CN111397511A - Method and device for performing monocular three-dimensional measurement by using object translation - Google Patents
Method and device for performing monocular three-dimensional measurement by using object translation Download PDFInfo
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- CN111397511A CN111397511A CN202010255057.1A CN202010255057A CN111397511A CN 111397511 A CN111397511 A CN 111397511A CN 202010255057 A CN202010255057 A CN 202010255057A CN 111397511 A CN111397511 A CN 111397511A
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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
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
Abstract
The invention relates to a method and a device for monocular three-dimensional measurement by using object translation, which move a measured object at a constant speed through a transmission belt, shoot images when the object is at different positions, determine the aberration of a measuring point on the two images through characteristic point matching, and determine the spatial position of the measured point by using the geometric relationship among the aberration, the movement distance and the spatial position, thereby realizing the three-dimensional measurement of the measured object. The monocular three-dimensional measuring device does not need structured light for projection, has a simple structure, directly images through the camera, has clear images, and can realize continuous real-time three-dimensional measurement of moving objects under the condition of not influencing the movement of the objects. The method and the device for monocular three-dimensional measurement by using object translation have important practical value.
Description
Technical Field
The invention belongs to the field of three-dimensional measurement, and relates to a method and a device for performing monocular three-dimensional measurement by using object translation.
Background
Currently, there are two main types of monocular stereo measurement methods:
1. the camera is moved to shoot images at different positions, or a binocular stereo vision system is formed by adopting a mirror reflection method, and stereo measurement is carried out by utilizing the binocular stereo vision method. When this method is used, the camera movement is more demanding (e.g. measurement of the movement distance), and the mirror surface reduces the resolution of the image. In addition, the two modes both require the measured object to be kept still, and the continuous three-dimensional measurement requirement of the object is difficult to realize.
2. The structured light is projected on a measured object, and the three-dimensional information is measured by using the deformation of the structured light. The adoption of the method needs an additional optical system, and leads to a complex structure of the measuring system.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method and a device for performing monocular three-dimensional measurement by using object translation.
The technical scheme adopted by the invention is as follows:
a method for monocular three-dimensional measurements using object translation, comprising:
establishing an O-XYZ three-dimensional coordinate system by taking the center of an image plane of a monocular camera as an origin O, taking the direction vertical to the image plane as a Z axis and the image plane as an XOY plane; t is t1At the moment, the monocular camera takes a first image, and the object point P forms an image point P1 on the image plane; then, the object point P moves linearly at a constant velocity V parallel to the image plane at t2When the moment reaches the position P ', the monocular camera takes a second image, and the object point P' forms an image point P2 on the image plane;
calculating the spatial three-dimensional coordinate (x) of the object point Pp,yp,zp)：
In the formula (1), b is V · Δ t, and Δ t is t2-t1(ii) a d is the aberration between the image points P1 and P2, and is obtained by calculation through a feature point matching algorithm; f is the focal length of the monocular camera, (x)C,yC) The coordinate of the image point P1 corresponding to the object point P on the image plane.
Further, the specific process of determining the aberration d is as follows:
in the first and second images, the coordinates of the central point corresponding to the origin O are both (0.5L, 0.5W), wherein L is the transverse resolution of the image, and W is the longitudinal resolution of the image;
in the first image, the pixel point coordinate corresponding to the image point P1 is (i)1,j1)；
In the second image, the pixel point coordinate corresponding to the pixel point P2 is (i)2,j2)；
Calculating the distance d 'of the image point P1 from the center point of the first image'1Calculating the distance d 'of the image point P2 from the center point of the second image'2The calculation formula is as follows:
in the formula (2), px is the width of each pixel of the monocular camera, and py is the height of each pixel of the monocular camera;
when the image points P1 and P2 are located on the same side as the origin O, the aberration d ═ d'1-d'2|；
When the image points P1 and P2 are located on different sides of the origin O, the aberration d ═ d'1+d'2|。
Furthermore, T.V is less than or equal to px, and T is the shutter speed of the monocular camera.
The utility model provides an utilize object translation to carry out monocular three-dimensional measuring device, is in including door type frame and setting door type frame below, be used for carrying the horizontal transmission band of object uniform velocity removal, the fixed monocular camera that sets up in door type frame top, the monocular camera is facing down the transmission band.
Furthermore, the device for performing monocular three-dimensional measurement by using object translation further comprises a sliding block and a camera holder, the portal frame comprises a beam and two upright posts, and two ends of the beam are respectively fixedly connected with the top ends of the two upright posts; the sliding block is matched with the cross beam and can be fixed on the cross beam in a sliding way; the camera cloud platform is fixed the slider bottom, the monocular camera is fixed on the camera cloud platform.
Furthermore, a base is fixed at the bottom of each of the two upright posts.
The invention has the beneficial effects that:
the invention moves the measured object at a constant speed through the transmission belt, shoots images when the object is at different positions, determines the aberration of the measuring point on the two images through characteristic point matching, and determines the spatial position of the measured point by using the geometric relationship among the aberration, the movement distance and the spatial position, thereby realizing the three-dimensional measurement of the measured object. The monocular three-dimensional measuring device does not need structured light for projection, has a simple structure, directly images through the camera, has clear images, and can realize continuous real-time three-dimensional measurement of moving objects under the condition of not influencing the movement of the objects. The method and the device for monocular three-dimensional measurement by using object translation have important practical value, and are particularly applied to factory assembly line production, for example, after three-dimensional imaging, the method and the device can be matched with other image processing means to diagnose and evaluate products.
Drawings
FIG. 1 is a schematic diagram of a monocular three-dimensional measurement method of the present invention;
FIG. 2 is a schematic structural diagram of a monocular three-dimensional measurement device according to the present invention;
FIG. 3 is a left side view of FIG. 2;
FIG. 4 is a schematic view of a fitting structure between a slider and a cross member;
reference numerals: 1-upright column, 2-beam, 3-slide block, 4-camera platform and 5-base.
Detailed Description
The method and apparatus for monocular three-dimensional measurement using object translation according to the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, a method for monocular three-dimensional measurement using translation of an object, comprising:
establishing an O-XYZ three-dimensional coordinate system by taking the center of an image plane of a monocular camera as an origin O, taking the direction vertical to the image plane as a Z axis and the image plane as an XOY plane; o' is the optical center of the monocular camera; by the principle of pinhole imaging and light linear propagation, the object point reflected light passes through the optical center and then is projected onto an image plane to form an inverted image point.
t1At the moment, the monocular camera takes a first image, and the object point P forms an image point P1 on the image plane; then, the object point P moves linearly at a constant velocity V parallel to the image plane at t2The moment reaches the position P ', the monocular camera takes a second image, and the object point P ' (i.e., the object point P moving to the position P ') forms an image point P2 (t) on the image plane1、t2The object point is required to be ensured to be within the shooting range of the monocular camera at all times);
calculating the spatial three-dimensional coordinate (x) of the object point Pp,yp,zp)：
In the formula (1), b is V · Δ t, and Δ t is t2-t1(ii) a d is the aberration between the image points P1 and P2, and is obtained by calculation through a feature point matching algorithm; f is the focal length of the monocular camera, (x)C,yC) The coordinate of the image point P1 corresponding to the object point P on the image plane.
The specific process for determining the aberration d is as follows:
in the first and second images, the coordinates of the central point corresponding to the origin O are both (0.5L, 0.5W), wherein L is the transverse resolution of the image, and W is the longitudinal resolution of the image;
in the first image, the pixel point coordinate corresponding to the image point P1 is (i)1,j1)；
In the second image, the pixel point coordinate corresponding to the pixel point P2 is (i)2,j2)；
Calculating the distance d 'of the image point P1 from the center point of the first image'1Calculating the distance d 'of the image point P2 from the center point of the second image'2The calculation formula is as follows:
in the formula (2), px is the width of each pixel of the monocular camera, and py is the height of each pixel of the monocular camera;
when the image points P1 and P2 are located on the same side as the origin O, the aberration d ═ d'1-d'2|；
When the image points P1 and P2 are located on different sides of the origin O, the aberration d ═ d'1+d'2|。
Because the method is used for shooting in the moving process, the moving speed V and the shooting speed of the monocular camera can influence the measurement result, and the following conditions need to be met: and T.V is less than or equal to px, and T is the shutter speed of the monocular camera.
Generally, when px is 10um and the moving speed V is 1m/s, the monocular camera shutter speed is 10us, i.e. a high-speed camera is required. If a normal camera is used and the shutter speed is set at 1/1000s (a normal electronic shutter can be implemented), the error of the moving distance b is 1mm, and the final measurement error can be calculated according to the formula (1).
As shown in fig. 2 to 4, a device for monocular three-dimensional measurement by using object translation includes a gate-shaped frame and a horizontal conveyor belt arranged below the gate-shaped frame and used for carrying an object to move at a uniform speed, a monocular camera is fixedly arranged on the top of the gate-shaped frame, and the monocular camera faces downwards to the conveyor belt.
Specifically, the door-shaped frame comprises a cross beam 2 and two vertical columns 1, and two ends of the cross beam 2 are respectively fixedly connected with the top ends of the two vertical columns 1. The device for monocular three-dimensional measurement by using object translation further comprises a sliding block 3 and a camera cloud platform 4, wherein the sliding block 3 is matched with the beam 2 and can be fixed on the beam 2 in a sliding manner. The camera cloud platform 4 is fixed in the bottom of the sliding block 3 through screws, and the monocular camera is fixed on the camera cloud platform 4.
In this embodiment, the bottoms of the two vertical columns 1 are respectively fixed with a base 5, and the two bases 5 have the same height, so as to ensure that the beam 2 is in a horizontal state.
In this embodiment, the upright columns 1 are made of steel pipes and the cross beams 2 are made of h-shaped steel, the upright columns 1 are welded with the cross beams 2, and the base 5 is welded with the corresponding upright columns 1.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any alternative or alternative method that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the scope of the present invention.
Claims (6)
1. A method for monocular three-dimensional measurements using object translation, comprising:
establishing an O-XYZ three-dimensional coordinate system by taking the center of an image plane of a monocular camera as an origin O, taking the direction vertical to the image plane as a Z axis and the image plane as an XOY plane; t is t1At the moment, the monocular camera takes a first image, and the object point P forms an image point P1 on the image plane; then, the object point P moves linearly at a constant velocity V parallel to the image plane at t2When the moment reaches the position P ', the monocular camera takes a second image, and the object point P' forms an image point P2 on the image plane;
calculating the spatial three-dimensional coordinate (x) of the object point Pp,yp,zp)：
In the formula (1), b is V · Δ t, and Δ t is t2-t1(ii) a d is the aberration between the image points P1 and P2, and is obtained by calculation through a feature point matching algorithm; f is the focal length of the monocular camera, (x)C,yC) The coordinate of the image point P1 corresponding to the object point P on the image plane.
2. The method for monocular three-dimensional measurement using object translation according to claim 1, wherein the specific process of determining the aberration d is:
in the first and second images, the coordinates of the central point corresponding to the origin O are both (0.5L, 0.5W), wherein L is the transverse resolution of the image, and W is the longitudinal resolution of the image;
in the first image, the pixel point coordinate corresponding to the image point P1 is (i)1,j1)；
In the second image, the pixel point coordinate corresponding to the pixel point P2 is (i)2,j2)；
Calculating the distance d 'of the image point P1 from the center point of the first image'1Calculating the distance d 'of the image point P2 from the center point of the second image'2The calculation formula is as follows:
in the formula (2), px is the width of each pixel of the monocular camera, and py is the height of each pixel of the monocular camera;
when the image points P1 and P2 are located on the same side as the origin O, the aberration d ═ d'1-d′2|；
When the image points P1 and P2 are located on different sides of the origin O, the aberration d ═ d'1+d′2|。
3. The method for monocular three-dimensional measurement using object translation according to claim 2, wherein T-V ≦ px, and T is a monocular camera shutter speed.
4. The utility model provides an utilize object translation to carry out monocular three-dimensional measuring device which characterized in that, is in including door type frame and setting door type frame below, be used for carrying the object at the uniform velocity horizontal transmission band that removes, the fixed monocular camera that sets up in door type frame top, the monocular camera is facing down the transmission band.
5. The device for monocular three-dimensional measurement using object translation according to claim 4, further comprising a slider (3) and a camera pan-tilt (4), wherein the gantry comprises a beam (2) and two columns (1), and two ends of the beam (2) are respectively fixedly connected with top ends of the two columns (1); the sliding block (3) is matched with the cross beam (2) and can be fixed on the cross beam (2) in a sliding way; the camera cloud platform (4) is fixed at the bottom of the sliding block (3), and the monocular camera is fixed on the camera cloud platform (4).
6. The device for monocular three-dimensional measurement with object translation according to claim 5, wherein a base (5) is fixed to the bottom of each of the two columns (1).
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| CN112907647A (en) * | 2021-01-26 | 2021-06-04 | 公安部交通管理科学研究所 | Three-dimensional space size measurement method based on fixed monocular camera |
| CN113873214A (en) * | 2021-09-26 | 2021-12-31 | 翁均明 | Scanning type portable equipment stereo photography method |
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Application publication date: 20200710 |