CN111609937B - Thermal infrared imager external field calibration method and device - Google Patents
- ️Tue Jul 20 2021
CN111609937B - Thermal infrared imager external field calibration method and device - Google Patents
Thermal infrared imager external field calibration method and device Download PDFInfo
-
Publication number
- CN111609937B CN111609937B CN202010511198.5A CN202010511198A CN111609937B CN 111609937 B CN111609937 B CN 111609937B CN 202010511198 A CN202010511198 A CN 202010511198A CN 111609937 B CN111609937 B CN 111609937B Authority
- CN
- China Prior art keywords
- thermal infrared
- infrared imager
- temperature
- integration time
- black body Prior art date
- 2020-06-08 Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/80—Calibration
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Radiation Pyrometers (AREA)
Abstract
The invention relates to a method and a device for calibrating an external field of a thermal infrared imager, computer equipment and a computer readable storage medium, wherein the method comprises the following steps: determining an integration time lower limit value and an integration time upper limit value used for collecting calibration data according to the environment temperature of the external field; determining a lower temperature limit point and an upper temperature limit point used for acquiring calibration data; setting the camera integral time of the thermal infrared imager as an integral time lower limit value, respectively collecting and storing output images corresponding to the temperature lower limit point and the temperature upper limit point, changing the camera integral time as an integral time upper limit value, and collecting and storing output images corresponding to the ambient temperature; solving the responsivity of the thermal infrared imager, the bias caused by stray radiation and the bias caused by the dark current of the thermal infrared imager according to the gray level of the stored image; and obtaining a calibration curve according to a calibration formula covering the integral time variable, outputting the calibration curve and completing calibration. The invention can realize the quick calibration of any integration time in a certain range under the external field condition.
Description
Technical Field
The invention relates to the technical field of infrared detection, in particular to a thermal infrared imager external field calibration method and device, computer equipment and a computer readable storage medium.
Background
The infrared imaging technology has the advantages of being strong in anti-interference and penetrating capability, small in influence of rain, fog and haze weather, capable of providing all-weather services and the like, and is more and more widely applied. In order to accurately complete the infrared radiation characteristic measurement of the target, the thermal infrared imager needs to be radiometrically calibrated. Currently, there are two general ways for radiometric calibration of thermal infrared imagers: laboratory calibration and external field calibration. The laboratory calibration is radiation calibration performed in a stable laboratory environment, and calibration data are good in repeated stability and high in calibration precision. The external field calibration is to correct the external field environment according to the infrared radiation characteristic of the actually measured target on the basis of laboratory calibration, and mainly aims to correct the influence of the environmental temperature change on the measurement result. When the infrared radiation characteristic of the target is measured, in order to improve the signal-to-noise ratio, a proper integration time needs to be selected according to the radiation characteristic of the target, so that during radiation calibration, radiation calibration data under all required integration times should be acquired, which is a tedious work, time-consuming and labor-consuming, and the preparation time for external field measurement is limited, so that a tedious and complicated calibration process is difficult to perform.
Therefore, in order to overcome the above disadvantages, a simpler, faster and more convenient outfield calibration method needs to be provided.
Disclosure of Invention
Technical problem to be solved
The invention aims to solve the technical problems of complicated external field calibration process and long consumed time of the thermal infrared imager in the prior art.
(II) technical scheme
In order to solve the technical problem, the invention provides a thermal infrared imager external field calibration method, which comprises the following steps:
s1, determining the lower limit value I of the integration time used for collecting the calibration data according to the environment temperature Te of the external field1And an upper limit value I of integration time2；
S2, determining a temperature lower limit point T used for collecting calibration data according to the ambient temperature Te of the external field1And upper temperature limit point T2；
S3, setting the camera integration time of the thermal infrared imager as the integration time lower limit value I1Respectively collecting and storing the lower temperature limit point T of the thermal infrared imager1And upper temperature limit point T2Changing the integration time of the camera to an upper limit value I of the integration time corresponding to the output image2Collecting and storing an image correspondingly output by the thermal infrared imager at the ambient temperature Te;
s4, solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager according to the gray level of the stored image;
s5, obtaining a calibration curve according to a calibration formula h ═ I × (G × L + O) + b covering the integral time variable, outputting the calibration curve, and completing calibration; wherein h is the gray scale of the image output by the thermal infrared imager, I is the camera integration time, and L is the radiance.
Preferably, a surface source black body is adopted to provide a lower limit point T of temperature1Upper limit of temperature T2And infrared radiation corresponding to the ambient temperature Te.
Preferably, the step S1 includes the steps of:
s11, starting a surface source black body, and setting the temperature of the surface source black body as the ambient temperature Te of the external field at the moment;
s12, starting the thermal infrared imager for measurement, adjusting the thermal infrared imager to be aligned to the radiation surface of the surface source black body, and ensuring that the radiation surface is full of the field of view of the thermal infrared imager;
s13, checking the gray median hm of the image corresponding to the surface source black body at the moment, adjusting the camera integration time to enable hm to be hmax/2, wherein hmax is the maximum value of the gray scale which can be output by the thermal infrared imager, and recording the integration time Im at the moment;
s14, determining the lower limit value I of the integration time used for collecting the calibration data1And an upper limit value I of integration time2，I1＝0.5×Im，I2＝1.5×Im。
Preferably, in step S2, the lower temperature limit T used for collecting calibration data is determined1And upper temperature limit point T2When, T1＝Te-20℃，T2＝Te+20℃。
Preferably, the step S3 includes the steps of:
s31, starting the thermal infrared imager, stably operating the thermal infrared imager in an external field environment for more than 30 minutes, and setting the camera integration time of the thermal infrared imager as the lower limit value I of the integration time1Adjusting the thermal infrared imager to be aligned with the radiation surface of the surface source black body, and ensuring that the radiation surface is full of the view field of the thermal infrared imager;
s32, setting the temperature of the surface source black body as a temperature lower limit point T1Collecting and storing the image output by the thermal infrared imager, and recording the gray level of the image as h1(ii) a Setting the temperature of the surface source black body as an upper temperature limit point T2Collecting and storing the image output by the thermal infrared imager, and recording the gray level of the image as h2；
S33, setting the camera integration time of the thermal infrared imager as the integration time upper limit value I2Setting the temperature of the surface source black body as the ambient temperature Te of the external field, collecting and storing the image output by the thermal infrared imager, and recording the gray level of the image ashe。
Preferably, the step S4 includes the steps of:
s41, calculating the temperatures of the surface source black bodies to be T respectively1、T2And Te, corresponding radiance L1、L2And Le, the relation between the radiant brightness L and the temperature T of the surface source black body is as follows:
wherein λ is the wavelength, λ1And λ2Respectively the lower limit and the upper limit, C, of the wavelength of the response waveband of the thermal infrared imager1Is a first radiation constant, C2The radiation constant is a second radiation constant, L is the radiation brightness of the surface source black body, T is the absolute temperature (unit K) of the surface source black body, and epsilon is the black body emissivity of the surface source black body;
s42, respectively setting the radiation brightness of the surface source black bodies as L1、L2Gray level h of image corresponding to Le time1、h2And he, substituting a calibration formula h as I x (G multiplied by L + O) + b, solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager, wherein the relation is as follows:
preferably, the edge of the area source black body is provided with a windshield for reducing interference.
The invention also provides a thermal infrared imager external field calibration device, which comprises:
a time determining module for determining the lower limit value I of the integration time used for collecting the calibration data according to the ambient temperature Te of the external field1And an upper limit value I of integration time2；
A temperature determination module for determining a lower temperature limit point T used for collecting calibration data according to the ambient temperature Te of the external field1And upper temperature limit point T2；
An image acquisition module for setting the camera integration time of the thermal infrared imager as the lower limit value I of the integration time1Respectively collecting and storing the lower temperature limit point T of the thermal infrared imager1And upper temperature limit point T2Corresponding output image, and changing the integration time of the camera to the upper limit value I of the integration time2Collecting and storing an image correspondingly output by the thermal infrared imager at the ambient temperature Te;
the parameter calculation module is used for solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager according to the gray level of the stored image;
the curve output module is used for obtaining a calibration curve according to a calibration formula h which covers the integral time variable, wherein the calibration formula h is I x (G x L + O) + b, outputting the calibration curve and completing calibration; wherein h is the gray scale of the image output by the thermal infrared imager, I is the camera integration time, and L is the radiance.
The invention also provides computer equipment which comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to realize the first step of the thermal infrared imager external field calibration method.
The invention also provides a computer readable storage medium, on which a computer program is stored, which, when executed by a processor, implements the steps of the first thermal infrared imager external field calibration method described above.
(III) advantageous effects
The technical scheme of the invention has the following advantages: the invention provides a thermal infrared imager external field calibration method and device, computer equipment and a computer readable storage medium.
Drawings
FIG. 1 is a schematic diagram illustrating steps of a thermal infrared imager external field calibration method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of external field calibration of a thermal infrared imager in an embodiment of the invention;
fig. 3 is a schematic structural diagram of an external field calibration apparatus of a thermal infrared imager in an embodiment of the present invention.
In the figure: 1: a thermal infrared imager; 2: a surface source black body; 21: a radiating surface; 22: a windshield; 100: a time determination module; 200: a temperature determination module; 300: an image acquisition module; 400: a parameter calculation module; 500: and a curve output module.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1 and fig. 2, an infrared thermal imager external field calibration method provided by an embodiment of the present invention includes the following steps:
s1, determining the lower limit value I of the integration time used for collecting the calibration data according to the environment temperature Te of the external field1And an upper limit value I of integration time2。
The thermal infrared imager 1 is calibrated according to the external field environment for measuring the target infrared radiation image, and the measurement precision of the thermal infrared imager 1 can be improved.
S2, determining a temperature lower limit point T used for collecting calibration data according to the ambient temperature Te of the external field1And upper temperature limit point T2。
Set lower temperature limit point T1(i.e., the low temperature point to be collected) and the upper temperature limit point T2(i.e. to adoptIntegrated high temperature point) should cover the temperature fluctuation range that may occur in the external field, and preferably, in step S2, the lower limit point T of the temperature used for collecting the calibration data is determined1And upper temperature limit point T2When, T1＝Te-20℃，T2Te +20 ℃. The difference between the low temperature point/high temperature point and the ambient temperature is 20 ℃, the 20 ℃ temperature can ensure that the thermal infrared imager response heat is in a linear region (an optimal working region), and meanwhile, the correction is applicable to a larger temperature range, the thermal infrared imager is likely to be saturated due to too high difference between the low temperature point/high temperature point and the ambient temperature, and the correction application range is reduced due to too low difference.
S3, setting the camera integration time of the thermal infrared imager 1 as the lower limit value I of the integration time1Respectively collecting and storing the lower temperature limit point T of the thermal infrared imager 11And upper temperature limit point T2Changing the integration time of the camera to an upper limit value I of the integration time corresponding to the output image2And acquiring and storing the image correspondingly output by the thermal infrared imager 1 at the ambient temperature Te.
The thermal infrared imager 1 acquires a corresponding image under a set camera integration time to obtain the gray level of the image, and the gray level is expressed by a matrix h, and the elements of the matrix h are the gray level values of each pixel point in the acquired image.
And S4, solving the response rate G of the thermal infrared imager 1, the offset O caused by stray radiation and the offset b caused by dark current of the thermal infrared imager 1 according to the gray levels of the three images stored in the step S3.
S5, obtaining a calibration curve according to a calibration formula h ═ I × (G × L + O) + b covering the integral time variable, outputting the calibration curve, and completing calibration; wherein h is the gray scale of the image output by the thermal infrared imager 1, I is the camera integration time, and L is the radiance of the target measured by the thermal infrared imager 1.
The obtained calibration curve is divided by the lower limit value I of the integration time1To an upper limit value I of the integration time2The temperature range of the applicable measurement target is the lower limit point T of the temperature1To the upper temperature limit point T2。
The invention provides a thermal infrared imager external field calibration method, which is characterized in that calibration parameters (the response rate G of the thermal infrared imager 1, the offset O caused by stray radiation and the offset b caused by dark current of the thermal infrared imager 1) are calculated by collecting three image data of different temperatures under two integration times, so that a calibration curve is obtained, and the rapid calibration of any integration time in a certain range under the external field condition is completed. Compared with the method for acquiring radiometric calibration data under all required integration time during radiometric calibration, the method can effectively reduce operation and save time and labor.
Preferably, the thermal infrared imager external field calibration method adopts the surface source
black body2 to provide the lower temperature limit point T1Upper limit of temperature T2And infrared radiation corresponding to the ambient temperature Te. As shown in fig. 2, the surface source
black body2 is arranged in front of the thermal infrared imager 1, and the
radiation surface21 of the surface source
black body2 is used as a target with infrared radiation for radiation calibration, which is measured by the thermal infrared imager 1. Further, a
windshield22 is further arranged at the edge of the surface source
black body2, and a camera lens of the thermal infrared imager 1 is arranged in a shielding range of the
windshield22 so as to reduce the interference of the external field environment.
Preferably, the step S1 further includes the steps of:
s11 turns on the surface source
black body2, and sets the temperature of the surface source
black body2 to the ambient temperature Te of the external field at that time.
S12, starting the thermal infrared imager 1 to measure infrared radiation, adjusting the thermal infrared imager 1 to be aligned to the
radiation surface21 of the surface source
black body2, and ensuring that the
radiation surface21 is full of the field of view of the thermal infrared imager 1.
S13, checking the median hm of the gray scale of the image corresponding to the planar source
black body2 at this time, adjusting the camera integration time so that hm is hmax/2, hmax is the maximum value of the gray scale that can be output by the thermal infrared imager 1 (for example, hmax of the thermal infrared imager that outputs 14bit is 16383), and recording the integration time Im at this time.
S14, determining the lower limit value I of the integration time used for collecting the calibration data1And an upper limit value I of integration time2，I1＝0.5×Im，I2＝1.5×Im。
The lower limit value I of the integration time is set in this way1And an upper limit value I of integration time2The response of the thermal infrared imager can be ensured to be in a linear region, and if the response is in a lower limit value I of the integration time1And an upper limit value I of integration time2If the difference between the sampling time and Im is too large, the data is easy to be invalid due to the saturation condition, and if the difference is too small, the adjustable range of the integration time is compressed.
Preferably, the step S3 further includes the steps of:
s31, starting the thermal infrared imager 1, stably operating the thermal infrared imager 1 in an external field environment for more than 30 minutes, and setting the camera integration time of the thermal infrared imager 1 as the lower limit value I of the integration time1And adjusting the thermal infrared imager 1 to be aligned with the
radiation surface21 of the surface source
black body2, and ensuring that the
radiation surface21 is full of the field of view of the thermal infrared imager 1.
S32, setting the temperature of the surface source
black body2 as a lower temperature limit point T1Collecting and storing the image output by the thermal infrared imager 1, and correspondingly recording the gray level of the obtained image as h1(ii) a Setting the temperature of the surface source
black body2 as the upper temperature limit point T2Collecting and storing the image output by the thermal infrared imager 1, and correspondingly recording the gray level of the obtained image as h2。
S33, setting the camera integration time of the thermal infrared imager 1 as the integration time upper limit value I2Setting the temperature of the surface source
black body2 as the ambient temperature Te of the external field, collecting and storing the image output by the thermal infrared imager 1, and correspondingly recording the gray level of the image as he.
Preferably, the step S4 further includes the steps of:
s41, calculating the temperature T of the surface source
black body21、T2And Te, corresponding radiance L1、L2And Le, the relationship between the radiant brightness L and the temperature T of the planar source
black body2 is as follows:
wherein λ is the wavelength (μm), λ1And λ2Lower and upper limits, C, respectively, of the wavelength of the response band of the thermal infrared imager 11Is a first radiation constant, C1＝3.7415×104(W·cm-2·μm4)，C2Is a second radiation constant, C2When the above formula is applied, the unit of the temperature of the planar source
black body2 needs to be changed from "c" to "K", where "L" is 1.4388 × 104(μm · K), and "T" is the absolute temperature of the planar source
black body2, and "K" is K, i.e., T "10 ℃" 10+273 ═ 283K, and ∈ "is the black body emissivity of the planar source
black body2.
S42, respectively setting the radiance of the planar source
black body2 as L1、L2Gray level h of image corresponding to Le time1、h2And he, substituting a calibration formula h (I x (G multiplied by L + O) + b), solving the response rate G of the thermal infrared imager 1, the offset O caused by stray radiation and the offset b caused by dark current of the thermal infrared imager 1, wherein the solved relational expression is as follows:
wherein h is1、h2Integration time for camera I1The gray scale of the image collected and stored by the thermal infrared imager 1 is he integral time of the camera is I2The gray scale of the image collected and stored by the thermal infrared imager 1.
As shown in fig. 3, the present invention further provides a thermal infrared imager external field calibration apparatus, which includes a
time determination module100, a
temperature determination module200, an
image acquisition module300, a
parameter calculation module400, and a
curve output module500, wherein:
the
time determination module100 is used for determining the lower limit value I of the integration time used for collecting the calibration data according to the ambient temperature Te of the external field1And an upper limit value I of integration time2。
Further, the
time determination module100 is configured to:
starting the surface source
black body2, and setting the temperature of the surface source
black body2 as the ambient temperature Te of the external field at the moment;
starting the thermal infrared imager 1 to measure infrared radiation, adjusting the thermal infrared imager 1 to be aligned to the
radiation surface21 of the surface source
black body2, and ensuring that the
radiation surface21 is full of the field of view of the thermal infrared imager 1;
checking the gray median hm of the image corresponding to the planar source
black body2 at the moment, adjusting the camera integration time to make hm equal to hmax/2, wherein hmax is the maximum value of gray scales which can be output by the thermal infrared imager 1 (for example, hmax of the thermal infrared imager which outputs 14bit is 16383), and recording the integration time Im at the moment;
determining lower limit value I of integration time used for collecting calibration data1And an upper limit value I of integration time2，I1＝0.5×Im，I2＝1.5×Im。
The
temperature determination module200 is configured to determine a lower temperature limit point T used for collecting calibration data according to the ambient temperature Te of the external field1And upper temperature limit point T2. Further, T1＝Te-20℃，T2＝Te+20℃。
The
image acquisition module300 is used for setting the camera integration time of the thermal infrared imager 1 as the integration time lower limit value I1Respectively collecting and storing the lower temperature limit point T of the thermal infrared imager 11And upper temperature limit point T2Corresponding output image, and changing the integration time of the camera to the upper limit value I of the integration time2And acquiring and storing the image correspondingly output by the thermal infrared imager 1 at the ambient temperature Te.
Further, the
image acquisition module300 is configured to:
starting the thermal infrared imager 1, stably operating the thermal infrared imager 1 in an external field environment for more than 30 minutes, and setting the camera integration time of the thermal infrared imager 1 as the lower limit value I of the integration time1Adjusting the thermal infrared imager 1 to be aligned with the
radiation surface21 of the surface source
black body2, and ensuring that the
radiation surface21 is full of the field of view of the thermal infrared imager 1;
setting the temperature of the surface source
black body2 as a temperature lower limit point T1Collecting and storing the image output by the thermal infrared imager 1, and correspondingly recording the gray level of the obtained image as h1(ii) a Setting the temperature of the surface source
black body2 as the upper temperature limit point T2Collecting and storing the image output by the thermal infrared imager 1, and correspondingly recording the gray level of the obtained image as h2；
Setting the camera integration time of the thermal infrared imager 1 as an integration time upper limit value I2Setting the temperature of the surface source
black body2 as the ambient temperature Te of the external field, collecting and storing redThe image output by the external thermal imager 1 is correspondingly recorded as he in gray scale.
The
parameter calculation module400 is configured to solve the response rate G of the thermal infrared imager 1, the offset O caused by stray radiation, and the offset b caused by dark current of the thermal infrared imager 1 according to the gray levels of the three images stored by the
image acquisition module300.
Further, the
parameter calculation module400 is configured to:
calculating the temperatures of the surface source
black bodies2 to be T respectively1、T2And Te, corresponding radiance L1、L2And Le, the relationship between the radiant brightness L and the temperature T of the planar source
black body2 is as follows:
wherein λ is the wavelength (μm), λ1And λ2Lower and upper limits, C, respectively, of the wavelength of the response band of the thermal infrared imager 11Is a first radiation constant, C1＝3.7415×104(W·cm-2·μm4)，C2Is a second radiation constant, C2When the above formula is applied, the unit of the temperature of the plane source
black body2 needs to be changed from "c" to "K", where T is 1.4388 × 104(μm · K), L is the radiance of the plane source
black body2, T is the absolute temperature of the plane source
black body2, and K is the unit, i.e., T is 10 ℃ ═ 10+273 ═ 283K, and ∈isthe black body emissivity of the plane source
black body2;
the radiation brightness according to the surface source
black body2 is L1、L2Gray level h of image corresponding to Le time1、h2And he, substituting a calibration formula h (I x (G multiplied by L + O) + b), solving the response rate G of the thermal infrared imager 1, the offset O caused by stray radiation and the offset b caused by dark current of the thermal infrared imager 1, wherein the solved relational expression is as follows:
wherein h is1、h2Integration time for camera I1The gray scale of the image collected and stored by the thermal infrared imager 1 is he integral time of the camera is I2The gray scale of the image collected and stored by the thermal infrared imager 1.
The
curve output module500 is configured to obtain a calibration curve according to a calibration formula h ═ I × (G × L + O) + b covering the integration time variable, and output the calibration curve to complete calibration; wherein h is the gray scale of the image output by the thermal infrared imager 1, I is the camera integration time, and L is the radiance.
Particularly, in some preferred embodiments of the present invention, there is further provided a computer device, including a memory and a processor, where the memory stores a computer program, and the processor implements the steps of the method for calibrating an external field of a thermal infrared imager in the above embodiments when executing the computer program.
In other preferred embodiments of the present invention, a computer-readable storage medium is further provided, on which a computer program is stored, and the computer program, when being executed by a processor, implements the steps of the method for calibrating an external field of a thermal infrared imager described in the above embodiments.
It will be understood by those skilled in the art that all or part of the processes of the method according to the above embodiments may be implemented by a computer program, which may be stored in a non-volatile computer-readable storage medium, and when executed, the computer program may include the processes of the above embodiments of the method for calibrating an external field of a thermal infrared imager, and will not be described again here.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A thermal infrared imager external field calibration method is characterized by comprising the following steps:
s1, determining the lower limit value I of the integration time used for collecting the calibration data according to the environment temperature Te of the external field1And an upper limit value I of integration time2；
S2, determining a temperature lower limit point T used for collecting calibration data according to the ambient temperature Te of the external field1And upper temperature limit point T2；
S3, setting the camera integration time of the thermal infrared imager as the integration time lower limit value I1Respectively collecting and storing the lower temperature limit point T of the thermal infrared imager1And upper temperature limit point T2Changing the integration time of the camera to an upper limit value I of the integration time corresponding to the output image2Collecting and storing an image correspondingly output by the thermal infrared imager at the ambient temperature Te;
s4, solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager according to the gray level of the stored image;
s5, obtaining a calibration curve according to a calibration formula h ═ I × (G × L + O) + b covering the integral time variable, outputting the calibration curve, and completing calibration; h is the gray scale of an image output by the thermal infrared imager, I is the integration time of the camera, and L is the radiance;
wherein the step S1 includes the following steps:
s11, starting a surface source black body, and setting the temperature of the surface source black body as the ambient temperature Te of the external field at the moment;
s12, starting the thermal infrared imager for measurement, adjusting the thermal infrared imager to be aligned to the radiation surface of the surface source black body, and ensuring that the radiation surface is full of the field of view of the thermal infrared imager;
s13, checking the gray median hm of the image corresponding to the surface source black body at the moment, adjusting the camera integration time to enable hm to be hmax/2, wherein hmax is the maximum value of the gray scale which can be output by the thermal infrared imager, and recording the integration time Im at the moment;
s14, determining the lower limit value I of the integration time used for collecting the calibration data1And an upper limit value I of integration time2，I1＝0.5×Im，I2＝1.5×Im；
The step S4 includes the following steps:
s41, calculating the temperatures of the surface source black bodies to be T respectively1、T2And Te, corresponding radiance L1、L2And Le, the relation between the radiant brightness L and the temperature T of the surface source black body is as follows:
wherein λ is the wavelength, λ1And λ2Respectively the lower limit and the upper limit, C, of the wavelength of the response waveband of the thermal infrared imager1Is a first radiation constant, C2The radiation constant is a second radiation constant, L is the radiation brightness of the surface source black body, T is the absolute temperature of the surface source black body, and epsilon is the black body emissivity of the surface source black body;
s42, respectively setting the radiation brightness of the surface source black bodies as L1、L2Gray level h of image corresponding to Le time1、h2And he, substituting a calibration formula h as I x (G multiplied by L + O) + b, solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager, wherein the relation is as follows:
2. the thermal infrared imager external field calibration method according to claim 1, characterized in that: providing a lower temperature limit point T by adopting a surface source black body1Upper limit of temperature T2And infrared radiation corresponding to ambient temperature Te.
3. The thermal infrared imager external field calibration method according to claim 1, characterized in that: in step S2, a lower temperature limit T used for collecting calibration data is determined1And upper temperature limit point T2When, T1＝Te-20℃，T2＝Te+20℃。
4. The thermal infrared imager external field calibration method according to claim 2, wherein the step S3 includes the steps of:
s31, starting the thermal infrared imager, stably operating the thermal infrared imager in an external field environment for more than 30 minutes, and setting the camera integration time of the thermal infrared imager as the lower limit value I of the integration time1Adjusting the thermal infrared imager to be aligned with the radiation surface of the surface source black body, and ensuring that the radiation surface is full of the view field of the thermal infrared imager;
s32, setting the temperature of the surface source black body as a temperature lower limit point T1Collecting and storing the image output by the thermal infrared imager, and recording the gray level of the image as h1(ii) a Setting the temperature of the surface source black body as an upper temperature limit point T2Collecting and storing the image output by the thermal infrared imager, and recording the gray level of the image as h2；
S33, setting the camera integration time of the thermal infrared imager as the integration time upper limit value I2Setting the temperature of the surface source black body as the ambient temperature Te of the external field, and collecting and storing the image output by the thermal infrared imager, wherein the gray level of the image is recorded as he.
5. The thermal infrared imager external field calibration method according to claim 2, characterized in that: and a wind shield is arranged at the edge of the area source black body and used for reducing interference.
6. The utility model provides a thermal infrared imager external field calibration device which characterized in that includes:
a time determining module for determining the lower limit value I of the integration time used for collecting the calibration data according to the ambient temperature Te of the external field1And an upper limit value I of integration time2；
A temperature determination module for determining a lower temperature limit point T used for collecting calibration data according to the ambient temperature Te of the external field1And upper temperature limit point T2；
An image acquisition module for setting the camera integration time of the thermal infrared imager as the integration timeLower limit value I1Respectively collecting and storing the lower temperature limit point T of the thermal infrared imager1And upper temperature limit point T2Corresponding output image, and changing the integration time of the camera to the upper limit value I of the integration time2Collecting and storing an image correspondingly output by the thermal infrared imager at the ambient temperature Te;
the parameter calculation module is used for solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager according to the gray level of the stored image;
the curve output module is used for obtaining a calibration curve according to a calibration formula h which covers the integral time variable, wherein the calibration formula h is I x (G x L + O) + b, outputting the calibration curve and completing calibration; h is the gray scale of an image output by the thermal infrared imager, I is the integration time of the camera, and L is the radiance;
wherein the time determination module is configured to:
starting a surface source black body, and setting the temperature of the surface source black body as the ambient temperature Te of the external field at the moment;
starting the thermal infrared imager to measure infrared radiation, adjusting the thermal infrared imager to be aligned to the radiation surface of the surface source black body, and ensuring that the radiation surface is full of the field of view of the thermal infrared imager;
checking the gray median hm of the image corresponding to the surface source black body at the moment, adjusting the integration time of the camera to enable hm to be hmax/2, wherein hmax is the maximum value of the gray scale which can be output by the thermal infrared imager, and recording the integration time Im at the moment;
determining lower limit value I of integration time used for collecting calibration data1And an upper limit value I of integration time2，I1＝0.5×Im，I2＝1.5×Im；
The parameter calculation module is used for:
calculating the temperatures of the surface source black bodies to be T respectively1、T2And Te, corresponding radiance L1、L2And Le, the relation between the radiant brightness L and the temperature T of the surface source black body is as follows:
wherein λ is the wavelength, λ1And λ2Respectively the lower limit and the upper limit, C, of the wavelength of the response waveband of the thermal infrared imager1Is a first radiation constant, C2The radiation constant is a second radiation constant, L is the radiation brightness of the surface source black body, T is the absolute temperature of the surface source black body, and epsilon is the black body emissivity of the surface source black body;
respectively has L radiant brightness according to the surface source black body1、L2Gray level h of image corresponding to Le time1、h2And he, substituting a calibration formula h as I x (G multiplied by L + O) + b, solving the response rate G of the thermal infrared imager, the offset O caused by stray radiation and the offset b caused by the dark current of the thermal infrared imager, wherein the relation is as follows:
7. a computer device comprising a memory and a processor, the memory storing a computer program, wherein the processor when executing the computer program performs the steps of the thermal infrared imager outfield calibration method of claim 1.
8. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method for external field calibration of a thermal infrared imager of claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010511198.5A CN111609937B (en) | 2020-06-08 | 2020-06-08 | Thermal infrared imager external field calibration method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010511198.5A CN111609937B (en) | 2020-06-08 | 2020-06-08 | Thermal infrared imager external field calibration method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111609937A CN111609937A (en) | 2020-09-01 |
| CN111609937B true CN111609937B (en) | 2021-07-20 |
Family
ID=72198540
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010511198.5A Active CN111609937B (en) | 2020-06-08 | 2020-06-08 | Thermal infrared imager external field calibration method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111609937B (en) |
Families Citing this family (2)
* Cited by examiner, † Cited by third party| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112556856B (en) * | 2020-11-16 | 2022-04-05 | 烟台艾睿光电科技有限公司 | Infrared temperature measurement correction method and device and electronic equipment |
| CN112964364B (en) * | 2021-02-04 | 2021-09-03 | 中国人民解放军91977部队 | Portable calibration device and calibration method for thermal infrared imager |
Citations (13)
* Cited by examiner, † Cited by third party| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101620008A (en) * | 2009-07-31 | 2010-01-06 | 北京航空航天大学 | Portable type ground high-spectrum imaging spectrograph suitable for open-air remote sensing |
| CN104406697A (en) * | 2014-11-24 | 2015-03-11 | 浙江大立科技股份有限公司 | Infrared focal plane array rectifying method |
| CN105138720A (en) * | 2015-07-13 | 2015-12-09 | 北京环境特性研究所 | Matrix orthogonal triangularization based rating data curve fitting method |
| CN105241554A (en) * | 2015-09-29 | 2016-01-13 | 北京环境特性研究所 | Non-point source blackbody type radiation source under outfield condition and calibration method thereof |
| CN106706132A (en) * | 2016-12-05 | 2017-05-24 | 中国科学院云南天文台 | Infrared detecting device and method for target recognition in sea surface sun bright band |
| CN107677375A (en) * | 2017-09-21 | 2018-02-09 | 中国科学院长春光学精密机械与物理研究所 | Calibration device and calibration method for infrared radiation measurement system |
| CN108254084A (en) * | 2018-01-18 | 2018-07-06 | 武汉格物优信科技有限公司 | Scaling method and calibration system in a kind of thermal infrared imager production |
| CN108871588A (en) * | 2018-08-09 | 2018-11-23 | 昆明物理研究所 | A kind of infrared imaging system various dimensions joint asymmetric correction method |
| CN109870239A (en) * | 2019-03-12 | 2019-06-11 | 北京环境特性研究所 | The adaptive calibrating method of non-refrigerated infrared focal plane probe |
| CN110231090A (en) * | 2019-03-11 | 2019-09-13 | 中国科学院上海技术物理研究所 | A kind of test method of thermal infrared spectrum instrument internal stray radiation |
| CN110470406A (en) * | 2019-07-10 | 2019-11-19 | 中国科学院上海技术物理研究所 | A kind of measurement method of thermal infrared spectrum instrument stray radiation |
| CN110726475A (en) * | 2019-10-12 | 2020-01-24 | 浙江大华技术股份有限公司 | Infrared temperature measurement calibration method and device, infrared thermal imaging equipment and storage device |
| CN111076821A (en) * | 2019-12-11 | 2020-04-28 | 中国航空工业集团公司洛阳电光设备研究所 | Infrared image non-uniform correction method with integration time self-adaptive switching |
Family Cites Families (2)
* Cited by examiner, † Cited by third party| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102008005167A1 (en) * | 2008-01-19 | 2009-07-23 | Testo Ag | Thermal camera |
| US20180038735A1 (en) * | 2016-08-04 | 2018-02-08 | National Chung Shan Institute Of Science And Technology | Method of detecting temperature change with infrared and method of detecting moving vehicle with infrared |
-
2020
- 2020-06-08 CN CN202010511198.5A patent/CN111609937B/en active Active
Patent Citations (13)
* Cited by examiner, † Cited by third party| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101620008A (en) * | 2009-07-31 | 2010-01-06 | 北京航空航天大学 | Portable type ground high-spectrum imaging spectrograph suitable for open-air remote sensing |
| CN104406697A (en) * | 2014-11-24 | 2015-03-11 | 浙江大立科技股份有限公司 | Infrared focal plane array rectifying method |
| CN105138720A (en) * | 2015-07-13 | 2015-12-09 | 北京环境特性研究所 | Matrix orthogonal triangularization based rating data curve fitting method |
| CN105241554A (en) * | 2015-09-29 | 2016-01-13 | 北京环境特性研究所 | Non-point source blackbody type radiation source under outfield condition and calibration method thereof |
| CN106706132A (en) * | 2016-12-05 | 2017-05-24 | 中国科学院云南天文台 | Infrared detecting device and method for target recognition in sea surface sun bright band |
| CN107677375A (en) * | 2017-09-21 | 2018-02-09 | 中国科学院长春光学精密机械与物理研究所 | Calibration device and calibration method for infrared radiation measurement system |
| CN108254084A (en) * | 2018-01-18 | 2018-07-06 | 武汉格物优信科技有限公司 | Scaling method and calibration system in a kind of thermal infrared imager production |
| CN108871588A (en) * | 2018-08-09 | 2018-11-23 | 昆明物理研究所 | A kind of infrared imaging system various dimensions joint asymmetric correction method |
| CN110231090A (en) * | 2019-03-11 | 2019-09-13 | 中国科学院上海技术物理研究所 | A kind of test method of thermal infrared spectrum instrument internal stray radiation |
| CN109870239A (en) * | 2019-03-12 | 2019-06-11 | 北京环境特性研究所 | The adaptive calibrating method of non-refrigerated infrared focal plane probe |
| CN110470406A (en) * | 2019-07-10 | 2019-11-19 | 中国科学院上海技术物理研究所 | A kind of measurement method of thermal infrared spectrum instrument stray radiation |
| CN110726475A (en) * | 2019-10-12 | 2020-01-24 | 浙江大华技术股份有限公司 | Infrared temperature measurement calibration method and device, infrared thermal imaging equipment and storage device |
| CN111076821A (en) * | 2019-12-11 | 2020-04-28 | 中国航空工业集团公司洛阳电光设备研究所 | Infrared image non-uniform correction method with integration time self-adaptive switching |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111609937A (en) | 2020-09-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI600324B (en) | 2017-09-21 | Infrared Focal Plane Array Module Performance Parameters Measurement Method and Detection of Dead pixels |
| US10598550B2 (en) | 2020-03-24 | Radiometric correction and alignment techniques for thermal imager with non-contact temperature sensor |
| US7928395B2 (en) | 2011-04-19 | Infra-red (IR) sensor with controllable sensitivity |
| US9332197B2 (en) | 2016-05-03 | Infrared sensor control architecture |
| CN109655162A (en) | 2019-04-19 | Thermal infrared imager temperature measurement correction system and method |
| CN104580894B (en) | 2017-10-31 | The multi-point correcting method and system of a kind of infrared focus plane |
| CN109974854B (en) | 2020-11-20 | A radiometric correction method for framed FPI hyperspectral images |
| CN111609937B (en) | 2021-07-20 | Thermal infrared imager external field calibration method and device |
| Zhang et al. | 2015 | A method for improving temperature measurement precision on the uncooled infrared thermal imager |
| US20220187131A1 (en) | 2022-06-16 | Method and system of two-point correction based on temperature substitution |
| CN111044153A (en) | 2020-04-21 | A nonlinear calibration method and device for infrared spectrum of a spectrum correlation system |
| Kusnierek et al. | 2014 | Challenges in using an analog uncooled microbolometer thermal camera to measure crop temperature |
| US8481918B2 (en) | 2013-07-09 | System and method for improving the quality of thermal images |
| US20230046320A1 (en) | 2023-02-16 | Non-uniformity correction calibrations in infrared imaging systems and methods |
| WO2021245772A1 (en) | 2021-12-09 | Infrared imaging device |
| CN107436195A (en) | 2017-12-05 | A kind of passive infrared Migratory Bird Monitoring equipment |
| CN113096041B (en) | 2023-03-24 | Image correction method and device |
| US20190208147A1 (en) | 2019-07-04 | Image output adjustment responsive to integration time changes for infrared imaging devices |
| CN118794547A (en) | 2024-10-18 | A method for measuring target infrared radiation brightness considering ambient temperature correction |
| CN107067433A (en) | 2017-08-18 | A kind of leaf area index ground survey method based on digital image processing techniques |
| US20220187136A1 (en) | 2022-06-16 | Infrared imaging-related uncertainty gauging systems and methods |
| CN111595458B (en) | 2021-04-30 | Thermal infrared imager radiometric calibration method and device |
| CN114993999A (en) | 2022-09-02 | System and method for measuring average transmittance of infrared lens spectrum |
| CN115222619A (en) | 2022-10-21 | Wall surface emissivity solving method based on thermal infrared image correction brightness of thermal imager |
| Zhou et al. | 2023 | A shutter-less nonuniformity correction algorithm based on noise response model for TEC-less uncooled infrared sensors |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 2020-09-01 | PB01 | Publication | |
| 2020-09-01 | PB01 | Publication | |
| 2020-09-25 | SE01 | Entry into force of request for substantive examination | |
| 2020-09-25 | SE01 | Entry into force of request for substantive examination | |
| 2021-07-20 | GR01 | Patent grant | |
| 2021-07-20 | GR01 | Patent grant |