CN115980707A - Laser radar - Google Patents

Abstract

The application relates to the technical field of optical equipment correlation, in particular to a laser radar. Wherein, lidar includes: the emission module comprises a light-emitting unit and a scanning module; the light emitting unit is used for generating laser; the scanning module is used for changing the light path of the laser to scan the target; a receiving module for receiving the laser reflected or scattered by the target; the control module is in communication connection with the transmitting module and the receiving module and is used for controlling the transmitting module to transmit laser, controlling scanning parameters and acquiring scanning angle information and acquiring a scanning result related to a target based on the laser received by the receiving module; the laser reflected or scattered by the target is directly received by the receiving module without passing through the scanning module. Therefore, the laser emitted or scattered by the target does not pass through the scanning module but directly enters the receiving module, so that the emission and the receiving are completely decoupled, the complexity of the system is reduced, the installation and the adjustment are convenient, the receiving efficiency is improved, and the detection distance is further improved.

Description

Laser radar

Technical Field

The application relates to the technical field of optical equipment correlation, in particular to a laser radar.

Background

As is well known, the laser radar is a short term for a laser detection and ranging system, and analyzes information such as the magnitude of reflected energy, the amplitude, the frequency, the phase of a reflected spectrum, and the like on the surface of a target object by measuring the propagation distance between a sensor transmitter and the target object, thereby presenting accurate three-dimensional structural information of the target object. It is to be understood that the field angle of the laser radar is generally divided into a horizontal field angle and a vertical field angle, the horizontal field angle being an angle range that can be observed in the horizontal direction, and the vertical field angle being an angle range that can be observed in the vertical direction. The field angle determines the field of view that can be seen by the laser radar, and the larger the field angle, the larger the representative field of view, and conversely, the smaller the representative field of view.

In order to obtain a larger field of view by providing a larger field angle as much as possible in the conventional laser radar, a method of adding a scanning component to the laser radar system is often adopted, that is: the laser emitted by the emitting module is emitted to an external target object through the scanning module, and the laser reflected by the target object enters the receiving module after passing through the same scanning module again, so that a larger field angle is realized by scanning the emitting and receiving modules together or sharing the same scanning component.

However, such a structure known in the prior art greatly increases the complexity of the system, limits the flexibility of the overall architecture, and greatly reduces the reception efficiency of the echo because the echo must pass through the scanning component.

Disclosure of Invention

To overcome, at least to some extent, the problems in the related art, the present application provides a lidar.

The scheme of the application is as follows:

according to a first aspect of embodiments of the present application, there is provided a lidar comprising:

the emission module comprises a light-emitting unit and a scanning module; the light-emitting unit is used for generating laser; the scanning module is arranged on a laser emitting light path and used for changing the laser emitting light path to scan a target;

a receiving module for receiving laser light reflected or scattered by a target; and

the control module is in communication connection with the transmitting module and the receiving module and is used for controlling the transmitting module to transmit laser, controlling scanning parameters and acquiring scanning angle information and acquiring a scanning result related to a target based on the laser received by the receiving module;

the laser reflected or scattered by the target is directly received by the receiving module without passing through the scanning module.

In some embodiments, the light emitting unit is configured to emit a plurality of laser beams arranged in an mxn array;

the receiving module comprises a plurality of detectors which are arranged in an M multiplied by N array; each detector is used for receiving a corresponding target light beam; the target light beam is a laser beam which is emitted by the light-emitting unit and is reflected or scattered by a target.

In some embodiments, the detector is a silicon avalanche photodiode, a single photon avalanche diode, or a silicon photomultiplier tube.

In some embodiments, the receiving module further comprises: receiving a lens;

and the target light beams are emitted into the corresponding detector through the receiving lens.

In some embodiments, the receiving lens is a spherical or aspherical lens, a fresnel lens, or a microlens array for focusing the laser light.

In some embodiments, the light emitting unit comprises a laser and a beam splitter;

the laser is used for emitting laser;

the light splitter is used for splitting the laser emitted by the laser to obtain the multiple beams of laser arranged in an M multiplied by N array.

In some embodiments, the light emitting unit includes a plurality of light emitters;

the plurality of light emitters are arranged in an array and used for emitting the plurality of laser beams arranged in an M multiplied by N array.

In some embodiments, the light emitting unit further comprises:

and the emission lens is used for guiding the multiple laser beams to the scanning module.

In some embodiments, the scanning module comprises a turning mirror, a galvanometer, a turning mirror-galvanometer combination, or a MEMS.

The technical scheme provided by the application can comprise the following beneficial effects:

in the scheme in this application, only the laser transmission of the luminescence unit transmission among the emission module passes through the scanning module, and receiving module then direct reception by the laser of target reflection or scattering, promptly, the laser of being launched or scattering by the target does not pass through the scanning module but directly enters into receiving module, this makes and has realized launching and receiving complete decoupling, therefore has reduced the complexity of system, is convenient for the dress and transfers, and improved receiving efficiency, thereby improved detection distance, and the light path is simple, and stray light is few.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic structural diagram of a laser radar according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a laser radar according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a receiving module according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

Fig. 1 is a schematic structural diagram of a laser radar according to an embodiment of the present application, and referring to fig. 1, the laser radar according to the present application includes: the device comprises a transmitting module 1, a control module 3 and a receiving module 2; the emitting module 1 comprises a light emitting unit 11 and a scanning module 12; the light emitting unit 11 is used for generating laser; the scanning module 12 is arranged on a laser emitting optical path and used for changing the optical path of the laser to scan a target; the receiving module 2 is used for receiving the laser reflected or scattered by the target; the control module 3 is in communication connection with the emitting module 1 (specifically, the light emitting unit and the scanning module) and the receiving module 2, respectively, and is configured to control the emitting module 1 to emit laser, control scanning parameters and obtain scanning angle information, and obtain a scanning result about a target based on the laser received by the receiving module 2.

It is understood that the emission laser irradiates the target object by scanning, the irradiation power density of the laser can be increased to increase the detection distance, and the angle of field can be enlarged by scanning while securing high power density.

Advantageously, in the solution of the present application (see fig. 1), only the laser light emitted by the light emitting unit 11 in the emitting module 1 is transmitted through the scanning module 12, while the receiving module 2 directly receives the laser light reflected or scattered by the target, i.e. the laser light emitted or scattered by the target does not pass through the scanning module 12 but directly enters into the receiving module. This is quite different from the prior art mentioned in the background of the invention in the way in which the transmission and reception are scanned together.

Although the structural design of scanning emission and reception in the prior art allows a relatively large field angle to be obtained, the receiving efficiency is relatively low because the received laser passes through the scanning module, which is limited by the aperture of the scanning module, and the problem of relatively complex light path and much stray light is caused because the emission and reception share the scanning module and the coaxial light path design is needed.

However, the present invention provides an improved lidar system, which enables the receiving module 2 to directly receive the laser reflected or scattered by the target without passing through the scanning module, thereby achieving complete decoupling of transmission and reception, thus reducing the complexity of the system and facilitating installation and adjustment, and since the receiving module directly receives the laser without passing through the scanning module 12, the receiving efficiency can be improved, thereby improving the detection distance, and the lidar system has a simple optical path and little stray light.

In practical applications, as in the case of the lidar arrangement shown in fig. 1, to avoid as large a scan area and as large an angle of view as possible, limited by the size of the receiver's photosurface, the transmission and reception may be in the form of an array.

Specifically, the light emitting unit 11 is for emitting a plurality of laser lights arranged in an array; the receiving module 2 comprises a plurality of detectors 22; each detector 22 for receiving a corresponding target beam; the target light beam is a laser beam which is emitted by the light emitting unit 11 and is reflected or scattered by a target after passing through the scanning module 12.

In the present invention, for example, a plurality of laser beams emitted from the light emitting unit 11 may be configured as an M × N dot matrix, and the scanning of each light spot is only received by the pixels in the corresponding array, which are in a one-to-one relationship, that is, the receiving module correspondingly uses the M × N array, and all the pixels receive the echo at the same time. For example, the detector 22 included in the receiving module may be a silicon avalanche photodiode, a single photon avalanche diode, or an array of silicon photomultiplier tubes.

Thus, the scan module 12 may have a variety of options, for example, the scan module may include a turning mirror (e.g., a two-dimensional turning mirror), a galvanometer (e.g., a two-dimensional galvanometer), a combination of turning mirror and galvanometer, or MEMS.

The receiving module 2 further includes: a receiving lens 21; wherein the object beam is incident to the corresponding detector 22 through the receiving lens 21. The receiving lens 21 is, for example, a spherical or aspherical lens, a fresnel lens or a micro lens array, and is used for focusing laser light, so that light scattered or reflected by a target can be focused on the detector 22, and the detector 22 can receive the light to complete detection.

Fig. 2 and 3 are schematic diagrams illustrating an optical path of a lidar according to an embodiment of the present disclosure, and referring to fig. 2, a plurality of laser beams emitted by the light-emitting unit 11 form a 9 × 2 lattice, and the receiving module includes a plurality of detectors 22 and forms a 9 × 2 array. Two optical paths are shown in fig. 2. For example: the light beam emitted from the laser at the upper left corner of the light emitting unit 11 scans the upper left corner region of the scanning range 4 through the emission lens 111 and the scanning module 12. After scanning the target in the area, the light enters the detector 22 at the lower right corner through the receiving lens 21 by reflection or scattering of the target; the light beam emitted from the laser at the lower right corner of the light emitting unit 11 scans the lower right corner region of the scanning range 4 through the emission lens 111 and the scanning module 12. After the target in the area is scanned, light enters the detector 22 at the upper left corner through the receiving lens 21 by reflection or scattering of the target; with this arrangement, a larger angle of view can be obtained with a 9 × 2 array.

With continued reference to fig. 3, a schematic structural diagram of the receiving module according to an embodiment of the present application is shown, in which the detector 22 is a silicon Avalanche Photodiode (APD), the diameter D of the photosensitive surface is 1mm, the focal length L of the receiving lens 21 is 4mm, and θ =7.12 ° is calculated, that is, the combination of the APD and the receiving lens 21 can cover a field of view of about 14 ° × 14 °. Each detector 22 can cover a field of view in the range of 14 deg. by 14 deg., and the entire 9 x 2 array can cover a scan in the range of 126 deg. by 28 deg.. Correspondingly, the emission also adopts an arrayed structure, and the laser light-emitting array is 9 multiplied by 2, which can be obtained by splitting a single laser, can also be 18 laser diodes, and can also be a VCSEL array.

For example, the light emitting unit 11 may include a laser configured to emit laser light and a beam splitter configured to split the laser light emitted by the laser to obtain a plurality of laser lights arranged in an array. Alternatively, the light emitting unit 11 may include a plurality of light emitters; the plurality of light emitters are arranged in an array and used for emitting a plurality of beams of laser light arranged in an array. Wherein the light emitter may be a laser diode. Further, the light emitting unit 11 further includes: and the emission lens 111 is used for guiding the laser beams arranged in the multi-beam array to the scanning module 12 by the emission lens 111. Specifically, the emission lens 111 may be a spherical or aspheric lens, a fresnel lens or a microlens array, collimates each laser beam, and emits the collimated laser beam to the scanning module 12, the scanning module 12 is a rotating mirror, or a vibrating mirror, or a combination of a rotating mirror and a vibrating mirror, or an MEMS, so that the scanning range of each laser beam is 14 ° × 14 °, and the scanning range of each laser beam just falls within the field of view of a single detector 22 without interfering with each other. Through the design, the large-field-angle laser radar of 126 degrees multiplied by 28 degrees is realized, because the transmission adopts scanning, the laser power is higher, the receiving is not limited by the aperture of the scanning module 12, the higher detection distance can be obtained, the transmission and the receiving are completely decoupled, the system complexity is greatly reduced, and the installation and the adjustment are convenient.

In the description of the present specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims (9)

1. A lidar, comprising:

the emission module comprises a light-emitting unit and a scanning module; the light-emitting unit is used for generating laser; the scanning module is arranged on a laser emitting light path and used for changing the laser emitting light path to scan a target;

a receiving module for receiving laser light reflected or scattered by a target; and

the control module is in communication connection with the transmitting module and the receiving module and is used for controlling the transmitting module to transmit laser, controlling scanning parameters and acquiring scanning angle information and acquiring a scanning result related to a target based on the laser received by the receiving module;

the laser reflected or scattered by the target is directly received by the receiving module without passing through the scanning module.

2. The lidar of claim 1, wherein the light emitting unit is configured to emit a plurality of beams of laser light arranged in an mxn array;

the receiving module comprises a plurality of detectors which are arranged in an M multiplied by N array; each detector is used for receiving a corresponding target light beam; the target light beam is a laser beam which is emitted by the light-emitting unit and is reflected or scattered by a target.

3. The lidar of claim 2, wherein the detector is a silicon avalanche photodiode, a single photon avalanche diode, or a silicon photomultiplier.

4. The lidar of claim 2, wherein the receive module further comprises: receiving a lens;

and the target light beams are emitted into the corresponding detector through the receiving lens.

5. The lidar of claim 4, wherein the receiving lens is a spherical or aspherical lens, a Fresnel lens, or a micro lens array for focusing the laser light.

6. The lidar of claim 2, wherein the light emitting unit comprises a laser and a beam splitter;

the laser is used for emitting laser;

the light splitter is used for splitting the laser emitted by the laser to obtain the multiple beams of laser arranged in an MxN array.

7. The lidar of claim 2, wherein the light emitting unit comprises a plurality of light emitters;

the plurality of light emitters are arranged in an array and used for emitting the plurality of laser beams arranged in an M multiplied by N array.

8. The lidar of claim 2, wherein the light emitting unit further comprises:

and the emission lens is used for guiding the multiple laser beams to the scanning module.

9. The lidar of claim 2, wherein the scanning module comprises a turning mirror, a vibrating mirror, a turning mirror-vibrating mirror combination, or a MEMS.

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