METHOD FOR RECOGNISING A MOTION WITHIN A TREATMENT CHAMBER OF A DOMESTIC APPLIANCE

The present invention relates to a method for recognising a mo tion within a treatment chamber of a domestic appliance. In par ticular, the present invention relates to a method for recognis ing a creature, for example a pet, within a treatment chamber of a domestic appliance. Further, the present invention relates to a domestic appliance with a treatment chamber and a camera di rected to said treatment chamber, wherein the domestic appliance is adapted for recognising a motion, in particular by a creature like a pet, within the treatment chamber.

There are situations, in which a pet or another animal may be located within a treatment chamber of a domestic appliance. For example, children bother a pet and imprison it within an oven cavity of a cooking oven. Further, the pet may use a laundry drum of a washing machine or dryer as sleeping place. When the pet is in the treatment chamber and the operation of the domes tic appliance is started, then said pet may be injured or killed. It is an object of the present invention to provide a reliable method for recognising the presence of a creature within the treatment chamber of the domestic appliance by low complexity.

The object is achieved by the method according to claim 1.

According to the present invention a method for recognising a motion, in particular by a creature like a pet, within a treat ment chamber of a domestic appliance is provided, wherein the method comprises the steps of: detecting an image of the interior of the treatment chamber, detecting at least one further image of the interior of the treatment chamber after a predetermined time-lag, comparing the detected images or functions of said detected images, if the detected images or the functions of the detected im ages, respectively, are identical, then the operation of the domestic appliance is started or unlocked, and if the detected images or the functions of the detected im ages, respectively, differ from each other, then the opera tion of the domestic appliance is blocked or stopped and/or an alarm signal is output.

The core of the present invention is that the motion in the treatment chamber is recognised by detecting two or more images of said treatment chamber. The detected images or functions of said detected images are compared. Differing images or func tions, respectively, indicate a motion and the presence of a creature within the treatment chamber. By this way, a pet in the treatment chamber can be recognised. The blocking of the opera tion of the domestic appliance prevents that the creature is in jured or killed.

For example, the time-lag between two subsequent detections of images and is from 0.1 s to 5.0 s, in particular from 0.2 s to 2.0 s, preferably from 0.3 s to 1.0 s, more preferably 0.5 s.

According to one embodiment of the present invention the follow ing steps are provided: detecting at least three images of the interior of the treatment chamber, calculating at least two differences of subsequently de tected images in each case, comparing the calculated differences of the detected images, if the calculated differences of the detected images are identical, then the operation of the domestic appliance is started or unlocked, and if the calculated differences of the detected images differ from each other, then the operation of the domestic appli ance is blocked or stopped and/or an alarm signal is output.

According to a further embodiment of the present invention the following steps are provided: - detecting at least three images of the interior of the treatment chamber, calculating at least two differences of subsequently de tected images in each case, and modifying the calculated differences of the detected images by a maximum noise level relating to at least one device for detecting the images.

For example, first modified differences are given by subtracting the maximum noise level from the calculated differences in each case.

In this case, the method comprises the steps of: comparing the first modified differences, if the first modified differences are identical, then the operation of the domestic appliance is started or unlocked, and if the first modified differences differ from each other, then the operation of the domestic appliance is blocked or stopped and/or an alarm signal is output.

Further, second modified differences may be given by adding the maximum noise level to the calculated differences in each case.

In that case, the method comprises the steps of: comparing the second modified differences, if the second modified differences are identical, then the operation of the domestic appliance is started or unlocked, and - if the second modified differences differ from each other, then the operation of the domestic appliance is blocked or stopped and/or an alarm signal is output.

A combined method comprises the steps of: - comparing the first modified differences, comparing the second modified differences, if the first modified differences are identical and the sec ond modified differences are identical, then the operation of the domestic appliance is started or unlocked, and - if the first modified differences or the second modified differences differ from each other, then the operation of the domestic appliance is blocked or stopped and/or an alarm signal is output. For example, the alarm signal is an optical and/or acoustic sig nal and/or a message to a remote control device.

In particular, the images are detected by at least one camera. Often, a camera directed to the treatment chamber is already present in the domestic appliance.

Preferably, the images being compared or used for the calcula tion of the differences or modified differences are detected by the same camera or cameras, respectively.

Moreover, the parameters, e.g. white balance, contrast and brightness, of the camera may remain constant during the detec tion of the images. Further, the present invention relates to a domestic appliance with a treatment chamber and a camera directed to said treatment chamber, wherein the domestic appliance is adapted for perform ing the method mentioned above.

For example, the domestic appliance is a cooking oven, a micro- wave oven, a dishwasher, a washing machine and/or a laundry dryer.

Novel and inventive features of the present invention are set forth in the appended claims.

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

FIG 1 illustrates a schematic flow chart diagram of a method for recognising a motion within a treatment chamber of a domestic appliance according to a first embodiment of the present invention,

FIG 2 illustrates a schematic flow chart diagram of the method for recognising the motion within the treatment chamber of the domestic appliance according to a second embodi ment of the present invention, and

FIG 3 illustrates a schematic flow chart diagram of the method for recognising the motion within the treatment chamber of the domestic appliance according to a third embodiment of the present invention.

FIG 1 illustrates a schematic flow chart diagram of a method for recognising a motion within a treatment chamber of a domestic appliance according to a first embodiment of the present inven tion. In particular, the method is provided for recognising a creature like a pet within the treatment chamber of the domestic appliance.

In a first step 10 the method of recognising the motion within the treatment chamber is started. Next, a first image Img(1) of the interior of said treatment chamber is detected in step 12. Then, a second image Img(2) of the interior of the treatment chamber is detected in step 14. At last, an n-th image Img(n) of the interior of said treatment chamber is detected in step 16.

In general, two or more images Img(1) to Img(n) of the interior of the treatment chamber are detected. The time-lag At between two subsequent detections of images Img(1) to Img(n) and is from 0.1 s to 5.0 s, in particular from 0.2 s to 2.0 s, preferably from 0.3 s to 1.0 s, more preferably 0.5 s.

For example, the images Img(1) to Img(n) are detected by a cam era directed to the interior of the treatment chamber. In par ticular, the images Img(1) to Img(n) are detected by the same camera. Further, the parameters, e.g. white balance, contrast and brightness, of the camera remain constant during the detec tion of the images Img(1) to Img(n).

In a further step 18 the detected images Img(1) to Img(n) are compared. If the detected images Img(1) to Img(n) are identical, then an operation of the domestic appliance is started in step 26 or at least unlocked. However, if at least one of the de tected images Img(1) to Img(n) differs from the other detected images Img(1) to Img(n), then the operation of the domestic ap pliance is blocked in step 28.

The differing detected images Img(1) to Img(n) indicate a motion within the treatment chamber of the domestic appliance. In par ticular, the differing detected images Img(1) to Img(n) allow the recognition of a pet enclosed within the treatment chamber. FIG 2 illustrates a schematic flow chart diagram of the method for recognising the motion within the treatment chamber of the domestic appliance according to a second embodiment of the pre- sent invention.

In the first step 10 the method of recognising the motion within the treatment chamber is started. The first image Img(1) of the interior of said treatment chamber is detected in step 12 and the second image Img(2) of the interior of the treatment chamber is detected in step 14, until the n-th image Img(n) of the inte rior of said treatment chamber is detected in step 16. Gener ally, three or more images Img(1) to Img(n) of the interior of the treatment chamber have to be detected, wherein the time-lag At between two subsequent detections of images Img(1) to Img(n) and is from 0.1 s to 5.0 s, in particular from 0.2 s to 2.0 s, preferably from 0.3 s to 1.0 s, more preferably 0.5 s.

Preferably, the images Img(1) to Img(n) are detected by the same camera, wherein the parameters, e.g. white balance, contrast and brightness, of said camera remain constant during the detection of the images Img(1) to Img(n).

In a further step 20 the differences Dif (1) to Dif(n-l) between two subsequently detected images Img(1) to Img(n) in each case are calculated. Then, the calculated differences Dif (1) to Dif(n-l) are compared to each other in step 22.

If the calculated differences Dif (1) to Dif(n-l) are identical, then the operation of the domestic appliance is started in step 26 or at least unlocked. However, if at least one of the calcu lated differences Dif (1) to Dif(n-l) differs from the other calculated differences Dif (1) to Dif(n-l), then the operation of the domestic appliance is blocked in step 28. The differing calculated differences Dif (1) to Dif(n-l) indi cate a motion within the treatment chamber of the domestic ap pliance. In particular, the differing calculated differences Dif (1) to Dif(n-l) allow the recognition of a pet enclosed within the treatment chamber.

FIG 3 illustrates a schematic flow chart diagram of the method for recognising the motion within the treatment chamber of the domestic appliance according to a third embodiment of the pre sent invention.

In the first step 10 the method of recognising the motion within the treatment chamber is started. The first image Img(1) of the interior of said treatment chamber is detected in step 12 and the second image Img(2) of the interior of the treatment chamber is detected in step 14, until the n-th image Img(n) of the inte rior of said treatment chamber is detected in step 16. Gener ally, three or more images Img(1) to Img(n) of the interior of the treatment chamber have to be detected, wherein the time-lag At between two subsequent detections of images Img(1) to Img(n) and is from 0.1 s to 5.0 s, in particular from 0.2 s to 2.0 s, preferably from 0.3 s to 1.0 s, more preferably 0.5 s. Preferably, the images Img(1) to Img(n) are detected by the same camera, wherein the parameters, e.g. white balance, contrast and brightness, of said camera remain constant during the detection of the images Img(1) to Img(n). In the further step 20 the differences Dif (1) to Dif(n-l) be tween two subsequently detected images Img(1) to Img(n) in each case are calculated. Then, the calculated differences Dif (1) to Dif(n-l) are modified in two ways and then compared to each other in step 24. The first modified differences are the calcu lated differences Dif (1) to Dif(n-l) subtracted by a maximum noise level NLmax of the camera in each case. The second modi fied differences are the calculated differences Dif (1) to Dif(n-l) added by said maximum noise level NLmax of the camera in each case. Then, the first modified differences are compared to each other in step 24. In a similar way, the second modified differences are compared to each other in step 24. If the first modified differences are identical to each other and also the second modified differences are identical to each other, then the operation of the domestic appliance is started in step 26 or at least unlocked. However, if at least the first modified dif ferences deviate from each other or at least the second modified differences deviate from each other, then the operation of the domestic appliance is blocked in step 28.

The deviating modified differences indicate a motion within the treatment chamber of the domestic appliance. In particular, the deviating modified differences allow the recognition of a pet enclosed within the treatment chamber.

In particular, the domestic appliance is a cooking oven, a mi crowave oven, a dishwasher, a washing machine and/or a laundry dryer. For example, the treatment chamber may be an oven cavity or a laundry drum.

Preferably, the method for recognising the motion within the treatment chamber is performed before the operation of the do mestic appliance. Additionally or alternatively, the method for recognising the motion within the treatment chamber may be per formed during the operation of the domestic appliance, if said operation itself does not involve any motion of or inside the treatment chamber. In the latter case, the operation of the do mestic appliance is automatically stopped and/or an alarm signal is output. Said alarm signal may be an optical and/or acoustic signal and/or a message to a remote control device.

Although illustrative embodiments of the present invention have been described herein with reference to the accompanying draw ings, it is to be understood that the present invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the in- vention. All such changes and modifications are intended to be included within the scope of the invention as defined by the ap pended claims.

List of reference numerals

10 starting method

12 detecting first image

14 detecting second image

16 detecting n-th image

18 comparing detected images

20 calculating differences of subsequent images

22 comparing differences

24 comparing modified differences

26 starting operation

28 blocking operation

At time-lag

Img (1) first image Img (2) second image Img (n) n-th image Dif (1) difference between second and first image Dif (2) difference between third and second image Dif (n) difference between (n+l)-th and n-th image

NLmax maximum noise level