JP2009294180A - Apparatus and technique for moving average calculation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moving average calculation apparatus and moving average calculation technique capable of outputting proper average value corresponding to variation of input value even when noise is contained in input value. <P>SOLUTION: A moving average calculation section 6, which uses m input values from the newest input value (Tn), where m≤n, back to only m to compute sequentially the average values of a plurality of input values (T1 to Tn) input sequentially, computes the difference (¾ΔTn¾) between the newest input value (Tn) and the past input values (either from T1 to Tn-1), and is equipped with a number setting means 62 for setting the number (M) of input value used when the average values are computed, based on a magnitude relation between the difference (¾ΔTn¾) and a threshold value (Th) defined from magnitude of noise (N) containable in input values. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a moving average value calculation apparatus and a moving average value calculation method for sequentially calculating an average value of sequentially input values using the latest input value.

  Conventionally, as a moving average value calculating apparatus, as shown in Patent Document 1, a device that sequentially calculates a time average value with a section s for calculating a time average as s (= β / α) is known. Here, β is a minimum resolution when digitizing a change amount that changes with time, and α is a threshold value of a time average value.

  According to such a moving average value calculation device, for example, since the temperature change rate is obtained based on the moving average value instead of the digital conversion value itself of the temperature detection value, the drop in the change rate is less likely to occur. Even if this occurs, the degree is reduced. Therefore, the degree of digital variation of the change rate is reduced, and the determination accuracy of whether or not the change rate exceeds the threshold value α is improved.

  However, in the conventional moving average value calculation device, for example, in a measurement environment where a stable temperature continues after a rapid temperature rise / fall, such as a heating furnace, it cannot follow a rapid temperature fluctuation and overshoot. It was difficult to detect whether or not

On the other hand, the moving average value calculation apparatus disclosed in Patent Document 2 outputs the detection value as it is without averaging the accumulated detection value for a sudden pressure change in the pressure gauge. According to this moving average value calculating device, even when a sudden pressure change occurs, the detected value is output as it is, so that the output can follow the change.
JP 2000-124806 A Japanese Patent Application Laid-Open No. 11-118651

  However, in the conventional moving average value calculation device, even when the fluctuation of the detected value is due to noise caused by sensor failure or deterioration, or generally generated electric noise (hereinafter referred to as noise), this is output as it is. There is a problem of being done.

  This is contrary to the original purpose of using the moving average, which is to stabilize the output by accumulating the detected values and outputting the average value to avoid the sudden change of the sensor output due to noise. Become.

  In view of the above circumstances, the present invention provides a moving average value calculation apparatus and moving average value calculation capable of outputting an appropriate average value corresponding to a change in an input value even when noise is included in the input value. It aims to provide a method.

  A moving average value calculation apparatus according to a first aspect of the present invention is a moving average value calculation apparatus that sequentially calculates an average value of input values that are sequentially input using the latest input value, the latest input value and a past input value. And a number setting means for setting the number of input values used for calculating the average value according to the magnitude relationship between the difference and a predetermined threshold value.

  According to the moving average value calculation apparatus of the first invention, the number used for calculating the moving average value is set based on the difference between the latest input value and the past input value. Therefore, when the change of the latest input value is large, for example, the number of input values can be decreased, and the output of the average value can be easily followed by this change. On the other hand, when the change of the latest input value is small, for example, by increasing the number of input values and reducing the influence of noise, a stable average value can be output.

  Here, the number used to calculate the moving average value is set according to the magnitude relationship between the difference and the threshold value determined from the magnitude of noise. Therefore, for example, by setting the threshold value to be larger than the noise level, it becomes possible to make the output of the average value follow only the change of the input value exceeding the threshold value. Thereby, it is possible to reliably reduce the influence of noise and output an appropriate average value corresponding to the change of the input value.

  In addition to the threshold value determined based on the above-described noise magnitude, a threshold value determined based on an SN ratio or a threshold value determined in consideration of resolution / accuracy / reproducibility can be considered. In any case, a value that can reduce the influence of noise and output an appropriate average value corresponding to the change of the input value may be set as the threshold value.

  The past input value used when calculating the difference may be an input value immediately before the latest input value (one cycle before), or may be a value other than the input value immediately before the latest input value. For example, the input value immediately before the previous input value (input value input two cycles before the latest input value) or the input value immediately before that (input value input three cycles before the latest input value) ) May be used. Thereby, even when the input value immediately before the latest input value (one cycle before) changes due to noise, the influence can be relatively reduced by keeping a certain interval.

  The moving average value calculating apparatus according to a second invention is the moving average value calculating apparatus according to the first invention, wherein the number setting means has a difference greater than the first threshold value with respect to the first threshold value which is the predetermined threshold value. In this case, the number of the input values is set to a first number, and when the number is equal to or less than the first threshold, the number is set to a second number larger than the first number.

  According to the moving average value calculation apparatus of the second aspect of the invention, when the first threshold value is set to a value larger than the noise level, for example, the difference is a change in the input value exceeding the first threshold value. In addition, the average value is calculated using a first number that is small in number used for calculating the moving average value. Therefore, it is possible to make the output of the average value follow the change of the input value without making the output of the average value follow the noise component. On the other hand, when the difference is a change in the input value below the first threshold, the change in the input value may include a noise component. In this case, a stable average value is output by reducing the influence of noise by calculating the average value with the second number that is larger than the first number to be used for calculating the moving average value. be able to. Thereby, even when noise is included in the input value, an appropriate average value corresponding to the change in the input value can be output.

  A moving average value calculating apparatus according to a third invention is the moving average value calculating apparatus according to the second invention, wherein the number setting means has the difference with respect to a second threshold set to a value larger than the first threshold. The first number is set to 1 when it is larger than the second threshold value.

  According to the moving average value calculating apparatus of the third invention, a second threshold value larger than the first threshold value is set, and the moving average value is calculated when the difference is a change in the input value exceeding the second threshold value. For this purpose, the input value is output as it is, assuming that the number used for this is 1. Thereby, especially when the change of the input value is significant, it is possible to reliably follow the change of the input value while avoiding the output following the noise component.

  The moving average value calculation apparatus according to a fourth aspect of the present invention is the moving average value calculation apparatus according to any one of the first to third aspects, wherein the difference is a difference between the latest input value and an average value of past input values. It is characterized by that.

  According to the moving average value calculation apparatus of the fourth invention, by using the average value of the past input values as the past input values used when calculating the difference, it does not depend on the past input values that can be individually changed by noise. The difference can be calculated. For this reason, it is possible to reduce the influence of noise, reliably capture changes in the input value, and output an appropriate average value corresponding to this.

  According to a fifth aspect of the present invention, there is provided a fluorescent temperature sensor comprising: a light emitting element that projects light onto a fluorescent material; a light receiving element that receives fluorescence emitted from the fluorescent material; and a signal processing unit that generates a temperature detection value from an output signal of the light receiving element. A moving average value calculation unit that outputs the moving average value with the temperature detection value as an input is configured by the moving average value calculation device according to any one of claims 1 to 4. It is characterized by.

  According to the fifth aspect of the present invention, the fluorescent temperature sensor calculates and outputs a moving average value for the temperature detection value acquired at a constant processing cycle. It is suitable as a target to apply.

  A moving average value calculation method according to a sixth aspect of the present invention is a moving average value calculation method for sequentially calculating an average value of input values sequentially input using the latest input value, wherein the latest input value and a past input value are calculated. And a number setting process for setting the number of input values used when calculating the average value according to the magnitude relationship between the difference and a predetermined threshold value, and a number set by the number setting process. An average value calculation process for calculating these average values is sequentially executed using the input value.

  According to the moving average value calculation method of the sixth invention, the number used to calculate the moving average value is set based on the difference between the latest input value and the past input value, and the set number of input values is used. The average value is calculated sequentially. Therefore, when the change in the latest input value is large, the number of input values is decreased to make it easier to follow the output of the average value, or when the change in the latest input value is small, A stable output can be performed by increasing the number of input values and reducing the influence of noise.

  Furthermore, since the number used to calculate the moving average value is set according to the magnitude relationship between the difference and the threshold value determined from the noise level, by setting the threshold value to be larger than the noise level, for example, It becomes possible to easily follow the output of the average value only for the change of the input value exceeding the threshold value. As described above, various setting methods for the threshold value can be considered.

  As described above, even when the input value includes noise, it is possible to calculate and output an appropriate average value corresponding to the change of the input value.

  As an embodiment of the present invention, an example in which a moving average value calculation device is used in a moving average value calculation unit of a fluorescence temperature sensor will be described with reference to FIGS.

  First, the overall configuration of the fluorescence temperature sensor of the present embodiment will be described with reference to FIG. The fluorescent temperature sensor receives a fluorescent material 1 that exhibits different fluorescent characteristics depending on temperature, an LED 2 that projects light onto the fluorescent material 1, a drive unit 3 that outputs an electrical signal that drives the LED 2, and fluorescence emitted by the fluorescent material 1. Photodiode 4, a signal processing unit 5 that calculates a corresponding temperature detection value from an output signal from the photodiode 4, and a data that represents the temperature by calculating a moving average value of the temperature detection value connected to the signal processing unit 5 As a moving average value calculating unit 6 (corresponding to the moving average value calculating device of the present invention).

  The fluorescence temperature sensor includes an optical fiber 7 that projects light onto the fluorescent material 1 and receives fluorescence from the fluorescent material 1. The other end of the optical fiber 7 is branched to form a light projecting optical fiber 7 a that transmits the light from the LED 2 to the fluorescent material 1 and a light receiving optical fiber 7 b that transmits the fluorescence of the fluorescent material 1 to the photodiode 4. Yes.

  The fluorescent material 1 is disposed so as to face the core portion of the optical fiber 7 in the temperature measurement unit 1 a provided so as to cover one end of the optical fiber 7.

  The LED 2 is a light emitting diode disposed in the LED module 2a and having, for example, a blue wavelength as an emission color. The LED module 2a has a connector part 2b to which the light projecting optical fiber 7a is connected, and the light projecting optical fiber 7a connected via the connector part 2b faces the light emitting part of the LED 2.

  The drive unit 3 includes a control circuit that applies a pulse current that defines the magnitude of the drive current necessary for light emission of the LED 2 and the light emission time to the LED 2 at a constant processing cycle. Thereby, for example, the driving unit 3 corresponds to the fluorescent material 1 to the LED 2 with a pulse current having a predetermined magnitude that sets the light emission time of the LED 2 in one measurement to any time between 1 ms and 500 ms. Apply.

  The photodiode 4 is disposed in the photodiode module 4a and measures the amount of light (luminance) of the irradiated light. The photodiode module 4 a has a connector portion 4 b connected to the light receiving optical fiber 7 b, and the light receiving optical fiber 7 b connected via the connector portion 4 b faces the light receiving portion of the photodiode 4.

  The signal processing unit 5 measures the fluorescence attenuation characteristics of the fluorescent material 1 measured by the photodiode 4, particularly the fluorescence relaxation time, in the processing cycle (processing cycle corresponding to the light projection processing cycle of the LED 2). Specifically, the signal processing unit 5 calculates the temperature of the temperature measurement environment in which the fluorescent material 1 exists from a relational expression (including a data table and a map) between the fluorescent relaxation time and the fluorescent material 1 provided in advance. Output.

  The moving average value calculating unit 6 includes a memory holding unit 61, a number setting unit 62, and an average value calculating unit 63, and sequentially calculates the average value of the temperature detection values sequentially input from the signal processing unit 5 in the processing cycle. Calculate and output.

  The memory holding means 61 is configured by an internal memory (not shown) or the like, and stores and holds a predetermined number of temperature detection values sequentially input from the signal processing unit 5 from the latest one.

  The number setting means 62 reads the temperature detection value stored and held in the memory holding means 61, calculates the difference between the latest temperature detection value and the past temperature detection value, and determines the difference between the difference and a preset threshold value. The number of temperature detection values used for calculating the average value is set according to the relationship. Here, the threshold value is determined from the magnitude of noise that can be included in the temperature detection value (see STEP 21 in FIG. 2 and STEP 22 in FIG. 3).

  The average value calculation means 63 sequentially executes a process of calculating these average values using the number of temperature detection values set by the number setting means 62 including the latest temperature detection values.

  In the present embodiment, each of the processing units 3, 5, and 6 is provided in the controller 10 configured by a microcomputer or the like. The processing units 3, 5, and 6 constituting the controller 10 are configured by hardware such as a CPU, a ROM, and a RAM, and the processing units 3, 5, and 6 may be configured by common hardware. In addition, some or all of these processing units 3, 5, and 6 may be configured by different hardware.

  Next, a process for calculating the moving average value by the moving average value calculation unit 6 will be described with reference to the flowchart shown in FIG.

  First, the moving average value calculation unit 6 sequentially acquires the latest temperature detection value (Tn) output from the signal processing unit 5 for each processing cycle (STEP 10). Here, the subscript n (n: natural number) of the temperature detection value (T) represents the order of the temperature detection values acquired from the signal processing unit 5, and the smaller the n is, the earlier the processing cycle is. For example, the temperature detection value before one processing cycle is Tn-1.

  Then, the moving average value calculation unit 6 newly stores and holds the acquired temperature detection value (Tn) in the storage holding means 61 (STEP 11).

  Next, the number setting unit 62 of the moving average value calculation unit 6 reads the temperature detection values (T1 to Tn) stored and held in the storage holding unit 61, and the latest temperature detection value (Tn) and immediately before (1 process). The absolute value (| ΔTn |) of the difference ΔTn = (Tn) − (Tn−1) from the temperature detection value (Tn−1) before the cycle is calculated (STEP 12).

  Next, the number setting means 62 determines whether or not the absolute value of the difference (| ΔTn |) is larger than the first threshold value (Th1) (STEP 21). Here, the first threshold (Th1) is set to a value larger than the magnitude of noise (N) that may be included in the temperature detection value. In this way, by setting the first threshold value (Th1), it is possible to capture the change in the temperature detection value itself regardless of the change due to the noise component among the change in the temperature detection value.

  Then, when the absolute value (| ΔTn |) of the difference is larger than the first threshold value (Th1) (YES in STEP 21), the number setting unit 62 sets the number of temperature detection values used for calculating the average value. The first number (M1) is set (STEP 31). On the other hand, when the absolute value (| ΔTn |) of the difference is equal to or less than the first threshold value (Th1) (NO in STEP 21), the number setting unit 62 sets the number of temperature detection values used for calculating the average value. The second number (M2) is set (STEP 32). Here, the first number (M1) and the second number (M2) have a relationship of M1 << M2. The second number (M2) is a normal number (for example, 500) used when calculating the moving average value in the fluorescence temperature sensor. On the other hand, the first number (M1) is about 25% of the second number (M2) (for example, 125).

  In this way, when a change in the temperature detection value larger than the noise level occurs, the average value is calculated for the noise component by setting the number used for calculating the average value to the first number (M1) which is smaller than usual. The output of the average value can be made to easily follow the change of the temperature detection value while avoiding the follow-up of the output. On the other hand, for the change in the temperature detection value due to noise, the average value is calculated with the normal second number (M2) larger than the first number (M1), thereby reducing the influence of noise and stabilizing. Temperature detection can be performed.

  Next, the average value calculation means 63 of the moving average value calculation unit 6 calculates the average value using the number of temperature detection values set in STEP 31 or STEP 32 including the latest temperature detection value (Tn) (STEP 40). Then, the moving average value calculation unit 6 outputs the calculated average value as an output value (temperature detection value) of the temperature sensor (STEP 41).

  The above is a series of processes of the moving average value calculation unit 6, and the moving average value calculation unit 6 sequentially executes these series of processes in the processing cycle corresponding to the light projection processing cycle of the LED 2, thereby moving average. Calculate the value. In the above embodiment, the process of setting the number of use in STEP 31 and 32 based on the determination result of STEP 21 corresponds to the number setting process of the present invention, and the process of STEP 40 is the average value calculation process of the present invention. Equivalent to.

  Next, a modified example of the processing of the flowchart shown in FIG. 2 will be described with reference to the flowchart shown in FIG. Note that the processing of the flowchart of FIG. 3 is a modification of part of the processing of the flowchart of FIG. 2, and therefore, the same processing as in FIG.

  In this embodiment, when the absolute value of the difference (| ΔTn |) is larger than the first threshold value (Th1) (YES in STEP 21), the number setting means 62 determines that the absolute value of the difference is the second threshold value (Th2). ) Is determined (STEP 22). Here, the second threshold (Th2) is set to a value larger than the first threshold (Th1). In this way, by setting the second threshold value (Th2), even when the change in the temperature detection value is significant, the change can be captured.

  If the absolute value of the difference (| ΔTn |) is larger than the second threshold value (Th2) (YES in STEP 22), the number setting unit 62 sets the number of temperature detection values used when calculating the average value. 1, the latest temperature detection value (Tn) is output as it is as the output value of the temperature sensor (STEP 42). As a result, the output can reliably follow the change in the input value, particularly when the change in the temperature detection value is significant.

  On the other hand, when the absolute value of the difference (| ΔTn |) is equal to or smaller than the second threshold value (Th2) (NO in STEP 22), the number setting unit 62 sets the number of temperature detection values used for calculating the average value. As the first number (M1) (STEP 31), the average value is calculated from the temperature detection values of the first number (M1) (STEP 40) and output (STEP 41).

  The above is the example of a change of the process by the moving average value calculation part 6. FIG. In the above embodiment, the process of setting the number of use in STEP 32 based on the determination result of STEP 21 and the process of setting the number of use in STEP 31 and 42 based on the determination result of STEP 22 are the number setting process of the present invention. Equivalent to.

  As described above, the fluorescent temperature sensor of this embodiment can sequentially output an appropriate average value corresponding to a change in the temperature detection value even when the temperature detection value includes noise.

  In the present embodiment, when the first and second threshold values (Th1, Th2) are set for the absolute value (| ΔTn |) of the difference and the threshold values are exceeded, the number of used is set to the normal second number (M2). ) Is set to a small first number (M1) or the like. However, the present invention is not limited to this, and the number used may be increased if it is within the threshold.

  In the present embodiment, the first and second thresholds (Th1, Th2) are provided and the number of use (M1, M2) is set. However, the present invention is not limited to this. A threshold value may be provided to decrease or increase the number in steps. Thereby, it is possible to sequentially calculate the average value with the optimum number of use according to the change of the temperature detection value.

  Furthermore, in this embodiment, the difference (| ΔTn |) is calculated as the difference between the latest temperature detection value (Tn) and the temperature degree detection value (Tn−1) immediately before (one processing cycle). Not limited to this, instead of the temperature detection value (Tn-1) before one processing cycle, the temperature detection value before two processing cycles (Tn-2) and the temperature detection value before three processing cycles (Tn-3) May be used. As a result, even when the temperature detection value (Tn-1) before one processing cycle changes due to noise, the influence can be relatively reduced by providing a certain interval.

  Further, an average value may be used instead of the past value (Tn-1, Tn-2) of the temperature detection value. As a result, the difference can be calculated regardless of the past temperature detection value that can be individually changed by noise, the influence of noise is reduced, the change of the temperature detection value is reliably captured, and an appropriate response corresponding to this is obtained. An average value can be output, and thus a stable temperature output can be realized.

  As described above, the embodiment in which the temperature detection value of the fluorescent temperature sensor is used as the input value has been described. However, the present invention is not limited to this, and can be applied to the calculation of the average of the inputs that are sequentially input.

The whole block diagram of the fluorescence temperature sensor of this embodiment. The flowchart which shows the process which calculates the moving average value in a moving average value calculation part. Explanatory drawing which shows the example of a change of the flowchart shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fluorescent material, 2 ... LED, 3 ... Drive part, 4 ... Photodiode, 5 ... Signal processing part, 6 ... Moving average value calculation part (moving average value calculation apparatus), 7 ... Optical fiber, 10 ... Controller, 61 ... memory holding means, 62 ... number setting means, 63 ... average value calculating means.

Claims (6)

A moving average value calculating device that sequentially calculates an average value of input values sequentially input using the latest input value,
A number setting unit configured to calculate a difference between the latest input value and a past input value, and to set the number of input values used when calculating the average value according to a magnitude relationship between the difference and a predetermined threshold value; The moving average value calculation apparatus characterized by the above-mentioned. The moving average value calculation apparatus according to claim 1,
The number setting means sets the number of the input values to the first number when the difference is greater than the first threshold which is the predetermined threshold, and is equal to or less than the first threshold. If it is, the moving average value calculating device is characterized in that the number is set to a second number larger than the first number. In the moving average value calculation apparatus according to claim 2,
The number setting means sets the first number to 1 when the difference is larger than the second threshold with respect to the second threshold set to a value larger than the first threshold. A moving average value calculation device. The moving average value calculating apparatus according to any one of claims 1 to 3,
The moving average value calculation apparatus according to claim 1, wherein the difference is a difference between the latest input value and an average value of past input values. In a fluorescence temperature sensor including a light emitting element that projects light onto a fluorescent material, a light receiving element that receives fluorescence emitted from the fluorescent material, and a signal processing unit that generates a temperature detection value from an output signal of the light receiving element,
5. A fluorescent temperature characterized in that a moving average value calculation unit that receives the temperature detection value as an input and outputs the moving average value is constituted by the moving average value calculation device according to any one of claims 1 to 4. Sensor. A moving average value calculation method for sequentially calculating an average value of input values sequentially input using the latest input value,
A number setting process for calculating a difference between the latest input value and a past input value, and setting a number of input values used when calculating the average value according to a magnitude relationship between the difference and a predetermined threshold;
A moving average value calculation method characterized by sequentially executing an average value calculation process for calculating an average value of the number of input values set by the number setting process.

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