized image.

25. The household cooking appliance of claim 24, wherein the brightness-normalized image is generated from an image having pixels which each have a plurality of color space coordinates including a brightness coordinate, by removing the brightness coordinate.

26. The household cooking appliance of claim 24, wherein the brightness-normalized image is generated from an HSX image.

27. The household cooking appliance of claim 23, wherein the pixels of the pixel-based image do not have a separate brightness coordinate, and the pixel-based image are converted into an image having pixels which each have a plurality of color space coordinates including a brightness coordinate.

28. The household cooking appliance of claim 24, wherein the recorded image is an RGB image which is converted into an HSX image, with the brightness-normalized image being generated from the HSX image by removing the brightness values.

29. The household cooking appliance of claim 24, wherein the brightness-normalized image is evaluated by the control apparatus using at least one remaining color coordinate for determining a degree of cooking of food to be cooked and illustrated in the recorded image.

30. The household cooking appliance of claim 29, wherein reaching a target degree of cooking of the food to be cooked is determined by reaching a target color point of the food to be cooked which target color point is defined by the remaining color coordinate or an environment thereof.

31. The household cooking appliance of claim 23, wherein the camera is configured to repeatedly record pixel-based images chronologically in succession, said control apparatus evaluating color coordinates of a food to be cooked chronologically in succession for determining a target degree of cooking of the food to be cooked and/or a remaining cooking time.

32. The household cooking appliance of claim 31, wherein the control apparatus is configured to evaluate a curve progression of at least one of the color coordinates for determining the target degree of cooking of the food to be cooked (A) and/or a remaining cooking time.

Description

[0048] The above-described properties, features and advantages of this invention and the manner in which they are achieved will become clearer and more easily understood in connection with the following schematic description of an exemplary embodiment which is described in more detail in connection with the drawings.

[0049] FIG. 1 shows as a sectional view in side view a sketch of a household cooking appliance with at least one camera;

[0050] FIG. 2 shows the plotting of an average value of the different color space coordinates of an HSV image of a white reference as a function of an insertion height;

[0051] FIG. 3 shows a standard deviation for the different color coordinates of an HSV image of a white reference as a function of an insertion height;

[0052] FIG. 4 shows a curve progression of standardized color coordinates of an HSV image of a food to be cooked over a duration of a cooking operation; and

[0053] FIG. 5 shows a method sequence for preparing an evaluation of a recorded image for operating the household cooking appliance.

[0054] FIG. 1 shows as a sectional view in side view a sketch of a household cooking appliance 1 with a cooking chamber 2, the front-side loading opening 3 thereof being closable by means of a cooking chamber door 4. The cooking chamber 2 has a plurality of insertion levels with the corresponding insertion heights EH1 to EH4, wherein the insertion height EH1 is in the vicinity of a bottom of the cooking chamber 2 and the insertion height EH4 is in the vicinity of a ceiling of the cooking chamber 2. Here the food to be cooked A, which itself is at a certain height, is placed at the second insertion height EH2, for example on an oven rack or baking sheet (not shown) inserted in the associated insertion level.

[0055] A color camera 5 is attached to the ceiling of the cooking chamber 2, however different cameras (not shown) may also be present. The color camera 5 is designed (i.e. configured and arranged) to record pixel-based color images from above or from obliquely above from the cooking chamber 2.

[0056] The household cooking appliance 1 also has at least one lighting apparatus for illuminating the cooking chamber 2, for example having a spotlight (for example LED spotlight) 6 in the region of the ceiling and a spotlight (for example LED spotlight) 7 in the region of the left-hand and/or right-hand side wall of the cooking chamber 2. The brightness distribution produced during the operation of the spotlights 6, 7 is non-homogenous in the horizontal plane due to the light cone thereof in the cooking chamber 2 and is also dependent on the measured height in the cooking chamber 2. Overall in the cooking chamber a non-homogenous light distribution is produced in all three spatial directions.

[0057] The color camera 5 and the spotlights 6, 7 are connected to a control apparatus 8 which may also be designed as a data evaluation apparatus.

[0058] The control apparatus 8 may also be connected to a communication module 9 (for example an Ethernet module, a WLAN module, etc.) and via the communication module 9 for example via a network N to a computer C which is external to the appliance. As a result, it is possible to outsource data processing operations or computing capacity entirely or partially from the household cooking appliance 1, for example in order to retain it in the so-called cloud.

[0059] FIG. 2 shows the plotting of an average value of the pixel-related values for the different color space coordinates or channels H (color value), S (saturation) and V (brightness) of an HSV image of a white reference as a function of the insertion heights EH1 to EH4. The color coordinates H, S and V here are normalized to a maximum value of “1” as follows: the color value H is normalized to 360° (a normalized color value H=0 thus corresponds to a color angle of 0° or 360°, a color value of 0.5 corresponds to a color angle of 180°, etc.) whilst the color space coordinates S and V are normalized to 100% (thus a normalized value of 0.5 corresponds to a saturation of 50% or a brightness of 50%, etc.).

The HSV image may be recorded directly or indirectly (for example via an RGB image).

[0060] The average values relating to the pixels or the area of the white reference of the H and S channels H, S are approximately constant for the insertion levels EH1 to EH4, whilst the V channel V significantly changes.

[0061] FIG. 3 shows a standard deviation for the different color coordinates or channels H, S, V of the HSV image of FIG. 2 as a function of the insertion heights EH1 to EH4. The standard deviation in the V channel V is substantially greater than in the H and S channel H, S. This means that the H and S values of the individual pixels are approximately constant within the area of the white reference at the respective insertion heights EH1 to EH4.

[0062] A browning assessment of the food to be cooked A by considering the brightness is consequently very susceptible to error, in particular when the insertion height EH1 to EH4 and the height and shape of the food to be cooked are not known.

[0063] FIG. 4 shows a curve progression of the normalized color coordinates H and S similar to FIG. 2 of an HSV image of an upper side of a food to be cooked A in the form of a mozzarella-type pizza over a time t of an oven operation in seconds.

[0064] From approx. t=800 s the values for H (lower curve) and V (upper curve) start to change significantly, and namely H reduces and S rises. The curves or curve progressions after t approx. 1200 s then transition into a respective plateau state. This change of H and S corresponds to a browning of the surface of the pizza, so that the browning may also be reliably identified without considering the brightness value S.

[0065] From the curves or curve progressions for H and S it is possible to determine when a target degree of cooking and/or remaining cooking time has been reached. If, for example, the time until the start and/or the finish of the browning is known, then the time before the target degree of cooking and/or remaining cooking time is reached may be looked up by means of, for example, experimentally determined tables or characteristic curves.

[0066] FIG. 5 shows a method sequence for preparing an evaluation of an RGB image 10 recorded in a step S1 by the camera 5 for operating the household cooking appliance 1. For example, in order to reduce the susceptibility to error during the browning assessment, the brightness information which is highly susceptible to error is omitted or excluded from further evaluation.

[0067] To this end, in a step S2 the recorded RGB image 10 with its channels R (red), G (green) and B (blue) is converted or transformed into an HSV image 11 with its channels H, S and V.

[0068] In a step S3 the V channel is separated, resulting in a brightness-normalized HS image 12, the quantity of data thereof being less by approx. a third than that of the HSV image 11. The V channel V is thus not used in step S4 for further evaluation, as indicated by being crossed out.

[0069] The steps S3, S3 and/or S4 may run entirely or partially on the control apparatus 8 and/or on the computer C.

[0070] Naturally, the present invention is not limited to the exemplary embodiment shown.

[0071] Generally “a”, “an”, etc. may be understood to mean a singular or a plural, in particular in the sense of “at least one” or “one or more” etc. provided this is not explicitly excluded, for example by the expression “exactly one”, etc. Numerical indicator may also encompass precisely the specified number and a conventional tolerance range, provided this is not explicitly excluded.

LIST OF REFERENCE CHARACTERS

[0072] 1 Household cooking appliance [0073] 2 Cooking chamber [0074] 3 Loading opening [0075] 4 Cooking chamber door [0076] 5 Color camera [0077] 6 Spotlight [0078] 7 Spotlight [0079] 8 Control apparatus [0080] 9 Communication module [0081] 10 RGB image [0082] 11 HSV image [0083] 12 Brightness-normalized HS image [0084] A Food to be cooked [0085] B B-channel [0086] C Computer [0087] EH1-EH4 Insertion height [0088] G G-channel [0089] H H-channel [0090] N Network [0091] R R-channel [0092] S S-channel [0093] V V-channel