JPWO2018235703A1 - Heating cooker - Google Patents

Abstract

A heating chamber (12) for storing the object to be heated, a magnetron (13) for heating the object to be heated stored in the heating chamber (12), and a camera (16) for photographing the inside of the heating chamber (12), A reading unit (19) for reading the characters of the heating control information given to the object to be heated, and a heating control unit (14) for controlling the magnetron (13) based on the heating control information read by the reading unit (19). And are equipped with. The distance from the camera (16) to the character of the heating control information is 480 mm or less.

Description

  The present disclosure relates to a cooking device that heats food.

  A microwave oven, which is a typical heating cooker, can heat food in a container without using a pan and a frying pan. Then, in a store that sells bento and side dishes in a container, a salesclerk uses a microwave oven to heat and provide the purchased food.

  This service will be described. Generally, the optimum heating time for heating in a microwave oven is displayed on lunch boxes and side dishes. Then, the sales clerk at the store looks at the display, sets the heating time with the microwave oven, and heats it. Numeric keys and the like are provided on the operation unit of the microwave oven, and the heating time (minutes, seconds) can be manually set.

  In some cases, the microwave oven has a plurality of operation buttons, and each operation button is assigned a different heating time. The store clerk selects the button corresponding to the food to be heated. As a result, the food or the like is heated by heating control suitable for the food and provided to the customer.

  When the heating time (minutes, seconds) is set by the numeric keys as in the former configuration, the number of operations is large, and thus a complicated operation may be required. In the latter configuration, that is, in the case where different heating times are assigned to each of the plurality of operation buttons, the clerk will remember the correspondence between the buttons and the heating time as the number of types of food increases. Can be difficult.

  In order to eliminate these annoyances and mistakes, the heating cooker stores the heating control content for each product in advance, and the salesclerk at the store uses the bar code reader to read the code information of the product and heat it. A method has been proposed in which the cooker calls the heating control content corresponding to the product from the code information and performs appropriate heating.

  Further, instead of using a bar code reader, the microwave oven is equipped with a camera for photographing the inside of the refrigerator, the barcode portion is extracted from the image of the product placed in the refrigerator, and the barcode is read. As a result, the heating control content corresponding to the product is called from the code information, and appropriate heating is performed. According to this method, the operation load on the store clerk can be reduced, and it is possible to provide an error-free heating service (for example, refer to Patent Document 1 and Patent Document 2 described later).

JP, 2001-349546, A International Publication No. 2016/143267

  The present disclosure provides a heating cooker that enhances the reading accuracy of characters including heating control information and the like.

  A heating cooker according to the present disclosure includes a heating chamber in which an object to be heated is housed, a heating unit that heats the object to be heated housed in the heating chamber, an imaging unit that captures an image of the inside of the heating chamber, and an object to be heated. A reading unit that reads the characters of the generated heating control information and a heating control unit that controls the heating unit based on the heating control information read by the reading unit are provided. The distance from the imaging unit to the characters of the heating control information is 480 mm or less.

  With such a configuration, in the heating chamber of the heating cooker, the characters attached to the object to be heated are separated from the imaging unit, and the characters of the heating control information applied to the object to be heated are read by the reading unit. It is possible to minimize the possibility of the problem of not being recognized. Therefore, it is less likely that the heating cannot be started because the characters of the heating control information are not recognized. Further, it is possible to minimize the troublesome work such as the user opening the door of the heating cooker and changing the placement position of the object to be heated.

FIG. 1 is a perspective view showing an external appearance of a microwave oven which is an example of a heating cooker according to an embodiment of the present disclosure. FIG. 2A is a diagram showing a schematic configuration of a microwave oven according to the embodiment of the present disclosure. FIG. 2B is a diagram showing a schematic configuration of the inner wall of the heating chamber of the microwave oven according to the embodiment of the present disclosure. FIG. 3 is a diagram showing an example of a seal attached to a product in the embodiment of the present disclosure. FIG. 4 is a diagram showing an example of the position designation mark displayed on the sticker according to the embodiment of the present disclosure. FIG. 5A is a plan view showing a state where the bottom surface of the heating chamber is viewed from above in the embodiment of the present disclosure. FIG. 5B is a plan view showing a state where a product is placed in a state where the bottom surface in the heating chamber is viewed from above in the embodiment of the present disclosure. FIG. 5C is another plan view showing a state where the bottom surface in the heating chamber is viewed from above in the embodiment of the present disclosure. FIG. 6 is a schematic diagram showing an example of the inner wall of the heating cabinet of the microwave oven when the camera is installed substantially in the center of the upper surface of the heating cabinet in the embodiment of the present disclosure. FIG. 7 is a diagram showing the relationship between the distance from the camera to the subject and the degree of blur in the embodiment of the present disclosure. FIG. 8 is a diagram showing a relationship between the horizontal resolution and the vertical resolution and the distance from the camera to the subject in the embodiment of the present disclosure. FIG. 9 is a diagram showing the relationship between the distance from the lens of the imaging unit to the character of the heating control information and the recognition resolution in the embodiment of the present disclosure. FIG. 10 is a flowchart showing an operation flow of the heating control unit, the reading unit, and the error determination unit in the embodiment of the present disclosure.

(Findings that form the basis of this disclosure)
In general, bar codes are attached to bento boxes, side dishes, etc. sold at stores. The information contained in this bar code is information for identifying products such as bento and side dishes, and does not contain information on heating time. Therefore, in order to recognize the barcode and automatically set the heating time, the correspondence between the product and the heating time needs to be registered in advance in the microwave oven.

  The number of merchandise handled by dealers such as bento and side dishes that are heated in a microwave oven is very large. In addition, there is a case where a new product comes out daily or weekly and is replaced with the old product, and the work of constantly registering the correspondence between the new product and the heating time in the microwave oven continues to occur.

  In addition, some large-scale stores are equipped with a plurality of microwave ovens so that a plurality of products can be simultaneously heated in parallel. In this case, it is necessary to perform the work of registering the correspondence between the code specifying the product and the heating time for all of the plurality of microwave ovens, and the annoyance cannot be said to be solved.

  In addition, at a store, a plurality of products may be purchased at the same time. In this case, the store clerk has to put the products in the microwave oven one by one and repeat the work of reading the barcode, which does not solve the annoyance.

  Also, when the store clerk puts the product in the microwave oven and closes the door and then tries to start reading the bar code, if the bar code reading fails, the store clerk opens and closes the door. It is not possible to say that the annoyance can be solved because the product must be replaced frequently.

  Therefore, the clerk can automatically set the heating time without inputting the heating time of the product or selecting the button corresponding to the product, and register the relationship between the product code and the heating time. However, a technique that does not require a troublesome work has been proposed.

  That is, in the heating cooker, an imaging unit that captures an image of the inside of the heating chamber, a reading unit that extracts and reads the characters of the heating control information from the pasted object pasted on the object to be heated, and the heating control read by the reading unit The heating unit is controlled based on the information (see, for example, Patent Document 2).

  However, with this configuration, the characters attached to the object to be heated may not be accurately read by the imaging unit. The focus range of the camera is prescribed, and if it goes out of the focus range, the image will be blurred, making it difficult to read it accurately. In particular, in the heating chamber of the heating cooker, the characters are attached to the object to be cooked and the distance from the shooting unit is out of focus and the distance is farther away, the smaller the characters are and the more blurred they are. . Therefore, the possibility of correctly recognizing the character decreases. On the other hand, if the distance between the characters attached to the object to be heated and the image capturing unit deviates from the in-focus range but is closer to the distance, the characters will be blurred, but will be photographed larger. Therefore, it is possible to maintain high character recognition accuracy as compared with the case where it is difficult to recognize a character far away from the range in focus.

(One example of possible aspects of the present disclosure)
A first aspect of the present disclosure relates to a heating chamber in which an object to be heated is stored, a heating unit for heating the heating target stored in the heating chamber, an imaging unit for photographing the inside of the heating chamber, and an object to be heated. A reading unit that reads the characters of the applied heating control information and a heating control unit that controls the heating unit based on the heating control information read by the reading unit are provided. The distance from the imaging unit to the characters of the heating control information is 480 mm or less.

  With such a configuration, the characters attached to the object to be heated are separated from the image capturing unit in the heating chamber of the heating cooker, and the characters of the heating control information applied to the object to be heated are read by the reading unit. It is possible to minimize the possibility of not being recognized by. Therefore, it is rare that the characters of the heating control information are not recognized and the heating cannot be started, and the user opens the door of the heating cooker and changes the placement position of the object to be heated, which is troublesome. The work can be reduced as much as possible.

  In a second aspect, in the first aspect, a marker is provided in the heating chamber for designating a place where the object to be heated is placed at a place where the distance from the imaging unit to the characters of the heating control information is 480 mm or less. It may be configured.

  According to this configuration, when the user places the object to be heated in the heating chamber of the heating cooker, it is possible to guide the user to place the object to be heated in a place where the reading unit can easily read it. Then, in the heating chamber of the heating cooker, the reading unit may not be able to recognize the characters of the heating control information given to the object to be heated due to the distance between the characters given to the object to be heated and the imaging unit. Can be made as small as possible. Therefore, it is possible to reduce the possibility that heating cannot be started without recognizing the characters of the heating control information, and the user opens the door of the heating cooker and changes the placement position of the object to be heated, etc. Can be minimized.

  In the third aspect, in the first aspect or the second aspect, the dimensions inside the heating chamber may be a width of 350 mm or less, a depth of 320 mm or less, and a height of 200 mm or less.

  According to such a configuration, further, in the heating chamber of the heating cooker, the character provided to the object to be cooked is separated from the imaging unit, and the character of the heating control information provided to the object to be heated is further separated. The possibility that the reading unit cannot recognize can be minimized. Therefore, it is possible to reduce the possibility that heating cannot be started without recognizing the characters of the heating control information, and the user opens the door of the heating cooker and changes the placement position of the object to be heated, etc. Can be minimized.

In a fourth aspect, in any one of the first aspect to the third aspect, the imaging unit is determined from the character size in a range in which the distance from the imaging unit to the character of the heating control information is 250 mm or less. When the recognition reference resolution (r), the horizontal resolution (h), the vertical resolution (p), the circle of confusion (c), and the pixel size (x) of the image captured by the image capturing unit are set, the following formula is established. May be. (X / c) × (h × p)> r ² .

  According to this configuration, in a relatively narrow space such as the inside of the heating chamber of the heating cooker, the distance between the imaging unit and the characters attached to the object to be heated is within a distance range shorter than a predetermined distance, Regardless of the position of the object to be heated, the accuracy of reading characters including heating control information and the like can be maximized. Further, even when the distance between the character attached to the object to be heated and the photographing unit is considerably short, the accuracy of reading the character including the heating control information can be increased as much as possible.

  In the fifth aspect, in any one of the first to fourth aspects, the distance from the imaging unit to the character of the heating control information may be 90 mm or more.

  According to this configuration, further, when the length of the character including the heating control information or the like that needs to be read is within 50 mm, the reading accuracy of the character including the heating control information or the like can be increased as much as possible.

  In a sixth aspect, in any one of the first to fifth aspects, the viewing angle of the imaging unit may be 31 degrees or more.

  With such a configuration, even if the distance from the imaging unit to the characters of the heating control information is considerably short, the length of the characters that need to be read, including the heating control information, is within 50 mm. If so, the accuracy of reading characters including heating control information can be increased as much as possible.

  Hereinafter, embodiments of the present disclosure will be described. The present disclosure is not limited to these embodiments.

(Embodiment)
An embodiment of the present disclosure will be described.

  FIG. 1 is a perspective view showing an appearance of a microwave oven 1 which is an example of a heating cooker according to an embodiment of the present disclosure.

  As shown in FIG. 1, the microwave oven 1 includes a housing 2 for storing food, and the housing 2 is provided with a door 3 for loading and unloading food. The door 3 is provided with a transparent glass window 4 for allowing the inside of the housing 2 to be seen from the outside, a handle 5 that is gripped when the door 3 is opened and closed, and an operation display unit 6.

  The operation display unit 6 has a liquid crystal display 7, a time setting button group 8, a heating start button 9, a cancel button 10, and a pause button 11. As will be described later, the microwave oven 1 captures an image of a product that is an object to be heated (object to be heated) by the image capturing unit, reads the heating time displayed on the product, and heats the product at the heating time.

  The read heating time is displayed on the liquid crystal display 7. When the heating time is not read well, when the product for which the heating time is not displayed is heated, and when the user sets the heating time to his / her preference, the microwave oven 1 sets the time setting. A button group 8 is provided.

  The user can set the heating time using the numeric buttons and the "minute" and "second" buttons. In this case, the liquid crystal display 7 displays the set heating time.

  The heating start button 9 is a button that is pressed when the user starts heating after confirming the heating time displayed on the liquid crystal display 7. The cancel button 10 is pressed when the user presses the heating start button 9 to stop heating in the middle of heating after heating is started, or the heating time displayed on the liquid crystal display 7 is set. This button is pressed when canceling.

  The temporary stop button 11 is a button pressed by the user when the heating is temporarily stopped during heating. When the heating is temporarily stopped, the user can press the heating start button 9 again to perform the remaining heating from the middle. It should be noted that the cancel button 10 and the pause button 11 may be combined into one function and configured as one button.

  FIG. 2A is a diagram showing a schematic configuration of the microwave oven 1 according to the embodiment of the present disclosure.

  The microwave oven 1 is capable of heating food by high frequency, and is provided with a magnetron 13 which is a heating unit for outputting high frequency, on the outside of a heating chamber 12 that stores an object to be heated such as food and on the inside of a housing 2. ing. The microwave oven 1 supplies a high frequency to the heating chamber 12 to heat food. The magnetron 13 is controlled by the heating controller 14.

  The microwave oven 1 includes an illumination 15 and a camera 16 that is a photographing unit on the same side surface where the illumination 15 is provided. The camera 16, which is an imaging unit, captures an image in the heating cabinet 12.

  Since the camera 16 is arranged on the same side surface as the illumination 15, the inside of the heating chamber 12 can be photographed without being affected by the backlight. The camera 16 and the illumination 15 may be provided on the side surface, the upper surface, or the rear surface inside the heating chamber 12. Further, the lighting 15 and the camera 16 may be installed on different surfaces in the heating chamber 12 by using the lighting 15 as indirect lighting or the like.

  An example of specifications of the camera 16 in the present embodiment is as follows.

Horizontal pixel number t = 2592, vertical pixel number u = 1944
Focal length f = 2.3mm
Aperture value F = 2.4
Pixel size 1.12μm (0.00112mm) x 1.12μm
Horizontal viewing angle θh = 71.15 degrees, vertical viewing angle θp = 56.42 degrees The camera 16 has, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Device) image sensor, or the like. The inside of the heating chamber 12 is photographed.

  The housing 2 is provided with a door switch 17 for detecting opening / closing of the door 3. The door 3 is provided with a protrusion 18 for pushing in the door switch 17.

  FIG. 2B is a diagram showing a schematic configuration of the inner wall of the heating chamber 12 of the microwave oven 1 according to the embodiment of the present disclosure.

  FIG. 2B shows the inner wall of the heating chamber 12 excluding the door 3, and the front surface shows the front opening on the door 3 side. The inner wall of the heating chamber 12 has a substantially rectangular parallelepiped shape (including a rectangular parallelepiped), although it has some irregularities, and is defined by dimensions of width (d), depth (e), and height (f). In this embodiment, the width (d) is about 332 mm, the depth (e) is about 300 mm, and the height (f) is about 180 mm. Then, the longest straight line distance (g) in the refrigerator as a diagonal distance in the refrigerator is about 480 mm. Therefore, when the camera 16 is attached near the upper corner of the heating cabinet 12, the maximum distance from the camera 16 to the inner wall surface of the heating cabinet 12 is about 480 mm.

  FIG. 3 is a diagram showing an example of the seal 20 attached to the product in the embodiment of the present disclosure.

  The heating cabinet 12 stores items such as bento, rice balls, and prepared foods (objects to be heated). A sticker 20, which is a pasting product on which heating power and heating time, which is the heating control information 22 of the product, is attached to each of the products, mainly on the upper surface portion.

  As a guideline for heating with a general household microwave oven 1, for example, a heating time for heating with a heating power of 500 W, and a microwave oven 1 for commercial use As a guide for heating with a large heating power for a short time, for example, a heating time for heating with a heating power of 1500 W is also shown. Specifically, for example, a display such as "500W 2 minutes 00 seconds 1500W 0 minutes 40 seconds" is displayed.

  More specifically, the heating control information 22 includes a first character string that is a number indicating the amount of heating with a predetermined heating power, for example, "500", and a second character string that indicates the unit of the heating power, for example, " It is a character string that includes “W” and a third character string that is a number that is a heating time with the heating power, for example, “2” in this order. In addition, the heating control information 22 is, after the third character string, a fourth character string indicating the unit of the heating time, for example, “minute” and a fifth character string that is a number indicating the heating time at the heating power, For example, it is a character string including "00" and a sixth character string representing the unit of the heating time, for example, "second", in this order.

  In addition, the heating control information 22 includes, after the sixth character string, a seventh character string that is a number indicating the heating amount of the heating power larger than the predetermined heating power described above, for example, “1500” and the heating power of the heating power. It is a character string that includes an eighth character string indicating a unit, for example, "W", in this order. In addition, the heating control information 22 includes, after the eighth character string, a ninth character string that is a number that is a heating time with the heating power, for example, “0” and a tenth character string that represents a unit of the heating time, For example, “minutes”, an eleventh character string that is a number indicating the heating time with the heating power, for example, “40”, and a twelfth character string that indicates the unit of the heating time, for example, “seconds”, in this order. It is a character string containing.

  In the present embodiment, “W (Watt)”, which is the SI unit indicating the amount of heat, is used as the second character string and the eighth character string, but if it represents the unit of heating power, Other characters or units may be used. Further, as the fourth character string, the sixth character string, the tenth character string, and the twelfth character string, "minute" or "second" is used as a character representing the unit of time, but the unit of time is represented. Other characters or units may be used as long as they are.

  Returning to FIG. 2A, the reading unit 19 extracts, from the image captured by the camera 16, the location where the heating control information 22 attached to the product is displayed, and the characters of the heating control information 22 (at least the numbers are (Including characters).

  Therefore, the camera 16 may be provided on the side surface, the upper surface, or the rear surface of the heating chamber 12 as long as the reading unit 19 can read the heating control information 22. Usually, the height of the product to which the sticker 20 for displaying the heating control information 22 is attached is about 3 cm to about 9 cm. Therefore, the camera 16 may be installed at a position in the heating chamber 12 that is higher than the height.

  As shown in FIG. 3, the sticker 20 has a product name 21, heating control information 22, amount information 23, expiration date information 24, a bar code 25 which is an example of a code symbol for identifying a product, nutrition information 26, and , Various information such as notification information 27 is displayed. A leading mark 28 is displayed near the leading portion of the character string of the heating control information 22 on the sticker 20 so that the reading unit 19 can easily extract the heating control information 22 from such various information. There is. Note that, here, the character string of the heating control information 22 attached to the attached sticker 20 is supposed to be read, but the present disclosure is not limited to this. For example, the character string (heating control information 22 similar to that of the present embodiment) directly applied to the package of the product without the seal 20 may be photographed by the camera 16 and read by the reading unit 19.

  The reading unit 19 first extracts a head mark 28 having a special shape (a predetermined shape, here a star shape) from the image captured by the camera 16. Next, the reading unit 19 reads the alphanumeric characters following the head mark 28 as a character string “500W2001500W040”. Here, the reading unit 19 does not read a character representing a unit of time such as “minute” and “second”, or does not use it for analysis even if it is read.

  This is because, by using only alphanumeric characters for at least one of reading and analysis, it is possible to limit the number of characters to be read to a small number, so that the circuit, program, etc. can be made small, and This is because the shape of alphanumeric characters is simpler than that of Chinese characters, is easy to read, and can improve the recognizability.

  Then, the reading unit 19 converts the character string into a number string up to "W", a three-digit number string after "W", and a number up to "W" following the number string in accordance with a predetermined analysis rule. The sequence and the four columns of the 3-digit number sequence after the "W" are decomposed into "500", "200", "1500", and "040". Further, the reading unit 19 analyzes each of the second number string and the fourth number string, assuming that the first one digit is “minute” and the subsequent two digits are “second”.

  In the reading unit 19, the first number string is the heating power and corresponds to the time of the second number string, and the third number string is the heating power and the fourth number. Parse as corresponding to the time in the column. As a result, the heating control information 22 of "2 minutes at 500 W" and "40 seconds at 1500 W" is read.

  Returning to FIG. 2A, the user opens the door 3 and puts the product in the heating chamber 12. When the door switch 17 detects that the door 3 has been opened, the reading unit 19 reads the heating control information 22 from the image inside the heating chamber 12 taken by the camera 16 as described above.

  Here, the error determination unit 29 included in the reading unit 19 will be described.

  In the above-described example, the reading unit 19 has read the two types of heating control information 22 of “500 W for 2 minutes” and “1500 W for 40 seconds”. Here, the error determination unit 29 determines whether the relationship between the two heating control information 22 is correct.

  The total energy required to heat a food is a constant for that food. If the heating power is large, it will be heated in a short time, and if it is small, it will be heated in a long time. The heating power and the heating time have an almost inverse relationship. Therefore, when the reading unit 19 reads the two types of heating control information 22, the error determining unit 29 determines whether or not the relationship between them is substantially inversely proportional, and, for example, the inversely proportional relationship. If the difference is within 10% from, it is determined that the reading is correct. Details will be described later.

  When the reading unit 19 reads the heating control information 22 from the image taken by the camera 16, a reading error may occur. For example, the reading unit 19 may read numbers having similar shapes, such as “6” and “9”, and “0” and “8”, as different numbers. Further, when the reading unit 19 misreads the leading mark 28, other numbers such as the amount information 23 and the expiration date information 24 are displayed on the sticker 20 as shown in FIG. However, they may be erroneously read as the numbers of the heating control information 22.

  If the heating control is performed with the number read by mistake, it may result in overheating or insufficient heating. In order to prevent this, the error determination unit 29 determines the reading error of the reading unit 19.

  Returning to FIG. 2A, if the error determination unit 29 determines that the relationship between the two types of heating control information 22 is correct, the reading unit 19 sends the two types of heating control information 22 to the heating control unit 14. The heating control unit 14 selects one of the two types of heating control information 22, specifically, the heating control information 22 having a larger heating power within the range of heating power that can be heated by the microwave oven 1. , To the operation display unit 6. The operation display unit 6 displays the heating time of the selected heating control information 22 on the liquid crystal display 7.

  The user confirms that the appropriate heating time is displayed on the liquid crystal display 7, closes the door 3, and presses the heating start button 9. When the heating control unit 14 receives a signal indicating that the door is closed from the door switch 17 and a signal indicating that the heating start button 9 has been pressed from the operation display unit 6, the heating control unit 14 determines as described above. The magnetron 13 is heated and controlled so that the product is heated with the heating power and the heating time of the selected heating control information 22.

  Here, the microwave oven 1 of the present embodiment has been described as using the leading mark 28 when reading the heating control information 22 from the sticker 20. However, the present disclosure is not limited to this example, and by using the position designation mark 128 having a predetermined shape and having a predetermined positional relationship with the heating control information 22, the heating control information 22 can be read with high accuracy.

  FIG. 4 is a diagram showing an example of the position designation mark 128 displayed on the sticker 20 according to the embodiment of the present disclosure.

  In the example of FIG. 4, a rectangular position designation mark 128 formed so as to surround the heating control information 22 is shown. The reading unit 19 extracts the position designation mark 128 and reads the heating control information 22 written therein. It should be noted that the position designation mark 128 is not limited to a rectangular shape, and may have any shape. Further, the positional relationship between the heating control information 22 and the position designation mark 128 is not limited to the example shown in FIG. 4 and may be any positional relationship.

  FIG. 5A is a plan view showing a state where the bottom surface in the heating cabinet 12 is viewed from above in the embodiment of the present disclosure, and FIG. 5B is a plan view showing the bottom surface in the heating cabinet 12 when viewed from above. FIG. 5C is a plan view showing a placed state, and FIG. 5C is another plan view showing a state in which the bottom surface of the heating chamber 12 is viewed from above.

  As shown in FIG. 5A, at least one of a marker with characters such as “Please put food in the center” and / or a bracket (“”) type marker on the bottom of the heating chamber 12. Granted. As a result, as shown in FIG. 5B, the user can remind the user of the place where the product (food to be cooked) to which the seal 20 is attached should be placed. In this way, when the user places the object to be heated in the heating chamber 12 of the heating cooker, the user can be guided so as to place the object to be heated in a place where the reading unit 19 can easily read it. As a result, in the heating chamber 12 of the heating cooker, the characters attached to the object to be heated are separated from the camera 16, and the characters of the heating control information 22 applied to the object to be heated are read. It is possible to minimize the possibility of not being recognized by. Therefore, it is possible to reduce the possibility that the heating cannot be started because the characters of the heating control information 22 are not recognized. In addition, the user can minimize the troublesome work such as opening the door 3 of the heating cooker and changing the placement position of the object to be heated.

  Further, as shown in FIG. 5C, at least one of the shape and the wording of the marker is changed (here, the shape is a substantially rectangular shape, and the wording is “put the product in this range”). ), Or the position of the marker may be shifted according to the position of the camera 16 (for example, when the camera 16 is installed at an upper position corresponding to the lower left corner side where the marker is provided). Place markers as in FIG. 5C).

  The distance from the camera 16 to the character of the heating control information 22 provided on the sticker 20 is about 480 mm or less, which is the longest distance from the camera 16 to the inner wall surface of the heating chamber 12.

  FIG. 6 is a diagram showing an example of the inner wall of the heating chamber 12 of the microwave oven 1 when the camera 16 is installed on the upper surface of the heating chamber 12 substantially at the center.

  Markers for instructing the placing of food should be displayed so that the seal 20 can be placed in the areas spaced 20 mm from the front, rear, left and right walls. As described above, since the height of the food is approximately 30 to 90 mm, the distance from the camera 16 to the four corners farthest from the camera 16 is 30 mm, which is the height of the shortest food. , About 250 mm.

  Next, a method for surely reading a character at a distance of 250 mm or less will be described. In addition, here, the camera 16 is installed on the upper surface of the heating chamber 12 substantially at the center, but the position of the camera 16 may be toward the front of the heating chamber 12 or toward the rear thereof. I shall. Here, the specifications of the camera 16 and the depth of field will be described again. An example of specifications of the camera 16 in the present embodiment is as follows.

Horizontal pixel number t = 2592, vertical pixel number u = 1944
Focal length f = 2.3mm
Aperture value F = 2.4
Pixel size 1.12μm (0.00112mm) x 1.12μm
Horizontal viewing angle θh = 71.15 degrees, vertical viewing angle θp = 56.42 degrees Center of distance to subject to be focused d ₀ = 200 mm
In this specification, the front depth of field D _n is generally expressed by the following equation. Here, the permissible circle of confusion circle c is the pixel size.

The rear depth of field D _f is generally expressed by the following equation.

Therefore, the front depth of field D _{n in} front of the subject is 18.45 mm, and the rear depth of field D _{f in} the rear of the subject is 22.62 mm. That is, from the center of the distance to the subject to be focused from 200 mm to 181.55 mm before 18.45 mm, the focus is also from 22.62 mm behind the center to 222.62 mm. become. The generally known depth of field is 18.45 mm + 22.62 mm = 41.07 mm.

  If the distance from the camera 16 to the subject is in the range of 181.55 to 222.62 mm, the subject is in focus. If it deviates from this range, the focus will shift. The further it deviates from the above range, the larger the focus shift. If the image is out of focus, the image will be out of focus. The index of the degree of blurring of this image is the circle of confusion (c).

Generally, the diameter of the circle of confusion (c) is expressed by the following equation when the distance from the camera to the subject is d _n (d ₀ > d _n ). In the present disclosure, the distance from the camera (imaging unit) to the subject is the distance from the center point of the optical system of the camera in the optical axis direction to the subject.

When d _n (d ₀ <d _n ), (d ₀ −d _n ) of the numerator is changed to (d _n −d ₀ ). Therefore, the ratio r between the diameter of the circle of confusion and the diameter of the circle of confusion is temporarily defined as the degree of blur.

  Then, the permissible circle of confusion diameter is defined as the pixel size (x), and the ratio b = x / c is defined as the blur degree. Then, when the value of the blur degree b = x / c exceeds 1, the value of the blur degree b is fixed to “1”. In this case, the maximum value of the blurring degree b becomes 1, and the larger the circle of confusion, that is, the larger the blurring degree, the smaller the blurring degree b becomes. Then, the range of c ≦ x is the range of the depth of field, and since the range is in focus, the blur degree may be set to the maximum value b = 1.

The specifications of the camera 16 are as follows: focal length f = 2.3 mm, aperture value F = 2.4, pixel size 1.12 μm (0.00112 mm) × 1.12 μm, center of distance to object to be focused d ₀ = 200 mm. FIG. 7 shows the relationship between the distance from the camera 16 to the subject and the blur degree b = x / c at this time. It has been shown that the degree of blurring in the range of the depth of field including the center of focus is the maximum value of 1, and the further away from it, the lower the degree of blurring, that is, a blurred image. .

  Next, the resolution taken by the camera 16 will be described. The object appears smaller as the distance from the camera 16 increases, and the object becomes larger as the distance from the camera 16 increases. That is, the farther the distance from the camera 16 to the subject, the lower the resolution, and the closer the distance, the higher the resolution. When the distance from the camera 16 to the subject is d, the length occupied by one pixel can be represented by a trigonometric function of 2 × tan (θ / (n / 2)). Here, θ is the viewing angle, and n is the number of pixels. And, generally speaking, the resolution is the reciprocal thereof.

  As the specifications of the camera 16, the horizontal pixel number t = 2592, the vertical pixel number u = 1944, the horizontal viewing angle θh = 71.15 degrees, the vertical viewing angle θp = 56.42 degrees, the horizontal resolution (h), the vertical FIG. 8 shows the relationship between the resolution (p) and the distance, with the resolution being the unit of dpi. The larger this value, the easier the reading, and the smaller this value, the more difficult the reading.

Here, the resolution required to properly read a character will be described. When the characters to be read are limited to alphanumeric characters, there are fonts printed with a minimum of 8 dots x 8 dots. That is, if there are 8 dots × 8 dots, it is possible to display with alphanumeric distinction. On the other hand, in general, to read it, twice the resolution is required, and if there is a resolution of 16 dots × 16 dots for one character, it can be distinguished. If the character size is 10 points, which is a relatively small size among commonly used sizes, the vertical length is 0.14 inch. Therefore, the required vertical resolution is the recognition reference resolution r = 115 dpi determined by the recognized character size. The character has a size, and similarly in the horizontal direction, if the recognition reference resolution r = 115 dpi, then in terms of area, r ² = 115 × 115 dpi ² .

If the product of the horizontal resolution (h) and the vertical resolution (p) shown in FIG. 8 is larger than the recognition resolution r ² , it can be read, but a blur factor must be added to it. I have to. When the blurring occurs, the substantial resolution is lowered. Therefore, the product of the horizontal resolution (h) and the vertical resolution (p) shown in FIG. 8 is multiplied by the blurring degree shown in FIG. However, it is the actual resolution. This substantial resolution is shown in FIG. 9 as the recognition resolution q ² .

In the range where the recognition resolution q ² exceeds the recognition reference resolution r ² , it means that characters can be read, and even if the character is out of focus, the distance is closer (the distance is longer than the range in focus). , The characters can be read. In the microwave oven 1, assuming that the maximum distance from the camera 16 to the character is 250 mm and the focus is set to 200 mm, the distance to the character exceeds the in-focus range when judged from the depth of field. However, in the case of a long distance (when the distance is farther than the in-focus range), the extent of exceeding the in-focus range is smaller than in the short-distance range, and , The recognition resolution q ² exceeds the recognition reference resolution r ² in all ranges in the range of a distance shorter than 250 mm because the resolution increases even if the degree of exceeding the in-focus range is large. Therefore, if the seal 20 is placed in the designated area, the character can be read with high accuracy.

  Further, it is desirable that the inside of the heating chamber 12 has a width of 350 mm or less, a depth of 320 mm or less, and a height of 200 mm or less.

  With such a configuration, the character attached to the product (object to be heated) and the camera 16 in the heating chamber 12 of the heating cooker are separated from the camera 16, and the heating control information 22 applied to the object to be heated 22. It is possible to minimize the possibility that the character "" will not be recognized by the reading unit. Therefore, since the characters of the heating control information 22 are not recognized, it is less likely that heating cannot be started. In addition, the user can minimize the troublesome work such as opening the door 3 of the heating cooker and changing the placement position of the object to be heated.

  With this configuration, the distance between the camera 16 and the characters attached to the object to be heated is set to be shorter than the predetermined distance from the camera 16 in the relatively narrow space inside the heating chamber 12 of the heating cooker. In the range of the distance to the character given to the object to be heated, no matter where the object to be heated is placed in the specified range, the accuracy of reading the character including the heating control information 22 and the like is maximized. be able to.

  Further, even when the character provided on the object to be heated and the camera 16 are considerably close to each other, the accuracy of reading the character including the heating control information 22 and the like can be increased as much as possible. In the present disclosure, “substantially close” means a distance of about 90 mm in consideration of the height of a food or the like as a subject.

In the above description, the range in which the recognition resolution q ² is the recognition reference resolution r ² or more is the readable range, but the distance between the camera 16 and the character that needs to be read and includes the heating control information 22 and the like. If is too close, the character 16 may not fit within the field of view due to the length of the character.

  Therefore, it is desirable that the distance from the camera 16 to the character of the heating control information 22 is 90 mm or more. If the length of the character that needs to be read and that includes the heating control information 22 is within 50 mm, the reading accuracy of the character that includes the heating control information 22 and the like can be increased as much as possible.

  Furthermore, if the viewing angle of the camera 16 is 31 degrees or more, even if the distance from the camera 16 to the characters of the heating control information 22 is considerably short, the heating control information 22 and the like are included and need to be read. If the length of the character is within 50 mm, the reading accuracy of the character including the heating control information 22 and the like can be increased as much as possible.

  Next, operation steps of the microwave oven 1 of the present embodiment will be described.

  FIG. 10 is a flowchart showing the operation flow of the heating control unit 14, the reading unit 19, and the error determination unit 29 in the embodiment of the present disclosure.

  Here, at least some of the functions of the heating control unit 14, the reading unit 19, and the error determination unit 29 may be realized by a microcomputer and peripheral circuits, as an example.

  The microcomputer and peripheral circuits may take any form as long as they perform the control described later. The heating control unit 14, the reading unit 19, and the error determination unit 29 may be configured by an arithmetic processing unit and a storage unit that stores a control program. Examples of the arithmetic processing unit include an MPU (Micro Processing Unit) and a CPU (Central Processing Unit). A memory is exemplified as the storage unit. The control program recorded in the storage unit is executed by the arithmetic processing unit.

  The heating control unit 14, the reading unit 19, and the error determining unit 29 may be configured by hard logic. If configured with hard logic, it is effective in improving the processing speed. Each component may be composed of one semiconductor chip or may be physically composed of a plurality of semiconductor chips. When the heating control unit 14, the reading unit 19, and the error determination unit 29 are composed of a plurality of semiconductor chips, each control described later can be realized by a different semiconductor chip.

  First, the reading unit 19 determines whether or not the door 3 is open depending on the state of the door switch 17 (S1). If the door 3 is open (S1, YES), the process proceeds to step S2. On the other hand, if the door 3 is closed (S1, NO), the reading unit 19 repeats step S1 and waits for the door 3 to open.

  The reading unit 19 takes an image of the bottom surface of the heating chamber 12 with the camera 16 (S2), and proceeds to step S3.

  The reading unit 19 searches for the leading mark 28 or the position designation mark 128 in the image (S3). When the leading mark 28 or the position designation mark 128 is found (S3, YES), the reading unit 19 proceeds to step S4. On the other hand, if the head mark 28 or the position designation mark 128 is not found (S3, NO), the reading unit 19 proceeds to step S12.

  In step S4, the reading unit 19 reads an alphanumeric character based on the head mark 28 or the position designation mark 128, and reads the character string "500W2001500W040" in the example of the sticker 20 shown in FIG. . Then, according to a predetermined analysis rule, the character string is analyzed as two kinds of heating control information 22 of “500 W for 2 minutes” and “1500 W for 40 seconds”.

  Next, in step S5, the error determination unit 29 determines whether or not the heating control information 22 read by the reading unit 19 has been correctly read. Specifically, the error determining unit 29 determines that the second heating control information “1500 W for 40 seconds” is within ± 10% with respect to the first heating control information “500 W for 2 minutes”. Determine if there is an inverse relationship in the range.

  The error determination will be described more specifically. In the above example, the heating power of the first heating control information is “500 W”, while the heating power of the second heating control information is “1500 W”, which is triple. Therefore, the error determination unit 29 determines that the heating time of the first heating control information is “2 minutes”, and therefore the heating time of the second heating control information is within ± 10% of “40 seconds” which is one-third of the heating time. That is, if it is 36 seconds to 44 seconds, it is determined that the correct reading is completed.

  In step S6, it is determined whether or not there is an error in reading based on the determination result in step S5. If there is no error in the read result (S6, NO), the process proceeds to step S7. On the other hand, if there is an error (S6, YES), the process proceeds to step S12.

  In step S7, the reading unit 19 sends two types of heating control information 22 of "500 W for 2 minutes" and "1500 W for 40 seconds" to the heating control unit 14. If the heating controller 14 can control the magnetron 13 at a maximum of 1500 W, the heating time corresponding to the heating power of "1500 W" is displayed on the liquid crystal display 7 as "40 seconds", for example. .

  In step S8, the reading unit 19 determines the state of the door switch 17 to determine whether the door 3 is closed. If it is determined that the door 3 is closed (S8, YES), it is determined that the reading is confirmed, and the process proceeds to step S9. On the other hand, if it is determined that the door 3 is not closed (S8, NO), it is determined that the reading is in an undetermined state, the process returns to step S2, and the processes from step S2 to step S8 are repeated.

  In step S9, the heating control unit 14 determines whether or not the cancel button 10 has been pressed by the user. If the cancel button 10 is not pressed (S9, NO), the process proceeds to step S10. On the other hand, when the cancel button 10 is pressed (S9, YES), the process proceeds to step S13. This is because when the user confirms the heating time displayed on the liquid crystal display 7 and determines that the heating time is wrong, or when the user wants to heat at another heating time, the cancel button 10 is pressed. This is for detecting that the heating has occurred and heating for a heating time other than the read heating time.

  In step S10, the heating control unit 14 determines whether or not the heating start button 9 is pressed. If the heating start button 9 is pressed (S10, YES), the process proceeds to step S11 to start heating (S11). On the other hand, if the heating start button 9 has not been pressed (S10, NO), the process returns to step S9 to repeat the determination process as to whether the cancel button 10 has been pressed.

  If the leading mark 28 or the position designation mark 128 is not found in step S3 (S3, NO), and if it is determined in step S6 that the read character string has an error (S6, YES), In step S12, the reading unit 19 uses the door switch 17 to determine whether the door 3 has been closed. If the door 3 is closed (S12, YES), the process proceeds to step S13. On the other hand, if the door 3 is not closed (S12, NO), the process returns to step S2, and each process is repeated from the photographing by the camera 16.

  Normally, the above-described loop of returning from step S12 to step S2 is repeated from the time the user opens the door 3 until the food is put in the heating chamber 12 and kept stationary.

  Then, if the cancel button 10 is pressed in step S9 (S9, YES) and if the door 3 is closed in step S12 (S12, YES), the process proceeds to step S13. In step S13, the heating control unit 14 receives the heating time manually set by the user. This is because when the food for which the heating control information 22 is not displayed is heated, or when the reader 19 cannot read the heating control information 22 due to dirt or the like, the user sets the heating time to the time. This is because the setting button group 8 can be used for manual setting.

  Then, in step S14, the heating control unit 14 determines whether or not the heating start button 9 is pressed. If the heating start button 9 is pressed (S14, YES), the process proceeds to step S11 to start heating. On the other hand, if the heating start button 9 has not been pressed (S14, NO), the process returns to step S13, and the process in which the heating control unit 14 receives the user's manual setting operation is repeated.

  As described above, according to the present embodiment, the reading unit 19 reads the characters (characters including at least alphanumeric characters) of the heating control information 22 displayed on the product, and based on the heating control information 22, the heating control is performed. The unit 14 controls the magnetron 13. Thereby, the clerk can automatically set the heating time without inputting the heating time of the product or selecting the button corresponding to the product. Further, it is possible to eliminate the troublesome work of registering the relationship between the product code and the heating time.

  Further, the error determination unit 29 determines an error in reading based on whether or not the relationship between the heating power and the heating time is correct from the information on the heating time at each of the two heating powers of “500 W” and “1500 W”. As a result, it is possible to properly heat without causing erroneous heating due to erroneous reading.

  Further, the reading unit 19 detects the open / closed state of the door 3 with the door switch 17, starts reading by photographing with the camera 16 when the door 3 is opened, and finalizes the read content when the door 3 is closed. . Thereby, when the heating control information 22 cannot be read well with the door 3 opened, the user can change the place or the direction of the product, and make the condition easy to read.

  In addition, in this Embodiment, the reading part 19 demonstrated as what reads the heating control information 22 from the character string given to the goods. However, the present disclosure is not limited to this example. For example, in at least one of the mode related to the operation of the error determination unit 29 and the mode related to the open / closed state of the door 3 and the start and end of the operation of the reading unit 19, the reading unit 19 determines that the information given to the product. The heating control information 22 may be read from a bar code or a two-dimensional code that is a code.

  As described above, according to the present disclosure, in the heating chamber of the heating cooker, the characters of the object to be cooked and the characters of the heating control information applied to the object to be heated are separated from the imaging unit. It is possible to minimize the possibility that the reading unit cannot recognize. Therefore, it is possible to reduce the possibility that heating cannot be started without recognizing the characters of the heating control information, and the user opens the door of the heating cooker and changes the placement position of the object to be heated, which is troublesome. Work can be reduced as much as possible. Therefore, the present disclosure can be applied to and is useful in general microwave ovens used in stores, household microwave ovens, rice cookers, and general cookers such as IH cooking heaters.

1 microwave oven 2 housing 3 door 4 glass window 5 handle 6 operation display section 7 liquid crystal display 8 time setting button group 9 heating start button 10 cancel button 11 pause button 12 heating chamber 13 magnetron (heating section)
14 heating control unit 15 lighting 16 camera (imaging unit)
17 Door Switch 18 Protrusion 19 Reading Part 20 Seal 21 Product Name 22 Heating Control Information 23 Price Information 24 Expiration Date Information 25 Bar Code (Code Symbol)
26 Nutrition Information 27 Information Information 28 Start Mark 29 Error Judgment Section 128 Position Designation Mark

Claims (6)

A heating cabinet in which the object to be heated is stored,
A heating unit that heats the object to be heated stored in the heating chamber,
A photographing unit for photographing the inside of the heating chamber,
A reading unit for reading the characters of the heating control information given to the object to be heated,
A heating control unit that controls the heating unit based on the heating control information read by the reading unit;
The distance from the imaging unit to the character of the heating control information is 480 mm or less,
Heating cooker. The heating chamber has a marker for designating a place where the object to be heated is placed at a place where a distance from the photographing unit to the character of the heating control information is 480 mm or less.
The heating cooker according to claim 1. The inside of the heating chamber has a width of 350 mm or less, a depth of 320 mm or less, and a height of 200 mm or less.
The heating cooker according to claim 1 or 2. In the image capturing unit, when the distance from the image capturing unit to the character of the heating control information is 250 mm or less,
The recognition reference resolution determined by the size of the character is (r),
When the horizontal resolution (h), the vertical resolution (p), the circle of confusion (c), and the pixel size (x) of the image captured by the image capturing unit are set, the following relationship holds (x / c) × (H × p)> r ²
The heating cooker according to any one of claims 1 to 3, which is configured as described above. The distance from the imaging unit to the character of the heating control information is 90 mm or more,
The heating cooker according to any one of claims 1 to 4. The viewing angle of the photographing unit is 31 degrees or more,
The heating cooker according to any one of claims 1 to 5.

Images