CN115901187A - Device and method for testing thermal stability of optical axis of infrared sighting device - Google Patents
Device and method for testing thermal stability of optical axis of infrared sighting device Download PDFInfo
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Abstract
The invention discloses a device and a method for testing the thermal stability of an optical axis of an infrared sighting device. During testing, the temperature test box provides constant temperature conditions for the infrared sighting device, the tool flange and the second reference reflector in the box; the theodolite measures the variation of an included angle between the first reference reflector and the second reference reflector; meanwhile, the position variation of the center position of the output infrared image relative to the infrared heat radiation target under different temperature conditions is recorded through an infrared sighting device; and calculating and analyzing the position variation corrected by the included angle variation to obtain the thermal drift of the optical axis and evaluate the thermal stability of the optical axis. According to the invention, by judging the change of the included angle, the testing error caused by instability of the angle measuring equipment in the long-time measuring process is eliminated, and the harsh requirement of high-precision measurement on the stability of the testing equipment is reduced.
Description
Technical Field
The invention relates to a device and a method for testing thermal stability of an optical axis of an infrared sight, belonging to the field of thermal stability testing of thermal infrared imagers.
Background
Because the expend with heat and contract with cold nature of material, the optical axis of infrared sight can produce the drift condition for the normal atmospheric temperature when ambient temperature changes, and the drift of optical axis can lead to producing the deviation between the optical axis of infrared sight and the true optical axis, leads to the target performance decline of infrared sight, so the optical axis thermal stability of reinforcing infrared sight, can effectively promote the target accuracy of infrared sight. The method aims at the accurate measurement of the change condition of the optical axis of the infrared sighting device, and is a precondition for recognizing the thermal deformation condition of the optical axis of the infrared sighting device, optimizing the optical system of the infrared sighting device and improving the thermal stability of the optical axis of the infrared sighting device.
An infrared sight generally includes an infrared optical system, an infrared detector assembly, infrared image processing circuitry, and a mechanical support structure. The infrared radiation energy of the target is transmitted to a photosensitive element of the infrared detector assembly through the infrared optical system, the infrared detector assembly converts the received infrared radiation energy into an electric signal for transmission due to a photoelectric conversion effect, and the infrared image processing circuit processes the electric signal and finally outputs an infrared thermal image visible to human eyes. Wherein, infrared optical system, infrared detector subassembly and mechanical bearing structure can direct influence optical axis thermal stability, and infrared image processing circuit is because the heat that the components and parts during operation of circuit produced, and the thermal stability of infrared optical system, infrared detector subassembly and mechanical bearing structure can be influenced to the temperature gradient that this heat arouses to indirect influence optical axis thermal stability. The infrared image is output in a video format, the image of the display consists of pixels, the pixels correspond to the infrared sighting device and are pixels of a core device detector, and the number of the pixels is an expression mode of the specification of the detector. For example, the medium wave is 640 × 512 infrared sighting device, the medium wave is the working band of the detector, 640 × 512 indicates the specification of the detector used, 640 pixels are arranged in the horizontal direction, and 512 pixels are arranged in the vertical direction. Typically one picture element corresponds to one pixel on the image.
The thermal stability of the optical axis of the infrared sight, which is the ability of the infrared sight to resist temperature change of the center position of the infrared image, is usually measured by the offset of the center position of the infrared image in a certain temperature change range relative to the center position of a reference temperature point, and the unit is: a pixel. It can also be measured by the deviation angle of the optical axis in a certain temperature variation range from the initial optical axis at a reference temperature point, and the unit is: angle seconds per degree. A smaller value indicates a higher thermal stability of the infrared sight.
The method for testing the thermal stability of the optical axis of the infrared sighting device generally comprises the steps of adhering a plane reflector to an installation flange of the infrared sighting device, sending a beam of extremely fine light to the plane reflector through a goniometer, receiving the reflected light beam, and obtaining the reflection angle of the plane reflector through the goniometer. At the moment, the temperature test box applies temperature control to the infrared sighting device, the infrared sighting device needs to aim at a fixed infrared heat radiation target all the time before and after the temperature change, and the difference of the reflection angles of the plane reflection mirrors before and after the temperature change is the optical axis heat drift amount of the infrared sighting device and is measured by the offset angle.
However, the traditional measurement method has very high requirements on the anti-interference capability of the goniometer and the infrared thermal radiation target, and needs to ensure that the initial positions of the goniometer and the infrared thermal radiation target are kept fixed under the influence of long-time working vibration of the temperature test box, and under the condition, the difference between the reflection angles before and after the temperature change obtained through testing can accurately represent the optical axis thermal drift condition of the infrared sighting device. However, as long as the initial positions of the goniometer and the infrared thermal radiation target change due to environmental vibration in the testing process, the change amount is directly introduced into the final measurement result and cannot be eliminated, so that a large and random error exists between the measurement result and the real optical axis thermal drift value, and the optical axis thermal stability test and the optimization design of the infrared sighting device are disturbed.
Disclosure of Invention
The invention aims to overcome the defects and provide a device and a method for testing the optical axis thermal stability of an infrared sighting device, so that the problem that the optical axis thermal drift condition of the infrared sighting device under different temperature conditions can be accurately tested and obtained by effectively avoiding the measurement error caused by the poor anti-interference capability of a goniometer and an infrared thermal radiation target in the traditional testing method can be solved.
The technical scheme of the invention is as follows:
the utility model provides a testing arrangement of infrared sight optical axis thermal stability, includes optical platform, target, temperature test case, frock flange, theodolite, image acquisition and display device, infrared collimator, first speculum level second reflector.
The optical platform is used as a stable supporting device of a target and an infrared collimator and provides a stable target object; the infrared collimator is arranged on the optical platform, the target is arranged at the side aperture of the collimator, and the first reflector is connected with the target to be used as the reference of the target; the temperature test box simulates different temperature environments of the product; the temperature test box is firmly connected with the infrared sight to be tested by the tool flange; the second reflector is installed on the tool flange and used as the reference of the infrared sighting device; the theodolite is placed between the collimator tube and the temperature test box and used for measuring an included angle between the first reflector and the second reflector, and the change condition of the included angle is measured through a front-back cross test of temperature change in the temperature test box, wherein the change is the optical axis drift amount of the infrared sighting device after the temperature change.
During testing, the temperature test box provides constant temperature conditions for the infrared sighting device, the tool flange and the second reflector in the temperature box, so that the inside and the outside of the infrared sighting device can completely reach the specified temperature; the theodolite measures an included angle between the first reflecting mirror and the second reflecting mirror; meanwhile, the position variation of the center position of the output infrared image relative to the infrared heat radiation target at the moment is recorded through an infrared sighting device; and calculating and analyzing the position variation corrected by the included angle variation to obtain the thermal drift of the optical axis and evaluate the thermal stability of the optical axis of the infrared thermal sight.
A method for testing the stability of an optical axis of an infrared sighting device comprises the following steps:
the method comprises the following steps: under the condition of initial temperature, firstly, aiming the infrared sighting device at the center or the nearby position of the infrared heat radiation target, reading out the coordinate position of the center position of the infrared sighting device relative to the infrared heat radiation target through an image acquisition and display device, namely the initial position of an optical axis, and recording as (X) 0 ，Y 0 ) The unit: a pixel.
Step two: the first and second mirrors were then separately aimed and measured for angle using a TM6100A theodolite, recorded as α 0 (X Trans 1-0 ，Y Trans 1-0 )、β 0 (X Trans 2-0 ，Y Trans 2-0 ) And using the formula (beta) 0 -α 0 )＝(X Trans 1-0 -X Trans 2-0 ，Y Trans 1-0 -Y Trans 2-0 ) Calculating the included angle between the two space angles and recording the included angle as gamma 0 ＝β 0 -α 0 The unit: in angular seconds.
Step three: and applying temperature change to the infrared sighting device (comprising the tool flange and the second reflector) through the temperature test box until the temperature change range of the test target is reached. In this process, the infrared sight does not operate.
Step four: starting the infrared sighting device, reading out the coordinate position of the center position of the infrared sighting device relative to the target, namely the total change position of the optical axis, and recording as (X) i ，Y i ) The unit: a pixel.
Step five: the angles of the first and second mirrors were separately aimed and measured with a TM6100A theodolite, recorded as
α i (X Trans 1-i ，Y Trans 1-i )、β i (X Trans 2-i ，Y Trans 2-i ) And using the formula (beta) i -α i )＝(X Trans 1-i -X Trans 2-i ，Y Trans 1-i -Y Trans 2-i ) Calculating the included angle between the two space angles, and recording gamma i ＝β i -α i The unit: angle seconds.
And through two tests of front and back intersection, the relation formula is obtained:
wherein, A = [ 1-1 ]]In order to convert the matrix, the first and second matrices,
for the measurement result, is>
Is the amount to be requested.
Correction quantity X amend 、Y amend And the measurement result gamma i (α i ，β i ) And gamma 0 (α 0 ，β 0 ) In this regard, the following relationship can be used to solve:
wherein, FOV is the angle of view of the infrared sighting device, N Upixel And N Vpixel The number of pixels in the horizontal and pitch directions of the detector of the infrared sight, respectively.
And finishing the test of the thermal stability of the optical axis of the infrared sighting telescope.
Compared with the prior art, the invention has the following advantages:
(1) The prior art generally requires that the angle measuring equipment has the capability of long-time stability, otherwise, the angle measuring equipment is interfered due to vibration of a temperature test box, instability of the angle measuring equipment or environmental noise, and unnecessary and unpredictable test errors are introduced. According to the invention, the measurement reference is separated from the measurement instrument reference by judging the change of the included angle, the measurement reference is the reflector 1, the stability of the measurement result is related to the stability of the position of the reflector 1, the influence of instability of the measurement instrument reference is avoided, the test error caused by instability of the measurement instrument reference in the long-time measurement process is effectively eliminated, and the harsh requirement of high-precision measurement on the stability of the test equipment is effectively reduced;
(2) The prior art has very high requirements on the measurement environment, needs the temperature test box and the measuring instrument to have higher degree of shock insulation treatment, prevents the interference of external environment or vibration to the measurement process, and leads to the construction cost of the type of laboratories to be constructed to be high, the quantity is small, the single project takes long time, and the service efficiency is low. The method only needs to set a reasonable optical platform to keep certain stability on the target, the testing environment has no high requirement, and the general temperature laboratory environment can also reach the higher precision requirement, so that the cost of building a laboratory is reduced, the number of laboratories can be increased under the condition of the same expenditure, and the detection efficiency is improved;
(3) The test precision of the invention is completed in the cross-checking environment based on the common temperature test, and the invention has good environmental adaptability and higher universality.
(4) The prior art can not separate and position the main influence factors of the optical axis drift of the test system and the measured object. The method can know and position the main influence factors of the optical axis drift amount by monitoring the change conditions of the included angles between the targets and the unique reference at the same time.
Drawings
FIG. 1: the invention discloses a composition schematic diagram of an optical axis thermal stability testing device.
FIG. 2: the invention discloses a schematic composition diagram of a testing device based on a conventional infrared collimator.
FIG. 3: the invention discloses a testing device based on a vibration isolation building body.
FIG. 4: the principle of the stability of the testing method is schematically shown.
FIG. 5 is a schematic view of: the principle schematic diagram of the second reflector optical axis variation measurement is disclosed.
FIG. 6: schematic refraction of light as it passes through the window film.
Reference numbers in the figures: optical platform 1, infrared collimator 2, target 3, temperature test case 4, frock flange 5, theodolite 6, image acquisition and display device 7, infrared sight 8, vibration isolation building 9, first speculum 13, second speculum 25.
Detailed Description
Example 1
As shown in fig. 1, a device for testing the optical axis thermal stability of an infrared collimator comprises an optical platform 1, an infrared collimator 2, a target 3, a temperature test box 4, a tooling flange 5, a TM6100A theodolite 6, an image acquisition and display device 7, an infrared collimator 8, a first reflector 13 and a second reflector 25;
the optical platform 1 is used as a stable supporting device for the infrared parallel light tube 2 and the target 3 and provides a stable target object; the infrared collimator 2 is arranged on the optical platform 1, the target 3 is arranged at the aperture of the side surface of the infrared collimator 2, and the first reflector 13 is arranged at the target 3 as a reference mirror representing the target 3; the temperature test box 4 is used for providing different temperatures for products, the second reflector 25 and the infrared sighting device 8 are fixedly connected to the tooling flange 5 and are arranged in the temperature test box 4, and the second reflector 25 is used as a reference of the infrared sighting device 8; the TM6100A theodolite 6 is arranged between the infrared collimator 2 and the temperature test box 4 and is used for measuring the change of the included angle of the first reflector 13 and the second reflector 25 under different temperature conditions; the image acquisition and display device 7 is used for acquiring and displaying an image of the infrared sight 8.
During testing, the temperature test box 4 provides a constant temperature condition for the infrared sight 8, the tool flange 5 and the first reflector 13 in the temperature box, so that the temperature completely reaches the specified temperature; the TM6100A theodolite 6 measures the variation of the included angle between the first reflector 13 and the second reflector 25; meanwhile, the position variation of the center position of the output infrared image relative to the infrared heat radiation target 3 under different temperature conditions is recorded through the infrared sighting device 8; and calculating and analyzing the position variation corrected by the included angle variation to obtain the thermal drift of the optical axis and evaluate the thermal stability of the optical axis of the infrared thermal sight.
The method for testing the stability of the optical axis of the infrared collimator based on the device for testing the thermal stability of the optical axis of the infrared collimator shown in fig. 1 comprises the following testing steps:
the method comprises the following steps: under the condition of initial temperature, firstly, the infrared sighting device 8 is aimed at the center or the nearby position of the target 3, the coordinate position of the center position of the infrared sighting device 8 relative to the target 3, namely the initial position of the optical axis is read out through the image acquisition and display device 7, and is recorded as (X) 0 ，Y 0 ) The unit: a pixel.
Step two: the optical axis space angles of the first mirror 13 and the second mirror 25 are then separately collimated and measured by the TM6100A theodolite 6, and the angle between the two space angles is read and recorded as (α) 0 ，β 0 ) The unit: in angular seconds.
Step three: the temperature change is applied to the infrared sighting device 8 (comprising the tool flange 5 and the second reflector 25) through the temperature test box 4 until the temperature change range of the test target is reached. In this process, the infrared sight 8 does not operate.
Step four: the infrared sight 8 is turned on and the red is read out by the image acquisition and display device 7The coordinate position of the center position of the outer sight 8 relative to the target 3, i.e., the total change position of the optical axis, is recorded as (X) i ，Y i ) The unit: a pixel.
Step five: the spatial angles of the optical axes of the first mirror 13 and the second mirror 25 were respectively aimed and measured with a TM6100A theodolite 6, and the angle between the two spatial angles was read and recorded as (. Alpha.) (α) i ，β i ) The unit: in angular seconds.
And then, through the data recorded in the first step and the fourth step, the data is the total optical axis drift amount of the thermal imager before and after the temperature change (including the position deviation caused by thermal deformation of the tool flange 5 and vibration of the testing environment, if the change is obvious, the correction amount needs to be set by the method, and the total optical axis drift amount is eliminated), so that the relation is obtained:
wherein, A = [ 1-1 ]]In order to convert the matrix, the first and second matrices,
for the measurement result, is>
Is the amount to be requested.
Calculating correction X by using the data obtained in the second step and the fifth step amend 、Y amend . Correction quantity X amend 、Y amend And the measurement result (. Alpha.) i ，β i ) And (alpha) 0 ，β 0 ) In this regard, the following relationship may be used to solve:
wherein, FOV is the angle of view of the infrared sighting device, N Upixel And N Vpixel The number of pixels in the horizontal and pitch directions of the detector, respectively. The formula is that the number of pixels corresponds to the angle of a view field, and the number of the pixels is converted intoThe number of angular seconds is changed to be equal to one pixel. The field angle corresponding to one pixel can be calculated by the field angle distributed to each pixel by the total field of the infrared sighting device. The image center is then shifted by a few pixels and can be converted to a shift of a few angular seconds.
According to the testing method, firstly, the total optical axis variation of the infrared sighting device is obtained through the first step and the fourth step (including the deviation generated when the infrared sighting device is driven to move by the tooling flange due to the self optical axis variation of the infrared sighting device and the vibration and the heat effect of the incubator), then the deviation generated when the tooling flange drives the infrared sighting device to move is obtained through the second step and the fifth step, and then the variation caused by the tooling flange is subtracted by the total variation to obtain the self optical axis variation of the infrared sighting device.
The disadvantages of this embodiment are mainly: the conventionally used infrared collimator 2 and target 3 need to be modified, so that the target 4 can clearly image, and the first reflector 13 can reflect light back to the TM6100A theodolite through the infrared collimator 2.
The embodiment has the following advantages: since the first reflector 13 represents the position of the target 3, the deviation limit of the observed target position can be eliminated as + -3 ", and the system precision can be improved from the original 6.63" to 6.32 ".
Example 2
As shown in fig. 2, in this embodiment, on the basis of embodiment 1, if an optical platform can stably support a conventional infrared collimator, and a test environment is independent, and there is not too much influence of people entering and exiting, a first reflecting mirror 13 is attached to a chassis housing of the infrared collimator 2, and at this time, the system precision needs to calibrate a target position deviation limit value in advance.
If the tooling flange 3 can accurately represent the reference of the infrared sighting device 8, the optical axis drift amount of the infrared sighting device 8 can be directly evaluated by the variation before and after the included angle.
The method for testing the stability of the optical axis of the infrared collimator based on the device for testing the thermal stability of the optical axis of the infrared collimator shown in fig. 2 comprises the following testing steps:
the method comprises the following steps: initially, the infrared sight 8 is first aimed at the center of the target 3.
Step two: the first mirror 13 and the second mirror 25 are then separately aimed and measured for angle using the TM6100A theodolite 6, recorded as α 0 (X Trans 1-0 ，Y Trans 1-0 )、β 0 (X Trans 2-0 ，Y Trans 2-0 ) And using the formula (beta) 0 -α 0 )＝(X Trans 1-0 -X Trans 2-0 ，Y Trans 1-0 -Y Trans 2-0 ) Calculating the included angle between the two space angles and recording the included angle as gamma 0 ＝β 0 -α 0 The unit: angle seconds.
Step three: and applying temperature change to the infrared sighting device 8 (comprising the tool flange 5 and the second reflector 25) through the temperature test box until the temperature change range of the test target is reached. In this process, the infrared sight 8 does not operate.
Step four: the infrared sight 8 is turned on and the infrared sight 8 is again aimed at the center of the target 3.
Step five: the first mirror 13 and the second mirror 25 are respectively aimed and measured at an angle, recorded as α, by a TM6100A theodolite 6 i (X Trans 1-i ，Y Trans 1-i )、β i (X Trans 2-i ，Y Trans 2-i ) And using formula (β) i -α i )＝(X Trans 1-i -X Trans 2-i ，Y Trans 1-i -Y Trans 2-i ) Calculating the included angle between the two space angles, and recording gamma i ＝β i -α i The unit: angle seconds.
Step six: using the formula gamma i -γ 0 And calculating the variation delta of the included angle, wherein the variation delta is the optical axis drift of the infrared sighting device 8 before and after the temperature change.
The accuracy of the present embodiment may be affected by errors introduced by the temperature effect of the tooling flange 3 itself, which is related to the design capability of the tooling flange 3 itself.
Example 3
As shown in fig. 3, the layout of the test system based on the vibration isolation building is used in the case that the optical platform cannot stably support the target and the infrared collimator. If experimental environment is very mixed and disorderly, personnel come and go frequently, in order to guarantee first speculum 13's spatial stability, this embodiment is at the bearing wall in worker's room or builds a vibration isolation building body 9 for install first speculum 13, with the absolute stability of guaranteeing first speculum 13. The testing step may be a step of selecting the step and the data processing and evaluating method of embodiment 1 or embodiment 2 according to the measurement accuracy required by the index of the infrared sight 8.
The main influence factors of the testing precision of the method mainly comprise the aiming precision e of the measuring equipment 1 Influence of reference plane mirror e 2 Influence of atmospheric heat effect on optical path e 3 Influence of the observation window e 4 Testing the influence of ambient temperature changes and vibrations on the position of the target and the measuring device e 5 The total system precision is the result of the synthesis of each influence
The following is a test accuracy analysis for the method of the invention:
a) The aiming accuracy of the device is the measurement accuracy of the device itself, here, e introduced by TM6100A theodolite 1 ＝0.5″；
b) The deviation Delta caused by the offset of the aiming point of the reference plane mirror mainly due to the change of the surface type is calculated by the formula
And d is the offset of the aiming point caused by vibration and temperature effect, and the maximum offset is estimated to be 6mm by taking a reflector with the diameter of 30mm as an example and referring to an actual measurement value. R is the equivalent curvature radius of the plane mirror and is expressed by the formula>
Calculating D =30mm, h is the plane mirror type deviation, and based on the formula->
Calculating that N is lightThe number of turns, calculated as the limit value N =2, λ is the test wavelength, where λ =632.8nm. The extreme state deviation is then->
In general, during the measurement, the total influence of the reference plane mirror on the basis of the uniform distribution of the deviation values in the high-low temperature chamber, which is subject to relatively large vibrations and relatively high randomness, is taken into account>
c) Atmospheric thermal effects are mainly due to the temperature characteristics of the refractive index of the gas on the light. According to the basic principle that light rays propagate in different media to generate refraction, when the refractive index of gas in a high-temperature and low-temperature box changes, the optical axis is necessarily shifted. According to the temperature characteristic of the refractive index of air, the refractive index n of the air is at t under the standard atmospheric pressure t Can be expressed as: n is t -1＝(n 15 -1)[1.0549/(1+0.00366t)]In the formula, n 15 The value of the refractive index of air at 15 ℃ is expressed as a function of the wavelength λ: (n) 15 -1)×10 8 ＝8342.1+2406030/(130-υ 2 )+15996/(38.9-υ 2 ) Where υ =1/λ (λ is expressed in microns). Taking a long-wave infrared band as an example, λ =10 μm, air refractive indexes at 55 ℃ and-40 ℃ are respectively calculated: n is 55 ＝1+2.39×10 -5 ，n -40 ＝1+3.37×10 -5 . According to the law of refraction, it is calculated that in the case of air uniformity, the optical axis deviation is about 0.01mrad due to the change in the refractive index of air, and the maximum deviation introduced due to the change in the refractive index of air is estimated to be Δ =6 ″ in consideration of the influences of the non-uniformity and humidity of air in the high and low temperature chambers, counted as a uniform distribution, and the influence of atmospheric heat on the optical path is counted
d) The effect of the observation window is related to the use of the window format. The invention uses plastic film (polystyrene film, hereinafter abbreviated as "polystyrene film")Plastic film) as an infrared window. The method has the advantages that the plastic film is thin (the original thickness is d =0.02mm, and the thickness is improved to be 0.1 mm), the influence on the optical axis is small in the process of changing the refractive index and the thickness of the plastic film due to temperature change in the high-low temperature test process, the defects are that the transmittance is low and the influence on the vibration is easy to be caused, and the influence on the optical axis caused by the vibration due to the temperature change are mainly analyzed in the following process under the condition that the requirement on the transmittance is not high in the optical axis stability test. According to the law of refraction: n is a radical of an alkyl radical 1 sinθ 1 ＝n 2 sinθ 2 In the formula, n 1 ,n 2 Is refractive index, θ 1 ,θ 2 The angle between the incident light and the normal and the angle between the refracted light and the normal are shown in fig. 6;
since the optical axis may not always be perpendicular to the plastic film, it is assumed that the incident light ray makes an angle θ with the normal to the plastic film 1 Angle, through the refraction back of plastic film, emergent ray is parallel with incident ray, but has taken place the translation, and the translation volume is: Δ d = d (tan θ) 1 -tanθ 2 ). The temperature effect of the plastic film is mainly reflected in two aspects, namely the change of the thickness and the change of the refractive index;
according to the reference data, the coefficient of thermal expansion of the plastic film is taken to be α =7 × 10 -5 and/K, assuming that the temperature change delta T =67K, the thickness change is delta 1 ＝α·d·ΔT＝9.4×10 -8 m, the amount of change is very small. Because the thickness of the plastic film is small, the optical axis deviation caused by uneven thermal expansion and gradient refractive index due to temperature gradient factors is also small, the uncertainty of the influence of high and low temperature environments on the plastic film window can be ignored;
the window film vibration caused by high and low temperature operation causes variations in the angle of incidence and shifts of the reflected light due to the irregularity and non-uniformity of such variations, and the magnitude of the shift is complicated to analyze, in which case it introduces uncertainties that can be analyzed experimentally. Test method 1: aligning the reflected cross image with theodolite at room temperature, and vibrating the window artificiallyAnd applying different pressure effects to deform the window film, the aligned cross image is shifted (obviously, the artificial effect is much larger than the shift caused by vibration of the high and low temperature boxes), the offset is tested by using a theodolite, and 8 tests are carried out, wherein the test result is as follows: 3 ", 2", 4 ", 2", 3 ", 0", 3 ", 2" the mean value of the deviations is: 2.37 ". Test method 2: the two theodolites are used for carrying out a visual inspection test through windows of the high-temperature and low-temperature boxes respectively, as shown in figure 2, the two theodolites are aligned at room temperature, then the temperatures of the high-temperature and low-temperature boxes are set to be 55 ℃ at high temperature and 40 ℃ below zero respectively, the influence of the vibration of the box body on the alignment of a cross cursor of the theodolite in the processes of temperature rise and temperature fall is considered, and the two experiments show that the deviation of the cross cursor of the theodolite caused by the vibration of the windows is very small in the whole process and generally does not exceed 3 ". From the above-described experiments and empirical summary, it was judged that the maximum deviation Δ =5 "due to the vibration of the window film. According to normal distribution, the effect of the film as a window on observation
e) The influence of the test environment temperature change and vibration on the target position and the measuring equipment is the influence of the test environment on the test system, and mainly comprises the change of the environment temperature and humidity, the environment vibration (mainly foundation vibration and sound vibration) and the atmospheric disturbance influence caused by test personnel in the moving process, wherein the influence factors cause the tiny change of the optical axis position of the infrared collimator and the observation target position on one hand, and influence the alignment precision of the TM6100A theodolite on the other hand;
the small changes of the optical axis position of the infrared collimator and the position of the observation target adopt a B-type evaluation method, and in an effective test period (8 hours here), according to the working characteristics of a test device and a system, the deviation limit of the optical axis position of the infrared collimator is estimated to be +/-0.5 ", and the deviation limit of the observation target position is +/-3". According to a normal distribution when
The influence of the environment on the alignment accuracy of the TM6100A theodolite is evaluated by moving the TM6100A theodolite across the alignment targets, and the results are calculated using a class a evaluation method. The measuring method comprises the following steps: setting a reference reflector 1 representing a target position and a second reflector 25 placed in a temperature test box, respectively measuring an angle alpha of a first reflector 13 and an angle beta of a target reflector 2 by using a TM6100A theodolite, calculating an included angle gamma = beta-alpha, evaluating the change of the included angle gamma before and after moving the TM6100A theodolite, repeatedly measuring for 10 times, and calculating a deviation delta;
statistical standard deviation at-45 ℃: sigma x ＝2.41″，σ y =1.61 ", the repeated measurement deviation is:
statistical standard deviation at-20 ℃: sigma x ＝1.66″，σ y =1.43 ", the repeated measurement deviation is:
statistical standard deviation of +35 ℃: sigma x ＝1.50″，σ y =1.70 ", the repeated measurement deviation is:
statistical standard deviation of +65 ℃: sigma x ＝2.10″，σ y =1.12 ", repeated measurement deviations are:
according to a normal distribution when counting
The total impact of the test environment on the test system is:
f) The total accuracy of the system is the synthetic result of each influence:
the test precision of the invention is completed in the cross-checking environment based on the common temperature test, and the invention has good environmental adaptability and higher universality.
Claims (8)
1. The utility model provides a testing arrangement of infrared sight optical axis thermal stability which characterized in that:
the testing device comprises an optical platform (1), an infrared collimator (2), a target (3), a temperature test box (4), a tool flange (5), a theodolite (6), image acquisition and display equipment (7), an infrared sighting device (8), a first reflector (13) and a second reflector (25); along the light reciprocating direction, the theodolite (6) is positioned between the optical platform (1) and the temperature test box (4) and is used for measuring the change condition of the included angle between the first reflector (13) and the second reflector (25) under different temperature conditions; the infrared collimator (2) is arranged on the optical platform (1), the target (3) is arranged at the side aperture of the infrared collimator (2), and the first reflector (13) is arranged at the target (3) as a reference mirror representing the target (3); the temperature test box (4) is used for providing different temperatures, the second reflecting mirror (25) and the infrared sighting device (8) are fixedly connected to the tool flange (5) and are arranged in the temperature test box (4), and the second reflecting mirror (25) is used as the reference of the infrared sighting device (8); the image acquisition and display device (7) is used for connecting, acquiring and displaying the image of the infrared sighting device (8).
2. The utility model provides a testing arrangement of infrared sight optical axis thermal stability which characterized in that:
the testing device comprises an optical platform (1), an infrared collimator (2), a target (3), a temperature test box (4), a tooling flange (5), a theodolite (6), image acquisition and display equipment (7), an infrared sighting device (8), a first reflector (13) and a second reflector (25); along the light reciprocating direction, the theodolite (6) is positioned between the optical platform (1) and the temperature test box (4) and is used for measuring the change condition of the included angle between the first reflector (13) and the second reflector (25) under different temperature conditions; the infrared collimator (2) is arranged on the optical platform (1), the target (3) is arranged at the aperture of the side face of the infrared collimator (2), and the first reflector (13) is attached to the case shell of the infrared collimator (2); the temperature test box (4) is used for providing different temperatures, the second reflecting mirror (25) and the infrared sighting device (8) are fixedly connected to the tool flange (5) and are arranged in the temperature test box (4), and the second reflecting mirror (25) is used as the reference of the infrared sighting device (8); the image acquisition and display device (7) is used for connecting, acquiring and displaying the image of the infrared sighting device (8).
3. The utility model provides a testing arrangement of infrared sight optical axis thermal stability which characterized in that:
the testing device comprises an optical platform (1), an infrared collimator (2), a target (3), a temperature test box (4), a tool flange (5), a theodolite (6), image acquisition and display equipment (7), an infrared sighting device (8), a vibration isolation building body (9), a first reflector (13) and a second reflector (25); the vibration isolation building body (9) is positioned on the side surface of the theodolite (6); along the light reciprocating direction, the theodolite (6) is positioned between the optical platform (1) and the temperature test box (4) and is used for measuring the change condition of an included angle between the first reflector (13) and the second reflector (25) under different temperature conditions; the infrared collimator (2) is installed on the optical platform (1), the target (3) is installed at the aperture of the side face of the infrared collimator (2), and the first reflector (13) is installed on the wall face of the vibration isolation building body (9); the temperature test box (4) is used for providing the temperature of a product, the second reflecting mirror (25) and the infrared sighting device (8) are fixedly connected to the tooling flange (5) and are placed in the temperature test box (4), and the second reflecting mirror (25) is used as the reference of the infrared sighting device (8); the image acquisition and display device (7) is used for connecting, acquiring and displaying the image of the infrared sighting device (8).
4. A test device according to any one of claims 1-3, wherein:
the theodolite (6) adopts a TM6100A theodolite.
5. A test device according to any one of claims 1-3, wherein:
the infrared window of the infrared sighting device adopts a polystyrene film.
6. The test device of claim 5, wherein:
the thickness of the polystyrene film is 0.1mm.
7. A method for testing the thermal stability of the optical axis of an infrared collimator, which uses the device for testing the thermal stability of the optical axis of an infrared collimator as claimed in claim 1 or 3, and the testing steps include:
the method comprises the following steps: under the condition of initial temperature, firstly aiming an infrared sighting device (8) at the center or the nearby position of a target (3), reading the coordinate position of the center position of the infrared sighting device (8) relative to the target (3), namely the initial position of an optical axis through an image acquisition and display device (7), and recording as (X) 0 ，Y 0 ) The unit: a pixel;
step two: then, the theodolite (6) is used for respectively aiming and measuring the optical axis space angles of the first reflecting mirror (13) and the second reflecting mirror (25), the included angle between the two space angles is read out and recorded as alpha 0 ，β 0 ) The unit: angular seconds;
step three: applying temperature change to the infrared sighting device (8), the tool flange (5) and the second reflector (25) through the temperature test box (4) until the temperature change range of a test target is reached, wherein the infrared sighting device (8) does not work in the process;
step four: starting the infrared sighting device (8), reading out the coordinate position of the central position of the infrared sighting device (8) relative to the target (3), namely the total change position of the optical axis through the image acquisition and display equipment (7), and recording as (X) i ，Y i ) The unit: a pixel;
step five: aiming and measuring the optical axis space angles of the first reflector (13) and the second reflector (25) respectively by a theodolite (6), reading the included angle between the two space angles, and recording the included angle as alpha i ，β i ) The unit: angular seconds;
step six: and obtaining the following relation through the data recorded in the first step and the fourth step:
wherein: a = [ 1-1 ]]In order to convert the matrix, the first and second matrices,
for the measurement result, is>
As a quantity to be sought, X amend 、Y amend Is the correction amount;
the data obtained in the second step and the fifth step are used for calculating X amend 、Y amend ；X amend 、Y amend And the measurement result (alpha) i ，β i ) And (alpha) 0 ，β 0 ) On, the following relation is used to solve:
wherein: FOV is the angle of view of the infrared sight (8), N Upixel And N Vpixel The number of pixels in the horizontal direction and the pitch direction of the detector of the infrared sighting device (8) respectively.
8. A method for testing the thermal stability of the optical axis of an infrared collimator, which uses the device for testing the thermal stability of the optical axis of an infrared collimator as claimed in claim 2 or 3, and the testing steps include:
the method comprises the following steps: under the condition of initial temperature, firstly aiming an infrared sighting device (8) at the center of a target (3);
step two: the theodolite (6) is then used to aim and measure the angles of the first (13) and second (25) mirrors, recorded as alpha 0 (X Trans 1-0 ，Y Trans 1-0 )、β 0 (X Trans 2-0 ，Y Trans 2-0 ) And using the formula (beta) 0 -α 0 )＝(X Trans 1-0 -X Trans 2-0 ，Y Trans 1-0 -Y Trans 2-0 ) Calculating the included angle gamma between the two space angles 0 Is recorded as gamma 0 ＝β 0 -α 0 The unit: angular seconds;
step three: applying temperature change to the infrared sighting device (8), the tool flange (5) and the second reflector (25) through a temperature test box to reach a test target temperature change range, wherein the infrared sighting device (8) does not work in the process;
step four: starting the infrared sighting device (8), and aiming the infrared sighting device (8) at the center of the target (3) again;
step five: the angles of the first reflector (13) and the second reflector (25) are respectively aimed and measured by a theodolite (6) and are respectively recorded as alpha i (X Trans 1-i ，Y Trans 1-i )、β i (X Trans 2-i ，Y Trans 2-i ) And using the formula (beta) i -α i )＝(X Trans 1-i -X Trans 2-i ，Y Trans 1-i -Y Trans 2-i ) Calculating the included angle gamma between the two space angles i Recording of gamma i ＝β i -α i The unit: angular second;
step six: using the formula Δ = γ i -γ 0 And calculating the variation delta of the included angle, wherein the variation delta is the optical axis drift of the infrared sighting telescope (8) before and after the temperature change.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116625241A (en) * | 2023-07-24 | 2023-08-22 | 北京瑞控信科技股份有限公司 | Quick reflection mirror temperature drift measuring and correcting system and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116625241A (en) * | 2023-07-24 | 2023-08-22 | 北京瑞控信科技股份有限公司 | Quick reflection mirror temperature drift measuring and correcting system and method |
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