CN105092705B - The multi-modal signal detecting method and device of a kind of steel rail defect - Google Patents

Abstract

The present invention provides a multi-modal signal detection method and device for rail defects. The method includes: acquiring optical signals of the surface area to be tested of the rail to be tested, and determining the spatial distribution information of the surface damage of the rail according to the optical signals and Surface damage type; obtain the photoacoustic signal of the location area where the rail surface damage is located, and determine the spatial distribution information and shallow damage type of the rail shallow damage according to the photoacoustic signal; obtain the location area of the rail shallow damage And the ultrasonic echo signals in deeper areas, and according to the ultrasonic echo signals, determine the spatial distribution information and deep damage types of rail deep damage; according to the spatial distribution information of rail surface, shallow and deep damage, the optical , photoacoustic and ultrasonic testing data, and perform three-dimensional reconstruction of the rail to be tested. The invention effectively improves the accuracy and efficiency of the detection results, and can display the defects of the rail more intuitively and vividly.

Description

A multi-mode signal detection method and device for rail defects

technical field

The invention relates to the technical field of non-destructive testing, in particular to a multi-mode signal detection method and device for rail defects.

Background technique

Ultrasonic technology has been widely and maturely applied in the field of non-destructive testing, and photoacoustic imaging technology, as a non-destructive testing technology developed in recent years, has also been fully developed. In the defect detection of high-speed rail rails, ultrasonic technology makes full use of the high penetration of ultrasonic signals, as well as the difference in acoustic impedance between rails and damaged gaps, corrosion, etc., and uses probes to emit ultrasonic beams and obtain echo signals. The signal is analyzed and processed to judge and identify the defect information of the rail. Photoacoustic imaging technology combines the high contrast characteristics of pure optical imaging and the high penetration characteristics of pure ultrasonic imaging. The attenuation and scattering of ultrasound by rails is much smaller than the attenuation and scattering of light by rails. Ultrasonic waves are detected by broadband ultrasonic detectors instead of optical imaging. The detection of scattered photons in the medium can provide high-contrast and high-resolution images, and its imaging can reach centimeter-level depth and micron-level resolution. Using short-pulse laser as the excitation source and photoacoustic signal as the information carrier, the imaging is carried out according to the principle that the optical absorption coefficient of the rail and the damaged gap, corrosion, etc. have a large difference to the specific wavelength laser, and then radiate different intensities of ultrasonic waves. The photoacoustic signal is used for image reconstruction to obtain rail defect information.

Most non-destructive testing techniques require a comprehensive scan of the rail to obtain the defect information of the rail, and the detection efficiency is very low. In addition, ultrasound is insufficient for the detection of rail surface and shallow defects, and photoacoustics is insufficient for the detection of internal defects of rails, and the detection range is limited. However, for detection objects such as steel rails, most of the defects originate from the surface, and the position of the surface defects can only be determined, and the detection cannot be carried out to the inside. Therefore, the detection range is limited and the detection efficiency is low.

Contents of the invention

In view of the above problems, the present invention provides a multi-modal signal detection method and device for rail defects to solve the problems of limited detection range and low detection efficiency in the existing non-destructive testing technology for rail surface defect detection technology.

According to one aspect of the present invention, a multimodal signal detection method for rail defects is provided, the method comprising:

Obtaining the optical signal of the area to be tested on the surface of the rail to be tested, and determining the spatial distribution information and the type of surface damage of the rail surface according to the optical signal;

Obtaining a photoacoustic signal in the area where the surface damage of the rail is located, and determining the spatial distribution information of the shallow damage of the rail and the type of the shallow damage according to the photoacoustic signal;

Obtaining the ultrasonic echo signals of the position area where the shallow layer damage of the rail is located and the deeper area, and determining the spatial distribution information and the type of deep damage of the rail according to the ultrasonic echo signal;

According to the spatial distribution information and surface damage type of rail surface damage, the spatial distribution information and shallow damage type of rail shallow damage, and the spatial distribution information and deep damage type of rail deep damage, the rail to be tested is Perform 3D reconstruction.

Optionally, the acquisition of the photoacoustic signal of the area where the surface damage of the rail is located, and according to the photoacoustic signal, determining the spatial distribution information and the type of shallow damage of the rail, specifically include:

Obtaining a photoacoustic signal generated in the area where the rail surface damage is located, performing image reconstruction according to the photoacoustic signal, and obtaining a photoacoustic image;

The photoacoustic image is processed and analyzed to determine the spatial distribution information of the shallow damage of the rail and the type of the shallow damage.

Optionally, the spatial distribution information of the rail surface damage includes: location, size, and extension direction of the rail surface damage.

According to another aspect of the present invention, a multi-modal signal detection device for rail defects is provided, the device comprising:

A light source, a CCD camera, an optical fiber, a focusing mirror, a multi-element array ultrasonic probe, a pulse laser, a beam expander, a multi-channel parallel acquisition circuit and a computer; The control end of the parallel acquisition circuit is connected, and the multi-channel parallel acquisition circuit is connected with the computer;

The light source is used to irradiate the rail to be tested;

The CCD camera is used to collect optical signals of the area to be tested on the surface of the rail to be tested, and transmit the collected optical signals to the multi-channel parallel acquisition circuit;

The pulsed laser is used to generate a pulsed laser that scans the area to be measured on the surface of the rail. After the pulsed laser is sequentially expanded and focused by the beam expander and focusing mirror, it is coupled to the optical fiber to irradiate the rail. the area to be measured on the surface to generate a photoacoustic signal;

The multi-element array ultrasonic probe, immersed in the coupling liquid, is used to collect the photoacoustic signal of the area to be tested on the surface of the rail, and the ultrasonic echo signal deeper in the area, and the collected photoacoustic signal and ultrasonic echo signal transmitted to the multi-channel parallel acquisition circuit;

The multi-channel parallel acquisition circuit preprocesses the optical signal, photoacoustic signal and ultrasonic echo signal and then uploads it to the computer;

The computer determines the spatial distribution information and surface damage type of the rail surface damage, the spatial distribution information and the shallow damage type of the rail shallow damage according to the received optical signal, photoacoustic signal and ultrasonic echo signal, As well as the spatial distribution information and deep damage types of the deep damage of the rail, and three-dimensional reconstruction of the rail to be tested.

Optionally, the device also includes:

The servo motor drive platform is used to carry and fix the light source, CCD camera, optical fiber and multi-element array ultrasonic probe, and under the control of the multi-channel parallel acquisition circuit, the light source, CCD camera, optical fiber and multi-element array ultrasonic probe Probe for position control.

Optionally, the pulse laser generated by the pulse laser has a wavelength of 532nm and a pulse width of 6nm.

The beneficial effects of the present invention are:

The multimodal signal detection method and device for rail defects provided by the present invention have the following beneficial effects:

1. The present invention uses optical, photoacoustic and ultrasonic three-modal signals to detect the damage of the high-speed rail rail. The optical signal is used to first determine the position of the rail surface damage, and then the pulse laser and the multi-element ultrasonic probe are used to collect the data. Determining the photoacoustic signal of the shallow layer of the rail and the ultrasonic signal of the deep layer can detect the defects of the high-speed rail more thoroughly;

2. The present invention aims at the characteristics that rail defects almost all originate from the surface and develop inward. First, a CCD camera is used to collect optical signals on the surface of the high-speed rail rail to determine the distribution of rail damage, and then the photoacoustic signal and ultrasonic signal are used to determine The defects in the distribution area are shallow and internal, thus overcoming the shortcoming of low efficiency of comprehensive scanning by ordinary nondestructive testing methods;

3. Through the processing and fusion of the collected optical signals, photoacoustic signals and ultrasonic signals of the high-speed rail rails, the present invention finally establishes a three-dimensional model of the detected rails, which can more intuitively and vividly show the problems existing in the rails, thereby being more conducive to Develop a future maintenance plan.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to designate the same parts. In the attached picture:

Fig. 1 is a flow chart of a multimodal signal detection method for rail defects proposed in an embodiment of the present invention;

2 is a logical schematic diagram of a multi-modal signal detection method for rail defects proposed by an embodiment of the present invention;

Fig. 3 is the schematic diagram of the acquisition area of the three modal signals of the high-speed rail rail proposed by the embodiment of the present invention;

Fig. 4 is the high-speed rail rail surface optical signal that CCD camera gathers in the embodiment of the present invention;

Fig. 5 is the (rail surface) laser scanning area determined according to the spatial distribution of surface defects in an embodiment of the present invention;

Fig. 6 is a schematic diagram of the photoacoustic signal of the high-speed rail rail collected by the multi-element array ultrasonic probe in the embodiment of the present invention;

Fig. 7 is a photoacoustic image at different depths of the shallow layer of the rail in the embodiment of the present invention;

Fig. 8 is an ultrasonic image of a rail internal crack at a depth of 1 mm in an embodiment of the present invention;

Fig. 9 is an ultrasonic image of a rail internal crack at a depth of 2 mm in an embodiment of the present invention;

Fig. 10 is an ultrasonic image of a rail internal crack at a depth of 3 mm in an embodiment of the present invention;

Fig. 11 is an ultrasonic image of a rail internal crack at a depth of 4 mm in an embodiment of the present invention;

Fig. 12 is an ultrasonic image of a rail internal crack at a depth of 5 mm in an embodiment of the present invention;

Fig. 13 is an ultrasonic image of a rail internal crack at a depth of 6 mm in an embodiment of the present invention;

Fig. 14 is a schematic structural diagram of a multi-modal signal detection device for rail defects proposed by an embodiment of the present invention.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

Those skilled in the art will understand that unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of said features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements, components, and/or groups thereof.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention belongs. It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be used in an idealized or overly formal sense unless specifically defined to explain.

Fig. 1 shows a flow chart of a multi-modal signal detection method for rail defects according to an embodiment of the present invention.

Referring to Fig. 1, the multimodal signal detection method of the rail defect proposed by the embodiment of the present invention specifically includes the following steps:

S11. Obtain the optical signal of the area to be tested on the surface of the rail to be tested, and determine the spatial distribution information and the type of surface damage of the rail surface according to the optical signal;

In practical applications, the CCD camera is used to obtain the optical signal on the surface of the rail to be tested, and uploaded to the computer for processing to determine the spatial distribution information such as the position, size, and extension direction of the rail surface damage, as well as the type of surface damage; among them, the rail can be For high-speed rail rails, subway rails, etc.

S12. Obtain the photoacoustic signal of the area where the rail surface damage is located, and determine the spatial distribution information and shallow damage type of the rail shallow damage according to the photoacoustic signal;

Specifically, the step S12 specifically includes:

Obtaining a photoacoustic signal generated in the area where the rail surface damage is located, performing image reconstruction according to the photoacoustic signal, and obtaining a photoacoustic image;

The photoacoustic image is processed and analyzed to determine the spatial distribution information of the shallow damage of the rail and the type of the shallow damage.

Among them, image reconstruction specifically refers to using the collected photoacoustic signal amplitude of each point to be measured to characterize the light absorption intensity of the point on the rail surface, so as to obtain the surface light absorption distribution of the entire area to be measured.

In practical application, pulsed laser is used to scan the location of the surface damage and the nearby area to generate photoacoustic signals, which are collected synchronously by multi-array ultrasonic probes and uploaded to the computer to determine the spatial distribution information and type of shallow damage on the rail.

S13. Obtain the ultrasonic echo signals of the location area where the shallow damage of the rail is located and the deeper area, and determine the spatial distribution information and the type of deep damage of the rail according to the ultrasonic echo signals;

In practical application, the multi-element array ultrasonic probe is used to scan the area near the shallow damage position and the deeper area, and the ultrasonic echo signal is received and uploaded to the computer for processing to determine the spatial distribution and type of deep rail damage.

S14. According to the spatial distribution information and surface damage type of rail surface damage, the spatial distribution information and shallow damage type of rail shallow damage, and the spatial distribution information and deep damage type of rail deep damage, the to-be-treated 3D reconstruction of the measured rail.

The multi-modal signal detection method for rail defects proposed in the embodiment of the present invention overcomes the problems of limited detection range and low detection efficiency in the existing non-destructive detection technology for detection of rail surface defects, and effectively improves the accuracy of detection results and efficiency, it can show the defects of the rail more intuitively and vividly.

The processing logic of the multi-modal signal detection method for rail defects proposed in the embodiment of the present invention, as shown in Figure 2, includes steps such as signal acquisition, signal sampling, computer processing, determination of defect information, information fusion, and establishment of a three-dimensional model, as follows :

Step 1. Use the CCD camera to obtain the optical signal on the surface of the high-speed rail rail, upload it to the computer for processing, and determine the spatial distribution information such as the position, size, and extension direction of the rail surface damage, as well as the type of surface damage;

Step 2. Use pulsed laser to scan the location of the surface damage and the nearby area, generate photoacoustic signals and use multi-element array ultrasonic probes to collect them synchronously, upload them to the computer, and determine the spatial distribution information and types of shallow damage on the rail;

Step 3. Use the multi-element array ultrasonic probe to scan the area near the shallow damage position and the deeper area, receive the ultrasonic echo signal and upload it to the computer for processing, and determine the spatial distribution and type of the deep damage of the rail;

Step 4. Correct the defect spatial distribution according to the damage spatial distribution information of the rail surface, shallow layer and deep layer, and correct the defect type according to the damage type of the rail surface, shallow layer and deep layer, and integrate optical, photoacoustic and ultrasonic Inspection data, 3D reconstruction of rail and damage.

Fig. 3 is a schematic diagram of the acquisition area of the three modal signals of the high-speed rail rail proposed by the embodiment of the present invention. As shown in Fig. 3, the embodiment of the present invention realizes all-round detection of rail surface, shallow and deep defects, and expands the detection Scope; on the computer, the signals of optical, photoacoustic and ultrasonic modes of high-speed rail rails are integrated for processing, and a three-dimensional model of the detected rail is established, which effectively improves the accuracy and efficiency of the detection results, and can display the rail more intuitively and vividly. The existing problems of the rails are more conducive to the formulation of later maintenance plans. The device has strong adaptability and a wide range of applications.

Taking the detection of surface defects of high-speed rail rails as an example, the method for detecting surface defects of rails based on photoacoustic signals proposed in the embodiment of the present invention will be described in detail below.

The optical signal of the high-speed rail rail collected by the CCD camera is shown in Figure 4. The optical signal is processed by a computer, and the shape and distribution parameters of each surface defect are shown in Table 1. The size, position and inclination angle of each surface defect can be detected with sufficient precision. On the basis of the detection value of the surface defect position, a certain margin is taken on the left and right sides, and the scanning range of the laser on the rail (surface) is obtained, as shown in Figure 5. The photoacoustic signal data obtained after the pulsed laser scans the rail contains information in three dimensions (length, width, and depth), as shown in Figure 6. The rail damage information at different depths can be obtained by taking data at different depths from the photoacoustic signal. The defect photoacoustic image in Figure 7 vividly shows the crack defect shape at different depths in the shallow layer of the rail. According to the same processing method, the collected ultrasonic signals inside the rail are processed, and the ultrasonic images of crack defects at different depths are obtained as shown in Figure 8-13. Using the spatial distribution of rail defects as an index, the surface, shallow and internal defect information is fused to obtain complete information on the spatial shape of rail defects.

Table 1 The shape and distribution parameters of surface defects

Fig. 14 shows a schematic structural diagram of a multi-modal signal detection device for rail defects proposed by an embodiment of the present invention;

Referring to Figure 14, the multimodal signal detection device for rail defects proposed in the embodiment of the present invention specifically includes:

Light source 1, CCD camera 2, optical fiber 4, focusing mirror 5, multi-element array ultrasonic probe 6, beam expander mirror 7, pulse laser 8, multi-channel parallel acquisition circuit 9 and computer 10; said light source 1, CCD camera 2, pulse laser 8. The multi-element array ultrasonic probe 6 is respectively connected to the control end of the multi-channel parallel acquisition circuit 9, and the multi-channel parallel acquisition circuit 9 is connected to the computer 10;

The light source 1 is used to illuminate the rail 3 to be tested;

The CCD camera 2 is used to collect the optical signal of the area to be measured on the surface of the rail 3 to be tested, and transmit the collected optical signal to the multi-channel parallel acquisition circuit 9;

The pulsed laser 8 is used to generate a pulsed laser that scans the area to be measured on the surface of the rail. The pulsed laser is coupled to the optical fiber after being expanded and focused by the beam expander 7 and the focusing mirror 5 in sequence. 4. Irradiate the area to be tested on the surface of the rail to generate a photoacoustic signal;

The multi-element array ultrasonic probe 6 is immersed in the coupling liquid, and is used to collect the photoacoustic signal of the area to be tested on the surface of the rail, and the ultrasonic echo signal deeper in the area, and the collected photoacoustic signal and ultrasonic echo The signal is transmitted to the multi-channel parallel acquisition circuit 9;

The multi-channel parallel acquisition circuit 9 preprocesses the optical signal, photoacoustic signal and ultrasonic echo signal and uploads it to the computer 10;

According to the received optical signal, photoacoustic signal and ultrasonic echo signal, the computer 10 determines the spatial distribution information and surface damage type of rail surface damage, the spatial distribution information and shallow damage type of rail shallow damage , as well as the spatial distribution information and deep damage types of rail deep damage, and perform three-dimensional reconstruction of the rail to be tested.

In the embodiment of the present invention, the rail 3 to be tested and the multi-element array ultrasonic probe 6 are both immersed in the coupling liquid.

In the embodiment of the present invention, the multi-channel parallel acquisition circuit controls the brightness and irradiation angle of the light source according to the actual working environment, and at the same time controls the CCD camera to obtain the optical signal on the surface of the high-speed rail rail with a high signal-to-noise ratio. The multi-channel parallel acquisition circuit controls the pulse laser to emit laser pulses, which are processed by the laser processing device and irradiated onto the rail. The multiple-array ultrasonic probe is placed near the laser irradiation spot, and is controlled by a multi-channel parallel acquisition circuit to transmit ultrasonic signals to the rail and receive ultrasonic and photoacoustic signals. The optical, photoacoustic and ultrasonic signals are processed by a multi-channel parallel acquisition circuit and then transmitted to the computer. The computer further processes and fuses the three modal signals to obtain the spatial distribution information of the surface, shallow and internal defects of the high-speed rail. and type information, and perform 3D reconstruction of the detected rail. It overcomes the problems of limited detection range and low detection efficiency in the existing non-destructive testing technology for rail surface defect detection technology, effectively improves the accuracy and efficiency of detection results, and can display the defects of the rail more intuitively and vividly.

Further, the device also includes: a servo motor drive platform 11;

The servo motor drive platform 11 is used to carry and fix the light source 1, CCD camera 2, optical fiber 4 and multi-element array ultrasonic probe 6, and under the control of the multi-channel parallel acquisition circuit 9, the light source 1, CCD Camera 2, optical fiber 4 and multi-element array ultrasonic probe 6 perform position control.

Specifically, in the embodiment of the present invention, the servo motor drive platform 11 is mechanically connected with the light source 1 , the CCD camera 2 , the optical fiber 4 and the multi-element array ultrasonic probe 6 . The servo motor drive platform 11 can control the translation of the light source 1 along the X and Y directions, and make a rotation of -30° to 30° along the rotation axis, so as to ensure that the light intensity and the irradiation angle can enable the CCD camera 2 to collect images with a high signal-to-noise ratio. optical signal. The CCD camera 2, the optical fiber 4 and the multi-element array ultrasonic probe 6 can translate and move along the three directions of X, Y and Z under the control of the servo motor drive platform 11, so that photoacoustic and ultrasonic signals with high signal-to-noise ratio can be collected.

Specifically, the multi-channel parallel acquisition circuit 9 includes: a main control circuit 91, a TGC amplifier circuit 92, a pre-filter circuit 93, an A/D sampling circuit 94, a data acquisition circuit 95 and a data transmission circuit 96;

Described TGC amplifying circuit 92, pre-filter circuit 93, A/D sampling circuit 94, data acquisition circuit 95 and data transmission circuit 96 are electrically connected successively, and described main control circuit 91 is respectively connected with TGC amplifying circuit 92, A/D sampling circuit 94. The data acquisition circuit 95 is electrically connected to the data transmission circuit 96;

The TGC amplifying circuit 92, the pre-filtering circuit 93 and the A/D sampling circuit 94 sequentially amplify, filter and AD convert the photoacoustic signal collected by the multi-element array ultrasonic probe 6, and sample the analog signal after the AD conversion , to obtain an analog sampling signal of the photoacoustic signal, and upload the analog sampling signal to the computer 10 through the data acquisition circuit 95 and the data transmission circuit 96 .

Wherein, the data acquisition circuit is a data acquisition circuit based on a field programmable gate array FPGA chip. The data transmission circuit is specifically: a USB data transmission circuit.

In the embodiment of the present invention, the CCD camera is a P2-22-06K40 line scan camera of the DALSA Piranha26k series.

The pulsed laser 8 is a Q-Switched Nd:YAG pulsed laser. The pulsed laser generated by the pulsed laser has an energy density of 10 mJ, a wavelength of 532 nm, a pulse width of 6 ns, and a repetition rate of 15 Hz.

The multi-element array ultrasonic probe 6 is a broadband linear array probe with 128 array elements, the probe bandwidth is 5-10 MHz, and the array element spacing is 0.3 mm.

TGC amplifying circuit 92 adopts the AD8332 of ADI Company; ADS5270 of TI Company that the A/D converter in the A/D sampling circuit 94 adopts; FPGA selects EP2C35F672 of ALTERA Company in the data acquisition circuit 95; USB chip selects among the data transmission circuit 96 EZ-USB FX2LP from Cypress.

The multi-modal signal detection device for rail defects provided by the embodiments of the present invention can successfully detect the spatial distribution and types of rail surface, shallow and internal defects. The device uses a DALSA P2-22-06K40 line scan camera to collect optical signals on the surface of high-speed rail rails; a pulsed laser with an energy density of 10mJ and a wavelength of 532nm is used to excite photoacoustic signals on the shallow layer of the rail; a 128-element broadband line array probe is used to collect Photoacoustic and ultrasonic signals. The three modal signals are centrally processed in the computer to obtain comprehensive high-speed rail defect information. Compared with the existing detection methods, the system uses three modes of optical, photoacoustic and ultrasonic signals to detect the damage of high-speed rail rails, which can detect the defects of high-speed rail rails more thoroughly; and for almost all rail defects originate from the surface And the characteristics of inward development, first use the CCD camera to collect the optical signal on the surface of the high-speed rail rail to determine the distribution of rail damage, reduce the scanning range, thereby greatly improving the detection efficiency; finally establish a three-dimensional model of the detected rail, which can be more intuitive It can more vividly show the existing problems of the rail, which is more conducive to formulating a later maintenance plan.

The working principle of the present invention is: the main control circuit sends a pulse signal to the light source and the CCD camera, collects the optical signal on the surface of the rail, and uploads it to the main control circuit, and then the main control circuit transmits the optical signal to the TGC amplifier for signal amplification, and then the The preset filter circuit filters the noise, and after A/D conversion and sampling, it is transmitted to the computer by the data transmission circuit for processing.

After the computer uses the optical signal to determine the position of the surface defect, the main control platform of the multi-channel parallel acquisition circuit sends an excitation pulse signal to the pulse laser, and controls the servo motor drive platform to change the position of the optical fiber and the multi-element array ultrasonic probe to excite the photoacoustic sound at the defect. At the same time, the main control circuit sends pulses to the multi-element array ultrasonic probe to collect the excited rail shallow layer photoacoustic signal. The photoacoustic signal is directly transmitted to the TGC amplifier, and then uploaded to the computer according to the above optical signal transmission process.

The computer processes the photoacoustic signal to obtain the spatial distribution and type information of the shallow defects of the rail, and sends instructions to the main control platform according to the spatial distribution information. The main control platform controls the multi-element array ultrasonic probe to change the position through the servo motor drive platform, and then emits the ultrasonic probe to the inside of the rail. Ultrasound, and receive the echo signal, the collected ultrasonic signal inside the rail is uploaded to the computer according to the path of photoacoustic signal propagation. So far, the signals of the three modes are all uploaded to the computer for processing and fusion to obtain more detailed rail defect information.

The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Those of ordinary skill in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all Equivalent technical solutions also belong to the category of the present invention, and the scope of patent protection of the present invention should be defined by the claims.

Claims (6)

1. a multimodal signal detection method of rail defect, is characterized in that, described method comprises: Step 1, obtaining the optical signal of the area to be tested on the surface of the rail to be tested, and determining the spatial distribution information and the type of surface damage of the rail surface according to the optical signal; Step 2, obtaining the photoacoustic signal of the area where the rail surface damage is located, and determining the spatial distribution information and shallow damage type of the rail shallow damage according to the photoacoustic signal; Step 3, obtaining the ultrasonic echo signals of the position area where the shallow layer damage of the rail is located and the deeper area, and determining the spatial distribution information and the type of deep damage of the rail according to the ultrasonic echo signal; Step 4, according to the spatial distribution information and surface damage type of rail surface damage, the spatial distribution information and shallow damage type of rail shallow damage, and the spatial distribution information and deep damage type of rail deep damage, the Three-dimensional reconstruction of the rail to be tested. 2. The method according to claim 1, characterized in that the photoacoustic signal of the position area where the rail surface damage is located is acquired, and according to the photoacoustic signal, the spatial distribution information and the shallow layer damage of the rail are determined. Layer damage types, including: Obtaining a photoacoustic signal generated in the area where the rail surface damage is located, performing image reconstruction according to the photoacoustic signal, and obtaining a photoacoustic image; The photoacoustic image is processed and analyzed to determine the spatial distribution information of the shallow damage of the rail and the type of the shallow damage. 3 . The method according to claim 1 , wherein the spatial distribution information of the rail surface damage includes: the position, size, and extension direction of the rail surface damage. 4 . 4. A multimodal signal detection device for rail defects according to any one of claims 1 to 3, wherein said device comprises: a light source, a CCD camera, an optical fiber, a focusing mirror, a multi-element array ultrasonic probe, Pulse laser, beam expander, multi-channel parallel acquisition circuit and computer; the light source, CCD camera, pulse laser, multi-element array ultrasonic probe are respectively connected to the control end of the multi-channel parallel acquisition circuit, the multi-channel parallel acquisition circuit connected to said computer; The light source is used to irradiate the rail to be tested; The CCD camera is used to collect optical signals of the area to be tested on the surface of the rail to be tested, and transmit the collected optical signals to the multi-channel parallel acquisition circuit; The pulsed laser is used to generate a pulsed laser that scans the area to be measured on the surface of the rail. After the pulsed laser is sequentially expanded and focused by the beam expander and focusing mirror, it is coupled to the optical fiber to irradiate the rail. the area to be measured on the surface to generate a photoacoustic signal; The multi-element array ultrasonic probe is used to collect the photoacoustic signal of the area to be tested on the surface of the rail, and the ultrasonic echo signal deeper in the area, and transmit the collected photoacoustic signal and ultrasonic echo signal to the multiple Channel parallel acquisition circuit; The multi-channel parallel acquisition circuit preprocesses the optical signal, photoacoustic signal and ultrasonic echo signal and then uploads it to the computer; The computer determines the spatial distribution information and surface damage type of the rail surface damage, the spatial distribution information and the shallow damage type of the rail shallow damage according to the received optical signal, photoacoustic signal and ultrasonic echo signal, As well as the spatial distribution information and deep damage types of the deep damage of the rail, and three-dimensional reconstruction of the rail to be tested. 5. The device according to claim 4, further comprising: The servo motor drive platform is used to carry and fix the light source, CCD camera, optical fiber and multi-element array ultrasonic probe, and under the control of the multi-channel parallel acquisition circuit, the light source, CCD camera, optical fiber and multi-element array ultrasonic probe Probe for position control. 6. The device according to claim 4, characterized in that the pulse laser generated by the pulse laser has a wavelength of 532nm and a pulse width of 6nm.