CN109357621B - Three-dimensional vibration displacement measuring device and method based on linear array camera and position sensing stripes - Google Patents
Three-dimensional vibration displacement measuring device and method based on linear array camera and position sensing stripes Download PDFInfo
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- CN109357621B CN109357621B CN201811502263.7A CN201811502263A CN109357621B CN 109357621 B CN109357621 B CN 109357621B CN 201811502263 A CN201811502263 A CN 201811502263A CN 109357621 B CN109357621 B CN 109357621B
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- 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
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/03—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring coordinates of points
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
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Abstract
The invention relates to a three-dimensional vibration displacement measuring device and method based on a linear array camera and a position sensing stripe. The device comprises a position sensing stripe, a linear array camera, a data line and a computer. The method comprises the following steps: pasting or spraying a surface-mounted position-sensitive stripe at the measuring position of the vibration structure, and adjusting the imaging position of the linear array camera to enable the center of the position-sensitive stripe to be imaged in the linear array sensor; the position sensing stripe on the surface of the structure vibrates along with the structure, stripe signals imaged in the linear array sensor also change along with the structure, a linear array camera is adopted to continuously image the stripe signals in the vibrating process, and then the acquired stripe sequence is transmitted to a computer through a data line; and finally, processing the stripe sequence by adopting a stripe sequence processing software module, and calculating the three-dimensional vibration displacement information of the structure by using a proposed three-dimensional displacement calculation formula.
Description
Technical Field
The invention relates to the technical field of machine vision measurement vibration, in particular to a three-dimensional vibration displacement measurement device and method based on a linear array camera and position sensing stripes.
Background
The vibration signal of the structure or the equipment has very important significance for the state monitoring and fault diagnosis of the structure and the equipment, and because the dynamic characteristic information of the structure is closely related to the change of the structure parameter, the health state of the structure can be diagnosed by measuring and analyzing the dynamic signal of the structure.
Currently, vibration measurement technologies are mainly classified into contact measurement and non-contact measurement according to whether the vibration measurement technology is in contact with a structure to be measured or not. The contact type vibration measurement method mainly obtains a vibration signal of a structure through a contact type sensor, such as an acceleration sensor, a displacement sensor, a strain gauge and the like. Because the contact measurement methods need to be in contact with a measured structure, the additional mass or the additional external force of the contact measurement methods may affect the measured structure to influence the dynamic characteristics of the structure, thereby affecting the accurate acquisition of the structural modal parameters, which is not suitable for some occasions requiring precise measurement, especially for some light structures. Current non-contact measurement methods include eddy current sensors, laser doppler meters, and the like. The eddy current sensor has requirements on the material of the structure to be measured, the measuring range of the eddy current sensor is generally small, and certain nonlinearity exists in the measuring range, so that the application occasions of the eddy current sensor are limited. Laser doppler meters are expensive and not economical for dynamic measurements of general structures. In addition, the current non-contact measurement methods such as eddy current sensors and laser doppler measurement instruments can only measure vibration in a single dimension, and cannot realize synchronous measurement of multi-dimensional vibration by one sensor or probe.
With the development of image sensor technology and image processing technology, dynamic measurement methods based on machine vision are receiving more and more attention. However, many previous measuring methods only need to use a binocular camera to measure the three-dimensional vibration of the structure, and need to calibrate the spatial coordinates of the camera, so that the actual measuring procedure is complex. There are also some researchers and proposals that use a single two-dimensional image sensor and some specific patterns to enable measurement of three-dimensional dynamic signals of structures. However, this method generally needs to acquire all information of the pattern, the amount of acquired data is large, and methods such as two-dimensional image correlation or image matching are needed to perform image processing to extract displacement information, so the calculation amount is relatively large, and the calculation efficiency and speed are not high.
Therefore, on the basis of understanding and researching the existing three-dimensional vibration measurement method, the invention designs the non-contact three-dimensional vibration displacement measurement device and method based on the linear array camera and the position sensing stripes.
Disclosure of Invention
The invention aims to provide a three-dimensional vibration displacement measuring device and a three-dimensional vibration displacement measuring method based on a linear array camera and position sensing stripes.
In order to achieve the purpose, the technical scheme of the invention is as follows: a three-dimensional vibration displacement measuring device based on linear array camera and position sensing stripes comprises
The one-bit sensing stripe is positioned on the surface of the vibration structure to be detected and used for sensing the three-dimensional space displacement information of the vibration structure to be detected;
the linear array camera is used for carrying out image acquisition and recording on the position sensing stripes on the surface of the tested vibration structure and transmitting acquired stripe sequence signals to the computer through a data line;
the data line is used for communication, control and data transmission between the linear array camera and the computer;
the computer is used for controlling the linear array camera, processing the stripe sequence signal transmitted to the computer in real time and extracting three-dimensional vibration information of the vibration structure to be detected;
and the fringe sequence processing software module is arranged in the computer and used for processing the fringe sequence signal and calculating a three-dimensional vibration signal of the tested vibration structure.
Furthermore, the position sensing stripe is a light patch, one surface of the position sensing stripe facing the linear array camera is a sinusoidal stripe image group, and one surface of the position sensing stripe facing the surface of the vibration structure to be measured is an adhesive layer so as to be adhered to the surface of the vibration structure to be measured; or the position sensing stripe can be directly sprayed on the surface of the vibration structure to be detected, and the surface of the position sensing stripe facing the linear array camera is a sinusoidal stripe image group.
Furthermore, the sinusoidal stripe image group comprises three groups of sinusoidal stripes, the periods of the three groups of sinusoidal stripes are the same, and the stripe density of each group of sinusoidal stripes along the length direction is unchanged; or the sinusoidal stripe image group comprises three groups of sinusoidal stripes, the left group of sinusoidal stripes and the right group of sinusoidal stripes are vertical parallel stripes, and the middle group of sinusoidal stripes and the left group of sinusoidal stripes and the right group of sinusoidal stripes form a preset angle; or the sinusoidal stripe image group comprises three groups of sinusoidal stripes, and the stripe density and the stripe length of the three groups of sinusoidal stripes along the length direction are the same.
Furthermore, when the linear array camera shoots the position-sensitive stripes, the imaging optical axis of the linear array camera is vertical to the plane of the position-sensitive stripes, and the centers of the position-sensitive stripes are imaged on the linear array camera.
Furthermore, each fringe signal in the fringe sequence signals consists of three groups of fringes, convolution operation is carried out on the mother sine fringe signals and the fringe signals, and the center position of each fringe group in the same fringe sequence is determined from the left, middle and right maximum peak coordinates of each group of fringe convolution sequences.
Furthermore, the center distance of the fringe group on the left side and the right side of the fringe signal changes along with the vibration displacement change of the measured vibration structure along the imaging optical axis direction, and the displacement information of the measured vibration structure along the imaging optical axis direction can be obtained through the distance change.
Furthermore, the center distance between the middle stripe group and the left stripe group of the stripe signal changes along with the vibration displacement of the measured vibration structure in the vertical direction, the ratio of the center distance to the center distances of the left and right stripe groups is only related to the displacement in the vertical direction, and the vibration displacement information of the measured vibration structure in the vertical direction can be obtained by solving the ratio of the center distances.
Furthermore, the position of the symmetric center of the stripe groups on the left side and the right side of the stripe signal changes along with the vibration displacement change of the tested vibration structure in the horizontal direction, and the vibration displacement information of the structure in the horizontal direction can be obtained by solving the change of the position of the symmetric center.
Furthermore, the symmetric center position of the left and right stripe groups is determined by the symmetric center coordinate value of the center position coordinate of the left stripe group and the center position coordinate of the right stripe group.
The invention also provides a three-dimensional vibration displacement measurement method based on the linear array camera and the position sensing stripes, which comprises the following steps:
step S1, pasting or spraying a surface-mounted position-sensitive stripe on the surface of the vibration structure to be detected, and adjusting the imaging position of the linear array camera to enable the center of the position-sensitive stripe to be imaged in the linear array sensor of the linear array camera;
step S2, along with the vibration of the vibration structure to be measured, the position sensing stripe on the surface of the vibration structure to be measured also vibrates, the stripe signal imaged in the linear array sensor also changes, and the stripe signal is continuously imaged in the vibration process;
and step S3, transmitting the acquired fringe sequence signals to a computer through a data line, processing the fringe sequence signals by adopting a fringe sequence processing software module, and calculating the three-dimensional vibration information of the structure.
Further, the flow of processing the fringe sequence signal by the fringe sequence processing software module is as follows:
step S11, selecting a first frame stripe signal as a reference frame, calculating the number of pixel points covered by the middle group of stripe signals, and generating mother sine stripes with the same length and the same period number;
step S12, calculating a convolution sequence of the first frame stripe and the mother sine stripe, and obtaining the accurate coordinate position of each maximum peak value of the left, middle and right groups of stripes in the convolution sequence;
step S13, extracting a next frame stripe signal, calculating the density information of the stripes, recalculating the number of pixel points covered by the middle stripes according to the density change information, then regenerating new mother sine stripes, solving the convolution sequence of the current stripe signal and the new mother sine stripes, and finally solving the accurate coordinate position of each maximum peak value of the left, middle and right groups of stripes in the convolution sequence;
step S14, repeating step S13, and calculating the accurate coordinate position of each maximum peak value of the left group of stripes, the middle group of stripes and the right group of stripes of each frame of stripe signal in the convolution sequence;
step S15, calculating the time domain signal of the change of the center distance of the stripe groups at the left and right sides of each frame of stripe signal, and then obtaining the displacement information of the tested vibration structure along the direction of the imaging optical axis;
step S16, calculating a time domain variation curve of the ratio of the distance between the middle stripe and the left stripe center of each frame of stripe signal to the distance between the left stripe center and the right stripe center of each frame of stripe signal, and obtaining vibration displacement information of the tested vibration structure in the vertical direction;
and step S17, calculating time domain signals of the center positions of the stripes on the left side and the right side of each frame of stripe signal, and obtaining vibration displacement information of the tested vibration structure in the horizontal direction.
Further, the displacement mathematical relation of the measured vibration structure along the imaging optical axis direction is as follows:
wherein, Δ x (i) is the displacement of the ith frame of the structure along the direction of the imaging optical axis, D is the imaging object distance between the imaging lens and the position sensing stripe,
and
the center distances of the stripes on the left and right sides of the stripe signal of the ith frame and the reference frame are respectively.
Further, the mathematical relation of the displacement of the measured vibration structure along the vertical direction is as follows:
Δy(i)＝W(Ri-Rr)/(Rmax-Rmin)
wherein, Δ y (i) is the displacement of the ith frame of the structure along the vertical direction, W is the actual width of the position-sensing stripe, RminAnd RmaxThe minimum value and the maximum value of the ratio of the center distance between the middle stripe and the left stripe in the width direction of the position sensing stripe to the center distance between the left stripe and the right stripe in the width direction of the position sensing stripe, RiAnd RrThe ratio of the distance between the center of the middle stripe and the left stripe of the stripe signal of the ith frame and the reference frame and the distance between the centers of the left stripe and the right stripe is respectively.
Further, the displacement of the measured vibration structure along the horizontal direction is mathematically expressed as:
wherein, Δ z (i) is the displacement of the ith frame of the structure along the horizontal direction, L is the actual distance between the centers of the left and right stripes of the position sensing stripe, N is the number of pixel points covered in the distance between the centers of the left and right stripes of the stripe signal of the reference frame,
and
the coordinates of the symmetric center positions of the stripes on the left side and the right side of the stripe signal of the ith frame and the reference frame are respectively.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention only needs one single-position sensing stripe as a sensor, one linear array camera as a detector can sense the three-dimensional vibration information of the structure, and one sensor does not need to be arranged in each vibration direction like a single-dimensional sensor;
(2) the bit-sensitive stripe has low cost, almost no additional mass is introduced, no additional mass is introduced to the structure, and the modal parameters of the structure are not changed;
(3) the invention can realize the measurement of the three-dimensional vibration of the structure by adopting the linear array sensor, and has more cost saving and higher measurement efficiency compared with a monocular or binocular vision three-dimensional vibration measurement method based on an area array sensor.
Drawings
Fig. 1 is a schematic structural diagram of an apparatus according to an embodiment of the present invention and fig. 1.
FIG. 2 is a flow chart illustrating stripe design and stripe sequence processing according to an embodiment of the present invention; wherein, FIG. 2(a) is a proposed bit-sensitive stripe design; FIG. 2(b) is a central position curve of the left, middle and right groups of stripes in FIG. 2 (a); FIG. 2(c) is a fringe intensity curve at the dashed line in FIG. 2 (a); FIG. 2(d) is a convolution sequence intensity curve of the stripe intensity curve and the parent sinusoidal stripe in FIG. 2 (c).
Fig. 3 is a schematic diagram of bit-induced fringe imaging according to an embodiment of the present invention.
In the figure, 1-position sensing stripe, 2-vibration structure, 3-linear array camera, 4-data line, 5-computer, 31-linear array sensor and 32-imaging lens.
Detailed Description
The technical scheme of the invention is specifically explained below with reference to the accompanying drawings.
The invention provides a three-dimensional vibration displacement measuring device based on a linear array camera and position sensing stripes, which comprises
The one-bit sensing stripe is positioned on the surface of the vibration structure to be detected and used for sensing the three-dimensional space displacement information of the vibration structure to be detected;
the linear array camera is used for carrying out image acquisition and recording on the position sensing stripes on the surface of the tested vibration structure and transmitting acquired stripe sequence signals to the computer through a data line;
the data line is used for communication, control and data transmission between the linear array camera and the computer;
the computer is used for controlling the linear array camera, processing the stripe sequence signal transmitted to the computer in real time and extracting three-dimensional vibration information of the vibration structure to be detected;
and the fringe sequence processing software module is arranged in the computer and used for processing the fringe sequence signal and calculating a three-dimensional vibration signal of the tested vibration structure.
The invention also provides a three-dimensional vibration displacement measurement method based on the linear array camera and the position sensing stripes, which comprises the following steps:
step S1, pasting or spraying a surface-mounted position-sensitive stripe on the surface of the vibration structure to be detected, and adjusting the imaging position of the linear array camera to enable the center of the position-sensitive stripe to be imaged in the linear array sensor of the linear array camera;
step S2, along with the vibration of the vibration structure to be measured, the position sensing stripe on the surface of the vibration structure to be measured also vibrates, the stripe signal imaged in the linear array sensor also changes, and the stripe signal is continuously imaged in the vibration process;
and step S3, transmitting the acquired fringe sequence signals to a computer through a data line, processing the fringe sequence signals by adopting a fringe sequence processing software module, and calculating the three-dimensional vibration information of the structure.
The following is a specific implementation of the present invention.
Fig. 1 is a schematic structural diagram of an apparatus according to an embodiment of the present invention. As shown in fig. 1, the present embodiment provides a structure three-dimensional vibration displacement measurement apparatus based on a line camera and a position-sensitive stripe, which includes a position-sensitive stripe 1, a vibration structure 2, a line camera 3, a data line 4, and a computer 5. The position-sensing stripe 1 is adhered or sprayed on the surface of the vibrating structure 2 to sense the three-dimensional space displacement information of the vibrating structure 2. The linear array camera 3 is used for carrying out image acquisition and recording on the position sensing stripe 1 on the surface of the vibrating structure 2, and transmitting an acquired stripe signal sequence to the computer 5 through the data line 4 for storage and processing. The computer 5 is used for controlling the start and stop of the linear array camera and parameter setting, and a stripe sequence processing software module is installed in the computer 5 and can process the stripe sequence transmitted to the computer in real time to extract a time domain three-dimensional vibration signal of the structure.
FIG. 2 is a flow chart illustrating the stripe design and stripe sequence processing according to an embodiment of the present invention. As shown in fig. 2, fig. 2(a) is a design diagram of the bit-sensing stripe proposed in this embodiment. The position sensing stripes 1 are composed of three groups of sine stripes, the left group of sine stripes and the right group of sine stripes are vertical parallel stripes, the middle group of sine stripes and the left group of sine stripes and the right group of sine stripes form a certain angle, and the stripe density and the stripe length of the three groups of sine stripes along the length direction are the same. The graph (b) is a central position curve of the left, middle and right groups of stripes in the graph (a), when the position sensing stripes have displacement delta Y in the vertical direction (Y direction), the central position distance L between the middle stripe and the left stripe isclThe distance L from the center of the left and right stripesrlThe ratio between the two signals is changed, and the displacement signal of the vibrating structure 2 in the vertical direction can be obtained through the change of the ratio. The mathematical relationship of the displacement of the vibrating structure 2 along the vertical direction is:
Δy(i)＝W(Ri-Rr)/(Rmax-Rmin)
wherein Δ y (i) is the displacement of the ith frame of the structure along the vertical direction, W is the actual width of the position-sensing stripe, RminAnd RmaxThe minimum value and the maximum value of the ratio of the center distance between the middle stripe and the left stripe in the width direction of the position sensing stripe to the center distance between the left stripe and the right stripe in the width direction of the position sensing stripe, RiAnd RrThe ratio of the distance between the center of the middle stripe and the left stripe of the stripe signal of the ith frame and the reference frame and the distance between the centers of the left stripe and the right stripe is respectively.
The key to this three-dimensional displacement measurement is to obtainInformation on the center position between the respective sets of the bit-sensitive stripes 1, and (c) is a stripe intensity curve at the dotted line in the graph (a). To obtain the center position information of each stripe group, the embodiment proposes to perform convolution operation by using the mother sine stripe and the acquired stripe signal, and determine the center position coordinates of the stripes by the maximum peak positions at the left, middle and right positions of the convolution sequence. (d) Is the convolved sequence intensity curve of the stripe intensity curve with the parent sinusoidal stripe in graph (c), where Pl、Pc、PrThe coordinates of the center positions of the obtained left, middle and right stripe groups are respectively.
Fig. 3 is a schematic diagram of bit-induced fringe imaging according to an embodiment of the present invention. As shown in fig. 3, the imaging optical axis of the line camera 3 is perpendicular to the plane of the bit-sensitive stripe 1, and the line camera 3 can only image a stripe group at a certain row position of the bit-sensitive stripe 1 at a time. When the vibrating structure 2 has a displacement Δ X along the imaging optical axis direction (X direction), the central distance of the left and right parallel stripe groups of the position sensing stripe 1 will change in the linear array sensor 31, and the displacement measurement of the vibrating structure 2 along the optical axis direction can be realized through the change, and the mathematical relationship of the displacement calculation is as follows:
where Δ x (i) is the displacement of the ith frame of the structure along the imaging optical axis direction, D is the imaging object distance between the imaging lens 32 and the bit-sensitive stripe 1,
and
the center distances of the stripes on the left and right sides of the stripe signal of the ith frame and the reference frame are respectively. Wherein L isrlThe mathematical formula of (2) is:
Lrl＝Pr-Pl
when the vibrating structure 2 has a displacement Δ Z along the horizontal direction (Z direction), the position of the symmetric center of the left and right stripes of the position sensing stripe signal will change, and the vibration displacement information of the vibrating structure 2 in the horizontal direction can be obtained by solving the change of the position of the symmetric center. The displacement of the structure along the horizontal direction is mathematically expressed as:
wherein, Δ z (i) is the displacement of the ith frame of the structure along the horizontal direction, L is the actual distance between the centers of the left and right stripes of the position sensing stripe, N is the number of pixel points covered in the distance between the centers of the left and right stripes of the stripe signal of the reference frame,
and
coordinates of symmetric center positions of stripes on the left side and the right side of the stripe signal of the ith frame and the reference frame respectively have a value calculation formula as follows:
the above are preferred embodiments of the present invention, and all changes made according to the technical scheme of the present invention that produce functional effects do not exceed the scope of the technical scheme of the present invention belong to the protection scope of the present invention.
Claims (7)
1. A three-dimensional vibration displacement measuring device based on linear array camera and position sensing stripe is characterized by comprising
The one-bit sensing stripe is positioned on the surface of the vibration structure to be detected and used for sensing the three-dimensional space displacement information of the vibration structure to be detected;
the linear array camera is used for carrying out image acquisition and recording on the position sensing stripes on the surface of the tested vibration structure and transmitting acquired stripe sequence signals to the computer through a data line;
the data line is used for communication, control and data transmission between the linear array camera and the computer;
the computer is used for controlling the linear array camera, processing the stripe sequence signal transmitted to the computer in real time and extracting three-dimensional vibration information of the vibration structure to be detected;
the fringe sequence processing software module is arranged in the computer and used for processing the fringe sequence signal and calculating a three-dimensional vibration signal of the tested vibration structure;
each fringe signal in the fringe sequence signals consists of three groups of fringes, convolution operation is carried out on the mother sine fringe signals and the fringe signals, and the central position of each fringe group in the same fringe sequence is determined from the left, middle and right maximum peak coordinates of each group of fringe convolution sequences;
the central distance of the fringe group at the left side and the right side of the fringe signal changes along with the vibration displacement change of the tested vibration structure along the direction of the imaging optical axis, and the displacement information of the tested vibration structure along the direction of the imaging optical axis can be obtained through the distance change; the central distance between the middle stripe group and the left stripe group of the stripe signal changes along with the vibration displacement of the measured vibration structure in the vertical direction, the ratio of the central distance to the central distances of the left and right stripe groups is only related to the displacement in the vertical direction, and the vibration displacement information of the measured vibration structure in the vertical direction can be obtained by solving the ratio of the central distances; the position of the symmetric center of the stripe groups on the left side and the right side of the stripe signal changes along with the vibration displacement change of the tested vibration structure in the horizontal direction, and the vibration displacement information of the tested vibration structure in the horizontal direction can be obtained by solving the change of the position of the symmetric center; the symmetric center position of the left and right stripe groups is determined by the symmetric center coordinate value of the center position coordinate of the left stripe group and the center position coordinate of the right stripe group.
2. The three-dimensional vibration displacement measuring device based on the line camera and the position-sensing stripes as claimed in claim 1, wherein the position-sensing stripes are light patches, one surface of each light patch facing the line camera is a sinusoidal stripe image group, and one surface of each light patch facing the surface of the vibration structure to be measured is an adhesive layer so as to be adhered to the surface of the vibration structure to be measured; or the position sensing stripe can be directly sprayed on the surface of the tested vibration structure, and the surface of the position sensing stripe facing the linear array camera is a sinusoidal stripe image group; the sinusoidal stripe image group comprises three groups of sinusoidal stripes, the periods of the three groups of sinusoidal stripes are the same, and the stripe density of each group of sinusoidal stripes along the length direction is unchanged; or the sinusoidal stripe image group comprises three groups of sinusoidal stripes, the left group of sinusoidal stripes and the right group of sinusoidal stripes are vertical parallel stripes, and the middle group of sinusoidal stripes and the left group of sinusoidal stripes and the right group of sinusoidal stripes form a preset angle; or the sinusoidal stripe image group comprises three groups of sinusoidal stripes, and the stripe density and the stripe length of the three groups of sinusoidal stripes along the length direction are the same.
3. The linear array camera and displacement stripe-based three-dimensional vibration displacement measurement device according to claim 1, wherein an imaging optical axis of the linear array camera is perpendicular to a plane of the displacement stripe when the linear array camera shoots the displacement stripe, and a center of the displacement stripe is imaged on the linear array camera.
4. A three-dimensional vibration displacement measurement method based on a linear array camera and a position sensing stripe is characterized by comprising the following steps:
step S1, pasting or spraying a surface-mounted position-sensitive stripe on the surface of the vibration structure to be detected, and adjusting the imaging position of the linear array camera to enable the center of the position-sensitive stripe to be imaged in the linear array sensor of the linear array camera;
step S2, along with the vibration of the vibration structure to be measured, the position sensing stripe on the surface of the vibration structure to be measured also vibrates, the stripe signal imaged in the linear array sensor also changes, and the stripe signal is continuously imaged in the vibration process;
step S3, transmitting the acquired fringe sequence signal to a computer through a data line, processing the fringe sequence signal by adopting a fringe sequence processing software module, and calculating three-dimensional vibration information of the structure;
the flow of the stripe sequence processing software module for processing the stripe sequence signal is as follows:
step S11, selecting a first frame stripe signal as a reference frame, calculating the number of pixel points covered by the middle group of stripe signals, and generating mother sine stripes with the same length and the same period number;
step S12, calculating a convolution sequence of the first frame stripe and the mother sine stripe, and obtaining the accurate coordinate position of each maximum peak value of the left, middle and right groups of stripes in the convolution sequence;
step S13, extracting a next frame stripe signal, calculating the density information of the stripes, recalculating the number of pixel points covered by the middle stripes according to the density change information, then regenerating new mother sine stripes, solving the convolution sequence of the current stripe signal and the new mother sine stripes, and finally solving the accurate coordinate position of each maximum peak value of the left, middle and right groups of stripes in the convolution sequence;
step S14, repeating step S13, and calculating the accurate coordinate position of each maximum peak value of the left group of stripes, the middle group of stripes and the right group of stripes of each frame of stripe signal in the convolution sequence;
step S15, calculating the time domain signal of the change of the center distance of the stripe groups at the left and right sides of each frame of stripe signal, and then obtaining the displacement information of the tested vibration structure along the direction of the imaging optical axis;
step S16, calculating a time domain variation curve of the ratio of the distance between the middle stripe and the left stripe center of each frame of stripe signal to the distance between the left stripe center and the right stripe center of each frame of stripe signal, and obtaining vibration displacement information of the tested vibration structure in the vertical direction;
and step S17, calculating time domain signals of the center positions of the stripes on the left side and the right side of each frame of stripe signal, and obtaining vibration displacement information of the tested vibration structure in the horizontal direction.
5. The three-dimensional vibration displacement measurement method based on the line camera and the position sensing stripes as recited in claim 4, wherein the mathematical relationship of the displacement of the measured vibration structure along the direction of the imaging optical axis is as follows:
wherein, Δ x (i) is the displacement of the ith frame of the structure along the direction of the imaging optical axis, D is the imaging object distance between the imaging lens and the position sensing stripe,
and
the center distances of the stripes on the left and right sides of the stripe signal of the ith frame and the reference frame are respectively.
6. The three-dimensional vibration displacement measurement method based on the line camera and the position sensing stripes as recited in claim 4, wherein the mathematical relationship of the displacement of the measured vibration structure along the vertical direction is as follows:
Δy(i)＝W(Ri-Rr)/(Rmax-Rmin)
wherein, Δ y (i) is the displacement of the ith frame of the structure along the vertical direction, W is the actual width of the position-sensing stripe, RminAnd RmaxThe minimum value and the maximum value of the ratio of the center distance between the middle stripe and the left stripe in the width direction of the position sensing stripe to the center distance between the left stripe and the right stripe in the width direction of the position sensing stripe, RiAnd RrThe ratio of the distance between the center of the middle stripe and the left stripe of the stripe signal of the ith frame and the reference frame and the distance between the centers of the left stripe and the right stripe is respectively.
7. The three-dimensional vibration displacement measurement method based on the line camera and the position sensing stripes as recited in claim 4, wherein the mathematical relationship of the displacement of the measured vibration structure along the horizontal direction is as follows:
wherein, Δ z (i) is the displacement of the ith frame of the structure along the horizontal direction, L is the actual distance between the centers of the left and right stripes of the position sensing stripe, N is the number of pixel points covered in the distance between the centers of the left and right stripes of the stripe signal of the reference frame,
and
the coordinates of the symmetric center positions of the stripes on the left side and the right side of the stripe signal of the ith frame and the reference frame are respectively.
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| CN112683382B (en) * | 2020-12-31 | 2022-05-13 | 福州大学 | Structure three-dimensional vibration measurement system and method based on monocular vision |
| CN112697259B (en) * | 2020-12-31 | 2022-04-08 | 福州大学 | Beam structure modal shape measuring device and method based on combined stripes |
| CN112763501A (en) * | 2021-01-22 | 2021-05-07 | 福州大学 | Rotating shaft fault detection system and method based on visual measurement |
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