JP2010185851A - Measuring device using infrared sensor and calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring device for automatically correcting offset of an infrared sensor by solving the problem that any conventional technology needs constituents other than the infrared sensor, makes it difficult to miniaturize a measuring system including the infrared sensor in the measuring device and to reduce cost for them, and makes it difficult to separate objects desired to be detected generating a signal component when the objects already exist and an environment variation not desired to be detected generating the signal component thereafter. <P>SOLUTION: Output signals of an infrared sensor unit 1 are measured with a sensor output measurement unit 2. Necessary sensor output out of measured sensor outputs is selected with a sensor output selection unit 3 to store the sensor output to a sensor output storing unit 4. The measuring device 100 automatically corrects offset of the infrared sensor 1 with a sensor offset correction unit 5 on the basis of data of the sensor output storing unit 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a measuring apparatus using an infrared sensor and a calibration method thereof.

  2. Description of the Related Art Conventionally, a technique for detecting the presence / absence, position, and movement of an object using an infrared sensor is known. In particular, a technique for detecting a human body as an object is applied to many application fields such as a toilet, lighting control, and an input device. In order to apply this technique, it is necessary to separate an object that is the object of infrared sensor measurement, such as the above-described human body, and an object that is not desired to be an object of infrared sensor measurement. Typical examples of objects that are not intended for the latter include direct sunlight (sunlight), incandescent lamps, and other environmental fluctuations. For example, in a situation where the human body and the incandescent lamp cannot be separated, there may occur a case where the lighting of the incandescent lamp is erroneously recognized as an approach or presence of the human body.

  As a method for preventing such erroneous recognition of the infrared sensor due to environmental fluctuations, for example, conventional techniques such as those disclosed in Patent Document 1 and Patent Document 2 have been proposed. Patent Document 1 discloses a technique for preventing erroneous recognition by providing a reference infrared sensor (thermoelectric conversion device) separately from an infrared sensor for detection (generally a thermoelectric conversion device). Patent Document 2 discloses a technique for preventing erroneous recognition by providing a known optical signal (infrared signal) to an infrared sensor in advance, or by providing a shutter that blocks light (infrared light). .

JP 2000-298062 A JP 2004-333132 A

However, each of the prior arts of Patent Document 1 and Patent Document 2 has a problem that it requires components other than the infrared sensor as described above. Specifically, Patent Document 1 requires a reference infrared sensor, and Patent Document 2 requires a shutter. When components such as electronic parts and structures other than the infrared sensor are required as described above, it is difficult to reduce the size and cost of the measurement system including the infrared sensor in the measurement apparatus.
Moreover, even if the method disclosed in Patent Document 1 is used, the above-described erroneous recognition cannot be prevented essentially. This is because the reference infrared sensor cannot detect these even if it is a human body or an incandescent lamp, and naturally cannot separate them.
Even using the technique disclosed in Patent Document 2, it is generally impossible to separate the human body from the incandescent lamp, for example. This is because, as described above, it is necessary to make a known optical signal incident on the infrared sensor in advance. In other words, it can be separated from the optical signal intended by the user, but cannot be separated from the optical signal due to environmental fluctuations not intended by the user.

The first object of the present invention is to use only an infrared sensor as a physical component to separate an object that is desired to be detected like a human body from an environmental change that is not desired to be detected like an incandescent lamp or direct sunlight. There is to do.
Further, the second object of the present invention is to use only an infrared sensor as in the first object, even when an object to be detected such as a human body already exists and the effective signal component is not zero. Then, a new object to be detected that generates a signal component is discriminated from an environmental change that is not to be detected such as an incandescent lamp or direct sunlight that generates a signal component thereafter.

In order to achieve the above object, the present invention provides an infrared sensor, a measuring unit for measuring an output value of the infrared sensor, and an infrared sensor output measured by the measuring unit. A selection unit for selecting a plurality of infrared sensor data from the value; a storage unit for storing the infrared sensor data selected by the selection unit; and an offset of the infrared sensor based on the infrared sensor data stored by the storage unit And a first variation calculation unit for calculating variations in the infrared sensor data based on the infrared sensor data stored by the storage unit, and the first variation calculation. It is determined whether the variation of the infrared sensor data calculated by the means is within the first predetermined range. Stored in the first predetermined determination means, second determination means for determining whether at least one of the infrared sensor data stored in the storage means is within a second predetermined range, and stored in the storage means. Second variation calculating means for calculating the variation of the infrared sensor data based on the infrared sensor data, and whether the variation of the infrared sensor data calculated by the second variation calculating means is within a third predetermined range. A third determination unit that determines whether or not, a change time calculation unit that calculates a change time of the infrared sensor data based on the infrared sensor data stored by the storage unit, and a calculation by the change time calculation unit Fourth determination means for determining whether or not the change time of the infrared sensor data is within a fourth predetermined range; An estimation unit that estimates an offset of the infrared sensor when all the determination results of the determination unit, the second determination unit, the third determination unit, and the fourth determination unit are determined to be true; It is a measuring device using an infrared sensor characterized by comprising an updating means for updating the offset of the infrared sensor based on the result.
According to a second aspect of the present invention, in the measurement apparatus according to the first aspect, the selection unit is a unit that selects a plurality of infrared sensor data within a predetermined time nearest to the output value of the infrared sensor measured by the measurement unit. It is characterized by being.

  According to a third aspect of the present invention, in the measurement apparatus according to the first aspect, the first variation calculating means calculates the difference between the maximum value of the infrared sensor data stored by the storage means and the minimum value of the same data. It is a means.

  The invention according to claim 4 is the measuring apparatus according to claim 1, wherein the first variation calculating means is means for calculating as a standard deviation or variance of infrared sensor data stored by the storing means. To do.

  According to a fifth aspect of the present invention, in the measurement apparatus according to the first, third, or fourth aspect, the first variation calculating means includes recent infrared sensor data from the infrared sensor data stored by the storage means. It includes recent data selection means for selecting a plurality of infrared sensor data, and calculates variations in the infrared sensor data selected by the latest data selection means.

  According to a sixth aspect of the present invention, in the measurement apparatus of the first aspect, the first determination unit determines that the calculation result obtained by the first variation calculation unit is equal to or less than a predetermined threshold value. It is a means to do.

  According to a seventh aspect of the present invention, in the measurement apparatus according to the first aspect, the second determination means further includes a representative value calculation means for further calculating a representative value of the infrared sensor data calculated by the first variation calculation means, Representative value difference calculation means for calculating a difference from the representative value calculated by the representative value calculation means from the infrared sensor data stored by the storage means, wherein the second determination means is the representative value difference calculation It is characterized in that it is determined to be true when at least one of the calculation results obtained by the means is greater than or equal to a predetermined threshold value or less than or equal to a predetermined threshold value.

  The invention according to claim 8 is the measuring apparatus according to claim 7, wherein the representative value calculating means calculates the average value of the infrared sensor data calculated by the first variation calculating means.

  According to a ninth aspect of the present invention, in the measurement apparatus according to the first aspect, the second variation calculation means calculates the difference between the maximum value of the infrared sensor data stored by the storage means and the minimum value of the same data. It is characterized by being.

  The invention according to claim 10 is the measuring apparatus according to claim 1, wherein the second variation calculating means is means for calculating as a standard deviation or variance of infrared sensor data stored by the storing means. To do.

  According to an eleventh aspect of the present invention, in the measurement apparatus according to any one of the first, seventh, ninth, or tenth aspects, the second variation calculating means is configured to obtain the second determining means from the infrared sensor data stored by the storing means. Including post-determination data selection means for selecting a plurality of infrared sensor data including infrared sensor data determined to be true, and calculating variations in the infrared sensor data selected by the post-determination data selection means. Features.

  According to a twelfth aspect of the present invention, in the measurement apparatus according to the first aspect, the third determination unit determines true when the calculation result obtained by the second variation calculation unit is equal to or less than a predetermined threshold value. It is a means to do.

  According to a thirteenth aspect of the present invention, in the measurement apparatus of the first or twelfth aspect, the calculating means for calculating the second variation calculating means a predetermined number of times and the third determining means are determined by the second variation calculating means. The present invention is characterized in that the means is determined to be false when all the calculation results calculated a predetermined number of times are equal to or greater than a predetermined threshold value.

  According to a fourteenth aspect of the present invention, in the measurement apparatus according to the first aspect, the change time calculating unit is configured to change the infrared sensor data from the time when the infrared sensor data is within the third predetermined range. The sensor data is calculated as the time until the time when the sensor data falls within the first predetermined range.

  The invention according to claim 15 is the measuring apparatus according to claim 1, wherein the change time calculation means is configured such that the infrared sensor data is from the latest time when the infrared sensor data is within the third predetermined range. The time is calculated as the time until the farthest time when the infrared sensor data is within the first predetermined range.

  According to a sixteenth aspect of the present invention, in the measurement apparatus according to the first aspect, the fourth determination unit is configured such that the change time calculated by the change time calculation unit is equal to or less than a predetermined threshold value. It is a means to judge to be true.

  According to a seventeenth aspect of the present invention, in the measurement apparatus according to the first aspect, the estimating means is a predetermined infrared sensor offset of an infrared sensor from infrared sensor data at a time falling within the second predetermined range. And a signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means, wherein the estimation means includes the first determination means, The signal difference calculation stored by the signal difference calculation result storage means from the infrared sensor data at the determination time when all the determination results of the second determination means, the third determination means and the fourth determination means are determined to be true. The estimation means uses a difference from the result as an offset estimation value, and the updating means is an updating means for updating the offset value to the offset estimation value. And features.

  According to an eighteenth aspect of the present invention, in the measuring apparatus according to the first aspect, the estimating means is a predetermined infrared sensor offset of an infrared sensor from infrared sensor data at a time falling within the third predetermined range. And a signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means, wherein the estimation means includes the first determination means, The signal difference calculation stored by the signal difference calculation result storage means from the infrared sensor data at the determination time when all the determination results of the second determination means, the third determination means and the fourth determination means are determined to be true. The estimation means uses a difference from the result as an offset estimation value, and the updating means is an updating means for updating the offset value to the offset estimation value. And features.

  According to a nineteenth aspect of the present invention, in the measuring apparatus according to the first aspect, the estimating means is a predetermined infrared sensor offset of the infrared sensor from infrared sensor data at a time falling within the second predetermined range. And a signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means, wherein the estimation means includes the first determination means, From the calculation result calculated based on a predetermined number of infrared sensor data after the determination time when all the determination results of the second determination unit, the third determination unit, and the fourth determination unit are determined to be true, The difference calculation result storage means stores a difference from the signal difference calculation result stored in the estimation means, and the updating means sets the offset value to the off-state. Characterized in that it is a updating means for updating the Tsu preparative estimate.

  According to a twentieth aspect of the present invention, in the measuring apparatus according to the first aspect, the estimating unit is configured to offset an infrared sensor of a predetermined infrared sensor from infrared sensor data at a time falling within the third predetermined range. And a signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means, wherein the estimation means includes the first determination means, From the calculation result calculated based on a predetermined number of infrared sensor data after the determination time when all the determination results of the second determination unit, the third determination unit, and the fourth determination unit are determined to be true, The difference calculation result storage means stores a difference from the signal difference calculation result stored in the estimation means, and the updating means sets the offset value to the off-state. Characterized in that it is a updating means for updating the Tsu preparative estimate.

  According to a twenty-first aspect of the present invention, in the measurement apparatus of the first aspect, threshold setting means for presetting a predetermined threshold, a threshold set by the threshold setting means, Comparing means for comparing the measured value of the infrared sensor, and infrared sensor detection determining means for determining whether or not the infrared sensor has detected based on the result of the comparing means.

  The invention according to claim 22 is a measurement step of measuring an output value of the infrared sensor, a selection step of selecting a plurality of infrared sensor data from the infrared sensor output value measured by the measurement step, and a selection by the selection step A storing step for storing the infrared sensor data, and a correcting step for correcting an offset of the infrared sensor based on the infrared sensor data stored by the storing step, wherein the correcting step is stored by the storing step. The first variation calculation step for calculating the variation of the infrared sensor data based on the obtained infrared sensor data, and the variation of the infrared sensor data calculated by the first variation calculation step are within the first predetermined range. The first judgment step for judging whether or not A second determination step for determining whether at least one of the infrared sensor data stored in the storage step is within a second predetermined range; and the infrared sensor data stored in the storage step And determining whether or not the variation of the infrared sensor data calculated by the second variation calculation step and the variation of the infrared sensor data calculated by the second variation calculation step are within a third predetermined range. Based on the infrared sensor data stored in the storing step, a change time calculating step for calculating the change time of the infrared sensor data, and the infrared sensor data calculated in the change time calculating step. Determine whether the change time is within the fourth predetermined range 4 when the determination results of the determination step, the first determination step, the second determination step, the third determination step, and the fourth determination step are all true, the offset of the infrared sensor is estimated. A measuring apparatus calibration method using an infrared sensor, comprising: an estimating step; and an updating step for updating an offset of the infrared sensor based on a result of the estimating step.

  The invention according to claim 23 is the method according to claim 22, wherein the selecting step selects a plurality of infrared sensor data within a predetermined time nearest to the infrared sensor output value measured by the measuring step. And

  According to a twenty-fourth aspect of the present invention, in the method of the twenty-second aspect, the first variation calculating step calculates a difference between the maximum value of the infrared sensor data stored by the storing step and the minimum value of the data. It is characterized by.

  According to a twenty-fifth aspect of the present invention, in the method of the twenty-second aspect, the first variation calculating step is calculated as a standard deviation or variance of the infrared sensor data stored by the storing step.

According to a twenty-sixth aspect of the present invention, in the method according to any one of the twenty-second, twenty-fourth, or twenty-fifth aspects, the first variation calculating step includes a plurality of recent infrared sensor data from the infrared sensor data stored in the storing step. A latest data selection step for selecting the infrared sensor data, and the variation of the infrared sensor data selected by the latest data selection step is calculated.
According to a twenty-seventh aspect of the present invention, in the method of the twenty-second aspect, the first determination step determines true when the calculation result obtained by the first variation calculation step is less than or equal to a predetermined threshold value. It is characterized by that.

  According to a twenty-eighth aspect of the present invention, in the method of the twenty-second aspect, the second determining step further includes a representative value calculating step of further calculating a representative value of infrared sensor data calculated in the first variation calculating step, and the storage. A representative value difference calculating step for calculating a difference from the representative value calculated in the representative value calculating step from the infrared sensor data stored in the step, wherein the second determining step is the representative value difference calculating step. Of the calculation results obtained by the above, it is determined that the condition is true when at least one of the conditions is equal to or greater than a predetermined threshold value or equal to or less than a predetermined threshold value.

  A twenty-ninth aspect of the invention is characterized in that, in the method of the twenty-eighth aspect, the representative value calculating step is calculated as an average value of the infrared sensor data calculated in the first variation calculating step.

  According to a thirty-third aspect of the present invention, in the method of the twenty-second aspect, the second variation calculating step calculates a difference between the maximum value of the infrared sensor data stored by the storing step and the minimum value of the same data. Features.

  The invention described in claim 31 is the method of claim 22, wherein the second variation calculating step calculates as a standard deviation or variance of the infrared sensor data stored by the storing step.

  According to a thirty-second aspect of the present invention, in the method of any one of the twenty-second, twenty-eight, thirty-first, or thirty-first aspects, the second variation calculating step includes: Including a post-determination data selection step of selecting a plurality of infrared sensor data including infrared sensor data determined to be true, and calculating a variation of the infrared sensor data selected in the post-determination data selection step. And

  According to a thirty-third aspect of the present invention, in the method of the twenty-second aspect, the third determination step determines true when the calculation result obtained by the second variation calculation step is less than or equal to a predetermined threshold value. It is characterized by that.

  According to a thirty-fourth aspect of the present invention, in the method of the twenty-second or thirty-third aspect, the calculation step of calculating the second variation calculation step a predetermined number of times and the third determination step are predetermined by the second variation calculation step. It is characterized in that it is determined to be false when all the calculation results calculated by the number of times are equal to or greater than a predetermined threshold value.

  The invention according to claim 35 is the method according to claim 22, wherein in the change time calculating step, the infrared sensor data starts from the time when the infrared sensor data falls within the third predetermined range. The time until the time when the data falls within the first predetermined range is calculated.

  According to a thirty-sixth aspect of the present invention, in the method of the twenty-second aspect, the change time calculating step includes the step of calculating the infrared sensor data from the most recent time when the infrared sensor data is within the third predetermined range. The time is calculated as the time until the farthest time when the infrared sensor data is within the first predetermined range.

  The invention of claim 37 is the method of claim 22, wherein the fourth determination step is performed when the change time calculated by the change time calculation step is equal to or less than a predetermined threshold value. It is determined to be true.

  According to a thirty-eighth aspect of the present invention, in the method of the twenty-second aspect, the estimating step includes a step of determining an infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the second predetermined range. And a signal difference calculation result storing step for storing a signal difference calculation result obtained by the signal difference calculation step, wherein the estimation step includes the first determination step, The signal difference calculation result stored by the signal difference calculation result storage step from the infrared sensor data at the determination time when all the determination results of the second determination step, the third determination step and the fourth determination step are determined to be true. The update step uses an offset value as a pre-set value. Characterized in that an update step of updating the offset estimate.

  According to a thirty-ninth aspect of the present invention, in the method of the twenty-second aspect, the estimating step includes: determining a predetermined infrared sensor offset of an infrared sensor from infrared sensor data at a time falling within the third predetermined range; And a signal difference calculation result storing step for storing a signal difference calculation result obtained by the signal difference calculation step, wherein the estimation step includes the first determination step, The signal difference calculation result stored by the signal difference calculation result storage step from the infrared sensor data at the determination time when all the determination results of the second determination step, the third determination step and the fourth determination step are determined to be true. The update step uses an offset value as a pre-set value. Characterized in that an update step of updating the offset estimate.

  According to a 40th aspect of the present invention, in the method of the 22nd aspect, the estimating step includes a predetermined infrared sensor offset of an infrared sensor from infrared sensor data at a time falling within the second predetermined range. And a signal difference calculation result storing step for storing a signal difference calculation result obtained by the signal difference calculation step, wherein the estimation step includes the first determination step, From the calculation result calculated based on a predetermined number of infrared sensor data after the determination time when all the determination results of the second determination step, the third determination step, and the fourth determination step are determined to be true, the signal difference This is an estimation step in which the difference from the signal difference calculation result stored in the calculation result storage step is the offset estimated value. The update step is characterized by an update step of updating the offset value in the offset estimate.

  According to a 41st aspect of the present invention, in the method of the 22nd aspect, the estimating step includes a predetermined infrared sensor offset of an infrared sensor based on infrared sensor data at a time falling within the third predetermined range. And a signal difference calculation result storing step for storing a signal difference calculation result obtained by the signal difference calculation step, wherein the estimation step includes the first determination step, From the calculation result calculated based on a predetermined number of infrared sensor data after the determination time when all the determination results of the second determination step, the third determination step, and the fourth determination step are determined to be true, the signal difference This is an estimation step in which the difference from the signal difference calculation result stored in the calculation result storage step is the offset estimated value. The update step is characterized by an update step of updating the offset value in the offset estimate.

  The invention of claim 42 is the method of claim 22, wherein a threshold value setting step for presetting a predetermined threshold value, a threshold value set by the threshold value setting step, and a current infrared ray The method further comprises a comparison step of comparing the sensor measurement value and an infrared sensor detection determination step of determining whether or not the infrared sensor is detected based on a result of the comparison step.

  As described above, according to the apparatus and method of the present invention having the above-described configuration, an environment change such as an incandescent lamp or sunlight that an infrared sensor essentially detects, and a user like a human body. The presence / absence, position, and movement of an object to be detected can be distinguished. This separation is all performed based only on the measurement data of the infrared sensor. The present invention can be implemented by adding to existing infrared sensor signal processing and application software. Therefore, an electronic component other than the infrared sensor or an article such as a structure is not required, and a measuring system such as a measuring device can be greatly reduced in size and cost can be reduced.

  The present invention automatically corrects the offset of the infrared sensor. This automatic correction is executed based on the measurement data of the infrared sensor as described above, and does not require a special operation or the like from the user. Therefore, the accuracy of sensor measurement can be improved without impairing user convenience.

  Furthermore, by applying the configuration of the present invention, the measurement accuracy of the infrared sensor is dramatically improved by separating the environmental change and the object to be detected. As a result, the application range of the infrared sensor other than the measuring device can be greatly expanded as compared with the prior art. For example, it can be applied to new uses such as mobile phones and electronic games.

It is the block diagram which showed the structure of the measuring device which concerns on this invention. It is the block diagram which showed the structure of the principal part of the measuring device which concerns on this invention in detail. It is a figure explaining embodiment of this invention, and is a figure showing the example of the time dependence of the measured value at the time of an incandescent lamp lighting. It is a figure explaining embodiment of this invention, and is a figure showing the example of the time dependence of the measured value at the time of a human body approach. It is a figure explaining embodiment of this invention, and is the figure showing the example of the time dependence of the sensor output measurement value when there was an incandescent lamp lighting after a human body approach first on a time series. It is the figure of the flowchart which showed the process sequence performed by the measuring device of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention can be applied to any type of apparatus that uses an infrared sensor, but will be described in detail below by taking a measurement apparatus as an example of a typical embodiment.

  First, the outline of the configuration of the measurement apparatus of the present invention will be described with reference to FIGS. 1 and 2. Next, using FIG. 3 to FIG. 5, the phenomenon handled by the measuring apparatus or method of the present invention will be described while paying attention to the time-series change of the output of the infrared sensor. Finally, using FIG. 6, the technical means specific to the measurement apparatus of the present invention and the processing procedure for executing the method of the present invention will be described using output data obtained from the actual output of the infrared sensor. This processing procedure includes an output data processing step group and a determination step group based on a determination condition. Each step described in FIG. 6 will be described in association with a time-series change in the output of the infrared sensor shown in FIG.

  FIG. 1 is a block diagram showing a configuration of a measuring apparatus according to the present invention. The measuring device 100 of the present invention includes an infrared sensor 1. The infrared sensor used in the present invention is a passive sensor that can detect an object without having a light emitting portion. However, the present invention does not depend on the detection principle, and the gist of the present invention can be applied to other types of infrared sensors as they are or after being modified. Further, the present invention can be similarly applied to a differential output type infrared sensor called a pyroelectric sensor.

  The infrared sensor 1 is connected to a sensor output measuring unit 2 that measures its output. In general, since the output signal of the infrared sensor 1 alone is small, the output signal is electrically amplified using an electronic device such as an operational amplifier. If necessary, the amplified electrical signal is converted into digital data by an AD (Analog to Digital) conversion circuit.

  The sensor output measured by the sensor output measuring unit 2 is connected to the sensor output selecting unit 3, and necessary data is selected from the sensor output measuring unit 2. The sensor output data selected by the sensor output selection unit 3 is stored in the sensor output storage unit 4. Further, the output data stored in the sensor output storage unit 4 is given to the sensor offset correction unit 5 that updates the sensor offset unique to the present invention. A specific method of output selection in the sensor output selection unit 3 and a specific method of output storage (and output discarding) in the sensor output storage unit 4 will be described in detail below together with a specific calculation method.

FIG. 2 is a block diagram showing the measurement apparatus shown in FIG. 1 together with the detailed configuration of the sensor offset correction unit 5. The sensor offset correction unit 5 includes a sensor data first variation calculation unit 5-1, a sensor data first determination unit 5-2, a sensor data second determination unit 5-3, a sensor data second variation calculation unit 5-4, and a sensor. It comprises a third data determination unit 5-5, a sensor data change time calculation unit 5-6, a fourth sensor data determination unit 5-7, a sensor offset estimation unit 5-8, and a sensor offset update unit 5-9.
As described above, the first object of the present invention is to discriminate between an object that is the object of infrared sensor measurement and an object that is not desired to be the object of infrared sensor measurement. First, the difference between the output characteristics of a target object for infrared sensor measurement and the output characteristics of an object that is not desired to be the target of infrared sensor measurement will be described. Thereafter, based on the difference in output characteristics, specific calculation methods and determination methods of the sensor output selection unit 3, the sensor output storage unit 4, and the sensor offset correction unit 5 will be described in detail.

[Difference in Infrared Sensor Output Characteristics]: FIGS. 3 and 4 are diagrams for explaining the difference between the two output characteristics described above. In both FIG. 3 and FIG. 4, the horizontal axis indicates the time, and the vertical axis indicates the sensor output of the sensor output measuring unit 2. Furthermore, the solid line in each figure has shown the example of the actual output value of the sensor output measurement part 2. FIG. FIG. 3 shows a temporal change in the sensor output value when the incandescent lamp is turned on as a representative example of an object that is not desired to be measured by the infrared sensor. On the other hand, FIG. 4 shows a time change of the sensor output value when a human body (palm or the like) approaches as a representative example of the target object for the infrared sensor measurement.
First, the situation shown in FIG. 3 will be described in detail. It is assumed that the output value of the sensor output measuring unit 2 is adjusted to the sensor offset iof at time t0. As the adjusted iof value, as described later, an offset value corrected and updated according to the present invention may be used, or an offset value stored and held in the manufacturing process may be used. It is assumed that the incandescent lamp is turned on at time t2 (i) and is kept on. In this case, the output value of the sensor output measuring unit rises in a short time and then takes a substantially constant value.

The above situation is further quantitatively shown using the symbols shown in FIG. The output value of the sensor output measuring unit 2 starts increasing at time t2 (i) and ends increasing at time t3 (i). Thereafter, an output value that is substantially constant in time is continued until time t4 (i). Here, the time during which the output value is rising is Δt (icdl), the increase in the output value is Δir (icdl), and the variation in the output value after the output value is rising is irpp (icdl).
Next, the situation shown in FIG. 4 will be described in detail. As in FIG. 3, it is assumed that the output value of the sensor output measuring unit 2 is adjusted to the sensor offset iof at time t0. It is assumed that the human body starts approaching at time t2 (h), keeps approaching until time t3 (h), and remains stationary after time t3 (h). In this case, the output value of the sensor output measuring unit rises over a certain period of time, and thereafter takes a substantially constant value. Hereinafter, the above-described situation will be shown more quantitatively using the symbols shown in FIG.

The output value of the sensor output measuring unit 2 starts increasing at time t2 (h) and ends increasing at time t3 (h). Thereafter, a substantially constant output value is continued until time t4 (h). As described with reference to FIG. 3, Δt (hand) is a time during which the output value is rising, Δir (hand) is the amount by which the output value is rising, and irpp (hand) is the variation in the output value after the output value is rising. ).
Under these circumstances described with reference to FIGS. 3 and 4, the output characteristics of the infrared sensor have the following properties (1) and (2) for each parameter defined as described above. I know that.
Δir (icdl)> 0, Δir (hand)> 0 (1) Equation Δt (icdl) <Δt (hand) (2) Equation Further, irppth3 is set as a predetermined positive threshold (irppth3> 0). In many cases, the following equation (3) holds.
irpp (icdl) <irppth3, irpp (icdl) <irppth3
(3) Formula

First, equation (1) indicates that the sensor output of the infrared sensor has increased more than the sensor offset iof. In an actual measurement system, the sensor offset is not completely zero, and noise is superimposed on the sensor output. Therefore, by setting a threshold value Δirthp (= irthp−irof) in advance and determining that both Δir (icdl) and Δir (hand) are larger than Δirthp, either the lighting of the incandescent lamp or the approach of the human body is performed. Detect what happened.
Equation (2) indicates that the time taken for the infrared sensor output to rise at the moment when the incandescent lamp is lit is shorter (smaller) than the time taken for the infrared sensor output to rise at the moment when the human body approaches. ing. Incandescent lamps light up almost instantly from the human sense, but the approach of the human body never ends in an instant. That is, when the incandescent lamp is turned on, the time for the sensor output of the infrared sensor to change is shorter than when the human body is approaching. Accordingly, the change time of the sensor output is measured and calculated, and a threshold value (Δtth) is determined in advance, and it is determined whether or not this change time is smaller than the threshold value Δtth. It becomes possible to sort out whether or not the lighting of has occurred or the approach of the human body has occurred.
Here, a supplementary explanation will be given regarding equation (2). As is clear from equation (2), time is selected as a parameter that appears in the inequality for the purpose of distinguishing between incandescent lamp lighting and human body approach. However, selecting the time is not the only means, for example, it is conceivable to select the rate of change of the sensor with time as a parameter. However, as will be discussed below, it can be seen that selecting time as a parameter has a wider application range (application) than selecting the rate of change of the sensor over time.
Here, consider the situation when the positional relationship between the infrared sensor and the incandescent lamp, especially the mutual distance changes. Of course, even if the same incandescent lamp is lit in the same way, the output level of the infrared sensor will naturally change if the distance between the infrared sensor and the incandescent lamp changes. Therefore, when the classification is performed based on the temporal change rate, the dependency on the output level, that is, the dependency on the distance change must be excluded. This means that the mutual distance needs to be constant, that is, the positional relationship between the infrared sensor and the incandescent lamp needs to be fixed. As a result, when the rate of change with time is selected as a parameter, the scope of application of the present invention is narrowed for the reasons described above.
However, it is not so difficult to eliminate the dependency due to the output level of the infrared sensor, and the temporal change rate may be normalized by the output level. That is, the temporal change rate of the sensor may be divided by the output level. The result of this division is the reciprocal of the time at which the sensor output changes. Therefore, selecting time (or its reciprocal) as a parameter has a wider range of application of the present invention than selecting a temporal change rate.
Next, the expression (3) will be described. Equation (3) indicates that both the variation in sensor output after the incandescent lamp is lit and the variation in sensor output after approaching the human body are smaller than a certain threshold value irppth3. This property is due to the fact that the sensor output level takes a substantially constant value even after the incandescent lamp is turned on or after the human body is approaching. In addition, by using this property, it is possible to more accurately perform the classification based on the change time according to the equation (2). More specifically, when sensor output variation is large, the change time is generally either not measurable or has a very long change time. On the other hand, in order to detect a short change time as described above, it is possible to measure with high accuracy by detecting a time zone in which the variation is somewhat small. In order to enable this accurate measurement, the present invention considers this property of equation (3).

  As described above, the difference between the sensor output value of the environmental change that is not to be the target of the infrared sensor measurement and the sensor output value of the target object for the infrared sensor measurement has been described. The description up to this point is based on whether the incandescent lamp is turned on (or turned off) or the human body is approaching (or separated) from the offset state (the state where the effective signal component is zero) in both cases of FIGS. I explained the case where either one happened. On the other hand, even if the target object such as the human body (hand) exists as a starting point, that is, in an effective signal detection state (non-offset state, in which the effective signal component is not zero), the target object that subsequently occurs It is the second object of the present invention to perform separation from environmental changes. For this purpose, as described in detail below, it is necessary to assume different situations and output characteristics from those described in FIGS.

[A series of situations to which the present invention is applied]: FIG. 5 is a diagram for explaining sensor output characteristics in a situation that can be dealt with by the measuring apparatus using the infrared sensor of the present invention. That is, it is a diagram showing the time change of the sensor output in a series of situations when the incandescent lamp is turned on after the human body approaches first in time series.
Also in FIG. 5, as in FIGS. 3 and 4, the horizontal axis indicates time, the vertical axis indicates the sensor output of the sensor output measuring unit 2, and the solid line in the figure indicates the actual output value of the sensor output measuring unit 2. Is shown. FIG. 5 shows a time-series change in the sensor output value when a human body (palm or the like) first approaches and then the incandescent lamp is turned on. First, it is assumed that the output value of the sensor output measuring unit 2 is adjusted to the sensor offset iof at time t0. As the adjusted iof value, as described later, the offset value corrected and updated according to the present invention may be used, or the offset value stored and held in the manufacturing process may be used. It is assumed that the human body starts approaching at time t1 (d), continues approaching until time t2 (d), and remains stationary thereafter. In this case, the output value of the sensor output measuring unit rises over a certain period of time, and thereafter takes a substantially constant value.

Subsequently, when the human body remains in a stationary state after continuing to approach, it is assumed that the incandescent lamp is turned on at time t3 (d) and is continuously turned on. In this case, the output value of the sensor output measuring unit rises within a relatively short time until time t4 (d), and thereafter takes a substantially constant value. However, as shown in FIG. 5, the sensor output when the incandescent lamp is lit at the last time t5 (d) is at a level different from the sensor output from time t2 (d) to time t3 (d). The series of situations described in FIG. 5 is further quantitatively shown using the symbols shown in FIG.
Referring to FIG. 5 again, the output value of the sensor output measuring unit 2 first starts increasing at time t1 (d) and finishes increasing at time t2 (d). Thereafter, a substantially constant output value is continuously output until time t3 (d). Irsig is defined as a representative value of the substantially constant output value. Since irsig is a representative value, it may be defined as an instantaneous value at a certain time or an average value in a certain time zone. Further, at time t3 (d), the incandescent lamp is turned on, so that the sensor output value of the sensor output measuring unit 2 starts increasing, and ends at time t4 (d). Thereafter, a substantially constant output value is continuously output until time t5 (d). Like the above irsig, irmeas is defined as a representative value of the latter almost constant output value.
The situation where the sensor output value increases from time t1 (d) to time t2 (d) in FIG. 5 is exactly the same as the situation described with reference to FIG. From time t1 (d) to time t2 (d), the time during which the output value increases is Δt (dhan), the increase in the sensor output value is Δir (dhan), and the sensor output value after the sensor output value has increased Is assumed to be irpp1 (dhan). Of course, from the above definition, Δir (dhan) = irsig−irof.
The situation in which the sensor output value increases from time t3 (d) to time t4 (d) in FIG. 5 is an increase due to incandescent lighting as described above with reference to FIG. Different as described. That is, in FIG. 3, the sensor output value before the rise is the offset level irof, whereas in FIG. 5, the sensor output value before the rise is not the offset level irof but the signal component irsig. From time t3 (d) to time t4 (d) in FIG. 5, the sensor output value rise time is Δt (dicl), the sensor output value rise is Δir (dicl), and the sensor output value rises The variation of the sensor output value is irpp1 (dicl). As will be understood from the above definition, Δir (dicl) = irmeas−irsig.
The output characteristics of the infrared sensor under the series of conditions described in FIG. 5 have the same properties as those shown in FIGS. In other words, it is known that the parameters defined as described above have properties such as the following expressions (4) and (5).
Δir (dicl)> 0, Δir (dhan)> 0 (4) Expression Δt (dicl) <Δt (dhan) (5) Also, irppth4 is a large positive threshold value (irppth4> 0). In this case, the following equation (6) holds.
irpp1 (dicl) <irppth4, irpp1 (dhan) <irppth4
(6) The expression irppth4 may be determined independently or dependent on the aforementioned irppth3.

  Regarding the output characteristics of the infrared sensor, the meanings of the expressions (4) to (6) are exactly the same as those of the expressions (1) to (3), and thus the description thereof is omitted here.

  In the series of situations described with reference to FIG. 5, first, there is an offset state as an initial state (time t0 in FIG. 5), and then an object to be measured by an infrared sensor appears, such as approaching a human body (hand). As a result, the sensor output value rises and a valid signal is detected (from t1 (d) to t2 (d) in FIG. 5). Starting from this state, the sensor output is increased due to the occurrence of environmental fluctuations that are not intended for infrared sensor measurement, such as the lighting of an incandescent lamp, afterwards (from t3 (d) to t4 (d) in FIG. 5). ).

  In the case of a series of situations as described above, the measurement apparatus and method of the present invention perform the following processing. Such processing is the most convenient and reasonable.

In other words, when the human body (hand) approaches, the human body is desired to be an object for infrared sensor measurement, so that the increase in the sensor output signal obtained by the sensor measurement is regarded as an effective signal component as it is and is increased. Just do it. On the other hand, when the incandescent lamp is lit, this incandescent lamp does not want to be the target of infrared sensor measurement, so the signal component before and after the rise of the sensor output signal is considered unchanged and the one that has changed is the offset component What is necessary is just to perform the process considered.
About the above-mentioned processing, when the series of situations shown in FIG. 5 occurs in the reverse order, that is, there is an occurrence of an environmental change that is not desired to be an infrared sensor measurement target such as incandescent lamp lighting first, It is also necessary to consider the case where the target object for the infrared sensor measurement occurs after that. Even in such a case, if processing is performed for individual situations in a series of situations that occurred in the order described in FIG. 5, without loss of generality, these cases will occur even in the reverse order. Each process can be applied as it is.

  For example, when environmental fluctuations occur first on a time series, the effective signal component remains zero and only the offset component is changed by the above-described processing, so that only the offset component is changed. Can be regarded as the offset initial value. This means returning to the offset state again after the incandescent lamp is turned on, that is, returning to the state at time t0 in FIG. 5 again. However, it should be noted that the value of iof itself generally changes depending on whether the environmental change is earlier or later. In other words, the case where the environmental change occurs first results in performing a special case process in the case where the effective signal component is zero in FIG. Therefore, the above-described processes described with reference to FIG.

  [Specific Processing Procedure of the Present Invention]: Next, the measurement of the present invention will be described with reference to the series of situations shown in FIG. A specific calculation method and determination method of processing by the apparatus will be described. In the following description, as shown in FIG. 5, the approach of the human body (hand) is located on the left side of the drawing from the lighting of the incandescent lamp. Occurrence may be simply referred to as “left side” in FIG. 5, and incandescent lighting or environmental change may be simply referred to as “right side” in FIG.

  Hereinafter, the processing procedure of the present invention will be described in detail together with each step (indicated by S) in the flowchart of FIG. The processing procedure can be broadly classified into sensor data storage processing from S601 to S606 and determination processing and sensor offset update processing from S607 to S615. Although various parameters have been defined in the description of the time series change of the sensor output in FIG. 5, in each processing procedure of the flowchart in FIG. 6, each judgment formula is presented as a plurality of “judgment conditions”. The process will be described on the assumption that the sensor output is converted into data. For example, in “first predetermined range”, “second predetermined range”, “third predetermined range”, and “fourth predetermined range”, which will be described later together with each “judgment condition”, the data to be judged corresponds to each range. It is a numerical range that defines whether or not. Therefore, it should be understood that the parameters described below and the parameters described in the description of the time series change of the sensor output in FIG. 5 do not represent the same amount but correspond to each other.

FIG. 6 is a flowchart showing a specific processing procedure executed by the measuring apparatus of the present invention in the block diagram shown in FIG. The processing procedure in FIG. 6 starts by setting the following values in advance (S601). That is, the sensor offset irof, the first threshold value irppth1, the second threshold value Δirthp (> 0, that is, a positive value), the third threshold value Δirthn (<0, that is, a negative value), the fourth value The threshold value irppth2 and the fifth threshold value Δtth are set (S601). This step (S601) corresponds to execution of initial value setting at time t0 in FIG.
These set values are the characteristics of the infrared sensor, the characteristics of the surrounding electronic devices such as operational amplifiers, the characteristics of the target object of the infrared sensor measurement (human body, etc.), and the object (environmental fluctuation) that you do not want to be the target of infrared sensor measurement. In consideration of the characteristics of the incandescent lamp, direct sunlight, etc., the application (application) of the infrared sensor measurement, the required correction accuracy, etc., it is possible to set so as to obtain an optimum correction result. For example, for iof, as described above, the offset value corrected and updated according to the present invention may be used, or the offset value stored and held in the manufacturing process may be used. In general, irppth1, Δirthp, Δirthn, irppth2, and Δtth can be fixed values determined at time t0, but can be adaptively changed based on the sensor data stored in the sensor output storage unit 4. Also good. Further, for irppth1 and irppth2, the sizes of irppth3 and irppth4 defined in the above description of [Difference in Infrared Sensor Output Characteristics] may be considered.

  When the initial value setting is completed, the processing procedure of FIG. 6 selects the data required for this processing by the sensor output selection unit 3 (S603) for the measurement value measured by the sensor output measurement unit 2 (S602). Further, the data is stored by the sensor output storage unit 4 (S604). In an actual system, since the storage area of the sensor output storage unit 4 is a finite specified value, the most unnecessary sensor data is discarded when the sensor data stored in the sensor output storage unit 4 is full ( S605-S606).

  Using a first-in first-out memory called a FIFO buffer is the simplest and practically reasonable way to select, store and discard the sensor data described above. Specifically, first, the measured values measured by the sensor output measuring unit 2 are selected and stored one after another. When a certain time elapses, the stored sensor data becomes full. At that time, the oldest sensor data is discarded. Hereinafter, a case where a FIFO buffer is used will be described as an example. Of course, the selection and storage of sensor output, the timing of discarding, and the like can be appropriately changed. Further, the sensor output handled in the following description is digital data after AD conversion, and the case where the processing after measurement is digital signal processing is described. However, the present invention is not limited to digital data. Even when the sensor output is analog data, or when the processing after measurement is analog signal processing or analog / digital mixed signal processing, the processing of the present invention is similarly performed. It can be carried out.

  As an example of the above-described data storage process, the data for the last two seconds can be stored in the sensor output storage unit 4 with the frequency of measurement of the infrared sensor being 128 Hz and the number of data in the FIFO buffer being 256. It should be noted that these settings vary only depending on the purpose and application of the measurement apparatus, the type of detection object, and the like, and are merely examples.

  Next, the processing procedure proceeds from the determination processing of S607 to S615 and the update processing of the sensor offset. First, the sensor data first variation calculation unit 5-1 calculates the variation of the sensor data stored in the sensor output storage unit 4 (S607). As explained earlier in the description of [Difference in Infrared Sensor Output Characteristics], the variations in environmental fluctuations typified by incandescent lamp lighting and the variations in objects typified by human body approach are both from a certain value. Often smaller. In order to classify the difference in the magnitude of the variation, first, the latest data is extracted from the sensor data stored in the sensor output storage unit 4. Here, it is not an essential requirement that the sensor data to be extracted is the latest data. However, in order to maximize the effects of the present invention, it is preferable to output a correction calculation result (S615), which will be described later, as soon as possible (without delay). Therefore, in general, it is preferable to extract data from the sensor output storage unit 4 so as to include the latest data.

  In this processing procedure, after extracting the sensor data, the variation of the extracted sensor data is calculated. As a preferable method of the variation calculation, the maximum value and the minimum value can be searched for the extracted sensor data, and the minimum value can be subtracted (taken out of the difference) from the maximum value. Further, the standard deviation (σ), 2σ, 3σ, or variance can be obtained for the extracted sensor data. The above-described two calculation methods are well known as indices indicating the magnitude of variation. As shown in FIG. 5, the variation obtained by any of the above-described calculation methods or other appropriate calculation methods is set to irpp1 (dhan) when the human body is approaching, and irpp1 ( dicl).

Next, in this processing procedure, the sensor data first determination unit 5-2 performs determination on irpp1 (dhan) and irpp1 (dicl) obtained by the sensor data first variation calculation unit 5-1 (S608). ). The determination is performed according to the following determination conditions. That is, it is determined to be “true” if each variation is smaller than irppth1 with respect to the first threshold value irppth1 determined in advance, and “false” if it is larger than irppth1. A range in which irpp1 (dhan) and irpp1 (dicl) are smaller than irppth1, that is, a range in which the determination result is determined to be “true” is hereinafter referred to as a “first predetermined range”. As described with reference to FIG. 5, generally, irpp1 (dhan) and irpp1 (dicl) are often smaller than a certain value. In summary, by appropriately determining the first threshold value irppth1, it is possible to make a determination based on the “first determination condition” according to the following inequality.
irpp1 (dhan) ≦ irppth1
-> The determination result of the sensor data first determination unit 5-2 is true irpp1 (dicl) ≦ irppth1
-> The determination result of the sensor data first determination unit 5-2 is true. If the above inequality is not satisfied, for example, in the region where the sensor output data is changing in FIG. It is clear that when the variation is calculated by the first variation calculating unit, the variation becomes a large value. In such a case, the inequality of the “first determination condition” is not satisfied. When the determination result of the sensor data first determination unit 5-2 is “false”, the sensor offset correction is not executed, and the control flow of this processing procedure returns to S602 of FIG.
On the other hand, when the sensor output corresponds to the area indicated by irpp1 (dhan) and irpp1 (dicl) in FIG. 5, the determination result of the sensor data first determination unit 5-2 is determined to be “true”, and this processing is performed. The procedure proceeds to the next sensor data second determination unit 5-3 (S609). In this case, first, the sensor data first variation calculation unit 5-1 calculates the representative value of the sensor data extracted from the sensor output storage unit 4. As this representative value, the average value of a plurality of sensor data extracted from the sensor output storage unit 4 is generally used, but the median (median), maximum value, minimum value, maximum value and minimum value, Or an instantaneous value at a certain time such as the latest sensor data may be used. When the determination result of the sensor data first determination unit 5-2 is determined to be “true”, since the variation value of the sensor data originally extracted from the sensor output storage unit 4 is small, various representative values are set. You can choose. The representative values are irsig (in the case of the left side in FIG. 5) and irmeas (in the case of the right side in FIG. 5).
Subsequently, the sensor data second determination unit 5-3 first sets one of the following conditions as the “second determination condition”.
Sensor data stored in sensor output storage section> irthp (7-1) formula Sensor data stored in sensor output storage section <irthn (8-1) formula Here, irthp and irthn are shown in FIG. Each symbol is defined by the following equations.
Irthp = irsig + Δirthp: When the left side of FIG. 5 (9-1) Equation irthn = irsig + Δirthn: When the left side of FIG. 5 (9-2) Equation irthp = irmeas + Δirthsp: When right side of FIG. 5 (9-3) 5 Right side (9-4) Furthermore, when it corresponds to the left side of FIG. 5, (7-1) type | formula uses (9-1) type | formula, (8-1) type | formula (9) -2), each can be transformed into the following equation.
Sensor data stored in the sensor output storage unit—irsig> Δirthp (7-2) Equation Sensor data stored in the sensor output storage unit—irsig <Δirthn (8-2) equation The case corresponding to the right side of FIG. Irsig in equations (7-2) and (8-2) may be replaced with irsig.

Here, the result of subtracting the representative value irsig from the sensor data stored in the sensor output storage unit 4 is greater than a predetermined positive threshold value Δirthp or stored in the sensor output storage unit 4 A range in which any one of the results of subtracting the representative value irsig from the sensor data is smaller than a predetermined negative threshold value Δirthn is referred to as a “second predetermined range”. In FIG. 5, this “second predetermined range” is shown by hatching on the right side of FIG. 5, that is, as a range for condition determination corresponding to the lighting of an incandescent lamp or the occurrence of environmental fluctuation. Conditional expressions corresponding to this range are the above expressions (9-3) and (9-4). Although not shown in FIG. 5, the “second predetermined range” on the left side of FIG. 5, that is, corresponding to the approach of the human body (hand) or the generation of the object of sensor measurement is (9-1) and (9 -2). Or it is given by the equations (7-2) and (8-2).
In the above description of [difference in infrared sensor output characteristics], only the case where the formula (9-4) or the formula (9-2) is applied has been described. That is, Equations (9-4) and (9-2) are inequalities applied when the incandescent lamp is turned on from the extinguished state or when the human body approaches. Conversely, the equations (9-3) and (9-1) are inequalities applied when the incandescent lamp is turned off from the lighting state or when the human body is moving away. In the embodiment of the present invention, any one of these inequalities or a combination of both is applied as the determination condition.
In the processing in the measuring apparatus 100 of the present invention, there are a plurality of sensor data stored in the sensor output storage unit 4, and among these plural numbers, (9-3) and (9-4) (or ( If there is at least one sensor data that satisfies the inequalities of the formulas (9-1) and (9-2)), the determination result by the sensor data second determination unit 5-3 is determined to be “true” ( S609). It should be noted that, in the determination by the sensor data second determination unit 5-3, it is not the determination condition of the present invention that all of the plurality of sensor data satisfy the above condition.

Therefore, conversely, the condition that the determination result of the sensor data second determination unit 5-3 is “false” is when all of the plurality of sensor data do not satisfy the inequality of the “second determination condition”. A typical example in which it is determined as “false” is a case where there is an object or environmental variation, but the sensor output due to the presence of the target or environmental variation remains unchanged for some time. As described above, when the determination result of the sensor data second determination unit 5-3 is “false”, the correction of the sensor offset is not executed, and the control flow of this processing procedure returns to S602.
On the other hand, a typical example in which the determination result of the sensor data second determination unit 5-3 is determined to be “true” is as follows. For example, this is due to an increase in sensor output (due to incandescent lamp lighting) from time t3 (d) to time t4 (d) on the right side of FIG. 5, that is, the situation shown in FIG. Further, although not illustrated in the description of the determination condition in the sensor data second determination unit 5-3, the sensor output increase due to the approach of the human body from time t1 (d) to t2 (d) on the left side of FIG. Can be determined. That is, in the case of irpp1 (dhan) and irpp1 (dicl) shown in FIG. 5, the determination result of the sensor data second determination unit 5-3 is determined to be “true”, and this processing procedure is performed with the next sensor data. The process proceeds to the second variation calculation unit 5-4.
The sensor data second variation calculation unit 5-4 calculates the variation of the sensor data stored in the sensor output storage unit 4 (S610). This variation calculation is similar to the purpose of the sensor data first variation calculation unit 5-1, and the variations in environmental fluctuations typified by incandescent lamp lighting and the variations in objects typified by human body approach are both from a certain value. Since it often becomes smaller, it is executed to distinguish the difference between the two. First, some of the data satisfying the inequality of equation (7-1) or (8-1) is extracted from the plurality of sensor data stored in the sensor output storage unit 4.

As described above, the sensor data extracted in the sensor data first variation calculation unit 5-1 is sensor data including the latest data. On the other hand, any number of sensor data extracted by the sensor data second variation calculation unit 5-4 may be extracted as long as the data satisfies the inequality of equation (7-1) or (8-1). However, do not extract data that does not satisfy these inequalities. The reason is that if these inequality equations are extracted from data that does not satisfy these inequalities, the subsequent calculation of the change time becomes impossible or unstable. Further, for the same reason as the calculation of the change time described above, among data satisfying the inequality of the equation (7-1) or the equation (8-1), a predetermined number of data is obtained from data at a time as close as possible to the current time. It is preferable to extract data.
After extracting appropriate sensor data, the variation of the extracted sensor data is calculated. As a calculation method, the maximum value and the minimum value can be searched for the extracted sensor data, and the minimum value can be subtracted from the maximum value (difference is taken). Further, the standard deviation (σ), 2σ, 3σ, or variance can be obtained for the extracted sensor data. The above-described two calculation methods are well known as indices indicating the magnitude of variation. The variation obtained by any one of these calculation methods or another appropriate calculation method is irpp2 (dhan) as shown in FIG. 5 when the human body is approaching, and irpp2 (dicl) when the incandescent lamp is lit. To do.
Next, in this processing procedure, the sensor data third determination unit 5-5 performs determination on irpp2 (dhan) and irpp2 (dicl) obtained by the sensor data second variation calculation unit 5-4 ( S611). The determination is performed according to the following determination conditions. That is, it is determined to be “true” if each variation is smaller than irppth2 with respect to the fourth threshold value irppth2 determined in advance by default, and “false” if it is larger than irppth2. A range in which irpp2 (dhan) and irpp2 (dicl) are smaller than irppth2, that is, a range in which the above determination result is determined to be “true” is hereinafter referred to as a “third predetermined range”. As described with reference to FIG. 5, generally, irpp2 (dhan) and irpp2 (dicl) are often smaller than a certain value. Accordingly, by appropriately determining the fourth threshold value irppth2, it is possible to make a determination based on the “third determination condition” of the following inequality.
irpp2 (dhan) ≦ irppth2
-> The determination result of the sensor data third determination unit 5-5 is true irpp2 (dicl) ≦ irppth2
-> The determination result of the sensor data third determination unit 5-5 is true.

On the other hand, when the inequality of the above “third determination condition” is not satisfied, for example, in the state where the sensor data is changed due to the lighting of the incandescent lamp in FIG. If the variation is calculated at −4, it is clear that the variation takes a large value, and the inequality of the “third determination condition” is not satisfied. In such a case, only the data determined as “true” by the sensor data second determination unit 5-3 is used, and the data in the vicinity of irpp2 (dicl) (indicated by ☆ in FIG. 5) is extracted and determined. , The above inequality is established. More specifically, in the case of the “third determination condition” determination, it is reasonable and practical to perform the following processing.
As a first example of the determination of the “third determination condition”, the inequality of the “third determination condition” is first selected from the data determined as “true” by the sensor data second determination unit 5-3 (S609). Data different from the data used when it is determined that is not established is extracted. Thereafter, a variation calculation similar to that performed by the sensor data second variation calculation unit 5-4 is performed again (S610), and whether irpp2 (dhan) and irpp2 (dicl) are larger or smaller than irppth2 based on the variation calculation result. judge. That is, it is determined again whether or not the “third determination condition” inequality is satisfied. Here, if the inequality of the “third determination condition” is not satisfied, the process of the first example described above is further repeated a predetermined number of times or as much as possible. If the inequality of “third determination condition” is not satisfied even if the determination is repeatedly performed, the determination result of the sensor data third determination unit 5-5 is determined to be “false”. This iterative process is a so-called “polling process” and is a process indicated by a dotted line from the sensor data third determination unit 5-5 to the sensor data second variation calculation unit in FIG.
The second example of the determination of “third determination condition” is an example showing a more specific processing method of the first example, and is as follows. As described in the first example, first, among the data determined to be “true” by the sensor data second determination unit 5-3, data is determined from data at a time (most recent) as close as possible to the current time. Extract number data. The same calculation as that of the sensor data second variation calculation unit 5-4 is performed on the data. Thereafter, based on the calculation result, it is determined whether irpp2 (dhan) and irpp2 (dicl) are larger or smaller than irppth2, that is, whether the inequality of the “third determination condition” is satisfied.

Here, if the above inequality is not satisfied, one of the latest data is excluded from the previously extracted data, and one of the latest data is added to the data that has not been previously extracted, and the object of the new calculation Data. The same calculation as the sensor data second variation calculation unit 5-4 is performed again on the new calculation target data. In the subsequent determination, as in the first example, the result of the sensor data third determination unit 5-5 is determined to be “true” when the inequality “third determination condition” is satisfied. If the inequality of the “third determination condition” is not satisfied even after the predetermined number of repetitions, the result of the sensor data third determination unit 5-5 is determined to be “false”.
The third example of the determination of the “third determination condition” is that sensor data of any combination is acquired from the sensor data second determination unit 5-3, and the same calculation as the sensor data second variation calculation unit 5-4 is performed. Execute for all combinations of. The minimum value or the minimum value of the calculation result can be changed to the calculation result obtained by the sensor data second variation calculation unit. Thereafter, in the sensor data third determination means 5-5, based on the above-described calculation result, irpp2 (dhan) and irpp2 (dicl) are compared with irppth2 based on the calculation result. It is also possible to determine “false”.

  When the determination result of the sensor data third determination unit 5-5 determined as described above is “false”, the sensor offset correction is not performed, and the control flow of this processing procedure returns to S602. On the other hand, in the case of irpp2 (dhan) and irpp2 (dicl) in FIG. 5, the determination result of the sensor data third determination unit 5-5 is determined as “true”, and this processing procedure is the next sensor data change time calculation. The process proceeds to unit 5-6.

It should be noted that the reference point for the measurement of the change time described below is clarified by repeating the determination process until the determination of “true” is obtained by the third determination condition described above.
The sensor data change time calculation unit 5-6 measures the change time of the sensor data stored in the sensor output storage unit 4 (S612). The change time is generally the most distant time of data that takes a second level of another constant value different from the first level from the most recent time of data that takes a certain level of the first level. Is defined as Hereinafter, based on the definition of the change time, details of the change time calculation method will be described.
The change time in the present invention generally corresponds to a rise time or fall time in an electric / electronic circuit. For example, recall the rise time of a pulse in a logic circuit. The most common and exact definition of the rise time is the time from 10% of the amplitude (difference between high level and low level) to the time of 90% of the waveform transitioning from the low level to the high level. It is. For the fall time, the low level and the high level, and 10% and 90% may be replaced in the definition of the rise time.
In the present invention, since the means for performing the measurement is a general sensor including an infrared sensor, a concept such as low level and high level in the above-described logic circuit, or 10% amplitude and 90% amplitude is directly applied. I can't. However, as a concept applicable to both the electrical and electronic circuit and the output of the infrared sensor, the change time can be calculated by defining as follows.

  Concept corresponding to low level or amplitude of 10%: The sensor data is within the “third predetermined range”. That is, it exists within the range of the predetermined threshold value Δirppth2.

Concept corresponding to the high level or the amplitude of 90%: The sensor data exists in the “first predetermined range”. That is, it exists within the range of the predetermined threshold value Δirppth1.
The concept of the above-described low level and high level (amplitudes of 10% and 90%) may not necessarily match the “large” and “small” relationships of actual sensor data output. For example, as shown in FIG. 5, when the sensor output changes, when the human body (hand) approaches, or when an incandescent lamp is lit, generally, the sensor data output “large” and “small” “The relationship between the high level and the low level is the same. That is, “large” of the sensor data output corresponds to the high level, and “small” of the sensor data output corresponds to the low level. On the other hand, this relationship may be reversed. For example, when the human body (hand) is separated or the incandescent lamp is turned off.
Based on the concept and definition of the rise time or fall time described above, the change time in the present invention is determined from the time when the sensor data stored in the sensor output storage unit 4 falls within the “third predetermined range”. , “Time until the time within the first predetermined range”. In a more strict definition, the “first predetermined range” from the closest (most recent) time from the current time in which the sensor data stored in the sensor output storage unit 4 is within the “third predetermined range”. What is necessary is just to define as "the time to the oldest (farthest) time" in. When the change time calculated based on the latter definition corresponds to the approach of the human body (hand) on the left side of FIG. 5 or the generation of the object of sensor measurement, Δt (dhan), the incandescent lamp on the right side of FIG. Is represented as Δt (dicl) when it corresponds to lighting or environmental fluctuation.
In this processing procedure, Δt (dhan) and Δt (dicl) obtained by the sensor data change time calculation unit 5-6 by the above-described calculation method are determined by the next sensor data fourth determination unit 5-7. Execute (S613). The determination conditions are as follows. That is, it is determined as “true” if Δt (dhan) and Δt (dicl) are smaller than Δtth, and “false” if larger than Δtth, with respect to the fifth threshold value Δtth set in the initial setting in advance. . Here, a range in which the values Δt (dhan) and Δt (dicl) obtained by the sensor data change time calculator 5-6 are smaller than Δtth, that is, a range in which the above determination result is determined to be “true”. Is hereinafter referred to as “fourth predetermined range”.

As described with reference to FIG. 5, Δt (icdl) is generally smaller than Δt (hand). Therefore, by determining Δtth appropriately, determination based on the following “fourth determination condition” becomes possible.
Δt (dhan) ≧ Δtth
The determination result of the sensor data fourth determination unit 5-7 is false (left side in FIG. 5)
Δt (dicl) <Δtth
The determination result of the sensor data fourth determination unit 5-7 is true (right side in FIG. 5).
When the determination result of the sensor data fourth determination unit 5-7 is “false” as shown on the left side of FIG. 5, the sensor offset correction is not executed, and the control flow of this processing procedure returns to S602 of FIG. On the other hand, in the case of the right side of FIG. 5, the determination result of the sensor data fourth determination unit is determined to be “true”. In this case, the processing procedure proceeds to the processing of the next sensor offset estimation unit 5-8.

  As is apparent from the description of S608 to S613 in the above processing procedure, the sensor offset estimation unit 5-8 performs the processes of the sensor data first determination unit 5-2 and the sensor data second determination unit. 5-3, only when all the determination results of the sensor data third determination unit 5-5 and the sensor data fourth determination unit 5-7 are “true”.

In this processing procedure, the sensor offset estimation unit 5-8 first calculates an estimated value of the sensor offset (S614). Hereinafter, if the offset estimated value is irofnew, irofnew can be calculated by the following equation by calculating irsig and irmeas shown in FIG.
irofnew = irmeas− (irsig−irof) (10) At this time, irsig is infrared sensor data at a time within a range of “second predetermined range” or “third predetermined range”. That is, since it is the infrared sensor data value (or effective signal component value) at the past time, the value may be stored and stored, or based on the sensor data stored in the sensor output storage unit 4. You may calculate.
Further, irmeas may use the current sensor output data at time t5 (d) as it is, or extract any sensor output from time t4 (d) to time t5 (d) in order to improve accuracy. The average value may be calculated. Alternatively, an average value of a predetermined number of sensor outputs immediately before the current time including the time t5 (d) may be calculated and calculated. Furthermore, when calculating the average value, a weighted average value or the like can be calculated and used instead of a simple average.

In this processing procedure, the sensor offset update unit 5-9 updates the offset estimated value calculated by the above calculation as a new sensor offset value of the present system including the infrared sensor 1 (S615). That is, the sensor offset value after the time t5 (d) is updated to iofnew instead of the predetermined iofof.
The description so far is a specific example of the case where the sensor output changes as shown in FIG. 5, that is, the case where the sensor output increases due to the approach of the human body (hand) and the case where the sensor output increases due to the lighting of the incandescent lamp. As shown. It is apparent that the present invention is not limited to the case where the sensor output increases as described above, but can be similarly applied to the case where the sensor output decreases. Based on the magnitude or smallness of the sensor output, it is only necessary to reverse the magnitude relationship and sign in the above description as appropriate.

  Finally, by using the offset correction result according to the present invention, it is possible to easily set the threshold value in the presence / absence detection of the binarized object. That is, since the offset of the infrared sensor is automatically corrected, the threshold value may be set according to the offset correction value. As a specific example, even if the offset becomes very large due to the lighting of the incandescent lamp and increases, for example, by 1000, the threshold value only needs to be increased by 1000 accordingly.

  Therefore, even in the case of detecting the presence / absence of a binarized object, a system design including setting of a threshold value can be performed more easily.

  INDUSTRIAL APPLICABILITY The present invention can be used for a measuring device that uses an infrared sensor that detects the presence / absence, position, and movement of an object. Furthermore, it can also be used for mobile phones and electronic games.

DESCRIPTION OF SYMBOLS 1 Infrared sensor part 2 Sensor output measurement part 3 Sensor output selection part 4 Sensor output storage part 5 Sensor offset correction | amendment part 5-1 Sensor data 1st dispersion | variation calculation part 5-2 Sensor data 1st determination part 5-3 Sensor data 2nd Determination unit 5-4 Sensor data second variation calculation unit 5-5 Sensor data third determination unit 5-6 Sensor data change time calculation unit 5-7 Sensor data fourth determination unit 5-8 Sensor offset estimation unit 5-9 Sensor Offset update unit 100 Measuring device

Claims (42)

An infrared sensor;
Measuring means for measuring the output value of the infrared sensor;
Selecting means for selecting a plurality of infrared sensor data from the infrared sensor output values measured by the measuring means;
Storage means for storing infrared sensor data selected by the selection means;
Correction means for correcting the offset of the infrared sensor based on the infrared sensor data stored by the storage means;
With
The correction means is
First variation calculating means for calculating variations of the infrared sensor data based on the infrared sensor data stored by the storage means;
First determination means for determining whether or not the variation of the infrared sensor data calculated by the first variation calculation means is within a first predetermined range;
Second determination means for determining whether at least one of the infrared sensor data stored by the storage means is within a second predetermined range;
Second variation calculation means for calculating variations of the infrared sensor data based on the infrared sensor data stored by the storage means;
Third determination means for determining whether or not the variation of the infrared sensor data calculated by the second variation calculation means is within a third predetermined range;
Based on the infrared sensor data stored by the storage means, change time calculation means for calculating the change time of the infrared sensor data;
Fourth determination means for determining whether or not the change time of the infrared sensor data calculated by the change time calculation means is within a fourth predetermined range;
Estimating means for estimating an offset of the infrared sensor when all the determination results of the first determining means, the second determining means, the third determining means, and the fourth determining means are determined to be true;
And an updating unit that updates an offset of the infrared sensor based on a result of the estimating unit. A measuring apparatus using an infrared sensor. The selection means includes
2. The measuring apparatus using an infrared sensor according to claim 1, wherein the measuring apparatus is a means for selecting a plurality of infrared sensor data within a predetermined time nearest to the output value of the infrared sensor measured by the measuring means. The first variation calculating means includes:
2. The measuring device using an infrared sensor according to claim 1, wherein the measuring device is a means for calculating a difference between a maximum value of infrared sensor data stored by the storage means and a minimum value of the data. The first variation calculating means includes:
2. The measuring device using an infrared sensor according to claim 1, wherein the measuring device is a means for calculating a standard deviation or variance of infrared sensor data stored by the storage means. The first variation calculating means includes:
The latest data selection means for selecting a plurality of infrared sensor data including recent infrared sensor data from the infrared sensor data stored by the storage means,
5. The measuring apparatus using an infrared sensor according to claim 1, wherein variation of infrared sensor data selected by the latest data selection unit is calculated. The first determination means includes
The measuring apparatus using an infrared sensor according to claim 1, wherein the measuring device is a unit that determines to be true when the calculation result obtained by the first variation calculating unit is equal to or less than a predetermined threshold value. The second determination means includes
Representative value calculating means for further calculating a representative value of the infrared sensor data calculated in the first variation calculating means;
Representative value difference calculating means for calculating a difference from the representative value calculated by the representative value calculating means from the infrared sensor data stored by the storing means;
Including
The second determination means includes
It is determined to be true when at least one of the calculation results obtained by the representative value difference calculation means is greater than or equal to a predetermined threshold value or less than or equal to a predetermined threshold value. A measuring apparatus using the infrared sensor according to claim 1. The representative value calculating means includes:
The measuring device using an infrared sensor according to claim 7, wherein the measurement is performed as an average value of infrared sensor data calculated by the first variation calculating means. The second variation calculating means includes:
2. The measuring device using an infrared sensor according to claim 1, wherein the measuring device is a means for calculating a difference between the maximum value of the infrared sensor data stored by the storage means and the minimum value of the same data. The second variation calculating means includes:
2. The measuring device using an infrared sensor according to claim 1, wherein the measuring device is a means for calculating a standard deviation or variance of infrared sensor data stored by the storage means. The second variation calculating means includes:
Including post-determination data selection means for selecting a plurality of infrared sensor data including infrared sensor data for which the determination result of the second determination means is determined to be true from the infrared sensor data stored by the storage means;
The measuring device using an infrared sensor according to claim 1, wherein variation of infrared sensor data selected by the post-judgment data selection unit is calculated. The third determination means includes
2. The measuring apparatus using an infrared sensor according to claim 1, wherein the measuring device is a means for determining true when the calculation result obtained by the second variation calculating means is equal to or less than a predetermined threshold value. The third determination means includes
Calculating means for calculating the second variation calculating means a predetermined number of times,
The third determination means includes
13. The measuring apparatus according to claim 1, wherein the measuring device is a means for determining false when all of the calculation results calculated by the second variation calculating means a predetermined number of times are not less than a predetermined threshold value. . The change time calculating means includes
The infrared sensor data is calculated as a time from a time when the infrared sensor data is within the third predetermined range to a time when the infrared sensor data is within the first predetermined range. A measuring device using the infrared sensor according to claim 1. The change time calculating means includes
The infrared sensor data is calculated as the time from the most recent time when the infrared sensor data is within the third predetermined range to the farthest time when the infrared sensor data is within the first predetermined range. A measuring device using the infrared sensor according to claim 1. The fourth determination means includes
2. The infrared sensor according to claim 1, wherein the change time calculated by the change time calculation means is a means for determining true when the change time is equal to or less than a predetermined threshold value. Measuring device. The estimation means includes
A signal difference calculation means for calculating a difference between the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the second predetermined range;
Signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means,
The estimation means includes
From the infrared sensor data at the determination time when all the determination results of the first determination means, the second determination means, the third determination means, and the fourth determination means are determined to be true, the signal difference calculation result storage means It is an estimation means that uses the difference from the stored signal difference calculation result as an offset estimated value,
The measuring device using an infrared sensor according to claim 1, wherein the updating unit is an updating unit that updates an offset value to the offset estimation value. The estimation means includes
A signal difference calculating means for calculating a difference from the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the third predetermined range;
Signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means,
The estimation means includes
From the infrared sensor data at the determination time when all the determination results of the first determination means, the second determination means, the third determination means, and the fourth determination means are determined to be true, the signal difference calculation result storage means It is an estimation means that uses the difference from the stored signal difference calculation result as an offset estimated value,
The measuring device using an infrared sensor according to claim 1, wherein the updating unit is an updating unit that updates an offset value to the offset estimation value. The estimation means includes
A signal difference calculation means for calculating a difference between the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the second predetermined range;
Signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means,
The estimation means includes
Calculation is performed based on a predetermined number of infrared sensor data after a determination time at which all the determination results of the first determination unit, the second determination unit, the third determination unit, and the fourth determination unit are determined to be true. From the calculation result is an estimation means that uses a difference between the signal difference calculation result stored by the signal difference calculation result storage means and an offset estimated value;
The measuring device using an infrared sensor according to claim 1, wherein the updating unit is an updating unit that updates an offset value to the offset estimation value. The estimation means includes
A signal difference calculating means for calculating a difference from the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the third predetermined range;
Signal difference calculation result storage means for storing a signal difference calculation result obtained by the signal difference calculation means,
The estimation means includes
Calculation is performed based on a predetermined number of infrared sensor data after a determination time at which all the determination results of the first determination unit, the second determination unit, the third determination unit, and the fourth determination unit are determined to be true. From the calculation result is an estimation means that uses a difference between the signal difference calculation result stored by the signal difference calculation result storage means and an offset estimated value;
The measuring device using an infrared sensor according to claim 1, wherein the updating unit is an updating unit that updates an offset value to the offset estimation value. Threshold setting means for presetting a predetermined threshold;
Comparison means for comparing the threshold value set by the threshold value setting means with the current infrared sensor measurement value;
The measurement apparatus using an infrared sensor according to claim 1, further comprising: an infrared sensor detection determination unit that determines whether or not the infrared sensor is detected based on a result of the comparison unit. A measurement step for measuring the output value of the infrared sensor;
A selection step of selecting a plurality of infrared sensor data from the infrared sensor output values measured by the measurement step;
A storage step of storing the infrared sensor data selected by the selection step;
A correction step of correcting the offset of the infrared sensor based on the infrared sensor data stored in the storage step;
The correction step includes
A first variation calculating step for calculating variations in the infrared sensor data based on the infrared sensor data stored in the storing step;
A first determination step of determining whether or not the variation of the infrared sensor data calculated in the first variation calculation step is within a first predetermined range;
A second determination step of determining whether at least one of the infrared sensor data stored in the storing step is within a second predetermined range;
A second variation calculating step for calculating variations in the infrared sensor data based on the infrared sensor data stored in the storing step;
A third determination step of determining whether or not the variation of the infrared sensor data calculated in the second variation calculation step is within a third predetermined range;
Based on the infrared sensor data stored in the storing step, a change time calculating step for calculating a change time of the infrared sensor data;
A fourth determination step of determining whether or not the change time of the infrared sensor data calculated by the change time calculation step is within a fourth predetermined range;
An estimation step for estimating an offset of the infrared sensor when all the determination results of the first determination step, the second determination step, the third determination step, and the fourth determination step are determined to be true;
An update step of updating an offset of the infrared sensor based on a result of the estimation step. A calibration method for a measuring apparatus using an infrared sensor, comprising: The selection step includes
23. The method according to claim 22, wherein a plurality of infrared sensor data are selected within a predetermined time nearest to an infrared sensor output value measured by the measuring step. The first variation calculating step includes:
The method according to claim 22, wherein the calculation is performed as a difference between the maximum value of the infrared sensor data stored by the storing step and the minimum value of the data. The first variation calculating step includes:
The method according to claim 22, wherein the calculation is performed as a standard deviation or variance of the infrared sensor data stored by the storing step. The first variation calculating step includes:
A latest data selection step of selecting a plurality of infrared sensor data including recent infrared sensor data from the infrared sensor data stored by the storing step;
26. The method according to claim 22, 24 or 25, wherein the variation of the infrared sensor data selected by the most recent data selection step is calculated. The first determination step includes
23. The method according to claim 22, wherein the determination is true when the calculation result obtained by the first variation calculation step is equal to or less than a predetermined threshold value. The second determination step includes
A representative value calculating step of further calculating a representative value of the infrared sensor data calculated in the first variation calculating step;
A representative value difference calculating step of calculating a difference from the representative value calculated by the representative value calculating step from the infrared sensor data stored by the storing step;
Including
The second determination step includes
It is determined to be true when at least one of the calculation results obtained by the representative value difference calculation step is equal to or greater than a predetermined threshold value or less than or equal to a predetermined threshold value. 23. A method according to claim 22, characterized in that The representative value calculating step includes:
The method according to claim 28, wherein the calculation is performed as an average value of the infrared sensor data calculated in the first variation calculating step. The second variation calculating step includes:
The method according to claim 22, wherein the calculation is performed as a difference between the maximum value of the infrared sensor data stored in the storing step and the minimum value of the data. The second variation calculating step includes:
The method according to claim 22, wherein the calculation is performed as a standard deviation or variance of the infrared sensor data stored by the storing step. The second variation calculating step includes:
A post-determination data selection step of selecting a plurality of infrared sensor data including the infrared sensor data in which the determination result of the second determination step is determined to be true from the infrared sensor data stored in the storing step;
32. The method according to claim 22, 28, 30 or 31, wherein the variation of the infrared sensor data selected in the post-determination data selection step is calculated. The third determination step includes
23. The method according to claim 22, wherein the determination is true when the calculation result obtained by the second variation calculation step is equal to or less than a predetermined threshold value. The third determination step includes
Calculating the second variation calculating step a predetermined number of times, and
The third determination step includes
34. The measuring apparatus according to claim 22 or 33, wherein it is determined to be false when all the calculation results calculated a predetermined number of times in the second variation calculation step are equal to or greater than a predetermined threshold value. The change time calculating step includes:
The infrared sensor data is calculated as a time from a time when the infrared sensor data is within the third predetermined range to a time when the infrared sensor data is within the first predetermined range. The method of claim 22. The change time calculating step includes:
The infrared sensor data is calculated as the time from the most recent time when the infrared sensor data is within the third predetermined range to the farthest time when the infrared sensor data is within the first predetermined range. 23. The method of claim 22, wherein: The fourth determination step includes
23. The method according to claim 22, wherein the determination is true when the change time calculated by the change time calculation step is equal to or less than a predetermined threshold value. The estimation step includes
A signal difference calculation step of calculating a difference between the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the second predetermined range;
A signal difference calculation result storage step for storing a signal difference calculation result obtained by the signal difference calculation step,
The estimation step includes
From the infrared sensor data at the determination time when all the determination results of the first determination step, the second determination step, the third determination step, and the fourth determination step are determined to be true, the signal difference calculation result storage step It is an estimation step in which the difference from the stored signal difference calculation result is an offset estimation value,
The method according to claim 22, wherein the updating step is an updating step of updating an offset value to the offset estimation value. The estimation step includes
A signal difference calculation step of calculating a difference between the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the third predetermined range;
A signal difference calculation result storage step for storing a signal difference calculation result obtained by the signal difference calculation step,
The estimation step includes
From the infrared sensor data at the determination time when all the determination results of the first determination step, the second determination step, the third determination step, and the fourth determination step are determined to be true, the signal difference calculation result storage step It is an estimation step in which the difference from the stored signal difference calculation result is an offset estimation value,
The method according to claim 22, wherein the updating step is an updating step of updating an offset value to the offset estimation value. The estimation step includes
A signal difference calculation step of calculating a difference between the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the second predetermined range;
A signal difference calculation result storage step for storing a signal difference calculation result obtained by the signal difference calculation step,
The estimation step includes
Calculation is performed based on a predetermined number of infrared sensor data after the determination time when all the determination results of the first determination step, the second determination step, the third determination step, and the fourth determination step are determined to be true. From the calculation result, an estimation step in which a difference from the signal difference calculation result stored in the signal difference calculation result storage step is an offset estimated value,
The method according to claim 22, wherein the updating step is an updating step of updating an offset value to the offset estimation value. The estimation step includes
A signal difference calculation step of calculating a difference between the infrared sensor offset of a predetermined infrared sensor from infrared sensor data at a time falling within the third predetermined range;
A signal difference calculation result storage step for storing a signal difference calculation result obtained by the signal difference calculation step,
The estimation step includes
Calculation is performed based on a predetermined number of infrared sensor data after the determination time when all the determination results of the first determination step, the second determination step, the third determination step, and the fourth determination step are determined to be true. From the calculation result, an estimation step in which a difference from the signal difference calculation result stored in the signal difference calculation result storage step is an offset estimated value,
The method according to claim 22, wherein the updating step is an updating step of updating an offset value to the offset estimation value. A threshold setting step for presetting a predetermined threshold;
A comparison step of comparing the threshold set by the threshold setting step with the current infrared sensor measurement value;
An infrared sensor detection determination step for determining whether the infrared sensor is detected based on the result of the comparison step;
The method of claim 22, further comprising:

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