KR20210058702A - Linearity amendment method of optical measurement apparatus, optical measurement method and optical measurement apparatus - Google Patents

Abstract

The present invention relates to a method of performing linearity correction of an optical measurement device using a CMOS linear image sensor with high precision. A linearity correction method for an optical measurement device provided with a CMOS linear image sensor includes: an exposure step in which a reference light having a constant intensity is sequentially incident on an attention light-receiving element of the CMOS linear image sensor by changing an exposure time; a measured value acquisition step of sequentially acquiring measured values of the light-receiving element; an actual linear error calculation step for sequentially calculating an actual linear error indicating the difference between a linear value obtained on the basis of the exposure time corresponding to the measured value and the measured value; and a fitting step in which fitting of a first function representing a first linear error is performed on each of the actual linear errors.

Description

TECHNICAL FIELD The linearity correction method, optical measurement method, and optical measurement device of an optical measurement device TECHNICAL FIELD

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

Charged-coupled devices (CCD) linear image sensors are sometimes used in optical measuring devices such as multi-channel spectroscopes. Specific wavelength portions of the measurement light spectroscopically incident by the diffraction grating are 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 these light-receiving elements. However, in general, a CCD linear image sensor, although it has the advantage of high sensitivity, tends to be complex and expensive in structure.

Japanese Patent Laid-Open No. Hei 5-15628

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

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

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

In order to solve the above problems, the linearity correction method according to the present invention is, in the linearity correction method of an optical measuring device including a CMOS linear image sensor, the CMOS linear image sensor by varying the exposure time of a reference light having a constant intensity. An exposure step of sequentially entering the light-receiving element of interest, a measurement value acquisition step of sequentially obtaining a measured value of the light-receiving element of interest, a linear value obtained based on the exposure time corresponding to the measured value, and the measurement A real linearity error calculation step for sequentially calculating a real linearity error indicating a difference from the value, and a fitting step for performing fitting of a first function indicating a first linearity error for each of the real linearity errors. It is done.

Here, the first function may be a quadratic function.

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

Further, it may further include an exposure time correction step of performing exposure time correction on the measured value corrected by the first function.

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 increases to the measured value corrected by the first function.

Here, the second function may be a fractional function.

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

Further, in the fitting step, the fitting may be performed using the measured value acquired based on the first output value equal to or greater 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 at a time when the reference light is incident on the light-receiving element of interest. In this case, the linearity correction method further includes a base correction value calculation step of calculating a base correction value that approaches zero the measured value of the non-attention light-receiving element at a time when the reference light is incident on the light-receiving element of interest. You may include it. The measurement value acquisition step may sequentially acquire the measurement values corrected by the base correction value.

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

A plurality of the above-mentioned light-receiving elements may be present. In addition, when measurement light is incident on each of the light-receiving elements of interest, the output value of the light-receiving element of interest may be corrected based on one function representing the first function obtained for each of the plurality of light-receiving elements of interest. do.

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

1 is an overall configuration diagram of an optical measuring device according to an embodiment of the present invention.
2 is a schematic diagram of a CMOS linear image sensor.
3 is a flowchart showing a method of calculating a correction parameter.
4 is a flowchart showing a method of calculating a correction parameter.
5 is a diagram showing a spectrum of a measured value S _i.
6 is a partially enlarged view of FIG. 5.
7 is a diagram illustrating _{a change in a first corrected measurement value S i} ′ with an increase in exposure time t compared with an ideal straight line L _i.
FIG. 8 is a diagram showing a relationship between a first corrected measured value S _i ′ and an actual linearity error e _{i ′.}
9 is a diagram showing fitting of a function f(S _i ') to an actual linearity error e _i'.
Fig. 10 is a diagram showing a relationship between a second corrected measured value S _i ″ using a function f and an actual linearity error e _{i ″.}
11 is a diagram showing a change in _{actual linearity error e i} ″ with an increase in exposure time t.
12 is a diagram showing a relationship between a third corrected measured value S _i ''' and an actual linearity error e _i'''.
13 is a flowchart showing an optical measurement method using correction parameters.

Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

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 light intensity for each wavelength, that is, an optical spectrum, by spectroscopic light emitted from a sample such as the light source 11. The optical spectrum may be used directly as, for example, optical property information of the light source 11. In addition, when the sample is a thin film, the optical spectrum of the reflected light by the thin film may be used, for example, to calculate the thickness of the thin film.

Light emitted from a sample such as the light source 11 is irradiated onto the slit 12 provided in the optical measuring device 10. The slit 12 has, for example, an elongated rectangular opening. A cut-off filter 13 is disposed on the back side of the slit 12 as necessary. The cut-off filter 13 blocks light having a wavelength outside the measurement range. The measurement light passing through the cut-off filter 13 reaches the collimating mirror 14. The collimating mirror 14 is, for example, a concave mirror having a constant curvature, and reflects the measurement light passing through the slit 12 to convert it into parallel light, and irradiates the parallel light to the diffraction grating 15.

The diffraction grating 15 diffracts each wavelength component of light irradiated 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 plurality of grooves extending in the same direction as the opening of the slit 12 may be provided on the reflective surface. Thereby, the diffraction grating 15 reflects each wavelength component of light irradiated from the collimating mirror 14 so that its intensity increases in a direction corresponding to the wavelength.

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

The output value of each light-receiving element 17-i is input to an operation unit 18 mainly configured by a computer. In the calculation unit 18, various corrections, such as linearity correction, are performed on each output value, and the measured value of the light intensity of each wavelength component is obtained.

The CMOS linear image sensor 17 has a drawback in that it is inferior to linearity as described above. Therefore, in the optical measurement device 10, various corrections are made to the unprocessed output values of the respective 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 unprocessed output value of each light-receiving element 17-i to be used as a measured value. The measured value obtained in this way has a so-called linearity that similarly increases by a factor of α when the intensity of light increases by a factor of α.

3 and 4 are flowcharts showing a method of calculating a linearity correction parameter. Here, the correction of the measured value by the CMOS linear image sensor 17 is: 1) the first correction so that the measured value does not become less than 0 in the short wavelength region, and 2) the second correction that realizes linearity in the region with high light intensity. It includes three corrections: correction, and 3) a third correction for realizing linearity in a region with a small light intensity. To the unprocessed output value of each light-receiving element 17-i, these three corrections are sequentially applied. In addition, the processing shown in Figs. 3 and 4 is executed by a computer such as the calculation unit 18 or the like.

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, in a state in which no light is incident inside the device from the slit 12, a CMOS linear image sensor _{The unprocessed output value A i} 0 of each of the light-receiving elements 17-i in (17) is acquired (S101).

Next, reference light of a constant light intensity, such as white light from a halogen lamp, is incident into the device from the slit 12, and the exposure time t is _{increased from 0 to t max} , while each received light of the CMOS linear image sensor 17 _{An unprocessed output value A i} of the element 17-i is acquired (S102). When the exposure time t _{changes from 1 to t max} by ts, the output value A _i of each wavelength channel i includes t _max /ts values (here, t _max =10000).

Next, to calculate the output values A _i a value obtained by subtracting the measured value from the output value 0 S _i A _i (S103). When the exposure time t _{changes from 1 to t max} by ts, the measured value S _i of each wavelength channel i includes t _max /ts values.

5: is a figure which shows the spectrum of the _{measured value S i.} The horizontal axis corresponds to the wavelength channel i, and the vertical axis corresponds to the measured value S _i . Here, four spectra corresponding to exposure times t=100, 3000, 6000, and 10000, respectively, are shown. As shown in the figure, the measured value S _i increases from the vicinity of 0 near the wavelength channel i=200, and decreases from the vicinity of the wavelength channel i=600 to the vicinity of 0. 6 is an enlarged view of a portion of the wavelength channel i = 0 to 150 in FIG. 5. As shown in Fig. 6, in a region in which the wavelength channel i is small (that is, a short wavelength), the measured value S _i may be a value smaller than 0. So, where each exposure time t, the measured value S _i is calculated the average value of the measured value S _i for the wavelength channel i (here, i = 0 to 9) having a predetermined number that looks essentially zero, called the value b, and Yes (S104). That is, when the exposure time t _{changes from 1 to t max} by ts, the correction parameter b (base correction value) includes t _max /ts values. Exposure time for each combination of t and the wavelength channel i, by subtracting the correction parameter b from the measured value S _i, to obtain the first correction completion of measurement value S _i '(S105). In addition, in order to obtain the statistical fluctuation of the first corrected measurement value S _i ′ as described later, the processing of S102 to S105 is repeated a plurality of times (for example, 100 times) under the same conditions.

Converts to the next 'chamber linearity error of e _i, S _i to measure. 7 is a diagram illustrating _{a change in a first corrected measured value S i} ′ with an increase in exposure time t compared with an ideal straight line L _i. In the figure, a plane having a horizontal axis representing the exposure time t and a vertical axis representing _{the first corrected measured value S i'is shown.} The ideal straight line L _i is a point (t _max , S _i ) including the maximum exposure time t = t _max and the value of the first corrected measurement value S _i 'at that time (this value _{is described as S i} ' _{max ).} ' _max ) and the origin (0, 0) is a straight line connecting the (S106). Room linearity error e _i ', the following equation (1), as represented by the above straight line L _i of the first calibration termination measure S _i' represents the percentage of the difference, the first correction completion of measurement value S _i 'of (S107).

8 is a view showing the relationship between the first calibration termination output S _i 'and the actual linearity error e _i'. Here, the case of i=456 is shown as an example. As shown in the figure, as the first corrected output value S _i ′ increases, the actual linearity error e _i ′ decreases. In addition, in an area where the first calibrated measured value S _i 'is small, the real linearity error e _i ' varies greatly up and down, _{whereas in the area where the first calibrated measured value S i} 'is large, the real linearity error e _i The fluctuation of 'is small. Therefore, in the second correction, the linearity of the measured value is improved by the CMOS linear image sensor 17 centering on the region in which _{the first corrected measurement value S i ′ is large, that is, the region in which the value of the exposure time t is large.} .

Therefore, first, it calculates the room linearity error e _i, the error Δe _i, using the equation (2) (S108). Equation (2) is derived from the well-known law of overall error. The error Δe _i ′ is calculated for each combination of the exposure time t and the first corrected measurement value S _{i ′.} In Equation (2), ΔS _i ′ and ΔS _i ′ _max represent the sample standard deviations of the first corrected measured values S _i ′ and S _i ′ _max. As shown in Fig. 8, the error Δe _i ′ increases when the exposure time t or the first corrected measured value S _i ′ is small, and decreases when it is large. In addition, the error Δe _i ′ is an example of the amount of fluctuation representing the fluctuation of the measured value S _i ′, and the amount of fluctuation may be obtained by another calculation formula.

Next, a quadratic function f(S _i ') = C2 x S _i '2 + C1 x S _i '+C0 representing the linearity error is prepared for each wavelength channel i, and in each wavelength channel i, f(S _i ' ) Is fitted to the actual linearity error e _i '(S109). The least squares method is used for fitting. Thereby, 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 other functions may be used.

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

9 is a diagram showing fitting of a quadratic function f(S _i ') to a real linearity error e _i'. Here too, the case of i=456 is shown as an example. The horizontal axis represents the measured value S _i ', and the vertical axis represents the actual linearity error e _i '. The black dots in the drawing indicate measurement points (S _i ′, e _i ′) _{including the measurement values S i} ′ and the actual linearity error e _{i ′.} The curve descending to the right shows the shape of the quadratic function f fitted to these measurement points. In addition, a line segment in the vertical direction crossing each black point represents an _{error Δe i'.} As shown in the figure, in the _{region where the measured value S i} ′ is small (that is, the region where the exposure time t is short), the error Δe _i ′ becomes relatively large. In such a _{region where the error Δe i} ′ is large, the degree to which the quadratic function f is fitted to the measurement point is lowered, and in the _{region where the error Δe i} ′ is small, the degree of fitting the quadratic function f to the measurement point is increased. For this reason, the objective function according to the least square method is a quadratic function f (S _i ') and the actual linearity error e _i' primary weighted sum of, and uses the reciprocal of the error Δe _i 'as the weight. As a result, in a region where the exposure time t or the first corrected measured value S _i'is large, the quadratic function f(S _i ') fits due to the actual linearity error e _i'.

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

In addition, in S109, the coefficients C0, C1, and C2 are determined for each wavelength channel i. For this reason, in the _{case of calculating the second corrected measured value S i} ″, the coefficients C0, C1 and C2 determined for the same wavelength channel i are used.

In addition, for simplicity, each average value (representative value) of C0, C1, and C2 is calculated, and in equation (3), for all wavelength channels i, their representative values (that is, a plurality of quadratic functions prepared for each wavelength channel) are calculated. One representative quadratic function) may be used in common. In particular, when the fitting of S109 is performed only for a wavelength channel in which the first corrected measurement value S _{i 'at the exposure time t = t max} is equal to or greater than a predetermined threshold, for the wavelength channel to which the fitting of S109 is not performed, By using the average values of C0, C1 and C2, the second calibrated measured value S _i '' can be appropriately calculated.

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

Fig. 10 is a diagram showing a relationship between a second corrected measured value S _i ″ using a function f and an actual linearity error e _{i ″.} Here too, the case of i=456 is shown as an example. As shown in the figure, in a _{region in which the measured value S i} '' is 0.2 or more, the actual linearity error e _i '' becomes a sufficiently small value, and linearity can be sufficiently achieved in this region. However, in the region where the measured value S _i '' is less than 0.2, that is, the region in which the exposure time is short, the linearity is not sufficient. Therefore, in this embodiment, exposure time correction is performed as the third correction. In the exposure time correction, it is a correction in which the measured value S _i '' in a region in which the exposure time is short is increased as the time is short. Specifically, the third corrected measured value S _i ''' is defined by the following equation (4). That is, by multiplying the second corrected measured value S _i '' by the fractional function t/(td) which is an example of the second function of the present invention, the third corrected measured value S _i ''' is obtained. . 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 measured value S _i ″ and the third corrected measured value S _i ′'' becomes small. In addition, the second function is not limited to the fractional function, and 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 the shape changes by a variable parameter. As long as it does, you may adopt any function.

Next, as shown in the following equation (5), _{it is assumed that the third corrected measured value S i} ''' is proportional to the exposure time t.

By using Equation (4)(5), the actual linearity error ei'' corresponding to the second corrected measured value Si'' is a function g of the exposure time t with the correction parameter d as shown in the following Equation (6). It is denoted as (t).

Next, using the result of S111, the function g(t) is fitted to the _{measurement point (t, e i ″) (S112).} This determines the correction parameter d. 11 is a diagram showing this fitting. Here too, the case of i=456 is shown as an example.

Then, using the determined parameter d, and converts it into a second calibration termination measure S _i '' the third correction completion of measurement value S _i '''according to the equation (4) (S113). Further, the correction parameter d is determined for each wavelength channel i in S112. For this reason, for each wavelength channel i, using the correction parameter d corresponding to the wavelength channel i, the third corrected measured value S _i ''' may be calculated by Equation (4). Alternatively, the average value of the correction parameter d is calculated, and the average value is commonly used in all wavelength channels i, and the third corrected measured value S _i ''' may be calculated by Equation (4).

Fig. 12 is a diagram showing the relationship between the third corrected measured value Si"' and the actual linearity error e _{i'" calculated therefrom.} Here too, the case of i=456 is shown as an example. As shown in the figure, by the first to third corrections, the _{linearity error e i} ''' is converged to a sufficiently small value in the entire area of _{S i''', and sufficient linearity is realized in the entire area.} You can see that it is done.

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

13 is a flowchart of optical measurement using the correction parameters stored as described above. First, light emitted from a sample such as the light source 11 is irradiated to the slit 12, and the output value A _i (i = 0 to 1023) of the CMOS linear image sensor 17 is obtained by the calculation unit 18 ( S201). La exposure time ta to the case of measurement light CMOS linear image sensor 17 and a, ta is is possible to have a sufficiently large value at a value less than the t _max.

Next, the calculation unit 18 obtains the measured value S _i (i = 0 to 1023) by subtracting the correction parameter A _{i 0 from the A i acquired in S201 (S202). Further, the average value of the measured value S i} is calculated for the wavelength channel i = 0 to 9, and the value is referred to as b (S203). Then, by subtracting the correction parameter b from the measured value S _{i , the first corrected measured value S i} ′ is obtained (S204).

Calculating section 18 In addition, the "number of the second calibration by applying the formula (3) to the measured value S _i '1 calibration termination measure S _i and obtains' (i = 0 to 1023) (S205). At this time, as the correction parameters C0, C1, and C2, if stored for each wavelength channel i, those corresponding to the same wavelength channel i are used. If a common value (average value) is stored in all wavelength channels, that value is used.

The computing unit 18 calculates the exposure time ta, and the correction parameter by using the d, the formula (4), the second calibration termination measure by S _i '' complete a third correction of the measurement value S _i '''( S206). Here, as the correction parameter d, if stored for each wavelength channel i, one corresponding to the same wavelength channel i is used. If a common value (average value) is stored in all wavelength channels, that value is used.

After that, the calculation unit 18 outputs the third corrected measured value S _i ''' calculated in S205 by display, printing, communication, or the like (S207). In addition, when the sample is a thin film, the calculation unit 18 may calculate the film thickness using _{the second corrected measured value S i ′" calculated in S206.} For the calculation of the film thickness, a known algorithm can be used.

According to the linearity correction method of the optical measuring device 10 described above, the first to third corrections are performed on _{the output value S i of the CMOS linear image sensor 17, thereby providing a measurement value S i having sufficient linearity.} Can be obtained, and a high-precision optical spectrum can be obtained. Further, using this optical spectrum, the film thickness of the sample can be calculated with high precision.

In addition, the present invention is not limited to the above embodiments, 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: slit
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: operation unit

Claims (12)

In the linearity correction method of an optical measuring device provided with a CMOS linear image sensor,
An exposure step of sequentially entering a target light receiving element of the CMOS linear image sensor by changing an exposure time of reference light having a constant intensity;
A measurement value acquisition step of sequentially acquiring a measurement value of the light-receiving element of interest;
A real linearity error calculation step of sequentially calculating a linear value obtained based on the exposure time corresponding to the measured value and a real linearity error indicating a difference between the measured value;
A fitting step for performing fitting of a first function representing a first linearity error for each of the above actual linearity errors.
Linearity correction method comprising a. The method of claim 1, wherein the first function is a quadratic function. The variable parameter of the first function according to claim 1 or 2, wherein in the fitting step, the variable parameter of the first function is determined by a least squares method using an objective function representing the total amount of the difference between the respective real linearity errors and the first linearity errors. Decide,
The objective function includes a term representing a difference between the first linearity error and the actual linearity error corresponding to each of the measured values, and the terms are weighted by a variation amount representing the variation of each measured value.
Linearity correction method, characterized in that. The linearity correction method according to claim 3, further comprising an exposure time correction step of performing exposure time correction on the measured value corrected by the first function. The method of claim 4, wherein the exposure time correction step performs the exposure time correction by applying a second function that approaches a predetermined value as the exposure time increases to the measured value corrected by the first function. Linearity correction method, characterized in that. 6. The method of claim 5, wherein the second function is a fractional function. The light-receiving element according to any one of claims 1 to 6, wherein the measured value is a first output value of the light-receiving element of interest when the reference light is incident, and the light-receiving element of interest when the reference light is not incident. Linearity correction method, characterized in that acquired based on the difference between the second output value of. The linearity correction method of a CMOS linear image sensor according to claim 7, wherein the fitting step performs the fitting using the measured value acquired based on the first output value equal to or greater than a predetermined threshold. . The method according to any one of claims 1 to 8, wherein the CMOS linear image sensor comprises a non-attention light-receiving element in which no light is incident at a time when the reference light is incident on the light-receiving element of interest,
The linearity correction method,
Further comprising a base correction value calculation step of calculating a base correction value that approaches zero the measured value of the non-attention light-receiving element at a time when the reference light is incident on the attention-receiving element,
In the measurement value acquisition step, the measurement value corrected by the base correction value is sequentially acquired. It is an optical measurement method using the linearity correction method according to any one of claims 1 to 9,
The optical measurement method, wherein, when measurement light is incident on the light-receiving element of interest, a measured value of the light-receiving element of interest is corrected based on the first function. The method of claim 10, wherein a plurality of the light-receiving elements of interest are present,
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. Storage means for storing a correction parameter corresponding to the first function obtained by the linearity correction method according to any one of claims 1 to 9;
Correction means for correcting a measured value of the light-receiving element of interest using the correction parameter when measurement light is incident on the light-receiving element of interest
Optical measuring device comprising a.

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