WO2020156310A1 - Scanning apparatus and scanning method therefor, and laser radar - Google Patents

Abstract

A scanning apparatus and a scanning method therefor, and a laser radar. The scanning apparatus comprises: a galvanometer (110), wherein the galvanometer (110) is provided with a moving portion (111), and the moving portion (111) is provided with a reflection face (112) suitable for reflecting an incident light beam (101), so as to form an emergent light beam (102); and the galvanometer (110) changes a propagation direction of the emergent light beam (102) by means of swinging of the moving portion (111), and at least one of the vibration frequency and amplitude of the moving portion (111) of the galvanometer (110) is variable; and a spatial light modulator (120), wherein the spatial light modulator (120) is located in a light path of at least one of the incident light beam (101) and the emergent light beam (102), and the spatial light modulator (120) is suitable for adjusting a light wave phase so as to change a propagation direction of a light beam. Insofar as a scanning frequency of the scanning apparatus is ensured, and high-frame-frequency collection is realized, the direction of a scan field of view, the size of an angle of field of view, and the resolution of the angle of field of view are adjustable, such that the field of view can be adjusted according to detection requirements, and more precise target information can be provided for a driverless field or other fields.

Description

Scanning device and scanning method, laser radar

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on January 28, 2019, the application number is 201910083057.5, and the invention title is "Scanning Device and its Scanning Method, Lidar", the entire content of which is incorporated herein by reference Applying.

Technical field

The invention relates to the field of laser detection, in particular to a scanning device, a scanning method thereof, and a laser radar.

Background technique

Lidar is a commonly used ranging sensor, which has the characteristics of long detection range, high resolution, and low environmental interference. It is widely used in intelligent robots, unmanned aerial vehicles, unmanned driving and other fields. In recent years, autonomous driving technology has developed rapidly, and lidar has become indispensable as its core sensor for distance sensing.

During the use of lidar, when a target in a certain direction is found to attract the attention of the algorithm, and further detection is required, more laser beam detection is required in this direction, that is, the number of laser lines on the target is encrypted for detection. Identify the details of the target.

However, the lidar in the prior art is often difficult to meet this demand.

Summary of the invention

The problem solved by the present invention is to provide a scanning device, a scanning method thereof, and a laser radar. Under the premise of ensuring high frame rate acquisition, the adjustment of the field of view direction, the size of the field of view, and the resolution of the field of view are realized, thereby satisfying The technical requirements for lidar to find obstacles or targets to be detected.

In order to solve the above problems, the present invention provides a scanning device including: a galvanometer, the galvanometer has a moving part, the moving part has a reflective surface suitable for reflecting the incident light beam to form an outgoing beam, and the galvanometer passes through the The swing of the moving part changes the propagation direction of the outgoing light beam, at least one of the vibration frequency and amplitude of the moving part of the galvanometer is variable; a spatial light modulator, the spatial light modulator is located at the In the optical path of at least one of the incident light beam and the outgoing light beam, the spatial light modulator is suitable for adjusting the phase of the light wave to change the propagation direction of the light beam.

Optionally, the spatial light modulator includes: at least one of a transmissive spatial light modulator or a reflective spatial light modulator.

Optionally, the spatial light modulator includes: at least one of an acousto-optic modulator, an electro-optic modulator, a magneto-optical modulator, a liquid crystal spatial light modulator, or a digital micro-reflective spatial modulator.

Optionally, the angular range for the spatial light modulator to change the beam propagation direction is 0° to 90°, the preferred angle range is 0° to 60°, and the more preferred angle range is 0° to 30°.

Optionally, it further includes: a control unit connected to the galvanometer, and the control unit is suitable for adjusting at least one of the vibration frequency and amplitude of the moving part of the galvanometer.

Optionally, the control unit is further connected to the spatial light modulator to control the adjustment of the light wave phase by the spatial modulator.

Optionally, the galvanometer includes a MEMS galvanometer.

Optionally, the galvanometer includes at least one of a one-dimensional galvanometer or a two-dimensional galvanometer.

Correspondingly, the present invention also provides a scanning method, including: providing a scanning device, which is the scanning device of the present invention; adjusting the vibration frequency and amplitude of the moving part of the galvanometer and the spatial light modulation The detector adjusts at least one of the phase magnitudes of the light waves for scanning.

Optionally, when scanning a close target, the amplitude of the galvanometer is increased.

Optionally, the scanning device sequentially receives at least two incident light beams; the at least two incident light beams sequentially form at least two outgoing light beams; when scanning a close target, the spatial light modulator is controlled so that the at least two The field of view of two outgoing beams is stitched.

Optionally, the scanning device receives at least two incident light beams; the scanning device includes at least two galvanometer mirrors and at least two spatial light modulators; the galvanometer mirror, the spatial light modulator, and the incident light beam One-to-one correspondence; when scanning a close target, the at least two spatial light modulators are controlled to splice the fields of view of the corresponding incident beams.

Optionally, when scanning a distant target, the amplitude of the galvanometer is reduced.

Optionally, the vibration frequency of the moving part of the galvanometer is increased.

Optionally, when receiving the detection signal, the spatial light modulator is adjusted according to the detection signal so that the propagation direction of the light beam faces the target to be detected.

Optionally, adjust at least one of the vibration frequency and amplitude of the moving part of the galvanometer according to the detection signal.

Optionally, when receiving the complement signal, the spatial light modulator is adjusted according to the complement signal so that the propagation direction of the light beam faces the target to be detected.

Optionally, adjust at least one of the vibration frequency and amplitude of the moving part of the galvanometer according to the complement signal.

In addition, the present invention also provides a laser radar, including: a transmitting device, the transmitting device generates an incident light beam; a scanning device, the scanning device receives the incident light beam and forms a scanning light beam according to the incident light beam, the scanning device is based The scanning device of the invention; at least part of the scanning beam is reflected by the target to be detected to form an echo beam; a receiving device, the receiving device receives the echo beam.

Optionally, it further includes: a detection device connected to the scanning device, and the detection device generates a detection signal.

Optionally, it further includes: an identification device connected to the receiving device, and the identification device determines whether the target to be detected is complete according to the echo beam received by the receiving device; The scanning device is connected, and when it is determined that the target to be detected is incomplete, the recognition device generates a complementary signal.

Compared with the prior art, the technical solution of the present invention has the following advantages:

In the technical solution of the present invention, the scanning device includes a galvanometer and a spatial light modulator whose at least one of the vibration frequency and amplitude of the moving part is variable. The adjustment of the vibration frequency and amplitude of the moving part can make the field of view and angular resolution of the scanning beam formed by the incident light beam adjustable; the setting of the spatial light modulator can make the field of view of the scanning beam The direction is adjustable. Therefore, the scanning device can realize the adjustment of the scanning field of view direction, the size of the field of view, and the field of view resolution, so that the field of view can be adjusted according to the detection requirements; and the combination of the galvanometer and the spatial light modulator can also ensure The scanning frequency of the scanning device is conducive to obtaining high frame rate collection, and provides more accurate target information for unmanned driving or other fields.

In an optional solution of the present invention, the spatial light modulator may be at least one of a transmissive spatial light modulator and a reflective spatial light modulator. The flexible selection of the light wave modulation mode of the spatial light modulator can provide a larger design space for the optical path of the scanning device, which is beneficial to the improvement of the accuracy of the optical path and the reduction of the difficulty of optical path construction.

In an alternative solution of the present invention, the spatial light modulator may be at least one of an acousto-optic modulator, an electro-optic modulator, a magneto-optical modulator, a liquid crystal spatial light modulator, or a digital micro-reflective spatial modulator. The wide selection range of the spatial light modulator can make the composed scanning device suitable for various technical requirements, thereby expanding the application range of the scanning device. In particular, the spatial light modulator may be at least one of a liquid crystal spatial light modulator and a digital micro-reflective spatial modulator. The liquid crystal spatial light modulator and the digital micro-reflective spatial modulator change the beam propagation direction at a relatively large angle, so the spatial light modulator is set to at least one of the liquid crystal spatial light modulator or the digital micro-reflective spatial modulator , The angle of change in the direction of the scanning field of view can be relatively large, and the field of view can even be directed at any angle forward, thereby further expanding the scope of application of the scanning device, which is more beneficial to the application of the scanning device in the field of unmanned driving.

In an alternative solution of the present invention, the scanning device further includes: a control unit connected to the galvanometer to adjust at least one of the frequency and amplitude of the action surface of the galvanometer; the control unit may also be connected with The spatial light modulator is connected to control the adjustment of the light wave phase by the spatial light modulator. Therefore, the control unit can coordinate the frequency and amplitude of the vibrating mirror swinging the active surface and the adjustment of the beam propagation direction by the spatial light modulator according to specific requirements, so that the formed scanning beam has better or even the most The best field of view direction, field of view angle size and field of view resolution provide more accurate information for the discovery and complete detection of obstacles or targets to be detected.

Description of the drawings

1 is a schematic diagram of the optical path structure of an embodiment of the scanning device of the present invention;

2 is a schematic diagram of the optical path when the phase delay caused by the spatial light modulator in FIG. 1 is equivalent to the phase delay caused by the glass plate;

3 is a schematic diagram of the optical path when the phase delay caused by the spatial light modulator in FIG. 1 is equivalent to the triangular prism whose thickness gradually increases along the +x direction;

4 is a schematic diagram of the optical path when the phase delay caused by the spatial light modulator in FIG. 1 is equivalent to the triangular prism whose thickness gradually increases along the -x direction;

FIG. 5 is a schematic flowchart of an embodiment of the scanning method of the present invention.

detailed description

It can be known from the background technology that the laser radar scanning device in the prior art has the problem that the field of view angle direction, size, and angular resolution cannot meet the detection requirements.

In the prior art, the solid-state laser radar implementation method is mainly a MEMS galvanometer solution. After the machine is installed, the MEMS galvanometer solution has a fixed field of view area and can only detect targets within the maximum field of view. It cannot perform encrypted detection of any target in the measurement area to identify more specific details.

The realization method of solid-state laser radar is mainly MEMS galvanometer scheme. After the machine is installed, the MEMS galvanometer solution has a fixed field of view and can only be detected in a certain area. By changing the amplitude of the galvanometer, the size of the field of view can be changed to achieve encrypted detection, but it can only observe a fixed one. It is impossible to observe any direction within the field of view for encrypted detection, let alone detect targets outside the maximum field of view. If only the spatial light modulator is used, the spatial light modulator is slow, which is not conducive to obtaining high frame rate acquisition.

To solve the technical problem, the present invention provides a scanning device, including: a galvanometer with a moving part, at least one of the vibration frequency and amplitude of the moving part of the galvanometer is variable; A spatial light modulator in the optical path of at least one of the light beam and the outgoing light beam, and the spatial light modulator is suitable for adjusting the phase of the light wave to change the propagation direction of the light beam. The combination of a galvanometer and a spatial light modulator in which at least one of the vibration frequency and amplitude of the moving part is variable can make the scanning field of view, the size of the field of view and the field of view resolution of the scanning device Adjustable, so that the field of view can be adjusted according to the detection requirements; and the combination of the galvanometer and the spatial light modulator can also ensure the scanning frequency of the scanning device, which is conducive to obtaining high frame rate acquisition, which is suitable for unmanned driving or other The field provides more accurate target information.

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Referring to FIG. 1, a schematic diagram of the optical path structure of an embodiment of the scanning device of the present invention is shown.

The scanning device includes: a galvanometer 110, the galvanometer 110 has a moving part 111, the moving part 111 has a reflecting surface 112 suitable for reflecting the incident light beam 101 to form an outgoing light beam 102, and the galvanometer 110 passes through the The oscillation of the moving part 111 changes the propagation direction of the outgoing light beam 102, at least one of the vibration frequency and the amplitude of the moving part 111 of the galvanometer 110 is variable; the spatial light modulator 120, the spatial light The modulator 120 is located in the optical path of at least one of the incident light beam 101 and the outgoing light beam 102, and the spatial light modulator 120 is suitable for adjusting the phase of the light wave to change the light beam propagation direction.

The adjustment of the vibration frequency and amplitude of the moving part 111 can make the field angle size and field angle resolution of the scanning beam 103 formed by the incident beam 101 adjustable; the setting of the spatial light modulator 120 can make The direction of the field of view of the scanning beam 103 is adjustable. Therefore, the scanning device can realize the adjustment of the scanning field of view direction, the size of the field of view, and the field of view resolution, so that the field of view can be adjusted according to the detection requirements; and the combination of the galvanometer 110 and the spatial light modulator 120 also provides The scanning frequency of the scanning device can be guaranteed, which is conducive to obtaining high frame rate collection, and provides more accurate target information for unmanned driving or other fields.

The technical solution of the present invention will be described in detail below in conjunction with the drawings.

The galvanometer 110 includes a moving part 111 having a reflective surface 112, and the reflective surface 112 can reflect the received light. Specifically, the scanning device receives the collimated incident light beam 101, the incident light beam 101 is projected onto the reflecting surface 112, and is reflected by the reflecting surface 112 to form the outgoing light beam 102.

The galvanometer 110 also includes a rotating shaft (not shown in the figure), and the moving part 111 can swing around the rotating shaft; at least part of the surface of the moving part 111 is the reflecting surface 112, which follows the movement With the swing of the moving part 111, the reflecting surface 112 also swings accordingly; when the propagation direction of the incident light beam 101 remains unchanged, the propagation direction of the outgoing light beam 102 will also change with the swing of the moving part 111. The change occurs so that the formed scanning beam 103 realizes scanning.

It should be noted that the galvanometer 110 includes at least one of a one-dimensional galvanometer and a two-dimensional galvanometer. The rotating shaft is not shown in FIG. 1. In an embodiment of the present invention, the galvanometer is a two-dimensional galvanometer, which can swing in two mutually perpendicular dimensions, so that the scanning beam scans a three-dimensional space. In other embodiments of the present invention, the galvanometer may also be a one-dimensional galvanometer, the axis of the rotating shaft of the galvanometer is arranged perpendicular to the paper surface, and the moving part swings around the rotating shaft. However, these setting modes are only some examples, and the present invention does not limit the position and setting mode of the rotating shaft.

The amplitude of the moving part 111, that is, the amplitude of the swing of the moving part 111, is related to the field angle of the scanning beam 103: the larger the amplitude of the moving part 111, the scanning beam 103 The larger the angle of view of the moving part 111 is; the smaller the amplitude of the moving part 111 is, the smaller the angle of view of the scanning beam 103 is.

Moreover, when the incident light beam 101 is unchanged (that is, when the incident light beam 101 is pulsed light, the pulse frequency of the incident light beam 101 does not change), the size of the field angle of the scanning beam 103 will also affect the scanning beam The angular resolution of 103: the larger the field of view of the scanning beam 103, the larger the angle between adjacent scanning beams 103, the lower the line beam density, and the lower the angular resolution; the viewing angle of the scanning beam 103 The smaller the field angle, the smaller the angle between adjacent scanning beams 103, the higher the line beam density and the higher the angular resolution.

On the other hand, when the size of the field of view does not change or the field of view changes within a certain range, the vibration frequency of the moving part 111, that is, the frequency at which the moving part 111 oscillates, the level of the vibration frequency and the scanning The angular resolution of the light beam 103 is related: the higher the vibration frequency of the moving part 111, the less the scanning beam, the lower the angular resolution of the scanning beam 103; the lower the vibration frequency of the moving part 111, the scanning the beam The more, the higher the angular resolution of the scanning beam 103 is.

At least one of the vibration frequency and amplitude of the moving part 111 is variable. Therefore, when the propagation direction of the incident light 101 remains unchanged, the propagation direction of the reflected light beam 102 formed by the reflection of the reflecting surface 112 and At least one of the frequencies at which the propagation direction changes is variable, so that the field angle and the angular resolution of the scanning beam 103 can be adjusted.

It should be noted that, in this embodiment, the swing of the moving part 111 is driven by a magnetic field, so the purpose of controlling the vibration frequency and amplitude of the moving part 111 can be achieved by changing the magnitude and frequency of the magnetic field.

In this embodiment, the vibration frequency and amplitude of the moving part 111 are adjustable. In other embodiments of the present invention, the galvanometer 110 may also be set to have an adjustable vibration frequency, or set to have an adjustable amplitude.

In this embodiment, the galvanometer 110 includes a MEMS galvanometer. In the scanning device, the method of setting the galvanometer 110 as a MEMS galvanometer can effectively improve the integration of the scanning device and increase the scanning frequency of the scanning device.

With continued reference to FIG. 1, the scanning device further includes a spatial light modulator 120. The spatial light modulator 120 is a device that modulates the spatial distribution of light waves, and has the function of spatially modulating light beams in real time, so as to adjust the phase of light waves to achieve the effect of changing the direction of light beam propagation.

With reference to FIGS. 2 to 4, the schematic diagrams of equivalent light paths in the dashed frame 100 in the scanning device shown in FIG. 1 under different modulation conditions are respectively shown.

2 shows a schematic diagram of the optical path when the phase delay caused by the spatial light modulator 120 is equivalent to the phase delay caused by the glass plate.

When the outgoing beam 102 formed by the galvanometer lens 110 has a field of view of (-α, +α) in the xy plane (as shown in FIG. 2), the phase delay caused by the spatial light modulator 120 and the glass The phase delay caused by the plate is equivalent, so the setting of the spatial light modulator 120 will not cause the change of the beam propagation direction, that is, the light beam emitted from the spatial light modulator 120 also has a (-α, +α) visual field. Therefore, the field angle of the formed scanning beam 103 is still (-α, +α).

FIG. 3 shows a schematic diagram of the optical path when the phase delay caused by the spatial light modulator 120 is equivalent to a triangular prism whose thickness gradually increases along the +x direction.

When the outgoing beam 102 formed by the galvanometer 110 has a field of view angle of (-α, +α) in the xy plane, the phase delay caused by the spatial light modulator 120 and the thickness along the +x direction gradually increase The three prisms are equivalent, so the setting of the spatial light modulator 120 will make the beam in the xy plane rotate in the -z direction (that is, perpendicular to the paper surface) as the axis rotation angle θ (even if the chief ray is rotated around the -z direction as the axis θ, where the chief ray refers to the ray passing through the center of the pupil of the optical system), so the light beam emitted from the spatial light modulator 120 has a field of view angle of (-α-θ, α-θ), and the resulting scan The field angle of the beam is (-α-θ, α-θ).

FIG. 4 shows a schematic diagram of the optical path when the phase delay caused by the spatial light modulator 120 is equivalent to a triangular prism whose thickness gradually increases along the −x direction.

Similarly, when the outgoing beam 102 formed by the galvanometer 110 has a field of view of (-α, +α) in the xy plane, the phase delay caused by the spatial light modulator 120 and the thickness along the -x direction The gradually increasing triangular prism is equivalent, so the setting of the spatial light modulator 120 will make the beam in the xy plane take the +z direction (that is perpendicular to the paper surface outward) as the axis, and rotate the angle θ (even if the chief ray is in the +z direction Is the axis rotation angle θ, where the chief ray refers to the ray passing through the center of the pupil of the optical system), so the light beam exiting from the spatial light modulator 120 has a (-α+θ, α+θ) field of view, thus The field angle of the formed scanning beam is (-α+θ, α+θ).

It can be seen that by adjusting the phase delay of the spatial light modulator 120, the propagation direction of the beam emitted from the spatial light modulator 120 (that is, the propagation direction of the chief ray) can be changed, so that the galvanometer 110 is not changed. Under the premise of the swing angle of the moving part 111, the purpose of changing the direction of the field angle of the formed scanning beam is achieved.

Continuing to refer to FIG. 1, since the setting of the spatial light modulator 120 can change the direction of the field of view of the scanning device, combined with the variable vibration frequency and amplitude of the galvanometer 110, if the amplitude is reduced, the incident When the light beam 101 remains unchanged, the angle between adjacent scanning light beams 103 can be reduced, so as to achieve the purpose of laser beam in the chief ray direction, improve angular resolution, and realize encrypted detection. It can be seen that the combination of the galvanometer 110 with variable vibration frequency and amplitude and the spatial light detector 120 can adjust the direction of the field of view, the size of the field of view, and the resolution of the field of view according to detection requirements. The scanning frequency of the scanning device can be guaranteed, which is conducive to obtaining high frame rate collection, and provides more accurate target information for unmanned driving or other fields.

The spatial light modulator 120 includes at least one of a transmissive spatial light modulator or a reflective spatial light modulator. In this embodiment, the spatial light modulator 120 is a transmissive spatial light modulator, that is, the outgoing beam 102 projects the spatial light modulator 120 to form the scanning beam 103. In other embodiments of the present invention, the spatial light modulator may also be configured as a reflective spatial light modulator. The flexible selection of the light wave modulation mode of the spatial light modulator can provide a larger design space for the optical path of the scanning device, which is beneficial to the improvement of the accuracy of the optical path and the reduction of the difficulty of optical path construction.

The spatial light modulator 120 includes at least one of an acousto-optic modulator, an electro-optic modulator, a magneto-optic modulator, a liquid crystal spatial light modulator, or a digital micro-reflective spatial modulator. The wide selection range of the spatial light modulator can make the formed scanning device suitable for a variety of technical requirements, thereby expanding the scope of application of the scanning device.

In this embodiment, the spatial light modulator 120 is a liquid crystal spatial light modulator. The liquid crystal spatial light modulator and the digital micro-reflective spatial modulator change the beam propagation direction at a relatively large angle, so the spatial light modulator 120 is set as at least one of the liquid crystal spatial light modulator or the digital micro-reflective spatial modulator In this way, the angle of change in the direction of the scanning field of view can be relatively large, and the field of view can even be directed at any angle forward, which can further expand the scope of application of the scanning device and is more beneficial to the application of the scanning device in the field of unmanned driving.

In this embodiment, the angular range for the spatial light modulator 120 to change the beam propagation direction is 0° to 90°, the preferred angle range is 0° to 60°, and the more preferred angle range is 0° to 30°. Setting the angle at which the spatial light modulator 120 changes the beam propagation direction within a reasonable range can select a suitable spatial light modulator according to actual needs, so as to achieve a balance between performance and cost.

It should be noted that, as shown in FIG. 1, in this embodiment, the spatial light modulator 120 is disposed in the optical path of the exit beam 102, that is, the spatial light modulator 120 receives the exit beam 102, and The light wave phase of the outgoing beam 102 is adjusted to achieve the purpose of changing the propagation direction of the beam, and then used to form the scanning beam 103.

In other embodiments of the present invention, the spatial light modulator may also be located in the optical path of the incident light beam, that is, the spatial light modulator receives the incident light beam and adjusts the light wave phase of the incident light beam to change the light beam propagation direction; The light beam whose light wave phase is adjusted by the spatial light modulator is projected onto the reflection surface, and is reflected by the reflection surface to form a scanning beam.

It should also be noted that the scanning device further includes a control unit (not shown in the figure) electrically connected to the galvanometer 110, and the control unit is suitable for adjusting the moving part 111 of the galvanometer 110. At least one of the vibration frequency and amplitude.

In this embodiment, the control unit provides a driving voltage to the galvanometer 110 to make the moving part 111 swing. The control unit can change at least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 by changing at least one of the magnitude and frequency of the driving voltage. In other embodiments of the present invention, the control unit may also adjust the swing of the moving part of the galvanometer in other ways.

In addition, the control unit is also connected to the spatial light modulator 120 to control the adjustment of the light wave phase by the spatial modulator. The control unit can coordinate the frequency and amplitude of the galvanometer 110 swinging the active surface and the adjustment of the beam propagation direction by the spatial light modulator 120 according to specific requirements, so that the formed scanning beam 103 has a better Even the best field of view direction, field of view size and field of view resolution provide more accurate information for the discovery and complete detection of obstacles or targets to be detected.

Correspondingly, the present invention also provides a scanning method.

Specifically referring to FIG. 5, a schematic flowchart of an embodiment of the scanning method of the present invention is shown.

The scanning method includes: performing step S510, providing a scanning device, which is the scanning device of the present invention; performing step S520, adjusting the vibration frequency and amplitude of the moving part of the galvanometer and adjusting the spatial light modulator At least one of the light wave phase size to scan.

By adjusting at least one of the vibration frequency and amplitude of the moving part of the galvanometer and the spatial light modulator adjusting the light wave phase size, the field of view direction and field angle of the scanning beam formed by the scanning device can be adjusted And the field of view resolution, so that the field of view direction, field of view size and field of view resolution of the scanning beam are closer to the specific detection requirements, and the scanning direction selection and local encryption scanning can be realized under the premise of ensuring the scanning frequency. Or complete specific functions such as the target to be detected, which can provide more accurate target information for the subsequent algorithm, which is conducive to the algorithm to identify the target, and is conducive to improving the scanning precision and accuracy.

With reference to FIG. 1, step S510 is performed to provide a scanning device (not labeled in the figure). Since the scanning device is the scanning device of the present invention, the specific technical solution of the scanning device can refer to the foregoing embodiment, which will not be repeated in the present invention.

As shown in FIG. 1, the scanning device includes a galvanometer 110 and a spatial light modulator 120. At least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 is variable. The spatial light modulator The device 120 can adjust the phase of the light wave to change the light beam propagation direction.

It should be noted that in this embodiment, the scanning device is applied to lidar. Specifically, the lidar includes: a transmitting device 130 that generates an incident light beam 101; the scanning device receives the incident light beam 101 and forms a scanning light beam 103 according to the incident light beam 101; at least part of the scanning light beam 103 An echo beam (not shown in the figure) is reflected by the target 160 to be detected; a receiving device 150, which receives the echo beam.

With reference to FIG. 5, step S520 is performed to adjust at least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 and the spatial light modulator 120 to adjust the light wave phase size for scanning.

Adjusting the spatial light modulator 120 to change the light wave phase can change the field of view direction of the scanning beam 103; adjusting the amplitude of the moving part 111 of the galvanometer 110 can change the field of view angle of the scanning beam 103; Adjusting the vibration frequency of the moving part 111 of the galvanometer 110 can change the angular resolution of the scanning beam 103; therefore, according to the detection requirements, set the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 And the spatial light modulator 120 adjusts at least one of the light wave phases to be closer to the specific detection requirements, so as to achieve specific scanning direction selection, local encryption scanning, or completion of the target 160 to be detected under the premise of ensuring the scanning frequency. Features.

When scanning a nearby target, the amplitude of the galvanometer 110 is increased. When scanning a close target, the required field of view is relatively large. Therefore, increasing the amplitude of the galvanometer 110 can expand the field of view of the scanning beam 103 to meet the requirements of scanning close targets.

In other embodiments of the present invention, the scanning device receives at least two incident light beams, and forms at least two scanning light beams emitted from the scanning device according to the at least two incident light beams, wherein the at least two incident light beams It can be distinguished in space or time. For example, the scanning device sequentially receives the at least two incident light beams, or the scanning device receives at least two incident light beams with different propagation directions; The at least two incident light beams have a one-to-one correspondence; the spatial light modulator is controlled to make the field of view of the at least two outgoing light beams face different directions, so as to realize multi-directional scanning simply and conveniently.

In some embodiments of the present invention, after receiving at least two incident light beams, the spatial light modulator may be controlled so that the field of view of the at least two outgoing light beams can be spliced, thereby further expanding the scanning device formed The field of view of the scanning beam.

Especially when scanning a close target, by controlling the spatial light modulator so that the fields of view of the at least two outgoing beams are adjacent to each other or partially overlapped with each other to achieve the effect of field of view splicing, which can be achieved without changing the hardware equipment Under the premise, the realization of the expansion of the field of view is more conducive to the application of unmanned driving and other fields.

It should be noted that in some embodiments of the present invention, the scanning device has multiple optical paths, and each optical path is provided with a galvanometer and a spatial light modulator. Specifically, the scanning device receives at least two incident light beams, and forms at least two corresponding scanning light beams emitted from the scanning device according to the at least two incident light beams; the scanning device includes at least two galvanometers And at least two spatial light modulators; the galvanometer mirror, the spatial light modulator and the incident light beam correspond one to one.

Among them, in some embodiments, by separately controlling the spatial light modulator in each optical path to make the field of view of the outgoing beams corresponding to the at least two incident beams face different directions, different directions can be realized simply and conveniently. While scanning. In some embodiments, it is also possible to control the spatial light modulator in each optical path separately so that the fields of view of the at least two scanning beams formed are adjacent to each other or partially overlapped, so as to achieve the effect of field splicing.

When scanning a distant target, the amplitude of the galvanometer 110 is reduced. When scanning a distant target, the requirement on the size of the field of view is relatively low, and the requirement on the detection resolution is relatively high. Therefore, when scanning the distant target, the amplitude of the galvanometer 110 is reduced to improve the beam line near the chief ray. Density to obtain higher angular resolution, thereby improving the scanning effect of distant targets.

In addition, when scanning a distant target, in addition to reducing the amplitude of the galvanometer 110, the vibration frequency of the moving part 111 of the galvanometer 110 can also be reduced, combined with an increase in the pulse frequency of the incident beam 101. Further increase the line density of the scanning beam 103 to obtain higher angular resolution, which is more conducive to improving the accuracy of long-distance target detection.

It should be noted that, in this embodiment, the lidar further includes: a processing device (not shown in the figure), the processing device obtains scan data based on the echo beam, and obtains a point cloud image based on the scan data , Wherein the scanning data includes at least an azimuth angle and distance of at least one incident point of the scanning beam (that is, the position where the scanning beam is reflected to form an echo beam).

In addition, in this embodiment, a distance threshold is preset in the processing device, and the processing device compares the distance of at least one of the scanning beam incident points with the distance threshold and determines the distance of the scanned target according to the comparison result : When the distance of the at least one scanning beam incident point is greater than the distance threshold, the processing device determines that the scanning target is a distant target; when the at least one scanning beam incident point is less than the distance When the distance threshold is used, the processing device determines that the scan target is a close target.

The processing device also generates a far scan signal and a near scan signal based on the result of determining the distance of the scanned target: when determining that the scan target is a far target, the processing device generates a far scan signal; When the scanning target is a nearby target, the processing device generates a nearby scanning signal.

In this embodiment, the scanning device includes a control unit (not shown in the figure) connected to both the galvanometer 110 and the spatial light modulator 120; the control unit receives the remote scanning signal or the According to the near scan signal, the galvanometer 110 and the spatial light modulator 120 are adjusted according to the received far scan signal or near scan signal.

In addition, in this embodiment, the processing device judges the distance of the scanned target based on the feedback of the echo beam. However, in other embodiments of the present invention, the judgment can be made by manual input selection, which is not limited in the present invention.

In addition, in this embodiment, the preset distance threshold in the processing device may be a single value, or may be multiple different values set according to different scenarios. For example, when the lidar is applied in the field of unmanned driving, the processing device is preset with scene modes corresponding to different road conditions, such as high-speed mode, crowded mode, etc., and different scene modes can be set. The distance threshold, for example, the distance threshold is relatively large in the high-speed mode, and the distance threshold is relatively small in the crowded mode. However, the above setting method is only an example, and the scope of the present invention cannot be limited by this.

In this embodiment, the scanning device also receives a detection signal, which is suitable for driving the scanning device to detect the target 160 to be detected. When receiving the detection signal, the spatial light modulator 120 is adjusted according to the detection signal so that the beam propagation direction is toward the target 160 to be detected.

Specifically, the detection signal includes position information of the target 160 to be detected, and the position information includes at least the azimuth angle of the position of the target 160 to be detected; adjust the spatial light modulator according to the detection signal 120. The field of view is shifted to the target 160 to be detected, even if the direction of the field of view is toward the direction of the target 160 to be detected, the chief ray is caused to propagate in the direction of the target 160 to be detected, so as to be able to target the target 160 to be detected. The target 160 is scanned to obtain more accurate scan data of the target 160 to be detected.

While adjusting the spatial light modulator 120, at least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 can be further adjusted according to the detection signal to make the scanning beam 103 visible The field angle and the angular resolution are suitable for the scanning of the target 160 to be detected. For example, the amplitude of the galvanometer 110 can be appropriately reduced to reduce the angle of view, so as to achieve the effect of local encryption; The amplitude of the galvanometer 110 and the pulse frequency and vibration frequency of the incident beam 101 are simultaneously increased to ensure that the target 160 to be detected is within the field of view of the scanning beam 103 while obtaining a higher line beam density. Realize the balance of field of view and angular resolution.

It should be noted that, in this embodiment, the lidar further includes: a detection device (not shown in the figure), the detection device generates a detection signal according to the scanning data obtained by the processing device; the scanning device and The detection device is connected, and the detection signal is obtained from the detection device. Specifically, the scanning device has a control unit connected to both the galvanometer 110 and the spatial light modulator 120, the control unit is connected to the detection device, and receives the detection signal from the detection device, The adjustment of the galvanometer 110 and the spatial light modulator 120 is realized according to the detection signal.

It should also be noted that the above-mentioned method of generating a detection signal by the detection device according to the scan data is only an example. In other embodiments of the present invention, the detection device may also receive instructions manually input by the user, and generate detection signals according to the received instructions. Signal to realize the detection of the target 160 to be detected. The present invention does not limit the manner of generating the detection signal.

In addition, in this embodiment, the scanning device also receives a supplementary signal, which is suitable for starting the scanning device's targeted scanning of the discovered target 160 to be detected. Specifically, after receiving the complement signal, the spatial light modulator 120 is adjusted according to the complement signal so that the beam propagation direction is toward the target 160 to be detected.

In addition, the target 160 to be detected within the range of the field of view has been found, but the target 160 to be detected is judged to be incomplete according to the feedback scan data, and the target 160 to be detected cannot be identified. At this time, the scanning device receives the complement signal to obtain complete scan data of the target 160 to be detected.

Specifically, the complement signal includes position information of the target 160 to be detected, and the position information includes at least the azimuth angle of the position of the target 160 to be detected; and the spatial light is adjusted according to the complement signal. The modulator 120 transfers the field of view to the target 160 to be detected, so that the target 160 to be detected is located in the middle of the field of view as much as possible, so as to obtain complete scan data of the target 160 to be detected.

At the same time, it is also possible to further adjust at least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 according to the complement signal, so as to make the field of view and angular resolution of the scanning beam 103 The rate is suitable for the scanning of the target 160 to be detected.

It should be noted that, in this embodiment, the lidar further includes: an identification device (not shown in the figure), which identifies the target 160 to be detected according to the scan data obtained by the processing device , And determine whether the target 160 to be detected is complete; when it is determined that the target 160 to be detected is incomplete, the identification device generates a complement signal. The scanning device is connected to the identification device, and the complement signal is obtained from the identification device. Specifically, the scanning device has a control unit connected to both the galvanometer 110 and the spatial light modulator 120, the control unit is connected to the identification device, and the complement signal is received from the identification device , And adjust the galvanometer 110 and the spatial light modulator 120 according to the complement signal.

It should also be noted that the method of generating the complementary signal based on the scan data by the above identification device is only an example. In other embodiments of the present invention, the identification device may also receive an instruction manually input by the user, and generate a supplementary signal according to the received instruction to realize the detection of the target 160 to be detected. The present invention does not limit the generation method of the complement signal.

In addition, in this embodiment, the control unit in the scanning device and the processing device, detection device, and identification device in the lidar can all pass through one or more Field Programmable Gate Arrays (FPGA). to fulfill. The present invention does not limit this, and it can also be realized by other hardware that can realize the same function.

Correspondingly, the present invention also provides a laser radar.

As shown in FIG. 1, a schematic diagram of the optical path structure of an embodiment of the laser radar of the present invention is shown.

The lidar includes: a transmitting device 130, which generates an incident light beam 101; a scanning device (not shown in the figure), which receives the incident light beam 101 and forms a scanning light beam 103 according to the incident light beam 101. The scanning device is the scanning device of the present invention; at least part of the scanning beam 103 is reflected by the target 160 to be detected to form an echo beam (not shown in the figure); a receiving device 150, which receives the echo beam .

Since the scanning device is the scanning device of the present invention, it includes a galvanometer 110 and a spatial light modulator 120 in which at least one of the vibration frequency and amplitude of the moving part 111 is variable. The adjustment of the vibration frequency and amplitude of the moving part 111 can make the field of view and the angular resolution of the scanning beam 103 formed by the incident beam 101 adjustable; the setting of the spatial light modulator 120 can make the The direction of the field of view of the scanning beam 103 is adjustable. Therefore, the scanning device can realize the adjustment of the scanning field of view direction, the size of the field of view, and the field of view resolution, so that the field of view can be adjusted according to the detection requirements; and the combination of the galvanometer 110 and the spatial light modulator 120 also provides The scanning frequency of the scanning device can be guaranteed, which is conducive to obtaining high frame rate collection, and provides more accurate target information for unmanned driving or other fields.

In this embodiment, the lidar is a lidar with a common path for transmitting and receiving. The light generated by the emitting device 130 is collimated to form a collimated beam, and the collimated beam is formed by a beam splitting device (not shown in the figure) to form the incident beam 101; including the galvanometer 110 and the spatial light The scanning device (not shown in the figure) of the modulator 120 receives the incident light beam 101, and the incident light beam 101 is reflected by the reflecting surface 112 of the galvanometer 110 and the light wave phase is adjusted by the spatial light modulator 120 to form a scan Light beam 103; at least part of the scanning beam 103 is projected onto the target 160 to be detected and scattered, and the backscattered light therein forms an echo beam; the echo beam is collected by the scanning device, that is, through the The spatial light modulator 120 transmits, and then is reflected by the reflection surface 112 of the galvanometer 110 and reflected by the beam splitting device to project to the converging device 140; the converging device 140 projects the received echo beam to the The receiving device 150 at the focal point; the receiving device 150 collects the optical signal of the echo beam and performs photoelectric conversion to form a corresponding electrical signal.

It should be noted that, in this embodiment, the lidar further includes: a processing device (not shown in the figure), the processing device is connected to the receiving device 150, and the formed electricity is obtained from the receiving device 150 Signal, and obtain scanning data according to the electrical signal, and further obtain a point cloud image according to the scanning data, wherein the scanning data includes at least one incident point of the scanning beam (that is, the scanning beam is reflected to form an echo beam Position) azimuth and distance.

In this embodiment, the lidar further includes: a detection device (not shown in the figure), the detection device generates a detection signal according to the scanning data obtained by the processing device; the scanning device is connected to the detection device , Obtaining the detection signal from the detection device. Specifically, the scanning device has a control unit connected to both the galvanometer 110 and the spatial light modulator 120, the control unit is connected to the detection device, and receives the detection signal from the detection device, The adjustment of the galvanometer 110 and the spatial light modulator 120 is realized according to the detection signal.

The detection signal is suitable for driving the scanning device to detect the target 160 to be detected. When receiving the detection signal, the scanning device adjusts the spatial light modulator 120 according to the detection signal so that the beam propagation direction is toward the target 160 to be detected.

Specifically, the detection signal includes position information of the target 160 to be detected, and the position information includes at least the azimuth angle of the position of the target 160 to be detected; according to the detection signal, the control unit of the scanning device Adjust the spatial light modulator 120 to shift the field of view to the target 160 to be detected, even if the direction of the field of view faces the direction of the target 160 to be detected, so that the chief ray propagates in the direction of the target 160 to be detected, In this way, the target 160 to be detected can be scanned to obtain more accurate scan data of the target 160 to be detected.

While adjusting the spatial light modulator 120, the control unit of the scanning device may further adjust at least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 according to the detection signal, so that The size of the field of view and the angular resolution of the scanning beam 103 are suitable for the scanning of the target 160 to be detected. For example, the control unit can reduce the field of view by appropriately reducing the amplitude of the galvanometer 110 to achieve The effect of local encryption; the control unit can also appropriately increase the amplitude of the galvanometer 110, and at the same time increase the pulse frequency and vibration frequency of the incident beam 101, so as to ensure that the complete target 160 to be detected is located in the scanning beam In the 103 field of view, a higher wire density is obtained, achieving the balance of field of view and angular resolution.

It should be noted that the above-mentioned method of the detection device generating detection signals based on scan data is only an example. In other embodiments of the present invention, the detection device may also receive instructions manually input by the user, and generate detection signals according to the received instructions. In order to realize the detection of the target 160 to be detected. The present invention does not limit the manner of generating the detection signal.

In addition, in this embodiment, the lidar further includes: a recognition device (not shown in the figure), which recognizes the target 160 to be detected according to the scan data obtained by the processing device, and determines Whether the target 160 to be detected is complete; when it is determined that the target 160 to be detected is incomplete, the identification device generates a complement signal. The scanning device is connected to the identification device, and the complement signal is obtained from the identification device. Specifically, the scanning device has a control unit connected to both the galvanometer 110 and the spatial light modulator 120, the control unit is connected to the identification device, and the complement signal is received from the identification device , And adjust the galvanometer 110 and the spatial light modulator 120 according to the complement signal.

The complementary signal is suitable for initiating the targeted scanning of the discovered target 160 by the scanning device. Specifically, upon receiving the complement signal, the scanning device adjusts the spatial light modulator 120 according to the complement signal so that the beam propagation direction is toward the target 160 to be detected.

In addition, the target 160 to be detected within the range of the field of view has been found, but the recognition device determines that the target 160 to be detected is incomplete according to the scan data, and the target 160 to be detected cannot be recognized. At this time, the scanning device receives the complement signal generated by the identification device to obtain the complete scan data of the target 160 to be detected.

Specifically, the complement signal includes position information of the target 160 to be detected, and the position information includes at least the azimuth angle of the position of the target 160 to be detected; according to the complement signal, the scanning device The control unit adjusts the spatial light modulator 120 to transfer the field of view to the target 160 to be detected, so that the target 160 to be detected is located in the middle of the field of view as much as possible, so as to obtain a complete scan of the target 160 to be detected data.

At the same time, the control unit of the scanning device may further adjust at least one of the vibration frequency and amplitude of the moving part 111 of the galvanometer 110 according to the complement signal, so that the scanning beam 103 is The size of the field of view and the angular resolution are suitable for scanning the target 160 to be detected.

It should be noted that the above-mentioned method of generating a complement signal based on scan data by the identification device is only an example. In other embodiments of the present invention, the identification device may also receive an instruction manually input by the user, and generate a supplementary signal according to the received instruction to realize the detection of the target 160 to be detected. The present invention does not limit the generation method of the complement signal.

It should be noted that, in this embodiment, the transmitting device 130 may include a laser; the light splitting device may include a half mirror; the converging device 140 may include a converging lens; and the receiving device may include a photodetector . However, the above-mentioned setting method is only an example, and the present invention does not limit the specific setting methods of the transmitting device, the spectroscopic device, the converging device, and the receiving device.

It should also be noted that the lidar may be a lidar that performs detection based on time of flight, that is, after collecting the optical signal of the echo beam, the time delay between the echo beam and the incident beam can be calculated to be detected. The distance of the target 160, thereby realizing the positioning of the target 160 to be detected. In other embodiments of the present invention, the lidar may also be a lidar based on desired detection; that is, after collecting the optical signal of the echo beam, obtain the target 160 to be detected according to the coherent information of the echo beam and the incident beam. distance. The present invention does not limit the detection mode of the lidar.

In addition, in this embodiment, the control unit in the scanning device and the processing device, detection device, and identification device in the lidar can all pass through one or more Field Programmable Gate Arrays (FPGA). to fulfill. The present invention does not limit this, and it can also be realized by other hardware that can realize the same function.

Although the present invention is disclosed as above, the present invention is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims (21)

1. A scanning device, characterized by comprising:

   A galvanometer, the galvanometer has a moving part, the moving part has a reflecting surface suitable for reflecting the incident light beam to form an outgoing beam, and the galvanometer changes the propagation direction of the outgoing beam by swinging the movable part, At least one of the vibration frequency and amplitude of the moving part of the galvanometer is variable;

   A spatial light modulator, where the spatial light modulator is located in an optical path of at least one of the incident light beam and the outgoing light beam, and the spatial light modulator is suitable for adjusting the phase of the light wave to change the light beam propagation direction.
2. The scanning device according to claim 1, wherein the spatial light modulator comprises at least one of a transmissive spatial light modulator or a reflective spatial light modulator.
3. The scanning device according to claim 1 or 2, wherein the spatial light modulator comprises: an acousto-optic modulator, an electro-optic modulator, a magneto-optic modulator, a liquid crystal spatial light modulator, or a digital micro-reflective spatial modulator At least one of them.
4. The scanning device according to claim 1, wherein the angle range of the spatial light modulator to change the beam propagation direction is 0° to 90°.
5. The scanning device according to claim 1, further comprising: a control unit connected to the galvanometer, the control unit being suitable for adjusting the vibration frequency of the moving part of the galvanometer And at least one of amplitude.
6. 8. The scanning device according to claim 5, wherein the control unit is further connected to the spatial light modulator to control the adjustment of the light wave phase by the spatial modulator.
7. 5. The scanning device of claim 1, wherein the galvanometer mirror comprises a MEMS galvanometer mirror.
8. The scanning device according to claim 1, wherein the galvanometer includes at least one of a one-dimensional galvanometer and a two-dimensional galvanometer.
9. A scanning method, characterized in that the scanning method includes:

   Provide a scanning device, the scanning device according to any one of claims 1-8;

   Adjusting at least one of the vibration frequency and amplitude of the moving part of the galvanometer and the spatial light modulator adjusting the light wave phase size for scanning.
10. 9. The scanning method according to claim 9, wherein the amplitude of the galvanometer is increased when scanning a close target.
11. 9. The scanning method of claim 9, wherein the scanning device receives at least two incident light beams, and forms at least two scanning light beams emitted from the scanning device according to the at least two incident light beams;

    When scanning a close target, the spatial light modulator is controlled to splice the fields of view of the at least two scanning beams.
12. 9. The scanning method of claim 9, wherein the scanning device receives at least two incident light beams, and forms at least two scanning light beams emitted from the scanning device according to the at least two incident light beams;

    The scanning device includes at least two galvanometers and at least two spatial light modulators;

    The galvanometer mirror, the spatial light modulator, and the incident light beam have a one-to-one correspondence;

    When scanning a nearby target, the at least two spatial light modulators are controlled to splice the fields of view of the at least two scanning beams.
13. 9. The scanning method of claim 9, wherein when scanning a distant target, the amplitude of the galvanometer is reduced.
14. The scanning method according to claim 13, wherein the vibration frequency of the moving part of the galvanometer is increased.
15. 9. The scanning method of claim 9, wherein when receiving the detection signal, the spatial light modulator is adjusted according to the detection signal so that the beam propagation direction is toward the target to be detected.
16. 15. The scanning method of claim 15, wherein at least one of the vibration frequency and amplitude of the moving part of the galvanometer is adjusted according to the detection signal.
17. 9. The scanning method according to claim 9, wherein when receiving the complementary signal, the spatial light modulator is adjusted according to the complementary signal so that the beam propagation direction is toward the target to be detected.
18. 17. The scanning method of claim 17, wherein at least one of the vibration frequency and amplitude of the moving part of the galvanometer is adjusted according to the complement signal.
19. A laser radar is characterized in that it includes:

    A transmitting device, which generates an incident light beam;

    A scanning device, which receives an incident light beam and forms a scanning light beam according to the incident light beam, the scanning device according to any one of claims 1 to 8;

    At least part of the scanning beam is reflected by the target to be detected to form an echo beam;

    A receiving device, the receiving device receives the echo beam.
20. The laser radar according to claim 19, further comprising: a detection device connected to the scanning device, and the detection device generates a detection signal.
21. The lidar of claim 19, further comprising: an identification device connected to the receiving device, and the identification device determines the target to be detected based on the echo beam received by the receiving device is it complete;

    The recognition device is also connected to the scanning device, and when it is determined that the target to be detected is incomplete, the recognition device generates a complementary signal.

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