A wavelength calibration method and system based on absorbance matching

Abstract

This invention discloses a wavelength calibration method and system based on absorbance matching. The method includes first constructing an optical path for measuring the absorbance of a sample solution; then selecting a standard spectrometer and an instrument to be calibrated; and acquiring the true absorbance of each pixel on both the standard spectrometer and the instrument to be calibrated, following the sample solution absorbance measurement optical path. The method also involves acquiring the wavelength-absorbance data for each pixel on the standard spectrometer; obtaining the equivalent absorbance of a single pixel on the instrument to be calibrated based on multiple pixels on the standard spectrometer; and matching the corresponding wavelength band for each pixel on the instrument to be calibrated using a minimum absorbance deviation matching function based on the true absorbance and equivalent absorbance of the single pixel on the instrument to be calibrated. This method is applicable to wavelength calibration of large pixels, solving the technical problems of low spectral resolution and severely reduced wavelength positioning accuracy caused by using characteristic light sources or narrowband filters for wavelength calibration of large pixels.

Description

Technical Field

[0001] This invention belongs to the field of spectral processing, and specifically relates to a wavelength calibration method and system based on absorbance matching. Background Technology

[0002] A spectrometer uses a dispersive element to separate light of different wavelengths based on their different diffraction angles, and then focuses it sequentially onto different pixels of a photodetector to measure the intensity corresponding to each wavelength. It has wide and crucial applications in many scientific and industrial fields, its core function being to obtain information such as the composition, structure, concentration, or physical state of matter by analyzing the interaction between matter and light (absorption, emission, reflection, transmission, scattering, etc.).

[0003] Wavelength calibration, a crucial component of spectroscopic instruments, primarily establishes a precise correspondence between the physical locations (pixels) on the spectrometer detector and the actual wavelengths of light. Optical simulation design reveals the theoretical wavelength distribution; common calibration methods include using a light source with known characteristic emission lines and measuring the positions of these standard spectral lines on the spectrometer detector to establish a mapping function between "pixel positions" and "known wavelengths"; alternatively, using a specific narrowband filter and measuring the pixel center position after filtering with a known center wavelength can also establish a calibration mapping function.

[0004] In the actual fabrication of spectrophotometers (instruments to be calibrated for wavelength), when using large-sized pixels, it becomes impossible to accurately distinguish the characteristic light source spectral lines and the center wavelength of the narrowband filter. The low spectral resolution severely reduces the wavelength positioning accuracy, resulting in the inability to guarantee the accuracy of wavelength calibration. Summary of the Invention

[0005] To address the problems existing in the background technology, the present invention provides a wavelength calibration method and system based on absorbance matching, which solves the technical problems of low spectral resolution and severely reduced wavelength positioning accuracy caused by wavelength calibration of large pixels using characteristic light sources or narrowband filters.

[0006] The technical solution adopted in this invention is:

[0007] I. A wavelength calibration method based on absorbance matching:

[0008] S1. Construct an optical path for measuring the absorbance of the sample solution by sequentially arranging the light source, double plano-convex lenses, three-section spectral absorption cell, and acquisition device.

[0009] S2. The acquisition device selects a standard spectrometer and a wavelength calibration instrument respectively, and acquires the true absorbance of each pixel on the standard spectrometer and the wavelength calibration instrument according to the optical path for measuring the absorbance of the sample solution.

[0010] S3. Obtain wavelength-absorbance data based on the wavelength and actual absorbance of each pixel on the standard spectrometer.

[0011] S4. A single pixel on the wavelength calibration instrument is equivalent to multiple pixels on the standard spectrometer, thereby obtaining the equivalent absorbance of a single pixel on the wavelength calibration instrument based on the multiple pixels on the standard spectrometer.

[0012] S5. In the wavelength-absorbance data, based on the true absorbance and equivalent absorbance of a single pixel on the instrument to be calibrated, the minimum absorbance deviation matching function is used to match the corresponding wavelength band for each pixel on the instrument to be calibrated, thereby completing the wavelength calibration of the instrument to be calibrated.

[0013] The double plano-convex lens consists of two plano-convex lenses with the same structure, and the flat sides of the two plano-convex lenses are arranged opposite each other.

[0014] The three-section spectral absorption cell is provided with a sample solution area, a closed area, and a reference glass area.

[0015] Step S2 specifically involves:

[0016] S21. Select a standard spectrometer as the acquisition device, and acquire the reference spectrum, sample spectrum and dark spectrum of each pixel on the standard spectrometer according to the optical path for measuring the absorbance of the sample solution. Based on the reference spectrum, sample spectrum and dark spectrum of each pixel, obtain the true absorbance of the corresponding pixel on the standard spectrometer.

[0017] S22. Select the instrument to be calibrated for the wavelength of the sample solution. Obtain the reference spectrum, sample spectrum and dark spectrum of each pixel on the instrument to be calibrated according to the optical path for measuring the absorbance of the sample solution. Obtain the true absorbance of the corresponding pixel on the instrument to be calibrated based on the reference spectrum, sample spectrum and dark spectrum of each pixel, thereby obtaining the true absorbance of all pixels on the instrument to be calibrated.

[0018] The reference spectrum is the spectrum collected by the acquisition device after the light passes through the reference glass region of the three-segment spectral absorption cell; the sample spectrum is the spectrum collected by the acquisition device after the light passes through the sample solution region of the three-segment spectral absorption cell; the dark spectrum is the background spectrum of the acquisition device after the light is blocked by the closed region of the three-segment spectral absorption cell.

[0019] The true absorbance of the i-th pixel on the standard spectrometer and the true absorbance of a single pixel on the wavelength calibration instrument are set according to the following formula:

[0020] A i =-log 10 ((I si -Idi ) / (I ri -I di A = -log 10 ((I s -I d ) / (I r -I i ))

[0021] Among them, A i I represents the true absorbance of the i-th pixel on the standard spectrometer; A represents the true absorbance of a single pixel on the instrument to be calibrated for wavelength; ri I si and I di These represent the reference spectrum, sample spectrum, and dark spectrum acquired by the i-th pixel on the standard spectrometer, respectively; I r I s and I d These represent the reference spectrum, sample spectrum, and dark spectrum acquired by a single pixel on the instrument to be calibrated for wavelength, respectively.

[0022] The equivalent absorbance of a single pixel on the wavelength calibration instrument is set according to the following formula:

[0023] A'=-log 10 (Σ(I 0i ·e -Ai ))+log 10 (ΣI 0i );I 0i =I ri -I di A i =-log 10 ((I si -I di ) / (I ri -I di ))

[0024] Where A' represents the equivalent absorbance of a single pixel on the instrument to be calibrated; i represents the index; A i I represents the true absorbance of the i-th pixel on the standard spectrometer; ri I si and I di These represent the reference spectrum, sample spectrum, and dark spectrum acquired by the i-th pixel on the standard spectrometer, respectively; I 0i This represents the light intensity received by the i-th pixel on the standard spectrometer before the region of the transmitted sample solution is reached.

[0025] The minimum absorbance deviation matching function is set according to the following formula:

[0026] F min =minΣ|A-A'|

[0027] Among them, F min denoted as the minimum absorbance deviation matching function; A represents the true absorbance of a single pixel on the instrument to be calibrated for wavelength; A' represents the equivalent absorbance of a single pixel corresponding to the true absorbance A.

[0028] Step S5 includes: obtaining the corresponding pixel segment on the standard spectrometer for each pixel on the wavelength calibration instrument according to the minimum absorbance deviation matching function; and obtaining the wavelength band of the corresponding pixel on the wavelength calibration instrument since the wavelength of the corresponding pixel segment on the standard spectrometer is known.

[0029] II. A wavelength calibration system employing a wavelength calibration method:

[0030] The sample solution absorbance measurement optical path module mainly consists of a light source, double plano-convex lenses, a three-segment spectral absorption cell, and a data acquisition device arranged sequentially. The true absorbance acquisition module uses a standard spectrometer and the instrument to be calibrated (wavelength calibrated) to acquire the true absorbance of each pixel on both instruments according to the sample solution absorbance measurement optical path. The wavelength-absorbance data acquisition module obtains wavelength-absorbance data based on the wavelength and true absorbance of each pixel on the standard spectrometer. The equivalent absorbance acquisition module treats a single pixel on the instrument to be calibrated as equivalent to multiple pixels on the standard spectrometer, thus acquiring the equivalent absorbance of a single pixel on the instrument to be calibrated based on the multiple pixels on the standard spectrometer. The wavelength calibration module uses the minimum absorbance deviation matching function to match the corresponding wavelength band for each pixel on the instrument to be calibrated, based on the true absorbance and equivalent absorbance of the single pixel in the wavelength-absorbance data, thereby completing the wavelength calibration of the instrument.

[0031] The beneficial effects of this invention are:

[0032] 1. The method of this invention is a novel wavelength calibration method. It uses a standard spectrometer to collect known wavelength and absorbance data as reference calibration data, and uses the instrument to be calibrated to collect sample solution data to obtain data of known absorbance but unknown wavelength. According to the minimum absorbance deviation matching function, the two sets of data are matched for absorbance to obtain the wavelength band corresponding to each pixel of the instrument to be calibrated.

[0033] 2. The method of the present invention is applicable to wavelength calibration of large pixels, and solves the technical problems of low spectral resolution and serious reduction in wavelength positioning accuracy caused by using characteristic light sources or narrowband filters for wavelength calibration of large pixels. Attached Figure Description

[0034] Figure 1 This is a flowchart of the method of the present invention.

[0035] Figure 2 This is a schematic diagram of the optical path for measuring the absorbance of the sample solution in Example 2.

[0036] Figure 3 This is the absorbance map collected by 16 pixels on the wavelength calibration instrument in Example 2.

[0037] Figure 4 This is a schematic diagram of wavelength-absorbance data collected by the standard spectrometer in Example 2.

[0038] Figure 5 The image shows the spectrum of I0 collected by the standard spectrometer in Example 2.

[0039] Figure 6 This is a schematic diagram showing the matching of absorbance collected by the standard spectrometer and absorbance collected by the pixel of the instrument to be calibrated in Example 2.

[0040] Figure 7 This is a schematic diagram of the wavelength calibration results in Example 2.

[0041] In the diagram: 1. Light source; 2. Double plano-convex lens; 3. Three-segment spectral absorption cell; 4. Acquisition device; 5. Standard spectrometer; 6. Instrument for wavelength calibration. Detailed Implementation

[0042] The present invention will now be described in more detail with reference to the accompanying drawings and embodiments. However, the present invention is not limited thereto. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

[0043] Example 1:

[0044] like Figure 1 As shown, the wavelength calibration method based on absorbance matching in this embodiment is implemented according to the following steps:

[0045] S1. Construct an optical path for measuring the absorbance of the sample solution, consisting of a light source 1, a double plano-convex lens 2, a three-segment spectral absorption cell 3, and a collection device 4 arranged sequentially. The light emitted from the light source 1 is focused by the double plano-convex lens 2, passes through the three-segment spectral absorption cell 3, and is finally collected by the collection device 4 at the focal point.

[0046] The double plano-convex lens 2 consists of two plano-convex lenses with identical structures, arranged with their flat sides facing each other. In practice, the light source 1 first passes through the first plano-convex lens 2 to collimate the diverging light, then passes through the second plano-convex lens 2 to focus the parallel light, and finally passes through the three-segment spectral absorption cell 3 to focus the light onto the acquisition device 4.

[0047] The three-section spectral absorption cell 3 is equipped with a sample solution area, a closed area, and a reference glass area. In specific implementation, such as... Figure 2 The sample solution absorbance measurement optical path shown has a three-section spectral absorption cell 3 that can move up and down, allowing light to pass through different areas.

[0048] S2 and the acquisition device 4 select the standard spectrometer 5 and the wavelength calibration instrument 6 respectively, and acquire the true absorbance of each pixel on the standard spectrometer 5 and the wavelength calibration instrument 6 according to the optical path for measuring the absorbance of the sample solution.

[0049] S21. The acquisition device 4 selects the standard spectrometer 5 and acquires the reference spectrum, sample spectrum and dark spectrum of each pixel on the standard spectrometer 5 according to the optical path for measuring the absorbance of the sample solution. Based on the reference spectrum, sample spectrum and dark spectrum acquired by each pixel, the true absorbance of the corresponding pixel on the standard spectrometer 5 is obtained.

[0050] S22. The acquisition device 4 selects the wavelength calibration instrument 6 and acquires the reference spectrum, sample spectrum and dark spectrum of each pixel on the wavelength calibration instrument 6 according to the sample solution absorbance measurement optical path. Based on the reference spectrum, sample spectrum and dark spectrum of each pixel, the true absorbance of the corresponding pixel on the wavelength calibration instrument 6 is obtained, thereby obtaining the true absorbance of all pixels on the wavelength calibration instrument 6.

[0051] The reference spectrum is the spectrum collected by the acquisition device 4 after the light passes through the reference glass region of the three-segment spectral absorption cell 3; the sample spectrum is the spectrum collected by the acquisition device 4 after the light passes through the sample solution region of the three-segment spectral absorption cell 3; and the dark spectrum is the background spectrum of the acquisition device 4 after the light is blocked by the closed region of the three-segment spectral absorption cell 3.

[0052] The true absorbance of the i-th pixel on the standard spectrometer 5 and the true absorbance of a single pixel on the wavelength calibration instrument 6 are set according to the following formula:

[0053] A i =-log 10 ((I si -I di ) / (I ri -I di A = -log 10 ((I s -I d ) / (I r -I i ))

[0054] Among them, A iI represents the true absorbance of the i-th pixel on the standard spectrometer 5; A represents the true absorbance of a single pixel on the wavelength calibration instrument 6; ri I si and I di These represent the reference spectrum, sample spectrum, and dark spectrum acquired by the i-th pixel on the standard spectrometer 5, respectively; I r I s and I d These represent the reference spectrum, sample spectrum, and dark spectrum acquired by a single pixel on the wavelength calibration instrument 6, respectively.

[0055] The true absorbance A of several consecutive pixels on the standard spectrometer 5 i Formation as Figure 6 The curve shown is given, and the wavelength of each pixel is known. The true absorbance A of several consecutive pixels on the wavelength calibration instrument 6 is formed as shown. Figure 6 The step lines shown have an unknown wavelength for each pixel.

[0056] The spectral transmittance of the i-th single pixel on the standard spectrometer 5 is set according to the following formula:

[0057] T i =I i / I 0i ;I i =I si -I di ;I 0i =I ri -I di

[0058] Among them, T i I represents the spectral transmittance of the i-th single pixel on the standard spectrometer 5; 0i I represents the light intensity received by the i-th pixel on the standard spectrometer before the transmitted sample solution region; i This represents the light intensity after the i-th pixel on the standard spectrometer 5 transmits the sample solution region.

[0059] S3. Obtain wavelength-absorbance data based on the wavelength and actual absorbance of each pixel on the standard spectrometer 5.

[0060] S4. A single pixel on the wavelength calibration instrument 6 is equivalent to multiple pixels on the standard spectrometer 5, thereby obtaining the equivalent absorbance of a single pixel on the wavelength calibration instrument 6 based on the multiple pixels on the standard spectrometer 5.

[0061] Specifically, since a single pixel on the wavelength calibration instrument 6 is equivalent to multiple pixels on the standard spectrometer 5 when acquired together, the spectral transmittance of a single pixel on the wavelength calibration instrument 6 can be characterized by multiple pixels on the standard spectrometer 5 using the following formula:

[0062] T'=ΣI i / ΣI 0i =(I 01 ·(I1 / I 01 )+I 02 ·(I1 / I 02 )+…+I 0n ·(I n / I 0n )) / ΣI 0i =(ΣI 0i ·T i ) / ΣI 0i

[0063] I 01 =I r1 -I d1 ;I 02 =I r2 -I d2 ;I 0n =I rn -I dn

[0064] Where T' represents the spectral transmittance of a single pixel on the wavelength calibration instrument 6, obtained by characterizing multiple pixels on the standard spectrometer 5; I 01 I 02 I 0i and I 0n These represent the light intensities of the 1st, 2nd, i, and nth pixels on the standard spectrometer 5 before they receive the transmitted sample solution region; I r1 I r2 and I rn These represent the reference spectra acquired by the 1st, 2nd, and nth pixels on the standard spectrometer 5, respectively; I d1 I d2 and I dn These represent the dark spectra acquired by the 1st, 2nd, and nth pixels on the standard spectrometer 5, respectively; T i This represents the spectral transmittance of the i-th pixel on the standard spectrometer 5.

[0065] According to the general formula for calculating absorbance, T=e -A Transforming the above formula, we obtain the following formula:

[0066] e -A’ =(Σ(I 0i ·e -Ai )) / ΣI 0i

[0067] The equivalent absorbance of a single pixel on the instrument 6 to be calibrated is then set according to the following formula:

[0068] A'=-log10 (Σ(I 0i ·e -Ai ))+log 10 (ΣI 0i )

[0069] I 0i =I ri -I di A i =-log 10 ((I si -I di ) / (I ri -I di ))

[0070] Where A' represents the equivalent absorbance of a single pixel on the wavelength calibration instrument 6; i represents the index; A i I represents the true absorbance of the i-th pixel on the standard spectrometer 5; ri I si and I di These represent the reference spectrum, sample spectrum, and dark spectrum acquired by the i-th pixel on the standard spectrometer 5, respectively; I 0i This represents the light intensity received by the i-th pixel on the standard spectrometer 5 before the region of the transmitted sample solution is reached.

[0071] The equivalent absorbance A' of several consecutive pixels on the wavelength calibration instrument 6 can form with Figure 6 A new step line similar to the step line shown.

[0072] S5. In the wavelength-absorbance data collected by the standard spectrometer 5, the minimum absorbance deviation matching function is used to match the corresponding wavelength band for each pixel on the wavelength calibration instrument 6 according to the true absorbance and equivalent absorbance of a single pixel on the wavelength calibration instrument 6, thereby completing the wavelength calibration of the wavelength calibration instrument 6.

[0073] Step S5 includes: obtaining the corresponding pixel segment on the standard spectrometer 5 for each pixel on the wavelength calibration instrument 6 according to the minimum absorbance deviation matching function; and obtaining the wavelength band of the corresponding pixel on the wavelength calibration instrument 6 since the wavelength of the corresponding pixel segment on the standard spectrometer 5 is known.

[0074] The minimum absorbance deviation matching function is set according to the following formula:

[0075] F min =minΣ|A-A'|

[0076] Among them, F min denoted as the minimum absorbance deviation matching function; A represents the true absorbance of a single pixel on the wavelength calibration instrument 6; A' represents the equivalent absorbance of a single pixel corresponding to the true absorbance A.

[0077] In practice, |A-A'| represents the absolute value of the difference between the true absorbance and the equivalent absorbance of a unit pixel, and minΣ|A-A'| represents the summation of the absolute values ​​of the difference between the true absorbance and the equivalent absorbance of each pixel, and then finding its minimum value. This matches the wavelength of each pixel to the optimal value, thus completing the absorbance matching of all pixels.

[0078] This embodiment also provides a wavelength calibration system, including: a sample solution absorbance measurement optical path module, mainly composed of a light source 1, a double plano-convex lens 2, a three-segment spectral absorption cell 3, and a data acquisition device 4 arranged sequentially; a true absorbance acquisition module, wherein the data acquisition device 4 selects a standard spectrometer 5 and a wavelength calibration instrument 6 respectively, and acquires the true absorbance of each pixel on the standard spectrometer 5 and the wavelength calibration instrument 6 according to the sample solution absorbance measurement optical path; and a wavelength-absorbance data acquisition module, which obtains the wavelength-absorbance data based on the wavelength corresponding to each pixel on the standard spectrometer 5 and the true absorbance. The wavelength-absorbance data acquisition module is used to obtain the equivalent absorbance of a single pixel on the wavelength calibration instrument 6 based on the multiple pixels on the standard spectrometer 5. The wavelength calibration module uses the wavelength-absorbance data acquired by the standard spectrometer 5 to match the corresponding wavelength band for each pixel on the wavelength calibration instrument 6 with the minimum absorbance deviation matching function, based on the true absorbance and equivalent absorbance of a single pixel on the wavelength calibration instrument 6, thereby completing the wavelength calibration of the wavelength calibration instrument 6.

[0079] Example 2:

[0080] This embodiment is implemented using the same methods and steps as in Embodiment 1:

[0081] like Figure 2 The diagram shows the optical path for measuring the absorbance of a sample solution, consisting of a light source 1, a double plano-convex lens 2, a three-segment spectral absorption cell 3, and a data acquisition device 4. The light source 1 is a halogen tungsten lamp. The double plano-convex lens 2 collimates and focuses the light from the filament onto the acquisition point. The sample solution area of ​​the three-segment spectral absorption cell 3 can be made of pure water to calibrate the wavelength-to-be-calibrated instrument 6. The absorbance is then collected by the standard spectrometer 5 and the wavelength-to-be-calibrated instrument 6 (16 pixels) at the acquisition point. Specifically, the sample solution area of ​​the three-segment spectral absorption cell 3 is the shaded area at the bottom, the enclosed area is the black area in the middle, and the reference glass area is the blank area at the top.

[0082] The actual absorbance of each pixel on the standard spectrometer 5 and the wavelength calibration instrument 6 is acquired separately according to the optical path for measuring the absorbance of the sample solution. The wavelength-absorbance data acquisition module obtains wavelength-absorbance data based on the wavelength corresponding to each pixel on the standard spectrometer 5 and the actual absorbance, such as... Figure 4 As shown.

[0083] For the known absorbance of each pixel of the wavelength calibration instrument 6, matching is performed in the wavelength-absorbance data acquired by the standard spectrometer 5 according to the following minimum absorbance deviation matching function:

[0084] F min =minΣ|A-(-log 10 (ΣI 0i ·e -Ai )+log 10 (ΣI 0i ))|

[0085] Where A is the absorbance collected by the pixel on the wavelength calibration instrument 6, as shown in the figure. Figure 3 A i For the absorbance of the sample solution acquired by the standard spectrometer 5, please refer to [reference needed]. Figure 4 I 0i The spectrum is as follows Figure 5 As shown.

[0086] like Figure 6 As shown, the absorbance collected by the standard spectrometer 5 is matched with the absorbance collected by the pixel of the wavelength calibration instrument 6. Matching is performed based on minimizing absorbance deviation, and the optimal matching band [λ] is found for each pixel. i , λ i+1 This means that wavelength calibration can be completed. Figure 6 The numbers 1, 2, 3, ..., N-1 in the lower middle section represent the pixel numbers on the instrument 6 to be calibrated for wavelength.

[0087] like Figure 7 The diagram shows the wavelength calibration results. The best matching band for each pixel to be calibrated is plotted on the absorbance map collected by the standard spectrometer 5. Each band represents a matching region.

[0088] The wavelength calibration results of the instrument 6 to be calibrated are summarized in Table 1:

[0089] Table 1 Summary of Wavelength Calibration Results

[0090]

[0091] There are gaps between the pixels inside the wavelength calibration instrument 6, which is also reflected in the wavelength matching results as well.

[0092] The method of this invention uses a standard spectrometer 5 to collect known wavelength and absorbance data as reference calibration data, and uses the instrument to be calibrated 6 to collect sample solution data to obtain data of known absorbance but unknown wavelength. According to the minimum absorbance deviation matching function, the two sets of data are matched to obtain the wavelength band corresponding to each pixel of the instrument to be calibrated 6. This method is suitable for wavelength calibration of large pixels and solves the technical problems of low spectral resolution and serious reduction in wavelength positioning accuracy caused by wavelength calibration of large pixels using characteristic light sources or narrowband filters.

[0093] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A wavelength calibration method based on absorbance matching, characterized in that, Includes the following steps: S1. Construct a sample solution absorbance measurement optical path by arranging the light source (1), double plano-convex lens (2), three-section spectral absorption cell (3) and acquisition device (4) in sequence. The three-section spectral absorption cell (3) is provided with a sample solution area, a closed area and a reference glass area; S2. The acquisition device (4) is replaced with a standard spectrometer (5) and a wavelength calibration instrument (6) to perform measurements. The actual absorbance of each pixel on the standard spectrometer (5) and the wavelength calibration instrument (6) is collected according to the optical path for measuring the absorbance of the sample solution. Step S2 is as follows: S21. The acquisition device (4) selects the standard spectrometer (5) and acquires the reference spectrum, sample spectrum and dark spectrum of each pixel on the standard spectrometer (5) according to the optical path for measuring the absorbance of the sample solution. Based on the reference spectrum, sample spectrum and dark spectrum of each pixel, the true absorbance of the corresponding pixel on the standard spectrometer (5) is obtained. S22. The acquisition device (4) selects the wavelength calibration instrument (6), and obtains the reference spectrum, sample spectrum and dark spectrum of each pixel on the wavelength calibration instrument (6) according to the sample solution absorbance measurement optical path. Based on the reference spectrum, sample spectrum and dark spectrum of each pixel, the true absorbance of the corresponding pixel on the wavelength calibration instrument (6) is obtained, thereby obtaining the true absorbance of all pixels on the wavelength calibration instrument (6). S3. Obtain wavelength-absorbance data based on the wavelength and actual absorbance of each pixel on the standard spectrometer (5); S4. A single pixel on the wavelength calibration instrument (6) is equivalent to multiple pixels on the standard spectrometer (5), thereby obtaining the equivalent absorbance of a single pixel on the wavelength calibration instrument (6) based on the multiple pixels on the standard spectrometer (5). The equivalent absorbance of a single pixel on the wavelength calibration instrument (6) is set according to the following formula: A’=-log 10 (Σ(I 0i ·e -Ai ))+log 10 (ΣI 0i );I 0i =I ri -I di ;A i =-log 10 ((I si -I di ) / (I ri -I di )) Where A' represents the equivalent absorbance of a single pixel on the wavelength calibration instrument (6); i represents the index; A i I represents the true absorbance of the i-th pixel on the standard spectrometer (5); ri I si and I di These represent the reference spectrum, sample spectrum, and dark spectrum acquired by the i-th pixel on the standard spectrometer (5), respectively; I 0i This represents the light intensity received by the i-th pixel of the standard spectrometer (5) before the region of the transmitted sample solution is reached; S5. In the wavelength-absorbance data, the minimum absorbance deviation matching function is used to match the corresponding wavelength band for each pixel on the wavelength calibration instrument (6) according to the true absorbance and equivalent absorbance of a single pixel on the wavelength calibration instrument (6), thereby completing the wavelength calibration of the wavelength calibration instrument (6). The minimum absorbance deviation matching function is set according to the following formula: F min =minΣ|A-A’| Among them, F min denoted as the minimum absorbance deviation matching function; A represents the true absorbance of a single pixel on the wavelength calibration instrument (6); A' represents the equivalent absorbance of a single pixel corresponding to the true absorbance A.

2. The wavelength calibration method based on absorbance matching according to claim 1, characterized in that: The double plano-convex lens (2) consists of two plano-convex lenses with the same structure, and the flat sides of the two plano-convex lenses are arranged opposite each other.

3. The wavelength calibration method based on absorbance matching according to claim 1, characterized in that: The reference spectrum is the spectrum collected by the acquisition device (4) after the light passes through the reference glass region of the three-segment spectral absorption cell (3); the sample spectrum is the spectrum collected by the acquisition device (4) after the light passes through the sample solution region of the three-segment spectral absorption cell (3); the dark spectrum is the background spectrum of the acquisition device (4) after the light is blocked by the closed region of the three-segment spectral absorption cell (3).

4. The wavelength calibration method based on absorbance matching according to claim 1, characterized in that: The true absorbance of the i-th pixel on the standard spectrometer (5) and the true absorbance of a single pixel on the wavelength calibration instrument (6) are set according to the following formula: A i =-log 10 ((I si -I di ) / (I ri -I di ));A=-log 10 ((I s -I d ) / (I r -I i )) Among them, A i I represents the true absorbance of the i-th pixel on the standard spectrometer (5); A represents the true absorbance of a single pixel on the wavelength calibration instrument (6); ri I si and I di These represent the reference spectrum, sample spectrum, and dark spectrum acquired by the i-th pixel on the standard spectrometer (5), respectively; I r I s and I d These represent the reference spectrum, sample spectrum, and dark spectrum collected by a single pixel on the wavelength calibration instrument (6), respectively.

5. The wavelength calibration method based on absorbance matching according to claim 1, characterized in that, Step S5 includes: The corresponding pixel segment on the standard spectrometer (5) for each pixel on the wavelength calibration instrument (6) is obtained according to the minimum matching function of absorbance deviation. Since the wavelength of the corresponding pixel segment on the standard spectrometer (5) is known, the band of the corresponding pixel on the wavelength calibration instrument (6) is obtained.

6. A wavelength calibration system employing any one of the wavelength calibration methods described in claims 1-5, characterized in that, include: The optical path module for measuring the absorbance of the sample solution is mainly composed of a light source (1), a double plano-convex lens (2), a three-segment spectral absorption cell (3), and a collection device (4) arranged in sequence. The real absorbance acquisition module, the acquisition device (4) selects the standard spectrometer (5) and the wavelength calibration instrument (6) respectively, and acquires the real absorbance of each pixel on the standard spectrometer (5) and the wavelength calibration instrument (6) according to the optical path for measuring the absorbance of the sample solution; The wavelength-absorbance data acquisition module obtains wavelength-absorbance data based on the wavelength and actual absorbance of each pixel on the standard spectrometer (5); The equivalent absorbance acquisition module is used to obtain the equivalent absorbance of a single pixel on the wavelength calibration instrument (6) as a multiple pixel on the standard spectrometer (5) based on the multiple pixels on the standard spectrometer (5). The wavelength calibration module uses the minimum absorbance deviation matching function to match the corresponding wavelength band for each pixel on the wavelength calibration instrument (6) based on the true absorbance and equivalent absorbance of a single pixel on the wavelength calibration instrument (6) in the wavelength-absorbance data, thereby completing the wavelength calibration of the wavelength calibration instrument (6).

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