WO2019091741A1

WO2019091741A1 - An oven

Info

Publication number: WO2019091741A1
Application number: PCT/EP2018/078550
Authority: WO
Inventors: Murat Kantas
Original assignee: Arcelik Anonim Sirketi
Priority date: 2017-11-07
Filing date: 2018-10-18
Publication date: 2019-05-16
Also published as: TR201717412A2

Abstract

The present invention relates to an oven detecting whether the food placed therein is cooked, characterized by at least one control unit receiving data provided by the sensor, obtaining color data based on said data, and deternnining whether the food in the chamber is cooked by interpreting said color data.

Description

AN OVEN

Technical Field

The present invention relates to an oven detecting whether the food placed therein is cooked.

Prior Art

The cooking process completes when the cooked food reaches a desired level of roast, texture, surface color, etc. Cooking of a food product is usually terminated upon the surface color of the product reaching a desired color. In order to measure the surface color of cakes and similar pastries, a color scale is used, referred to as BSI (British Standard Institution) Shade Gauge scale. This scale designates values in the range of 4 to 17.

The state of cooking can be determined in an oven illuminated with a fixed light source, having a camera module therein, by taking photographs in determined periods and properly image processing said photographs.

During cooking, the state of cooking and when cooking should be terminated can be determined by monitoring the color change of the pastry in the oven and matching its color with the color scale standards. Generally, the RGB (Red-Green-Blue) color scale is used for processing photographs. However, this color scale is not sufficient to filter the desired color ranges and to define the change of color in a given range.

In RGB color space, each color differs depending on its red, blue and green content. In the RGB scale, colors range between 0.0.0 (black) and 255.255.255 (white).

Examining the RGB codes of two colors which seem to be very similar tones of brown, reveals that they exhibit simultaneous changes in their red, blue and green contents. It is difficult to determine that these colors are similar just by looking at their color codes. Filtering the tones of brown in a given RGB range is not possible due to the fact that all of the three main colors (red, green and blue) exhibit changes during transition from a color to a similar color tone.

State of the art United States patent document no. US 20120076351 mentions an oven capable of determining the state of cooking. In said oven, photographs are taken in given intervals and these photographs are evaluated according to the RGB color scale.

State of the art European patent document no. EP2149755 mentions an oven calculating the volume of the food being cooked and determining whether cooking is completed according to this volume,

None of the state of the art documents include a solution such as the one in the present invention.

Brief Description of the Invention

The aim of the present invention is to realize an oven detecting whether the food placed therein is cooked.

Another aim of the present invention is to realize an oven detecting whether the food placed therein is cooked by checking the color of said food.

Detailed Description of the Invention

The oven realized to achieve the aims of the present invention is illustrated in the accompanying drawing, wherein:
Figure 1: is a graph of the BSI color values corresponding to the L value in the range of determined a b limit values.

The oven detecting whether the food placed therein is cooked, comprises

at least one chamber in which the foods desired to be cooked are placed,
at least one light source enabling illuminating inside the chamber,
at least one sensor enabling taking images or receiving color data from within the chamber, and
at least one control unit receiving data provided by the sensor, obtaining color data based on said data, and determining whether the food in the chamber is cooked by interpreting said color data.

A user places the food which he/she desires to cook, in the chamber. The interior of the chamber is illuminated by means of the light source. Thus, the detection process performed by the sensor is enabled always to take place under identical lighting conditions. The light source may continuously illuminate the interior of the chamber, or may only illuminate when the sensor has to perform the detection process. The sensor is preferably a camera, but a color sensor may also be used as the sensor in an embodiment of the invention. The sensor transmits the data it obtains to the control unit. The control unit processes the data received from the sensor, obtaining a color data. The output of sensors is usually according to RGB color scale, therefore the control unit converts this output according to CIE L*a*b color space. If the used sensor is a camera, then said conversion is preferably applied to each pixel of an image. Then the control unit filters said image for the a and b values obtained from the BSI Shade Gauge scale. Filtering is preferably performed in the range of -20<a<10 and 0<b<78, which covers all colors in the BSI Shade Gauge scale. After filtering, the average of the L (lightness) values of the regions remaining within the determined a and b values, is calculated, thereby obtaining the BSI values corresponding to the determined ranges. The cooking state of the food being cooked is determined by means of said values. When the obtained BSI values reach a predetermined level, the control unit generates a notifying signal output. In accordance with said signal output, cooking may be terminated automatically and/or the user may be alerted audibly and/or visibly. Different signal outputs may be generated to terminate cooking, to alert the user visibly or to alert the user audibly.

In an embodiment of the invention, the control unit converts the information in RGB color space received from the sensor, first to the XYZ color space and then to the L*a*b color space. However, the information in RGB color space may also be converted directly to the L*a*b color space in another embodiment.

In an embodiment of the invention, the light source preferably emits light in 6500K which is almost the color temperature closest to day light. Preferably, this light is distributed homogeneously in the chamber.

The image detected by the sensor can be filtered according to the colors of the BSI scale thanks to using L*a*b space as the color space. Thus, the processing power required to process images can be reduced and an image can be processed more accurately.

Claims

An oven detecting whether the food placed therein is cooked, comprising

- at least one chamber in which the foods desired to be cooked are placed,

- at least one light source enabling illuminating inside the chamber,

- at least one sensor enabling taking images or receiving color data from within the chamber, characterized by

- at least one control unit receiving data provided by the sensor, obtaining color data based on said data, and determining whether the food in the chamber is cooked by interpreting said color data.
An oven according to claim 1, comprising a control unit converting the obtained color data according to the CIE L*a*b color space.
An oven according to claim 2, comprising a control unit filtering the colors converted according to the L*a*b color space for the a and b values obtained from the BSI Shade Gauge scale.
An oven according to claim 3, comprising a control unit calculating the average of the L (lightness) values of the filtered colors, thereby obtaining the BSI values corresponding to the determined ranges.
An oven according to claim 4, comprising a control unit generating a signal output in order to enable automatically termination of cooking upon the obtained BSI values reaching a predetermined level.
An oven according to claim 4, comprising a control unit generating a signal output in order to enable alerting the user visibly and/or audibly upon the obtained BSI values reaching a predetermined level.
An oven according to claim 2, comprising a control unit converting the information in RGB color space received from the sensor, first to the XYZ color space and then to the L*a*b color space.
An oven according to claim 1, comprising a light source emitting light in a temperature of 6500K which is almost the color temperature closest to day light.