CN115574725A - Steel plate size measuring method and system based on line structured light - Google Patents
Steel plate size measuring method and system based on line structured light Download PDFInfo
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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
- G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates
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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
- G01B11/022—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by means of tv-camera scanning
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Abstract
The application provides a method and a system for measuring the size of a steel plate based on line structured light, wherein the method for measuring the size of the steel plate comprises the following steps: acquiring the inclination angle and the plate head of a steel plate to be detected; adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be measured; moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the tail of the steel plate to be detected, marking a first time when the linear structured light scans to the head of the steel plate, and marking a second time when the linear structured light scans to the tail of the steel plate; acquiring a scanning image group of a steel plate to be detected; the scanning image group comprises each frame image in the line structured light scanning process; extracting the width of the steel plate to be detected from the scanning image group; and determining the length of the steel plate to be measured according to the preset speed, the first time and the second time. Therefore, the length and the width of the steel plate to be measured can be accurately measured according to the central line by scanning the steel plate to be measured with the reinforced line structure light and then extracting the central line of the line structure light.
Description
Technical Field
The application relates to the field of steel plate production, in particular to a method and a system for measuring the size of a steel plate based on line structured light.
Background
The steel plate is an important product produced by a plate coil factory according to a preset size, and the size of the produced steel plate needs to be measured for ensuring the quality.
Coil mills typically use manual methods for dimensional measurements. Referring to fig. 1, a schematic diagram of the prior art steel plate dimension measurement is shown. As can be seen from fig. 1, the prior art requires two operators to stand at both ends of the steel sheet to be measured and tension the tape measure to make the measurement. However, the steel plate has slight jitter and position inclination during measurement, which may cause inaccurate measurement results, wherein the slight jitter may cause a large difference between values measured before and after the measurement, and the position inclination may cause the measured side length of the steel plate to be smaller than the actual side length.
At present, line structured light is increasingly used for dimensional measurement, however, line structured light is generally used for measuring local dimensions of small parts. For steel plates, especially for medium-thickness steel plates, a stronger light intensity and a longer linear light strip are often required. Therefore, the conventional line structured light cannot measure the size of the steel plate.
Disclosure of Invention
The application provides a method and a system for measuring the size of a steel plate based on line structured light, which can be used for solving the technical problem that the size of the steel plate cannot be measured by the existing line structured light.
In a first aspect, the present application provides a method for measuring a dimension of a steel plate based on line structured light, including:
acquiring the inclination angle and the plate head of a steel plate to be detected;
adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected;
moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the plate tail of the steel plate to be detected, marking a first time when the linear structured light scans to the plate head, and marking a second time when the linear structured light scans to the plate tail; the linear structured light moves from the initial scanning position to the head of the plate until the tail of the plate is scanned and stops;
acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line-structured light scanning process;
extracting the width of the steel plate to be detected from the scanning image group;
and determining the length of the steel plate to be tested according to the preset speed, the first time and the second time.
In an implementation manner of the first aspect, before the obtaining the inclination angle and the plate head of the steel plate to be measured, the method for measuring the size of the steel plate further includes:
detecting whether an in-place signal is sent out; the in-place signal is used for indicating that the steel plate to be measured reaches a measuring station;
if the in-place signal is sent out, executing the step to obtain the inclination angle and the plate head of the steel plate to be detected;
and if the in-place signal is not sent out, continuing to wait for the in-place signal.
In one implementation manner of the first aspect, the adjusting the line structured light to the initial scanning position according to the tilt angle and the plate head includes:
adjusting the line structured light to be parallel to the edge of the board head according to the inclination angle and the board head;
translating the line structure light to the initial scanning position.
In an implementation manner of the first aspect, the extracting the width of the steel plate to be detected from the scanning image group includes:
extracting the central line of the line structured light from each frame of image;
calibrating the central line, and acquiring the width of the steel plate in each frame of image;
removing abnormal values of the width of the steel plate in all the images, and acquiring a mode of the residual width;
and determining the mode as the width of the steel plate to be measured.
In one implementation manner of the first aspect, the extracting a center line of the line-structured light from each frame of the image includes:
the center line of line structured light is extracted from each frame of image according to the following formula:
wherein ,f（x，y) Is a line-structured light stripe image (x，y) The gray-scale value of (a) is,Ta threshold value for the extraction of the fringes,g（u，v) Is extracted fromu，v) A gray value of (b) andu＝x－w 0 ，v＝y－h 0 ，w 0 for the number of offset columns in the image,h 0 the number of offset lines in the image;
optimizing the centerline according to the formula:
wherein ,g（u，v) In order to preliminarily extract the stripe region,h（i，j) To optimize the fringe area (i，j) At a gray value of (b), andi=u-w 1 ，j=v-h 1 ，w 1 ，h 1 respectively, the number of columns and rows of fringe fields offset.
In an implementation manner of the first aspect, the calibrating the center line and obtaining a width of the steel plate in each frame of image includes:
calibrating camera parameters according to the following formula:
calibrating the plane parameters of the line structured light according to the following formula:
wherein ,（x i ，y i ，z i ) Coordinates of the stripes on the checkerboard under the camera coordinate system are calibrated,nfor the number of stripe points that are not on a straight line.
In an implementation manner of the first aspect, the obtaining a mode of a remaining width after removing the abnormal values of the steel plate widths in all the images includes:
the mode of the residual width is obtained according to the following formula:
wherein ,（u，v) Is the center line: (a)X c ,Y c ,Z c ) Is the only spatial point corresponding to a point on the image in the camera coordinate system.
In an implementation manner of the first aspect, the determining the length of the steel plate to be measured according to the preset speed, the first time, and the second time includes:
determining the length of the steel plate to be measured according to the following formula:
wherein ,Lis the length of the steel plate to be measured,Vto the preset speed，t 0 As the first time, the time is the first time,t 1 is the second time.
In a second aspect, the present application provides a steel plate dimension measuring system based on line structured light, where the steel plate dimension measuring system is configured to perform a steel plate dimension measuring method based on line structured light in the first aspect and in various implementations, and the steel plate dimension measuring system includes:
the actuating mechanism module comprises a servo motor unit, a switch and a trigger signal unit and is used for controlling the starting and the closing of the steel plate dimension measuring system;
the object in-place detection module is used for executing the following steps:
before the inclination angle and the plate head of the steel plate to be detected are obtained, whether an in-place signal is sent out is detected;
a structured light width measurement module for performing the steps of:
acquiring the inclination angle and the plate head of a steel plate to be detected;
adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected;
moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the plate tail of the steel plate to be detected, marking a first time when the linear structured light scans to the plate head, and marking a second time when the linear structured light scans to the plate tail; the linear structured light moves from the initial scanning position to the head of the plate until the tail of the plate is scanned and stops;
acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line structured light scanning process;
extracting the width of the steel plate to be detected from the scanning image group;
the structured light length measuring module is used for executing the following steps:
and determining the length of the steel plate to be measured according to the preset speed, the first time and the second time.
In one implementation manner of the second aspect, the steel plate dimension measuring system further includes a hardware structure, and the hardware structure includes:
the measuring device comprises a moving guide roller and a measuring device arranged on the moving guide roller; the measuring device can move along the moving guide roller;
the measuring device includes:
the industrial camera is provided with a lens, and the lens is used for acquiring the scanning image group;
a line-structured light emitter for emitting line-structured light;
and the heat insulation and dissipation device is arranged at the tail ends of the industrial camera and the line-structured light emitter and is used for keeping the temperature balance of the industrial camera and the line-structured light emitter.
According to the technical scheme, the steel plate dimension measuring method and system based on line structured light comprise the following steps: acquiring the inclination angle and the plate head of a steel plate to be detected; adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected; moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the plate tail of the steel plate to be detected, marking a first time when the linear structured light scans to the plate head, and marking a second time when the linear structured light scans to the plate tail; the linear structured light moves from the initial scanning position to the head of the plate until the tail of the plate is scanned and stops; acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line structured light scanning process; extracting the width of the steel plate to be detected from the scanning image group; and determining the length of the steel plate to be tested according to the preset speed, the first time and the second time.
Therefore, the length and the width of the steel plate to be detected are accurately measured according to the central line by scanning the steel plate to be detected with the reinforced line structure light and extracting the central line of the line structure light.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without any creative effort.
FIG. 1 is a schematic diagram of the measurement of the dimension of a steel plate in the prior art;
FIG. 2 is a schematic view of the line structured light measurement principle;
fig. 3 is a schematic diagram of a hardware structure of a steel plate dimension measuring system of a steel plate dimension measuring method based on line structured light according to the present application;
fig. 4 is a schematic flow chart of a method for measuring the size of a steel plate based on line structured light provided by the present application;
fig. 5 is a schematic diagram illustrating centerline extraction of line structured light in the steel plate dimension measurement method based on line structured light provided in the present application.
In fig. 3:
the device comprises a moving guide roller 1, a measuring device 2, an industrial camera 21, a lens 22, a linear structure light emitter 23, a heat insulation and heat dissipation device 24, a portal frame 3 and a steel plate to be measured 4.
Detailed Description
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of this application and the appended claims, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, such as "one or more", unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of the present application, "at least one," one or more "means one, two or more," and "a plurality" means two or more. The term "and/or" is used to describe the association relationship of the associated objects, and means that there may be three relationships; for example, a and/or B, may represent: a exists singly, A and B exist simultaneously, and B exists singly, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.
First, the line structured light measurement principle applied in the embodiment of the present application is described below:
fig. 2 is a schematic view of the line structured light measurement principle;
as can be seen from fig. 2, the line-structured light emitted from the line-structured light emitter is converged and irradiated on the surface of the object to be measured, and then the scattered light is received by the lens and converged on the linear photoelectric element imaging chip. When the surface of the object to be measured is displaced, the object light point deviates from the original object surface point, and the image light point also correspondingly generates a phase shift. For a rectangular steel plate, the image light spots are connected into light bars, and the size of the object is measured according to the change of the light bars.
The hardware structure for implementing the steel plate size measuring method of the present application is described as follows:
referring to fig. 3, a hardware structure diagram of a steel plate dimension measuring system of the steel plate dimension measuring method based on line structured light is provided in the present application.
As can be seen from fig. 3, the hardware structure of the steel plate dimension measuring system includes:
the device comprises a moving guide roller 1 and a measuring device 2 arranged on the moving guide roller 1; the measuring device 2 can move along the moving guide roller 1;
the measuring device 2 includes:
an industrial camera 21, wherein a lens 22 is disposed on the industrial camera 21, and the lens 22 is used for acquiring the scanning image group;
a line-structured light emitter 23 for emitting line-structured light;
a heat insulation and dissipation device 24 disposed at the rear ends of the industrial camera and the line-structured light emitter for keeping the temperature balance of the industrial camera and the line-structured light emitter;
in the actual use process, all the hardware structures can be arranged on the portal frame 3 and above the steel plate 4 to be measured.
The first embodiment of the present application discloses a method for measuring a dimension of a steel plate based on line structured light, and the following description specifically describes the method for measuring a dimension of a steel plate based on line structured light disclosed in the first embodiment of the present application with reference to the accompanying drawings.
Referring to fig. 4, a schematic flow chart of a method for measuring the size of a steel plate based on line structured light provided by the present application is shown;
as shown in fig. 4, a method for measuring a dimension of a steel plate based on line structured light according to a first embodiment of the present application includes:
in this embodiment, the obtaining of the inclination angle and the board head is completed by the industrial camera 21, and the industrial camera 21 performs shooting, visually detects the inclination angle and the position of the board head, and sends an angle signal to a PLC (Programmable Logic Controller).
in this embodiment of the present application, the step 102 includes:
step 201, adjusting the line structured light to be parallel to the edge of the board head according to the inclination angle and the board head;
step 202, translating the line structure light to the initial scanning position.
In the embodiment of the present application, the PLC adjusts the scanning angle of the linear structured light emitter 23 above the gantry 3 to be parallel to the edge line of the plate head of the steel plate to be measured.
103, moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the tail of the steel plate to be detected, and marking a first time when the linear structured light scans to the head of the steel plate and a second time when the linear structured light scans to the tail of the steel plate; the direction of the linear structure light movement is from the initial scanning position to the board head until the scanning is stopped at the board tail.
In this embodiment of the present application, after the visually detected position of the board head is sent to the PLC, the PLC moves the linear structured light emitter 23 to the initial scanning position, so as to ensure that the board head is kept in a uniform velocity state when being scanned, and the velocity of the uniform velocity motion is preset. In order to ensure the uniform speed, the moving speed of the conveyor belt needs to be sent to the system at regular time, and the system records the first time when the light of the linear structure falls on the edge line of the plate headt 0 And the second time when the line structure light falls on the board tail edge linet 1 。
104, acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line structured light scanning process.
105, extracting the width of the steel plate to be detected from the scanning image group;
in the embodiment of the present application, in step 105, the industrial camera 21 records each frame of image in real time according to the line structured light measurement principle. The center line of the line structured light is extracted from each frame image and its length Width _ pixel is calculated. And calibrating the central line, and converting the central line into the Width _ real of the steel plate. And eliminating abnormal values and calculating the mode of the Width _ real of each frame of image to obtain the Width of the slab.
Specifically, the step 105 includes:
step 502, extracting the central line of the line structured light from each frame of image;
in the embodiment of the application, a threshold segmentation method is firstly adopted to preliminarily extract a fringe region from a fringe image, the fringe region is further optimized by combining a maximum value method, and then the center point of the fringe region is extracted by a Hessian matrix method.
Referring to fig. 5, a schematic diagram of extracting a center line of line structured light in the method for measuring the size of a steel plate based on line structured light provided by the present application is shown;
as can be seen from fig. 5, since the line structured light is relatively thick light and an error is caused by directly using the line structured light, a central line of the line structured light needs to be extracted and is relatively thin, so that an error caused by a width of the line structured light is avoided. Thus, said step 502 comprises:
step 5021, extracting the central line of the line structured light from each frame of image comprises:
step 5022, the central line of the line structured light is extracted from each frame of image according to the following formula:
wherein ,f（x，y) Is a line-structured light stripe image (x，y) The gray-scale value of (a) is,Ta threshold value for the extraction of the fringes,g（u，v) Is extracted fromu，v) At a gray value of (b), andu＝x－w 0 ，v＝y－h 0 ，w 0 for the number of offset columns in the image,h 0 the number of offset lines in the image;
in the embodiment of the present application, the industrial camera 21 is a camera with a filter, and in the acquired image, the gray value of the stripe portion is significantly greater than that of other portions, so a threshold segmentation method is adopted to extract the stripe region of the image, as shown in formula (1).
Step 5023, optimizing the center line according to the following formula:
wherein ,g（u，v) In order to preliminarily extract the stripe region,h（i，j) For optimizing stripe region: (i，j) At a gray value of (b), andi=u-w 1 ，j=v-h 1 ，w 1 ，h 1 the number of columns and rows, respectively, of the stripe region offsets.
In the embodiment of the present application, due to the characteristics of the line structured light, the gray level values of the ideal stripe regions should be in gaussian distribution, but the extracted gray level values of the stripe regions are abnormal due to the external illumination influence and the influence of different surface reflectivities of the workpiece. In order to reduce the influence of abnormal values, a maximum value method is adopted to search the maximum value of the gray scale of the fringe area, and tau pixels are selected near the coordinate of the maximum value of the gray scale to optimize the fringe area, as shown in formula (2).
Step 503, calibrating the center line, and acquiring the width of the steel plate in each frame of image;
in the embodiment of the present application, since the camera parameter calibration can only obtain a ray passing through the optical center of the line structure, in order to obtain the position of the line structure light on the surface of the workpiece in the camera coordinate system, the camera parameter calibration is performed, and the line structure light plane parameter calibration is performed, so that the points in the camera coordinate system are converted into the points in the line structure light coordinate system.
Specifically, in this embodiment, the step 503 includes:
step 5031, calibrating camera parameters according to the following formula:
in the embodiment of the application, a chequer-based Zhang-Zheng-friend calibration method is adopted to calibrate the camera so as to acquire optical parameters of the camera and external parameters relative to a world coordinate system. That is, the camera calibration parameters are solved by establishing the corresponding relationship between the positions of the corner points on the checkerboard calibration board and the coordinates of the corner points on the image plane, as shown in formula (3).
Step 5032, calibrating the plane parameter of the line structured light according to the following formula:
wherein ,（x i ，y i ，z i ) Coordinates of the stripes on the checkerboard under the camera coordinate system are calibrated,nfor the number of stripe points that are not on a straight line.
In the embodiment of the present application, it can be known from the principle of triangulation that the three-dimensional coordinates of the surface stripes of the workpiece are required to be obtained, and besides calibrating the camera parameters, the linear structured light plane method is also required to be calibrated. The method adopts a least square method to calibrate the plane parameters of the linear structured light, as shown in a formula (4).
Step 504, eliminating abnormal values of the steel plate width in all the images, and acquiring a mode of the residual width;
in the embodiment of the application, the length Width _ pixel of the line laser pixel is converted into the Width _ real of the steel plate according to the calibrated vision system. The specific method comprises the following steps: and calculating the corresponding unique spatial point relation of the points on the image under the camera coordinate system by combining the camera calibration parameter equation and the linear structure light plane parameter equation. Then, all the images are added into a queue buffer mechanism, abnormal values are eliminated through the real-time calculation of the Width _ real of each frame of image, and a more stable mode is used as the Width of the bit slab.
Specifically, the step 504 includes:
the mode of the residual width is obtained according to the following formula:
wherein ,（u，v) Is the center line (a)X c ,Y c ,Z c ) Is the only spatial point corresponding to a point on the image under the camera coordinate system.
In the embodiment of the present application, the centerline is extracted by the above-mentioned line-structured striation center extraction algorithm(s) ((u，v) Calculating a unique spatial point corresponding to the point on the image under the camera coordinate system according to the formula (3) and the formula (4) ((X c ,Y c ,Z c ) As shown in equation (5).
And 505, determining the mode as the width of the steel plate to be measured.
And 106, determining the length of the steel plate to be measured according to the preset speed, the first time and the second time.
The step 106 includes:
determining the length of the steel plate to be measured according to the following formula:
wherein ,Lis the length of the steel plate to be measured,Vin order to be said preset speed, the speed of the motor is set,t 0 as the first time is a time of day,t 1 is the second time.
In the embodiment of the application, when line structured light scans the edge line of the tail of the board, the frame is identified, and the current time point is recordedt 1 。
In order to enable the measured length to be more accurate, real-time speed information sent by the PLC is stored in a queue, data processing is carried out, abnormal values of average speeds are eliminated, and the multiplicity of all the average speeds is calculatedV Fruit of Chinese wolfberry . Using actual average speed of movement V of the mobile device Fruit of Chinese wolfberry And line structured light scan object time (t 1 -t 0 ) The length of the medium plate is calculated as shown in (7)L。
L=(t 1 -t 0 )×V Fruit of Chinese wolfberry （7）
wherein ,Lis the length of the steel plate to be measured,V fruit of Chinese wolfberry Is the actual average speed of movement as described,t 0 as the first time is a time of day,t 1 is the second time.
According to the technical scheme, the application provides a method and a system for measuring the size of a steel plate based on line structured light, and the method for measuring the size of the steel plate comprises the following steps: acquiring the inclination angle and the plate head of a steel plate to be detected; adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected; moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the plate tail of the steel plate to be detected, marking a first time when the linear structured light scans to the plate head, and marking a second time when the linear structured light scans to the plate tail; the linear structure light moves from the initial scanning position to the head until the tail of the board is scanned and stops; acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line-structured light scanning process; extracting the width of the steel plate to be detected from the scanning image group; and determining the length of the steel plate to be measured according to the preset speed, the first time and the second time.
Therefore, the length and the width of the steel plate to be detected are accurately measured according to the central line by scanning the steel plate to be detected with the reinforced line structure light and extracting the central line of the line structure light.
Corresponding to a method for measuring a dimension of a steel plate based on line structured light provided in a first embodiment of the present application, a second embodiment of the present application provides a system for measuring a dimension of a steel plate based on line structured light, the system comprising:
the actuating mechanism module comprises a servo motor unit, a switch and a trigger signal unit and is used for controlling the starting and the closing of the steel plate size measuring system;
the object in-place detection module is used for executing the following steps:
before the inclination angle and the plate head of the steel plate to be detected are obtained, whether an in-place signal is sent out is detected;
a structured light width measurement module for performing the steps of:
acquiring the inclination angle and the plate head of a steel plate to be detected;
adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected;
moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the tail of the steel plate to be detected, and marking a first time when the linear structured light scans to the head of the steel plate and a second time when the linear structured light scans to the tail of the steel plate; the linear structured light moves from the initial scanning position to the head of the plate until the tail of the plate is scanned and stops;
acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line structured light scanning process;
extracting the width of the steel plate to be detected from the scanning image group;
the structured light length measuring module is used for executing the following steps:
and determining the length of the steel plate to be measured according to the preset speed, the first time and the second time.
The operation and effect of the above device in the process of executing the method can be referred to the description of the above method, and will not be described herein again.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains; it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof; the scope of the invention is limited only by the appended claims.
Claims (10)
1. A steel plate dimension measurement method based on line structured light is characterized by comprising the following steps:
acquiring the inclination angle and the plate head of a steel plate to be detected;
adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected;
moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the plate tail of the steel plate to be detected, marking a first time when the linear structured light scans to the plate head, and marking a second time when the linear structured light scans to the plate tail; the linear structure light moves from the initial scanning position to the head until the tail of the board is scanned and stops;
acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line-structured light scanning process;
extracting the width of the steel plate to be detected from the scanning image group;
and determining the length of the steel plate to be measured according to the preset speed, the first time and the second time.
2. The method as claimed in claim 1, wherein before the obtaining of the inclination angle and the plate head of the steel plate to be measured, the method further comprises:
detecting whether an in-place signal is sent out; the in-place signal is used for indicating that the steel plate to be measured reaches a measuring station;
if the in-place signal is sent out, executing the step to obtain the inclination angle and the plate head of the steel plate to be detected;
and if the in-place signal is not sent out, continuing to wait for the in-place signal.
3. The method as claimed in claim 1, wherein the adjusting the line structured light to the initial scanning position according to the tilt angle and the plate head comprises:
according to the inclination angle and the plate head, the line structured light is adjusted to be parallel to the edge of the plate head;
translating the line structure light to the initial scanning position.
4. The method as claimed in claim 1, wherein the extracting the width of the steel plate to be measured from the scanning image group includes:
extracting the central line of line structured light from each frame of image;
calibrating the central line, and acquiring the width of the steel plate in each frame of image;
removing abnormal values of the width of the steel plate in all the images, and acquiring the mode of the residual width;
and determining the mode as the width of the steel plate to be measured.
5. The method as claimed in claim 4, wherein the extracting the centerline of the line structured light from each frame of image comprises:
the centerline of line structured light is extracted from each frame of image according to the following formula:
wherein ,f（x，y) Is a line-structured light stripe image (x，y) The gray-value of (a) is,Ta threshold value for the extraction of the fringes,g（u，v) Is after extraction inu，v) A gray value of (b) andu＝x－w 0 ，v＝y－h 0 ，w 0 for the number of offset columns in the image,h 0 the number of offset lines in the image;
optimizing the centerline according to the formula:
wherein ,g（u，v) In order to preliminarily extract the stripe region,h（i，j) To optimize the fringe area (i，j) At a gray value of (b), andi=u-w 1 ，j=v-h 1 ，w 1 ，h 1 respectively, the number of columns and rows of fringe fields offset.
6. The method as claimed in claim 4, wherein the calibrating the center line to obtain the width of the steel plate in each frame of image includes:
calibrating camera parameters according to the following formula:
calibrating the plane parameters of the line structured light according to the following formula:
wherein ,（x i ，y i ，z i ) Coordinates of the stripes on the checkerboard under the camera coordinate system are calibrated for the checkerboard,nis used forThe number of stripes on a straight line.
7. The method for measuring the dimension of the steel plate based on the line structured light according to claim 4, wherein the step of obtaining the mode of the remaining width after removing the abnormal values of the width of the steel plate in all the images comprises:
the mode of the residual width is obtained according to the following formula:
wherein ,（u，v) Is the center line (a)X c ,Y c ,Z c ) Is the only spatial point corresponding to a point on the image in the camera coordinate system.
8. The method as claimed in claim 1, wherein the determining the length of the steel plate to be measured according to the preset speed, the first time and the second time includes:
determining the length of the steel plate to be measured according to the following formula:
wherein ,Lis the length of the steel plate to be measured,Vin order to be said preset speed, the speed of the motor is set,t 0 as the first time is a time of day,t 1 is the second time.
9. A steel plate size measuring system based on line structured light, for performing a method of measuring a size of a steel plate based on line structured light according to any one of claims 1 to 8, the steel plate size measuring system comprising:
the actuating mechanism module comprises a servo motor unit, a switch and a trigger signal unit and is used for controlling the starting and the closing of the steel plate dimension measuring system;
the object in-place detection module is used for executing the following steps:
before the inclination angle and the plate head of the steel plate to be detected are obtained, whether an in-place signal is sent out is detected;
a structured light width measurement module for performing the steps of:
acquiring the inclination angle and the plate head of a steel plate to be detected;
adjusting the line structured light to an initial scanning position according to the inclination angle and the plate head; the initial scanning position is in front of the plate head and not on the steel plate to be detected;
moving the linear structured light at a constant speed according to a preset speed until the linear structured light scans to the plate tail of the steel plate to be detected, marking a first time when the linear structured light scans to the plate head, and marking a second time when the linear structured light scans to the plate tail; the linear structure light moves from the initial scanning position to the head until the tail of the board is scanned and stops;
acquiring a scanning image group of the steel plate to be detected; the scanning image group comprises each frame image in the line structured light scanning process;
extracting the width of the steel plate to be detected from the scanning image group;
the structured light length measuring module is used for executing the following steps:
and determining the length of the steel plate to be measured according to the preset speed, the first time and the second time.
10. The line structured light based steel sheet sizing system of claim 9 further comprising a hardware structure comprising:
the measuring device comprises a moving guide roller and a measuring device arranged on the moving guide roller; the measuring device can move along the moving guide roller;
the measuring device includes:
the industrial camera is provided with a lens, and the lens is used for acquiring the scanning image group;
a line-structured light emitter for emitting line-structured light;
and the heat insulation and dissipation device is arranged at the tail ends of the industrial camera and the line-structured light emitter and is used for keeping the temperature balance of the industrial camera and the line-structured light emitter.
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