CN111721225B - Dynamic measurement method and device for temperature deformation in high-temperature environment - Google Patents

Dynamic measurement method and device for temperature deformation in high-temperature environment Download PDF

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CN111721225B
CN111721225B CN202010583274.3A CN202010583274A CN111721225B CN 111721225 B CN111721225 B CN 111721225B CN 202010583274 A CN202010583274 A CN 202010583274A CN 111721225 B CN111721225 B CN 111721225B
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冯雪
岳孟坤
张金松
屈哲
唐云龙
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Tsinghua University
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Abstract

The disclosure relates to a method and a device for dynamically measuring temperature deformation in a high-temperature environment, wherein the method comprises the following steps: acquiring a first image of the surface of a measured object in a heating process and an initial image of the surface of the measured object when the surface is not heated; correcting the initial image according to a first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image; and the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image. According to the method and the device, the influence of nonlinear brightness change caused by radiation on the deformation field measurement can be eliminated, and the high-precision deformation field measurement is realized.

Description

Dynamic measurement method and device for temperature deformation in high-temperature environment
Technical Field
The present disclosure relates to the field of optical measurement technologies, and in particular, to a method and an apparatus for dynamically measuring temperature deformation in a high temperature environment, and a storage medium.
Background
When the high-temperature structural material is examined in the fields of aerospace, gas turbines and the like, the method has important significance for overcoming the influence of high-temperature environment on optical measurement, particularly the influence of high-light radiation interference even submergence optical information.
In the related technology, the method can be insensitive to the linear change of the light intensity or weaken the influence of the temperature change on the brightness, but the nonlinear brightness change caused by radiation cannot be completely eliminated, so that the precision of the deformation field measurement is reduced; meanwhile, the accuracy of temperature field measurement will be affected by enhancing the externally added compensation brightness to weaken the influence caused by temperature change.
Disclosure of Invention
In view of the above, the present disclosure provides a method and an apparatus for dynamically measuring temperature deformation in a high temperature environment, and a storage medium.
According to an aspect of the present disclosure, there is provided a temperature deformation dynamic measurement method, including:
acquiring a first image of the surface of a measured object in a heating process and an initial image of the surface of the measured object when the surface is not heated;
correcting the initial image according to a first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image;
and the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image.
In one possible implementation, the method further includes:
correcting the first image according to the first deformation field and a second relational expression; obtaining a temperature field of the measured object according to the corrected first image and the reference point temperature;
the second relational expression represents the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image, and the reference point temperature is the single-point temperature of the surface of the measured object when the first image is shot.
In a possible implementation manner, the first relation represents a luminance variation relationship between the blue light channel of the first image and each pixel point in the blue light channel of the initial image, and the method further includes:
obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image;
removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image;
and fitting the brightness difference of each pixel point of the blue light channel in the blue light channel intermediate image and the initial image to obtain the first relational expression.
In a possible implementation manner, the initial image is corrected according to a first relational expression; and according to the corrected initial image and the first image, obtaining a first deformation field of the measured object, comprising:
determining the brightness correction quantity of each pixel point in the initial image according to the first relational expression;
correcting the blue light channel of the initial image through the brightness correction amount of each pixel point to obtain a blue light channel reference image;
and obtaining the first deformation field according to the blue light channel reference image and the gray value of the blue light channel of the first image.
In one possible implementation, the second relation includes: a red light channel relation and a green light channel relation;
the method further comprises the following steps:
acquiring a second image sequence of the surface of the measured object, which is shot under different exposure times when the measured object is not heated;
extracting a red light channel and a green light channel of the second image sequence;
and fitting the gray values of the pixel points in the red light channel and the green light channel and the corresponding exposure time to obtain the red light channel relational expression and the green light channel relational expression.
In a possible implementation manner, the first image is corrected according to the first deformation field and a second relational expression; and according to the corrected first image and the reference point temperature, obtaining the temperature field of the measured object, including:
respectively removing displacement values in a red light channel and a green light channel of the first image according to the first deformation field to obtain a red light channel intermediate image and a green light channel intermediate image;
determining a red light channel gray value correction amount and a green light channel gray value correction amount according to the exposure time for shooting the first image, the red light channel relational expression and the green light channel relational expression;
correcting the gray value of the intermediate image of the red light channel through the gray value correction quantity of the red light channel to obtain a reference image of the red light channel;
correcting the gray value of the green light channel intermediate image through the green light channel gray value correction quantity to obtain a green light channel reference image;
and obtaining the temperature field of the measured object according to the red light channel reference image, the green light channel reference image and the reference point temperature.
In a possible implementation manner, the initial image is corrected according to a first relational expression; and according to the corrected initial image and the first image, obtaining a first deformation field of the measured object, comprising:
obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image;
removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image;
fitting the brightness difference of each pixel point in the blue light channel of the intermediate image of the blue light channel and the initial image to obtain the first relational expression;
correcting the initial image according to the first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image;
and repeatedly executing the operations of obtaining the intermediate image of the blue light channel and the subsequent operations according to the obtained first deformation field and the blue light channel of the first image until a preset iteration condition is met.
According to another aspect of the present disclosure, there is provided a temperature deformation dynamic measurement apparatus including:
the image acquisition module is used for acquiring a first image of the surface of the object to be measured in the heating process and an initial image of the surface of the object to be measured in the unheated process;
the deformation field obtaining module is used for correcting the initial image according to a first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image;
and the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image.
According to another aspect of the present disclosure, there is provided a temperature deformation dynamic measurement apparatus including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to perform the above method.
According to another aspect of the present disclosure, there is provided a non-transitory computer readable storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by a processor, implement the above-described method.
In the embodiment of the disclosure, the initial image is corrected according to the brightness change relationship between the first image and each pixel point in the initial image, so that a first deformation field of the measured object is obtained according to the corrected initial image and the first image; the influence of nonlinear brightness change caused by radiation on the deformation field measurement can be eliminated, and the high-precision deformation field measurement is realized.
Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.
FIG. 1 shows a blue channel gray scale map of an experimental initial image;
FIG. 2 shows a blue channel grayscale map of a current image after heating resulting in non-uniform changes in brightness;
FIG. 3 illustrates a flow chart of a method of dynamic measurement of temperature deformation according to an embodiment of the present disclosure;
FIG. 4 illustrates a flow chart of a method of dynamic measurement of temperature deformation according to an embodiment of the present disclosure;
FIG. 5 shows an image of a green channel containing reflected light interference;
FIG. 6 shows an image of a green channel free of reflected light interference;
FIG. 7 shows a block diagram of a dynamic measurement device for temperature deformation according to an embodiment of the present disclosure;
FIG. 8 shows a block diagram of a dynamic measurement device for temperature deformation according to an embodiment of the present disclosure;
fig. 9 shows a block diagram of a dynamic measurement device for temperature deformation according to an embodiment of the present disclosure.
Detailed Description
Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present disclosure may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present disclosure.
In the fields of aerospace, gas turbines and the like, many key structural components face the examination of high-temperature complex environment under working conditions, which provides great challenge for the on-line and in-situ examination technology of material performance. On one hand, the high-temperature environment can greatly affect contact type measuring devices, circuits and the like; on the other hand, phenomena such as strong light radiation and air flow disturbance generated in a high-temperature environment also put higher demands on a non-contact measurement technology based on optical information. In general, however, the non-contact optical measurement provides a feasible solution under the condition that the contact measurement is subject to failure in a high-temperature and ultrahigh-temperature environment due to the advantages of full-field measurement, simple equipment, strong environmental adaptability, small influence of temperature and the like.
In the examination of high-temperature structural materials, temperature and deformation are the physical quantities of primary concern. Currently, non-contact deformation measurement methods based on optical principles include interferometry, diffraction, photoelastic, digital image correlation, and the like. With the development of computer graphics and image processing technology, the digital image correlation method is gradually developed into the most mature method in non-contact high-temperature deformation measurement due to the characteristics of high precision, simple equipment, strong environmental interference resistance and the like; the colorimetric method is a mature non-contact temperature measurement method at present.
According to the wien equation, considering the composition of the actual imaging system, the luminance value I finally received by the camera can be expressed as the following formula:
Figure BDA0002553230410000061
wherein A (c, t, a) is a photoelectric conversion coefficient of the camera, c is photoelectric characteristics, t is exposure time, and a is relative aperture size; k (λ) is the optical system transmittance with respect to the wavelength (λ); t is the temperature; c1、C2Is an empirical constant; h (λ) is a spectral response characteristic function (h (λ) can be set at a wavelength λcIs equivalent to having an intensity h (λ)c) Sampling function of).
For the influence of high temperature environment on optical measurement, fig. 1 shows a blue light channel gray scale map of an experimental initial image; FIG. 2 shows a blue channel grayscale map of a current image after heating resulting in non-uniform changes in brightness; as shown in fig. 1 and fig. 2, the optical information is even submerged by the interference of high light radiation, and in the present deformation measurement method based on digital image processing, insensitivity to linear variation of light intensity can be realized by selecting a correlation coefficient; however, in the high temperature optical measurement, according to the above formula of the brightness value finally received by the camera, the temperature change (even linear change) causes the non-linear change of the light intensity received by the camera. The non-linear change of the light intensity will interfere with the matching of the image, thereby affecting the precision of the deformation measuring method based on digital image processing and even causing the failure of the method. Although narrow-band filters can be used in combination with a high-brightness narrow-band light source to reduce the effect of temperature variation on brightness in conventional deformation measurement based on digital image processing, the effect cannot be completely eliminated. Meanwhile, if a single camera is used for synchronously measuring the temperature field and the deformation field, the spectral response bandwidth of a blue light channel is wide due to the limitation of an existing filter of the existing camera, and the influence of the nonlinear brightness change caused by the radiation light still exists.
Therefore, in order to eliminate the influence of strong light radiation on the deformation measurement precision, the technical scheme for high-precision dynamic measurement of temperature deformation in a high-temperature environment is provided, the initial image is corrected according to the brightness change relationship between the image acquired in the heating process and each pixel point in the initial image, so that the deformation field of the object to be measured is obtained according to the corrected initial image and the acquired image, the influence of nonlinear brightness change caused by radiation on the deformation field measurement is eliminated, and the high-precision deformation field measurement is realized.
Fig. 3 shows a flow chart of a method for dynamic measurement of temperature deformation according to an embodiment of the present disclosure. The method can be used for dynamically measuring the temperature deformation in a high-temperature environment. As shown in fig. 3, the method may include:
step 101, acquiring a first image of the surface of a measured object in a heating process and an initial image of the surface of the measured object when the measured object is not heated;
exemplarily, high-temperature speckles can be prepared on the surface of a measured object or the surface texture of the measured object is used as the speckles, the measured object is fixed on an object stage, and an image of the measured object is shot by an image acquisition device to be used as an initial image; then utilize heating device to this measured object heating, in the heating process, utilize image acquisition device to shoot the image of measured object, as first image, first image can be many, corresponds different acquisition moments respectively. Wherein, image acquisition device can be: an industrial color Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) camera with a blue band-pass filter mounted on a lens can utilize a blue light source to supplement light when shooting images, and the captured images can be ensured to be clear by adjusting exposure time without over-exposure.
In one possible implementation, the method further includes: obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image; removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image; fitting the brightness difference of each pixel point of the blue light channel in the blue light channel intermediate image and the initial image to obtain a first relational expression, wherein the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image; for example, the first relation may represent a relationship between a blue light channel of the first image and a luminance variation of each pixel point in the blue light channel of the initial image. The first relation may be used to correct the initial image to obtain a first deformation field of the measured object, and a related scheme of the first relation will be described in detail later.
In the embodiment of the disclosure, the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image can be extracted, and the second deformation field of the object to be measured is calculated by adopting a digital image correlation method according to the gray values of the blue light channels; restoring the blue light channel of the first image to a blue light channel intermediate image through a second deformation field, namely traversing all pixel points of the blue light channel of the first image, and subtracting the displacement value of the pixel point in the second deformation field from the position coordinate of each pixel point to obtain a corresponding blue light channel intermediate image, wherein the blue light channel intermediate image only contains brightness change caused by high-temperature radiation compared with a blue light channel gray-scale image of the initial image, namely the blue light channel intermediate image represents the brightness change of the first image in the blue light channel relative to the initial image; and then fitting the difference of the brightness (gray value) of each pixel point in the blue light channel intermediate image and the initial image blue light channel to obtain a first relational expression.
It should be noted that, considering that the distribution of the material of the object to be measured is not uniform, and the radiation influence on each pixel point is not the same (for example, the middle area of flame heating is greatly influenced by radiation, and the edge area is less influenced), when the fitting process is performed on the brightness difference between each pixel point in the blue light channel of the intermediate image and the initial image of the blue light channel, a sub-area fitting mode can be adopted, so as to obtain a more accurate fitting result; specifically, the intermediate image and the initial image of the blue light channel may be divided into a plurality of sub-regions, each sub-region has a size not smaller than 2 × 2 pixels, the luminance (gray value) of a pixel point in the intermediate image of the blue light channel in a certain sub-region is different from the luminance (gray value) of the pixel point in the blue light channel of the initial image, a luminance variation (difference between gray values) corresponding to each pixel point in the sub-region is obtained after traversing all the pixel points in the sub-region, the luminance variation corresponding to each pixel point in the sub-region is subjected to fitting processing (which may be in a functional form such as an exponential function, a linear function, a quadratic function, etc.), a luminance variation optical system corresponding to the sub-region is obtained, and all the sub-regions are traversed, thereby obtaining a piecewise continuous luminance variation optical system.
Illustratively, the first image P is extractedmBlue light channel ofThe gray scale image is marked as BmExtracting an initial image P0The blue light channel gray scale image is marked as B0(ii) a According to B0And BmAnd calculating a second deformation field (u) using a digital image correlation method1,v1) The second deformation field includes the displacement value of each pixel point in the blue light channel from the initial image to the first image. B is to bemBy (u)1,v1) Restore to blue channel intermediate image Bm_ref_1(i.e., traverse all pixel points, subtract the displacement value of each pixel point), Bm_ref_1And B0Compared with the method only comprising brightness change caused by high-temperature radiation; b is to bem_ref_1And B0Dividing into a plurality of sub-regions, each sub-region taking 3 × 3 pixels in size, assuming B for each sub-regionm_ref_1And B0The brightness is changed in an exponential function, and the brightness change relation is calculated from sub-region to sub-region (for example, by using the optimum square approximation or least square method), so as to obtain the first relation Li_ref_1(x, y), wherein x and y are coordinates of the pixel points, and i is the ordinal number of the subarea. By knowing the coordinates of any pixel point through the first relational expression, the brightness of the pixel point in the blue light channel of the first image can be calculated relative to the brightness of the blue light channel of the initial image.
Step 102, correcting the initial image according to a first relational expression; and obtaining a first deformation field of the measured object according to the corrected initial image and the first image.
The brightness of each pixel point in the initial image can be corrected according to the first relational expression, the corrected initial image has only displacement change but no brightness change compared with the first image, and then the gray value of the blue light channel of the corrected initial image and the gray value of the blue light channel of the first image can be extracted.
In a possible implementation manner, the initial image is corrected according to a first relational expression; and according to the corrected initial image and the first image, obtaining a first deformation field of the measured object, comprising: determining the brightness correction quantity of each pixel point in the initial image according to the first relational expression; correcting the blue light channel of the initial image through the brightness correction amount of each pixel point to obtain a blue light channel reference image; and obtaining the first deformation field according to the blue light channel reference image and the gray value of the blue light channel of the first image.
In the embodiment of the present disclosure, in consideration of the influence of the nonlinear brightness change caused by the radiation light, the second deformation field obtained by the first image and the original initial image has a deviation from the real deformation field, and therefore, the brightness change of the first image represented by the intermediate image of the blue light channel in the blue light channel relative to the initial image is not the real brightness change but is a rough approximation of the real brightness change, and therefore, the brightness of each pixel point in the initial image is corrected according to the first relational expression having a good approximation of the real brightness change, so as to obtain the accurate first deformation field. Specifically, according to the coordinates of each pixel point in the initial image and the ordinal number of the sub-region in which each pixel point is located, a first relational expression is combined to obtain a brightness correction amount (gray value correction amount, which is referred to as brightness change in the foregoing) of the pixel point, the gray value correction amount is added to the gray value of the original blue light channel of the pixel point in the initial image to obtain a gray value of the blue light channel corrected by the pixel point, all the pixel points in the initial image are traversed, and thus a blue light channel reference image is obtained. And further obtaining a first deformation field based on a digital image correlation method according to the blue light channel reference image and the gray value of the blue light channel of the first image.
Illustratively, the first relation Li_ref_1(x, y) superimposed on the above B0I.e. B0The coordinate value of each pixel point and the ordinal number of the sub-region are substituted into the first relational expression Li_ref_1(x, y), and then subjecting the obtained bright toCorrection amount and B0Adding the gray values of the pixel points to obtain a blue light channel reference image B only containing brightness change0_1Using B0_1And the first image BmCalculating to obtain a first deformation field (u) based on a digital image correlation method2,v2)。
In a possible implementation manner, the initial image is corrected according to a first relational expression; and according to the corrected initial image and the first image, obtaining a first deformation field of the measured object, comprising: obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image; removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image; fitting the brightness difference of each pixel point in the blue light channel intermediate image and the initial image to obtain the first relational expression; correcting the initial image according to the first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image; and repeatedly executing the operations of obtaining the intermediate image of the blue light channel and the subsequent operations according to the obtained first deformation field and the blue light channel of the first image until a preset iteration condition is met.
In the embodiment of the present disclosure, in order to further improve the accuracy of the obtained first deformation field, the above steps are repeated by using the obtained first deformation field in an iterative processing manner, and the first deformation field obtained in the previous iteration period and the blue light channel of the first image are used to obtain the blue light channel intermediate image in the current iteration period, and then obtain a new first relational expression in the current iteration period, and obtain a new deformation field, and the above steps are repeated until the iteration condition is satisfied, so as to obtain a final deformation field, thereby obtaining a more accurate measurement result of the deformation field while eliminating the influence of the nonlinear brightness change caused by radiation on the measurement of the deformation field. Wherein the iteration condition may include: the iteration times are less than a threshold h; iterative residual error delta u < ru,Δv＜rvThreshold values h and ru、rvThe specific numerical value can be set according to the actual requirement and the calculation precision requirement, and is not limited herein; the total field deformation field obtained finally is (u)c,vc) And c is the actual number of iterations.
Fig. 4 shows a flow chart of a method for dynamic measurement of temperature deformation according to an embodiment of the present disclosure. As shown in fig. 4, in one possible implementation, the method further includes:
103, correcting the first image according to the first deformation field and a second relational expression; obtaining a temperature field of the measured object according to the corrected first image and the reference point temperature; the second relational expression represents the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image, and the reference point temperature is the single-point temperature of the surface of the measured object when the first image is shot.
In the disclosed embodiment, considering that in the related art, a high-brightness light source is generally used, the non-linear influence of the temperature change on the brightness is weakened in the conventional deformation measurement based on digital image processing. However, this approach can cause excessive reflected light to enter the red and green channels of the camera, causing the red and green channels for colorimetric thermometry to be brightness-doped with reflected light, resulting in inaccurate temperature measurements, as shown in fig. 5 and 6, fig. 5 showing an image of the green channel containing reflected light interference; fig. 6 shows an image of the green channel without reflection interference. Therefore, the first image is corrected by combining the obtained first deformation field through the relationship between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image; obtaining a temperature field of the measured object based on a colorimetric temperature measurement method according to the corrected first image and the reference point temperature; therefore, on the basis of eliminating the influence of nonlinear brightness change caused by radiation on deformation field measurement, the problem of inaccurate temperature measurement caused by high-brightness reflected light is further solved, so that high-precision synchronous online measurement of temperature and deformation is realized, the method is vital to strain decoupling, process information acquisition and the like, the mechanism of material evolution is disclosed, and meanwhile, the method can adapt to synchronous online measurement of the temperature field and the deformation field under the condition that exposure time is dynamically adjusted under a high-temperature environment to obtain a clear surface image.
In one possible implementation, the second relation includes: a red light channel relation and a green light channel relation; the method further comprises the following steps: acquiring a second image sequence of the surface of the measured object, which is shot under different exposure times when the measured object is not heated; extracting a red light channel and a green light channel of the second image sequence; and fitting the gray values of the pixel points in the red light channel and the green light channel and the corresponding exposure time to obtain the red light channel relational expression and the green light channel relational expression.
In the embodiment of the disclosure, before heating a fixed measured object, the exposure time can be gradually adjusted, and the image acquisition device is used for shooting the images of the surface of the measured object at different exposure times to serve as a second image sequence, wherein the adjustment interval of the exposure time covers the range as large as possible, so that the exposure time during shooting in the subsequent actual heating process falls within the interval; the second image is an image shot when the second image is not heated, so that the gray value of each pixel point in the second image is the intensity of the reflected light, all the pixel points in the second image sequence are traversed, and a function of the intensity of the reflected light and the exposure time, namely a second relational expression, is obtained by adopting a proper function form (such as a linear function) fitting; specifically, aiming at a certain pixel point, extracting the gray values of the red light channels of the pixel point in all second images of the second image sequence, fitting the gray values of the red light channels of all the second images and the exposure time corresponding to each second image to obtain a red light channel relational expression of the pixel point, traversing all the pixel points to obtain a red light channel relational expression of all the pixel points, wherein the relational expression represents the relationship between the reflected light intensity of each pixel point in the red light channel and the corresponding exposure time; similarly, fitting the gray value of each pixel point in the green light channel in the second image sequence and the corresponding exposure time to obtain a green light channel relational expression of each pixel point, wherein the relational expression represents the relationship between the reflected light intensity of each pixel point in the green light channel and the corresponding exposure time.
Exemplarily, before the fixed object to be measured is heated, the ambient light source is turned off, the blue light source is turned on, and the focal length of the camera is adjusted, so that the image shot by the camera is clear and the visual field is appropriate; under the condition of meeting the set camera acquisition frame rate requirement and avoiding the overexposure phenomenon, the exposure time is adjusted to the maximum T0Then, the aperture of the camera is adjusted from small to large until the maximum brightness of the shot image reaches the overexposure critical point (i.e. the maximum gray-scale value of the image is 2)p1, p is the image bit depth), the camera aperture is fixed, and the surface image of the measured object at the moment is shot and recorded as F0(ii) a Reducing the exposure time value step by step to
Figure BDA0002553230410000121
(N is the preset total exposure time adjustment times, N is the current adjustment times), and the surface image of the measured object at the moment is shot and recorded as Fn(ii) a And so on until N equals N, obtaining a second image sequence F0～Fn(ii) a Extraction of F0～FnTraversing all the pixel points according to the gray values of the red light channel and the green light channel, respectively fitting the gray value of the red light channel of each pixel point and the corresponding exposure time by adopting a linear function form, and obtaining a red light channel relational expression F of each pixel pointR(ii) a Fitting the gray value of the green light channel with the corresponding exposure time to obtain a green light channel relational expression F of each pixel pointG。
In a possible implementation manner, the first image is corrected according to the first deformation field and a second relational expression; and according to the corrected first image and the reference point temperature, obtaining the temperature field of the measured object, including: respectively removing displacement values in a red light channel and a green light channel of the first image according to the first deformation field to obtain a red light channel intermediate image and a green light channel intermediate image; determining a red light channel gray value correction amount and a green light channel gray value correction amount according to the exposure time for shooting the first image, the red light channel relational expression and the green light channel relational expression; correcting the gray value of the intermediate image of the red light channel through the gray value correction quantity of the red light channel to obtain a reference image of the red light channel; correcting the gray value of the green light channel intermediate image through the green light channel gray value correction quantity to obtain a green light channel reference image; and obtaining the temperature field of the measured object according to the red light channel reference image, the green light channel reference image and the reference point temperature.
In the embodiment of the disclosure, when a measured object is heated, an experimental image sequence, an exposure time sequence and a reference point temperature sequence are synchronously obtained; extracting a red light channel and a green light channel of a first image, and respectively restoring to a red light channel intermediate image and a green light channel intermediate image through a first deformation field; then, respectively substituting the exposure time corresponding to the first image into the red light channel relational expression and the green light channel relational expression to obtain the light intensity changes of the red light channel and the green light channel caused by reflection, namely the gray value correction of the red light channel and the gray value correction of the green light channel; subtracting the red light channel gray value correction quantity from the red light channel intermediate image to obtain a red light channel reference image, wherein the red light channel reference image is the radiation intensity value of the red light channel with the reflection light intensity removed; and subtracting the green light channel gray value correction quantity from the green light channel intermediate image gray value to obtain a green light channel reference image, wherein the green light channel reference image is the radiation intensity value of the green light channel with the reflection intensity removed, so that the reflection intensity doped in the brightness of the red light channel and the green light channel is eliminated, and the temperature field of the measured object is obtained based on a colorimetric thermometry according to the red light channel reference image, the green light channel reference image and the corresponding reference point temperature.
Exemplarily, a single-point infrared thermometer positioning laser can be started, and a temperature measurement position point (i.e. a reference point) of the infrared thermometer is determined and recorded; then, turning off the single-point infrared thermometer to position the laser; heating the surface of the object to be measured, adjusting the exposure time to ensure that the image shot is clear without overexposure, and recording the image P1Simultaneously recording the temperature value of the single-point temperature measuring instrument; analogizing in turn to obtain an experimental image sequence P1～PnExposure timeSequence Tt1～TtnReference point temperature sequence Te_1～Te_n(ii) a Selecting a first image P from the sequence of experimental imagesmWith a corresponding exposure time of TtmReference point temperature of Te_m(ii) a Extracting a first image PmRed light channel R ofmAnd green channel GmBy the above-mentioned deformation field (u)c,vc) R is to bemAnd GmRespectively restore to the red light channel intermediate image Rm_refAnd green channel intermediate image Gm_ref(ii) a Exposure time TtmRespectively substituted into the above-mentioned red light channel relational expression FRAnd green channel relation FGObtaining the correction value R of the gray value of the red light channelm_ref_FAnd green channel gray value correction Gm_ref_F(ii) a R is to bem_ref、Gm_ref、Rm_ref_F、Gm_ref_FSubstitution into Rm_real＝Rm_ref-Rm_ref_FAnd Gm_real＝Gm_ref-Gm_ref_FObtaining a red light channel reference image Rm_realAnd green channel reference image Gm_real(ii) a Then calculating the ratio of gray values of each pixel point of the red light channel and the green light channel at the moment
Figure BDA0002553230410000141
And the red channel grey value R of the reference pointm_real0And green channel gray value Gm_real0Ratio of
Figure BDA0002553230410000142
The full field temperature T is calculated based on the following formula:
Figure BDA0002553230410000143
wherein, C2Is the Planck constant, λR,λGCentral wavelengths, T, of the red and green channels, respectivelye_mIs the reference point temperature.
For example, the object to be measured is silicon carbide composite materialThe working process of dynamic measurement of temperature deformation under the environment is explained, wherein the texture of the silicon carbide surface is taken as speckle, and the size of the silicon carbide is 40mm multiplied by 5 mm. The heating adopts an oxygen propane flame heating mode to heat the back of the silicon carbide composite material, and an industrial CCD camera is adopted to shoot the front of the silicon carbide. The inner diameter of the flame nozzle is 2mm, the distance between the spray gun and the surface of the test piece is 4-5 cm, the air pressures of oxygen and propane are 0.5MPa and 0.1MPa respectively, the flow rates are 5L/min and 2L/min respectively, and the highest temperature of the oxy-propane flame can reach more than 1500K. The method comprises the following specific steps: 1) washing the surface of a silicon carbide sample to be detected by deionized water, wiping by a brush, and drying to remove impurities such as dust on the surface of the silicon carbide; 2) a blue light band-pass filter (band-pass parameter 435-; 3) connecting a blue light source to a computer, and turning on and aligning the silicon carbide; 4) turning off an ambient light source, turning on a blue light source and a camera, and adjusting the focal length of the camera to enable an image to be clear; setting the acquisition frame rate of a camera to be 5fps and setting the exposure time to be T0Adjusting the aperture to 200000us to ensure that the captured image does not have an overexposure phenomenon, namely the maximum gray value of the image does not exceed 65535, and fixing the camera aperture; 5) record the exposure time value T at this time0Taking an image of the surface of the silicon carbide surface, denoted as F0(ii) a 6) Presetting total adjustment times as 10 times, gradually reducing exposure time values to 180000us,160000us, …, 20000us and 0us, respectively shooting silicon carbide surface images under different exposure times to obtain F0～F10A sequence of images (i.e. a second sequence of images) comprising a total of 11 images; 7) extraction of F0～F10Traversing all pixel points by the gray values of the red light channel and the green light channel of the image sequence, and respectively fitting a reflection gray-exposure time function F to each pixel point by adopting a linear function formR、FG(i.e., the second relationship); 8) starting a single-point infrared thermometer to position laser, determining a temperature measurement position point (reference point) of the infrared thermometer and recording; then, turning off the single-point infrared thermometer to position the laser; 9) taking an image of the surface of silicon carbide as an initial image P of the experiment0(ii) a 10) To carbonizationHeating the back surface of the silicon, and collecting an image on the front surface after the state is stable; adjusting exposure time to ensure clear imaging of the shot image without overexposure, and recording the image as P1(i.e. the first image) and simultaneously recording the temperature value T of the single-point thermometer at the momente_1And exposure time Tt1(ii) a 11) Extraction of P0And P1Blue light channel gray scale image, respectively marked as B0And B1Calculating the deformation field (u) by using a digital image correlation method1,v1) (i.e., the second deformation field); 12) b is to be1By means of a deformation field (u)1,v1) Restore to blue channel intermediate image B1_ref_1Then B is1_ref_1And B0Compared with the method only comprising brightness change caused by high-temperature radiation; 13) intermediate image B of blue channel1_ref_1And an initial image B0Dividing the image into a plurality of sub-regions, wherein the size of each sub-region is 3 multiplied by 3 pixels, assuming that the brightness between the intermediate image of the blue light channel and the initial image is changed as an exponential function for each sub-region, fitting the brightness change relation (adopting the optimal square approximation) one by one to obtain a segmented continuous brightness change relation (namely a first light system formula) Li_ref_1(x, y), wherein x and y are coordinates of the pixel points, and i is the ordinal number of the subarea; 14) mixing L withi_ref_1(x, y) blue light channel gray-scale image B superimposed on initial image0Obtaining a new blue light channel reference image B only containing brightness change0_1(ii) a 15) Using B0_1And B1Calculating a new deformation field (u)2,v2) And circularly performing the steps 12) to 14) for 3 times to finally obtain the real full-field deformation (u)3,v3) (i.e., the first deformation field); 16) extracting a current image P1Respectively, denoted as R1、G1By means of a deformation field (u)3,v3) Restore to the red channel intermediate image R1_refAnd green channel intermediate image G1_ref(ii) a Exposure time Tt1Respectively substituted into the above FR、FGThe light intensity changes of the red light channel and the green light channel caused by reflection can be obtained, namely the correction value R of the gray value of the red light channel1_ref_FAnd green channel gray scale valueCorrection quantity G1_ref_F(ii) a 17) By means of R1_real＝R1_ref-R1_ref_FAnd G1_real＝G1_ref-G1_ref_FThe radiation intensity value R of the red light channel and the green light channel with the reflection removed can be obtained1_real,G1_real(ii) a 18) Calculating the ratio of gray values of each pixel point of the red light channel and the green light channel at the moment
Figure BDA0002553230410000151
And the ratio of the gray values of the red light channel and the green light channel of the reference point
Figure BDA0002553230410000161
The full field temperature T is calculated based on the following formula:
Figure BDA0002553230410000162
wherein, C2Is the Planck constant, λR,λGCentral wavelengths, T, of the red and green channels, respectivelye_1Is the reference point temperature.
It should be noted that, although the above embodiments are described as examples of the dynamic measurement method of temperature deformation in a high temperature environment, those skilled in the art can understand that the disclosure should not be limited thereto. In fact, the user can flexibly set each implementation mode according to personal preference and/or actual application scene, as long as the technical scheme of the disclosure is met.
In this way, in the embodiment of the disclosure, the initial image is corrected according to the brightness change relationship between the first image and each pixel point in the initial image, so that a deformation field of the measured object is obtained according to the corrected initial image and the first image; the first image can be corrected according to the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image and by combining the obtained first deformation field, and the temperature field of the measured object can be obtained according to the corrected first image and the temperature of the reference point; therefore, the influence of nonlinear brightness change caused by strong light radiation on deformation measurement and the influence of high-brightness reflection on radiation temperature measurement in a high-temperature environment are eliminated, and high-precision, dynamic, synchronous and online measurement of a single-camera deformation field and a temperature field is realized.
Fig. 7 shows a block diagram of a dynamic measurement device for temperature deformation according to an embodiment of the present disclosure. As shown in fig. 7, the apparatus may include: an image obtaining module 41, configured to obtain a first image of a surface of the object to be measured in a heating process and an initial image of the surface of the object to be measured when the object is not heated; a deformation field solving module 42, configured to correct the initial image according to a first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image; and the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image.
Fig. 8 shows a block diagram of a dynamic measurement device for temperature deformation according to an embodiment of the present disclosure. As shown in fig. 8, the apparatus may include: the image processing device comprises an image acquisition module 41, a deformation field solving module 42 and a temperature field solving module 43, wherein the temperature field solving module 43 is used for correcting the first image according to the first deformation field and the second relational expression; obtaining a temperature field of the measured object according to the corrected first image and the reference point temperature; the second relational expression represents the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image, and the reference point temperature is the single-point temperature of the surface of the measured object when the first image is shot.
In a possible implementation manner, the first relation represents a luminance variation relationship between the blue light channel of the first image and each pixel in the blue light channel of the initial image, and the apparatus further includes: the first relational module is used for obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image; removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image; and fitting the brightness difference of each pixel point of the blue light channel in the blue light channel intermediate image and the initial image to obtain the first relational expression.
In one possible implementation, the deformation field obtaining module 42 is specifically configured to: determining the brightness correction quantity of each pixel point in the initial image according to the first relational expression; correcting the blue light channel of the initial image through the brightness correction amount of each pixel point to obtain a blue light channel reference image; and obtaining the first deformation field according to the blue light channel reference image and the gray value of the blue light channel of the first image.
In one possible implementation, the second relation includes: a red light channel relation and a green light channel relation; the device further comprises: the second relational expression module is used for acquiring a second image sequence of the surface of the measured object, which is shot under different exposure times when the measured object is not heated; extracting a red light channel and a green light channel of the second image sequence; and fitting the gray values of the pixel points in the red light channel and the green light channel and the corresponding exposure time to obtain the red light channel relational expression and the green light channel relational expression.
In a possible implementation manner, the temperature field obtaining module 43 is specifically configured to: respectively removing displacement values in a red light channel and a green light channel of the first image according to the first deformation field to obtain a red light channel intermediate image and a green light channel intermediate image; determining a red light channel gray value correction amount and a green light channel gray value correction amount according to the exposure time for shooting the first image, the red light channel relational expression and the green light channel relational expression; correcting the gray value of the intermediate image of the red light channel through the gray value correction quantity of the red light channel to obtain a reference image of the red light channel; correcting the gray value of the green light channel intermediate image through the green light channel gray value correction quantity to obtain a green light channel reference image; and obtaining the temperature field of the measured object according to the red light channel reference image, the green light channel reference image and the reference point temperature.
In one possible implementation, the deformation field obtaining module 42 is specifically configured to: obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image; removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image; fitting the brightness difference of each pixel point in the blue light channel of the intermediate image of the blue light channel and the initial image to obtain the first relational expression; correcting the initial image according to the first image and the first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image; and repeatedly executing the operations of obtaining the intermediate image of the blue light channel and the subsequent operations according to the obtained first deformation field and the blue light channel of the first image until a preset iteration condition is met.
It should be noted that, although the above embodiments are described as examples of the dynamic temperature deformation measuring device in a high temperature environment, those skilled in the art can understand that the disclosure should not be limited thereto. In fact, the user can flexibly set each implementation mode according to personal preference and/or actual application scene, as long as the technical scheme of the disclosure is met.
In this way, in the embodiment of the disclosure, the initial image is corrected according to the brightness change relationship between the first image and each pixel point in the initial image, so that a deformation field of the measured object is obtained according to the corrected initial image and the first image; the first image can be corrected according to the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image and by combining the obtained first deformation field, and the temperature field of the measured object can be obtained according to the corrected first image and the temperature of the reference point; therefore, the influence of nonlinear brightness change caused by strong light radiation on deformation measurement and the influence of high-brightness reflection on radiation temperature measurement in a high-temperature environment are eliminated, and high-precision, dynamic, synchronous and online measurement of a single-camera deformation field and a temperature field is realized.
The embodiment of the present disclosure further provides a temperature deformation dynamic measurement apparatus, including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to perform the above method.
The disclosed embodiments also provide a non-transitory computer-readable storage medium having stored thereon computer program instructions, wherein the computer program instructions, when executed by a processor, implement the above-described method.
Fig. 9 shows a block diagram for a temperature deformation dynamic measurement device 1900 according to an embodiment of the present disclosure. For example, the apparatus 1900 may be provided as a server or terminal device. Referring to fig. 9, the device 1900 includes a processing component 1922 further including one or more processors and memory resources, represented by memory 1932, for storing instructions, e.g., applications, executable by the processing component 1922. The application programs stored in memory 1932 may include one or more modules that each correspond to a set of instructions. Further, the processing component 1922 is configured to execute instructions to perform the above-described method.
The device 1900 may also include a power component 1926 configured to perform power management of the device 1900, a wired or wireless network interface 1950 configured to connect the device 1900 to a network, and an input/output (I/O) interface 1958. The device 1900 may operate based on an operating system stored in memory 1932, such as Windows Server, Mac OS XTM, UnixTM, LinuxTM, FreeBSDTM, or the like.
In an exemplary embodiment, a non-transitory computer readable storage medium, such as the memory 1932, is also provided that includes computer program instructions executable by the processing component 1922 of the apparatus 1900 to perform the above-described methods.
The present disclosure may be systems, methods, and/or computer program products. The computer program product may include a computer-readable storage medium having computer-readable program instructions embodied thereon for causing a processor to implement various aspects of the present disclosure.
The computer readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or electrical signals transmitted through electrical wires.
The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device via a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.
The computer program instructions for carrying out operations of the present disclosure may be assembler instructions, Instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, the electronic circuitry that can execute the computer-readable program instructions implements aspects of the present disclosure by utilizing the state information of the computer-readable program instructions to personalize the electronic circuitry, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA).
Various aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.
These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer-readable medium storing the instructions comprises an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (7)

1. A method for dynamically measuring temperature distortion, comprising:
acquiring a first image of the surface of a measured object in a heating process and an initial image of the surface of the measured object when the surface is not heated;
correcting the initial image according to a first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image;
the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image;
correcting the first image according to the first deformation field and a second relational expression; obtaining a temperature field of the measured object according to the corrected first image and the reference point temperature;
the second relational expression represents the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image, and the reference point temperature is the single-point temperature of the surface of the measured object when the first image is shot;
the second relation includes: a red light channel relation and a green light channel relation;
the method further comprises the following steps:
acquiring a second image sequence of the surface of the measured object, which is shot under different exposure times when the measured object is not heated;
extracting a red light channel and a green light channel of the second image sequence;
fitting gray values of all pixel points in the red light channel and the green light channel and corresponding exposure time to obtain a red light channel relational expression and a green light channel relational expression;
correcting the first image according to the first deformation field and a second relational expression; and according to the corrected first image and the reference point temperature, obtaining the temperature field of the measured object, including:
respectively removing displacement values in a red light channel and a green light channel of the first image according to the first deformation field to obtain a red light channel intermediate image and a green light channel intermediate image;
determining a red light channel gray value correction amount and a green light channel gray value correction amount according to the exposure time for shooting the first image, the red light channel relational expression and the green light channel relational expression;
correcting the gray value of the intermediate image of the red light channel through the gray value correction quantity of the red light channel to obtain a reference image of the red light channel;
correcting the gray value of the green light channel intermediate image through the green light channel gray value correction quantity to obtain a green light channel reference image;
and obtaining the temperature field of the measured object according to the red light channel reference image, the green light channel reference image and the reference point temperature.
2. The method of claim 1, wherein the first relation represents a luminance variation relationship between each pixel in the blue channel of the first image and the blue channel of the initial image, and the method further comprises:
obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image;
removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image;
and fitting the brightness difference of each pixel point of the blue light channel in the blue light channel intermediate image and the initial image to obtain the first relational expression.
3. The method according to any of claims 1-2, wherein the initial image is modified according to a first relation; and according to the corrected initial image and the first image, obtaining a first deformation field of the measured object, comprising:
determining the brightness correction quantity of each pixel point in the initial image according to the first relational expression;
correcting the blue light channel of the initial image through the brightness correction amount of each pixel point to obtain a blue light channel reference image;
and obtaining the first deformation field according to the blue light channel reference image and the gray value of the blue light channel of the first image.
4. The method of claim 1, wherein the initial image is modified according to a first relationship; and according to the corrected initial image and the first image, obtaining a first deformation field of the measured object, comprising:
obtaining a second deformation field of the object to be measured according to the gray value of the blue light channel in the first image and the gray value of the blue light channel in the initial image;
removing the displacement value in the blue light channel of the first image according to the second deformation field to obtain a blue light channel intermediate image;
fitting the brightness difference of each pixel point in the blue light channel of the intermediate image of the blue light channel and the initial image to obtain the first relational expression;
correcting the initial image according to the first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image;
and repeatedly executing the operations of obtaining the intermediate image of the blue light channel and the subsequent operations according to the obtained first deformation field and the blue light channel of the first image until a preset iteration condition is met.
5. A dynamic temperature deformation measuring device, comprising:
the image acquisition module is used for acquiring a first image of the surface of the object to be measured in the heating process and an initial image of the surface of the object to be measured in the unheated process;
the deformation field obtaining module is used for correcting the initial image according to a first relational expression; obtaining a first deformation field of the measured object according to the corrected initial image and the first image;
the first relational expression represents the brightness change relation between the first image and each pixel point in the initial image;
the image processing device is also used for correcting the first image according to the first deformation field and the second relational expression; obtaining a temperature field of the measured object according to the corrected first image and the reference point temperature;
the second relational expression represents the relation between the intensity of the reflected light of each pixel point in the first image and the exposure time for shooting the first image, and the reference point temperature is the single-point temperature of the surface of the measured object when the first image is shot;
the second relation includes: a red light channel relation and a green light channel relation;
the device further comprises: the second relational expression module is used for acquiring a second image sequence of the surface of the measured object, which is shot under different exposure times when the measured object is not heated; extracting a red light channel and a green light channel of the second image sequence; fitting gray values of all pixel points in the red light channel and the green light channel and corresponding exposure time to obtain a red light channel relational expression and a green light channel relational expression;
correcting the first image according to the first deformation field and a second relational expression; and according to the corrected first image and the reference point temperature, obtaining the temperature field of the measured object, including:
respectively removing displacement values in a red light channel and a green light channel of the first image according to the first deformation field to obtain a red light channel intermediate image and a green light channel intermediate image;
determining a red light channel gray value correction amount and a green light channel gray value correction amount according to the exposure time for shooting the first image, the red light channel relational expression and the green light channel relational expression;
correcting the gray value of the intermediate image of the red light channel through the gray value correction quantity of the red light channel to obtain a reference image of the red light channel;
correcting the gray value of the green light channel intermediate image through the green light channel gray value correction quantity to obtain a green light channel reference image;
and obtaining the temperature field of the measured object according to the red light channel reference image, the green light channel reference image and the reference point temperature.
6. A dynamic temperature deformation measuring device, comprising:
a processor;
a memory for storing processor-executable instructions;
wherein the processor is configured to implement the method of any one of claim 1 to claim 4 when executing the memory-stored executable instructions.
7. A non-transitory computer readable storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by a processor, implement the method of any of claims 1 to 4.
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