Medium-long wave infrared spectrum imaging data calibration device and method

Abstract

The invention discloses a medium-long wave infrared spectrum imaging data calibration device and method, and relates to the technical field of spectrum testing. The device provided by the invention comprises a black body, a cold screen, infrared spectrum imaging equipment and a data processing unit, the black body is arranged at an entrance pupil of the infrared spectrum imaging equipment; the cold screen is movably arranged in the infrared spectrum imaging equipment, and after the cold screen is moved, the cold screen is located at an entrance pupil of the infrared spectrum imaging equipment; and the infrared spectrum imaging equipment is electrically connected with the data processing unit. In the medium-long wave infrared spectral imaging data calibration process, the data processing unit adopts complex Fourier transform, frequency domain information can be converted into spatial domain information, the accuracy and reliability of data processing are improved, and accurate calibration of the infrared spectral imaging data is realized based on the acquired interference pattern and the data radiation calibration result. In addition, by arranging the cold screen, the influence of air interference in the spectral imaging equipment can be effectively reduced, and the precision of infrared spectral imaging data is improved.

Description

Technical Field

[0001] The invention relates to the technical field of spectrum testing, and in particular to a medium- and long-wave infrared spectrum imaging data calibration device and method. Background Art

[0002] Mid- and long-wave infrared spectral imaging technology is widely used in military, security, environmental monitoring and other fields. However, the existing mid- and long-wave infrared spectral imaging equipment is easily affected by the air interference inside the instrument during data radiation calibration, resulting in inaccurate imaging results.

[0003] To solve this problem, a medium- and long-wave infrared simultaneous spectral imaging system is proposed, which can obtain infrared images of multiple bands at the same time, and has important application value for target recognition and component analysis. However, due to the influence of the detector response curve and the atmospheric environment, the radiation information in the original image has errors, which need to be corrected by radiation calibration.

[0004] The existing calibration method generally adopts the general radiation calibration process of infrared spectrum imaging equipment, which measures the spectra of high and low temperature black bodies in turn, and obtains the instrument response and bias coefficient through formula (1):

[0005] S meas (v) = R(v)L meas (v)+O(v) (1)

[0006] In the formula, S meas (v) is the Fourier transformed spectrum, which represents the electrical signal output by the detector. meas (v) is the blackbody radiance; R(v) and O(v) are the response and bias coefficient of the radiation calibration, respectively.

[0007] Calibration is to obtain the system response and bias coefficient based on the standard source, and the subsequent measured electrical signal is converted into blackbody radiance through formula (2).

[0008] L meas (v)=(S meas (v)-O(v)) / R(v) (2)

[0009] Based on the above description, the limitations of existing calibration methods are:

[0010] 1) During the process of measuring high and low temperature black bodies in sequence, the internal state of the instrument changes, the bias coefficient O(v) obtained by calibration is not a fixed value, and the calibration deviation is large;

[0011] 2) When used on the ground, there is air inside the instrument. Characteristics such as CO2 and water vapor in the air appear in the response and bias of the calibration coefficients, interfering with the real spectrum. Even if nitrogen is filled to reduce the influence of air, after a long working time, the air interference characteristics will still appear in the calibration coefficients, interfering with the real spectrum. Summary of the invention

[0012] In order to solve the above problems existing in the prior art, the present invention provides a medium- and long-wave infrared spectral imaging data calibration device and method.

[0013] To achieve the above object, the present invention provides the following solutions:

[0014] A medium- and long-wave infrared spectrum imaging data calibration device, comprising: a black body, a cold screen, an infrared spectrum imaging device and a data processing unit;

[0015] The black body is placed at the entrance pupil of the infrared spectrum imaging device; the cold screen is movably arranged in the infrared spectrum imaging device, and when the cold screen is moved, the cold screen is located at the entrance pupil of the infrared spectrum imaging device; the infrared spectrum imaging device is electrically connected to the data processing unit;

[0016] The infrared spectrum imaging device is used to obtain a first blackbody interference pattern, a second blackbody interference pattern, a cold screen interference pattern and a target interference pattern;

[0017] The data processing unit is used to obtain a data radiation calibration result based on the first blackbody interference pattern, the second blackbody interference pattern and the cold screen interference pattern by using complex Fourier transform, and is used to complete the calibration processing of infrared spectrum imaging data based on the target interference pattern and the data radiation calibration result.

[0018] Optionally, the blackbody is an extended surface source blackbody.

[0019] Optionally, the cold shield is arranged in the infrared spectrum imaging device through mechanical movable parts.

[0020] Optionally, the first blackbody interference pattern is a blackbody interference pattern obtained at a first set temperature; and the second blackbody interference pattern is a blackbody interference pattern obtained at a second set temperature.

[0021] Optionally, the first set temperature is a temperature 10° C. higher than the ambient temperature; and the second set temperature is a temperature 10° C. lower than the ambient temperature.

[0022] The data processing unit comprises:

[0023] A radiation calibration module, electrically connected to the infrared spectrum imaging device, and configured to obtain a data radiation calibration result based on the first blackbody interference pattern, the second blackbody interference pattern, and the cold screen interference pattern;

[0024] The imaging processing module is electrically connected to the infrared spectrum imaging device and the radiation calibration module respectively, and is used to complete the calibration processing of the infrared spectrum imaging data based on the target interference pattern and the data radiation calibration result.

[0025] Furthermore, the present invention also provides a method for calibrating mid-wave and long-wave infrared spectral imaging data, which is applied to the above-mentioned mid-wave and long-wave infrared spectral imaging data calibration device; the method comprises:

[0026] Obtaining a first blackbody interference pattern, a second blackbody interference pattern, and a cold screen interference pattern;

[0027] Obtaining a first differential interference pattern based on the first blackbody interference pattern and the cold screen interference pattern;

[0028] Obtaining a second differential interference pattern based on the second blackbody interference pattern and the cold screen interference pattern;

[0029] Performing a complex Fourier transform on the first differential interference pattern to obtain a first complex spectrum;

[0030] Performing a complex Fourier transform on the second differential interference pattern to obtain a second complex spectrum;

[0031] Obtaining a response coefficient and a bias coefficient using the first complex spectrum and the second complex spectrum;

[0032] Data radiation calibration is completed based on the response coefficient and the bias coefficient, and calibration processing of infrared spectrum imaging data is completed.

[0033] Optionally, completing data radiation calibration based on the response coefficient and the bias coefficient to complete calibration processing of infrared spectrum imaging data specifically includes:

[0034] Obtain target interference pattern;

[0035] Performing a complex Fourier transform on the target interference pattern to obtain a complex spectrum;

[0036] The radiance of the target is determined based on the complex spectrum, the response coefficient, and the bias coefficient.

[0037] Optionally, the response coefficient is:

[0038] The bias coefficient is:

[0039] In the formula, is the response coefficient, is the first complex spectrum, is the second complex spectrum, L theory (v)bb,high is the blackbody radiance at the first set temperature, L theory (v) bb,low is the blackbody radiance at the second set temperature, is the response coefficient.

[0040] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0041] The present invention adopts complex Fourier transform in the process of calibrating medium and long wave infrared spectrum imaging data, which can convert frequency domain information into spatial domain information, and improve the accuracy and reliability of data processing. In addition, by setting a cold screen, the influence of air interference inside the spectrum imaging device can be effectively reduced, and the accuracy of infrared spectrum imaging data can be improved. By combining radiation calibration and imaging processing modules, accurate calibration of infrared spectrum imaging data is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A schematic diagram of the structure of the medium- and long-wave infrared spectral imaging data calibration device provided by the present invention; Figure 2 A flow chart of the method for calibrating mid- and long-wave infrared spectral imaging data provided by the present invention; Figure 3 This is a schematic diagram of the calibration process provided by the present invention.

[0045] Explanation of symbols:

[0046] 1- black body, 2- cold screen, 3- infrared spectrum imaging equipment, 4- data processing unit, 5- interference optical path, 6- focal plane detector. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] The object of the present invention is to provide a medium- and long-wave infrared spectrum imaging data calibration device and method, which can accurately calibrate the medium- and long-wave infrared spectrum imaging data to avoid interference with the real spectrum.

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] The medium- and long-wave infrared spectrum imaging data calibration device provided by the present invention comprises: a black body 1, a cold screen 2, an infrared spectrum imaging device 3 and a data processing unit 4.

[0051] The black body 1 is placed at the entrance pupil of the infrared spectrum imaging device 3. The cold screen 2 is movably arranged in the infrared spectrum imaging device 3, and when the cold screen 2 is moved, the cold screen 2 is located at the entrance pupil of the infrared spectrum imaging device 3. The infrared spectrum imaging device 3 is electrically connected to the data processing unit 4. The temperature of the cold screen can be determined according to actual needs, for example, it can be set to not less than -80°C.

[0052] The infrared spectrum imaging device 3 is used to obtain a first blackbody interference pattern, a second blackbody interference pattern, a cold screen interference pattern and a target interference pattern.

[0053] The data processing unit 4 is used to obtain a data radiation calibration result based on the first blackbody interferogram, the second blackbody interferogram and the cold screen interferogram by using complex Fourier transform, and to complete the calibration processing of infrared spectrum imaging data based on the target interferogram and the data radiation calibration result.

[0054] The data processing unit 4 performs a complex Fourier transform on the collected spectral imaging data, and can analyze external radiation and internal interference from the complex spectrum. Data radiation calibration is performed based on the complex Fourier transformed data and the radiation characteristics of known reference objects. The radiation calibrated data is further processed to generate accurate and reliable infrared spectral imaging results.

[0055] In practical applications, the black body 1 is preferably an extended surface source black body.

[0056] In addition, a cold screen 2 is provided inside the infrared spectrum imaging device 3 to reduce the influence of the internal radiation and internal air interference of the infrared spectrum imaging device 3, so as to accurately measure the internal radiation and internal air absorption of the infrared spectrum imaging device 3.

[0057] In actual application, the cold screen 2 is arranged in the infrared spectrum imaging device 3 through mechanical movable parts. The mechanical movable parts are structures such as lotus leaves, telescopic rods, and rotating shafts that can make the cold screen 2 located at the entrance pupil of the infrared spectrum imaging device 3.

[0058] Furthermore, in actual application, the first blackbody interference pattern used is a blackbody interference pattern obtained at a first set temperature (e.g., a temperature 10°C higher than the ambient temperature). The second blackbody interference pattern is a blackbody interference pattern obtained at a second set temperature (e.g., a temperature 10°C lower than the ambient temperature).

[0059] Further, in order to generate accurate and reliable infrared spectrum imaging results, the data processing unit 4 used in the present invention can be configured to include: a radiation calibration module and an imaging processing module. The radiation calibration module is electrically connected to the infrared spectrum imaging device 3, and is mainly used to obtain a data radiation calibration result based on the first black body interference pattern, the second black body interference pattern and the cold screen interference pattern. The imaging processing module is electrically connected to the infrared spectrum imaging device 3 and the radiation calibration module, respectively, and is mainly used to complete the calibration processing of the infrared spectrum imaging data based on the target interference pattern and the data radiation calibration result.

[0060] Among them, data radiation calibration is performed based on the data after complex Fourier transformation and the radiation characteristics of known reference objects. The radiation calibrated data is further processed to generate accurate and reliable infrared spectrum imaging results.

[0061] Furthermore, the present invention also provides a method for calibrating mid- and long-wave infrared spectral imaging data, which is applied to the above-mentioned mid- and long-wave infrared spectral imaging data calibration device. Figure 2 As shown, the method includes:

[0062] Step 100: Obtain a first blackbody interference pattern, a second blackbody interference pattern, and a cold screen interference pattern.

[0063] Step 101: Obtain a first differential interference pattern based on a first blackbody interference pattern and a cold screen interference pattern.

[0064] Step 102: Obtain a second differential interference pattern based on the second blackbody interference pattern and the cold screen interference pattern.

[0065] Step 103: Performing a complex Fourier transform on the first differential interference pattern to obtain a first complex spectrum.

[0066] Step 104: Perform a complex Fourier transform on the second differential interference pattern to obtain a second complex spectrum.

[0067] Step 105: Obtain a response coefficient and a bias coefficient using the first complex spectrum and the second complex spectrum. The response coefficient is determined by:

[0068]

[0069] The formula for determining the bias coefficient is:

[0070]

[0071] In the formula, is the response coefficient, is the first complex spectrum, is the second complex spectrum, L theory (v) bb,high is the blackbody radiance at the first set temperature, L theory (v) bb,low is the blackbody radiance at the second set temperature, is the response coefficient.

[0072] Step 106: Complete data radiation calibration based on the response coefficient and the bias coefficient, and complete the calibration processing of infrared spectrum imaging data. The specific implementation process of this step includes:

[0073] Step 1061: Obtain target interference pattern.

[0074] Step 1062: Perform a complex Fourier transform on the target interference pattern to obtain a complex spectrum.

[0075] Step 1063: Determine the radiance of the target based on the complex spectrum, the response coefficient and the bias coefficient.

[0076] The following is a specific application example to illustrate the specific implementation process of the above-mentioned solution of the present invention. In this embodiment, the infrared spectrum imaging device uses a spectrometer based on the following example: Figure 1 The structure shown in FIG. 1 is as follows: Figure 3 As shown, specifically including:

[0077] Step 1: The black body 1 is located at the entrance pupil of the spectrometer 3, and two temperatures, high and low, are set. The high temperature is 10°C higher than the ambient temperature, and the low temperature is 10°C lower than the ambient temperature.

[0078] Step 2: The cold screen 2 is located inside the spectrometer. When the cold screen 2 needs to be measured, the cold screen 2 is moved by mechanical components to be located at the entrance pupil of the field of view. When the measurement is not required, the cold screen 2 is moved away so that the cold screen 2 is located outside the entrance pupil of the field of view. The temperature of the built-in cold screen 2 is set to -80°C.

[0079] The interference optical path 5 of the spectrometer 3 splits the incoming light to obtain interference pattern data.

[0080] The light at the entrance pupil is split by the interference optical path 5 and enters the focal plane detector 6. Each pixel in the focal plane obtains interference pattern data to form an interference pattern data array.

[0081] The interference pattern data of each pixel is input to the data processing unit 4, and the data processing unit 4 performs complex FFT transformation on the interference pattern. By measuring the high-temperature, low-temperature blackbody and cold screen data, the response coefficient and the bias coefficient are calibrated.

[0082] Specifically, the specific implementation process of the above data processing is as follows:

[0083] 1) Measure the external high-temperature blackbody interference pattern (i.e., the first blackbody interference pattern) I bb,high Then switch the cold screen 2 into the field of view and measure the cold screen interferogram I coldplate After the measurement is completed, the cold screen 2 is removed. Measure the external low-temperature blackbody interference pattern (i.e., the second blackbody interference pattern) I bb,low Then switch the cold screen 2 into the field of view and measure the cold screen interferogram I coldplate , after the measurement is completed, remove the cold screen 2.

[0084] 2) The measured high and low temperature blackbody interference patterns are subtracted from the high and low temperature cold screen interference patterns to obtain two differential interference patterns (i.e., the first interference pattern and the second interference pattern):

[0085]

[0086] In the formula, ΔI bb,high is the first interference pattern, ΔI bb,low is the second interference pattern.

[0087] 3) According to formula (6), the two differential interference patterns are respectively subjected to complex FFT transformation to obtain complex spectra.

[0088]

[0089]

[0090] In the formula, v represents the wave number, is the complex spectrum after complex FFT transformation, ΔI is the differential interference pattern, ΔI bb,low is the second interference pattern, ΔI bb,high is the first interference pattern, is the complex spectrum after complex FFT transformation of the second differential interferogram, i.e., the second complex spectrum, is a complex spectrum obtained by performing complex FFT transformation on the first differential interference pattern, that is, a first complex spectrum.

[0091] 4) During the calibration process, the response coefficient and bias coefficient of the spectrometer are obtained based on the relationship between the spectral voltage value and the theoretical radiance of the black body [i.e., formula (8)] using the obtained complex spectrum. The determination formulas of the response coefficient and the bias coefficient are shown in formula (3) and formula (4).

[0092] S meas (v) = R(v)L theory (v)+O(v) (8)

[0093] In the formula, S meas (v) is the Fourier transformed spectrum. L is the blackbody radiance. R(v) and O(v) are the response coefficient and bias coefficient, respectively.

[0094] Through complex calibration, the influence of internal radiation of the instrument on calibration is eliminated.

[0095] 5) Spectrum of external target to be measured Perform measurements and calculations, specifically:

[0096] Pointing to an external target, measure the interference pattern I out , and using Fourier transform, we get the complex spectrum for:

[0097]

[0098] In the formula, and The complex spectrum The real and imaginary parts of , i is the imaginary unit.

[0099] Then based on the obtained complex spectrum And the response coefficient and bias coefficient after radiation calibration are obtained as follows:

[0100]

[0101] Where, L meas (v) out is the obtained radiance, is the response coefficient after radiation calibration, is the bias coefficient after radiation calibration.

[0102] Based on the above description, the present invention has the following advantages over the prior art:

[0103] 1. The present invention adopts complex Fourier transform technology, which can convert frequency domain information into spatial domain information, thereby improving the accuracy and reliability of data processing.

[0104] 2. The present invention introduces built-in cold screen technology to effectively reduce the influence of air interference inside the instrument and improve the accuracy of infrared spectral imaging data.

[0105] 3. The present invention combines a radiation calibration module and an imaging processing module to achieve accurate calibration of infrared spectrum imaging data.

[0106] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0107] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A medium and long wave infrared spectrum imaging data calibration device, characterized in that: include: Black bodies, cold screens, infrared spectral imaging equipment and data processing units; The black body is placed at the entrance pupil of the infrared spectrum imaging device; The cold screen is movably arranged in the infrared spectrum imaging device, and when the cold screen is moved, the cold screen is located at the entrance pupil of the infrared spectrum imaging device; the infrared spectrum imaging device is electrically connected to the data processing unit; The infrared spectrum imaging device is used to obtain a first blackbody interference pattern, a second blackbody interference pattern and a cold screen interference pattern; The data processing unit is used to obtain a data radiation calibration result based on the first blackbody interference pattern, the second blackbody interference pattern and the cold screen interference pattern using complex Fourier transform, and is used to complete calibration processing of infrared spectrum imaging data based on the target interference pattern and the data radiation calibration result.

2. The medium- and long-wave infrared spectral imaging data calibration device according to claim 1, characterized in that: The black body is an extended surface source black body.

3. The medium- and long-wave infrared spectral imaging data calibration device according to claim 1, characterized in that: The cold screen is arranged in the infrared spectrum imaging device through mechanical movable parts.

4. The mid- and long-wave infrared spectral imaging data calibration device according to claim 1, characterized in that: The first blackbody interference pattern is a blackbody interference pattern obtained at a first set temperature; the second blackbody interference pattern is a blackbody interference pattern obtained at a second set temperature.

5. The medium- and long-wave infrared spectral imaging data calibration device according to claim 4, characterized in that: The first set temperature is a temperature 10° C. higher than the ambient temperature; the second set temperature is a temperature 10° C. lower than the ambient temperature.

6. The medium- and long-wave infrared spectral imaging data calibration device according to claim 1, characterized in that: The data processing unit comprises: A radiation calibration module, electrically connected to the infrared spectrum imaging device, and configured to obtain a data radiation calibration result based on the first blackbody interference pattern, the second blackbody interference pattern, and the cold screen interference pattern; The imaging processing module is electrically connected to the infrared spectrum imaging device and the radiation calibration module respectively, and is used to complete the calibration processing of the infrared spectrum imaging data based on the target interference pattern and the data radiation calibration result.

7. A method for calibrating mid- and long-wave infrared spectral imaging data, characterized in that: The method is applied to the medium- and long-wave infrared spectral imaging data calibration device according to any one of claims 1 to 6; the method comprises: Obtaining a first blackbody interference pattern, a second blackbody interference pattern, and a cold screen interference pattern; Obtaining a first differential interference pattern based on the first blackbody interference pattern and the cold screen interference pattern; Obtaining a second differential interference pattern based on the second blackbody interference pattern and the cold screen interference pattern; Performing a complex Fourier transform on the first differential interference pattern to obtain a first complex spectrum; Performing a complex Fourier transform on the second differential interference pattern to obtain a second complex spectrum; Obtaining a response coefficient and a bias coefficient using the first complex spectrum and the second complex spectrum; Data radiation calibration is completed based on the response coefficient and the bias coefficient, and calibration processing of infrared spectrum imaging data is completed.

8. The method for calibrating mid- and long-wave infrared spectral imaging data according to claim 7, characterized in that: The data radiation calibration is completed based on the response coefficient and the bias coefficient, and the calibration processing of the infrared spectrum imaging data is completed, which specifically includes: Obtain target interference pattern; Performing a complex Fourier transform on the target interference pattern to obtain a complex spectrum; The radiance of the target is determined based on the complex spectrum, the response coefficient, and the bias coefficient.

9. The method for calibrating mid- and long-wave infrared spectral imaging data according to claim 7, characterized in that: The response factor is: The bias coefficient is: In the formula, is the response coefficient, is the first complex spectrum, is the second complex spectrum, L theory (v) bb,high is the blackbody radiance at the first set temperature, L theory (v) bb,low is the blackbody radiance at the second set temperature, is the response coefficient.

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