Temperature compensation method for infrared thermal imaging lens and infrared thermal imaging camera

Abstract

This application discloses a temperature compensation method for an infrared thermal imaging lens. It involves fitting the relationship between the sharpness code values ​​of focusing motors at different temperatures and magnifications to obtain a temperature compensation model; acquiring a common focal point and using it as the focus compensation offset for the temperature compensation model to correct it, resulting in a corrected temperature compensation model; acquiring the current temperature and magnification; and determining the temperature-compensated sharpness code value based on the current temperature, current magnification, and the corrected temperature compensation model to control the focusing motor to the corresponding position. This application enables real-time optimal temperature compensation during continuous zooming, improving the sharpness and timeliness of lens imaging.

Description

Technical Field

[0001] This application relates to the field of thermal imaging technology, and in particular to a temperature compensation method for an infrared thermal imaging lens and an infrared thermal imaging camera. Background Technology

[0002] Continuous zoom infrared thermal imaging lenses have wide applications, enabling the observation and imaging of targets of varying distances and sizes. However, when the temperature of the application environment fluctuates significantly, the refractive index of the optical lenses changes, and this temperature variation also causes deformation of the lenses, leading to defocusing and blurry images. Furthermore, when the size and distance of the target change, the zoom lens needs to adjust its magnification to find a suitable field of view. Changes in magnification during continuous zoom, from near to far, result in blurred images. Additionally, tolerances during lens manufacturing and assembly contribute to individual differences, leading to inconsistencies in the focal point. Summary of the Invention

[0003] The purpose of this application is to provide a temperature compensation method for an infrared thermal imaging lens, which solves the problem of unclear images caused by lens temperature changes, depth of field changes, and lens tolerances. It can calculate the optimal temperature compensation amount in real time during continuous zooming, realize lens temperature compensation under continuous zooming, ensure real-time clear imaging, and quickly adjust the lens to achieve clear imaging.

[0004] In a first aspect, this application provides a temperature compensation method for an infrared thermal imaging lens, the method comprising:

[0005] The clear code values ​​of focusing motors under different temperatures and magnifications were calibrated to obtain the mapping relationship between the three. Curve fitting was performed on the different mapping relationships to obtain the temperature compensation model.

[0006] Obtain the focal point of the infrared thermal imaging lens, use the focal point as the focus compensation offset of the temperature compensation model, and correct the temperature compensation model to obtain the corrected temperature compensation model.

[0007] The current temperature and magnification of the infrared thermal imaging lens are obtained. Based on the current temperature, current magnification, and the corrected temperature compensation model, the clear code value of the focusing motor after temperature compensation is determined, and the focusing motor is controlled to drive to the position corresponding to the clear code value after temperature compensation.

[0008] Optionally, the clear code values ​​of focusing motors under different temperatures and magnifications are calibrated to obtain the mapping relationship between them and the three factors. A three-dimensional third-order function is then fitted to the multiple different mapping relationships to obtain a temperature compensation model, including:

[0009] The infrared thermal imaging lens was placed in a temperature-controlled chamber;

[0010] Adjust the temperature in the temperature chamber and the magnification of the infrared thermal imaging lens. For each set of temperature and magnification, obtain the modulation transfer function (MTF) curve of the target imaging. Based on the maximum value of the MTF curve at the cutoff frequency, determine the clear code value of the focusing motor corresponding to that set of temperature and magnification.

[0011] A three-dimensional third-order function is fitted to multiple different mapping relationships, and the coefficients of the three-dimensional third-order function are obtained by the least squares method, thus obtaining the temperature compensation model.

[0012] Optionally, the parfocal point of the infrared thermal imaging lens is obtained, and the parfocal point is used as the focus compensation offset of the temperature compensation model, including:

[0013] For the current calibration temperature of the infrared thermal imaging lens, the first clear code value of the focusing motor corresponding to the maximum magnification and the second clear code value of the focusing motor corresponding to the minimum magnification are obtained respectively, and the difference between the first clear code value and the second clear code value is used as the current parfocal error.

[0014] If the current focus error is 0, the current calibration temperature is used as the corrected focus temperature, and the first or second clarity code value is used as the clarity code value of the corrected focus.

[0015] If the current focal point error is not zero, use optical simulation software to perform curve fitting on each calibration temperature and corresponding focal point error based on the simulation software, and obtain the first focal point temperature correction formula.

[0016] Based on the current calibration temperature, the current cofocal point error, and the first cofocal point temperature correction formula, determine the corrected cofocal point temperature;

[0017] Based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, the correction formula for the first cofocal clear code value is determined.

[0018] Based on the first cofocal focal point sharpness code value correction formula and the current calibration temperature, determine the corrected cofocal focal point sharpness code value;

[0019] The corrected focus temperature and the corrected focus sharpness code value are used as the focus compensation offset for the temperature compensation model.

[0020] Optionally, curve fitting is performed on each calibration temperature and the cofocal point error to obtain the first cofocal point temperature correction formula, including:

[0021] The correction formula for the temperature of the first cofocal point is expressed as follows:

[0022] T0=a1*(△R-(b1*T1*T1+b2*T1+b3)) 2 +a2*(△R-(b1*T1*T1+b2*T1+b3+a3;

[0023] Where T0 represents the corrected focal point temperature, ΔR represents the difference between the first and second clear code values, a1, a2, a3, b1, b2, and b3 represent the coefficients of the first focal point temperature correction formula, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0024] Based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, the correction formula for the first cofocal clear code value is determined, including:

[0025] The formula for correcting the first cofocal sharpness code value is expressed as follows:

[0026] R0 = p 10 *(T0-T1)+p 20 *(T0 2 -T1 2 )+p 30 *(T0 3 -T1 3 )+p 11 *(T0-T1)*Z tele +p 21 *(T0 2 -T1 2 )Z tele +p 12 *(T0-T1)Z tele 2 +R tele

[0027] Where R0 represents the sharpness code value of the corrected cofocal point, T0 represents the corrected cofocal point temperature, and T1 represents the current calibration temperature of the infrared thermal imaging lens. tele Z represents the first clear code value. tele p represents the maximum magnification. 10 p 20 p 30 p 11 p 21 p 12 The coefficients characterizing the temperature compensation model.

[0028] Optionally, the parfocal point of the infrared thermal imaging lens is obtained, and the parfocal point is used as the focus compensation offset of the temperature compensation model, including:

[0029] Based on the calibrated clear code values ​​of the focusing motors at different temperatures and magnifications, the difference between the clear code value of the focusing motor corresponding to the highest temperature at the maximum magnification and the clear code value of the focusing motor corresponding to the lowest temperature is obtained. The ratio of this difference to the temperature difference between the highest and lowest temperatures is calculated to determine the high-value temperature compensation slope corresponding to the maximum magnification.

[0030] Obtain the difference between the clear code value of the focusing motor corresponding to the highest temperature at the minimum magnification and the clear code value of the focusing motor corresponding to the lowest temperature. Calculate the ratio of this difference to the temperature difference between the highest and lowest temperatures to determine the low-value temperature compensation slope corresponding to the minimum magnification.

[0031] Obtain the third clear code value of the focusing motor corresponding to the maximum magnification at the current calibration temperature and the fourth clear code value of the focusing motor corresponding to the minimum magnification. Use the difference between the third clear code value and the fourth clear code value as the current parfocal error.

[0032] Based on the current cofocal error, the high-value temperature compensation slope, and the low-value temperature compensation slope, a second cofocal temperature correction formula is constructed.

[0033] Based on the current calibration temperature and the correction formula for the second cofocal point temperature, determine the corrected cofocal point temperature;

[0034] Using the corrected cofocal temperature, the third clear code value, and the high-value temperature compensation slope, a correction formula for the second cofocal clear code value is constructed.

[0035] Based on the second cofocal focal point sharpness code value correction formula and the current calibration temperature, determine the corrected cofocal focal point sharpness code value;

[0036] The corrected focus temperature and the corrected focus sharpness code value are used as the focus compensation offset for the temperature compensation model.

[0037] Optionally, based on the current cofocal error, the high-value temperature compensation slope, and the low-value temperature compensation slope, a second cofocal temperature correction formula is constructed, including:

[0038] Based on the high-value temperature compensation slope, a first relationship is determined between the clear code value of the focusing motor corresponding to the maximum magnification and the calibration temperature, where the first relationship is expressed as:

[0039] R tele =A1*T1+A2;

[0040] Among them, R tele A1 represents the sharp code value of the focusing motor corresponding to the maximum magnification, A1 represents the high-value temperature compensation slope, T1 represents the current calibration temperature of the infrared thermal imaging lens, and A2 represents the coefficient of the first relational expression.

[0041] Based on the low-value temperature compensation slope, a second relationship is determined between the clear code value of the focusing motor corresponding to the minimum magnification and the calibration temperature, whereby the second relationship is expressed as:

[0042] R wide =B1*T1+B2;

[0043] Among them, R wide B1 represents the clear code value of the focusing motor corresponding to the minimum magnification, B1 represents the low-value temperature compensation slope, T1 represents the current calibration temperature of the infrared thermal imaging lens, and B2 represents the coefficient of the second relation.

[0044] Based on the current homofocal error, the first relation, and the second relation, a second homofocal temperature correction formula is constructed, which is expressed as:

[0045]

[0046] Where T0 represents the corrected parfocal temperature, ΔR represents the current parfocal error, B1 represents the low-value temperature compensation slope, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0047] Using the corrected cofocal temperature, the third sharpness code value, and the high-temperature compensation slope, a formula for correcting the second cofocal sharpness code value is constructed, including:

[0048] Using the corrected cofocal temperature, the third sharpness code value, and the high-temperature compensation slope, a correction formula for the second cofocal sharpness code value is constructed. The second cofocal sharpness code value correction formula is expressed as follows:

[0049] R0=A1*(T0-T1)+R tele ;

[0050] Where R0 represents the sharp code value of the corrected homofocal point, T0 represents the temperature of the corrected homofocal point, and R tele A1 represents the sharpness code value of the focusing motor corresponding to the maximum magnification, A1 represents the high-value temperature compensation slope, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0051] Optionally, the temperature compensation model is modified using the homofocal point as the focus compensation offset of the temperature compensation model to obtain a modified temperature compensation model, including:

[0052] The temperature compensation model is modified using the clear code value of the homofocal focal point, the linear difference between the current temperature and the homofocal focal point temperature, resulting in the modified temperature compensation model expressed as follows:

[0053] R(T,Z)=R0+p 10 *(T-P0)+p 20 *(T2 -T0 2 )+p 30 *(T 3 -T0 3 )+p 11 *(T-T0)*Z+p 21 *(T 2 -T0 2 Z+p 12 *(T-T0)Z 2 ;

[0054] Where T represents the temperature variable, R0 represents the corrected clear code value of the cofocal point, T0 represents the corrected cofocal point temperature, Z represents the magnification, and p 10 p 20 p 30 p 11 p 21 p 12 The coefficients characterizing the temperature compensation model.

[0055] Optionally, the method further includes:

[0056] For each candidate object distance, the total depth of field range corresponding to the candidate object distance is calculated based on the aperture value of the infrared thermal imaging lens, the maximum magnification of the focal length, the candidate object distance, and the diameter of the mass circle.

[0057] Based on the total depth range corresponding to each candidate object distance calculated, if the overlapping depth between two adjacent total depth ranges is greater than a preset threshold, the two first candidate object distances corresponding to the two adjacent total depth ranges are obtained.

[0058] For the at least two first candidate object distances obtained, sort the first candidate object distances according to the distance between them;

[0059] The first candidate object distance is used as the calibration object distance, and the corrected temperature compensation model corresponding to each calibration object distance is determined according to the order of the first candidate object distances.

[0060] The system acquires the current object distance, current temperature, and current magnification of the infrared thermal imaging lens. Based on the current object distance, it selects the appropriate corrected temperature compensation model. Based on the current temperature, current magnification, and the selected corrected temperature compensation model, it determines the temperature-compensated sharpness code value of the focusing motor and controls the focusing motor to drive to the position corresponding to the temperature-compensated sharpness code value.

[0061] Optionally, the method further includes:

[0062] Without a ranging module, the infrared thermal imaging lens acquires its corresponding corrected temperature compensation model at at least three different calibration distance points.

[0063] The object distance of the infrared thermal imaging lens is adjusted to each of the three calibration object distance points from farthest to closest. At each calibration object distance point, the corresponding corrected temperature compensation model is called to obtain the clarity code value corresponding to the current temperature. The focusing motor is driven to move to the clarity code value. If the clarity of the corresponding captured image is lower than the preset clarity threshold, the object distance of the infrared thermal imaging lens is moved to the next calibration object distance point until the clarity of the corresponding captured image is higher than the preset clarity threshold. The corresponding calibration object distance point is then set as the optimal object distance point, and the corresponding corrected temperature compensation model is obtained based on the optimal object distance point.

[0064] On the other hand, an infrared thermal imaging camera is provided, the camera comprising:

[0065] A temperature sensor is used to obtain the lens temperature;

[0066] A processor for executing computer-readable instructions to implement the temperature compensation method for an infrared thermal imaging lens as described above.

[0067] The beneficial effects of the technical solution provided in this application include at least the following:

[0068] This application obtains a temperature compensation model that characterizes the relationship between the sharpness code value of the focusing motor and temperature and magnification. The temperature compensation model is then modified using a common focal point to obtain a modified temperature compensation model. This modified model allows the focusing motor to be quickly moved to the corresponding position when the lens temperature or magnification changes, eliminating the need to calculate defocus compensation for temperature compensation. This significantly simplifies the calculation process, reduces calculation errors, and enables real-time optimal temperature compensation during continuous zooming. It ensures real-time sharp imaging and allows for rapid adjustment of the lens for sharp imaging, improving the clarity and timeliness of infrared thermal imaging lenses. Modifying the temperature compensation model using a common focal point as the focus compensation offset eliminates the influence of individual differences between lenses on temperature compensation, thereby improving the accuracy of lens temperature compensation. Attached Figure Description

[0069] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 This is a first flowchart of the temperature compensation method for an infrared thermal imaging lens provided in the embodiments of this application;

[0071] Figure 2This is a second flowchart of the temperature compensation method for an infrared thermal imaging lens provided in the embodiments of this application;

[0072] Figure 3 This is a schematic diagram illustrating the relationship between the clear code value of the focusing motor and temperature and magnification provided in the embodiments of this application;

[0073] Figure 4 This is a schematic diagram illustrating the relationship between the clear code value and magnification of the focusing motor provided in the embodiments of this application;

[0074] Figure 5 This is a schematic diagram illustrating the relationship between the clear code value of the focusing motor and temperature, provided in an embodiment of this application.

[0075] Figure 6 This is the third flowchart of the temperature compensation method for an infrared thermal imaging lens provided in the embodiments of this application;

[0076] Figure 7 This is the fourth flowchart of the temperature compensation method for an infrared thermal imaging lens provided in the embodiments of this application;

[0077] Figure 8 This is a schematic diagram of the structure of the infrared thermal imaging camera provided in the embodiments of this application;

[0078] Figure 9 This is a schematic diagram of the structure of the computer device provided in the embodiments of this application. Detailed Implementation

[0079] The present application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application. Any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0080] Please refer to Figure 1 This application provides a temperature compensation method for an infrared thermal imaging lens, which includes steps S101-S103.

[0081] S101 calibrates the clear code values ​​of focusing motors under different temperatures and magnifications to obtain the mapping relationship between the three. Curve fitting is performed on the different mapping relationships to obtain the temperature compensation model.

[0082] For example, an infrared thermal imaging lens includes a focusing motor and a zoom motor. The focusing motor drives the focusing lens to move, achieving the focusing function. The focusing function refers to adjusting the sharpness of the target object in the image by changing the focal plane of the infrared thermal imaging lens, making the target object in the image as sharp as possible. The zoom motor drives the zoom lens to move, adjusting the zoom ratio of the infrared thermal imaging lens to determine the appropriate field of view of the image. When the magnification of the zoom lens changes, the focal plane corresponding to sharp focus may also change. The focusing motor of the lens needs to adjust in real time to maintain sharp imaging throughout the zoom process, i.e., sharp image throughout zoom.

[0083] The infrared thermal imaging lens is calibrated, and the sharpness code values ​​of the focusing motor under different temperatures and magnifications are calibrated. The mapping relationship between the sharpness code values ​​of the focusing motor under different temperatures and magnifications is obtained. The three-dimensional third-order function is fitted to the multiple different mapping relationships to obtain the temperature compensation model. The temperature compensation model characterizes the relationship between the sharpness code value of the focusing motor and temperature and magnification.

[0084] S102: Obtain the focal point of the infrared thermal imaging lens, use the focal point as the focus compensation offset of the temperature compensation model, correct the temperature compensation model, and obtain the corrected temperature compensation model.

[0085] In zoom optics design, when the magnification of a zoom lens changes from its minimum to its maximum, the focal plane of the infrared thermal imaging lens remains essentially within the range of sharp image quality. This is the theoretically designed parfocal point. Parfocal point can be understood as the ability of the target object to remain at the same focal point position when the lens zooms at different focal lengths (different magnifications), without requiring refocusing of the focal plane, ensuring a consistently sharp image. However, once the temperature changes, the parfocal point is disrupted; the lens will not have a parfocal point at other temperatures. In optical design, zoom lenses generally use 20°C as the theoretical parfocal point temperature. However, due to tolerances in lens thickness, eccentricity, surface shape, and air gaps during manufacturing and assembly, the parfocal point temperature can change.

[0086] In this embodiment, the temperature compensation model is modified by using the focus compensation offset of the parfocal point as the focus compensation offset of the temperature compensation model, thereby obtaining the modified temperature compensation model, which can eliminate the influence of individual differences of different lenses on temperature compensation.

[0087] S103: Obtain the current temperature and current magnification of the infrared thermal imaging lens; based on the current temperature, current magnification, and the corrected temperature compensation model, determine the clear code value of the focusing motor after temperature compensation; and control the focusing motor to drive to the position corresponding to the clear code value after temperature compensation.

[0088] For example, the temperature of the infrared thermal imaging lens is acquired by a temperature sensor installed in the lens. The current focal length of the infrared thermal imaging lens is obtained, and the current magnification is calculated as the ratio of the current focal length to the minimum focal length.

[0089] For example, the code value is used to characterize the position of the focusing motor, which can be obtained, for example, through an encoder. The sharpness code value of the focusing motor can be understood as the motor code value of the focusing motor when the lens generates a sharp image (e.g., when MTF is optimal or other sharpness indicators are optimal).

[0090] In this embodiment, a temperature compensation model is obtained to characterize the relationship between the sharpness code value of the focusing motor and temperature and magnification. The temperature compensation model is then corrected using a common focal point to obtain a corrected temperature compensation model. This allows the focusing motor to be controlled to move rapidly to the corresponding position when the lens temperature or magnification changes, eliminating the need to calculate defocus compensation for temperature compensation. This greatly simplifies the calculation steps, reduces calculation errors, and enables real-time calculation of the optimal compensation amount during continuous zooming. This achieves lens temperature compensation under continuous zooming, ensuring that the image remains sharp. Correcting the temperature compensation model using a common focal point as the focus compensation offset eliminates the influence of individual differences between different lenses on temperature compensation, thereby improving the accuracy of lens temperature compensation.

[0091] One embodiment of this application, such as Figure 2 As shown, the depth range is determined based on the parameter information of the infrared thermal imaging lens, and at least one calibration object distance is determined based on the depth range, including steps S201-S205.

[0092] S201, For each candidate object distance, calculate the total depth of field range corresponding to the candidate object distance based on the aperture value of the infrared thermal imaging lens, the maximum magnification of the focal length, the candidate object distance, and the diameter of the mass circle.

[0093] S202, based on the total depth range corresponding to each candidate object distance calculated, if the overlapping depth between two adjacent total depth ranges is greater than a preset threshold, obtain the two first candidate object distances corresponding to the two adjacent total depth ranges.

[0094] S203, for the at least two first candidate object distances obtained, sort each first candidate object distance according to the distance between each first candidate object distance;

[0095] S204, take the first candidate object distance as the calibration object distance, and determine the corrected temperature compensation model corresponding to each calibration object distance according to the order of the first candidate object distances;

[0096] S205: Obtain the current object distance, current temperature, and current magnification of the infrared thermal imaging lens; select the corresponding corrected temperature compensation model based on the current object distance; determine the temperature-compensated sharpness code value of the focusing motor based on the current temperature, current magnification, and the selected corrected temperature compensation model; and control the focusing motor to drive to the position corresponding to the temperature-compensated sharpness code value.

[0097] Because infrared lenses have large detector pixel sizes and long transmission wavelengths, they have a relatively large depth of field. Due to the varying depth of field, continuous zoom lenses cannot guarantee real-time image clarity during zooming from near to far. In this example, during calibration, multiple calibration object distances can be selected based on the depth of field range of the infrared thermal imaging lens. For each calibration object distance, a corresponding temperature compensation model is determined to cover temperature compensation across the entire object distance range, enabling real-time temperature compensation during zooming from near to far.

[0098] The change in the object distance range of an infrared thermal imaging lens is obtained through a rangefinder. The current object distance can be obtained through a rangefinder, such as laser rangefinder, radar rangefinder, AR rangefinder, etc.

[0099] For example, the formula for calculating the depth of field range is:

[0100]

[0101] Where σ represents the diameter of the mass circle, f represents the focal length, F represents the aperture value, L represents the distance to the candidate object, △L1 represents the foreground depth of field at the maximum focal length, △L2 represents the background depth of field at the maximum focal length, and △L represents the total depth of field at the maximum focal length.

[0102] The depth of field formula can be used to calculate the depth of field of a zoom lens at the telephoto end under different focusing distances. Calculations reveal overlaps in depth of field at different focusing distances. This means that more calibration distance curves are not necessarily better, and a single calibration distance curve cannot cover both near and far scenes. Therefore, an appropriate calibration distance can be selected based on the obtained depth of field range. According to the formula, the longer the focal length, the shorter the depth of field. Therefore, it is only necessary to find cases where the depth of field overlaps at the zoom lens's maximum magnification, and determine the calibration distance based on this overlap.

[0103] Therefore, for each candidate object distance, the total depth of field range corresponding to that candidate object distance is calculated based on the formula for calculating the depth of field range, the aperture value of the infrared thermal imaging lens, the maximum focal length, the candidate object distance, and the diameter of the mass circle. Based on the calculated total depth of field ranges, if the overlapping depth of field between two adjacent total depth of field ranges is greater than a preset threshold, two first candidate object distances corresponding to the two adjacent total depth of field ranges are obtained. The threshold can be set according to the actual situation. For example, the threshold can be set to 50 meters, 100 meters, etc. From the obtained first candidate object distances, they are sorted according to their distance, and the first candidate object distances are used as calibration object distances. For each determined calibration object distance, calibration is performed, and the corrected temperature compensation model corresponding to each calibration object distance is obtained according to the implementation method of the modified temperature compensation model described above. Obtain the current object distance of the lens, determine the depth of field range of the calibrated object distance based on the current object distance, select the corresponding calibrated object distance corrected temperature compensation model, determine the temperature-compensated sharpness code value of the focusing motor based on the corrected temperature compensation model, and control the focusing motor to drive to the position corresponding to the temperature-compensated sharpness code value.

[0104] Different calibration object distances will lead to different coefficients of the temperature compensation model and different corrected focal points. Therefore, in this embodiment, by determining different calibration object distances, the calibration process is performed separately to obtain the corrected temperature compensation model corresponding to each calibration object distance, so as to cover the temperature compensation within the entire object distance range. This allows the lens to perform real-time temperature compensation during zooming from near to far, ensuring that the infrared thermal imaging lens maintains the lens's sharpness throughout the continuous zooming process from near to far.

[0105] For example, a near-distance calibration object distance, a medium-distance calibration object distance, and a far-distance calibration object distance can be determined. Calibration is performed on the near-distance calibration object distance, the medium-distance calibration object distance, and the far-distance calibration object distance, respectively. Based on the above implementation method, the corresponding corrected temperature compensation model is obtained. During the real-time temperature compensation process of the lens, the corresponding corrected temperature compensation model is selected based on the current object distance. That is, one temperature compensation model is selected from the corrected temperature compensation models corresponding to the near-distance calibration object distance, the medium-distance calibration object distance, and the far-distance calibration object distance. Based on the selected corrected temperature compensation model, the temperature-compensated sharpness code value of the focusing motor is determined, and the focusing motor is controlled to drive to the position corresponding to the temperature-compensated sharpness code value.

[0106] For example, assuming the focal length f of an infrared thermal imaging lens used for outdoor long-distance monitoring is 30-300mm, paired with a detector pixel size of 12µm and a circle of confusion diameter σ of 0.048mm, the depth of field range is calculated for each candidate object distance using the formula described above. Based on the calculation results, three object distances are selected as calibration object distances: 300m (close-range calibration object distance), 500m (medium-range calibration object distance), and 2000m (long-range calibration object distance). The corresponding total depth of field ranges at the maximum focal length are 242m to 395m, 357m to 833m, and 769m to infinity, respectively. It can be seen that the coverage of each total depth of field range has an overlapping portion. The infrared thermal imaging lens has a monitoring distance of more than 300 meters. Therefore, based on the three calibration distances set above, three corresponding temperature compensation models are determined. During the continuous zooming process from near to far, the infrared thermal imaging lens determines the clear code value after compensation through different temperature compensation models, thereby realizing the function of keeping the lens clear throughout the continuous zooming process from near to far.

[0107] In one embodiment of this application, the method further includes:

[0108] Without a ranging module, the infrared thermal imaging lens acquires its corresponding corrected temperature compensation model at at least three different calibration distance points.

[0109] The object distance of the infrared thermal imaging lens is adjusted to each of the three calibration object distance points from far to near. At each calibration object distance point, the corresponding corrected temperature compensation model is called to obtain the clarity code value corresponding to the current temperature. The focusing motor is driven to move to the clarity code value. If the clarity of the corresponding captured image is lower than the preset clarity threshold, the object distance of the infrared thermal imaging lens is moved to the next calibration object distance point until the clarity of the corresponding captured image is higher than the preset clarity threshold. The corresponding calibration object distance point is set as the optimal object distance point, and the corresponding corrected temperature compensation model is obtained based on the optimal object distance point.

[0110] For example, the infrared thermal imaging lens includes a processor that stores multiple corrected temperature compensation models corresponding to calibrated object distances.

[0111] In this embodiment, if the infrared thermal imaging lens lacks a ranging module and its current object distance cannot be determined, a modified temperature compensation model corresponding to different pre-acquired calibration object distance points is used to search for each calibration object distance point from far to near. The optimal object distance point is determined by judging the sharpness of the captured image, thereby obtaining the corresponding modified temperature compensation model. Based on the determined modified temperature compensation model, temperature compensation of the lens under continuous zoom is achieved when the temperature and magnification of the infrared thermal imaging lens change.

[0112] One embodiment of this application calibrates multiple sets of clear code values ​​of focusing motors under different temperatures and magnifications to obtain mapping relationships between them. A three-dimensional third-order function is then fitted to these different mapping relationships to obtain a temperature compensation model, including:

[0113] The infrared thermal imaging lens was placed in a temperature-controlled chamber;

[0114] Adjust the temperature in the temperature chamber and the magnification of the infrared thermal imaging lens. For each set of temperature and magnification, obtain the modulation transfer function (MTF) curve of the target imaging. Based on the maximum value of the MTF curve at the cutoff frequency, determine the clear code value of the focusing motor corresponding to that set of temperature and magnification.

[0115] A three-dimensional third-order function is fitted to multiple different mapping relationships, and the coefficients of the three-dimensional third-order function are obtained by the least squares method, thus obtaining the temperature compensation model.

[0116] For example, a teleconverter or collimator can be used to simulate the calibration of the object distance.

[0117] For example, a long-wave infrared zoom lens with a focal length of f30-300mm was used as the calibration sample. The calibration object distance was set to 2000 meters, the magnification was set to 1-10x, and the temperature range of the temperature control chamber was set to -40℃ to 80℃. A collimator was used to simulate the calibration object distance of 2000 meters. At this calibration object distance, data was collected every 10℃. For each temperature, the sharpness code value of the focusing motor when the target was in sharp focus was obtained at each magnification. The sharpness code value of the focusing motor, temperature, and magnification at this calibration object distance were obtained, as shown in the table below. R in the table... i,j The clarity code value characterizes the focusing motor at different temperatures and magnifications.

[0118]

[0119] For example, based on the data obtained in the above manner, data simulation can be performed using optical simulation software to obtain the following results: Figure 3 The diagram shows the relationship between the sharpness value of the focusing motor and temperature and magnification, and the result is as follows: Figure 4 The diagram shown illustrates the relationship between the sharpness code value and magnification of the focusing motor, and the result is as follows: Figure 5 The diagram shows the relationship between the clarity code value of the focusing motor and the temperature.

[0120] For example, based on the above calibration method, multiple sets of data on the clarity code value, temperature, and magnification of the focusing motor are obtained. A three-dimensional third-order function (Polynomial three-dimensional function) is used for data fitting to establish a mapping relationship between the clarity code value of the focusing motor and the temperature and magnification. The function coefficients are determined using the least squares method to minimize the error between the obtained function value and the actual value, that is, to infinitely approximate the actual value, thus obtaining the temperature compensation model. The temperature compensation model is expressed as follows:

[0121] R(T,Z)=p 00 +p 10 *T+p 01 *Z+p 20 *T 2 +p 11 *T*Z+p 02 *Z 2 +p 30 *T 3 +p 21 *T 2 Z+p 12 *TZ 2 +p 03 *Z 3 ;

[0122] Where, p 00 p 10 p 01 p 20 p 11 p 02 p 30 p 21 p 12 p 03 The coefficients characterizing the temperature compensation model, R(T,Z) characterize the clear code value of the focusing motor at temperature T and magnification Z, where T represents the temperature variable and Z represents the magnification.

[0123] In this embodiment, the sharpness code value, temperature, and magnification data of the focusing motor are obtained through calibration. A three-dimensional third-order function is used to establish a mapping relationship between the sharpness code value of the focusing motor and the temperature and magnification. This allows the focusing motor to quickly obtain the corresponding sharpness code value when the lens temperature or magnification changes, so as to drive the focusing motor to move quickly to the corresponding position. This method does not require the calculation of defocus compensation, which greatly simplifies the calculation steps and has a small calculation error, enabling rapid temperature compensation for zoom lenses.

[0124] The pattern of sharpness code value of the focusing motor at different magnifications changing with temperature is fixed and determined by the optical design architecture of the infrared thermal imaging lens, i.e., the coefficient p in the temperature compensation model. 00 p 10 p 01 p20 p 11 p 02 p 30 p 21 p 12 p 03 It is fixed. The intersection of the sharpness code values ​​at different magnifications is the focal point, indicating that at that focal point, the image of the target object can always be sharp at different magnifications. The focal point is represented as (T, R), where T represents the focal point temperature and R represents the sharpness code value of the focusing motor corresponding to the focal point. For example... Figure 5 As shown, at a calibration object distance of 2000 meters, the lens at 20°C maintains the same focus motor sharpness code value at different magnifications, indicating the focal point. In this embodiment, T is 20°C and R is 4000. Zoom lenses are generally designed with 20°C as the theoretical focal point temperature. However, due to tolerances in lens manufacturing and assembly, such as lens thickness, eccentricity, surface shape, and air gaps, the focal point temperature can change. Therefore, during lens calibration, it is necessary to obtain the focal point error at any two magnifications and correct the focal point of the infrared thermal imaging lens based on this error.

[0125] For example, the focus error at any two magnifications can be obtained through calibration. Preferably, the sharpness code value of the focusing motor at the maximum magnification and the sharpness code value of the focusing motor at the minimum magnification are obtained, and the difference between these two sharpness code values ​​is used as the focus error at the current calibration temperature.

[0126] One embodiment of this application, as shown in 6, involves obtaining the focal point of an infrared thermal imaging lens and using the focal point as the focus compensation offset of a temperature compensation model, including steps S601-S607.

[0127] S601, for the current calibration temperature of the infrared thermal imaging lens, obtain the first clear code value of the focusing motor corresponding to the maximum magnification and the second clear code value of the focusing motor corresponding to the minimum magnification, and use the difference between the first clear code value and the second clear code value as the current parfocal error;

[0128] S602, if the current focus error is 0, use the current calibration temperature as the corrected focus temperature, and use the first clarity code value or the second clarity code value as the clarity code value of the corrected focus.

[0129] S603, if the current focus error is not 0, use optical simulation software to perform curve fitting on each calibration temperature and corresponding focus error based on the simulation software, and obtain the first focus temperature correction formula.

[0130] S604, based on the current calibration temperature, the current homofocal point error, and the first homofocal point temperature correction formula, determine the corrected homofocal point temperature;

[0131] S605, based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, determines the correction formula for the first cofocal clear code value;

[0132] S606, based on the first cofocal focal point sharpness code value correction formula and the current calibration temperature, determine the corrected cofocal focal point sharpness code value;

[0133] S607 uses the corrected parfocal temperature and the corrected parfocal sharpness code value as the focus compensation offset for the temperature compensation model.

[0134] For example, the maximum magnification Z is obtained for the current calibration temperature of the infrared thermal imaging lens. tele The first clear code value R of the corresponding focusing motor tele and minimum multiplier Z wide The corresponding second clarity code value R of the focusing motor wide The difference between the first and second clear code values ​​is taken as the current parfocal error ΔR. If ΔR = 0, the current calibration temperature is taken as the corrected parfocal temperature T0.

[0135] For example, if ΔR is not 0, using optical simulation software, based on the simulated calibration temperatures and corresponding parfocal errors, curve fitting is performed on each calibration temperature and its corresponding parfocal error to form a quadratic curve, thus obtaining the first parfocal temperature correction formula. Specifically, using optical simulation software, with the focal plane at maximum magnification as the zero point, the initial parfocal error and initial calibration temperature are set. By setting different calibration temperatures through the optical simulation software, the corresponding parfocal errors at different calibration temperatures can be obtained. For each calibration temperature, the difference between the sharpness code value of the focusing motor corresponding to the maximum magnification and the sharpness code value of the focusing motor corresponding to the minimum magnification is taken as the parfocal error corresponding to that calibration temperature. Based on the obtained calibration temperatures and their corresponding parfocal errors, an arithmetic progression array is constructed. The parfocal temperatures corresponding to a parfocal error of 0 are obtained as a set of data. The arithmetic progression array and this set of data are used to construct a data matrix. Curve fitting is performed on this data matrix to obtain the first parfocal temperature correction formula. The first parfocal temperature correction formula characterizes the mapping relationship between the corrected parfocal temperature and the current parfocal error and the current calibration temperature.

[0136] For example, the first cofocus temperature correction formula is expressed as:

[0137] T0=a1*(△R-(b1*T1*T1+b2*T1+b3)) 2+a2*(△R-(b1*T1*T1+b2*T1+b3+a3;

[0138] Where T0 represents the corrected focal point temperature, ΔR represents the current focal point error, a1, a2, a3, b1, b2, and b3 represent the coefficients of the first focal point temperature correction formula, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0139] Based on the current calibration temperature, the current homofocal error, and the aforementioned first homofocal temperature correction formula, the corrected homofocal temperature T0 is obtained. For example, substituting the current homofocal error and the current calibration temperature into the above formula yields the corrected homofocal temperature T0.

[0140] For example, based on the corrected parfocal temperature T0 and the first clear code value R tele Maximum multiplier Z tele And the temperature compensation model, determine the first cofocal focus sharpness code value correction formula. The first cofocal focus sharpness code value correction formula is expressed as:

[0141] R0=R)T0,Z tele )-R(T1, Z tele )+R tele =p 10 *(T0-T1)+p 20 *(T0 2 -T1 2 )+p 30 *(T0 3 -T1 3 )+p 11 *(T0-T1)*Z tele +p 21 *(T0 2 -T1 2 )Z tele +p 12 *(T0-T1)Z tele 2 +R tele ;

[0142] Where R0 represents the sharpness code value of the corrected cofocal point, T0 represents the corrected cofocal point temperature, and T1 represents the current calibration temperature of the infrared thermal imaging lens. tele Z represents the first clear code value. tele p represents the maximum magnification. 00 p 10 p 01 p 20 p 11 p 02 p 30 p 21 p12 p 03 The coefficients characterizing the temperature compensation model.

[0143] The derivation process of the formula for correcting the clear code value of the first cofocal focus is explained. Based on the formula R(T,Z) of the temperature compensation model mentioned above, the current calibration temperature T1 and the maximum magnification Z are used. tele Substituting into the formula R(T,Z), the current calibration temperature T1 and the maximum magnification Z can be calculated. tele The clear code value R(T1,Z) of the focusing motor under the current tele ), that is, R(T1,Z tele ) = R tele The corrected focal point temperature T0 and maximum magnification Z tele Substituting into the formula R(T,Z), the corrected focal spot temperature T0 and maximum magnification Z can be calculated. tele The clear code value R(T0,Z) of the focusing motor under the current tele ), that is, R(T0,Z tele =R0, the formula for correcting the first homofocal sharpness code value is R0 = R(T0, Z). tele )-R(T1,Z tele )+R tele =R0-R tele +R tele =R0, therefore the above formula for correcting the first co-focal clear code value is valid, and thus the above formula for correcting the first co-focal clear code value can be obtained.

[0144] As shown in the formula for correcting the focus point sharpness code value, the corrected focus point sharpness code value R0 is related to the corrected focus point temperature T0, the current calibration temperature T1, and the coefficients of the temperature compensation model. Since the coefficients of the temperature compensation model are known parameters, substituting the corrected focus point temperature T0 (calculated above) and the current calibration temperature T1 (a known quantity) into the formula yields the corrected focus point sharpness code value R0. The corrected focus point temperature T0 and the corrected focus point sharpness code value R0 are then used as the focus compensation offset for the temperature compensation model.

[0145] In this embodiment, optical simulation software is used to perform curve fitting on the simulated calibration temperatures and corresponding parfocal errors to obtain a first parfocal temperature correction formula. This corrects the parfocal temperature. Based on the temperature compensation model and the corrected parfocal temperature, a first parfocal sharpness code value correction formula is obtained, correcting the sharpness code value of the parfocal. This eliminates the influence of individual differences between different lenses on temperature compensation, ensuring the accuracy of temperature compensation. Selecting the difference between the sharpness code value of the focusing motor at maximum magnification and the sharpness code value of the focusing motor at minimum magnification makes the calculated corrected parfocal point more accurate.

[0146] One embodiment of this application, as shown in 7, involves obtaining the focal point of an infrared thermal imaging lens and using the focal point as the focus compensation offset of a temperature compensation model, including steps S701-S708.

[0147] S701: Based on the clear code values ​​of the focusing motors under multiple calibrated temperatures and magnifications, obtain the difference between the clear code value of the focusing motor corresponding to the highest temperature at the maximum magnification and the clear code value of the focusing motor corresponding to the lowest temperature. Calculate the ratio of this difference to the temperature difference between the highest and lowest temperatures to determine the high-value temperature compensation slope corresponding to the maximum magnification.

[0148] S702, obtain the difference between the clear code value of the focusing motor corresponding to the highest temperature at the minimum magnification and the clear code value of the focusing motor corresponding to the lowest temperature, calculate the ratio of this difference to the temperature difference between the highest and lowest temperatures, and determine the low-value temperature compensation slope corresponding to the minimum magnification.

[0149] S703, obtain the third clear code value of the focusing motor corresponding to the maximum magnification and the fourth clear code value of the focusing motor corresponding to the minimum magnification at the current calibration temperature, and use the difference between the third clear code value and the fourth clear code value as the current focus error;

[0150] S704, based on the current cofocal error, high-value temperature compensation slope and low-value temperature compensation slope, constructs a second cofocal temperature correction formula;

[0151] S705, Based on the current calibration temperature and the second focal point temperature correction formula, determine the corrected focal point temperature;

[0152] S706, using the corrected cofocal temperature, the third clear code value, and the high-value temperature compensation slope, constructs the second cofocal clear code value correction formula;

[0153] S707, based on the second cofocal focal point sharpness code value correction formula and the current calibration temperature, determines the corrected cofocal focal point sharpness code value;

[0154] S708 uses the corrected parfocal temperature and the corrected parfocal sharpness code value as the focus compensation offset for the temperature compensation model.

[0155] like Figure 5 As shown, the high-value temperature compensation slope corresponding to the maximum magnification of the zoom lens can be considered constant, and the low-value temperature compensation slope corresponding to the minimum magnification of the zoom lens can also be considered constant, which can be calculated from the calibration data of the zoom lens.

[0156] For example, taking the calibration data obtained in the table above as an example, a set of focus motor clear code values ​​R were obtained during the temperature change from -40℃ to 80℃ at the maximum magnification of 10. 1,10 R 2,10 ..., R 13,10 The focus motor clarity code value R corresponding to the highest temperature of 80℃ in this group of focus motor clarity code values. 13,10 The clear code value R of the focusing motor corresponding to the lowest temperature 1,10 The difference between the two values ​​is divided by the temperature difference (the temperature difference between -40℃ and 80℃) to obtain the corresponding high-value temperature compensation slope A1.

[0157] For example, taking the calibration data obtained in the table above as an example, a set of focusing motor clear code values ​​R were obtained during the temperature change from -40℃ to 80℃ at the minimum magnification of 1. 1,1 R 2,1 ..., R 13,1 The focus motor clarity code value R corresponding to the highest temperature of 80℃ in this group of focus motor clarity code values. 13,1 The clear code value R of the focusing motor corresponding to the lowest temperature 1,1 The difference between A1 and B1 is calculated by dividing the difference by the temperature difference (between -40℃ and 80℃) to obtain the corresponding low-temperature compensation slope B1, where A1 is greater than B1.

[0158] For example, the maximum magnification Z is determined based on the high-value temperature compensation slope A1. tele The corresponding clear code value R of the focusing motor tele The first relationship between the temperature and the current calibrated temperature T1 is expressed as:

[0159] R tele =A1*T1+A2;

[0160] Among them, R tele A1 represents the clear code value of the focusing motor corresponding to the maximum magnification, T represents the current calibration temperature, and A2 represents the coefficient of the first relation.

[0161] The minimum magnification Z is determined based on the low-value temperature compensation slope B1. wide The corresponding clear code value R of the focusing motor wide The second relationship between the temperature and the current calibrated temperature T is expressed as:

[0162] R wide =B1*T1+B2;

[0163] Among them, R wideB1 represents the clear code value of the focusing motor corresponding to the minimum magnification, T1 represents the low-value temperature compensation slope, and B2 represents the coefficient of the second relation.

[0164] Obtain the maximum magnification Z at the current calibration temperature. tele The corresponding third clarity code value R of the focusing motor tele Minimum multiplier Z wide The corresponding fourth clarity code value R of the focusing motor wide The difference between the third and fourth clarity code values ​​is used as the current cofocal error ΔR.

[0165] Substituting the current homofocal error ΔR into the first and second relations, we obtain:

[0166] △R=A1*T1-B1*T1+A2-B2;

[0167] Assuming the cofocal temperature is T0, R tele =R wide That is, △R=0, we get

[0168]

[0169] Based on the current homofocal error, the first relation, and the second relation, a second homofocal temperature correction formula is constructed, which is expressed as:

[0170]

[0171] Where T0 represents the corrected cofocal temperature, ΔR represents the current cofocal error, and T1 represents the current calibration temperature. Substituting the current cofocal error and the current calibration temperature into the second cofocal temperature correction formula, the corrected cofocal temperature T0 can be calculated. Using the corrected cofocal temperature T0 and the third clarity code value R... tele The high-value temperature compensation slope A1 is used to construct the second cofocal focus clear code value correction formula, which is expressed as:

[0172] R0=A1*(T0-T)+R tele ;

[0173] Where R0 represents the sharp code value of the corrected cofocal point, T1 represents the current calibration temperature, ΔR represents the current cofocal point error, and R tele Represents the third clarity code value.

[0174] The derivation process of the formula for correcting the sharpness code value of the second cofocal focal point is explained. From the first relation, it can be seen that the corrected sharpness code value R0 and the corrected cofocal focal point temperature T0 also satisfy the first relation, thus yielding Formula 1:

[0175] R0 = A1 * T0 + A2;

[0176] Subtracting Formula 1 from the first relational expression yields the second formula for correcting the clear code value of the co-focal point.

[0177] The corrected cofocal temperature T0, the current calibration temperature T1, and the third clarity code value R obtained from the above calculations are used. tele Substituting into the second cofocal focus sharpness code value correction formula, we can obtain the corrected cofocal focus sharpness code value R0. The corrected cofocal focus temperature T0 and the corrected cofocal focus sharpness code value R0 are used as the focus compensation offset for the temperature compensation model.

[0178] As can be seen from the above formula for correcting the second focal point clarity code value, the current focal point error ΔR is 0, which indicates that the current calibrated temperature is the corrected focal point temperature. When ΔR > 0, it indicates that the corrected focal point temperature of the zoom lens is less than the current calibrated temperature. When ΔR < 0, it indicates that the corrected focal point temperature of the zoom lens is greater than the current calibrated temperature.

[0179] In this embodiment, the corrected parfocal coordinates are determined based on the measured data during the lens calibration process. This method is simpler and more convenient to calculate, thereby eliminating the influence of individual differences between different lenses on temperature compensation and ensuring the accuracy of temperature compensation.

[0180] In one embodiment of this application, the temperature compensation model is modified using the clear code value of the homofocal point, the linear difference between the current temperature and the homofocal point temperature, to obtain a modified temperature compensation model, which is expressed as follows:

[0181] R(T,Z)=R0+p 10 *(T-T0)+p 20 *(T 2 -T0 2 )+p 30 *(T 3 -T0 3 )+p 11 *(T-T0)*Z+p 21 *(T 2 -T0 2 Z+p 12 *(T-T0)Z 2 ;

[0182] Where T represents the temperature variable, R0 represents the corrected clear code value of the cofocal point, T0 represents the corrected cofocal point temperature, Z represents the magnification, and p 10 p 20 p 30 p 11 p 21p 12 The coefficients characterize the temperature compensation model. T in this formula can be any temperature value, which can be non-integer or not a temperature recorded in the lens's factory-calibrated temperature matrix. Based on this formula, the sharpness code value of the focus motor after any temperature compensation can be calculated.

[0183] In this embodiment, the modified temperature compensation model takes into account the correction of the parfocal point, eliminating the impact of individual differences between different lenses on temperature compensation. Based on the modified temperature compensation model, according to the current temperature and current magnification of the infrared thermal imaging lens, the sharpness code value of the focusing motor after temperature compensation is obtained, driving the focusing motor to move to the corresponding position, thereby realizing temperature compensation for the zoom lens.

[0184] Figure 8 This is a schematic diagram of the structure of an infrared thermal imaging camera provided in an embodiment of this application. The camera includes:

[0185] Temperature sensor 801 is used to obtain the lens temperature;

[0186] Processor 802 is configured to execute computer-readable instructions to implement the temperature compensation method for the infrared thermal imaging lens as described above.

[0187] Specifically, when processor 802 executes computer-readable instructions, it performs the following steps:

[0188] The clear code values ​​of focusing motors under different temperatures and magnifications were calibrated to obtain the mapping relationship between the three. The three-dimensional third-order function was fitted to the different mapping relationships to obtain the temperature compensation model.

[0189] Obtain the focal point of the infrared thermal imaging lens, use the focal point as the focus compensation offset of the temperature compensation model, and correct the temperature compensation model to obtain the corrected temperature compensation model.

[0190] The current temperature and magnification of the infrared thermal imaging lens are obtained. Based on the current temperature, current magnification, and the corrected temperature compensation model, the clear code value of the focusing motor after temperature compensation is determined, and the focusing motor is controlled to drive to the position corresponding to the clear code value after temperature compensation.

[0191] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0192] The infrared thermal imaging lens was placed in a temperature-controlled chamber;

[0193] Adjust the temperature in the temperature chamber and the magnification of the infrared thermal imaging lens. For each set of temperature and magnification, obtain the modulation transfer function (MTF) curve of the target imaging. Based on the maximum value of the MTF curve at the cutoff frequency, determine the clear code value of the focusing motor corresponding to that set of temperature and magnification.

[0194] A three-dimensional third-order function is fitted to multiple different mapping relationships, and the coefficients of the three-dimensional third-order function are obtained by the least squares method, thus obtaining the temperature compensation model.

[0195] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0196] For the current calibration temperature of the infrared thermal imaging lens, the first clear code value of the focusing motor corresponding to the maximum magnification and the second clear code value of the focusing motor corresponding to the minimum magnification are obtained respectively, and the difference between the first clear code value and the second clear code value is used as the current parfocal error.

[0197] If the current focus error is 0, the current calibration temperature is used as the corrected focus temperature, and the first or second clarity code value is used as the clarity code value of the corrected focus.

[0198] If the current focal point error is not zero, use optical simulation software to perform curve fitting on each calibration temperature and corresponding focal point error based on the simulation software, and obtain the first focal point temperature correction formula.

[0199] Based on the current calibration temperature and the correction formula for the first focal point temperature, determine the corrected focal point temperature;

[0200] Based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, the correction formula for the first cofocal clear code value is determined.

[0201] Based on the first cofocal focal point sharpness code value correction formula and the current calibration temperature, determine the corrected cofocal focal point sharpness code value;

[0202] The corrected focal point temperature and the corrected focal point sharpness code value are used as the focus compensation offset of the temperature compensation model.

[0203] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0204] The correction formula for the temperature of the first cofocal point is expressed as follows:

[0205] T0=a1*(△R-(b1*T1*T1+b2*T1+b3)) 2 +a2*(△R-(b1*T1*T1+b2*T1+b3+a3;

[0206] Where T0 represents the corrected focal point temperature, ΔR represents the difference between the first and second clear code values, a1, a2, a3, b1, b2, and b3 represent the coefficients of the first focal point temperature correction formula, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0207] Based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, the correction formula for the first cofocal clear code value is determined, including:

[0208] The formula for correcting the first cofocal sharpness code value is expressed as follows:

[0209] R0 = R(T0, Z) tele )-R(T1, Z tele )+R tele

[0210] =p 10 *(T0-T1)+p 20 *(T0 2 -T1 2 )+p 30 *(T0 3 -T1 3 )+p 11 *(T0-T1)*Z tele +p 21 *(T0 2 -T1 2 )Z tele +p 12 *(T0-T1)Z tele 2 +R tele

[0211] Wherein, R0 represents the sharpness code value of the corrected cofocal point, T0 represents the corrected cofocal point temperature, T1 represents the current calibration temperature of the infrared thermal imaging lens, and R tele Z represents the first clear code value. tele p represents the maximum magnification. 10 p 20 p 30 p 11 p 21 p 12 The coefficients characterizing the temperature compensation model.

[0212] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0213] Based on the calibrated clear code values ​​of the focusing motors at different temperatures and magnifications, the difference between the clear code value of the focusing motor corresponding to the highest temperature at the maximum magnification and the clear code value of the focusing motor corresponding to the lowest temperature is obtained. The ratio of this difference to the temperature difference between the highest and lowest temperatures is calculated to determine the high-value temperature compensation slope corresponding to the maximum magnification.

[0214] Obtain the difference between the clear code value of the focusing motor corresponding to the highest temperature at the minimum magnification and the clear code value of the focusing motor corresponding to the lowest temperature. Calculate the ratio of this difference to the temperature difference between the highest and lowest temperatures to determine the low-value temperature compensation slope corresponding to the minimum magnification.

[0215] Obtain the third clear code value of the focusing motor corresponding to the maximum magnification at the current calibration temperature and the fourth clear code value of the focusing motor corresponding to the minimum magnification. Use the difference between the third clear code value and the fourth clear code value as the current parfocal error.

[0216] Based on the current cofocal error, the high-value temperature compensation slope, and the low-value temperature compensation slope, a second cofocal temperature correction formula is constructed.

[0217] Based on the current calibration temperature and the correction formula for the second cofocal point temperature, determine the corrected cofocal point temperature;

[0218] Using the corrected cofocal temperature, the third clear code value, and the high-value temperature compensation slope, a correction formula for the second cofocal clear code value is constructed.

[0219] Based on the second cofocal focal point sharpness code value correction formula and the current calibration temperature, determine the corrected cofocal focal point sharpness code value;

[0220] The corrected focal point temperature and the corrected focal point sharpness code value are used as the focus compensation offset of the temperature compensation model.

[0221] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0222] Based on the high-value temperature compensation slope, a first relationship is determined between the clear code value of the focusing motor corresponding to the maximum magnification and the calibration temperature, where the first relationship is expressed as:

[0223] R tele =A1*T+A2;

[0224] Among them, R tele A1 represents the sharp code value of the focusing motor corresponding to the maximum magnification, A1 represents the high-value temperature compensation slope, T1 represents the current calibration temperature of the infrared thermal imaging lens, and A2 represents the coefficient of the first relational expression.

[0225] Based on the low-value temperature compensation slope, a second relationship is determined between the clear code value of the focusing motor corresponding to the minimum magnification and the calibration temperature, whereby the second relationship is expressed as:

[0226] R wide =B1*T1+B2;

[0227] Among them, R wide B1 represents the clear code value of the focusing motor corresponding to the minimum magnification, B1 represents the low-value temperature compensation slope, T1 represents the current calibration temperature of the infrared thermal imaging lens, and B2 represents the coefficient of the second relation.

[0228] Based on the current homofocal error, the first relation, and the second relation, a second homofocal temperature correction formula is constructed, which is expressed as:

[0229]

[0230] Where T0 represents the corrected parfocal temperature, ΔR represents the current parfocal error, B1 represents the low-value temperature compensation slope, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0231] Using the corrected cofocal temperature, the third sharpness code value, and the high-temperature compensation slope, a formula for correcting the second cofocal sharpness code value is constructed, including:

[0232] Using the corrected cofocal temperature, the third sharpness code value, and the high-temperature compensation slope, a correction formula for the second cofocal sharpness code value is constructed. The second cofocal sharpness code value correction formula is expressed as follows:

[0233] R0 = A1*(T0-T1) + r tele ;

[0234] Where R0 represents the sharp code value of the corrected homofocal point, T0 represents the temperature of the corrected homofocal point, and R tele A1 represents the sharpness code value of the focusing motor corresponding to the maximum magnification, A1 represents the high-value temperature compensation slope, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

[0235] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0236] The temperature compensation model is modified using the clear code value of the homofocal focal point, the linear difference between the current temperature and the homofocal focal point temperature, resulting in the modified temperature compensation model expressed as follows:

[0237] R(T,Z)=R0+p 10 *(T-T0)+p 20 *(T 2 -T0 2 )+p30 *(T 3 -T0 3 )+p 11 *(T-T0)*Z+p 21 *(T 2 -T0 2 Z+p 12 *(T-T0)Z 2 ;

[0238] Where T represents temperature, R0 represents the corrected clear code value of the cofocal point, T0 represents the corrected cofocal point temperature, Z represents magnification, and p 10 p 20 p 30 p 11 p 21 p 12 The coefficients characterizing the temperature compensation model.

[0239] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0240] For each candidate object distance, the total depth of field range corresponding to the candidate object distance is calculated based on the aperture value, maximum focal length, focusing object distance, and mass circle diameter of the infrared thermal imaging lens.

[0241] Based on the total depth range corresponding to each candidate object distance calculated, if the overlapping depth between two adjacent total depth ranges is greater than a preset threshold, the two first candidate object distances corresponding to the two adjacent total depth ranges are obtained.

[0242] For the at least two first candidate object distances obtained, sort the first candidate object distances according to the distance between them;

[0243] The first candidate object distance is used as the calibration object distance, and the corrected temperature compensation model corresponding to each calibration object distance is determined according to the sorting of the first candidate object distances.

[0244] The system acquires the current object distance, current temperature, and current magnification of the infrared thermal imaging lens. Based on the current object distance, it selects the appropriate corrected temperature compensation model. Based on the current temperature, current magnification, and the selected corrected temperature compensation model, it determines the temperature-compensated sharpness code value of the focusing motor and controls the focusing motor to drive to the position corresponding to the temperature-compensated sharpness code value.

[0245] Preferably, when the processor 802 executes computer-readable instructions, it performs the following steps:

[0246] Without a ranging module, the infrared thermal imaging lens acquires its corresponding corrected temperature compensation model at at least three different calibration distance points.

[0247] The object distance of the infrared thermal imaging lens is adjusted to each of the three calibration object distance points from far to near. At each calibration object distance point, the corresponding corrected temperature compensation model is called to obtain the clarity code value corresponding to the current temperature. The focusing motor is driven to move to the clarity code value. If the clarity of the corresponding captured image is lower than the preset clarity threshold, the object distance of the infrared thermal imaging lens is moved to the next calibration object distance point until the clarity of the corresponding captured image is higher than the preset clarity threshold. The corresponding calibration object distance point is set as the optimal object distance point, and the corresponding corrected temperature compensation model is obtained based on the optimal object distance point.

[0248] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above-described infrared thermal imaging lens temperature compensation methods.

[0249] Figure 9 This is a schematic diagram of the hardware structure of a computer device provided in an embodiment of this application. Figure 9 The computer device shown includes: a processor 901, a communication interface 902, a memory 903, and a communication bus 904. The processor 901, communication interface 902, and memory 903 communicate with each other via the communication bus 904. Figure 9 The connection method between the processor 901, communication interface 902, and memory 903 shown is merely exemplary. In the implementation process, the processor 901, communication interface 902, and memory 903 can also communicate with each other using other connection methods besides the communication bus 904.

[0250] The memory 903 can be used to store computer programs, which may include instructions and data to implement the steps of any of the above-described infrared thermal imaging lens temperature compensation methods. In this embodiment, the memory 903 can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), flash memory, optical memory, and registers. The memory 903 may include a hard disk and / or RAM.

[0251] Processor 901 can be a general-purpose processor, which can be a processor that performs specific steps and / or operations by reading and executing a computer program (e.g., a computer program) stored in memory (e.g., memory 903). The general-purpose processor may use data stored in memory (e.g., memory 903) during the execution of said steps and / or operations. The general-purpose processor can be, for example, but not limited to, a central processing unit (CPU). Furthermore, processor 901 can also be a special-purpose processor, which can be a processor specifically designed to perform specific steps and / or operations. Special-purpose processors can be, for example, but not limited to, ASICs and FPGAs. Additionally, processor 901 can also be a combination of multiple processors, such as a multi-core processor.

[0252] Communication interface 902 may include input / output (I / O) interfaces, physical interfaces, and logical interfaces for interconnecting devices within the network device, as well as interfaces for interconnecting the network device with other devices (e.g., network devices). The communication network may be Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc. Communication interface 902 may be a module, circuit, transceiver, or any device capable of enabling communication.

[0253] In implementation, each step of the above method can be completed by the integrated logic circuitry of the hardware in the processor 901 or by instructions in software form. The method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory (RAM), read-only memory (ROM), programmable read-only memory (ROM), electrically erasable programmable memory (EPR), registers, or other mature storage media in the art. This storage medium is located in memory 903, and the processor 901 reads the information in memory 903 and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0254] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, representing three possible relationships. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more detailed understanding.

[0255] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0256] The communication bus mentioned in the aforementioned electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.

[0257] The communication interface is used for communication between the aforementioned electronic device and other devices. The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor. The aforementioned processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0258] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0259] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0260] The above are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application. Based on the same inventive concept, embodiments of this application also provide an electronic device, including: at least one memory and at least one processor, wherein the at least one memory stores executable code, and the at least one processor is used to execute the executable code in the at least one memory to implement the above-described image restoration model training method and / or image restoration method.

Claims

1. A method of temperature compensation for an infrared thermal imaging lens, characterized by, The method includes: The clear code values ​​of focusing motors under different temperatures and magnifications were calibrated to obtain the mapping relationship between the three. Curve fitting was performed on the different mapping relationships to obtain the temperature compensation model. Obtain the focal point of the infrared thermal imaging lens, use the focal point as the focus compensation offset of the temperature compensation model, and correct the temperature compensation model to obtain the corrected temperature compensation model. The current temperature and current magnification of the infrared thermal imaging lens are obtained. Based on the current temperature, current magnification and the corrected temperature compensation model, the temperature-compensated sharpness code value of the focusing motor is determined, and the focusing motor is controlled to drive to the position corresponding to the temperature-compensated sharpness code value.

2. The method of claim 1, wherein, Calibrate the clear code values ​​of focusing motors under different temperatures and magnifications to obtain the mapping relationship between them and the three factors. Perform three-dimensional third-order function fitting on multiple different mapping relationships to obtain a temperature compensation model, including: The infrared thermal imaging lens was placed in a temperature-controlled chamber. Adjust the temperature in the temperature regulating chamber and the magnification of the infrared thermal imaging lens. For each set of temperature and magnification, obtain the modulation transfer function (MTF) curve of the target imaging. Based on the maximum value of the MTF curve at the cutoff frequency, determine the clear code value of the focusing motor corresponding to that set of temperature and magnification. The temperature compensation model is obtained by fitting three-dimensional third-order functions to multiple different mapping relationships and obtaining the coefficients of the three-dimensional third-order functions through the least squares method.

3. The method of claim 1, wherein, Obtaining the homofocal point of the infrared thermal imaging lens, and using the homofocal point as the focus compensation offset of the temperature compensation model, includes: For the current calibration temperature of the infrared thermal imaging lens, the first clear code value of the focusing motor corresponding to the maximum magnification and the second clear code value of the focusing motor corresponding to the minimum magnification are obtained respectively, and the difference between the first clear code value and the second clear code value is used as the current parfocal error. If the current focus error is 0, the current calibration temperature is used as the corrected focus temperature, and the first clarity code value or the second clarity code value is used as the clarity code value of the corrected focus. If the current focal point error is not zero, use optical simulation software to perform curve fitting on each calibration temperature and corresponding focal point error based on the simulation of each calibration temperature and corresponding focal point error by the optical simulation software, and obtain the first focal point temperature correction formula. Based on the current calibration temperature, the current cofocal point error, and the first cofocal point temperature correction formula, the corrected cofocal point temperature is determined; Based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, the correction formula for the first cofocal clear code value is determined. Based on the first clear code value correction formula of the homofocal focal point and the current calibration temperature, the clear code value of the homofocal focal point after correction is determined; The corrected parfocal temperature and the corrected parfocal sharpness code value are used as the focus compensation offset of the temperature compensation model.

4. The method of claim 3, wherein, Based on the various calibration temperatures simulated by the optical simulation software, curve fitting is performed on each calibration temperature and the parfocal error to obtain the first parfocal temperature correction formula, including: The formula for correcting the temperature of the first cofocal point is expressed as follows: T0=a1*(△R-(b1*T1*T1+b2*T1+b3)) 2 +a2*(△R-(b1*T1*T1+b2*T1+b3+a3; Where T0 represents the corrected focal point temperature, ΔR represents the difference between the first and second clear code values, a1, a2, a3, b1, b2, and b3 represent the coefficients of the first focal point temperature correction formula, and T1 represents the current calibration temperature of the infrared thermal imaging lens. Based on the corrected cofocal temperature, the first clear code value, the maximum magnification, and the temperature compensation model, the correction formula for the first cofocal clear code value is determined, including: The formula for correcting the first cofocal sharpness code value is expressed as follows: R0=p 10 *(T0-T1)+p 20 *(T0 2 -T1 2 )+p 30 *(T0 3 -T1 3 )+p 11 *(T0-T1)*Z tele +p 21 *(T0 2 -T1 2 )Z tele +p 12 *(T0-T1)Z tele 2 +R tele ; Where R0 represents the sharpness code value of the corrected cofocal point, T0 represents the corrected cofocal point temperature, and T1 represents the current calibration temperature of the infrared thermal imaging lens. tele Z represents the first clear code value. tele p represents the maximum magnification. 10 p 20 p 30 p 11 p 21 p 12 The coefficients characterizing the temperature compensation model.

5. The method of claim 1, wherein, Obtaining the homofocal point of the infrared thermal imaging lens, and using the homofocal point as the focus compensation offset of the temperature compensation model, includes: Based on the calibrated clear code values ​​of the focusing motors at different temperatures and magnifications, the difference between the clear code value of the focusing motor corresponding to the highest temperature at the maximum magnification and the clear code value of the focusing motor corresponding to the lowest temperature is obtained. The ratio of this difference to the temperature difference between the highest and lowest temperatures is calculated to determine the high-value temperature compensation slope corresponding to the maximum magnification. Obtain the difference between the clear code value of the focusing motor corresponding to the highest temperature at the minimum magnification and the clear code value of the focusing motor corresponding to the lowest temperature. Calculate the ratio of this difference to the temperature difference between the highest and lowest temperatures to determine the low-value temperature compensation slope corresponding to the minimum magnification. Obtain the third clear code value of the focusing motor corresponding to the maximum magnification at the current calibration temperature and the fourth clear code value of the focusing motor corresponding to the minimum magnification. Use the difference between the third clear code value and the fourth clear code value as the current parfocal error. Based on the current cofocal error, the high-value temperature compensation slope, and the low-value temperature compensation slope, a second cofocal temperature correction formula is constructed. Based on the current calibration temperature and the second homofocal point temperature correction formula, the corrected homofocal point temperature is determined; Using the corrected focal point temperature, the third clear code value, and the high-value temperature compensation slope, a second focal point clear code value correction formula is constructed. Based on the second cofocal focus clarity code value correction formula and the current calibration temperature, the corrected cofocal focus clarity code value is determined; The corrected parfocal temperature and the corrected parfocal sharpness code value are used as the focus compensation offset of the temperature compensation model.

6. The method of claim 5, wherein, Based on the current cofocal point error, the high-value temperature compensation slope, and the low-value temperature compensation slope, a second cofocal point temperature correction formula is constructed, including: Based on the high-value temperature compensation slope, a first relationship is determined between the clear code value of the focusing motor corresponding to the maximum magnification and the calibration temperature, where the first relationship is expressed as: R tele = A1*T1 + A2; Among them, R tele A1 represents the sharp code value of the focusing motor corresponding to the maximum magnification, A1 represents the high-value temperature compensation slope, T1 represents the current calibration temperature of the infrared thermal imaging lens, and A2 represents the coefficient of the first relational expression. Based on the low-value temperature compensation slope, a second relationship is determined between the clear code value of the focusing motor corresponding to the minimum magnification and the calibration temperature, whereby the second relationship is expressed as: R wide = B1*T1 + B2; Among them, R wide B1 represents the clear code value of the focusing motor corresponding to the minimum magnification, B1 represents the low-value temperature compensation slope, T1 represents the current calibration temperature of the infrared thermal imaging lens, and B2 represents the coefficient of the second relation. Based on the current homofocal error, the first relation, and the second relation, a second homofocal temperature correction formula is constructed, which is expressed as: Where T0 represents the corrected parfocal temperature, ΔR represents the current parfocal error, A1 represents the high-value temperature compensation slope, B1 represents the low-value temperature compensation slope, and T1 represents the current calibration temperature of the infrared thermal imaging lens. Using the corrected cofocal temperature, the third sharpness code value, and the high-temperature compensation slope, a second cofocal sharpness code value correction formula is constructed, including: Using the corrected cofocal temperature, the third sharpness code value, and the high-temperature compensation slope, a second cofocal sharpness code value correction formula is constructed, which is expressed as: R0 = A1 * (T0 - T1) + R tele ; Where R0 represents the sharp code value of the corrected homofocal point, T0 represents the temperature of the corrected homofocal point, and R tele A1 represents the sharpness code value of the focusing motor corresponding to the maximum magnification, A1 represents the high-value temperature compensation slope, and T1 represents the current calibration temperature of the infrared thermal imaging lens.

7. The method of claim 1, wherein, Using the homofocal point as the focus compensation offset of the temperature compensation model, the temperature compensation model is corrected to obtain the corrected temperature compensation model, including: The temperature compensation model is modified using the clear code value of the homofocal point, the linear difference between the current temperature and the homofocal point temperature, to obtain the modified temperature compensation model: R(T,Z)=R0+p 10 *(T-T0)+p 20 *(T 2 -T0 2 )+p 30 *(T 3 -T0 3 )+p 11 *(T-T0)*Z+p 21 *(T 2 -T0 2 )Z+p 12 *(T-T0)Z 2 ; Where T represents the temperature variable, R0 represents the corrected clear code value of the cofocal point, T0 represents the corrected cofocal point temperature, Z represents the magnification, and p 10 p 20 p 30 p 11 p 21 p 12 The coefficients characterizing the temperature compensation model.

8. The method of claim 1, wherein, The method further includes: For each candidate object distance, the total depth of field range corresponding to the candidate object distance is calculated based on the aperture value of the infrared thermal imaging lens, the maximum magnification of the focal length, the candidate object distance, and the diameter of the mass circle. Based on the total depth range corresponding to each candidate object distance calculated, if the overlapping depth between two adjacent total depth ranges is greater than a preset threshold, two first candidate object distances corresponding to the two adjacent total depth ranges are obtained. For the at least two first candidate object distances obtained, sort the first candidate object distances according to the distance between them; The first candidate object distance is used as the calibration object distance, and the corrected temperature compensation model corresponding to each calibration object distance is determined according to the order of the first candidate object distances. The current object distance, current temperature, and current magnification of the infrared thermal imaging lens are obtained. Based on the current object distance, a corresponding corrected temperature compensation model is selected. Based on the current temperature, current magnification, and the selected corrected temperature compensation model, the temperature-compensated sharpness code value of the focusing motor is determined. The focusing motor is then controlled to drive to the position corresponding to the temperature-compensated sharpness code value.

9. The method of claim 8, wherein, The method further includes: Without a ranging module, the infrared thermal imaging lens acquires corresponding corrected temperature compensation models at at least three different calibration distance points. The object distance of the infrared thermal imaging lens is adjusted to each of the three calibration object distance points from farthest to closest. At each calibration object distance point, the corresponding corrected temperature compensation model is invoked to obtain the clarity code value corresponding to the current temperature. The focusing motor is driven to move to the clarity code value. If the clarity of the corresponding captured image is lower than a preset clarity threshold, the object distance of the infrared thermal imaging lens is moved to the next calibration object distance point until the clarity of the corresponding captured image is higher than the preset clarity threshold. The corresponding calibration object distance point is then set as the optimal object distance point, and the corresponding corrected temperature compensation model is obtained based on the optimal object distance point.

10. An infrared thermal imaging camera characterized by, The camera includes: A temperature sensor is used to obtain the lens temperature; A processor for executing computer-readable instructions to implement the temperature compensation method for an infrared thermal imaging lens as described in any one of claims 1 to 9.

Images