CN115598639B - Device and method for collecting face geological conditions by millimeter wave radar in tunnel environment - Google Patents
Device and method for collecting face geological conditions by millimeter wave radar in tunnel environment Download PDFInfo
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- CN115598639B CN115598639B CN202211597715.0A CN202211597715A CN115598639B CN 115598639 B CN115598639 B CN 115598639B CN 202211597715 A CN202211597715 A CN 202211597715A CN 115598639 B CN115598639 B CN 115598639B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
Abstract
The invention discloses equipment and a method for collecting face geological conditions by a millimeter wave radar in a tunnel environment. Firstly, determining the positions of a target object and equipment, then, transmitting millimeter waves by using an array transmitting antenna, receiving reflected echoes by using an array receiving antenna, measuring the position data and the relative distance of the target according to the time difference of receiving and transmitting, and simultaneously, storing related data information. And introducing a holographic imaging algorithm into short-range millimeter wave imaging, outputting a gray-scale image according to an imaging result, and outputting fault information according to an edge feature extraction algorithm of the gray-scale image. The invention overcomes the difficulties that the light condition is poor and the imaging condition is influenced by dust in the traditional tunnel environment, and effectively improves the resolution and the imaging quality.
Description
Technical Field
The invention belongs to the field of geological fault information, and particularly relates to equipment and a method for collecting tunnel face geological conditions by using a millimeter wave radar in a tunnel environment.
Background
Geological fault information of an excavation section is required to be described at any time in the drilling and blasting tunnel construction process, and the geological stability state of the tunnel construction position is further mastered, so that the rationality of tunnel construction is guided. At present, the most common structural plane information acquisition methods are rock mass data acquired by a geological compass through an artificial measurement method and post-processing through photographic imaging. The manual observation is inconvenient, the observation is not objective enough due to different investigation experiences of everyone and different results obtained by final statistics, the fault characteristics can not be comprehensively reflected by the method with long time and statistical recording, and the tunnel construction can not be reasonably and effectively guided due to the fact that dust in the tunnel is large, light conditions are poor and photographic imaging results are poor.
Disclosure of Invention
In order to overcome the problems that the observation is inconvenient and the photographic imaging result is poor when the existing manual method is adopted, the invention provides equipment and a method for collecting the geological condition of the tunnel face by using a millimeter wave radar in a tunnel environment, so that the accuracy and the portability of acquiring the fault condition in the tunnel are improved.
In order to achieve the purpose, the invention provides the following scheme: the method for collecting the face geological condition by the millimeter wave radar in the tunnel environment comprises the following steps:
selecting the position of equipment and fixing the equipment;
transmitting millimeter waves through an array transmitting antenna, and receiving reflected waves through an array receiving antenna; storing the reflected wave data through a data storage device;
acquiring a holographic image of the palm surface based on the reflected wave data;
and obtaining a gray-scale image according to the holographic image, performing edge feature extraction on the gray-scale image, outputting an edge feature map, and obtaining fault information according to the edge feature map.
Preferably, the method for selecting and fixing the equipment comprises the following steps:
and (3) building a platform for placing equipment to keep the equipment horizontal, wherein the equipment is positioned in the center of the tunnel face.
Preferably, the method of collecting data comprises:
the millimeter waves are transmitted through the array transmitting antenna, the array receiving antenna receives the reflected waves of each frequency point in the bandwidth to obtain reflected wave data, the data storage device stores the reflected wave data, and the position data and the relative distance of the target are measured according to the time difference of receiving and transmitting.
Preferably, the method of holographic imaging comprises:
transforming the stored data into a spatial frequency domain through Fourier, namely representing the echo into superposition of plane waves with different azimuth angles, pitch angles and wave numbers, performing approximate processing on the superposed plane wave components through two-dimensional inverse Fourier transform, and improving the resolution of imaging through phase compensation; and performing Fourier inverse transformation on the data subjected to the phase compensation to obtain a holographic image of the palm surface.
Preferably, the method of edge feature extraction includes:
obtaining a gray-scale image according to the holographic image, performing smooth filtering processing on the gray-scale image by using a Gaussian function, and removing noise points and false edge points while smoothing the image;
performing finite difference calculation of first-order partial differential on the smoothed image, calculating the gradient amplitude and the gradient direction of the image, comparing the gradient amplitude of a certain pixel point with the gradient amplitudes of two adjacent pixel points in the gradient direction based on the gradient amplitude image, and if the gradient amplitude is the maximum value, the pixel point is an edge feature point, otherwise, the pixel point is assigned to be 0;
and detecting and connecting edges by adopting a double-threshold algorithm, obtaining two thresholds for the image subjected to non-maximum value inhibition by adopting an accumulative histogram method to distinguish characteristic edge points, and then outputting an edge characteristic diagram of the tunnel face to obtain a fault detail image so as to obtain fault information.
The invention also provides equipment for collecting the geological conditions of the tunnel face by the millimeter wave radar in the tunnel environment, which is characterized in that,
control means for transmitting millimeter waves and receiving reflected waves;
the data storage module is connected with the control device and used for storing the reflected wave data acquired by the control device;
and the data processing module is connected with the data storage module and is used for processing the reflected wave data to generate a fault detail image.
Preferably, the control device includes: the array antenna comprises an array transmitting antenna, an array receiving antenna and a shielding belt;
the array transmitting antenna and the array receiving antenna are positioned right in front of the center of the tunnel face;
the shielding belt is used for shielding the array receiving antenna to directly receive the millimeter waves transmitted by the array transmitting antenna.
Preferably, the data processing module comprises: the holographic imaging unit and the edge feature extraction unit;
the holographic imaging unit is used for obtaining a holographic image of a tunnel face based on the reflected wave data;
the edge feature extraction unit is used for obtaining a gray-scale image according to the holographic image, extracting edge features of the gray-scale image and outputting an edge feature image.
The invention discloses the following technical effects:
the method for collecting the geological condition of the tunnel face by the millimeter wave radar in the tunnel environment determines the positions of the target object and the equipment. By emitting millimeter waves with certain bandwidth, after reflection, the array receiving antenna receives reflection echoes from the tunnel face and stores data, so that the data analysis in the later period is facilitated. And processing the collected echo data, introducing a Fourier transform-based holographic imaging algorithm into short-range millimeter wave imaging by using optical holographic imaging as a reference, and obtaining a millimeter wave image of the tunnel face. And outputting a gray-scale image according to the imaging result, extracting edge features of the gray-scale image, and finally outputting an edge feature map of the tunnel face to acquire fault information. By the method, more comprehensive tunnel face information can be collected, the influence of poor light and low visibility in the tunnel can be avoided, fault information can be accurately obtained, and therefore the construction process can be guided more reasonably and effectively. And the holographic imaging algorithm is introduced into the short-range millimeter wave imaging, so that the resolution of the tunnel face structural plane image is improved.
The invention provides a device for collecting tunnel face geological conditions by a millimeter wave radar in a tunnel environment, which comprises a control device, a receiving device and a transmitting device, wherein the control device is used for controlling a transmitting antenna to transmit millimeter waves with certain bandwidth; the data storage device is used for storing the image information carried in the reflected echo; the processing device is used for extracting and processing the stored image data through a holographic imaging algorithm and an edge extraction characteristic algorithm to obtain a structural section of the tunnel face; comparatively comprehensive tunnel face information can be collected to can avoid receiving the interior light of tunnel poor, the influence that visibility is low, comparatively accurate acquisition fault information, thereby more reasonable effectual guidance work progress.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a flow chart of a method of collecting geology in accordance with an embodiment of the present invention;
FIG. 2 is an algorithm flow diagram (a) and an algorithm flow diagram (b) of an embodiment of the present invention;
FIG. 3 is a schematic view of the position of an apparatus according to an embodiment of the present invention;
fig. 4 is a block diagram of an apparatus for collecting geology according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description thereof.
Fig. 1 shows a flow chart of a method for collecting geology using millimeter wave radar in a tunnel environment according to an embodiment of the present invention.
As shown in fig. 1, the location of the target object and the device is determined. In the embodiment, the installation position of the equipment is determined, the data information carried by the echo is increased, and the accuracy of the tunnel face structure information is improved.
Further optimizing the scheme, the target object is a tunnel face, the installation position of the equipment is determined, a simple tripod and a placement device are manufactured in a tunnel which uses drilling and blasting as a main construction mode, the equipment needs to be kept horizontal and is positioned in the center of the tunnel face at a certain distance. Since the beam angle of the short-range millimeter wave is 80 degrees (40 degrees parallel to the horizontal plane), the arrangement needs to be positioned at the center of the tunnel face at a certain distance. Supposing that the working frequency of millimeter waves is 70GHz, the corresponding wavelength λ =3mm, the diameter of the tunnel is 10 meters, and the device needs to be about 6 meters away from the tunnel face, so as to ensure that the range of radio waves (millimeter waves) radiated by the transmitting antenna is wider, and the receiving antenna receives reflected echoes carrying more information.
A schematic of the location of the device is shown in figure 3.
After the target object and the equipment installation position are determined, millimeter waves with a certain bandwidth are emitted, and after the millimeter waves are reflected by the tunnel face, the array receiving antenna receives reflection echoes from the tunnel face to acquire data of the tunnel face. In an embodiment, the control device can remotely control the transmitting antenna to emit millimeter waves (radio waves) with a certain bandwidth, and acquire a large amount of reflected echo data through the receiving antenna.
Specifically, millimeter waves with a certain bandwidth can be controlled by the control device to be radiated from the transmitting antenna, the array receiving antenna receives a reflected echo of each frequency point in the bandwidth to obtain data, and after a signal sent by the radiation source is reflected by a target at a position (X, Y), the signal received by the receiving antenna at the position (X, Y) is:
wherein A (x, y) is the reflection coefficient of the target, K is the wave number, K x 、K y 、K z Are the components of the beam K that are,
fig. 2 (a) shows a flow chart of the holographic algorithm, and as shown in fig. 2 (a), after the echo signal is collected, a Fourier transform-based holographic imaging algorithm is introduced into short-range millimeter wave imaging for the collected echo signal, so as to obtain a millimeter wave image of the tunnel face. In the embodiment, the acquired echo signals are subjected to spatial frequency spectrum transformation through a processing device, the signals are converted into a spatial domain from a frequency domain in the processing device, then data are subjected to approximation processing and phase compensation, and finally, inverse Fourier transform is performed on the data, so that an imaging result is obtained.
The method comprises the following specific steps:
(1) The exponential part of the echo signal function, which represents the spherical electromagnetic wave scattered by a point source on the target, is analyzed as:
(2) The stored data is transformed into the spatial frequency domain by Fourier, namely, echoes are represented as superposition of plane waves with different azimuth angles and elevation angles and different wave numbers in a certain range.
To pair
The transformation is carried out to obtain:
the superposition of plane waves can be expressed as:
(3) And then the superposed plane wave components are subjected to approximate processing through two-dimensional inverse Fourier transform.
Fourier transform is carried out on the target reflection coefficient A (x, y):
performing an inverse fourier transform to:
(4) Phase positionCompensation factor
And the spherical wave is changed into a plane wave which represents exponentially attenuated high-frequency components, and the resolution of imaging is improved through phase compensation.
(5) And performing Fourier inverse transformation on the data subjected to the phase compensation to obtain a two-dimensional holographic image of the palm surface.
The imaging formula of the millimeter wave two-dimensional holographic imaging is as follows:
fig. 2 (b) shows a flow chart of the edge feature extraction algorithm, and as shown in fig. 2 (b), after the two-dimensional hologram of the palm surface is obtained, the imaging result is processed to output a gray-scale image, the gray-scale image is subjected to edge feature extraction, and finally, the edge feature image of the palm surface is output to obtain the fault information. In the embodiment, the output gray-scale image is processed by an edge extraction module in the processing device, and the palm section fault information is accurately acquired by extracting edge feature points in the gray-scale image.
The method comprises the following specific steps:
(1) And performing smooth filtering processing on the gray-scale image by using a Gaussian function, and removing noise points and false edge points while smoothing the image. That is, a two-dimensional gaussian function G (x, y) is used to perform convolution operation with the original image f (x, y), so as to obtain a smoothed image I (x, y):
I(x,y)=f(x,y)*G(x,y)。
(2) And performing finite difference calculation of first-order partial differential on the smoothed image, and calculating the gradient amplitude and the gradient direction of the smoothed image. Of which 2 x 2 is the first order differential convolution template G x And G y As follows:
the partial differential of the smoothed image I (x, y) in the x-direction and the y-direction can be expressed as:
G x =（I(x,y+1)-I(x,y)+[x+1,y+1]+I(x+1,y)）/2；
G y =（I(x,y)-I(x+1,y)+[x,y+1]+I(x+1,y+1)）/2。
the gradient magnitude and gradient direction can be calculated using the direct coordinate formula as follows:
(3) Traversing the gradient amplitude image, comparing the gradient amplitude of a certain pixel point with the gradient amplitudes of two adjacent pixel points in the gradient direction, if the value is maximum, the pixel point is an edge feature point, otherwise, assigning the value to be 0.
(4) Edges are detected and connected using a dual threshold algorithm. And obtaining two thresholds by adopting an accumulative histogram method for the image subjected to non-maximum value inhibition to distinguish characteristic edge points, and then outputting the edge characteristic image of the tunnel face to obtain a fault detail image so as to obtain fault information.
Fig. 4 shows a block diagram of an apparatus for collecting geology using millimeter-wave radar in a tunnel environment, according to an embodiment of the present invention.
As shown in fig. 4, the apparatus comprises control means, data storage means and processing means. The control device comprises a transmitting array antenna, a receiving array antenna and an isolation strip. The processing device comprises a holographic imaging unit and an edge extraction unit.
The control device controls the transmitting antenna to transmit millimeter waves with certain bandwidth, and controls the receiving antenna to receive reflected echo to obtain a tunnel face echo signal.
And the data storage device is used for storing the image information carried in the reflected echo.
And the processing device extracts and stores the image data, processes the image data through a holographic imaging algorithm and an edge extraction characteristic algorithm and obtains the structural section of the tunnel face.
The device for collecting geological conditions by using the millimeter wave radar applied to the tunnel environment comprises a control device, a receiving device and a transmitting antenna, wherein the control device controls the transmitting antenna to transmit millimeter waves with certain bandwidth; the data storage device stores the image information carried in the reflected echo; the processing device extracts and processes the stored image data through a holographic imaging algorithm and an edge extraction characteristic algorithm to obtain a structural section of a tunnel face; comparatively comprehensive tunnel face information can be collected to can avoid receiving the interior light of tunnel poor, the influence that visibility is low, comparatively accurate acquisition fault information, thereby more reasonable effectual guidance work progress.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (8)
1. The method for collecting the tunnel face geological condition by the millimeter wave radar under the tunnel environment is characterized by comprising the following steps:
selecting the position of geological collection equipment, and fixing the equipment;
transmitting millimeter waves through an array transmitting antenna, and receiving reflected waves through an array receiving antenna; storing the reflected wave data by a data storage device;
acquiring a holographic image of the palm surface based on the reflected wave data;
and obtaining a gray-scale image according to the holographic image, extracting edge features of the gray-scale image, outputting an edge feature map, and obtaining geological information according to the edge feature map.
2. The method for collecting the geological conditions of the tunnel face by the millimeter-wave radar in the tunnel environment according to claim 1, wherein the method for selecting and fixing the equipment comprises the following steps:
and (3) building a platform for placing the geological collection equipment to keep the geological collection equipment horizontal, wherein the geological collection equipment is positioned in the center of the tunnel face.
3. The method for collecting the geological conditions of the tunnel face by the millimeter-wave radar in the tunnel environment according to claim 1, wherein the method for collecting the data comprises the following steps:
the millimeter waves are transmitted through the array transmitting antenna, the array receiving antenna receives reflected waves of each frequency point in the bandwidth to obtain reflected wave data, the data storage device stores the reflected wave data, and position data and relative distance of a target are measured according to the time difference of receiving and transmitting.
4. The method for collecting geology of a tunnel face by using a millimeter wave radar in a tunnel environment according to claim 1, wherein the holographic imaging method comprises the following steps:
the stored data is converted into a spatial frequency domain through Fourier, namely, the echo is represented as superposition of plane waves with different azimuth angles, pitch angles and wave numbers, the superposed plane wave components are subjected to approximate processing through two-dimensional inverse Fourier transform, and then the imaging resolution is improved through phase compensation; and performing Fourier inverse transformation on the data subjected to the phase compensation to obtain a holographic image of the palm surface.
5. The method for collecting the geological conditions of the tunnel face by the millimeter-wave radar in the tunnel environment according to claim 1, wherein the method for extracting the edge features comprises the following steps:
obtaining a gray-scale image according to the holographic image, performing smooth filtering processing on the gray-scale image by using a Gaussian function, and removing noise points and false edge points;
performing finite difference calculation of first-order partial differential on the smoothed image, calculating the gradient amplitude and the gradient direction of the smoothed image, comparing the gradient amplitude of a certain pixel point with the gradient amplitudes of two adjacent pixel points in the gradient direction on the basis of the gradient amplitude image, wherein the maximum value is an edge feature point, and otherwise, the value is assigned to be 0;
and detecting and connecting edges by adopting a double-threshold algorithm, obtaining two thresholds for the image subjected to non-maximum value inhibition by adopting an accumulative histogram method, distinguishing characteristic edge points through the thresholds, and outputting an edge characteristic diagram of the tunnel face to obtain geological information.
6. The equipment for collecting the face geological condition by the millimeter wave radar under the tunnel environment is characterized in that,
control means for transmitting millimeter waves and receiving reflected waves;
the data storage module is connected with the control device and used for storing the reflected wave data acquired by the control device;
and the data processing module is connected with the data storage module and used for processing the reflected wave data to generate an edge characteristic diagram.
7. The apparatus for collecting geology of a tunnel face by using millimeter wave radar in a tunnel environment according to claim 6,
the control device includes: the array antenna comprises an array transmitting antenna, an array receiving antenna and a shielding belt;
the array transmitting antenna and the array receiving antenna are positioned right in front of the center position of the tunnel face;
the shielding belt is used for shielding the array receiving antenna to directly receive the millimeter waves transmitted by the array transmitting antenna.
8. The apparatus for millimeter wave radar collection of geology of a tunnel face under a tunnel environment according to claim 6,
the data processing module comprises: the holographic imaging unit and the edge feature extraction unit;
the holographic imaging unit is used for obtaining a holographic image of the palm surface based on the reflected wave data;
the edge feature extraction unit is used for obtaining a gray-scale image based on the holographic image, extracting edge features of the gray-scale image and outputting an edge feature image.
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