CN115112636B - Photo-thermal three-dimensional characteristic reconstruction system and reconstruction method based on phase control array laser beam concentration excitation - Google Patents
Photo-thermal three-dimensional characteristic reconstruction system and reconstruction method based on phase control array laser beam concentration excitation Download PDFInfo
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Abstract
The invention provides a photo-thermal three-dimensional characteristic reconstruction system and a reconstruction method based on phase control array laser beam bundling excitation. The reconstruction system comprises a computer, a multi-channel data line, a first data acquisition card, a second data acquisition card, a third data acquisition card, a data acquisition card integrator, a multi-channel signal output line, a laser power supply, a cooling water pipe, a refrigerator, an optical fiber bundle, a collimating mirror, a first polaroid, a sample, a two-dimensional mobile station, a second polaroid, a magnetic seat, a focal plane thermal infrared imager, a lifting table, a BNC data line and an Ethernet line. The system adopts the phase control array type laser beam bundling to carry out active heat loading on the sample, and single laser beams in the array type laser beam bundling can be independently controlled, so that the spatial modulation of the heat flow of the sample can be realized, further, the high-precision detection of the defect size can be realized, and the defect detection deviation is controlled within 5%.
Description
Technical Field
The invention belongs to the technical fields of photothermal science, detection and signal processing, and particularly relates to a photothermal three-dimensional characteristic reconstruction system and a reconstruction method based on phase control array laser beam concentration excitation. The reconstruction method and the reconstruction system are suitable for the fields of precise nondestructive detection and evaluation of defects/damages of materials such as aerospace, microelectronics, micro-nano structures and the like.
Background
The active infrared thermal wave imaging detection technology provides an effective solution for detecting defects of surface layers and shallow layers of metal materials, composite materials and high polymer materials. However, the conventional active infrared detection method mainly adopts a surface source heat flow excitation and two-dimensional imaging mode to realize detection of the internal characteristics of the near surface layer of the material, only the diffusion process of heat flow along the depth direction is considered, and the plane diffusion process is usually ignored, so that the infrared heat wave imaging detection technology is formed in the subconscious of nondestructive detection personnel, only the approximate position of the defect can be judged, and the illusion of accurate edge morphology of the defect can not be obtained. Although technologies such as dynamic thermal chromatography and the like realize fracture imaging and defect three-dimensional reconstruction, the tomographic detection is still realized by utilizing the one-dimensional diffusion interference characteristic of thermal waves along the depth direction, and the tomographic method has the problems of poor surface defect detection effect, low defect plane size precision and the like. The infrared detection method based on the point/line heat source excitation utilizes the three-dimensional diffusion of heat flow, has a good surface defect detection effect, can realize effective detection of defect edges, but has the defects of low detection efficiency, poor signal-to-noise ratio of internal defect detection and the like. Therefore, the traditional active infrared detection method is difficult to realize the requirements of non-contact online accurate three-dimensional reconstruction detection of defect morphology and scale characteristics; how to combine the heat flow loading advantages of the surface heat source and the point/line heat source, not only ensuring the accurate and efficient detection of depth type and surface type defects, but also fully considering the thermal wave three-dimensional thermal diffusion process, realizing three-dimensional high-resolution fault imaging of the internal state by utilizing the thermal wave diffusion interference and diffraction characteristics, and further being hopeful to solve the bottleneck problem of accurate detection of the infrared thermal wave imaging detection technology.
In the existing research, (patent number: CN 201510124036.5) discloses a microwave step thermal imaging detection and tomography method and system, and a quantitative relation between a characteristic value and depth is established through theoretical analysis and test to quantify the depth of an unknown defect; and realizing tomography in different depth ranges by utilizing the temperature rising rates in different time ranges. The method realizes tomography by utilizing the quantitative relation between the characteristic value and the depth, only considers the diffusion process in the depth direction, and the proposed tomography technology has lower reconstruction precision on the defect edge. Wang Pengwei (patent number: CN 201610841827.4) discloses a nondestructive testing method based on temperature field tomography, which comprises the steps of firstly regarding a testing process as a depth direction heat conduction process of a temperature heat source to obtain a temperature field rigidity coefficient matrix, and then manufacturing different heat insulation protection device models according to different choices of tested parts; and secondly, acquiring the surface temperature of the exposed part of the detected part, selecting different points for determining the surface temperature to be acquired according to the size of the detected part, and reconstructing a three-dimensional image by using a temperature field rigidity coefficient matrix and adopting a generalized vector sampling pattern matching method. The method is still based on tomography in one-dimensional depth direction, and does not consider the three-dimensional diffusion process of heat flow. Liu Junyan et al (patent number: CN 201611054089.5-
CN 201710207453.5) respectively propose a system and a method for detecting the shortened correlated thermal chromatography and the dynamic thermal chromatography in two invention patents, and the two methods only establish the relation between the thermal wave characteristics and the depth direction, and the edge recognition accuracy is poor. The invention provides a laser scanning thermal wave tomography system and a method thereof, which are invented by Chenli (patent number: CN 201310130694.6), wherein the method adopts a high-power laser beam, the surface of a sample is rapidly scanned by a laser scanning device, the pulse thermal excitation is realized, the three-dimensional appearance characterization of the defect is realized by adopting a method similar to a dynamic thermal tomography method, and the method is the same as the dynamic thermal tomography principle in nature. (patent number: CN 201510034897.4) and the like invents a method and a system for detecting and tomography defects by window scanning thermal imaging, wherein a heat source and a thermal imager scan an object to be detected at a fixed speed, and the heat source heats the object to be detected in the scanning process, and the thermal imager records temperature information changing with time after the surface of the object to be detected is heated as original data; reconstructing the original data to obtain a temperature change sequence of each point of the detected object as a detection signal; adopting or generating a specific signal as a reference signal; and performing time domain, frequency domain and cross-correlation processing on the detection signal and the reference signal, extracting a time domain characteristic value, a frequency domain characteristic value, a cross-correlation amplitude characteristic value and a cross-correlation phase characteristic value, and realizing defect detection and tomography. In the method, the time-frequency conversion of the thermal wave signal is considered, and the space domain conversion is not considered, so that the defect edge cannot be effectively identified.
In order to fully utilize the three-dimensional diffusion characteristic of heat flow to realize the three-dimensional accurate detection of defect size/morphology, the invention relates to a photo-thermal three-dimensional characteristic reconstruction method and a photo-thermal three-dimensional characteristic reconstruction system based on laser beam concentration excitation of a phase control array.
Disclosure of Invention
The invention aims to solve the problems in the prior art and provides a photo-thermal three-dimensional characteristic reconstruction system and a reconstruction method based on laser beam concentration excitation of a phase control array. The invention is suitable for the nondestructive testing field of conductive materials such as aerospace, microelectronics, micro-nano structures and the like.
The invention is realized by the following technical scheme, the invention provides a photo-thermal three-dimensional characteristic reconstruction system based on laser bundling excitation of a phase control array, which comprises a computer, a multi-channel data line, a first data acquisition card, a second data acquisition card, a third data acquisition card, a data acquisition card integrator, a multi-channel signal output line, a laser power supply, a cooling water pipe, a refrigerator, an optical fiber bundling, a collimating mirror, a first polaroid, a sample, a two-dimensional mobile station, a second polaroid, a magnetic seat, a focal plane infrared thermal imager, a lifting platform, a BNC data line and an Ethernet line; the computer is provided with three signal ends, one signal output end of the computer is connected with the signal input end of the data acquisition card integrator through a multichannel data line, the second signal input end of the computer is connected with the signal output end of the focal plane thermal infrared imager through an Ethernet line, the third signal output end of the computer is connected with the input end of the focal plane thermal infrared imager through a BNC data line, the first data acquisition card, the second data acquisition card and the third data acquisition card are arranged in the data acquisition card integrator through clamping grooves, the output end of the data acquisition card integrator is connected with the power input end of the laser through a multichannel signal output line, the power modulation change of the laser is controlled, the power input end of the laser is connected with the refrigerator through a cooling water pipe, the power output end of the laser is connected with a laser collimating mirror through an optical fiber bundle, the laser collimating mirror is connected with a first polaroid, a sample piece is arranged on a two-dimensional moving table, an infrared thermal radiation signal radiated by the sample piece is transmitted to the focal plane thermal infrared imager through a second polaroid, and the second polaroid is fixed on the focal plane thermal infrared imager through a lifting table.
The invention also provides a reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the phase control array laser beam bundling excitation, which specifically comprises the following steps:
step one: defining a sample to be detected, and placing the sample on a two-dimensional mobile station;
step two: starting a photo-thermal three-dimensional characteristic reconstruction system based on laser beam bundling excitation of a phase control array;
step three: starting a laser power supply and a refrigerator, so that the working temperature of the laser power supply is maintained to a certain temperature to ensure the normal operation of laser equipment;
step four: starting a focal plane thermal infrared imager, imaging a test sample in real time, starting an array laser to irradiate the sample, and adjusting a two-dimensional moving table to ensure that the irradiation positions of the phased array laser beams are all in the view of the focal plane thermal infrared imager;
step five: the laser beams of the phase control array are distributed in an N multiplied by N matrix, wherein the analog signal output channels of the first data acquisition card, the second data acquisition card and the third data acquisition card are also N multiplied by N, and each laser beam is controlled by an independent analog signal;
step six: extracting phase characteristics of the surface radiation signals by adopting a fractional Fourier correction method based on phased array space frequency modulation signals;
step seven: extracting phase section curves of characteristic images perpendicular to the spatial fluctuation direction, and setting the spatial fluctuation direction as
M is 0,1,2, … M; repeating the steps five, six and seven until m=m stops;
step eight: performing one-dimensional Fourier transform on the obtained section curves in different fluctuation directions, and performing multidirectional reconstruction on the section curves to obtain characteristic images with specific depth;
step nine: varying the different initial frequency f s And a fixed termination frequency f e And (3) obtaining characteristic information of different depths, repeating the steps five to eight, finally obtaining characteristic image sequences of different depths, performing binarization reconstruction on the characteristic images of different depths, and finally obtaining the three-dimensional structure high-precision reconstruction of the test sample.
Further, in the second step, the computer, the first data acquisition card, the second data acquisition card, the third data acquisition card and the data acquisition card integrator are started.
Further, in step three, the laser power supply operating temperature is maintained to 20 ℃.
Further, in the fourth step, the polarization direction of the polarization plate arranged on the laser is consistent with that of the polarization plate in front of the focal plane thermal infrared imager, so that effective filtering of signals is achieved.
Further, in step five, the spatial fluctuation direction is set to be
The first column of laser intensities perpendicular to the direction of the wave motion is then as followsThe modulation of the formula (la),
wherein Q (t) is the intensity of the first column of laser light perpendicular to the direction of fluctuation, Q 0 For peak light intensity, f s For the initial frequency f e Is a termination frequency, and f s ＜f e T is the scanning time;
the wave equation of the second and nth columns of laser beams is,
where n is the nth column of laser beams, and the surface radiation signal obtained in this spatially fluctuating state is S (t).
Further, the phased array space frequency modulation signal based fractional order Fourier correction method specifically comprises the following steps:
wherein K is p Is a fractional Fourier transform kernel function, alpha is a rotation angle, p is a Fourier series, phi FrFT Is the FrFT feature phase.
Further, after step nine, the method further comprises:
step ten: after the test is finished, 5 minutes later, the laser power supply, the water-cooling refrigerator, the data acquisition card and the focal plane thermal infrared imager equipment are turned off.
The invention also provides electronic equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and the processor realizes the steps of the reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the laser beam bundling excitation of the phase control array when executing the computer program.
The invention also provides a computer readable storage medium for storing computer instructions which when executed by a processor implement the steps of the reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the laser beam bundling excitation of the phase control array.
The beneficial effects of the invention are as follows:
(1) Compared with the traditional detection methods such as pulse thermal wave imaging, phase-locked thermal wave imaging, thermal wave radar imaging and the like, the method can fully utilize three-dimensional diffusion of heat flow, accurately reconstruct defects from a two-dimensional angle through changing different spatial fluctuation states of the heat flow, improve detection depth and detection efficiency, and simultaneously realize three-dimensional chromatographic reconstruction of material quantitative characterization and geometric structures, wherein the method aims at realizing high-efficiency accurate detection and three-dimensional characteristic reconstruction aiming at shallow surface defects (< 4mm, diameter/depth ratio > 1.5) of composite materials, metal materials and high-molecular polymers;
(2) The invention discloses a photo-thermal three-dimensional characteristic reconstruction system based on phase control array laser beam concentration excitation, which adopts phase control array laser beam concentration to actively load heat on a sample, wherein single laser beams in the array laser beam concentration can be independently controlled, so that the spatial modulation of heat flow of the sample can be realized, further, the high-precision detection of defect size can be realized, and the defect detection deviation is controlled within 5%.
Drawings
FIG. 1 is a schematic diagram of a photo-thermal three-dimensional feature reconstruction method based on laser beam bundling excitation of a phase control array;
FIG. 2 is a diagram of a photo-thermal three-dimensional feature reconstruction system based on phased array laser beam excitation;
fig. 3 is a schematic diagram of the phased array spatially modulated heat flux distribution and defect reconstruction results.
In the figure: 1-computer, 2-multichannel data line, 3-first data acquisition card, 4-second data acquisition card, 5-third data acquisition card, 6-data acquisition card integrator, 7-multichannel signal output line, 8-laser power supply, 9-cooling water pipe, 10-refrigerator, 11-optical fiber cluster, 12-collimating mirror, 13-first polaroid, 14-sample piece, 15-two-dimensional mobile station, 16-second polaroid, 17-magnetic base, 18-focal plane thermal infrared imager, 19-elevating platform, 20-BNC data line and 21-Ethernet line.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a photo-thermal three-dimensional feature reconstruction method and a photo-thermal three-dimensional feature reconstruction system based on phase control array laser beam concentration excitation, which are used for solving the technical fields of the existing infrared thermal wave chromatography detection technology (dynamic thermal tomography, shortened related thermal tomography, laser scanning thermal wave tomography, window scanning thermal imaging defect detection, tomography and the like) that only utilize a thermal wave to diffuse along a depth one-dimensional direction, and the defect of a heat flow transverse diffusion process is not considered, and the photo-thermal three-dimensional feature reconstruction method (or technology) based on phase control array laser beam concentration excitation fuses the time domain/frequency domain/airspace heat flow modulation, multi-dimensional feature extraction, a thermal wave interference/diffraction characteristic mechanism, thermal wave dispersion characteristics and the like, and can realize high-efficiency accurate detection and three-dimensional feature reconstruction aiming at composite materials, metal materials and high polymer shallow surface defects (< 4mm, and a diameter/depth ratio > 1.5).
The invention provides a photo-thermal three-dimensional characteristic reconstruction method based on phase control array laser beam bundling excitation, and the basic principle of the method is shown in figure 1.Active heat loading is carried out on a test piece by adopting an N multiplied by N array type laser beam bundle, wherein the light intensity of a single laser beam in the array type laser beam bundle can be independently controlled, the array type laser can be controlled to realize space fluctuation change through the multi-channel analog signal output of a data acquisition card (function generator function), and different space fluctuation change directions (namely, change)
Angle) can fully utilize three-dimensional diffusion of heat flow to realize multidirectional accurate characterization of a defect plane. According to the dispersion characteristic of the thermal wave, at a certain fixed angle +.>
And changing different frequencies to extract different depth information of the defect, and finally realizing high-precision reconstruction of the defect scale from a three-dimensional angle.
1-3, the invention provides a photo-thermal three-dimensional characteristic reconstruction system based on laser beam concentration excitation of a phase control array, which comprises a computer, a multi-channel data line, a first data acquisition card, a second data acquisition card, a third data acquisition card, a data acquisition card integrator, a multi-channel signal output line, a laser power supply, a cooling water pipe, a refrigerator, an optical fiber beam concentration, a collimating mirror, a first polaroid, a sample, a two-dimensional mobile station, a second polaroid, a magnetic base, a focal plane thermal infrared imager, a lifting table, a BNC data line and an Ethernet line; the computer is provided with three signal ends, one signal output end of the computer is connected with the signal input end of the data acquisition card integrator through a multichannel data line, the second signal input end of the computer is connected with the signal output end of the focal plane thermal infrared imager through an Ethernet line, the third signal output end of the computer is connected with the input end of the focal plane thermal infrared imager through a BNC data line, the first data acquisition card, the second data acquisition card and the third data acquisition card are arranged in the data acquisition card integrator through clamping grooves, the output end of the data acquisition card integrator is connected with the power input end of the laser through a multichannel signal output line, the power modulation change of the laser is controlled, the power input end of the laser is connected with the refrigerator through a cooling water pipe, the power output end of the laser is connected with a laser collimating mirror through an optical fiber bundle, the laser collimating mirror is connected with a first polaroid, a sample piece is arranged on a two-dimensional moving table, an infrared thermal radiation signal radiated by the sample piece is transmitted to the focal plane thermal infrared imager through a second polaroid, and the second polaroid is fixed on the focal plane thermal infrared imager through a lifting table.
The invention also provides a reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the phase control array laser beam bundling excitation, which specifically comprises the following steps:
step one: defining a sample to be detected, and placing the sample on a two-dimensional mobile station;
step two: starting a photo-thermal three-dimensional characteristic reconstruction system based on laser beam bundling excitation of a phase control array;
step three: starting a laser power supply and a refrigerator, so that the working temperature of the laser power supply is maintained to a certain temperature to ensure the normal operation of laser equipment;
step four: starting a focal plane thermal infrared imager, imaging a test sample in real time, starting an array laser to irradiate the sample, and adjusting a two-dimensional moving table to ensure that the irradiation positions of the phased array laser beams are all in the view of the focal plane thermal infrared imager;
step five: the laser beams of the phase control array are distributed in an N multiplied by N matrix, wherein the analog signal output channels of the first data acquisition card, the second data acquisition card and the third data acquisition card are also N multiplied by N, and each laser beam is controlled by an independent analog signal;
step six: extracting phase characteristics of the surface radiation signals by adopting a fractional Fourier correction method based on phased array space frequency modulation signals;
step seven: extracting phase section curves of characteristic images perpendicular to the spatial fluctuation direction, and setting the spatial fluctuation direction as
M is 0,1,2, … M; repeating the steps five, six and seven until m=m stops;
step eight: performing one-dimensional Fourier transform on the obtained section curves in different fluctuation directions, and performing multidirectional reconstruction on the section curves to obtain characteristic images with specific depth;
step nine: varying the different initial frequency f s And a fixed termination frequency f e And (3) obtaining characteristic information of different depths, repeating the steps five to eight, finally obtaining characteristic image sequences of different depths, performing binarization reconstruction on the characteristic images of different depths, and finally obtaining the three-dimensional structure high-precision reconstruction of the test sample.
In the second step, the computer, the first data acquisition card, the second data acquisition card, the third data acquisition card and the data acquisition card integrator are started.
In step three, the working temperature of the laser power supply is maintained to 20 ℃ so as to ensure the normal operation of the laser device.
In the fourth step, the polarization direction of the polarization plate arranged on the laser is consistent with that of the polarization plate in front of the focal plane thermal infrared imager, so that effective filtering of signals is realized.
In the fifth step, the spatial fluctuation direction is set as
The first column of laser intensities perpendicular to the direction of the fluctuations is modulated as follows,
wherein Q (t) is the intensity of the first column of laser light perpendicular to the direction of fluctuation, Q 0 For peak light intensity, f s For the initial frequency f e Is a termination frequency, and f s ＜f e T is the scanning time;
the wave equation of the second and nth columns of laser beams is,
where n is the nth column of laser beams, and the surface radiation signal obtained in this spatially fluctuating state is S (t).
The phased array space frequency modulation signal based fractional Fourier correction method specifically comprises the following steps:
wherein K is p Is a fractional Fourier transform kernel function, alpha is a rotation angle, p is a Fourier series, phi FrFT Is the FrFT feature phase.
After step nine, the method further comprises:
step ten: after the test is finished, 5 minutes later, the laser power supply, the water-cooling refrigerator, the data acquisition card and the focal plane thermal infrared imager equipment are turned off.
Examples
According to the invention, the computer 1 is provided with three signal ends, one signal output end of the computer 1 is connected with a signal input end of the data acquisition card integrator 6 through the multichannel data wire 2, a second signal input end of the computer 1 is connected with a signal output end of the focal plane infrared thermal imager 18 through the Ethernet wire 21, a third signal output end of the computer 1 is connected with an input end of the focal plane infrared thermal imager 18 through the BNC data wire 20, the first data acquisition card 3, the second data acquisition card 4 and the third data acquisition card 5 are installed in the data acquisition card integrator 6 through clamping grooves, an output end of the data acquisition card integrator 6 is connected with an input end of the laser power supply 8 through the multichannel signal output wire 7, the power modulation change of the laser power supply 8 is controlled, the input end of the laser power supply 8 is connected with the refrigerator 10 through the cooling water pipe 9, an output end of the laser power supply 8 is connected with the laser collimator 12 through the optical fiber bundle 11, the laser collimator 12 is connected with the first polarizer 13 through the threaded connection, the sample 14 is placed on the two-dimensional moving table 15, the sample 14 is placed on the two-dimensional moving table 14, the second polarizer 16 is placed on the focal plane infrared thermal imager 16, and the second polarizer 16 is placed on the focal plane thermal imager 16.
According to the schematic construction system of the photo-thermal three-dimensional characteristic reconstruction system based on the laser beam bundling excitation of the phase control array shown in fig. 2, in the embodiment, the model of the thermal infrared imager 18 is FLIR SC7000, the response wavelength is 3.6-5.2 μm, the maximum frame frequency is 100Hz, the test piece 14 is made of a carbon fiber composite material with a prefabricated flat bottom hole for simulating the debonding defect, the array laser beam bundling is a 7×7 array, and the single laser beam is 5W.
Step one: defining a sample 14 to be detected, and placing the sample 14 on a two-dimensional moving table 15;
step two: starting a photo-thermal three-dimensional characteristic reconstruction system based on laser beam concentration excitation of a phase control array, wherein the method comprises the steps of starting equipment such as a computer 1, a first data acquisition card 3, a second data acquisition card 4, a third data acquisition card 5, a data acquisition card integrator 6 and the like;
step three: starting a laser power supply 8 and a refrigerator 10, so that the working temperature of the laser power supply 8 is maintained to 20 ℃ to ensure the normal operation of laser equipment;
step four: starting a focal plane thermal infrared imager 18, imaging a test sample piece 14 in real time, starting an array laser to irradiate the sample piece 14, and adjusting a two-dimensional moving table 15 to ensure that the irradiation position of a phased array laser beam is all in the view of the focal plane thermal infrared imager 18, wherein the polarization direction of a polarizing plate arranged by the laser is consistent with the polarization direction of a polarizing plate 16 in front of the focal plane thermal infrared imager 18, so that effective filtering of signals is realized;
step five: the laser beams of the phase control array are distributed in a 7×7 matrix, wherein the analog signal output channels of the first data acquisition card 3, the second data acquisition card 4 and the third data acquisition card 5 are also 7×7, each laser beam is controlled by independent analog signals, and at the moment, the spatial fluctuation direction is set to be
(shown in fig. 1), the first column of laser light intensities perpendicular to the direction of the fluctuations is modulated as follows,
wherein Q (t) is the intensity of the first column of laser light perpendicular to the direction of fluctuation, Q 0 For peak light intensity, f s For the initial frequency f e For terminating frequency (f s ＜f e ) T is the scan time. Wherein Q is 0 ＝5000W/m 2 ，f s ＝0.05Hz，f e =0.1 hz, t=20s. The wave equation of the second and nth columns of laser beams is,
where n is the nth column of laser beams. The surface radiation signal S (t) is obtained in this spatially fluctuating state.
Step six: the phase characteristics of the surface radiation signals are extracted by adopting a fractional Fourier correction method based on phased array space frequency modulation signals, the extraction algorithm is that,
wherein K is p Is a fractional Fourier transform kernel function, alpha is a rotation angle, p is a Fourier series, phi FrFT Is FrFT feature phase。
Step seven: and extracting a phase section curve of the characteristic image perpendicular to the spatial fluctuation direction. And set the direction of spatial fluctuation
m is 0,1,2, … 36. Repeating the steps five, six and seven until m=36 is stopped;
step eight: performing one-dimensional Fourier transform on the obtained section curves in different fluctuation directions, and performing multidirectional reconstruction on the section curves to obtain characteristic images with specific depth;
step nine: varying the different initial frequency f s Fixed termination frequency f e Feature information with different depths can be obtained, the steps five to eight are repeated, finally, feature image sequences with different depths can be obtained, binarization reconstruction is carried out on the feature images with different depths, and finally, high-precision reconstruction of the three-dimensional structure of the test sample can be obtained;
step ten: after the test is finished, 5 minutes later, the laser power supply, the water-cooling refrigerator, the data acquisition card, the focal plane thermal infrared imager and other devices are turned off.
Fig. 3 is a schematic diagram showing the distribution of the phased array spatial modulation heat flow and the defect reconstruction result.
The invention also provides electronic equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and the processor realizes the steps of the reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the laser beam bundling excitation of the phase control array when executing the computer program.
The invention also provides a computer readable storage medium for storing computer instructions which when executed by a processor implement the steps of the reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the laser beam bundling excitation of the phase control array.
The memory in embodiments of the present application may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a Read Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous DRAM (SLDRAM), and direct memory bus RAM (DR RAM). It should be noted that the memory of the methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.
In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a high-density digital video disc (digital video disc, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.
In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or by instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in a hardware processor for execution, or in a combination of hardware and software modules in the processor for execution. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method. To avoid repetition, a detailed description is not provided herein.
It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capability. In implementation, the steps of the above method embodiments may be implemented by integrated logic circuits of hardware in a processor or instructions in software form. The processor may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware, in a decoded processor, or in a combination of hardware and software modules in a decoded processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method.
The photo-thermal three-dimensional characteristic reconstruction system and the reconstruction method based on the laser beam bundling excitation of the phase control array provided by the invention are described in detail, and specific examples are applied to illustrate the principle and the implementation mode of the invention, and the description of the above examples is only used for helping to understand the method and the core idea of the invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (9)
1. The reconstruction method of the photo-thermal three-dimensional characteristic reconstruction system based on the laser beam concentration excitation of the phase control array is characterized in that the reconstruction system comprises a computer, a multi-channel data line, a first data acquisition card, a second data acquisition card, a third data acquisition card, a data acquisition card integrator, a multi-channel signal output line, a laser power supply, a cooling water pipe, a refrigerator, an optical fiber beam concentration, a collimating mirror, a first polaroid, a sample piece, a two-dimensional mobile station, a second polaroid, a magnetic base, a focal plane thermal infrared imager, a lifting table, a BNC data line and an Ethernet line; the computer is provided with three signal ends, one signal output end of the computer is connected with the signal input end of the data acquisition card integrator through a multichannel data line, the second signal input end of the computer is connected with the signal output end of the focal plane thermal infrared imager through an Ethernet line, the third signal output end of the computer is connected with the input end of the focal plane thermal infrared imager through a BNC data line, the first data acquisition card, the second data acquisition card and the third data acquisition card are arranged in the data acquisition card integrator through clamping grooves, the output end of the data acquisition card integrator is connected with the power input end of the laser through a multichannel signal output line, the power modulation change of the laser is further controlled, the power input end of the laser is connected with the refrigerator through a cooling water pipe, the power output end of the laser is connected with a laser collimating mirror through an optical fiber bundle, the laser collimating mirror is connected with a first polaroid, a sample piece is arranged on a two-dimensional moving table, an infrared thermal radiation signal radiated by the sample piece is transmitted to the focal plane thermal infrared imager through a second polaroid, and the second polaroid is arranged on the thermal infrared imager through a fixed polarization table;
the reconstruction method specifically comprises the following steps:
step one: defining a sample to be detected, and placing the sample on a two-dimensional mobile station;
step two: starting a photo-thermal three-dimensional characteristic reconstruction system based on laser beam bundling excitation of a phase control array;
step three: starting a laser power supply and a refrigerator, so that the working temperature of the laser power supply is maintained to a certain temperature to ensure the normal operation of laser equipment;
step four: starting a focal plane thermal infrared imager, imaging a test sample in real time, starting an array laser to irradiate the sample, and adjusting a two-dimensional moving table to ensure that the irradiation positions of the phased array laser beams are all in the view of the focal plane thermal infrared imager;
step five: the laser beams of the phase control array are distributed in an N multiplied by N matrix, wherein the analog signal output channels of the first data acquisition card, the second data acquisition card and the third data acquisition card are also N multiplied by N, and each laser beam is controlled by an independent analog signal;
step six: extracting phase characteristics of the surface radiation signals by adopting a fractional Fourier correction method based on phased array space frequency modulation signals;
step seven: extracting phase section curves of characteristic images perpendicular to the spatial fluctuation direction, and setting the spatial fluctuation direction as
M is 0,1,2, … M; repeating the steps five, six and seven until m=m stops;
step eight: performing one-dimensional Fourier transform on the obtained section curves in different fluctuation directions, and performing multidirectional reconstruction on the section curves to obtain characteristic images with specific depth;
step nine: varying the different initial frequency f s And a fixed termination frequency f e And (3) obtaining characteristic information of different depths, repeating the steps five to eight, finally obtaining characteristic image sequences of different depths, performing binarization reconstruction on the characteristic images of different depths, and finally obtaining the three-dimensional structure high-precision reconstruction of the test sample.
2. The method of claim 1, wherein in step two, the computer, the first data acquisition card, the second data acquisition card, the third data acquisition card, and the data acquisition card integrator are turned on.
3. The method of claim 2, wherein in step three, the laser power supply operating temperature is maintained at 20 ℃.
4. The reconstruction method according to claim 1, wherein in step four, the polarization plate arranged by the laser is aligned with the polarization direction of the polarization plate in front of the focal plane thermal infrared imager, thereby achieving effective filtering of the signal.
5. The reconstruction method according to claim 1, wherein in the fifth step, a spatial fluctuation direction is set as
The first column of laser intensities perpendicular to the direction of the fluctuations is modulated as follows,
wherein Q (t) is the intensity of the first column of laser light perpendicular to the direction of fluctuation, Q 0 For peak light intensity, f s For the initial frequency f e Is a termination frequency, and f s ＜f e T is the scanning time;
the wave equation of the second and nth columns of laser beams is,
where n is the nth column of laser beams, and the surface radiation signal obtained in this spatially fluctuating state is S (t).
6. The reconstruction method according to claim 1, wherein the fractional fourier modification method based on phased array spatial frequency modulation signals specifically comprises:
wherein K is p Is a fractional Fourier transform kernel function, alpha is a rotation angle, p is a Fourier series, phi FrFT Is the FrFT feature phase.
7. The reconstruction method according to claim 1, further comprising, after step nine:
step ten: after the test is finished, 5 minutes later, the laser power supply, the water-cooling refrigerator, the data acquisition card and the focal plane thermal infrared imager equipment are turned off.
8. An electronic device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the reconstruction method of any one of claims 1-7 when the computer program is executed.
9. A computer readable storage medium storing computer instructions which, when executed by a processor, implement the steps of the reconstruction method of any one of claims 1-7.
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