Multi-channel damage detection method, device and system based on terahertz signals

Abstract

The invention discloses a multi-channel damage detection method, device and system based on terahertz signals, and the method comprises the steps: taking three paths of terahertz sinusoidal signals as a reference signal, a lossless signal and a to-be-detected signal respectively, carrying out the difference frequency processing of the three paths of signals through a frequency mixer, and obtaining the difference frequency of the three paths of signals; after a low-frequency signal containing damage information is extracted, three-channel signals are subjected to filtering processing and analog-to-digital conversion, and then the signals are subjected to fast Fourier transform (FFT) and phase difference analysis, so that the phase difference change between a to-be-measured object signal and a reference signal and between the to-be-measured object signal and a lossless signal is accurately calculated. Compared with a traditional amplitude detection technology, the method can accurately capture tiny damage features. The multi-channel synchronization system greatly reduces the detection error and improves the real-time performance. According to the method, the detection precision and sensitivity are remarkably improved, and the method has the advantages of being free of radiation, high in safety and high in real-time performance, is particularly suitable for damage detection of complex materials and multi-layer structures and is widely applied to the high-requirement fields such as aerospace and energy pipelines.

Description

Technical Field

[0001] The present invention relates to a multi-channel damage detection method, device and system based on terahertz signals, belonging to the technical field of automation equipment. Background Art

[0002] With the development of modern industrial technology, many key industries such as aerospace, energy pipelines, transportation and construction have put forward higher requirements for the monitoring of material health. In these fields, small damage to materials may lead to serious safety hazards, so it is crucial to develop efficient and accurate non-destructive testing technology. Existing non-destructive testing methods mainly include ultrasonic testing, X-ray testing and infrared testing.

[0003] Existing technologies can meet the needs of non-destructive testing to a certain extent, but there are still problems such as insufficient detection accuracy, low sensitivity and limited scope of application. Especially when facing multi-layer composite materials, complex structures and minor damage, existing detection methods often cannot provide sufficient resolution and reliability.

[0004] In recent years, terahertz detection technology has gradually become a research hotspot in non-destructive testing technology due to its non-ionizing radiation, high penetration, and millimeter or sub-millimeter resolution. Terahertz waves have strong penetration ability and can effectively detect internal defects, especially for multi-layer composite materials, non-metals and complex structures. In addition, terahertz imaging technology does not rely on traditional electromagnetic radiation, so it has higher safety and environmental adaptability.

[0005] However, existing terahertz detection technologies mostly rely on single-channel signal detection and are based on using terahertz signals to calculate the phase of reflected signals on the surface of an object. Although this method has achieved certain results in some applications, it still has a lot of room for improvement in terms of high-precision detection and real-time performance. Single-channel detection is difficult to provide sufficient resolution and information in non-destructive testing of complex structures or multi-layer materials, especially when facing large-scale objects or complex defects, it is difficult to accurately determine their specific location and nature. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-channel damage detection method, device and system based on terahertz signals, which use three terahertz signals as signal sources, one of which is used as a reference signal, and two signals are used as detection signals to pass through a non-destructive object and an object to be tested respectively; through the phase difference between the detection signal and the reference signal, it is determined whether the object to be tested has damage, thereby achieving high-precision, non-destructive detection of internal or surface damage of the object.

[0007] In order to achieve the above objectives / solve the above technical problems, the present invention is implemented by adopting the following technical solutions.

[0008] In one aspect, the present invention provides a multi-channel damage detection method based on terahertz signals, comprising:

[0009] Obtain three terahertz sinusoidal signals;

[0010] Using one of the terahertz sinusoidal signals as a reference signal, using a terahertz sinusoidal signal that has passed through a lossless object as a first detection signal, and using a terahertz sinusoidal signal that has passed through the object to be detected as a second detection signal, performing difference frequency processing on the reference signal, the first detection signal, and the second detection signal into three low-frequency signals, and converting the three low-frequency signals into corresponding three digital signals after amplifying them;

[0011] The reference signal converted into a digital signal is subjected to frequency domain analysis with the first detection signal and the second detection signal, and the phase difference between the two detection signals and the reference signal in the frequency domain is calculated respectively;

[0012] The phase difference between the two detection signals and the reference signal in the frequency domain is converted into a phase difference in the time domain, and the damage result of the object to be tested is determined according to the phase difference in the time domain.

[0013] Furthermore, when the three-way low-frequency signals are amplified, the three-way low-frequency signals are simultaneously converted from single-ended signals to differential signals.

[0014] Furthermore, before the three low-frequency signals are amplified and converted into corresponding three digital signals, the amplified three low-frequency signals are subjected to bandpass filtering.

[0015] Furthermore, the reference signal converted into a digital signal is subjected to frequency domain analysis with the first detection signal and the second detection signal, and the phase difference between the two detection signals and the reference signal is calculated, which specifically includes the following steps:

[0016] Perform fast Fourier transform on the three digital signals respectively, and convert the time domain signals of the corresponding digital signals into complex signals in the frequency domain, specifically including:

[0017] ;

[0018] ;

[0019] ;

[0020] Where n is the nth discrete sampling point of the time domain signal, k is the kth frequency domain point in the frequency domain, j is the imaginary unit, FFT is the fast Fourier transform, and N is the total number of discrete sampling points. is the digital signal of the nth discrete sampling point of the reference signal, is the digital signal of the nth discrete sampling point of the first detection signal, is the digital signal of the nth discrete sampling point of the second detection signal, is the complex signal of the kth frequency domain point of the reference signal, is the complex signal of the kth frequency domain point of the first detection signal, is the complex signal of the kth frequency domain point of the second detection signal, for The amplitude in the frequency domain, for The amplitude in the frequency domain, for The amplitude in the frequency domain, for Phase information in the frequency domain, for Phase information in the frequency domain, for Phase information in the frequency domain;

[0021] Calculate the complex signal amplitude of the three-way digital signal. The specific expression is:

[0022] ;

[0023] ;

[0024] ;

[0025] Among them, Re is the real part information of the corresponding signal in the frequency domain, and Im is the imaginary part information of the corresponding signal in the frequency domain;

[0026] Calculate the complex signal phase information of the three-way digital signal. The specific expression is:

[0027] ;

[0028] ;

[0029] ;

[0030] in, is the argument of the complex signal: is the inverse tangent function;

[0031] Calculate the phase difference between the two detection signals and the reference signal. The specific expression is:

[0032] ;

[0033] ;

[0034] is the phase difference between the first detection signal and the reference signal at the kth frequency domain point; is the phase difference between the second detection signal and the reference signal at the kth frequency domain point.

[0035] Furthermore, the converting the phase difference between the two detection signals and the reference signal into a phase difference in the time domain, and determining the damage result of the object to be tested according to the phase difference in the time domain, specifically includes:

[0036] The frequency domain conversion time domain expression is:

[0037] ;

[0038] ;

[0039] Among them: IFFT is inverse fast Fourier transform; is the phase difference between the first detection signal and the reference signal at the nth discrete sampling point; is the phase difference between the second detection signal and the reference signal at the nth discrete sampling point:

[0040] The phase difference between the first detection signal and the reference signal collected several times at the nth discrete sampling point , and calculate the statistical characteristics and calculate the average value , determine the upper and lower threshold ranges of the average value; if the phase difference between the second detection signal and the reference signal at the nth discrete sampling point If the phase difference information exceeds the upper and lower threshold range of the average value, it can be judged that the object to be tested is damaged. If the phase difference information is between the average value threshold range, it can be judged that the object is intact.

[0041] In a second aspect, the present invention provides a multi-channel damage detection device based on terahertz signals, comprising:

[0042] Signal module: used to obtain three-channel terahertz sinusoidal signals;

[0043] A preprocessing module is used to use one of the terahertz sinusoidal signals as a reference signal, a terahertz sinusoidal signal that has passed through a lossless object as a first detection signal, and a terahertz sinusoidal signal that has passed through the object to be detected as a second detection signal, perform difference frequency processing on the reference signal, the first detection signal, and the second detection signal into three low-frequency signals, and convert the three low-frequency signals into corresponding three digital signals after amplification;

[0044] An analysis module, used to perform frequency domain analysis on the reference signal converted into a digital signal, the first detection signal and the second detection signal, and calculate the phase difference between the two detection signals and the reference signal in the frequency domain;

[0045] The determination module is used to convert the phase difference between the two detection signals and the reference signal in the frequency domain into a phase difference in the time domain, and determine the damage result of the object to be tested according to the phase difference in the time domain.

[0046] In a third aspect, the present invention provides a multi-channel damage detection system based on terahertz signals, comprising:

[0047] Memory, for storing computer programs / instructions;

[0048] The processor is used to execute the computer program / instructions to implement the steps of the multi-channel damage detection method based on terahertz signals.

[0049] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the steps of the above-mentioned multi-channel damage detection method for terahertz signals.

[0050] In a fifth aspect, the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the above-mentioned multi-channel damage detection method for terahertz signals.

[0051] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention is suitable for non-destructive testing of complex structural materials and multi-layer composite materials, taking into account both safety and accuracy, and adopting a multi-channel damage detection scheme that compares the phase difference between a non-destructive object and a damaged object using a three-wave method. By real-time calculation of the fast Fourier transform (FFT) and phase difference analysis of the signal, non-destructive testing of complex structural materials and multi-layer composite materials is achieved, and the signal phase changes caused by slight damage to the object to be tested can be accurately captured, so as to determine whether the object is damaged and the degree of damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Shown is a flow chart of the calculation method of the present invention;

[0053] Figure 2 Shown is a system schematic diagram of the present invention;

[0054] Figure 3 Shown is a flow chart of the application method of the present invention;

[0055] Figure 4 Shown is a structural block diagram of the present invention;

[0056] Among them: 1. Terahertz signal generator, 2. Mixer, 3. Power amplifier, 4. Matching filter, 5. Analog-to-digital converter, 6. FPGA digital processor, 7. Host computer. DETAILED DESCRIPTION

[0057] It should be noted that:

[0058] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0059] The term "and / or" is only a description of the association relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " generally indicates that the related objects are in an "or" relationship.

[0060] Example 1

[0061] like Figure 1~2 An embodiment shown in the figure provides a multi-channel damage detection method based on terahertz signals, comprising:

[0062] Get three terahertz sinusoidal signals. The initial signal of the terahertz sinusoidal signal is set to , the amplitude is set to 1;

[0063] One of the terahertz sinusoidal signals is used as the reference signal , use the terahertz sinusoidal signal passing through the lossless object as the first detection signal , the terahertz sinusoidal signal after passing through the object to be tested is used as the second detection signal , performing difference frequency processing on the reference signal, the first detection signal (lossless signal) and the second detection signal (signal to be measured) into three low-frequency signals, and converting the three low-frequency signals into corresponding three digital signals after amplifying them;

[0064] The reference signal converted into a digital signal is subjected to frequency domain analysis with the first detection signal and the second detection signal, and the phase difference between the two detection signals and the reference signal in the frequency domain is calculated respectively;

[0065] The phase difference between the two detection signals and the reference signal in the frequency domain is converted into a phase difference in the time domain, and the damage result of the object to be tested is determined according to the phase difference in the time domain.

[0066] Furthermore, when the three-way low-frequency signals are amplified, the three-way low-frequency signals are simultaneously converted from single-ended signals to differential signals.

[0067] Furthermore, before the three low-frequency signals are amplified and converted into corresponding three digital signals, the amplified three low-frequency signals are subjected to bandpass filtering.

[0068] Furthermore, the reference signal converted into a digital signal is subjected to frequency domain analysis with the first detection signal and the second detection signal, and the phase difference between the two detection signals and the reference signal is calculated, which specifically includes the following steps:

[0069] Perform fast Fourier transform on the three digital signals respectively, and convert the time domain signals of the corresponding digital signals into complex signals in the frequency domain, specifically including:

[0070] ;

[0071] ;

[0072] ;

[0073] Where n is the nth discrete sampling point of the time domain signal, k is the kth frequency domain point in the frequency domain, j is the imaginary unit, FFT is the fast Fourier transform, and N is the total number of discrete sampling points. is the digital signal of the nth discrete sampling point of the reference signal, is the digital signal of the nth discrete sampling point of the first detection signal, is the digital signal of the nth discrete sampling point of the second detection signal, is the complex signal of the kth frequency domain point of the reference signal, is the complex signal of the kth frequency domain point of the first detection signal, is the complex signal of the kth frequency domain point of the second detection signal, for The amplitude in the frequency domain, for The amplitude in the frequency domain, for The amplitude in the frequency domain, for Phase information in the frequency domain, for Phase information in the frequency domain, for Phase information in the frequency domain;

[0074] Calculate the complex signal amplitude of the three-way digital signal. The specific expression is:

[0075] ;

[0076] ;

[0077] ;

[0078] Among them, Re is the real part information of the corresponding signal in the frequency domain, and Im is the imaginary part information of the corresponding signal in the frequency domain;

[0079] Calculate the complex signal phase information of the three-way digital signal. The specific expression is:

[0080] ;

[0081] ;

[0082] ;

[0083] in, is the argument of the complex signal: is the inverse tangent function;

[0084] Calculate the phase difference between the two detection signals and the reference signal. The specific expression is:

[0085] ;

[0086] ;

[0087] is the phase difference between the first detection signal and the reference signal at the kth frequency domain point; is the phase difference between the second detection signal and the reference signal at the kth frequency domain point.

[0088] Furthermore, the converting the phase difference between the two detection signals and the reference signal into a phase difference in the time domain, and determining the damage result of the object to be tested according to the phase difference in the time domain, specifically includes:

[0089] The frequency domain conversion time domain expression is:

[0090] ;

[0091] ;

[0092] Among them: IFFT is inverse fast Fourier transform; is the phase difference between the first detection signal and the reference signal at the nth discrete sampling point; is the phase difference between the second detection signal and the reference signal at the nth discrete sampling point:

[0093] The phase difference between the first detection signal and the reference signal collected several times at the nth discrete sampling point , and calculate the statistical characteristics and calculate the average value , determine the upper and lower threshold ranges of the average value; if the phase difference between the second detection signal and the reference signal at the nth discrete sampling point If the phase difference information exceeds the upper and lower threshold range of the average value, it can be judged that the object to be tested is damaged. If the phase difference information is between the average value threshold range, it can be judged that the object is intact.

[0094] Example 2

[0095] This embodiment provides a multi-channel damage detection device based on terahertz signals, including:

[0096] Signal module: used to obtain three-channel terahertz sinusoidal signals;

[0097] A preprocessing module is used to use one of the terahertz sinusoidal signals as a reference signal, a terahertz sinusoidal signal that has passed through a lossless object as a first detection signal (lossless signal), and a terahertz sinusoidal signal that has passed through the object to be detected as a second detection signal (detected signal), perform difference frequency processing on the reference signal, the first detection signal, and the second detection signal into three low-frequency signals, and convert the three low-frequency signals into corresponding three digital signals after amplification;

[0098] An analysis module, used to perform frequency domain analysis on the reference signal converted into a digital signal, the first detection signal and the second detection signal, and calculate the phase difference between the two detection signals and the reference signal in the frequency domain;

[0099] The determination module is used to convert the phase difference between the two detection signals and the reference signal in the frequency domain into a phase difference in the time domain, and determine the damage result of the object to be tested according to the phase difference in the time domain.

[0100] like Figure 3~4 In the embodiment shown, the signal module uses a terahertz generator, the pre-processing module uses a mixer, and the analysis module uses an FPGA processor.

[0101] The multi-channel damage detection device comprises a terahertz signal generator 1, a mixer 2, a power amplifier 3, a matching filter 4, an analog-to-digital converter 5, an FPGA digital processor 6 and a host computer 7 which are connected in sequence;

[0102] The terahertz signal generator 1 is used to emit three terahertz sinusoidal signals, the frequency range of the three terahertz sinusoidal signals is 0.1T~10THz, the first sinusoidal signal of the three sinusoidal signals is selected as the reference signal to directly enter the mixer 2, the second sinusoidal signal is the first detection signal (lossless signal) to enter the mixer 2 after passing through the lossless object, and the third sinusoidal signal is the second detection signal (signal to be measured) to enter the mixer 2 after passing through the object to be measured. The initial frequencies of the three terahertz signals are selected according to the material properties of the object to be measured to ensure that the signals can penetrate the material and produce a measurable phase difference under different structures;

[0103] The mixer 2 receives the reference signal sent by the terahertz signal generator 1, the first detection signal after passing through the damage-free object, and the second detection signal after passing through the object to be tested, and performs difference frequency processing to mix the three sinusoidal signals to generate a low-frequency signal containing damage information;

[0104] The power amplifier 3 receives the sinusoidal signal output by the mixer 2 and completes signal amplification and conversion of the single-ended signal to the differential signal. The power amplifier 3 is connected to the mixer via an SMA interface, performs power amplification on the difference frequency signal, and completes conversion of the single-ended signal to the differential signal to meet the input requirements of the analog-to-digital converter;

[0105] The matched filter 4 receives the output signal of the power amplifier 3 and filters out high-frequency and unnecessary signal components in the signal, retaining a clean and effective signal, with a center frequency matching the difference frequency signal frequency and a bandwidth range of 100kHz to 5MHz;

[0106] The analog-to-digital converter 5 receives the analog signal output by the matched filter 4 and completes the conversion from the analog signal to the digital signal, ensures the signal integrity through a high sampling rate (80MSPS), and provides high-quality input for subsequent digital processing;

[0107] The FPGA digital processor 6 receives the digital signal of the analog-to-digital converter 5, performs fast Fourier transform to calculate the phase difference between the first detection signal passing through the intact object and the reference signal, and the phase difference between the second detection signal passing through the object to be tested and the reference signal, and then outputs the signal to the host computer 7; the FPGA digital processor 6 has a built-in fast Fourier transform (FFT) module and a phase difference calculation module, which can perform frequency domain conversion on the three-channel digital signal and calculate the phase difference information in real time with an efficient parallel computing architecture, and extract key information reflecting the damage characteristics of the object to be tested by analyzing the phase difference between the reference signal and the two-channel detection signals;

[0108] The host computer 7 receives the calculation results of the FPGA digital signal processor 6 and displays them visually. It determines whether the object to be tested is damaged based on the visualization results. It is connected to the FPGA digital processor 6 through a data interface, receives and visualizes the phase difference information, and combines the dynamically changing phase difference curve and specific values ​​to provide users with a clear basis for judging the damage status of the object to be tested.

[0109] The working principle of this embodiment is as follows: three terahertz signals are used to pass through a lossless object, an object to be tested, and directly enter a mixer. After passing through a lossless object, the output phase difference will produce a slight change due to the material characteristics of the object, and the phase of the signal after passing through the lossless object is subtracted from the phase of the signal directly entering the mixer; when passing through a damaged object, the internal structure changes due to material damage, which will cause the phase of the input signal to change. At this time, the phase of the signal passing through the damaged object is subtracted from the phase of the signal directly entering the mixer; the result of the phase difference calculation after passing through the lossless object is compared with the result of the phase difference calculation after passing through the damaged object. If the result exceeds the threshold, it can be determined that the inside of the object to be tested is damaged.

[0110] Example 3

[0111] This embodiment provides a multi-channel damage detection system based on terahertz signals, including:

[0112] Memory, for storing computer programs / instructions;

[0113] The processor is used to execute the computer program / instructions to implement the steps of the multi-channel damage detection method based on terahertz signals.

[0114] Example 4

[0115] This embodiment provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the multi-channel damage detection method for terahertz signals are implemented.

[0116] Example 5

[0117] This embodiment provides a computer program product, including a computer program / instruction, which implements the steps of the above-mentioned multi-channel damage detection method for terahertz signals when executed by a processor.

[0118] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A multi-channel damage detection method based on terahertz signals, characterized in that: include: Obtain three terahertz sinusoidal signals; Using one of the terahertz sinusoidal signals as a reference signal, using a terahertz sinusoidal signal that has passed through a lossless object as a first detection signal, and using a terahertz sinusoidal signal that has passed through the object to be detected as a second detection signal, performing difference frequency processing on the reference signal, the first detection signal, and the second detection signal into three low-frequency signals, and converting the three low-frequency signals into corresponding three digital signals after amplifying them; The reference signal converted into a digital signal is subjected to frequency domain analysis with the first detection signal and the second detection signal, and the phase difference between the two detection signals and the reference signal in the frequency domain is calculated respectively; The phase difference between the two detection signals and the reference signal in the frequency domain is converted into a phase difference in the time domain, and the damage result of the object to be tested is determined according to the phase difference in the time domain.

2. The multi-channel damage detection method based on terahertz signals according to claim 1 is characterized in that: When the three-way low-frequency signals are amplified, the three-way low-frequency signals are simultaneously converted from single-ended signals to differential signals.

3. The multi-channel damage detection method based on terahertz signals according to claim 1 is characterized in that: Before the three-way low-frequency signals are amplified and converted into corresponding three-way digital signals, the amplified three-way low-frequency signals are subjected to bandpass filtering.

4. The multi-channel damage detection method based on terahertz signals according to claim 1 is characterized in that: The reference signal converted into a digital signal is subjected to frequency domain analysis with the first detection signal and the second detection signal respectively, and the phase difference between the two detection signals and the reference signal is respectively calculated, specifically comprising the following steps: Perform fast Fourier transform on the three digital signals respectively, and convert the time domain signals of the corresponding digital signals into complex signals in the frequency domain, specifically including: ； ； ； Where n is the nth discrete sampling point of the time domain signal, k is the kth frequency domain point in the frequency domain, j is the imaginary unit, FFT is the fast Fourier transform, and N is the total number of discrete sampling points. is the digital signal of the nth discrete sampling point of the reference signal, is the digital signal of the nth discrete sampling point of the first detection signal, is the digital signal of the nth discrete sampling point of the second detection signal, is the complex signal of the kth frequency domain point of the reference signal, is the complex signal of the kth frequency domain point of the first detection signal, is the complex signal of the kth frequency domain point of the second detection signal, for The amplitude in the frequency domain, for The amplitude in the frequency domain, for The amplitude in the frequency domain, for Phase information in the frequency domain, for Phase information in the frequency domain, for Phase information in the frequency domain; Calculate the complex signal amplitude of the three-way digital signal. The specific expression is: ； ； ； Among them, Re is the real part information of the corresponding signal in the frequency domain, and Im is the imaginary part information of the corresponding signal in the frequency domain; Calculate the complex signal phase information of the three-way digital signal. The specific expression is: ； ； ； in, is the argument of the complex signal: is the inverse tangent function; Calculate the phase difference between the two detection signals and the reference signal. The specific expression is: ； ； is the phase difference between the first detection signal and the reference signal at the kth frequency domain point; is the phase difference between the second detection signal and the reference signal at the kth frequency domain point.

5. The multi-channel damage detection method based on terahertz signals according to claim 4 is characterized in that: The converting the phase difference between the two detection signals and the reference signal into a phase difference in the time domain, and determining the damage result of the object to be tested according to the phase difference in the time domain, specifically includes: The frequency domain conversion time domain expression is: ； ； Among them: IFFT is inverse fast Fourier transform; is the phase difference between the first detection signal and the reference signal at the nth discrete sampling point; is the phase difference between the second detection signal and the reference signal at the nth discrete sampling point: The phase difference between the first detection signal and the reference signal collected several times at the nth discrete sampling point , and calculate the statistical characteristics and calculate the average value , determine the upper and lower threshold ranges of the average value; if the phase difference between the second detection signal and the reference signal at the nth discrete sampling point If the phase difference information exceeds the upper and lower threshold range of the average value, it can be judged that the object to be tested is damaged. If the phase difference information is between the average value threshold range, it can be judged that the object is intact.

6. A multi-channel damage detection device based on terahertz signals, characterized in that: include: Signal module: used to obtain three-channel terahertz sinusoidal signals; A preprocessing module is used to use one of the terahertz sinusoidal signals as a reference signal, a terahertz sinusoidal signal that has passed through a lossless object as a first detection signal, and a terahertz sinusoidal signal that has passed through the object to be detected as a second detection signal, perform difference frequency processing on the reference signal, the first detection signal, and the second detection signal into three low-frequency signals, and convert the three low-frequency signals into corresponding three digital signals after amplification; An analysis module, used to perform frequency domain analysis on the reference signal converted into a digital signal, the first detection signal and the second detection signal, and calculate the phase difference between the two detection signals and the reference signal in the frequency domain; The determination module is used to convert the phase difference between the two detection signals and the reference signal in the frequency domain into a phase difference in the time domain, and determine the damage result of the object to be tested according to the phase difference in the time domain.

7. A multi-channel damage detection system based on terahertz signals, characterized in that: include: Memory, for storing computer programs / instructions; A processor is used to execute the computer program / instructions to implement the steps of the multi-channel damage detection method for terahertz signals according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the steps of the multi-channel damage detection method for terahertz signals described in any one of claims 1 to 5 are implemented.

9. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the multi-channel damage detection method for terahertz signals described in any one of claims 1 to 5 are implemented.

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