CN120684981A - Multi-point laser ranging device and ranging method - Google Patents
Multi-point laser ranging device and ranging methodInfo
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- CN120684981A CN120684981A CN202510812578.5A CN202510812578A CN120684981A CN 120684981 A CN120684981 A CN 120684981A CN 202510812578 A CN202510812578 A CN 202510812578A CN 120684981 A CN120684981 A CN 120684981A
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- beam splitter
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- imaging lens
- photosensitive surface
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Abstract
本发明公开了一种多点激光测距装置及测距方法，属于激光测距技术领域。本发明包括激光器、光束分束器、成像透镜和光敏面，激光器出射的激光垂直于光束分束器入射；光束分束器、成像透镜及光敏面三者平行设置，光敏面设于成像透镜的焦距f′处。本发明通过光束分束器将一束激光分成多个光束，同时打到待测物体上，利用CMOS/CCD工业相机采集射到待测物体上的光点图像，测量成像光点到透镜光轴的距离，间接计算得到待测物体测量点到光束分束器的距离，从而实现了一次测量即可测到物体上多个位置的距离，显著提高了激光测距的效率，降低了成本，拓展了激光测距的应用领域。
The present invention discloses a multi-point laser ranging device and ranging method, belonging to the field of laser ranging technology. The present invention comprises a laser, a beam splitter, an imaging lens, and a photosensitive surface. The laser light emitted by the laser is incident perpendicularly to the beam splitter; the beam splitter, the imaging lens, and the photosensitive surface are arranged in parallel, and the photosensitive surface is arranged at the focal length f' of the imaging lens. The present invention splits a laser beam into multiple beams by a beam splitter, and simultaneously projects them onto an object to be measured. A CMOS/CCD industrial camera is used to capture an image of the light spot projected onto the object to be measured, and the distance from the imaging light spot to the optical axis of the lens is measured. The distance from the measuring point of the object to be measured to the beam splitter is indirectly calculated, thereby achieving the goal of measuring the distances of multiple positions on the object in one measurement, significantly improving the efficiency of laser ranging, reducing costs, and expanding the application field of laser ranging.
Description
Technical Field
The invention belongs to the technical field of laser ranging, and particularly relates to a multi-point laser ranging device and a ranging method.
Background
The laser ranging technology is widely applied to the fields of engineering mapping, target positioning, automatic driving and the like by virtue of the advantages of non-contact, high precision, high speed and the like. In the engineering mapping field, the laser ranging can efficiently acquire the accurate data of the topography and the land feature, and the assistance drawing of a high-precision map provides basic data support for city planning, road construction and the like. In the aspect of target positioning, the laser ranging plays an indispensable role in accurately locking targets in military and accurately calibrating the positions of parts in industrial production. In the field of automatic driving, laser ranging is one of core sensing technologies, and helps vehicles to sense the distance and the position of objects in the surrounding environment in real time, so that key information is provided for automatic driving decision.
The triangular ranging method is an important class in the laser ranging technology and has a unique working mechanism. The principle is based on the specific relative position relation of the emitter and the receiver, and the two and the reflection point jointly construct a triangle structure. Specifically, the laser beam emitted by the emitter is emitted to the surface of the measured object at a specific angle, the surface of the object reflects the laser, and the reflected light is captured by the receiver. By measuring the position of the reflection point in the receiver, the distance between the measured object and the measuring device can be accurately calculated by means of geometric relations such as trigonometric functions. The method has relatively low requirements on hardware, is relatively controllable in cost, can keep higher precision in a close-range measurement scene, and is widely applied in a close-range detection scene.
However, the existing laser triangulation ranging technology also has certain limitations. In practice, the transmitter can only emit one laser beam in a single operation, which means that it can only measure the distance of one point on the object in one measurement. The problem is highlighted when faced with the task of detecting the surface of a large object and acquiring positional information of multiple points. On the one hand, if a mode of multiple measurement is adopted, that is, the transmitter sequentially measures the points at different positions, the time required for measurement is obviously increased, the whole measurement process becomes tedious one by one, and the production efficiency is seriously affected. On the other hand, using multiple rangefinders to measure different locations simultaneously can improve efficiency to some extent, but can add significant cost. Not only does the purchase of multiple rangefinders require more capital investment, but subsequent maintenance, calibration, etc. also can result in additional cost. For example, in some large industrial production lines, if multiple key parts of a large-scale device are to be monitored in real time, deployment of multiple rangefinders can greatly increase the front-end equipment investment and the back-end operation cost of an enterprise.
Disclosure of Invention
Aiming at the problems of low efficiency and high cost of the conventional laser triangulation ranging in the background technology when facing the multi-point measurement requirement, the invention provides a multi-point laser ranging device and a ranging method, which are characterized in that a beam splitter is introduced to divide a beam of laser into a plurality of beams, the plurality of beams are simultaneously beaten on an object to be measured, a CMOS/CCD industrial camera is utilized to collect light spot images on the object to be measured, and the distance between an imaging light spot on a photosensitive surface and a lens optical axis is measured to indirectly calculate and obtain the distance between the measuring point of the object to be measured and the surface of the beam splitter, so that the distance between a plurality of positions on the object can be measured by one-time measurement, the efficiency of laser ranging is obviously improved, the cost is reduced, and the application field of laser ranging is expanded.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
The invention relates to a multi-point laser ranging device, which comprises a laser, a beam splitter, an imaging lens and a photosensitive surface, wherein:
the laser is arranged perpendicular to the surface of the beam splitter, so that the laser emitted by the laser can be incident perpendicular to the surface of the beam splitter;
the beam splitter is arranged in parallel with the imaging lens, the photosensitive surface is arranged in parallel with the imaging lens, and the distance from the incident point A of the beam splitter to the optical axis O of the imaging lens is denoted as AO;
The photosurface is arranged in parallel with the imaging lens, the optical axis of the imaging lens is perpendicular to the photosurface and intersects with the photosurface at a point M, and the photosurface is positioned at a focal length f' of the imaging lens.
Furthermore, the diffraction angle corresponding to the beam splitter light spot is recorded as alpha i,αi, and the value range is 0 degrees less than or equal to alpha i degrees <90 degrees.
Further, the beam splitter adopts a Dammann (Dammann) grating beam splitter.
Furthermore, the AO value range is 10mm ~200mm.
Further, the photosurface adopts a CCD/CMOS camera photosurface.
Further, two polarizers are arranged between the laser and the beam splitter.
The invention relates to a multipoint laser ranging method, which adopts the laser ranging device to measure, and specifically comprises the following steps:
s1, emitting point laser by a laser, irradiating the point laser onto an object to be detected through a beam splitter, and imaging a light point which is incident onto the object to be detected on a photosensitive surface through an imaging lens;
Step S2, calculating the distances from different positions of the object to the surface of the beam splitter by adopting the following formula:
Where l i is the distance between any one light spot on the object and the beam splitter, AO is the distance between the incident point a of the beam splitter and the optical axis of the imaging lens, f' is the focal length of the imaging lens, d i is the distance between the image point M i on the photosensitive surface and the reference point M, M is the intersection point of the optical axis of the imaging lens and the photosensitive surface, where the upper part of the zero-order diffraction is defined as positive and the lower part of the zero-order diffraction is defined as negative.
Compared with the prior art, the invention has the beneficial effects that:
According to the multipoint laser ranging device, the structure of the device is optimally designed, and the beam splitter is arranged to be matched with the imaging lens and the optical camera, so that the distance between a plurality of positions on an object can be measured at one time, the laser ranging efficiency is remarkably improved, the cost is reduced, the application field of laser ranging is expanded, and the measuring device is simple in structure and convenient to install and use.
In addition, the invention uses the optical camera to collect and image, and through designing the calculation formula of l i, the automatic ranging and calculation can be realized through programming, thereby remarkably improving the working efficiency of laser multipoint ranging.
Drawings
Fig. 1 is a schematic structural diagram of a multipoint ranging device according to the present invention.
In the figure:
1.2, a beam splitter, 3, an imaging lens, 4, a photosensitive surface.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
Referring to fig. 1, the multi-point laser ranging device of the present embodiment includes a laser 1, a beam splitter 2, an imaging lens 3 and a photosensitive surface 4, where the laser 1 is disposed perpendicular to the surface of the beam splitter 2, so that the laser emitted by the laser 1 can be incident perpendicular to the surface of the beam splitter 2, and each light spot split by the beam splitter 2 is distributed on a straight line, and in practical use, the light spot split can be ensured to be distributed horizontally or vertically by modulating the azimuth of the beam splitter 2. The beam splitter 2 and the imaging lens 3 are arranged in parallel, and the distance from the incidence point a of the beam splitter 2 to the optical axis O of the imaging lens 3 is denoted AO. The photosurface 4 is arranged in parallel with the imaging lens 3, and the photosurface 4 is arranged at the focal length f' of the imaging lens 3.
The ranging device of this embodiment places according to the light path structure, and the advantage of this structure is compact, and occupation space is little, and the assembly of being convenient for adopts beam splitter 2 can divide into the even multi-beam laser of intensity with a beam laser beam, shines on the object surface that awaits measuring to realize the purpose of multiple spot range finding. Specifically, the dammann grating beam splitter is adopted in the embodiment, the working principle of the dammann grating beam splitter is based on light diffraction, the incident light beam can be divided into a plurality of light spots on a straight line by etching a periodic structure on the surface of glass and modulating the wave front phase of the incident wave, and the beam splitter is characterized in that the intensity of each light spot after beam splitting is uniform, and the beam splitting point and the diffraction angle can be controlled. In the actual measurement process, the diffraction angle of the split light rays relative to the central light rays is fixed, the diffraction angle alpha i can be changed by changing the grating constant, the value range of the diffraction angle alpha i is 0 degrees less than or equal to alpha i degrees and less than 90 degrees, and in the actual measurement process, if the position of a measurement point needs to be changed, the position of the measurement point can be changed, and the distance between a measurement object and the beam splitter 2 can be changed or the beam splitter 2 can be changed.
As a further improvement of the present embodiment, the applicant found that the AO value is related to the size of the photosurface, the measurement distance and the diffraction angle, and that the maximum value of the AO value can be calculated according to the following formula when designing:
Wherein l is the measurement distance, w is the length of the photosensitive surface, f' is the focal length of the imaging lens 3, α max is the maximum diffraction angle, and the AO value range in this embodiment is preferably 10 mm-200 mm in consideration of the specific situation and the compactness of the ranging device structure.
The photosensitive surface 4 in this embodiment adopts a CCD/CMOS camera photosensitive surface, and the method for performing multipoint ranging by adopting the device is as follows:
and S1, fixing after the erection of the distance measuring device is completed, selecting the focal length of the imaging lens 3, measuring the distance of AO, and selecting the diffraction angle of the beam splitter.
Step S2, the laser 1 emits a beam of laser light to be incident on the surface of the beam splitter 2, the beam splitter splits the light into three beams, and the upper beam and the lower beam of the beam are symmetrical about a central beam. The three beams of light are incident on the surface of the object at different positions N- 1、N0 and N +1, and the distances from the beam splitter are l- 1、l0 and l +1 respectively. Three light spots N- 1、N0 and N +1 which are incident on the object are imaged on the photosensitive surface 4 of the CCD/CMOS camera through the imaging lens 3 at the points M- 1、M0 and M +1 respectively, wherein the point M is the intersection point of the optical axis of the imaging lens 3 and the photosensitive surface 4.
Assuming that the pixel size of the CCD/CMOS camera is x, the pixel numbers from M- 1、M0 and M +1 to M are respectively obtained by using an image processing technology and are recorded as M i, i= -1,0 and +1, and the distance d i from M to M between M- 1、M0 and M +1 can be calculated according to a formula d i＝x×mi.
Then, the distance l i between the object to be measured and the center of the beam splitter 2 is calculated according to the following calculation formula:
Where l i is the distance from any one light spot on the object to the center of the beam splitter 2, AO is the distance between the incident point a of the beam splitter 2 and the optical axis of the imaging lens 3, f' is the focal length of the imaging lens 3, d i is the distance from the image point M i on the photosurface 4 to the reference point M, and the point M is the intersection point of the optical axis of the imaging lens 3 and the photosurface 4.
The specific values of the parameters in this embodiment are set as follows:
ao=60 mm, diffraction angle α ±1＝0.963°,f′＝16mm,d-1＝1.181mm,d0＝0.906mm,d1 =0.630 mm;
L- 1＝1052.4mm,l0＝1059.6mm,l1 = 1068.1mm calculated using the above formula.
It should be noted that, the above formula uses the diffraction angle of the beam splitter 2, and the existing measurement method based on the triangulation method, whether the measurement method is direct-injection type or oblique-injection type, is substantially different from the method of the present invention, for example, the oblique-injection type, and the actual distance can be calculated only by using the data of the reference plane. The formula provided by the invention does not need a reference plane, is convenient to use and simpler, and can be realized according to the prior art.
The technical scheme of the invention effectively solves the problem that the laser ranging can measure the distances of a plurality of positions of an object at one time, and the measuring device has simple structure and convenient installation and use.
Example 2
The multi-point laser ranging device of the embodiment is basically the same as the embodiment 1 in structure, and is different from the embodiment 1 in that two polarizers are arranged between the laser 1 and the beam splitter 2, the first polarizer is used for converting light emitted by the laser 1 into linearly polarized light, and the intensity of the emitted light after the beam splitter 2 can be changed by rotating the second polarizer, so that the measuring use under different environments is satisfied.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202510812578.5A CN120684981A (en) | 2025-06-18 | 2025-06-18 | Multi-point laser ranging device and ranging method |
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| CN202510812578.5A CN120684981A (en) | 2025-06-18 | 2025-06-18 | Multi-point laser ranging device and ranging method |
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