Wavelength calibration method, device and equipment of spectrometer and readable storage medium

Abstract

The application discloses a wavelength calibration method and device of a spectrometer, electronic equipment and a readable storage medium, and is applied to the technical field of optics. The method comprises the following steps: detecting a standard light source by using a to-be-calibrated spectrometer, and obtaining real wavelength values of a plurality of standard spectral lines and positions of the standard spectral lines on pixels. A wavelength expression of each column of pixels of a CCD is determined according to a light path geometric relation of grating diffraction, two to-be-determined parameters are set, the to-be-determined parameters are determined by selecting a wavelength and a pixel position corresponding relation of two standard spectral lines, and a preliminary corresponding relation between each column of pixels of the CCD and the wavelength is determined. A total deviation amount of other spectral lines of the standard light source is obtained by using the preliminary corresponding relation, a minimum value of the total deviation amount is determined according to a light path geometric parameter variable set according to a non-ideal state in actual construction of the spectrometer, the actual geometric parameters of the light path are corrected, and thus the wavelength calibration of the spectrometer is completed. The application can improve the wavelength calibration accuracy of the spectrometer.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to a wavelength calibration method, apparatus, electronic device, and readable storage medium for a spectrometer. Background Technology

[0002] Spectrometers use dispersive elements to separate the electromagnetic radiation from a radiation source into desired wavelengths or wavelength regions, and measure the intensity at selected wavelengths or by scanning a certain band. As a non-destructive testing technique, it is widely used in various industries. Taking Raman spectrometry as an example, Raman spectroscopy, a spectroscopic technique based on Raman scattering, can reflect the molecular fingerprint spectrum based on the vibrations of chemical bonds in a substance. It is widely used in medicine, food safety, gem identification, and drug detection. Currently, for spectrometers that use grating dispersive spectroscopy and CCD (charge-coupled device) multi-channel detection, theoretically, the geometric relationship between the wavelength and the grating diffraction angle can be calculated or simulated using software. Based on this geometric relationship, the detection wavelength corresponding to each CCD pixel can be determined, and thus the spectrum corresponding to each pixel can be obtained. However, due to limitations in the spectrometer's manufacturing precision, errors in the optical component parameters themselves, and human factors such as installation and debugging, the actual detected wavelength of each pixel deviates significantly from the theoretical value, and the distribution of this deviation is complex. Therefore, it is necessary to calibrate the corresponding wavelengths of each CCD pixel in the early stages of spectrometer setup.

[0003] Related techniques typically begin with calibration using known atomic emission lines. The calibration methods employed include direct linear or polynomial standardization, or correlation between the obtained spectrum and a standard spectrum. While direct linear or polynomial standardization is simple and can minimize overall peak position deviation, it can lead to underfitting (resulting in peak deviation) or overfitting (causing significant errors at edges or in regions with large peak position variations). Methods that reassign and standardize the abscissa based on correlation with a standard spectrum are relatively slow and sometimes exhibit large errors in certain areas.

[0004] Therefore, improving the wavelength calibration accuracy of spectrometers is a technical problem that needs to be solved by professionals in this field. Summary of the Invention

[0005] This application provides a wavelength calibration method, apparatus, electronic device, and readable storage medium for a spectrometer, which can improve the wavelength calibration accuracy of the spectrometer.

[0006] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0007] This application provides a method for wavelength calibration of a spectrometer, including:

[0008] S101, using the spectrometer to be calibrated to detect a standard light source with known emission lines, the true wavelength values ​​of multiple standard spectral lines and the pixel positions of each standard spectral line are obtained;

[0009] S102, based on the optical path geometry relationship of grating diffraction and the ideal values ​​of the target optical path geometry parameters, determine the preliminary correspondence between the CCD columns of pixels and the wavelength according to the real wavelength values ​​of the first and second spectral lines and their pixel positions;

[0010] S103, using the preliminary correspondence, determine the wavelength measurement value corresponding to the pixel where the other standard spectral lines of the standard light source are located, and by minimizing the deviation between the wavelength measurement value of each standard spectral line and the true wavelength value, determine the correction value of the target optical path geometric parameters;

[0011] S104, based on the correction values ​​of the target optical path geometric parameters and the preliminary correspondence, further determine the correspondence between each column of CCD pixels and the wavelength, so as to complete the wavelength calibration of the spectrometer to be calibrated;

[0012] Wherein, the first spectral line and the second spectral line are two standard spectral lines selected from multiple standard spectral lines, and the other spectral lines are the remaining standard spectral lines excluding the first spectral line and the second spectral line.

[0013] Optional, S102 includes:

[0014] Based on the optical path geometry of grating diffraction, according to the true wavelength values ​​of the first and second spectral lines and their pixel positions, under the ideal condition that the offset from the center of the CCD is 0 when the light is perpendicularly incident on the CCD and the distance between the CCD and the focusing lens is equal to the focal length of the focusing lens, the incident angle of the grating and the diffraction angle corresponding to the position perpendicularly incident on the CCD are determined.

[0015] Based on the incident angle and the diffraction angle, a preliminary correspondence between each column of CCD pixels and the wavelength is determined.

[0016] Optional, S102 includes:

[0017] A wavelength calibration formula is pre-constructed based on the optical path geometry of grating diffraction to represent the correspondence between each column of pixels of the CCD and the wavelength; the wavelength calibration formula is:

[0018]

[0019] In the formula, λ nε is the wavelength corresponding to the nth column pixel, n = 1, 2, 3, ..., N, ε is the offset of the light from the center of the CCD when the light is perpendicularly incident on the CCD, f is the distance between the CCD and the focusing lens, θ is the incident angle, d is the grating groove spacing, θ1 is the diffraction angle, N is the total number of CCD pixel columns, and w is the width of the CCD pixel.

[0020] Based on the wavelength calibration relationship, a set of calibration parameter calculation equations is generated;

[0021] Based on the true wavelength values ​​of the first and second spectral lines and their corresponding pixel positions, the incident angle of the grating and the diffraction angle corresponding to the position perpendicular to the CCD are calculated in the calibration parameter calculation equations. The calibration parameter calculation equations are as follows:

[0022]

[0023] In the formula, λ a λ is the true wavelength value of the first spectral line. b N represents the true wavelength value of the second spectral line. a N represents the pixel position of the first spectral line. b The pixel position of the second spectral line is ε0, where ε0 represents the light rays incident perpendicularly on the center of the CCD, ε0 = 0, and f0 represents the focal length of the focusing lens.

[0024] Based on the incident angle, the diffraction angle, and the wavelength calibration formula, the preliminary correspondence between each column of CCD pixels and the wavelength is determined.

[0025] Optional, S103 includes:

[0026] The wavelength measurement values ​​of other standard spectral lines of the standard lamp source are determined using the preliminary correspondence, and the difference between the wavelength measurement values ​​of other standard spectral lines and the true wavelength values ​​is calculated; the wavelength measurement values ​​are represented by the target optical path geometric parameters.

[0027] Calculate the sum of squares of the differences between the measured wavelength values ​​and the true wavelength values ​​of other standard spectral lines, and simultaneously calculate the value of the target optical path geometric parameter when the sum of squares is minimized, as the correction value of the target optical path geometric parameter.

[0028] Optionally, the spectrometer to be calibrated is a Raman spectrometer, and after S104, it further includes:

[0029] Measure the target wavelength of the laser Rayleigh line in the calibrated Raman spectrometer;

[0030] The laser wavelength of the Raman spectrometer is deduced based on the target wavelength value and the corresponding Raman shift.

[0031] Optionally, the spectrometer to be calibrated is a Raman spectrometer, and after S104, it further includes:

[0032] The standard sample was measured using a calibrated Raman spectrometer to obtain the wavelength position of the characteristic spectral peak of the standard sample and the corresponding Raman shift.

[0033] The laser wavelength of the Raman spectrometer is deduced by inversely using the wavelength position and the corresponding Raman shift.

[0034] Optionally, the step of inferring the laser wavelength of the Raman spectrometer based on the wavelength position and the corresponding Raman shift includes:

[0035] The laser wavelength of the Raman spectrometer is calculated using the laser wavelength calculation formula; the laser wavelength calculation formula is:

[0036]

[0037] In the formula, λ s ω is the laser wavelength. R Let λ be the Raman shift. R The wavelength position is given.

[0038] Another aspect of this application provides a wavelength calibration device for a spectrometer, comprising:

[0039] The standard data acquisition module is used to detect a standard light source with known emission lines using a spectrometer to be calibrated, and obtain the true wavelength values ​​of multiple standard spectral lines and the pixel positions of each standard spectral line.

[0040] The preliminary relationship calibration module is used to determine the preliminary correspondence between the CCD pixels and wavelengths based on the optical path geometry relationship of the grating diffraction and the ideal values ​​of the target optical path geometry parameters, according to the true wavelength values ​​of the first and second spectral lines and their pixel positions.

[0041] The optical path correction module is used to determine the wavelength measurement value corresponding to the pixel where other standard spectral lines of the standard light source are located using the preliminary correspondence. By minimizing the deviation between the wavelength measurement value of each standard spectral line and the true wavelength value, the correction value of the target optical path geometric parameters is determined. The first spectral line and the second spectral line are spectral lines selected from multiple standard spectral lines, and the other spectral lines are the standard spectral lines excluding the first spectral line and the second spectral line.

[0042] The wavelength calibration module is used to further determine the correspondence between each column of CCD pixels and the wavelength based on the correction values ​​of the target optical path geometric parameters and the preliminary correspondence, so as to complete the wavelength calibration of the spectrometer to be calibrated.

[0043] This application also provides an electronic device including a processor for executing a computer program stored in a memory to implement the steps of a wavelength calibration method for a spectrometer as described in any of the preceding claims.

[0044] Finally, this application also provides a readable storage medium storing a computer program that, when executed by a processor, implements the steps of the wavelength calibration method for the spectrometer as described in any of the preceding claims.

[0045] The advantages of the technical solution provided in this application are that, based on the grating diffraction principle of the spectrometer, and according to the possible changes and deviations in the optical path structure and optical parameters of each component of the instrument, combined with the optical parameters of known spectral lines, the correspondence between each column of CCD pixels and the wavelength is determined, thereby achieving wavelength calibration of the spectrometer. Since this wavelength calibration method originates from the structural principle of the instrument itself, it can avoid large deviations in certain spectral ranges, solving the problem of large errors in certain areas during the calibration process of related technologies, and effectively improving the accuracy of wavelength calibration. Furthermore, the entire wavelength calibration process is simple and easy to implement, does not require excessive computational resources, and has high wavelength calibration efficiency.

[0046] Furthermore, this application also provides a corresponding implementation device, electronic device, and readable storage medium for the wavelength calibration method of a spectrometer, which further makes the method more practical. The device, electronic device, and readable storage medium have corresponding advantages.

[0047] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 A schematic flowchart illustrating a wavelength calibration method for a spectrometer provided in this application;

[0050] Figure 2 A schematic diagram of the optical path geometry of a spectrometer for an exemplary application scenario provided in this application;

[0051] Figure 3 A structural diagram of a specific embodiment of the wavelength calibration device for the spectrometer provided in this application;

[0052] Figure 4A structural diagram of one specific embodiment of the electronic device provided in this application. Detailed Implementation

[0053] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may include steps or units not listed. Various non-limiting embodiments of this application are described in detail below.

[0055] Please see first. Figure 1 , Figure 1 The present application provides a schematic flowchart of a wavelength calibration method for a spectrometer, which may include the following:

[0056] S101: Using a standard light source with known emission spectral lines detected by a spectrometer to be calibrated, the true wavelength values ​​of multiple standard spectral lines and the pixel positions of each standard spectral line are obtained.

[0057] The spectrometer to be calibrated in this embodiment can be any spectrometer that uses a grating as the dispersive element and employs a CCD multi-channel detection spectrum. In other words, the technical solution provided in this application is applicable to wavelength calibration of a multi-channel spectrometer based on grating dispersive spectrum. The standard lamp source can be any type containing multiple known spectral lines, such as a neon lamp or a mercury lamp; this does not affect the implementation of this application. By detecting the standard lamp source with the spectrometer to be calibrated, the optical parameters of multiple spectral lines can be obtained. The optical parameters include the wavelength of each spectral line and the pixel position of that spectral line. For ease of description, the spectral lines measured by the spectrometer to be calibrated on the standard lamp source are defined as standard spectral lines.

[0058] S102: Based on the optical path geometry relationship of grating diffraction and the ideal values ​​of the target optical path geometry parameters, determine the preliminary correspondence between the CCD columns of pixels and the wavelength according to the true wavelength values ​​of the first and second spectral lines and their pixel positions.

[0059] In this step, please refer to the optical path geometry of grating diffraction. Figure 2As shown in the figure, 21 is a diffraction grating, 22 is a focusing lens, and 23 is a multi-channel detector (CCD). Light is incident on the diffraction grating 21, which projects the light through the focusing lens onto the multi-channel detector (CCD). The angle between the incident light and the direction perpendicular to the diffraction grating is the incident angle of the grating, and the angle between the direction perpendicular to the diffraction grating and the direction perpendicular to the CCD is the diffraction angle. The first spectral line and the second spectral line are two standard spectral lines selected from multiple standard spectral lines. For ease of description, they are defined as the first spectral line and the second spectral line. The actual wavelength values ​​and pixel positions of the first and second spectral lines can be obtained from the previous step. Figure 2 As shown, the true wavelength value of the first spectral line can be λ. a Its corresponding pixel position is N a The true wavelength value of the second spectral line can be λ. b Its corresponding pixel position is N b The target optical path geometric parameters refer to the geometric parameters that change due to actual variations and deviations in certain components within the optical path. For example, when light is incident perpendicularly on a CCD, ideally the light is incident perpendicularly on the center of the CCD, and the offset between the light's incident light and the CCD center is zero. However, in many cases, the offset is not zero, meaning the light is not incident perpendicularly on the center of the CCD. Another example is during optical path adjustment; when the collimation and focusing of the beam are not ideal, the distance between the CCD and the focusing lens is not equal to the focal length of the focusing lens. Accordingly, the target optical path geometric parameters can be the offset of the light's incident position from the CCD center, and the distance between the CCD and the focusing lens. There can be one or more target optical path geometric parameters; those skilled in the art can choose the type and number of these parameters according to the actual situation, and this application does not impose any limitations on this. In this step, based on the geometric relationship of grating diffraction in the spectrometer and relevant optical common sense such as the grating equation, the inherent optical correspondence between each column of CCD pixels and wavelength can be determined. This optical correspondence includes two unknown optical parameters, such as the diffraction angle and the grating incident angle, as well as one or more target optical path geometric parameters. Substituting the true wavelength value of the second spectral line of the first spectral line and the corresponding pixel position into this optical correspondence, and simultaneously taking the ideal values ​​of the target optical path geometric parameters in the optical correspondence, the diffraction angle and the grating incident angle can be calculated. Substituting the diffraction angle and the incident angle into the optical correspondence, the preliminary correspondence between each column of CCD pixels and wavelength can be determined. Since the correspondence between each column of CCD pixels and wavelength determined in this step is calculated using only two specific spectral lines, the first and second spectral lines, and considering the possible variations and deviations of certain components in the optical path, this correspondence may not be precisely applicable to other spectral lines. Therefore, it is called the preliminary correspondence between each column of CCD pixels and wavelength.

[0060] S103: Utilize the preliminary correspondence to determine the wavelength measurement value corresponding to the pixel where other standard spectral lines of the standard light source are located. By minimizing the deviation between the wavelength measurement value of each standard spectral line and the true wavelength value, determine the correction value of the target optical path geometric parameters.

[0061] The other spectral lines in this step are the remaining standard spectral lines among the multiple standard spectral lines of S101 that are not the first or second spectral lines. These other spectral lines can be all other standard spectral lines among the multiple standard spectral lines of S101 that are not the first or second spectral lines, or they can be a subset of the standard spectral lines among the multiple standard spectral lines of S101 that are not the first or second spectral lines. It can be understood that the preliminary correspondence between each column of CCD pixels and wavelength is determined by the optical parameters of the first and second spectral lines. The first and second spectral lines are calibrated, while the remaining spectral lines are uncalibrated. The previous step was to initially calibrate the wavelengths of each channel of the spectrometer detector. This step uses the target optical path geometric parameters in the initially calibrated correspondence as variables within a certain range. It uses the optical parameters of the uncalibrated other spectral lines to determine the relationship between the target optical path geometric parameters and the deviation from the measured wavelength relative to the true wavelength value. It finds the value of the target optical path geometric parameters when the deviation is minimized, which is then used as the correction value for the target optical path geometric parameters.

[0062] S104: Based on the correction values ​​and preliminary correspondence of the target optical path geometric parameters, further determine the correspondence between each column of CCD pixels and the wavelength to complete the wavelength calibration of the spectrometer to be calibrated.

[0063] After determining the preliminary correspondence between the CCD pixels and wavelengths in S102, the target optical path geometric parameters in the preliminary correspondence can be corrected based on S103. The corrected target optical path geometric parameter values ​​are used to replace the target optical path geometric parameters in the preliminary correspondence to obtain the final correspondence between the CCD pixels and wavelengths that can be used as the spectrometer to be calibrated, thus completing the wavelength calibration of the spectrometer to be calibrated.

[0064] The technical solution provided in this application, based on the grating diffraction principle of the spectrometer, determines the correspondence between the CCD pixels and wavelengths according to the possible changes and deviations in the instrument's optical path structure and the optical parameters of each component, combined with the optical parameters of known spectral lines, thereby achieving wavelength calibration of the spectrometer. Since this wavelength calibration method originates from the instrument's inherent structural principles, it avoids large deviations in certain spectral ranges, solving the problem of large errors in certain areas during calibration in related technologies, and effectively improving the accuracy of wavelength calibration. Furthermore, the entire wavelength calibration process is simple and easy to implement, requires minimal computational resources, and is highly efficient.

[0065] It should be noted that there is no strict order of execution for the steps in this application. As long as they conform to a logical order, these steps can be executed simultaneously or in a certain preset order. Figure 1 This is just an illustrative example and does not mean that this is the only possible execution order.

[0066] The above embodiments do not limit how to determine the preliminary correspondence between CCD columns of pixels and wavelengths. This application also provides an efficient method for determining the preliminary correspondence between CCD columns of pixels and wavelengths, which may include the following:

[0067] Based on the optical path geometry of grating diffraction, and according to the true wavelength values ​​of the first and second spectral lines and their pixel positions, under ideal conditions where the offset from the CCD center is 0 when the light is perpendicularly incident on the CCD and the distance between the CCD and the focusing lens is equal to the focal length of the focusing lens, the incident angle of the grating and the diffraction angle corresponding to the perpendicularly incident CCD position are determined. Based on the incident angle and the diffraction angle, the preliminary correspondence between each column of CCD pixels and the wavelength is determined.

[0068] In this embodiment, the optical correspondence between each column of CCD pixels and wavelength can be determined by combining the geometric relationship of grating diffraction of the spectrometer with the grating equation. The incident angle and diffraction angle are used as variables in this optical correspondence. Using the two spectral lines of known wavelengths and the corresponding pixel positions in the CCD channel, under the ideal condition that the offset from the CCD center is 0 when the light is perpendicular to the CCD and the distance between the CCD and the focusing lens is equal to the focal length of the focusing lens, the values ​​of the incident angle and diffraction angle are calculated. Substituting the values ​​of the incident angle and diffraction angle into the optical correspondence, the preliminary correspondence between each column of CCD pixels and wavelength is obtained.

[0069] To further improve wavelength calibration efficiency, this embodiment can also pre-construct a correspondence between each column of CCD pixels and wavelength using grating equations based on the optical path geometry of grating diffraction, thus obtaining the wavelength calibration formula; the wavelength calibration formula can be expressed as:

[0070]

[0071] In the formula, λ n ε is the wavelength corresponding to the nth column pixel, n = 1, 2, 3, ..., N, ε is the offset of the position of the light perpendicularly incident on the CCD from the center of the CCD, f is the distance between the CCD and the focusing lens, θ is the incident angle, d is the grating groove spacing, θ1 is the diffraction angle, N is the total number of CCD pixel columns, and w is the CCD pixel width.

[0072] Based on the wavelength calibration relationship, a set of calibration parameter calculation equations is generated; according to the true wavelength values ​​of the first and second spectral lines and their corresponding pixel positions, the incident angle of the grating and the diffraction angle corresponding to the perpendicularly incident CCD position are calculated in the calibration parameter calculation equations; the set of calibration parameter calculation equations can be expressed as:

[0073]

[0074] In the formula, λ a λ is the true wavelength value of the first spectral line. b N represents the true wavelength value of the second spectral line. a N represents the pixel position of the first spectral line. b The pixel position of the second spectral line is given by ε0, where ε0 = 0 when the light is incident perpendicularly on the center of the CCD, and f0 represents the focal length of the focusing lens.

[0075] In this embodiment, the incident angle and diffraction angle are used as variables in the wavelength calibration formula. The actual wavelength values ​​of the two known wavelength spectral lines and the corresponding pixel positions in the CCD channel are substituted into the wavelength calibration formula to obtain a set of equations. The offset of the light rays perpendicularly incident on the CCD and the CCD center, as well as the distance between the CCD and the focusing lens, are used as the target optical path geometric parameters. When the target optical path geometric parameters are ideal, that is, when the light rays are perpendicularly incident on the CCD at the CCD center and the distance between the CCD and the focusing lens is the focal length of the focusing lens, the two variables, incident angle and diffraction angle, can be calculated by solving the set of equations. The calculated values ​​of incident angle and diffraction angle are substituted into the wavelength calibration formula, and the wavelength calibration formula at this time can represent the preliminary correspondence between the CCD pixels and the wavelength.

[0076] It is understandable that the above preliminary correspondence is based on the accurate calibration of the first and second atomic spectral lines. Considering that the collimation and focusing of the beam during the optical path adjustment process may result in the distance between the CCD and the focusing lens not being equal to the focal length of the focusing lens, and if the perpendicular incident position of the diffracted light is not in the ideal center position, it will cause calibration deviation. Therefore, other spectral lines, i.e., uncalibrated spectral lines, may not be accurate. This embodiment can also use the optical parameters of other uncalibrated spectral lines of the standard lamp source for correction. Based on the above embodiment, the focal length f of the focusing lens and the detector center offset ε in the preliminary correspondence can be set as variables within a certain range. The relationship between these variables and the measurement deviation of other uncalibrated spectral lines is determined using the uncalibrated spectral lines of the standard lamp source. Based on any optimization algorithm, the values ​​corresponding to the focal length f and the detector center offset ε when the measurement deviation is minimized can be found. After substituting the values ​​corresponding to the focal length f and the detector center offset ε into the preliminary correspondence formula, the preliminary correspondence formula becomes one that can accurately represent the correspondence between the nth column pixel of the CCD and the wavelength, that is, the wavelength calibration of the spectrometer is completed.

[0077] As an optional implementation of the above embodiments, while taking into account the calibration accuracy of the spectrometer's wavelength and improving calibration efficiency, this embodiment also provides a simple implementation method for quickly correcting the target optical path geometric parameters, which may include the following:

[0078] The remaining spectral lines that are not the first or second spectral lines in each standard spectral line are unlabeled other spectral lines. For each other spectral line, the wavelength measurement value of the other standard spectral lines of the standard lamp source is determined using the expression of the preliminary correspondence relationship, and the difference between the wavelength measurement value of the other standard spectral lines and the true wavelength value is calculated. The wavelength measurement value is expressed by the target optical path geometric parameters. The sum of squares of the differences between the wavelength measurement values ​​of the other standard spectral lines and the true wavelength values ​​is calculated. At the same time, the value of the target optical path geometric parameters is calculated when the sum of squares is minimized, which is used as the correction value of the target optical path geometric parameters.

[0079] Taking one optional expression of the preliminary correspondence given in the above embodiments as an example, the true wavelength value of each unlabeled spectral line is λ. c , λ d …The measurement wavelength calculated using the preliminary correspondence is… N c For uncalibrated spectral lines λ c The pixel position, N d For uncalibrated spectral lines λ d Pixel position:

[0080]

[0081]

[0082] The sum of squares δ of the differences between the true wavelength and the measured wavelength of each of the other uncalibrated spectral lines can be expressed as:

[0083]

[0084]

[0085] By treating f and ε as variables, and making δ a function of f and ε, we find the values ​​of f and ε corresponding to the minimum value of δ. This gives us the correction values ​​of the target optical path geometry parameters. Substituting the calculated correction values ​​of f and ε into the expression corresponding to the preliminary calibration relationship, we can obtain the wavelength calibration of each column of CCD pixels.

[0086] It is understandable that, except for Raman spectrometers, the horizontal axis unit of other spectrometers is nm. Even if some spectrometers use units such as electron volts, these units do not require further correction and can be directly converted using unit conversion formulas. However, for Raman spectrometers, before use, after wavelength calibration according to any of the above embodiments, Raman shift calibration is also required to measure the accurate wavelength of the Raman-excited laser. This application also provides a Raman shift calibration method, which may include the following:

[0087] As an optional implementation, the spectrometer to be calibrated is a Raman spectrometer. The target wavelength value of the laser Rayleigh line of the calibrated Raman spectrometer is measured. The laser wavelength of the Raman spectrometer is inferred from the target wavelength value and the corresponding Raman shift.

[0088] As another optional implementation method parallel to the above embodiments, the spectrometer to be calibrated is a Raman spectrometer. The standard sample is measured using the calibrated Raman spectrometer to obtain the wavelength position of the characteristic spectral peak of the standard sample and the corresponding Raman shift. The laser wavelength of the Raman spectrometer is deduced based on the wavelength position and the corresponding Raman shift.

[0089] As an optional implementation of this embodiment, to improve calibration efficiency, the laser wavelength of the Raman spectrometer can also be directly calculated using the laser wavelength calculation formula; the laser wavelength calculation formula can be expressed as:

[0090]

[0091] In the formula, λ s Laser wavelength (unit: cm) -1 ), ω R Raman displacement (unit: cm) -1 ), λ R This represents the wavelength position (in nm).

[0092] This application also provides a corresponding apparatus for the wavelength calibration method of a spectrometer, further enhancing the practicality of the method. The apparatus can be described from both a functional module perspective and a hardware perspective. The wavelength calibration apparatus for a spectrometer provided in this application is described below. This apparatus is used to implement the wavelength calibration method for a spectrometer provided in this application. In this embodiment, the wavelength calibration apparatus for a spectrometer may include or be divided into one or more program modules. These one or more program modules are stored in a storage medium and executed by one or more processors to complete the wavelength calibration method for a spectrometer disclosed in Embodiment 1. The program module referred to in this application is a series of computer program instruction segments capable of performing specific functions, which are more suitable than the program itself for describing the execution process of the wavelength calibration apparatus for a spectrometer in the storage medium. The following description will specifically introduce the functions of each program module in this embodiment. The wavelength calibration apparatus for a spectrometer described below can be referred to in correspondence with the wavelength calibration method for a spectrometer described above.

[0093] From the perspective of functional modules, see Figure 3 , Figure 3 A structural diagram of the wavelength calibration device for the spectrometer provided in this application, in one specific embodiment, shows that the device may include:

[0094] The standard data acquisition module 301 is used to detect a standard light source with known emission spectral lines using a spectrometer to be calibrated, and obtain the true wavelength values ​​of multiple standard spectral lines and the pixel positions of each standard spectral line.

[0095] The preliminary relationship calibration module 302 is used to determine the preliminary correspondence between the CCD pixels and wavelengths based on the optical path geometry relationship of the grating diffraction and the ideal values ​​of the target optical path geometry parameters, according to the true wavelength values ​​of the first and second spectral lines and their pixel positions.

[0096] The optical path correction module 303 is used to determine the wavelength measurement value corresponding to the pixel where other standard spectral lines of the standard lamp source are located by using the preliminary correspondence relationship. By minimizing the deviation between the wavelength measurement value of each standard spectral line and the true wavelength value, the correction value of the target optical path geometric parameters is determined. Among them, the first spectral line and the second spectral line are spectral lines selected from multiple standard spectral lines, and the other spectral lines are the standard spectral lines excluding the first spectral line and the second spectral line.

[0097] The wavelength calibration module 304 is used to further determine the correspondence between each column of CCD pixels and the wavelength based on the correction values ​​and preliminary correspondence of the target optical path geometric parameters, so as to complete the wavelength calibration of the spectrometer to be calibrated.

[0098] Optionally, in some embodiments of this example, the preliminary relationship calibration module 302 described above can also be used for:

[0099] Based on the optical path geometry of grating diffraction, and according to the true wavelength values ​​of the first and second spectral lines and their pixel positions, under ideal conditions where the offset from the CCD center is 0 when the light is perpendicularly incident on the CCD and the distance between the CCD and the focusing lens is equal to the focal length of the focusing lens, the incident angle of the grating and the diffraction angle corresponding to the perpendicularly incident CCD position are determined. Based on the incident angle and the diffraction angle, the preliminary correspondence between each column of CCD pixels and the wavelength is determined.

[0100] As an optional implementation of the above embodiments, the preliminary relationship calibration module 302 may be further used for:

[0101] A wavelength calibration formula is pre-constructed based on the optical path geometry of grating diffraction to represent the correspondence between each column of pixels in the CCD and the wavelength; the wavelength calibration formula is:

[0102]

[0103] In the formula, λ n ε is the wavelength corresponding to the nth column pixel, n = 1, 2, 3, ..., N, ε is the offset of the light from the center of the CCD when the light is incident perpendicularly on the CCD, f is the distance between the CCD and the focusing lens, θ is the incident angle, d is the grating groove spacing, θ1 is the diffraction angle, N is the total number of CCD pixel columns, and w is the CCD pixel width.

[0104] Based on the wavelength calibration relationship, a set of equations for calculating calibration parameters is generated.

[0105] Based on the true wavelength values ​​of the first and second spectral lines and their corresponding pixel positions, calculate the incident angle of the grating and the diffraction angle corresponding to the perpendicularly incident CCD position in the calibration parameter calculation equations; the calibration parameter calculation equations are as follows:

[0106]

[0107] In the formula, λ a λ is the true wavelength value of the first spectral line. b N represents the true wavelength value of the second spectral line. a N represents the pixel position of the first spectral line. b The pixel position of the second spectral line is given by ε0, where ε0 represents the light rays incident perpendicularly on the center of the CCD, ε0 = 0, and f0 represents the focal length of the focusing lens.

[0108] Based on the relationship between the incident angle, diffraction angle, and wavelength calibration formula, the preliminary correspondence between each column of CCD pixels and the wavelength is determined.

[0109] Optionally, in some other embodiments of this example, the optical path correction module 303 may be further used to: determine the wavelength measurement values ​​of other standard spectral lines of the standard lamp source using the expression of the preliminary correspondence, and calculate the difference between the wavelength measurement values ​​of other standard spectral lines and the true wavelength values; the wavelength measurement values ​​are represented by the target optical path geometric parameters; calculate the sum of squares of the differences between the wavelength measurement values ​​of other standard spectral lines and the true wavelength values, and simultaneously calculate the value of the target optical path geometric parameters when the sum of squares is minimized, as the correction value of the target optical path geometric parameters.

[0110] Optionally, in other embodiments of this example, the above-mentioned device may further include a Raman shift calibration module for: when the spectrometer to be calibrated is a Raman spectrometer, measuring the target wavelength value of the laser Rayleigh line of the calibrated Raman spectrometer; and inferring the laser wavelength of the Raman spectrometer based on the target wavelength value and the corresponding Raman shift.

[0111] As another implementation method parallel to the above embodiments, the Raman shift calibration module is also used for: when the spectrometer to be calibrated is a Raman spectrometer, obtaining the Raman laser wavelength of the calibrated Raman spectrometer and the wavelength position and corresponding Raman shift of the characteristic spectral peak of the standard sample; and inversely deducing the laser wavelength of the Raman spectrometer based on the wavelength position and the corresponding Raman shift.

[0112] As an optional implementation of the above embodiments, the Raman shift calibration module can further be used to: call the laser wavelength calculation formula to calculate the laser wavelength of the Raman spectrometer; the laser wavelength calculation formula is:

[0113]

[0114] In the formula, λ s ω is the laser wavelength. R For Raman displacement, λ R This represents the wavelength position.

[0115] The functions of each module of the wavelength calibration device of the spectrometer in this application can be specifically implemented according to the methods in the above method embodiments. The specific implementation process can be referred to the relevant descriptions in the above method embodiments, and will not be repeated here.

[0116] As can be seen from the above, this embodiment can improve the wavelength calibration accuracy of the spectrometer.

[0117] The wavelength calibration device for the spectrometer mentioned above is described from the perspective of functional modules. Furthermore, this application also provides an electronic device, which is described from the perspective of hardware. Figure 4 This is a schematic diagram of the structure of the electronic device provided in one embodiment of this application. For example... Figure 4As shown, the electronic device includes a memory 40 for storing a computer program; and a processor 41 for executing the computer program to implement the steps of the wavelength calibration method of the spectrometer as described in any of the above embodiments.

[0118] The processor 41 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 41 may also be a controller, microcontroller, microprocessor, or other data processing chip. The processor 41 may be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor 41 may also include a main processor and a coprocessor. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 41 may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 41 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0119] The memory 40 may include one or more computer-readable storage media, which may be non-transitory. The memory 40 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the memory 40 may be an internal storage unit of an electronic device, such as a server hard drive. In other embodiments, the memory 40 may be an external storage device of an electronic device, such as a plug-in hard drive on a server, a smart media card (SMC), a secure digital card (SD), a flash card, etc. Furthermore, the memory 40 may include both internal and external storage units of the electronic device. The memory 40 can be used not only to store application software and various types of data installed on the electronic device, such as code in the process of executing the wavelength calibration method of the spectrometer, but also to temporarily store data that has been output or will be output. In this embodiment, the memory 40 is used to store at least the following computer program 401, which, after being loaded and executed by the processor 41, is capable of implementing the relevant steps of the wavelength calibration method of the spectrometer disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 40 may also include an operating system 402 and data 403, and the storage method may be temporary storage or permanent storage. The operating system 402 may include Windows, Unix, Linux, etc. The data 403 may include, but is not limited to, data corresponding to the wavelength calibration results of the spectrometer.

[0120] In some embodiments, the aforementioned electronic device may further include a display screen 42, an input / output interface 43, a communication interface 44 (or network interface), a power supply 45, and a communication bus 46. The display screen 42 and input / output interface 43, such as a keyboard, are user interfaces; optional user interfaces may also include standard wired interfaces, wireless interfaces, etc. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen, etc. The display may also be appropriately referred to as a display screen or display unit, used to display information processed in the electronic device and to display a visual user interface. The communication interface 44 may optionally include a wired interface and / or a wireless interface, such as a Wi-Fi interface, a Bluetooth interface, etc., typically used to establish communication connections between the electronic device and other electronic devices. The communication bus 46 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0121] Those skilled in the art will understand that Figure 4 The structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, such as sensors 47 that perform various functions.

[0122] The functions of each functional module of the electronic device described in this application can be specifically implemented according to the methods in the above method embodiments. The specific implementation process can be referred to the relevant descriptions in the above method embodiments, and will not be repeated here.

[0123] As can be seen from the above, this embodiment can improve the wavelength calibration accuracy of the spectrometer.

[0124] It is understood that if the wavelength calibration method of the spectrometer in the above embodiments is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods in the various embodiments of this application. The aforementioned storage medium includes: USB flash drive, mobile hard drive, read-only memory (ROM), random access memory (RAM), electrically erasable programmable ROM, register, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, removable disk, CD-ROM, magnetic disk or optical disk, and other media capable of storing program code.

[0125] Based on this, this application also provides a readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the wavelength calibration method for the spectrometer as described in any of the above embodiments.

[0126] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the hardware disclosed in the embodiments, including devices and electronic equipment, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0127] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0128] The wavelength calibration method, apparatus, electronic device, and readable storage medium of a spectrometer provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method for wavelength calibration of a spectrometer, characterized in that, include: S101, using the spectrometer to be calibrated to detect a standard light source with known emission lines, the true wavelength values ​​of multiple standard spectral lines and the pixel positions of each standard spectral line are obtained; S102, based on the optical path geometry relationship of grating diffraction and the ideal values ​​of the target optical path geometry parameters, determine the preliminary correspondence between the CCD columns of pixels and the wavelength according to the real wavelength values ​​of the first and second spectral lines and their pixel positions; S103, using the preliminary correspondence, determine the wavelength measurement value corresponding to the pixel where the other standard spectral lines of the standard light source are located, and by minimizing the deviation between the wavelength measurement value of each standard spectral line and the true wavelength value, determine the correction value of the target optical path geometric parameters; S104, Based on the correction values ​​of the target optical path geometric parameters and the preliminary correspondence, determine the correspondence between each column of CCD pixels and the wavelength, so as to complete the wavelength calibration of the spectrometer to be calibrated; Wherein, the first spectral line and the second spectral line are two standard spectral lines selected from multiple standard spectral lines, and the other spectral lines are the remaining standard spectral lines excluding the first spectral line and the second spectral line; S102 includes: Based on the optical path geometry of grating diffraction, according to the true wavelength values ​​of the first and second spectral lines and their pixel positions, under the ideal condition that the offset from the center of the CCD is 0 when the light is perpendicularly incident on the CCD and the distance between the CCD and the focusing lens is equal to the focal length of the focusing lens, the incident angle of the grating and the diffraction angle corresponding to the position perpendicularly incident on the CCD are determined. Based on the incident angle and the diffraction angle, a preliminary correspondence between each column of CCD pixels and the wavelength is determined.

2. The wavelength calibration method for a spectrometer according to claim 1, characterized in that, S102 includes: A wavelength calibration formula is pre-constructed based on the optical path geometry of grating diffraction to represent the correspondence between each column of pixels of the CCD and the wavelength; the wavelength calibration formula is: In the formula, The wavelength corresponding to the nth column pixel. n =1, 2, 3, ... N , This is the offset from the center of the CCD when light is incident perpendicularly on it. The distance between the CCD and the focusing lens. Let the incident angle be... The spacing between grating marks. The diffraction angle is... This represents the total number of CCD cell columns. The width of the CCD pixel; Based on the wavelength calibration relationship, a set of calibration parameter calculation equations is generated; Based on the true wavelength values ​​of the first and second spectral lines and their corresponding pixel positions, the incident angle of the grating and the diffraction angle corresponding to the position perpendicular to the CCD are calculated in the calibration parameter calculation equations. The calibration parameter calculation equations are as follows: ； In the formula, This represents the true wavelength value of the first spectral line. This is the true wavelength value of the second spectral line. This represents the pixel position of the first spectral line. This represents the pixel position of the second spectral line. This indicates that the light is incident perpendicularly on the center of the CCD. =0, Indicates the focal length of the focusing lens; Based on the incident angle, the diffraction angle, and the wavelength calibration formula, the preliminary correspondence between each column of CCD pixels and the wavelength is determined.

3. The wavelength calibration method for a spectrometer according to claim 1, characterized in that, S103 includes: The wavelength measurement values ​​of other standard spectral lines of the standard lamp source are determined using the preliminary correspondence, and the difference between the wavelength measurement values ​​of other standard spectral lines and the true wavelength values ​​is calculated; the wavelength measurement values ​​are represented by the target optical path geometric parameters. Calculate the sum of squares of the differences between the measured wavelength values ​​and the true wavelength values ​​of other standard spectral lines, and simultaneously calculate the value of the target optical path geometric parameter when the sum of squares is minimized, as the correction value of the target optical path geometric parameter.

4. The wavelength calibration method for a spectrometer according to any one of claims 1 to 3, characterized in that, The spectrometer to be calibrated is a Raman spectrometer. Following S104, the following is also included: Measure the target wavelength of the laser Rayleigh line in the calibrated Raman spectrometer; The laser wavelength of the Raman spectrometer is deduced based on the target wavelength value and the corresponding Raman shift.

5. The wavelength calibration method for a spectrometer according to any one of claims 1 to 3, characterized in that, The spectrometer to be calibrated is a Raman spectrometer. Following S104, the following is also included: The standard sample was measured using a calibrated Raman spectrometer to obtain the wavelength position of the characteristic spectral peak of the standard sample and the corresponding Raman shift. The laser wavelength of the Raman spectrometer is deduced by inversely using the wavelength position and the corresponding Raman shift.

6. The wavelength calibration method for a spectrometer according to claim 5, characterized in that, The step of inferring the laser wavelength of the Raman spectrometer based on the wavelength position and the corresponding Raman shift includes: The laser wavelength of the Raman spectrometer is calculated using the laser wavelength calculation formula; the laser wavelength calculation formula is: ； In the formula, The laser wavelength is [wavelength]. The Raman shift is... The wavelength position is given.

7. A wavelength calibration apparatus for a spectrometer that implements the method according to any one of claims 1 to 6, characterized in that, include: The standard data acquisition module is used to detect a standard light source with known emission lines using a spectrometer to be calibrated, and obtain the true wavelength values ​​of multiple standard spectral lines and the pixel positions of each standard spectral line. The preliminary relationship calibration module is used to determine the preliminary correspondence between the CCD pixels and wavelengths based on the optical path geometry relationship of the grating diffraction and the ideal values ​​of the target optical path geometry parameters, according to the true wavelength values ​​of the first and second spectral lines and their pixel positions. The optical path correction module is used to determine the wavelength measurement value corresponding to the pixel where other standard spectral lines of the standard light source are located using the preliminary correspondence. By minimizing the deviation between the wavelength measurement value of each standard spectral line and the true wavelength value, the correction value of the target optical path geometric parameters is determined. The first spectral line and the second spectral line are spectral lines selected from multiple standard spectral lines, and the other spectral lines are the standard spectral lines excluding the first spectral line and the second spectral line. The wavelength calibration module is used to determine the correspondence between each column of CCD pixels and wavelength based on the correction values ​​of the target optical path geometric parameters and the preliminary correspondence, so as to complete the wavelength calibration of the spectrometer to be calibrated. The preliminary relationship calibration module is further used to: based on the optical path geometry of grating diffraction, and according to the true wavelength values ​​and pixel positions of the first and second spectral lines, under ideal conditions where the offset from the center of the CCD is 0 when the light is perpendicularly incident on the CCD and the distance between the CCD and the focusing lens is equal to the focal length of the focusing lens, determine the incident angle of the grating and the diffraction angle corresponding to the position perpendicularly incident on the CCD; and determine the preliminary correspondence between each column of pixels of the CCD and the wavelength based on the incident angle and the diffraction angle.

8. An electronic device, characterized in that, It includes a processor and a memory, the processor being used to execute a computer program stored in the memory to implement the steps of the wavelength calibration method of the spectrometer as described in any one of claims 1 to 6.

9. A readable storage medium, characterized in that, The readable storage medium stores a computer program that, when executed by a processor, implements the steps of the wavelength calibration method for the spectrometer as described in any one of claims 1 to 6.

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