Crack detection method, device, electronic equipment and storage medium

Abstract

The present invention provides a crack detection method, device, electronic device and storage medium, the method comprising: determining a test area of ​​a test piece to be tested and a detection path on the surface of the test area; according to the detection path, using a joint scanner composed of a laser and a thermal imager to jointly scan the surface of the test area to obtain a scanning thermal map; determining crack detection sampling points in the scanning thermal map, and judging whether there are cracks on the surface of the test area based on the crack detection sampling points, and if there are cracks on the surface of the test area, determining the position of the cracks. The present invention can detect cracks on the surface of a large area of ​​material by using a joint scanner composed of a laser and a thermal imager to jointly scan the surface of the test area, and judging whether there are cracks on the surface of the test area based on the crack detection sampling points in the scanning thermal map, thereby effectively realizing blind detection of cracks on the surface of the test area.

Description

Technical Field

[0001] The present invention relates to the technical field of crack detection, and in particular to a crack detection method, device, electronic equipment and storage medium. Background Art

[0002] Laser thermal imaging is an emerging infrared thermal imaging nondestructive testing technology. Laser excitation can produce a horizontal temperature gradient, which has great potential in surface crack detection and has the advantages of non-contact and simple operation.

[0003] According to different laser excitation processes, a variety of laser thermal imaging methods have been developed, such as laser flying spot, laser pulse, long pulse and laser phase-locked laser thermal imaging technologies, which can detect tiny fatigue cracks on the surface ranging from a few microns to tens of microns. However, the above methods all require the ability to estimate the location of fatigue cracks in the structure to be inspected, and only under this premise can imaging and quantitative evaluation research be carried out. Moreover, blind detection of surface cracks in large structures such as aircraft skins and spacecraft main structures is rare, and there is no existing feasible detection method. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a crack detection method, device, electronic equipment and storage medium.

[0005] In a first aspect, the present invention provides a crack detection method, comprising:

[0006] Determine a test area of ​​the test piece to be tested and a detection path on the surface of the test area;

[0007] According to the detection path, a combined scanner composed of a laser and a thermal imager is used to jointly scan the surface of the area to be detected to obtain a scanning thermal map;

[0008] Determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, judge whether there are cracks on the surface of the area to be tested, and if the cracks exist on the surface of the area to be tested, determine the position of the cracks.

[0009] Optionally, according to a crack detection method provided by the present invention, the determining of crack detection sampling points in the scanning thermal map includes:

[0010] Selecting the leading edge of the hot spot in the scanning thermal image in the scanning direction as the crack detection sampling point, the leading edge of the hot spot in the scanning direction is a pixel at a first preset distance from the center of the hot spot along the scanning direction of the hot spot, or a pixel at a second preset distance from the center line of the line width of the line hot spot along the scanning direction of the line hot spot;

[0011] Wherein, the first preset distance does not exceed the radius of the hot spot, and the second preset distance does not exceed half of the line width of the line hot spot.

[0012] Optionally, according to a crack detection method provided by the present invention, judging whether there is a crack on the surface of the area to be tested based on the crack detection sampling point, and if the crack exists on the surface of the area to be tested, determining the position of the crack includes:

[0013] The amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point are used as feature quantities for crack detection. Based on the feature quantities for crack detection, it is determined whether there is a crack on the surface of the area to be tested. If the crack exists on the surface of the area to be tested, the position of the crack is determined.

[0014] Optionally, according to a crack detection method provided by the present invention, the amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point are used as feature quantities for crack detection, and according to the feature quantities for crack detection, it is judged whether there is a crack on the surface of the area to be detected, and if there is a crack on the surface of the area to be detected, the position of the crack is determined, including:

[0015] Determining a first temperature time series of the crack detection sampling point;

[0016] Using a wavelet analysis method to filter the low-frequency trend term and the high-frequency noise term of the first temperature time series, and using the filtered first temperature time series as the second temperature time series;

[0017] The second temperature time series is subjected to a self-similarity analysis based on DB wavelet to obtain a distribution diagram of the self-similarity coefficient, in which the maximum value of the self-similarity coefficient represents a crack, and the position corresponding to the maximum value of the self-similarity coefficient represents the position of the crack.

[0018] Optionally, according to a crack detection method provided by the present invention, the method further includes:

[0019] The laser power of the laser is set according to the surface absorptivity and damage threshold of the test piece to be inspected, so that the center temperature of the hot spot in the scanning thermal image at least reaches a preset temperature value.

[0020] Optionally, according to a crack detection method provided by the present invention, the method further includes:

[0021] The range of the self-similarity coefficient s is set according to the formula v*s=C, where v is the joint scanning speed and C is a constant;

[0022] The constant C is determined by performing multi-speed detection on the test piece to be detected, and the constant C is related to the laser diameter of the laser and the thermal diffusion coefficient of the test piece to be detected.

[0023] In a second aspect, the present invention further provides a crack detection device, comprising:

[0024] A determination module, used to determine a test area of ​​the test piece to be detected and a detection path on the surface of the test area;

[0025] A scanning module, used to perform a joint scan on the surface of the area to be tested using a joint scanner composed of a laser and a thermal imager according to the detection path to obtain a scanning thermal map;

[0026] The detection module is used to determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, determine whether there are cracks on the surface of the area to be tested, and if there are cracks on the surface of the area to be tested, determine the position of the crack.

[0027] In a third aspect, the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the crack detection method described in the first aspect are implemented.

[0028] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the crack detection method described in the first aspect.

[0029] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the crack detection method as described in the first aspect are implemented.

[0030] The crack detection method, device, electronic device and storage medium provided by the present invention can detect cracks on the surface of the area to be tested by jointly scanning the surface of the area to be tested with a combined scanner composed of a laser and a thermal imager to obtain a scanning thermal map, thereby realizing the detection of cracks on the surface of a large area of ​​material. Moreover, based on the crack detection sampling points in the scanning thermal map, it is determined whether there are cracks on the surface of the area to be tested. If cracks exist, the location of the cracks is determined, thereby effectively realizing blind detection of cracks on the surface of the area to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a schematic diagram of the process of the crack detection method provided by the present invention;

[0033] Figure 2 It is a schematic diagram of the detection principle of the crack detection method provided by the present invention;

[0034] Figure 3 It is one of the schematic diagrams of crack detection sampling points of the crack detection method provided by the present invention;

[0035] Figure 4 This is the second schematic diagram of crack detection sampling points of the crack detection method provided by the present invention;

[0036] Figure 5 It is a schematic diagram of the amplitude and waveform of the temperature change at the crack detection sampling point of the crack detection method provided by the present invention;

[0037] Figure 6 It is a second temperature time series schematic diagram of the crack detection method provided by the present invention;

[0038] Figure 7 is a schematic diagram of the distribution of the self-similarity coefficient of the crack detection method provided by the present invention;

[0039] Figure 8 It is a structural schematic diagram of a crack detection device provided by the present invention;

[0040] Fig. 9 An example physical structure diagram of an electronic device is provided. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Combine the following Figure 1-Figure 8 The present invention describes a crack detection method and a crack detection device.

[0043] Figure 1 Schematic diagram of the crack detection method provided by the present invention. Figure 1 As shown, the method includes the following process:

[0044] Step 100, determining a test area of ​​the test piece to be tested and a detection path on the surface of the test area;

[0045] Step 110, according to the detection path, using a combined scanner composed of a laser and a thermal imager to jointly scan the surface of the to-be-detected area to obtain a scanning thermal map;

[0046] Step 120, determining crack detection sampling points in the scanning thermal image, and judging whether there are cracks on the surface of the test area based on the crack detection sampling points, and if there are cracks on the surface of the test area, determining the position of the crack.

[0047] Optionally, the material of the test piece to be inspected may include metals with low surface absorption rate, such as aluminum alloy, etc., and may also include common metals, such as steel, iron, etc.

[0048] Optionally, the detection path may be kept parallel to the surface of the test piece to be detected.

[0049] Optionally, according to the detection path, a combined scanner composed of a laser and a thermal imager may be used to jointly scan the surface of the area to be detected to obtain a scanning thermal map.

[0050] Optionally, the hot spot where the laser light emitted by the laser is focused can be a point hot spot, a line hot spot or a hot spot in the form of an array, and the present invention does not make any specific limitation to this.

[0051] Optionally, when the hot spot focused by the laser is a linear hot spot, during the scanning process, the linear hot spot can be kept perpendicular to the scanning direction of the linear hot spot.

[0052] Optionally, the power of the laser can be adjustable in the range of 0-100W.

[0053] Optionally, a semiconductor laser may be used to excite heat on the surface of the area to be measured, and the excitation power may be selected according to the surface absorptivity and damage threshold of the area to be measured.

[0054] Optionally, the noise equivalent temperature difference (NETD) of the thermal imager may be no greater than 50 mK.

[0055] Optionally, crack detection sampling points in the scanning thermal image recorded by the thermal imager can be determined. Based on the crack detection sampling points, it can be determined whether there are cracks on the surface of the test area. If there are cracks on the surface of the test area, the position of the crack is determined.

[0056] It should be noted that the crack detection method provided by the present invention focuses on detecting whether there are cracks on the surface of the test piece to be inspected and determining the location of the cracks, while the existing laser thermal imaging technology is mainly used for visual detection of cracks and is not suitable for large-scale crack detection scenarios.

[0057] Figure 2Schematic diagram of the detection principle of the crack detection method provided by the present invention, such as Figure 2 As shown, the present invention is composed of a power supply, a semiconductor laser, a thermal imager and a terminal control computer. The laser collimator and the thermal imager are fixed on a scanning moving part (such as an electrically controlled translation stage, etc.) to form a joint scanning module. The scanning path is kept roughly parallel to the surface of the test piece to be inspected; the thermal imager, the laser and the moving part are kept synchronously controlled. When the joint scanning module starts to move, the thermal imager is synchronously triggered to start recording the thermal image.

[0058] Optionally, before the joint scanning, the distance from the joint scanning module to the surface of the test piece and the focusing lens on the surface of the thermal imager can be set so that the thermal imager can clearly image the hot spot.

[0059] Optionally, the area to be inspected and the scanning route may be determined according to the requirements of the inspection task.

[0060] Optionally, the combined scan can be completed under computer control, the thermal imager synchronously records the scanned thermal image, and the computer synchronously transmits and stores the thermal image recorded by the thermal imager.

[0061] Optionally, the scanning speed can be set arbitrarily according to specific requirements, and the present invention does not make any specific limitation to this.

[0062] Optionally, the test area of ​​the test piece to be tested and the detection route on the surface of the test area to be tested can be determined first according to the requirements of the detection task; then a joint scanner composed of a laser and a thermal imager can be used to jointly scan the surface of the test area based on the detection path. During the scanning process, the relative positions of the laser and the thermal imager can remain unchanged, so that the position of the hot spot in the thermal image remains stationary, and scanning of a large area of ​​the material surface can be achieved; finally, the crack detection sampling points in the scanned thermal image are determined, and based on the crack detection sampling points, it is determined whether there are cracks in the test area. If cracks exist, the position of the cracks is determined, thereby effectively achieving blind detection of cracks on the surface of the test area.

[0063] The crack detection method provided by the present invention can detect cracks on the surface of the area to be tested by jointly scanning the surface of the area to be tested with a combined scanner composed of a laser and a thermal imager to obtain a scanning thermal image, thereby realizing the detection of cracks on the surface of a large area of ​​material. Moreover, based on the crack detection sampling points in the scanning thermal image, it is determined whether there are cracks on the surface of the area to be tested. If cracks exist, the position of the cracks is determined, thereby effectively realizing blind detection of cracks on the surface of the area to be tested.

[0064] Optionally, determining the crack detection sampling points in the scanning thermal map includes:

[0065] Selecting the leading edge of the hot spot in the scanning thermal image in the scanning direction as the crack detection sampling point, the leading edge of the hot spot in the scanning direction is a pixel at a first preset distance from the center of the hot spot along the scanning direction of the hot spot, or a pixel at a second preset distance from the center line of the line width of the line hot spot along the scanning direction of the line hot spot;

[0066] Wherein, the first preset distance does not exceed the radius of the hot spot, and the second preset distance does not exceed half of the line width of the line hot spot.

[0067] Optionally, the leading edge of the hot spot in the scanning thermal image in the scanning direction may be selected as the crack detection sampling point.

[0068] Optionally, the leading edge of the hot spot in the scanning direction may be a pixel at a first preset distance from the center of the hot spot along the scanning direction of the hot spot.

[0069] Optionally, the leading edge of the hot spot in the scanning direction may be a pixel at a second preset distance from a center line of the line width of the line hot spot along the scanning direction of the line hot spot.

[0070] Optionally, the first preset distance may be 1 / 2 of the hot spot diameter.

[0071] Optionally, the second preset distance may be 1 / 2 line width of the line hot spot.

[0072] Experimental verification shows that the temperature signal of the crack at the sampling point about 1 / 2 hot spot diameter in front of the laser excitation point along the scanning direction has a larger signal-to-noise ratio. The pixel at 1 / 2 hot spot diameter away from the center of the hot spot is most suitable for crack detection and is the best sampling point. Similarly, the pixel at 1 / 2 line width away from the center line of the line hot spot is most suitable for crack detection and is the best sampling point.

[0073] Figure 3 is one of the schematic diagrams of crack detection sampling points of the crack detection method provided by the present invention, Figure 4 FIG. 2 is a second schematic diagram of crack detection sampling points of the crack detection method provided by the present invention, such as Figure 3 As shown, when the hot spot is a point hot spot or an array hot spot, the pixel at a distance of about 1 / 2 of the hot spot diameter from the center of the hot spot along the scanning direction of the hot spot is selected as the crack detection sampling point; Figure 4 As shown, when the hot spot is a linear hot spot, the pixel at a distance of 1 / 2 line width from the center line of the line width of the linear hot spot along the scanning direction of the hot spot is selected as the crack detection sampling point.

[0074] The present invention samples the hot spots in the thermal image and selects the leading edge of the hot spots in the scanning direction as the crack detection sampling point, thereby effectively ensuring that the crack signal obtained by the selected crack detection sampling point in the scanning has a large signal-to-noise ratio, which helps to improve the detection accuracy of fatigue cracks on the surface of low-absorption materials.

[0075] Optionally, judging whether there is a crack on the surface of the area to be tested based on the crack detection sampling point, and if the crack exists on the surface of the area to be tested, determining the position of the crack includes:

[0076] The amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point are used as feature quantities for crack detection. Based on the feature quantities for crack detection, it is determined whether there is a crack on the surface of the area to be tested. If the crack exists on the surface of the area to be tested, the position of the crack is determined.

[0077] Optionally, the amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point may be used as feature quantities for crack detection.

[0078] Optionally, it is possible to determine whether cracks exist on the surface of the area to be tested based on the characteristic quantity of crack detection. If cracks exist on the surface of the area to be tested, the position of the cracks can be determined.

[0079] Figure 5 Schematic diagram of the amplitude and waveform of the temperature change at the crack detection sampling point of the crack detection method provided by the present invention, such as Figure 5 As shown in the figure, at the laser joint scanning thermal imaging sampling point, the temperature characteristics of the crack have a large temperature change amplitude A and a specific "peak-valley-peak" three-pole waveform, where δ represents the time difference from the peak to the trough. At a fixed thermal imager frame rate (sampling rate), the smaller δ is, the lower the accuracy of the thermal imager in capturing the amplitude A; at a certain frame rate, a larger amplitude is conducive to the characterization of the crack.

[0080] Optionally, the using the amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point as the characteristic quantity of crack detection, judging whether there is a crack on the surface of the area to be detected according to the characteristic quantity of crack detection, and if there is a crack on the surface of the area to be detected, determining the position of the crack includes:

[0081] Determining a first temperature time series of the crack detection sampling point;

[0082] Using a wavelet analysis method to filter the low-frequency trend term and the high-frequency noise term of the first temperature time series, and using the filtered first temperature time series as the second temperature time series;

[0083] The second temperature time series is subjected to a self-similarity analysis based on DB wavelet to obtain a distribution diagram of the self-similarity coefficient, in which the maximum value of the self-similarity coefficient represents a crack, and the position corresponding to the maximum value of the self-similarity coefficient represents the position of the crack.

[0084] Optionally, a first temperature time series of crack detection sampling points may be determined according to the sampling points in the thermal map.

[0085] Optionally, the first temperature time series may be denoised and enhanced using a wavelet analysis method, that is, the low-frequency trend term and the high-frequency noise term of the first temperature time series may be filtered out, and the remainder is used as the second temperature time series.

[0086] Optionally, a DB wavelet-based self-similarity analysis may be performed on the second temperature time series to obtain a distribution diagram of the self-similarity coefficient. In the distribution diagram, the maximum value of the self-similarity coefficient may represent a crack, and the position corresponding to the maximum value of the self-similarity coefficient may represent the position of the crack.

[0087] Optionally, a self-similarity analysis based on DB4, DB3 or DB2 wavelet may be performed on the second temperature time series, wherein DB3 and DB2 are suitable for the case where the signal-to-noise ratio is low.

[0088] Figure 6 is a second temperature time series schematic diagram of the crack detection method provided by the present invention, Figure 7 is a schematic diagram of the distribution of the self-similarity coefficient of the crack detection method provided by the present invention, such as Figure 6 and Figure 7 As shown, Figure 6 The second temperature time series in the DB wavelet self-similarity analysis can be obtained as follows Figure 7 The position-scale distribution diagram of the self-similarity coefficient in , where Figure 7 The small circle in the figure represents the maximum value of the wavelet similarity coefficient. The horizontal axis represents the location of the crack, and the vertical axis represents the scale of the wavelet, which contains the scanning speed information.

[0089] Combination Figure 6 and Figure 7 It can be seen that the characteristic of the crack is that the larger values ​​(including extreme values) of the self-similarity coefficient are concentrated on an obvious "ridge" perpendicular to the position coordinate, which is exactly the location of the "valley" of the thermal signal.

[0090] The enhanced denoising method based on wavelet decomposition of the present invention filters the low-frequency trend terms and high-frequency noise terms of the first temperature time series, and uses the remaining as the second temperature time series, which effectively improves the signal-to-noise ratio and can effectively restore the typical "three-pole" waveform at the crack. Based on the similarity between the second temperature time series and the DB wavelet, the amplitude characteristics and waveform characteristics of the temperature change of the crack in the joint scan are converted into the extreme value of the similarity coefficient, which effectively realizes the automation of surface crack detection and has sensitive detection capability for fatigue microcracks of 10μm.

[0091] Optionally, the method further comprises:

[0092] The laser power of the laser is set according to the surface absorptivity and damage threshold of the test piece to be inspected, so that the center temperature of the hot spot in the scanning thermal image at least reaches a preset temperature value.

[0093] Optionally, the laser power of the laser can be set according to the surface absorptivity and damage threshold of the test piece to be inspected, so that the center temperature of the hot spot in the scanning thermal image can at least reach a preset temperature value.

[0094] Optionally, the preset temperature value may be set to 1K, 1.5K, 2K, etc., which is not specifically limited in the present invention.

[0095] Optionally, the method further comprises:

[0096] The range of the self-similarity coefficient s is set according to the formula v*s=C, where v is the joint scanning speed and C is a constant;

[0097] The constant C is determined by performing multi-speed detection on the test piece to be detected, and the constant C is related to the laser diameter of the laser and the thermal diffusion coefficient of the test piece to be detected.

[0098] Optionally, the range of the self-similarity coefficient s may be set according to the formula v*s=C to perform crack detection more accurately, wherein the constant C may be determined by performing multi-speed detection on the test piece to be detected.

[0099] The present invention helps to improve the crack detection accuracy by presetting the range of the self-similarity coefficient.

[0100] The crack detection device provided by the present invention is described below. The crack detection device described below and the crack detection method described above can be referred to each other.

[0101] Figure 8 Schematic diagram of the structure of the crack detection device provided by the present invention, such as Figure 8 As shown, the device includes: a determination module 810, a scanning module 820 and a detection module 830; wherein:

[0102] The determination module 810 is used to determine the area to be tested of the test piece to be tested and the detection path on the surface of the area to be tested;

[0103] The scanning module 820 is used to perform a joint scan on the surface of the to-be-tested area using a joint scanner composed of a laser and a thermal imager according to the detection path to obtain a scanning thermal map;

[0104] The detection module 830 is used to determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, determine whether there are cracks on the surface of the area to be tested, and if there are cracks on the surface of the area to be tested, determine the position of the crack.

[0105] Optionally, the crack detection device can determine the test area of ​​the test piece to be tested and the detection path on the surface of the test area through the determination module 810, and then according to the detection path, the surface of the test area can be jointly scanned by a combined scanner composed of a laser and a thermal imager through the scanning module 820 to obtain a scanning thermal map; and the crack detection sampling points in the scanning thermal map can be determined through the detection module 830, and based on the crack detection sampling points, it is judged whether there are cracks on the surface of the test area; if there are cracks on the surface of the test area, the position of the crack is determined.

[0106] The crack detection device provided by the present invention can detect cracks on the surface of the area to be tested by jointly scanning the surface of the area to be tested with a combined scanner composed of a laser and a thermal imager to obtain a scanning thermal image, thereby realizing the detection of cracks on the surface of a large area of ​​material. Moreover, based on the crack detection sampling points in the scanning thermal image, it is determined whether there are cracks on the surface of the area to be tested. If cracks exist, the position of the cracks is determined, thereby effectively realizing blind detection of cracks on the surface of the area to be tested.

[0107] Fig. 9 An example of a physical structure diagram of an electronic device is shown in FIG. Fig. 9 As shown, the electronic device may include: a processor 910, a communication interface 920, a memory 930 and a communication bus 940, wherein the processor 910, the communication interface 920 and the memory 930 communicate with each other through the communication bus 940. The processor 910 may call the logic instructions in the memory 930 to execute the crack detection method provided by the above methods, and the method includes:

[0108] Determine a test area of ​​the test piece to be tested and a detection path on the surface of the test area;

[0109] According to the detection path, a combined scanner composed of a laser and a thermal imager is used to jointly scan the surface of the area to be detected to obtain a scanning thermal map;

[0110] Determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, judge whether there are cracks on the surface of the area to be tested, and if the cracks exist on the surface of the area to be tested, determine the position of the cracks.

[0111] In addition, the logic instructions in the above-mentioned memory 930 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0112] On the other hand, the present invention further provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, when the program instructions are executed by a computer, the computer can execute the crack detection method provided by the above methods, the method comprising:

[0113] Determine a test area of ​​the test piece to be tested and a detection path on the surface of the test area;

[0114] According to the detection path, a combined scanner composed of a laser and a thermal imager is used to jointly scan the surface of the area to be detected to obtain a scanning thermal map;

[0115] Determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, judge whether there are cracks on the surface of the area to be tested, and if the cracks exist on the surface of the area to be tested, determine the position of the cracks.

[0116] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method is implemented to perform the above-mentioned crack detection method, the method comprising:

[0117] Determine a test area of ​​the test piece to be tested and a detection path on the surface of the test area;

[0118] According to the detection path, a combined scanner composed of a laser and a thermal imager is used to jointly scan the surface of the area to be detected to obtain a scanning thermal map;

[0119] Determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, judge whether there are cracks on the surface of the area to be tested, and if the cracks exist on the surface of the area to be tested, determine the position of the cracks.

[0120] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0121] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A crack detection method, characterized in that: include: Determine a test area of ​​the test piece to be tested and a detection path on the surface of the test area; According to the detection path, a combined scanner composed of a laser and a thermal imager is used to jointly scan the surface of the area to be detected to obtain a scanning thermal map, wherein the laser and the thermal imager are fixed on a scanning moving part to form the combined scanner; Determine crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, judge whether there are cracks on the surface of the area to be tested, and if the cracks exist on the surface of the area to be tested, determine the position of the cracks; The step of determining the crack detection sampling points in the scanning thermal image comprises: Selecting the leading edge of the hot spot in the scanning thermal image in the scanning direction as the crack detection sampling point, the leading edge of the hot spot in the scanning direction is a pixel at a first preset distance from the center of the hot spot along the scanning direction of the hot spot, or a pixel at a second preset distance from the center line of the line width of the line hot spot along the scanning direction of the line hot spot; Wherein, the first preset distance does not exceed the radius of the hot spot, and the second preset distance does not exceed half of the line width of the line hot spot; The determining, based on the crack detection sampling points, whether there is a crack on the surface of the area to be tested, and if the crack exists on the surface of the area to be tested, determining the position of the crack comprises: The amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point are used as the characteristic quantities of crack detection, and whether there is a crack on the surface of the to-be-tested area is judged according to the characteristic quantities of crack detection, and if the crack exists on the surface of the to-be-tested area, the position of the crack is determined; The method of using the amplitude characteristics and waveform characteristics of the temperature change at the crack detection sampling point as the characteristic quantity of crack detection, judging whether there is a crack on the surface of the to-be-detected area according to the characteristic quantity of crack detection, and determining the position of the crack if there is a crack on the surface of the to-be-detected area, comprises: Determining a first temperature time series of the crack detection sampling point; Using a wavelet analysis method to filter the low-frequency trend term and the high-frequency noise term of the first temperature time series, and using the filtered first temperature time series as the second temperature time series; The second temperature time series is subjected to a self-similarity analysis based on DB wavelet to obtain a distribution diagram of the self-similarity coefficient, in which the maximum value of the self-similarity coefficient represents a crack, and the position corresponding to the maximum value of the self-similarity coefficient represents the position of the crack.

2. The crack detection method according to claim 1, characterized in that: The method further comprises: The laser power of the laser is set according to the surface absorptivity and damage threshold of the test piece to be inspected, so that the center temperature of the hot spot in the scanning thermal image at least reaches a preset temperature value.

3. The crack detection method according to claim 1, characterized in that: The method further comprises: The range of the self-similarity coefficient s is set according to the formula v*s=C, where v is the joint scanning speed and C is a constant; The constant C is determined by performing multi-speed detection on the test piece to be detected, and the constant C is related to the laser diameter of the laser and the thermal diffusion coefficient of the test piece to be detected.

4. A crack detection device, characterized in that: The crack detection method according to claim 1 comprises: A determination module, used to determine a test area of ​​the test piece to be detected and a detection path on the surface of the test area; A scanning module, used to perform a joint scan on the surface of the area to be tested using a joint scanner composed of a laser and a thermal imager according to the detection path to obtain a scanning thermal map; The detection module is used to determine the crack detection sampling points in the scanning thermal image, and based on the crack detection sampling points, determine whether there are cracks on the surface of the area to be tested, and if there are cracks on the surface of the area to be tested, determine the position of the crack.

5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the crack detection method according to any one of claims 1 to 3 are implemented.

6. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the crack detection method according to any one of claims 1 to 3 are implemented.

7. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the crack detection method according to any one of claims 1 to 3 are implemented.

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