CN116202423A - Line laser two-dimensional positioning method based on laser triangulation ranging - Google Patents
Line laser two-dimensional positioning method based on laser triangulation ranging Download PDFInfo
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- CN116202423A CN116202423A CN202310404679.XA CN202310404679A CN116202423A CN 116202423 A CN116202423 A CN 116202423A CN 202310404679 A CN202310404679 A CN 202310404679A CN 116202423 A CN116202423 A CN 116202423A
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- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000012545 processing Methods 0.000 claims abstract description 10
- 239000000523 sample Substances 0.000 claims abstract description 5
- 238000005259 measurement Methods 0.000 claims description 14
- 230000005484 gravity Effects 0.000 claims description 12
- 238000003384 imaging method Methods 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 9
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 3
- 230000011218 segmentation Effects 0.000 claims description 3
- 238000009434 installation Methods 0.000 abstract 2
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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
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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
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Abstract
The invention discloses a line laser two-dimensional positioning method based on laser triangular ranging, which utilizes a measuring device comprising an image acquisition module, an installation frame, a laser projector and a control processing system, wherein the image acquisition module, the installation frame and the laser projector form a measuring probe, and the method uses two measuring probes and one control processing system. The method comprises the following steps: the calibration block is placed at the target position and is in a triangular relation with the two measuring devices, and the control processing system finishes the calibration of the target position according to the current laser line image; and (3) removing the calibration block, moving into the target positioning object to position, and obtaining the relative distance from the target object to the target position based on a laser triangulation method through real-time calculation of the current laser line image in the positioning process. When the method is used for positioning the target object, the two-dimensional accurate positioning of the object to be positioned can be realized according to the auxiliary laser line and the image processing algorithm without complex equipment, complicated positioning flow and target material requirements.
Description
Technical Field
The invention belongs to the technical field of measurement, and particularly relates to a line laser two-dimensional positioning method based on laser triangulation ranging.
Background
The common laser triangulation positioning method uses point lasers and an image receiving unit to position the target in only one dimension, however, in most use scenes, we do not satisfy the positioning of the target in one dimension, but need to position the relative coordinates in two dimensions. In practical industrial application, it is risky to locate the data only, and we expect to obtain the data and see the real image at the same time, so as to perform mutual authentication. Finally, the point laser mode cannot identify the transverse displacement of a large target, and the object can be effectively solved through the line laser.
Disclosure of Invention
The invention aims to overcome the defects and provide a line laser two-dimensional positioning method based on laser triangulation ranging.
The invention adopts the technical scheme that: a line laser two-dimensional positioning method based on laser triangulation ranging comprises the following steps:
step A, fixing a laser projector and an image acquisition module to form a measurement module at a certain angle through a mounting frame, and placing the two measurement modules at a proper angle to form a triangular relationship with a target positioning position;
step B, before positioning, a calibration piece is placed at a target position for calibration, a control system judges the relative coordinates of an object to be positioned to the target position in real time during positioning, the calibration piece needs to be consistent with the shape of the target object, and the target object needs to be a columnar object;
and C, extracting a gray level center line of the laser line, solving the center of gravity of the gray level center line, judging the relative distance from the measured object to the measuring probe according to the center of gravity, and obtaining the relative coordinates from the measured object to the target position according to the relative distance from the target position to the two measuring modules.
The specific method of the step C is as follows: firstly, an image containing laser lines is acquired, filtering and gray threshold segmentation processing are carried out, and an image which is free of noise and has gray greater than a threshold value is obtained. Then calculating gray level gravity center points of the light stripe areas column by column, and setting the abscissa and ordinate of the pixel points as a variable x and a variable y and I respectively (x,y) Is the gray value of the pixel point with coordinates (x, y). Let the non-zero space of x columns be [ y1, y2 ]]The gray center of gravity x of x columns c The method comprises the following steps:
set the horizontal non-zero area of the laser center line as [ x1, x2]The ordinate L of the laser line center c The method comprises the following steps:
ordinate L of laser line center c The displacement cc ' on the imaging plane of the camera and the distance pp ' between the calibration plane and the measurement plane accord with the Snell's law, and the formula can be obtained by combining the similar triangle formula:
wherein alpha is the included angle between the optical axis of the camera and the imaging plane, beta is the included angle between the optical axis of the camera and the calibration plane, gc and gp are the distances between the lens g and the imaging plane and the calibration plane along the optical axis, and the distances can be obtained through calibration. According to the above formula, the distance pp 'of the measurement plane to the calibration plane can be solved when the offset cc' of the laser line on the image is known.
According to the sea theory, the formula is obtained:
where q is half the perimeter of triangle ap1p2, am is the height of triangle ap1p2, ap1 is the distance from target a to camera p1, ap2 is the distance from target a to camera p2, and p1p2 is the distance from camera p1 to camera p 2. As described above, ap1, ap2 can be solved according to the offset of the laser line on the image, and p1p2 is a fixed parameter, and then the coordinates (p 1m, am) of the measured object can be solved. The relative coordinates of the measured object to the target position are the difference between the measured object coordinates and the target coordinates.
The beneficial effects of the invention are as follows:
when the line laser two-dimensional positioning method is used for positioning the measured object, the relative coordinates of the measured object to the target position can be positioned in two dimensions, the positioning condition can be observed by naked eyes while the method is used for positioning, and the method can identify the tiny displacement in the parallel direction under the condition of using only one measuring module and can realize high-precision target positioning.
Drawings
FIG. 1 is a schematic diagram of an apparatus for a line laser two-dimensional positioning method based on laser triangulation;
FIG. 2 is a block flow diagram of a line laser two-dimensional positioning method based on laser triangulation;
FIG. 3 is a schematic diagram of a laser triangulation method based on a line laser two-dimensional positioning method of laser triangulation;
FIG. 4 is a schematic diagram of a two-dimensional positioning principle of a line laser two-dimensional positioning method based on laser triangulation;
the reference numerals in the drawings are: 1 is an image acquisition module, 2 is a mounting frame, 3 is a laser projector, and 4 is a control processing system.
Detailed Description
The invention is further illustrated by the following examples and figures:
as shown in fig. 1, a device of a line laser two-dimensional positioning method based on laser triangulation distance measurement includes: an image acquisition module 1, a mounting frame 2, a laser projector 3, a control processing system 4. The image acquisition module 1 is used for acquiring image data; the laser projector 3 is used for emitting line laser; the mounting frame 2 is used for fixing the image acquisition module 1 and the laser projector 3; a control processing system 4 is connected to the mounting frame 2 for interacting with and powering the image acquisition module 1 and the laser projector 3;
as shown in fig. 2, the line laser two-dimensional positioning method based on laser triangulation ranging includes the following steps:
step A, fixing the laser projector 3 and the image acquisition module 1 to form a measurement module at a certain angle through the mounting frame 2, and placing the two measurement modules at a proper angle to form a triangular relationship with the target positioning position;
step B, before positioning, a calibration piece is placed at a target position for calibration, a control system judges the relative coordinates of an object to be positioned to the target position in real time during positioning, the calibration piece needs to be consistent with the shape of the target object, and the target object needs to be a columnar object;
and C, extracting a gray level center line of the laser line, solving the center of gravity of the gray level center line, judging the relative distance from the measured object to the measuring probe according to the center of gravity, and obtaining the relative coordinates from the measured object to the target position according to the relative distance from the target position to the two measuring modules.
The specific method of the step C is as follows: firstly, an image containing laser lines is acquired, filtering and gray threshold segmentation processing are carried out, and an image which is free of noise and has gray greater than a threshold value is obtained. Then calculating gray level gravity center points of the light stripe areas column by column, and setting the abscissa and ordinate of the pixel points as a variable x and a variable y and I respectively (x,y) Is the gray value of the pixel point with coordinates (x, y). Let the non-zero space of x columns be [ y1, y2 ]]The gray center of gravity x of x columns c The method comprises the following steps:
set the horizontal non-zero area of the laser center line as [ x1, x2]The ordinate L of the laser line center c The method comprises the following steps:
ordinate L of laser line center c The displacement cc ' on the imaging plane of the camera and the distance pp ' between the calibration plane and the measurement plane accord with the Snell's law, and the formula can be obtained by combining the similar triangle formula:
wherein alpha is the included angle between the optical axis of the camera and the imaging plane, beta is the included angle between the optical axis of the camera and the calibration plane, gc and gp are the distances between the lens g and the imaging plane and the calibration plane along the optical axis, and the distances can be obtained through calibration. According to the above formula, the distance pp 'of the measurement plane to the calibration plane can be solved when the offset cc' of the laser line on the image is known.
According to the sea theory, the formula is obtained:
where q is half the perimeter of triangle ap1p2, am is the height of triangle ap1p2, ap1 is the distance from target a to camera p1, ap2 is the distance from target a to camera p2, and p1p2 is the distance from camera p1 to camera p 2. As described above, ap1, ap2 can be solved according to the offset of the laser line on the image, and p1p2 is a fixed parameter, and then the coordinates (p 1m, am) of the measured object can be solved. The relative coordinates of the measured object to the target position are the difference between the measured object coordinates and the target coordinates.
The actual effect of the technology is commonly influenced by a plurality of factors such as the included angle of the two measuring modules, the resolution of the camera, the included angle of the camera and the laser, the focal length of the camera and the like, wherein the core is the positioning precision of the measuring modules. The test is carried out by using an industrial camera with 500 ten thousand pixels and a fixed focus lens with 55mm, and the positioning precision of a target object with a distance of 1m is higher than 0.1mm.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (2)
1. A line laser two-dimensional positioning method based on laser triangulation ranging is characterized in that: the method comprises the following steps:
step A, fixing a laser projector and an image acquisition module to form a measurement module at a certain angle through a mounting frame, and placing the two measurement modules at a proper angle to form a triangular relationship with a target positioning position;
step B, before positioning, a calibration piece is placed at a target position for calibration, a control system judges the relative coordinates of an object to be positioned to the target position in real time during positioning, the calibration piece needs to be consistent with the shape of the target object, and the target object needs to be a columnar object;
and C, extracting a gray level center line of the laser line, solving the center of gravity of the gray level center line, judging the relative distance from the measured object to the measuring probe according to the center of gravity, and obtaining the relative coordinates from the measured object to the target position according to the relative distance from the target position to the two measuring modules.
2. The line laser positioning method based on laser triangulation according to claim 1, wherein the line laser positioning method is characterized in that: the specific method of the step C is as follows: firstly, an image containing laser lines is acquired, filtering and gray threshold segmentation processing are carried out, and an image which is free of noise and has gray greater than a threshold value is obtained. Then calculating gray level gravity center points of the light stripe areas column by column, and setting the abscissa and ordinate of the pixel points as a variable x and a variable y and I respectively (x,y) Is a pixel point with coordinates of (x, y)Is a gray value of (a). Let the non-zero space of x columns be [ y1, y2 ]]The gray center of gravity x of x columns c The method comprises the following steps:
set the horizontal non-zero area of the laser center line as [ x1, x2]The ordinate L of the laser line center c The method comprises the following steps:
ordinate L of laser line center c The displacement cc ' on the imaging plane of the camera and the distance pp ' between the calibration plane and the measurement plane accord with the Snell's law, and the formula can be obtained by combining the similar triangle formula:
wherein alpha is the included angle between the optical axis of the camera and the imaging plane, beta is the included angle between the optical axis of the camera and the calibration plane, gc and gp are the distances between the lens g and the imaging plane and the calibration plane along the optical axis, and the distances can be obtained through calibration. According to the above formula, the distance pp 'of the measurement plane to the calibration plane can be solved when the offset cc' of the laser line on the image is known.
According to the sea theory, the formula is obtained:
where q is half the perimeter of triangle ap1p2, am is the height of triangle ap1p2, ap1 is the distance from target a to camera p1, ap2 is the distance from target a to camera p2, and p1p2 is the distance from camera p1 to camera p 2. As described above, ap1, ap2 can be solved according to the offset of the laser line on the image, and p1p2 is a fixed parameter, and then the coordinates (p 1m, am) of the measured object can be solved. The relative coordinates of the measured object to the target position are the difference between the measured object coordinates and the target coordinates.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117451657A (en) * | 2023-10-23 | 2024-01-26 | 南京审计大学 | Remote long-wave infrared laser measuring instrument and measuring method under flue gas interference environment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117451657A (en) * | 2023-10-23 | 2024-01-26 | 南京审计大学 | Remote long-wave infrared laser measuring instrument and measuring method under flue gas interference environment |
| CN117451657B (en) * | 2023-10-23 | 2024-06-25 | 南京审计大学 | Remote long-wave infrared laser measuring instrument and measuring method under flue gas interference environment |
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