NESR Measurement Method and System for Infrared Spectral Radiometer Based on Calibration Residuals

Abstract

The present disclosure provides a method and system for measuring the NESR of an infrared spectral radiometer based on calibration residuals, relating to the field of infrared spectral technology, including obtaining the mean interference data of a low-temperature blackbody and obtaining the mean interference data of a high-temperature blackbody; respectively performing spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody; based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody, using a complex radiation calibration method to calculate the complex radiation calibration coefficient; using the complex radiation calibration coefficient to perform complex radiation calibration to obtain the calibrated spectral radiance, and taking the imaginary part residual value of the calibrated spectral radiance as the NESR value of the instrument. It can better eliminate the phase deviation introduced by different temperature target scenarios and the instrument's own radiation, etc., and improve the test accuracy of the Fourier transform infrared spectral radiometer.

Description

Technical Field

[0001] The present disclosure relates to the technical field of infrared spectroscopy, and particularly to a method and system for measuring the NESR of an infrared spectrometer based on calibration residuals. Background Art

[0002] The statements in this part only provide background technical information related to the present disclosure and do not necessarily constitute prior art.

[0003] NESR (Noise Equivalent Spectral Radiance) is an important indicator for measuring the detection sensitivity of a Fourier transform infrared spectrometer. According to the theoretical formula, NESR is related to factors such as the instantaneous field of view angle, optical efficiency, interferometer modulation depth, optical effective aperture, detector photosensitive area, integration time, sampling times, spectral resolution, and detector spectral responsivity of the Fourier transform infrared spectrometer. Considering that parameters such as the interferometer modulation depth and instantaneous field of view angle are difficult to measure in practice, this brings great inconvenience to the acceptance, comparison, testing, etc. of Fourier transform infrared spectrometers.

[0004] Fourier transform spectral measurement technology has the advantages of high spectral resolution, high optical throughput, multi-channel, wide spectral coverage, etc., and is a very important high-resolution spectral analysis technology. Especially for wide-band infrared spectral radiation measurement, it has been widely used in many fields such as space remote sensing, target characteristic research, atmospheric detection, material analysis, security and chemical defense, metrology, laboratories, environment, medical treatment, military analysis, criminal investigation, etc. With the rapid development of infrared stealth technology, hypersonic technology, etc., there is an urgent need for high-sensitivity real-time measurement of infrared spectral radiation parameters for low-radiation and fast-flashing targets.

[0005] Existing NESR evaluation methods mostly adopt a scheme based on real-number radiation calibration combined with multiple measurements of a standard blackbody target and calculating the standard deviation of multiple measurement results. At this time, the calculated value of NESR is directly related to the number of measurements of the standard blackbody target, and a large amount of data needs to be obtained to get an approximate value. The test is time-consuming and laborious and requires processing a large amount of data, and the influence of the data processing scheme on infrared spectral radiation measurement is not considered either. Therefore, the evaluated NESR has a large deviation. Summary of the Invention

[0006] In order to solve the above problems, the present disclosure proposes a method and system for measuring the NESR of an infrared spectrometer based on calibration residuals. By adopting phase alignment and complex radiation calibration, the phase deviation introduced by different temperature target scenarios and instrument self-radiation, etc. is eliminated, the test accuracy of the Fourier transform infrared spectrometer is improved, and a more realistic NESR parameter of the instrument is given.

[0007] According to some embodiments, the present disclosure adopts the following technical solutions:

[0008] NESR measurement method for infrared spectral radiometer based on calibration residual, comprising:

[0009] Set the temperature of the standard blackbody to a low temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the low-temperature blackbody; set the temperature of the standard blackbody to a high temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the high-temperature blackbody;

[0010] Perform spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody; based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody, use the complex radiation calibration method to calculate the complex radiation calibration coefficient;

[0011] Use the complex radiation calibration coefficient to perform complex radiation calibration, obtain the calibrated spectral radiance, and take the imaginary part residual value of the calibrated spectral radiance as the NESR value of the instrument.

[0012] According to some embodiments, the present disclosure adopts the following technical solutions:

[0013] NESR measurement system for infrared spectral radiometer based on calibration residual, comprising:

[0014] Parameter preprocessing module: used to set the temperature of the standard blackbody to a low temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the low-temperature blackbody; set the temperature of the standard blackbody to a high temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the high-temperature blackbody;

[0015] Inversion module, used to perform spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody;

[0016] NESR value measurement module, used to calculate the complex radiation calibration coefficient based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody by using the complex radiation calibration method; use the complex radiation calibration coefficient to perform complex radiation calibration, obtain the calibrated spectral radiance, and take the imaginary part residual value of the calibrated spectral radiance as the NESR value of the instrument.

[0017] According to some embodiments, the present disclosure adopts the following technical solutions:

[0018] A non-transitory computer-readable storage medium, which is used to store computer instructions, and when the computer instructions are executed by a processor, the NESR measurement method for the infrared spectral radiometer based on calibration residual as described above is implemented.

[0019] According to some embodiments, the present disclosure adopts the following technical solutions:

[0020] An electronic device includes: a processor, a memory, and a computer program; wherein, the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device runs, the processor executes the computer program stored in the memory so that the electronic device executes the method for measuring the NESR of an infrared spectrometer based on calibration residuals as described above.

[0021] Compared with the prior art, the beneficial effects of the present disclosure are as follows:

[0022] The present disclosure proposes a high-precision and simple measurement method for the NESR index of a Fourier transform infrared spectrometer, which does not require obtaining difficult-to-measure instrument parameters such as the modulation degree of the interferometer and the system optical efficiency, reduces the measurement difficulty, and solves the problem of complex instrument performance evaluation;

[0023] The method for evaluating and measuring the NESR parameter by using the complex radiation calibration residual proposed in the present disclosure, compared with the conventional standard deviation method, not only improves the measurement accuracy, but also greatly reduces the amount of data acquisition and data processing during the test process, and can more intuitively and accurately reflect the noise characteristics and detection sensitivity of the instrument;

[0024] The NESR evaluation and measurement method proposed in the present disclosure, by adopting a phase alignment and complex radiation calibration scheme, can better eliminate the phase deviation introduced by different temperature target scenarios and the self-radiation of the instrument, etc. It can not only improve the test accuracy of the Fourier transform infrared spectrometer, but also give more realistic NESR parameters of the instrument;

[0025] The present disclosure is applicable to the rapid performance evaluation and inspection of Fourier transform infrared spectrometers. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings forming a part of the present disclosure are used to provide a further understanding of the present disclosure. The schematic embodiments and descriptions thereof of the present disclosure are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure.

[0027] Figure 1 It is a flow chart of the NESR evaluation and measurement of an infrared spectrometer based on calibration residuals according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present disclosure will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs.

[0030] Note that the terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Example 1

[0032] In an embodiment of the present disclosure, a method for measuring the NESR of an infrared spectral radiometer based on calibration residuals is provided, including:

[0033] Step 1: Set the temperature of the standard blackbody to a low temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the low-temperature blackbody; set the temperature of the standard blackbody to a high temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the high-temperature blackbody.

[0034] Step 2: Perform spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody; based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody, use the complex radiation calibration method to calculate the complex radiation calibration coefficient.

[0035] Step 3: Use the complex radiation calibration coefficient to perform complex radiation calibration, obtain the calibrated spectral radiance, and take the imaginary part residual of the calibrated spectral radiance as the NESR value of the instrument.

[0036] As an example, the implementation process of the specific method for evaluating and measuring the NESR of an infrared spectral radiometer based on calibration residuals is as follows:

[0037] Step 1: Set the temperature of the standard blackbody to a low temperature T L , and wait for the blackbody temperature to stabilize;

[0038] Step 2: Collect the interference data of the low-temperature blackbody and perform superposition averaging to obtain the mean interference data IFG of the low-temperature blackbody L ;

[0039] Step 3: Set the temperature of the standard blackbody to a high temperature T H , and wait for the blackbody temperature to stabilize;

[0040] Step 4: Collect the interference data of the high-temperature blackbody and perform superposition averaging to obtain the mean interference data IFG of the high-temperature blackbody H ;

[0041] Step 5: Respectively for the obtained mean interference data IFG of the low-temperature blackbody L and the mean interference data IFG of the high-temperature blackbodyH , perform spectral inversion to obtain the corresponding complex spectrum Sp of the low-temperature blackbody L (λ) and the complex spectrum Sp of the high-temperature blackbody H (λ);

[0042] Step 6: Based on the complex spectrum Sp of the low-temperature blackbody L (λ) and the complex spectrum Sp of the high-temperature blackbody H (λ), adopt the complex radiation calibration method to calculate the complex radiation calibration coefficients R ca (λ) and R bis (λ);

[0043] Step 7: Set the standard blackbody temperature to the temperature T corresponding to the NESR test temperature of the instrument NESR , and wait for the blackbody temperature to stabilize;

[0044] Step 8: Collect the interference data of the blackbody, and perform superposition and averaging to obtain the average interference data IFG of the blackbody at the NESR test temperature NESR ;

[0045] Step 9: The average interference data IFG NESR is Fourier-transformed to obtain the restored complex spectrum Sp NESR (λ), and using the calibration coefficients R ca (λ) and R bis (λ), perform complex radiation calibration to obtain the calibrated spectral radiance Sp ca (λ);

[0046] Step 10: Take the imaginary part residue of the calibrated spectral radiance Sp ca (λ) as the NESR value of the instrument.

[0047] As an embodiment, in the said Step 2, Step 4 and Step 8, before performing the superposition and averaging of the interference data, first identify and eliminate the abnormal interference data, and perform processing such as the detection of the zero optical path difference point of the interference data; and use the zero optical path difference point as the reference point when performing the superposition and averaging.

[0048] Furthermore, in the said Step 5 and Step 9, before performing spectral inversion, preprocessing such as interference data spike detection and correction, nonlinear correction, interference data DC term elimination, interference data truncation or zero-padding, interference data translation transformation, and fringe counting error detection and correction are required to detect and eliminate the incorrect interference data.

[0049] As an embodiment, in steps 6 and 9, before calculating the complex radiation calibration coefficient and complex radiation calibration, it is necessary to align the phases of the complex spectra of the low-temperature blackbody and the complex spectra measured by NESR with the complex spectrum of the high-temperature blackbody as the reference to eliminate the phase deviations introduced by different temperature target scenes and the instrument's own radiation, etc.

[0050] The selection of the NESR test temperature of the instrument should fully consider the equivalent bright temperature corresponding to the peak of the detector spectral response, the instrument usage requirements, industry specifications, etc., and select an appropriate NESR test temperature.

[0051] When selecting the spectral band for NESR calculation, factors such as the peak region of the detector spectral response, the infrared transmittance of the ambient atmosphere, and the working spectral band of the instrument should be combined to select an appropriate spectral band.

[0052] As an embodiment, in step 6, the calculation steps of the complex radiation calibration coefficients R ca (ν) and R bis (ν) are as follows:

[0053] According to Planck's formula and the standard blackbody emissivity, calculate the standard values Lp L (λ) and Lp L (λ) of the infrared spectral radiance of the high-temperature blackbody and the low-temperature blackbody respectively:

[0054]

[0055]

[0056] In the formula, F inst is the instantaneous field of view angle of the Fourier transform infrared spectrometer, T L and T H are the temperatures of the low-temperature blackbody and the high-temperature blackbody respectively, with the unit of K, c1 = 3.7415×10 4 W·cm -2 ·μm 4 is the first radiation constant, c2 = 1.43879×10 4 μm·K is the second radiation constant, and λ is the spectral wavelength, with the unit of μm.

[0057] The complex radiation calibration coefficients R ca (λ) and R bis (λ) are given by the following formula:

[0058]

[0059]

[0060] The complex radiation calibration is calculated according to the following formula:

[0061]

[0062] In step 10, the instrument NESR is calculated according to the following formula:

[0063] NESR = Im(Sp ca (λ)) (6)

[0064] In the formula, Im() represents the operation of taking the imaginary part of a complex number.

[0065] Example 2

[0066] In an embodiment of the present disclosure, a NESR measurement system for an infrared spectral radiometer based on calibration residuals is provided, including:

[0067] Parameter preprocessing module: used to set the standard blackbody temperature to a low temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the low-temperature blackbody; set the standard blackbody temperature to a high temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the high-temperature blackbody;

[0068] Inversion module, used to perform spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody;

[0069] NESR value measurement module: used to calculate the complex radiation calibration coefficient based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody by using the complex radiation calibration method; use the complex radiation calibration coefficient to perform complex radiation calibration, obtain the calibrated spectral radiance, and take the imaginary part residual value of the calibrated spectral radiance as the NESR value of the instrument.

[0070] Example 3

[0071] In an embodiment of the present disclosure, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the steps of the NESR measurement method for an infrared spectral radiometer based on calibration residuals are implemented.

[0072] Example 4

[0073] In an embodiment of the present disclosure, an electronic device is provided, including: a processor, a memory, and a computer program; wherein, the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device runs, the processor executes the computer program stored in the memory so that the electronic device executes the steps of the NESR measurement method for an infrared spectral radiometer based on calibration residuals.

[0074] This disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing device generate means for implementing the specified functions in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0076] Although the specific embodiments of the disclosure have been described above in conjunction with the accompanying drawings, they are not intended to limit the scope of protection of the disclosure. Those skilled in the art should understand that, based on the technical solutions of the disclosure, various modifications or variations that can be made by those skilled in the art without creative efforts are still within the scope of protection of the disclosure.

Claims

1. A method for measuring the NESR of an infrared spectral radiometer based on calibration residuals, characterized in that, Including: Set the standard blackbody temperature to a low temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the low-temperature blackbody; Set the standard blackbody temperature to a high temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the high-temperature blackbody; Perform spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody; Based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody, use the complex radiometric calibration method to calculate the complex radiometric calibration coefficient; Use the complex radiometric calibration coefficient to perform complex radiometric calibration to obtain the calibrated spectral radiance. Take the imaginary part residue of the calibrated spectral radiance as the NESR value of the instrument. The measurement method of the NESR value of the instrument is: set the standard blackbody temperature to the temperature corresponding to the NESR test temperature of the instrument, and wait for the blackbody temperature to stabilize; collect the interference data of the blackbody and perform superposition averaging to obtain the mean interference data of the blackbody at the NESR test temperature; The mean interference data is subjected to spectral inversion to obtain a restored complex spectrum, and the complex radiometric calibration coefficient is used to perform complex radiometric calibration to obtain the calibrated spectral radiance; Take the imaginary part residue of the calibrated spectral radiance as the NESR value of the instrument.

2. The NESR measurement method of an infrared spectral radiometer based on calibration residuals according to claim 1, wherein The method of setting the standard blackbody temperature to a low temperature, waiting for the blackbody temperature to stabilize, and obtaining the mean interference data of the low-temperature blackbody is to collect the interference data of the low-temperature blackbody and perform superposition averaging to obtain the mean interference data of the low-temperature blackbody.

3. The method for measuring the NESR of an infrared spectral radiometer based on calibration residuals as described in claim 2, wherein, Before performing superposition averaging on the interference data, first identify and eliminate abnormal interference data, and perform zero optical path difference point detection and processing on the interference data; and use the zero optical path difference point as the reference point during superposition averaging.

4. The NESR measurement method of an infrared spectral radiometer based on calibration residuals as claimed in claim 1, wherein The method of setting the standard blackbody temperature to a high temperature, waiting for the blackbody temperature to stabilize, and obtaining the mean interference data of the high-temperature blackbody is to collect the interference data of the high-temperature blackbody and perform superposition averaging to obtain the mean interference data of the high-temperature blackbody.

5. The method for measuring the NESR of an infrared spectral radiometer based on calibration residuals as described in claim 1, wherein Before performing spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively, a preprocessing process of interference data spike detection and correction, nonlinear correction, interference data DC term elimination, interference data truncation or zero padding, interference data translation transformation, and fringe counting error detection and correction is performed.

6. The NESR measurement method of the infrared spectral radiometer based on the calibration residual as described in claim 1, wherein, Before calculating the complex radiometric calibration coefficient, the complex spectrum of the low-temperature blackbody and the complex spectrum of the NESR test should be phase-aligned based on the complex spectrum of the high-temperature blackbody to eliminate the phase deviation introduced by different temperature target scenarios and the instrument's own radiation.

7. An NESR measurement system for an infrared spectral radiometer based on calibration residuals, characterized in that Including: Parameter preprocessing module: used to set the standard blackbody temperature to a low temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the low-temperature blackbody; Set the standard blackbody temperature to a high temperature, wait for the blackbody temperature to stabilize, and obtain the mean interference data of the high-temperature blackbody; Inversion module, used to perform spectral inversion on the obtained mean interference data of the low-temperature blackbody and the mean interference data of the high-temperature blackbody respectively to obtain the corresponding complex spectra of the low-temperature blackbody and the high-temperature blackbody; The NESR value measurement module is used to calculate the complex radiation calibration coefficient based on the complex spectra of the low-temperature blackbody and the high-temperature blackbody by using the complex radiation calibration method; Using the complex radiation calibration coefficient, perform complex radiation calibration to obtain the calibrated spectral radiance. Take the imaginary part residual value of the calibrated spectral radiance as the NESR value of the instrument. The measurement method of the NESR value of the instrument is as follows: Set the standard blackbody temperature to the temperature corresponding to the NESR test temperature of the instrument and wait for the blackbody temperature to stabilize; Collect the interference data of the blackbody and perform superposition averaging to obtain the average interference data of the blackbody at the NESR test temperature; The average interference data is inversely spectrally transformed to obtain the restored complex spectrum, and the complex radiation calibration is performed using the complex radiation calibration coefficient to obtain the calibrated spectral radiance; Take the imaginary part residual value of the calibrated spectral radiance as the NESR value of the instrument.

8. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the method for measuring the NESR of an infrared spectroradiometer based on calibration residuals as described in any one of claims 1-6 is implemented.

9. An electronic device, characterized in that, Including: A processor, a memory, and a computer program; wherein, the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device runs, the processor executes the computer program stored in the memory so that the electronic device executes the method for measuring the NESR of an infrared spectroradiometer based on calibration residuals as described in any one of claims 1-6.

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