Method for reconstructing three-dimensional temperature field of solid surface based on phosphorescence excited by striped ultraviolet light

Abstract

The present application relates to non-contact temperature measurement technology, and aims to provide a solid surface three-dimensional temperature field reconstruction method based on stripe ultraviolet light excited phosphor. The method comprises the following steps: using an optical element to expand the ultraviolet laser into stripe light with light and dark interbedded, and projecting the stripe light on the measured solid surface; using the stripe ultraviolet light to excite the phosphor coating coated on the measured solid surface, and inducing the phosphor coating to generate stripe phosphor signal; using a digital image acquisition device to acquire the phosphor signal images under different characteristic wavelengths, and based on the temperature sensitivity of the phosphor signal and the stereoscopic geometric information contained in the stripe phase distribution, the measurement and reconstruction of the solid surface three-dimensional temperature field are carried out. The present application can complete the measurement and reconstruction of the solid surface three-dimensional temperature field only by using a single light source and a digital image acquisition device based on the temperature sensitivity of the phosphor signal and the stereoscopic geometric information contained in the stripe phase distribution; the system is simple and the reconstruction is convenient, and the real temperature condition of the three-dimensional solid surface can be reflected.

Description

Technical Field

[0001] This invention relates to non-contact temperature measurement technology, and in particular to a method for reconstructing the three-dimensional temperature field of a solid surface based on striped ultraviolet light-excited phosphorescence. Background Technology

[0002] Three-dimensional temperature field data of solid surfaces are crucial for the safety design and performance evaluation of various components. Methods for measuring solid surface temperature can be divided into contact and non-contact methods. Contact methods, represented by thermocouples, require contact with the target object, thus disrupting its thermal equilibrium, exhibiting poor dynamic performance and slow response, making them unsuitable for accurate real-time temperature measurement. Non-contact methods, on the other hand, do not require contact with the target object, thus avoiding interference with its temperature field, and offer fast response, making them suitable for measuring surface temperatures in high-temperature and complex environments. Commonly used non-contact methods include radiation thermometry and laser-induced phosphorescence (LIP) and other optical thermometry methods.

[0003] Radiation thermometry is widely used in engineering projects such as high-temperature testing of typical engine hot-end components. However, due to the unknown emissivity of the object surface and the interference of background thermal radiation, it is difficult to achieve high-precision temperature measurement under complex thermal environments.

[0004] In recent years, the rapid development of laser technology has led to the gradual emergence of temperature field measurement techniques based on laser spectroscopy. Laser-induced phosphorescence thermometry is a non-contact optical thermometry technique that measures temperature based on the temperature-sensitive phosphorescent signal generated by the excitation of a phosphorescent coating on a target surface. By spraying a phosphorescent material onto the surface of the target and exciting it with ultraviolet light to cause electrons to transition from the ground state to a higher energy state, the photons emitted when the electrons return from the higher energy state to the ground state are phosphorescence. The luminescence lifetime or characteristic spectral intensity ratio of phosphorescence is temperature-sensitive; therefore, by calibrating and obtaining the mathematical relationship between the phosphorescence characteristic spectral intensity ratio or lifetime and temperature, solid surface temperature field measurements can be performed. Since the phosphorescence signal is independent of the material properties of the target surface and has multiple characteristic emission wavelengths, laser-induced phosphorescence thermometry can avoid interference from the unknown emissivity of the target and background thermal radiation, offering advantages such as high measurement accuracy, fast response, and a wide temperature range.

[0005] However, current methods of radiation thermometry or laser-induced phosphorescence thermometry generally use modulated surface light sources for laser irradiation, resulting in only two-dimensional temperature field data after measurement and reconstruction. Therefore, current testing methods are typically limited to two-dimensional planar products. For three-dimensional products (especially those with irregular shapes), current radiation thermometry or laser-induced phosphorescence thermometry methods cannot reconstruct the three-dimensional temperature field of the target surface. If two-dimensional temperature field data is forcibly used for simulation calculations, the large calculation deviations will lead to significant differences between the temperature field data and the actual temperature of the object's surface, failing to meet application requirements.

[0006] Therefore, it is necessary to propose new solutions to enable the measurement and reconstruction of the temperature field on a three-dimensional solid surface. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem that existing technologies are difficult to reconstruct the target three-dimensional temperature field, and to provide a method for reconstructing the three-dimensional temperature field of a solid surface based on striped ultraviolet light-excited phosphorescence.

[0008] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0009] A method for reconstructing the three-dimensional temperature field of a solid surface based on striped ultraviolet light-induced phosphorescence is provided. This method utilizes optical elements to expand ultraviolet laser light into alternating bright and dark stripes, which are then projected onto the solid surface to be measured, which has a three-dimensional shape. The striped ultraviolet light excites a phosphorescent coating on the solid surface, inducing the generation of striped phosphorescent signals. A digital image acquisition device is used to acquire phosphorescent signal images at different characteristic wavelengths. Based on the temperature sensitivity of the phosphorescent signals and the three-dimensional geometric information contained in the stripe phase distribution, the three-dimensional temperature field of the solid surface is measured and reconstructed.

[0010] As a preferred embodiment of the present invention, the method for reconstructing the three-dimensional temperature field of a solid surface in a static state specifically includes the following steps:

[0011] (1) Place the calibration plate with a phosphorescent coating on its surface into the inner cavity of the blackbody furnace, and set an optical window on the furnace wall;

[0012] (2) The ultraviolet laser is controlled by a timing synchronization controller to emit ultraviolet laser. The wavelength of the laser is matched with the excitation characteristics of the phosphorescent material contained in the phosphorescent coating. The laser passes through the optical path composed of a beam expander, a grating, a plano-convex spherical lens, a spatial filter and an aperture in sequence. Due to interference, it generates alternating bright and dark sinusoidal ultraviolet light. Then, the sinusoidal ultraviolet light is irradiated onto the phosphorescent coating of the calibration plate to excite the phosphorescent material to produce striped phosphorescent signals.

[0013] (3) Using two digital image acquisition devices equipped with narrowband filters, phosphorescent signal images of different characteristic wavelengths are acquired simultaneously through dichroic mirrors, and the coordinates on the two images are kept in correspondence.

[0014] (4) Adjust the temperature of the blackbody furnace within a certain temperature range at set temperature intervals, record phosphorescent signal images with a digital image acquisition device and transmit them to a computer for processing: calculate the ratio of the average signal intensities I1 and I2 of two stripe phosphorescent images G1 and G2 with different characteristic wavelengths obtained simultaneously at each temperature T, and obtain the ratio of the stripe phosphorescent signal intensities of the two characteristic wavelengths at that temperature, R = I1 / I2; complete the processing of all temperature-adjusted sampling signals, obtain the response curve f(R,T) of the phosphorescent signal ratio R with temperature T, and complete the temperature curve calibration;

[0015] (5) Replace the calibration board described in step (1) with a checkerboard calibration board to calibrate the internal and external parameters of the two digital image acquisition devices; on this basis, use the reverse camera calibration method or the pseudo camera calibration method to calibrate the internal and external parameters of the ultraviolet continuous laser used.

[0016] (6) Referring to the calibration plate described in step (1), a phosphorescent coating is prepared on the surface of the solid to be tested; the checkerboard calibration plate in step (5) is replaced in situ with the solid to be tested, and the solid to be tested is placed in an actual thermal environment; sinusoidal striped ultraviolet light is irradiated onto the surface of the solid to be tested using an ultraviolet continuous laser and optical elements; the stripe frequency f1 = 10 of the ultraviolet light is kept fixed, but the stripe phase is uniformly and successively shifted by 2π / 3 from the initial state, thereby forming multiple different phosphorescent signal patterns on the surface of the solid to be tested, and phosphorescent signal images at two wavelengths are acquired simultaneously using two digital image acquisition devices; then, the stripe frequency is changed to f2 = 20 and f3 = 40, and the above irradiation and acquisition process is repeated;

[0017] (7) Select the wavelength corresponding to any narrowband filter, and use the standard N-step phase shift algorithm to perform stripe analysis on the phosphorescent signal pattern at each stripe frequency to obtain three sets of truncated phase distribution data of the solid surface under test at different frequencies; use the three-frequency heterodyne method to perform phase expansion and restore the obtained truncated phase to a continuous phase distribution.

[0018] (8) Based on the internal and external parameters of the digital image acquisition device and the ultraviolet continuous laser calibrated in step (5), and the continuous phase distribution of the solid surface to be measured obtained in step (7), construct a model of the relationship between the phase distribution of the solid to be measured and the three-dimensional coordinates in combination with the triangulation principle, and calculate the three-dimensional spatial coordinates of the solid to be measured.

[0019] (9) Calculate the ratio of the three sets of phosphorescent signals with different stripe frequencies obtained in step (6) at two wavelengths point by point to obtain the intensity ratio of the three sets of phosphorescent signals, and calculate the stripe temperature field information according to the temperature calibration curve f(R,T); splice and interpolate the three sets of stripe interval temperature field information to obtain the continuous two-dimensional temperature field distribution of the solid surface under test.

[0020] (10) Match the three-dimensional coordinates of the solid under test with the continuous two-dimensional temperature field distribution on the surface point by point according to the spatial correspondence, and reconstruct the three-dimensional temperature field of the solid under test in a static state.

[0021] As a preferred embodiment of the present invention, the phosphorescent material Y3Al5O 12 Dy and high-temperature adhesive are mixed in an appropriate ratio to prepare a phosphorescent material spray, which is then sprayed onto the surface of the calibration plate and the solid being tested to form a phosphorescent coating; the laser wavelength emitted by the ultraviolet continuous laser is 355nm, and the center wavelengths of the two narrowband filters are 457nm and 490nm, respectively.

[0022] As a preferred embodiment of the present invention, the method for reconstructing the three-dimensional temperature field of a solid surface in motion specifically includes the following steps:

[0023] (1) Place the calibration plate with a phosphorescent coating on its surface into the inner cavity of the blackbody furnace, and set an optical window on the furnace wall;

[0024] (2) The ultraviolet pulse laser is controlled by a timing synchronization controller to emit ultraviolet laser. The wavelength of the laser is matched with the excitation characteristics of the phosphorescent material contained in the phosphorescent coating. The laser passes through the optical path composed of a beam expander, a grating, a plano-convex spherical lens, a spatial filter and an aperture in sequence. Due to interference, it generates alternating bright and dark sinusoidal ultraviolet light. Then, the sinusoidal ultraviolet light is irradiated onto the phosphorescent coating of the calibration plate to excite the phosphorescent material to produce striped phosphorescent signals.

[0025] (3) A stereo lens is installed at the front end of the digital image acquisition device, and two narrowband filters of different wavelengths are installed in front of the stereo lens; phosphorescent signal images of different characteristic wavelengths are acquired at the same time, and the coordinates on the two images are kept in correspondence.

[0026] (4) Adjust the temperature of the blackbody furnace within a certain temperature range at set temperature intervals, record phosphorescent signal images with a digital image acquisition device and transmit them to a computer for processing: calculate the ratio of the average signal intensities I1 and I2 of two stripe phosphorescent images G1 and G2 with different characteristic wavelengths obtained simultaneously at each temperature T, and obtain the ratio of the stripe phosphorescent signal intensities of the two characteristic wavelengths at that temperature, R = I1 / I2; complete the processing of all temperature-adjusted sampling signals, obtain the response curve f(R,T) of the phosphorescent signal ratio R with temperature T, and complete the temperature curve calibration;

[0027] (5) Replace the calibration plate described in step (1) with a checkerboard calibration plate to calibrate the internal and external parameters of the digital image acquisition device; on this basis, use the reverse camera calibration method or the pseudo camera calibration method to calibrate the internal and external parameters of the ultraviolet pulse laser used.

[0028] (6) Referring to the calibration plate described in step (1), a phosphorescent coating is prepared on the surface of the solid to be tested; the checkerboard calibration plate in step (5) is replaced in situ with the solid to be tested, and the solid to be tested is placed in an actual thermal environment; sinusoidal ultraviolet light is irradiated onto the surface of the solid to be tested using an ultraviolet pulse laser and optical elements; the stripe frequency of the ultraviolet light is kept fixed and there is no phase shift, and the phosphorescent signal images generated by the surface of the solid to be tested under two wavelengths are acquired simultaneously using a digital image acquisition device;

[0029] (7) Select any wavelength corresponding to a narrowband filter, and use the Fourier transform contour method to perform stripe analysis on a single phosphorescent signal image to obtain the truncated phase distribution data of the dynamic solid under test; use the spatial phase unfolding algorithm to unfold the phase and restore the obtained truncated phase to a continuous phase distribution.

[0030] (8) Based on the internal and external parameters of the digital image acquisition device and the ultraviolet pulse laser calibrated in step (5), and the continuous phase distribution of the solid surface to be measured obtained in step (7), construct the phase distribution and three-dimensional coordinate relationship model of the solid to be measured in combination with the triangulation principle, and calculate the three-dimensional coordinates of the dynamic three-dimensional component to be measured.

[0031] (9) Calculate the ratio of the phosphorescent signal intensity at each of the two wavelengths obtained in step (6) to obtain the phosphorescent signal intensity ratio, and calculate the temperature field information of the stripe interval according to the temperature calibration curve f(R,T); perform interpolation processing on the temperature field information of the stripe interval to obtain the continuous two-dimensional temperature field distribution of the solid surface under test.

[0032] (10) Based on the spatial correspondence, the three-dimensional spatial coordinates of the solid under test are matched point by point with the continuous two-dimensional temperature field of the surface to reconstruct the three-dimensional temperature field of the solid under test under dynamic conditions.

[0033] As a preferred embodiment of the present invention, the phosphorescent material BaMgAl 10 O 17 Eu and high-temperature adhesive are mixed in an appropriate ratio to prepare a phosphorescent material spray, which is then sprayed onto the surface of the calibration plate and the solid being tested to form a phosphorescent coating; the ultraviolet pulsed laser emits a laser wavelength of 355nm, and the center wavelengths of the two narrowband filters are 400nm and 456nm, respectively.

[0034] As a preferred embodiment of the present invention, in step (4), the temperature adjustment range of the blackbody furnace is 400 to 1400°C, and the temperature adjustment interval is 10°C.

[0035] As a preferred embodiment of the present invention, in step (5), the intrinsic parameters refer to the focal length, principal point, and distortion of the digital image acquisition device; the extrinsic parameters refer to the posture characteristics of the digital image acquisition device relative to the object, including rotation vector and translation vector.

[0036] This invention further provides a measurement system for the three-dimensional temperature field of a solid surface based on phosphorescence excited by striped ultraviolet light. An ultraviolet laser, optical elements, and a blackbody furnace are arranged sequentially along the optical path, with a digital image acquisition device positioned on the side of the optical path. The ultraviolet laser and the digital image acquisition device are connected to a timing synchronization controller via signal lines, and a computer is connected to the digital image acquisition device via a signal line. The blackbody furnace is hollow inside, with optical windows on its walls. A calibration plate with a phosphorescent coating, a checkerboard calibration plate, or a solid to be measured with a phosphorescent coating is placed inside the furnace cavity. The optical elements comprise an optical path consisting of a beam expander, a grating, a plano-convex spherical lens, a spatial filter, and an aperture arranged sequentially. This optical path is capable of generating alternating bright and dark sinusoidal striped ultraviolet light based on interference, and the light is transmitted through the optical windows. The image is projected onto the surface of the object inside the furnace cavity. Depending on the static and dynamic measurement scenarios, different numbers of digital image acquisition devices are used: for measuring a stationary solid, two digital image acquisition devices are used, each with a narrowband filter of different center wavelengths installed in front of its lens, and a dichroic mirror is placed between the digital image acquisition device and the optical window; for measuring a moving solid, one digital image acquisition device is used, with a stereo lens mounted in front of its lens, and two narrowband filters of different center wavelengths installed in front of the stereo lens. The measurement system also includes a calibration plate with phosphorescent coating, a checkerboard calibration plate, and a solid to be measured with phosphorescent coating, which are placed inside the blackbody furnace cavity according to the measurement steps.

[0037] As a preferred embodiment of the present invention, the ultraviolet laser is a pulsed laser or a continuous laser, and the laser energy is adjustable.

[0038] As a preferred embodiment of the present invention, the digital image acquisition device is a CCD camera, an enhanced CCD camera (ICCD camera), a CMOS camera, or an enhanced CMOS camera.

[0039] In this invention, the generation process of sinusoidal ultraviolet light is as follows: First, a beam expander is used to expand the ultraviolet laser beam into a parallel beam with the required beam diameter. Second, a grating is used to split the parallel beam. Then, two coherent beams are obtained by filtering with a plano-convex spherical lens and a spatial filter. Finally, interference is used to generate alternating bright and dark ultraviolet sinusoidal stripe light, and stray light is filtered out with the help of an aperture.

[0040] For dynamic measurements, due to the shorter exposure time, enhanced CCD cameras (ICCD cameras) or enhanced CMOS cameras are typically used. However, if the signal intensity of the sinusoidal ultraviolet light is high enough, even in dynamic measurements, ordinary CCD or CMOS cameras can be used, depending on the specific circumstances.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] Compared with existing optical temperature measurement technologies such as radiation thermometry or laser-induced phosphorescence thermometry, this invention utilizes alternating bright and dark sinusoidal ultraviolet light to excite the phosphorescent coating on the solid surface to generate striped phosphorescent signals. Therefore, based on the temperature sensitivity of the phosphorescent signal and the three-dimensional geometric information contained in the stripe phase distribution, the three-dimensional temperature field of the solid surface can be measured and reconstructed using only a single light source and a digital image acquisition device. The system is simple and easy to reconstruct, and can well reflect the true temperature of the three-dimensional solid surface. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the device for measuring and reconstructing the three-dimensional temperature field of a static solid surface as described in Embodiment 1 of the present invention;

[0044] Figure 2 This is a schematic diagram of the device for measuring and reconstructing the three-dimensional temperature field of a dynamic solid surface as described in Embodiment 2 of the present invention.

[0045] The figures are labeled as follows: 1. Calibration plate; 2. Blackbody furnace (the furnace is used for calibration, but the actual thermal environment is used for measurement and reconstruction); 3. Ultraviolet continuous laser; 4. Timing synchronization controller; 5. Beam expander; 6. Grating; 7. Plano-convex spherical lens; 8. Spatial filter; 9. Aperture; 10. CCD camera one; 11. CCD camera two; 12. Dichroic mirror; 13. Computer; 14. Checkerboard calibration plate; 15. The solid component to be measured; 16. Ultraviolet pulsed laser; 17. ICCD camera; 18. Stereo lens; 19. The dynamic solid component to be measured. Detailed Implementation

[0046] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all of them. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and all such modifications and improvements should fall within the protection scope of the present invention.

[0047] Example 1

[0048] Embodiment 1 of the present invention provides a method and apparatus for measuring and reconstructing the three-dimensional temperature field of a static solid surface based on striped phosphorescence, wherein the specific apparatus for measurement and reconstruction is shown in the attached figure. Figure 1 As shown, the specific method is as follows:

[0049] (1) Phosphorescent material Y3Al5O 12 Dy and high-temperature adhesive are mixed in a certain proportion to prepare phosphorescent material spray, which is sprayed onto the surface of calibration plate 1 to form a phosphorescent coating. The calibration plate is then placed in the inner cavity of blackbody furnace 2, which has an optical window on the furnace wall.

[0050] (2) The ultraviolet continuous laser 3 emits ultraviolet laser with a wavelength of 355nm under the action of the timing synchronization controller 4. A beam expander 5 composed of concave lens and convex lens, grating 6, plano-convex spherical lens 7, spatial filter 8 and aperture 9 are arranged in sequence in the optical path. Through interference, the light and dark ultraviolet sinusoidal stripe light is generated and irradiated on the phosphorescent coating of the calibration plate to excite the generation of stripe phosphorescent signal.

[0051] (3) Install CCD camera 10, CCD camera 2 11, and dichroic mirror 12 as attached Figure 1 The two cameras are arranged as shown, and narrowband filters with center wavelengths of 457nm and 490nm are installed in front of the lenses of the two cameras respectively, so as to achieve simultaneous acquisition of phosphorescent signal images of two characteristic wavelengths, and the coordinates of the two images correspond one-to-one.

[0052] (4) The temperature of the blackbody furnace 2 is changed in 10℃ intervals within the range of 400-1400℃. Two CCD cameras record the stripe phosphorescence signal images at each temperature and transmit them to the computer 13 for processing. The average signal intensities I1 and I2 of the two stripe phosphorescence images G1 and G2 with different characteristic wavelengths obtained at each temperature T are calculated to obtain the stripe phosphorescence signal intensity ratio R = I1 / I2 at that temperature. The signal processing at all temperatures is completed to obtain the response curve f(R,T) of the phosphorescence signal ratio R with temperature T and complete the temperature curve calibration.

[0053] (5) Replace the calibration board described in step (1) with a checkerboard calibration board 14 to calibrate the intrinsic parameters (focal length, principal point and distortion, etc.) and extrinsic parameters (camera attitude characteristics relative to the object, including rotation and translation vectors) of the two CCD cameras used in step (3); on this basis, use the reverse camera calibration method or the pseudo camera calibration method to calibrate the intrinsic and extrinsic parameters of the ultraviolet continuous laser 3 used in step (2);

[0054] (6) The phosphorescent material spray prepared in step (1) is sprayed onto the surface of the three-dimensional component 15 to be tested to form a phosphorescent coating. Then, the checkerboard calibration plate is replaced with it in situ and placed in an actual thermal environment. The ultraviolet continuous laser 3 and the optical elements described in step (2) are used to irradiate three ultraviolet stripe patterns onto the surface of the three-dimensional component to be tested. The stripe frequency f1 = 10 is fixed in each pattern, but the stripe phase is uniformly shifted by 2π / 3 from the initial state. For each irradiated ultraviolet stripe pattern, CCD camera 10 and CCD camera 21 are used to simultaneously acquire stripe phosphorescent signal images generated on the surface of the three-dimensional component to be tested at two wavelengths of 457nm and 490nm. The stripe frequency is changed to f2 = 20 and f3 = 40 and the above irradiation and acquisition process is repeated.

[0055] (7) Select the wavelength corresponding to any narrowband filter, and use the standard N-step phase shift algorithm to perform stripe analysis on the stripe phosphorescence image at each stripe frequency to obtain three sets of truncated phase distribution data of the solid under test at different frequencies; use the three-frequency heterodyne method to perform phase expansion and restore the obtained truncated phase to a continuous phase distribution.

[0056] (8) Based on the internal and external parameters of CCD camera 10, CCD camera 21 and ultraviolet continuous laser 3 calibrated in step (5) and the continuous phase distribution of the solid surface measured in step (7), construct a model of the relationship between the phase distribution of the solid and the three-dimensional coordinates in the three-dimensional space of the solid, and calculate the three-dimensional spatial coordinates of the solid.

[0057] (9) Calculate the ratio of the three sets of stripe phosphorescent signals with different frequencies obtained in step (6) at two wavelengths point by point to obtain the intensity ratio of the three sets of stripe phosphorescent signals, and calculate the stripe temperature field information according to the temperature calibration curve f(R,T); splice and interpolate the three sets of stripe interval temperature field information to obtain the continuous two-dimensional temperature field distribution of the solid surface under test.

[0058] (10) Match the three-dimensional coordinates of the three-dimensional component with the two-dimensional temperature field of the surface point by point according to the spatial correspondence, and reconstruct the three-dimensional temperature field of the three-dimensional component.

[0059] Example 2

[0060] Embodiment 2 of the present invention provides a method and apparatus for measuring and reconstructing the three-dimensional temperature field of a dynamic solid surface based on striped phosphorescence, wherein the specific apparatus for measurement and reconstruction is shown in the attached figure. Figure 2 As shown, the specific method is as follows:

[0061] (1) Phosphorescent material BaMgAl 10 O 17Eu and high-temperature adhesive are mixed in a certain proportion to prepare phosphorescent material spray, which is sprayed onto the surface of calibration plate 1 to form a phosphorescent coating. The calibration plate is then placed in the inner cavity of blackbody furnace 2, which has an optical window on the furnace wall.

[0062] (2) The ultraviolet pulsed laser 16 emits ultraviolet laser with a wavelength of 355nm under the action of the timing synchronization controller 4. A beam expander 5 composed of a concave lens and a convex lens, a grating 6, a plano-convex spherical lens 7, a spatial filter 8 and an aperture 9 are arranged in sequence in the optical path. Through interference, the light and dark ultraviolet sinusoidal stripe light is generated and irradiated on the phosphorescent coating of the calibration plate to excite the generation of stripe phosphorescent signal.

[0063] (3) A stereo lens 18 is mounted on the front end of the ICCD camera 17, and narrowband filters with center wavelengths of 400nm and 456nm are added in front of the lens to achieve simultaneous acquisition of phosphorescent signal images of two characteristic wavelengths, and the coordinates of the two images correspond one-to-one.

[0064] (4) The temperature of the blackbody furnace 2 is changed in 10℃ intervals within the range of 400-1400℃. The stripe phosphorescence signal image at each temperature is recorded by the ICCD camera 17 and transmitted to the computer 13 for processing. The ratio of the average signal intensities I1 and I2 of the two stripe phosphorescence images G1 and G2 with different characteristic wavelengths obtained at each temperature T is calculated to obtain the stripe phosphorescence signal intensity ratio R = I1 / I2 at that temperature. The signal processing at all temperatures is completed to obtain the response curve f(R,T) of the phosphorescence signal ratio R with temperature T, and the temperature curve calibration is completed.

[0065] (5) Replace the calibration plate described in step (1) with a checkerboard calibration plate 14, and calibrate the intrinsic parameters (focal length, principal point and distortion, etc.) and extrinsic parameters (camera attitude characteristics relative to the object, including rotation and translation vectors) of the ICCD camera 17 used in step (3); on this basis, use the reverse camera calibration method or the pseudo camera calibration method to calibrate the intrinsic and extrinsic parameters of the ultraviolet pulse laser 16 used in step (2);

[0066] (6) Spray the phosphorescent material spray prepared in step (1) onto the surface of the dynamic three-dimensional component 19 to be tested to form a phosphorescent coating, and then replace the checkerboard calibration plate in situ and place it in an actual thermal environment; use the ultraviolet pulse laser 16 and the optical elements described in step (2) to irradiate the surface of the dynamic three-dimensional component 19 to be tested with a fixed stripe frequency and no phase shift, and use an ICCD camera 17 to simultaneously acquire the stripe phosphorescent signal images generated on the surface of the dynamic three-dimensional component 19 to be tested at two wavelengths of 400nm and 456nm;

[0067] (7) Select any wavelength and use the Fourier transform profile method to perform stripe analysis on a single stripe phosphorescence image to obtain the truncated phase distribution data of the solid under test; use the spatial phase unfolding algorithm to unfold the phase and restore the obtained truncated phase to a continuous phase distribution.

[0068] (8) Based on the internal and external parameters of the ICCD camera 17 and the ultraviolet pulse laser 16 calibrated in step (5) and the continuous phase distribution of the solid surface measured in step (7), construct a model of the relationship between the phase distribution of the solid and the three-dimensional coordinates in the three-dimensional space of the solid, and calculate the three-dimensional coordinates of the solid in the space.

[0069] (9) Calculate the ratio of the stripe phosphorescence signal obtained in step (6) at each of the two wavelengths to obtain the intensity ratio of the stripe phosphorescence signal, and calculate the temperature field information of the stripe interval according to the temperature calibration curve f(R,T); perform interpolation processing on the temperature field information of the stripe interval to obtain the continuous two-dimensional temperature field distribution of the solid surface under test.

[0070] (10) Match the three-dimensional spatial coordinates of the dynamic three-dimensional component with the two-dimensional temperature field of the surface point by point according to the spatial correspondence, and reconstruct the three-dimensional temperature field of the dynamic three-dimensional component.

[0071] The implementation of this invention involves the application of many existing known technologies. For example, the preparation of phosphorescent material sprays by mixing phosphorescent materials and high-temperature adhesives in appropriate proportions; modulation of ultraviolet lasers; optical path construction; temperature curve calibration; calibration of internal and external parameters of digital image acquisition devices and ultraviolet lasers; N-step phase shift algorithm; three-frequency heterodyne method; construction of a phase distribution and three-dimensional coordinate relationship model based on triangulation principles; Fourier transform contour method; spatial phase unfolding algorithm, etc. Matters not covered in this invention are known technologies and are not specifically required.

[0072] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for reconstructing the three-dimensional temperature field of a solid surface based on striped ultraviolet light-excited phosphorescence, characterized in that, The ultraviolet laser is expanded into alternating bright and dark stripes using optical elements and projected onto the surface of the solid being tested, which has a three-dimensional shape. The striped ultraviolet light is used to excite the phosphorescent coating on the surface of the solid being tested, inducing it to generate striped phosphorescent signals. Phosphorescence signal images at different characteristic wavelengths were acquired using a digital image acquisition device. Based on the temperature sensitivity of the phosphorescence signal and the three-dimensional geometric information contained in the stripe phase distribution, the three-dimensional temperature field of the solid surface was measured and reconstructed. For a solid in a static state, the method for reconstructing the three-dimensional temperature field of its surface specifically includes the following steps: (1) Place the calibration plate with a phosphorescent coating on its surface into the inner cavity of the blackbody furnace, and set an optical window on the furnace wall; (2) The ultraviolet laser is controlled by a timing synchronization controller to emit ultraviolet laser. The wavelength of the laser is matched with the excitation characteristics of the phosphorescent material contained in the phosphorescent coating. The laser passes through the optical path composed of a beam expander, a grating, a plano-convex spherical lens, a spatial filter and an aperture in sequence. Due to interference, it generates alternating bright and dark sinusoidal ultraviolet light. Then, the sinusoidal ultraviolet light is irradiated onto the phosphorescent coating of the calibration plate to excite the phosphorescent material to generate striped phosphorescent signals. (3) Using two digital image acquisition devices equipped with narrowband filters, phosphorescent signal images of different characteristic wavelengths are acquired simultaneously through a dichroic mirror, and the coordinates on the two images are kept in correspondence. (4) Adjust the temperature of the blackbody furnace within a certain temperature range at set temperature intervals, record the phosphorescent signal image with a digital image acquisition device and transmit it to the computer for processing: calculate the ratio of the average signal intensities I1 and I2 of two stripe phosphorescent images G1 and G2 with different characteristic wavelengths obtained simultaneously at each temperature T, and obtain the ratio of the stripe phosphorescent signal intensities of the two characteristic wavelengths at that temperature, R = I1 / I2; complete the processing of all temperature-adjusted sampling signals, obtain the response curve f(R, T) of the phosphorescent signal ratio R with temperature T, and complete the temperature curve calibration; (5) Replace the calibration board described in step (1) with a checkerboard calibration board to calibrate the internal and external parameters of the two digital image acquisition devices; on this basis, use the reverse camera calibration method or the pseudo camera calibration method to calibrate the internal and external parameters of the ultraviolet continuous laser used. (6) Referring to the calibration plate described in step (1), a phosphorescent coating is prepared on the surface of the solid to be tested; the checkerboard calibration plate in step (5) is replaced in situ with the solid to be tested, and the solid to be tested is placed in an actual thermal environment; sinusoidal striped ultraviolet light is irradiated onto the surface of the solid to be tested using an ultraviolet continuous laser and optical elements; the stripe frequency f1=10 of the ultraviolet light is kept fixed, but the stripe phase is uniformly and successively shifted by 2π / 3 from the initial state, thereby forming multiple different phosphorescent signal patterns on the surface of the solid to be tested, and phosphorescent signal images at two wavelengths are acquired simultaneously using two digital image acquisition devices; then, the stripe frequency is changed to f2=20 and f3=40, and the above irradiation and acquisition process is repeated; (7) Select the wavelength corresponding to any narrowband filter, and use the standard N-step phase shift algorithm to perform stripe analysis on the phosphorescent signal pattern at each stripe frequency to obtain three sets of truncated phase distribution data of the solid surface under test at different frequencies; use the three-frequency heterodyne method to perform phase expansion and restore the obtained truncated phase to a continuous phase distribution. (8) Based on the internal and external parameters of the digital image acquisition device and the ultraviolet continuous laser calibrated in step (5), and the continuous phase distribution of the solid surface to be measured obtained in step (7), construct a model of the relationship between the phase distribution of the solid to be measured and the three-dimensional coordinates in combination with the principle of triangulation, and calculate the three-dimensional spatial coordinates of the solid to be measured. (9) Calculate the ratio of the three sets of phosphorescent signals with different frequencies obtained in step (6) at two wavelengths point by point to obtain the intensity ratio of the three sets of phosphorescent signals, and calculate the stripe temperature field information according to the temperature calibration curve f (R, T); splice and interpolate the three sets of stripe interval temperature field information to obtain the continuous two-dimensional temperature field distribution of the solid surface under test. (10) Based on the spatial correspondence, the three-dimensional coordinates of the solid under test are matched point by point with the continuous two-dimensional temperature field distribution on the surface, and the three-dimensional temperature field of the solid under test in a static state is obtained by reconstruction; or, For solids in motion, the method for reconstructing the three-dimensional temperature field on their surface specifically includes the following steps: (1) Place the calibration plate with a phosphorescent coating on its surface into the inner cavity of the blackbody furnace, and set an optical window on the furnace wall; (2) The ultraviolet pulse laser is controlled by a timing synchronization controller to emit ultraviolet laser. The wavelength of the laser is matched with the excitation characteristics of the phosphorescent material contained in the phosphorescent coating. The laser passes through the optical path composed of a beam expander, a grating, a plano-convex spherical lens, a spatial filter and an aperture in sequence. Due to interference, it generates alternating bright and dark sinusoidal ultraviolet light. Then, the sinusoidal ultraviolet light is irradiated onto the phosphorescent coating of the calibration plate to excite the phosphorescent material to produce striped phosphorescent signals. (3) A stereo lens is installed at the front end of the digital image acquisition device, and two narrowband filters of different wavelengths are installed in front of the stereo lens; phosphorescent signal images of different characteristic wavelengths are acquired at the same time, and the coordinates on the two images are kept in correspondence. (4) Adjust the temperature of the blackbody furnace within a certain temperature range at set temperature intervals, record the phosphorescent signal image with a digital image acquisition device and transmit it to the computer for processing: calculate the ratio of the average signal intensities I1 and I2 of two stripe phosphorescent images G1 and G2 with different characteristic wavelengths obtained simultaneously at each temperature T, and obtain the ratio of the stripe phosphorescent signal intensities of the two characteristic wavelengths at that temperature, R = I1 / I2; complete the processing of all temperature-adjusted sampling signals, obtain the response curve f(R, T) of the phosphorescent signal ratio R with temperature T, and complete the temperature curve calibration; (5) Replace the calibration plate described in step (1) with a checkerboard calibration plate to calibrate the internal and external parameters of the digital image acquisition device; on this basis, use the reverse camera calibration method or the pseudo camera calibration method to calibrate the internal and external parameters of the ultraviolet pulse laser used. (6) Referring to the calibration plate described in step (1), a phosphorescent coating is prepared on the surface of the solid to be tested; the checkerboard calibration plate in step (5) is replaced in situ with the solid to be tested, and the solid to be tested is placed in an actual thermal environment; sinusoidal ultraviolet light is irradiated onto the surface of the solid to be tested using an ultraviolet pulse laser and optical elements; the stripe frequency of the ultraviolet light is kept fixed and there is no phase shift, and the phosphorescent signal images generated by the surface of the solid to be tested under two wavelengths are acquired simultaneously using a digital image acquisition device; (7) Select any wavelength corresponding to a narrowband filter, use the Fourier transform profile method to perform stripe analysis on a single phosphorescent signal image to obtain the truncated phase distribution data of the dynamic solid under test; use the spatial phase unfolding algorithm to unfold the phase and restore the obtained truncated phase to a continuous phase distribution. (8) Based on the internal and external parameters of the digital image acquisition device and the ultraviolet pulse laser calibrated in step (5), and the continuous phase distribution of the solid surface to be measured obtained in step (7), construct the phase distribution and three-dimensional coordinate relationship model of the solid to be measured in combination with the triangulation principle, and calculate the three-dimensional coordinates of the dynamic three-dimensional component to be measured. (9) Calculate the ratio of the phosphorescent signal intensity at each of the two wavelengths obtained in step (6) to obtain the phosphorescent signal intensity ratio, and calculate the temperature field information of the stripe interval according to the temperature calibration curve f (R, T); perform interpolation processing on the temperature field information of the stripe interval to obtain the continuous two-dimensional temperature field distribution of the solid surface under test. (10) Based on the spatial correspondence, the three-dimensional spatial coordinates of the solid to be measured are matched point by point with the continuous two-dimensional temperature field of the surface to reconstruct the three-dimensional temperature field of the surface of the solid under dynamic conditions.

2. The method according to claim 1, characterized in that, In the process of reconstructing the three-dimensional temperature field of a static solid surface, phosphorescent material Y3Al5O 12 Dy and high-temperature adhesive are mixed in an appropriate ratio to prepare a phosphorescent material spray, which is then sprayed onto the surface of the calibration plate and the solid being tested to form a phosphorescent coating. The ultraviolet continuous laser emits a laser wavelength of 355 nm, and the center wavelengths of the two narrowband filters are 457 nm and 490 nm, respectively.

3. The method according to claim 1, characterized in that, In the process of reconstructing the three-dimensional temperature field of a solid surface in motion, the phosphorescent material BaMgAl is used. 10 O 17 Eu and high-temperature adhesive are mixed in an appropriate ratio to prepare a phosphorescent material spray, which is then sprayed onto the surface of the calibration plate and the solid being tested to form a phosphorescent coating; the ultraviolet pulsed laser emits a laser wavelength of 355 nm, and the center wavelengths of the two narrowband filters are 400 nm and 456 nm, respectively.

4. The method according to claim 1, characterized in that, In step (4), the temperature adjustment range of the blackbody furnace is 400 to 1400 ℃, and the temperature adjustment interval is 10 ℃.

5. The method according to claim 1, characterized in that, In step (5), the intrinsic parameters refer to the focal length, principal point, and distortion of the digital image acquisition device; the extrinsic parameters refer to the posture characteristics of the digital image acquisition device relative to the object, including rotation vector and translation vector.

6. A measurement system based on the solid surface three-dimensional temperature field reconstruction method according to any one of claims 1 to 5, characterized in that, An ultraviolet laser, optical components, and a blackbody furnace are arranged sequentially along the optical path, and a digital image acquisition device is arranged on the side of the optical path. The ultraviolet laser and the digital image acquisition device are respectively connected to a timing synchronization controller via signal lines, and the computer is connected to the digital image acquisition device via signal lines. The blackbody furnace is hollow inside, and optical windows are provided on the furnace wall; a calibration plate with phosphorescent coating, a checkerboard calibration plate, or a solid to be tested with phosphorescent coating is placed in the furnace cavity; The optical element comprises an optical path consisting of a beam expander, a grating, a plano-convex spherical lens, a spatial filter, and an aperture arranged in sequence. It is capable of generating alternating bright and dark sinusoidal ultraviolet light based on interference and projecting it onto the surface of an object in the furnace cavity through an optical window. Depending on the scenarios of static and dynamic measurements, different numbers of digital image acquisition devices are used: when measuring a stationary solid, two digital image acquisition devices are used for image acquisition, and narrowband filters with different center wavelengths are installed in front of their lenses, with a dichroic mirror between the digital image acquisition device and the optical window; when measuring a moving solid, one digital image acquisition device is used for image acquisition, and a stereo lens is installed in front of its lens, with two narrowband filters with different center wavelengths installed in front of the stereo lens. The measurement system also includes a calibration plate with phosphorescent coating, a checkerboard calibration plate, and a solid to be measured with phosphorescent coating, which are placed in the cavity of the blackbody furnace according to the measurement steps.

7. The measurement system according to claim 6, characterized in that, The ultraviolet laser is a pulsed laser or a continuous laser, and the laser energy is adjustable.

8. The measurement system according to claim 6, characterized in that, The digital image acquisition device is a CCD camera, an enhanced CCD camera, a CMOS camera, or an enhanced CMOS camera.

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