An adaptive bandwidth high-precision radiance calibration device and method

Abstract

This invention discloses a high-precision radiance calibration device and method with adaptive bandwidth, belonging to the field of radiometric calibration technology. The device includes a light source module, an automatic bandwidth-adjustable monochromator module, a homogenization and depolarization module, and a standard reference module connected in sequence, as well as a control and data processing module electrically connected to each module. The slit of the automatic bandwidth-adjustable monochromator module is driven by a stepper motor. The control and data processing module has a built-in adaptive algorithm unit, which, combined with real-time feedback from a laser wavelength meter, achieves automated and precise bandwidth adjustment. The method includes parameter input, preprocessing, intelligent bandwidth matching, light source output and homogenization, alternating calibration measurement, and data processing and output steps. It matches the optimal bandwidth based on bandwidth matching criteria and simultaneously adjusts the rotation speed of the diffuse reflector to synergistically suppress interference, polarization, and stray light effects. This invention achieves full-process automation of calibration, significantly shortens the calibration cycle across the entire wavelength band, and is compatible with the calibration of various spectrometers.

Description

Technical Field

[0001] This invention relates to the field of radiation calibration technology, and in particular to a high-precision radiance calibration device and method with adaptive bandwidth. Background Technology

[0002] Radiance calibration is a core component of quantitative measurement in optical remote sensing instruments and space remote sensing payloads. Its accuracy directly determines the reliability of observation data and is widely used in atmospheric environmental monitoring, satellite on-orbit calibration, and other scenarios. The solar reflectance spectrum (350nm-2500nm) is the core operating band of optical remote sensors, and achieving high-precision radiance calibration of remote sensing instruments within this spectral range is of great significance. Existing radiance calibration technologies have significant limitations: traditional halogen tungsten lamps and xenon lamps have narrow spectral coverage (300-2000nm) and low power density, resulting in insufficient calibration signal-to-noise ratio and calibration uncertainty as high as 3%-5%; while tunable lasers have excellent monochromaticity and high power, the coverage of a single tunable laser is limited, ranging from a few nanometers to a few hundred nanometers. Multiple tunable lasers are needed to cover the solar reflectance spectrum, which is not only costly but also complex to operate and maintain, failing to meet operational calibration requirements.

[0003] While the supercontinuum laser and monochromator combination system has solved the problems of wide spectrum and high power density (power density on the order of mW / nm, covering 400-2400nm), key technical shortcomings still exist: First, bandwidth adjustment relies on manual adjustment of the monochromator slit, lacking automated control functions, making it impossible to quickly adapt to the bandwidth requirements of different instruments, and the adjustment accuracy is affected by human operation, resulting in low calibration efficiency; second, there is a research gap in the relationship between bandwidth adjustment and calibration accuracy. Existing technologies generally neglect the theoretical impact of monochromator bandwidth on the radiance calibration results of spectrometer-type devices under test. According to rigorous radiometric formula derivation, for spectrometer-type devices with spectral resolution, their radiance responsivity is essentially the convolution result of their in-band spectral response function and the spectral distribution of the light source. Changes in monochromator bandwidth have little impact on the final integrated radiance calibration result. Due to a lack of theoretical understanding, existing technologies blindly pursue extremely narrow bandwidth or make bandwidth adjustments without theoretical basis, which not only fails to effectively improve accuracy but also introduces unnecessary interference effects, making it difficult to improve the system calibration accuracy. Thirdly, the system has problems such as polarization effect and stray light. The linear polarization degree of the light directly output by the monochromator is relatively high, which requires depolarization through an integrating sphere. However, existing systems do not coordinate the optimization of bandwidth adjustment with depolarization and stray light suppression.

[0004] The prior art CN108680251B provides a subdivision spectral scanning calibration device based on supercontinuum laser and monochromator. This device uses a supercontinuum laser as the illumination source of the monochromator. The laser emitted from the supercontinuum laser is coupled into the entrance slit of the monochromator through a coupling optical path composed of three off-axis parabolic mirrors. Of the monochromatic light output by the monochromator, part of the light is monitored for wavelength and bandwidth in real time by a laser wavelength meter, and the other part of the light enters the decoherence integrating sphere to form a uniform surface light source. The standard radiance detector and the device to be calibrated are switched by an electrically controlled translation stage to achieve alternative radiometric calibration. However, the bandwidth adjustment of this device relies on manual operation of the monochromator slit, lacking an automated control mechanism. It cannot quickly adapt to the channel bandwidth requirements of different remote sensing instruments, and the adjustment accuracy is affected by human operation, resulting in low calibration efficiency. Furthermore, no adaptive matching mechanism between bandwidth and calibration accuracy has been established. Narrow bandwidth is prone to interference effects due to laser coherence, while wide bandwidth reduces monochromaticity. It is impossible to dynamically optimize the bandwidth parameters according to the characteristics of the instrument under test. Moreover, the bandwidth adjustment is not designed in conjunction with polarization suppression, stray light suppression, and interference effect suppression. The linear polarization degree of the monochromator's direct output light is relatively high. Although it can be depolarized by integrating sphere, no optimization scheme linked to bandwidth adjustment has been formed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision radiance calibration device and method with adaptive bandwidth. Based on the physical law that "monochromator bandwidth has little effect on spectrometer calibration results", this invention abandons the traditional bandwidth control strategy and uses intelligent algorithms to collaboratively optimize key parameters such as bandwidth, polarization and stray light. This solves the problems of low efficiency and limited accuracy in existing technologies.

[0006] To achieve the above objectives, the present invention provides a high-precision radiance calibration device with adaptive bandwidth, comprising a light source module, an automatic bandwidth adjustment monochromator module, a uniform light depolarization module, and a standard reference module connected in sequence, and a control and data processing module electrically connected to each of the above modules. The automatic bandwidth adjustment monochromator module includes a monochromator entrance slit, a filter, a monochromator, a monochromator exit slit, a semi-reflective mirror, and a laser wavelength meter. The monochromator entrance slit and the monochromator exit slit are driven by stepper motors. The control and data processing module has a built-in adaptive algorithm unit, which has a built-in bandwidth matching criterion. The laser wavelength meter measures the center wavelength and bandwidth of the monochromator output light in real time and transmits the data to the adaptive algorithm unit. The adaptive algorithm unit drives a stepper motor to adjust the width of the monochromator entrance slit and exit slit according to the bandwidth matching criterion, so as to achieve automatic and precise adjustment of the bandwidth from 0.1nm to 10nm, with an adjustment accuracy of ±0.01nm.

[0007] Preferably, the bandwidth matching criterion is specifically: when the bandwidth of the output light from the automatic bandwidth adjustment monochromator module... Less than the bandwidth of the spectrometer under test At this time, the influence of bandwidth change on the calibration results of the spectrometer under test is ignored; at this time, the bandwidth is dynamically adjusted by driving the stepper motor according to the real-time signal-to-noise ratio of the spectrometer under test, so that the signal-to-noise ratio of the spectrometer under test is stabilized above 1000.

[0008] Preferably, the light source module includes a supercontinuum laser, a first off-axis parabolic mirror, a second off-axis parabolic mirror, and a cylindrical mirror; the supercontinuum laser is used to provide continuous laser output; the first off-axis parabolic mirror, the second off-axis parabolic mirror, and the cylindrical mirror constitute a coupling optical path, and the input optical path of the coupling optical path is connected to the output optical path of the supercontinuum laser; the coupling optical path is used to convert the output light of the supercontinuum laser into a narrow beam and receive it by the monochromator entrance slit.

[0009] Preferably, the optical path trajectory within the automatic bandwidth adjustment monochromator module is as follows: the thin beam is received by the monochromator after passing through the entrance slit and filter; after passing through the exit slit, the semi-reflective mirror splits the output light of the monochromator into two beams; the reflected light from the semi-reflective mirror is received by the laser wavelength meter to measure the center wavelength and bandwidth of the output light of the monochromator; the transmitted light from the semi-reflective mirror is incident on the integrating sphere in the homogenizing and depolarizing module for radiance calibration; and a suitable filter is selected based on the wavelength fed back by the laser wavelength meter to eliminate higher-order diffraction spectra.

[0010] Preferably, the uniform light depolarization module includes an integrating sphere, a rotating diffuse reflector, and a monitoring detector; the rotating diffuse reflector is disposed inside the integrating sphere, and the monitoring detector is disposed on the side wall of the integrating sphere; the inner liner of the integrating sphere and the surface of the rotating diffuse reflector are both coated with a polytetrafluoroethylene diffuse reflective coating. The output light of the automatic bandwidth-adjustable monochromator module is beam-constricted by the first and second lenses and then incident on the rotating diffuse reflector plate through the light inlet of the integrating sphere. The motor drives the rotating diffuse reflector plate to rotate to suppress laser speckle. The monitoring detector monitors the change in the power of the light reflected from the integrating sphere and corrects the output power of the supercontinuum laser in real time.

[0011] Preferably, the standard reference module includes a transfer radiometer and a data acquisition unit; the transfer radiometer is mounted on an electrically controlled displacement platform, which is used to realize the optical path translation of the transfer radiometer and align the optical path of the transfer radiometer with the output port of the spectrometer under test and the uniform light depolarization module. The data acquisition unit receives the electrical signal output by the transmissive radiometer, and the radiance responsivity of the transmissive radiometer is traced back to the standard luminance meter of the National Institute of Metrology. The radiance at the exit of the transmissive radiometer measuring integrating sphere is calculated based on the electrical signal output by the data acquisition unit and the radiance responsivity of the transmissive radiometer.

[0012] Preferably, the control and data processing module is used to coordinate the work of each module and process experimental data. The control and data processing module is connected to the monochromator, laser wavelength meter, monitoring detector, spectrometer under test, electrically controlled displacement platform, data acquisition device, supercontinuum laser and rotating diffuse reflector.

[0013] This invention also provides a high-precision radiance calibration method with adaptive bandwidth, comprising the following steps: S1. Parameter Input: Input the key parameters of the spectrometer under test to the control and data processing module through the local interface of the touch screen and the remote interface of the Ethernet. The key parameters include center wavelength, channel bandwidth, detector type and field of view. S2. Preprocessing: Start all equipment in the calibration device, and establish electrical communication and optical path linkage between each device through the control and data processing module; install the spectrometer under test and the radiometer under test on the electrically controlled displacement platform, and drive the laser target to automatically position the two, so that the optical axes of the radiometer under test and the spectrometer under test coincide with the center of the light output port of the integrating sphere of the uniform light and depolarization module; start the supercontinuum laser and preheat for 30 minutes. The light emitted from the supercontinuum laser is converted into a narrow beam through the coupling optical path and then enters the entrance slit of the monochromator. The light emitted from the monochromator module with automatic bandwidth adjustment enters the rotating diffuse reflection plate inside the integrating sphere; the radiometer measures the light emitted from the integrating sphere and transmits the measurement signal to the control and data processing module, which determines the working status of the calibration device. After the power fluctuation of the supercontinuum laser is better than 0.3%, the calibration device enters the working state. S3, Intelligent Bandwidth Matching: The control and data processing module calls the built-in adaptive algorithm unit to set the center wavelength and initial bandwidth of the monochromator output monochromator module. The light emitted from the monochromator module is reflected by a semi-reflective mirror and then incident on the laser wavelength meter. The laser wavelength meter measures the center wavelength and bandwidth of the emitted light in real time and feeds the signal back to the control and data processing module. Based on the channel bandwidth and real-time signal-to-noise ratio of the spectrometer under test, the control and data processing module drives the stepper motor to automatically adjust the monochromator entrance slit and exit slit to the optimal bandwidth while keeping the center wavelength constant. The laser wavelength meter provides continuous real-time feedback and is calibrated by the control and data processing module to ensure the center wavelength and bandwidth adjustment accuracy is ±0.01nm. S4. Light Source Output and Homogenization: The laser emitted from the supercontinuum laser enters the automatic bandwidth-adjustable monochromator module through a coupling optical path with a coupling efficiency of ≥95%. The automatic bandwidth-adjustable monochromator module outputs monochromatic light at the optimal bandwidth. The beam is then sequentially compressed by a semi-reflective mirror, a first lens, and a second lens. The diameter of the compressed beam is smaller than the diameter of the integrating sphere's entrance, ensuring that all monochromatic light is received by the integrating sphere. The beam is then incident on a rotating diffuser plate through the integrating sphere's entrance, achieving homogenization, depolarization, and interference effect suppression. The rotation speed of the rotating diffuser plate is linked to the output bandwidth of the automatic bandwidth-adjustable monochromator module. A monitoring detector monitors the changes in radiance on the inner wall of the integrating sphere in real time and feeds the signal back to the control and data processing module. The control and data processing module then fine-tunes the output power of the supercontinuum laser to ensure that the light source stability is ≤0.3% / h. S5. Alternating Calibration Measurement: The control and data processing module drives the electrically controlled displacement platform to insert the transmissive radiometer into the optical path of the integrating sphere's output port. The data acquisition unit records the transmissive radiometer's response signal and transmits it to the control and data processing module. The control and data processing module calculates the radiance of the light emitted from the integrating sphere according to the radiance transfer formula. Subsequently, the control and data processing module drives the electrically controlled displacement platform to translate, moving the transmissive radiometer away and aligning the spectrometer under test with the integrating sphere's output port. It collects the output code value of the spectrometer under test and calculates the radiance responsivity of each channel of the spectrometer under test according to the formula. The control and data processing module drives the stepper motor to repeatedly adjust the center wavelength of the automatic bandwidth adjustment monochromator module, performing wavelength scanning in the 400nm-2400nm spectral range. After point-by-point calculation and integration, the absolute radiance responsivity of each channel of the spectrometer under test is obtained. S6. Data Processing and Output: The control and data processing module performs normalized deviation analysis on the measurement data from S5 to verify the validity of the data; it integrates various error sources, including laser stability, radiometer measurement, and bandwidth adjustment, to automatically evaluate the calibration uncertainty and finally output a calibration report containing expanded uncertainty.

[0014] Preferably, in S5, the radiance transfer formula for the light emitted from the integrating sphere is: ; in, To transmit the output current value of the radiometer when measuring the light emitted from the integrating sphere. To transmit the radiance responsivity of the radiometer; The spectrometer under test i The radiance responsivity of the channel to quasi-monochromatic light with wavelength λ is: ; in The wavelength of the monochromator is Time, spectrometer under test i The channel's integral time normalized output code value; The spectrometer under test i The formula for calculating the absolute radiance responsivity of a channel is: ; in, and These are the lower and upper limits of the scanning wavelength for the automatic bandwidth-adjustable monochromator module, respectively. The wavelength adjustment interval for the quasi-monochromatic light output by the automatic bandwidth-adjustable monochromator module.

[0015] Preferably, in S3, the optimal bandwidth is the maximum bandwidth that satisfies the condition that "the output bandwidth of the automatic bandwidth adjustment monochromator module is less than the channel bandwidth of the spectrometer under test" and makes the signal-to-noise ratio of the spectrometer under test reach more than 1000; in S4, the linkage logic between the rotation speed of the rotating diffuse reflector and the output bandwidth of the automatic bandwidth adjustment monochromator module is as follows: the smaller the output bandwidth of the automatic bandwidth adjustment monochromator module, the higher the rotation speed of the rotating diffuse reflector, so as to reduce the influence of light source polarization and non-uniformity.

[0016] Therefore, the present invention employs the above-mentioned adaptive bandwidth high-precision radiance calibration device and method, which has the following beneficial effects: 1) Solved the problem of limited calibration accuracy: By introducing a theoretical model of "minimal influence of bandwidth" as the core criterion, ineffective bandwidth adjustment is eliminated, the signal-to-noise ratio of the spectrometer under test is improved, which improves its measurement accuracy; at the same time, the monochromator bandwidth and the rotation speed of the rotating diffuser are adjusted in a coordinated manner to further suppress the influence of laser interference effect and improve calibration accuracy. 2) Solves the problem of low calibration efficiency: By replacing traditional manual calibration with a fully automated bandwidth adjustment and measurement process, measurement accuracy is improved, operational errors are reduced, and the calibration cycle of the entire band is shortened. 3) Solved the problem of polarization and stray light interference: By optimizing the bandwidth, filter and rotation speed of the diffuse reflector, the residual linear polarization of the output light of the integrating sphere is reduced, the level of spectral stray light suppression is improved, and the calibration accuracy of polarization remote sensors and other equipment is improved.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a high-precision radiance calibration device with adaptive bandwidth according to an embodiment of the present invention; Figure 2 This is a flowchart of the adaptive bandwidth high-precision radiance calibration method according to an embodiment of the present invention; Figure 3 This is the result of the stability verification of the calibration device light source in this embodiment of the invention; Figure 4This invention relates to a test of the effect of monochromator bandwidth on the radiometric calibration results of a spectrometer. Figure Labels 1. Supercontinuum laser; 2. First off-axis parabolic mirror; 3. Second off-axis parabolic mirror; 4. Cylindrical mirror; 5. Monochromator entrance slit; 6. Filter; 7. Monochromator; 8. Monochromator exit slit; 9. Semi-reflective mirror; 10. Laser wavelength meter; 11. First lens; 12. Second lens; 13. Integrating sphere; 14. Rotating diffuse reflector; 15. Monitoring detector; 16. Transmissive radiometer; 17. Data acquisition unit; 18. Electrically controlled displacement platform; 19. Control and data processing module; 20. Spectrometer under test. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] Example 1 like Figure 1 As shown, this embodiment discloses a high-precision radiance calibration device with adaptive bandwidth. The device includes a light source module, an automatic bandwidth-adjustable monochromator module, a uniform light and depolarization module connected in sequence, and a standard reference module corresponding to the optical path of the uniform light and depolarization module. It also includes a control and data processing module 19 electrically connected to each of the above modules. The modules work together to realize the automated and high-precision operation of radiance calibration, which is suitable for the calibration needs of various spectrometers in the 400nm-2400nm spectral range.

[0022] 1) Light source module The light source module includes a supercontinuum laser 1, a first off-axis parabolic mirror 2, a second off-axis parabolic mirror 3, and a cylindrical mirror 4. The supercontinuum laser 1 has a spectral coverage of 400nm-2400nm and a long-term stability of ≤0.3% / h, providing continuous and stable laser output for the entire calibration device. The first off-axis parabolic mirror 2, the second off-axis parabolic mirror 3, and the cylindrical mirror 4 sequentially form a high-efficiency coupling optical path. The input optical path of the coupling optical path is connected to the output optical path of the supercontinuum laser 1, and the output optical path is aligned with the monochromator entrance slit 5 of the automatic bandwidth-adjustable monochromator module. This coupling optical path converts the laser emitted from the supercontinuum laser 1 into a narrow beam, ensuring that the beam is accurately received by the monochromator entrance slit 5.

[0023] 2) Automatic bandwidth adjustment monochromator module The automatic bandwidth-adjustable monochromator module includes a monochromator entrance slit 5, a filter 6, a monochromator 7, a monochromator exit slit 8, a semi-reflective mirror 9, and a laser wavelength meter 10. Both the entrance slit 5 and exit slit 8 are driven by stepper motors, with an electric adjustment range of 0.01mm-3mm, enabling precise control of the slit width. The filter 6, built into the monochromator 7, contains five cutoff filters (350nm, 450nm, 650nm, 800nm, and 1250nm) and one neutral stop, also driven by a stepper motor. It suppresses high-diffraction-order stray light and eliminates interference from higher-order diffraction spectra on calibration results. The laser wavelength meter 10 is used to acquire the center wavelength and bandwidth signal of the output light from the monochromator 7 in real time.

[0024] The optical path of this module is as follows: the thin beam from the light source module enters through the monochromator entrance slit 5, is filtered by the adapter filter of the filter 6, is received by the monochromator 7, and exits through the monochromator exit slit 8. It reaches the semi-reflective mirror 9 and is split into two beams. The reflected light from the semi-reflective mirror 9 is connected to the light inlet of the laser wavelength meter 10. The laser wavelength meter 10 measures the wavelength and bandwidth of the output light in real time and transmits the measurement electrical signal to the control and data processing module 19 in real time. The transmitted light from the semi-reflective mirror 9 is the calibration working light. The optical path is connected to the subsequent uniform light and depolarization module for radiance calibration.

[0025] The control and data processing module 19 has a built-in adaptive algorithm unit. This unit pre-stores bandwidth matching criteria. After the measurement signal from the laser wavelength meter 10 is transmitted to the adaptive algorithm unit, the algorithm unit drives the stepper motor to synchronously adjust the width of the monochromator entrance slit 5 and the monochromator exit slit 8 according to the bandwidth matching criteria, so as to realize the automatic and precise adjustment of the bandwidth from 0.1nm to 10nm with an adjustment accuracy of ±0.01nm. No manual intervention is required, which greatly improves the efficiency and accuracy of bandwidth adjustment.

[0026] 3) Uniform light and polarization elimination module The homogenization and depolarization module includes an integrating sphere 13, a rotating diffuse reflector 14, and a monitoring detector 15. The integrating sphere 13 is an anticoherence integrating sphere. The output light of the automatic bandwidth adjustment monochromator module is compressed by the first lens 11 and the second lens 12 and then enters the interior of the integrating sphere 13 through the light inlet. The diameter of the compressed beam is smaller than the diameter of the light inlet of the integrating sphere 13, ensuring that all monochromatic light is received by the integrating sphere 13 and avoiding light energy loss.

[0027] The rotating diffuse reflector 14 is disposed inside the integrating sphere 13 and is driven to rotate by a DC geared motor. The inner liner of the integrating sphere 13 and the surface of the rotating diffuse reflector 14 are both coated with a polytetrafluoroethylene diffuse reflective coating. The reflectivity of this coating is ≥0.96 in the 400nm-2500nm wavelength band. During the rotation of the rotating diffuse reflector 14, the incident light can be dynamically scattered, effectively suppressing laser speckle and interference effects, while achieving light homogenization and depolarization. The inner wall of the integrating sphere 13 is also provided with a polytetrafluoroethylene coated baffle to block the primary reflected light and further improve the light homogenization effect.

[0028] The monitoring detector 15 is installed on the side wall of the integrating sphere 13 to monitor the change in reflected light power inside the integrating sphere 13 in real time and feed the monitoring electrical signal back to the control and data processing module 19. The control and data processing module 19 finely adjusts the output power of the supercontinuum laser 1 according to the monitoring signal to ensure that the light source stability of the entire calibration device is ≤0.3% / h.

[0029] 4) Standard Reference Module The standard reference module includes a radiometer 16, a data acquisition unit 17, and an electrically controlled displacement platform 18. The radiometer 16 is fixedly mounted on the electrically controlled displacement platform 18, which is electrically connected to the control and data processing module 19. The control and data processing module 19 drives the radiometer 16 to perform translation, thereby enabling the radiometer 16 to complete the optical path switching. This allows the radiometer 16 and the spectrometer under test 20 to be precisely aligned with the optical path of the light outlet of the integrating sphere 13, achieving automatic alternating measurement between the two.

[0030] The radiometer 16 measures the entire spectral range of 400-2500 nm, and its radiance responsivity is traceable to the standard luminance meter of the National Institute of Metrology. Its single-wavelength radiance measurement uncertainty is better than 0.5%, providing a precise standard reference for radiance calibration. The signal input terminal of the data acquisition unit 17 is electrically connected to the radiometer 16, and the signal output terminal is electrically connected to the control and data processing module 19. This unit is used to acquire the output electrical signal of the radiometer 16 when measuring the emitted light from the integrating sphere 13, and transmit the signal to the control and data processing module 19, providing raw data for radiance calculation.

[0031] 5) Control and data processing module The control and data processing module 19 is the core control unit of the entire calibration device. It has integrated control software developed on the LabVIEW platform, which supports local operation on the touch screen and remote operation via Ethernet, and can realize batch parameter import and remote calibration control.

[0032] The signal input terminal of this module is electrically connected to the laser wavelength meter 10, the monitoring detector 15, the data acquisition unit 17, and the spectrometer under test 20, and is used to receive real-time measurement and feedback signals from each module; the signal output terminal is electrically connected to the supercontinuum laser 1, the rotating diffuse reflector 14, the monochromator 7, and the electrically controlled displacement platform 18, and is used to send control commands to each module to coordinate the synchronous operation of the light source module, the automatic bandwidth adjustment monochromator module, the uniform light and depolarization module, and the standard reference module.

[0033] Meanwhile, the control and data processing module 19 has a built-in radiance transfer formula and calibration uncertainty evaluation model. Based on the collected data, it automatically calculates the radiance of the emitted light from the integrating sphere and the absolute radiance response of the spectrometer under test 20, and automatically evaluates the calibration uncertainty. Finally, it outputs a complete calibration report including expanded uncertainty.

[0034] Example 2 This embodiment discloses a high-precision radiance calibration method based on the adaptive bandwidth of the device described in Embodiment 1, combined with... Figure 2 As shown, the method includes the following steps: S1. Parameter Input: Key parameters of the spectrometer 20 under test are input to the control and data processing module 19 through the local touch screen interface and the Ethernet remote interface. Key parameters include center wavelength, channel bandwidth, detector type, and field of view. The adaptive algorithm unit of the control and data processing module 19 will provide a basis for judgment for subsequent intelligent bandwidth matching based on the above parameters.

[0035] S2, Preprocessing: S21. Start all equipment of the calibration device. The control and data processing module 19 establishes electrical communication and optical path linkage between all equipment such as the supercontinuum laser 1, stepper motor, laser wavelength meter 10, and electrically controlled displacement platform 18 to ensure timely response and synchronous coordination of each module.

[0036] S22. The spectrometer under test 20 and the radiometer 16 are both mounted on the electrically controlled displacement platform 18. The control and data processing module 19 drives the laser target to automatically position the two instruments, so that the optical axes of the radiometer 16 and the spectrometer under test 20 coincide with the center of the light outlet of the integrating sphere 13. The positioning error is better than 0.1mm, avoiding calibration errors caused by optical path offset.

[0037] S23. Start the supercontinuum laser 1 and preheat for 30 minutes. The light emitted from the supercontinuum laser 1 is converted into a narrow beam through the coupling optical path formed by the first off-axis parabolic mirror 2, the second off-axis parabolic mirror 3, and the cylindrical mirror 4, and then incident on the monochromator entrance slit 5. After being processed by the automatic bandwidth-adjustable monochromator module, the emitted light is incident on the rotating diffuse reflection plate 14 inside the integrating sphere 13.

[0038] S24, the control and data processing module 19 drives the electrically controlled displacement platform 18 to insert the transmissive radiometer 16 into the optical path of the integrating sphere 13's output port; the transmissive radiometer 16 measures the emitted light from the integrating sphere 13, and the measurement signal is transmitted to the control and data processing module 19 via the data acquisition unit 17 to determine the working status of the calibration device. After the supercontinuum laser's optical power fluctuation is better than 0.3%, the calibration device enters the working state.

[0039] S3, Intelligent Bandwidth Matching: S31, the control and data processing module 19 calls the built-in adaptive algorithm unit to set the center wavelength and initial bandwidth of the monochromator output monochromator module.

[0040] S32. The light emitted from the automatic bandwidth adjustment monochromator module is reflected by the semi-reflective lens 9 and then incident on the laser wavelength meter 10. The laser wavelength meter 10 measures the center wavelength and bandwidth of the emitted light in real time and feeds the signal back to the control and data processing module 19.

[0041] S33, the control and data processing module 19, based on the channel bandwidth and real-time signal-to-noise ratio of the spectrometer under test 20, drives the stepper motor to automatically adjust the monochromator entrance slit 5 and monochromator exit slit 8 to the optimal bandwidth while keeping the center wavelength constant. The laser wavelength meter 10 provides continuous real-time feedback and is calibrated by the control and data processing module 19 to ensure that the center wavelength and bandwidth adjustment accuracy is ±0.01nm.

[0042] Specifically, the optimal bandwidth matching criterion is: when the bandwidth of the output light from the automatic bandwidth adjustment monochromator module... Less than 20 bandwidth of the spectrometer under test Furthermore, it enables the signal-to-noise ratio of the spectrometer under test 20 to reach a maximum bandwidth of over 1000. The theoretical basis for this criterion is that when... < At the same time, the influence of bandwidth variation on the calibration results of the spectrometer 20 under test is negligible. At the same time, selecting the maximum bandwidth that meets the signal-to-noise ratio requirements can improve the light intensity and further ensure the calibration accuracy.

[0043] S4. Light Source Output and Homogenization: S41. The laser emitted from the supercontinuum laser 1 enters the automatic bandwidth adjustment monochromator module through the coupling optical path with a coupling efficiency of ≥95%. The automatic bandwidth adjustment monochromator module outputs monochromatic light at the optimal bandwidth, which is then sequentially compressed by the semi-reflective lens 9, the first lens 11, and the second lens 12.

[0044] S42. The diameter of the beam after beam contraction is smaller than the diameter of the entrance port of the integrating sphere 13, ensuring that all monochromatic light is received by the integrating sphere 13. The beam is incident from the entrance port of the integrating sphere 13 to the rotating diffuse reflector 14, achieving uniform light, depolarization and suppression of interference effects. The rotation speed of the rotating diffuse reflector 14 is linked to the output bandwidth of the automatic bandwidth adjustment monochromator module. The linkage logic is: the smaller the output bandwidth of the automatic bandwidth adjustment monochromator module, the higher the rotation speed of the rotating diffuse reflector 14, in order to reduce the influence of light source polarization and non-uniformity.

[0045] S43, the monitoring detector 15 monitors the change in radiance of the inner wall of the integrating sphere 13 in real time and feeds the signal back to the control and data processing module 19. The control and data processing module 19 then fine-tunes the output power of the supercontinuum laser 1 to ensure that the light source stability is ≤0.3% / h.

[0046] S5, Alternating calibration measurement: S51, the control and data processing module 19 drives the electrically controlled displacement platform 18 to cut the radiometer 16 into the optical path of the light outlet of the integrating sphere 13. The data acquisition unit 17 records the response signal of the radiometer 16 and transmits it to the control and data processing module 19. The control and data processing module 19 calculates the radiance of the light emitted from the integrating sphere 13 according to the radiance transfer formula. The formula for the radiance transfer of the light emitted from the integrating sphere is: ; in, To transmit the output current value of the radiometer 16 when measuring the emitted light from the integrating sphere 13, To transmit the radiance responsivity of radiometer 16.

[0047] S52, the control and data processing module 19 drives the electrically controlled displacement platform 18 to translate, move the transradiometer 16 away and align the spectrometer under test 20 with the light outlet of the integrating sphere 13, collect the output code value of the spectrometer under test 20, and calculate the radiance responsivity of each channel of the spectrometer under test according to the formula. The 20th spectrometer under test i The radiance responsivity of the channel to quasi-monochromatic light with wavelength λ is: ; in For the monochromator, the wavelength is 7 Time, spectrometer under test 20th i The channel's integral time normalized output code value.

[0048] S53, the control and data processing module 19 drives the stepper motor, repeatedly adjusts the center wavelength of the automatic bandwidth adjustment monochromator module, performs wavelength scanning in the 400nm-2400nm spectral range, calculates point by point and integrates to obtain the absolute radiance responsivity of each channel of the spectrometer under test 20. The 20th spectrometer under test i The formula for calculating the absolute radiance responsivity of a channel is: ; in, and These are the lower and upper limits of the scanning wavelength for the automatic bandwidth-adjustable monochromator module, respectively. The wavelength adjustment interval for the quasi-monochromatic light output by the automatic bandwidth-adjustable monochromator module.

[0049] S6. Data Processing and Output: The control and data processing module 19 performs normalized deviation analysis on the measurement data of S5 to verify the validity of the data; it integrates various error sources, including the stability of the supercontinuum laser 1, the measurement of the radiometer 16, and the bandwidth adjustment, to automatically evaluate the calibration uncertainty and finally output a calibration report containing expanded uncertainty.

[0050] The theoretical models upon which S3 and S5 are based are as follows. The following derivation process is only used to help understand the optimal bandwidth matching criterion in S3 and the calculation formulas in S5.

[0051] Assume the center wavelength of the monochromator output light is Bandwidth is Then the monochromator calibrates the spectrometer. The radiance responsivity of a channel can be expressed by the following formula: (1) In the above formula Indicates the monochromator calibration spectrometer Radiance responsivity of the channel Indicates the output center wavelength of the monochromator ,bandwidth The radiance function of quasi-monochromatic light, This represents the absolute radiance responsivity function of the spectrometer. This refers to the center wavelength adjustment range of the monochromator. The center wavelength of the monochromator output ,bandwidth The spectral range corresponding to quasi-monochromatic light For spectrometer The spectral range corresponding to the channel's absolute spectral responsivity. .

[0052] Indicates the output center wavelength of the monochromator Bandwidth is The total radiance of quasi-monochromatic light This indicates that the center wavelength of the monochromator output is The normalized radiance function of quasi-monochromatic light, The monochromator outputs the normalized sum of quasi-monochromatic light at different center wavelengths. If the set of quasi-monochromatic light at any center wavelength output by the monochromator is considered equivalent to a broadband light source, then... This is equivalent to the sum of the normalized radiance of a broadband light source across all wavelengths. Formula (1) can be expressed as: (2) Therefore, calibrating a spectrometer using monochromatic light via wavelength scanning can be equivalent to directly calibrating the spectrometer using a broadband light source. Different monochromator bandwidths result in different equivalent broadband light sources. When the monochromator is set to different bandwidths, calibrating the spectrometer's radiance responsivity with the monochromator can be understood as calibrating the spectrometer's radiance responsivity with broadband light sources of the same type but different intensities.

[0053] Given that the radiance function of the monochromator output light is approximately a Gaussian function, use the normalized Gaussian function to represent the center wavelength of the monochromator output. Bandwidth is The quasi-monochromatic radiance function is given. The absolute spectral radiance responsivity function of most spectrometers is also close to a Gaussian function, and can similarly be represented by a Gaussian function. Considering the spectral line shape of the monochromator output light, the asymmetry and flat top of the absolute spectral radiance responsivity line shape of the spectrometer, and the inconsistent bandwidth of each center wavelength (or each channel of the spectrometer), theoretical calculations and analysis show that when the bandwidth of the quasi-monochromatic light output by the monochromator is less than the bandwidth of the spectrometer, the influence of the monochromator bandwidth variation on the spectrometer radiance calibration results is better than 0.1% and can be ignored.

[0054] Example 3 To further verify the effectiveness of the device and method of the present invention, this embodiment provides a practical application example based on the above-described device and method. The parameters and selection of each component are as follows: Supercontinuum laser: The NKT Photonics EXB-6 supercontinuum laser is selected, with a spectral coverage of 400nm-2400nm and a long-term stability of ≤0.3% / h.

[0055] Monochromator: The Omni-λ3009i monochromator is selected, which has three built-in blazed gratings (1200 / 600 / 600g / mm). Combined with the grating combination, it can achieve spectral coverage of 330nm-3000nm and can fully adapt to the calibration band requirements of 400nm-2400nm.

[0056] Monochromator entrance slit and monochromator exit slit: Both are electrically adjustable slits with an adjustment range of 0.01mm-3mm. They are driven by stepper motors and, with feedback from the laser wavelength meter, can achieve automated and precise adjustment of the monochromator bandwidth from 0.1nm to 10nm, with a bandwidth adjustment accuracy of ±0.01nm.

[0057] Integrating sphere: It is a self-designed decoherent integrating sphere with an inner diameter of 180mm, an inlet diameter of 10mm, and an outlet diameter of 80mm. The inner liner of the integrating sphere is coated with a polytetrafluoroethylene diffuse reflection coating, which has a reflectivity of ≥0.96 in the 400nm-2500nm wavelength band.

[0058] Monitoring detector: Model S2281 Si photodiode.

[0059] Transmission radiometer: Built-in Si and InGaAs detectors, measuring spectral range covering 380nm-2500nm.

[0060] Control and Data Processing Module: Based on the Siemens S7-1200 PLC and combined with the Agilent 34970A data acquisition unit, integrated control software was developed on the LabVIEW platform.

[0061] 1) Verification of long-term light source stability: Using a transmissive radiometer as the measuring instrument, after the supercontinuum laser was turned on and the light source stabilized, the transmissive radiometer measured the emitted light from the integrating sphere for 1 hour. Experimental results show that the repeatability of the transmissive radiometer measurement is better than 0.3% over a 1-hour measurement period. That is, the stability of the experimental setup is better than 0.3% / h. Experimental data are as follows: Figure 3 As shown.

[0062] 2) The effect of monochromator bandwidth on spectrometer radiometric calibration results: Theoretical calculation results: Taking an SVC spectrometer as an example. A tunable supercontinuum laser was used as the light source, and a standard luminance meter from the National Institute of Metrology was used as the luminance standard. The radiance responsivity function of the 833.5nm channel of the SVC spectrometer in the wavelength range of 700nm-960nm was measured. The output light function of the monochromator was expressed as a normalized Gaussian function. Using Equation 1, the radiance responsivity of the SVC spectrometer calibrated at different bandwidths of the monochromator was calculated. The calculation results are shown in Table 1. Using the radiance responsivity of the SVC spectrometer calibrated at a bandwidth of 1nm as the standard, the relative deviation between the radiance responsivity of the SVC spectrometer calibrated at different bandwidths was evaluated.

[0063] Table 1. Radiation Responsivity of SVC Spectrometer Calibrated at Different Bandwidths of Monochromator

[0064] Experimental Results: The SVC spectrometer was calibrated experimentally using a transmissometer as the luminance reference. The monochromator bandwidth was adjusted to 2nm, 4nm, and 6nm respectively. Using the calibration device provided in this embodiment, the radiance responsivity of the SVC spectrometer at the three monochromator bandwidths was measured. The results are as follows: Figure 4 As shown, the radiance responsivity of the SVC spectrometer calibrated with a monochromator at a bandwidth of 2 nm was used as a standard, and the differences between the radiance responsivity calibrated with the monochromator at bandwidths of 4 nm and 6 nm and the standard were compared. Experimental results show that the relative deviation between the radiance responsivity calibrated with the monochromator at bandwidths of 4 nm and 6 nm and the radiance responsivity calibrated with the monochromator at a bandwidth of 2 nm is better than 0.5%. The experimental measurement uncertainty is approximately 0.9%, which indicates that the radiance responsivity results of the SVC spectrometer calibrated with different bandwidths of the monochromator are consistent.

[0065] 3) The single-wavelength measurement uncertainty of the calibration device described in this embodiment: Table 2 shows the uncertainty assessment of the calibration device in this embodiment, and Table 3 shows the radiance comparison experiment between the calibration device in this embodiment and the standard radiance meter of the National Institute of Metrology. The results show that the measurement uncertainty of the calibration device in this embodiment is better than 0.5%. Using the standard radiance meter of the National Institute of Metrology as the radiance reference, the measurement deviation of the calibration device in this embodiment at the two wavelengths of 780nm and 851.9nm is approximately 0.3%, which fully demonstrates that the measurement uncertainty of the calibration device in this embodiment is better than 0.5%.

[0066] Table 2. Uncertainty assessment of single-wavelength radiance measurement of the calibration device in this embodiment.

[0067] Table 3. Radiation measurement results and relative deviations of the calibration device and the radiance meter from the National Institute of Metrology in this embodiment.

[0068] Therefore, this invention employs the aforementioned high-precision radiance calibration device and method with adaptive bandwidth. By introducing a theoretical model of "minimal bandwidth influence" as the core criterion, it eliminates ineffective bandwidth adjustments, improves the signal-to-noise ratio of the spectrometer under test, and thus enhances its measurement accuracy. Simultaneously, it coordinates the adjustment of the monochromator bandwidth and the rotation speed of the diffuse reflector to further suppress the influence of laser interference effects and improve calibration accuracy. By replacing traditional manual calibration with a fully automated bandwidth adjustment and measurement process, it improves measurement accuracy, reduces operational errors, and shortens the calibration cycle across the entire spectral band. Through the coordinated optimization of bandwidth, filter, and rotation speed of the diffuse reflector, it reduces the residual linear polarization of the integrating sphere output light, improves the level of spectral stray light suppression, and enhances the calibration accuracy of devices such as polarization remote sensors.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-precision radiance calibration device with adaptive bandwidth, characterized in that, It includes a light source module, an automatic bandwidth adjustment monochromator module, a uniform light and depolarization module connected in sequence, and a standard reference module corresponding to the optical path of the uniform light and depolarization module. It also includes a control and data processing module that is electrically connected to each of the above modules. The automatic bandwidth adjustment monochromator module includes a monochromator entrance slit, a filter, a monochromator, a monochromator exit slit, a semi-reflective mirror, and a laser wavelength meter. The monochromator entrance slit and the monochromator exit slit are driven by stepper motors. The control and data processing module has a built-in adaptive algorithm unit, which has a built-in bandwidth matching criterion. The laser wavelength meter measures the center wavelength and bandwidth of the monochromator output light in real time and transmits the data to the adaptive algorithm unit. The adaptive algorithm unit drives a stepper motor to adjust the width of the monochromator entrance slit and exit slit according to the bandwidth matching criterion, so as to achieve automatic and precise adjustment of the bandwidth from 0.1nm to 10nm, with an adjustment accuracy of ±0.01nm.

2. The high-precision radiance calibration device with adaptive bandwidth according to claim 1, characterized in that, The bandwidth matching criterion is specifically: when the bandwidth of the output light from the automatic bandwidth adjustment monochromator module... Less than the bandwidth of the spectrometer under test At this time, the influence of bandwidth change on the calibration results of the spectrometer under test is ignored; at this time, the bandwidth is dynamically adjusted by driving the stepper motor according to the real-time signal-to-noise ratio of the spectrometer under test, so that the signal-to-noise ratio of the spectrometer under test is stabilized above 1000.

3. The high-precision radiance calibration device with adaptive bandwidth according to claim 1, characterized in that, The light source module includes a supercontinuum laser, a first off-axis parabolic mirror, a second off-axis parabolic mirror, and a cylindrical mirror; the supercontinuum laser is used to provide continuous laser output; the first off-axis parabolic mirror, the second off-axis parabolic mirror, and the cylindrical mirror constitute a coupling optical path, and the input optical path of the coupling optical path is connected to the output optical path of the supercontinuum laser; the coupling optical path is used to convert the output light of the supercontinuum laser into a narrow beam and receive it by the monochromator entrance slit.

4. The high-precision radiance calibration device with adaptive bandwidth according to claim 3, characterized in that, The optical path within the automatic bandwidth adjustment monochromator module is as follows: the thin beam of light is received by the monochromator after passing through the entrance slit and filter; after passing through the exit slit, the semi-reflective mirror splits the output light of the monochromator into two beams; the reflected light from the semi-reflective mirror is received by the laser wavelength meter to measure the center wavelength and bandwidth of the output light of the monochromator; the transmitted light from the semi-reflective mirror is incident on the integrating sphere in the homogenizing and depolarizing module for radiance calibration; and a suitable filter is selected based on the wavelength fed back by the laser wavelength meter to eliminate higher-order diffraction spectra.

5. The high-precision radiance calibration device with adaptive bandwidth according to claim 4, characterized in that, The uniform light depolarization module includes an integrating sphere, a rotating diffuse reflector, and a monitoring detector; the rotating diffuse reflector is disposed inside the integrating sphere, and the monitoring detector is disposed on the side wall of the integrating sphere; the inner liner of the integrating sphere and the surface of the rotating diffuse reflector are both coated with a polytetrafluoroethylene diffuse reflective coating. The output light of the automatic bandwidth-adjustable monochromator module is beam-constricted by the first and second lenses and then incident on the rotating diffuse reflector plate through the light inlet of the integrating sphere. The motor drives the rotating diffuse reflector plate to rotate to suppress laser speckle. The monitoring detector monitors the change in the power of the light reflected from the integrating sphere and corrects the output power of the supercontinuum laser in real time.

6. The high-precision radiance calibration device with adaptive bandwidth according to claim 5, characterized in that, The standard reference module includes a transmissive radiometer and a data acquisition unit; the transmissive radiometer is mounted on an electrically controlled displacement platform, which is used to realize the optical path translation of the transmissive radiometer and align the transmissive radiometer with the output optical path of the light-equalizing and depolarizing module of the spectrometer under test. The data acquisition unit receives the electrical signal output by the transmissive radiometer, and the radiance responsivity of the transmissive radiometer is traced back to the standard luminance meter of the National Institute of Metrology. The radiance at the outlet of the integrating sphere of the transmissive radiometer is calculated based on the electrical signal output by the data acquisition unit and the radiance responsivity of the transmissive radiometer.

7. The high-precision radiance calibration device with adaptive bandwidth according to claim 6, characterized in that, The control and data processing module is used to coordinate the work of each module and process experimental data. The control and data processing module is connected to the monochromator, laser wavelength meter, monitoring detector, spectrometer under test, electrically controlled displacement platform, data acquisition device, supercontinuum laser and rotating diffuse reflector.

8. A high-precision radiance calibration method based on the adaptive bandwidth of the device according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Parameter Input: Input the key parameters of the spectrometer under test to the control and data processing module through the local interface of the touch screen and the remote interface of the Ethernet. The key parameters include center wavelength, channel bandwidth, detector type and field of view. S2. Preprocessing: Start all equipment in the calibration device, and establish electrical communication and optical path linkage between each device through the control and data processing module; install the spectrometer under test and the radiometer under test on the electrically controlled displacement platform, and drive the laser target to automatically position the two, so that the optical axes of the radiometer under test and the spectrometer under test are aligned with the center of the light output port of the integrating sphere of the uniform light and depolarization module; start the supercontinuum laser and preheat for 30 minutes. The output light of the supercontinuum laser is converted into a narrow beam through the coupling optical path and then incident on the entrance slit of the monochromator. The output light of the monochromator module with automatic bandwidth adjustment is incident on the rotating diffuse reflection plate inside the integrating sphere; The emission light from the integrating sphere is measured by a radiometer, and the measurement signal is transmitted to the control and data processing module. The control and data processing module determines the working status of the calibration device. The calibration device enters the working state after the optical power fluctuation of the supercontinuum laser is better than 0.3%. S3, Intelligent Bandwidth Matching: The control and data processing module calls the built-in adaptive algorithm unit to set the center wavelength and initial bandwidth of the monochromator output monochromator module. The light emitted from the monochromator module is reflected by a semi-reflective mirror and then incident on the laser wavelength meter. The laser wavelength meter measures the center wavelength and bandwidth of the emitted light in real time and feeds the signal back to the control and data processing module. Based on the channel bandwidth and real-time signal-to-noise ratio of the spectrometer under test, the control and data processing module drives the stepper motor to automatically adjust the monochromator entrance slit and exit slit to the optimal bandwidth while keeping the center wavelength constant. The laser wavelength meter provides continuous real-time feedback and is calibrated by the control and data processing module to ensure the center wavelength and bandwidth adjustment accuracy is ±0.01nm. S4. Light Source Output and Homogenization: The laser emitted from the supercontinuum laser enters the automatic bandwidth-adjustable monochromator module through a coupling optical path with a coupling efficiency of ≥95%. The automatic bandwidth-adjustable monochromator module outputs monochromatic light at the optimal bandwidth. The beam is then sequentially compressed by a semi-reflective mirror, a first lens, and a second lens. The diameter of the compressed beam is smaller than the diameter of the integrating sphere's entrance, ensuring that all monochromatic light is received by the integrating sphere. The beam is then incident on a rotating diffuser plate through the integrating sphere's entrance, achieving homogenization, depolarization, and interference effect suppression. The rotation speed of the rotating diffuser plate is linked to the output bandwidth of the automatic bandwidth-adjustable monochromator module. A monitoring detector monitors the changes in radiance on the inner wall of the integrating sphere in real time and feeds the signal back to the control and data processing module. The control and data processing module then fine-tunes the output power of the supercontinuum laser to ensure that the light source stability is ≤0.3% / h. S5. Alternating Calibration Measurement: The control and data processing module drives the electrically controlled displacement platform to insert the transmissive radiometer into the optical path of the integrating sphere's output port. The data acquisition unit records the transmissive radiometer's response signal and transmits it to the control and data processing module. The control and data processing module calculates the radiance of the light emitted from the integrating sphere according to the radiance transfer formula. Subsequently, the control and data processing module drives the electrically controlled displacement platform to translate, moving the transmissive radiometer away and aligning the spectrometer under test with the integrating sphere's output port. It collects the output code value of the spectrometer under test and calculates the radiance responsivity of each channel of the spectrometer under test according to the formula. The control and data processing module drives the stepper motor to repeatedly adjust the center wavelength of the automatic bandwidth adjustment monochromator module, performing wavelength scanning in the 400nm-2400nm spectral range. After point-by-point calculation and integration, the absolute radiance responsivity of each channel of the spectrometer under test is obtained. S6. Data Processing and Output: The control and data processing module performs normalized deviation analysis on the measurement data from S5 to verify the validity of the data; it integrates various error sources, including laser stability, radiometer measurement, and bandwidth adjustment, to automatically evaluate the calibration uncertainty and finally output a calibration report containing expanded uncertainty.

9. The high-precision radiance calibration method with adaptive bandwidth according to claim 8, characterized in that, In S5, the radiance transfer formula for the light emitted from the integrating sphere is: ； in, To transmit the output current value of the radiometer when measuring the light emitted from the integrating sphere. To transmit the radiance responsivity of the radiometer; The spectrometer under test i The radiance responsivity of the channel to quasi-monochromatic light with wavelength λ is: ； in The wavelength of the monochromator is Time, spectrometer under test i The channel's integral time normalized output code value; The spectrometer under test i The formula for calculating the absolute radiance responsivity of a channel is: ； in, and These are the lower and upper limits of the scanning wavelength for the automatic bandwidth-adjustable monochromator module, respectively. The wavelength adjustment interval for the quasi-monochromatic light output by the automatic bandwidth-adjustable monochromator module.

10. The high-precision radiance calibration method with adaptive bandwidth according to claim 8, characterized in that, In S3, the optimal bandwidth is the maximum bandwidth that satisfies the condition that "the output bandwidth of the automatic bandwidth adjustment monochromator module is less than the channel bandwidth of the spectrometer under test" and makes the signal-to-noise ratio of the spectrometer under test reach more than 1000. In S4, the linkage logic between the rotation speed of the rotating diffuse reflector and the output bandwidth of the automatic bandwidth adjustment monochromator module is as follows: the smaller the output bandwidth of the automatic bandwidth adjustment monochromator module, the higher the rotation speed of the rotating diffuse reflector, in order to reduce the influence of light source polarization and non-uniformity.

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