CN-122017825-A - Hole area enhancement method and system for ground penetrating radar image

CN122017825ACN 122017825 ACN122017825 ACN 122017825ACN-122017825-A

Abstract

A method and a system for enhancing a cavity area of a ground penetrating radar image belong to the technical field of urban road detection. The problem of stable detection and high accuracy edge location in order to solve the realization cavity. The method comprises the steps of collecting an original image in a road by using a ground penetrating radar, performing standardization processing to obtain a standardized image, converting the standardized image into an image frequency domain by using Fourier transformation, defining the frequency variation amplitude of the spectrum energy and the energy gradient representation frequency, constructing a frequency difference ratio, establishing a regularization regulation strategy based on fusion of a first derivative and a second derivative, adjusting the spectrum energy to obtain regularized smooth energy, constructing a frequency gain function, constructing a phase disturbance angle model, calculating an enhanced spectrum by using an adjusted phase angle and combining the frequency gain function, fusing a reconstructed image of the enhanced spectrum with a space-frequency fusion image to obtain a final enhanced image, and constructing local anomaly factors by using the gradient strength of the final enhanced image for boundary calculation and cavity mask generation.

Inventors

KAN QIAN
LIU XING
MENG ANXIN
CHENG GONG
ZHUANG WEIQUN
LI JUNYUAN

Assignees

深城交科技集团股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260416

Claims (9)

1. The cavity area enhancement method of the ground penetrating radar image is characterized by comprising the following steps of: s1, acquiring an original image of the interior of a road by adopting a ground penetrating radar, and then performing standardization processing to obtain a standardized image; S2, converting the standardized image obtained in the step S1 into an image frequency domain by utilizing Fourier transform, defining frequency spectrum energy and energy gradient to represent frequency variation amplitude, and constructing a frequency difference ratio; s3, establishing a regularization regulation strategy based on fusion of the first derivative and the second derivative, and adjusting the spectrum energy to obtain regular smooth energy; S4, constructing a frequency gain function by utilizing the energy gradient obtained in the step S2 and the regular smooth energy obtained in the step S3 in view of the characteristic that the cavity reflection structure always shows local high-frequency response in a frequency domain; S5, constructing a phase disturbance angle model by adopting the frequency difference ratio obtained in the step S2, and then calculating an enhanced frequency spectrum by utilizing the adjusted phase angle and combining a frequency gain function; s6, fusing the reconstructed image of the enhanced spectrum with the space-frequency fusion image to obtain a final enhanced image; S7, constructing local anomaly factors by adopting the gradient strength of the final enhanced image, and performing boundary calculation and cavity mask generation.
2. The method for enhancing the cavity area of the ground penetrating radar image according to claim 1, wherein the method for standardization in the step S1 is to perform gray scale normalization on an original image inside a road to obtain a gray scale image, and then perform zero mean standard deviation unitization processing to obtain a standardized image.
3. The method for enhancing the cavity area of the ground penetrating radar image according to claim 2, wherein the specific implementation method of the step S2 comprises the following steps: S2.1, converting the standardized image obtained in the step S1 into an image frequency domain by utilizing Fourier transform, wherein the expression is as follows: ; Wherein, the Is the image frequency domain; 、 Indexes in the x direction and the y direction of the frequency domain are obtained by frequency coordinates of Fourier transform; In units of imaginary numbers, Is a standardized image; s2.2, defining spectral energy and energy gradient by using an image frequency domain, wherein the expression is as follows: ; ; Wherein, the Is the spectral energy; Is an energy gradient mode; Is a partial differential symbol; S2.3, carrying out normalization processing by combining the energy gradient mode and the spectrum energy, and constructing a frequency difference ratio, wherein the expression is: ; Wherein, the Is the frequency difference ratio.
4. The method for enhancing a cavity area of a ground penetrating radar image according to claim 3, wherein in step S3, the spectrum energy is adjusted to obtain regular smooth energy by constructing a local disturbance regularization factor, and the expression is: ; ; Wherein, the Is a local disturbance regularization factor; adjusting coefficients for the regular factors, which are determined empirically by an expert and are used for adjusting dimensions at the same time; To obtain a first derivative of the spectral energy; To derive a second derivative of the spectral energy; Is a regular weight factor, is empirically determined by an expert and is simultaneously used for adjusting dimension; Is regular smoothed energy.
5. The method for enhancing a cavity area of a ground penetrating radar image according to claim 4, wherein the expression of the frequency gain function constructed in step S4 is: ; Wherein, the Is the frequency gain; is the maximum response scale factor, is determined by expert experience and is used for adjusting dimension; is an exponential control factor, is determined empirically by an expert, and tan h is a hyperbolic tangent function.
6. The method for enhancing a cavity area of a ground penetrating radar image according to claim 5, wherein the specific implementation method of step S5 comprises the steps of: s5.1, constructing a phase disturbance angle model by adopting the differential operation result of the frequency difference ratio obtained in the step S2 along a vertical frequency axis, wherein the expression is as follows: ; Wherein, the Is the phase disturbance angle; Is a phase disturbance factor, is empirically determined by an expert, and is simultaneously used for adjusting dimension; s5.2, calculating the adjusted phase angle, wherein the calculation formula is as follows: ; Wherein, the Is the adjusted phase angle; Is that Is a phase angle of (c); and calculating an enhanced frequency spectrum by combining the frequency gain, wherein the calculation formula is as follows: ; Wherein, the To enhance the spectrum.
7. The method for enhancing a cavity area of a ground penetrating radar image according to claim 6, wherein the specific implementation method of step S6 includes the steps of: s6.1 performing an inverse Fourier transform using the enhanced spectrum to obtain a reconstructed image ; S6.2, introducing a space-frequency double-control model, and fusing space-frequency domain responses to obtain a space-frequency fusion graph, wherein the expression is as follows: ; Wherein, the Is inverse fourier transform; Is a space-frequency fusion graph; Adjusting the index for the standardized image, determined empirically by an expert; Is a gain index, and is determined empirically by an expert; The standard deviation of the local brightness of the standardized image can be calculated by adopting a sliding window mode; s6.3, carrying out weighted fusion on the reconstructed image and the space-frequency fusion image to obtain a final enhanced image 。
8. The method for enhancing the cavity area of the ground penetrating radar image according to claim 7, wherein the specific implementation method of the step S7 comprises the following steps: s7.1, constructing local anomaly factors by adopting gradient intensity of the final enhanced image, wherein the expression is as follows: ; ; Wherein, the Is gradient strength; Is a local abnormality factor; 、 The average value and standard deviation of the gradient intensity are calculated by a local sliding window; s7.2, generating a cavity mask by judging local abnormal factors through a given threshold value, wherein the expression is as follows: ; Wherein, the Is a cavity mask; is an anomaly factor threshold value, and is determined empirically by an expert.
9. A system of hole area enhancement methods of a ground penetrating radar image, characterized by comprising a processor, a memory and a computer program stored in said memory and executable on said processor, said computer program when run implementing the steps of a hole area enhancement method of a ground penetrating radar image according to any of claims 1-8.

Description

Hole area enhancement method and system for ground penetrating radar image Technical Field The invention belongs to the technical field of urban road detection, and particularly relates to a cavity area enhancement method and system of a ground penetrating radar image. Background In the long-term running process of urban road infrastructure, the problem of internal cavities caused by foundation settlement, underground pipeline aging and other factors is increasingly prominent, and the problem gradually evolves into one of key factors threatening road traffic safety. Traditional manual detection methods or borehole sampling techniques suffer from the limitations of low efficiency, high cost, and difficulty in achieving large-scale applications. In order to solve the above-mentioned problems, a noncontact detection means typified by a ground penetrating radar has been attracting attention because of its excellent spatial resolution and high-efficiency data acquisition capability. The technique achieves a non-destructive evaluation of the internal condition of a target structure by transmitting electromagnetic waves and receiving their reflected signals in a medium. However, in practical applications, due to the influence of multiple factors such as material property differences, environmental noise interference, and image processing complexity, two-dimensional or three-dimensional imaging results obtained by the ground penetrating radar often accompany significant artifacts and uncertainties, thereby bringing great difficulty to the positioning and accurate definition of the cavity. The expression forms of such abnormal regions are often characterized by uneven gray distribution, smooth edge transition, abrupt intensity change, etc., and these small changes are still difficult to be effectively extracted and resolved even by means of professional image analysis algorithms. Disclosure of Invention The invention aims to solve the problem of realizing stable detection and high-precision edge positioning of a cavity, and provides a cavity area enhancement method and system of a ground penetrating radar image. In order to achieve the above purpose, the present invention is realized by the following technical scheme: A cavity area enhancement method of a ground penetrating radar image comprises the following steps: s1, acquiring an original image of the interior of a road by adopting a ground penetrating radar, and then performing standardization processing to obtain a standardized image; S2, converting the standardized image obtained in the step S1 into an image frequency domain by utilizing Fourier transform, defining frequency spectrum energy and energy gradient to represent frequency variation amplitude, and constructing a frequency difference ratio; s3, establishing a regularization regulation strategy based on fusion of the first derivative and the second derivative, and adjusting the spectrum energy to obtain regular smooth energy; S4, constructing a frequency gain function by utilizing the energy gradient obtained in the step S2 and the regular smooth energy obtained in the step S3 in view of the characteristic that the cavity reflection structure always shows local high-frequency response in a frequency domain; S5, constructing a phase disturbance angle model by adopting the frequency difference ratio obtained in the step S2, and then calculating an enhanced frequency spectrum by utilizing the adjusted phase angle and combining a frequency gain function; s6, fusing the reconstructed image of the enhanced spectrum with the space-frequency fusion image to obtain a final enhanced image; S7, constructing local anomaly factors by adopting the gradient strength of the final enhanced image, and performing boundary calculation and cavity mask generation. Further, the method of normalization processing in step S1 is to perform gray scale normalization on an original image inside a road to obtain a gray scale map, and then perform zero mean standard deviation unitization processing to obtain a normalized image. Further, the specific implementation method of the step S2 includes the following steps: S2.1, converting the standardized image obtained in the step S1 into an image frequency domain by utilizing Fourier transform, wherein the expression is as follows: Wherein, the Is the image frequency domain;、 Indexes in the x direction and the y direction of the frequency domain are obtained by frequency coordinates of Fourier transform; In units of imaginary numbers, Is a standardized image; s2.2, defining spectral energy and energy gradient by using an image frequency domain, wherein the expression is as follows: Wherein, the Is the spectral energy; Is an energy gradient mode; Is a partial differential symbol; S2.3, carrying out normalization processing by combining the energy gradient mode and the spectrum energy, and constructing a frequency difference ratio, wherein the expression is: Wherein, the Is the freque