CN117405041A - Laser three-dimensional scanning measuring equipment - Google Patents

Abstract

The disclosure describes a laser three-dimensional scanning measuring equipment, including the base, set up in the base and use first axis as the rotation axis first rotating part that rotates, set up in first rotating part and use the second axis that is orthogonal with first axis as the rotation axis and rotate the second rotating part, and set up in the second rotating part and with the beam deflection main part of second rotating part linkage, the beam deflection main part is including the measurement interferometer that is configured to produce the measurement interference signal based on measuring beam, the base is provided with the optic fibre optical path system, the optic fibre optical path system includes the frequency modulation laser source, the detection subassembly, the measurement interferometer is connected through polarization maintaining optical fiber with the frequency modulation laser source, polarization maintaining optical fiber passes through the base in proper order, first rotating part and second rotating part are in order with guiding measuring beam to the measurement interferometer. Thus, a laser three-dimensional scanning measurement device capable of improving the degree of weight reduction of the device, the compactness of the structure, and the anti-interference performance of the measurement accuracy can be provided.

Description

Laser three-dimensional scanning measuring equipment

Technical Field

The present disclosure relates generally to the field of intelligent manufacturing equipment industry, and in particular to a laser three-dimensional scanning measurement device.

Background

With the development of technology, high-precision detection of three-dimensional coordinates of large-size workpieces is more and more frequent, and the existing equipment for detecting the large-size workpieces mainly comprises three-coordinate machine measuring equipment, theodolite measuring equipment, a laser tracker, vision measuring equipment and the like. These devices have the disadvantage of low working efficiency, the need to paste the mark points or use the reflective target sphere to measure, and so on, and therefore, in some cases, the high efficiency and high accuracy detection required by the user cannot be satisfied. The laser radar technology has the characteristics of simple ranging and speed measuring algorithm, low power requirement on a transmitter, no distance blind area in echo signals, capability of obtaining higher distance resolution and speed resolution, and the like, so that the laser radar technology can well solve the problems to better detect large-size workpieces.

The existing lidar device generally has a dual-axis turntable (i.e. a moving platform) with functions of pitching rotation and horizontal rotation, wherein the deflection of an optical path in the pitching direction is generally realized by adopting a reflector mode, namely, an optical path system is completely installed and placed on a base, and a measuring beam and an indicating beam are emitted vertically upwards after passing through a focusing assembly and finally are focused on the surface of a sample for measurement through the reflection of a rotating reflector on the pitching axis. The laser radar equipment can realize the separation of the optical path system and the moving platform, so that the influence of vibration of the moving platform on the optical path can be reduced, interference in measurement can be reduced, and meanwhile, the optical path system can be independently subjected to sealing protection or constant temperature and humidity control, so that the influence of environmental change on the optical path system is reduced.

However, in the above prior art, since the laser radar apparatus adopts the mirror mode to perform optical path refraction or reflection (i.e. guide the light beam), and the polarization maintaining effect of the mirror directly affects the stability and the signal to noise ratio of the measurement signal, the whole optical path system needs to perform polarization maintaining, i.e. the mirror needs to be ensured to implement polarization maintaining reflection in a large angle range, which has very high processing requirements on the mirror, and the supply chain is difficult to achieve such processing requirements. In addition, placing the entire optical path system, focusing assembly, etc. in the base can make the base of the lidar device bulky, heavy and not compact in structure, and there are many inconveniences in operating the lidar device.

Disclosure of Invention

The present disclosure has been made in view of the above-described conventional circumstances, and an object thereof is to provide a laser three-dimensional scanning measurement device capable of improving the degree of weight reduction of the device, the compactness of the structure, and the interference resistance of the measurement accuracy.

To this end, the present disclosure provides a laser three-dimensional scanning measurement apparatus, which is an apparatus for detecting a distance of a target based on a laser radar principle, including a base, a first rotating part provided to the base and rotated about a first axis as a rotation axis, a second rotating part provided to the first rotating part and rotated about a second axis orthogonal to the first axis as a rotation axis, and a beam deflecting body provided to the second rotating part and linked with the second rotating part, the beam deflecting body including a measurement interferometer configured to generate a measurement interference signal based on a measurement beam, the base being provided with an optical fiber optical path system including a frequency modulation laser light source for generating a linear frequency modulation laser as the measurement beam, and a detection assembly configured to receive the measurement interference signal to obtain the distance of the target, the measurement interferometer being connected to the frequency modulation laser light source through a polarization maintaining fiber passing through the base, the first rotating part, and the second rotating part in order to guide the measurement beam to the measurement interferometer.

In the present disclosure, a frequency modulation laser light source is disposed on a base, a laser beam emitted by the frequency modulation laser light source propagates through a polarization maintaining fiber in an optical fiber optical path system to obtain a measuring beam, the measuring beam is guided from the base to a measuring interferometer disposed on a beam deflection main body of a second rotating portion, and a measuring interference signal of the measuring interferometer is guided back to a detection component in the base through the polarization maintaining fiber, thereby forming an optical fiber optical path. Under the condition, the optical fiber path can replace the existing mirror type optical path scheme to guide the measuring beam so as to conveniently finish the measuring work, namely, the higher processing requirement on the mirror in the mirror type optical path scheme can be reduced; in addition, compared with the existing mirror type optical path scheme, the optical beam deflection main body arranged on the second rotating part has higher adaptability to space, for example, a frequency modulation laser light source is arranged on the base, the measuring interferometer, the focusing device and the overview camera are arranged on the optical beam deflection main body, and the defects that the existing mirror type optical path scheme has the structures such as an optical fiber optical path system, the measuring interferometer, the focusing device and the overview camera device on the base, and the like, causes the structural redundancy and the bulk of the base, and the like are avoided, so that the structural arrangement of the laser three-dimensional scanning measuring equipment can be optimized conveniently, and the light weight degree and the structural compactness of the laser three-dimensional scanning measuring equipment are improved; in addition, based on the characteristic of the Fabry-Perot interferometer structure, errors caused by the fact that a polarization maintaining optical fiber is used between the base and the light beam deflection main body can be reduced. Specifically, the measurement interferometer can form a common mode signal by the measurement signal and the local oscillation signal so as to reduce the influence of vibration, optical fiber pulling, temperature change and other factors on the measurement precision when the equipment rotates in a differential mode, namely the measurement anti-interference performance can be improved, and the measurement precision is improved.

In addition, according to the laser three-dimensional scanning measurement device to which the present disclosure relates, optionally, the beam deflecting body further includes a focusing device located between the measurement interferometer and the target, the focusing device being configured to focus the measurement beam to the target. In this case, the spot size of the measuring beam can be compressed by the focusing means such that the measuring beam is focused onto one spot of the target (the size of the focal spot depends on the size of the focal spot, which is distance-dependent, from a few meters to tens of meters, and the focal spot size can be from tens of micrometers to a few millimeters). This makes it possible to make the signal of the light reflected by the object stronger, and at the same time to make the lateral resolution of the measurement higher, and the measurement distance stability higher.

In addition, according to the laser three-dimensional scanning measurement apparatus related to the present disclosure, optionally, the beam deflecting body further includes an overview camera device configured to acquire an image of the target, an optical axis of the overview camera device being disposed coaxially with the measurement beam. In this case, it is possible to locate the target by the image of the target, and to perform beam deflection control according to the coordinates of the image and to make a measurement plan according to the image to achieve rapid measurement of the region.

In addition, according to the laser three-dimensional scanning measurement device related to the disclosure, optionally, the base is further provided with a temperature control structure, the temperature control structure is used for improving environmental stability of the optical fiber optical path system, and at least a part of polarization maintaining optical fiber is located in the temperature control structure. In this case, temperature adjustment of the base and the polarization maintaining fiber can be achieved, whereby constant temperature operation of the polarization maintaining fiber and the fiber optical path system can be achieved to improve measurement accuracy.

In addition, according to the laser three-dimensional scanning measurement apparatus related to the present disclosure, optionally, the base and the first rotating portion are rotatably connected by a first rotating mechanism, the first axis is a central axis of the first rotating mechanism, and a polarization maintaining fiber guides the measurement beam from the base to the beam deflecting body along the first axis. In this case, the base and the first rotating portion can be made to rotate with each other while guiding the measuring beam from the base to the beam deflecting body by the polarization maintaining optical fiber, whereby the laser three-dimensional scanning measuring apparatus can be facilitated to perform tracking measurement of the target with the first axis as the rotation axis, for example, to drive the first rotating portion to rotate in the horizontal direction to track the target.

In addition, according to the laser three-dimensional scanning measurement apparatus related to the present disclosure, optionally, the first rotating portion and the second rotating portion are rotatably connected by a second rotating mechanism, the second axis is a central axis of the second rotating mechanism, and a polarization maintaining fiber guides the measurement beam from the first rotating portion to the measurement interferometer located at the second rotating portion along the second axis. In this case, the first rotating portion and the second rotating portion can be made to rotate with each other while guiding the measuring beam from the base to the measuring interferometer by the polarization maintaining optical fiber, whereby the laser three-dimensional scanning measuring apparatus can be facilitated to perform tracking measurement on the target with the second axis as the rotation axis, for example, the second rotating portion is driven to rotate in the vertical direction to track the target.

In addition, according to the laser three-dimensional scanning measurement apparatus related to the present disclosure, optionally, the first rotation mechanism includes a first angle measurement device for acquiring a first deflection angle of the target, and the second rotation mechanism includes a second angle measurement device for acquiring a second deflection angle of the target. In this case, it is possible to accurately track the target by obtaining the first deflection angle and the second deflection angle of the target.

In addition, according to the laser three-dimensional scanning measurement device related to the disclosure, optionally, the first rotation part is in a symmetrical shape and has a concave part in the middle, the second rotation part is located in the concave part, and the first axis coincides with a symmetry line of the first rotation part. In this case, the laser three-dimensional scanning measurement apparatus can be made to have a better balance.

Additionally, according to a laser three-dimensional scanning measurement device to which the present disclosure relates, optionally, the measurement interferometer includes a partially reflecting component configured to receive the measurement beam and split the measurement beam into a first beam transmitted to the target via the partially reflecting component and reflected by the target to form a first reflected beam, a polarizing module configured to adjust a polarization state of the measurement beam, and a collimating module cooperating with the partially reflecting component and configured to collimate the measurement beam; the detection assembly is further configured to obtain a distance between the partially reflective assembly and the target based on interference results of the first reflected light beam and the second light beam. In this case, the measuring beam is transmitted through the partial reflection assembly to obtain a first beam and reflected by the target to obtain a first reflected beam, and is directly reflected by the partial reflection assembly to obtain a second beam, so that the first reflected beam and the second beam share one optical fiber path, that is, the partial reflection assembly and the target can form a "fabry-perot" interferometer structure so that the first reflected beam and the second beam interfere in one optical fiber path, thereby obtaining the distance of the target according to the interference result of the first reflected beam and the second beam; in addition, after the first light beam (or the first reflected light beam) and the second light beam in the measuring light beam are adjusted by the polarization module, the first light beam and the second light beam are respectively converted into polarized light beams with specific polarization states, for example, the first light beam with linear polarization is converted into circularly polarized light or elliptically polarized light, or vice versa, so that the independence and the stability of the first light beam and the second light beam in the measuring light beam can be improved, the transmission quality or the signal-to-noise ratio of the first light beam and the second light beam in the optical fiber light path can be improved, and the detection assembly can detect the first reflected light beam and the second light beam more accurately; in addition, after the measuring beam is collimated by the collimating module, the divergence degree of the measuring beam can be reduced to enable the measuring beam to be collimated (parallel light), so that the beam quality of the measuring beam incident on the partial reflecting assembly can be improved.

In addition, according to the laser three-dimensional scanning measurement device related to the disclosure, optionally, the optical fiber optical path system further comprises an auxiliary interferometer, an optical fiber coupling component and an indication light source, wherein the frequency modulation laser light source, the detection component, the auxiliary interferometer, the optical fiber coupling component and the indication light source are connected through polarization maintaining optical fibers; the auxiliary interferometer generates an auxiliary measurement signal based on the measurement beam to achieve nonlinear correction of the frequency modulated laser light source; the optical fiber coupling assembly is configured to realize beam splitting or beam combination of the measuring light beam; the indication light source is used for generating an indication light beam to indicate the target, and the indication light beam is guided by the polarization maintaining fiber and coupled to the fiber optical path system by the fiber coupling component. In this case, the frequency modulation linearity of the measurement laser can be improved by performing nonlinear correction on the frequency modulation laser light source by the auxiliary interferometer, thereby improving the accuracy of measurement; in addition, the optical fiber coupling assembly can better guide the measuring beam or the indicating beam into a specific assembly, for example, an auxiliary interferometer which can facilitate the subsequent arrangement after the measuring beam is split by the optical fiber coupling assembly can detect and correct the measuring beam, for example, the optical fiber coupling assembly can synchronize the indicating beam and the measuring beam in one optical path after the measuring beam and the indicating beam (namely the auxiliary beam) are combined, so that whether the measuring beam is aligned with a target can be conveniently distinguished by the indicating beam; in addition, in the case of an indicator beam, the indicator beam is coupled with the measuring beam through the fiber coupling assembly to the fiber optic system, in particular to a polarization maintaining fiber in the fiber optic system, and is directed to the beam deflecting body together with the measuring beam, the indicator beam can also be focused to the target by the focusing device for assisting in discriminating whether the measuring beam is aimed at the target or focused to the target.

According to the present disclosure, a laser three-dimensional scanning measurement apparatus capable of improving the degree of weight reduction of the apparatus, the compactness of the structure, and the interference resistance of the measurement accuracy can be provided.

Drawings

Embodiments of the present disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings.

Fig. 1 is a schematic view showing an application scenario of a laser three-dimensional scanning measurement apparatus for detecting a target according to an example of the present disclosure.

Fig. 2 is a schematic diagram showing the structure of a laser three-dimensional scanning measurement apparatus according to an example of the present disclosure.

Fig. 3 is a block diagram showing a first embodiment of an optical fiber path system in a laser three-dimensional scanning measurement apparatus according to an example of the present disclosure.

Fig. 4 is a block diagram showing a second embodiment of a fiber optic path system in a laser three-dimensional scanning measurement apparatus according to an example of the present disclosure.

Fig. 5 is a block diagram showing a structure of a beam deflection body in a laser three-dimensional scanning measurement apparatus according to an example of the present disclosure.

Fig. 6 is a block diagram showing a structure of a measurement interferometer in a laser three-dimensional scanning measurement apparatus according to an example of the present disclosure.

Fig. 7 is a schematic diagram showing the operation principle of the laser three-dimensional scanning measurement apparatus of the first embodiment according to the example of the present disclosure.

Fig. 8 is a schematic diagram showing the operation principle of a laser three-dimensional scanning measurement apparatus of a second embodiment according to an example of the present disclosure.

Fig. 9 is a schematic diagram showing the operation principle of a laser three-dimensional scanning measurement apparatus of a third embodiment according to an example of the present disclosure.

Reference numerals illustrate:

a laser three-dimensional scanning measuring apparatus, 11 first rotating part, 12 second rotating part, 13 base, 14 beam deflection main body, 15 optical fiber optical path system, 16 temperature control structure, Z first axis, X second axis, 110 first rotating mechanism, 111 first driving motor, 112 first fixed bearing, 113 first rotating shaft, 114 first angle measuring device, 120 second rotating mechanism, 121 second driving motor, 122 second fixed bearing, 123 second rotating shaft, 124 second angle measuring device, 151 FM laser light source, 141 measuring interferometer, 152 detection component, 154 optical fiber coupling component, F-P "Fabry-Perot" interferometer structure, 1411 collimation module, 1412 polarization module, 1413 partial reflection component, 1541 polarization maintaining optical fiber polarization, 1542 polarization maintaining optical fiber wavelength division multiplexer, 1543 polarization maintaining optical fiber circulator, 1544 polarization maintaining optical fiber isolator, 142 focusing device, 143 overview camera device, 1431 reflector, 1432 overview camera, 1433 image processing circuit, 153 auxiliary interferometer,

2 … target.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same members are denoted by the same reference numerals, and overlapping description thereof is omitted. In addition, the drawings are schematic, and the ratio of the sizes of the components to each other, the shapes of the components, and the like may be different from actual ones.

It should be noted that the terms "comprises" and "comprising," and any variations thereof, in this disclosure, such as a process, method, system, article, or apparatus that comprises or has a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus, but may include or have other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 1 is a schematic view showing an application scenario of a laser three-dimensional scanning measurement apparatus 1 for detecting a target 2 according to an example of the present disclosure. Fig. 2 is a schematic diagram showing the structure of a laser three-dimensional scanning measurement apparatus 1 according to an example of the present disclosure. Fig. 3 is a block diagram showing the structure of a first embodiment of the optical fiber optical path system 15 in the laser three-dimensional scanning measurement apparatus 1 according to the example of the present disclosure. Fig. 4 is a block diagram showing a configuration of a second embodiment of the optical fiber optical path system 15 in the laser three-dimensional scanning measurement apparatus 1 according to the example of the present disclosure. Fig. 5 is a block diagram showing the structure of the beam deflecting body 14 in the laser three-dimensional scanning measurement apparatus 1 according to the example of the present disclosure. Fig. 6 is a block diagram showing the structure of a measurement interferometer 141 in the laser three-dimensional scanning measurement apparatus 1 according to the example of the present disclosure.

As shown in fig. 1, the present disclosure provides a laser three-dimensional scanning measurement apparatus 1, which is a laser three-dimensional scanning measurement apparatus 1 for detecting a distance of a target 2, and particularly, refers to a laser three-dimensional scanning measurement apparatus 1 for detecting a distance of a target 2 based on an operation principle of a laser radar.

The laser three-dimensional scanning measurement apparatus 1 according to the present disclosure achieves light weight and compact structure by adopting an optical fiber path, and the measurement accuracy is not easily disturbed by the environment.

The laser three-dimensional scanning measurement apparatus 1 to which the present disclosure relates may also be referred to as "laser three-dimensional scanning measurement apparatus 1 having an optical fiber path", "direct laser three-dimensional scanning measurement apparatus 1", "direct laser measurement device", "laser three-dimensional scanning measurement apparatus 1 having a plurality of movement axes", or "tracking laser three-dimensional scanning measurement apparatus 1", or the like.

In some examples, a "fiber optic path" is an optical path that uses an optical fiber or fiber assembly to form a beam path that can guide a measuring beam. In some examples, "direct-lit" may refer to the measurement beam being emitted directly from the moving platform (e.g., the second rotating portion 12 to which the present disclosure relates) of the laser three-dimensional scanning measurement device 1 to reach the target 2 without the need to reflect the measurement beam from the laser light source (e.g., the base or pedestal 13) through a mirror on the moving platform as in the case of "mirror" to reach the target 2.

In some examples, the laser three-dimensional scanning measurement device 1 detecting the distance of the target 2 may refer to acquiring the distance of the target 2 and acquiring the azimuth, altitude, speed, attitude, even shape, etc. of the target 2 based on the distance.

In some examples, the laser three-dimensional scanning measurement apparatus 1 to which the present disclosure relates may particularly refer to a laser radar device, which is a radar device that detects a characteristic amount of a position, a speed, or the like of the target 2 with an emitted laser beam. The laser radar device operates on the principle that a detection signal (i.e., a measuring beam) is emitted to the target 2, and then a received signal (i.e., a reflected beam) reflected from the target 2 is compared with the detection signal, and related information of the target 2, such as parameters of a distance, an azimuth, an altitude, a speed, an attitude, and even a shape of the target 2, is obtained through a specific algorithm, so that the target 2 can be detected, tracked, and identified.

In other examples, however, the laser three-dimensional scanning measurement apparatus 1 according to the present disclosure may be not limited to the laser radar device.

As shown in connection with fig. 1 and 2, the laser three-dimensional scanning measurement apparatus 1 according to the present disclosure may include a first rotating part 11. In some examples, the laser three-dimensional scanning measurement device 1 may further comprise a second rotating part 12. In some examples, the laser three-dimensional scanning measurement device 1 may further comprise a base 13. In some examples, the laser three-dimensional scanning measurement device 1 may further comprise a beam deflecting body 14. In some examples, the laser three-dimensional scanning measurement device 1 may further comprise a fiber optic light path system 15. That is, the laser three-dimensional scanning measurement apparatus 1 according to the present disclosure may include a first rotating portion 11, a second rotating portion 12, a base 13, a beam deflecting body 14, and an optical fiber optical path system 15. Specifically, the beam deflecting body 14 may be provided to the second rotating part 12 and may be coupled with the second rotating part 12, and the base 13 may be provided with the optical fiber optical path system 15.

As shown in fig. 3, the fiber optic system 15 may include a frequency modulated laser light source 151 and a detection assembly 152. In some examples, fiber optic system 15 may also include polarization maintaining fiber 150, i.e., fiber optic system 15 may include a frequency modulated laser source 151, a detection assembly 152, and polarization maintaining fiber 150. In this case, the polarization maintaining optical fiber 150 can ensure the linear polarization direction unchanged, and improve the coherence signal to noise ratio to achieve high-precision measurement of the distance of the target 2, thereby having a polarization maintaining effect satisfying the measurement requirement even if the beam deflecting body 14 does not employ a mirror type optical path structure.

As shown in fig. 5, in some examples, the beam deflecting body 14 may include a measurement interferometer 141. In some examples, the beam deflecting body 14 may include a focusing device 142. In some examples, the beam deflecting body 14 may include an overview camera device 143. That is, the beam deflecting body 14 may include a measurement interferometer 141, a focusing device 142, and an overview camera device 143. In this case, since the measurement interferometer 141 is provided to the beam deflecting body 14, the measurement signal and the local oscillation signal share the polarization maintaining fiber 150 between the beam deflecting body 14 and the base 13, and the measurement accuracy can be improved. Specifically, the polarization maintaining fiber 150 is easily interfered by temperature and vibration, after the polarization maintaining fiber 150 is connected to the collimating module 1411, errors may be introduced due to the fact that the polarization maintaining fiber 150 is pulled by the movement of the beam deflecting body 14, and the measurement signal (i.e., the subsequent first reflected beam) and the local oscillation signal (i.e., the subsequent second beam) share the polarization maintaining fiber 150 between the beam deflecting body 14 and the base 13, and the measurement interferometer 141 can interfere the measurement signal and the local oscillation signal to form a common mode signal (i.e., a measurement interference signal) so as to reduce the influence of environmental interference such as rotational vibration, temperature change and the like on the measurement accuracy in a differential mode, that is, the anti-interference performance of measurement can be improved, and the measurement accuracy is improved.

In some examples, measurement interferometer 141 can be configured to generate measurement interference signals based on the measurement beam. In some examples, measurement interferometer 141 can be configured as a "fabry-perot" (F-P) interferometer structure and generate measurement interference signals based on the measurement beam.

In some examples, as shown in fig. 1 or 2, the first rotating part 11 may be provided to the base 13. Specifically, as shown in fig. 2, the base 13 and the first rotating portion 11 may be rotatably connected by a first rotating mechanism 110. In some examples, the first rotation mechanism 110 may have the first axis Z as a rotation axis. That is, the first rotating portion 11 may be provided on the base 13 and rotate relative to the base 13 about the first axis Z as a rotation axis.

In some examples, the first axis Z may be a central axis of the first rotation mechanism 110. In some examples, the first rotation mechanism 110 may include a drive motor, a fixed bearing, a shaft, and an angle measurement device, referred to herein as "first drive motor 111", "first fixed bearing 112", "first shaft 113", and "first angle measurement device 114" for ease of distinction.

In some examples, the first rotation shaft 113 may be used to connect the first rotation portion 11 and the base 13. In some examples, the cooperation of the first rotation shaft 113 and the first fixed bearing 112 may rotate the first rotation part 11 with respect to the base 13, and the first driving motor 111 may drive the first rotation shaft 113 and the first fixed bearing 112 to rotate with respect to the base 13. The rotation axis of the first rotation portion 11 with respect to the base 13 may be the first axis Z.

In some examples, the first angle measurement device 114 may be configured to obtain the rotation angle of the first rotation part 11, i.e. to obtain the first deflection angle of the target 2. In some examples, the first angle of deflection is the angle of deflection of the target 2 relative to the first axis Z. In this case, it is possible to accurately track the measurement on the target 2 by obtaining the first deflection angle of the target 2.

In some examples, as shown in connection with fig. 2 and 3, a fm laser light source 151 may be provided to the base 13 and used to generate the measuring beam.

In some examples, as shown in fig. 2, polarization maintaining fiber 150 may direct the measuring beam from base 13 to beam deflecting body 14 along first axis Z. Specifically, the polarization maintaining fiber 150 may guide the measuring beam from the base 13 along the first axis Z to the beam deflecting body 14 through the first rotating part 11. In this case, while the base 13 and the first rotating part 11 can relatively rotate, the measuring beam can be guided from the base 13 to the beam deflecting body 14 by using the optical fiber optical path (i.e., the polarization maintaining optical fiber 150), thereby being capable of facilitating the tracking measurement of the target 2 by the laser three-dimensional scanning measuring apparatus 1 with the first axis Z as the rotation axis, for example, driving the first rotating part 11 to rotate in the horizontal direction so that the beam deflecting body 14 can track the target 2 (i.e., the first deflection angle of the target 2 can be the horizontal deflection angle).

In some examples, as shown in fig. 1 or 2, the second rotating part 12 may be provided to the first rotating part 11. Specifically, as shown in fig. 2, the first rotating portion 11 and the second rotating portion 12 may be rotatably connected by a second rotating mechanism 120. In some examples, the second rotating portion 12 may have the second axis X as a rotation axis. In some examples, the second axis X may be orthogonal to the first axis Z. That is, the second rotating portion 12 may be provided in the first rotating portion 11 and may rotate with respect to the first rotating portion 11 about a second axis X orthogonal to the first axis Z as a rotation axis.

In some examples, the second axis X may be a central axis of the second rotation mechanism 120. In some examples, the second rotation mechanism 120 may also include a drive motor, a fixed bearing, a spindle, and an angle measurement device, referred to herein as "second drive motor 121", "second fixed bearing 122", "second spindle 123", and "second angle measurement device 124" for ease of distinction. In some examples, the second shaft 123 may be used to connect the second rotating part 12 and the first rotating part 11.

In some examples, the cooperation of the second rotation shaft 123 and the second fixed bearing 122 may rotate the second rotation part 12 with respect to the first rotation part 11, and the second driving motor 121 may drive the second rotation shaft 123 and the second fixed bearing 122 to rotate the second rotation part 12 with respect to the first rotation part 11. The rotation axis of the second rotating portion 12 relative to the first rotating portion 11 may be the second axis X.

In some examples, the second angle measurement device 124 may be configured to obtain the rotation angle of the second rotation portion 12, i.e. to obtain the second deflection angle of the target 2. In some examples, the second angle of deflection is the angle of deflection of the target 2 relative to the second axis X. In this case, it is possible to accurately track the measurement on the target 2 by obtaining the second deflection angle of the target 2.

In some examples, as shown in fig. 2, the polarization maintaining fiber 150 may direct the measuring beam from the first rotating part 11 to the beam deflecting body 14 along the second axis X. Specifically, the polarization maintaining fiber 150 may guide the measuring beam from the base 13 through the first rotating part 11 along the first axis Z and then guide the measuring beam from the first rotating part 11 to a measuring interferometer 141 (described later) in the beam deflecting body 14 along the second axis X. In this case, the measuring beam can be guided from the base 13 to the measuring interferometer 141 by using the optical fiber path while the first rotating portion 11 and the second rotating portion 12 are relatively rotated, whereby tracking measurement of the target 2 by the laser three-dimensional scanning measuring apparatus 1 with the second axis X as the rotation axis can be facilitated, for example, the second rotating portion 12 is driven to rotate in the vertical direction so that the beam deflecting body 14 tracks the target 2 (i.e., the second deflecting angle of the target 2 may be a pitch deflecting angle).

In some examples, the first rotation part 11 may have a symmetrical shape and a concave part in the middle. In some examples, the second rotating portion 12 may be located in a recess. In some examples, the first axis Z may coincide with a line of symmetry of the first rotation portion 11. In this case, the laser three-dimensional scanning measuring apparatus 1 can be made to have a better balance.

In some examples, polarization maintaining fiber 150 passes through base 13, first rotating section 11, and second rotating section 12 in order to direct the measurement beam to measurement interferometer 141.

In the present disclosure, a frequency modulation laser source 151 is disposed on a base 13, a laser beam emitted from the frequency modulation laser source 151 propagates through a polarization maintaining fiber 150 inside an optical fiber optical path system 15 to obtain a measurement beam, the polarization maintaining fiber 150 guides the measurement beam from the base 13 to a measurement interferometer 141 disposed in a beam deflection main body 14 of a second rotating portion 12, and a measurement signal of the measurement interferometer 141 (i.e., a signal obtained after the measurement beam is reflected by a target 2) is returned to a detection component 152 in the base 13 through the guide of the polarization maintaining fiber 150, thereby forming an optical fiber path. In this case, the measuring beam can be guided by the optical fiber path instead of the existing mirror-type optical path scheme so as to perform the measurement work, i.e., the higher processing requirements for the mirrors in the mirror-type optical path scheme can be reduced.

In addition, compared with the existing mirror-type optical path scheme, the optical beam deflection main body 14 arranged on the second rotating part 12 has higher adaptability to space, for example, the frequency modulation laser light source 151 is arranged on the base 13, the measuring interferometer 141, the focusing device 142 and the overview camera device 143 are arranged on the optical beam deflection main body 14, and the defects of long structure, heavy volume and the like of the base 13 caused by that structures such as the optical fiber optical path system 15, the measuring interferometer 141, the focusing device 142 and the overview camera device 143 are arranged on the base 13 in the existing mirror-type optical path scheme are avoided. Thereby, it is possible to facilitate optimization of the structural arrangement of the laser three-dimensional scanning measuring apparatus 1 and to improve the degree of light weight and the compactness of the structure of the laser three-dimensional scanning measuring apparatus 1.

Fig. 7 is a schematic diagram showing the operation principle of the laser three-dimensional scanning measurement apparatus 1 of the first embodiment according to the example of the present disclosure. Fig. 8 is a schematic diagram showing the operation principle of the laser three-dimensional scanning measurement apparatus 1 of the second embodiment according to the example of the present disclosure. Fig. 9 is a schematic diagram showing the operation principle of a laser three-dimensional scanning measurement apparatus 1 of a third embodiment according to an example of the present disclosure. Wherein the solid lines with arrows illustrate the beam and its direction in the laser three-dimensional scanning measurement device 1, the dashed lines in the chirped laser light source 151 illustrate its chirped waveform, and the dashed lines behind the collimation module 1411 in fig. 8 and 9 illustrate the transmission, reflection and focusing of the light.

As described above, the beam deflecting body 14 may include the measurement interferometer 141. In some examples, the beam deflecting body 14 may be provided in the second rotating part 12, i.e. the measurement interferometer 141 may be located in the second rotating part 12.

In some examples, as shown in fig. 6 or 7, measurement interferometer 141 can include a collimation module 1411, a polarization module 1412, and a partially reflective component 1413.

In some examples, the partially reflective component 1413 may be configured to receive the measurement beam and split the measurement beam into a first beam and a second beam.

As shown in fig. 7, in some examples, the first light beam may be transmitted to the target 2 via the partially reflective component 1413 and reflected by the target 2 to form a first reflected light beam. In some examples, the second light beam may be a light beam that the measuring light beam reflects via the partially reflective component 1413 to obtain. In this case, the measuring beam is transmitted through the partially reflecting component 1413 to obtain the first beam, and the first beam is reflected by the target 2 to obtain the first reflected beam, or the measuring beam is directly reflected by the partially reflecting component 1413 to obtain the second beam, so that the first reflected beam and the second beam share one optical fiber path, that is, the partially reflecting component 1413 and the target 2 can form a "fabry-perot" (F-P) interferometer structure so that the first reflected beam and the second beam interfere in one optical fiber path, thereby obtaining the distance of the target 2 by using the interference result of the first reflected beam and the second beam in the optical fiber path, and forming the first reflected beam and the second beam into a common mode signal based on the characteristics of the "fabry-perot" (F-P) interferometer so as to reduce the influence of the environmental interference such as rotational vibration and temperature change on the measuring accuracy.

In some examples, the partially reflecting component 1413 may include an all-fiber partial reflector (or "all-fiber partial mirror"). In the present disclosure, the all-fiber partial reflector may reflect a portion of the measuring beam back to the input end of the all-fiber partial reflector, i.e., may form the second beam, while another portion of the measuring beam is transmitted to the output end, i.e., may form the first beam. The first light beam is reflected by the target 2 to form a first reflected light beam and is returned to the input end of the all-fiber portion reflector.

In some examples, the all-fiber partial reflector may form the second beam by separating the measuring beam, and directing a portion of the measuring beam back to the input end using a reflective film.

In some examples, the connector end of the all-fiber partial reflector may be uncoated and the second beam is formed by reflecting (about 4% reflectivity) the beam off the fiber end face. In this case, the all-fiber partial reflector can be freely connected to other fiber jumpers, for example, to a collimating module 1411 (described later), whereby all-fiber operation can be fully achieved.

In some examples, the partially reflective component 1413 may include a single mode fiber partial reflector.

In some examples, as shown in fig. 6 or 7, the measurement interferometer 141 can also include a collimation module 1411. In some examples, the collimation module 1411 may be used to collimate the measuring beam. In some examples, the collimation module 1411 may cooperate with the partially reflective assembly 1413 to collimate the measuring beam. In this case, after the measuring beam is collimated by the collimating module 1411, the divergence of the measuring beam can be reduced to make the measuring beam collimated (parallel light), so that the beam quality of the measuring beam incident on the partially reflecting component 1413 can be improved.

In some examples, the collimation module 1411 can be disposed between the partially reflective component 1413 and the end fibers of the polarization maintaining fiber 150. I.e., the end optical fiber is connected to the collimating module 1411, the exit end of the collimating module 1411 corresponds to the entrance end of the partially reflective component 1413. In this case, the measuring beam, when collimated by the collimating module 1411, can directly enter the partially reflecting assembly 1413 to be transmitted or reflected in the partially reflecting assembly 1413 to form a first beam and a second beam.

In some examples, as shown in fig. 6 or 7, measurement interferometer 141 can further include a polarization module 1412. In some examples, the polarization module 1412 may be configured to adjust the polarization state of the measuring beam. In this case, after the first light beam (or the first reflected light beam) and the second light beam in the measuring light beam are adjusted by the polarization module 1412, they are respectively converted into polarized light beams with specific polarization states, for example, the first light beam with linear polarization is converted into circular polarized light or elliptical polarized light, or vice versa, so that the independence and stability of the first light beam and the second light beam in the measuring light beam can be improved, and thus the transmission quality of each of the first light beam and the second light beam in the optical fiber path can be improved, so that the detection component 152 can better detect the interference signals formed by the first reflected light beam and the second light beam, that is, the measurement interference signals.

In some examples, the polarization module 1412 may be a polarization wave plate, such as a quarter wave plate. In some examples, preferably, the polarizing module 1412 may be disposed between the collimating module 1411 and the partially reflecting component 1413. In this case, the first beam (or the first reflected beam) and the second beam of the measuring beam can directly enter the polarization module 1412 to adjust the polarization state after being collimated by the collimating module 1411, so that the polarized beams can be respectively converted into polarized beams of a specific polarization state and enter the partially reflecting component 1413. For example, after the measurement beam having P linear polarization passes through the polarization module 1412, the polarization state of the measurement beam is changed into circular polarized light, the first reflected beam transmitted through the partially reflecting component 1413 and reflected by the target 2 and the second beam reflected by the partially reflecting component 1413 pass through the polarization module 1412 again, and the polarization states of the first reflected beam and the second beam become S linear polarized light at 90 ° with the P linear polarized light of the outgoing measurement beam, so that the outgoing measurement beam and the reflected beam (i.e., the first reflected beam and the second beam) are polarized and separated, and finally, an interference signal with a higher signal-to-noise ratio (a signal generated by interference between the first reflected beam and the second beam) is detected in the detecting component 152.

Although not disclosed as being limited thereto, the measurement interferometer 141 can also be configured in other configurations, for example, in some examples, the measurement interferometer 141 can include a collimation module 1411, a polarization module 1412, a partially reflective component 1413, and a reflector, wherein the partially reflective component 1413 can be a beam splitter with a reflective surface positioned at 45 degrees to the optical axis, the partially reflective component 1413 can be transmitted and form a first light beam when the measurement light beam is collimated by the collimation module 1411, the first light beam can be reflected by the target 2 to form a first reflected light beam, the partially reflective component 1413 can be reflected to the reflector when the measurement light beam is collimated by the collimation module 1411, a second light beam can be formed at the reflector and reflected back to the partially reflective component 1413, and the first reflected light beam can be combined with the second light beam and interfere in the partially reflective component 1413.

As described above, the beam deflecting body 14 may further include a focusing device 142, as shown in fig. 5 or 8. In particular, the fiber optic system 15 may include a focusing device 142 for focusing the first light beam onto the target 2.

In some examples, the focusing device 142 may be located between the measurement interferometer 141 and the target 2, the focusing device 142 may have a plurality of lenses and a driving mechanism, and at least one lens is moved by the driving mechanism to adjust the focus position of the focusing device 142. In this case, the spot size of the first beam can be compressed by the focusing means 142 such that the measuring beam is focused onto a spot on the target 2 (the size of the focused spot depends on the size of the focused spot, which is distance-dependent, from a few meters to a few tens of meters, and the focused spot size can be from a few tens of micrometers to a few millimeters). This makes it possible to make the signal of the light reflected by the object 2 stronger and at the same time to make the lateral resolution of the measurement higher and the measurement distance stability higher. Likewise, when there is an indication beam (described later), such as a red indication beam, the red indication beam can also be focused to the target 2 by the focusing device 142 for assisting in discriminating whether the measurement beam is aimed at the target 2 or focused to the target 2. In some examples, the red indicator beam may be coupled to the fiber optic system 15 by the fiber coupling assembly 154 with the measurement beam, in particular, may be coupled to the polarization maintaining fiber 150 and directed to the beam deflecting body 14 along with the measurement beam.

In some examples, the manner in which the focusing device 142 focuses the first light beam may be at least one of an auto-focusing manner or a manual focusing manner.

In some examples, focusing device 142 may be configured as a cross-band achromatic focusing optical system, for example, to achieve a cross-band beam focusing of red indicating light having a wavelength of 650nm (nanometers) and a measuring beam having a wavelength of 1550nm to target 2.

In some examples, the focusing device 142 may be a lens combination or an off-axis parabolic mirror combination.

In some examples, the focusing device 142 may be disposed at the second rotating portion 12. In some examples, the focusing device 142 may be disposed behind the partially reflective assembly 1413 and cooperate with the partially reflective assembly 1413, i.e., the measuring beam may be incident on the focusing device 142 after being transmitted through the partially reflective assembly 1413 and focused by the focusing device 142 at the target 2.

As described above, the beam deflecting body 14 may further comprise an overview camera device 143, as shown in fig. 5 or 9. Specifically, the laser three-dimensional scanning measurement device 1 may include an overview camera device 143 provided to the second rotating part 12 for acquiring an image of the target 2. In some examples, the overview camera 1432 may be used to acquire at least one of an overview image of the target 2, a measurement region of the target 2, and an image indicating that the light beam is located at the target 2. In some examples, the image processing circuit 1433 may perform recognition processing on an overview image of the target 2, a measurement region of the target 2, or an image indicating that the measuring beam is located on the target 2, thereby enabling accurate determination of whether the measuring beam is located on the target 2. In this case, it is possible to perform positioning of the measurement target 2 by the image of the target 2 and beam deflection control according to the image coordinates and to make a measurement plan according to the image to achieve rapid measurement of the region.

In some examples, the overview image may refer to an image of the object 2 in the overview camera device 143. In some examples, the measurement region may refer to a region in the image of the target 2 that may be selected as a measurement point. In some examples, the image indicating that the light beam is located at the target 2 may be confirmed by observation of the target 2 in the image made in the overview camera apparatus 143.

In some examples, as shown in fig. 9, the overview camera device 143 may include at least one mirror 1431, an overview camera 1432, and an image processing circuit 1433. In some examples, the mirror 1431 is used for optical path refraction such that the optical axis of the overview camera 1432 is aligned with (e.g., overlaps) the optical axis of the measurement beam, enabling the overview camera device 143 to be arranged coaxially with the measurement beam.

In some examples, disposing the overview camera device 143 coaxially with the measuring beam may refer to refractive coupling of the optical axis of the overview camera 1432 to the optical axis of the measuring beam with the mirror 1431. In some examples, the number of mirrors 1431 may be 1 or a plurality. Preferably, the number of mirrors 1431 may be 2. Thus, the 2 mirrors 1431 facilitate the arrangement of the overview camera device 143 and the exit opening of the beam deflecting body 14 in parallel.

In some examples, the overview camera device 143 may acquire image coordinates of any point on the image from the acquired image, may calculate the rotation angles of the first rotation part 11 and the second rotation part 12 from the relative coordinates to the image center coordinates and the focal length of the overview camera 1432, and control the beam deflection main body 14 of the laser three-dimensional scanning measurement apparatus to aim at a specified coordinate point position where the image is acquired, that is, the overview camera device 143 may perform beam deflection control according to the image coordinates.

In some examples, the overview camera device 143 may frame a working area on the acquired image according to the acquired image, set a scan range and a scan point distance, that is, make a measurement plan according to the image, and implement rapid scan measurement of the area. The working area may be any arbitrary shape such as rectangular, square, triangular, circular, polygonal, or irregular shape, etc. on the captured image.

In some examples, the optical path system provided to the beam deflecting body 14 may also be referred to as a spatial optical path system. The laser three-dimensional scanning measurement device 1 can separate the positions of the optical fiber optical path system 15 and the spatial optical path system. Because the space optical path system relates to tasks such as focusing of the target 2 and acquisition of a preview image, and the target 2 needs to be aligned, the space optical path system is arranged on the beam deflection main body 14 with relatively flexible movement; meanwhile, since the optical fiber optical path system 15 includes the optical fiber, the fm laser source 151, and other components, it is easily affected by temperature and equipment movement, and more detection equipment (such as the auxiliary interferometer 153 and the temperature control structure 16) is required to control and monitor the working environment of the optical fiber optical path system 15 in real time, in order to achieve light weight of the structure, and simplify the structure of the beam deflection main body 14, the optical fiber optical path system 15 can be disposed on the base 13. In addition, the optical fiber optical path system 15 and the spatial optical path system are connected by the optical fiber, and stable coupling of the optical fiber optical path system 15 and the spatial optical path system can be achieved by using the flexibility of the polarization maintaining optical fiber 150.

In some examples, as shown in fig. 9, the laser three-dimensional scanning measurement device 1 may further include an auxiliary interferometer 153. In some examples, the auxiliary interferometer 153 may generate an auxiliary measurement signal based on the measurement beam to achieve non-linearity correction of the frequency modulated laser light source 151. Specifically, the auxiliary interferometer 153 may perform linear correction or compensation on the frequency modulated laser light source 151 based on the third beam. In some examples, the third light beam may be a light beam obtained after the measurement light beam is split via the fiber coupling assembly 154. In this case, the measurement beam stability can be improved by linearly compensating the fm laser light source 151, that is, by non-linearly correcting the fm laser light source 151 by the auxiliary interferometer 153, thereby improving the fm linearity of the measurement laser, and thus the measurement accuracy can be improved.

In some examples, the auxiliary interferometer 153 may obtain a portion of the measurement beam from the polarization maintaining fiber polarizing beam splitter 1541, i.e., the auxiliary interferometer 153 may obtain a third beam from the polarization maintaining fiber polarizing beam splitter 1541.

In some examples, the correction principle of the auxiliary interferometer 153 may be to delay a part of the third light beam by a delay fiber to form an optical path difference with the original third light beam, and calculate the reference distance based on the optical path difference.

In some examples, the laser three-dimensional scanning measurement device 1 may determine whether actual measurement information is accurate based on the reference distance, and may linearly compensate the modulated laser light source 151 according to the determination result.

In some examples, the auxiliary interferometer 153 includes at least one photodetector operable to detect the portion of the third beam delayed by the delay fiber and the remaining portion of the third beam so as to obtain the aforementioned optical path difference. That is, the photodetector may receive the auxiliary measurement signal to enable resolution of the reference distance (i.e., to obtain the reference distance of the target 2).

In some examples, because fiber optic system 15 may be shared, photodetectors in auxiliary interferometer 153 may also be partitioned into detection assemblies 152 based on logical partitioning. That is, the detection assembly 152 may include a plurality of photodetectors, wherein at least one photodetector may be used to detect the first reflected light beam and the second light beam and at least another photodetector may be used to detect the portion of the third light beam delayed by the delay fiber and the remaining portion of the third light beam. In other words, the detection assembly 152 may receive the auxiliary measurement signal and the interference signal of the measurement interferometer 141 to achieve absolute distance resolution (i.e., obtain the measured distance of the target 2).

As described above, the fiber optic system 15 may include a detection assembly 152. In some examples, detection component 152 may be configured to receive measurement interference signals to obtain a distance of target 2. In particular, as shown in fig. 7 or 8, in some examples, detection assembly 152 may be configured to receive interference signals of the first reflected light beam and the second light beam to detect target 2.

In some examples, the detection component 152 may be configured to obtain the distance between the partially reflective component 1413 and the target 2 based on the interference signals of the first reflected light beam and the second light beam. In this case, the distance of the target 2 can be obtained using the interference results of the first reflected light beam and the second light beam in the optical fiber optical path, while the first reflected light beam and the second light beam can be used as common mode signals based on the characteristics of the "fabry-perot" (F-P) interferometer structure, whereby the influence of environmental disturbance such as rotational vibration, temperature change, etc. on the measurement accuracy can be reduced by the differential form.

In some examples, detection assembly 152 may include at least one photodetector.

In some examples, the first reflected beam and the second beam may be directed into a photodetector through a fiber optic optical path system 15. In some examples, a photodetector may be used to detect the first reflected light beam and the second light beam. In some examples, the photodetector may convert the optical frequency signals of the first reflected light beam and the second light beam into electrical signals and then transmit the electrical signals to the signal processing system for processing. In this case, the first reflected light beam and the second light beam can be detected and the distance of the target 2 can be obtained. That is, the photodetector may receive the interference signal of the measurement interferometer 141 to achieve resolution of the absolute distance.

In some examples, the detection assembly 152 may be disposed between the fm laser source 151 and the measurement interferometer 141 and connected to the measurement interferometer 141 by a fiber coupling assembly 154 (described later), such as a polarization maintaining fiber circulator 1543, and a polarization maintaining fiber 150.

In some examples, the detection assembly 152 may be disposed on the base 13. In some examples, the first reflected light beam and the second light beam may be directed through a fiber optic coupling assembly 154 and polarization maintaining fiber 150 to a detection assembly 152 located at the base 13.

In some examples, the fiber optic system 15 may also include a fiber coupling assembly 154.

As shown in fig. 7 or 8, in some examples, the fiber coupling assembly 154 may be configured to form a fiber optic path with the polarization maintaining fiber 150 to direct the measurement beam from the base 13 to the partially reflective assembly 1413, and the fiber coupling assembly 154 may direct the first reflected beam and the second beam to the detection assembly 152. In this case, since the optical fiber path structure is simple and the space occupation is small, it is possible to facilitate the subsequent setting of the focusing device 142, the overview camera device 143, and the like in the second rotating portion 12, and the base 13 is provided with the fm laser light source 151 and a part of the optical fiber path, and thus it is possible to reduce the volume of the laser three-dimensional scanning measurement apparatus 1, optimize the apparatus structure, and thereby it is possible to achieve the effects of light weight and compact structure of the laser three-dimensional scanning measurement apparatus 1.

In some examples, the fiber optic coupling assembly 154 is used to perform various pre-treatments on the measuring beam, such as splitting, adjusting the exit direction, combining with the auxiliary beam, and the like. In this case, the measuring beam or other auxiliary beam can be better directed into a particular assembly by the fiber optic coupling assembly 154.

In some examples, the indication beam may be directed through polarization maintaining fiber 150 and coupled to fiber optic system 15 through fiber coupling assembly 154.

Specifically, for example, the optical fiber coupling assembly 154 splits the measuring beam, so that the measuring beam can be detected and corrected by the auxiliary interferometer 153 arranged later; synchronizing the pointer beam and the measuring beam in one optical path after combining the measuring beam and the pointer beam (i.e., the auxiliary beam) by, for example, the fiber coupling assembly 154 can facilitate distinguishing by the pointer beam whether the measuring beam is aimed at the target 2; tuning the direction of emission of the measuring beam, for example by means of the fiber coupling assembly 154, can facilitate accurate guiding of the measuring beam emitted by the chirped laser light source 151 to the partially reflecting assembly 1413 and accurate guiding of the first reflected beam or the second beam into the photodetector.

In some examples, as shown in fig. 8, the fiber coupling assembly 154 may include a polarization maintaining fiber polarizing beam splitter 1541 (Polarization Beam Splitter, abbreviated as PBS, also known as a polarizing beam splitter prism). In some examples, polarization maintaining fiber polarizing beam splitter 1541 may be disposed in the fiber optic path between frequency modulated laser source 151 and partially reflective assembly 1413. By dividing the measuring beam emitted from the fm laser light source 151 into, for example, a beam with power of 5% and 95% respectively using the polarization maintaining fiber polarization beam splitter 1541, the beam with power of 5% can be used for detection in the auxiliary interferometer 153 (described later) and the detection result is obtained to correct the modulation nonlinearity of the fm laser light source 151, and the beam with power of 95% can be continuously output to the partially reflecting assembly 1413 to continue the distance for detecting the target 2.

In some examples, as shown in fig. 8, the fiber coupling assembly 154 may include a polarization maintaining fiber wavelength division multiplexer 1542. In some examples, polarization maintaining fiber wavelength division multiplexer 1542 may be disposed in the fiber optic path between frequency modulated laser source 151 and partially reflective component 1413. In this case, the measuring beam or other beam (e.g., indicating beam) which has been separated can be introduced into the optical fiber path, for example, when the indicating beam is introduced, the indicating beam is emitted to the target 2 together with the measuring beam, whereby it can be facilitated to judge whether the measuring area of the target 2 is accurate or not by the indicating beam.

In some examples, as shown in fig. 8, the fiber coupling assembly 154 may include a polarization maintaining fiber circulator 1543. In some examples, a polarization maintaining fiber circulator 1543 may be disposed in the fiber optic path between the chirped laser light source 151 and the partially reflective component 1413. In this case, a specific light beam in the optical fiber path can be guided to a specific component, for example, the measuring light beam emitted from the fm laser light source 151 can be accurately guided to the partially reflecting assembly 1413, or the reflected first reflected light beam or second light beam can be accurately guided to the photodetector, whereby the optical fiber path system 15 can be further simplified, and the compactness of the apparatus structure can be improved.

In some examples, polarization maintaining fiber circulator 1543 may also be replaced by polarization maintaining fiber polarization beam splitter 1541 (not shown in the figures), polarization maintaining fiber polarization beam splitter 1541 may have three ports, the common port may transmit P-polarized light and S-polarized light simultaneously, the beam splitting port includes a P-polarized port and an S-polarized port (when the polarization direction is in a plane spanned by the incident light beam and the reflected light beam, the linear polarization state is denoted as P-polarization, the polarization perpendicular thereto is referred to as S-polarization), the P-polarized measuring light beam enters from the P-polarized port of polarization maintaining fiber polarization beam splitter 1541, passes through polarization module 1412, the polarization state of the measuring light beam becomes circularly polarized light, passes through the first reflected light beam reflected by partial reflection component 1413 and the second light beam transmitted by partial reflection component 1413 and reflected by target 2 again passes through polarization module 1412, the polarization states of the first reflected light beam and the second light beam become S-polarized light at 90 ° to the P-linear light of the outgoing measuring light beam, passes through polarization maintaining fiber polarization beam splitter 1541 again, and is output from the S-polarized port to probe assembly, such as probe 152. Therefore, polarization separation of the emergent light beam and the reflected light beam in the same optical axis transmission can be realized, polarization crosstalk is reduced, and finally, an interference signal with higher signal-to-noise ratio is detected in the detection module, so that the measurement accuracy is improved.

In some examples, as shown in fig. 8, the polarization maintaining fiber polarization beam splitter 1541, the polarization maintaining fiber circulator 1543, and the polarization maintaining fiber wavelength division multiplexer 1542 may be sequentially disposed in the fiber optical path, that is, the measuring beam of the fm laser source 151 may reach the polarization maintaining fiber polarization beam splitter 1541, then reach the polarization maintaining fiber circulator 1543, and finally reach the polarization maintaining fiber wavelength division multiplexer 1542. In this case, the measurement beam obtained by first splitting can be detected in the auxiliary interferometer 153 (described later) to obtain a more accurate detection result, and finally the indication beam introduced through the polarization maintaining fiber wavelength division multiplexer 1542 can reduce the energy loss of the indication beam in a longer fiber optical path, and the polarization maintaining fiber circulator 1543 can facilitate simplifying the fiber optical path after the polarization maintaining fiber polarization beam splitter 1541.

In some examples, polarization maintaining fiber polarization beam splitter 1541, polarization maintaining fiber circulator 1543, and polarization maintaining fiber wavelength division multiplexer 1542 of fiber coupling assembly 154 may be disposed at base 13.

In some examples, as shown in fig. 8, the fiber coupling assembly 154 may also include a polarization maintaining fiber isolator 1544. In some examples, polarization maintaining fiber isolator 1544 may be used to couple and isolate frequency modulated laser source 151 and polarization maintaining fiber 150. In this case, the degradation of the spectral purity of the fm laser light source 151 due to the effect of the back propagation of the first reflected light beam and the second light beam or the unstable light source modulation or unstable output power can be reduced by the polarization maintaining fiber isolator 1544.

In some examples, as shown in fig. 8, the fiber optic system 15 may also include an indicator light source 155. The indication light source 155 is used to generate an indication light beam, such as a red indication light, to indicate the target 2, the indication light beam being directed through the polarization maintaining fiber 150 and coupled to the polarization maintaining fiber 150 in the fiber optic path system 15 through the fiber coupling assembly 154. With the indicator beam, the indicator beam may be coupled to the polarization maintaining fiber 150 by the fiber coupling assembly 154 with the measurement beam and directed to the beam deflecting body 14 along with the measurement beam, and the indicator beam may also be focused by the focusing device 142 to the target 2 for aiding in discriminating whether the measurement beam is aimed at the target 2 or focused to the target 2.

In some examples, the chirped laser light source 151 may be a chirped laser light source 151. In some examples, the fm laser light source 151 may emit fm laser light having a wavelength between 900 nm and 1600 nm. Preferably, the frequency modulated laser source 151 of the present disclosure emits a frequency modulated laser light having a length of 1550 nm. In other examples, the frequency modulated laser light source 151 of the laser three-dimensional scanning measurement apparatus 1 of the present disclosure may also be unlimited.

In some examples, as shown in fig. 2, the laser three-dimensional scanning measurement device 1 may further include a temperature control structure 16. In some examples, the temperature control structure 16 may be a multiple temperature control structure, i.e., the temperature control structure 16 may have multiple layers of hierarchy for temperature regulation. In some examples, the temperature control structure 16 may be provided to the base 13.

In some examples, at least a portion of the polarization maintaining fiber 150 may be located in the temperature control structure 16. In some examples, the temperature control structure 16 may be used to improve the environmental stability of the fiber optic system 15. In some examples, the fiber optic system 15 may also be located in the temperature control structure 16. In this case, temperature adjustment of the base 13 and the polarization maintaining fiber 150 can be achieved, whereby constant temperature operation of the polarization maintaining fiber and the fiber optical path system 15 can be achieved to improve measurement accuracy.

According to the present disclosure, it is possible to provide a laser three-dimensional scanning measurement apparatus 1 capable of improving the degree of weight reduction of the apparatus, the compactness of the structure, and the interference resistance of the measurement accuracy.

While the disclosure has been described in detail in connection with the drawings and embodiments, it should be understood that the foregoing description is not intended to limit the disclosure in any way. Modifications and variations of the present disclosure may be made as desired by those skilled in the art without departing from the true spirit and scope of the disclosure, and such modifications and variations fall within the scope of the disclosure.

Claims (10)

1. The laser three-dimensional scanning measurement device is a device for detecting the distance of a target based on a laser radar principle and is characterized by comprising a base, a first rotating part which is arranged on the base and rotates by taking a first axis as a rotating shaft, a second rotating part which is arranged on the first rotating part and rotates by taking a second axis orthogonal to the first axis as a rotating shaft, and a beam deflection main body which is arranged on the second rotating part and is linked with the second rotating part, wherein the beam deflection main body comprises a measurement interferometer which is configured to generate a measurement interference signal based on a measurement beam, the base is provided with an optical fiber optical path system, the optical fiber optical path system comprises a frequency modulation laser source which is used for generating a linear frequency modulation laser as the measurement beam and a detection assembly which is configured to receive the measurement interference signal so as to obtain the distance of the target, the measurement interferometer is connected with the frequency modulation laser source through polarization maintaining optical fibers, and the polarization maintaining optical fibers sequentially pass through the base, the first rotating part and the second rotating part so as to guide the measurement beam to the measurement interferometer.

2. The laser three-dimensional scanning measurement device of claim 1, wherein the beam deflecting body further comprises a focusing arrangement between the measurement interferometer and the target, the focusing arrangement configured to focus the measurement beam to the target.

3. The laser three-dimensional scanning measurement device of claim 1, wherein the beam deflecting body further comprises an overview camera arrangement configured to acquire an image of the target, an optical axis of the overview camera arrangement being arranged coaxially with the measuring beam.

4. The laser three-dimensional scanning measurement device of claim 1, wherein the base is further provided with a temperature control structure for improving environmental stability of the fiber optic path system, and at least a portion of the polarization maintaining fiber is located in the temperature control structure.

5. The laser three-dimensional scanning measurement device of claim 1, wherein the base and the first rotating portion are rotatably connected by a first rotating mechanism, the first axis being a central axis of the first rotating mechanism, and a polarization maintaining fiber guides the measurement beam from the base to the beam deflecting body along the first axis.

6. The laser three-dimensional scanning measurement device of claim 5, wherein the first rotating portion and the second rotating portion are rotatably connected by a second rotating mechanism, the second axis being a central axis of the second rotating mechanism, and a polarization maintaining fiber directs the measurement beam from the first rotating portion to the measurement interferometer at the second rotating portion along the second axis.

7. The laser three-dimensional scanning measurement device of claim 6, wherein the first rotation mechanism includes a first angle measurement device for obtaining a first angle of deflection of the target and the second rotation mechanism includes a second angle measurement device for obtaining a second angle of deflection of the target.

8. The laser three-dimensional scanning measurement device according to claim 1, wherein the first rotation portion is symmetrical in shape and has a concave portion in a middle portion thereof, the second rotation portion is located in the concave portion, and the first axis coincides with a symmetry line of the first rotation portion.

9. The laser three-dimensional scanning measurement device of claim 1, wherein the measurement interferometer comprises a partially reflective assembly configured to receive the measurement beam and split the measurement beam into a first beam transmitted to the target via the partially reflective assembly and reflected by the target to form a first reflected beam, a polarizing module configured to adjust a polarization state of the measurement beam, and a collimating module cooperating with the partially reflective assembly for collimating the measurement beam; the detection assembly is further configured to obtain a distance between the partially reflective assembly and the target based on interference results of the first reflected light beam and the second light beam.

10. The laser three-dimensional scanning measurement device according to claim 2, wherein the fiber optic system further comprises an auxiliary interferometer, a fiber coupling assembly and an indication light source, wherein the frequency modulated laser light source, the detection assembly, the auxiliary interferometer, the fiber coupling assembly and the indication light source are connected through polarization maintaining fibers; the auxiliary interferometer generates an auxiliary measurement signal based on the measurement beam to achieve nonlinear correction of the frequency modulated laser light source; the optical fiber coupling assembly is configured to realize beam splitting or beam combination of the measuring light beam; the indication light source is used for generating an indication light beam to indicate the target, and the indication light beam is guided by the polarization maintaining fiber and coupled to the fiber optical path system by the fiber coupling component.