An extreme high-temperature environment active imaging digital image correlation device and method

Abstract

This invention discloses an active imaging digital image correlation device and method for extreme high-temperature environments. The device includes an active high-temperature imaging camera, a driven high-temperature imaging camera, an ultraviolet pulsed light source, a host computer, and a test object. The ultraviolet pulsed light source receives a trigger signal from the active high-temperature imaging camera, and the emitted illumination light is reflected by the test object and enters the active and driven high-temperature imaging cameras for imaging. The host computer performs digital image correlation processing on the acquired images to obtain the three-dimensional morphology and strain information of the test object. This invention enables high-temperature digital image correlation measurement of general materials and their samples in an extreme high-temperature environment of 3000℃, obtaining their three-dimensional morphology and strain.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature digital image correlation measurement technology, and particularly relates to an active imaging digital image correlation device and method for extreme high-temperature environments. Background Technology

[0002] During high-temperature digital image correlation measurements, as the temperature rises, the spontaneous emission of the measured object and the ambient light continuously increase. When this reaches a certain level, it will significantly interfere with the imaging, manifesting as increased and homogenized brightness of the measured object, making it difficult to obtain the surface features of the measured object, thus making it impossible to measure the surface morphology and strain of the measured object.

[0003] For this phenomenon, digital image correlation methods typically employ two approaches. One involves using short-wavelength monochromatic illumination with appropriate bandpass filters to reduce spontaneous emission from the sample and ambient light interference, thereby restoring the ability to extract surface features and acquiring the morphology and strain of the sample surface at high temperatures. However, this method is limited by the power of the light source; shorter wavelengths generally require lower power, preventing further increases in applicable temperature. The maximum measurement temperature using this method generally does not exceed 2200℃. The other approach is applied to the measurement of a few special materials. These materials have different compositions in different parts, resulting in different emissivities in certain wavelength bands. The non-uniformity of spontaneous emission intensity in these bands can be utilized to achieve effective imaging. For example, for carbon / tungsten carbide materials, this method can achieve effective imaging at approximately 2600℃. This method requires different parts of the sample to have different emissivities in specific wavelength bands, and the temperature within the test area needs to be relatively uniform to prevent large areas of overexposure or underexposure.

[0004] The above methods have limitations on the use of light sources, materials under test, and measurement temperatures, and cannot be used for the three-dimensional morphology measurement of general materials in extreme high-temperature environments of 3000℃. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an active imaging digital image correlation device and method for extreme high temperature environments, so as to realize high temperature digital image correlation measurement for general materials and their samples in extreme high temperature environments of 3000℃, and obtain their three-dimensional morphology and strain.

[0006] The objective of this invention is achieved through the following technical solution: an active imaging digital image correlation device for extreme high-temperature environments, comprising: an active high-temperature imaging camera, a driven high-temperature imaging camera, an ultraviolet pulse light source, a host computer, and a test object; wherein, the illumination light emitted by the ultraviolet pulse light source after receiving the trigger signal output by the active high-temperature imaging camera is reflected by the test object and enters the active high-temperature imaging camera and the driven high-temperature imaging camera for imaging, and the host computer performs digital image correlation processing on the acquired image to obtain the three-dimensional morphology and strain information of the test object.

[0007] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the ultraviolet pulse light source includes an ultraviolet pulse laser and a laser illumination optical path; wherein, the ultraviolet pulse laser receives a trigger signal output by the active gating camera of the active high-temperature imaging camera, and outputs a laser pulse according to the trigger signal; the laser illumination optical path expands the laser beam to a preset size to obtain illumination light to illuminate the object under test.

[0008] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the laser illumination optical path includes a horizontal guide rail, a primary convex lens, a secondary convex lens, a first vertical guide rail, and a second vertical guide rail; wherein, the first vertical guide rail and the second vertical guide rail are both connected to the horizontal guide rail; the primary convex lens is connected to the first vertical guide rail; and the secondary convex lens is connected to the second vertical guide rail.

[0009] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the active high-temperature imaging camera includes an active gated camera, an active ultraviolet bandpass filter, and an active ultraviolet lens. The active gated camera outputs a trigger signal to the ultraviolet pulse light source and the passive gated camera within the passive high-temperature imaging camera, controlling the light pulse output time of the ultraviolet pulse light source and the exposure delay time of the passive gated camera, thereby synchronizing the active high-temperature imaging camera, the passive high-temperature imaging camera, and the ultraviolet pulse light source. The active ultraviolet bandpass filter allows ultraviolet light reflected from the object being measured to pass through, while blocking light of other wavelengths. The active ultraviolet lens receives the ultraviolet light, thereby forming an image.

[0010] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the driven high-temperature imaging camera includes a driven gated camera, a driven ultraviolet bandpass filter, and a driven ultraviolet lens; wherein, the driven gated camera receives a trigger signal output by the active gated camera and obtains the exposure delay time based on the trigger signal; the driven ultraviolet bandpass filter allows ultraviolet irradiation light in the illumination light reflected by the test object to pass through, while blocking light of other wavelengths from passing through; the driven ultraviolet lens receives ultraviolet irradiation light, thereby forming an image.

[0011] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the host receives a first image from an active high-temperature imaging camera and a second image from a driven high-temperature imaging camera, performs digital image correlation processing on the first and second images, and thereby obtains the three-dimensional morphology and strain information of the object under test.

[0012] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the active gating camera is controlled by the host to adjust the exposure time, and the exposure time control accuracy reaches the nanosecond level; the active gating camera can output multiple trigger pulses within a preset time before and after exposure, and the advance / delay time control accuracy of the trigger pulses relative to the exposure time reaches the nanosecond level, and the times of different trigger pulses are independent of each other.

[0013] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the slave gated camera is controlled by the host to adjust the exposure time, and the exposure time control accuracy reaches the nanosecond level; the slave gated camera receives the trigger pulse from the active gated camera, and the exposure start time is determined by the trigger pulse.

[0014] In the aforementioned active imaging digital image correlation device for extreme high-temperature environments, the transmittance of the active ultraviolet lens and the driven ultraviolet lens is not less than 80%.

[0015] An active imaging digital image correlation method for extreme high-temperature environments includes: an ultraviolet pulsed light source receives a trigger signal output by an active high-temperature imaging camera, and the emitted illumination light is reflected by the object under test and enters the active high-temperature imaging camera and the driven high-temperature imaging camera for imaging; the host performs digital image correlation processing on the acquired image to obtain the three-dimensional morphology and strain information of the object under test.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) Existing high-temperature digital image correlation methods generally only use short-wavelength (blue light, violet light or ultraviolet) illumination combined with narrow bandpass filtering. Due to the limitation of light source power density, the applicable temperature is only about 2000℃, which is difficult to further increase significantly. This invention combines the advantages of pulse illumination + gated camera imaging and ultraviolet illumination + bandpass imaging, and achieves filtering from both time and spectrum dimensions, which greatly improves the shielding effect against interference light, and thus greatly improves the temperature of digital image correlation measurement.

[0018] (2) The ultra-high temperature digital image correlation method that utilizes the difference in emissivity of different parts of special materials in a certain wavelength band is first limited by the choice of materials, and this method requires that the temperature in the measurement area cannot be too different, so as to avoid overexposure in the high temperature area or too low brightness in the low temperature area. The present invention uses active illumination, and the instantaneous power density of the illumination light is much higher than the radiation power density of the corresponding wavelength of the object being measured. Therefore, the temperature distribution and temperature change of the object being measured will not affect the measurement.

[0019] (3) The present invention can achieve nanosecond-level time synchronization and can be used for digital image correlation measurement of objects with rapidly changing surface conditions. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0021] Figure 1 This is a structural block diagram of the active imaging digital image correlation device for extreme high-temperature environments provided in this embodiment of the invention. Detailed Implementation

[0022] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a structural block diagram of the active imaging digital image correlation device for extreme high-temperature environments provided in an embodiment of the present invention. Figure 1 As shown, the active imaging digital image correlation device for extreme high temperature environments includes: an active high temperature imaging camera 1, a passive high temperature imaging camera 2, an ultraviolet pulse light source 3, a host 4, and the object under test 5.

[0024] in,

[0025] The ultraviolet pulse light source 3 receives the trigger signal output by the active high temperature imaging camera 1 and emits illumination light, which is reflected by the test object 5 and enters the active high temperature imaging camera 1 and the driven high temperature imaging camera 2 to form an image. The host 4 performs digital image correlation processing on the acquired image to obtain the three-dimensional morphology and strain information of the test object.

[0026] like Figure 1 As shown, the ultraviolet pulsed light source 3 includes an ultraviolet pulsed laser 301 and a laser illumination optical path 31; wherein, the ultraviolet pulsed laser 301 receives the trigger signal output by the active gating camera of the active high temperature imaging camera 1, and outputs laser pulses according to the trigger signal; the laser illumination optical path 31 expands the laser beam to a preset size to obtain illumination light to irradiate the test object 5.

[0027] like Figure 1 As shown, the laser illumination optical path 31 includes a horizontal guide rail 311, a primary convex lens 312, a secondary convex lens 313, a first vertical guide rail 314, and a second vertical guide rail 315; wherein, the first vertical guide rail 314 and the second vertical guide rail 315 are both connected to the horizontal guide rail 311; the primary convex lens 312 is connected to the first vertical guide rail 314; and the secondary convex lens 313 is connected to the second vertical guide rail 315.

[0028] In the laser illumination optical path 31, the primary convex lens 312 is located on the guide rail 311 near the ultraviolet pulse laser 301, and can move along the guide rail 311 and can be finely adjusted in the direction perpendicular to the guide rail 311; the secondary convex lens 313 is located on the guide rail 311 away from the ultraviolet pulse laser 301, and can move along the guide rail 311 and can be finely adjusted in the direction perpendicular to the guide rail 311.

[0029] The active high-temperature imaging camera 1 includes an active gating camera 101, an active ultraviolet bandpass filter 102, and an active ultraviolet lens 103; wherein,

[0030] The active gating camera 101 outputs a trigger signal to the passive gating camera within the ultraviolet pulsed light source 3 and the passive high-temperature imaging camera 2, controlling the light pulse output time of the ultraviolet pulsed light source 3 and the exposure delay time of the passive gating camera, thus synchronizing the active high-temperature imaging camera 1, the passive high-temperature imaging camera 2, and the ultraviolet pulsed light source 3. The active ultraviolet bandpass filter 102 allows ultraviolet irradiation light reflected from the test object 5 to pass through, while blocking light of other wavelengths. The active ultraviolet lens 103 receives the ultraviolet irradiation light, thereby forming an image. The center wavelengths of the active ultraviolet narrowband pass filter and the passive ultraviolet narrowband pass filter match the center wavelength of the ultraviolet pulsed laser 301, allowing the ultraviolet laser reflected from the test object 5 to pass through, while blocking light of other wavelengths outside a certain bandwidth.

[0031] The active gating camera 101 is controlled by the host 4 to adjust the exposure time, and the exposure time control accuracy reaches the nanosecond level. The active gating camera 101 can output multiple trigger pulses within a certain time before and after the exposure. The advance / delay time control accuracy of the trigger pulses relative to the exposure time reaches the nanosecond level, and the time of different trigger pulses is independent of each other.

[0032] like Figure 1 As shown, the driven high-temperature imaging camera 2 includes a driven gated camera 201, a driven ultraviolet bandpass filter 202, and a driven ultraviolet lens 203; wherein, the driven gated camera 201 receives a trigger signal output by the active gated camera 101 and obtains the exposure delay time according to the trigger signal; the driven ultraviolet bandpass filter 202 allows ultraviolet irradiation light in the irradiation light reflected by the test object 5 to pass through, while blocking light of other wavelengths from passing through; the driven ultraviolet lens 203 receives ultraviolet irradiation light, thereby forming an image.

[0033] The slave gated camera 201 receives control from the host 4 to adjust the exposure time, with the exposure time control accuracy reaching the nanosecond level; the slave gated camera 201 receives the trigger pulse from the active gated camera 101, and the exposure start time is determined by the trigger pulse.

[0034] The host 4 receives the first image from the active high-temperature imaging camera 1 and the second image from the driven high-temperature imaging camera 2, and performs digital image correlation processing on the first and second images to obtain the three-dimensional morphology and strain information of the object under test.

[0035] The host 4 is equipped with gated camera control software, which can control the exposure parameters of the active gated camera 101 and the passive gated camera 201, and control the operation of the passive camera 201 and the ultraviolet pulse laser 301 through the trigger signal of the active gated camera 101.

[0036] The host 4 is equipped with digital image correlation processing software, which can process the images acquired by the active gate camera 101 and the passive gate camera 201 to obtain information such as the three-dimensional shape of the object under test 5.

[0037] During the measurement process, after connecting the equipment and turning on the power, first adjust the ultraviolet pulse laser 301 to the internal trigger mode and turn it on. Adjust the position of the primary convex lens 312 and the secondary convex lens 313 and the distance between them so that the laser beam is expanded to a suitable size and turned to the direction of the object being measured to illuminate the object.

[0038] Subsequently, the ultraviolet pulsed laser 301 and the driven gated camera 201 are adjusted to the external trigger state to receive trigger signals from the active gated camera 101. The host 4 adjusts the exposure gate width and trigger signal delay of the active gated camera 101 and the driven gated camera 201 so that when the pulsed light emitted by the ultraviolet pulsed laser 301 illuminates the test object 5 and returns to the active gated camera 101 and the driven gated camera 201, the exposure of the active gated camera 101 and the driven gated camera 201 is just turned on, and the exposure is just turned off when the returned pulsed light ends.

[0039] After the active gated camera 101, the passive gated camera 201 and the ultraviolet pulsed laser 301 are adjusted, the active imaging digital image correlation device for extreme high temperature environment involved in this invention can image the test object 5 under extreme high temperature environment. After the imaging is completed, the host 4 processes the image to obtain information such as the three-dimensional shape and strain of the test object.

[0040] Both the active and passive high-temperature imaging cameras include an ultraviolet lens, an ultraviolet narrowband pass filter, and a gated camera. The gated camera is controlled by the host unit to achieve nanosecond-level exposure and image acquisition. The active gated camera in the active high-temperature imaging camera outputs a trigger signal to the ultraviolet pulse light source and the passive gated camera in the passive high-temperature imaging camera, controlling the light pulse output time and the exposure delay time of the passive gated camera, thus achieving synchronization between the two gated cameras and the light source. The center wavelength of the ultraviolet narrowband pass filter matches the center wavelength of the ultraviolet pulse light source, allowing the illumination light emitted by the light source reflected from the object under test to pass through while blocking light of other wavelengths. The ultraviolet lens has high transmittance for ultraviolet illumination light, ensuring good image quality. The ultraviolet pulsed light source includes an ultraviolet pulsed laser and a laser illumination optical path. The ultraviolet pulsed laser receives a trigger signal from a gated camera and outputs laser pulses according to the trigger signal. The laser illumination optical path includes a guide rail and two convex lenses that can move along the guide rail and be finely adjusted in the direction perpendicular to the guide rail. This allows the laser beam to be expanded and projected onto the object under test, and the illumination angle and beam width can be adjusted. The host controls the imaging and triggering parameters of the gated camera to achieve high imaging quality and processes images from the two gated cameras. Data such as the morphology of the object under test are obtained through digital image correlation calculations. The active imaging digital image correlation device and method for extreme high-temperature environments of this invention have stronger resistance to thermal radiation from the object under test and environmental interference, and can be applied to the three-dimensional morphology measurement needs in extreme high-temperature environments of 3000℃.

[0041] This embodiment also provides a method for active imaging digital image correlation in extreme high-temperature environments, the method comprising:

[0042] The ultraviolet pulse light source 3 receives the trigger signal output by the active high temperature imaging camera 1 and emits illumination light, which is reflected by the test object 5 and enters the active high temperature imaging camera 1 and the driven high temperature imaging camera 2 to form an image. The host 4 performs digital image correlation processing on the acquired image to obtain the three-dimensional morphology and strain information of the test object.

[0043] Existing high-temperature digital image correlation methods generally employ only short-wavelength (blue, violet, or ultraviolet) illumination combined with narrow-bandpass filtering. Limited by the power density of the light source, the maximum applicable temperature is only around 2000℃, making further significant increases difficult. This invention combines the advantages of pulsed illumination + gated camera imaging and ultraviolet illumination + bandpass imaging, achieving filtering from both temporal and spectral dimensions. This significantly improves the shielding effect against interfering light, thereby greatly increasing the measurement temperature for digital image correlation. Ultra-high-temperature digital image correlation methods utilizing the difference in emissivity of different parts of special materials at certain wavelengths are limited by material selection, and this method requires that the temperature difference within the measurement area not be too large to avoid overexposure in high-temperature areas or insufficient brightness in low-temperature areas. This invention uses active illumination, and the instantaneous power density of the illumination light is much higher than the corresponding wavelength radiation power density of the measured object. Therefore, the temperature distribution and temperature changes of the measured object will not affect the measurement. This invention can achieve nanosecond-level time synchronization and can be used for digital image correlation measurements of objects with rapidly changing surface states.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A digital image correlation device for active imaging in extreme high-temperature environments, characterized in that... include: An active high-temperature imaging camera (1), a driven high-temperature imaging camera (2), an ultraviolet pulse light source (3), a main unit (4), and the object under test (5); among which, The ultraviolet pulse light source (3) receives the trigger signal output by the active high temperature imaging camera (1) and emits illumination light that is reflected by the test object (5) and enters the active high temperature imaging camera (1) and the driven high temperature imaging camera (2) for imaging. The host (4) performs digital image correlation processing on the obtained image to obtain the three-dimensional morphology and strain information of the test object. The ultraviolet pulsed light source (3) includes an ultraviolet pulsed laser (301) and a laser illumination optical path (31); wherein, The ultraviolet pulsed laser (301) receives the trigger signal output by the active high-temperature imaging camera (1) and outputs laser pulses according to the trigger signal; The laser illumination optical path (31) expands the laser beam to a preset size to illuminate the test object (5); The laser illumination optical path (31) includes a horizontal guide rail (311), a primary convex lens (312), a secondary convex lens (313), a first vertical guide rail (314), and a second vertical guide rail (315); wherein, Both the first vertical guide rail (314) and the second vertical guide rail (315) are connected to the horizontal guide rail (311); The primary convex lens (312) is connected to the first vertical guide rail (314); The secondary convex lens (313) is connected to the second vertical guide rail (315); The active high-temperature imaging camera (1) includes an active gated camera (101), an active ultraviolet bandpass filter (102), and an active ultraviolet lens (103); wherein, The active gating camera (101) outputs a trigger signal to the ultraviolet pulse light source (3) and the driven high-temperature imaging camera (2), controlling the light pulse output time of the ultraviolet pulse light source (3) and the exposure delay time of the driven gating camera, so that the active high-temperature imaging camera (1), the driven high-temperature imaging camera (2) and the ultraviolet pulse light source (3) are synchronized. The active ultraviolet bandpass filter (102) allows ultraviolet irradiation light in the irradiation light reflected by the test object (5) to pass through, while blocking light of other wavelengths from passing through; The active ultraviolet lens (103) receives ultraviolet light to form an image; The driven high-temperature imaging camera (2) includes a driven gating camera (201), a driven ultraviolet bandpass filter (202), and a driven ultraviolet lens (203); wherein, The passive gated camera (201) receives the trigger signal output by the active gated camera (101) and obtains the exposure delay time based on the trigger signal; The driven ultraviolet bandpass filter (202) allows ultraviolet irradiation light in the irradiation light reflected by the test object (5) to pass through, while blocking light of other wavelengths from passing through; The driven ultraviolet lens (203) receives ultraviolet light to form an image; The host (4) receives the first image from the active high-temperature imaging camera (1) and the second image from the driven high-temperature imaging camera (2), performs digital image correlation processing on the first and second images, and thus obtains the three-dimensional morphology and strain information of the object under test. The active gated camera (101) is controlled by the host (4) to adjust the exposure time, and the exposure time control accuracy reaches the nanosecond level. The active gated camera (101) can output multiple trigger pulses within a preset time before and after the exposure. The advance / delay time control accuracy of the trigger pulse relative to the exposure time reaches the nanosecond level, and the time of different trigger pulses is independent of each other. The slave gated camera (201) is controlled by the host (4) to adjust the exposure time, and the exposure time control accuracy reaches the nanosecond level; the slave gated camera (201) receives the trigger pulse from the active gated camera (101), and the exposure start time is determined by the trigger pulse.

2. The active imaging digital image correlation device for extreme high-temperature environments according to claim 1, characterized in that: The transmittance of the active ultraviolet lens (103) and the driven ultraviolet lens (203) is not less than 80%.

3. A method for performing active imaging digital image correlation in extreme high-temperature environments using the extreme high-temperature environment active imaging digital image correlation device according to any one of claims 1-2, characterized in that... include: During the measurement process, after connecting the equipment and turning on the power, first adjust the ultraviolet pulse laser to the internal trigger mode and turn it on. Adjust the position of the primary convex lens and the secondary convex lens and the distance between them so that the laser beam is expanded to a suitable size and turned to the direction of the object being measured to illuminate the object. Subsequently, the ultraviolet pulsed laser and the slave gating camera are adjusted to the external trigger state to receive trigger signals from the active gating camera; By adjusting the exposure gate width and trigger signal delay of the active and passive gated cameras by the host, the pulsed light emitted by the ultraviolet pulsed laser illuminates the object under test and returns to the active and passive gated cameras. The exposure of the active and passive gated cameras is just turned on when the pulsed light returns and the exposure is just turned off when the pulsed light ends.

Images