Ground penetrating radar adaptive gain method

Abstract

The invention discloses a ground penetrating radar adaptive gain method comprising the following steps: S1, selecting a to-be-gained radar data profile, and obtaining the overall attenuation trend; s2, acquiring an analysis signal; s3, calculating the envelope of each column of signals and the average value of each row of the envelope matrix; s4, fitting an average value of each row of the envelope matrix according to a least square method and a model function to obtain an attenuation coefficient; and S5, obtaining a gain coefficient through the attenuation coefficient, and gaining each column in the radar data profile in the step S1 based on the gain coefficient. The method has the beneficial effects that the gain process and the calculation method have a good gain effect on original data acquired by ground penetrating radars with different frequencies under different working conditions, and parameter setting is not needed, so that the signal-to-noise ratio and the image definition of radar signals in the whole effective depth range are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radar gain, in particular to a ground penetrating radar adaptive gain method. Background Art

[0002] In existing GPR systems, most raw data collected requires some post-processing gain to visualize the radar pulse signal. This is because as electromagnetic waves propagate deeper underground, the signal attenuates significantly, making it difficult to identify targets. Traditional fixed gain methods can easily lead to oversaturation of shallow-layer signals, while deeper signals remain blurred. Furthermore, some gain methods require parameter adjustment for optimal results, making them difficult for field personnel to analyze and process data. Furthermore, there is no standardized gain method for subsequent automatic identification of radar defects, resulting in significant variability in the final data.

[0003] Commonly used GPR gain methods include linear gain, where the gain increases over time; exponential gain, where the gain increases exponentially; and segmented gain, which divides the time axis into multiple segments and sets independent gain values ​​for each segment. These methods are not adaptive, and applying a single method to all data gain processing results can lead to inconsistent gain effects due to data variations. Furthermore, exponential and segmented gain require parameter adjustments tailored to the data, making it difficult to quickly achieve optimal gain results. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a ground penetrating radar adaptive gain method.

[0005] The object of the present invention is achieved by the following technical solution: A ground penetrating radar adaptive gain method comprises the following steps:

[0006] S1: Select the radar data profile to be amplified and obtain the overall attenuation trend;

[0007] S2: Get the analytical signal;

[0008] S3: Calculate the envelope of each column signal and the average value of each row of the envelope matrix;

[0009] S4: The attenuation coefficient is obtained by fitting the average value of each row of the envelope matrix using the least squares method and the model function;

[0010] S5: Obtain a gain coefficient through the attenuation coefficient, and gain each column in the radar data profile in step S1 based on the gain coefficient.

[0011] Preferably, step S1 further includes the following steps:

[0012] S11: Assume that the radar data profile to be amplified is an M×N matrix A, where M is the number of sampling points of the radar data and N is the number of measurement points of the radar data;

[0013] S12: Calculate the absolute value of matrix A and matrix B to flip the radar signal to obtain the overall attenuation trend of the signal.

[0014] B=|A|.

[0015] Preferably, the method further comprises the following steps:

[0016] S21: Let each column of matrix B be B i ,i∈[0,N-1], for B i Perform Fourier transform to convert the signal from time domain to frequency domain.

[0017] X[k]=DFT{B i};

[0018] Where X[k] is the result of discrete Fourier transform, and DFT is discrete Fourier transform;

[0019] S22: Construct frequency domain multiplier H[k] according to different value ranges of k,

[0020]

[0021] S23: Filtering in the frequency domain,

[0022] Z[k]=X[k]·H[k];

[0023] The inverse transform yields the complex signal,

[0024] z[n]=IDFT{Z[k]};

[0025] Among them, IDFT is the inverse discrete Fourier transform;

[0026] S24: Hilbert transform to imaginary part,

[0027]

[0028] Among them, Im is the imaginary part;

[0029] S25: The original signal and the corresponding Hilbert transform form an analytical signal.

[0030]

[0031] Preferably, step S3 further includes the following steps:

[0032] S31: Calculate each column signal B i The envelope,

[0033]

[0034] The size of the envelope matrix E is M×N, then E i =B i ;

[0035] S32: Calculate the average value of each row of the envelope matrix E A vector of size M×1,

[0036]

[0037] Preferably, in step S4, the fitted model function is:

[0038] f(x)=α·e -bx +c;

[0039] Fitting with the least squares method and the model function Get a, b, c,

[0040] Preferably, in step S5, the reciprocal of the attenuation coefficient is the gain coefficient g,

[0041]

[0042] Each column of the original matrix A is multiplied by the gain coefficient to obtain the data after gain.

[0043] A g =A·g.

[0044] The present invention has the following advantages: the gain process and calculation method of the present invention have a good gain effect on the original data collected by ground penetrating radars of different frequencies under different working conditions, and no parameter setting is required, thereby improving the signal-to-noise ratio and image clarity of the radar signal within the entire effective depth range. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a structural diagram of the process flow of the ground penetrating radar adaptive gain method. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0048] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0049] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0050] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is typically placed when in use, or are the orientations or positional relationships commonly understood by those skilled in the art. These terms are intended only to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0051] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0052] In this embodiment, if Figure 1 As shown, a ground penetrating radar adaptive gain method is characterized by comprising the following steps:

[0053] S1: Select the radar data profile to be amplified and obtain the overall attenuation trend; specifically, the following steps are included:

[0054] S11: Assume that the radar data profile to be amplified is an M×N matrix A, where M is the number of sampling points of the radar data and N is the number of measurement points of the radar data;

[0055] S12: Calculate the absolute value of matrix A and matrix B to flip the radar signal to obtain the overall attenuation trend of the signal.

[0056] B=|A|.

[0057] S2: Acquire the analytical signal; specifically, it also includes the following steps:

[0058] S21: Let each column of matrix B be B i ,i∈[0,N-1], for B i Perform Fourier transform to convert the signal from time domain to frequency domain.

[0059] X[k]=DFT{B i};

[0060] Where X[k] is the result of discrete Fourier transform, and DFT is discrete Fourier transform;

[0061] S22: Construct frequency domain multiplier H[k] according to different value ranges of k,

[0062]

[0063] S23: Filtering in the frequency domain,

[0064] Z[k]=X[k]·H[k];

[0065] The inverse transform yields the complex signal,

[0066] z[n]=IDFT{Z[k]};

[0067] Among them, IDFT is the inverse discrete Fourier transform;

[0068] S24: Hilbert transform to imaginary part,

[0069]

[0070] Among them, Im is the imaginary part;

[0071] S25: The original signal and the corresponding Hilbert transform form an analytical signal.

[0072]

[0073] S3: Calculate the envelope of each column signal and the average value of each row of the envelope matrix; specifically, it also includes the following steps:

[0074] S31: Calculate each column signal B i The envelope,

[0075]

[0076] The size of the envelope matrix E is M×N, then E i =B i ;

[0077] S32: Calculate the average value of each row of the envelope matrix E A vector of size M×1,

[0078]

[0079] S4: The attenuation coefficient is obtained by fitting the average value of each row of the envelope matrix using the least squares method and the model function; specifically, the fitted model function is:

[0080] f(x)=a·e -bx +c;

[0081] Fitting with the least squares method and the model function Get a, b, c, Used to calculate the gain coefficient for unearned points.

[0082] S5: Obtain a gain coefficient through the attenuation coefficient, and perform a gain on each column in the radar data profile in step S1 based on the gain coefficient. Specifically, the reciprocal of the attenuation coefficient is the gain coefficient g.

[0083]

[0084] Each column of the original matrix A is multiplied by the gain coefficient to obtain the data after gain.

[0085] A g =A·g.

[0086] The gain process and calculation method of the present invention have a good gain effect on the original data collected by ground penetrating radars of different frequencies under different working conditions, and no parameter setting is required, thereby improving the signal-to-noise ratio and image clarity of the radar signal within the entire effective depth range.

[0087] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A ground penetrating radar adaptive gain method, characterized by: The following steps are involved: S1: Select the radar data profile to be amplified and obtain the overall attenuation trend; S2: Get the analytical signal; S3: Calculate the envelope of each column signal and the average value of each row of the envelope matrix; S4: The attenuation coefficient is obtained by fitting the average value of each row of the envelope matrix using the least squares method and the model function; S5: Obtain a gain coefficient through the attenuation coefficient, and gain each column in the radar data profile in step S1 based on the gain coefficient.

2. The ground penetrating radar adaptive gain method according to claim 1, characterized in that: The step S1 further includes the following steps: S11: Assume that the radar data profile to be amplified is an M×N matrix A, where M is the number of sampling points of the radar data and N is the number of measurement points of the radar data; S12: Calculate the absolute value of matrix A and matrix B to flip the radar signal to obtain the overall attenuation trend of the signal. B=|A|.

3. The ground penetrating radar adaptive gain method according to claim 2, characterized in that: The step S2 further includes the following steps: S21: Let each column of matrix B be B i ,i∈[0,N-1], for B i Perform Fourier transform to convert the signal from time domain to frequency domain. X[k]=DFT{B i }; Where X[k] is the result of discrete Fourier transform, and DFT is discrete Fourier transform; S22: Construct frequency domain multiplier H[k] according to different value ranges of k, S23: Filtering in the frequency domain, Z[k]=X[k]·H[k]; The inverse transform yields the complex signal, z[n]=IDFT{Z[k]}; Among them, IDFT is the inverse discrete Fourier transform; S24: Hilbert transform to imaginary part, Among them, Im is the imaginary part; S25: The original signal and the corresponding Hilbert transform form an analytical signal.

4. The ground penetrating radar adaptive gain method according to claim 3, characterized in that: The step S3 further includes the following steps: S31: Calculate each column signal B i The envelope, The size of the envelope matrix E is M×N, then E i =B i ; S32: Calculate the average value of each row of the envelope matrix E A vector of size M×1, 5. The ground penetrating radar adaptive gain method according to claim 4, characterized in that: In step S4, the fitted model function is: f(x)=a·x -bx +c; Fitting with the least squares method and the model function Get a, b, c, 6. The ground penetrating radar adaptive gain method according to claim 5, characterized in that: In step S5, the reciprocal of the attenuation coefficient is the gain coefficient g. Each column of the original matrix A is multiplied by the gain coefficient to obtain the data after gain. A g =A·g。

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