HK1153260A - Oven and method of operating the same - Google Patents

Description

Furnace and method for operating a furnace

Technical Field

The present invention relates to a furnace and a method of operating the same.

Background

The state of the art of operation of current ovens generally requires the user to select a temperature and duration, and to varying degrees to continuously observe the time course of the baking process.

To facilitate the operation of the oven, methods have been developed to automate the baking process to varying degrees. For example, these methods provide automatic temperature control based on surface or core temperature values measured by a temperature sensor during the baking process. For example, other known methods numerically approximate the actual temperature during the baking process based on the applied temperature and thermodynamic equations.

In the field of ovens and more particularly in the field of microwave ovens, it is generally known to use ultrasonic or infrared distance sensors or optical sensors to determine the position, shape or state of a product (for example freezing, refrigerating or thawing). The position, shape or condition is used to control the process of heating the article.

Other methods use cameras that photograph the article or are used to approximate the shape, volume or size of the article to improve the automation of the heating process.

The known methods and the furnaces involved are far from the possibility of providing fully automatic heating and often require the involvement of a user. In the field of furnace technology, it is therefore desirable to provide enhanced and user-friendly possibilities for the automatic operation of furnaces.

Disclosure of Invention

It is therefore an object of the present invention to provide a furnace which is adapted to perform the heating process more accurately in an automated manner. It is a further object to provide a method for more accurately operating a furnace in an automated manner.

Said object is achieved by a furnace and a method of operating a furnace according to claims 1 and 8, respectively. Advantageous embodiments are given in the dependent claims 2-7 and in the dependent claims 9-14.

According to a first aspect of the present invention, there is provided an oven for heating a food product, comprising a cavity adapted to receive the product via a cavity opening. The oven may be of any type suitable for heating products, in particular food products. Heating of the product may include baking, grilling, roasting, grilling, thawing, or the like. The oven is preferably an oven, but the oven may be of any other type, such as a microwave oven.

The oven according to the invention comprises an article feature acquisition system designed for acquiring at least one article feature representative of the article configuration. Possible article features are, without exhaustive limitation to the claims: vertical cross-section, horizontal cross-section, shape, in particular three-dimensional model, surface area, volume, size, in particular width, length, height, centre of gravity of the article, and centre of gravity to surface distance of the article.

The article feature acquisition system includes at least one camera designed and positioned to record a top view of the article. Top view of the article shall refer to any view of the article, such as a two-dimensional picture of the article showing at least a portion of the upper side of the article. Here, the upper side of the product shall mean the side of the product facing upwards at the position the product occupies during the heating process in the cavity.

The term "top view of the article" should not exclude that a part or part of the object fed into the cavity together with the article is part of the view. Such an object may be, for example, a tray carrying the article. Other objects are also conceivable, such as temperature sensors connected to or incorporated in the article. To facilitate distinguishing between the article and the object within view, for example, special indicia, colors, or color barcodes may be provided to the object.

The article feature acquisition system further comprises at least one contour line device designed and positioned to acquire or illuminate at least a portion of the article and, as the case may be, the contour line of an object to be placed into the cavity along with the food article.

Further, the article feature acquisition system includes an article feature acquisition device for acquiring the at least one article feature based on the article top view and the contour line.

It should be mentioned that the invention is not limited to a single article and a single object. The invention is of course also applicable to more than one article and more than one object, respectively.

Providing and using top view and contour lines of the article makes it possible to obtain article features or more precisely article features. More precise article characteristics (e.g., shape, volume, etc.) are the basis for more precise automated heating processes. In particular, the automatic heating process may be performed with minimal or no user involvement.

The mounting position of at least one of the at least one camera and the at least one profile line device is preferably as follows: i.e. high quality accurate views and contours can be obtained for a wide range of article types, article shapes and article positions within the cavity. Preferred mounting positions are: the upper part of the opening is preferably located at the entrance position, above the door closing and opening the opening, and the upper part of the chamber is preferably half the depth of the chamber. An installation location outside the chamber, for example above the entrance location or door, has the advantage that interference and harmful effects caused by high temperatures and temperature changes, dust, moisture, which may foul the camera lens, and infrared radiation reflected by the product, object or chamber wall are largely avoided.

In particular, the mounting position outside the cavity provides the possibility of obtaining a top view and a contour line of the article during the placing of the article and the object into the cavity. The mounting position at the upper part of the cavity, approximately half the depth of the cavity, provides the possibility of obtaining additional top views and contours during heating of the product. Such additional top view and contour lines of the article can be used to further optimize the self-heating article. For example, the corresponding roast state or shape change of the article during addition can be obtained and monitored. This or other parameters often indicate the stage of the heating process.

The contour line device can include: at least one distance sensor designed to measure the distance between said sensor and the level of the upper surface of the article and of the object, respectively; and light emitting means, preferably a laser, more preferably a line laser, designed to illuminate the contours of the article and the object, respectively, by projecting a light beam, preferably a laser line, onto the article and the object, respectively, the projection preferably being performed at a predetermined angle. The light beam may comprise at least one of at least one light ray, at least one fan beam and at least one cone beam. Thus, single point contour-levels, contour-level slices, or contour-level spots may be illuminated. It is noted that, as far as relevant, the aperture angle of the beam can be used to calculate the respective contour lines of the article and the object.

A relatively robust position sensor (e.g., an infrared or ultrasonic distance sensor) may be used to measure the distance between the article and the sensor. The distance may be measured during the process of placing the article in the oven. Such a distance represents the outline of the article and is correlated with the top view or with several top views to calculate article features such as the cross-sectional profile, volume, shape of the article or the height of the article.

As mentioned above, not only the distance sensor but also the light-emitting means or even the distance sensor together with the light-emitting means can be used together with one or more cameras to acquire the product features. The light emitting device, laser and line laser may be used to project a beam or line of laser light onto the respective article and object, respectively, thereby illuminating the contour of at least a portion of the article or object. The illuminated contour line of the contour of the article or a part of the contour of the article can be taken from a top view of the article by using light-emitting means which emit a light beam of, for example, green or red, for example, by means of an image processing method.

The illuminated contours may be identified on the top view of the article based on the respective specific or characteristic color or gray scale level of the light beam or laser line. Similarly, the contour lines obtained by using the light emitting device and the top view of the article may be combined together to calculate at least one article feature. Multiple top views of the article containing the illuminated outline can be recorded during placement of the article into the cavity, and the article views can be combined together to accurately calculate the desired article features. It should be mentioned that triangulation techniques can be used to calculate the contour lines, for example if the starting point and the angle of incidence of the beam or laser line, respectively, are known. However, other methods may be used.

If the initial temperature of the article (i.e., the temperature of the article prior to heating) is known, then the article can be more accurately self-heated. The initial temperature may be used, for example, to select a predetermined heating protocol from a list of given heating protocols.

For example, the initial temperature and the article characteristic "surface area" may be used to estimate, calculate, or predict the energy consumption of the article during heating.

Further, for example, the initial temperature or temperature profile may be used to classify the product as frozen, refrigerated, or non-frozen.

Thus, it is advantageous if the oven further comprises at least one temperature sensor adapted to measure at least one of an initial temperature and an initial temperature profile of the article. The term "initial temperature" shall refer to the temperature prior to heating. Such a temperature sensor may be of the infrared type. Notably, the automatic heating may be further refined by using the temperature values measured during heating.

In order to reduce the effects of heating the product, especially in the case of a cavity in an oven with a temperature of 200 ℃ or more, it may be advantageous if the temperature sensor is mounted outside said cavity.

However, a durable temperature sensor may be used and mounted within or on a wall of the cavity. Such a position makes it possible to track the temperature of the product during heating, which can be used to optimize the automatic heating as already described above.

Especially for ovens, it has been shown that a sensor mounted outside the cavity and above or above the opening makes it possible to measure the initial temperature or other parameters in almost any environment and for almost any product type. This is due to the fact that the top side of the article is rarely hidden or covered during the placing in process and thus various measurements can almost always be made. However, other suitable mounting locations are possible.

Depending on the location of the temperature sensor, an initial temperature or temperature profile may be measured in at least one of before, during, or after the article is placed in the cavity. It is advantageous if the point in time of the initial temperature measurement is close to the starting point of the heating program.

Another important parameter for self-heating is the weight of the article. It is therefore advantageous if the oven further comprises at least one weight sensor for measuring and determining at least one of the weight of the respective article and object.

For example, if the weight of an object (e.g., a pallet) is known, the net weight of the article can be calculated. If the article characteristic "volume" of the article is known or calculated in advance, the weight is used to calculate the density of the article.

The weight sensor can also be used to determine the time course progression of the product weight during the heating process. The time course of the weight of the article can be used to further refine the auto-heating.

It should be mentioned that the oven may also be provided with a function for weight input by the user.

The furnace according to the invention makes it possible to carry out the method of operating the furnace more reliably and accurately in an automated manner. In a second aspect of the invention, a method of operating the furnace is provided.

The method comprises the following steps:

a) obtaining article characteristics of an article to be heated in the cavity of the oven by;

-recording at least one top view of the article via at least one camera;

-acquiring or illuminating with at least one contour line device at least one of a contour line of at least a part of the food product and, as the case may be, a contour line of an object to be placed into the cavity together with the food product; and

-acquiring at least one article feature based on the top view and the contour line; and

b) heating of the article is automatically controlled or performed based on the at least one article characteristic and optionally auxiliary data indicative of the physical configuration of the article, the auxiliary data preferably being at least one of the article temperature, the article weight, and the article density.

Reference is made to the explanations directed to said first aspect of the invention. The method according to said second aspect of the invention thus provides the possibility of automatically heating the product in a particularly accurate and reliable manner.

Top view of the article, contour lines, article features, auxiliary data, etc. may be obtained as described further above. Reference is therefore made to the corresponding explanations with respect to said first aspect of the invention.

In order to capture certain article features, if at least part of the article is recorded in a two-dimensional article top view, the two-dimensional article top view is preferably recorded with the article completely in the field of view of the camera. Such a record may be useful in identifying the article in the corresponding view. The recorded results may be used to calculate an edge, boundary, or perimeter of the article. Additional data retrieved from the record (i.e., recorded article data, such as the length or diameter of the article) may be used to calculate certain article characteristics.

Where only a partial contour line is available for each of the article and object, additional contour lines may be approximated based on the available contour lines. The additional contour lines facilitate article feature acquisition.

The limited field of view and detection range may lead to a limited number of contours, which may, however, also be intentional. In addition, improper product placement may result in a limited number of contours.

Similarly, if only a portion of the article is recordable in the top view of the article, the entire article may be reconstructed based on at least one of the assumptions associated with the article's shape (e.g., symmetry), contour lines, and further approximated contour lines. In addition, only a portion of the recorded data for the article may be compared to the shape or form of the article typical for the corresponding oven and associated method. Here, a typical product shape database may be used.

In many cases, the object is a tray or dish on which the article is placed and on which it rests during heating. The profile, in particular the cross-sectional profile, of the product can be more easily obtained if the tray height or the dish height, i.e. the height occupied by the tray or the dish in the cavity, is automatically determined. Likewise, this may be done based on the tray or tray outline (i.e., the outline identified as belonging to the tray or tray). This also applies to the case where several objects are put in with the product. For example, the article may be positioned on or in a dish, cup, or jar, which is then placed on a tray. Previously known information (e.g., weight, height, etc.) of the corresponding object or objects may be used for article characteristic acquisition. It should be mentioned that the tray height is generally limited to a given number of possible tray heights.

Drawings

The invention will be described in further detail with reference to the accompanying drawings, in which:

fig. 1 shows a schematic side section view of an oven of a first embodiment;

fig. 2 to 4 show schematic side sectional views at different points in time during the placing of the tray into the baking chamber of the oven together with the food product;

FIG. 5 is a top view of an article;

FIG. 6 shows a graph of distance measured by a distance sensor;

fig. 7 shows a schematic side section view of an oven in a second embodiment;

FIG. 8 shows a top view of an article including a contour line illuminated;

fig. 9 shows a projection of a laser line representing an illuminated contour.

Detailed Description

It should be noted that the same reference numerals indicate the same or similar components or components that are functionally similar. The figures are schematic and not necessarily to scale. The present invention will be described in connection with an oven, but this should not be construed as limiting the scope of the invention. The function of the oven is described only to the extent necessary for understanding the present invention.

Fig. 1 shows a side sectional view of an oven 1 in a first embodiment. Oven 1 includes a baking chamber 2. The toasting cavity 2 is adapted to receive toasted articles 3 positioned on the tray 4 via a toasting cavity opening 5. The oven 1 further comprises a door 6, the door 6 being adapted to close and open the opening 5 as indicated by the double arrow. Fig. 1 shows the situation before the food product 3 is placed.

The oven also comprises a digital camera 7 and a distance sensor 8 of infrared or ultrasonic type. The infrared or ultrasonic waves used for distance measurement are shown by dashed lines and indicated with reference numeral 9.

In this embodiment, the distance sensor 8 is mounted at the entrance position of the toasting cavity opening 5, above the door 6 (when the door is in the closed position). In this position, the distance sensor 8 can be protected from heat, moisture and dust generated during baking of the baked product 3. Therefore, the distance sensor 8 is not exposed to the influence factors that may disturb the distance measurement.

The digital camera 7 is mounted on the upper part of the toasting chamber opening 5 and is located at about half the depth of the toasting chamber 2. This position has the advantage that a top view of baked articles can be recorded for a wide variety of baked article positions within the baking chamber 2. In addition, the top view of the article can be recorded during the baking process.

The mode of operation of oven 1 will be explained in connection with fig. 2 to 4, which fig. 2 to 4 show side sectional views at different points in time of placing tray 4 together with baked products 3 into baking chamber 2.

For example, via a signal indicative of the state of the door 6, the distance sensor 8 may be actuated to initiate a distance measurement. Such a signal may indicate, for example, that the door 6 is open or in a closed state, and may be used to activate or deactivate, respectively, the distance sensor 8. Other signals (e.g. motion signals) and contact sensors that scan the position of the entrance of the toasting chamber 2 for an object to be placed into the toasting chamber 2 may also be used. If such a sensor detects that an object is to be placed, the distance sensor 8 can be actuated to initiate a distance measurement.

In this embodiment, the distance sensor 8 is actuated when the door 6 is opened, which already occurs in the case of fig. 1. After activation, the distance sensor 8 continuously measures the distance during the placement of the food product 3 and the tray 4 into the toasting chamber 2. Said distance represents the distance between the distance sensor 8 and the bottom 10 of the toasting chamber 2, the distance between the distance sensor 8 and the tray 4 or the distance between the distance sensor 8 and the toasted product 3.

In fig. 2, a portion of the tray 4 has passed the distance sensor 8 and the baked product 3 has not passed the distance sensor 8. The distance measured up to this stage represents the height of the tray, i.e. the height of the tray 4 relative to the bottom 10 of the toasting cavity 2. For example, if the height of the tray guides of the side walls of the toasting cavity 2 is known, the tray height can be determined using information of possible tray heights known in advance.

As the tray 4 is further inserted, the baked product 3 will also pass the sensor 8. At this stage, the measured distance represents the local height of the baked product 3. In fig. 3, about half of the baked product has passed the distance sensor 8.

In fig. 4, the tray 4 and baked articles 3 are fully inserted into the toasting chamber 2 with the baked articles 3 in their final ready to toast position. At this stage, the digital camera 7 records a top view of the article, indicated by the dashed line.

Fig. 5 shows an exemplary article top view 11. In this embodiment, the product top view 11 is a two-dimensional view showing the baked product 3 and the portion of the tray 4 associated with the upper viewpoint that is not obscured by the baked product 3. The content of the top view 11 of the article may vary from case to case and depends on the field of view of the camera. The information content of the field of view and thus of the corresponding top view 11 of the article can be varied for different requirements.

The camera 7 may be of the colour type or black and white type. The top view of the article 11 is analyzed using conventional image processing methods to record the baked article 3. Depending on the type of camera 7, the baked product 3 can be recorded using color or grey scale. As a result of the recording, the boundary 12 between the baked product 3 and the tray 4 can be acquired. The boundary 12 may be converted into coordinates, such as cartesian x-y coordinates.

Fig. 6 shows a graph of the distance d measured by the distance sensor 8 during the insertion of a tray. The distance d (ordinate axis) is given in terms of time sequence (abscissa) denoted by reference numeral n, and the unit is arbitrary.

As can be seen from fig. 6, the distance d can be divided into a first distance d1 between the sensor 8 and the bottom 10 of the toasting chamber 2, a second distance d2 between the distance sensor 8 and the tray 4, a third distance d3 between the distance sensor 8 and the toasted product 3.

In particular, the distance d represents the contour (contour-level) of the baked product 3 and the tray 4. Contour lines may be obtained from the distance d using contour line means (not shown, e.g. microelectronic devices). For example, the outline of the height profile (height profile) representing the cross-sectional profile of baked product 3 can be obtained by subtracting distance d2 representing the tray height from each distance d 3. The tray height can be obtained as follows: the top view of the article and the recorded data (e.g., the border) are used to identify the portion of the tray 4 not masked by the baked article 3. The distance d (i.e., the second distance d2) may then be assigned to the respective portion. Alternatively, non-continuous rising and falling edges in the sequence of distances d (e.g., from bottom height to tray height or from tray height to bottom height) may be used to identify the tray height. All this can be done in an automated manner and without user involvement.

An article feature acquisition device (not shown), such as an integral part of a microelectronic device, may be used to combine the baked article contour with the x-y coordinates of the boundary 12 and calculate a vector suitable for acquiring at least one of the surface and volume of the baked article 3. If desired, additional or other article features may be obtained in addition to those previously described.

In this embodiment, only contour lines corresponding to a single cross section of the baked product 3 are taken. In order to calculate the surface and volume from the contour lines, the baked product 3 is assumed to be of a symmetrical shape. To more accurately capture the product features, the baked product 3 can be compared to a database of conventional product shapes based on the top view of the product and the available contour lines. Alternatively, a user interface may be provided to enter article shape information suitable for more detailed capture of article features. Furthermore, several distance sensors 8 can be used to acquire contour lines corresponding to different cross-sectional profiles or slices of the baked product. Also, several cameras may be used. By using more than one distance sensor 8 and camera 7, respectively, it is possible to handle asymmetric product shapes and even situations where several baked products 3 are positioned on the tray 4.

It should be mentioned that further contour lines can be approximated by contour lines obtained as above, for example by interpolation or extrapolation.

The baking of the baked product 4 can be controlled in an automated manner based on the obtained product characteristics. The surface and volume are decisive for the heat dissipation during baking. Thus, the use of at least the aforementioned article features will result in a precise and automated enhanced baking process.

In general, a baking protocol that can be selected from a predetermined plurality of general baking methods can be used as a basis for the automatic baking process. Such a baking protocol may be selected based on the product characteristics or other configuration of the baked product 3.

To further enhance the automatic baking, auxiliary data representing the physical configuration of the baked product 3 may be used. Auxiliary data such as article temperature, particularly initial article temperature, article weight, and article density may be used. To determine the product temperature and the product weight, further sensors, such as a temperature sensor and a weight sensor, respectively, may be used. For example, the temperature sensor may be used to determine a configuration of the baked good, such as frozen, chilled, fresh, or thawed.

It should be mentioned that the distance sensor 8 may also be arranged away from said entrance position of the toasting chamber 2. The temperature sensor 8 may be arranged near or beside the camera 7. In this case, the distance d of only a part of the baked product 3 can be measured. For example, if the distance d of only half of the baked product 3 can be measured, the product characteristics can be acquired under the assumption that the baked product 3 is symmetrical with respect to the height. Notably, there is a general assumption that is refined using information retrieved from the top view of the article.

However, in the aforementioned case (i.e. positioning the distance sensor 8 beside the camera 7), it is more involved to correlate the measured distance d with the baked product 3.

This may be due to the fact that the distance detection may be continued when the tray 4 and the baked products 3 have reached their final position within the baking chamber 2. Thus, it is necessary to acquire the distance measured at the drop-in end position.

In order to acquire the distance at the end position, a sensor generating a signal representing the end position of the deposit can be used. This signal can be used to stop the distance measurement or to indicate the distance d measured at the end position.

Alternatively, the distance d at the end position may be determined using a numerical calculation method.

Assuming that the put-in speed is approximately constant (which does apply for most cases), the distance d at the end position can be calculated (at least well approximated) as follows.

A value of the distance belonging to that part of the tray 4 which is close to the rear wall of the toasting cavity 2 and which is not covered by toasted articles 3 and which has passed the distance sensor 8 during the insertion process can be determined. This can be done by using the results of the automatic tray height recognition and the food product 3 registration, since the distance d between the initial tray height distance and the boundary 12 of the baked product 3 along the linear tray part path can be determined and assigned to the above-mentioned part of the tray 4. The above-mentioned parts of the tray 4 can also be identified in the digital article top view by means of a recording method, for example.

After identifying the portion or tray portion path and the associated distance, the number of pixels of the portion along the tray portion path may be determined. It is noted that the path along which the distance measurement is made can be determined by using information known in advance about the relative distance between the camera 7 and the distance sensor 8 and their respective article specifications (e.g. the field of view of the camera 7 and the position of the sensor head at the distance sensor 8).

After the number of pixels corresponding to the tray part path and the distance d are known, the number of distances (distance to unit pixel ratio) of the unit pixels of the tray part path can be calculated. When the speed of insertion is assumed to be constant, the calculated ratio should also apply to the baked product 3 and the associated distance.

After acquiring the number of baked product pixels belonging to the baked product path immediately following the tray portion path, which can be done using the recorded boundary 12 and pixel positions of the distance sensor 8 or distance sensor head, the effective number of distances d belonging to the baked product path can be calculated and the redundant distances discarded leaving only the relevant distances. Using the top view of the article and all relevant distances, article features (e.g., surface or volume) can be acquired. It is noted that under the assumption that the baked goods are symmetrical, for example, the correlation distances may be mirror symmetrical or generally assigned to corresponding symmetrical positions.

Fig. 7 shows a schematic side sectional view of the oven in a second embodiment. The following description is limited to the point of difference compared with the first embodiment. All features described for the first embodiment should also be applicable to the second embodiment, as long as applicable.

In the second embodiment, the line laser 13 is used instead of the distance sensor. It is noted that more than one line laser 13 or a combination of line lasers 13 and distance sensors 8 is also possible, which the skilled person shall be able to achieve on the basis of the foregoing and the following explanations.

The line laser 13 is positioned above the bake chamber opening 5 and is preferably tilted at a predetermined angle. A camera 7 is also positioned above the bake chamber opening 5 and in the vicinity of the line laser 13.

During the insertion process, the line laser 13 emits a green fan laser line 14, while the camera 7 continuously records the top view 11 of the article. It is noted that the laser line 14 may be any other suitable color. In this embodiment, the camera 7 is of the color type.

The laser line 14 strikes the baked product 3 and thereby illuminates the contour of the baked product 3. This is shown in fig. 8. It is noted that the selection of the baked product 3 as a square is merely for the purpose of simplifying the illustration.

Fig. 8 shows a top view of the article including the illuminated outline of the laser line 14. The green color of laser line 14 can be distinguished from the majority of baked goods 3 and the colors used for the interior walls of tray 4 and baking chamber 2. Thus, a projection of the laser line representing the illuminated outline can be acquired in each product top view 11. Due to the inclination of the line laser 13, the projections of the laser lines are staggered in the top view of the article. It is noted that the view of the camera 7 at the bottom 10 of the toasting chamber 2 is indicated by a dash-dot line and by reference numeral 15.

Fig. 9 shows the laser line projection of fig. 8 after extraction from the top view 11 of the corresponding article. The original dimensions of the recorded top view 11 of the article are indicated by boxes. Laser line projection can be divided into the following: a first projection p1, representing the outline of the bottom 10 of the baking chamber 2; a second laser line projection p2, representing the outline of the tray 4; and a third laser line projection p3 representing the outline of baked product 3.

Based on the laser line projections p1, p2 and p3, local contour lines can be calculated, i.e. the relative heights of the respective positions, i.e. the bottom 10, the tray 4 and the baked product 3. For example, using the tilt angle, the position of the line laser 13, the distance between the respective laser line projection p1-p3 and the center line 16 of the field of view 15, the respective contour line may be acquired by triangulation techniques.

A top view of the article comprising the entire tray 4 and baked article 3 can be used to register the baked article 3 to define the boundary 12. For example, using the pixel resolution of the camera 7, the boundary 12 may be converted to x-y coordinates which, in combination with the acquired contour lines of the baked product 3, may be used to determine surface and volume or other product features.

An advantage of using a line laser 13 according to the second embodiment is that all types of regular and irregular article shapes and the situation of several baked articles 3 of the same or different shapes positioned on a tray 4 can be handled without difficulty.

The use of a linear one-dimensional laser line instead of the fan laser line 14 of the second embodiment corresponds to the case of the first embodiment and is referred to the first embodiment.

As for the second embodiment, the advantages associated with the automatic baking process apply mutatis mutandis.

Although the present invention has been described with respect to oven 1, the present invention may be applied to other types of ovens that may also achieve all of the advantages and benefits.

From the above discussion it is clear that the objects of the invention are achieved by the oven and the method as claimed.

List of reference numerals

1 oven

2 baking chamber

3 baked goods

4 tray

5 opening of baking cavity

6 door

7 digital camera

8 distance sensor

9 infra-red or ultrasonic

10 bottom

11 top view of the article

12 boundary

13 line laser

14 laser line

15 observation area

16 center line

d distance

First to third distances dl, d2, d3

n is a number

pi, p2, p3 first to third laser line projections

Claims (14)

1. Oven (1) for heating a food product (3), comprising:

a cavity (2) adapted to receive a food product (3) via a cavity opening (5); and

product feature acquisition system designed for acquiring at least one product feature representative of a configuration of a food product (3), said system comprising:

-at least one camera (7) designed and positioned for recording a top view (11) of the article; and

-at least one contour line device designed and positioned to acquire or illuminate the contour line of at least a portion of the product (4) and, as the case may be, the contour line of an object (4) to be placed into the cavity (2) together with the food product (3); and

-an article feature acquisition means for acquiring said at least one article feature based on an article top view (11) and said contour line.

2. Furnace (1) according to claim 1, wherein the mounting position of the at least one camera (7) and the at least one contour line device is selected from the group consisting of: the upper part of the opening (5) is preferably located at the entrance site, above the door (6) closing and opening the opening (5), and the upper part of the chamber (2) is preferably half the depth of the chamber (2).

3. Furnace (1) according to claim 1 or 2, wherein the contour line device comprises:

-at least one distance sensor (8) designed to measure the distance (d) between said sensor (8) and the level of the upper surface of the food product (3) and of the object (4), respectively; and

-at least one light emitting means, designed to illuminate the profile of the food product (3) and the object (4), respectively, by projecting a light beam, preferably at least one laser, more preferably at least one line laser (13), onto the food product (3) and the object (4), respectively, said light beam preferably being a laser line (14), and said light beam preferably being projected at a predetermined angle.

4. Oven (1) according to claim 3, wherein at least one of the at least one distance sensor (8) is an infrared or ultrasonic distance sensor; and wherein at least one of the at least one light emitting means is designed to emit a red or green light beam (14).

5. Oven (1) according to at least one of claims 1 to 4, further comprising at least one temperature sensor for measuring at least one of an initial temperature and an initial temperature profile of the food product (3) and the object (4), respectively, said at least one temperature sensor preferably being an infrared temperature sensor, said at least one temperature sensor preferably being mounted outside said cavity and preferably being located in an upper part of said opening.

6. Oven (1) according to at least one of claims 1 to 5, further comprising a weight sensor for measuring and determining at least one of the weight of the food product (3) and the object (4), respectively.

7. Oven (1) according to at least one of claims 1 to 6, wherein the product features are selected from the group consisting of: vertical cross-section, horizontal cross-section, shape, in particular three-dimensional model, surface area, volume, size, in particular length, width and height of the food product (3), centre of gravity of the food product (3), and distance of the centre of gravity to the surface.

8. A method of operating an oven (1) for heating a food product (3), comprising the steps of:

a) the product characteristics of a food product (3) to be heated in a cavity (2) of an oven (1) are obtained by:

-recording at least one top view (11) of the article via at least one camera (7);

-acquiring or illuminating with at least one contour line device at least one of a contour line of at least a part of the food product (3) and, as the case may be, a contour line of an object (4) to be placed into the cavity (2) together with the food product (3); and

-acquiring at least one article feature based on the top view (11) and the contour line; and

b) heating of the food product (3) is automatically controlled or performed based on the at least one product characteristic and optionally auxiliary data indicative of the physical configuration of the food product (3), preferably at least one of product temperature, product weight, product density.

9. The method according to claim 8, wherein the at least one portion of the food product (3) is recorded within a two-dimensional product top view (11); and wherein the acquisition of the at least one product characteristic is further effected based on the recorded product data, preferably the edge, border (12) or periphery of the food product (3).

10. The method according to at least one of claims 8 and 9, wherein the step of obtaining contour lines comprises: the distance (d, d1, d2, d3) between the at least one position sensor (8) and the height of the upper surface of the food product (3) and the object (4), respectively, is measured by at least one distance sensor (8), which is preferably designed to measure the distance (d, d1, d2, d3) via infrared or ultrasound.

11. The method according to at least one of claims 8 to 10, wherein the step of illuminating the contour lines comprises: the outline of the food product (3) and the object (4) is illuminated by projecting at least one light beam, preferably a laser line (14), preferably at least one of green and red, preferably at a predetermined angle, onto said food product (3) and object (4), respectively.

12. Method according to at least one of claims 8 to 11, wherein further contour lines for enhancing the product feature acquisition are approximated based on available contour lines, preferably by extrapolation or interpolation.

13. The method according to at least one of claims 8-12, wherein the object is a tray (4) for placing a food product (3) thereon; and wherein the tray height is automatically determined based on the tray contour.

14. The method according to at least one of claims 8-13, wherein the article characteristics are selected from the group consisting of: vertical cross-section, horizontal cross-section, shape, in particular three-dimensional model, surface area, volume, size, in particular length, width and height of the food product (3), centre of gravity of the food product (3), and distance of the centre of gravity to the surface.