CN113375810A - Thermal infrared imager working temperature measuring device and method for adaptively compensating focal plane - Google Patents
Thermal infrared imager working temperature measuring device and method for adaptively compensating focal plane Download PDFInfo
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Abstract
The invention relates to a thermal infrared imager working temperature measuring device and a method for self-adaptively compensating a focal plane. The method for self-adaptive compensation of the focal plane is based on real-time digital temperature information provided by a temperature measurement part, three-order fitting correction coefficients in all temperature intervals are stored after testing, and the temperature self-adaptive compensation focal plane function module is used for self-adaptively optimizing and correcting the position of the infrared optical imaging focusing focal plane changing along with the temperature. The infrared optical imaging focusing focal plane position changing along with the temperature is adaptively optimized and adjusted based on the measured temperature value, the problems that the imaging focusing is not clear enough, is fuzzy and even can not image are solved, and the clear focusing imaging performance of the thermal infrared imager is improved.
Description
Technical Field
The invention belongs to the technical field of thermal infrared imager measurement, and relates to a thermal infrared imager working temperature measuring device and a method for adaptively compensating a focal plane.
Background
At present, in the field of application of thermal infrared imagers, the thermal infrared imagers are required to be capable of adapting to various severe environmental conditions, and particularly in the field of application of military thermal infrared imagers, the functional performance of the thermal infrared imagers is required to meet the requirements of weapon fire control platform systems in various actual working environments, particularly extreme temperature environments, so that the remote and accurate fighting capability of the fire control systems is improved.
For a large-scale complex weapon system platform, the weapon system platform needs to work in an extreme temperature severe environment, and various heating sources exist to cause internal temperature rise, and the internal temperature is far higher than the temperature of a working environment. Even in extreme cases, the internal operating temperature of the thermal infrared imager may exceed the allowable temperature range, resulting in the thermal infrared imager failing to operate or being damaged. Meanwhile, due to the influence of factors such as optical, structural and electrical design layout, thermal expansion and contraction characteristics of manufacturing materials, assembly and debugging processes and the like, the focal plane position of infrared optical imaging focusing changes along with the temperature, and the imaging focusing is not clear, fuzzy or even incapable of imaging due to the drastic change of the temperature, so that the imaging function of the thermal infrared imager is abnormal, and the imaging function and performance of the weapon system platform under the severe environment with extreme temperature are seriously influenced.
In the former equipment, a thermocouple is used for measuring temperature based on a thermoelectric effect, and voltage of the thermocouple changing along with the temperature is acquired through signal conditioning and measured, so that the device has the characteristics of wide measurement range, stable performance, simple structure, firmness, durability and the like, but has the defects of low precision and poor noise resistance. On the aspect of low precision, the thermocouple measurement precision can only reach the measurement precision of the reference binding point temperature, generally within 1 ℃ to 2 ℃, except for inherent inaccuracy in the thermocouple due to metal characteristics. In terms of poor noise resistance, electromagnetic wave noise generated by stray electric and magnetic fields may cause a problem of measurement instability when a millivolt-level signal is measured. In addition, the former equipment adopts a mode of simulating voltage measurement values to represent temperature, so that the use of an internal functional module of the thermal infrared imager is inconvenient, and internal working temperature data cannot be sent to an external system for operation and use through communication.
Aiming at the problem that the imaging focusing is not clear enough, fuzzy or even incapable of imaging caused by the change of the focal plane position of the infrared optical imaging focusing along with the temperature, the early stage is mainly guaranteed by means of enhanced design, processing and assembly and adjustment, and the problem that the compensation cannot be compensated or cannot be accurately corrected exists because the compensation is not compensated or is performed in a first-order linear compensation mode after the assembly and adjustment is completed.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method for measuring the internal working temperature of a thermal infrared imager and adaptively compensating a focal plane.
On one hand, the internal working temperature of the thermal infrared imager is rapidly measured with high precision, and the real-time working temperature is provided for the internal temperature self-adaption of the thermal infrared imager and the use of an external system operating user; on the other hand, based on real-time digital temperature information provided by the measuring device, the position of an infrared optical imaging focusing focal plane changing along with the temperature is adaptively optimized and corrected, and the problems that imaging focusing is not clear enough, fuzzy and even incapable of imaging are solved.
The invention relates to a thermal infrared imager working temperature measuring device which mainly comprises a transistor element, an operational amplification conditioning circuit, an analog-to-digital conversion circuit, a digital signal processor (programming to realize the temperature measurement digital signal processing function), external equipment and the like.
The method for realizing the temperature measurement comprises the following steps:
step 1, mounting a transistor element near a focusing lens in a thermal infrared imager, connecting a driving working voltage provided by an analog circuit, and outputting a measurement voltage changing along with temperature by the transistor element; then, after the measurement voltage is conditioned to the measurement range of 0V to 5V according to the formula (1) by using an operational amplifier circuit, the measurement voltage signal of 0V to 5V is converted into a measurement Digital signal of 0V to 66635 according to the formula (2) by using an Analog-to-Digital Converter (ADC);
Vout＝Again×Vin+Boffset…………(1)
Vout-operational amplification conditioning circuit output voltage signal;
Vin-operational amplification conditioning circuit input voltage signal;
Again-operational amplification conditioning circuit gain factor;
Boffset-operational amplification conditioning circuit offset factor.
Vdigital＝Vanalog÷Vmax×Kmax…………(2)
Vdigital-measuring the digital signal;
Vanalog-measuring an analog voltage signal;
Vmax-the maximum input analog voltage of the analog-to-digital conversion circuit;
Kmax-analog-to-digital conversion circuitry converts the numerical coefficients.
and 3, calculating the corresponding temperature in centigrade by the digital signal processor through a relation calculation formula (3) between the temperature and the measured digital signal, and recording and storing the temperature digital information, wherein the display precision of the temperature digital information can reach +/-0.01 ℃. After the temperature digital information is obtained, the temperature digital information is superimposed on an output image of the thermal infrared imager for observation by a user, and meanwhile, internal working temperature data is sent to an external system for operation and use through communication, and is provided for an internal functional module of the thermal infrared imager for use.
Vdigital-measuring the digital signal;
Aemp-a quadratic factor of conversion of the temperature to a measured digital signal;
Bemp-a factor of once conversion of the temperature to the measured digital signal;
Cemp-a temperature to measurement digital signal scaling offset factor;
Temp-temperature values in degrees celsius.
The implementation steps of the temperature self-adaptive focal plane compensation method are as follows:
step 1, a set of calibration test environment is built, a warm box which can provide simulated working environment temperature for a thermal imager and is provided with a warm box observation window is configured, and a collimator tube which is provided with a four-bar target simulation target and is used for testing the image performance of the thermal infrared imager is configured outside the warm box observation window;
ΔYx＝Yx-Y0
in the formula: delta Yx- -deviation of focal plane position, Yx- -focal plane position at target operating environment temperature, Y0-number of focal plane positions at a normal temperature working environment temperature of 20 ℃;
calculating the internal temperature deviation value using the following equation:
ΔTx＝Tx-T0
in the formula: deltaTx- -internal temperature deviation, TxInternal operating temperature at target operating ambient temperature, T0-an internal working temperature of 20 ℃ at ambient working temperature;
and 3, taking the temperature of the normal-temperature working environment at 20 ℃ as a reference, substituting the position deviation value and the temperature deviation value at the interval of 20 ℃ in the upper table into the following formula to calculate a third-order fitting correction coefficient A, B, C, D of each temperature interval of the focal plane:
in the formula: delta Yx- -focal plane position deviation, Δ Tx-internal temperature deviation, a-temperature interval third order fitting correction coefficient, B-temperature interval second order fitting correction coefficient, C-temperature interval first order fitting correction coefficient, D-temperature interval zero order fitting correction coefficient;
in the formula: delta Yx- -focal plane position deviation, Δ Tx-internal temperature deviation, a-temperature interval third order fitting correction coefficient, B-temperature interval second order fitting correction coefficient, C-temperature interval first order fitting correction coefficient, D-temperature interval zero order fitting correction coefficient;
and 7, calculating the compensated and corrected focal plane position according to the following formula to realize the temperature self-adaptive compensation focal plane:
Yx＝Y0+ΔYx
in the formula: delta Yx- -deviation of focal plane position, Yx- -focal plane position at target operating environment temperature, Y0-number of focal plane positions at a normal temperature working environment temperature of 20 ℃.
The beneficial effects of the invention include:
(1) the invention is easy to realize, the construction cost is low, the temperature measurement refreshing speed reaches millisecond level, the temperature measurement range covers the working temperature of the product, and the temperature measurement precision reaches +/-0.01 ℃.
(2) By adopting the invention, the operating user of the external system can monitor the internal working temperature of the thermal infrared imager in real time through video display.
(3) By adopting the invention, internal working temperature data can be provided for the temperature self-adaptive function as self-adaptive calculation parameters.
(4) The method can be used as a means for evaluating the internal working temperature variation under the condition of the full temperature range of the thermal infrared imager and can be used as an acceptance method for the internal working temperature index of the thermal infrared imager.
(5) By adopting the method and the device, the position of the infrared optical imaging focusing focal plane changing along with the temperature can be adaptively optimized and adjusted based on the measured temperature value, the problems that the imaging focusing is not clear enough, fuzzy and even can not image are solved, and the clear focusing imaging performance of the thermal infrared imager is improved.
Drawings
Fig. 1 is a schematic view of the installation position of a temperature measuring transistor element of the thermal infrared imager working temperature measuring device of the present invention.
FIG. 2 is a schematic diagram of the thermal infrared imager operating temperature measuring device of the present invention.
FIG. 3 is a flow chart of digital signal processing of the thermal infrared imager working temperature measuring device of the present invention.
FIG. 4 is a graph of the operating temperature of the thermal infrared imager video image display.
FIG. 5 is a schematic diagram of a calibration test environment in the method for adaptively compensating the focal plane of the thermal infrared imager according to the present invention.
FIG. 6 is an observation diagram of the thermal infrared imager on a four-bar target simulation test target.
FIG. 7 is a flow chart of a method for adaptively compensating the focal plane for the operating temperature of the thermal infrared imager according to the present invention.
In the figure: 2-a temperature box, 3-a temperature box observation window, 4-a thermal infrared imager, 5-a collimator, 6-a shock absorption support working platform and 7-the ground; 8-transistor element, 9-operational amplification conditioning circuit, 10-analog-digital conversion circuit, 11-DSP digital signal processor, 12-memory module, 13-image display module, 14-serial port communication module and 15-power supply circuit.
Detailed Description
In order to make the objects, contents, and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.
Example 1
As shown in fig. 1, a transistor element for measuring temperature is installed near the position of the focusing lens inside the thermal infrared imager 4, one transistor element 8 may be installed to measure one operating temperature, or a plurality of transistor elements 8 may be installed at different positions where temperature needs to be monitored to measure a plurality of temperatures, and this embodiment takes one measured temperature as an example for description.
As shown in fig. 2, the thermal infrared imager working temperature measuring device of the present invention is composed of a transistor element 8, an operational amplification conditioning circuit 9, an analog-to-digital conversion circuit 10, a DSP digital signal processor 11, a memory module 12, an image display module 13, a serial communication module 14, a power supply circuit 15, and the like.
The transistor element 8, the operational amplification conditioning circuit 9, the analog-to-digital conversion circuit 10 and the DSP digital signal processor 11 are electrically connected in sequence, the DSP digital signal processor 11 is respectively connected with the memory module 12, the image display module 13 and the serial port communication module 14, and the power supply circuit 15 is respectively used for supplying power to the transistor element 8, the operational amplification conditioning circuit 9, the analog-to-digital conversion circuit 10 and the DSP digital signal processor 11.
Firstly, connecting a transistor element 8 for temperature measurement to an analog signal ground plane through a lead cable to obtain a working reference level; then the power supply is connected to a simulation 3.3V power supply circuit through a lead cable to obtain a working power supply; and finally, the output measurement voltage signal is connected to the operational amplification conditioning circuit 9 through a lead cable.
An operational amplifier is adopted to design an operational amplification conditioning circuit 9, an Analog low-pass filter is firstly used for processing signal noise of an input Analog signal, then the input measurement voltage signal is adjusted to be in a measurement range of 0V to 5V according to a formula (1), and then an Analog-to-Digital Converter (Analog-to-Digital Converter) is used for converting the measurement voltage signal of 0V to 5V into a measurement Digital signal of 0V to 66635 according to a formula (2);
Vout＝Again×Vin+Boffset…………(1)
Vout-operational amplification conditioning circuit output voltage signal;
Vin-operational amplification conditioning circuit input voltage signal;
Again-operational amplification conditioning circuit gain factor;
Boffset-operational amplification conditioning circuit offset factor.
Vdigital＝Vanalog÷Vmax×Kmax…………(2)
Vdigital-measuring the digital signal;
Vanalog-measuring an analog voltage signal;
Vmax-the maximum input analog voltage of the analog-to-digital conversion circuit;
Kmax-analog-to-digital conversion circuitry converts the numerical coefficients.
As shown in fig. 3, the DSP digital signal processor 11 receives the measurement digital signal, processes the measurement digital signal, and outputs temperature information for use by various functional peripherals. The DSP 11 acquires input measurement data, firstly enters an abnormal data function module, judges the state of a measurement digital signal and rejects abnormal measurement data; then, entering a noise data processing function module, and using a low-pass filter to remove noise jump of the measured digital signal; then, entering a nonlinear calibration function module, carrying out nonlinear calibration processing on the measurement digital signal, and linearizing the measurement digital signal; then calculating the corresponding temperature in centigrade according to a relation formula (3) between the temperature and the measurement digital signal through a temperature conversion function module, wherein the display precision of the temperature digital information can reach +/-0.01 ℃; and finally, providing the temperature information to various functional peripherals by adopting a temperature information sending functional module, wherein the temperature information sending functional module comprises the following steps: the temperature information is stored in a memory, the temperature digital information is superposed to an output image video, the temperature information is sent to an external system platform through serial port information, the temperature information is provided for the interior of the thermal infrared imager to carry out temperature self-adaptive compensation focal plane use, and parameters of the adjusting device are adapted along with the temperature characteristic change.
Vdigital-measuring the digital signal;
Aemp-a quadratic factor of conversion of the temperature to a measured digital signal;
Bemp-a factor of once conversion of the temperature to the measured digital signal;
Cemp-a temperature to measurement digital signal scaling offset factor;
Temp-temperature values in degrees celsius.
Based on the embodiment, the developed thermal infrared imager is provided with a temperature measuring transistor element 8, a transistor driving module, an operational amplification module and an analog-to-digital conversion module on a hardware circuit, and software with temperature signal receiving, processing and transmitting functions and the like is added in the original digital signal processor, so that the internal working temperature of a certain thermal infrared imager is detected and provided for each functional module.
In the test in this embodiment, the internal working temperature of the thermal infrared imager is measured and the functional performance of each functional module using the internal working temperature is monitored under various test conditions within the typical environmental working temperature range of the thermal infrared imager (-45 ℃ to +65 ℃). The measurement temperature range can also be changed according to the actual requirement of the product for adapting to the environment.
Within the typical environment working temperature range of the thermal infrared imager (-45 ℃ to +65 ℃), the thermal infrared imager is turned on to start working, the internal working temperature can be detected, and the following functions are completed: as shown in fig. 4, the internal working temperature information is superimposed to the video image of the thermal infrared imager for the user to observe through the video; sending a temperature value to the system platform through an interconnected serial port between the thermal infrared imager and the system platform; the thermal infrared imager automatically stores the detected temperature information into an internal memory for a user to record and inquire, sends the temperature information to the inside of the optical sight for temperature self-adaptive use, and adjusts the parameters of the device adapted to the temperature characteristic change.
Example 2
According to the flow chart of the embodiment shown in fig. 7, firstly, a set of calibration test environment shown in fig. 5 is established, an incubator 2 which can provide a simulated working environment temperature and is provided with an incubator observation window 3 is configured, and the assembled thermal infrared imager 4 is placed inside; a collimator 5 is arranged at an incubator observation window 3 outside an incubator 2 and placed on a damping support working platform 6, and a four-rod target simulation test target for testing the image performance of a thermal infrared imager 4 product is arranged on the collimator 5. After the thermal infrared imager 4 is started to work, the position and the lens of the thermal infrared imager 4 are adjusted, the output video image shown in fig. 6 appears on the display through the incubator observation window 3 and faces the external collimator 5, the four-bar target simulation test target observation image is shown for the thermal infrared imager 4, and the four black stripes in the image are four-bar target simulation test target black thermal images arranged on the collimator in a heating state (the thermal infrared imager can be set in a black-hot or white-hot state, the hot target in the black-hot state is black, and the hot target in the white-hot state is white). Through the image effect of the four-bar target image for testing the image performance of the thermal imager product shown in fig. 6, the image definition can be conveniently judged, and a proper focusing focal plane position can be found.
And then, setting the target temperature of the incubator 2 to be 20 ℃ under the condition that the thermal infrared imager 4 is in a shutdown state, simulating the temperature of a normal-temperature working environment, and preserving the heat for 3 hours at 20 ℃. After heat preservation, starting the system to observe a four-bar target simulation test target, focusing to find out the focal plane position of a focusing lens for clear imaging, recording the position as Y0, and simultaneously recording the internal working temperature T0 measured by the thermal infrared imager at the current moment.
And secondly, within a typical environment working temperature range (-45 ℃ to +65 ℃), selecting a proper working environment temperature interval by taking the normal-temperature working environment temperature of 20 ℃ as a reference according to the product characteristics, and listing target temperature values to be tested. And setting the incubator 2 to be the target temperature to be tested when the thermal infrared imager 4 is in a shutdown state, simulating the corresponding working environment temperature, and preserving the heat for 3 hours under the target temperature condition. After heat preservation, starting the thermal imaging system to observe a four-bar target simulation test target, focusing to find and record the focal plane position of a focusing lens for clear imaging, and simultaneously recording the internal working temperature measured by the thermal infrared imager at the current moment.
Taking the normal temperature working environment temperature of 20 ℃ as a reference, taking a typical working environment temperature as an example at an interval of 5 ℃, collecting and recording test data as shown in table 1:
TABLE 1 Coke surface position and internal temperature chart at each target working environment temperature
| Ambient temperature (. degree. C.) | -45 | -40 | -35 | -30 | -25 | -20 | -15 | -10 |
| Focal plane position (μm) | Y1 | Y2 | Y3 | Y4 | Y5 | Y6 | Y7 | Y8 |
| Internal temperature (. degree.C.) | T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 |
| Ambient temperature (. degree. C.) | -5 | 0 | 5 | 10 | 15 | 20 | 25 | 30 |
| Focal plane position (μm) | Y9 | Y10 | Y11 | Y12 | Y0 | Y13 | Y14 | Y15 |
| Internal temperature (. degree.C.) | T9 | T10 | T11 | T12 | T0 | T13 | T14 | T15 |
| Ambient temperature (. degree. C.) | 35 | 40 | 45 | 50 | 55 | 60 | 65 | |
| Focal plane position (μm) | T16 | T17 | T18 | T19 | T20 | T21 | T22 | |
| Internal temperature (. degree.C.) | Y16 | Y17 | Y18 | Y19 | Y20 | Y21 | Y22 |
Next, using the focal plane position Y0 and the internal temperature T0 collected and recorded in the 20 ℃ normal temperature working environment temperature as references, the focal plane position deviation value was calculated by equation (4) and the internal temperature deviation value was calculated by equation (5) using the test data collected in each environment temperature in the above table, and the contents were recorded as shown in table 2.
ΔYx＝Yx-Y0…………(4)
ΔYx-focal plane position deviation;
Yx-the focal plane position at the target working environment temperature;
Y0-number of focal plane positions at a normal temperature working environment temperature of 20 ℃.
ΔTx＝Tx-T0…………(5)
ΔTx-internal temperature deviation;
Tx-an internal working temperature at a target working environment temperature;
T0-an internal working temperature of 20 ℃ at ambient working temperature.
TABLE 2 focal plane position deviation and internal temperature deviation tables at respective target operating environment temperatures
| Ambient temperature (. degree. C.) | -45 | -40 | -35 | -30 | -25 | -20 | -15 | -10 |
| Deviation of focal plane position (mum) | ΔY1 | ΔY2 | ΔY3 | ΔY4 | ΔY5 | ΔY6 | ΔY7 | ΔY8 |
| Internal temperature deviation (. degree. C.) | ΔT1 | ΔT2 | ΔT3 | ΔT4 | ΔT5 | ΔT6 | ΔT7 | ΔT8 |
| Ambient temperature (. degree. C.) | -5 | 0 | 5 | 10 | 15 | 20 | 25 | 30 |
| Deviation of focal plane position (mum) | ΔY9 | ΔY10 | ΔY11 | ΔY12 | Y0 | ΔY13 | ΔY14 | ΔY15 |
| Internal temperature deviation (. degree. C.) | ΔT9 | ΔT10 | ΔT11 | ΔT12 | T0 | ΔT13 | ΔT14 | ΔT15 |
| Ambient temperature (. degree. C.) | 35 | 40 | 45 | 50 | 55 | 60 | 65 | |
| Deviation of focal plane position (mum) | ΔY16 | ΔY17 | ΔY18 | ΔY19 | ΔY20 | ΔY21 | ΔY22 | |
| Internal temperature deviation (. degree. C.) | ΔT16 | ΔT17 | ΔT18 | ΔT19 | ΔT20 | ΔT21 | ΔT22 |
And (3) taking the normal-temperature working environment temperature of 20 ℃ as a reference, substituting the position deviation value and the temperature deviation value at the interval of 20 ℃ in the table into a formula (6) to calculate a three-order fitting correction coefficient A, B, C, D of each temperature interval of the focal plane, and finishing and recording the three-order fitting correction coefficient as shown in the table 3.
ΔYx-focal plane position deviation;
ΔTx-internal temperature deviation;
a-the correction coefficient of third order fitting in the temperature interval;
b-temperature interval second order fitting correction coefficient;
c- -first order fitting correction coefficient of temperature interval;
d-temperature interval zeroth order fitting correction coefficient.
TABLE 3 correction coefficient table of third-order fitting in each temperature interval
And storing the three-order fitting correction coefficients in each temperature interval in the table 3 in a temperature self-adaptive compensation focal plane functional module of an electronic system of the thermal infrared imager in a look-up table mode through programming.
The method for temperature adaptive compensation of the focal plane obtains real-time internal working temperature through the information sent in embodiment 1, calls a stored three-order fitting correction coefficient A, B, C, D according to a temperature interval where a detected internal working temperature value is located, calculates the focal plane offset according to a formula (6), calculates the focal plane position after compensation and correction according to a formula (7), wherein the focal plane position is the real-time digital temperature information provided based on detection, and adaptively optimizes and corrects the focal plane position of infrared optical clear imaging after correction, so that the focal point change of optical imaging focusing caused by the change of optical machine characteristics along with the temperature change is adaptively adjusted based on the measured temperature value, and the problems that the imaging focusing is not clear enough, fuzzy or even incapable of imaging are solved.
Yx＝Y0+ΔYx…………(7)
ΔYx-focal plane position deviation;
Yx-the focal plane position at the target working environment temperature;
Y0-number of focal plane positions at a normal temperature working environment temperature of 20 ℃.
The measuring method comprises the steps of acquiring an analog voltage signal corresponding to the temperature of an installation position in the thermal infrared imager by using a transistor element, carrying out operational amplification conditioning on the voltage signal by using an operational amplification and analog-to-digital conversion module circuit, converting the voltage signal into a measuring digital signal of 0 to 66635, and running a written measuring digital signal processing function program by using a digital signal processor to complete abnormal data processing, noise data processing, nonlinear calibration processing, temperature conversion in centigrade and temperature information sending processing so as to measure and output the internal working temperature of the thermal infrared imager.
The invention stores the three-order fitting correction coefficient of each temperature interval after testing based on the real-time digital temperature information provided by the temperature measurement part, and the temperature self-adaptive compensation focal plane function module adaptively optimizes and corrects the position of the infrared optical imaging focusing focal plane which changes along with the temperature, thereby solving the problems of unclear imaging focusing and even incapability of imaging.
Typically, taking an observing and sighting type thermal infrared imager with a wide view field, a medium view field and a narrow view field as an example, after the thermal infrared imager is adjusted, the positions of the focusing focal planes of the wide view field, the medium view field and the narrow view field which can be clearly imaged are tested and calibrated at the normal temperature of 20 ℃. Working at the high-temperature environment temperature of 65 ℃, compared with the normal-temperature working at 20 ℃, the positions of the focusing focal planes of the wide, middle and narrow fields of clear imaging are changed, the deviations of-2660 mu m, +1830 mu m and-1070 mu m are generated in sequence, the internal temperature is gradually increased under the influence of a heating source along with the lengthening of the starting working time, and the absolute value of the deviation of the focal plane position is gradually increased; when the imaging device works at the low-temperature environment temperature of minus 45 ℃, compared with the normal-temperature work at 20 ℃, the positions of the focusing focal planes of the wide, the middle and the narrow fields of clear imaging are changed, the deviations of +3085 mu m, -2150 mu m and +1215 mu m are sequentially generated, the internal temperature is gradually increased under the influence of a heating source as the working time of the device is prolonged, and the absolute value of the deviation of the focal plane position is gradually reduced. The allowable deviation ranges of the focus focal plane positions of three fields of view with wide, medium and narrow clear imaging ranges of-110 mu m to +110 mu m, -70 mu m to +70 mu m and-30 mu m to +30 mu m are respectively designed by infrared optics. The thermal imager works in the environment with high temperature of 65 ℃ and low temperature of minus 45 ℃, the wide view field, the middle view field and the narrow view field generate position deviation of a focusing focal plane, and the deviation value exceeds the allowable deviation range. If the deviation of an optical imaging focusing focal plane generated by temperature change is not compensated, infrared light radiated by a scene cannot be focused and imaged, so that the imaging function of the thermal infrared imager is abnormal; the invention stores the three-order fitting correction coefficient of each temperature interval after testing based on the real-time digital temperature information provided by the temperature measuring part, the temperature self-adaptive compensation focal plane function module adaptively optimizes and corrects the infrared optical imaging focusing focal plane position changing along with the temperature, and when the temperature self-adaptive compensation focal plane function module works in a typical environment working temperature range (-45 ℃ to +65 ℃), the positions of the wide, medium and narrow three field focusing focal planes of clear imaging are adaptively optimized and corrected to be within the deviation range allowed by the infrared optical design, thereby solving the problem that infrared light radiated by a scene cannot be focused and imaged and realizing infrared light focusing and clear imaging.
The invention relates to a method for evaluating the internal working temperature variation under the condition of a thermal infrared imager in a full-temperature range, in particular to a method for measuring the internal working temperature of the thermal infrared imager in a universal manner, which can be supplemented to standards by revising relevant standards for acceptance of the thermal infrared imager in the future.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (5)
1. The utility model provides a thermal infrared imager operating temperature measuring device which characterized in that:
the measuring device mainly comprises a transistor element, an operational amplification conditioning circuit, an analog-to-digital conversion circuit, a DSP (digital signal processor), a memory module, an image display module, a serial communication module and a power supply circuit; the transistor element is arranged inside the thermal infrared imager;
the transistor element, the operational amplification conditioning circuit, the analog-to-digital conversion circuit and the DSP are electrically connected in sequence, the DSP is respectively connected with the memory module, the image display module and the serial port communication module, and the power supply circuit is respectively used for supplying power to the transistor element, the operational amplification conditioning circuit, the analog-to-digital conversion circuit and the DSP;
the DSP digital signal processor acquires input measurement data, firstly enters an abnormal data function module, judges the state of the measurement digital signal and rejects abnormal measurement data; then, entering a noise data processing function module, and using a low-pass filter to remove noise jump of the measured digital signal; then, entering a nonlinear calibration function module, carrying out nonlinear calibration processing on the measurement digital signal, and linearizing the measurement digital signal; and then through a temperature conversion function module, according to a relation formula from temperature to measurement digital signals:
calculating the corresponding centigrade temperature, wherein: vdigitalMeasurement of digital signals, Aemp-a quadratic coefficient of conversion of the temperature to the measured digital signal, Bemp-a factor of conversion of temperature to measured digital signal, Cemp-conversion of the temperature to a measured digital signal by an offset factor, Temp-a temperature value in degrees celsius;
and finally, providing the temperature information to various functional peripherals by adopting a temperature information sending functional module.
2. The thermal infrared imager operating temperature measuring device of claim 1, characterized in that:
the method provides the temperature information to various functional peripherals, including storing the temperature information in a memory, superposing the temperature digital information to an output image video, sending the temperature information to an external system platform through a serial port message, providing the temperature information to the inside of an optical sighting device for temperature self-adaptive compensation focal plane use and adjusting the adaptive parameters of the device along with the temperature characteristic change.
3. The thermal infrared imager operating temperature measuring device of claim 1 or 2, characterized in that:
the transistor element is positioned inside the thermal infrared imager and close to the focusing lens.
4. A method for adaptively compensating a focal plane by using the working temperature of a thermal infrared imager is characterized by comprising the following steps:
step 1, a set of calibration test environment is built, a warm box which can provide simulated working environment temperature for a thermal imager and is provided with a warm box observation window is configured, and a collimator tube which is provided with a four-bar target simulation target and is used for testing the image performance of the thermal infrared imager is configured outside the warm box observation window;
step 2, taking the focal plane position Y0 and the internal temperature T0 acquired and recorded by the temperature of the normal-temperature working environment of 20 ℃ as references, selecting a proper working environment temperature interval according to the product characteristics, measuring the focal plane position and the internal temperature of the focusing lens which can clearly image at each target working environment temperature, and calculating the focal plane position deviation value by adopting the following formula:
△Yx＝Yx-Y0
in the formula: delta Yx- -deviation of focal plane position, Yx- -focal plane position at target operating environment temperature, Y0-number of focal plane positions at a normal temperature working environment temperature of 20 ℃;
calculating the internal temperature deviation value using the following equation:
△Tx＝Tx-T0
in the formula: delta Tx-internal temperature deviation, TxInternal operating temperature at target operating ambient temperature, T0-an internal working temperature of 20 ℃ at ambient working temperature;
and 3, taking the temperature of the normal-temperature working environment at 20 ℃ as a reference, substituting the position deviation value and the temperature deviation value at the interval of 20 ℃ in the upper table into the following formula to calculate a third-order fitting correction coefficient A, B, C, D of each temperature interval of the focal plane:
in the formula: delta Yx-deviation of focal plane position,. DELTA.Tx-internal temperature deviation, a-temperature interval third order fitting correction coefficient, B-temperature interval second order fitting correction coefficient, C-temperature interval first order fitting correction coefficient, D-temperature interval zero order fitting correction coefficient;
step 4, storing the three-order fitting correction coefficients of each temperature interval in a temperature self-adaptive compensation focal plane functional module of an electronic system of the thermal infrared imager in a lookup table mode through programming for realizing temperature self-adaptive compensation focal plane;
step 5, acquiring the internal working temperature of the thermal infrared imager in real time through a working temperature measuring device;
step 6, according to the temperature interval where the obtained internal working temperature value is located, calling a stored third-order fitting correction coefficient A, B, C, D, and calculating the focal plane position offset according to the following formula:
in the formula: delta Yx-deviation of focal plane position,. DELTA.Tx-internal temperature deviation, a-temperature interval third order fitting correction coefficient, B-temperature interval second order fitting correction coefficient, C-temperature interval first order fitting correction coefficient, D-temperature interval zero order fitting correction coefficient;
and 7, calculating the compensated and corrected focal plane position according to the following formula to realize the temperature self-adaptive compensation focal plane:
Yx＝Y0+△Yx
in the formula: delta Yx- -deviation of focal plane position, Yx- -focal plane position at target operating environment temperature, Y0-number of focal plane positions at a normal temperature working environment temperature of 20 ℃.
5. The method for adaptively compensating the focal plane according to the operating temperature of the thermal infrared imager of claim 4, wherein in step 4:
and storing the three-order fitting correction coefficients of all the temperature intervals in a temperature self-adaptive compensation focal plane functional module of an electronic system of the thermal infrared imager in a table look-up mode through programming for realizing the temperature self-adaptive compensation focal plane.
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