Infrared Thermal Imager Non-Uniformity Correction Method and Correction System

Abstract

The present invention provides a non-uniformity correction method and correction system for an infrared thermal imager, which relates to the technical field of infrared thermal imagers. The non-uniformity correction method for the infrared thermal imager includes the steps of: arranging a reference blackbody, a measured blackbody and an infrared thermal imager; obtaining a first temperature image after the measured blackbody is stabilized at a first temperature; obtaining a second temperature image after the reference blackbody is stabilized at a second temperature; obtaining a third temperature image after the measured blackbody is stabilized at a third temperature; obtaining a fourth temperature image of the reference blackbody again; calculating a compensation coefficient according to the first temperature image, the second temperature image, the third temperature image and the fourth temperature image, and correcting the infrared thermal imager through the compensation coefficient. By setting a reference blackbody, the present invention can effectively reduce the influence of temperature drift on the non-uniformity correction accuracy and ensure the accuracy of non-uniformity correction of the infrared thermal imager.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared thermal imagers, and more particularly, to a method and a correction system for non-uniformity correction of an infrared thermal imager. Background Art

[0002] An infrared thermal imager is a device that measures the intensity of infrared radiation and processes it to generate an image of an object. Due to its non-contact and real-time characteristics, it is widely used in medical, engineering, military and other fields. Affected by the non-uniformity of the semiconductor material of the infrared thermal imager device, mask errors, process conditions, etc., the responsivity of each pixel will be inconsistent, resulting in non-uniformity of the infrared image. Therefore, non-uniformity correction technology is required for all infrared thermal imagers.

[0003] The existing non-uniformity correction technology includes the two-point correction method. However, when using the two-point correction method, due to the influence of the external environment temperature and the internal temperature of the device on the detector of the infrared thermal imager, temperature drift will occur. This makes the temperature measurement values at different time points deviate when the infrared thermal imager measures the same constant-temperature blackbody radiation source, resulting in additional non-uniformity errors, reducing the correction accuracy, and affecting the accuracy of non-uniformity correction of the infrared thermal imager.

[0004] In view of the above problems, there is currently no effective technical solution. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and a correction system for non-uniformity correction of an infrared thermal imager, which can effectively reduce the influence of temperature drift on the non-uniformity correction accuracy and ensure the accuracy of non-uniformity correction of the infrared thermal imager.

[0006] In a first aspect, the present invention provides a method for non-uniformity correction of an infrared thermal imager, including the following steps:

[0007] S1. Arrange a reference blackbody, a measured blackbody and an infrared thermal imager;

[0008] S2. After setting the temperature of the measured blackbody to be stable at a first temperature, obtain multiple first temperature images of the measured blackbody through the infrared thermal imager;

[0009] S3. After setting the temperature of the reference blackbody to be stable at a second temperature, obtain multiple second temperature images of the reference blackbody through the infrared thermal imager;

[0010] S4. After setting the temperature of the measured blackbody to be stable at a third temperature, obtain multiple third temperature images of the measured blackbody through the infrared thermal imager; the third temperature is different from the first temperature;

[0011] After completing step S4, obtain multiple fourth temperature images of the reference blackbody through the infrared thermal imager again;

[0012] S6. Calculate a compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and correct the infrared thermal imager with the compensation coefficient.

[0013] The non-uniformity correction method for the infrared thermal imager of the present invention is based on the traditional two-point correction method, compensates for the influence of temperature drift on the non-uniformity correction accuracy, improves the non-uniformity correction effect, and ensures the accuracy of the non-uniformity correction of the infrared thermal imager.

[0014] Further, the specific steps in step S6 include:

[0015] S61. Calculate the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image. The compensation coefficient includes a temperature drift value, a correction gain factor coefficient, and a correction offset coefficient; the correction gain factor coefficient is calculated based on the temperature drift value; the correction offset coefficient is calculated based on the correction gain factor coefficient;

[0016] S62. Correct the infrared thermal imager according to the correction gain factor coefficient and the correction offset coefficient.

[0017] Further, the specific steps in step S61 include:

[0018] S611. Calculate the average temperature value of each pixel point on the first temperature image to obtain a corresponding first temperature matrix;

[0019] S612. Calculate the average temperature value of each pixel point on the second temperature image to obtain a corresponding second temperature matrix;

[0020] S613. Calculate the average temperature value of each pixel point on the third temperature image to obtain a corresponding third temperature matrix;

[0021] S614. Calculate the average temperature value of each pixel point on the fourth temperature image to obtain a corresponding fourth temperature matrix;

[0022] S615. Calculate the temperature drift value, the correction gain factor coefficient, and the correction offset coefficient based on the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix.

[0023] Further, the specific steps in step S615 include:

[0024] S6151. Calculate the temperature drift value according to the following formula:

[0025] ;

[0026] Wherein, is the temperature drift value, is the fourth temperature matrix, is the second temperature matrix;

[0027] S6152. Calculate the correction gain factor coefficient according to the following formula:

[0028] ;

[0029] Wherein, is the correction gain factor coefficient, is the third temperature, is the first temperature, is the third temperature matrix, is the first temperature matrix;

[0030] S6153. Calculate the correction offset coefficient according to the following formula:

[0031] ;

[0032] Wherein, is the correction offset coefficient.

[0033] Further, the specific steps in step S62 include:

[0034] S621. Calibrate the infrared thermal imager according to the following formula:

[0035] ; ]>

[0036] Wherein, is the fifth temperature matrix output after calibration of the infrared thermal imager, is the sixth temperature matrix input before calibration of the infrared thermal imager.

[0037] Further, the specific steps in step S2 include:

[0038] S21. Adjust the position of the measured black body so that the center of the measured black body fills the field of view of the infrared thermal imager;

[0039] S22. Obtain at least 10 first temperature images;

[0040] The specific steps in step S3 include:

[0041] S31. Adjust the position of the reference black body so that the center of the reference black body fills the field of view of the infrared thermal imager;

[0042] S32. Obtain at least 10 of the second temperature images;

[0043] The specific steps in step S4 include:

[0044] S41. Adjust the position of the blackbody under test so that the center of the blackbody under test fills the field of view of the infrared thermal imager;

[0045] S42. Obtain at least 10 of the third temperature images;

[0046] The specific steps in step S5 include:

[0047] S51. Adjust the position of the reference blackbody so that the center of the reference blackbody fills the field of view of the infrared thermal imager;

[0048] S52. Obtain at least 10 of the fourth temperature images.

[0049] Further, the specific steps in step S1 include:

[0050] S11. Place the infrared thermal imager on a fixed platform; a moving platform is provided on one side of the lens of the infrared thermal imager;

[0051] S12. Place the reference blackbody and the blackbody under test on the moving platform; the moving platform can drive the reference blackbody and the blackbody under test to move so that the reference blackbody or the blackbody under test is aligned with the infrared thermal imager.

[0052] In a second aspect, the present invention provides a calibration system, including a reference blackbody, a blackbody under test, an infrared thermal imager, and a processor;

[0053] The infrared thermal imager is used to perform the following steps:

[0054] A1. After the temperature of the blackbody under test stabilizes at a first temperature, obtain multiple first temperature images of the blackbody under test;

[0055] A2. After the temperature of the reference blackbody stabilizes at a second temperature, obtain multiple second temperature images of the reference blackbody;

[0056] A3. After the temperature of the blackbody under test stabilizes at a third temperature, obtain multiple third temperature images of the blackbody under test; the third temperature is different from the first temperature;

[0057] A4. After completing step A3, obtain multiple fourth temperature images of the reference blackbody again;

[0058] The processor is used to calculate a compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and correct the infrared thermal imager by means of the compensation coefficient.

[0059] The correction system provided by the present invention is based on two blackbodies, and corresponding temperature images are obtained by controlling their temperatures, so as to calculate a compensation coefficient, thereby eliminating the additional non-uniformity error introduced by temperature drift and ensuring the accuracy of non-uniformity correction of the infrared thermal imager.

[0060] Further, when calculating the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image and correcting the infrared thermal imager by means of the compensation coefficient, the processor performs:

[0061] S61. Calculate the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image. The compensation coefficient includes a temperature drift value, a correction gain factor coefficient, and a correction offset coefficient; the correction gain factor coefficient is calculated based on the temperature drift value; the correction offset coefficient is calculated based on the correction gain factor coefficient;

[0062] S62. Correct the infrared thermal imager according to the correction gain factor coefficient and the correction offset coefficient.

[0063] Further, when calculating the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, the processor performs:

[0064] S611. Calculate the average temperature value of each pixel point on the first temperature image to obtain a corresponding first temperature matrix;

[0065] S612. Calculate the average temperature value of each pixel point on the second temperature image to obtain a corresponding second temperature matrix;

[0066] S613. Calculate the average temperature value of each pixel point on the third temperature image to obtain a corresponding third temperature matrix;

[0067] S614. Calculate the average temperature value of each pixel point on the fourth temperature image to obtain a corresponding fourth temperature matrix;

[0068] S615. Calculate the temperature drift value, the correction gain factor coefficient, and the correction offset coefficient based on the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix.

[0069] As can be seen from the above, the non-uniformity correction method for an infrared thermal imager provided by the present invention improves on the existing two-point correction method and reduces the influence of temperature drift on the non-uniformity correction accuracy in a compensatory manner, so that when the infrared thermal imager measures the same constant-temperature blackbody radiation source, the deviation between the temperature measurement values at different time points is reduced, achieving the effect of improving the non-uniformity correction accuracy.

[0070] Other features and advantages of the present invention will be described in the subsequent description, and, in part, will be obvious from the description, or will be understood by implementing the embodiments of the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structures specifically pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 FIG. is a flowchart of a non-uniformity correction method for an infrared thermal imager provided by an embodiment of the present invention.

[0072] Figure 2 FIG. is a schematic diagram of a correction system provided by an embodiment of the present invention.

[0073] Figure 3 FIG. is a temperature image when the blackbody under test is at the first temperature in an embodiment of the present invention.

[0074] Figure 4 FIG. is a temperature image when the blackbody under test is at the third temperature in an embodiment of the present invention.

[0075] Figure 5 FIG. is a temperature drift value image in an embodiment of the present invention.

[0076] Figure 6 FIG. is a temperature image of the blackbody under test at 32°C collected after the infrared thermal imager is corrected using the traditional two-point correction method.

[0077] Figure 7 FIG. is a temperature image of the blackbody under test at 32°C collected after the infrared thermal imager is corrected using the non-uniformity correction method for an infrared thermal imager provided by an embodiment of the present invention.

[0078] Reference Numerals: 1, fixed platform; 2, moving platform; 3, infrared thermal imager; 4, reference blackbody; 5, blackbody under test. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0079] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0080] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0081] Due to the influence of uneven semiconductor materials, mask errors, process conditions, etc. on the infrared thermal imager, the responsivity of each pixel will be inconsistent, resulting in non-uniformity of the infrared image. Therefore, the infrared thermal imager generally needs to be corrected for non-uniformity before use. When the two-point correction method is adopted, the detector of the infrared thermal imager is affected by the external environmental temperature and the internal temperature of the device, and temperature drift will occur. The temperature drift here specifically refers to: when the infrared thermal imager measures the same position of the same constant-temperature blackbody at different time points, there is a deviation between the measured temperature values (in fact, the temperature of the blackbody is constant and the measured temperature values should not change).

[0082] Refer to the attached Figure 3 、attachment Figure 4 and attachment Figure 5 Attachment Figure 3 is the temperature image when the measured blackbody is at the first temperature, and attachment Figure 4 is the temperature image when the measured blackbody is at the third temperature, and attachment Figure 5 is the temperature drift value image. According to the two sets of temperature data in attachment Figure 3 and attachment Figure 4 the temperature drift value image of the infrared thermal imager at two temperature points can be obtained (i.e., attachment Figure 5 ), according to attachment Figure 5The temperature data shows that the maximum temperature drift is 0.65 °C and the minimum is -0.26 °C. Thus, the maximum drift amplitude is 0.91 °C (maximum drift amplitude = maximum temperature drift - minimum temperature drift), and the average value is 0.26 °C. This indicates that the temperature drift introduces an additional non-uniform error in the non-uniformity correction, reducing the accuracy of the non-uniformity correction. The deviation caused by this temperature drift will be introduced into the non-uniformity correction process of the infrared thermal imager, increasing the additional non-uniformity error and thus affecting the accuracy of the non-uniformity correction.

[0083] It should be noted that the cause of the above temperature drift lies in the fact that the detector of the infrared thermal imager is affected by the external environmental temperature and the internal temperature of the device, and does not generally refer to temperature drifts caused by all other reasons (such as temperature drift caused by lens distortion of the infrared thermal imager). This invention proposes an infrared thermal imager non-uniformity correction method specifically for the temperature drift with the above specific cause.

[0084] Please refer to Figure 1 , Figure 1 which is the flowchart of the infrared thermal imager non-uniformity correction method. The infrared thermal imager non-uniformity correction method includes the following steps:

[0085] S1. Arrange a reference blackbody, a measured blackbody, and an infrared thermal imager;

[0086] S2. After stabilizing the temperature of the measured blackbody at the first temperature, obtain multiple first-temperature images of the measured blackbody through the infrared thermal imager;

[0087] S3. After stabilizing the temperature of the reference blackbody at the second temperature, obtain multiple second-temperature images of the reference blackbody through the infrared thermal imager;

[0088] S4. After stabilizing the temperature of the measured blackbody at the third temperature, obtain multiple third-temperature images of the measured blackbody through the infrared thermal imager; the third temperature is different from the first temperature;

[0089] S5. After completing step S4, obtain multiple fourth-temperature images of the reference blackbody through the infrared thermal imager again;

[0090] S6. Calculate the compensation coefficient based on the first-temperature images, second-temperature images, third-temperature images, and fourth-temperature images, and correct the infrared thermal imager with the compensation coefficient.

[0091] This invention is an improvement in the non-uniformity correction process of the infrared thermal imager (performed before using the infrared thermal imager), focusing on compensating for the influence of temperature drift to ensure the accuracy of non-uniformity correction, rather than solving the problem of whether the temperature measurement result of the infrared thermal imager after correction is consistent with the actual temperature (performed when using the infrared thermal imager).

[0092] In this embodiment, the calculated compensation coefficient can offset the influence brought by temperature drift, so that the non-uniformity of the infrared thermal imager can be accurately corrected. When the corrected infrared thermal imager measures temperature actually, under the environment of the same conditions, for an object with a constant temperature, the error between the temperature values measured at different time points will be greatly reduced, that is, the temperature values tend to be constant and are consistent with the actual situation (in fact, the blackbody temperature is constant, and the measured temperature values should not change).

[0093] Refer to the attached Figure 6 and the attached Figure 7 attachment, the Figure 6 attachment is the temperature image of the measured blackbody at 32°C collected after the infrared thermal imager is corrected by using the traditional two-point correction method, and the Figure 7 attachment is the temperature image of the measured blackbody at 32°C collected after the infrared thermal imager is corrected by using the infrared thermal imager non-uniformity correction method provided by the embodiment of the present invention. From the Figure 6 temperature data of the Figure 7 attachment, the standard deviation of the temperature image non-uniformity of the full field of view can be obtained to be about 9.24, and from the

[0094] temperature data of the

[0095] attachment, the standard deviation of the temperature image non-uniformity of the full field of view can be obtained to be about 8.37. Obviously, after compensating for the influence brought by temperature drift by the method of the present invention, the uniformity obtained by correction is higher than that of the traditional two-point correction method, thus proving that the present invention can effectively improve the accuracy of non-uniformity correction.

[0096] It should be noted that correcting the infrared thermal imager by the compensation coefficient specifically refers to compensating and correcting the input image in the field of view of the infrared thermal imager, and outputting / displaying the non-uniformity corrected image from the infrared thermal imager.

[0097] S61. Calculate the compensation coefficient according to the first temperature image, the second temperature image, the third temperature image and the fourth temperature image. The compensation coefficient includes a temperature drift value, a correction gain factor coefficient and a correction offset coefficient; the correction gain factor coefficient is calculated according to the temperature drift value; the correction offset coefficient is calculated according to the correction gain factor coefficient;

[0098] S62. Correct the infrared thermal imager according to the correction gain factor coefficient and the correction offset coefficient.

[0099] In this embodiment, the temperature drift value is used to offset the influence caused by temperature drift. By combining the temperature drift value, the correction gain factor coefficient and the correction offset coefficient are calculated to correct the infrared thermal imager, thereby avoiding introducing additional non-uniformity errors during calibration and ensuring the accuracy of non-uniformity correction.

[0100] In some embodiments, the specific steps in step S61 include:

[0101] S611. Calculate the average temperature value of each pixel point on the first temperature image to obtain the corresponding first temperature matrix;

[0102] S612. Calculate the average temperature value of each pixel point on the second temperature image to obtain the corresponding second temperature matrix;

[0103] S613. Calculate the average temperature value of each pixel point on the third temperature image to obtain the corresponding third temperature matrix;

[0104] S614. Calculate the average temperature value of each pixel point on the fourth temperature image to obtain the corresponding fourth temperature matrix;

[0105] S615. Calculate the temperature drift value, the correction gain factor coefficient and the correction offset coefficient according to the first temperature matrix, the second temperature matrix, the third temperature matrix and the fourth temperature matrix.

[0106] In this embodiment, for example, 3 first temperature images are obtained: the first temperature image a, the first temperature image b, and the first temperature image c. For the (i, j) pixel point of the first temperature image, i and j are the two pixel coordinate values of this pixel point, and the temperature values of the (i, j) pixel points of the 3 first temperature images are Ta_ij, Tb_ij, and Tc_ij respectively. Then, the average temperature value of the (i, j) pixel point = (Ta_ij + Tb_ij + Tc_ij) / 3; the obtained first temperature matrix is composed of the average temperature values of the (i, j) pixel points of the first temperature image. The methods for obtaining the second temperature matrix, the third temperature matrix and the fourth temperature matrix are the same as those for obtaining the first temperature matrix, and will not be elaborated here.

[0107] It should be noted that the first temperature matrix, the second temperature matrix, the third temperature matrix and the fourth temperature matrix are two-dimensional matrices, and the matrix size is related to the resolution of the infrared thermal imager. For example, if the resolution of the infrared thermal imager is 640*512, then the above matrix size is 640*512.

[0108] In some embodiments, the specific steps in step S615 include:

[0109] S6151. Calculate the temperature drift value according to the following formula:

[0110] ;

[0111] Among them, is the temperature drift value, is the fourth temperature matrix, is the second temperature matrix;

[0112] S6152. Calculate the correction gain factor coefficient according to the following formula:

[0113] ;

[0114] Among them, is the correction gain factor coefficient, is the third temperature, is the first temperature, is the third temperature matrix, is the first temperature matrix;

[0115] S6153. Calculate the correction offset coefficient according to the following formula:

[0116] ;

[0117] Among them, is the correction offset coefficient.

[0118] The temperature drift value calculated based on the above algorithm can accurately offset the influence brought by the temperature drift, and the calculation of the correction gain factor coefficient and the correction offset coefficient combines the consideration of the temperature drift value, so that the additional non-uniformity error introduced by the temperature drift can be eliminated during non-uniformity correction, thereby improving the correction accuracy and ensuring the accuracy of the non-uniformity correction of the infrared thermal imager.

[0119] In some embodiments, the specific steps in step S62 include:

[0120] S621. Correct the infrared thermal imager according to the following formula:

[0121] ;

[0122] Among them, is the fifth temperature matrix output after the correction of the infrared thermal imager, is the sixth temperature matrix input before the correction of the infrared thermal imager.

[0123] In this embodiment, after obtaining the correction gain factor coefficient and the correction offset coefficient, the above algorithm is used to compensate and correct the image input in the field of view of the infrared thermal imager, and then an image after non-uniformity correction is obtained.

[0124] It should be noted that the image output by the infrared thermal imager is the temperature distribution map of the object. Therefore, it can be understood that obtaining the temperature matrix means obtaining the corresponding temperature image.

[0125] In some embodiments, the specific steps in step S2 include:

[0126] S21. Adjust the position of the blackbody to be measured so that the center of the blackbody to be measured fills the field of view of the infrared thermal imager;

[0127] S22. Obtain at least 10 first temperature images;

[0128] The specific steps in step S3 include:

[0129] S31. Adjust the position of the reference blackbody so that the center of the reference blackbody fills the field of view of the infrared thermal imager;

[0130] S32. Obtain at least 10 second temperature images;

[0131] The specific steps in step S4 include:

[0132] S41. Adjust the position of the blackbody to be measured so that the center of the blackbody to be measured fills the field of view of the infrared thermal imager;

[0133] S42. Obtain at least 10 third temperature images;

[0134] The specific steps in step S5 include:

[0135] S51. Adjust the position of the reference blackbody so that the center of the reference blackbody fills the field of view of the infrared thermal imager;

[0136] S52. Obtain at least 10 fourth temperature images.

[0137] In this embodiment, filling the field of view of the infrared thermal imager with the blackbody can avoid the interference of the image of the non-blackbody part on the acquisition of the temperature matrix, ensuring that all pixel points in the acquired temperature image belong to the blackbody itself. In addition, in order to ensure the stability and accuracy of the acquired data, it is required to obtain at least 10 temperature images in each step.

[0138] In some embodiments, referring to Appendix Figure 2 , the specific steps in step S1 include:

[0139] S11. Place the infrared thermal imager 3 on the fixed platform 1; a moving platform 2 is provided on one side of the lens of the infrared thermal imager 3;

[0140] S12. Place the reference blackbody 4 and the blackbody to be measured 5 on the moving platform 2; the moving platform 2 can drive the reference blackbody 4 and the blackbody to be measured 5 to move so that the reference blackbody 4 or the blackbody to be measured 5 is aligned with the infrared thermal imager 3.

[0141] In this embodiment, the infrared thermal imager 3 is stably arranged on the fixed platform 1, which can ensure that the field of view range of the infrared thermal imager 3 does not change. The reference blackbody 4 and the measured blackbody 5 enter and exit the field of view range of the infrared thermal imager 3 driven by the moving platform 2. By controlling the movement of the moving platform 2, the reference blackbody 4 or the measured blackbody 5 is aligned with the infrared thermal imager 3. Only by ensuring the proper distance between the fixed platform 1 and the moving platform 2 in advance, the center of the reference blackbody 4 or the measured blackbody 5 can fill the field of view of the infrared thermal imager 3. The operation is simple and the adjustment is convenient and fast.

[0142] Please refer to Figure 2 , Figure 2 which is a calibration system in some embodiments of the present invention, including: a reference blackbody 4, a measured blackbody 5, an infrared thermal imager 3, and a processor (not shown, which can be specifically arranged inside or outside the infrared thermal imager);

[0143] The infrared thermal imager is used to perform the following steps:

[0144] A1. After the temperature of the measured blackbody is stabilized at the first temperature, obtain multiple first temperature images of the measured blackbody;

[0145] A2. After the temperature of the reference blackbody is stabilized at the second temperature, obtain multiple second temperature images of the reference blackbody;

[0146] A3. After the temperature of the measured blackbody is stabilized at the third temperature, obtain multiple third temperature images of the measured blackbody; the third temperature is different from the first temperature;

[0147] A4. After completing step A3, obtain multiple fourth temperature images of the reference blackbody again;

[0148] The processor is used to calculate a compensation coefficient according to the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and correct the infrared thermal imager through the compensation coefficient.

[0149] In some embodiments, when the processor calculates the compensation coefficient according to the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and corrects the infrared thermal imager through the compensation coefficient, it performs:

[0150] S61. Calculate the compensation coefficient according to the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image. The compensation coefficient includes a temperature drift value, a calibration gain factor coefficient, and a calibration offset coefficient; the calibration gain factor coefficient is calculated according to the temperature drift value; the calibration offset coefficient is calculated according to the calibration gain factor coefficient;

[0151] S62. Correct the infrared thermal imager according to the calibration gain factor coefficient and the calibration offset coefficient.

[0152] In some embodiments, when calculating the compensation coefficient according to the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, the processor performs:

[0153] S611. Calculate the average temperature value of each pixel point on the first temperature image to obtain the corresponding first temperature matrix;

[0154] S612. Calculate the average temperature value of each pixel point on the second temperature image to obtain the corresponding second temperature matrix;

[0155] S613. Calculate the average temperature value of each pixel point on the third temperature image to obtain the corresponding third temperature matrix;

[0156] S614. Calculate the average temperature value of each pixel point on the fourth temperature image to obtain the corresponding fourth temperature matrix;

[0157] S615. Calculate the temperature drift value, the calibration gain factor coefficient, and the calibration offset coefficient according to the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix.

[0158] In some embodiments, when calculating the temperature drift value, the calibration gain factor coefficient, and the calibration offset coefficient according to the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix, the processor performs:

[0159] S6151. Calculate the temperature drift value according to the following formula:

[0160] ;

[0161] Where, is the temperature drift value, is the fourth temperature matrix, is the second temperature matrix;

[0162] S6152. Calculate the calibration gain factor coefficient according to the following formula:

[0163] ;

[0164] Where, is the calibration gain factor coefficient, is the third temperature, is the first temperature, is the third temperature matrix, is the first temperature matrix;

[0165] S6153. Calculate the calibration offset coefficient according to the following formula:

[0166] ;

[0167] Among them, is the calibration offset coefficient.

[0168] In some embodiments, when the processor calibrates the infrared thermal imager according to the temperature drift value, the calibration gain factor coefficient, and the calibration offset coefficient, it performs:

[0169] S621. Calibrate the infrared thermal imager according to the following formula:

[0170] ;

[0171] Among them, is the fifth temperature matrix output after the calibration of the infrared thermal imager, is the sixth temperature matrix input before the calibration of the infrared thermal imager.

[0172] In some embodiments, after the temperature of the measured black body stabilizes at the first temperature, when the infrared thermal imager 3 acquires multiple first temperature images of the measured black body, it performs:

[0173] A11. When the center of the measured black body fills the field of view of the infrared thermal imager, acquire at least 10 first temperature images;

[0174] After the temperature of the reference black body stabilizes at the second temperature, when the infrared thermal imager 3 acquires multiple second temperature images of the reference black body, it performs:

[0175] A21. When the center of the reference black body fills the field of view of the infrared thermal imager, acquire at least 10 second temperature images;

[0176] After the temperature of the measured black body stabilizes at the third temperature, when the infrared thermal imager 3 acquires multiple third temperature images of the measured black body, it performs:

[0177] A31. When the center of the measured black body fills the field of view of the infrared thermal imager, acquire at least 10 third temperature images;

[0178] After acquiring the third temperature images of the measured black body, when the infrared thermal imager 3 acquires multiple fourth temperature images of the reference black body again, it performs:

[0179] A41. When the center of the reference black body fills the field of view of the infrared thermal imager, acquire at least 10 fourth temperature images.

[0180] In some embodiments, refer to Appendix Figure 2, the calibration system further includes a fixed platform 1 and a moving platform 2; an infrared thermal imager 3 is placed on the fixed platform 1; the moving platform 2 is arranged on one side of the lens of the infrared thermal imager 3; a reference blackbody 4 and a measured blackbody 5 are placed on the moving platform 2; the moving platform 2 can drive the reference blackbody 4 and the measured blackbody 5 to move so that the reference blackbody 4 or the measured blackbody 5 is aligned with the infrared thermal imager 3.

[0181] In this document, relational terms such as first and second are used solely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0182] The above description is only for the embodiments of the present invention and is not intended to limit the protection scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An infrared thermal imager non-uniformity correction method, characterized in that It includes the following steps: S1. Arrange a reference blackbody, a measured blackbody, and an infrared thermal imager; S2. After stabilizing the temperature of the measured blackbody at a first temperature, obtain multiple first temperature images of the measured blackbody through the infrared thermal imager; S3. After stabilizing the temperature of the reference blackbody at a second temperature, obtain multiple second temperature images of the reference blackbody through the infrared thermal imager; S4. After stabilizing the temperature of the measured blackbody at a third temperature, obtain multiple third temperature images of the measured blackbody through the infrared thermal imager; the third temperature is different from the first temperature; S5. After completing step S4, obtain multiple fourth temperature images of the reference blackbody through the infrared thermal imager again; S6. Calculate a compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and correct the infrared thermal imager with the compensation coefficient; The specific steps in step S6 include: S61. Calculate the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image. The compensation coefficient includes a temperature drift value, a correction gain factor coefficient, and a correction offset coefficient; the correction gain factor coefficient is calculated based on the temperature drift value; the correction offset coefficient is calculated based on the correction gain factor coefficient; S62. Correct the infrared thermal imager according to the correction gain factor coefficient and the correction offset coefficient; The specific steps in step S61 include: S611. Calculate the average temperature value of each pixel point on the first temperature image to obtain a corresponding first temperature matrix; S612. Calculate the average temperature value of each pixel point on the second temperature image to obtain a corresponding second temperature matrix; S613. Calculate the average temperature value of each pixel point on the third temperature image to obtain a corresponding third temperature matrix; S614. Calculate the average temperature value of each pixel point on the fourth temperature image to obtain a corresponding fourth temperature matrix; S615. Calculate the temperature drift value, the correction gain factor coefficient, and the correction offset coefficient based on the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix; The specific steps in step S615 include: S6151. Calculate the temperature drift value according to the following formula: ； Wherein, is the temperature drift value, is the fourth temperature matrix, is the second temperature matrix; S6152. Calculate the correction gain factor coefficient according to the following formula: ； wherein, is the calibration gain factor coefficient, is the third temperature, is the first temperature, is the third temperature matrix, is the first temperature matrix; S6153. Calculate the correction offset coefficient according to the following formula: ； Among them, is the correction offset coefficient; The specific steps in step S62 include: S621. Correct the infrared thermal imager according to the following formula: ； Among them, is the fifth temperature matrix output after calibration of the infrared thermal imager, is the sixth temperature matrix input before calibration of the infrared thermal imager.

2. The non-uniformity correction method for an infrared thermal imager according to claim 1, wherein The specific steps in step S2 include: S21. Adjust the position of the measured blackbody so that the center of the measured blackbody fills the field of view of the infrared thermal imager; S22. Obtain at least 10 first temperature images; The specific steps in step S3 include: S31. Adjust the position of the reference blackbody so that the center of the reference blackbody fills the field of view of the infrared thermal imager; S32. Obtain at least 10 second temperature images; The specific steps in step S4 include: S41. Adjust the position of the blackbody under test so that the center of the blackbody under test fills the field of view of the infrared thermal imager; S42. Obtain at least 10 of the third temperature images; The specific steps in step S5 include: S51. Adjust the position of the reference blackbody so that the center of the reference blackbody fills the field of view of the infrared thermal imager; S52. Obtain at least 10 of the fourth temperature images.

3. The non-uniformity correction method for an infrared thermal imager according to claim 1, wherein The specific steps in step S1 include: S11. Place the infrared thermal imager on a fixed platform; a moving platform is provided on one side of the lens of the infrared thermal imager; S12. Place the reference blackbody and the blackbody under test on the moving platform; the moving platform can drive the reference blackbody and the blackbody under test to move so that the reference blackbody or the blackbody under test is aligned with the infrared thermal imager.

4. A calibration system, characterized in that, It includes a reference blackbody, a blackbody under test, an infrared thermal imager, and a processor; The infrared thermal imager is used to perform the following steps: A1. After the temperature of the blackbody under test stabilizes at a first temperature, obtain multiple first temperature images of the blackbody under test; A2. After the temperature of the reference blackbody stabilizes at a second temperature, obtain multiple second temperature images of the reference blackbody; A3. After the temperature of the blackbody under test stabilizes at a third temperature, obtain multiple third temperature images of the blackbody under test; the third temperature is different from the first temperature; A4. After completing step A3, obtain multiple fourth temperature images of the reference blackbody again; The processor is used to calculate a compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and correct the infrared thermal imager with the compensation coefficient; When the processor calculates the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, and corrects the infrared thermal imager, it performs: S61. Calculate the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image. The compensation coefficient includes a temperature drift value, a correction gain factor coefficient, and a correction offset coefficient; the correction gain factor coefficient is calculated based on the temperature drift value; the correction offset coefficient is calculated based on the correction gain factor coefficient; S62. Correct the infrared thermal imager based on the correction gain factor coefficient and the correction offset coefficient; When the processor calculates the compensation coefficient based on the first temperature image, the second temperature image, the third temperature image, and the fourth temperature image, it performs: S611. Calculate the average temperature value of each pixel point on the first temperature image to obtain a corresponding first temperature matrix; S612. Calculate the average temperature value of each pixel point on the second temperature image to obtain a corresponding second temperature matrix; S613. Calculate the average temperature value of each pixel point on the third temperature image to obtain a corresponding third temperature matrix; S614. Calculate the average temperature value of each pixel point on the fourth temperature image to obtain a corresponding fourth temperature matrix; Calculate the temperature drift value, the correction gain factor coefficient, and the correction offset coefficient according to the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix; When calculating the temperature drift value, the correction gain factor coefficient, and the correction offset coefficient according to the first temperature matrix, the second temperature matrix, the third temperature matrix, and the fourth temperature matrix, the processor performs: S6151. Calculate the temperature drift value according to the following formula: ； Among them, is the temperature drift value, is the fourth temperature matrix, is the second temperature matrix; S6152. Calculate the correction gain factor coefficient according to the following formula: ； Among them, is the calibration gain factor coefficient, is the third temperature, is the first temperature, is the third temperature matrix, is the first temperature matrix; S6153. Calculate the correction offset coefficient according to the following formula: ； Among them, is the correction offset coefficient; When correcting the infrared thermal imager according to the temperature drift value, the correction gain factor coefficient, and the correction offset coefficient, the processor performs: S621. Correct the infrared thermal imager according to the following formula: ； Among them, is the fifth temperature matrix output after the correction of the infrared thermal imager, is the sixth temperature matrix input before the correction of the infrared thermal imager.

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