Adaptive compensation method, device and equipment for terahertz transmission dispersion

Abstract

The application provides a terahertz transmission dispersion adaptive compensation method, device and equipment, which can be applied to the terahertz technical field. The adaptive compensation method comprises the following steps: obtaining an original wrapped phase difference between a first frequency spectrum corresponding to a reference pulse and a second frequency spectrum corresponding to a transmission pulse according to the first frequency spectrum and the second frequency spectrum; performing phase unwrapping on the wrapped phase difference to obtain a continuous phase difference curve about an angular frequency; performing polynomial fitting on the phase difference about the angular frequency based on a predetermined central angular frequency and an adjustable order to extract a dispersion parameter; constructing a filter based on the dispersion parameter and an adjustable compensation strength factor; applying the filter to the second frequency spectrum to obtain a third frequency spectrum, and then obtaining a compensated transmission pulse in the time domain; and adjusting at least one of the adjustable order and the adjustable compensation strength factor according to the compensated transmission pulse and the reference pulse until a predetermined condition is met, and obtaining an adaptive compensated transmission pulse.

Description

Technical Field

[0001] At least one embodiment of this application relates to the field of terahertz technology, and more specifically to an adaptive compensation method, apparatus and device for terahertz transmission dispersion. Background Technology

[0002] In the field of integrated optoelectronics, planar integrated waveguides, metal wire waveguides, dielectric waveguides, and other structures provide pathways for on-chip transmission and processing of terahertz signals. In the field of precision non-destructive testing, terahertz pulses, with their advantages of non-invasiveness, non-contact, and non-ionization, can perform highly sensitive detection of the internal properties of multilayer composite materials such as ceramic substrates and coatings. However, in both of these application systems, dispersion remains a physical bottleneck restricting the improvement of system performance. Summary of the Invention

[0003] According to a first aspect of this application, an adaptive compensation method for terahertz transmission dispersion is provided. The adaptive compensation method includes: transforming a time-domain reference pulse and a transmission pulse to the frequency domain to obtain a first spectrum and a second spectrum, respectively; wherein the reference pulse is a terahertz pulse signal returned when a probe contacts an object under test, and the transmission pulse is a terahertz pulse signal returned at a fault point on the object under test; obtaining a phase difference with respect to angular frequency based on the first spectrum and the second spectrum; and performing polynomial fitting on the phase difference with respect to angular frequency based on a predetermined center angular frequency and an adjustable order to extract dispersion parameters. Based on the aforementioned dispersion parameters and an adjustable compensation intensity factor, a filter is constructed. The phase response of the filter in the frequency domain is set to at least partially compensate for the dispersion terms in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation. The filter is applied to the second spectrum to obtain a third spectrum. The third spectrum is transformed to the time domain to obtain a compensated transmission pulse. Based on the compensated transmission pulse and the reference pulse, at least one of the adjustable order and the adjustable compensation intensity factor is adjusted until a predetermined condition is met to obtain an adaptively compensated transmission pulse.

[0004] The second aspect of this application provides an adaptive compensation device for terahertz transmission dispersion. The adaptive compensation device includes: a first conversion module for converting a time-domain reference pulse and a transmission pulse to the frequency domain, obtaining a first spectrum and a second spectrum respectively; wherein the reference pulse is a terahertz pulse signal returned when a probe contacts an object under test, and the transmission pulse is a terahertz pulse signal returned at a fault point on the object under test; a obtaining module for obtaining a phase difference with respect to angular frequency based on the first spectrum and the second spectrum; an extraction module for performing polynomial fitting on the phase difference with respect to angular frequency based on a predetermined center angular frequency and an adjustable order to extract dispersion parameters; and a construction module. A filter is constructed based on the aforementioned dispersion parameters and an adjustable compensation intensity factor, wherein the phase response of the filter in the frequency domain is set to at least partially compensate for the dispersion terms in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation; a compensation module is used to apply the filter to the aforementioned second spectrum to obtain a third spectrum; a second conversion module is used to transform the aforementioned third spectrum to the time domain to obtain a compensated transmission pulse; and an adjustment module is used to adjust at least one of the adjustable order and the adjustable compensation intensity factor according to the aforementioned compensated transmission pulse and the aforementioned reference pulse until a predetermined condition is met to obtain an adaptively compensated transmission pulse.

[0005] A third aspect of this application provides an electronic device comprising: one or more processors; and a memory for storing one or more computer programs, wherein the one or more processors execute the one or more computer programs to implement the steps of the method described above.

[0006] A fourth aspect of this application also provides a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the steps of the above-described method.

[0007] The fifth aspect of this application also provides a computer program product, including a computer program or instructions that, when executed by a processor, implement the steps of the above-described method.

[0008] According to embodiments of this application, when a terahertz pulse propagates in a medium, different frequency components experience different phase delays due to dispersion effects, resulting in pulse broadening and distortion. Based on the phase difference between the reference pulse and the transmitted pulse in the frequency domain with respect to angular frequency, dispersion parameters can be extracted using a polynomial-fitted curve corresponding to the phase difference with respect to angular frequency. A frequency domain filter with opposite phase responses is constructed based on these dispersion parameters, and an adjustable compensation intensity factor is introduced to flexibly adjust the compensation strength. Applying the filter to the second spectrum of the transmitted pulse cancels out the phase distortion introduced by dispersion in the frequency domain, obtaining a time-domain compensated transmitted pulse. Finally, based on the degree of pulse width recovery and waveform similarity, the adjustable order and adjustable compensation intensity factor are adjusted, iteratively optimizing the filter to ultimately achieve adaptive, high-order terahertz dispersion compensation. This improves the resolution and measurement accuracy of the terahertz detection system, enabling high-performance terahertz transmission and detection. Attached Figure Description

[0009] The above-mentioned contents, other objects, features and advantages of this application will become clearer from the following description of embodiments of this application with reference to the accompanying drawings.

[0010] Figure 1 The diagram illustrates an application scenario of the adaptive compensation method, apparatus, and device for terahertz transmission dispersion according to embodiments of this application.

[0011] Figure 2 A flowchart of an adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application is shown.

[0012] Figure 3 A flowchart of an adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application is shown.

[0013] Figure 4 A structural block diagram of an adaptive compensation device for terahertz transmission dispersion according to an embodiment of this application is shown.

[0014] Figure 5 A block diagram of an electronic device suitable for implementing an adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application is shown. Detailed Implementation

[0015] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0016] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0017] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0018] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0019] Terahertz waves lie between microwaves and infrared radiation, possessing both strong penetrating power and high resolution while maintaining the safety of non-ionizing radiation. They have irreplaceable potential in integrated optoelectronics and precision non-destructive testing. However, the performance of their application systems depends on the transmission quality of the terahertz signal.

[0020] For waveguide transmission, terahertz dispersion causes time-domain broadening, waveform distortion, and mode distortion of ultrashort pulses during propagation, which not only limits the effective bandwidth and transmission distance of communication systems but also poses difficulties for pulse-shaping-based signal processing. For terahertz nondestructive testing systems, the dispersion effect causes echo pulses reflected from defects at different depths or adjacent defects to overlap and merge, reducing the system's ability to resolve and locate minute defects, thin structures, or closely adjacent interfaces.

[0021] While research on terahertz dispersion compensation has developed into a multi-dimensional and multi-layered technical system, ranging from deterministic compensation based on prior physical models to adaptive reconstruction based on data-driven dictionary learning, and then to model-algorithm fusion for specific materials, ultimately covering the nonlinear correction of the system itself, most algorithms rely on precise knowledge of the material's dispersion characteristics. This limitation is significant when dealing with unknown or non-uniform materials, and real-time, robust compensation under complex conditions remains a technical challenge that needs to be addressed.

[0022] Therefore, there is an urgent need for a highly targeted and efficient dispersion compensation method for terahertz pulses during transmission, which is essential for achieving high-performance terahertz transmission and detection.

[0023] This application provides an adaptive compensation method for terahertz transmission dispersion. The method transforms a time-domain reference pulse and a transmission pulse to the frequency domain, obtaining a first spectrum and a second spectrum, respectively. The reference pulse is a terahertz pulse signal returned when a probe contacts the object under test, and the transmission pulse is a terahertz pulse signal returned at a fault point on the object under test. Based on the first and second spectra, a phase difference with respect to angular frequency is obtained. A polynomial fit is performed on the phase difference with respect to angular frequency based on a predetermined center angular frequency and an adjustable order to extract dispersion parameters. Based on the dispersion parameters and an adjustable compensation intensity factor, a filter is constructed. The phase response of the filter in the frequency domain is set to at least partially compensate for the dispersion terms in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation. The filter is applied to the second spectrum to obtain a third spectrum. The third spectrum is transformed to the time domain to obtain a compensated transmission pulse. Based on the compensated transmission pulse and the reference pulse, at least one of the adjustable order and the adjustable compensation intensity factor is adjusted until a predetermined condition is met, resulting in an adaptively compensated transmission pulse.

[0024] Figure 1 The diagram illustrates an application scenario of the adaptive compensation method, apparatus, and device for terahertz transmission dispersion according to embodiments of this application.

[0025] like Figure 1 As shown, application scenario 100 according to this embodiment may include an item under test 101, a probe 102, a signal generating device 103, a network 104, and a server 105. The network 104 serves as a medium for providing a communication link between the probe 102 and the server 105. The network 104 may include various connection types, such as wired or wireless communication links, or fiber optic cables, etc.

[0026] A terahertz pulse signal is generated by the signal generator 103 and emitted to the object under test 101 via the probe 102. The probe 102 can detect the emitted terahertz pulse signal, such as the pulse reflected back by the object under test 101. The probe 102 interacts with the server 105 via the network 104.

[0027] Server 105 can be a server that provides various services and can analyze and process the received data.

[0028] It should be noted that the terahertz pulse signal enhancement method based on time-domain reflectometry provided in this application embodiment can generally be executed by server 105. Correspondingly, the adaptive compensation device for terahertz transmission dispersion provided in this application embodiment can generally be set in server 105.

[0029] The following will be based on Figure 1The scenario described herein is illustrated in detail with reference to the adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application.

[0030] Figure 2 A flowchart of an adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application is shown.

[0031] like Figure 2 As shown, in operation S210, the reference pulse and transmission pulse in the time domain are transformed to the frequency domain to obtain the first spectrum and the second spectrum, respectively. For example, a Fourier transform can be used to transform the reference pulse and transmission pulse in the time domain to the frequency domain to obtain the first spectrum and the second spectrum, respectively.

[0032] In operation S220, the phase difference with respect to angular frequency is obtained based on the first spectrum and the second spectrum.

[0033] The probes in a terahertz detection system can be waveguide probes or coaxial probes. Used for transmitting and receiving terahertz pulse signals, they possess strong directionality, allowing the terahertz pulse signal to be transmitted from a waveguide to the object under test (DUT) or vice versa. Probes can also be optical guide probes, directly utilizing the principle of terahertz optical guide antennas for measurement. The DUT includes integrated circuits. Integrated circuits may have defects during manufacturing, such as design flaws, material defects, process defects, and packaging defects, leading to malfunctions and inoperability. Terahertz pulse signals are electromagnetic waves in the range of 0.1 THz to 10 THz, with wavelengths between microwaves and infrared light.

[0034] The terahertz detection system can emit terahertz pulse signals through a probe. The reference pulse is the terahertz pulse signal returned when the probe contacts the object under test, and the transmission pulse is the terahertz pulse signal returned at the fault point of the object under test.

[0035] The transmitted pulse travels a longer distance in the medium compared to the reference pulse, and therefore arrives later in the return time. The buffer is based on the terahertz time-domain signal `singal_full(t)` acquired by the terahertz detection system, where `t` represents time. Based on the temporal relationship between the reference and transmitted pulses, they can be identified from the terahertz time-domain signal. The reference pulse `singal_ref(t)` and the transmitted pulse `singal_tran(t)` are extracted from the terahertz time-domain signal to ensure that the time windows of the reference and transmitted pulses are aligned and contain the complete pulse waveform.

[0036] When using a terahertz detection system to detect objects, the transmitted terahertz pulses undergo broadening and distortion due to the dispersive properties of the medium, leading to decreased time-domain resolution and blurred features. Dispersion is one factor contributing to the time-domain broadening of ultrashort terahertz pulses during propagation; the transmitted pulse has a wider pulse width than the reference pulse. According to an embodiment, a Fourier transform can be performed on the reference and transmitted pulses. To more conveniently examine the phase term, a first spectrum E_ref(ω) and a second spectrum E_tran(ω) in complex spectral form can be used, where ω is the angular frequency. The phase angle information of the first spectrum E_ref(ω) and the second spectrum E_tran(ω) can be extracted to obtain the phase difference between the first spectrum E_ref(ω) and the second spectrum E_tran(ω) with respect to the angular frequency. This phase difference with respect to the angular frequency reflects the phase distortion caused by dispersion. The phase difference between the first spectrum and the second spectrum can be a continuous curve with respect to angular frequency ω (or frequency f), or it can be a discrete phase difference sequence with respect to several discrete angular frequencies ω (or frequency f) (e.g., obtained by sampling the phase difference at several discrete angular frequencies ω).

[0037] In operation S230, polynomial fitting is performed on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order to extract the dispersion parameters.

[0038] The predetermined center angular frequency can be taken as the center frequency or peak frequency of the first spectrum, and the adjustable order indicates the order of the polynomial to be fitted. For example, the adjustable order can be 2, corresponding to a second-order dispersion model. Based on the second-order dispersion model, a polynomial fitting is performed on the curve corresponding to the phase difference with respect to the angular frequency. Dispersion parameters, including group delay, group velocity dispersion coefficient, etc., can be extracted from the fitted polynomial. Alternatively, the adjustable order can be 3, corresponding to a third-order dispersion model. The order can be adjusted according to actual needs.

[0039] In operation S240, a filter is constructed based on the dispersion parameters and an adjustable compensation intensity factor. The phase response of the filter in the frequency domain is set to at least partially compensate for the dispersion terms in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation.

[0040] The dispersion parameter is derived from the phase difference with respect to the angular frequency and contains phase difference information. Based on the dispersion parameter, the opposite phase of each frequency component can be determined. The compensation intensity can be flexibly adjusted based on the adjustable compensation intensity factor, thereby constructing a frequency domain filter with opposite phase response.

[0041] By operating S250, the filter is applied to the second spectrum to obtain the third spectrum.

[0042] In operation S260, the third spectrum is transformed to the time domain to obtain the compensated transmission pulse. For example, an inverse Fourier transform can be used to transform the third spectrum to the time domain.

[0043] In operation S270, based on the compensated transmission pulse and the reference pulse, at least one of the adjustable order and the adjustable compensation intensity factor is adjusted until a predetermined condition is met to obtain the adaptively compensated transmission pulse.

[0044] The predetermined conditions can be set based on the degree of pulse width recovery of the compensated transmitted pulse, or the waveform similarity between the compensated transmitted pulse and the reference pulse.

[0045] According to embodiments of this application, when a terahertz pulse propagates in a medium, different frequency components experience different phase delays due to dispersion effects, resulting in pulse broadening and distortion. Based on the phase difference between the reference pulse and the transmitted pulse in the frequency domain with respect to angular frequency, dispersion parameters can be extracted using a polynomial-fitted curve corresponding to the phase difference with respect to angular frequency. A frequency domain filter with opposite phase responses is constructed based on these dispersion parameters, and an adjustable compensation intensity factor is introduced to flexibly adjust the compensation strength. Applying the filter to the second spectrum of the transmitted pulse cancels out the phase distortion introduced by dispersion in the frequency domain, obtaining a time-domain compensated transmitted pulse. Finally, based on the degree of pulse width recovery and waveform similarity, the adjustable order and adjustable compensation intensity factor are adjusted, iteratively optimizing the filter to ultimately achieve adaptive, high-order terahertz dispersion compensation. This improves the resolution and measurement accuracy of the terahertz detection system, enabling high-performance terahertz transmission and detection.

[0046] In one example, the buffer is based on the complete terahertz time-domain signal `singal_full(t)` acquired by the terahertz detection system, recording time `t` and sampling interval `Δt`. The reference pulse `singal_ref(t)` and the transmission pulse `singal_tran(t)` are extracted from the terahertz time-domain signal, respectively.

[0047] Determine the pulse widths of the reference pulse and the transmitted pulse. The pulse width of the reference pulse is defined as `width_ref`, which is the length of the time interval from when the signal amplitude of the reference pulse first exceeds the peak value α to when it last exceeds the peak value α. The pulse width of the transmitted pulse is defined as `width_tran`, which is the length of the time interval from when the signal amplitude of the transmitted pulse first exceeds the peak value α to when it last exceeds the peak value α. The peak value α represents α multiplied by the peak value. In the standard calculation mode, a threshold coefficient α = 0.1 can be set, while in the calculation of the full width at half maximum (FWHM), a threshold coefficient α = 0.5 can be set.

[0048] Determine the original pulse broadening factor β_tran of the transmitted pulse relative to the reference pulse:

[0049] β_tran=width_tran / width_ref(1).

[0050] The pulse broadening factor of the compensated transmitted pulse relative to the reference pulse can be compared with the original pulse broadening factor of the transmitted pulse relative to the reference pulse.

[0051] According to an embodiment of this application, obtaining the phase difference with respect to angular frequency based on a first spectrum and a second spectrum includes: determining a discrete sequence of the original wrapped phase difference with respect to angular frequency based on the phase angle of the first spectrum and the second spectrum; and performing phase unwrapping on the discrete sequence using the adjacent point difference method to obtain the phase difference with respect to angular frequency.

[0052] In one example, a Fast Fourier Transform (FFT) is performed on the reference pulse and the transmitted pulse respectively, yielding a first spectrum E_ref(ω) and a second spectrum E_tran(ω) in complex spectral form, where ω is the angular frequency, and the corresponding frequency axis must be preserved, f = ω / (2π). The phase angles of the first spectrum E_ref(ω) and the second spectrum E_tran(ω) determine the discrete sequence of the original wrapped phase difference with respect to the angular frequency. Discrete sequence Let be a discrete sequence enclosed in the range [-π, π), where the discrete sequence is... It can be represented as:

[0053] (2);

[0054] Here, angle() represents the phase angle function taking a complex number.

[0055] The relationship between angular frequency ω and frequency f is: ω = 2πf. After Fourier transform, the horizontal axis of the spectrum is usually angular frequency ω (unit: radians / second, rad / s), but in practical analysis, frequency f (unit: Hertz, Hz) is more commonly used. The conversion relationship between the two is ω = 2πf, therefore f = ω / (2π).

[0056] Since the arctangent operation causes the phase to be wrapped within the range of [-π, π), the continuous physical phase curve can be recovered by phase unwrapping. The discrete phase difference sequence wrapped within the range of [-π, π) is unwrapped using the adjacent point difference method to obtain the phase difference with respect to the angular frequency.

[0057] According to an embodiment of this application, the adjacent point difference method is used to unwrap the phase of a discrete sequence to obtain the phase difference with respect to angular frequency. This includes: determining the first original wrapped phase difference in the discrete sequence as the first phase difference with respect to angular frequency; determining the i-th phase difference with respect to angular frequency through the following operations: determining the difference between the i-th original wrapped phase difference and the (i-1)-th original wrapped phase difference in the discrete sequence as the initial change; determining a correction change based on the initial change, including: if the initial change is greater than π, subtracting 2π from the initial change to determine the correction change; if the initial change is less than negative π, adding 2π to the initial change to determine the correction change; otherwise, determining the initial change as the correction change; adding the correction change to the (i-1)-th phase difference with respect to angular frequency to obtain the i-th phase difference; where i is an integer greater than 1 and not greater than the length of the discrete sequence.

[0058] Initialize the discrete sequence, remove the original wrapped phase differences corresponding to zero frequencies and angular frequencies with excessively low signal-to-noise ratios, and retain the original wrapped phase differences corresponding to the effective frequency points in the discrete phase difference sequence. Effective frequency points are the angular frequencies that are removed as zero or those with excessively low signal-to-noise ratios.

[0059] The first original wrapper phase difference in the discrete sequence is determined as the i-th phase difference in the phase differences with respect to angular frequency.

[0060] The difference between the phase difference of the i-th original package and the phase difference of the (i-1)-th original package in the discrete sequence is determined as the initial change Δ_0.

[0061] If Δ_0 > π, it is determined to be a positive 2π transition, and the correction change of the (i-1)th phase difference is Δ_corr = Δ_0 - 2π.

[0062] If Δ_0 < -π, it is determined to be a negative 2π transition, and the correction change of the (i-1)th phase difference is Δ_corr = Δ_0 + 2π.

[0063] Otherwise, if -π≤Δ_0≤π, then there is no jump, and the correction change of the (i-1)th phase difference is Δ_corr=Δ_0.

[0064] Adding the correction change to the (i-1)th phase difference with respect to angular frequency yields the ith phase difference, resulting in the curve corresponding to the continuous phase differences with respect to angular frequency after unwrapping.

[0065] According to an embodiment of this application, by detecting the phase jump between the phase differences corresponding to adjacent effective angular frequencies and correcting it in multiples of 2π, the discrete sequence in the range of [-π,π) can be restored to a real physical phase difference curve that changes continuously with the angular frequency, so as to accurately extract the dispersion parameters.

[0066] According to an embodiment of this application, polynomial fitting is performed on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order to extract dispersion parameters, including: determining a fitting model for polynomial fitting of the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order; solving the fitting model using the least squares method to obtain the coefficients of the fitting model; and determining the dispersion parameters based on the coefficients of the fitting model.

[0067] The adjustable order can be 2, 3, 4, or higher. A matrix X can be constructed, where each row of matrix X corresponds to an angular frequency, and the columns of matrix X correspond to the polynomial basis of the fitted model: the first column is the constant term, the second column is... The third column is The fourth column is And so on.

[0068] Using the phase difference curve as the observation vector y, the least squares method is used to solve the fitted model, and the coefficients of the fitted model are obtained:

[0069] (3);

[0070] Where p is the coefficient vector and T represents the inverse matrix. Dispersion parameters are extracted from the coefficient vector.

[0071] According to embodiments of this application, the adjustable order includes 3, the coefficients of the fitting model include first-order coefficients, second-order coefficients, and third-order coefficients, and the dispersion parameters include group delay coefficients, group velocity dispersion coefficients, and third-order dispersion coefficients; determining the dispersion parameters based on the coefficients of the fitting model includes: determining the first-order coefficients as group delay coefficients; determining the second-order coefficients as group velocity dispersion coefficients; and determining the third-order coefficients as third-order dispersion coefficients.

[0072] In one example, the predetermined center angular frequency It can be the frequency corresponding to the spectral peak, and the adjustable order M can be 3, determining the fitting model as a third-order dispersion model. :

[0073] (4);

[0074] Using the least squares method for the third-order dispersion model Solving for the constant coefficients yields the results. First-order coefficients Second-order coefficients and third-order coefficients The coefficients of the fitted model are determined as dispersion parameters: constant phase shift. Group delay coefficient Group velocity dispersion coefficient Third-order dispersion coefficient .

[0075] According to embodiments of this application, polynomial fitting is performed on the continuous phase difference curve after unwrapping to establish a polynomial model of angular frequency offset. The coefficients of the fitted model can be calculated by solving the least squares method, i.e., the dispersion parameters can be estimated, thereby quantifying the phase distortion caused by dispersion effect in terahertz transmission in the medium.

[0076] According to an embodiment of this application, the dispersion parameter includes the group velocity dispersion coefficient; the adjustable compensation intensity factor includes a second-order factor; the filter is constructed such that its frequency domain response has the following term: a second-order frequency offset term; wherein the second-order frequency offset term is the square of the difference between different frequencies in the input spectrum of the filter and a predetermined center angular frequency; the coefficient of the second-order frequency offset term is half of the product of the negative group velocity dispersion coefficient and the second-order factor.

[0077] The filter is applied to the second spectrum, meaning the second spectrum is used as the filter's input spectrum. In one example, the adjustable compensation intensity factor could be a second-order factor. Second-order factor The initial value can be set to 1.0 and adjusted according to whether the predetermined conditions are met.

[0078] The frequency domain response of the filter corresponding to the second-order factor can be expressed as:

[0079] (5);

[0080] Among them, different frequencies in the input spectrum of the filter and the predetermined center angular frequency The square of the difference constitutes the second frequency offset term. Second frequency offset term The negative group velocity dispersion coefficients GVD and second-order factors Half of the product.

[0081] Ignore the constant and linear terms, as they do not change the pulse shape and only cause an overall time shift. Construct a filter. , where j is the imaginary unit.

[0082] According to embodiments of this application, the dispersion parameters include the group velocity dispersion coefficient and the third-order dispersion coefficient; the adjustable compensation intensity factor includes a second-order factor and a third-order factor; the filter is constructed such that its frequency domain response has the following terms: a second-order frequency offset term and a third-order frequency offset term; wherein, the second-order frequency offset term is the square of the difference between different frequencies in the filter's input spectrum and a predetermined center angular frequency; the coefficient of the second-order frequency offset term is half the product of the negative group velocity dispersion coefficient and the second-order factor; wherein, the third-order frequency offset term is the cube of the difference between different frequencies in the filter's input spectrum and the predetermined center angular frequency; the coefficient of the third-order frequency offset term is one-sixth the product of the negative third-order dispersion coefficient and the third-order factor; wherein, the frequency domain response of the filter is the sum of the second-order frequency offset term and the third-order frequency offset term.

[0083] The filter is applied to the second spectrum, meaning the second spectrum is used as the filter's input spectrum. In one example, the adjustable compensation intensity factor could be a second-order factor. and third-order factors Second-order factor and third-order factors The initial value can be set to 1.0 and adjusted according to whether the predetermined conditions are met.

[0084] The frequency domain response of the filter corresponding to the third-order factor can be expressed as:

[0085] (6);

[0086] Among them, different frequencies in the input spectrum of the filter and the predetermined center angular frequency The square of the difference constitutes the second frequency offset term. Second frequency offset term The negative group velocity dispersion coefficients GVD and second-order factors Half of the product; the cube of the difference between different frequencies in the filter's input spectrum and the predetermined center angular frequency constitutes the third frequency offset term. Third frequency offset term The coefficients of the negative third-order dispersion coefficient TOD and the third-order factor One-sixth of the product.

[0087] Then construct a filter .

[0088] According to an embodiment of this application, a frequency domain filter with opposite phase response is constructed based on the extracted dispersion parameters, and an adjustable compensation intensity factor is introduced to flexibly adjust the compensation strength. The filter is applied to the second spectrum, which can cancel the phase distortion introduced by dispersion in the frequency domain, and then recover the compensated transmission pulse in the time domain through inverse transformation.

[0089] Multiplying the frequency domain filter H_comp(ω) by the second spectrum E_tran(ω) yields the third spectrum E_comp(ω):

[0090] E_comp(ω)= E_tran(ω) · H_comp(ω)(7).

[0091] Perform an inverse Fourier transform on the third spectrum E_comp(ω) and take the real part or modulus to obtain the compensated transmission pulse signal_comp(t).

[0092] According to an embodiment of this application, based on the compensated transmission pulse and a reference pulse, at least one of an adjustable order and an adjustable compensation intensity factor is adjusted until a predetermined condition is met to obtain an adaptively compensated transmission pulse, including: determining the pulse broadening coefficient of the compensated transmission pulse relative to the reference pulse; determining the correlation coefficient between the compensated transmission pulse and the reference pulse; wherein the predetermined condition includes the absolute value of the pulse broadening coefficient minus 1 being less than or equal to a first threshold and the correlation coefficient being greater than or equal to a second threshold, or reaching a preset number of iterations.

[0093] The length of the time interval from the first time the signal amplitude of the compensated transmission pulse exceeds the peak value α to the last time it exceeds the peak value α is determined as the pulse width of the compensated transmission pulse, width_comp.

[0094] The pulse broadening factor β of the compensated transmitted pulse signal_comp(t) relative to the reference pulse signal_ref(t):

[0095] β = width_comp / width_ref(8).

[0096] The correlation coefficient r between the compensated transmitted pulse signal_comp(t) and the reference pulse signal_ref(t):

[0097] r=cov(signal_comp(t),signal_ref(t)) / (σ_comp·σ_ref)(9);

[0098] Where cov() represents the calculation of the covariance between the compensated transmission pulse signal_comp(t) and the reference pulse signal_ref(t), σ_comp represents the standard deviation of the compensated transmission pulse signal_comp(t), and σ_ref represents the standard deviation of the reference pulse signal_ref(t).

[0099] If |β-1| is greater than the first threshold ε_β, or if the correlation coefficient r is less than the second threshold r_t, the second-order factor can be adjusted according to the direction of the deviation. Third-order factor An adjustable order M. For example, by increasing the adjustable order M, the fitting similarity can be improved, resulting in more accurate dispersion parameters and more precise phase compensation.

[0100] Based on the adjusted compensation intensity factor and order, the dispersion parameters and filter phase compensation are re-extracted until predetermined conditions are met. That is, the pulse broadening coefficient approaches 1 and the correlation coefficient is maximized, or the preset number of iterations is reached.

[0101] According to an embodiment of this application, based on the pulse broadening coefficient of the compensated transmitted pulse relative to the reference pulse, and the dynamic adjustment of the adjustable order and adjustable compensation intensity factor between the compensated transmitted pulse and the reference pulse, the compensation process is repeated multiple times to make the pulse width of the compensated transmitted pulse approach the reference pulse and maximize the waveform similarity, thereby obtaining an adaptively compensated transmitted pulse and realizing adaptive, high-order dispersion compensation.

[0102] Figure 3 A flowchart of an adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application is shown.

[0103] like Figure 3 As shown, the adaptive compensation method for terahertz transmission dispersion includes operations S1-S13.

[0104] In operation S1, the complete terahertz time-domain signal is acquired and saved.

[0105] In operation S2, the reference pulse and the transmission pulse are extracted from the terahertz time-domain signal.

[0106] In operation S3, a threshold coefficient for calculating the pulse width is set to determine the pulse width of the transmitted pulse before compensation.

[0107] In operation S4, a Fourier transform is performed on the reference pulse and the transmitted pulse.

[0108] In operation S5, the phase angles of the reference pulse and the transmission pulse in the complex frequency domain are extracted to determine the discrete phase difference sequence of the package.

[0109] In operation S6, the discrete phase difference sequence is unwrapped to obtain a continuous phase difference curve.

[0110] In operation S7, polynomial fitting is performed on the continuous phase difference curves to extract the dispersion parameters.

[0111] In operation S8, the compensation intensity factor is determined and the frequency domain filter is constructed.

[0112] In operation S9, the frequency domain filter is applied to the complex spectrum of the transmission pulse to obtain the compensated complex spectrum of the transmission pulse.

[0113] In operation S10, an inverse Fourier transform is performed to obtain the compensated transmission pulse.

[0114] In operation S11, the pulse broadening factor of the compensated transmitted pulse and the cross-correlation coefficient between the compensated transmitted pulse and the reference pulse are calculated.

[0115] In operation S12, it is determined whether the pulse broadening coefficient and cross-correlation coefficient of the compensated transmitted pulse meet the iteration conditions. If the iteration conditions are not met, the process returns to operation S8 to determine a new compensation intensity factor. If the iteration conditions are met, operation S13 is executed.

[0116] In operation S13, the adaptively compensated transmission pulse is output, and the corresponding pulse broadening coefficient, cross-correlation coefficient, and energy retention rate are recorded.

[0117] The adaptive compensation method for terahertz transmission dispersion in this application can be applied to dispersion compensation based on terahertz time-domain spectroscopy. It can effectively solve the problem of pulse broadening and waveform distortion caused by dispersion effect when terahertz pulses are transmitted in a medium or waveguide. By adaptive phase compensation, the original pulse width and waveform are restored, thereby improving the resolution and measurement accuracy of the terahertz detection system.

[0118] This application also provides an adaptive compensation device for terahertz transmission dispersion. The following will combine... Figure 4 The device is described in detail.

[0119] Figure 4 A structural block diagram of an adaptive compensation device for terahertz transmission dispersion according to an embodiment of this application is shown.

[0120] like Figure 4 As shown, the adaptive compensation device 400 for terahertz transmission dispersion in this embodiment includes a first conversion module 410, an acquisition module 420, an extraction module 430, a construction module 440, a compensation module 450, a second conversion module 460, and an adjustment module 470.

[0121] The first conversion module 410 is used to convert the reference pulse and the transmission pulse in the time domain to the frequency domain to obtain the first spectrum and the second spectrum, respectively; wherein, the reference pulse is the terahertz pulse signal returned when the probe contacts the object under test, and the transmission pulse is the terahertz pulse signal returned at the fault point of the object under test.

[0122] The module 420 is used to obtain the phase difference with respect to the angular frequency based on the first spectrum and the second spectrum.

[0123] The extraction module 430 is used to perform polynomial fitting on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order, and extract the dispersion parameters.

[0124] The building module 440 is used to build a filter based on dispersion parameters and an adjustable compensation intensity factor, wherein the phase response of the filter in the frequency domain is set to at least partially compensate for the terms representing dispersion in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation.

[0125] The compensation module 450 is used to apply the filter to the second spectrum to obtain the third spectrum.

[0126] The second conversion module 460 is used to convert the third spectrum to the time domain to obtain the compensated transmission pulse.

[0127] The adjustment module 470 is used to adjust at least one of the adjustable order and the adjustable compensation intensity factor according to the compensated transmission pulse and the reference pulse until a predetermined condition is met to obtain the adaptively compensated transmission pulse.

[0128] According to an embodiment of this application, the obtaining module 420 includes a first determining submodule, a second determining submodule, and a first obtaining submodule.

[0129] The first determining submodule is used to determine a discrete sequence of the original wrapped phase difference with respect to the angular frequency based on the phase angle of the first and second spectra.

[0130] The first submodule is used to perform phase unwrapping on the discrete sequence using the adjacent point difference method to obtain the phase difference with respect to the angular frequency.

[0131] According to an embodiment of this application, the first obtaining submodule includes a first determining unit and a second determining unit.

[0132] The first determining unit is used to determine the first original package phase difference in the discrete sequence as the first phase difference in the phase difference with respect to the angular frequency.

[0133] The second determining unit is used to determine the i-th phase difference among the phase differences with respect to angular frequency through the following operations: determining the difference between the i-th original package phase difference and the (i-1)-th original package phase difference in the discrete sequence as the initial change; determining the correction change based on the initial change, including: if the initial change is greater than π, subtracting 2π from the initial change to determine the correction change; if the initial change is less than negative π, adding 2π to the initial change to determine the correction change; otherwise, determining the initial change as the correction change; adding the correction change to the (i-1)-th phase difference among the phase differences with respect to angular frequency to obtain the i-th phase difference; where i is an integer greater than 1 and not greater than the length of the discrete sequence.

[0134] According to an embodiment of this application, the extraction module 430 includes a second determining submodule, a second obtaining submodule, and a third determining submodule.

[0135] The second determining submodule is used to determine a fitting model that performs a polynomial fitting of the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order.

[0136] The second submodule is used to solve the fitted model using the least squares method to obtain the coefficients of the fitted model.

[0137] The third determination submodule is used to determine the dispersion parameters based on the coefficients of the fitted model.

[0138] According to embodiments of this application, the adjustable order includes 3, the coefficients of the fitting model include first-order coefficients, second-order coefficients and third-order coefficients, and the dispersion parameters include group delay coefficient, group velocity dispersion coefficient and third-order dispersion.

[0139] The third determination submodule includes a third determination unit, a fourth determination unit, and a fifth determination unit.

[0140] The third determining unit is used to determine the first-order coefficients as group delay coefficients.

[0141] The fourth determining unit is used to determine the second-order coefficients as group velocity dispersion coefficients.

[0142] The fifth determining unit is used to determine the third-order coefficients as third-order dispersion coefficients.

[0143] According to an embodiment of this application, the adjustment module 470 includes a first calculation submodule and a second calculation submodule.

[0144] The first calculation submodule is used to determine the pulse broadening factor of the compensated transmitted pulse relative to the reference pulse.

[0145] The second calculation submodule is used to determine the correlation coefficient between the compensated transmission pulse and the reference pulse; wherein the predetermined conditions include the absolute value of the pulse broadening coefficient minus 1 being less than or equal to the first threshold and the correlation coefficient being greater than or equal to the second threshold, or reaching a preset number of iterations.

[0146] According to embodiments of this application, any multiple modules among the first conversion module 410, the obtaining module 420, the extraction module 430, the construction module 440, the compensation module 450, the second conversion module 460, and the adjustment module 470 can be combined into one module, or any one of these modules can be split into multiple modules. Alternatively, at least some of the functions of one or more of these modules can be combined with at least some of the functions of other modules and implemented in one module. According to embodiments of this application, at least one of the first conversion module 410, the obtaining module 420, the extraction module 430, the construction module 440, the compensation module 450, the second conversion module 460, and the adjustment module 470 can be at least partially implemented as hardware circuitry, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system-on-a-chip, a system-on-a-substrate, a system-on-package, an application-specific integrated circuit (ASIC), or implemented in hardware or firmware by any other reasonable means of integrating or packaging the circuitry, or implemented in any one of software, hardware, and firmware methods, or in a suitable combination of any of these. Alternatively, at least one of the first conversion module 410, the obtaining module 420, the extracting module 430, the constructing module 440, the compensation module 450, the second conversion module 460, and the adjustment module 470 may be at least partially implemented as a computer program module, which can perform corresponding functions when the computer program module is run.

[0147] Figure 5 A block diagram of an electronic device suitable for implementing an adaptive compensation method for terahertz transmission dispersion according to an embodiment of this application is shown.

[0148] like Figure 5 As shown, an electronic device 500 according to an embodiment of this application includes a processor 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a storage portion 508 into a random access memory (RAM) 503. The processor 501 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 501 may also include onboard memory for caching purposes. The processor 501 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of this application.

[0149] RAM 503 stores various programs and data required for the operation of electronic device 500. Processor 501, ROM 502, and RAM 503 are interconnected via bus 504. Processor 501 executes various operations of the method flow according to embodiments of this application by executing programs in ROM 502 and / or RAM 503. It should be noted that the programs may also be stored in one or more memories other than ROM 502 and RAM 503. Processor 501 may also execute various operations of the method flow according to embodiments of this application by executing programs stored in said one or more memories.

[0150] According to embodiments of this application, the electronic device 500 may further include an input / output (I / O) interface 505, which is also connected to a bus 504. The electronic device 500 may also include one or more of the following components connected to the input / output (I / O) interface 505: an input section 506 including a keyboard, mouse, etc.; an output section 507 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN card, modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the input / output (I / O) interface 505 as needed. A removable medium 511, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 510 as needed so that computer programs read from it can be installed into the storage section 508 as needed.

[0151] This application also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of this application.

[0152] According to embodiments of this application, the computer-readable storage medium can be a non-volatile computer-readable storage medium, such as including but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to embodiments of this application, the computer-readable storage medium may include ROM 502 and / or RAM 503 and / or one or more memories other than ROM 502 and RAM 503 described above.

[0153] Embodiments of this application also include a computer program product comprising a computer program containing program code for performing the methods shown in the flowchart. When the computer program product is run on a computer system, the program code enables the computer system to implement the adaptive compensation method for terahertz transmission dispersion provided in the embodiments of this application.

[0154] When the computer program is executed by the processor 501, it performs the functions defined in the system / apparatus of this application embodiment. According to the embodiments of this application, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0155] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and may be downloaded and installed via the communication section 509, and / or installed from a removable medium 511. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0156] In such an embodiment, the computer program can be downloaded and installed from a network via communication section 509, and / or installed from removable medium 511. When the computer program is executed by processor 501, it performs the functions defined in the system of this application embodiment. According to embodiments of this application, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0157] According to embodiments of this application, program code for executing the computer programs provided in the embodiments of this application can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0158] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0159] Those skilled in the art will understand that the features described in the various embodiments of this application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments of this application can be combined and / or combined in various ways without departing from the spirit and teachings of this application. All such combinations and / or combinations fall within the scope of this application.

[0160] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.

Claims

1. An adaptive compensation method for terahertz transmission dispersion, characterized in that, The adaptive compensation method includes: The reference pulse and transmission pulse in the time domain are transformed to the frequency domain to obtain the first spectrum and the second spectrum, respectively; wherein, the reference pulse is the terahertz pulse signal returned when the probe contacts the object under test, and the transmission pulse is the terahertz pulse signal returned at the fault point of the object under test. Based on the first spectrum and the second spectrum, the phase difference with respect to the angular frequency is obtained; Based on a predetermined center angular frequency and an adjustable order, a polynomial fit is performed on the phase difference with respect to the angular frequency to extract the dispersion parameters. Based on the dispersion parameters and an adjustable compensation intensity factor, a filter is constructed, wherein the phase response of the filter in the frequency domain is set to at least partially compensate for the terms representing dispersion in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation. Applying the filter to the second spectrum yields the third spectrum; The third spectrum is transformed to the time domain to obtain the compensated transmission pulse; Based on the compensated transmission pulse and the reference pulse, at least one of the adjustable order and the adjustable compensation intensity factor is adjusted until a predetermined condition is met to obtain an adaptively compensated transmission pulse. The step of obtaining the phase difference with respect to the angular frequency based on the first spectrum and the second spectrum includes: Based on the phase angles of the first and second spectra, a discrete sequence of the original wrapped phase difference with respect to the angular frequency is determined; The discrete sequence is phase-unwrapped using the adjacent point difference method to obtain the phase difference with respect to the angular frequency; The step of performing polynomial fitting on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order to extract dispersion parameters includes: Determine a fitting model that performs polynomial fitting on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order; The coefficients of the fitted model are obtained by solving the least squares method. The dispersion parameters are determined based on the coefficients of the fitted model.

2. The adaptive compensation method according to claim 1, characterized in that, The step of using the adjacent-point difference method to unwrap the discrete sequence to obtain the phase difference with respect to the angular frequency includes: The first original wrapper phase difference in the discrete sequence is determined as the first phase difference in the phase differences with respect to angular frequency; The i-th phase difference with respect to angular frequency is determined by the following operation: The difference between the phase difference of the i-th original package and the phase difference of the (i-1)-th original package in the discrete sequence is determined as the initial change amount; Determining the correction change based on the initial change includes: If the initial change is greater than π, the initial change minus 2π is determined as the correction change. If the initial change is less than negative π, the initial change plus 2π is determined as the correction change. Otherwise, the initial change is determined as the correction change. The correction change is added to the (i-1)th phase difference with respect to the angular frequency to obtain the ith phase difference; where i is an integer greater than 1 and not greater than the length of the discrete sequence.

3. The adaptive compensation method according to claim 1, characterized in that, The adjustable order includes 3, the coefficients of the fitting model include first-order coefficients, second-order coefficients and third-order coefficients, and the dispersion parameters include group delay coefficient, group velocity dispersion coefficient and third-order dispersion coefficient. Determining the dispersion parameters based on the coefficients of the fitted model includes: The first-order coefficient is determined as the group delay coefficient; The second-order coefficients are determined as the group velocity dispersion coefficients; The third-order coefficients are determined as the third-order dispersion coefficients.

4. The adaptive compensation method according to claim 1, characterized in that, The dispersion parameters include the group velocity dispersion coefficient; the adjustable compensation intensity factor includes a second-order factor. The filter is constructed such that its frequency domain response has the following term: a second-order frequency offset term; Wherein, the second-order frequency offset term is the square of the difference between different frequencies in the input spectrum of the filter and the predetermined center angular frequency; the coefficient of the second-order frequency offset term is half of the negative product of the group velocity dispersion coefficient and the second-order factor.

5. The adaptive compensation method according to claim 1, characterized in that, The dispersion parameters include the group velocity dispersion coefficient and the third-order dispersion coefficient; the adjustable compensation intensity factor includes a second-order factor and a third-order factor. The filter is constructed such that its frequency domain response has the following terms: a second-order frequency offset term and a third-order frequency offset term; Wherein, the second-order frequency offset term is the square of the difference between different frequencies in the input spectrum of the filter and the predetermined center angular frequency; the coefficient of the second-order frequency offset term is half of the negative product of the group velocity dispersion coefficient and the second-order factor; Wherein, the third frequency offset term is the cube of the difference between different frequencies in the input spectrum of the filter and the predetermined center angular frequency; the coefficient of the third frequency offset term is one-sixth of the negative product of the third-order dispersion coefficient and the third-order factor; The frequency domain response of the filter is the sum of the second-order frequency offset term and the third-order frequency offset term.

6. The adaptive compensation method according to claim 1, characterized in that, The step of adjusting at least one of the adjustable order and the adjustable compensation intensity factor based on the compensated transmission pulse and the reference pulse until a predetermined condition is met to obtain an adaptively compensated transmission pulse includes: Determine the pulse broadening factor of the compensated transmission pulse relative to the reference pulse; Determine the correlation coefficient between the compensated transmitted pulse and the reference pulse; The predetermined conditions include the absolute value of the pulse broadening coefficient minus 1 being less than or equal to a first threshold and the correlation coefficient being greater than or equal to a second threshold, or reaching a preset number of iterations.

7. An adaptive compensation device for terahertz transmission dispersion, characterized in that, The adaptive compensation device includes: The first conversion module is used to transform the reference pulse and the transmission pulse in the time domain to the frequency domain to obtain the first spectrum and the second spectrum, respectively; wherein, the reference pulse is the terahertz pulse signal returned when the probe contacts the object under test, and the transmission pulse is the terahertz pulse signal returned at the fault point of the object under test. The module is used to obtain the phase difference with respect to angular frequency based on the first spectrum and the second spectrum; The extraction module is used to perform polynomial fitting on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order, and extract the dispersion parameters. A construction module is configured to construct a filter based on the dispersion parameters and an adjustable compensation intensity factor, wherein the phase response of the filter in the frequency domain is configured to at least partially compensate for the terms representing dispersion in the fitted polynomial, wherein the adjustable compensation intensity factor indicates the degree of compensation. The compensation module is used to apply the filter to the second spectrum to obtain the third spectrum; The second conversion module is used to transform the third spectrum to the time domain to obtain the compensated transmission pulse; The adjustment module is used to adjust at least one of the adjustable order and the adjustable compensation intensity factor according to the compensated transmission pulse and the reference pulse until a predetermined condition is met to obtain an adaptively compensated transmission pulse. The module obtained includes: The first determining submodule is used to determine a discrete sequence of the original wrapped phase difference with respect to the angular frequency based on the phase angle of the first spectrum and the second spectrum. The first submodule is used to perform phase unwrapping on the discrete sequence using the adjacent point difference method to obtain the phase difference with respect to the angular frequency; The extraction module includes: The second determining submodule is used to determine a fitting model that performs a polynomial fitting on the phase difference with respect to the angular frequency based on a predetermined center angular frequency and an adjustable order. The second submodule is used to solve the fitted model using the least squares method to obtain the coefficients of the fitted model. The third determination submodule is used to determine the dispersion parameters based on the coefficients of the fitted model.

8. An electronic device, comprising: One or more processors; Memory, used to store one or more computer programs. The characteristic feature is that the one or more processors execute the one or more computer programs to implement the steps of the adaptive compensation method according to any one of claims 1 to 6.

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