EP3152498B1 - Cooking device with light pattern projector and camera - Google Patents

Description

The invention relates to a cooking appliance, comprising a cooking chamber with a loading opening that can be closed by means of a door, a light pattern projector fixed in relation to the cooking chamber for generating a light pattern, a camera for taking pictures from an area that can be irradiated by the light pattern and one coupled to the camera Evaluation device for calculating a three-dimensional shape of at least one object which is located in the area that can be irradiated by the light pattern, by means of a light pattern evaluation. The invention is particularly advantageously applicable to ovens. The invention is particularly advantageously applicable to household appliances.

EP 2 530 387 A1 discloses an oven with a device for detecting a three-dimensional shape of food on a baking tray of the oven. The device contains at least one laser which is arranged or can be arranged over a cooking space of the oven. A laser beam from the laser is directed downwards. The device further comprises at least one camera which is arranged or can be arranged above a baking sheet of the oven. The camera is arranged or can be arranged in a front section of the furnace. The baking tray and the camera are mechanically coupled so that the camera and the baking tray can be moved synchronously. An upper side of the baking sheet is in a field of view of the camera. An angle between a central axis of a field of view of the camera and the laser beam is predetermined. The device for detecting the three-dimensional shape of the food on the baking sheet is also disclosed.

EP 2 149 755 A1 discloses an oven for heating food products comprising a cooking chamber to receive the product via a loading port and a product feature corn extraction system configured to extract at least one product feature representative of a configuration of the product, the system comprising : at least one camera, which is designed and arranged to record top views of the product, and at least one contour plane unit that is used to extract or highlight contour planes at least a portion of the product and, as the case may be, an object that to introduce together is provided with the product in the cooking space, and a product feature extraction unit for extracting the at least one product feature on the basis of the top view of the product and contour planes of the product.

A method is used for operating an oven for heating a food product, comprising the steps: a) extracting a product feature of a product that is to be heated in a chamber of the oven by recording at least one top view of a product using at least one camera, extracting and / or Highlighting of contour planes of at least one section of the product and, as may be the case, an object that is intended to be introduced together with the product into the cooking chamber, using at least one contour plane unit, and b) extracting the at least a product feature based on the plan views and contour planes, based on at least one product feature, and optionally secondary data representing a physical configuration of the product, preferably at least one of the product temperature, a product weight and a product density, for automatic control or for Heating the Product.

EP 1 921 384 A1 discloses a device for determining the temperature inside a product to be cooked. The device has at least one temperature sensor for detecting at least one surface temperature of the item to be cooked and / or an ambient temperature of the item to be cooked, in particular at a measuring location within a cooking space surrounding the item to be cooked, preferably with an ambient temperature sensor arranged at the measuring location. Furthermore, the device comprises at least one distance sensor for detecting one or a plurality of distances between the distance sensor on the one hand and one or a plurality of distance measuring points on the surface of the food to be cooked on the other hand. In addition, the device comprises at least one time measuring device for recording the time during preparation of the food and at least one calculation device for calculating the temperature inside the food from the surface temperature of the food and / or ambient temperature, the interval or the plurality of intervals, the time and one Starting temperature of the food. A method for determining the temperature inside a product to be cooked is also disclosed.

DE 197 48 062 A1 discloses a method and a device for three-dimensional, optical measurement of objects. Afterwards, the measuring system must be calibrated in the case of optical, areally working, three-dimensional measuring methods, since the geometric parameters of the system must be known in order to carry out the triangulation calculation. After calibration, the lenses must no longer be adjusted, as this changes the imaging errors of the optics in an uncontrollable manner. The method enables the measuring system to be set to a different measuring field size even after calibration. By determining the inner bundle of rays from the projector and camera by means of a device which simultaneously serves to focus on a wide variety of measuring distances, the measuring system is adapted to different measuring field sizes in such a way that the geometric changes made to the system can be precisely determined and those that are decisive for the triangulation Parameters can be calculated without recalibration. The calibration now takes place with a measurement field size which is selected solely from the point of view of the ease of manufacture of the calibration device and easily manageable dimensions. Once the system has been calibrated, it can then be set to the most varied, in particular very large, measurement distances and measurement volumes. An application to household appliances or cooking appliances is not disclosed.

WO 00/70303 discloses a method and an apparatus for the imaging of three-dimensional objects, comprising a structural light source which projects a focused image onto an object by passing light either continuously or in a stroboscopic manner through an optical grating and a downstream projection lens. An application to household appliances or cooking appliances is not disclosed.

DE 10 2006 005 874 A1 discloses a device and a method for contactless measurement of, in particular, cylindrical objects on surfaces. To this end, it is proposed to use a laser to generate a line on the surface, the reflection of which is measured by a camera. After the line has been recorded, it is shifted parallel to itself several times and the recording is repeated. In this way, a shadow image of the object arranged on the surface is generated by successively displacing the line. It is also possible to separate the multiline triangulation and the shadow formation from one another. A stationary laser or another radiation source can be used for multiline triangulation. The Shadow formation can be carried out by two also stationary radiation sources, for example a row of LEDs, simultaneously or one after the other. The use of a stationary structure of radiation sources and camera simplifies and makes the mechanical structure cheaper. An application to household appliances or cooking appliances is not disclosed.

WO 2010/102261 A1 discloses a food treatment device in which food located in the device is treated by radiation. The food treatment device has a camera for image recognition. A type of food (eg pizza) is preset, and the image recognition can identify its location, occupancy, etc., for example. A light pattern can also be used to identify the height or other expansion of the pizza.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art and specifically to provide a particularly versatile possibility for measuring food to be cooked.

This object is achieved according to the features of the independent claim. Preferred embodiments can be inferred in particular from the dependent claims.

The object is achieved by a cooking device having a cooking chamber with a loading opening that can be closed by means of a door, (at least) one projector (referred to below as a "light pattern projector" without restricting generality) for generating a light pattern, at least) one camera for recording images from an area that can be irradiated by the light pattern and an evaluation device coupled to the camera for calculating a three-dimensional shape of at least one object that is located in the area that can be irradiated by the light pattern by means of a light pattern evaluation, the The light pattern projector is arranged to radiate a light pattern into the cooking chamber, the camera is arranged in particular fixedly with respect to the cooking chamber, the camera is arranged for taking pictures from an area of the cooking chamber that can be irradiated by the light pattern, even when the cooking chamber is closed and the Evaluation device is set up for repeated calculation of the three-dimensional shape of the at least one object, which is located in the region of the cooking chamber that can be irradiated by the light pattern, during operation of the cooking appliance. The cooking appliance has the advantage that the depth information can be used as a parameter for automatic programs. A possible change in volume of the item to be cooked during the cooking process when the cooking appliance is in operation can thus be recorded and a type of item to be cooked can be determined. In this way, the control of the cooking parameters can be influenced, for example the cooking space temperature. So For example, a rising behavior of a bread and a shrinking behavior of a piece of meat may be recorded and possibly used to control the cooking appliance.

For the generation of the three-dimensional shape or the three-dimensional image of the region of the cooking chamber that can be irradiated by the light pattern, the basically known method of patterned or structured light (“structure light”) is used in particular. A defined light pattern is projected onto the object to be recorded or measured by means of the light pattern projector and recorded by the camera. Based on the degree of deformation of the light pattern on the object, a three-dimensional model of this object can be calculated by means of the evaluation device. A depth resolution of a specific image point depends on the angle between a light beam for generating this image point and a normal vector to a plane or to an optical axis of the camera. A theoretical optimum resolution would be at the largest possible angle. However, with increasing approach to this optimum, the visibility of the projected light pattern on the object surface and thus its detectability by the camera deteriorate. A position determination is only possible for those points which on the one hand are visible from the camera and on the other hand can be illuminated by the light pattern projector (ie not in a shadow).

The cooking appliance may be or have an oven, in particular an oven. The cooking space may then also be referred to as the oven space. The oven may be a stand-alone oven or it may be part of an oven / hob combination or range. In addition or as an alternative to being configured as an oven, the oven may have a microwave and / or steam treatment functionality.

It is a further development that the cooking appliance is a household appliance, in particular in the sense of “white goods”.

The light pattern projector, together with the camera and the evaluation device, may also be referred to as a so-called “3D scanner”. The light pattern projector emits at least one light pattern, for example a stripe and / or point pattern, but is not limited thereto. In this way, any other light pattern can be generated, for example ring-shaped Pattern, wave pattern, etc. A pattern is selected in particular in such a way that it matches the desired resolution of the three-dimensional image.

In particular, the camera may be a digital camera. It may take individual pictures and / or picture sequences, especially videos.

The evaluation device may be an independent device of the cooking appliance, e.g. in the form of electronics, in particular on a separate circuit board. Alternatively, it may be integrated into a further device of the cooking appliance, e.g. into a central control device. This further device may then also be able to carry out the evaluation in particular.

It is an embodiment that an optical axis of the light pattern projector and an optical axis of the camera are at an angle between 20 ° and 30 ° to one another. This achieves good visibility of the projected light pattern with good depth resolution and consequently a particularly reliable determination of the three-dimensional shape of the at least one object.

Another embodiment is that the light pattern projector and the camera are arranged behind a wall or muffle of the cooking chamber, in particular at a predefined distance. In this way, these two components can be sufficiently thermally insulated from the cooking space. The cooking chamber wall may have a respective window for the light pattern projector and for the camera. The windows may be covered with transparent glass.

It is a further embodiment that the light pattern projector and the camera are arranged behind a ceiling of the cooking space. In this way, a food support (eg a baking sheet or a wire rack) can be fully illuminated and detected particularly easily. This in turn enables particularly precise images and measurements to be generated. This position has the further advantage that cooling air conducted over the ceiling (eg for cooling electronics arranged above the cooking chamber) can also be used to cool the light pattern projector and the camera. The distance between the light pattern projector and the camera behind the cooking chamber wall or muffle can be muffle-specific.

It is yet another embodiment that different light patterns can be radiated into the cooking space by means of the light pattern projector. As a result, the three-dimensional shape of the at least one object can be determined with a particularly small error. For example, alternating point-like and strip-like light patterns can be irradiated and evaluated. Different dot patterns and / or different stripe patterns can also be radiated into the cooking space. This can take place in a predetermined sequence or if a measured depth resolution does not produce sufficient results.

It is also an embodiment that the light pattern projector has at least one pixel-like screen or screen for shaping the light pattern. This enables a particularly simple design and variation of the light pattern with high resolution. The pixel-like screen may e.g. be a liquid crystal screen or an LCD screen. The pixel-like screen may itself generate light as a structural unit in order to adequately illuminate the cooking space with the light pattern. However, the pixel-like screen may e.g. can also be backlit by at least one separate light source so that it can be used as a 'variable diaphragm'. The latter case enables particularly high luminous fluxes.

The light emitted by the light pattern projector and received by the camera may be visible light and / or infrared light. The advantage of infrared light is that an observer looking into the cooking space cannot see the light pattern.

It is a further development that the 3D scanner can be calibrated. In one embodiment, there is at least one calibration mark in the muffle. Based on the known position of the at least one calibration marking relative to the at least one object to be measured, a distance of the object and thus also its size or shape can be determined more precisely.

It is an alternative or additional embodiment that at least one calibration marking is located on a food support, for example on a baking sheet or a grate etc. In particular, it may be located on a surface for use or storage of the food support for food. This calibration mark especially likes have a known size, so that a distance to the camera can be determined by means of the size recorded by the camera.

A calibration marking may be, for example, a colored marking and / or a predetermined shaped marking. The calibration marks can also be defined geometrical features, e.g. Functional areas of the cooking chamber wall or muffle such as insertion protrusions. The calibration mark (s) can also serve to determine the insertion level on which the object to be measured is located.

The calibration preferably takes place in the closed muffle or with the cooking space closed, in particular at the start of a cooking process. This minimizes any influence on the measurement from the environment. In order to simplify reliable detection of the item to be cooked and the previous calibration, it is advantageous to predefine preferred insertion levels in the cooking space for the 3D measurement (“3D scan”). They are preferably located in a lower third of the muffle. This has the advantage that large-area and / or large-volume objects can also be reliably identified and measured.

The 3D measurement of the object advantageously takes place after the calibration. In principle, however, calibration can also be dispensed with.

It is a further development that the cooking appliance is equipped with an insertion identifier. The cooking appliance may then, when it detects that a food carrier is located on an insertion level that is unfavorable for a 3D measurement, to output a warning signal and / or a display to a user. The cooking appliance may then also prevent a 3D scan.

According to the invention, the evaluation device is set up to recognize a type of item to be cooked on the basis of its shape and shape change calculated by the light pattern evaluation. This enables, among other things, an automatic adaptation of cooking parameters to the food (e.g. within the framework of a cooking program) and / or an adaptation of user guidance to the food (e.g. by displaying cooking parameters and / or cooking programs suitable for the recognized food).

The cooking appliance is set up to recognize the food being cooked on the basis of an image evaluation of images recorded by the camera (without 3D measurement, also referred to as “image recognition” below) and the 3D scan. Recognition of the food to be cooked on the basis of a combined image recognition and a 3D measurement enables a higher recognition probability through the additional height and depth information. This may e.g. enter as information in an image recognition algorithm.

It is also an embodiment that the evaluation device is set up to recognize a type of food carrier, e.g. whether the food is on a wire rack or on a baking sheet. This information can be used by the cooking appliance, for example, to set or adapt cooking parameters, for example a heating output of upper and / or lower heating or an activation and / or setting of a heating output of a circulating air heater.

It is a further development that the evaluation device is set up to recognize a type of accessory, in particular cooking utensils, for example a roasting pan or the like placed on a food support, in which the food is located. So it may be measurable whether the food to be cooked is in an open roaster or the roaster is closed. This information may also be used by the cooking appliance to set or adapt cooking parameters, possibly including the option of selecting the cooking method used. If the roaster is closed, the cooking device may be dependent on input from the user about the type of content.

It is also an embodiment that the evaluation device is set up to detect a core temperature of an object. The core temperature can be calculated using a correlation with a change in volume determined by the 3D scan during a cooking process with knowledge of the type of food being cooked. There is no need for a separate core temperature probe or roast skewer. For a particularly high level of reliability in determining the core temperature, it is a preferred development that the food to be cooked has an almost homogeneous structure. In this case, the core temperature is determined by means of a 3D scan, not as in EP 1 921 384 A1 described by means of one or more distance sensors.

According to the invention, the evaluation device is coupled to a control device of the cooking device and the control device is set up to adapt an operation of the cooking device on the basis of at least one object parameter determined by the evaluation device. As already mentioned in part above, the associated object can be food, an accessory and / or a food carrier. Object parameters can e.g. be a position, shape, volume or type, etc., of the object. In principle, the 3D information determined by one or more 3D scans can be used in particular for the automation of cooking, cooking and baking processes. As already mentioned, it is possible to carry out the 3D scan during a cooking process. The 3D information or 3D data that is then determined is not only used to identify the food being cooked, but also to adapt the cooking parameters if necessary. A cooking process or cooking process can thus be individually tailored to the food being cooked. If an exact detection of the food to be cooked is not possible, inputs from a user can in particular be taken into account. For this purpose, the cooking appliance may request the user to enter further information about the food to be cooked into the cooking appliance.

In yet another embodiment, the cooking appliance has a screen on which at least one three-dimensional image of at least one object recorded by the camera can be displayed. In other words, a three-dimensional representation of the contents of the cooking space is offered on a screen. This enables a particularly informative presentation of information for a user. The screen may e.g. be present on a front side or a top side of the cooking appliance. The screen may be a touch-sensitive sensor screen or touch screen.

One way of operating the cooking device is to carry out a calibration before starting a food treatment (e.g. a cooking process). Furthermore, shortly before the start of a food treatment, a 3D measurement or a 3D scan of the food to be cooked may be carried out in order to record its initial geometry. An object detection with regard to a type of item to be cooked, a type of an accessory and / or a type of a food carrier may also be carried out before the start of a food treatment.

In order to be able to determine a change in the shape of the item to be cooked or the food, at least one 3D scan may also take place during the food treatment, in particular several 3D scans at, for example, periodic intervals. According to the invention, by means of the recognized change in shape of the item to be cooked, a product to be cooked is identified and, for example, the end of treatment and / or a core temperature can be identified.

Another embodiment is that the light pattern projector is also provided for illuminating the cooking space. For example, it may illuminate the cooking space for viewing by a user and only shine the light pattern into the cooking space for comparatively short periods in between. This means that there is no need for a separate light source for lighting the cooking space.

Fig.1

zeigt eine Skizze einer Anordnung eines 3D-Scanners;

Fig.2

zeigt eine Skizze einer Rekonstruktion einer Form eines mittels eines 3D-Scanners vermessenen Objekts;

Fig.3

zeigt als Schnittdarstellung in Seitenansicht ein mit einem 3D-Scanner ausgerüstetes erfindungsgemäßes Gargerät; und

Fig.4

zeigt ein Diagramm eines Verlaufs einer Temperatur und eines Volumens eines geheizten Objekts mit einer Gargutbestimmung mittels eines erfindungsgemäßen Gargeräts.

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

Fig.1

shows a sketch of an arrangement of a 3D scanner;

Fig. 2

shows a sketch of a reconstruction of a shape of an object measured by means of a 3D scanner;

Fig. 3

shows, as a sectional illustration in side view, a cooking appliance according to the invention equipped with a 3D scanner; and

Fig. 4

shows a diagram of a course of a temperature and a volume of a heated object with a cooking product determination by means of a cooking device according to the invention.

Fig.1 shows an arrangement (“3D scanner”) for determining a three-dimensional shape of at least one object O (“3D scanner”), having a light pattern projector 1 directed at the object, a camera 2 directed at the object O, and a control device C for operation the light pattern projector 1 and for calculating a three-dimensional shape of the object O on the basis of at least one image received by the camera 2 by means of a light pattern evaluation. A screen 3 for viewing the object O ′ calculated by the control device C is optionally available.

The light pattern projector 1 generates a predetermined light pattern L, e.g. a stripe or dot pattern. The light pattern projector 1 emits its light in a light beam with a first optical axis A1.

The camera 2, typically a digital camera, has a field of view F with a second optical axis A2, which is oriented at an angle to the first optical axis A1 of the light pattern projector 1. In other words, the camera 2 is oriented at an angle to the light pattern projector 1. It observes a region of the object O that is or can be irradiated by the light pattern L.

Fig. 2 shows a sketch of a reconstruction of a shape of the object O measured by means of the 3D scanner 1, 2, C.

The light pattern projector 1 here has a light source Q, e.g. an array of light-emitting diodes, which is followed by a pattern-generating element in the form of a freely programmable LCD surface D that can be radiated through. Depending on the pattern M generated on the LCD surface D, a corresponding, in particular complementary, light pattern L is emitted from the LCD surface D. Alternatively, an LED screen may already serve as the light source (not shown), in which case a separate light source can then be dispensed with because of the background lighting ("backlighting") integrated therein.

In Fig. 2 is shown by way of example how light in the form of a vertical column or line G is radiated from the light pattern projector 1 onto the object O. A projection P (G) of this line G, which is distorted by the surface contour of the object O, appears on the object O. The camera 2 takes an image of this projection P (G), which reproduces the distortion, due to its inclination with respect to the light pattern projector 1. The camera 2 stores the projection P (G) as appropriately positioned image points B or "pixels" of a matrix that results from a matrix-like structure of individual sensors of a sensor array S of the camera, for example a CCD sensor array. The height or depth information is given by the deviation of the image points B from a vertical line.

If the planes of all vertical columns or lines G are known and a light beam r can be specified in space for each pixel B in the camera image from which the light incident on the respective individual sensor comes, and if there is also an assignment of the image points to the projection P (G) visible from the image points and thus also to the corresponding lines G, points on the object surface can be identified by a simple ray Reconstruct plane section.

The depth resolution depends on an angle W between the light beam r leading to the image point B and the direction of the column or line G. A theoretical optimum in terms of resolution would be at the largest possible angle W. However, the visibility of the projection P (G) on the surface of the object O and thus its detectability in the camera image deteriorate with increasing approach to this optimum. Since a reconstruction is only possible for those points on the surface of the object O which on the one hand are visible from the camera 2 and on the other hand can be illuminated by the light pattern projector 1, a compromise is made here. Such a 3D measurement or 3D scan is known in principle and is therefore not discussed further below.

Fig. 3 shows a sectional view in side view of a cooking device equipped with a 3D scanner in the form of an oven 4. The oven 4 has a cooking space 6 delimited by an oven muffle 5. The oven muffle 5 has at the front a loading opening 8 which can be closed by means of an oven door 7 and through which objects, in particular in the form of food O1, can be brought into the cooking space 6. A cooking space temperature T can be set by means of one or more, in particular electrically operated, heating elements (not shown).

On a ceiling 9 of the furnace muffle 5 there are two viewing windows 10 and 11, which can be covered, for example, with transparent glass panes. On the side of the furnace muffle 5 facing away from the cooking chamber 6 and at a predetermined distance from the furnace muffle 5, there is a light pattern projector 1 (e.g. with an LCD display for pattern generation) behind the viewing window 10 and a camera 2 behind the viewing window 11 their distance from the furnace muffle 5 is thermally protected. In addition, a flow of cooling air may sweep over the ceiling 9, for example for cooling components arranged there, such as a control device. The light pattern projector 1 and the camera 2 can also be further cooled by this cooling air flow.

The light pattern projector 1 and the camera 2 are arranged laterally offset from one another. In addition, their optical axes A1 and A2 assume an angle α between 20 ° and 30 °, which enables high depth resolution with good visibility. The light pattern projector 1 and the camera 2 are fixedly arranged in relation to the cooking space 6 and therefore do not move with it, for example when the oven door 7 is actuated.

The light pattern projector 1 emits a light pattern L through the viewing window 10 into the cooking space 6, in such a way that, from a predetermined distance from the ceiling 9, practically the entire horizontal surface of the cooking space 6 can be illuminated with the light pattern L. This may e.g. be the case in a lower half or in a lower third of the cooking space 6. The camera 2 records images from an area of the cooking chamber 6 that can at least partially be irradiated by the light pattern

The oven 4 also has an evaluation device 12 coupled to the camera 2 for calculating a three-dimensional shape, for example of the food O1 and a food carrier O2, which are located in the area that can be irradiated by the light pattern L, by means of a light pattern evaluation. This is based on a 3D measurement based on at least one image recorded by the camera 2. The light pattern projector 1, the camera 2 and the evaluation device 12 together form the 3D scanner. As shown here, the evaluation device 12 may be functionally integrated into a central control device of the baking oven 4 or it may be coupled to a control device as an independent unit.

A 3D scan comprising e.g. a recording of an image of the projection P (G) of the light pattern L by means of the camera 2 and a calculation of the three-dimensional shape of the food O1 and the food support O2 can be carried out with the oven door 7 or loading opening 8 closed.

In particular, when the oven door 7 is closed, but the cooking process has not yet started, a calibration can first be carried out. For this purpose, the food carrier O2 has one or more, for example colored, calibration markings K on its upper side, which have a known size and can be easily identified. For example, the size of the calibration mark (s) K recorded by the camera 2 allows a distance from the ceiling 9 and thus, for example, the insertion level used identify. In the case of an insertion level that is unsuitable for 3D measurement, for example because the rack level is too high, the oven 4 may output a message to a user, e.g. a display on a front screen 3 of a control panel 13. At least one calibration mark may also be located on the oven muffle 4.

After calibration, but before a cooking process or before treatment of the item to be cooked O1, an initial 3D measurement of the item to be cooked O1 may be carried out by means of the 3D scanner 1, 2, 12 in order to calculate its original shape. The calculated shape may be displayed on the screen 3. The calculated shape is used to determine the item to be cooked O1 by the cooking appliance 4, specifically for image recognition of the item to be cooked O1, which can also be carried out by the camera 2. A type of food carrier O2 may also be recognized by means of the 3D scanner 1, 2, 12. One or more cooking parameters of the cooking process may be adapted on the basis of a recognition of the food O1 and possibly the carrier O2. A cooking time and / or the cooking space temperature T may thus be adapted on the basis of the recognized type and / or the recognized volume of the item to be cooked and / or the recognized item carrier O2.

During the cooking process, 3D measurements can be carried out repeatedly in order to determine a change in shape and / or volume of the item to be cooked O1. In the event of a change in shape and / or volume, the oven 4 may adapt the cooking sequence, e.g. change the cooking time and / or the cooking space temperature, including switching off the heaters.

In order to improve the accuracy of the depth information and thus the volume of the item to be cooked O1, the light pattern projector 1 may project different light patterns L into the cooking space 6.

Fig. 4 shows a diagram of a profile of a temperature T and a volume V of the item to be cooked O1 with a determination of the item to be cooked by means of the cooking appliance 4, for example.

The food O1 to be cooked is purely by way of example a dough product, for example a round tarte flambée or a biscuit in a springform pan. A distinction between these two types of food O1 cannot be distinguished only by means of image recognition by the camera 2 because in a two-dimensional view from above (top view) both the tarte flambée and the sponge cake look circular. In addition, both are similar in color. However, both types of food require a different specific baking environment. If the tarte flambée is treated like the sponge cake, the result is unsatisfactory, which also applies to the reverse case. Through the 3D measurement by means of the 3D scanner 1, 2, 12, the cooking appliance 4 also receives spatial information about the food to be cooked O1. This spatial information of the initial state of the item to be cooked O1 before the cooking process (for example an initial volume V0) may already be sufficient to distinguish the flat tarte flambée from the higher biscuit. In addition, the type of item to be cooked O1 is determined by means of the 3D scanner 1, 2 12 from the change in its shape, in particular a change ΔV in its volume V.

Thus, the cooking space temperature T has an initial value Ts at an initial point in time ts of the cooking process, e.g. Room temperature. As the time t increases, the cooking space temperature T increases due to at least one activated heater, specifically for tarte flambée and sponge cake, as shown by the curve T1 + T2. If the cooking space temperature T reaches a target temperature Td1 for biscuits at a point in time td, which is below a target temperature Td2 for tarte flambée, a further 3D measurement is carried out in order to determine the type of item O1 to be cooked.

If the height or the volume V0 of the item to be cooked O1 has not changed significantly, it can be assumed that it is a tarte flambée which typically does not rise. Its volume curve is shown as curve V2. If the tarte flambée is recognized, the cooking appliance 4 can then, for example, increase its cooking space temperature T to the associated setpoint Td2, as indicated by the temperature curve T2. The cooking process ends at an associated end time te2.

However, if the height or the volume V0 of the item to be cooked O1 has increased noticeably by the ΔV at the time td, it can be assumed that it is a biscuit which typically rises. Its volume curve is shown as curve V1. If biscuit is recognized, the cooking appliance 4 may subsequently keep its cooking space temperature T at the associated setpoint Td1, as indicated by the temperature curve T1. The cooking process ends at an associated end time te1.

Using the height and / or volume information from the 3D measurement, a clear distinguishing feature for identifying the food to be cooked can therefore be provided.

List of reference symbols

1

Light pattern projector

2

camera

3

screen

4th

oven

5

Furnace muffle

6th

Cooking space

7th

Oven door

8th

Loading opening

9

blanket

10

Viewing window

11

Viewing window

12

Evaluation device

13

Control panel

A1

first optical axis

A2

second optical axis

B.

Pixel

C.

Control device

D.

LCD surface

F.

Field of view

G

line

K

Calibration marks

L.

Light pattern

M.

template

O

object

O1

Food

O2

Food carrier

O'

calculated object

P (G)

projection

Q

Light source

r

Beam of light

S.

Sensor array

T

Oven temperature

T1

Temperature curve

T2

Temperature curve

Rd1

Target temperature

t

Duration

td

Time when the target temperature Td1 is reached

te1

End time

te2

End time

ts

Start time of the cooking process

Ts

Cooking space temperature at the start time ts of the cooking process

V

volume

V0

Initial volume

V1

Volume history

V2

Volume history

ΔV

Volume change

W.

angle

α

angle

Claims (12)

1. Cooking appliance (4) having

   - a cooking chamber (6) with a loading opening (8) which can be closed by means of a door (7),

   - a light pattern projector (1) which is arranged in a fixed manner relative to the cooking chamber (6) for generating a light pattern (L),

   - a camera (2) for capturing images from a region which can be irradiated by the light pattern and

   - an analysis facility (12) which is coupled to the camera (2) for calculating a three-dimensional shape of an object (O; 01, O2), which is located in the region that can be irradiated by the light pattern (L), by means of a light pattern analysis,
   wherein

   - the light pattern projector (1) is arranged to radiate a light pattern (L) into the cooking chamber (6),

   - the camera (2) is arranged in a fixed manner relative to the cooking chamber (6),

   - the camera (2) is arranged to capture images from a region of the cooking chamber (6) which can be irradiated by the light pattern (L) even when the cooking chamber (6) is closed and

   - the analysis facility (12) designed to calculate repeatedly the three-dimensional shape of the at least one object (O; 01, O2), which is located in the region of the cooking chamber (6) which can be irradiated by the light pattern (L), during operation of the cooking appliance (4),
   characterised in that

   - the analysis facility (12) is designed to recognise a type of food (01) on the basis of its shape calculated by the light pattern analysis and change in shape during the operation of the cooking appliance (4), wherein

   - the analysis facility (12) is coupled to a control facility of the cooking appliance (4) and the control facility is designed to adjust operation of the cooking appliance (4) based on at least one object parameter determined by the analysis facility (12).
2. Cooking appliance (4) according to claim 1, characterised in that an optical axis (A1) of the light pattern projector (1) and an optical axis (A2) of the camera (2) are at an angle of between 20° and 30° to one another.
3. Cooking appliance (4) according to one of the preceding claims, characterised in that the light pattern projector (1) and camera (2) are arranged behind a ceiling (9) of the cooking chamber (6).
4. Cooking appliance (4) according to one of the preceding claims, characterised in that the light pattern projector (1) can radiate different light patterns (L) into the cooking chamber (6).
5. Cooking appliance (4) according to one of the preceding claims, characterised in that the light pattern projector (1) has at least one image point-type screen for shaping the light pattern (L).
6. Cooking appliance (4) according to one of the preceding claims, characterised in that predefined calibration markings (K) are present on a muffle (5) which delimits the cooking chamber.
7. Cooking appliance (4) according to one of the preceding claims, characterised in that the analysis facility (12) is designed to additionally recognise the type of food (01) on the basis of an image recognition.
8. Cooking appliance (4) according to one of the preceding claims, characterised in that the analysis facility (12) is designed to recognise a type of food support (O2) on the basis of its shape calculated by the light pattern analysis.
9. Cooking appliance (4) according to one of the preceding claims, characterised in that the analysis facility (12) is designed to recognise a type of accessory on the basis of its shape calculated by the light pattern analysis.
10. Cooking appliance (4) according to one of the preceding claims, characterised in that the analysis facility (12) is designed to recognise a core temperature of an object (01) on the basis of a change in its shape recognised by the light pattern analysis.
11. Cooking appliance (4) according to one of the preceding claims, characterised in that the cooking appliance (4) has a screen (3), on which a calculated shape of the food (01) can be displayed.
12. Cooking appliance (4) according to one of the preceding claims, characterised in that the light pattern projector (1) is also provided to illuminate the cooking chamber (6).

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