JP2020173733A - Analog meter reading device - Google Patents

Abstract

To provide an analog meter reading device that reads an indicated value of an analog meter while suppressing production cost and power consumption.SOLUTION: An analog meter reading device 1 includes a reading unit 10 comprising: a plurality of LED elements 14 regularly arranged along a prescribed direction; and a plurality of photodiodes 13 regularly arranged along the plurality of LED elements 14. The reading unit 10 reads an indicator needle meter in a state of being mounted on a cover glass surface facing a dial plate of the indicator needle meter.SELECTED DRAWING: Figure 3

Description

The present invention relates to an analog meter reader.

Conventionally, a technique has been disclosed that can automatically read a value indicated by an indicator needle of an analog meter (hereinafter referred to as "indication value") by image processing and obtain a digital signal suitable for computer management (Patent Document). 1).

The technology of Patent Document 1 uses a camera installed at a distance from the analog meter, and as images taken by the analog meter, a reference image having a known indicated value and a measured image in which the indicator needle is rotated. The two images of, and are obtained, and the indicated value indicated by the indicator needle is obtained by comparing the two images.

Further, there is disclosed a technique that can be retrofitted to an analog meter, can read the indicated value indicated by the indicator needle without impairing the calibration state of the analog meter, and can take out the indicated value to the outside without contact (Patent Document 2). ).

The technique of Patent Document 2 detects the relative position of the indicator needle with respect to the proximity sensor by attaching a conductive target to the indicator needle and attaching a measurement IC tag unit including a proximity sensor to the cover glass surface of the analog meter. By doing so, the indicated value is output.

Japanese Unexamined Patent Publication No. 2004-133560 JP-A-2017-203775

The technique of Patent Document 1 cannot read the reading of the analog meter in a place where there is no lighting equipment such as at night or in a dark place. Further, when the illumination light for the analog meter is not appropriate, such as when the analog meter is directly irradiated with sunlight, there is a problem that strong reflected light is generated on the cover glass surface and the indicated value cannot be read. Further, since the technique of Patent Document 1 uses a camera, there is a problem that the production cost is high and the power consumption is large.

In the technique of Patent Document 2, when the indicator needle of the analog meter is not made of a conductive material, the indicated value cannot be detected even if the measurement IC tag unit is attached to the cover glass surface. Therefore, the user needs to open the cover glass surface of the analog meter and attach the conductive target directly to the indicator needle, but there is a problem that the work load is very large.

The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide an analog meter reader capable of reading an analog meter reading in real time while suppressing production cost and power consumption. And.

The analog meter reading device according to the present invention includes a plurality of light emitting elements regularly arranged along a predetermined direction, and a plurality of light receiving elements regularly arranged in a predetermined direction or along the plurality of light emitting elements. The reading unit includes a reading unit having a, and the reading unit reads the analog meter in a state of being mounted at a predetermined position on a transparent member of the analog meter.

The present invention can read the reading of the analog meter while suppressing the production cost and the power consumption.

(A) is a front view of the analog meter reading device of the first embodiment attached to the indicator needle meter, and (B) is an external side view thereof. It is a figure which shows the reading surface of a reading part. It is a block diagram which shows the functional structure of an analog meter reader. It is a flowchart which shows the rotation center identification routine of the indicator needle, and the conversion table creation routine. It is a figure which shows an example of the scale area of the indicator needle meter. It is a figure which shows the scale area developed in the polar coordinate plane. It is a figure which shows the conversion table. It is a flowchart which shows the reading process routine. It is a schematic diagram when the indicator needle of the indicator needle meter exists in the central part of one detection area of a photodiode, and the figure which shows the output signal of each photodiode at that time. It is a schematic diagram when the indicator needle of an analog meter exists in the overlapping part of the detection area of two photodiodes, and the figure which shows the output signal of each photodiode at that time. It is a figure which shows the cross-sectional shape of the photodiode which concerns on 2nd Embodiment. (A) is a schematic diagram showing a light-sensitive region of a photodiode when the photodiode does not have a lens, and (B) is a schematic diagram showing a light-sensitive region when a lens is formed on the photodiode. It is a figure which shows the light-sensitive region which has a different diameter. It is a figure which shows the reading part of the analog meter reading apparatus which concerns on 3rd Embodiment. (A) is a plan view of the reading unit, and (B) is a side view thereof. It is a figure which shows the reading part of the analog meter reading apparatus which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1A is a front view of the analog meter reading device 1 of the first embodiment attached to the indicator needle meter 100, and FIG. 1B is an external side view thereof. The analog meter reading device 1 irradiates the indicator needle meter 100 with light to detect the position information of the indicator needle 101, and the reading unit 10 and the indicated value indicated by the indicator needle 101 based on the position information detected by the reading unit 10. It includes a control unit 30 for calculating.

The indicator needle meter 100 includes an indicator needle 101, a scale plate 102 that displays a physical quantity corresponding to a position indicated by the indicator needle 101, and a cover glass 103 for protecting the indicator needle 101. The indicator needle 101 rotates with respect to a predetermined rotation center on a plane at a predetermined distance from the display surface side of the scale plate 102. The cover glass 103 covers the display surface side of the scale plate 102 so as to include the indicator needle 101.

The scale plate 102 of the indicator needle meter 100 is white, and the indicator needle 101 is black. Therefore, the light emitted to the indicator needle meter 100 is reflected by the scale plate 102 and absorbed by the indicator needle 101. The reading unit 10 detects the position information of the indicator needle 101 of the indicator needle meter 100 by utilizing the light reflection characteristic of the indicator needle meter 100.

The reading unit 10 is an arc strip-shaped (doughnut-shaped) member having a substantially uniform thickness as a whole, a hole portion formed in the center, and a predetermined width in the radial direction. One of the two side surfaces of the reading unit 10 is directly mounted on the cover glass 103 surface of the indicator needle meter 100, and is a side surface (reading surface) that optically detects the position information of the indicator needle 101 of the indicator needle meter 100. ). The other side surface of the above two side surfaces is a side surface (marker surface) exposed to the outside and on which the marker 10M is printed.

The reading surface of the reading unit 10 is the cover glass 103 surface on the opposite side of the scale plate 102 of the indicating needle meter 100 so that the center of the reading unit 10 coincides with the rotation center of the indicating needle 101 of the indicating needle meter 100. Mounted directly on top. At this time, the marker surface of the reading unit 10 is on the front side. In the present embodiment, four rectangular markers 10M are printed on the marker surface of the reading unit 10. The four markers 10M are arranged at the positions of the vertices of the square, and the intersections of the diagonal lines of the square coincide with the center of the reading unit 10.

FIG. 2 is a diagram showing a reading surface of the reading unit 10. The reading unit 10 includes a disk-shaped storage case 12 in which a small hole portion 11 is formed, a plurality of photodiodes 13 arranged in an arc shape along the outer peripheral portion of the storage case 12, and a plurality of photodiodes and holes. A plurality of LED elements 14 arranged in an arc shape between the portions are provided.

The storage case 12 has a circular storage bottom 12a in which a small hole 11 is formed in the center and a plurality of photodiodes 13 and LED elements 14 are installed, and an outer peripheral wall 12b formed along the outer peripheral portion of the circular storage bottom 12a. And an inner peripheral wall 12c formed along the inner peripheral portion of the circular storage bottom 12a. The height of the outer peripheral wall 12b and the inner peripheral wall 12c is larger than the height from the arrangement surface of the photodiode 13 and the LED element 14. Therefore, when the reading unit 10 is attached to the cover glass 103, the ends of the outer peripheral wall 12b and the inner peripheral wall 12c are adhered to the cover glass 103. That is, the photodiode 13 and the LED element 14 do not have to come into contact with the cover glass 103, and damage due to contact is avoided.

In the reading unit 10, 21 photodiodes 13 having index numbers 0 to 20 are arranged in an arc shape. The index number is used not only to identify one photodiode 13 out of the 21 photodiodes 13, but also as position information of the corresponding photodiode 13. Therefore, although the details will be described later, the index number is used when calculating the indicated value of the indicator needle meter 100.

Further, the relative positional relationship between each photodiode 13 in the reading unit 10 and each marker 10M printed on the marker surface of the reading unit 10 is predetermined. Therefore, when the reading unit 10 is attached to the indicating needle meter 100, if the position of each marker 10M with respect to the indicating needle meter 100 is determined, the position of each photodiode 13 with respect to the indicating needle meter 100 is also uniquely determined.

The plurality of LED elements 14 are arranged in an arc shape inside a concentric circle with respect to the plurality of photodiodes 13. In this embodiment, the number of photodiodes 13 is larger than the number of LED elements 14. However, the number of each of the photodiode 13 and the LED element 14 is not particularly limited.

Further, in the present embodiment, the photodiode 13 is arranged outside the LED element 14, but the LED element 14 may be arranged inside the photodiode 13.

FIG. 3 is a block diagram showing a functional configuration of the analog meter reading device 1. The reading unit 10 detects the position information of the indicating needle of the indicating needle meter 100, and supplies the detected position information to the control unit 30. The control unit 30 calculates the indicated value of the indicator needle meter 100 based on the position information supplied from the reading unit 10, and transmits the indicated value to the server device 200 by wireless communication. As a result, the server device 200 aggregates and manages the indicated values of the plurality of indicating needle meters 100 in real time.

The reading unit 10 controls switching between a plurality of photodiodes 13 that receive the reflected light from the indicator needle meter 100, a plurality of LED elements 14 that irradiate the indicator needle meter 100 with light, and an output signal of each photodiode 13. It is provided with a photodiode control unit 15 and an LED drive unit 16 for driving each LED element 14.

The control unit 30 analog-to-digital / outputs the output signals from the storage battery 31, the photodiode (PD) switching unit 32, and the PD switching unit 32, which store power for supplying power to each circuit in the control unit 30 and the reading unit 10. An A / D converter 33 that performs digital (A / D) conversion, a CPU 34, an LED control unit 35 that controls lighting / extinguishing of the LED element 14, a RAM 36 that is a data work area, and a ROM 37 that stores a program. A wireless communication unit 38 that wirelessly communicates with an external device such as a server device 200.

The analog meter reading device 1 configured as described above calculates the indicated value of the indicator needle meter 100 according to the following procedure.

The reading unit 10 detects the position information of the indicator needle 101 of the indicator needle meter 100 in a state of being mounted on the front center portion of the indicator needle meter 100. Ideally, the reading unit 10 is preferably located at a position that is not displaced in the radial direction and the rotation direction with respect to the rotation center of the instruction needle 101 of the instruction needle meter 100. However, in reality, the reading unit 10 is mounted at a position deviated to some extent in the radial direction and the rotational direction described above. Therefore, the following processes (1) and (2) are required.

(1) In order to accurately calculate the indicated value of the indicating needle meter 100, it is necessary to determine in advance whether or not the deviation in the radial direction and the rotational direction is within the allowable range.
(2) The position information of the indicator needle 101 detected by the reading unit 10 is merely the position information of the indicator needle 101 of the indicator needle meter 100 based on the index number of the photodiode 13, and the actual indicated value can be calculated. , It is necessary to create a conversion table for converting the position information to the indicated value.

Therefore, specifically, the following processing is performed.
First, the user attaches the reading unit 10 of the analog meter reading device 1 to the front center portion of the indicator needle meter 100.

Next, the user uses, for example, a mobile terminal to take a picture of the indicator needle meter 100 to which the reading unit 10 is mounted. The image of the indicator needle meter 100 (hereinafter, referred to as “meter image”) generated by the photographing is transmitted to the server device 200 that manages each indicator needle meter 100.

The CPU 201 of the server device 200 rotates the indicator needle 101 for determining whether or not the above-mentioned radial and rotational deviations of the reading unit 10 are within an allowable range based on the meter image transmitted from the mobile terminal. Identify the center. Further, the CPU 201 of the server device 200 creates a conversion table for converting the position information of the indicator needle 101 of the indicator needle meter 100 into the indicated value based on the index number of the photodiode 13. Here, the conversion table refers to a table for converting the position information of the indicator needle 101 of the indicator needle meter 100 into the indicated value of the indicator needle meter 100.

FIG. 4 is a flowchart showing a rotation center identification routine and a conversion table creation routine of the indicator needle 101. In step S1, the CPU 201 determines whether or not a meter image has been acquired from the mobile terminal that has captured the indicator needle meter 100, and waits until the meter image is acquired. When the CPU 201 acquires the meter image, the CPU 201 proceeds to the next step S2.

In step S2, the CPU 201 corrects the distortion caused by the shooting direction and obtains a meter image equivalent to the meter image generated when the mobile terminal shoots the indicator needle meter 100 from the front. The process for correcting the distortion caused by the photographing direction corresponds to, for example, the technique disclosed in Japanese Patent Application Laid-Open No. 2006-12133.

In step S3, the CPU 201 performs a binarization process on the meter image. Specifically, the CPU 201 extracts a luminance component from the meter image, and for each pixel of the meter image, if the value of each luminance component is larger than a predetermined threshold value, it sets "1", otherwise it sets "0". Set.

In step S4, the CPU 201 extracts the scale region MR1 (see FIG. 5 described later) from the binarized meter image. Here, the scale area means an area on the scale plate 102 on which a scale showing the correspondence between the position indicated by the indicator needle 101 and the indicated value is drawn.

FIG. 5 is a diagram showing an example of the scale region MR1 of the indicator needle meter 100. In the present embodiment, the scale region MR1 is used as a template of an arc band described by using four parameter values of an outer radius a, an inner radius b, a central angle φ− to the left of the perpendicular, and a central angle φ + to the right. Is modeled. From this, the center position of the scale region MR1 becomes the same as the rotation center of the indicator needle 101.

The template of the scale area MR1 is not limited to the shape of the arc band specified by the four parameters (a value, b value, φ− value and φ + value). That is, the template of the scale region MR1 may have a shape other than the arc band as long as it can identify the rotation center of the indicator needle 101.

The CPU 201 searches for the optimum template position in the binarized meter image by changing the center position of the template and the four parameter values. Then, when the pixel value distribution in the template becomes uniform, the CPU 201 extracts the scale region MR1 according to the center position of the template and the four parameter values.

Specifically, when searching for a template, the CPU 201 divides the internal area of the template into several subregions, and the average pixel value in each subregion becomes substantially constant over the entire interior of the template. In addition, the scale region MR1 is extracted as the center position, a value, b value, φ− value, and φ + value at that time.

In step S5, the CPU 201 identifies the rotation center of the indicator needle 101 using the scale region MR1 (a value, b value, φ− value and φ + value) extracted in step S4. In the present embodiment, the center of rotation of the indicator needle 101 coincides with the center position of the arc band-shaped template that models the scale region MR1. Therefore, the CPU 201 identifies the rotation center of the indicator needle 101 by specifying the center position of the template of the scale region MR1 extracted in step S4.

In step S6, the CPU 201 detects the deviation of the mounting position of the reading unit 10 with respect to the rotation center of the indicator needle 101 based on the meter image. Here, the deviation of the mounting position of the reading unit 10 is defined by the translation deviation Δr from the rotation center of the indicating needle 101 and the rotation deviation Δθ of the reading unit 10 from the vertical line of the indicating needle meter 100.

The translation deviation Δr and the rotation deviation Δθ are calculated based on the four rectangular markers 10M printed in advance at predetermined positions on the marker surface of the reading unit 10. Specifically, the CPU 201 calculates the position information of the center of the reading unit 10 from the position information of the four markers 10M in the meter image, and translates the translation deviation Δr as the distance from the position information to the rotation center of the indicator needle 101. Is calculated. Further, the CPU 201 calculates the rotation deviation Δθ as the slope of a straight line connecting the two markers 10M arranged in the vertical direction or the horizontal direction with reference to the above-mentioned perpendicular line.

In the present embodiment, as a marker for detecting the deviation of the mounting position of the reading unit 10, a rectangular marker 10M pre-printed at a predetermined position on the marker surface of the reading unit 10 is used, but the present invention is limited to this. It's not something. For example, when the reading unit 10 is attached to each of the plurality of indicating needle meters 100 and a unique identifier is assigned to each reading unit 10, a QR code (registered trademark) may be used as the marker. The QR code (registered trademark) is a two-dimensional bar code in which a unique identifier is encoded and is printed at a predetermined position on the marker surface of the reading unit 10. On the other hand, the CPU 201 may detect the deviation of the mounting position of the reading unit 10 by using the markers at the three corners of the QR code (registered trademark) in the meter image. In this case, the CPU 201 not only detects the deviation of the mounting position of the reading unit 10, but also can acquire the unique identifier of the reading unit 10.

In step S7, the CPU 201 determines whether or not the deviation of the mounting position of the reading unit 10 is within the allowable range. Specifically, the CPU 201 determines whether or not both the translation deviation Δr and the rotation deviation Δθ are equal to or less than a predetermined threshold value. Then, when the translation deviation Δr and the rotation deviation Δθ are both equal to or less than the predetermined threshold value, the process proceeds to step S9, and when at least one of the translation deviation Δr and the rotation deviation Δθ is not equal to or less than the predetermined threshold value, the process proceeds to step S8.

The respective threshold values of the translation deviation Δr and the rotation deviation Δθ are determined by the number of photodiodes 13 and LED elements 14 mounted on the reading surface of the reading unit 10, the arrangement location, and the indicator needle meter 100 required for the reading unit 10. It is determined by the reading accuracy and is not a particularly limited value.

In step S8, the CPU 201 performs a process for instructing the user to reattach the reading unit 10. The process for instructing reattachment corresponds to, for example, a process of sending an e-mail instructing reattachment to a pre-registered e-mail address, a process of displaying a reattachment instruction on a predetermined monitor screen, and the like. .. Then, this routine ends.

On the other hand, in step S9, the CPU 201 executes the polar coordinate conversion process of the position information of the scale region MR1 and the photodiode 13 shown in FIG.
Specifically, the CPU 201 develops the arc band-shaped scale region MR1 extracted from the meter image on a polar coordinate plane with the central angle with respect to the perpendicular as the horizontal axis and the radius method as the vertical axis.

FIG. 6 is a diagram showing a rectangular scale region MR2 developed on a polar coordinate plane. The scale region MR2 is represented by a rectangular region having a width from φ− to φ + on the horizontal axis and a height from a to b on the vertical axis.

The plurality of photodiodes 13 arranged in the reading unit 10 do not appear in the meter image. However, the position information of each photodiode 13 is associated with the position information of the four markers 10M printed on the reading unit 10. That is, if the position information of the four markers 10M is detected, the position information of each photodiode 13 is also detected.

Therefore, the CPU 201 detects the position information of each of the four markers 10M using the meter image, detects the position information of each photodiode 13 based on the position information, and obtains the position information of these photodiodes 13. Expand to a polar plane.

For example, when 21 photodiodes 13 are arranged in the reading unit 10 at equal intervals in an arc shape, as shown in FIG. 6, a rectangular scale region MR2 is arranged on the polar coordinate plane described above, and the scale is concerned. Twenty-one photodiodes 13 (0th to 20th) are arranged at equal intervals along the longitudinal direction of the region MR2. At this time, the tenth position information (intermediate position) of the photodiode 13 corresponds to the position information of the rotation deviation Δθ = 0 ((φ +) = (φ−) = 0). This indicates a state in which the reading unit 10 is mounted without deviation with respect to the rotation center of the indicator needle 101 of the indicator needle meter 100. That is, the deviation of the mounting position of the reading unit 10 is within the allowable range and can be ignored in practice (Δr, Δθ = 0).

In step S10, the CPU 201 creates a conversion table for converting the position information of the indicator needle 101 of the indicator needle meter 100 based on the index number of the photodiode 13 into an indicated value. Specifically, the CPU 201 recognizes the scale numbers in the vicinity of the scale region MR2 as numerical values using the meter image, and associates the recognized numerical values with the position information of the scale numbers on the polar coordinate plane.

In this embodiment, a known OCR (Optical Character Recognition) technique is used. Further, the position information of the scale numbers is converted into the polar coordinate value ψ with reference to the perpendicular line of the indicated value meter 100. Then, the position information of the scale numbers (polar coordinate value ψ) and the numerical values of the scale numbers are associated with each other. It should be noted that such association is performed for all the scale numbers in the vicinity of the scale region MR2.

In general, the scale number is often displayed only as a value corresponding to a typical rotation angle of the indicator needle 101. From this, the position information of the scale numbers is not limited to the value of the position information as it is detected from the recognition of the scale numbers, but the values deviated by 5 °, 10 °, 15 °, 30 °, and 45 ° with respect to the perpendicular line. It may be replaced with (a typical divisor of 90 ° or a multiple thereof).

Finally, the CPU 201 creates a conversion table that converts the position information of the indicator needle 101 of the indicator needle meter 100 based on the index number of the photodiode 13 into the indicated value by using all the information developed on the polar coordinate plane.

FIG. 7 is a diagram showing a conversion table. The conversion table is composed of an index number of the photodiode 13 corresponding to the position information of the indicator needle 101 of the indicator needle meter 100, a rotation angle based on a perpendicular line, and an instruction value corresponding to the rotation angle.

Here, the index number of the photodiode 13 and the rotation angle with respect to the perpendicular line are values predetermined by mounting on the reading unit 10.
On the other hand, a plurality of typical rotation angles and indicated values (recognized numerical values) corresponding to them are acquired by the above-described processing. Further, other rotation angles and the indicated values corresponding to them are obtained by linear interpolation using the acquired rotation angles and the indicated values corresponding to them.

Therefore, the CPU 201 creates the conversion table shown in FIG. 7 by associating the index number of the photodiode 13 thus obtained, the rotation angle with respect to the perpendicular line, and the indicated value corresponding to the rotation angle.

Although the rotation angle with respect to the perpendicular is shown in FIG. 7 for convenience of explanation, the rotation angle may be omitted from the actual conversion table. That is, if the relationship between the index number of each photodiode 13 and the indicated value is known, there is no problem even if the rotation angle with respect to the perpendicular is omitted from the conversion table.

By the way, the conversion table creation processing routine shown in FIG. 4 is applied when the indicated value meter 100 to which the reading unit 10 is mounted is unknown. Therefore, when the indicated value meter 100 is known and the conversion table for the known indicated value meter 100 has been created by the conversion table creation processing routine shown in FIG. 4, the scale area MR1 of the indicated value meter 100 is created. For the indicated value meter having the same scale area as the above, only the mounting position deviation of the reading unit 10 needs to be evaluated.

Further, if the conversion table has already been created and the required reading accuracy of the indicated value is not high, and as a result, the deviation at the time of mounting can be sufficiently tolerated, the rotation center identification routine of the indicator needle shown in FIG. And the conversion table creation processing routine is unnecessary.

The server device 200 transmits the conversion table created as described above to the indicator needle meter reading device 1 by wireless communication. As a result, the analog meter reading device 1 calculates the reading value of the indicating needle meter 100 from the index number of the photodiode 13 using the conversion table transmitted from the server device 200. Specifically, the analog meter reading device 1 calculates the reading value of the indicating needle meter 100 by executing the reading processing routine shown below.

FIG. 8 is a flowchart showing a reading processing routine.
In step S11, the CPU 34 of the control unit 30 determines whether or not the predetermined measurement time has come, and waits until the measurement time comes. The measurement time may be a time repeated at predetermined time intervals or a preset time. When the CPU 34 determines that the measurement time has come, the process proceeds to step S12.

In step S12, the CPU 34 turns on the switch of the power supply line from the storage battery 31 to the reading unit 10 to start supplying power to the reading unit 10.

In step S13, the CPU 34 controls the LED drive unit 16 of the reading unit 10 to light all the LEDs 14. As a result, the indicator needle meter 100 is irradiated with light.

In step S14, the CPU 34 controls the photodiode control unit 15 of the reading unit 10 to read a signal from each photodiode 13 according to the amount of received light. The signal read from each photodiode 13 is supplied to the PD switching unit 32 of the control unit 30.

Further, the CPU 34 controls the PD switching unit 32 so as to sequentially switch and output the signals of the photodiodes 13 having index numbers 0 to 20 from the signals supplied from the photodiodes 13. The signal output from the PD switching unit 32 is analog-to-digital converted by the A / D converter 33 and supplied to the CPU 34. As a result, the CPU 34 receives the signals of the photodiodes 13 having index numbers 0 to 20.

FIG. 9A is a schematic diagram when the indicator needle 101 of the indicator needle meter 100 is located in the center of one detection region of the photodiode 13, and FIG. 9B is an output signal of each photodiode 13 at that time. It is a figure which shows.

In the figure, the small white circle indicates the detection region of the photodiode 13, and the square in the center of the small white circle indicates the photodiode 13. The large black circle indicates the light irradiation region by the LED element 14, and the square in the center of the large black circle indicates the LED element 14. The same applies to FIG. 10, which will be described later.

When the indicator needle of the indicator needle meter 100 is located in the center of one detection area of the photodiode 13, the output signal of the photodiode 13 becomes low level. The output signals of the other photodiodes 13 are at a high level. As a result, it can be seen that the indicator needle 101 of the indicator needle meter 100 is located at a position where the output signal corresponds to the low-level photodiode 13.

FIG. 10A is a schematic diagram when the indicator needle 101 of the indicator needle meter 100 exists in the overlapping portion of the detection regions of the two photodiodes 13, and FIG. 10B is an output signal of each photodiode 13 at that time. It is a figure which shows.

When the indicator needle 101 of the indicator needle meter 100 is present in the overlapping portion of the detection areas of the two photodiodes 13, the output signals of the two photodiodes 13 are at the middle level. The output signals of the other photodiodes 13 are at a high level. As a result, it can be seen that the indicator needle 101 of the indicator needle meter 100 is located between the positions where the output signals correspond to the two photodiodes 13 at the middle level.

As described above, the indicator needle of the indicator needle meter 100 may be detected in one detection region of the photodiode 13 or may be detected in two detection regions, respectively. Therefore, in consideration of these situations, the CPU 34 of the control unit 30 detects the position information of the indicator needle 101 from the output signal of each photodiode 13 via the index number of the photodiode 13.

In step S15, the CPU 34 detects the position information of the indicator needle 101 of the indicator needle meter 100 based on the output signals of the photodiodes 13 having index numbers 0 to 20.

Here, first, the CPU 34 detects the position information of the indicator needle 101 of the indicator needle meter 100 by using the output signal of each photodiode 13 and the index numbers 0 to 20 of each corresponding photodiode 13. Unlike the index number of the photodiode 13, this position information is not limited to an integer and may be a value including a decimal number. Next, the CPU 34 calculates an instruction value corresponding to the position information of the instruction needle 101 with reference to the conversion table shown in FIG. 7.

The method for detecting the position information of the indicator needle 101 is not particularly limited, but there are, for example, the following methods when the detection regions of the adjacent photodiodes 13 overlap.

(Detection method of indicator needle position information 1)
The CPU 34 can detect the position information of the indicator needle 101 by using the weighted average as follows. For example, the CPU 34 first selects, among the output signals of each photodiode 13, an output signal affected by the indicator needle 101, for example, an output signal whose level is equal to or less than a predetermined threshold value and the corresponding photodiode 13.

Next, the CPU 34 weights the index number of the selected photodiode 13. Here, the lower the level of the output signal, the larger the weight of the index number, and the higher the level of the output signal, the smaller the weight of the index number.

Finally, the CPU 34 calculates a weighted average of each weighted index number. The calculated weighted average value corresponds to the position information of the indicator needle 101.

(Detection method of indicator needle position information 2)
When the detection regions of more adjacent photodiodes 13 overlap, the CPU 34 can also detect the position information of the indicator needle 101 using the maximum likelihood method as follows.

First, with reference to the photodiode 13 corresponding to the lowest level output signal among the output signals of each photodiode 13, five continuous photodiodes 13 are selected so that the reference photodiode 13 is at the center. .. Then, each of i = -2 relative index number of five photodiodes 13 selected, the -1,0,1,2 each _Y -2 the level of the output signal of the photodiode 13, Y _- Let ₁ , Y ₀ , Y ₁ , and Y ₂ . The index number of the reference photodiode 13 is i = 0, and the output signal level thereof is Y ₀ .

Next, with the index number i as an independent variable, the maximum likelihood model function for the levels of the five output signals is defined by a parabola (quadratic function) such as the following equation.

y = a · i ² + b · i + c

Here, the maximum likelihood model function is a model function that can most accurately express the levels of all the output signals of the five selected photodiodes 13 based on the least squares method. Here, the substantial index number of the photodiode 13 that minimizes the output signal level is i (= i _min ) when the parabolic value is minimized.

That is, from y'= 2a · i _min + b = 0

i _min = −b / 2a
= -0.7 x (-2Y _-2 -Y _-1 + Y ₁ + 2Y ₂ )
/ (2Y- _2- Y _-1 -2Y _0- Y ₁ + 2Y ₂ )
Will be.

For example, the output signal level Y ₀ of the photodiode 13 with index number 7 is the minimum (0.9 μA), and Y _-2 , Y _-1 , Y ₀ , Y ₁ , and Y ₂ are 52.9 μA and 16.9 μA, respectively. , 0.9 μA, 4.9 μA, and 28.9 μA, i _min = 0.3.

_imin corresponds to the amount of deviation as an index number from the reference photodiode 13. From this, the substantial index number of the photodiode 13 at which the level of the output signal becomes the minimum value, that is, the position information of the indicator needle 101 becomes the index number 7 + _imin = 7.3.

When the row of photodiodes 13 overlaps not only the portion in the tip direction of the indicator needle 101 but also the portion in the root direction, there are two places where the level of the output signal is minimized. In this case, the portion of the indicator needle 101 in the tip direction is narrower than the portion in the root direction. This corresponds to the degree of spread of the parabola in the maximum likelihood model function described above.

Therefore, in the maximum likelihood model function obtained in the portion in the tip direction and the portion in the root direction of the indicator needle 101, a is obtained as shown in the following equation.
a = 1/14 × (2Y- _2- Y _-1 -2Y _0- Y ₁ + 2Y ₂ )

Then, the substantial index number of the photodiode 13 may be obtained from the maximum likelihood model function in which the value of a is larger, in other words, the extent of the corresponding parabola is smaller.

In the present embodiment, the position information of the indicator needle 101 is obtained by using the output signals of the five photodiodes 13, but the number of the photodiodes 13 is not particularly limited.

Further, the indicator needle meter 100 is premised on having a black indicator needle 101 on the white scale plate 102, but is not limited to such a configuration. For example, it is also possible to use an indicator needle meter having a black scale plate and a white indicator needle. In this case, the level of the output signal of the photodiode at or near the position of the indicator needle becomes high. Therefore, by detecting the position information of the photodiode 13 that maximizes the output signal level, the position information of the indicator needle is detected.

In this embodiment, a parabola is assumed as the maximum likelihood model function, but the present invention is not limited to this. For example, the maximum likelihood model function may be any function having a minimum value (or maximum value) in the vicinity of the photodiode with respect to the relative index number (i = 0).

Further, in the present embodiment, it is assumed that when the indicator needle 101 does not exist in the vicinity, the light receiving amount of each photodiode 13 is the same and the level of each output signal becomes a predetermined default value. However, in reality, even if the amount of received light is the same, the level of the output signal may vary due to individual differences of each photodiode. Further, when a scale number or a manufacturer's logo mark is printed in the light-sensitive area of the photodiode on the scale plate, the light reflection is hindered by the scale number or the logo mark. In this case, the level of the output signal as the default value becomes smaller than that of the periphery even though there is no indicator needle.

Therefore, instead of directly applying the above calculation to the output signal strength of the photodiode, the difference information obtained by subtracting the output signal strength of the photodiode as the default value from the detected output signal strength of the optical sensor is used as described above. Such operations may be applied.

After detecting the position information of the instruction needle 101 as described above, the CPU 34 calculates the instruction value by converting the position information of the instruction needle 101 into the instruction value with reference to the conversion table. This conversion table is created by the conversion table creation routine shown in FIG.

In step S16, the CPU 34 determines whether or not the indicated value is abnormal (outside the preset range). If it is determined that the indicated value is abnormal, the process returns to step S14, the signal is read again from each photodiode 13, and the indicated value is calculated again. If the indicated value is not abnormal, the process proceeds to step S17. If the indicated value becomes abnormal a predetermined number of times in succession, the process proceeds to step S18 without returning to step S14.

In step S17, the CPU 34 transmits the calculated instruction value to the server device 200 via the wireless communication unit 38. As a result, the server device 200 can constantly manage the indicated value of each indicator needle meter 100.

In step S18, the CPU 34 controls the LED drive unit 16 of the reading unit 10 to turn off all the LEDs 14.

In step S19, the CPU 34 turns off the switch of the power supply line from the storage battery 31 to the reading unit 10 to stop the power supply to the reading unit 10. Then, the process returns to step S11. After that, the process of step S11 and the like is repeated again.

As described above, in the analog meter reading device 1 according to the first embodiment, the position information of the indicating needle 101 of the indicating needle meter 100 is provided by the reading unit 10 having the photodiode 13 and the LED element 14 without using the image sensor. Is detected. As a result, the analog meter reading device 1 can significantly reduce the power consumption as compared with the device using the image sensor.

In particular, the analog meter reading device 1 requires less time for the light detection itself than the device using the image sensor, so that the measurement frequency of the indicator needle meter 100 is not high (for example, in a few hours). In the case of one time), the power consumption can be suppressed from a fraction to a tenth.

In the present embodiment, the analog meter reading device 1 transmits the indicated value to the server device 200, but instead of the indicated value, the analog meter reading device 1 transmits the position information of the indicating needle 101 represented by the index number of the photodiode 13. May be good. In this case, since the server device 200 may convert the position information of the indicator needle 101 into the indicated value by referring to the conversion table created by itself, the server device 200 transmits the conversion table created by itself to the analog meter reading device 1. You can save time and effort.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The same parts as those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted.

FIG. 11 is a diagram showing a cross-sectional shape of the photodiode 13 according to the second embodiment. In the second embodiment, the lens 13a is formed on the light receiving surface of the photodiode 13. The light sensitive region of the photodiode 13 changes depending on the presence or absence of the lens 13a. Here, the light-sensitive region refers to a spatial region in which the presence of a point light source can be detected by the photodiode 13. The range in the depth direction and the range in the width direction of the light sensitive region are limited according to the optical characteristics of the lens 13a.

FIG. 12 (A) is a schematic view showing a light sensitive region A1 of the photodiode 13 when the photodiode 13 does not have a lens, and FIG. 12 (B) is a schematic diagram showing the light sensitivity when the lens 13a is formed on the photodiode 13. It is a schematic diagram which shows the region A2.

In the case of FIG. 12A, the light-sensitive region A1 of the photodiode 13 includes not only the indicator needle 101 but also the scale plate 102. Therefore, when the scale number or the manufacturer's logo mark is displayed on the scale plate 102, the photodiode 13 obtains an output signal influenced by those displayed objects. Specifically, the level of the output signal of the photodiode 13 is lowered as if the indicator needle 101 actually exists even though the indicator needle 101 does not exist.

In the case of FIG. 12 (B), the light-sensitive region A2 of the photodiode 13 is limited in the depth direction as compared with the light-sensitive region A1 of FIG. 12 (A) due to the influence of the optical characteristics of the lens 13a. That is, the light-sensitive region A2 includes the indicator needle 101 or its vicinity in the depth direction, but does not include the scale plate 102. Therefore, even if the scale plate 102 has a display such as a scale number or a manufacturer's logo mark or does not have such a display, the output signal of the photodiode 13 is not affected.

Therefore, when the photodiode 13 detects the indicator needle 101, the photodiode 13 obtains a low-level output signal (a signal corresponding to black) as in the first embodiment. Further, when the indicator needle 101 is not detected, the photodiode 13 is not affected by the presence or absence of a display object such as a scale number on the scale plate 102 or a manufacturer's logo mark, and corresponds to a high level output signal (corresponding to white). Signal). That is, as in the first embodiment, it can be seen that the indicator needle 101 is at a position where the output signal corresponds to the low-level photodiode 13.

Therefore, as shown in FIG. 12B, when the depth direction of the light-sensitive region is limited by the lens 13a, the photodiode 13 has a display object such as a scale number or a manufacturer's logo mark on the scale plate 102. Even in some cases, it is possible to obtain an output signal of an appropriate level depending only on the presence of the indicator needle 101.

FIG. 13 is a diagram showing light sensitive regions A11 to A15 and A21 to A25 having different diameters. When the photodiode 13 does not have the lens 13a (FIG. 12 (A)), the adjacent light-sensitive regions A11 to A15 partially overlap each other as shown in FIG. Therefore, when the indicator needle 101 is present at the position shown in FIG. 13, it is detected in the two light sensitive regions A12 and A13.

When the photodiode 13 has a lens 13a (FIG. 13B), the diameters of the light-sensitive regions A21 to A25 are smaller than the diameters of the light-sensitive regions A11 to A15. Therefore, the adjacent light-sensitive regions A21 to A25 do not overlap each other and are in contact with each other. Therefore, when the indicator needle 101 is present at the position shown in FIG. 13, it is detected only in one light sensitive region A22. That is, by limiting the diameter (width direction) of the light-sensitive regions, it is possible to suppress the overlap of adjacent light-sensitive regions, and the detection accuracy of the position information of the indicator needle 101 is improved.

As a result, the analog meter reading device 1 according to the second embodiment can detect the depth direction of the light-sensitive region even when the scale number or the manufacturer's logo mark is displayed on the scale plate 102 of the indicator needle meter 100. By limiting, the position information of the indicator needle 101 of the indicator needle meter 100 can be detected with high accuracy without being affected by those displayed objects. Further, the analog meter reading device 1 can detect the position information of the indicator needle 101 with higher accuracy by limiting the width direction of the light sensitive region.

In the second embodiment, as shown in FIG. 13, adjacent light sensitive regions A21 to A25 are in contact with each other without overlapping, thereby improving the detection accuracy of the position information of the indicator needle 101. Such an example. It is not limited to. For example, as in the second embodiment, the diameter of the light-sensitive regions may be reduced, and as in the first embodiment, adjacent light-sensitive regions may overlap each other. At this time, the position information of the indicator needle 101 is detected by the "indicator needle position information detection method 1 (weighted average)" or "indicator needle position information detection method 2 (maximum likelihood method)" of the first embodiment. It is possible.

As described above, by reducing the diameter (width direction) of the light-sensitive regions and allowing the adjacent light-sensitive regions to overlap each other, the number of photodiodes 13 that can be mounted per unit length is dramatically increased. Can be increased to. As a result, the detection accuracy of the position information of the instruction needle 101 and the calculation accuracy of the instruction value can be further improved.

[Third and Fourth Embodiments]
Next, the third and fourth embodiments of the present invention will be described. The same parts as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

In the third embodiment, an analog meter (hereinafter, referred to as “float meter”) in which a float made of a non-transparent member moves inside a tapered tube made of a transparent member is a reading target.

FIG. 14 is a diagram showing a state in which the reading unit 10a of the analog meter reading device 1 according to the third embodiment is attached to the float meter 150. 15 (A) is a plan view of the reading unit 10a, and FIG. 15 (B) is a side view. The analog meter reading device of the present embodiment includes a reading unit 10a instead of the reading unit 10 shown in FIG.

As shown in FIG. 14, the float meter 150 is a float that is inserted into a tapered tube 151 that is a transparent tube with a scale displayed and a tapered tube 151 in which a liquid is injected and can move in the tapered tube 151. It is equipped with 152. The scale at the position of the float 152 is the indicated value.

As shown in FIG. 15, the reading unit 10a includes a storage case 12p formed in a long shape, a plurality of photodiodes 13 linearly arranged in the storage case 12p, and a plurality of photos in the storage case 12a. A plurality of LED elements 14 arranged linearly along the diode 13 are provided.

The storage case 12p includes a storage bottom 12p1 which is a long plate member on which a plurality of photodiodes 13 and LED elements 14 are installed, and an outer peripheral wall 12p2 formed on the outer peripheral portion of the storage bottom 12p1. The height of the outer peripheral wall 12p2 is larger than the height from the arrangement surface of the photodiode 13 and the LED element 14. Therefore, when the reading unit 10 is attached to the tapered tube 151, the end portion of the outer peripheral wall 12p2 is adhered to the tapered tube 151. That is, the photodiode 13 and the LED element 14 do not have to come into contact with the tapered tube 151, and damage due to contact is avoided.

The LED element 14 irradiates the float meter 150 with light. The photodiode 13 obtains an output signal according to the reflected light depending on the position of the float 152 of the float meter 150. The control unit 30 calculates the indicated value of the float meter 150 based on the output signal from the reading unit 10a in the same manner as in the first embodiment.

FIG. 16 is a diagram showing a reading unit 10b of the analog meter reading device 1 according to the fourth embodiment. The reading unit 10b separates the light emitting function and the light receiving function of the reading unit 10a shown in FIG. Specifically, the reading unit 10b includes a light receiving unit 10b1 having a plurality of photodiodes arranged linearly, and a light emitting unit 10b2 having a plurality of LED elements arranged linearly.

The light receiving unit 10b1 houses a plurality of photodiodes 14 in a storage case configured in the same manner as the storage case 12p of FIG. The light emitting unit 10b2 also houses a plurality of photodiodes 13 in a storage case configured in the same manner as the storage case 12p of FIG. Therefore, as will be described later, even when the light receiving unit 10b1 and the light emitting unit 10b2 are attached to the tapered tube 151, the photodiode 13 and the LED element 14 do not have to come into contact with the tapered tube 151, and damage due to contact is avoided. Will be done.

The light receiving unit 10b1 and the light emitting unit 10b2 are mounted on both side surfaces of the float meter so as to sandwich the tapered tube 151 of the float meter 150. The light receiving unit 10b1 is irradiated from the light emitting unit 10b2 to obtain an output signal corresponding to the transmitted light of the tapered tube 151. The control unit 30 calculates the indicated value of the float meter 150 based on the output signal from the light receiving unit 10b1 in the same manner as in the first embodiment.

As described above, the analog meter reading device 1 according to the third and fourth embodiments uses the reading unit 10a or the reading unit 10b in which the photodiode 13 and the LED element 14 are linearly arranged for the float meter 150. As a result, the indicated value of the float meter 150 can be calculated.

1 Analog meter readers 10, 10a, 10b Reading unit 13 Photodiode 14 LED element 30 Control unit 100 Indicator needle Meter 101 Indicator needle 102 Scale plate 103 Cover glass 150 Float meter 151 Taper tube 152 Float

The analog meter reading device according to the present invention includes a scale plate and an indicator needle that indicates an indicated value of the scale plate and rotates with respect to a predetermined rotation center on a plane at a predetermined distance from the display surface side of the scale plate. An analog meter reading device that reads the indicated value of an indicator needle meter having a transparent member that covers the display surface side of the scale plate so as to include the indicator needle, and is a plurality of light emitting elements and a plurality of light receiving elements. A reading unit having an outer peripheral wall formed along the outer circumference and including the plurality of light emitting elements and a storage member for accommodating the plurality of light receiving elements, wherein the plurality of light receiving elements are the said members of the reading unit. The plurality of light emitting elements are arranged in an arc shape in the storage member, the plurality of light emitting elements are arranged along the outside or the inside of the plurality of light receiving elements in the storage member of the reading unit , and the reading unit is placed on the transparent member. In a state of being mounted near the center of rotation of the indicator needle, the plurality of light receiving elements detect light emitted from the plurality of light emitting elements and reflected by the indicator needle or the scale plate of the indicator needle meter. A state in which the reading unit has one or more markers at predetermined relative positions with respect to the plurality of light receiving elements on the surface opposite to the mounting surface of the reading unit, and the reading unit is mounted on the transparent member. A calculation unit that calculates the rotation center of the indicator needle of the indicator needle meter based on the brightness component of the scale region of the indicator needle meter in the photographed image of the indicator needle meter obtained when the indicator needle meter is photographed. Based on the rotation center calculated by the calculation unit, the scale region extracted from the captured image, and the position information of the marker based on the captured image, each of the light receiving elements of the plurality of light receiving elements A conversion table creation unit that creates the conversion table that describes the correspondence between the index number assigned based on the arrangement position and the scale value on the scale plate, and the conversion table created by the conversion table creation unit. A conversion table storage unit to be stored, an index number detection unit that detects a substantial index number corresponding to the presence position of the indicator needle based on the detection result of at least one of the plurality of light receiving elements, and the index. It is provided with an instruction value calculation unit that calculates the instruction value based on the substantial index number detected by the number detection unit, the conversion table stored in the conversion table storage unit, and the conversion table. ..

Claims (8)

A reading unit comprising a plurality of light emitting elements regularly arranged along a predetermined direction and a plurality of light receiving elements regularly arranged along a predetermined direction or the plurality of light emitting elements.
An analog meter reading device that reads the analog meter with the reading unit mounted at a predetermined position on a transparent member of the analog meter. The analog meter includes a scale plate, an indicator needle that rotates with a predetermined rotation center on a plane at a predetermined distance from the display surface side of the scale plate, and a display surface of the scale plate so as to include the indicator needle. An indicator needle meter having the transparent member covering the side.
The reading unit is formed in a circular shape and further has a first storage unit for accommodating the plurality of light receiving elements and the plurality of light emitting elements, and the plurality of light receiving elements are the first storage units of the reading unit. The plurality of light emitting elements are arranged in an arc shape along the inside of the outer circumference in the member, and the plurality of light emitting elements are arranged in an arc shape along the outside or inside of the plurality of light receiving elements in the first storage member of the reading unit. ,
With the reading unit mounted near the center of rotation of the indicator needle on the transparent member, the plurality of light receiving elements are the indicator needle or the scale of the indicator needle meter emitted from the plurality of light emitting elements. The analog meter reading device according to claim 1, which detects light reflected on a slope. The analog meter device according to claim 2, wherein the first storage member has a hole formed in the center thereof. One or more markers are arranged at predetermined relative positions with respect to the plurality of light receiving elements on the surface opposite to the mounting surface of the reading unit, and the indicator needle meter is mounted on the transparent member. A calculation unit that calculates the rotation center of the indicator needle of the indicator needle meter based on the brightness component of the scale region of the indicator needle meter in the captured image of the indicator needle meter obtained when the image is taken.
The second aspect of the present invention further comprises a determination unit for determining the validity of the mounting position of the reading unit based on the rotation center calculated by the calculation unit and the position information of the marker based on the captured image. Analog meter device. The analog meter has a tapered tube which is a transparent member in which a liquid is injected and a scale is displayed, and a float which is a non-transparent member inserted into the tapered tube and indicates the surface of the liquid. It is a float meter
The reading unit is formed in a long shape and further includes a plurality of light receiving elements and a second storage member for accommodating the plurality of light emitting elements, and the plurality of light receiving elements are housed in the second storage member. The plurality of light emitting elements are linearly arranged, and the plurality of light emitting elements are linearly arranged along the arrangement of the plurality of light receiving elements in the second storage member.
With the reading unit mounted on the float meter and along the movement range of the float, the plurality of light receiving elements detect light emitted from the plurality of light emitting elements and reflected by the float. The analog meter reading device according to claim 1. The analog meter has a tapered tube which is a transparent member in which a liquid is injected and a scale is displayed, and a float which is a non-transparent member inserted into the tapered tube and indicates the surface of the liquid. It is a float meter
The reading unit further includes a third storage member formed in an elongated shape and accommodating the plurality of light receiving elements, and a fourth accommodating member formed in an elongated shape and accommodating the plurality of light emitting elements. The plurality of light receiving elements are linearly arranged in the third storage member, and the plurality of light emitting elements are linearly arranged in the fourth storage member.
The third storage member is on the float meter and is mounted along the movement range of the float, and the fourth storage member is on the float meter and faces the third storage member. The analog meter reading device according to claim 1, wherein the plurality of light receiving elements detect light emitted from the plurality of light emitting elements and transmitted through the float meter in a state of being mounted at a position. The analog meter reading device according to any one of claims 2 to 4, wherein a lens member is formed on the light receiving surface of each of the plurality of light receiving elements. The analog meter reading device according to claim 7, wherein the light sensitive region of the light receiving element is limited to at least one of the depth direction and the lateral direction by the lens member.