CN109655837B - Laser ranging method and laser range finder - Google Patents
Laser ranging method and laser range finder Download PDFInfo
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- CN109655837B CN109655837B CN201710937738.4A CN201710937738A CN109655837B CN 109655837 B CN109655837 B CN 109655837B CN 201710937738 A CN201710937738 A CN 201710937738A CN 109655837 B CN109655837 B CN 109655837B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/46—Indirect determination of position data
- G01S17/48—Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/497—Means for monitoring or calibrating
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Abstract
The embodiment of the invention belongs to the technical field of laser ranging, and relates to a laser ranging method and a laser range finder, wherein the method comprises the steps of irradiating a first laser beam and a second laser beam to the surface of a measured object at a certain incident angle theta, reflecting the first laser beam and the second laser beam by the surface of the measured object to form two reflecting light spots on an area array image sensor, acquiring position coordinates of the two reflecting light spots on a photosensitive surface before and after the measured object moves, and obtaining the relative distances d1 and d2 of the two reflecting light spots according to the position coordinates; obtaining the displacement of the measured object in the axial direction of the rotating shaft according to the incident angle theta, the relative distance d1 and the relative distance d 2; the laser range finder is used for implementing the method. According to the technical scheme provided by the embodiment of the invention, the anti-interference performance of the area array image sensor can be improved by increasing the number of the measuring points, so that the measuring precision is improved.
Description
Technical Field
The embodiment of the invention belongs to the technical field of laser ranging, and particularly relates to a laser ranging method and a laser range finder.
Background
At present, in the field of displacement or distance measurement, the measurement mode is mainly divided into contact measurement and non-contact measurement, wherein laser measurement displacement or distance belongs to the most common one of non-contact measurement, and in the field of laser ranging, the displacement or distance is measured by adopting a timing and phase principle or a trigonometry principle.
For example, the displacement is measured by using the trigonometry principle, fig. 1 is a schematic diagram of measuring the displacement by using the trigonometry principle, a laser head emits a beam of laser, the laser is focused on the surface of a measured object through a focusing lens, finally reflected light passes through a receiving lens and is emitted into a surface image sensor to form reflected light spots, and when the object moves perpendicular to incident light, the reflected light spots on the surface array image sensor also move along with the incident light, so that the actual moving distance of the measured object can be calculated by the reflected light spot displacement in the surface array image sensor through a specific proportional relation, and the displacement of the measured object can be specifically obtained by using the following formula:
wherein S is the actual displacement of the object, S' is the displacement of the reflected light spot on the area array image sensor, a and b are constants related to the structural design of the area array image sensors of different models, and alpha and
by angle, see the notation in FIG. 1, when the datum level is fixed, α and
is a constant.
The inventor finds that the prior art has at least the following problems in the process of implementing the invention:
the disadvantage of the above triangle method for measuring displacement is that, on one hand, the area array image sensor is an instrument for converting optical signals into electrical signals, and there is a certain noise, and due to the existence of the noise, the light spot central point will swing in a small random range, as shown in fig. 2, and the noise will always participate in the calculation of the displacement of the reflected light spot, thereby affecting the accuracy of the final measurement result; on the other hand, due to the fact that the surface material and the placing position of the measured object are different, and the external light environment is different, images collected by the area array image sensing device are inconsistent, the position, the brightness, the shape and the like of the reflected light spots are inconsistent, the central point of the reflected light spots swings left and right on the area array image sensor, and finally fluctuation occurs when the calculated actual displacement of the measured object is caused.
Disclosure of Invention
In view of this, the embodiment of the invention provides a laser ranging method and a laser range finder, which are based on the trigonometry principle, and adopt a differential design idea to suppress noise in an area array image sensor, so as to realize displacement measurement with higher precision and more stability. The embodiment of the invention adopts the following specific technical scheme:
in a first aspect, an embodiment of the present invention provides a laser ranging method, including:
irradiating a first laser beam and a second laser beam to the surface of a measured object at a certain incident angle theta, wherein the first laser beam and the second laser beam are reflected by the surface of the measured object and form two reflection light spots on a photosensitive surface of an area array image sensor after being scaled by the multiplying power of an optical receiving assembly, the incident angle theta is a preset constant, the first laser beam can be coincided with the second laser beam when rotating along a specific rotating shaft for a certain angle, and the rotating shaft is perpendicular to the surface of the measured object;
acquiring position coordinates of the two reflection light spots on the photosensitive surface, and obtaining the relative distance d1 of the two reflection light spots according to the position coordinates;
when the measured object is displaced in the axial direction of the rotating shaft, the positions of the two reflected light spots on the photosensitive surface of the area array image sensor are correspondingly changed, the position coordinates of the two reflected light spots on the photosensitive surface after the measured object is displaced are obtained, and the relative distance d2 of the two reflected light spots is obtained according to the changed position coordinates;
and acquiring the displacement of the measured object in the axial direction of the rotating shaft according to the incident angle theta and the relative distance d1 and d 2.
Further, when the object to be measured is displaced in the axial direction of the rotating shaft, the light spot movement tracks of the two reflected light spots on the photosensitive surface of the area array image sensor are not overlapped and are parallel to each other.
Further, the first and second laser beams with an incident angle of θ, or
And emitting a laser beam by a laser emitter, and forming the first laser beam and the second laser beam with an incidence angle theta by a light splitting device.
Further, the method further comprises:
and adjusting the relative position and angle of the area array image sensor and the optical receiving component so as to adjust the measuring range of the laser measuring instrument.
Further, the method further comprises:
and adjusting the incident angle theta to ensure that the positions of the two reflection light spots on the photosensitive surface of the area array image sensor do not exceed the boundary of the photosensitive surface when the measured object displaces within the adjusted measuring range.
Further, after the object to be measured is displaced in the axial direction of the rotating shaft, the method further includes:
and acquiring the moving distances of the two reflected light spots on the photosensitive surface of the area array image sensor, and correcting the relative distance of the two reflected light spots according to the moving distances of the two reflected light spots when the absolute value of the difference of the moving distances of the two reflected light spots is larger than a preset threshold value, otherwise, not correcting the relative distance of the two reflected light spots.
In a second aspect, an embodiment of the present invention further provides a laser range finder, including a laser emitting device, an optical receiving component, an area array image sensor and a processing unit, where the laser emitting device, the area array image sensor and the optical receiving component are sequentially arranged from top to bottom, and the area array image sensor is electrically connected to the processing unit;
the laser emitting device is used for emitting a first laser beam and a second laser beam, and the first laser beam and the second laser beam are enabled to irradiate the surface of a measured object at a certain incident angle;
the optical receiving assembly is used for transmitting the first laser beam and the second laser beam to a photosensitive surface of the area array image sensor after multiplying power scaling is carried out on the laser reflected by the surface of the measured object, and two reflected light spots are formed on the photosensitive surface;
the processing unit is used for obtaining the relative distance between the two reflected light spots before and after the measured object moves, and obtaining the displacement of the measured object according to the incident angle and the relative distance between the two reflected light spots before and after the measured object moves.
Optionally, the laser emitting device includes two laser emitters, and the two laser emitters are configured to emit a first laser beam and a second laser beam, so that the first laser beam and the second laser beam irradiate the surface of the object to be measured at a certain incident angle.
Optionally, the laser emitting device includes a laser emitter and a beam splitting device that set gradually from top to bottom, the beam splitting device is used for with the laser that laser emitter launches carries out the beam splitting and handles, forms first laser beam and second laser beam, and makes first laser beam and second laser beam shine to the testee surface with certain incident angle.
Further, the size of the photosensitive surface of the area array image sensor is matched with the scaling factor of the optical receiving component.
Further, the area array image sensor and the optical receiving assembly are arranged in a non-perpendicular mode.
According to the laser ranging method and the laser range finder provided by the embodiment of the invention, a single measuring laser beam is changed into a double beam, two beams of laser are projected on the surface of a measured object, so that two reflected light spots are formed on the area array image sensor, when the measured object moves, the actual displacement of the measured object is further obtained by obtaining the difference relative position of the two reflected light spots, and the mode can improve the anti-interference performance of the area array image sensor by increasing the number of measuring points, thereby improving the measuring precision.
Drawings
While the drawings needed to describe the invention or prior art arrangements in a more complete description of the embodiments or prior art are briefly described below, it should be apparent that the drawings described below are illustrative of some embodiments of the invention and that other drawings may be derived therefrom by those skilled in the art without the benefit of the inventive faculty.
Fig. 1 is a schematic diagram of a conventional laser ranging method according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating the jitter of the reflected light spot in the conventional laser ranging process according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a laser range finder provided in an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an embodiment of a laser range finder according to the present invention;
FIG. 5 is a schematic structural diagram of another embodiment of a laser range finder according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a light splitting device according to an embodiment of the present invention;
fig. 7 shows an arrangement of an area array image sensor and an optical receiving element according to an embodiment of the present invention;
FIG. 8 is a flowchart of a laser ranging method according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a laser optical path of a laser measuring instrument provided in an embodiment of the present invention;
FIG. 10 is a schematic diagram of the working principle of a laser measuring instrument according to an embodiment of the present invention;
fig. 11 is a schematic view of the movement traces of two reflected light spots in the same straight line according to the embodiment of the present invention;
FIG. 12 is a schematic diagram of two parallel movement traces of the reflected light spots provided by the embodiment of the present invention;
fig. 13 is another schematic diagram of the movement traces of two reflected light spots being on the same straight line according to the embodiment of the present invention;
FIG. 14 is another schematic diagram of two parallel movement traces of the reflected light spots according to the embodiment of the present invention;
fig. 15 is a schematic diagram of the jitter of the reflected light spot according to the embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms "first," "second," and the like in the description and claims of the present invention and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
The embodiment of the invention provides a laser range finder, which is shown in a schematic structural diagram in fig. 3 and comprises a laser emitting device 100, an optical receiving component 200, an area array image sensor 300 and a processing unit (not shown in the figure), wherein the laser emitting device 100, the area array image sensor 200 and the optical receiving component 300 are sequentially arranged from top to bottom, and the area array image sensor 300 is electrically connected with the processing unit;
in the present embodiment, the laser emitting device 100 is configured to emit a first laser beam and a second laser beam, and irradiate the first laser beam and the second laser beam onto the surface of the object to be measured at a certain incident angle;
as an alternative of this embodiment, as shown in fig. 4, the laser emitting apparatus 100 includes two laser heads 101, and the two laser emitters 110 respectively emit a first laser beam and a second laser beam, so that the first laser beam and the second laser beam irradiate onto a surface of an object to be measured at a certain incident angle, where the two laser emitters 110 may be symmetrically arranged, or the positional relationship between the two laser emitters 110 satisfies: after one of the laser emitters 110 rotates by a certain angle along a certain rotation axis from its position, the rotated position completely coincides with the position of the other laser emitter 110, that is, the positional relationship between the two laser emitters 110 needs to ensure that the first laser beam and the second laser beam satisfy a symmetric relationship, or that the first laser beam and the second laser beam satisfy: the first laser beam rotates a certain angle along a certain rotating shaft and then is completely coincided with the second laser beam;
as another alternative of this embodiment, as shown in fig. 5, the laser emitting device 100 includes a laser emitter 110 and a light splitting device 120, which are sequentially arranged from top to bottom, and the light splitting device 120 is configured to split laser emitted by the laser emitter 110 to form a first laser beam and a second laser beam, and irradiate the first laser beam and the second laser beam onto a surface of an object to be measured at a certain incident angle, where the first laser beam and the second laser beam satisfy: the first laser beam rotates a certain angle along a certain rotating shaft and then is completely coincided with the second laser beam; here, the case where the first laser beam and the second laser beam are symmetrical is included. In this embodiment, the light splitting device 120 mainly refers to a prism system or a mirror system, and further refer to fig. 6, which is a structural example of the light splitting device 120, and by this structural example, the laser emitted by the laser emitter 110 can be converted into two beams of laser, and of course, other similar structures capable of splitting laser can be adopted on the premise of the concept of the present invention.
In this embodiment, the optical receiving assembly 200 is configured to transmit the first laser beam and the second laser beam after scaling the laser reflected by the surface of the object to be measured, onto the photosensitive surface of the area array image sensor 300, and form two reflected light spots on the photosensitive surface; specifically, the optical receiving assembly 200 is a lens assembly, and the magnification scaling is completed by a single aspheric mirror or a plurality of combined spherical mirrors, because the area of the area array image sensor 300 is limited in the present embodiment, a larger area of the area array image sensor 300 needs to be reduced to a smaller area of the area array image sensor 200 by the optical receiving assembly 200, so as to meet the range requirement of the laser range finder.
In the present embodiment, the size of the photosensitive surface of the area array image sensor 300 is adapted to the zoom ratio of the optical receiving component 200, the relative position of the area array image sensor 300 and the optical receiving component 200, and/or the range of the laser range finder, that is, the four parameters of the range of the laser range finder, the size of the photosensitive surface of the area array image sensor 300, the zoom ratio of the optical receiving component 200, and the relative position of the area array image sensor 300 and the optical receiving component 200 are related to each other, and when two of the parameters are fixed, the change of one of the two parameters which are not fixed affects the other parameter; for example, when the size of the light-sensitive surface of the area array image sensor 300 and the relative position of the area array image sensor 300 and the optical receiving component 200 are fixed, the range of the laser range finder will be related to the zoom ratio of the optical receiving component 200, and the larger the zoom ratio of the optical receiving component 200, the larger the range of the laser range finder. The optical receiving assembly 200 therefore, if the laser range finder is designed to be range-adjustable, the area array image sensor 300 can be correspondingly set to be a structure with adjustable magnification, or the area array image sensor 300 and the optical receiving assembly 200 can be set to be a structure with adjustable relative positions; it should be noted that the measurement accuracy is affected by the range of the laser range finder, and when the equivalent range is large, the accuracy is reduced, and at this time, the cost can be reduced by using a resin lens, the assembly process does not need to use a high-accuracy calibration table, the diameter of the lens is increased to increase the visual field range, and the placement position is adjusted to make the image in the whole range fall on the image sensor. Otherwise, a high-precision calibration table is needed for calibration, and small-size lenses and glass lenses are needed; further, the optical receiving assembly 200 may adopt different processes, different materials, different dimensions or installation positions according to the range of the laser range finder, for example, in the present embodiment, the optical receiving assembly 200 may be rotated for fine tuning the focal length to calibrate according to the individual difference of the lenses in the optical receiving assembly 200 to achieve the best performance.
As an alternative to the embodiment of the present invention, as shown in fig. 7, the area array image sensor 300 and the optical receiving assembly 200 are disposed in a non-perpendicular manner, and the optical receiving assembly employs an oblique lens, which is not perpendicular to the area array image sensor 300 but forms a certain angle with the area array image sensor 300, so that linearity of the measured distance can be ensured, and definition and resolution of the reflected light spot on the area array image sensor 300 can be ensured.
The processing unit is used for acquiring the relative distance between the two reflected light spots before and after the measured object moves, and acquiring the displacement of the measured object according to the incident angle and the relative distance between the two reflected light spots before and after the measured object moves; the specific processing procedure is explained in detail below; in this embodiment, the processing unit includes a data processor, a memory and related peripheral circuits, specifically integrates the functions of the current industrial camera circuit and the PC controller, and the processed data can be directly transmitted to each platform such as a computer, a PLC, a single chip microcomputer, and the like.
Based on the laser range finder described in the foregoing embodiment, an embodiment of the present invention further provides a laser range finding method, as shown in the flowchart illustrated in fig. 8 and the schematic laser path diagram illustrated in fig. 9, where the method includes:
s1, irradiating the first laser beam and the second laser beam to the surface of the object to be measured at a certain incident angle θ, wherein the first laser beam and the second laser beam form two reflection spots on the photosensitive surface of the area array image sensor 300 after being reflected by the surface of the object to be measured and being scaled by the magnification of the optical receiving assembly 200; the incident angle theta is a preset constant, the first laser beam rotates for a certain angle along a specific rotating shaft and can be superposed with the second laser beam, and the rotating shaft is vertical to the surface of the object to be measured; s2, acquiring position coordinates of the two reflection light spots on the photosensitive surface, and obtaining the relative distance d1 of the two reflection light spots according to the position coordinates;
s3, acquiring the position coordinates of the two reflected light spots on the photosensitive surface after the measured object is displaced, and obtaining the relative distance d2 of the two reflected light spots according to the changed position coordinates; when the object to be measured is displaced in the axial direction of the rotating shaft, the positions of the two reflected light spots on the photosensitive surface of the area array image sensor 300 change correspondingly;
s4, obtaining the displacement of the object to be measured in the axial direction of the rotating shaft according to the incidence angle theta and the relative distance d1 and d 2.
The above steps are explained in detail below, and specifically, in the present embodiment, the first laser beam and the second laser beam in step S1 satisfy: the first laser beam can be coincided with the second laser beam by rotating along a specific rotating shaft by a certain angle, and the rotating shaft is vertical to the surface of the measured object; here, the case where the first laser beam and the second laser beam are symmetrical is included; when the object to be measured is displaced in the axial direction of the rotating shaft, the position of the reflected light spot on the photosensitive surface of the area array image sensor 300 changes correspondingly;
for the generation form of the first laser beam and the second laser beam, the first laser beam and the second laser beam with the incident angle θ can be respectively emitted by two laser emitters 110, or one laser beam is emitted by one laser emitter 110, and then the first laser beam and the second laser beam with the incident angle θ are formed by the light splitting device 120; before the first laser beam and the second laser beam are irradiated to the surface of the measured object at a certain incident angle theta, the measured object is placed on one side of a laser light outlet of the laser range finder, and the upper surface of the measured object is positioned on a measuring reference surface, as shown in fig. 9, assuming that the measuring reference surface is at the position of position 1, the measured object moves from the measuring reference surface to the laser range finder or moves away from the laser range finder, and the moving distance of the measured object can be obtained by the laser range finder in real time within the range of the laser range finder;
further, the first laser beam and the second laser beam may form a light spot on the surface of the object to be measured, as shown in A, A ', B, and B' marked in fig. 9, where a is a center of the light spot formed on the surface of the object to be measured by the first laser beam when the object to be measured is located at the initial position, B is a center of the light spot formed on the surface of the object to be measured by the second laser beam when the object to be measured is located at the initial position, a 'is a center of the light spot formed on the surface of the object to be measured by the first laser beam after the object to be measured moves, and B' is a center of the light spot formed on the surface of the object to be measured by the second laser beam after the object to be measured moves, and the laser reflected by the surface of the object to be measured is transmitted to the photosensitive surface of the area array image sensor 300 after being scaled by the magnification of the optical receiving assembly 200 to form a reflected light, C ', D, and D', wherein C is the center of a reflected light spot formed on the photosensitive surface of the area array image sensor 300 by the first laser beam when the object to be measured is located at the initial position, D is the center of a reflected light spot formed on the photosensitive surface of the area array image sensor 300 by the second laser beam when the object to be measured is located at the initial position, C 'is the center of a reflected light spot formed on the photosensitive surface of the area array image sensor 300 by the first laser beam after the object to be measured moves, and D' is the center of a reflected light spot formed on the photosensitive surface of the area array image sensor 300 by the second laser beam after the object to be measured moves; in the displacement measurement process, measurement data can be obtained by acquiring the position coordinates of the centers C, C ', D, and D' of the reflected light spots, and the displacement of the measured object is obtained.
Referring to fig. 10 together, fig. 10 is a schematic diagram illustrating the operation principle of the laser range finder, when the position of the measured object is changed from position 1 to position 2, the relative distance between the two spots formed on the measured object by the first laser beam and the second laser beam is transformed from D1 to D2, and the relative distance between the reflected spots on the area array image sensor 300 is transformed from D1 to D2, because the changed curvature is constant, the following equation is satisfied:
(D1-D2)＝p(d1-d2)；
wherein p is a scaling factor, which is a constant related to the scaling factor of the optical receiving device 200, and the mapping table of the scaling factor of the optical receiving device 200 and p can be configured, and when the scaling factor of the optical receiving device 200 is constant, the value of p can be obtained from the mapping table;
assuming that the distance change of the measured object from position 1 to position 2 is a displacement DXSame displacement DXThe difference between D1 and D2 is in a certain proportional relation, and the proportionality constant is q, and the following equation is given:
DX＝q(D1-D2)；
the method comprises the following steps that a mapping table of q and theta can be configured, wherein q is a constant related to the incident angles theta of a first laser beam and a second laser beam, and the numerical value of q can be obtained from the mapping table of q and theta according to the set incident angle theta;
thus, the displacement D of the measured object from position 1 to position 2XThe reality can be represented by the following formula:
DX＝pq(d1-d2)；
the actual displacement of the object to be measured can be calculated by calculating the variation of the relative positions of the two reflected light spots on the area array image sensor 300, and the variation of the relative positions of the two reflected light spots is obtained by the position coordinates of the centers of the reflected light spots, and refer to fig. 11, which is a schematic diagram illustrating the movement of the reflected light spots on the photosensitive surface of the area array image sensor 300, and the reflected light spots formed by the first laser beam and the second laser beam on the photosensitive surface of the area array image sensor 300 are called as reflected light spot 1 and reflected light spot 2, respectively, when the object to be measured is from position 1 to position 2, the center position of the reflected light spot 1 is moved from C to C',the corresponding moving distance is a1, the center position of the reflection spot 2 moves from D to D ', the corresponding moving distance is a2, the relative distance between C and D is D1, the relative distance between C ' and D ' is D2, the values of a1, a2, D1 and D2 can be obtained based on the position coordinates of the reflection spot center C, C ', D and D ', and then the value of D1, a2, D1 and D2 can be obtainedXThe displacement amount of the object to be measured can be obtained by pq (d1-d 2).
As mentioned above, the first laser beam and the second laser beam satisfy that the incident first laser beam can be rotated by a certain angle along a specific rotation axis to coincide with the incident second laser beam, which includes the case that the first laser beam and the second laser beam are symmetric, however, the relationship between the movement tracks of the reflection spot 1 and the reflection spot 2 on the photosensitive surface of the area array image sensor 300 is different between the case that the first laser beam and the second laser beam are symmetric and the movement tracks of the reflection spot 1 and the reflection spot 2 on the photosensitive surface of the area array image sensor 300 are on a straight line when the first laser beam and the second laser beam are symmetric, as shown in fig. 11;
when the incident first laser beam rotates a certain angle along a specific rotation axis and can coincide with the incident second laser beam, and the first laser beam and the second laser beam are asymmetric, the movement tracks of the reflection spot 1 and the reflection spot 2 on the photosensitive surface of the area array image sensor 300 will be parallel to each other, as shown in fig. 12, in this embodiment, when the object to be measured is displaced in the axial direction of the rotation axis, the movement tracks of the two reflection spots on the photosensitive surface of the area array image sensor 300 are not overlapped and are parallel to each other, there is a case that when the movement tracks of the reflection spot 1 and the reflection spot 2 on the photosensitive surface of the area array image sensor 300 are on a straight line, there is a possibility that the spot centers of the reflection spot 1 and the reflection spot 2 cross the center line, as shown in fig. 13, which makes the positions of the reflection spot 1 and the reflection spot 2 to be exchanged, the position change can be recognized by further processing, so that the movement tracks of the reflection light spots 1 and 2 on the photosensitive surface of the area array image sensor 300 are staggered, as shown in fig. 14, the recognition processing is not needed, the subsequent calculation processing is facilitated, meanwhile, the effective acquisition surface of the area array image sensor 300 can be utilized as much as possible, the measuring range of the laser range finder is maximized, of course, under the condition that the center of the light spots crosses the center line, the calculation formula is correspondingly changed, and the displacement calculation formula of the measured object is changed as follows:
DX＝pq(d1+d2)。
in fact, due to various noises or other influencing factors, after the measured object is displaced, the reflected light spots formed by the two laser beams on the photosensitive surface of the area array image sensor 300 may shake, possibly one of the reflected light spots shakes, or both of the reflected light spots shake, and certainly, the reflected light spots on the photosensitive surface of the area array image sensor 300 may shake before the measured object moves, because the parameter involved in the displacement calculation is the relative distance between the two reflected light spots, in this embodiment, it may be assumed that the reflected light spots on the photosensitive surface of the area array image sensor do not shake before the measured object moves, and only the condition that the reflected light spots on the photosensitive surface of the area array image sensor 300 shake after the movement is considered, specifically, the reflected light spots 1 and the reflected light spots 2 may shake in the same direction, The jitter of the reverse direction and the opposite direction is that the relative distance between the two reflected light spots deviates from the true value only when the two reflected light spots simultaneously generate the jitter of the reverse direction or the opposite direction, similarly, since the parameter participating in the displacement calculation is the relative distance between the two reflected light spots, the jitter condition of one reflected light spot can be considered only, and the other reflected light spot is considered as a reference datum point without the jitter, in this embodiment, the jitter of the reflected light spot 2 is considered only, the position of the reflected light spot 1 is taken as a reference datum, then the corresponding moving distances of the reflected light spot 1 and the reflected light spot 2 on the photosensitive surface of the area array image sensor 300 are obtained, when the displacement sizes of the reflected light spot 1 and the reflected light spot 2 are not equal, the reflected light spot 2 is considered to be jittered, as shown in fig. 15, before the displacement of the measured object occurs, the light spot center of the reflected light spot 1 is located at the, the light spot center of the reflection light spot 2 is located at the position D, when the measured object is displaced, the light spot center of the reflection light spot 1 is located at the position C ', the light spot center of the reflection light spot 2 is originally located at the position D ', because the center of the jitter light spot is offset to the position D ', the relative distance between the reflection light spot 1 and the reflection light spot 2 is changed from D2 to D ' 2 when the measured object is displaced, the moving distance of the reflection light spot 1 is a1, the moving distance of the reflection light spot 2 is (a2+ D2-D ' 2), theoretically a1 is equal to a2, the deviation value generated by the jitter of the reflection light spot 1 is the absolute value of D2-D ' 2, when the absolute value of D2-D ' 2 is larger than the preset threshold value, the relative distance D ' 2 between C ' and D ' can be corrected according to the above deviation value, so that the relative distance D ' 2 between C ' and D ' tends to the true value D2, otherwise, the relative, by the method, the laser measurement precision can be greatly improved.
In this embodiment, the laser ranging method further includes adjusting the relative position and angle between the area array image sensor 300 and the optical receiving component to adjust the measuring range of the laser measuring instrument, so as to meet different scenes with different measuring requirements, and thus the application range of the laser measuring instrument can be effectively expanded; further, the laser ranging method provided in this embodiment further includes adjusting the incident angle θ, so that when the object to be measured is displaced within the adjusted measurement range, the positions of the two reflected light spots on the photosensitive surface of the area array image sensor 300 do not exceed the boundary of the photosensitive surface.
According to the laser ranging method and the laser range finder provided by the embodiment of the invention, a single measuring laser beam is changed into a double beam, and two beams of laser are projected on the surface of a measured object, so that two reflected light spots are formed on the area array image sensor 300, when the measured object moves, the actual displacement of the measured object is further obtained by obtaining the difference relative position of the two reflected light spots, and the mode can improve the anti-interference performance of the area array image sensor 300 by increasing the number of measuring points, thereby improving the measuring precision.
It is to be understood that the above-described embodiments are merely illustrative of some, but not restrictive, of the broad invention, and that the appended drawings illustrate preferred embodiments of the invention without limiting its scope. This invention may be embodied in many different forms and, on the contrary, these embodiments are provided so that this disclosure will be thorough and complete. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and modifications can be made, and equivalents may be substituted for elements thereof. All equivalent structures made by using the contents of the specification and the attached drawings of the invention can be directly or indirectly applied to other related technical fields, and are also within the protection scope of the patent of the invention.
Claims (11)
1. A laser ranging method, comprising:
irradiating a first laser beam and a second laser beam to the surface of a measured object at a certain incident angle theta, wherein the first laser beam and the second laser beam are reflected by the surface of the measured object and form two reflection light spots on a photosensitive surface of an area array image sensor after being scaled by the multiplying power of an optical receiving assembly, the incident angle theta is a preset constant, the first laser beam can be coincided with the second laser beam when rotating along a specific rotating shaft for a certain angle, and the rotating shaft is perpendicular to the surface of the measured object;
acquiring position coordinates of the two reflection light spots on the photosensitive surface, and obtaining the relative distance d1 of the two reflection light spots according to the position coordinates;
when the measured object is displaced in the axial direction of the rotating shaft, the positions of the two reflected light spots on the photosensitive surface of the area array image sensor are correspondingly changed, the position coordinates of the two reflected light spots on the photosensitive surface after the measured object is displaced are obtained, and the relative distance d2 of the two reflected light spots is obtained according to the changed position coordinates;
and acquiring the displacement of the measured object in the axial direction of the rotating shaft according to the incident angle theta and the relative distance d1 and d 2.
2. The method according to claim 1, wherein when the object to be measured is displaced in the axial direction of the rotating shaft, the two reflected light spots have no overlapping of the light spot movement tracks on the photosensitive surface of the area array image sensor and are parallel to each other.
3. Method according to claim 1, characterized in that said first and second laser beams, respectively, of incidence angle θ are generated by two laser emitters, or
And emitting a laser beam by a laser emitter, and forming the first laser beam and the second laser beam with an incidence angle theta by a light splitting device.
4. The method of claim 1, further comprising:
and adjusting the relative position and angle of the area array image sensor and the optical receiving component so as to adjust the measuring range of the laser measuring instrument.
5. The method of claim 4, further comprising:
and adjusting the incident angle theta to ensure that the positions of the two reflection light spots on the photosensitive surface of the area array image sensor do not exceed the boundary of the photosensitive surface when the measured object displaces within the adjusted measuring range.
6. The method of claim 1, wherein after the object under test is displaced in the axial direction of the rotating shaft, the method further comprises:
and acquiring the moving distances of the two reflected light spots on the photosensitive surface of the area array image sensor, and correcting the relative distance of the two reflected light spots according to the moving distances of the two reflected light spots when the absolute value of the difference of the moving distances of the two reflected light spots is larger than a preset threshold value, otherwise, not correcting the relative distance of the two reflected light spots.
7. A laser range finder is characterized by comprising a laser emitting device, an optical receiving component, an area array image sensor and a processing unit, wherein the laser emitting device, the area array image sensor and the optical receiving component are sequentially arranged from top to bottom, and the area array image sensor is electrically connected with the processing unit;
the laser emitting device is used for emitting a first laser beam and a second laser beam, and the first laser beam and the second laser beam are enabled to irradiate the surface of a measured object at a certain incident angle;
the optical receiving assembly is used for transmitting the first laser beam and the second laser beam to a photosensitive surface of the area array image sensor after multiplying power scaling is carried out on the laser reflected by the surface of the measured object, and two reflected light spots are formed on the photosensitive surface;
the processing unit is used for acquiring the relative distance between the two reflection light spots before and after the measured object moves along the axial direction of the rotating shaft, and acquiring the displacement of the measured object according to the incident angle and the relative distance between the two reflection light spots before and after the measured object moves.
8. The laser range finder of claim 7, wherein the laser emitting device comprises two laser emitters for emitting a first laser beam and a second laser beam, such that the first laser beam and the second laser beam irradiate onto the surface of the object to be measured at a certain incident angle.
9. The laser range finder of claim 7, wherein the laser emitting device comprises a laser emitter and a beam splitting device sequentially arranged from top to bottom, and the beam splitting device is configured to split laser emitted by the laser emitter to form a first laser beam and a second laser beam, and to irradiate the first laser beam and the second laser beam onto a surface of an object to be measured at a certain incident angle.
10. The laser range finder of claim 8 or 9, wherein the size of the light sensitive surface of the area array image sensor is adapted to the zoom ratio of the optical receiving component.
11. The laser range finder of claim 8 or 9, wherein the area array image sensor is disposed in a non-perpendicular manner to the optical receiving assembly.
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| CN110081819A (en) * | 2019-04-30 | 2019-08-02 | 湖北三江航天万峰科技发展有限公司 | The high frequency position measuring device and method of moving object in a kind of pipeline |
| CN110132374B (en) * | 2019-05-20 | 2020-07-31 | 哈尔滨理工大学 | Self-compensating laser liquid level measuring system |
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| TWI735337B (en) * | 2020-09-11 | 2021-08-01 | 由田新技股份有限公司 | Linear displacement calibration method and inspection apparatus using the same |
| CN112748439A (en) * | 2020-12-01 | 2021-05-04 | 南京理工大学北方研究院 | Laser online distance measurement detection method based on cloud computing service |
| CN113050107B (en) * | 2021-03-11 | 2021-11-02 | 广州市合熠智能科技股份有限公司 | High-precision intelligent distance measuring system of laser displacement sensor |
| CN116068567B (en) * | 2023-04-07 | 2023-06-13 | 天津宜科自动化股份有限公司 | Ranging system based on laser triangular ranging sensor |
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Effective date of registration: 20231117 Address after: 518000 Building 401, Building 4, Chongqing Road, Han's Laser Industrial Park, Heping Community, Fuyong Street, Bao'an District, Shenzhen City, Guangdong Province Patentee after: SHENZHEN HAN'S SCANNER S&T Co.,Ltd. Address before: 518000 9 new West Road, North Nanshan District high tech park, Shenzhen, Guangdong Patentee before: HAN'S LASER TECHNOLOGY INDUSTRY GROUP Co.,Ltd. Patentee before: SHENZHEN HAN'S SCANNER S&T Co.,Ltd. |