WO2021085081A1 - Approximate data generation device and approximate data generation method - Google Patents

Abstract

An approximate data generation device (1) according to the present invention is provided with: a break point setting unit (12) that, in an approximation section R designated along the X coordinate axis of the data represented by a graph on an XY coordinate plane, generates approximate data of the data, and sets first and last break points at points where the Y value in the data in the approximate section R is in a predetermined value range respectively from an end point (x₀, y₀) and the other end point (x_n+1, y_n+1) having an X value greater than the X value of the end point (x₀, y₀), which are both ends of the approximation section R; and an approximate value calculation unit (40) that, on the basis of comparison between an optional X value in the approximation section R and the X values of the first and last break points, calculates an approximate value of the Y value of the data corresponding to the optional X value. This can provide an approximate data generation feature that enables further reduction in a memory use amount and in a calculation amount in performing polygonal line approximation.

Description

Approximate data creation device and approximate data creation method

The present invention relates to an approximate data creation device and an approximate data creation method, and particularly to a technique for approximating measurement data.

Conventionally, in data polygonal line approximation, interpolation processing such as interpolation between polygonal points and straight line approximation has often been performed. Therefore, there is a need for a break point that allows the interpolation process to cover the entire approximation range of the data to be calculated for the break line approximation (see, for example, Patent Document 1). Therefore, for example, as shown in FIG. 12, it is necessary to provide a break point at the boundary of the approximate range or outside the approximate range (break points “0”, “n + 1” (n = 0, n = 0, in FIG. 12). 1, ...)).

According to the conventional polygonal line approximation, even if the value of the polygonal point “0” and the value of the polygonal point “1” shown in FIG. 12 are the same within the allowable error range, the approximation interval R which is the approximation range is set. It was necessary to set a break point at the end point of the approximation interval R so that it could be covered by interpolation processing such as interpolation and straight line approximation. Similarly, even if the value of the break point “n + 1” and the value of the break point “n” in FIG. 12 are the same value within the tolerance range, the approximate interval R of the approximate range can be covered by the interpolation process. Therefore, it is necessary to set a break point at the other end point of the approximate interval R as well. Therefore, when the conventional polygonal line approximation is adopted, the number of polygonal points cannot be reduced, and it is difficult to reduce the memory usage amount and the calculation amount.

Japanese Unexamined Patent Publication No. 11-072691

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an approximation data creation technique capable of further reducing the amount of memory used and the amount of calculation when performing polygonal line approximation.

In order to solve the above-mentioned problems, the approximate data creation device according to the present invention creates approximate data of the data in a designated approximate interval along the X coordinate axis of the data represented by the graph on the XY coordinate plane. The Y value of the data in the approximate section from each of the first end point which is both ends of the approximate section and the second end point which has an X value larger than the X value of the first end point in the approximate data creation device. A fold point setting unit configured to set a first fold point and a second fold point at a point within the range of preset values, an arbitrary X value in the approximate section, and the first fold. It is provided with an approximate value calculation unit configured to calculate an approximate value of the Y value of the data corresponding to the arbitrary X value based on the comparison between the point and the X value of the second break point.

Further, in the approximate data creation device according to the present invention, the break point setting unit sets a discrete third break point in the data in the approximate section between the first break point and the second break point. The approximate value calculation unit sets the approximate value, and the arbitrary X value is among the break points including the first break point, the second break point, and the third break point set by the break point setting unit. , When not sandwiched between the folding points adjacent to each other in the X coordinate axis direction, the Y value of the nearest bending point is calculated as an approximate value of the Y value corresponding to the arbitrary X value. 1 Approximate portion may be provided.

Further, in the approximate data creation device according to the present invention, in the approximate value calculation unit, the arbitrary X value is set by the break point setting unit, the first break point, the second break point, and the first break point. Of the fold points including the three fold points, when they are sandwiched between the fold points adjacent to each other in the X coordinate axis direction, the fold points adjacent to each other are linearly interpolated and calculated, corresponding to the arbitrary X value. A second approximation unit configured to obtain the Y value to be used as an approximation value may be provided.

Further, the approximate data creation device according to the present invention further includes an approximate curve generation unit configured to generate an approximate curve of the approximate section based on the approximate value calculated by the approximate value calculation unit. May be good.

Further, the approximate data creation device according to the present invention may further include a display device configured to display the approximate curve of the approximate section generated by the approximate curve generation unit.

In order to solve the above-mentioned problems, the approximate data creation method according to the present invention creates approximate data of the data in a designated approximate interval along the X coordinate axis of the data represented by the graph on the XY coordinate plane. A method for creating approximate data executed by an approximate data creation device, wherein the break point setting unit has an X value larger than the X values of the first end points at both ends of the approximate section and the first end point. From each of the above, the first step of setting the first break point and the second break point at the point where the Y value of the data in the approximate section is within the range of the preset value, and the approximate value calculation unit Based on the comparison between the arbitrary X value in the approximate section and the X value of the first break point and the second break point, an approximate value of the Y value of the data corresponding to the arbitrary X value is calculated. It includes a second step.

According to the present invention, the first break point and the first break point and the first point from each of the first end point and the second end point, which are both ends of the approximate section, are the points where the Y value of the data in the approximate section is within the preset value range. Two break points are set, and the approximate value of the Y value of the data corresponding to the arbitrary X value is calculated based on the comparison between the arbitrary X value in the approximate interval and the X value of the first break point and the second break point. Since the calculation is performed, the memory usage amount and the calculation amount when performing the polygonal line approximation can be further reduced.

FIG. 1 is a block diagram showing a configuration of an approximate data creation device according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the operation of the approximate data creation device according to the present embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of the approximate data creation device according to the present embodiment. FIG. 4 is a flowchart illustrating the operation of the approximate data creation device according to the present embodiment. FIG. 5 is a diagram for explaining a break point setting process according to the present embodiment. FIG. 6 is a diagram for explaining an approximate value calculation process according to the present embodiment. FIG. 7 is a diagram for explaining the operation of the approximate data creation device according to the present embodiment. FIG. 8 is a diagram for explaining the operation of the approximate data creation device according to the present embodiment. FIG. 9 is a diagram for explaining the operation of the approximate data creation device according to the present embodiment. FIG. 10 is a diagram for explaining the operation of the approximate data creation device according to the present embodiment. FIG. 11 is a diagram for explaining the operation of the approximate data creation device according to the present embodiment. FIG. 12 is a diagram for explaining a conventional polygonal line approximation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 11.

[Functional block of approximate data creation device]
The approximation data creating device 1 approximates a non-linear data measured externally to a polygonal line within a set approximation range. The approximation data creation device 1 according to the present embodiment is an extension of the above-mentioned conventional polygonal line approximation, and for the data in the approximation range not surrounded by the polygonal points, the approximate data using the value of the nearest polygonal point is used. One of its features is to create.

As shown in FIG. 1, the approximation data creation device 1 includes, for example, a data acquisition unit 10, a section designation unit 11, a break point setting unit 12, a determination unit 13, a first approximation unit 14, a second approximation unit 15, and an approximation curve. A generation unit 16, a storage unit 17, and a presentation unit 18 are provided. The determination unit 13, the first approximation unit 14, and the second approximation unit 15 constitute an approximation value calculation unit 40.

The data acquisition unit 10 acquires the data to be approximated. For example, the data acquisition unit 10 can acquire non-linear process data such as data measured by an external sensor or device via the communication network NW. Alternatively, the data acquisition unit 10 can read the data of the approximation target stored in the storage unit 17 in advance. FIG. 2 shows an example of the data acquired by the data acquisition unit 10 (curve y = f (x) of the “approximate object” in FIG. 2).

In the present embodiment, the data is bivariate data consisting of (x, y), and can be represented by a two-dimensional planar point set of XY as shown in FIG. For example, if the data is time-series data of a measured value of a physical quantity, x and y are a quantity representing time and a measured value of the physical quantity, respectively.

The section designation unit 11 designates an approximate section in the data acquired by the data acquisition unit 10. In this embodiment, this approximation interval is defined with respect to the X axis of the XY plane. For example, in FIG. 2, the approximate interval R [x ₀ , x _{n + 1} ] is specified. The lower limit of the approximate interval R is x ₀ , the upper limit is _{indicated by x n + 1} , and the data is continuous within the approximate interval R. The section designation unit 11 can designate the approximate section R according to the operation input received from the outside by the input device 107 described later.

The break point setting unit 12 sets the break point in the approximate section R designated by the section designation unit 11. The break point setting unit 12 has an end point (first end point) (x ₀ , y _{0 ) of data at both ends of the approximate interval R [x 0} , x _{n + 1} ] and the other end point having a _{value x n + 1} larger than the _{value x 0.} From each of (second end point) (x _{n + 1} , y _{n + 1} ), the first break point (first break point) (1st break point) is set to a point where the y value of the data in the approximate interval R is within the preset value range. x ₁ , y ₁ ) and the last break point (second break point) (x _n , y _n ) are set. The first break point and the last break point are break points having break points adjacent only in the inner direction of the approximate section R provided on the boundary line of the approximate section R or on both ends in the approximate section R.

The break point setting unit 12 _{acquires, for example, a section having an arbitrary y value y 1} and a y value within an error range. The break point setting unit 12 can set the end point of the approximate section R in the section _{that is not the end point (x 0} , y ₀ ) as the first break point (x ₁ , y ₁ ).

_{Similarly, the break point setting unit 12 acquires, for example, a section having y n} as a certain y value and a y value within the error range, and is not _{the end point (x n + 1} , y _{n + 1} ) of the approximate section R in the section. The end point of can be set as the last break point (x _n , y _n).

As shown in the example of FIG. 2, the break point setting unit 12 does not set break points at both ends (x ₀ , y ₀ ) and (x _{n + 1} , y _{n + 1} ) of the approximated section R. That is, the y _value from the end point (x ₀ , y 0) of the approximate interval R to the first break point (x ₁ , y ₁ ) is within the error range. Further, the y value from the other end point (x _{n + 1} , y _{n + 1} ) of the approximate interval R to the last break point (x _n , y _n ) is also within the error range.

Further, the break point setting unit 12 has a break point (third break point) (third break point) discrete with respect to the data between the _{first break point (x 1} , y ₁ ) and the last break point (x _n , y _n). Set x _i , y _i ) (i = 2, ..., n-1). The break point setting unit 12 sets, for example, a plurality of break points between the first break point (x ₁ , y ₁ ) and the last break point (x _n , y _n ). The break point setting unit 12 uses a known method such as the Ramer-Douglas-Pucker algorithm to make a break point between the first break point (x ₁ , y ₁ ) and the last break point (x _n , y _n ). Can be provided. The break points set by the break point setting unit 12 are stored in the storage unit 17. The break point setting unit 12 can also set one break point between the first break point (x ₁ , y ₁ ) and the last break point (x _n , y _n ).

For example, as shown in the “break point” in FIG. 2 _{, the first break point (x 1} , y ₁ ) and the last _{break point (x 1, y 1) are included in the approximate interval R [x 0} , x _{n + 1} ] in order to approximate the data to a polygonal line. A plurality of break points are set between the break points (x _n , y _n). As shown in FIG. 2, the break points can be set at equal intervals along the X-axis, for example. Further, the number of break points can be appropriately set according to the characteristics of the data (y = f (x)), the approximation accuracy required in the specified approximation interval R, the memory capacity, and the like.

The approximate value calculation unit 40 compares an arbitrary x value for which an approximate value in the approximate interval R is to be obtained with the x value of the first break point (x ₁ , y ₁ ), and the last break point (x _n ,). Based on the comparison with the x value of y _n ), the approximate value of the y value of the data corresponding to the x value for which the approximate value is to be obtained is calculated.

As shown in FIG. 1, the approximation unit 40 includes a determination unit 13, a first approximation unit 14, and a second approximation unit 15.
The determination unit 13 determines whether or not an arbitrary x value for which an approximate value is to be obtained is smaller than the X coordinate value x _{1 of the first break point (x 1} , y _1). Further, the determination unit 13 determines whether or not the x value for which the approximate value is to be obtained is larger than the X coordinate value x _{n of the last break point (x n} , y _n).

_{The first approximation unit 14 approximates y 1} , which is the y value of the first break point, when the determination unit 13 determines that the x value for which the approximate value is to be obtained _{is smaller than the value x 1 of the first break point.} Returns as a value. _{Further, the first approximation unit 14 is y n,} which is the y value of the last break point when the determination unit 13 determines that the x value for which the approximation value is to be obtained _{is larger than the value x n of the last break point.} Is returned as an approximate value.

That is, when the x value for which the approximate value is to be obtained is not sandwiched between the break points set by the break point setting unit 12 and adjacent to each other on the X-axis, the first approximation unit 14 has a break point setting unit 12. The y value of the nearest break point is used as it is and calculated as an approximate value.

In the second approximation unit 15, when the x value for which the approximation value is to be obtained is sandwiched between the break points set by the break point setting unit 12 that are adjacent to each other on the X axis, the second approximation unit 15 is located between the break points. The adjacent break points are linearly interpolated, the y value corresponding to the x value for which the approximate value is to be obtained is calculated, and the approximate value is obtained. For example, when the x-values for which an approximate value is to be obtained are sandwiched between the x-values of _{adjacent break points (x i} , y _i ) and (x _{i + 1} , y _{i + 1 ) (x i} ≤ x <x _{i + 1} ), the break point " The value obtained by linearly interpolating (or also referred to as "internal division") the y value of "i" and the break point "i + 1" is calculated as an approximate value of the y value.

In the example of FIG. 2, the portion indicated by "linear interpolation" of the approximation interval R is the data portion for which the approximation value is calculated by the second approximation unit 15. Further, both end portions of the approximated section R shown by the “takeover portion” in FIG. 2 are data portions calculated as approximate values by using the y value of the nearest bending point as it is by the first approximated portion 14.

The approximate curve generation unit 16 generates an approximate curve of the approximate interval R based on the approximate value calculated by the first approximate unit 14 and the approximate value calculated by the second approximate unit 15. The generated approximate curve is stored in the storage unit 17.

The storage unit 17 stores the data to be approximated acquired by the data acquisition unit 10. Further, the storage unit 17 stores the information of the break point set by the break point setting unit 12. The storage unit 17 stores the approximate curve of the data generated by the approximate curve generation unit 16.

The presentation unit 18 presents an approximate curve of the data generated by the approximate curve generation unit 16. For example, the presentation unit 18 can display an approximate curve on the display screen of the display device 108 described later. The presentation unit 18 can display, for example, the approximate curve shown in FIG. 2 on the display screen. Alternatively, the presentation unit 18 can send the generated approximate curve to an external arithmetic unit (not shown).

[Hardware configuration of approximate data creation device]
Next, the hardware configuration for realizing the approximate data creation device 1 having the above functions will be described with reference to the block diagram of FIG.

As shown in FIG. 3, the approximate data creation device 1 includes, for example, a processor 102, a main storage device 103, a communication interface 104, an auxiliary storage device 105, an input / output I / O 106, and an input device 107 connected via a bus 101. , And a computer equipped with a display device 108, and a program that controls these hardware resources. The processor 102 is composed of a CPU, a GPU, and the like.

The main storage device 103 stores in advance programs for the processor 102 to perform various controls and calculations. The processor 102 and the main storage device 103 approximate the section designation unit 11, the break point setting unit 12, the determination unit 13, the first approximation unit 14, the second approximation unit 15, the approximation curve generation unit 16, and the like shown in FIG. Each function of the data creation device 1 is realized.

The communication interface 104 is an interface circuit for connecting a network between the approximate data creation device 1 and various external electronic devices. For example, the data acquisition unit 10 can receive data to be analyzed from an external device or terminal device (not shown) via the communication network NW from the communication interface 104.

The auxiliary storage device 105 is composed of a readable and writable storage medium and a drive device for reading and writing various information such as programs and data to the storage medium. A semiconductor memory such as a hard disk or a flash memory can be used as the storage medium in the auxiliary storage device 105.

The auxiliary storage device 105 has a program storage area for storing a program for the approximate data creation device 1 to execute a break point setting process, an approximate process, and an approximate curve creation process. The auxiliary storage device 105 realizes the storage unit 17 described with reference to FIG. Further, for example, it may have a backup area for backing up the above-mentioned data, programs, and the like.

The input / output I / O 106 is composed of I / O terminals that input signals from external devices and output signals to external devices.

The input device 107 is composed of physical keys, a touch panel, and the like, and outputs a signal corresponding to an operation input from the outside.

The display device 108 is composed of a liquid crystal display or the like. The display device 108 realizes the presentation unit 18 described with reference to FIG.

[Approximate data creation method]
Next, the operation of the approximate data creation device 1 having the above-described configuration will be described with reference to the flowcharts of FIGS. 4 to 6.

First, the outline of the approximate data creation method will be described with reference to FIG. As shown in FIG. 4, the data acquisition unit 10 acquires the data of the approximation target represented by the graph on the XY coordinate plane (step S1). The acquired data is stored in the storage unit 17. As the data, for example, non-linear process data measured by a device such as a sensor can be used. Next, the section designation unit 11 designates an approximate section R to be approximated in the acquired data (step S2). Next, the break point setting unit 12 sets the break point of the approximate section R specified in step S2 (step S3).

After that, the approximate value calculation unit 40 calculates the approximate value of the data at an arbitrary x value using the break point of the approximate section R specified in step S2 (step S4). Next, the approximate curve generation unit 16 generates an approximate curve from the approximate value of the approximate interval R calculated by the approximate value calculation unit 40 (step S5). After that, the presentation unit 18 presents the approximate curve generated in step S5. For example, the presentation unit 18 can display the approximate curve shown in FIG. 2 on the display device 108.

[Break point setting process]
Here, the break point setting process (step S3 in FIG. 4) by the break point setting unit 12 will be described with reference to the flowchart of FIG.

First, in the break point setting unit 12, the data value is expressed within the margin of error of _{a certain value y 1 from the end point (x 0} , y ₀ ) on the side where the value in the X coordinate of the approximate section R is small. Acquire the section (step S30). _{Next, the break point setting unit 12 provides the first break point (x 1} , y ₁ ) at the end point other than the end _{point (x 0} , y ₀ ) of the approximate section R in the section acquired in step S30. (Step S31). In the example of FIG. 2, the point indicated by the break point “1” is the first break point set in step S31.

Next, the break point setting unit 12 has a permissible error of a certain value y _{n from the end point (x n + 1} , y _{n + 1} ) on the side where the value in the X coordinate of the approximate section R specified in step S2 is large. The section represented within the range is acquired (step S32). _{Next, the break point setting unit 12 provides the last break point (x n} , y _n ) at the end point other than the end _{point (x n + 1} , y _{n + 1} ) of the approximate section R in the section acquired in step S32 (x n, y n). Step S33). In the example of FIG. 2, the point indicated by the break point “n” is the last break point set in step S33.

Next, the break point setting unit 12 sets a break point in _{the data between the first break point (x 1} , y ₁ ) and the last break point (x _n , y _n ) (step S34). The break point setting unit 12 can provide a break point by using a known method such as the Ramer-Douglas-Pucker algorithm. Further, the break point setting unit 12 can provide a plurality of break points in step S34. The break points set by the break point setting unit 12 are stored in the storage unit 17 (step S35).

Further, in the example of FIG. 7, the first break point "1" is set by the break point setting unit 12. However, since there is no section within the permissible error range from an arbitrary value y _n , a break point is set at _{the end point (x n + 1} , y _{n + 1) of the approximate section R.}

On the other hand, in the example of FIG. 8, the final break point "n" is set by the break point setting unit 12. However, on the other end point (x ₀ , y ₀ ) side of the approximate interval R, there was no section within the permissible error range with _{any y 1 , so the end point (x 0} , y ₀ ) of the approximate interval R was broken. The point is set.

[Approximate value calculation process]
Next, the approximate value calculation process (step S4 in FIG. 4) executed by the approximate value calculation unit 40 will be described with reference to the flowchart of FIG.

First, the approximate value calculation unit 40 reads out the break point recorded in the storage unit 17 (step S40). Next, the approximate value calculation unit 40 acquires the value of the X coordinate in the approximate section R for which the approximate value is to be obtained (step S41). For example, the approximate value calculation unit 40 can acquire an arbitrary x value of the X coordinate received by the input device 107. Alternatively, a preset X-coordinate value can be acquired.

Next, the determination unit 13 determines whether or not the value of the X coordinate for which the approximate value obtained in step S41 is to be obtained _{is smaller than x 1} of the X coordinate of the first break point, and if it is smaller, ( Step S42: YES), the first approximation unit 14 returns the y value of the first break point as an approximation value (step S43).

On the other hand, when the value of the X coordinate for which the determination unit 13 wants to obtain the approximate value obtained in step S41 _{is the same as x n} of the X coordinate of the first break point (step S42: NO, step S44: NO). , The first approximation unit 14 returns the y value of the last break point as an approximation value (step S45).

On the other hand, when the value of the X coordinate for which the determination unit 13 wants to obtain the approximate value obtained in step S41 _{is larger than x 0} of the X coordinate of the first break point (step S42: NO, step S44: YES). ), The second approximation unit 15 uses the X-coordinate value x _i of the break point "i" and the X-coordinate value x _{i + 1 of the} break point "i + 1" to table x as x _i ≤ x <x _{i + 1.} Find the i to be done (step S46).

After that, the second approximation unit 15 returns the value obtained by linearly interpolating (internally dividing) the y values of the break point “i” and the break point “i + 1” as approximate values (step S47). More specifically, the second approximation unit 15 obtains the data between the break points calculated using the following equation (1) as an approximation value.

However, i indicates a break point (i = 0, 1, ...).

FIG. 9 shows a part of the approximated interval R in which the data between the break points is linearly interpolated by the second approximated portion 15.

Further, FIG. 10 shows a part of the approximation section R in which the value of the first break point is used as it is by the first approximation unit 14. The first approximation unit 14 calculates an approximation value of the approximation section R using the following equation (2) based on the value y ₁ of the first break point “1” (x ₁ , y _{1) of the approximation interval R.} ..
y = y ₁ ... (2)

On the other hand, in the example of FIG. 11, the break point "n + 1" is not set on the upper limit side of the approximate section R, and the data of the section along the x-axis outside the break point "n" of the approximate section R is y. The value is inherited as it is.

FIG. 11 shows a part of the approximation section R in which the value of the last break point is used as it is by the first approximation unit 14. The first approximation unit 14 calculates an approximate value of the approximate interval R using the following equation (3) based on the value y _n of the last break point “n” (x _n , y _n).
y = y _n ... (3)

As described above, according to the present embodiment, the number of break points in the designated approximate section can be reduced, so that the memory usage can be reduced, the device can be downsized, and the power consumption can be reduced. Can contribute.

Further, according to the present embodiment, it is possible to reduce the number of break points in the designated approximate section, which can contribute to the reduction of man-hours.

Further, according to the present embodiment, outside the approximate section in which the break point is set, the value of the nearest break point is used as it is, and by inputting a value outside the range, the approximate value by the polygonal line approximation is used. It is possible to avoid an error that makes it unsolicited. Further, since the value of the nearest neighbor break point is used outside the approximate interval, the obtained approximate value is the value of the nearest neighbor break point and is not usually an extremely different value, so that the subsequent calculation process is more appropriate. Can be done.

In the embodiment described, the case where the approximate data creation device 1 includes the data acquisition unit 10, the section designation unit 11, and the break point setting unit 12 has been illustrated, but these configurations are based on the approximate data creation device 1. It may be provided externally. In this case, the data of the approximation target stored in advance in the storage unit 17 of the approximation data creation device 1, the approximation interval specified in the data, and the information about the break point set in the data are read, and the approximation data creation device 1 reads the information. The above-mentioned approximation data creation process is executed.

[Concrete example]
Next, a specific example to which the approximate data creation device 1 according to the above-described embodiment is applied will be described. As described above, the case where the data to be approximated by the approximation data creation device 1 is, for example, non-linear process data has been described. The approximate data creation device 1 can be applied to, for example, the generation of an approximate curve when calculating the flow rate correction coefficient as a function of the Reynolds number in an ultrasonic flow meter. Further, the approximate data creation device 1 can be applied to an integrated calorimeter that calculates the amount of heat using the flow rate measured by such an ultrasonic flow meter.

For example, the flow rate correction coefficient can be theoretically obtained for a flow path having a special shape or surface condition. However, in general, the flow rate correction coefficient is measured for each Reynolds number by an experiment, and this is approximated by a fold line, and at the time of measurement, the flow rate correction coefficient for the Reynolds number is often calculated by this fold line approximation.

When the fluid is flowing as a laminar flow, the flow rate correction coefficient is a constant value regardless of the flow velocity. Generally, when the Reynolds number is about 2000 or less, it is considered to be a laminar flow, so the flow rate correction coefficient becomes a constant value where the flow rate is small (the Reynolds number is small). For example, in the case of a cylindrical flow path, the flow rate correction coefficient at the time of laminar flow is 4/3 (= 1.333 ...).

When the fluid is turbulent, the flow rate correction coefficient changes as a function of the Reynolds number, but when the flow rate increases (the Reynolds number increases), the flow velocity of the entire flow path becomes uniform and the flow rate correction coefficient becomes 1. Get closer. If the measurement range of the flow meter is set up to a large flow rate and it can be regarded as a constant flow rate correction coefficient above a certain Reynolds number in consideration of the accuracy of the flow meter, the flow rate is large (the Reynolds number is large). The flow rate correction coefficient can be a constant value.

When the approximation data creation device 1 according to the present embodiment is applied to the polygonal line approximation of the flow rate correction coefficient, the number of break points can be reduced by one or two depending on the flow rate measurement range of the flow meter.

Although the embodiments of the approximate data creation device and the approximate data creation method of the present invention have been described, the present invention is not limited to the described embodiments and is assumed by those skilled in the art within the scope of the invention described in the claims. It is possible to make various possible modifications.

1 ... Approximate data creation device, 10 ... Data acquisition unit, 11 ... Section designation unit, 12 ... Break point setting unit, 13 ... Judgment unit, 14 ... 1st approximation unit, 15 ... Second approximation unit, 16 ... Approximate curve generation Unit, 17 ... storage unit, 18 ... presentation unit, 101 ... bus, 102 ... processor, 103 ... main storage device, 104 ... communication interface, 105 ... auxiliary storage device, 106 ... input / output I / O, 107 ... input device, 108 ... Display device, NW ... Communication network.

Claims (6)

1. It is an approximation data creation device that creates approximation data of the data in the approximation section specified along the X coordinate axis of the data represented by the graph on the XY coordinate plane.
   A range of preset values for the Y value of the data in the approximated section from each of the first end point which is both ends of the approximated section and the second end point which has an X value larger than the X value of the first end point. A break point setting unit configured to set a first break point and a second break point at a point inside, and a break point setting unit.
   Based on the comparison between the arbitrary X value in the approximate section and the X value of the first break point and the second break point, the approximate value of the Y value of the data corresponding to the arbitrary X value is calculated. An approximate data creation device including an approximate value calculation unit configured as described above.
2. In the approximate data creation device according to claim 1,
   The break point setting unit sets a discrete third break point in the data in the approximate section between the first break point and the second break point.
   In the approximate value calculation unit, the X coordinate axis of the arbitrary X value among the break points including the first break point, the second break point, and the third break point set by the break point setting unit. A first approximation unit configured to calculate the Y value of the nearest break point as an approximation of the Y value corresponding to the arbitrary X value when it is not sandwiched between the break points adjacent to each other in the direction. An approximate data creation device characterized by being equipped with.
3. In the approximate data creation device according to claim 2.
   In the approximate value calculation unit, the X coordinate axis of the break points including the first break point, the second break point, and the third break point whose arbitrary X value is set by the break point setting unit. When sandwiched between fold points adjacent to each other in the direction, the Y value corresponding to the arbitrary X value, which is calculated by linearly interpolating the fold points adjacent to each other, is configured to be obtained as an approximate value. An approximation data creation device including a second approximation unit.
4. In the approximate data creation device according to any one of claims 1 to 3.
   An approximation data creating apparatus, further comprising an approximation curve generation unit configured to generate an approximation curve for the approximation section based on the approximation value calculated by the approximation value calculation unit.
5. In the approximate data creation device according to claim 4,
   An approximate data creation device further comprising a display device configured to display an approximate curve of the approximate section generated by the approximate curve generation unit.
6. An approximation data creation method executed by an approximation data creation device that creates approximation data for the data in a specified approximation interval along the X coordinate axis of the data represented by the graph on the XY coordinate plane.
   From each of the first end point which is both ends of the approximate section and the second end point which has an X value larger than the X value of the first end point, the break point setting unit sets the Y value of the data in the approximate section in advance. The first step of setting the first and second break points at points within the set value range, and
   The approximation value calculation unit compares an arbitrary X value in the approximation section with the X values of the first break point and the second break point, and the Y value of the data corresponding to the arbitrary X value. Approximate data creation method including a second step of calculating an approximate value of.

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