DE102016107617A1 - Method for operating a cooking appliance and cooking appliance - Google Patents

Abstract

The present invention relates to a method for operating a cooking appliance (1) and a cooking appliance (1) with a heated cooking chamber (2) for the preparation of food (3). The heating of the cooking chamber (2) is adjusted by a control device (4). The control device (4) takes into account a characteristic of the food (3) parameters. To determine the parameter, the food to be cooked (3) is detected with a camera device (5). In this case, the food (3) for generating a shadow (6) is illuminated by means of a lighting device (7). The shadow (6) thrown by the food (3) is detected by the camera device (5). Based on the detected shadow (6), the parameter characteristic of the food to be cooked (3) is determined by an evaluation device (8).

Description

The present invention relates to a method for operating a cooking appliance and a cooking appliance with at least one heatable cooking chamber for the preparation of food. The heating of the cooking chamber is adjustable by at least one control device.

For an optimal cooking result, it is usually crucial to consider certain properties of the food. Such information about the food to be cooked is particularly important for a reliable sequence of automatic programs. For example, for a tasty preparation of a roast in an oven by means of an automatic function should be considered how big this roast is.

One way to provide this information to the cooking appliance is by the user. For example, a specific food can be specified in a preselection. With such a preselection automatic can be achieved basically good results. However, each food usually also has individual properties, so that it may lead to deviations from the food taken into account in the automatic preselection. For example, roast pieces often differ in terms of their dimensions or their volume.

It is therefore advantageous if certain properties of the food can be automatically detected and taken into account by the cooking appliance. In the prior art, therefore, cooking appliances have become known which detect and evaluate the food by means of a camera device.

The camera usually delivers a two-dimensional image, from which particularly decisive parameters can not be determined, such as the size and the geometry of the food. However, the size and the geometry of the item to be cooked represent particularly decisive features of the item to be cooked, which decisively influence the preparation parameters within an automatic program.

Furthermore, camera techniques have become known for detecting three-dimensional quantities, in which an object is detected by means of two or more cameras or a stereo camera. Examples are in https://de.wikipedia.org/wiki/3D-Kamera called. However, such systems are usually very expensive. In addition, the integration of such camera systems in a cooking appliance requires a very complex and costly design implementation.

It is therefore the object of the present invention to provide a method for operating a cooking appliance and a cooking appliance, which enable an improved characterization of a cooking product by means of a camera device.

This object is achieved by a method having the features of claim 1 and a cooking appliance having the features of claim 12. Preferred features are the subject of the dependent claims. Further advantages and features will become apparent from the general description of the invention and the description of the embodiments.

The inventive method is used to operate a cooking appliance. The cooking appliance comprises at least one heatable cooking space for the preparation of food. The heating of the cooking chamber is adjusted by at least one control device. The control device takes into account at least one characteristic of the food to be cooked parameters. To determine the parameter, the food to be cooked is detected at least partially with at least one camera device. In this case, the food to be cooked is at least partially illuminated by at least one illumination device in order to produce at least one shadow. The shadow thrown by the food to be cooked is detected by the camera device. On the basis of the detected shadow is determined by at least one evaluation of the characteristic of the food to be cooked parameters. Under Gargut in the sense of the patent application is to be cooked food to understand, but also the food received from a food container, for example in the form of a cake pan or a casserole, or even only the food containers without the food ..

The method according to the invention offers many advantages. A significant advantage is that the characterization of the food is done by means of a shadow. As a result, it is possible to extract particularly valuable information from the two-dimensional image, which was captured by the camera device. For example, the height and / or a geometric shape of the food can be determined. It is particularly advantageous that no complex camera technology is necessary to gain this information about the food. In particular, no expensive and expensive stereo cameras or camera systems with multiple cameras or multiple lenses are necessary. Another particular advantage of the invention is also that the shadow is achieved by lighting by means of a lighting device, ie, existing device components are used. As a result, a particularly meaningful and targeted shadowing of the food can be achieved. Thus, a special reliable and reproducible determination of the characteristic parameter of the food to be made on the basis of the detected shadows.

It is particularly preferred that a volume and / or a shape of the food are determined as a characteristic parameter. It is also possible that a type of food is determined, for example, it can be distinguished between pasta and pieces of meat. It is also possible that a surface texture of the food is determined as a characteristic parameter. For determining the volume and / or the shape of the food, the height and / or the diameter and / or the side length of the food are determined in particular. Such parameters can be determined particularly well by the shadow cast and also provide particularly crucial information about the food to be cooked. As a result, a particularly reliable control of automatic programs is possible, so that the cooking result can be significantly improved.

On the basis of the characteristic parameter, in particular the power input of the heating is set. For example, the duration and / or timing of the heating can be adjusted. It is also possible that a program selection and / or program adaptation takes place on the basis of the characteristic parameter. For example, depending on the height of the food, the cooking duration of a program can be extended or shortened.

It is particularly preferred that the food to be cooked is placed on a food support in the cooking chamber. In this case, an insertion position of the food support in the cooking chamber is preferably determined. This has the advantage that with knowledge of the insertion position and, for example, the insertion height, a particularly reliable evaluation of the shadow cast can take place. The insertion position is characterized in particular by the insertion height, which denotes the height of the food support over a cooking chamber floor. The insertion position preferably characterizes the distance of the food support to the camera device in the cooking chamber.

In this case, at least one sensory detection of the insertion position can be performed. For example, corresponding sensors can be arranged on a food support holder.

It can also be provided that a required insertion position is specified via a user interface. For this purpose, for example, in a display of the cooking appliance specified that the food support is to be inserted in a certain rack level. In this case, this insertion level is taken only for detecting the characteristic parameter. Possible and preferred, however, is that the food support remains in this insertion position during the cooking process. For this purpose, it can be provided that the requested insertion position is monitored by sensors. Upon detection of an incorrect insertion position, for example, at least one message can be output to the user.

To detect the insertion position of the food support in the cooking chamber is also possible that the used insertion position is queried via at least one user interface. Then the user can enter via the user interface, in which slot height the food support is located. A sensory check of the insertion height is possible.

To determine the insertion position of the food support in the cooking chamber is also possible that the information recorded with the camera device information is evaluated. Based on this information, preferably a calculation of the distance of the food support to the camera device. Based on this distance, the insertion position of the food support in the cooking chamber is preferably determined. These embodiments provide a particularly reliable and inexpensive determination of the insertion position of the food support.

The method preferably comprises at least one method step in which the food to be cooked is specifically and uniformly illuminated by the illumination device. In particular, the evenly illuminated food is detected by the camera device. The uniform illumination is used in particular for detecting a possible shadowless lit garnish. As a result, a shadow-free reference image of the food can be detected particularly well. This reference is preferably stored in the evaluation and used by this, in order to recognize the cast in certain lighting situations shadow of the food can. Preferably, such shadow-free illumination also serves to detect a reference of the rack level and / or the food support.

Such a shadow-free illumination is preferably carried out by an illumination of the food from opposite sides of the cooking chamber. Possible and preferred is also a lighting from different heights of the oven. In this case, preferably at least two light sources and particularly preferably a plurality of light sources are used. The light sources are switched on in particular at the same time. As far as a regulation of the intensity of the light sources is provided, the intensity of the light sources is set correspondingly high. Such lighting with multiple light sources from multiple positions is also possible a larger and / or complex shaped food 3 illuminate evenly and as shadow-free as possible.

In all embodiments of the method, it is preferred that the food to be cooked is lighted uniquely with the illumination device of at least two sides of the cooking chamber. Preferably, the food to be cooked is uniquely illuminated even from at least two different heights of the cooking chamber. In this case, the shadow cast by the food to be cooked is preferably detected by the camera device. Such an uneven illumination of the food can produce a particularly intense shadow, from which important information about the food can be found. In particular, different lighting situations are set over time. In each case, a detection of the food and the shadow with the camera device is preferably carried out in each lighting situation. Particular preference is given to a bundled and / or point illumination from a certain height of the cooking chamber and / or from a specific side of the cooking chamber.

Preferably, individual light sources of the illumination device are selectively switched off and / or switched on at different positions in the cooking chamber. It is also possible that the light sources are adjusted in intensity. Thus, a particularly targeted lighting of the food can be achieved with a correspondingly intense shadow. The light sources are preferably arranged at different heights of the cooking chamber. In particular, the light sources are also arranged on different sides and preferably on opposite sides of the cooking chamber. In particular, at least two light sources and preferably a plurality of light sources are switched on and / or off. Preferably, light sources are switched on and / or off together, which are arranged at the same height on different sides of the cooking chamber. The respective shadows are preferably recorded and evaluated. Upon a renewed switching on and / or switching off the light sources, the respective shadows are preferably recorded and evaluated again. In particular, the characteristic parameter of the cooking product is calculated from a change of the shadows. The control of the light sources is preferably carried out by the evaluation device.

It is possible that, based on the information acquired with the camera device, a check is made as to whether the shadows of the food to be analyzed lie within a detection range of the camera device. In particular, a check can be made as to whether the shadows do not go beyond the food support, if this is used as a reference for the evaluation. It can thereby be ensured that the shadows cast by the food to be cooked are completely detected and thus a reproducible determination of the characteristic parameter of the food is possible.

It is possible that a detection of the shadows in another lighting situation is provided if the shadows are not within the detection range of the camera device. For this purpose, for example, other light sources and particularly preferably light sources are used at a different height. If the shadows are not within the detection range of the camera device, a message can also be output via a user interface. For example, the user is then asked to insert the food support in another insertion position.

It is possible and preferred that on the basis of the information acquired with the camera device, a check is made as to whether the detected shadows of the food have a contrast range necessary for the evaluation. If the contrast range is insufficient, further detection is preferably carried out with the camera device in the event of a changed lighting situation. For example, further and / or other light sources can be switched on purposefully. It is also possible that the intensity of the light sources and / or the bundling of the light sources is adjusted. It can also be done an adjustment of the contrast extent in the context of image processing. Such a control of the contrast range allows the shadows to be particularly well recognized and reliably evaluated.

In all embodiments, it is also preferred that an expansion of the shadow detected by the camera device is determined by means of the evaluation device. Preferably, a shape and / or a height of the food is calculated on the basis of the extent of the shadow. Particularly preferably, shadows detected in different lighting situations and, for example, in lighting with light sources from different heights of the cooking chamber are evaluated. The shadows are compared in particular. On the basis of a change in the shadows in relation to the respective lighting situations, the shape and / or the height of the food is then preferably calculated. Such a change of the shadow as a function of the lighting situation is particularly dependent on the height or the shape of the food and can therefore be used particularly well for a calculation of the characteristic parameter. The height of the food can also be determined by capturing and evaluating only one shade.

In particular, a distinction between detected shadow and food and / or food support is provided, for example in the context of an image analysis by means of the evaluation. Particularly preferably, the real extent of the area detected in the image is known. For example, the shelf level and / or the food support is taken as a reference. Based on this reference, the real extent of the shadows is then preferably determined. This can be done for example by determining the real extent of a pixel or pixel. The shadow then corresponds for example to a part of the area detected in the image and can thus be calculated from the known real extent of the pixel or pixel.

Preferably, by means of the evaluation device, a two-dimensional extent of the cooking product detected by the camera device is determined. Based on the two-dimensional extent and the height of the food, the volume of the food is preferably determined. The volume is a particularly important parameter of the food and can be considered particularly advantageous in the control of device functions. For example, depending on the volume, the heating of the cooking chamber is set by the control device. The two-dimensional extent of the food preferably corresponds to a part of the area detected in the image and can thus be calculated from the known real extent of the image. In this case, a distinction is preferably made between food to be cooked and shadow and / or food support in the context of an image analysis by the evaluation. The two-dimensional extent comprises in particular the width and / or length of the food. It can also be calculated a diameter, for example, in an approximately round or circular food.

It is preferred that the detection of the shadow with the camera device and the determination of the characteristic parameter by the evaluation device are performed at least once before the start of a cooking process. As a result, the cooking process can be optimally adapted to the food to be cooked. In addition to or instead of the implementation before the start of the cooking process, at least once during a cooking process and / or at least once after a cooking process, a detection of the shadows and a determination of the characteristic parameter can take place. As a result, for example, the cooking progress can be monitored during the cooking process and the remaining cooking time can be adjusted. In a determination of the parameter after the cooking process, for example, an evaluation of the cooking result can be carried out. Thus, for further cooking operations, an adjustment of operating parameters can be made.

The cooking appliance according to the invention is particularly suitable and designed to be operated according to the inventive method. The cooking appliance comprises at least one heatable cooking space for the preparation of food. The heating of the cooking chamber is adjustable by at least one control device. The control device is suitable and designed to take into account at least one parameter characteristic of the food to be cooked. At least one camera device is provided for determining the parameter. The camera device is suitable and designed to at least partially detect the food to be cooked. In this case, the camera device is associated with at least one illumination device with at least two separately controllable light sources. The lighting device is suitable and designed to selectively illuminate the food to produce at least one shadow. The camera device is suitable and designed to detect the shadow cast by the food to be cooked and to provide at least one evaluation device. The evaluation device is suitable and designed to determine the parameters characteristic of the product to be cooked on the basis of the detected shadow.

The cooking appliance according to the invention also offers many advantages. A particular advantage is that the cooking appliance comprises a lighting device with which a targeted shadowing of the food can be generated. By recording and evaluating such a shadow can be important features of the food and z. B. determine its volume. The features can be taken into account by the control device in the heating of the cooking chamber, so that particularly tasty cooking results can be achieved with the cooking appliance according to the invention.

The evaluation device is particularly suitable and designed to distinguish from the information provided by the camera device between shadow and food to be cooked and / or food support. In particular, the camera device is suitable and designed to detect light in the visible wavelength range. Also possible are other wavelength ranges, for example in the infrared range.

It is preferred that the light sources are arranged at different heights in the cooking chamber and / or on different sides of the cooking chamber. The illumination device preferably comprises a plurality of separately controllable light sources. To produce different shadows, individual light sources are aimed at specific heights and / or at certain sides of the cooking chamber can be switched on and / or switched off. The evaluation device is particularly suitable and designed to control the light sources separately.

For example, in each case at least two and preferably four or five or more light sources are arranged on at least two opposite sides of the cooking chamber. It is also possible the arrangement of ten or more light sources on each side of the cooking chamber. The light sources are arranged in particular at different heights. It is possible that the light sources are designed as focused and / or point light sources, for example as a spot light. It is possible that the lighting device is also suitable and designed to illuminate the food to be targeted uniformly to avoid a shadow. Such illumination serves, in particular, to detect a shadow-free reference of the food to be cooked or the shelf level and / or the food support.

In one embodiment of the cooking appliance, it is provided that the lighting device at least temporarily provides the cooking chamber lighting for the visual inspection of the food to be cooked. This has the advantage that in addition to the lighting device can be dispensed with a further cooking chamber lighting. For this purpose, it is possible that the number and / or the intensity of the light sources for a lighting for visual inspection is adjusted accordingly.

The evaluation device is preferably suitable and designed to recognize an insertion position of at least one food support in the cooking chamber. The evaluation device is in particular suitable and designed to determine a shape and / or a height of the food by means of the shadow of the food to be cooked detected by the camera device. Preferably, the evaluation device is also suitable and designed to determine a two-dimensional extent of the food and, for example, its length and / or width and / or its diameter. In addition, the evaluation device is preferably suitable and designed to determine a volume of the food based on the height and the two-dimensional extent. In particular, the evaluation device is suitable and designed to provide the information of the control device. The control device is particularly suitable and designed to adjust the heating of the cooking chamber and / or other device functions based on the volume.

In all embodiments, it is preferred that the camera device comprises only one lens. In particular, the camera device and the objective are suitable and designed to capture only two-dimensional images of objects. Such camera devices and lenses are inexpensive in suitable and reliable embodiments and can also be implemented with little design effort in a cooking appliance.

Further advantages and features of the present invention will become apparent from the embodiments, which are explained below with reference to the accompanying figures.

In the figures show:

1 a purely schematic representation of a cooking appliance according to the invention with a cooking chamber in a front view;

2 a highly schematic cooking appliance with a lighting device in a set lighting situation;

3 a sectional view of the cooking appliance of 2 in a plan view;

4 the cooking appliance with a lighting device in a different lighting situation;

5 a sectional view of the cooking appliance of 4 in a plan view;

6 the cooking appliance in the same lighting situation with a larger food to be cooked;

7 a sectional view of the cooking appliance of 6 in a plan view;

8th the cooking appliance in the lighting situation with another food; and

9 a sectional view of the cooking appliance of 8th in a top view.

The 1 shows an inventive cooking appliance 1 which is here as an oven 100 is executed. The cooking appliance 1 can be operated by the method according to the invention. The cooking appliance 1 is intended here as a built-in device. It is also possible that the cooking appliance 1 is designed as a stove or stand unit. The cooking appliance 1 has a cooking space 2 which through a door 101 is closable. A viewing window 102 in the door 101 allows an insight into the oven 2 and serves for visual inspection during cooking.

For heating the cooking chamber 2 Various heating sources are available. Among other things, it is possible to heat with a circulating air heating source, with top and bottom heat, in hot air mode and / or with a grill function. It is also possible that the oven 100 as a combination device with one Microwave function and / or a Dampfgarfunktion is formed.

The cooking appliance 1 comprises a control device 4 for controlling or regulating device functions. By means of the control device 4 the heating power of a heating source is adjusted so that in the cooking chamber 2 Temperatures are present which are in the range of a required setpoint temperature. For monitoring the temperatures in the cooking chamber 2 a sensor device can be provided. About the controller 4 Furthermore, different operating modes and preferably different program operating modes and automatic functions can be executed.

The cooking appliance 1 is via an operating device 11 operable. For example, an operating mode, the operating temperature and / or a program operating mode or automatic function can thus be selected and set. The operating device 11 is here with a user interface 21 equipped to display the user various information and / or signals about the operation and the cooking process. This includes the user interface 21 for example, a display. In addition, the user can via the user interface 21 Make inputs, for example, to make individual settings. It can also be provided that via the user interface 21 Certain operating parameters of an automatic function can be adjusted individually, such as the cooking time. The user interface 21 For this purpose, it can have one or more keys and / or be designed as a touch-sensitive surface or touchscreen.

In the oven 2 there is a food here 3 which is on a food support 13 is positioned. The food support 13 is for example a baking sheet or a rust. The food support 13 is in the oven 2 taken on a Gargutträgeraufnahme not shown here. The food support receptacle offers several insertion positions 12 so that the user the food support 13 in different heights in the oven 2 can insert.

The cooking appliance 1 includes a camera device 5 , which are not visible here on an upper side of the cooking chamber 2 is arranged. The camera device 5 serves here for recording shots of the food 3 , The images are taken from an evaluation device 8th be used to determine one or more parameters that for the food 3 are characteristic. The so on the food 3 The information obtained is provided by the evaluation facility 8th the control device 4 provided so that they can take into account the cooking properties in cooking mode accordingly.

The cooking space 2 here is a lighting device 7 assigned, which two on opposite sides 22 of the cooking chamber 2 arranged lighting units 47 having. The lighting units 47 both each comprise several light sources, which are not visible here behind the door 101 are arranged. Through the lighting device 7 becomes the food 3 during detection by the camera device 5 purposefully illuminated.

In addition, the lighting device 7 here also as an oven lighting 37 serve, which during a cooking operation the cooking chamber 2 illuminates, allowing the user to cook through the viewing window 102 good at watching. Here is the lighting device 7 formed adjustable by the control device, so that the illumination of the cooking chamber 2 In cooking mode, a different lighting situation than for the detection of the food 3 with the camera device 5 is adjustable. It can be used to illuminate the cooking space 2 during the cooking operation but also its own, separate oven lighting 37 be provided.

To determine the characteristic parameter of the food 3 this is done with the lighting device 7 deliberately lit so that there is a shadow not visible here 6 raises. The shadow is cast with the camera 5 recorded and by the evaluation device 8th evaluated. Based on the dimensions of the shadow 6 can then, for example, the height of the food 3 be determined. In conjunction with the length and width of the food 3 can determine the volume of the food by means of the height 3 be calculated. In addition, other geometric properties of the food can 3 and, for example, its shape are determined. These characteristic parameters for the food can be used particularly well for controlling automatic programs, since, for example, the cooking time very much on the volume of the food 3 appends. So z. B. extended or shortened provided in an automatic function cooking time, depending on whether it is very large or rather small food 3 is.

In the 2 is a highly schematic cooking appliance 1 shown in the oven 2 a food support 13 with a food 3 is inserted. The lighting device 7 includes here on each page 22 of the cooking chamber 23 highly schematically illustrated light sources 17 , It is also conceivable that on each side 22 of the cooking chamber 2 also four or five or for example also ten or more light sources 17 are provided. These are the light sources 17 here vertically arranged with each other, so on each side 22 light sources 17 are positioned at different heights. The dashed dotted lines indicate the projection beams, which of the respective light sources 17 out. The solid lines indicate that through the respective light source 17 illuminated area.

The camera device 5 is arranged here on the cooking chamber ceiling and has a detection area 15 on, which is essentially the width or the bearing surface of the food support 13 equivalent.

In the lighting situation shown here are all light sources 17 the lighting device 7 switched on. This illumination situation is used in particular to record a shadow-free reference image. Moreover, this lighting situation can also be used as cooking chamber lighting during the cooking operation 37 be used. These are the light sources 17 aligned so that from the point of view of the camera device 5 the illumination is as homogeneous as possible. In such a homogeneous illumination is trying as little visible shadow in the image around the food 3 to create. The homogeneous illumination is thus a two-sided arrangement of the light sources 17 reached. In addition, the light sources 17 arranged one above the other.

In the 3 is the cooking appliance 1 in a sectional view from a top view from the perspective of the camera device 5 shown. The coverage area 15 the camera device 5 is shown hatched here and corresponds essentially to the extension of the food support 13 , The food 3 was not hatched for clarity, although it is also in the coverage area 15 lies.

The food 3 will be here with in the 2 described adjustment of the lighting device 7 illuminated, so that there is no shadow can be seen here. From an image taken in the lighting situation shown here is therefore no information about the height of the food 3 won. Due to the homogeneous illumination, however, an image recorded in this lighting situation can be used particularly well for an evaluation, in which an extent or a diameter of the food to be cooked 3 should be determined. Due to the homogeneous illumination, the food can be cooked 3 from the evaluation device 8th as part of an image analysis particularly good of the underlying food support 13 be differentiated.

That in the 2 and 3 cooking product shown is substantially similar to a flattened, spherical object. From the point of view of camera setup 5 This results in a substantially round, two-dimensional image. A very similar picture would be the camera setup 5 for example, even when the food to be cooked 3 would have the same diameter, but would be slightly higher. Therefore, a shot at a shadow-free, uniform lighting, as z. B. is provided in a conventional Garraumbeleuchtung, no useful information about the three-dimensional geometry of the food 3 ready.

The 4 shows a lighting situation in which the food to be cooked 3 targeted unevenly illuminated to produce high-contrast shadows. These were individual light sources 17 turned off, so the food to be cooked 3 a recognizable shadow 6 on the food support 13 throws. The dashed lines represent here straight lines, which between the food support 13 and the respective light source 17 run while the food 3 touch. These lines thus separate the illuminated area on the food support 13 from the area in which the food to be cooked 3 a shadow 6 on the food support 13 throws.

The 5 shows the cooking appliance 1 in the lighting situation of 4 from the perspective of the camera device 5 , Whose detection range 15 hatched again. For better clarity, the food was 3 although it is in the coverage area 15 lies, not shown here hatched again. Due to the lighting situation is about the food 3 around now a shadow 6 to recognize which is illustrated here by a hatched area.

To create these shadows 6 were the two upper, opposite light sources 17 turned on and the other light sources 17 switched off. The light sources 17 here are equipped with a directional radiation, so that there is a corresponding bundled light beam. At the same time the light sources became 17 Switched here so that the food 3 and the associated shadows 6 as good as possible and completely within the detection range 15 the camera device 5 can be displayed.

The 6 shows a cooking appliance 1 in which a food to be cooked 3 with the camera device 5 in the same lighting situation as in the 4 is detected. The food 3 Here, however, is slightly higher than that in the 4 recorded food 3 , Due to the higher food to be cooked 3 run the two outer, dashed projection beams of the edges of the food 3 further apart.

In the 7 is the cooking appliance 1 of the 6 from the perspective of the camera device 5 shown. Due to the higher food 3 This results in a wider, oval shadow around the illuminated food 3 ,

For a given lighting situation, there is thus a connection between one Length of the shadow 6 and the height of the food 3 , Therefore, based on the with the camera 5 captured images the width or diameter of each cast shadows 6 be measured. Based on the extent of the shadows 6 can the height of the food 3 be determined.

The 8th shows relevant dimensions for a calculation of height 23 a food 3 , The food 3 is formed by way of example cuboid.

The 9 shows the food 3 of the 8th in a cooking appliance 1 from the perspective of the camera device 5 ,

A prerequisite for the calculation of the height 23 and thus also the volume of the food 3 is that the food 3 and the surrounding shadow 6 from the evaluation device 8th can be clearly distinguished. The intensity of the light sources 17 is therefore adjusted so that there is sufficient contrast. In addition, light sources 17 used, which emit a correspondingly bundled light beam. The evaluation device 8th can also perform a corresponding image processing, by which the contrast range of the recorded images is increased or improved accordingly.

Another prerequisite is that the food 3 not over the complete coverage 15 extends. In addition, the thrown shadow must 6 in the coverage area 15 lie. This is preferably done by the evaluation 8th a check, whether the cast shadow 6 within the coverage 15 lie. For example, if the shadow cast over the detection area 15 Go beyond, a change in the lighting and / or the insertion position of the food support 13 be provided. 12 , Then, for example, a message to the user via the user interface 21 done so that this the food support 13 in another slot position 12 can position. An adaptation of the shadow with respect to the detection area 15 can also by turning on other light sources 17 respectively. For example, the shadow cast correspondingly shorter, if a higher-lying light source 17 is turned on.

The two-dimensional extent of the food 3 and thus its length and width or its diameter can be determined from the surface of the food 3 be determined in the recorded image. This requires the real extent of the captured image or the detection area 15 be known. As these, however, also from the removal of the food support 13 to the camera device 5 It depends on the insertion position 12 of the food support 13 in the oven 2 to know. This can be the insertion position 12 can be determined in different ways. For example, the user may use the user interface 21 are specified in which rack level he Gargutträger 13 has to push. Another possibility is the insertion position 12 by interrogating appropriate sensors. For example, corresponding switches can be provided on the food support holder, which can be provided by inserting a food support 13 be operated. Another possibility is, based on the captured image information, the insertion position 12 to investigate. If z. B. the extent of the detection area 15 is known, the insertion position can be determined based on the image area, which is taken by the food support. It is also possible to use focus settings of the camera device 5 for determining the insertion position 12 , It is also possible that the user through the user interface 21 makes an input, and thus the evaluation 8th tells in which slot position 12 he the food support 13 has inserted.

The determination of the real extent of the recorded image is particularly simple here, since the image in the example shown here, the entire rack level or the entire food support 13 detected. The dimensions of the rack level of the cooking appliance 1 firmly predetermined by the cooking chamber walls, so that these dimensions in the evaluation 8th can be deposited, for. B. factory. Also the dimensions of the food carrier 13 can be deposited. Now, knowing the real dimensions of the recorded image or the coverage area 15 the real dimensions of the food to be cooked are calculated in a manner known per se. For example, the number of pixels of the captured image is known, so that the object dimensions can be determined in millimeters per pixel. The width 33 of the food 3 as well as its length or diameter can thus be determined.

Following the same procedure preferably also the real dimensions of the shadows 6 certainly. Detecting the shadows 6 takes place due to the different contrast to the food 3 , Has the evaluation device 8th the shadow 6 recognized as such, this performs a determination of the real extent, as previously for the food 3 has been described. So the expansion can 16 or the diameter of the shadow 6 be determined.

The expansion 16 of the shadow 6 is proportional to the height 23 of the food 3 and to the width 33 of the food 3 , The bigger the height 23 of the food 3 , the bigger the expansion 16 of the shadow 6 , By determining the extent 16 of the shadow 6 and the width 33 of the food 3 can thus the height 23 of the food 3 be determined in a conventional manner. Also with food 3 , which are not like cuboid here, can be determined by the extent 16 of the shadow 6 and knowing the real extent of the food 3 also in a conventional manner, the height 23 of the food 3 be determined. Based on the calculated height 23 and the determined from the recording surface of the food 3 In addition, it is easy to adjust the volume of the food 3 getting closed.

A particularly reliable determination of height 23 of the food 3 may be aware of the distance 32 the respective light source 17 to the detection area 15 be derived. This distance 32 results from the height of the light source 17 above the shelf level 12 of the food support 13 , This is in the evaluation 18 preferably deposited, in which amount the respective light sources 17 in the oven 2 are located. In addition, the height of the insertion position 12 in the oven 2 also known and in the evaluation 8th deposited. This allows the distance 32 the respective light source 17 above the food support 13 or the detection area 15 be reliably determined. Based on the distance 32 and the extent 16 of the shadow 6 as well as the width 33 of the food 3 then can the height 23 of the food 3 be calculated accordingly.

The shadow cast can also be used to determine a geometric shape of the food 3 is used. For example, a curvature of the surface of the food 3 be determined. For this purpose, an image sequence is preferably generated, wherein for each image, an illumination with light sources 17 from a different height. As a result, the change of the shadow size over the individual images can cause the curvature of the surface of the food to be cooked 3 be determined. Taking into account the geometric shape of the food 3 can its height 23 be determined even more reliably from the shadow.

LIST OF REFERENCE NUMBERS

1

 Cooking appliance

2

 oven

3

 be cooked

4

 control device

5

 camera means

6

 shadow

7

 lighting device

8th

 evaluation

11

 operating device

12

 insertion position

13

 food support

15

 detection range

16

 shadow width

17

 light source

21

 User interface

22

 page

23

 height

25

 detection width

32

 distance

33

 width

37

 Oven light

47

 lighting unit

100

 oven

101

 door

102

 window

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• https://en.wikipedia.org/wiki/3D-camera [0006]

Claims (16)

Method for operating a cooking appliance ( 1 ) with at least one heatable cooking space ( 2 ) for the preparation of food ( 3 ), wherein the heating of the cooking chamber ( 2 ) by at least one control device ( 4 ) and the control device ( 4 ) at least one for the food ( 3 ) takes into account characteristic parameters and in which the product to be cooked ( 3 ) at least partially with at least one camera device ( 5 ) is detected, characterized in that the food ( 3 ) for generating at least one shadow ( 6 ) by means of at least one illumination device ( 7 ) is at least partially illuminated and that of the food ( 3 ) thrown shadows ( 6 ) through the camera device ( 5 ) and that on the basis of the detected shadow ( 6 ) by at least one evaluation device ( 8th ) for the food ( 3 ) characteristic parameters is determined. A method according to claim 1, characterized in that as a characteristic parameter, a volume and / or a shape and / or a kind of the food ( 3 ) is determined. Method according to one of the preceding claims, characterized in that the food ( 3 ) on a food support ( 13 ) positioned in the cooking chamber ( 2 ) and that an insertion position ( 12 ) of the food support ( 13 ) in the cooking chamber ( 2 ) is determined by at least one of the following steps: at least one sensory detection of the insertion position ( 12 ) is performed via a user interface ( 21 ) a required insertion position ( 12 ), it is transmitted via a user interface ( 21 ) the inserted position ( 12 ), it will be with the camera device ( 5 ) evaluated and for calculating the distance of the food support ( 13 ) to the camera device ( 5 ) and from this the insertion position ( 12 ). Method according to one of the preceding claims, characterized in that the food ( 3 ) with the illumination device ( 7 ) is illuminated uniformly targeted and that the food ( 3 ) with the camera device ( 5 ) is detected. Method according to one of the preceding claims, characterized in that the food ( 3 ) with the illumination device ( 7 ) of at least two sides ( 22 ) of the cooking chamber ( 2 ) and / or from at least two different heights of the cooking chamber ( 2 ) is illuminated unevenly and that thereby each of the food ( 3 ) thrown shadows ( 6 ) with the camera device ( 7 ) is detected. Method according to one of the preceding claims, characterized in that targeted individual light sources ( 17 ) of the lighting device ( 7 ) at different positions in the cooking chamber ( 2 ) are switched off and / or switched on and / or adjusted in intensity. Method according to one of the preceding claims, characterized in that with reference to the camera device ( 5 ) is checked, whether the shadows intended for evaluation ( 6 ) of the food ( 3 ) within a coverage area ( 15 ) of the camera device ( 5 ) lie. Method according to one of the preceding claims, characterized in that with reference to the camera device ( 5 ) information is checked, whether the detected shadows ( 6 ) of the food ( 3 ) have a contrast range necessary for the evaluation. Method according to one of the preceding claims, characterized in that by means of the evaluation device ( 8th ) an extension of the camera device ( 5 ) captured shadow ( 6 ) and from this a shape and / or a height ( 23 ) of the food ( 3 ) is calculated. Method according to the preceding claim, characterized in that by means of the evaluation device ( 8th ) a two-dimensional extent of the with the camera device ( 5 ) recorded food ( 3 ) and that from the two-dimensional extent and the height ( 23 ) of the food ( 3 ) the volume of the food ( 3 ) is determined. Method according to one of the preceding claims, characterized in that the detection of the shadow ( 6 ) with the camera device ( 5 ) and the determination of the characteristic parameter by the evaluation device ( 8th ) be performed at least once before the start of a cooking process and / or at least once during a cooking process and / or at least once after a cooking process. Cooking appliance ( 1 ), in particular for operating according to a method of the preceding claims, with at least one heatable cooking chamber ( 2 ) for the preparation of food ( 3 ), wherein the heating of the cooking chamber ( 2 ) by at least one control device ( 4 ) is adjustable and wherein the control device ( 4 ) is suitable and designed, while at least one for the food ( 3 ) and to determine at least one camera device ( 5 ), which is suitable and designed, the food ( 3 ) at least partially to capture, characterized in that the camera device ( 5 ) at least one illumination device ( 7 ) with at least two separately controllable light sources ( 17 ) and that the illumination device ( 7 ) is suitable and designed, the food ( 3 ) for generating at least one shadow ( 6 ) and that the camera device ( 5 ) is suitable and adapted to that of the food ( 3 ) thrown shadows ( 6 ) and at least one evaluation device ( 8th ) and that the evaluation device ( 8th ) is suitable and designed on the basis of the detected shadow ( 6 ) for the food ( 3 ) to determine characteristic parameters. Cooking appliance ( 1 ) according to the preceding claim, characterized in that the light sources ( 17 ) at different heights in the cooking chamber ( 2 ) and / or on different sides ( 22 ) of the cooking chamber ( 2 ) and that for generating different shadows ( 6 ) individual light sources ( 17 ) at certain heights and / or on certain sides ( 22 ) of the cooking chamber ( 2 ) can be selectively switched on and / or off. Cooking appliance ( 1 ) according to one of the two preceding claims, characterized in that the illumination device ( 7 ) at least temporarily the cooking chamber lighting ( 37 ) for visual inspection of the food ( 3 ). Cooking appliance ( 1 ) according to one of the three preceding claims, characterized in that the evaluation device ( 8th ) is suitable and designed to have an insertion position ( 12 ) at least one food support ( 13 ) in the cooking chamber ( 2 ) to recognize. Cooking appliance ( 1 ) according to one of the four preceding claims, characterized in that the evaluation device ( 8th ) is suitable and designed on the basis of the by the camera device ( 5 ) captured shadow ( 6 ) of the food ( 3 ) a shape and / or height of the food ( 3 ).

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