Analog meter reading device, reading method, and reading program

Abstract

To provide a reading apparatus, a reading method and a reading program of an analog meter which can easily read an analog meter.SOLUTION: An analog meter comprises: a circular scale; and an indication needle which indicates an indicated value on the scale by rotating around a predetermined rotation center. A reading apparatus of the analog meter comprises: a storage device which stores an image obtained by imaging the analog meter; and a control device which executes processing for reading the indicated value from the image of the analog meter stored in the storage device. The control device extracts the indication needle from the image of the analog meter by performing pattern matching with a diagram for each of a plurality of portions having different shapes of the indication needle (step S103). The control device calculates the indicated value on the basis of an angle formed by the extracted indication needle and a predetermined reference line (step S104).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an apparatus, a method and a program for reading an analog meter. [Background technology]

[0002] Conventionally, for example, various types of analog meters are installed in a factory. An operator visually checks the analog meters and manually registers the checked analog meter values ​​in a database. However, when there are many analog meters, or when the analog meters need to be read in turn, it is cumbersome to visually read each analog meter one by one.

[0003] Therefore, devices that automatically read analog meter values ​​have been proposed in the past. For example, the reading system in Patent Document 1 compares an image of an analog meter uploaded from a mobile information terminal with a classification model (learning model) created in advance to determine the measurement position of the pointer of the analog meter and read the measured value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-181467 A Summary of the Invention [Problem to be solved by the invention]

[0005] The reading system of Patent Document 1 certainly can read analog meters automatically. However, the reading system of Patent Document 1 requires that image data for learning be prepared for each type of analog meter, and that a learning model be created for each type of analog meter using the prepared image data. This is troublesome. [Means for solving the problem]

[0006] An analog meter reading device that can solve the above problem is an analog meter reading device having an arc-shaped scale and an indicator needle that rotates around a determined center of rotation to indicate a value on the scale. The analog meter reading device includes a storage device that stores an image of the analog meter, and a control device that executes a process for reading the indicated value from the image of the analog meter stored in the storage device. The control device extracts the indicator needle from the image of the analog meter by performing pattern matching using graphics for each of a plurality of parts of the indicator needle that have different shapes, and calculates the indicated value based on the angle between the extracted indicator needle and a determined reference line.

[0007] According to this configuration, unlike a type of device that reads the analog meter reading by comparing an image of the analog meter with a pre-created learning model, there is no need to create a learning model, so the analog meter can be read easily.

[0008] In the analog meter reading device described above, the indicator needle may include portions having at least two of a rectangular shape, a circular shape, and a triangular shape when viewed from the front.

[0009] According to this configuration, the indicator needle can be extracted from the image of the analog meter by performing pattern matching using graphics for each portion of the indicator needle that has at least two of the following shapes: a square shape, a circle shape, and a triangle shape.

[0010] In the above-mentioned analog meter reading device, the control device may approximate the indicator needle extracted from the image of the analog meter into a rectangle, set a center line extending along the longitudinal direction of the rectangularly approximated indicator needle for the image of the analog meter, and calculate the indication value based on the angle between the set center line and the reference line.

[0011] According to this configuration, it is possible to calculate the indicated value based on the angle between the center line of the indicator needle approximated to a rectangular shape and the reference line. In the analog meter reading device, the indicator needle may have an area that narrows from the end to the tip when viewed from the front, in which case the control device may recognize the direction in which the area of ​​the indicator needle extracted from the image of the analog meter narrows as the direction indicated by the indicator needle, and may calculate the indicated value based on an angle between a portion of the center line corresponding to the tip and the reference line.

[0012] According to this configuration, it is possible to calculate a more accurate indication value based on the angle formed between the reference line and the portion of the center line corresponding to the tip of the indicator needle. In the analog meter reading device, the storage device may store table data defining a relationship between the angle and the indicated value, and in this case, the control device may calculate the indicated value using the table data based on the angle.

[0013] According to this configuration, by using the table data, the indication value can be calculated more easily. In the analog meter reading device described above, the control device may be adapted to horizontally correct the inclination of the image of the analog meter prior to the process of extracting the image of the indicator needle.

[0014] According to this configuration, by correcting the inclination of the image of the analog meter to be horizontal, it is possible to calculate a more accurate indicated value. In the above-mentioned analog meter reading device, the control device may extract the analog meter from the image of the analog meter, approximate the extracted analog meter to an ellipse, and rotate the image of the analog meter so that the major axis of the ellipse is horizontal.

[0015] According to this configuration, by rotating the image of the analog meter so that the major axis of the analog meter that approximates an ellipse is horizontal, the inclination of the image of the analog meter can be corrected to be horizontal.

[0016] In the above-mentioned analog meter reading device, when the image of the analog meter includes an object that should be arranged horizontally or vertically, the control device may rotate the image of the analog meter so that the object is horizontal or vertical.

[0017] According to this configuration, the image of the analog meter can be rotated so that an object that should be placed horizontally or vertically becomes horizontal or vertical, thereby correcting the inclination of the image of the analog meter to be horizontal.

[0018] In the analog meter reading device, the scale may be symmetrical about a line connecting the midpoint of the arc and the center point of the arc, and may have a start point corresponding to a minimum value of the scale and an end point corresponding to a maximum value of the scale. In this case, the control device may set a reference line that is a straight line connecting the start point and the end point on the image of the analog meter, and rotate the image of the analog meter so that the set reference line is horizontal.

[0019] According to this configuration, the image of the analog meter can be rotated so that the reference line, which is the straight line connecting the start point and end point of the scale, is horizontal, thereby making it possible to correct the inclination of the image of the analog meter to be horizontal.

[0020] In the above-mentioned analog meter reading device, prior to the process of extracting an image of the indicator needle, the control device may extract the analog meter from the image of the analog meter, approximate the extracted analog meter to an ellipse, and correct the image of the analog meter so as to make the approximated ellipse closer to a circle.

[0021] According to this configuration, by approximating the analog meter to an ellipse and then correcting the image of the analog meter so that the approximated ellipse approaches a circle, the scale of the analog meter becomes equally spaced as when viewed from the front, making it possible to calculate a more accurate indicated value.

[0022] In the above analog meter reading device, the image of the analog meter stored in the storage device may include an image of the analog meter sent via a network from a mobile terminal carried by a person who photographed the analog meter.

[0023] With this configuration, all that is required is to take a picture of the analog meter to be read with a mobile terminal and send the image of the analog meter to the reading device. The analog meter data sent from the mobile terminal is automatically read by the reading device. This is convenient because the worker does not need to visually read the analog meter.

[0024] A method for reading an analog meter that can solve the above problem is a method for reading an analog meter having an arc-shaped scale and an indicator needle that rotates about a determined center of rotation to indicate a value on the scale, the method for reading an analog meter comprising the steps of: extracting the indicator needle from an image of the analog meter stored in a storage device by performing pattern matching using graphics for each of a plurality of parts of the indicator needle that have different shapes; and calculating the indicated value based on the angle between the indicator needle extracted from the image of the analog meter and a determined reference line.

[0025] According to this reading method, unlike a method of reading the indicated value of an analog meter by comparing an image of the analog meter with a learning model created in advance, there is no need to create a learning model, so the analog meter can be read easily.

[0026] The analog meter reading program capable of solving the above problem is an analog meter reading program that causes a computer to execute a process for reading an indicated value from an image of an analog meter having an arc-shaped scale and an indicator needle that rotates about a determined center of rotation to indicate the indicated value on the scale. The analog meter reading program has the steps of: extracting the indicator needle from the image of the analog meter by performing pattern matching using graphics for each of a plurality of parts of the indicator needle that have different shapes; and calculating the indicated value based on the angle between the indicator needle extracted from the image of the analog meter and a determined reference line.

[0027] Unlike a program that reads the analog meter reading by comparing an image of the analog meter with a pre-created learning model, this reading program does not require the creation of a learning model, making it possible to easily read an analog meter. Effect of the Invention

[0028] According to the present invention, an analog meter can be easily read. [Brief description of the drawings]

[0029] [Figure 1] 1 is a block diagram showing a state in which an embodiment of an analog meter reading device and a mobile terminal are connected via a network. [Diagram 2] 1 is a block diagram showing a configuration of an embodiment of a reading device and a portable terminal connected via a network. [Diagram 3] FIG. 1 is a block diagram showing a configuration of an embodiment of a reading device. [Figure 4] 4 is a flowchart showing a reading process procedure of an analog meter in one embodiment. [Diagram 5] 13A, 13B, and 13C are front views for explaining the extraction process of a meter according to an embodiment. [Figure 6]5A, 5B, and 5C are front views for explaining a correction process for a meter image in one embodiment. [Figure 7] 13A and 13B are front views for explaining the extraction process of the indicator needle in one embodiment. [Figure 8] 1A, 1B, and 1C are front views for explaining a reading process of an indicator needle in one embodiment. [Figure 9] 13(a) and 13(b) are front views showing the interpolation process of an indicator needle in one embodiment. [Figure 10] 13(a) and 13(b) are front views showing the interpolation process of a dial according to an embodiment. [Figure 11] 13(a), (b), and (c) are front views for explaining a correction process for a meter image in another embodiment. [Figure 12] 13(a) and 13(b) are front views for explaining a correction process for a meter image in another embodiment. [Figure 13] 13(a) and 13(b) are front views for explaining a correction process for a meter image in another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment of an analog meter reading device, a reading method, and a reading program will be described. As shown in FIG. 1, the reading device 10 is connected to a communication network 20 such as the Internet. The reading device 10 is provided in a business such as an electric power company. The reading device 10 can communicate with a mobile terminal 30 via the communication network 20. The mobile terminal 30 includes a so-called tablet terminal or a smartphone. The mobile terminal 30 is used to photograph an analog meter 40 installed in a factory or the like. The analog meter 40 indicates an indicated value by a scale 40A (dial) and an indicator needle 40B. The mobile terminal 30 transmits a meter image, which is an image of the photographed analog meter 40, to the reading device 10. The reading device 10 receives the meter image transmitted from the mobile terminal 30. The reading device 10 reads the indicated value of the analog meter from the meter image and registers the read indicated value in a database.

[0031] 2, the mobile terminal 30 includes a storage device 30A, a communication device 30B, a control device 30C, a display 30D, and a camera 30E. The storage device 30A, the communication device 30B, the control device 30C, the display 30D, and the camera 30E are connected to each other via a bus 30F, which is a signal line.

[0032] The camera 30E is capable of capturing moving images and still images. The camera 30E captures an image of a subject in accordance with a command from the control device 30C. The subject includes the analog meter 40. The display 30D is, for example, a touch panel, and it is possible to input data or instruct the mobile terminal 30 to operate by touching what is displayed on the screen of the display 30D.

[0033] The storage device 30A stores information according to commands from the control device 30C. The information includes image data, which is data of an image captured by the camera 30E. The storage device 30A has a RAM (Random Access Memory) and a ROM (Read Only Memory). The RAM is a working area when the control device 30C performs processing, and temporary data such as computer programs or calculation results are deployed in the RAM. The ROM stores the computer programs and data executed by the control device 30C.

[0034] The communication device 30B is an interface between the control device 30C and the communication network 20. The communication device 30B transmits and receives information via the communication network 20. The communication device 30B transmits and receives information to and from external devices connected to the communication network 20 in accordance with commands from the control device 30C. The external devices include the reading device 10.

[0035] The control device 30C has a processor such as a CPU (Central Processing Unit). The processor centrally controls the entire mobile terminal 30 through the execution of a computer program deployed in a working area of ​​the storage device 30A. The control device 30C controls the operation of the camera 30E in accordance with a user's operation. The control device 30C stores image data captured by the camera 30E in the storage device 30A. The control device 30C may add unique identification information and a capture date and time to the image data of the analog meter 40.

[0036] 3, the reading device 10 includes a storage device 10A, a communication device 10B, a control device 10C, a display 10D, and an input device 10E. The storage device 10A, the communication device 10B, the control device 10C, the display 10D, and the input device 10E are connected to each other via a bus 10F, which is a signal line.

[0037] Display 10D is, for example, a liquid crystal display or an organic electroluminescent display. The input device 10E includes a keyboard, a mouse, etc. Various functions of the reading device 10 are executed and various data are input through the input device 10E.

[0038] The communication device 10B is an interface between the control device 10C and the communication network 20. The communication device 10B transmits and receives information via the communication network 20. The communication device 10B transmits and receives information to and from external devices connected to the communication network 20 in accordance with commands from the control device 10C. The external devices include a mobile terminal 30.

[0039] The storage device 10A has, for example, a main memory unit 10A3 and an auxiliary memory unit 10A4. The main memory unit 10A3 stores computer programs executed by the control device 10C, data processed by the control device 10C, and the like. The programs include a reading program 10A1 for the analog meter 40. The reading program 10A1 is a computer program that executes a process for reading the indicated value of the analog meter 40 from an image of the analog meter 40. The reading program 10A1 includes various image processing programs. The main memory unit 10A3 has a RAM (Random Access Memory) and a (Read Only Memory).

[0040] The auxiliary storage unit 10A4 is a non-volatile storage device that stores various programs including an OS (Operating System) and various data in a readable and writable manner. The auxiliary storage unit 10A4 is a flash memory, a hard disk drive, a solid state drive (SSD), or the like. The OS includes a communication interface program that transfers data between the OS and an external device connected via the communication device 10B. The auxiliary storage unit 10A4 stores information received via the communication device 10B. This information includes image data of the analog meter 40 sent from the mobile terminal 30 via the communication network 20.

[0041] The control device 10C executes various processes according to the programs stored in the storage device 10A. The control device 10CA has a processor such as a CPU (Central Processing Unit). The processor centrally controls the entire reading device 10 through the execution of the computer programs deployed in the working area of ​​the storage device 10A.

[0042] The control device 10C receives image data of the analog meter 40 sent from the mobile terminal 30 via the communication network 20 via the communication device 10B, and stores the received image data in the storage device 10A in a state in which the image data is associated with identification information unique to the analog meter 40. The control device 10C is capable of displaying an image of the analog meter 40 on the display 10D based on the image data of the analog meter 40 stored in the storage device 10A. The control device 10C automatically reads the indicated value of the analog meter 40 based on the image data of the analog meter 40 stored in the storage device 10A.

[0043] <Procedure for reading analog meter 40> Next, the procedure for reading the analog meter 40 will be described. 4, the reading process of the analog meter 40 includes four processes, steps S101 to S104. These four processes, steps S101 to S104, are executed according to a reading program 10A1 for the analog meter 40 stored in the storage device 10A.

[0044] <Step S101> First, the control device 10C extracts an image of the analog meter 40 from the images stored in the storage device 10A (step S101).

[0045] As shown in Fig. 5(a), an example image 50 is an image of a meter panel 51 on which a plurality of analog meters 40 are provided. The image 50 has a first area 50A which is an area in which the meter panel 51 is captured, and a second area 50B which is an area in which the periphery of the meter panel 51 is captured. In Fig. 5(a), the second area 50B is indicated by a large number of dots. The outline shape of the analog meters 40 is circular when viewed from the front.

[0046] As shown in FIG. 5( b ), the control device 10C detects a boundary 50C between a first region 50A and a second region 50B in the image 50, and extracts the first region 50A from the image 50. As shown in Fig. 5(c), the control device 10C detects the edge 40C, which is the circular outline of the analog meter 40, by pattern matching that recognizes a circle, and extracts an image of the analog meter 40 from the first area 50A. Pattern matching is classified as shape recognition, and is an image processing method that detects a search target similar to a reference pattern (model) registered in advance from within the image to be analyzed. Pattern matching makes it possible to detect a search target that has a similarity to the reference pattern that is equal to or higher than a set similarity.

[0047] <Step S102> Next, the control device 10C corrects the image of the analog meter 40 extracted in step S101 (step S102). As an example, the image of the analog meter 40 that was not photographed horizontally is rotated and corrected so that it is horizontal.

[0048] 6(a), the control device 10C performs ellipse approximation processing on the image of the analog meter 40. The ellipse approximation processing refers to processing for approximating a circular object photographed from an arbitrary direction with an ellipse by image processing.

[0049] As shown in FIG. 6(b), the control device 10C detects the coordinates of a major axis 40D and a minor axis 40E in the XY coordinate system of the image of the analog meter 40 approximated as an ellipse. As shown in Fig. 6(c), the control device 10C rotates and corrects the image of the analog meter 40 so that the coordinate of the major axis 40D coincides with the X-axis of the XY coordinate system, and the coordinate of the minor axis 40E coincides with the Y-axis of the XY coordinate system. The X-axis is a horizontal reference line corresponding to the horizontal direction. The Y-axis is a vertical reference line corresponding to the vertical direction.

[0050] <Step S103> Next, the control device 10C extracts an image of the indicator needle 40B from the image of the analog meter 40 corrected in step S102 (step S103).

[0051] As shown in FIG. 7(a), for example, the indicator 40B is divided into three parts. That is, the indicator 40B has an end portion 40B1, a support portion 40B2, and a tip portion 40B3. The end portion 40B1 and the tip portion 40B3 are located on opposite sides of the support portion 40B2. The tip portion 40B3 is a portion that points to the scale 40A. When the analog meter 40 is viewed from the front, the end portion 40B1 is a square (more precisely, a trapezoid), the support portion 40B2 is a circle, and the tip portion 40B3 is a triangle. The indicator 40B rotates around the support portion 40B2.

[0052] As shown in FIG. 7(b), the control device 10C detects an edge 40F1, which is the outline of the end portion 40B1 of the analog meter 40, by pattern matching that recognizes a quadrangle. The control device 10C detects an edge 40F2, which is the outline of the support portion 40B2 of the analog meter 40, by pattern matching that recognizes a circle. The control device 10C detects an edge 40F3, which is the outline of the tip portion 40B3 of the analog meter 40, by pattern matching that recognizes a triangle. The control device 10C extracts an image of the indicator needle 40B from the image of the analog meter 40, based on the detected edge 40F1 of the end portion 40B1, edge 40F2 of the support portion 40B2, and edge 40F3 of the tip portion 40B3.

[0053] <Step S104> Finally, the control device 10C reads the indication value from the image of the indicator 40B extracted in step S103 (step S104).

[0054] The control device 10C performs rectangular approximation processing on the image of the extracted pointer 40B shown in Fig. 8(a) Rectangular approximation processing refers to processing for approximating an object photographed from an arbitrary direction into a rectangle by image processing.

[0055] As shown in FIG. 8(b), the control device 10C sets a center line 40B5 extending along the longitudinal direction of a contour 40B4 of the indicator 40B which is approximated by a rectangle. As shown by the arrow in Figure 8(c), the control device 10C recognizes the direction in which the area of ​​the indicator needle 40B after extraction shown in Figure 8(a) goes from the wider side to the narrower side, i.e., the direction from the terminal end 40B1 to the tip end 40B3, as the direction indicated by the indicator needle 40B.

[0056] The control device 10C detects the angle θ between the portion of the center line 40B5 from the origin O to the tip O1 of the XY coordinate system and the X-axis of the XY coordinate system, and calculates the indicated value of the analog meter 40 based on the detected angle θ. The origin O corresponds to the center of the analog meter 40 when viewed from the front and the center of rotation of the indicator needle 40B. The portion of the center line 40B5 from the origin O to the tip O1 corresponds to the tip 40B3 of the indicator needle 40B. The X-axis is a reference line that serves as a reference when calculating the angle θ.

[0057] For example, the angle θ is "0°" when the portion of the center line 40B5 from the origin O to the tip O1 coincides with the positive part of the X-axis. The angle θ becomes a negative value when the portion of the center line 40B5 from the origin O to the tip O1 rotates counterclockwise with respect to the positive part of the X-axis. The angle θ becomes a positive value when the portion of the center line 40B5 from the origin O to the tip O1 rotates clockwise with respect to the positive part of the X-axis.

[0058] The control device 10C calculates the indication value of the analog meter 40 based on the table data 10A2. The table data 10A2 specifies the relationship between the angle θ and the indication value, and is set in advance. The table data 10A2 is stored in the storage device 10A. The control device 10C causes the indication value of the analog meter 40 corresponding to the detected angle θ to be displayed on the display 30D. The control device 10C also stores the calculated indication value of the analog meter 40 in a database constructed in the storage device 10A. In the database, the analog meter 40 is managed in association with identification information. The indication value is accumulated in the database for each analog meter 40.

[0059] This completes the reading process of the analog meter 40. <Effects of this embodiment> Therefore, according to this embodiment, the following effects can be obtained.

[0060] (1) The control device 10C extracts the indicator needle 40B from the image of the analog meter 40 by performing pattern matching using graphics for each of a plurality of parts of the indicator needle 40B that have different shapes, and calculates the indicated value of the analog meter 40 based on the angle θ between the extracted indicator needle 40B and the X-axis, which is a defined reference line. Therefore, unlike a type of device that reads the indicated value of an analog meter by comparing the image of the analog meter with a learning model created in advance, there is no need to create a learning model. Therefore, the indicated value of the analog meter 40 can be easily read. Also, unlike a type of reading system that permanently installs a camera and installs lighting at a predetermined angle to the analog meter, there are fewer equipment constraints and it is easy to introduce.

[0061] (2) When viewed from the front, the indicator 40B has three parts with different shapes, namely, a rectangular end portion 40B1, a circular support portion 40B2, and a triangular tip portion 40B3. Therefore, by performing pattern matching using graphics for each of the end portion 40B1, the support portion 40B2, and the tip portion 40B3, the indicator 40B can be extracted from the image of the analog meter 40.

[0062] (3) The control device 10C sets a center line 40B5 extending along the longitudinal direction of the indicator needle 40B, which is approximated to a rectangle, on the image of the analog meter 40. The control device 10C also recognizes the direction in which the area of ​​the indicator needle 40B extracted from the image of the analog meter 40 narrows as the direction indicated by the indicator needle 40B. The control device 10C can more accurately calculate the indicated value of the analog meter 40 based on the angle θ between the part of the center line 40B5 corresponding to the tip portion 40B3 and the X-axis.

[0063] (4) The memory device 10A stores table data 10A2 that defines the relationship between the angle θ between the portion of the center line 40B5 corresponding to the tip portion 40B3 and the X-axis and the indicated value of the analog meter 40. The control device 10C uses the table data 10A2 based on the angle θ to calculate the indicated value of the analog meter 40. By using the table data 10A2, the indicated value of the analog meter 40 can be calculated more easily.

[0064] (5) Prior to the process of extracting the image of the indicator needle 40B, the control device 10C horizontally corrects the inclination of the image of the analog meter 40. This makes it possible to more accurately calculate the indicated value of the analog meter 40.

[0065] (6) Prior to the process of extracting the image of the indicator needle 40B, the control device 10C extracts the analog meter 40 from the image of the analog meter 40. The control device 10C also approximates the extracted analog meter 40 to an ellipse, and rotates the image of the analog meter 40 so that the major axis 40D of the ellipse is horizontal. This makes it possible to correct the inclination of the image of the analog meter 40 to be horizontal.

[0066] (7) The image of the analog meter 40 stored in the storage device 10A includes the image of the analog meter 40 sent via the communication network 20 from the portable terminal 30 carried by the person who photographed the analog meter 40. The reading device 10 automatically reads the indicated value from the image of the analog meter 40 stored in the storage device 10A. For this reason, the worker only needs to photograph the analog meter 40 to be read with the portable terminal 30 and transmit the photographed image of the analog meter 40 to the reading device 10. This is convenient because the worker does not need to visually read the analog meter 40.

[0067] (8) By using pattern matching based on the figure, the influence of some shadow or halation can be ignored. Halation is a phenomenon in which a part of an object that is exposed to strong light becomes white and blurred when it is photographed. As shown in FIG. 9(a), it is possible that a part of the indicator needle 40B is hidden by a shadow or halation 40G. Even in this case, as shown in FIG. 9(b), the indicator needle 40B can be extracted by detecting the edge 40F1 of the end portion 40B1, the edge 40F2 of the support portion 40B2, and the edge 40F3 of the tip portion 40B3 through pattern matching based on the figure of the three parts (40B1, 40B2, 40B3) of the indicator needle 40B. Also, as shown in FIG. 10(a), it is possible that a part of the scale 40A is hidden by a shadow or halation 40G. Even in this case, as shown in FIG. 10(b), it is possible to extract the analog meter 40 by detecting the edge 40C of the analog meter 40 through pattern matching based on the figure.

[0068] <Other embodiments> This embodiment may be modified as follows. As shown in FIG. 11(a), the analog meter 40 may be photographed from obliquely above. Also, as shown in FIG. 11(b), the analog meter 40 may be photographed from the left or right side when viewed from the front. In this case, the following correction process may be performed in step S102 of FIG. 4. That is, the control device 10C performs ellipse approximation process on the image (edge ​​40C) of the analog meter 40 extracted in step S101. Next, as shown in FIG. 11(c), the control device 10C corrects the edge 40C in the image of the analog meter 40 that has been approximated to an ellipse so as to approach a circle. For example, the control device 10C calculates the length "a" of the major axis of the ellipse and the length "b" of the minor axis of the ellipse by image processing, and multiplies the ellipse by "a / b" in the minor axis direction. In this way, the scale 40A of the analog meter 40 is equally spaced, just like when viewed from the front. Therefore, it is possible to read the indicated value more accurately through the execution of the reading process in step S104 of FIG. 4.

[0069] As shown in Fig. 12(a), when an image of the analog meter 40 is not captured horizontally and an object that should be placed vertically is included in the image, the following correction process may be performed in step S102 of Fig. 4. That is, when an object that should be placed vertically is included in the image of the analog meter 40, the control device 10C rotates the image of the analog meter 40 so that the object is placed vertically. This makes it possible to correct the inclination of the image of the analog meter 40 to be horizontal.

[0070] For example, when a support member 60, which is a rod-shaped object that vertically supports an analog meter 40, is shown in the image, the control device 10C sets a center line 60A of the support member 60 on the image of the analog meter 40. The center line 60A extends along the extension direction of the support member 60, i.e., the vertical direction. Next, as shown in Fig. 12(b), the control device 10C rotates and corrects the image of the analog meter 40 so that the center line 60A coincides with or is parallel to the Y axis of the XY coordinate system. This allows the image of the analog meter 40 to be corrected so that it is horizontal.

[0071] When the image of the analog meter 40 is not captured horizontally and includes an object that should be placed horizontally, the following correction process may be performed in step S102 of Fig. 4. That is, when the image of the analog meter 40 includes an object that should be placed horizontally, the control device 10C rotates the image of the analog meter 40 so that the object is placed horizontally. This makes it possible to correct the inclination of the image of the analog meter 40 to be horizontal.

[0072] For example, although not shown in the drawings, when a support member, which is a rod-shaped object that horizontally supports analog meter 40, is shown in the image, control device 10C sets the center line of the support member on the image of analog meter 40. The center line extends along the extension direction of the support member, i.e., the horizontal direction. Control device 10C rotates and corrects the image of analog meter 40 so that the center line coincides with or is parallel to the X-axis of the XY coordinate system. This allows the image of analog meter 40 to be corrected so that it is horizontal.

[0073] Furthermore, when one side extending along the horizontal direction of the meter panel 51, which is an object that supports the analog meter 40 horizontally, is shown in the image, the control device 10C sets a reference line on the image of the analog meter 40 that is parallel to the one side extending along the horizontal direction of the meter panel 51. The control device 10C rotates and corrects the image of the analog meter 40 so that the reference line is parallel to the X-axis of the XY coordinate system. In this way, the image of the analog meter 40 can also be corrected so that it is horizontal.

[0074] If the image of the analog meter 40 is not captured horizontally, the following correction process may be performed in step S102 of FIG. 4. That is, as shown in FIG. 13(a), the scale 40A is arc-shaped when viewed from the front. The scale 40A is symmetrical about a line connecting the midpoint of the arc and the center point of the arc. For example, if the minimum value of the scale is "0" and the maximum value is "1", and one scale is "0.02", the midpoint of the arc is a position corresponding to the scale of "0.5". The scale 40A has a start point 40A1 corresponding to the minimum value and an end point 40A2 corresponding to the maximum value. Based on the configuration of the scale 40A, the control device 10C sets a reference line 40A3 that is a straight line connecting the start point 40A1 and the end point 40A2. After that, the control device 10C rotates the image of the analog meter 40 so that the set reference line 40A3 is horizontal. 13(b), the control device 10C rotates and corrects the image of the analog meter 40 so that the reference line 40A3 is parallel to the X-axis of the XY coordinate system. In this way, the image of the analog meter 40 can be corrected to be horizontal.

[0075] When the image of the analog meter 40 is not captured horizontally, and the scale 40A is arc-shaped but not line-symmetrical, the following correction process may be performed in step S102 of Fig. 4. That is, the control device 10C sets a reference line connecting the scale position that should be at the top when the analog meter 40 is installed horizontally and the center line of the arc, and rotates and corrects the image of the analog meter 40 so that the set reference line coincides with the Y axis of the XY coordinate system. In this way, the image of the analog meter 40 can be corrected so that it is horizontal.

[0076] In the present embodiment, the indicator 40B has three parts with different shapes (terminal part 40B1, support part 40B2, tip part 40B3), but the indicator 40B may have two parts with different shapes. For example, the indicator 40B is formed by connecting the terminal part 40B1, which is rectangular when viewed from the front, and the tip part 40B3, which is triangular. In this case, the control device 10C can extract the indicator 40B through pattern matching that detects a rectangle and a triangle. Incidentally, the control device 10C can also recognize the shape of each part of the indicator based on the number of vertices detected. In this way, although there are various shapes of the indicator 40B, the indicator 40B can be extracted by performing pattern matching by a figure for each of the parts of the indicator 40B with different shapes.

[0077] If the range of the graduations 40A is 180° or less in the rotation direction of the indicator 40B, and if the indicator 40B is a type that rotates around its end, the control device 10C does not need to execute a process for recognizing the direction indicated by the indicator 40B. This is because the angle θ between the indicator 40B and the X-axis varies within a range of 0° to 180°. In this case, the control device 10C can set a center line 40B5 extending along the longitudinal direction of the indicator 40B, which is approximated as a rectangle, on the image of the analog meter 40, and calculate the indicated value of the analog meter 40 based on the angle θ between the set center line 40B5 and the X-axis, which is a reference line.

[0078] In this embodiment, the reading device 10 executes the reading process to read the indicated value from the image of the analog meter 40, but the mobile terminal 30 may execute the reading process. In this case, the mobile terminal 30 functions as a reading device for the analog meter 40. The mobile terminal 30 reads the indicated value from the image of the analog meter 40 captured by the camera 30E, and transmits the read indicated value to the reading device 10. The reading device 10 functions as a management device that manages the indicated value of the analog meter 40 transmitted from the mobile terminal 30. [Explanation of symbols]

[0079] 10...Reading device 10A…Storage device 10A2...Table data 10C…Control device 20…Network 30. Mobile terminal 40…Analog meter 40A…scale 40A1…Start point 40A2…End point 40A3...Baseline 40B…Indicator needle 40B1…End part 40B2…Support part 40B3…Tip 40B5…Center line 40D…Long axis θ…Angle 51...Meter panel (object) 60...Support member (object)

Claims

1. A reading device for an analog meter having an arc-shaped scale and an indicator needle that rotates about a determined center of rotation to indicate a value on the scale, a storage device for storing an image of the analog meter; a control device that executes a process for reading the indicated value from the image of the analog meter stored in the storage device, The control device extracts the indicator from the image of the analog meter by performing graphical pattern matching for each of multiple parts of the indicator needle that have different shapes, and calculates the indicated value based on the angle between the extracted indicator needle and a determined reference line.

2. 2. An analog meter reader according to claim 1, wherein said indicator needle includes portions having at least two shapes selected from the group consisting of a square, a circular and a triangular shape when viewed from the front.

3. An analog meter reading device as described in claim 1 or claim 2, wherein the control device approximates the indicator needle extracted from the image of the analog meter into a rectangle, sets a center line extending along the longitudinal direction of the rectangularly approximated indicator needle for the image of the analog meter, and calculates the indication value based on the angle between the set center line and the reference line.

4. The indicator needle has an area that narrows from the distal end to the distal end when viewed from the front, An analog meter reading device as described in claim 3, wherein the control device recognizes the direction in which the area of ​​the indicator needle extracted from the image of the analog meter narrows as the direction indicated by the indicator needle, and calculates the indication value based on the angle between the part of the center line corresponding to the tip and the reference line.

5. the storage device stores table data defining a relationship between the angle and the instruction value; 4. The analog meter reader according to claim 3, wherein the control device calculates the indicated value by using the table data based on the angle.

6. 6. The analog meter reading device according to claim 1, wherein the control device corrects a tilt of the image of the analog meter to a horizontal position prior to processing to extract an image of the indicator needle.

7. 7. An analog meter reading device as described in claim 6, wherein the control device extracts the analog meter from the image of the analog meter, approximates the extracted analog meter to an ellipse, and rotates the image of the analog meter so that the major axis of the ellipse is horizontal.

8. 7. An analog meter reading device as described in claim 6, wherein when the image of the analog meter includes an object that should be placed horizontally or vertically, the control device rotates the image of the analog meter so that the object is horizontal or vertical.

9. the scale is symmetrical about a line connecting a midpoint of the arc and a center point of the arc, and has a start point corresponding to a minimum value of the scale and an end point corresponding to a maximum value of the scale, An analog meter reading device as described in claim 6, wherein the control device sets a reference line which is a straight line connecting the starting point and the end point for the image of the analog meter, and rotates the image of the analog meter so that the set reference line is horizontal.

10. An analog meter reading device as described in any one of claims 1 to 5, wherein the control device extracts the analog meter from the image of the analog meter prior to the process of extracting the image of the indicator needle, approximates the extracted analog meter to an ellipse, and corrects the image of the analog meter so as to make the approximated ellipse closer to a circle.

11. An analog meter reading device as described in any one of claims 1 to 10, wherein the image of the analog meter stored in the memory device includes an image of the analog meter sent via a network from a mobile terminal carried by a person photographing the analog meter.

12. A method for reading an analog meter having an arc-shaped scale and an indicator needle that rotates about a determined center of rotation to indicate a value on the scale, comprising the steps of: extracting the indicator needle from the image of the analog meter stored in a storage device by performing pattern matching using graphics for each of a plurality of parts having different shapes of the indicator needle; and calculating the indicated value based on an angle between the indicator needle and a defined reference line extracted from an image of the analog meter.

13. 1. An analog meter reading program that causes a computer to execute a process for reading an indicated value from an image of an analog meter having an arc-shaped scale and an indicator needle that rotates about a determined center of rotation to indicate an indicated value on the scale, the process comprising: extracting the indicator from the image of the analog meter by performing pattern matching using a graphic for each of a plurality of parts of the indicator that have different shapes; and calculating the indicated value based on an angle between the indicator needle extracted from an image of the analog meter and a defined reference line.

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