JP2021081192A - Linearity correction method of optical measuring device, optical measuring method and optical measuring device - Google Patents

Abstract

To perform linearity correction with high accuracy for an optical measuring device using a CMOS linear image sensor.SOLUTION: Provided is a linearity correction method for an optical measuring device comprising a CMOS linear image sensor and including: an exposure step of sequentially making a reference light of constant intensity incident on a light receiving element of interest of the CMOS linear image sensor by changing exposure time; a measured value acquisition step of sequentially acquiring a measured value of the light receiving element of interest; an actual linearity error calculation step of sequentially calculating an actual linearity error indicating the difference between the measured value and a linear value obtained based on the exposure time corresponding to the measured value; and a fitting step of executing fitting of a first function indicating a first linearity error for each of the actual linearity errors.SELECTED DRAWING: Figure 9

Description

The present invention relates to a linearity correction method for an optical measuring device, an optical measuring method, and an optical measuring device.

CCD (Charged-coupled devices) linear image sensors may be used in optical measuring devices such as multi-channel spectroscopes. A specific wavelength portion of the measurement light dispersed by the diffraction grating is incident on each light receiving element arranged in the CCD linear image sensor, and an electric signal corresponding to the light intensity is output from the light receiving element. However, although the CCD linear image sensor generally has an advantage of high sensitivity, the structure tends to be complicated and expensive.

Japanese Unexamined Patent Publication No. 5-15628

A CMOS (Complementary Metal Oxide Semiconductor) linear image sensor is also known as an electronic component having the same function as a CCD linear image sensor. The CMOS linear image sensor has advantages that the structure is relatively simple, the cost is low, the power consumption is low, and the speed is easy to increase.

However, the CMOS linear image sensor has a drawback that the linearity is inferior to that of the CCD linear image sensor. That is, there is a drawback that even if light having an intensity of α times is incident on each light receiving element arranged in the CMOS linear image sensor, a measured value of α times cannot always be obtained. Therefore, there is a problem that the intensity of the measured light cannot be immediately determined from the raw output value of the CMOS linear image sensor. Therefore, when a CMOS linear image sensor is used in the optical measuring device, high-precision linearity correction is required.

The present invention has been made in view of the above problems, and an object of the present invention is a linearity correction method capable of performing linearity correction of an optical measuring device using a CMOS linear image sensor with high accuracy, and optics using the method. It is an object of the present invention to provide a measuring method and an optical measuring device.

In order to solve the above problems, the linearity correction method according to the present invention is the linearity correction method of an optical measuring device including a CMOS linear image sensor, in which a reference light having a constant intensity is used and the exposure time is changed to change the exposure time of the CMOS linear image sensor. An exposure step in which the light receiving element is sequentially incident on the light receiving element, a measurement value acquisition step in which the measured values of the light receiving element of interest are sequentially acquired, a linear value obtained based on the exposure time corresponding to the measured value, and the measured value. A real linearity error calculation step for sequentially calculating a real linearity error indicating a difference between the two and a fitting step for executing a fitting of a first function indicating a first linearity error for each actual linearity error is included. It is a feature.

Here, the first function may be a quadratic function.

Further, in the fitting step, the variable parameter of the first function may be determined by the least squares method using an objective function indicating the total amount of the difference between each actual linearity error and the first linearity error. The objective function may include a term indicating the difference between the first linearity error and the actual linearity error corresponding to each measured value. These terms may be weighted by the amount of variation indicating the variation of each of the measured values.

In addition, an exposure time correction step of performing exposure time correction on the measured value corrected by the first function may be further included.

Further, in the exposure time correction step, the exposure time correction may be performed by applying a second function that approaches a predetermined value as the exposure time becomes longer to the measured value corrected by the first function.

Here, the second function may be a fractional function.

Further, the measured value is the difference between the first output value of the attention receiving element when the reference light is incident and the second output value of the attention receiving element when the reference light is not incident. May be obtained based on.

Further, in the fitting step, the fitting may be executed by using the measured value acquired based on the first output value equal to or higher than a predetermined threshold value.

Further, the CMOS linear image sensor may include a non-attention light receiving element in which no light is incident during the time when the reference light is incident on the attention light receiving element. At this time, the linearity correction method may further include a base correction value calculation step of calculating a base correction value that brings the measured value of the non-attention light receiving element close to zero at the time when the reference light is incident on the attention light receiving element. .. In the measurement value acquisition step, the measurement value corrected by the base correction value may be sequentially acquired.

The optical measurement method according to the present invention is an optical measurement method using any of the above linearity correction methods, and when the measurement light is incident on the attention light receiving element, the measured value of the attention light receiving element is measured. Correct based on the first function.

There may be a plurality of the light receiving elements of interest. Further, when the measurement light is incident on each of the light-receiving elements of interest, the output value of the light-receiving element of interest is determined based on one function representing the first function obtained for each of the plurality of light-receiving elements of interest. You may correct it.

The optical measuring device according to the present invention is a storage means for storing correction parameters corresponding to the first function obtained by any of the above linearity correction methods, and when the measurement light is incident on the light receiving element of interest. A correction means for correcting the measured value of the light receiving element of interest by using the correction parameter is included.

It is an overall block diagram of the optical measuring apparatus which concerns on one Embodiment of this invention. It is a schematic diagram of a CMOS linear image sensor. It is a flow chart which shows the calculation method of a correction parameter. It is a flow chart which shows the calculation method of a correction parameter. It is a figure which shows the spectrum of the measured value Si. It is a partially enlarged view of FIG. It is a figure which shows the change of the 1st corrected measurement value Si'with respect to the increase of exposure time t in comparison with ideal straight line Li. It is a figure which shows the relationship between the 1st corrected measurement value Si'and the actual linearity error ei'. It is a figure which shows the fitting to the real linearity error ei' of the function f (Si'). It is a figure which shows the relationship between the 2nd corrected measurement value Si ″ using the function f, and the real linearity error ei ″. It is a figure which shows the change of the actual linearity error ei ″ with respect to the increase of exposure time t. It is a figure which shows the relationship between the 3rd corrected measurement value Si ″ ″ and the actual linearity error ei ″ ″. It is a flow chart which shows the optical measurement method using a correction parameter.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an optical measuring device according to an embodiment of the present invention. The optical measuring device 10 measures the light intensity for each wavelength, that is, the optical spectrum by dispersing the light emitted from the sample such as the light source 11. The optical spectrum may be used directly as, for example, optical characteristic information of the light source 11. When the sample is a thin film, the optical spectrum of the reflected light from the thin film may be used, for example, to calculate the thickness of the thin film.

The light emitted from the sample such as the light source 11 is applied to the slit 12 provided in the optical measuring device 10. The slit 12 has, for example, an elongated rectangular opening. A cut filter 13 is arranged on the back side of the slit 12 as needed. The cut filter 13 blocks light having a wavelength outside the measurement range. The measurement light that has passed through the cut filter 13 reaches the collimating mirror 14. The collimating mirror 14 is, for example, a concave mirror having a constant curvature, reflects the measurement light that has passed through the slit 12 and converts it into parallel light, and irradiates the diffraction grating 15 with the parallel light.

The diffraction grating 15 diffracts each wavelength component of the light emitted from the collimating mirror 14 in a direction corresponding to the wavelength. The diffraction grating 15 is, for example, a reflection type diffraction grating, and a large number of grooves extending in the same direction as the opening of the slit 12 may be provided on the reflection surface. As a result, the diffraction grating 15 reflects each wavelength component of the light emitted from the collimating mirror 14 so that its intensity increases in the direction corresponding to the wavelength.

The focus mirror 16, for example, a concave mirror having a constant curvature, reflects the light of each wavelength component diffracted by the diffraction grating 15 and condenses it on each light receiving element arranged in the CCD linear image sensor 17. As schematically shown in FIG. 2, the CCD linear image sensor 17 includes a plurality of (1024 in this case) light receiving elements 17-0 to 17-1023 arranged at equal intervals in the diffraction direction of the diffraction grating 15. .. Each light receiving element 17-i includes a photodiode that accumulates an electric charge that increases with the intensity and time of the light received, and outputs a value corresponding to the amount of the accumulated electric charge. Wavelengths are assigned to each light receiving element 17-i according to the arrangement order thereof, and the intensity of the light component of the assigned wavelength is output. Here, the subscript i indicates a wavelength channel (0 to 1023).

The output value of each light receiving element 17-i is input to the calculation unit 18 mainly composed of a computer. The calculation unit 18 applies various corrections such as linearity correction to each output value to obtain a measured value of the light intensity of each wavelength component.

The CMOS linear image sensor 17 has a drawback of being inferior in linearity as described above. Therefore, in the optical measuring device 10, various corrections are made to the raw output values of the light receiving elements 17-i of the CMOS linear image sensor 17 to realize linearity. That is, the conversion based on the correction parameter is applied to the raw output value of each light receiving element 17-i and used as the measured value. The measured value thus obtained has so-called linearity, which increases α-fold when the light intensity increases α-fold.

3 and 4 are flow charts showing a method of calculating the linearity correction parameter. Here, the correction of the measured value by the CMOS linear image sensor 17 is 1) the first correction to prevent the measured value from becoming less than zero in the short wavelength region, and 2) the second to realize the linearity in the region where the light intensity is large. Correction 3) It includes three corrections of the third correction that realizes linearity in a region where the light intensity is small. These three corrections are applied in order to the raw output value of each light receiving element 17-i. The processes shown in FIGS. 3 and 4 are executed by a computer such as the arithmetic unit 18.

In order to obtain the correction parameters used for the first correction, the second correction, and the third correction, first, in the optical measuring device 10, each light receiving element 17 of the CMOS linear image sensor 17 is in a state where no light is incident on the inside of the device from the slit 12. The raw output value Ai0 of −i is acquired (S101).

Next, a reference light having a constant light intensity such as white light from a halogen lamp is incident on the inside of the device from the slit 12, and the exposure time t is increased from 0 to tmax, and each light receiving element 17-i of the CMOS linear image sensor 17 is increased. The raw output value Ai of is acquired (S102). When the exposure time t changes by ts from 1 to tmax, the output value Ai of each wavelength channel i includes tmax / ts values (here, tmax = 10000).

Next, the measured value Si, which is the value obtained by subtracting the output value Ai0 from the output value Ai, is calculated (S103). When the exposure time t changes by ts from 1 to tmax, the measured value Si of each wavelength channel i includes tmax / ts.

FIG. 5 is a diagram showing a spectrum of the measured value Si. The horizontal axis corresponds to the wavelength channel i, and the vertical axis corresponds to the measured value Si. Here, four spectra corresponding to the exposure times t = 100, 3000, 6000, and 10000 are shown. As shown in the figure, the measured value Si increases from near zero around wavelength channel i = 200 and decreases to near zero around wavelength channel i = 600. FIG. 6 is an enlarged view showing a portion of wavelength channel i = 0 to 150 in FIG. As shown in FIG. 6, in the region where the wavelength channel i is small (that is, short wavelength), the measured value Si may be smaller than zero. Therefore, here, for each exposure time t, the average value of the measured values Si is calculated for a predetermined number of wavelength channels i (here i = 0 to 9) in which the measured value Si is originally considered to be zero, and the value is set as b. (S104). That is, when the exposure time t changes by ts from 1 to tmax, the correction parameter b (base correction value) includes tmax / ts values. The first corrected measured value Si'is obtained by subtracting the correction parameter b from the measured value Si for each combination of the exposure time t and the wavelength channel i (S105). As will be described later, in order to obtain statistical variation in the first corrected measured value Si', the processes of S102 to S105 are repeated a plurality of times (for example, 100 times) under the same conditions.

Next, the measured value Si'is converted into an actual linearity error ei'. FIG. 7 is a diagram showing a change in the first corrected measured value Si'with respect to an increase in the exposure time t in comparison with the ideal straight line Li. In the figure, a plane having a horizontal axis indicating the exposure time t and a vertical axis indicating the first corrected measurement value Si'is shown. The ideal straight line Li is a point (tmax, Si'max) consisting of a maximum exposure time t = tmax and a value of the first corrected measured value Si'at that time (this value is referred to as Si'max), and an origin (tmax, Si'max). It is a straight line connecting 0,0) and (S106). As shown in the following equation (1), the actual linearity error ei'indicates the ratio of the difference between the ideal straight line Li and the first corrected measured value Si'to the first corrected measured value Si'(). S107).

FIG. 8 is a diagram showing the relationship between the first corrected output value Si'and the actual linearity error ei'. Here, the case of i = 456 is shown as an example. As shown in the figure, as the first corrected output value Si'becomes larger, the actual linearity error ei' becomes smaller. Further, in the region where the first corrected measured value Si'is small, the actual linearity error ei' fluctuates greatly up and down, whereas in the region where the first corrected measured value Si'is large, the actual linearity error ei' Fluctuations are small. Therefore, in the second correction, the linearity of the measured value by the CMOS linear image sensor 17 is improved mainly in the region where the first corrected measured value Si'is large, that is, the region where the value of the exposure time t is large.

Therefore, first, the error Δei'of the actual linearity error ei'is calculated by the following equation (2) (S108). Equation (2) is derived from the well-known law of error propagation. The error Δei'is calculated for each combination of the exposure time t and the first corrected measured value Si'. In the formula (2), ΔSi'and ΔSi'max indicate the sample standard deviations of the first corrected measured values Si'and Si'max. As shown in FIG. 8, the error Δei ′ increases when the exposure time t and the value of the first corrected measured value Si ′ are small, and conversely decreases when the value is large. The error Δei'is an example of the variation amount indicating the variation of the measured value Si', and the variation amount may be obtained by another calculation formula.

Next, a quadratic function f (Si') = C2 × Si'2 + C1 × Si'+ C0 indicating a linearity error is prepared for each wavelength channel i, and f (Si') is set to the actual linearity error ei in each wavelength channel i. 'Fit (S109). The least squares method is used for fitting. As a result, the coefficients C0, C1 and C2 are determined. Here, a quadratic function is adopted as an example of the first function of the present invention, but it goes without saying that it may be another function.

The fitting in S109 may be performed only for the wavelength channel i in which the output value Ai at the exposure time t = tmax is equal to or greater than a predetermined threshold value. In this case, the coefficients C0, C1 and C2 will be determined only for such wavelength channel i.

FIG. 9 is a diagram showing the fitting of the quadratic function f (Si') to the real linearity error ei'. Again, the case of i = 456 is shown as an example. The horizontal axis indicates the measured value Si', and the vertical axis indicates the actual linearity error ei'. The black dots in the figure indicate the measurement points (Si', ei') consisting of the measured value Si'and the actual linearity error ei'. The downward-sloping curve shows the shape of the quadratic function f fitted to these measurement points. The vertical line segment penetrating each black dot indicates an error Δei'. As shown in the figure, the error Δei'is relatively large in the region where the measured value Si'is small (that is, the region where the exposure time t is short). Then, in the region where the error Δei'is large as described above, the degree to which the quadratic function f is fitted to the measurement point is lowered, and conversely, in the region where the error Δei'is small, the degree to which the quadratic function f is fitted to the measurement point is reduced. Make it high. Therefore, the objective function in the least squares method is a weighted sum of the differences between the quadratic function f (Si') and the real linearity error ei', and the reciprocal of the error Δei'is used as this weight. As a result, the quadratic function f (Si') fits better with the actual linearity error ei'in the region where the exposure time t and the value of the first corrected measured value Si'are large.

Next, using the coefficients C0, C1 and C2 determined in S109, the second corrected measured value Si ″ is calculated by the following equation (3) (S110).

In S109, the coefficients C0, C1 and C2 are determined for each wavelength channel i. Therefore, when calculating the second corrected measured value Si ″, the coefficients C0, C1 and C2 determined for the same wavelength channel i are used.

For the sake of simplicity, the average values (representative values) of C0, C1 and C2 are calculated, and in the equation (3), the representative values (that is, each wavelength channel) are prepared for all the wavelength channels i. 1 quadratic function representing a plurality of quadratic functions) may be used in common. In particular, when the fitting of S109 is performed only for the wavelength channel in which the first corrected measurement value Si'at the exposure time t = tmax is equal to or larger than the predetermined threshold value, the wavelength channel for which the fitting of S109 is not performed is not provided. By using the average values of C0, C1 and C2, the second corrected measured value Si'' can be preferably calculated.

Next, for each wavelength channel i, the second corrected measured value Si ″ is converted into an actual linearity error ei ″ (S111). The real linearity error ei ″ can also be calculated by the same equation as the above equation (1).

FIG. 10 is a diagram showing the relationship between the second corrected measured value Si ″ using the function f and the actual linearity error ei ″. Again, the case of i = 456 is shown as an example. As shown in the figure, the actual linearity error ei ″ is a sufficiently small value in the region where the measured value Si ″ is 0.2 or more, and the linearity can be sufficiently achieved in this region. However, the linearity is not sufficient in the region where the measured value Si ″ is less than 0.2, that is, in the region where the exposure time is short. Therefore, in the present embodiment, the exposure time correction is performed as the third correction. The exposure time correction is a correction that increases the measured value Si ″ in a region where the exposure time is short according to the short exposure time. Specifically, the third corrected measured value Si ″ ″ is defined by the following equation (4). That is, the third corrected measured value Si'''' is obtained by multiplying the second corrected measured value Si'' by the fractional function t / (t−d) which is an example of the second function of the present invention. I am trying to do it. Here, d is the corrected exposure time. The larger d, the larger the correction amount. However, in the region where the exposure time t is large, the correction amount becomes small, and the difference between the second corrected measurement value Si ″ and the third corrected measurement value Si ″ becomes small. The second function is not limited to the above fractional function, but is a function that approaches a predetermined value (here, 1) as the exposure time t increases and increases as the exposure time approaches 0, and is a variable parameter. Any function may be adopted as long as the shape changes depending on the above.

Next, as shown in the following equation (5), it is assumed that the third corrected measured value Si ″ is proportional to the exposure time t.

By using the equations (4) and (5), the actual linearity error ei'' corresponding to the second corrected measured value Si'' has the exposure time t having the correction parameter d as in the following equation (6). It is represented as a function g (t).

Next, using the result of S111, the function g (t) is fitted to the measurement point (t, ei ″) (S112). As a result, the correction parameter d is determined. FIG. 11 is a diagram showing this fitting. Again, the case of i = 456 is shown as an example.

Then, using the determined parameter d, the second corrected measured value Si ″ is converted into the third corrected measured value Si ″ by the equation (4) (S113). The correction parameter d is determined for each wavelength channel i in S112. Therefore, for each wavelength channel i, the third corrected measured value Si ″ may be calculated by the equation (4) using the correction parameter d corresponding to the wavelength channel i. Alternatively, the average value of the correction parameter d may be calculated, and the average value may be used in common for all wavelength channels i to calculate the third corrected measurement value Si ″ by the equation (4).

FIG. 12 is a diagram showing the relationship between the third corrected measured value Si ″ ″ and the actual linearity error ei ″ ″ calculated from the measured value Si ″ ″. Again, the case of i = 456 is shown as an example. As shown in the figure, the linearity error ei'''is contained in a sufficiently small value in the entire region of Si'''by the first to third corrections, and sufficient linearity is realized in the entire region. I understand.

Finally, the correction parameters C0, C1 and C2 acquired in Ai0 and S109 of each wavelength channel i acquired in S101, and the correction parameter d acquired in S112 are stored in a memory or the like (S114). These correction parameters are used in optical measurements on the sample.

FIG. 13 is a flow chart for performing optical measurement using the correction parameters saved as described above. First, the slit 12 is irradiated with light emitted from a sample such as a light source 11, and the calculation unit 18 acquires the output value Ai (i = 0 to 1023) of the CMOS linear image sensor 17 (S201). The exposure time ta of the measurement light at this time to the CMOS linear image sensor 17 may be set, and ta may be a value equal to or less than the above tmax and set to a sufficiently large value.

Next, the calculation unit 18 acquires the measured value Si (i = 0 to 1023) by subtracting the correction parameter Ai0 from the Ai acquired in S201 (S202). Further, the average value of the measured values Si is calculated for the wavelength channels i = 0 to 9, and the value is set to b (S203). Then, the first corrected measured value Si'is acquired by subtracting the correction parameter b from the measured value Si (S204).

The calculation unit 18 further applies the above equation (3) to the first corrected measured value Si ′, and acquires the second corrected medullary measured value Si ″ (i = 0 to 1023) (S205). At this time, as the correction parameters C0, C1 and C2, those corresponding to the same wavelength channel i are used as long as they are stored for each wavelength channel i. If a common value (average value) is stored for all wavelength channels, that value is used.

The calculation unit 18 calculates the third corrected measurement value Si ″ from the second corrected measurement value Si ″ by the above equation (4) using the exposure time ta and the correction parameter d (S206). Here, as the correction parameter d, if it is saved for each wavelength channel i, the one corresponding to the same wavelength channel i is used. If a common value (average value) is stored for all wavelength channels, that value is used.

After that, the calculation unit 18 displays, prints, communicates, or the like the third corrected measured value Si ″ calculated in S205 (S207). When the sample is a thin film, the calculation unit 18 may calculate the film thickness using the second corrected measurement value Si ″ ″ calculated in S206. A known algorithm can be used for the calculation of the film thickness.

According to the linearity correction method of the optical measuring device 10 described above, the measured value Si'''' having sufficient linearity by applying the first to third corrections to the output value Si of the CMOS linear image sensor 17. Can be obtained, and a highly accurate optical spectrum can be obtained. Further, using this optical spectrum, the film thickness of the sample and the like can be calculated with high accuracy.

The present invention is not limited to the above embodiment, and various modifications are possible, and it goes without saying that such modifications are also included in the scope of the present invention.

10 Optical measuring device, 11 light source (sample), 12 slits, 13 cut filter, 14 collimated mirror, 15 diffraction grating, 16 focus mirror, 17 CMOS linear image sensor, 17-i (i = 0 to 1023) light receiving element, 18 Calculation unit.

Claims (12)

In the linearity correction method of an optical measuring device equipped with a CMOS linear image sensor,
An exposure step in which a reference light having a constant intensity is sequentially incident on a light receiving element of interest of the CMOS linear image sensor by changing the exposure time.
A measurement value acquisition step for sequentially acquiring the measurement values of the light receiving element of interest, and
An actual linearity error calculation step for sequentially calculating an actual linearity error indicating a difference between a linear value obtained based on the exposure time corresponding to the measured value and the measured value, and
For each of the actual linearity errors, a fitting step for executing the fitting of the first function indicating the first linearity error, and
A linearity correction method characterized by including. In the linearity correction method according to claim 1,
The first function is a quadratic function, which is a linearity correction method for a CMOS linear image sensor. In the linearity correction method according to claim 1 or 2.
In the fitting step, the variable parameters of the first function are determined by the least squares method using an objective function indicating the total amount of the differences between each actual linearity error and the first linearity error.
The objective function includes terms indicating the difference between the first linearity error and the actual linearity error corresponding to each measured value, and these terms are weighted by the amount of variation indicating the variation of each measured value. Be done,
A linearity correction method characterized by this. In the linearity correction method according to claim 3,
A linearity correction method further comprising an exposure time correction step of performing an exposure time correction on the measured value corrected by the first function. In the linearity correction method according to claim 4,
The exposure time correction step is characterized in that the exposure time correction is performed by applying a second function that approaches a predetermined value as the exposure time becomes longer to the measured value corrected by the first function. Linearity correction method. In the linearity correction method according to claim 5,
The linearity correction method, characterized in that the second function is a fractional function. In the linearity correction method according to any one of claims 1 to 6,
The measured value is based on the difference between the first output value of the attention receiving element when the reference light is incident and the second output value of the attention receiving element when the reference light is not incident. A linearity correction method characterized by being acquired. In the linearity correction method according to claim 7,
The fitting step is a linearity correction method for a CMOS linear image sensor, characterized in that the fitting is executed by using the measured value acquired based on the first output value equal to or higher than a predetermined threshold value. In the linearity correction method according to any one of claims 1 to 8.
The CMOS linear image sensor includes a non-attention light receiving element in which no light is incident during the time when the reference light is incident on the attention light receiving element.
The linearity correction method is
Further including a base correction value calculation step of calculating a base correction value that brings the measured value of the non-attention light receiving element close to zero at the time when the reference light is incident on the attention light receiving element.
The linearity correction method, wherein the measured value acquisition step sequentially acquires the measured values corrected by the base correction value. An optical measurement method using the linearity correction method according to any one of claims 1 to 9.
An optical measurement method for correcting a measured value of a light receiving element of interest based on the first function when light is incident on the light receiving element of interest. In the optical measurement method according to claim 10,
There are a plurality of the light receiving elements of interest,
When the measurement light is incident on each of the light receiving elements of interest, the measured value of the light receiving element of interest is corrected based on one function representing the first function obtained for each of the plurality of light receiving elements of interest. , Optical measurement method. A storage means for storing correction parameters corresponding to the first function obtained by the linearity correction method according to any one of claims 1 to 9.
When the measurement light is incident on the attention light receiving element, the correction means for correcting the measured value of the attention light receiving element by using the correction parameter,
An optical measuring device comprising.

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