Infrared equipment temperature self-calibration method

Abstract

The invention relates to a temperature self-calibration method for infrared equipment. The method comprises the following steps: establishing a T-X curve lookup table of built-in shutter temperature and built-in shutter AD mean value of the infrared equipment in a reference state; acquiring the temperature of the built-in shutter of the infrared equipment and the average values # imgabs0 # and # imgabs1 # of the AD of the built-in shutter in real time; according to the built-in shutter temperatures # imgabs2 # and # imgabs3 #, the T-X curve lookup table is inquired, and the AD mean values # imgabs4 # and # imgabs5 # of the built-in shutters in the reference state are obtained through calculation; calculating calibration parameters through the average values # imgabs6 # and # imgabs7 # of the built-in shutter AD and the average values # imgabs8 # and # imgabs9 # of the built-in shutter AD in the reference state; and performing temperature calibration by using the calibration coefficient. Temperature self-calibration is carried out through the built-in shutter of the infrared equipment without depending on an external temperature source, so that the temperature calibration cost is saved, and the temperature calibration efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of infrared temperature measurement, and in particular relates to a method for self-calibration of temperature of infrared equipment. Background Art

[0002] After long-term operation, infrared equipment such as infrared thermal imagers need to be regularly calibrated due to the characteristics of the detector. Existing infrared equipment temperature calibration technology is mainly based on external standard temperature sources, such as standard radiation source calibration (blackbody calibration), ambient temperature calibration (external temperature sensor), etc. However, the standard radiation source calibration method requires the equipment to be disassembled, calibrated, and reinstalled, or the standard radiation source must be transported to the infrared thermal imager installation site for calibration, which is difficult and costly. The external temperature sensor calibration method is easily affected by the environment and has low calibration reliability. Summary of the invention

[0003] In view of the technical problems raised above, the present invention provides a method and method for self-calibration of temperature of infrared equipment, aiming to solve the problems of high cost and low efficiency of temperature automatic calibration.

[0004] In a first aspect, the present invention provides a method for self-calibration of temperature of an infrared device, the method comprising:

[0005] Step S1: Establishing a TX curve lookup table of the built-in shutter temperature of the infrared device in the reference state and the built-in shutter AD average value;

[0006] Step S2: Real-time acquisition of the built-in shutter temperature of the infrared device and built-in shutter AD average ;

[0007] Step S3: According to the built-in shutter temperature , query the TX curve lookup table to calculate the reference state built-in shutter AD average value ;

[0008] Step S4: Using the built-in shutter AD average , Baseline state built-in shutter AD average Calculate calibration parameters;

[0009] Step S5: Perform temperature calibration using the calibration coefficient.

[0010] Furthermore, the built-in shutter temperature and the built-in shutter AD average are respectively collected by the built-in shutter temperature sensor and the infrared detector of the infrared device.

[0011] Furthermore, the step S1 establishes a TX curve lookup table of the built-in shutter temperature of the infrared device in the reference state and the built-in shutter AD average value, specifically:

[0012] Collect and record the built-in shutter temperature T and the built-in shutter AD average value X;

[0013] The TX curve is obtained by piecewise fitting of quadratic function;

[0014] A TX curve lookup table is established using the shutter temperature and the quadratic term coefficient of the quadratic function.

[0015] Furthermore, the specific calculation formula for obtaining the TX curve by fitting the quadratic function is:

[0016]

[0017] In the above formula, is the average value of built-in shutter AD, is the built-in shutter temperature, is the coefficient of the quadratic term.

[0018] Furthermore, the use of the shutter temperature and the quadratic coefficient of the quadratic function to establish a TX curve lookup table is specifically as follows: Four-dimensional relationship table.

[0019] Further, the step S3 is based on the built-in shutter temperature , query the TX curve lookup table to calculate the average AD value of the built-in shutter of the infrared device in the reference state Specifically:

[0020] According to the built-in shutter temperature , query the TX curve lookup table to get the corresponding quadratic coefficient , ;

[0021] The corresponding .

[0022] Furthermore, the calibration parameters and the built-in shutter AD mean and built-in shutter AD average The calibration parameter is inversely proportional to the difference between the built-in shutter AD mean value of the reference state And the average value of the built-in shutter AD in the baseline state is proportional to the difference.

[0023] Furthermore, the specific calculation formula of the calibration parameter is:

[0024]

[0025] In the above formula, is the calibration parameter, It is the average of two built-in shutter AD values ​​collected in real time. It is the corresponding reference state built-in shutter AD average value.

[0026] Furthermore, the step S4 uses the calibration coefficient to perform temperature calibration specifically as follows:

[0027] Correct the target AD mean using the calibration factor;

[0028] The corrected target AD mean value is converted into a target temperature through the TX curve lookup table.

[0029] Furthermore, the specific calculation formula for correcting the target AD mean using the calibration coefficient is:

[0030]

[0031] In the above formula, is the corrected target AD mean, is the target AD mean before correction, is the calibration parameter.

[0032] Compared with the prior art, the beneficial effects of the present invention are: temperature self-calibration is performed through the built-in shutter of the infrared device, and there is no need to rely on external temperature sources such as standard radiation sources or external temperature sensors for calibration, thereby saving temperature calibration costs and improving temperature calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0034] Figure 1 A flow chart of a method for self-calibration of temperature of an infrared device according to the present invention;

[0035] Figure 2 is a relationship diagram between the built-in shutter temperature and the built-in shutter AD mean value of the present invention;

[0036] Figure 3 The TX curve is obtained by piecewise fitting of a quadratic function according to the present invention; DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the specific embodiments described herein are only used to explain the present invention and are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] Infrared equipment

[0040] Figure 1 The embodiment of the present invention is related to a method for self-calibration of temperature of an infrared device, the method comprising:

[0041] Step S1: Establishing a TX curve lookup table of the built-in shutter temperature of the infrared device in the reference state and the built-in shutter AD average value;

[0042] Specifically, first, the built-in shutter temperature and the built-in shutter AD average are collected through the built-in shutter temperature sensor and infrared detector of the infrared device. The values ​​of T and X are recorded once every certain time interval through the software. In a NUC closed loop (NUC closed loop refers to the pull-down action to deal with the drift of the detector AD value) cycle, T and X have a quadratic relationship, such as Figure 2 The infrared device in the present invention can be in an online state or an offline state.

[0043] Secondly, in every two adjacent closed-loop intervals, the function expression of X with respect to T can be obtained by fitting a quadratic function: Formula (1)

[0044] In the above formula, is the average value of built-in shutter AD, is the built-in shutter temperature, is the coefficient of the quadratic term. *100 is the horizontal axis, As the vertical axis, the TX curve fitted by the above steps is as follows Figure 3 shown.

[0045] Finally, divide the N TX curves according to the shutter temperature when the NUC is closed loop, and convert the built-in shutter temperature (*100), the quadratic coefficient , written into the array respectively as the reference state TX curve lookup table p_table.

[0046] Taking the infrared thermal imager device as an example, by collecting the TX curve lookup table of the built-in shutter temperature and the built-in shutter AD average and preprocessing, its reference state TX curve lookup table p_table is obtained, as shown in the following table.

[0047]

[0048] Step S2: Real-time acquisition of the built-in shutter temperature of the infrared device and built-in shutter AD average ;

[0049] Specifically, the temperature measurement results of the infrared device in the initial state are the most accurate, as shown in Table 1:

[0050]

[0051] After the device has been running for a period of time, the temperature measurement results of the infrared device will produce errors, as shown in Table 2:

[0052]

[0053] Therefore, when the temperature measurement error is greater than a certain threshold, the infrared device requests calibration and collects the built-in shutter temperature of the infrared device in real time. and built-in shutter AD average ; The temperature of the built-in shutter is two times with a certain temperature difference.

[0054] Step S3: According to the built-in shutter temperature , query the TX curve lookup table to calculate the reference state built-in shutter AD average value ;

[0055] Specifically, according to the built-in shutter temperature , query the TX curve lookup table to get the corresponding quadratic coefficient , ; The corresponding .

[0056] Step S4: Using the built-in shutter AD average , Baseline state built-in shutter AD average Calculate calibration parameters;

[0057] Specifically, the specific calculation formula of the calibration parameter is:

[0058] Formula (2)

[0059] In the above formula, is the calibration parameter, It is the average of two built-in shutter AD values ​​collected in real time. It is the corresponding reference state built-in shutter AD average value.

[0060] Step S5: Perform temperature calibration using the calibration coefficient.

[0061] Specifically, the calibration coefficient is used to correct the target AD mean, and the specific calculation formula is:

[0062] Formula (3)

[0063] In the above formula, is the corrected target AD mean, is the target AD mean before correction, To calibrate the parameters, the corrected target AD mean is converted into the target temperature through the TX curve lookup table. The calibrated temperature measurement structure is shown in Table 3.

[0064]

[0065] The results show that the temperature measurement accuracy of the infrared device is improved from ±3% to ±1% compared with the uncalibrated state, that is, the accuracy of the temperature measurement result of the calibrated infrared device is significantly improved. In addition, the present invention performs temperature self-calibration based on the built-in shutter of the infrared thermal imager, and does not need to rely on external temperature sources such as standard radiation sources or external temperature sensors for calibration, thus saving the cost of infrared device temperature calibration.

[0066] The above embodiments only express the preferred implementation mode of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for self-calibration of infrared device temperature, characterized in that: The following steps are involved: Step S1: Establishing a TX curve lookup table of the built-in shutter temperature of the infrared device in the reference state and the built-in shutter AD average value; Step S2: Real-time acquisition of the built-in shutter temperature of the infrared device , and built-in shutter AD average , ; Step S3: According to the built-in shutter temperature , , query the TX curve lookup table to calculate the reference state built-in shutter AD average value , ; Step S4: Using the built-in shutter AD average , , Baseline state built-in shutter AD average , Calculate calibration parameters; Step S5: Perform temperature calibration using the calibration coefficient.

2. The method for self-calibration of infrared device temperature according to claim 1, characterized in that: The built-in shutter temperature and the built-in shutter AD average are collected respectively through the built-in shutter temperature sensor and the infrared detector of the infrared device.

3. The method for self-calibration of infrared device temperature according to claim 2, characterized in that: The step S1 establishes a TX curve lookup table of the built-in shutter temperature of the infrared device in the reference state and the built-in shutter AD average value, specifically: Collect and record the built-in shutter temperature T and the built-in shutter AD average value X; The TX curve is obtained by piecewise fitting of quadratic function; A TX curve lookup table is established using the shutter temperature and the quadratic term coefficient of the quadratic function.

4. The method for self-calibration of infrared device temperature according to claim 3, characterized in that: The specific calculation formula for the TX curve obtained by quadratic function fitting is: In the above formula, is the average value of built-in shutter AD, is the built-in shutter temperature, is the coefficient of the quadratic term.

5. The method for self-calibration of infrared device temperature according to claim 4, characterized in that: The use of the shutter temperature and the quadratic coefficient of the quadratic function to establish a TX curve lookup table is specifically as follows: Four-dimensional relationship table.

6. The method for self-calibration of infrared device temperature according to claim 5, characterized in that: The step S3 is based on the built-in shutter temperature , , query the TX curve lookup table to calculate the average AD value of the built-in shutter of the infrared device in the reference state , Specifically: According to the built-in shutter temperature , , query the TX curve lookup table to get the corresponding quadratic coefficient ,; The corresponding , .

7. The method for self-calibration of infrared device temperature according to claim 6, characterized in that: The calibration parameters are compared with the built-in shutter AD mean and built-in shutter AD average The calibration parameter is inversely proportional to the difference between the built-in shutter AD mean value of the reference state And the average value of the built-in shutter AD in the baseline state is proportional to the difference.

8. The method for self-calibration of infrared device temperature according to claim 7, characterized in that: The specific calculation formula of the calibration parameters is: In the above formula, is the calibration parameter, It is the average of two built-in shutter AD values ​​collected in real time. It is the corresponding reference state built-in shutter AD average value.

9. The method for self-calibration of infrared device temperature according to claim 8, characterized in that: The step S4 uses the calibration coefficient to perform temperature calibration specifically as follows: Correct the target AD mean using the calibration factor; The corrected target AD mean value is converted into a target temperature through the TX curve lookup table.

10. The infrared temperature measurement correction method based on the radiation source size effect according to claim 9, characterized in that: The specific calculation formula for correcting the target AD mean using the calibration coefficient is: In the above formula, is the corrected target AD mean, is the target AD mean before correction, is the calibration parameter.

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