Laser radar measurement system with multiple measurement modes

Abstract

The invention relates to a multi-measurement-mode laser radar measurement system, which comprises a generation module, a distance measurement module, an attenuation module and an adjustment module, and is characterized in that the generation module is configured to emit a measurement light beam for detecting a target; the distance measuring module is configured to measure the target based on the measuring light beam reflected by the target; the attenuation module is configured to be coupleable between the ranging module and the adjustment module and to adjust the power of the measurement beam when coupled between the ranging module and the adjustment module. The adjustment module is configured to switch a mode for adjusting the morphology of the measurement beam based on a control signal for characterizing whether the attenuation module is coupled between the ranging module and the adjustment module. In this case, a multi-measurement-mode laser radar measurement system which adapts to various measurement scenes and improves the integration level can be provided.

Description

Technical Field

[0001] This disclosure relates to the field of intelligent manufacturing equipment industry, specifically to a multi-measurement mode lidar measurement system. Background Technology

[0002] LiDAR, as a novel high-precision measuring instrument, combines the advantages of optical interferometry and radar technology, and has significant application prospects in fields such as high-precision, large dynamic range environmental surveying. LiDAR achieves target measurement (e.g., measurement of information such as position, distance, and shape features) by emitting a measurement beam towards the target and receiving the reflected beam by photoelectric elements.

[0003] In existing technologies, to broaden the applicability of lidar, a multi-source and multi-path optical design is typically employed. For example, to enable lidar to measure both cooperative and non-cooperative targets, a dual-source and dual-path design is usually used in the internal optical system. Specifically, the optical system includes a cooperative light source for cooperative targets and a non-cooperative light source for non-cooperative targets, with separate cooperative and non-cooperative optical paths for measuring both. This allows for the measurement of both cooperative and non-cooperative targets.

[0004] Although this design can effectively improve the applicable scenarios of lidar, the dual-source and dual-optical-path design makes the lidar structure more complex and occupies more space. In addition, it also increases the manufacturing cost and maintenance difficulty of the optical path system. Summary of the Invention

[0005] This disclosure is made in view of the above circumstances, and its purpose is to provide a lidar measurement system with multiple measurement modes that can adapt to various measurement scenarios and improve integration.

[0006] To this end, this disclosure provides a multi-measurement mode lidar measurement system, the lidar measurement system including a generation module, a ranging module, an attenuation module, and an adjustment module. The generation module is configured to emit a measurement beam for detecting a target; the ranging module is configured to measure the target based on the measurement beam reflected by the target; the attenuation module is configured to be coupled between the ranging module and the adjustment module and is configured to adjust the power of the measurement beam when coupled between the ranging module and the adjustment module; the adjustment module is configured to switch modes for adjusting the shape of the measurement beam based on a control signal characterizing whether the attenuation module is coupled between the ranging module and the adjustment module.

[0007] In this disclosure, the generating module sends a measurement beam to the target, the ranging module obtains target information based on the measurement beam reflected by the target, and the attenuation module can be coupled to the propagation path of the measurement beam and configured to adjust the power of the measurement beam. The adjustment module can be configured to switch the mode of adjusting the shape of the measurement beam in accordance with the attenuation module. In this case, by cooperating with the propagation path of the measurement beam (e.g., coupled to the optical path or not coupled to the optical path), the power and shape of the emitted measurement beam can be adjusted, thereby enabling the measurement system to adapt to the measurement of various targets, thus enabling the measurement system to have multiple measurement modes.

[0008] Furthermore, in the multi-measurement mode lidar measurement system disclosed herein, optionally, the adjustment module includes a beam-expanding and collimation mode and a focusing mode. The adjustment module expands and collimates the measurement beam based on the beam-expanding and collimation mode, and adjusts the focusing position of the measurement beam based on the focusing mode. In this case, by adjusting the measurement beam to different shapes, the measurement beam can be adapted to various measurement scenarios, that is, the measurement system can measure various targets (e.g., cooperative targets and non-cooperative targets).

[0009] Furthermore, in the multi-measurement mode lidar measurement system disclosed herein, optionally, the adjustment module includes a first lens unit and a second lens unit. When the attenuation module is coupled between the ranging module and the adjustment module, the first lens unit and the second lens unit are fixed at a reference position for beam expansion and collimation of the measurement beam. When the attenuation module is not coupled between the ranging module and the adjustment module, the first lens unit can move relative to the second lens unit to adjust the focusing position of the measurement beam. In this case, the shape of the measurement beam can be adjusted by controlling the positions of the first lens unit and the second lens unit.

[0010] Furthermore, in the multi-measurement mode lidar measurement system disclosed herein, optionally, the generating module includes a measurement light source and an indicator light source. The measurement light source is configured to emit a measurement beam, and the indicator light source is configured to emit an indicator beam indicating the target. Thus, target detection can be achieved based on the measurement beam, and whether the measured area is the target can be determined based on the indicator beam. Simultaneously, the target can be visually observed through the indicator beam.

[0011] Additionally, in the multi-measurement mode lidar measurement system disclosed herein, optionally, a beam splitting module, a receiving module, and a processing module are also included. When the attenuation module is coupled between the ranging module and the adjustment module, the adjustment module is located between the attenuation module and the beam splitting module. The beam splitting module is configured to receive an indicator beam reflected by the target and reflect the indicator beam reflected by the target back to the receiving module. The processing module is configured to track the target based on the indicator beam received by the receiving module. Thus, the measurement system is capable of tracking the target.

[0012] Additionally, in the multi-measurement mode lidar measurement system disclosed herein, a monitoring module may optionally be included. This monitoring module is configured to receive the indicator beam emitted by the indicator light source and control the output power of the indicator light source based on the power of the received indicator beam. In this case, by monitoring the power of the indicator beam through the monitoring module, the monitoring module and the indicator light source can form a negative feedback mechanism to control the output power of the indicator light source in real time. This helps to maintain the stability of the indicator beam's power, and further, it helps to maintain the stability of the power of the indicator beam reflected by the target, thereby improving the tracking performance of the measurement system.

[0013] In addition, in the multi-measurement mode lidar measurement system disclosed herein, optionally, a receiving module and a processing module are also included. When the attenuation module is not coupled between the ranging module and the adjustment module, the receiving module is configured to acquire an image of the target, and the processing module is configured to plan a scanning path for scanning the target based on the image of the target. In this case, the processing module can plan the scanning path for the target from an "equivalent to the actual measurement perspective," and the measurement system can directly scan the target according to the scanning path planned by the processing module, which is beneficial to improving the scanning efficiency and accuracy of the measurement system for the target. In addition, in the multi-measurement mode lidar measurement system disclosed herein, optionally, an acquisition module is also included. The acquisition module includes a first acquisition unit and a second acquisition unit disposed on both sides of the propagation path of the measurement beam. The first acquisition unit includes a first light source for emitting a first beam and a first imaging unit for receiving the first beam reflected by the target to obtain a first light spot. The second acquisition unit includes a second light source for emitting a second beam and a second imaging unit for receiving the second beam reflected by the target to obtain a second light spot. The acquisition module acquires the target based on the first light spot and the second light spot. Therefore, it is possible to recapture a target after it has been lost, and to track the target after it has been captured.

[0014] In addition, in the multi-measurement mode lidar measurement system disclosed herein, optionally, the ranging module includes a first polarization beam splitter, a modulation unit, a second polarization beam splitter, a partial reflection unit, and a first detection unit. The first polarization beam splitter is configured to split the measurement beam into two sub-measurement beams. The modulation unit is disposed between the first polarization beam splitter and the second polarization beam splitter and configured to perform anti-phase modulation on the two sub-measurement beams. The second polarization beam splitter is configured to couple the two anti-phase modulated sub-measurement beams as measurement beams. The partial reflection unit is configured to receive the measurement beam coupled through the second polarization beam splitter and reflect a portion of the measurement beam as a reference beam, and transmit another portion of the measurement beam as a target beam, the target beam being configured to be emitted to a target. The first detection unit is coupled to the optical path between the second coupling unit and the partial reflection unit and configured to receive the reference beam and the target beam reflected by the target. In this scenario, the target beam and the reference beam can share a common output and receiving optical path. This allows the measurement error caused by environmental changes to be converted into a common-mode signal when calculating the target distance. The common-mode signal can then be canceled out by differential modulation, thereby improving the accuracy of the target measurement. Furthermore, by inverting the two sub-measurement beams, distance measurement can be achieved using each sub-measurement beam separately. This allows for the acquisition of Doppler frequency shift and distance measurement in a short time, reducing measurement time.

[0015] Furthermore, in the multi-measurement-mode lidar measurement system disclosed herein, the target may optionally include at least one of a cooperative target matched with the beam-expanding and collimation mode and a non-cooperative target matched with the focusing mode. Thus, it is possible to measure cooperative targets based on the beam-expanding and collimation mode and non-cooperative targets based on the focusing mode.

[0016] According to this disclosure, a multi-measurement mode lidar measurement system that can adapt to various measurement scenarios and improve integration can be provided. Attached Figure Description

[0017] This disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings, in which...

[0018] Figure 1 This is a diagram illustrating an application scenario of the measurement system involved in the examples of this disclosure.

[0019] Figure 2 This is a block diagram illustrating the structure of the measurement system described in this disclosure example.

[0020] Figure 3 This is a block diagram illustrating the structure of the generation module involved in the example of this disclosure.

[0021] Figure 4 This is a schematic diagram illustrating the optical path principle of the ranging module involved in the example of this disclosure.

[0022] Figure 5 This is a schematic diagram illustrating the optical path principle of the measurement system involved in the example of this disclosure.

[0023] Figure 6 This is a simplified schematic diagram illustrating the structure of the adjustment module involved in the example of this disclosure.

[0024] Figure 7 This is a schematic diagram of the optical path structure of the cooperative measurement mode involved in the example of this disclosure.

[0025] Figure 8 This is a schematic diagram of the optical path structure of the non-cooperative measurement mode involved in the example of this disclosure.

[0026] Figure 9 This is a schematic diagram illustrating a first embodiment of the optical path structure of the ranging module involved in the example of this disclosure.

[0027] Figure 10 This is a schematic diagram illustrating a second embodiment of the optical path structure of the ranging module involved in the example of this disclosure. Detailed Implementation

[0028] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same components, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the components or the shapes of the components may differ from actual figures.

[0029] Furthermore, the subheadings and similar terms used in the following description of this disclosure are not intended to limit the content or scope of this disclosure; they are merely intended to serve as reading prompts. Such subheadings should not be construed as dividing the content of the article, nor should the content under a subheading be limited to the scope of that subheading.

[0030] This disclosure relates to a multi-measurement mode lidar measurement system, which may be simply referred to as a lidar measurement system, lidar, or measurement system. The measurement system disclosed herein can be used to measure targets, for example, to measure information such as the target's distance, position, orientation, velocity, attitude, and shape.

[0031] In some examples, "multiple measurement modes" refers to the measurement system of this disclosure having multiple measurement modes (described in detail later). This allows it to be applied to a variety of measurement scenarios. In some examples, the measurement system of this disclosure is also suitable for applications involving target identification and tracking.

[0032] The multi-measurement mode lidar measurement system disclosed herein can also be referred to as a multi-measurement mode measurement system, a lidar measurement system with non-cooperative target measurement and cooperative target measurement capabilities, etc. The target measurement described in this disclosure can also be referred to as target detection, target scanning, target monitoring, etc. The following detailed description of this disclosure is provided with reference to the accompanying drawings.

[0033] Figure 1 This is a diagram illustrating an application scenario of the measurement system 1 involved in the example of this disclosure.

[0034] In some examples, measurement system 1 may measure target 2 based on a measurement beam L emitted to target 2. Specifically, see [link to documentation]. Figure 1 Measurement system 1 can emit a measurement beam L to target 2. Target 2 receives the measurement beam L and reflects it back to measurement system 1. Measurement system 1 can then measure target 2 based on the measurement beam L reflected by target 2. In some examples, measurement system 1 can be a measuring instrument such as a lidar, laser tracker, or laser scanner.

[0035] In some examples, target 2 may include a cooperative target. A cooperative target can refer to a reflective device used in conjunction with measurement system 1. In some examples, the cooperative target can be located on the target to be measured. Thus, information from the measured cooperative target can be used as information about the target to be measured. In some examples, when target 2 is a cooperative target, the corresponding measurement mode in measurement system 1 can be called a cooperative measurement mode.

[0036] In some examples, target 2 may include a non-cooperative target. A non-cooperative target can refer to the target to be measured itself. Therefore, information about the target to be measured can be directly measured. In some examples, when target 2 is a non-cooperative target, the corresponding measurement mode in measurement system 1 can be called a non-cooperative measurement mode.

[0037] In some examples, objective 2 may include at least one of cooperative and non-cooperative objectives.

[0038] In some examples, the cooperative target may have a retroreflector, which can provide a high reflectivity for the cooperative target. Therefore, when target 2 is a cooperative target, in order to reduce the excessive power of the backlight of the measurement beam L reflected by target 2, which could lead to oversaturation of the backlight signal and consequently measurement errors, the power of the measurement beam L emitted by measurement system 1 is usually controlled to a low range. In this case, the signal-to-noise ratio of the measurement beam L reflected by target 2 can be improved, and the signal-to-noise ratio can be kept within a measurable range, thereby improving the measurement accuracy of measurement system 1.

[0039] In some examples, non-cooperative targets diffusely reflect the measurement beam L, resulting in low reflectivity. Therefore, when target 2 is a non-cooperative target, to reduce the risk of weak reflected signals and measurement errors due to excessively low backlight power of the measurement beam L reflected by target 2, the power of the measurement beam L emitted by measurement system 1 is typically controlled within a higher range. In this case, increasing the backlight power of the measurement beam L reflected by target 2 increases the detection range of measurement system 1. Furthermore, high backlight power improves the resistance of the backlight signal to interference from the external environment, thereby improving the signal-to-noise ratio of the backlight signal and ultimately enhancing the measurement accuracy of measurement system 1.

[0040] See in some examples Figure 1 The measurement system 1 may include a measurement host 10. The measurement host 10 may include an exit window 11 for emitting the measurement beam L.

[0041] In some examples, the measurement system 1 may include a rotating axis for controlling the movement of the measurement host 10. In some examples, the rotating axis may include a first rotating axis and a second rotating axis, the first rotating axis controlling the horizontal rotation of the measurement host 10 and the second rotating axis controlling the pitch rotation of the measurement host 10. In this case, by cooperating with the first and second rotating axes, the measurement host 10 can be controlled to rotate in any direction, thereby enabling flexible control of the emission direction of the measurement beam L.

[0042] Figure 2 This is a block diagram illustrating the structure of the measurement system 1 as described in this disclosure example. Figure 3 This is a block diagram illustrating the structure of the generation module 20 as described in this disclosure example.

[0043] See in some examples Figure 2 The measurement system 1 may include a generating module 20 and a ranging module 30. In some examples, the generating module 20 may be configured to emit a measurement beam L for detecting a target 2. After being emitted to the target 2, the measurement beam L may be reflected back to the measurement system 1 by the target 2.

[0044] See in some examples Figure 3 The generating module 20 may include a measurement light source 21, which can be configured to emit a measurement beam L. Thus, the target 2 can be detected based on the measurement beam L.

[0045] In some examples, the measurement light source 21 can be a laser source, and the measurement beam L can be a laser beam. In some examples, the measurement beam L can be a pulsed laser. In other examples, the measurement beam L can be broadband light, such as a superradiative laser.

[0046] In some examples, the measurement light source 21 can be a frequency-modulated laser source, and the measurement beam L can be a linearly frequency-modulated continuous laser. In this case, since the distance to the target 2 causes the frequency of the measurement beam L reflected back to the measurement system 1 to change relative to the frequency of the reference beam L2 (described later), the distance to the target 2 can be calculated by measuring this frequency change.

[0047] Furthermore, if target 2 has velocity, the frequency of the reflected measurement beam L is also affected by the Doppler effect. The frequency difference includes the intermediate frequency component corresponding to the distance to target 2 and the frequency shift component caused by the Doppler effect (referred to as Doppler shift). The Doppler shift affects the measurement accuracy of target 2, but the Doppler shift can be easily obtained by inverting the linear frequency modulated continuous wave. In this case, the intermediate frequency component corresponding to the distance to target 2 can be easily obtained based on the frequency difference and the Doppler shift, thereby improving the measurement accuracy.

[0048] See in some examples Figure 3 The generating module 20 may include an indicator light source 22, which may be configured to emit an indicator beam. In some examples, the indicator beam may be used to indicate a target 2. Indicating a target 2 can be understood as being able to visually observe the light spot formed after the indicator beam is emitted onto the target 2. Thus, it is possible to determine whether the area being measured is the target based on the indicator beam, and at the same time, it is also possible to visually observe the target 2 through the indicator beam.

[0049] In some examples, the indicator light source 22 can be a laser light source, and the indicator beam can be a laser beam. In some examples, the indicator beam can be a visible light beam.

[0050] In some examples, the indicator beam and the measurement beam L can be coupled and simultaneously emitted to the target 2. In this case, the synchronization between the measured target 2 and the indicated target 2 can be improved, that is, the indicated target 2 is the same as the measured target 2, thereby improving the consistency between observation and measurement.

[0051] Figure 4 This is a schematic diagram illustrating the optical path principle of the ranging module 30 involved in the example of this disclosure.

[0052] in, Figure 4 Target 2 in the text has been simplified. Figure 4 The solid arrow indicates the emitted measurement beam L, and the dashed arrow indicates the measurement beam L that is reflected (e.g., reflected by the partial reflection unit 301 and / or reflected by the target 2).

[0053] In some examples, the measuring light source 21 emits a measuring beam L, which can be emitted to the target 2 after passing through the ranging module 30. In some examples, the ranging module 30 can be configured to measure the target 2 based on the measuring beam L reflected by the target 2. Thus, information about the target 2 can be measured.

[0054] See in some examples Figure 4 The ranging module 30 may include a partial reflection unit 301 and a first detection unit 302. In some examples, the partial reflection unit 301 may be configured to transmit and reflect a partial measurement beam L, wherein the transmitted partial measurement beam L may be emitted to the target 2, and the reflected partial measurement beam L may be received by the first detection unit 302. Then, the partial measurement beam L emitted to the target 2 is reflected by the target 2 and returns to the first detection unit 302 of the ranging module 30. The first detection unit 302 may obtain information about the target 2 based on the partial measurement beam L reflected by the partial reflection unit 301 and the partial measurement beam L reflected by the target 2.

[0055] See in some examples Figure 4 The ranging module 30 may include a first coupling unit 303. The first detection unit 302 can be coupled to the measurement optical path of the ranging module 30 through the first coupling unit 303.

[0056] Figure 5 This is a schematic diagram illustrating the optical path principle of the measurement system 1 involved in the example of this disclosure.

[0057] in, Figure 5 The solid arrow indicates the emitted measurement beam L, the dashed arrow indicates the measurement beam L reflected by the target 2, and the hollow dashed arrow indicates that the attenuation module 50 can be coupled into the optical path.

[0058] See in some examples Figure 2 or Figure 5 The measurement system 1 may also include an adjustment module 40. In some examples, the adjustment module 40 can be used to adjust the shape of the measurement beam L. In this case, by adjusting the measurement beam L to different shapes, the measurement beam L can be adapted to various measurement scenarios, that is, the measurement system 1 can measure various targets 2 (e.g., cooperative targets and non-cooperative targets).

[0059] In some examples, the adjustment module 40 may include a collimation mode. In some examples, the adjustment module 40 may collimate the measurement beam L based on the collimation mode. In other words, the adjustment module 40 may adjust the shape of the measurement beam L to a collimated shape.

[0060] In some examples, the adjustment module 40 may include a beam-expanding mode. In some examples, the adjustment module 40 may expand the measurement beam L based on the beam-expanding mode. In other words, the adjustment module 40 may adjust the shape of the measurement beam L to an expanded shape.

[0061] In some examples, the adjustment module 40 may include a beam-expanding collimation mode. In some examples, the cooperative target may be matched with the beam-expanding collimation mode. Thus, the cooperative target can be measured based on the beam-expanding collimation mode.

[0062] In some examples, the adjustment module 40 can expand and collimate the measurement beam L based on the beam expansion and collimation mode. In other words, the adjustment module 40 can adjust the shape of the measurement beam L to a beam expansion and collimation shape. In this case, since the cooperative target has a high reflectivity, when the measurement system 1 uses the measurement beam L in a beam expansion and collimation shape, it can be used to measure the cooperative target.

[0063] In some examples, the adjustment module 40 may include a focus mode. In some examples, a non-cooperative target may be matched with a focus mode. Thus, it is possible to measure the non-cooperative target based on the focus mode.

[0064] In some examples, the adjustment module 40 can focus the measurement beam L based on a focusing mode. In other words, the adjustment module 40 can adjust the shape of the measurement beam L to a focused shape. In this case, since the non-cooperative target has low reflectivity, the measurement system 1 can be used to measure non-cooperative targets when the measurement beam L is in a focused shape.

[0065] In some examples, the adjustment module 40 can adjust the focus position of the measurement beam L based on the focusing mode. In this case, when the target 2 being measured moves or different targets 2 are measured, the adjustment module 40 adjusts the focus position of the measurement beam L to always focus the measurement beam L on the target 2. In other words, the focus position of the measurement beam L can always be kept on the target to be measured, thereby improving the measurement accuracy and measurement efficiency of the measurement system 1.

[0066] Figure 6 This is a simplified schematic diagram illustrating the structure of the adjustment module 40 involved in the example of this disclosure.

[0067] See in some examples Figure 6 The adjustment module 40 may include at least one lens unit 41. In some examples, the shape of the measurement beam L can be adjusted by one lens unit 41. In some examples, the shape of the measurement beam L can be adjusted by multiple lens units 41.

[0068] See in some examples Figure 6The adjustment module 40 may include a first lens unit 41a and a second lens unit 41b. In some examples, the first lens unit 41a and the second lens unit 41b may be fixed in place.

[0069] In some examples, the first lens unit 41a and the second lens unit 41b can move relative to each other. In this case, the shape of the measurement beam L can be adjusted by controlling the relative position change of the first lens unit 41a and the second lens unit 41b.

[0070] As described above, the adjustment module 40 can expand and collimate the measurement beam L. In some examples, the adjustment module 40 can expand and collimate the measurement beam L when the first lens unit 41a and the second lens unit 41b are fixed at a reference position. In other words, in the beam expansion and collimation mode, the first lens unit 41a and the second lens unit 41b can be located at the reference position and remain fixed. In some examples, the reference position can be a pre-calibrated position.

[0071] As described above, the adjustment module 40 can adjust the focus position of the measurement beam L. In some examples, the focus position of the measurement beam L can be adjusted by changing the distance between the first lens unit 41a and the second lens unit 41b. In other words, in focusing mode, the first lens unit 41a can be moved relative to the second lens unit 41b to adjust the focus position of the measurement beam L.

[0072] In some examples, the second lens unit 41b can be fixed, while the first lens unit 41a can move along the path of the measurement beam L. This allows the distance between the first lens unit 41a and the second lens unit 41b to be changed.

[0073] In some examples, the first lens unit 41a can be fixed, while the second lens unit 41b can move along the path of the measurement beam L. This allows the distance between the first lens unit 41a and the second lens unit 41b to be changed.

[0074] See in some examples Figure 6 The adjustment module 40 may also include a grating ruler 42. In some examples, the movement of the first lens unit 41a can be measured by the grating ruler 42. This improves the movement accuracy of the first lens unit 41a.

[0075] In some examples, adjustment module 40 can work in conjunction with attenuation module 50 to adjust the shape of the measurement beam L.

[0076] See in some examples Figure 2 or Figure 5The measurement system 1 may also include an attenuation module 50. In some examples, the attenuation module 50 may be configured to be coupled into the propagation path of the measurement beam L. In some examples, when the attenuation module 50 is coupled into the propagation path of the measurement beam L, the attenuation module 50 may be configured to adjust the power of the measurement beam L. In this case, by cooperating with the propagation path of the measurement beam L (e.g., coupled into the optical path or not coupled into the optical path), the power of the emitted measurement beam L can be adjusted, thereby enabling the measurement system 1 to adapt to the measurement of various targets 2, thus enabling the measurement system 1 to have multiple measurement modes.

[0077] In some examples, the attenuation module 50 is configured to be coupled into the propagation path of the measurement beam L. This can be understood as the attenuation module 50 being located in the propagation path of the measurement beam L, or the attenuation module 50 not being located in the propagation path of the measurement beam L. In this case, the measurement system 1 can detect different targets 2 (e.g., cooperative or non-cooperative targets) depending on whether the attenuation module 50 is coupled into the propagation path of the measurement beam L, or automatically couple or decouple the attenuation module 50 into the propagation path of the measurement beam L depending on the different targets 2 being measured (e.g., cooperative or non-cooperative targets). This improves the applicability and measurement efficiency of the measurement system 1.

[0078] In some examples, the attenuation module 50 can be configured to be coupled between the ranging module 30 and the adjustment module 40. In some examples, when the attenuation module 50 is configured to be coupled between the ranging module 30 and the adjustment module 40, the attenuation module 50 can adjust the power of the measurement beam L. In some examples, the attenuation module 50 can reduce the power of the measurement beam L. In this case, the power of the measurement beam L emitted by the measurement system 1 can be kept in a lower range, thereby enabling the measurement system 1 to be adapted to measure cooperative targets.

[0079] In some examples, the attenuation module 50 may include at least one of a filter, a diffuser, a diffuser, and an optical attenuator. In some examples, the attenuation module 50 may reduce the power of the measurement beam L by absorbing or scattering a portion of the beam's energy.

[0080] As described above, the attenuation module 50 can cooperate with the adjustment module 40 to adjust the shape of the measurement beam L. In some examples, the adjustment module 40 can be configured to switch the mode for adjusting the shape of the measurement beam L based on a control signal. In some examples, the mode for adjusting the shape of the measurement beam L may include the aforementioned beam expansion and collimation mode and focusing mode. Thus, the measurement system 1 can change the measurement mode in real time according to measurement requirements.

[0081] In some examples, the control signal described above can characterize whether the attenuation module 50 is coupled between the ranging module 30 and the adjustment module 40. In this case, the adjustment module 40 can switch modes according to the control signal indicating whether the attenuation module 50 is coupled between the ranging module 30 and the adjustment module 40, thereby enabling the measurement beam L emitted by the measurement system 1 to be adapted to the measurement of various targets 2, that is, enabling the measurement system 1 to have multiple measurement modes.

[0082] In some examples, when the attenuation module 50 is coupled between the ranging module 30 and the adjustment module 40, the adjustment module 40 can switch to a beam-expanding and collimating mode. In some examples, when the attenuation module 50 is coupled between the ranging module 30 and the adjustment module 40, the first lens unit 41a and the second lens unit 41b can be fixed at a reference position for beam-expanding and collimating the measurement beam L. In this case, the attenuation module 50 reduces the power of the measurement beam L, and the adjustment module 40 expands and collimates the measurement beam L. Through the cooperation of the attenuation module 50 and the adjustment module 40, the power of the measurement beam L can be further reduced to a lower range, thereby facilitating the measurement of the cooperative target using the measurement beam L with a beam-expanding and collimating configuration.

[0083] In some examples, when the attenuation module 50 is configured not to be coupled between the ranging module 30 and the adjustment module 40, the power of the measurement beam L emitted by the measurement system 1 can be in a higher range. Therefore, the measurement system 1 can be adapted to measure non-cooperative targets.

[0084] In some examples, when the attenuation module 50 is not coupled between the ranging module 30 and the adjustment module 40, the adjustment module 40 can switch to a focusing mode. In some examples, when the attenuation module 50 is not coupled between the ranging module 30 and the adjustment module 40, the first lens unit 41a can move relative to the second lens unit 41b to adjust the focusing position of the measurement beam L. In this case, the adjustment module 40 focuses the measurement beam L, enabling the power of the measurement beam L to be in a higher range. This is beneficial for measuring non-cooperative targets using the measurement beam L with a focused shape. In addition, by adjusting the focusing position of the measurement beam L by the adjustment module 40, the focusing position of the measurement beam L can always fall on the target 2, thereby improving the measurement accuracy of non-cooperative targets.

[0085] Figure 7 This is a schematic diagram of the optical path structure of the cooperative measurement mode involved in the example of this disclosure. As described above, the generating module 20 includes an indicator beam for emitting an indicator beam. In some examples, the indicator beam may be coupled to the measurement beam L in the ranging module 30, and together with the measurement beam L, be emitted to the target 2 and reflected back to the measurement system 1 by the target 2.

[0086] In some examples, the measurement system 1 can also track the target 2 based on the indicator beam. In this case, it can continuously detect the target 2 and acquire information on the changes of the target 2 in time and space, which is beneficial for monitoring the movement, shape changes and other actions of the target 2; in addition, it can focus on scanning the target 2 during continuous scanning, reducing interference from non-target data.

[0087] See in some examples Figure 7 In the cooperative measurement mode, target 2 can be a cooperative target, and adjustment module 40 can expand and collimate the measurement beam L.

[0088] See in some examples Figure 7 The measurement system 1 may include a receiving module 60. The receiving module 60 can receive an indicator beam reflected by the target 2. In some examples, the measurement system 1 may also include a processing module. In some examples, the processing module can be communicatively connected to the receiving module 60. In some examples, the processing module can track the target 2 based on the signal received by the receiving module 60. In some examples, the processing module may also be called a tracking module. See also... Figure 7 The measurement system 1 may also include a beam splitting module 70. The beam splitting module 70 can be used to adjust the propagation direction of the indicator beam reflected by the target 2.

[0089] See in some examples Figure 7 The adjustment module 40 can be located between the attenuation module 50 and the beam splitting module 70. In other words, the beam splitting module 70 can be located on the side of the adjustment module 40 relative to the attenuation module 50. In this case, the beam splitting module 70 can receive the indicator beam reflected by the target 2 to the maximum extent and reflect it to the receiving module 60, thereby facilitating subsequent improvement of tracking accuracy.

[0090] In some examples, when the attenuation module 50 is coupled between the ranging module 30 and the adjustment module 40, the beam splitting module 70 can be configured to receive the indicator beam reflected by the target 2 and reflect the indicator beam reflected by the target 2 to the receiving module 60. The processing module can be configured to track the target 2 based on the indicator beam received by the receiving module 60. Thus, the measurement system 1 is able to track the target 2.

[0091] In some examples, the receiving module 60 can be configured to receive the indicator beam reflected by the target 2 and generate an indicator spot. In some examples, the receiving module 60 can perform pattern processing on the indicator spot and send the patterned indicator spot to the processing module. Thus, the processing module can track the target 2 based on the patterned indicator spot.

[0092] In some examples, the receiving module 60 may be an image sensor, such as a CMOS camera. In some examples, the receiving module 60 may perform grayscale processing on the indicator spot. In some examples, the receiving module 60 may perform binarization processing on the indicator spot.

[0093] In some examples, the receiving module 60 can perform grayscale processing and binarization on the indicator spot. In this case, the visibility of the indicator spot can be enhanced, thereby improving the accuracy of feature extraction (e.g., centroid) of the indicator spot.

[0094] In some examples, the receiving module 60 can perform centroid detection on the indicator spot. In this case, the coordinates of the centroid of the indicator spot on the receiving module 60 (hereinafter referred to as spot coordinates for ease of description) can be obtained, and the processing module can then track the target 2 based on the spot coordinates.

[0095] In some examples, the beam coordinates can be recorded, and the processing module can provide servo control feedback information based on the recorded beam coordinates. In this case, when the target 2 moves, the processing module can provide servo control feedback information to the mechanism for controlling the rotation axis. The mechanism for controlling the rotation axis drives the rotation axis to rotate based on the servo control feedback information to change the emission direction of the measurement beam L and the indicator beam. Thus, the emission directions of the indicator beam and the measurement beam L can change with the movement of the target 2 and always face the target 2, thereby enabling the tracking of the target 2.

[0096] See in some examples Figure 7 The measurement system 1 may also include a monitoring module 80. In some examples, the monitoring module 80 may be configured to receive the indicator beam emitted by the indicator light source. In some examples, the monitoring module 80 may be configured to receive the indicator beam and obtain its power. In this case, the monitoring module 80 can determine whether the output power of the indicator light source 22 is stable based on the obtained power of the indicator beam.

[0097] As described above, the measurement system 1 can track the target 2 based on the indicator beam reflected by the target 2. In order for the measurement system 1 to have high tracking performance, the indicator beam reflected by the target 2 needs to have high stability.

[0098] In some examples, the power of the indicator beam reflected by the target 2 can be kept stable by controlling the stability of the power of the indicator beam emitted by the measurement system 1. When the output power of the indicator light source 22 is stable, the power of the indicator beam emitted by the measurement system 1 can remain stable, and consequently, the power of the indicator beam reflected by the target 2 can have the same stability. In this case, the control accuracy of the servo control system of the measurement system 1 can be improved, and the tracking performance of the target 2 can be enhanced.

[0099] In some examples, the monitoring module 80 can be configured to control the output power of the indicator light source 22 based on the power of the received indicator beam. In this case, by monitoring the power of the indicator beam through the monitoring module 80, the monitoring module 80 and the indicator light source 22 can form a negative feedback mechanism to control the output power of the indicator light source 22 in real time, which helps to maintain the stability of the power of the indicator beam. Furthermore, it can maintain the stability of the power of the indicator beam reflected by the target 2, thereby improving the tracking performance of the measurement system 1.

[0100] In some examples, the monitoring module 80 and the indicator light source 22 can form a negative feedback mechanism, meaning that, for example, when the monitoring module 80 detects that the power of the indicator beam is high, the monitoring module 80 transmits feedback information to the indicator light source 22 in real time, and the indicator light source 22 reduces its output power based on the received feedback information. In some examples, the output power of the indicator light source 22 can be controlled by controlling the current in the indicator light source 22.

[0101] In some examples, the monitoring module 80 can be positioned opposite the receiving module 60. Specifically, the monitoring module 80 and the receiving module 60 can be respectively positioned on opposite sides of the beam splitter 70. In this case, the optical path structure is simplified while the integration of the measurement system is improved. However, the disclosure is not limited to this; the positions of the monitoring module 80 and the receiving module 60 are not restricted as long as they can perform their corresponding functions.

[0102] In some examples, the beam splitter 70 can be configured to receive a portion of the indicator beam via the adjustment module 40 and transmit the indicator beam to the target 2. This enables the indication of the target 2. In some examples, the beam splitter 70 can be configured to receive the indicator beam via the adjustment module 40 and reflect a portion of the indicator beam to the monitoring module 80. This enables the monitoring of the output power of the indicator light source 22 based on a portion of the indicator beam.

[0103] In some examples, the receiving module 60 may also be integrated into the processing module. In other words, in some examples, the processing module may receive the indicator beam and track the target 2 based on the received indicator beam.

[0104] See in some examples Figure 7The measurement system 1 may also include an acquisition module 90. In some examples, the measurement system 1 can identify the target 2 based on the acquisition module 90, and then track the target 2 based on the processing module. When the measurement system 1 loses tracking of the target 2, it can re-identify the target 2 through the acquisition module 90. In this case, the measurement system 1 can re-aime at the target 2 based on the acquisition module 90 and achieve tracking of the target 2. In some examples, the aforementioned "aiming" may refer to the measurement beam L and the indicator beam being aligned with the target 2; in other words, the measurement beam L and the indicator beam being emitted towards the target 2.

[0105] In some examples, the capture module 90 may include at least one capture unit. The at least one capture unit may be located near the exit window 11. In some examples, the optical elements and structural arrangements in the individual capture units of the at least one capture unit may be identical. See also [link to example 1]. Figure 7 The capture module 90 may include two capture units, such as a first capture unit 91 and a second capture unit 92. In some examples, the first capture unit 91 and the second capture unit 92 may be respectively disposed on both sides of the propagation path of the measurement beam L. In some examples, the first capture unit 91 and the second capture unit 92 may be respectively disposed on both sides of the exit window 11.

[0106] In some examples, the first acquisition unit 91 may include a first light source 911 for emitting a first light beam and a first imaging unit 912 for receiving the first light beam reflected by the target 2 to obtain a first light spot.

[0107] In some examples, the second capturing unit 92 may include a second light source 921 for emitting a second beam and a second imaging unit 922 for receiving the second beam reflected by the target 2 to obtain a second light spot.

[0108] In some examples, the acquisition module 90 can acquire the target 2 based on the first light spot and the second light spot. This enables the measurement system 1 to reacquire the target 2 after losing it, and to track the target 2 after acquisition.

[0109] In some examples, the first light source 911 and the second light source 921 can be diffuse light sources. In this case, the first light source 911 and the second light source 921 have a large radiation range, that is, the capture module 90 can have a large field of view, thereby facilitating the identification of the target 2.

[0110] In some examples, the first light source 911 and the second light source 921 can be infrared LED light sources. In some examples, the first acquisition unit 91 may also include a lens coaxially arranged with the first imaging unit 912, and the second acquisition unit 92 may also include a lens coaxially arranged with the second imaging unit 922. In this case, the sharpness of the first and second light spots can be improved, thereby enabling the subsequent acquisition of the centroids of the first and second light spots with higher accuracy. In some examples, the target 2 can be acquired based on the centroids of the first and second light spots.

[0111] In some examples, the capture module 90 may include a capture unit. The capture module 90 can capture the target 2 based on a spot obtained by a capture unit. This simplifies the structural design of the measurement system 1.

[0112] Figure 8 This is a schematic diagram of the optical path structure of the non-cooperative measurement mode involved in the example of this disclosure.

[0113] In the non-cooperative measurement mode disclosed herein, the measurement light source 21 emits a measurement beam L, which is then transmitted to the target 2 sequentially via the ranging module 30 and the adjustment module 40. The attenuation module 50 is not coupled to the measurement optical path (see [link to relevant documentation]). Figure 8 ).

[0114] See in some examples Figure 8 In the non-cooperative measurement mode, target 2 can be a non-cooperative target, and adjustment module 40 can focus the measurement beam L. Adjustment module 40 can adjust the focus position of measurement beam L based on the focusing mode.

[0115] In some examples, the focusing position of the measurement beam L can be adjusted using pre-calibrated calibration data. This improves the measurement efficiency of the measurement system 1.

[0116] In some examples, pre-calibrated calibration data can be obtained based on the correlation between the positions of the multiple lens units 41 and the focal position of the measurement beam L. Specifically, multiple sets of calibration data can be obtained through multiple experiments. The calibration data may include the positions of the multiple lens units 41 and the focal position of the measurement beam L that matches the aforementioned positions.

[0117] In some examples, calibration tables or calibration curves can be generated based on multiple sets of calibration data. During the measurement of target 2, the focusing coordinate position of lens unit 41 can be obtained from the calibration table or calibration curve, and lens unit 41 can be controlled to quickly move to the focusing coordinate position. The focusing coordinate position refers to the position of each lens unit 41 (e.g., if the second lens unit 41b is fixed, then it refers to the first lens unit 41a) when the focusing position of the measurement beam L falls on target 2. This improves measurement efficiency.

[0118] In some examples, the measurement system 1 can obtain the preliminary position of the target 2 through preliminary measurement, and obtain the focused coordinate position based on the preliminary position and a calibration table or calibration curve. In some examples, after the lens unit 41 moves to the focused coordinate position, the lens unit 41 can be controlled to move within a preset range to find the position of the lens unit 41 when the reflected light intensity is maximum, which is used as the measurement position.

[0119] In some examples, the measurement system 1 can measure the target 2 when the lens unit 41 is in the measurement position. This improves measurement accuracy.

[0120] In some examples, the function of the receiving module 60 in the non-cooperative measurement mode may differ from that in the cooperative measurement mode. Similarly, in some examples, the function of the processing module in the non-cooperative measurement mode may differ from that in the cooperative measurement mode. In some examples, when the attenuation module 50 is not coupled between the ranging module 30 and the adjustment module 40, the receiving module 60 can be configured to acquire an image of the target 2, and the processing module can be configured to plan a scanning path for the target 2 based on that image. In this case, the processing module can plan the scanning path for the target 2 from an "equivalent actual measurement perspective," and the measurement system 1 can directly scan the target 2 according to the scanning path planned by the processing module, which is beneficial for improving the scanning efficiency and accuracy of the measurement system 1 for the target 2. In some examples, in the non-cooperative measurement mode, the receiving module 60 may also be referred to as an overview camera.

[0121] In some examples, the receiving module 60 can be integrated into the processing module. In other words, the processing module can simultaneously acquire an image of the target 2 and plan the scan path for the target 2. In some examples, the processing module can simultaneously have tracking and scan path planning functions. This further improves measurement efficiency.

[0122] In some examples, target 2 can be divided into multiple regions based on an image of target 2, and at least one signal focus can be matched for each region. Here, "dividing" refers to dividing target 2 into multiple regions using multiple virtual boundaries, and the signal focus can be a measurement point that needs to be focused on when measurement system 1 scans the current region. In some examples, the signal focus can be located on target 2.

[0123] In some examples, the measurement system 1 can sequentially focus on the signal focus of each region to obtain scan data for each region; and obtain scan data for the target 2 based on the scan data of each region. In this case, by dividing the target 2 into multiple regions and matching at least one signal focus for each region, when scanning each region, the measurement system 1 only needs to focus on the signal focus of the current region without focusing on every point on the target 2. This reduces the number of focusing operations of the measurement system 1, thereby improving the scanning efficiency of the measurement system 1.

[0124] In some examples, each region may include at least one sub-region corresponding to the signal focus. After the measurement system 1 focuses on the signal focus of the sub-region, the measurement system 1 can continuously scan the current sub-region and obtain a continuous feedback signal.

[0125] In some examples, there may be a signal range along the propagation direction of the measurement beam L that matches the signal focus. The signal range may be a distance range, and the signal focus may be located within the signal range.

[0126] In some examples, when each region is located within the signal range, the measurement system 1 can obtain a strong feedback signal. In this case, once the focusing position of the measurement beam L is focused on the signal focal point, scanning of each region can begin. At this time, each measurement point within the region can feed back a strong feedback signal to the measurement system 1. Thus, the complete signal of target 2 can be obtained without focusing the measurement beam L on each measurement point of target 2, improving measurement efficiency and speed.

[0127] In some examples, the matching principle for matching signal focus for each region can be: the signal range of each region can cover all measurement points in each region, that is, all measurement points in each region are located within the signal range.

[0128] In some examples, the functionality of other modules can be the same in non-cooperative measurement mode as in cooperative measurement mode, which will not be elaborated here.

[0129] In this disclosure, the generating module 20 sends a measurement beam L to the target 2, the ranging module 30 obtains information about the target 2 based on the measurement beam L reflected by the target 2, the attenuation module 50 can be coupled into the propagation path of the measurement beam L and configured to adjust the power of the measurement beam L, and the adjustment module 40 can be configured to switch the mode of adjusting the shape of the measurement beam L in conjunction with the attenuation module 50. In this case, by cooperating with the propagation path of the measurement beam L (e.g., coupled into the optical path or not coupled into the optical path), the power and shape of the emitted measurement beam L can be adjusted, thereby enabling the measurement system 1 to adapt to the measurement of various targets 2, thus enabling the measurement system 1 to have multiple measurement modes.

[0130] In this disclosure, the measurement system 1 can include a cooperative measurement mode and a non-cooperative measurement mode. Both modes share the same measurement light source 21 and the same measurement optical path. Different measurement modes can be achieved by adjusting the position or operating mode of the optical modules in the measurement optical path. In this case, a multi-measurement mode optical path structure can be built using fewer optical components, simplifying the optical path structure while improving the integration of the measurement system 1. In this disclosure, when measuring a cooperative target, the attenuation module 50 can be controlled to enter the measurement optical path; when measuring a non-cooperative target, the attenuation module 50 can be controlled to leave the measurement optical path.

[0131] Figure 9 This is a schematic diagram illustrating a first embodiment of the optical path structure of the ranging module 30 involved in the example of this disclosure.

[0132] For ease of description, the portion of the measurement beam L transmitted by the partial reflection unit 301 will be referred to as the target beam L1, the portion of the measurement beam L reflected by the target 2 will be referred to as the target reflected beam L11, and the portion of the measurement beam L reflected by the partial reflection unit 301 will be referred to as the reference beam L2 (see...). Figure 4 In other words, the partial reflection unit 301 can reflect a portion of the measurement beam as a reference beam L2 and transmit another portion of the measurement beam as a target beam L1. In some examples, the target beam L1 can be configured to be emitted toward the target 2. Thus, the detection of the target 2 can be achieved.

[0133] In some examples, the first detection unit 302 can obtain information about target 2 based on the interference signal between the target reflected beam L11 and the reference beam L2. In some examples, the aforementioned interference information can be the beat frequency information of the measurement beam L (including the target beam L1 and the reference beam L2). The beat frequency information is proportional to the flight time of the measurement beam L, where the flight time refers to the time it takes for the measurement beam L to travel from the measurement system 1 to the target 2.

[0134] In some examples, the beat frequency information of the target beam L1 and the reference beam L2 can be correlated with the optical path difference between the target beam L1 and the reference beam L2. In some examples, the optical path difference between the target beam L1 and the reference beam L2 can be the distance between the partial reflection unit 301 and the target 2. Thus, the distance to the target 2 can be obtained based on the beat frequency information of the target beam L1 and the reference beam L2.

[0135] In some examples, the first detection unit 302 may be coupled to the optical path between the second coupling unit 310 and the partial reflection unit 301, and the first detection unit 302 may be configured to receive the reference beam L2 and the target beam L1 reflected by the target 2 (i.e., the target reflected beam L11).

[0136] Specifically, see Figure 9 The first detection unit 302 can be configured to receive a reference beam L2 via the first coupling unit 303 and a target reflected beam L11 via the first coupling unit 303. In this case, the target beam L1 and the reference beam L2 can have a common output optical path and a common receiving optical path. Therefore, when calculating the distance to the target 2, the measurement error caused by environmental changes can be converted into a common-mode signal of both beams, and the common-mode signal can be canceled out by differential measurement, thereby improving the measurement accuracy of the target 2. In other words, the interference signal obtained based on the reference beam L2 and the target beam L1 is only related to the distance from a portion of the reflection unit 301 to the target 2. That is, the interference signal obtained based on the reference beam L2 and the target reflected beam L11 is not affected by the optical elements in the optical path structure. Here, "the target beam L1 and the reference beam L2 have a common output optical path and a common receiving optical path" means that the target beam L1 and the reference beam L2 have a common output optical path, and the target reflected beam L11 and the reference beam L2 have a common receiving optical path. Furthermore, the interference signal obtained based on the reference beam L2 and the target beam L1 actually refers to the interference signal obtained based on the reference beam L2 and the target reflected beam L11.

[0137] In this disclosure, the target beam L1 and the reference beam L2 have a common outgoing optical path, and the reference beam L2 and the target reflected beam L11 have a common receiving optical path. This arrangement can eliminate the drift information caused by temperature changes or vibrations of optical and / or electrical components in real time, thereby effectively reducing the measurement error introduced by the drift information of electrical and / or optical components.

[0138] See in some examples Figure 9 The ranging module 30 may include a first beam splitter 304. In some examples, the first beam splitter 304 may split the measurement beam L into two beams.

[0139] In some examples, the ranging module 30 can detect the target 2 based on one of the beams and correct the frequency modulation of the measuring light source 21 based on the other beam.

[0140] For ease of description, the beam used to measure target 2 will continue to be referred to as the measurement beam L, and the optical path traversed by the measurement beam L will be called the measurement optical path; the beam used to calibrate the frequency modulation of the measurement light source 21 will be called the auxiliary beam, and the optical path traversed by the auxiliary beam will be called the auxiliary optical path. In some examples, the ranging module 30 may also be referred to as including the measurement optical path and the auxiliary optical path.

[0141] See in some examples Figure 9 The ranging module 30 may include an optical fiber isolator 305 disposed between the first beam splitter 304 and the measuring light source 21. In some examples, the optical fiber isolator 305 can be used to isolate back-propagating optical signals. In this case, the optical fiber isolator 305 can isolate beams reflected by other optical elements, and also can reduce the loss of optical signals caused by back propagation.

[0142] See in some examples Figure 9 The measurement optical path may include a first polarization beam splitter unit 306 and a second polarization beam splitter unit 307. The first polarization beam splitter unit 306 can split the measurement beam L entering the measurement optical path into two sub-measurement beams, and the second polarization beam splitter unit 307 can be configured to couple the two sub-measurement beams. For ease of description, the two coupled sub-measurement beams can be referred to as the measurement beam L. In other words, the two coupled measurement beams are still referred to as the measurement beam L.

[0143] In some examples, the first polarization beam splitter 306 can be a polarization beam splitter (PBS). In this case, the first polarization beam splitter 306 can output P-polarized light (P-beam) and S-polarized light (S-beam) based on the input measurement beam L, and the polarization directions of the P-beam and the S-beam are orthogonal. In other words, the two sub-measurement beams are P-beam and S-beam with orthogonal polarization states, so that the two measurement beams can each maintain independent and stable transmission.

[0144] See in some examples Figure 9A polarization controller 308 may be provided between the first beam splitting unit 304 and the first polarization beam splitting unit 306. In some examples, the polarization controller 308 can be used to adjust the polarization state of the measurement beam L. In this case, the polarization state of the measurement beam L input to the first polarization beam splitting unit 306 can be adjusted, improving the stability of the polarization state of the measurement beam L before it enters the first polarization beam splitting unit 306, thereby improving the beam splitting efficiency and accuracy of the first polarization beam splitting unit 306.

[0145] In some examples, the second polarization beam splitter 307 can be a polarization beam splitter. In this case, the second polarization beam splitter 307 can couple the P-beam and the S-beam onto a single optical path for transmission without interference between them, which helps to simplify the optical path structure of the ranging module 30.

[0146] See in some examples Figure 9 The measurement optical path may include a modulation unit 309. In some examples, the modulation unit 309 may be disposed between the first polarization beam splitter 306 and the second polarization beam splitter 307. Thus, optical modulation of at least one sub-measurement beam is possible.

[0147] In some examples, the modulation unit 309 can be coupled via the second coupling unit 310 to the optical path containing at least one of the two sub-measurement beams (see [link]). Figure 9 ).

[0148] In some examples, the modulation unit 309 can be configured to perform anti-phase modulation on the two sub-measurement beams L. In some examples, taking a triangular linear frequency modulated continuous wave as an example, in this invention, the term "anti-phase modulation" means that the rising segment (also called the upper chirp) of the frequency function of one sub-measurement beam corresponds in time to the falling segment (also called the lower chirp) of the frequency function of another sub-measurement beam; or that the falling segment of the frequency function of one measurement beam corresponds in time to the rising segment of the frequency function of another measurement beam. In other words, the anti-phase modulated sub-measurement beam and the other measurement beam have an anti-phase relationship. In this case, ranging can be achieved using the two sub-measurement beams respectively within the duration of one rising segment (or falling segment), and the Doppler frequency shift and measurement distance can be obtained in a short time, reducing the measurement time.

[0149] See in some examples Figure 9 The measurement optical path may also include a collimation unit 311 for collimating the measurement beam L. In this case, the measurement beam L can be transformed into a parallel beam after passing through the collimation unit 311, which can improve the stability of the measurement beam L during propagation.

[0150] See in some examples Figure 9The indicator light source 22 can be coupled into the measurement optical path through a wavelength division multiplexer 312. Thus, the indicator beam and the measurement beam L can be emitted together to the target 2.

[0151] As described above, the measurement beam L propagates to the partial reflection unit 301, forming a reference beam L2 and a target beam L1. The reference beam L2 is received by the detection unit along the propagation path of the partial reflection unit 301, the first coupling unit 303, and the detection unit. Meanwhile, the target beam L1 is emitted onto the target and reflected by the target 2, forming a target reflected beam L11. The target reflected beam L11 is received by the detection unit along the propagation path of the target 2, the partial reflection unit 301, the first coupling unit 303, and the detection unit. Thus, the detection unit can measure the target 2 based on the reference beam L2 and the target reflected beam L11.

[0152] In some examples, the partial reflection unit 301 may include a quarter-wave plate. In this case, the polarization state of the measurement beam L after passing through the partial reflection unit 301 can change from linear polarization to circular polarization. Since circularly polarized light has the advantage of strong resistance to atmospheric interference, the interference signal obtained by the measurement system 1 can have a high signal-to-noise ratio, thereby improving the measurement accuracy of the measurement system 1.

[0153] In some examples, the partial reflection unit 301 may be coated with a special material behind the quarter-wave plate to achieve a semi-projection, semi-reflection function. In some examples, the partial reflection unit 301 may also have a lens with a semi-projection, semi-reflection function directly placed behind the quarter-wave plate. In some examples, the partial reflection unit 301 may be configured to receive the measurement beam L coupled via the second polarization beam splitter unit 307.

[0154] In some examples, when the first polarization beam splitter 306 is a polarization beam splitter, the measurement accuracy of the measurement system 1 can be improved by cooperating with the partial reflection unit 301 and the first polarization beam splitter 306. Specifically, after the measurement beam L passes through the first polarization beam splitter 306, it is decomposed into two orthogonally polarized beams (S-beam and P-beam). After the S-beam and P-beam pass through the partial reflection unit 301 twice, their polarization states change by 90 degrees, that is, the S-beam becomes the P-beam, and the P-beam becomes the S-beam. In this case, the polarization of the outgoing beam and the reflected beam can be separated, that is, the outgoing beam (target beam L1) and the reflected beam (reference beam L2 and target reflected beam L11) can not interfere with each other. As a result, the first detection unit 302 can obtain an interference signal with a higher signal-to-noise ratio, thereby improving the measurement accuracy of the measurement system 1.

[0155] In some examples, the first detection unit 302 may include multiple detectors. For example, see... Figure 9The detection unit may include a first detector 302a and a second detector 302b. In this case, multiple detectors can be used to receive multiple interference signals respectively, and the measurement results obtained based on multiple interference signals can improve the measurement accuracy.

[0156] In some examples, a third polarization beam splitter unit 313 may be disposed between the first detection unit 302 and the first coupling unit 303. In some examples, the third polarization beam splitter unit 313 may be used to decouple the reference beam L2 into a first reference beam and a second reference beam, and to decouple the target reflected beam L11 into a first target reflected beam and a second target reflected beam.

[0157] In some examples, the third polarization beam splitter 313 can be a polarization beam splitter. In this case, the third polarization beam splitter 313 is capable of decoupling the reference beam L2 into P-beams and S-beams, and decoupling the target reflected beam L11 into P-beams and S-beams.

[0158] In some examples, the first reference beam L2 can be a P-beam, and the second reference beam L2 can be an S-beam. Additionally, the first target reflected beam can be a P-beam, and the second target reflected beam L11 can be an S-beam.

[0159] In some examples, the first reference beam L2 can be an S-beam, and the second reference beam L2 can be a P-beam. Additionally, the first target reflected beam L11 can be an S-beam, and the second target reflected beam L11 can be a P-beam.

[0160] In some examples, the first detector 302a can receive a first reference beam L2 and a first target reflected beam L11. In some examples, the second detector 302b can receive a second reference beam L2 and a second target reflected beam L11. The interference signal received by the first detector 302a is taken as the first interference signal, and the interference signal received by the second detector 302b is taken as the second interference signal.

[0161] In some examples, the first and second interference signals may include a Doppler frequency shift and an intermediate frequency. In some examples, the Doppler frequency shift can be canceled by combining the first and second interference signals. This improves the measurement accuracy of measurement system 1.

[0162] As described above, the ranging module 30 includes an auxiliary optical path. See also: [link to example]. Figure 9 The auxiliary optical path may include a second beam splitting unit 314, a third beam splitting unit 315, and a second detection unit 316. The second beam splitting unit 314 may be configured to split the auxiliary beam into two sub-auxiliary beams, and the third beam splitting unit 315 may be configured to combine the two sub-auxiliary beams into an auxiliary beam.

[0163] In some examples, the optical paths of the two sub-auxiliary beams have a preset optical path difference. In this case, ideally, the two sub-auxiliary beams can have an optical path difference equal to the preset optical path difference. Therefore, whether the optical path difference between the two auxiliary beams is equal to the preset optical path difference can be used as a criterion to determine whether the linear frequency of the frequency-modulated continuous wave is stable. This allows control over the stability of the frequency modulation frequency of the measurement beam L, ensuring that the frequency of the measurement beam L changes uniformly and linearly with time.

[0164] In some examples, the ranging module 30 may not include an auxiliary optical path.

[0165] In some examples, a delay fiber can be placed in the optical path of either auxiliary beam. This allows the optical paths of the two auxiliary beams to have a preset optical path difference.

[0166] In some examples, the various optical components in the ranging module 30 can be connected via optical fibers. Preferably, they can be connected via polarization-maintaining fibers. In some examples, the various optical components can be polarization-maintaining optical components. In this case, the measurement beam L can maintain a stable polarization state, thereby improving the propagation stability of the measurement beam L and reducing the energy loss of the measurement beam L during propagation.

[0167] Figure 10 This is a schematic diagram illustrating a second embodiment of the optical path structure of the ranging module 30 involved in the example of this disclosure.

[0168] In some examples, the second embodiment of the optical path structure of the ranging module 30 may be substantially the same as the first embodiment of the optical path structure of the ranging module 30, but with slight differences. See the following description for details.

[0169] In some examples, the ranging module 30 may not include the first polarization beam splitter 306, the second polarization beam splitter 307, and the optical element disposed between the first polarization beam splitter 306 and the second polarization beam splitter 307.

[0170] See in some examples Figure 10In the measurement optical path, the measurement beam L1 can directly enter the first coupling unit 303. In some examples, the first coupling unit 303 can be a polarization beam splitter. After passing through the first coupling unit 303, the measurement beam L1 can be decomposed into two orthogonally polarized beams (P-beam and S-beam). When the P-beam and S-beam pass through the partial reflection unit 301 twice, the polarization states of the P-beam and S-beam will change by 90 degrees, that is, the P-beam becomes the S-beam, and the S-beam becomes the P-beam. In this case, through the cooperation of the first coupling unit 120 and the partial reflection unit 301, the polarization of the outgoing beam and the reflected beam can be separated. That is, the outgoing beam (measurement beam L1) and the reflected beam (reference beam L2 and target reflected beam L11) can not interfere with each other. As a result, the first detection unit 302 can obtain an interference signal with a higher signal-to-noise ratio, thereby improving the measurement accuracy of the measurement system 1.

[0171] In some examples, the first detection unit 302 can be a balanced detector. In some examples, the reference beam L2 and the target reflected beam L11 can be evenly split into two paths by the third polarization beam splitter 313 and received by the two channels of the first detection unit 302. Specifically, after the reference beam L2 and the target reflected beam L11 enter the third polarization beam splitter 313, they respectively enter two polarization-maintaining optical fibers, and the two polarization-maintaining optical fibers are respectively connected to the two channels of the balanced detector. In this case, the first detection unit 302 can achieve common-mode noise suppression by performing photoelectric conversion, differential operation, and amplification on the optical signal, thereby improving the signal-to-noise ratio of the interference signal, and demodulate the interference information of the reference beam L2 and the target reflected beam L11 to obtain the interference waveform, and obtain the target distance information based on the interference waveform.

[0172] While the present disclosure has been specifically described above in conjunction with the accompanying drawings and embodiments, it is to be understood that the above description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from its essential spirit and scope, and all such modifications and variations fall within the scope of the present disclosure.

Claims

1. A multi-measurement mode lidar measurement system, characterized in that, The lidar measurement system includes a generation module, a ranging module, an attenuation module, and an adjustment module. The generation module is configured to emit a measurement beam for detecting a target. The ranging module is configured to measure the target based on the measurement beam reflected by the target. The attenuation module is configured to be coupled between the ranging module and the adjustment module and to adjust the power of the measurement beam when coupled between the ranging module and the adjustment module. The adjustment module is configured to switch modes for adjusting the shape of the measurement beam based on a control signal characterizing whether the attenuation module is coupled between the ranging module and the adjustment module.

2. The multi-measurement mode lidar measurement system according to claim 1, characterized in that, The adjustment module includes a beam expansion and collimation mode and a focusing mode. The adjustment module expands and collimates the measurement beam based on the beam expansion and collimation mode, and adjusts the focusing position of the measurement beam based on the focusing mode.

3. The multi-measurement mode lidar measurement system according to claim 1 or 2, characterized in that, The adjustment module includes a first lens unit and a second lens unit. When the attenuation module is coupled between the ranging module and the adjustment module, the first lens unit and the second lens unit are fixed at a reference position for expanding and collimating the measurement beam. When the attenuation module is not coupled between the ranging module and the adjustment module, the first lens unit can move relative to the second lens unit to adjust the focusing position of the measurement beam.

4. The multi-measurement mode lidar measurement system according to claim 1, characterized in that, The generating module includes a measuring light source and an indicating light source. The measuring light source is configured to emit a measuring beam, and the indicating light source is configured to emit an indicating beam that indicates the target.

5. The multi-measurement mode lidar measurement system according to claim 4, characterized in that, It also includes a beam splitting module, a receiving module, and a processing module. When the attenuation module is coupled between the ranging module and the adjustment module, the adjustment module is located between the attenuation module and the beam splitting module. The beam splitting module is configured to receive the indicator beam reflected by the target and reflect the indicator beam reflected by the target to the receiving module. The processing module is configured to track the target based on the indicator beam received by the receiving module.

6. The multi-measurement mode lidar measurement system according to claim 4, characterized in that, It also includes a monitoring module configured to receive an indicator beam emitted by the indicator light source and control the output power of the indicator light source based on the power of the received indicator beam.

7. The multi-measurement mode lidar measurement system according to claim 1, characterized in that, It also includes a receiving module and a processing module. When the attenuation module is not coupled between the ranging module and the adjustment module, the receiving module is configured to acquire an image of the target, and the processing module is configured to plan a scanning path for scanning the target based on the image of the target.

8. The multi-measurement mode lidar measurement system according to claim 1, characterized in that, It also includes a capture module, which includes a first capture unit and a second capture unit disposed on both sides of the propagation path of the measurement beam. The first capture unit includes a first light source for emitting a first beam and a first imaging unit for receiving the first beam reflected by the target to obtain a first light spot. The second capture unit includes a second light source for emitting a second beam and a second imaging unit for receiving the second beam reflected by the target to obtain a second light spot. The capture module captures the target based on the first light spot and the second light spot.

9. The multi-measurement mode lidar measurement system according to claim 1, characterized in that, The ranging module includes a first polarization beam splitter, a modulation unit, a second polarization beam splitter, a partial reflection unit, and a first detection unit. The first polarization beam splitter is configured to split the measurement beam into two sub-measurement beams. The modulation unit is disposed between the first polarization beam splitter and the second polarization beam splitter and configured to perform anti-phase modulation on the two sub-measurement beams. The second polarization beam splitter is configured to couple the two anti-phase modulated sub-measurement beams as a measurement beam. The partial reflection unit is configured to receive the measurement beam coupled through the second polarization beam splitter, reflect a portion of the measurement beam as a reference beam, and transmit another portion of the measurement beam as a target beam. The target beam is configured to be emitted toward a target. The first detection unit is coupled to the optical path between the second coupling unit and the partial reflection unit and is configured to receive the reference beam and the target beam reflected by the target.

10. The multi-measurement mode lidar measurement system according to claim 2, characterized in that, The target includes at least one of a cooperative target that matches the beam expansion and collimation mode and a non-cooperative target that matches the focusing mode.

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