CN116930118A - Bronze ware detection system and detection method - Google Patents

Bronze ware detection system and detection method Download PDF

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Publication number
CN116930118A
CN116930118A CN202310913343.6A CN202310913343A CN116930118A CN 116930118 A CN116930118 A CN 116930118A CN 202310913343 A CN202310913343 A CN 202310913343A CN 116930118 A CN116930118 A CN 116930118A
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detected
point cloud
layer
rust
mobile unit
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王镜惠
胡旻
张晓秋艳
谢振斌
郭建波
张晖
肖庆
张思源
韦元培
李博扬
宾泽川
王冲
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University of Electronic Science and Technology of China
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/0002—Inspection of images, e.g. flaw detection
    • G06T7/0004—Industrial image inspection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
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    • G—PHYSICS
    • G01—MEASURING; TESTING
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    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
    • G01N21/3586—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation by Terahertz time domain spectroscopy [THz-TDS]
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    • G06T2207/00—Indexing scheme for image analysis or image enhancement
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Abstract

The invention discloses a bronze ware detection system and a detection method, which relate to the field of terahertz application and comprise the following steps: terahertz time-domain spectrometer, structure light camera, processor, mobile unit and control unit; the terahertz time-domain spectrometer transmits a detection signal to an object to be detected, receives the reflected signal and transmits the reflected signal to the processor, and the processor calculates and obtains the type of the rusting layer and the thickness of each rusting layer on the object to be detected; the mobile unit carries the probe to move and scans and detects the surface of the object to be detected; the structured light camera performs imaging on the surface of the object to be detected to establish a depth map, converts the depth map into point cloud data to obtain a point cloud map of the surface of the object to be detected, and calculates and obtains normal data of the surface of the object to be detected based on the point cloud map; the control unit establishes a world coordinate system, generates a moving track of the moving unit based on the world coordinate system and normal data, controls the moving unit to move, and finishes scanning an object to be detected.

Description

Bronze ware detection system and detection method
Technical Field
The invention relates to the field of detection, in particular to a bronze ware detection system and a bronze ware detection method.
Background
In recent years, the protection of cultural relics becomes a focus problem, and the key point of the protection of cultural relics is that the accurate detection of the cultural relics is that the surface components and the thickness of each layer of the cultural relics need to be analyzed, and then a targeted cultural relic protection means is determined, so that the purpose of scientifically protecting the cultural relics is achieved, and the aim of the conventional technical means is difficult to achieve.
The existing common cultural relic detection technology comprises X-ray fluorescence spectrum analysis and Raman spectrum analysis, and the two methods are respectively characterized in detecting the cultural relics, but cannot meet the requirements of scientific cultural relic protection. The X-ray fluorescence spectrum analysis is commonly used for ancient remains in ages, textures, components and the like, and the X-ray fluorescence spectrum analysis cannot perform layered imaging on components of each layer of the cultural relics due to the strong penetrability of the X-ray; the raman spectrum is used as an analysis means with high sensitivity, rapidness, convenience, no damage and capability of carrying out micro-area detection on a substance structure, and in recent years, application research in various cultural relics identification, repair and archaeology is very active, but the raman spectrum cannot carry out layered imaging on the cultural relics, and the imaging area is smaller, so that the requirements of scientific cultural relics protection cannot be met.
Disclosure of Invention
In order to enable large area layered imaging detection of bronze relics, the present invention provides a bronze detection system comprising:
terahertz time-domain spectrometer, structure light camera, processor, mobile unit and control unit;
the terahertz time-domain spectrometer is used for transmitting detection signals to an object to be detected, receiving reflected signals reflected back from the object to be detected, transmitting the reflected signals to the processor, and calculating and obtaining the type of the rusting layer and the thickness of each rusting layer on the object to be detected based on the reflected signals;
the mobile unit is used for carrying the probe of the terahertz time-domain spectrometer to move and scan and detect the surface of the object to be detected;
the processor is further used for establishing a depth map based on an imaging result, converting the depth map into point cloud data, obtaining a point cloud map of the surface of the object to be detected based on the point cloud data, and obtaining normal data of the surface of the object to be detected based on calculation of the point cloud map;
and importing the normal data into a control unit, wherein the control unit is used for establishing a world coordinate system based on the position information of the mobile unit, the position information of the structured light camera and the position information of the object to be detected, generating a moving track of the mobile unit based on the world coordinate system and the normal data, and controlling the mobile unit to move based on the moving track control unit so as to finish scanning the object to be detected.
When terahertz waves are struck on the surfaces of relics such as bronze wares, part of signals are reflected, and object components can be obtained according to the reflected signals; the other part of the signals can continue to go deep, a part of the signals can be continuously reflected on the next layer, the thickness of the layer can be calculated according to the refractive index and the flight time, in order to further enlarge the measuring area, a terahertz detection system is jointly built through a terahertz time-domain spectrometer (THz-TDS), large-scale continuous three-dimensional imaging can be achieved, detection of bronze components is achieved, and thickness measurement of each layer is achieved.
In some embodiments, the structured light camera is a binocular camera. The structured light camera is a camera developed by simulating human eyes, has imaging principles similar to human vision, and has better 3D imaging effect than the traditional camera.
In some embodiments, the point cloud data is subjected to denoising, filtering and slicing operations to obtain a point cloud image of the surface of the object to be detected. Because the structured light camera has some noise points and discrete points in the imaging process, the noise points and the discrete points need to be removed when the point cloud image is generated, denoising and filtering operations can be performed, and the subsequent operation can be facilitated by slicing.
In some embodiments, the mobile unit is a mechanical arm, and the movement control of the probe can be intelligently, rapidly and accurately realized through the mechanical arm.
In some embodiments, the control unit is further configured to control a hover duration of the mobile unit. The accuracy and the efficiency of the detection can be effectively improved through the control of the hovering time length, the hovering time length is increased when the detection does not reach the effect yet, and the hovering movement to the next measuring point is ended when the detection reaches the purpose.
In some embodiments, the type of each rust layer on the object to be inspected is calculated as follows:
intercepting and obtaining a plurality of reflected pulse signals and time sequencing information thereof from the reflected signals, wherein the reflected pulse signals correspond to the rust layers one by one;
transforming the reflected pulse signal to a frequency domain to obtain an absorption spectrum of a corresponding rust layer, and obtaining the rust type of the rust layer based on the absorption spectrum;
and obtaining the type and the position relation of each rusting layer in the rusting area of the object to be detected based on the rusting types of the corresponding rusting layers of the reflected pulse signals and time sequencing information among the reflected pulse signals.
Different from the traditional detection mode, the invention adopts a terahertz detection mode, and terahertz has various advantages in the aspect of nondestructive detection. Terahertz waves not only have good penetrability to many dielectric materials and nonpolar substances, but also have high transverse resolution due to shorter wavelength than microwaves. Meanwhile, the photon energy of the terahertz wave is only milli-electron volt order, and harmful ionization reaction is not caused.
The method comprises the steps of obtaining a plurality of reflected pulse signals and time sequencing information thereof from reflected signals, and on one hand, converting the reflected pulse signals into a frequency domain to obtain absorption spectra of corresponding corrosion layers, and comparing the absorption spectra with corresponding frequency spectrum databases to obtain corrosion types of the corrosion layers; on the other hand, based on time ordering information among a plurality of reflected pulse signals, the spatial position relation of each corrosion layer in the corrosion area of the object to be detected can be obtained, and then the type and the position relation of each corrosion layer in the corrosion area of the object to be detected can be obtained.
In some embodiments, the thickness of each rust layer on the object to be inspected is calculated as follows:
intercepting and obtaining a plurality of reflected pulse signals and time sequencing information thereof from the reflected signals, wherein the reflected pulse signals correspond to the rust layers one by one;
based on time sequencing information of a plurality of reflected pulse signals, time delay information between 2 adjacent reflected pulse signals is obtained, a plurality of pieces of time delay information are obtained in an accumulated mode, and the time delay information corresponds to the rust layer one by one;
calculating the thickness of the rust layer based on the time delay information and the rust type of the corresponding rust layer;
the thickness of all the rust layers was obtained.
The principle of the thickness obtaining is that signals are returned every time terahertz irradiates on one layer of corrosion layer, the distance and time difference between two adjacent returned signals are utilized, and the thickness of each layer of corrosion layer can be calculated by utilizing the time difference and the propagation speed of the signals in a medium, so that the method not only can obtain the total number of layers of corrosion layers, but also can obtain the thickness of each layer of corrosion layer and the distribution in space.
In some embodiments, the thickness of the rust layer is calculated by:
wherein d is the thickness of the rust layer, Δt is the time delay information corresponding to the rust layer, c is the light speed, n s Is the refractive index of the rusting layer.
In some embodiments, the system further comprises a sample placement stage for placing an object to be inspected.
The invention also provides a detection method based on the bronze ware detection system, which comprises the following steps:
step 1: constructing an optical path of the terahertz time-domain spectrometer, and clamping the terahertz time-domain spectrometer on the mobile unit;
step 2: fixing an object to be detected on a sample placing table;
step 3: imaging an object to be detected by using a structured light camera, establishing a depth map based on an imaging result, converting the depth map into point cloud data, obtaining a point cloud map of the surface of the object to be detected based on the point cloud data, and obtaining normal data of the surface of the object to be detected based on calculation of the point cloud map;
step 4: importing the normal data into a control unit, wherein the control unit establishes a world coordinate system based on the position information of the mobile unit, the position information of the structured light camera and the position information of the object to be detected, and generates a moving track of the mobile unit based on the world coordinate system and the normal data;
step 5: and controlling the mobile unit to move based on the movement track control unit to finish scanning the object to be detected.
The one or more technical schemes provided by the invention have at least the following technical effects or advantages:
the invention can realize large-area automatic continuous detection of the sample.
The invention can realize the detection of the position and thickness of each layer of the rust layer on the surface of the sample, and can realize nondestructive detection.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention;
FIG. 1 is a schematic diagram of a bronze ware inspection system;
FIG. 2 is a schematic diagram of the optical path of a bronze ware detecting system;
FIG. 3 is a schematic workflow diagram of a robotic arm and a structured light camera;
the device comprises a 1-binocular camera, a 2-sample stage, a 3-bronze cultural relic sample, a 4-computer, a 5-mechanical arm, a 6-probe, a transmitting end of a 7-photoconductive antenna, an 8-focusing lens and a receiving end of a 9-photoconductive antenna.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention will be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without collision.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than within the scope of the description, and the scope of the invention is therefore not limited to the specific embodiments disclosed below.
Example 1
Referring to fig. 1, fig. 1 is a schematic diagram illustrating a bronze ware detecting system, and in accordance with a first embodiment of the present invention, a bronze ware detecting system is provided, the system includes:
terahertz time-domain spectrometer, structure light camera, processor, mobile unit and control unit;
the terahertz time-domain spectrometer is used for transmitting detection signals to an object to be detected, receiving reflected signals reflected back from the object to be detected, transmitting the reflected signals to the processor, and calculating and obtaining the type of the rusting layer and the thickness of each rusting layer on the object to be detected based on the reflected signals;
the mobile unit is used for carrying the probe of the terahertz time-domain spectrometer to move and scan and detect the surface of the object to be detected;
the processor is further used for establishing a depth map based on an imaging result, converting the depth map into point cloud data, obtaining a point cloud map of the surface of the object to be detected based on the point cloud data, and obtaining normal data of the surface of the object to be detected based on calculation of the point cloud map;
and importing the normal data into a control unit, wherein the control unit is used for establishing a world coordinate system based on the position information of the mobile unit, the position information of the structured light camera and the position information of the object to be detected, generating a moving track of the mobile unit based on the world coordinate system and the normal data, and controlling the mobile unit to move based on the moving track control unit so as to finish scanning the object to be detected.
Terahertz (THz) waves generally refer to electromagnetic waves with the frequency of 100 GHz-10 THz and the wavelength of 30-3000 mu m, are positioned between millimeter waves and far infrared rays in an electromagnetic wave spectrum, have low radiation and strong penetrability, and have optical properties of easily generating resonance with biological and semiconductor materials, and the characteristics enable the Terahertz near-field imaging technology to be widely applied to the fields of security, chemical identification, medical imaging, quality control and the like. The terahertz technology has great advantages in the field of cultural relics protection, in particular to painting cultural relics, and has the capability of lacking nondestructive analysis means such as an x-ray fluorescence spectrum, an infrared spectrum and the like, namely, the terahertz detection technology is the only technology capable of nondestructive detection of the thickness of each layer on the surface of the bronze ware at present. The terahertz photon energy is low, ionization can not be generated when the terahertz photon energy irradiates on the surfaces of cultural relics such as bronze wares, and therefore the cultural relics can not be damaged; the rotation energy level and vibration of a plurality of substances are in the terahertz frequency band, so that terahertz detection can be used, a terahertz characteristic peak database of a plurality of pigments is relatively perfect, and the characteristic peaks can be conveniently compared to detect pigment components.
When terahertz waves are struck on the surfaces of relics such as bronze wares, part of signals are reflected, and object components can be obtained according to the reflected signals; another part of the signal continues to go deep, and a part of the signal continues to be reflected in the next layer, and the thickness of the layer can be calculated according to the refractive index, the flight time and the incidence angle. In order to expand the measurement area, the system uses a binocular camera, a mechanical arm and other devices, and a terahertz detection system is built through the combination of a robot studio and a terahertz time-domain spectrometer (THz-TDS), so that large-scale continuous three-dimensional imaging can be realized, detection of bronze ware components and measurement of thickness of each layer are completed, and the result can meet the requirements of scientific cultural relic protection on cultural relic detection.
The system structure is shown in fig. 1, a binocular camera 1 is used for imaging a bronze relic sample 3 placed on a sample table 2, generating a point cloud image of the surface of the bronze relic sample 3 on a computer 4, calculating the normal of each point on the surface of the bronze relic sample 3, calibrating a mechanical arm 5 through the binocular camera 1, completing the establishment of a world coordinate system, planning a moving route of the mechanical arm through the calculated normal and the world coordinate system, finally fixing a probe 6 to the tail end of the mechanical arm for emitting a terahertz detection light path, emitting femtosecond laser pulses from a femtosecond laser at the emitting end of a photoconductive antenna, vertically incident to the surface of the bronze relic sample 3, finally, enabling a reflected signal to be beaten on the probe 6, feeding back to the computer after a scanning result is obtained, controlling the hovering time of the mechanical arm according to the result, and finally completing the detection of the bronze device through the processing of the obtained data.
The scanning of a small area by the TDS scanning eye-shaper requires a certain integration time, and the scanning of a small area can be completed after a certain integration time, so that the hovering time needs to be controlled. After the scanning is completed, the software of the TDS can see that the scanning is completed, namely the hover time is reached, and at the moment, a signal is sent to the mechanical arm through a time length control program or module, so that the mechanical arm continues to move, and the next point is measured.
The suspension time control mode in the invention can write a time length control program by labview, the TDS needs an integration time to finish scanning a small area when scanning the bronze, then the scanning result is presented on software matched with the TDS, and after the scanning of the small area is finished, an instruction is sent to the mechanical arm through the written time length control program to enable the mechanical arm to continue to move to the next area, and then the scanning is continued.
In the detection process, a specific system light path is shown in fig. 2, a femtosecond laser in the terahertz time-domain spectrometer emits a femtosecond laser wave with the wavelength of 1550nm, the femtosecond laser wave reaches a transmitting end 7 of a photoconductive antenna through an optical fiber delay line in the terahertz time-domain spectrometer, the femtosecond laser wave is focused by a focusing lens 8 and vertically enters the surface of a bronze sample, and due to complex substance components on the surface of the bronze sample, a part of the terahertz wave is reflected back between two layers, a receiving end 9 of the photoconductive antenna receives the signal, and the other part of the terahertz wave continuously enters the next layer. The terahertz signal reflected from the bronze device carries the characteristic information of the substance, the time domain signal is converted into a frequency domain through fft (fast Fourier transform), and the low-order signal is larger in noise, so that the low-order signal, the second-order signal and the third-order signal are considered simultaneously during analysis, errors are reduced, and the substance components can be obtained according to the positions of characteristic peaks by comparing spectral libraries of substances such as rust, pigment and the like; meanwhile, according to the difference of the flight time of the emitted signals, the substance known by the comparison spectrum library can be used for representing the transmission speed of light in the substance according to the formula v=c/n, wherein c is the transmission speed of light in vacuum, n is the refractive index of the substance, and the transmission speed of light in the substance can be obtained according to the transmission speed of light in the substance and the flight time, so that the layer thickness can be obtained according to the transmission speed of light in the substance.
The transmitting end and the receiving end of the photoconductive antenna in the embodiment are integrated in the probe, so that measurement is convenient.
The working principles of the mechanical arm and the structured light camera are shown in a flow chart 3, the structured light camera is a camera which simulates human eyes to develop, the imaging principle is similar to human vision, the imaging principle has better 3D imaging effect than that of the traditional camera, and because terahertz vertical incidence is required when measuring bronze ware components, the normal of the bronze ware surface needs to be calculated, and therefore, a binocular camera needs to be used for obtaining better 3D imaging results. The method comprises the steps of using a binocular camera to change the angle between a bronze ware and the camera, obtaining the surface shape of the bronze ware, using robottstudio simulation software to create a depth map through a stereoscopic vision algorithm, converting the depth map into point cloud data, obtaining the point cloud map of the bronze ware surface after operations such as denoising, filtering and slicing, calculating the normal line of the bronze ware surface according to the point cloud map by using a pcnormal function of matlab, and importing the data into a robot studio. The Pcnormals function is a calculation mode based on the least square method principle, the function can find a neighborhood point set of each point in the point cloud chart, a covariance matrix is constructed according to the neighborhood point set, a characteristic value and a characteristic vector of the covariance matrix are calculated, and finally, the normal vector of each point is the characteristic vector corresponding to the minimum characteristic value of the covariance matrix. And fixing the height of the mechanical arm, the positions of the binocular camera and the bronze ware sample, establishing a world coordinate system, planning a motion track of the mechanical arm on robottstudio software according to the calculated normal, establishing a detection light path, clamping a probe with a terahertz detection light path by the mechanical arm, opening a femtosecond laser, controlling the mechanical arm to move, starting scanning of the bronze ware point when the mechanical arm is above the bronze ware, completing the scanning process after a certain integral time, and completing the control of suspension time of the mechanical arm, thereby completing the whole three-dimensional scanning process.
The embodiment also provides a detection method based on the bronze ware detection system, which comprises the following steps:
step 1: constructing an optical path of the terahertz time-domain spectrometer, and clamping the terahertz time-domain spectrometer on the mobile unit;
step 2: fixing an object to be detected on a sample placing table;
step 3: imaging an object to be detected by using a structured light camera, establishing a depth map based on an imaging result, converting the depth map into point cloud data, obtaining a point cloud map of the surface of the object to be detected based on the point cloud data, and obtaining normal data of the surface of the object to be detected based on calculation of the point cloud map;
step 4: importing the normal data into a control unit, wherein the control unit establishes a world coordinate system based on the position information of the mobile unit, the position information of the structured light camera and the position information of the object to be detected, and generates a moving track of the mobile unit based on the world coordinate system and the normal data;
step 5: and controlling the mobile unit to move based on the movement track control unit to finish scanning the object to be detected.
By the method, the embodiment can realize continuous large-area scanning detection of the object to be detected and nondestructive detection of the object to be detected.
Example two
The present invention will be described with reference to specific examples on the basis of the first embodiment:
in the second example, the object to be detected is a bronze ware, specifically a first eye ware, as described in the first example, a binocular camera is used first, imaging is performed while changing the angle between the camera and the first eye ware, after imaging is completed, a robot simulation software robot studio is used, a depth map is created through a stereoscopic vision algorithm, then the depth map is converted into point cloud data, after operations such as denoising, filtering and slicing are performed, a bronze ware surface point cloud map can be obtained, according to the point cloud map, the following algorithm is used for calculating the point cloud map normal, the pcnormal is used for completing the estimation of the normal, the point cloud coordinate is represented by (x, y, z), the point cloud normal is represented by (u, v, w), after the calculation of the normal is completed, an anti-tangential value is calculated by using an atan2 function, whether the normal is in the same direction or not is judged, finally, the calculated point cloud map normal is checked by using a pcshow function, and the normal is derived after no error is ensured.
After data are imported into a robot studio, a movement track of a mechanical arm is planned, positions of a first eye-shaped device and a binocular camera of a bronze ware sample are fixed, the height of the mechanical arm is kept unchanged, a world coordinate system is established, a terahertz emission and detection light path is built and clamped by the mechanical arm, a femtosecond laser is opened, after a reflected signal is observed on a computer, the mechanical arm is controlled to move along the planned path, terahertz three-dimensional scanning of the bronze ware is completed, a scanning result is analyzed, lead-tin yellow exists on the surface of the first eye-shaped device, the existence of lead-tin yellow components is detected by using a Raman spectrum method, and the measuring result is verified; using the formula described above, the average thickness of the bronze surface rust layer was calculated to be 0.33mm.
Example III
The present invention will be described with reference to specific examples on the basis of the first embodiment:
in the second example, the object to be detected is a bronze ware, specifically a second eye-shaped ware, as described in the first example, 3D imaging of the second eye-shaped ware is completed by using a binocular camera, after a point cloud image of the second eye-shaped ware is obtained on a computer, a surface normal of the second eye-shaped ware is calculated, a mechanical arm path is planned, an optical path is built, the optical path is fixed to the mechanical arm, the positions of the second eye-shaped ware and the binocular camera are fixed, the height of the mechanical arm is kept unchanged, calibration is performed according to the camera, the mechanical arm and the tail end of the mechanical arm, a world coordinate system is established, a femtosecond laser is opened, the mechanical arm is controlled to move along a given route after a reflected signal is detected, and terahertz three-dimensional scanning of the second eye-shaped ware can be completed. Point imaging was performed for several specific points of the second eye surface, and by performing point imaging analysis on four points of the eye surface, the average time delay was 3.8ps, the refractive index was 1.8, the angle of incidence was 45 degrees, and the calculated thickness was about 0.22mm.
Example IV
On the basis of the first embodiment, the present embodiment can be applied to various types and thicknesses of the rusting layers of the bronze ware:
the type of each rust layer is calculated and obtained by the following mode:
intercepting and obtaining a plurality of reflected pulse signals and time sequencing information thereof from the reflected signals, wherein the reflected pulse signals correspond to the rust layers one by one;
transforming the time domain reflection pulse signal to a frequency domain to obtain an absorption spectrum of a corresponding rust layer, and obtaining the rust type of the rust layer based on the absorption spectrum;
and obtaining the type and the position relation of each rusting layer in the rusting area of the object to be detected based on the rusting types of the corresponding rusting layers of the reflected pulse signals and time sequencing information among the reflected pulse signals.
The thickness of each rust layer is calculated by the following method:
intercepting and obtaining a plurality of reflected pulse signals and time sequencing information thereof from the reflected signals, wherein the reflected pulse signals correspond to the rust layers one by one;
based on time sequencing information of a plurality of reflected pulse signals, time delay information between 2 adjacent reflected pulse signals is obtained, a plurality of pieces of time delay information are obtained in an accumulated mode, and the time delay information corresponds to the rust layer one by one;
calculating the thickness of the rust layer based on the time delay information and the rust type of the corresponding rust layer;
the thickness of all the rust layers was obtained.
In some embodiments, the thickness of the rust layer is calculated by:
wherein d is the thickness of the rust layer, Δt is the time delay information corresponding to the rust layer, c is the light speed, n s Is the refractive index of the rusting layer.
By the method, the corrosion type and the position of each layer corresponding to the corrosion layer can be obtained, and the thickness of each layer of corrosion layer can be obtained.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (10)

1. Bronze ware detecting system, characterized in that the system comprises:
terahertz time-domain spectrometer, structure light camera, processor, mobile unit and control unit;
the terahertz time-domain spectrometer is used for transmitting detection signals to an object to be detected, receiving reflected signals reflected back from the object to be detected, transmitting the reflected signals to the processor, and calculating and obtaining the type of the rusting layer and the thickness of each rusting layer on the object to be detected based on the reflected signals;
the mobile unit is used for carrying the probe of the terahertz time-domain spectrometer to move and scan and detect the surface of the object to be detected;
the processor is further used for establishing a depth map based on an imaging result, converting the depth map into point cloud data, obtaining a point cloud map of the surface of the object to be detected based on the point cloud data, and obtaining normal data of the surface of the object to be detected based on calculation of the point cloud map;
and importing the normal data into a control unit, wherein the control unit is used for establishing a world coordinate system based on the position information of the mobile unit, the position information of the structured light camera and the position information of the object to be detected, generating a moving track of the mobile unit based on the world coordinate system and the normal data, and controlling the mobile unit to move based on the moving track control unit so as to finish scanning the object to be detected.
2. The bronze ware detecting system according to claim 1, wherein the structured light camera is a binocular camera.
3. The bronze ware detecting system according to claim 1, wherein the point cloud image of the surface of the object to be detected is obtained after denoising and filtering the point cloud data.
4. The bronze ware detecting system according to claim 1, wherein the moving unit is a robotic arm.
5. The bronze detecting system according to claim 1, wherein the control unit is further configured to control a moving speed and a hover time period of the mobile unit.
6. The bronze ware detecting system according to claim 1, wherein the type of each rust layer on the object to be detected is calculated by:
intercepting and obtaining a plurality of reflected pulse signals and time sequencing information thereof from the reflected signals, wherein the reflected pulse signals correspond to the rust layers one by one;
transforming the reflected pulse signal to a frequency domain to obtain an absorption spectrum of a corresponding rust layer, and obtaining the rust type of the rust layer based on the absorption spectrum;
and obtaining the type and the position relation of each rusting layer in the rusting area of the object to be detected based on the rusting types of the corresponding rusting layers of the reflected pulse signals and time sequencing information among the reflected pulse signals.
7. The bronze ware according to claim 6, wherein the thickness of each rusted layer on the object to be inspected is calculated by:
intercepting and obtaining a plurality of reflected pulse signals and time sequencing information thereof from the reflected signals, wherein the reflected pulse signals correspond to the rust layers one by one;
based on time sequencing information of a plurality of reflected pulse signals, time delay information between 2 adjacent reflected pulse signals is obtained, a plurality of pieces of time delay information are obtained in an accumulated mode, and the time delay information corresponds to the rust layer one by one;
calculating the thickness of the rust layer based on the time delay information and the rust type of the corresponding rust layer;
the thickness of all the rust layers was obtained.
8. The bronze detecting system according to claim 7, wherein the thickness of the rusting layer is calculated by:
wherein d is the thickness of the rust layer, Δt is the time delay information corresponding to the rust layer, c is the light speed, n s Is the refractive index of the rusting layer.
9. The bronze ware testing system according to claim 1, further comprising a sample placement stage for placing an object to be tested.
10. A detection method based on the bronze ware detection system according to any one of claims 1 to 9, characterized in that the method comprises:
step 1: constructing an optical path of the terahertz time-domain spectrometer, and clamping the terahertz time-domain spectrometer on the mobile unit;
step 2: fixing an object to be detected on a sample placing table;
step 3: imaging an object to be detected by using a structured light camera, establishing a depth map based on an imaging result, converting the depth map into point cloud data, obtaining a point cloud map of the surface of the object to be detected based on the point cloud data, and obtaining normal data of the surface of the object to be detected based on calculation of the point cloud map;
step 4: importing the normal data into a control unit, wherein the control unit establishes a world coordinate system based on the position information of the mobile unit, the position information of the structured light camera and the position information of the object to be detected, and generates a moving track of the mobile unit based on the world coordinate system and the normal data;
step 5: and controlling the mobile unit to move based on the movement track control unit to finish scanning the object to be detected.
CN202310913343.6A 2023-07-24 2023-07-24 Bronze ware detection system and detection method Pending CN116930118A (en)

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CN202310913343.6A CN116930118A (en) 2023-07-24 2023-07-24 Bronze ware detection system and detection method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310913343.6A CN116930118A (en) 2023-07-24 2023-07-24 Bronze ware detection system and detection method

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