WO2022040937A1

WO2022040937A1 - Laser scanning device and laser scanning system

Info

Publication number: WO2022040937A1
Application number: PCT/CN2020/111149
Authority: WO
Inventors: 王昊; 韩国庆; 王闯; 龙承辉
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2022-03-03
Also published as: CN114503007A; CN114503007B

Abstract

A laser scanning device (100) and a laser scanning system (1000). The laser scanning device (100) comprises a light source (10), a first light refraction element (20), and a second light refraction element (30) or a light reflection element (40), wherein light emitted by the light source (10) is emitted after sequentially passing through the first light refraction element (20) and the second light refraction element (30) or the light reflection element (40); and the first light refraction element (20) and the second light refraction element (30) or the light reflection element (40) can rotate to change the emergent angle of light. The laser scanning device (100) has a first scanning mode and a second scanning mode. The field angle of the laser scanning device (100) in the first scanning mode is different from the field angle of the laser scanning device in the second scanning mode; and/or the point cloud coverage uniformity of the laser scanning device (100) in the first scanning mode is different from the point cloud coverage uniformity of the laser scanning device in the second scanning mode; and/or the point cloud coverage integrity of the laser scanning device (100) in the first scanning mode is different from the point cloud coverage integrity of the laser scanning device in the second scanning mode.

Description

Laser Scanning Devices and Laser Scanning Systems

technical field

The present application relates to the technical field of laser scanning, and in particular, to a laser scanning device and a laser scanning system.

Background technique

At present, lidars are usually installed on mobile platforms such as drones to scan and map the terrain. In related technologies, lidars installed on mobile platforms such as drones usually only have a single scanning mode, which cannot meet the needs of different scenarios. requirements for scanning and mapping.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a laser scanning device and a laser scanning system.

The laser scanning device according to the embodiment of the present application includes a light source, a first light refraction element, and a second light refraction element or a light reflection element. Light emitted by the light source passes through the first light refraction element and the second light refraction element in sequence. After the light refraction element or the light reflection element is emitted, the first light refraction element and the second light refraction element or the light reflection element can be rotated to change the exit angle of the light;

Wherein, the laser scanning device has a first scanning mode and a second scanning mode, and the field angle of the laser scanning device in the first scanning mode is different from that in the second scanning mode; and / or

The point cloud coverage uniformity of the laser scanning device in the first scan mode is different from the point cloud coverage uniformity in the second scan mode; and/or

The point cloud coverage integrity of the laser scanning device in the first scan mode is different from the point cloud coverage integrity in the second scan mode.

The laser scanning system of the embodiment of the present application includes:

mobile platforms; and

In the laser scanning device of the above embodiment, the laser scanning device is installed on the moving platform, and the moving platform is used to drive the laser scanning device to move to scan an object.

In the laser scanning device and the laser scanning system according to the embodiments of the present application, the laser scanning device has a first scanning mode and a second scanning mode, and the field angle and point cloud of the laser scanning device in the first scanning mode and the second scanning mode There is at least one difference between coverage uniformity and point cloud coverage integrity. In this way, the user can select different scanning modes for scanning according to different scanning scenarios, so as to meet the needs of scanning and mapping for different scenarios and improve the user experience.

Additional aspects and advantages of the embodiments of the present application will be set forth, in part, in the following description, and in part will be apparent from the following description, or learned by practice of the embodiments of the present application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic structural diagram of a laser scanning device according to an embodiment of the present application;

FIG. 2 is another schematic structural diagram of the laser scanning device according to an embodiment of the present application;

3 is a schematic diagram of a module of a laser scanning device according to an embodiment of the present application;

4 is a schematic diagram of a scanning pattern of the laser scanning device in FIG. 1 in a first scanning mode;

Fig. 5 is the point cloud schematic diagram of the laser scanning device in Fig. 1 under the first scanning mode;

6 is a schematic diagram of a scanning pattern of the laser scanning device in FIG. 1 in a second scanning mode;

Fig. 7 is the point cloud schematic diagram of the laser scanning device in Fig. 1 under the second scanning mode;

8 is a schematic diagram of a scanning pattern of the laser scanning device in FIG. 1 in a third scanning mode;

Fig. 9 is the point cloud schematic diagram of the laser scanning device in Fig. 1 under the third scanning mode;

10 is a schematic plan view of a scanning pattern of the laser scanning device in FIG. 2 in a first scanning mode;

11 is a schematic perspective view of a scanning pattern of the laser scanning device in FIG. 2 in a first scanning mode;

12 is a schematic plan view of a scanning pattern of the laser scanning device in FIG. 2 in a second scanning mode;

13 is a schematic perspective view of a scanning pattern of the laser scanning device in FIG. 2 in a second scanning mode;

14 is a schematic plan view of a scanning pattern of the laser scanning device in FIG. 2 in a third scanning mode;

15 is a perspective view of a scanning pattern of the laser scanning device in FIG. 2 in a third scanning mode;

FIG. 16 is a schematic structural diagram of a laser scanning system according to an embodiment of the present application.

detailed description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present application, and should not be construed as a limitation on the present application.

In the description of the present application, it should be understood that the terms "first" and "second" are only used for description purposes, and cannot be interpreted as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, features defined as "first", "second" may expressly or implicitly include one or more of said features. In the description of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; it can be a mechanical connection, an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction of two elements relation. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples and are not intended to limit the application. Furthermore, this application may repeat reference numerals and/or reference letters in different instances for the purpose of simplicity and clarity, and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, this application provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

Referring to FIGS. 1 and 2 , the laser scanning device 100 according to the embodiment of the present application includes a light source 10 , a first light refraction element 20 , and a second light refraction element 30 or a light reflection element 40 , and the light emitted by the light source 10 passes through the first The light refraction element 20 and the second light refraction element 30 or the light reflection element 40 exit after the light refraction element 20 and the second light refraction element 30 or the light reflection element 40 can be rotated to change the exit angle of the light. Wherein, the laser scanning device 100 has a first scanning mode and a second scanning mode, and the field angle of the laser scanning device 100 in the first scanning mode is different from that in the second scanning mode; and/or

The point cloud coverage uniformity of the laser scanning device 100 in the first scan mode is different from the point cloud coverage uniformity in the second scan mode; and/or

The point cloud coverage integrity of the laser scanning device 100 in the first scan mode is different from the point cloud coverage integrity in the second scan mode.

At present, lidars are usually installed on mobile platforms such as UAVs to scan and map the terrain. In the field of lidar surveying and mapping, lidar's field of view, point cloud coverage uniformity, and point cloud coverage integrity directly affect the scanning effect. . In related technologies, lidars installed on mobile platforms such as drones usually only have a single scanning mode, and their point cloud coverage uniformity and point cloud coverage integrity remain basically unchanged, which cannot meet the requirements of scanning and mapping for different scenarios. demand.

In the laser scanning device 100 according to the embodiment of the present application, the laser scanning device 100 has a first scanning mode and a second scanning mode, and the field angle and point cloud coverage of the laser scanning device 100 in the first scanning mode and the second scanning mode There is at least one difference between uniformity and point cloud coverage integrity. In this way, the user can select different scanning modes for scanning according to different scanning scenarios, so as to meet the needs of scanning and mapping for different scenarios and improve the user experience.

It should be noted that, in the embodiments of the present application, "point cloud coverage uniformity" refers to the uniformity of point cloud coverage at different positions within the field of view during a scanning process, and the point cloud coverage is the number of point clouds per unit area of the scanned object. "Point cloud coverage integrity" refers to the completeness of the point cloud coverage on the scanned object. In addition, it should be noted that the above "point cloud coverage uniformity" and "point cloud coverage integrity" are obtained on the basis of the same sampling rate and the same time, that is, points within a large range are guaranteed. In the case of the same cloud density, the uniformity of point cloud coverage and the completeness of point cloud coverage in each scanning mode.

In the embodiments of the present application, the laser scanning device 100 may be electronic devices such as lidar and laser ranging equipment, and the laser scanning device 100 may be used to sense external environmental information, such as distance information, azimuth information, reflection intensity of environmental targets information, speed information, etc. The point cloud points measured by the laser scanning device 100 may include distance information, azimuth information, reflection intensity information, speed information, etc. of the environmental target of the laser scanning device 100 .

In an implementation manner, the laser scanning device 100 can detect the detection object to the laser scanning device by measuring the time of light propagation between the laser scanning device 100 and the detection object, that is, the Time-of-Flight (TOF) of light 100 distance. Alternatively, the laser scanning device 100 can also detect the distance from the detected object to the laser scanning device through other techniques, such as a ranging method based on phase shift measurement, or a ranging method based on frequency shift measurement, There is no restriction here. The distance and orientation detected by the laser scanning device 100 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.

Referring to FIG. 1 , in the embodiment of the present application, the light source 10 can generate a laser beam. For example, the laser beam can be a single laser pulse or a series of laser pulses. In addition, the laser scanning device 100 further includes a collimating element 50, and the collimating element 50 is used for collimating the laser beam generated by the light source 10. The collimated light refers to the light having parallel rays, and the parallel rays are substantially will not spread.

In the embodiment of the present application, the collimated light enters the first light refraction element 20 and the second light refraction element 30 or the light reflection element 40 in sequence and then exits. Referring to FIG. 1 and FIG. 2 , in the embodiment of the present application, the laser scanning device 100 may further include a detector 60 and a beam splitter 70 . The beam splitter 70 is installed between the collimating element 50 and the light source 10 . The light source 10 The emitted light can pass through the beam splitter 70 and be collimated by the collimating element 50 and then enter the first light refraction element 20. When the beam emitted by the laser scanning device 100 hits the scanning object, the light is reflected back and passes through the beam splitter. 70 is received by the detector 60 after being reflected.

For ease of understanding, please refer to FIG. 1 and FIG. 2 , the module composed of the light source 10 , the collimating element 50 , the detector 60 and the beam splitter 70 may be referred to as a ranging module 110 , the first light refraction element 20 and the second The module composed of the light refraction element 30 or the light reflection element 40 is called a scanning module 120 . The ranging module 110 is used for emitting a light beam, receiving the returning light, and converting the returning light into an electrical signal. Therein, the light source 10 may be used to emit a sequence of light pulses. In one embodiment, the light source 10 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the light source 10 is a narrow bandwidth beam with a wavelength outside the visible light range. The collimating element 50 is disposed on the outgoing light path of the light source 10 for collimating the light beam emitted from the light source 10 , and collimating the light beam emitted by the light source 10 into parallel light and emitting to the scanning module 120 . The collimating element 50 also serves to converge at least a portion of the return light reflected by the probe. The collimating element 50 may be a collimating lens or other elements capable of collimating light beams. The scanning module 120 is placed on the outgoing light path of the ranging module 110, and the scanning module 120 is used to change the transmission direction of the collimated beam emitted by the collimating element 50 and project it to the external environment, and project the return light to the collimating element 50, The returned light passes through the collimating element 50 and is collected on the detector 60 by the beam splitter 70 .

Specifically, referring to FIG. 3 , in a possible implementation manner, the light source 10 may include a transmitting circuit 11 , and the detector 60 may include a receiving circuit 61 , a sampling circuit 62 and an arithmetic circuit 63 . Specifically, the transmitting circuit 11 of the light source 10 may transmit a sequence of light pulses (eg, a sequence of laser pulses). The receiving circuit 61 of the detector can receive the optical pulse sequence reflected by the detected object, and perform photoelectric conversion on the optical pulse sequence to obtain an electrical signal, which can be output to the sampling circuit 62 after processing the electrical signal. The sampling circuit 62 can sample the electrical signal to obtain a sampling result. The arithmetic circuit 63 may determine the distance between the laser scanning device 100 and the detected object based on the sampling result of the sampling circuit 62 .

Optionally, the laser scanning device 100 may further include a control circuit 64, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.

It can be understood that although the laser scanning device 100 shown in FIG. 3 includes a transmitting circuit 11 , a receiving circuit 61 , a sampling circuit 62 and an arithmetic circuit 63 for emitting a beam of light for detection, the embodiment of the present application does not Limited to this, the number of any one of the transmitting circuit 11, the receiving circuit 61, the sampling circuit 62, and the arithmetic circuit 63 may also be at least two, for emitting at least two beams in the same direction or in different directions respectively; wherein , the at least two beam paths may be emitted at the same time, or may be emitted at different times respectively. In one example, the light-emitting chips in the at least two emission circuits 11 are packaged in the same module. For example, each emitting circuit 11 includes a laser emitting chip, and the laser emitting chips in the at least two emitting circuits 11 are packaged together and accommodated in the same packaging space.

In addition, the laser scanning device 100 of the present application may adopt a coaxial optical path, that is, the light beam emitted by the laser scanning device 100 and the reflected light beam share at least part of the optical path in the laser scanning device 100 . For example, after at least one laser pulse sequence emitted by the transmitting circuit 11 changes its propagation direction through the scanning module 120 , the laser pulse sequence reflected by the detected object passes through the scanning module 120 and then enters the receiving circuit 61 . Alternatively, the laser scanning device 100 can also use an off-axis optical path, that is, the light beam emitted by the laser scanning device 100 and the reflected light beam are transmitted along different optical paths in the laser scanning device 100, which are not specifically limited here.

In the embodiments shown in FIG. 1 and FIG. 2 , the transmitting optical path and the receiving optical path share the same collimating element 50 , which makes the optical path more compact. In some other implementations, the light source 10 and the detector 60 may also use their own collimating elements, which are not specifically limited herein.

Additionally, in such an embodiment, the beam splitter 70 may include a mirror having an opening that may allow light from the light source 10 to pass through, while the mirror portion of the beam splitter 70 may direct the returning light toward the detection reflector 60 so that the detector 60 receives the reflected light. In embodiments of the present application, the detector 60 may receive the returned light and convert the light into an electrical signal. For example, the detector 60 may include an avalanche photodiode (APD), which is a highly sensitive semiconductor electronic device, that converts light into an electrical signal by exploiting the photocurrent effect.

In addition, referring to FIG. 2 , taking the scanning module 120 including the first photorefractive element 20 and the second photorefractive element 30 as an example, the scanning module 120 may further include a driver (not shown) connected to the first photorefractive element 20 , The driver is used to drive the first light refraction element 20 to rotate, so that the first light refraction element 20 changes the direction of the collimated beam collimated by the collimation element 50 . The first light refraction element 20 projects the collimated light beams to different directions. In one embodiment, the first light-refractive element 20 includes a pair of opposing non-parallel surfaces through which the collimated light beam passes. In one embodiment, the first light-refractive element 20 comprises prisms of varying thickness along at least one radial direction. In one embodiment, the first light-refractive element 20 includes a wedge-angle prism to refract the collimated light beam.

In such an embodiment, the second light refraction element 30 can also rotate around the rotation axis of the first light refraction element 20 , and the rotation speed of the second light refraction element 30 may be different from the rotation speed of the first light refraction element 20 . The second light refraction element 30 is used to change the direction of the light beam projected by the first light refraction element 20 . In one embodiment, the second light refraction element 30 is connected with another driver, and the driver drives the second light refraction element 30 to rotate. It can be understood that, the first light refraction element 20 and the second light refraction element 30 may be driven by the same or different drivers, so that the rotational speed and/or rotation of the first light refraction element 20 and the second light refraction element 30 are different, so that the The collimated beam collimated by the collimating element 50 is projected to different directions in the external space, and can scan a large spatial range. In one embodiment, the rotational speed of the first light refraction element 20 and the second light refraction element 30 may be determined according to the area and pattern expected to be scanned in practical applications, and the driver may include a motor or other drivers.

In one embodiment, the second light-refractive element 30 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, the second light-refractive element 30 comprises prisms of varying thickness along at least one radial direction. In one embodiment, the second light refractive element 30 comprises a wedge prism.

It can be understood that when the scanning module 120 includes the first light refraction element 20 and the light reflection element 40, its specific scanning working principle is basically the same as the above, the difference is that the light reflection element 40 is used to pass through the first light refraction element. 20Refracted light is reflected to cast light in different directions.

The rotation of each optical element in the scanning module 120 can project light in different directions, thus scanning the space around the laser scanning device 100. As shown in FIG. 4 , FIG. 4 is a schematic diagram of a scanning pattern of the laser scanning device 100 . It can be understood that when the speed of the optical element in the scanning module 120 changes, the scanning pattern also changes accordingly.

It can be understood that, in the embodiment of the present application, when the light projected by the scanning module 120 hits the probe, a part of the light is reflected by the probe to the laser scanning device 100 in a direction opposite to the projected light. The returning light reflected by the probe passes through the scanning module 120 and then enters the collimating element 50 . A detector 205 is placed on the same side of the collimating element 204 as the light source 10, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.

In one embodiment, each optical element is coated with an anti-reflection film, that is, the first light-refractive element 20 and the second light-refractive element 30 may be coated with an anti-reflection film. Optionally, the thickness of the anti-reflection film is equal to or close to the wavelength of the light beam emitted by the light source 10, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is coated on the surface of an element located on the beam propagation path in the laser scanning device 100, or a filter is provided on the beam propagation path, for transmitting at least the wavelength band of the light beam emitted by the light source 10. , and reflect other wavelength bands to reduce the noise brought by ambient light to the detector 60 .

In some embodiments, the light source 10 may comprise a laser diode through which laser pulses are emitted at the nanosecond scale. Further, the laser pulse receiving time can be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse to determine the laser pulse receiving time. In this way, the laser scanning device 100 can use the pulse receiving time information and the pulse sending time information to calculate the TOF, so as to determine the distance from the probe 201 to the laser scanning device 100 .

It can be understood that, in the embodiments of the present application, the distance and orientation detected by the laser scanning device 100 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In one embodiment, the laser scanning device 100 of the embodiment of the present application can be applied to a mobile platform, and the laser scanning device 100 can be installed on the platform body of the mobile platform. The mobile platform with the laser scanning device 100 can measure the external environment, for example, measure the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and perform two-dimensional or three-dimensional mapping of the external environment.

In some embodiments, the mobile platform includes at least one of a drone, a car, a remote control car, a robot, and a camera. When the laser scanning device 100 is applied to the unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle. When the laser scanning device 100 is applied to an automobile, the platform body is the body of the automobile. The vehicle may be an autonomous driving vehicle or a semi-autonomous driving vehicle, which is not limited herein. When the laser scanning device 100 is applied to a remote control car, the platform body is the body of the remote control car. When the laser scanning device 100 is applied to a robot, the platform body is a robot. When the laser scanning device 100 is applied to a camera, the platform body is the camera itself.

Referring to FIG. 1 , in some embodiments, the laser scanning device 100 includes a first light refraction element 20 and a second light refraction element 30 , and the first light refraction element 20 includes opposite and non-parallel first light incident surfaces 21 and 30 The first light exit surface 22 and the second light refraction element 30 include a second light entrance surface 31 and a second light exit surface 32 that are opposite and non-parallel. The light emitted by the light source 10 passes through the first light entrance surface 21 and the first light exit surface 22 in sequence. and the second light incident surface 31 and then exit through the second light exit surface 32 .

In this way, the light emitted by the light source 10 can be refracted by the two rotatable light refraction elements, and then the exit angle of the light can be changed.

Referring to FIGS. 4 to 7 , in such an embodiment, the field angle of the laser scanning device 100 in the first scanning mode is larger than that in the second scanning mode. The point cloud coverage uniformity of the laser scanning device 100 in the first scanning mode is smaller than the point cloud coverage uniformity in the second scanning mode.

In this way, when different scenes need to be scanned, different scanning modes can be selected for scanning to optimize the scanning results. For example, due to the larger field of view in the first scanning mode, the scanning coverage of the laser scanning device 100 can be larger, and a lot of information about the object can be obtained by scanning to improve the coverage integrity. Therefore, in the scene to be scanned When there are many features such as vertical walls or pipes, the first scanning mode can cover a wider range, and the images obtained by scanning are relatively complete. Furthermore, the point cloud coverage in the second scanning mode is more uniform, and the point cloud distribution is relatively uniform, which is suitable for scenes with high requirements on the uniformity of point cloud coverage, such as agricultural and forestry surveying and mapping, construction site monitoring, and landslide surveying and mapping.

Further, referring to FIGS. 4 to 7 , in such an embodiment, the point cloud coverage integrity of the laser scanning device 100 in the first scan mode is greater than that in the second scan mode.

In this way, when the scene to be scanned has a high requirement for the completeness of point cloud coverage, the first scanning mode can be used for scanning. , the second scanning mode can be used for scanning, so that the laser scanning device 100 can adapt to different scanning scenarios.

Specifically, please refer to 4 and FIG. 7, FIG. 4 is a schematic diagram of a scanning pattern under the first scanning mode, FIG. 5 is a point cloud diagram under the first scanning mode, and FIG. 6 is a schematic diagram of the scanning pattern under the second scanning mode, Fig. 7 is the point cloud image in the second scanning mode. Comparing Fig. 4 and Fig. 6 and comparing Fig. 5 and Fig. 7, it can be seen that in the second scanning mode, the point cloud coverage is more uniform, and the point cloud coverage in the second scanning mode is uniform. The degree of coverage is greater than the uniformity of point cloud coverage in the first scan mode. In the first scan mode, the completeness of the point cloud coverage is greater, that is, the completeness of the point cloud coverage in the first scan mode is greater than that in the second scan mode. Different scanning modes can be selected to cover different requirements of completeness, which improves the user experience.

Referring to FIG. 1 , in some embodiments, in the first scanning mode, the rotational speed of the first light refraction element 20 is different from the rotational speed of the second light refraction element 30 . In the second scanning mode, the rotation speed of the first light refraction element 20 is the same as that of the second light refraction element 30 , and the rotation direction of the first light refraction element 20 is opposite to the rotation direction of the second light refraction element 30 .

In this way, the laser scanning device 100 can have the first scanning mode and the second scanning mode by designing the rotational speed and the rotational direction of the first and second light refracting elements 30 , and the implementation is relatively simple.

Specifically, in this embodiment, setting the rotational speed of the first photorefractive element 20 to be different from that of the second photorefractive element 30 can make the field of view of the first scanning mode larger than the field of view of the second scanning mode angle, and the point cloud coverage integrity in the first scan mode is greater than the point cloud coverage integrity in the second scan mode. Reverse rotation of the rotation speed of the first light refraction element 20 and the equal speed of the second light refraction element 30 can make the point cloud coverage uniformity of the second scanning mode greater than the coverage uniformity of the first scanning mode.

Referring to FIGS. 8 and 9 , in an embodiment, the laser scanning device 100 further has a third scanning mode, and the field angle of the laser scanning device 100 in the third scanning mode is the same as the field angle in the first scanning mode same. The point cloud coverage uniformity of the laser scanning device 100 in the third scan mode is greater than the point cloud coverage uniformity in the first scan mode, and smaller than the point cloud coverage uniformity in the second scan mode.

In this way, when the scene to be scanned has high requirements on the field of view and the uniformity of point cloud coverage, the third scanning mode can be selected to scan the scene to be scanned. When the tower is inspected, the pipeline is inspected, and the corridor is surveyed, the third scanning mode can be preferentially selected for scanning to optimize the scanning results.

Further, in such an embodiment, the point cloud coverage integrity of the laser scanning device 100 in the third scan mode is the same as the point cloud coverage integrity in the first scan mode and greater than the point cloud coverage in the second scan mode Cloud coverage integrity.

In this way, the use of the third scanning mode can also obtain a larger coverage integrity of the point cloud, which can further optimize the scanning results.

Specifically, please refer to 8 and FIG. 9 , FIG. 8 is a schematic diagram of the scanning pattern under the third scanning mode, FIG. 9 is the point cloud image under the third scanning mode, compare FIGS. 4 , 6 and 8 and compare FIGS. 5 , 7 and 9, it can be seen that the uniformity of point cloud coverage in the third scan mode is greater than that in the first scan mode, but slightly smaller than that in the second scan mode. The point cloud coverage integrity in the third scan mode is basically the same as that in the first scan mode. Therefore, when scanning a scene with high requirements for point cloud coverage uniformity and point cloud coverage integrity, you can The third scan mode is preferred. It should be noted that the Y-axis direction in FIGS. 4 to 9 represents the movement direction of the laser scanning device 100 , that is, when the laser scanning device 100 is mounted on a mobile platform such as an unmanned aerial vehicle to move The direction of movement, the X-axis direction is perpendicular to the movement direction.

Referring to FIG. 1 , in this embodiment, in the third scanning mode, the rotational speed of the first light refraction element 20 is the same as the rotational speed of the second light refraction element 30 , and the first light refraction element The rotation direction of 20 is the same as the rotation direction of the second light refraction element 30 .

In this way, the first refraction element and the second light refraction element 30 can be designed to rotate in the same direction at the same speed, so that the laser scanning device 100 has a third angle of view, point cloud coverage uniformity and point cloud coverage integrity. Scanning mode, so that the laser scanning device 100 can adapt to more scanning scenarios.

In some embodiments, in the third scanning mode, the laser scanning device 100 repeatedly scans along the circular trajectory for a period of time corresponding to one frame of point cloud image.

In this way, in the third scanning mode, the laser scanning device 100 repeatedly scans along the circular trajectory for many times, so that the uniformity of the point cloud coverage and the completeness of the point cloud coverage can reach a higher level, and the scanning quality can be optimized, which is suitable for point cloud coverage. Scanning is performed on occasions with high requirements for cloud coverage uniformity and point cloud coverage integrity.

Referring to FIG. 5 , in some embodiments, in the first scanning mode, the laser scanning device 100 has a higher density in the central area of the scanning pattern than in the peripheral area in a time period corresponding to one frame of point cloud image.

In this way, although the density of the central area is higher than the density of the peripheral area, the uniformity of the point cloud coverage will be lower, but the point cloud coverage of the laser scanning device 100 is relatively complete, which is suitable for applications with low requirements for the uniformity of point cloud coverage. And scan for occasions that require high point cloud coverage integrity, such as pipeline inspection, etc.

It should be noted that, in this embodiment, the "scanning pattern" refers to the scanning pattern when the laser scanning device 100 is stationary, and the scanning pattern is determined by the motion pattern of the scanning element of the laser scanning device 100. That is, the scanning pattern is determined by the rotation speed and rotation direction of the first light refraction element 20 and the second light refraction element 30 . In the following embodiments, if there are similar or identical descriptions, it can also be understood with reference to this.

Further, in some embodiments, in the first scanning mode, the laser scanning device 100 scans along the scanning pattern only once in a time period corresponding to one frame of point cloud image.

In this way, in the first scanning mode, the laser scanning device 100 performs non-repetitive scanning, which can make the coverage of the point cloud more complete.

In some embodiments, in the third scanning mode, the laser scanning device 100 repeatedly scans along a scanning trajectory for a period of time corresponding to one frame of point cloud image, wherein the scanning trajectory in the first scanning mode is compared with the scanning trajectory in the first scanning mode. The scanning density of the scanning track in the three-scanning mode is higher in one of the directions. It is understood that the number of times may be two or more times, which is not specifically limited herein.

In this way, the scanning trajectories in the first scanning mode have a higher scanning density in one of the directions than the scanning trajectories in the third scanning mode, so that the third scanning mode has more uniform point cloud coverage than the first scanning mode Spend.

In some embodiments, in the second scanning mode, the laser scanning device 100 repeatedly scans along one scanning trajectory for a period of time corresponding to one frame of point cloud image.

In this way, in the second scanning mode, the laser scanning device 100 repeatedly scans along one scanning track for many times, so that the uniformity of the point cloud coverage can be higher.

In some embodiments, in the first scanning mode, the scanning patterns of the laser scanning device 100 in two adjacent frames of point cloud images are different. In this way, the laser scanning device 100 performs non-repetitive scanning, and its point cloud coverage is relatively complete.

In some embodiments, in the second scanning mode, the scanning patterns of the laser scanning device 100 in two adjacent frames of point cloud images are the same.

In this way, the laser scanning device 100 performs repeated scanning, and the uniformity of the point cloud coverage is relatively large.

It can be understood that, in the embodiment of the present application, the scanning pattern is an inherent pattern when the laser scanning device 100 is stationary, which depends on the rotation of the first light refraction element 20 and the second light refraction element 30 or the light reflection element 40 speed and direction of rotation. The point cloud image depends on the distribution and scanning pattern of the objects in the scanning environment, and the point cloud image will change with the changes of the objects in the scanning environment.

Referring to FIG. 2 , in some embodiments, the laser scanning device 100 includes a first light refraction element 20 and a light reflection element 40 , and the first light refraction element 20 includes a first light incident surface 21 and a first light exit surface that are opposite and non-parallel On the surface 22, the light reflecting element 40 includes a reflecting surface. After the light source 10 emits light, the light passes through the first light incident surface 21 and the first light exit surface 22 in sequence, and then is emitted by the reflecting surface 41 and then exits.

In this way, the light emitted by the light source 10 can be refracted and reflected by the rotatable first light refraction element 20 and the light reflection element 40 to change the exit angle of the light. Specifically, in such an embodiment, the first light refraction element 20 may be an optical element such as a triangular prism, and the light reflection element 40 may be a reflector.

Further, in such an embodiment, in the first scanning mode, the rotational speed of the first light refracting element 20 is greater than the rotational speed of the light reflecting element 40 . In the second scanning mode, the rotational speed of the first light refraction element 20 is the same as the rotational speed of the light reflection element 40 .

Specifically, in the first scanning mode, the rotational speed of the first light refracting element 20 is greater than the rotational speed of the light reflective element 40, and in this case, the resolution in the horizontal direction depends on the first light refracting element 20 and the light reflective element The speed of the rotational speed of the driving motor 40 and the resolution in the vertical direction depend on the repetition frequency of the light source 10 . Please refer to FIGS. 10 and 11. FIG. 10 is a schematic plan view of the scanning pattern in the first scanning mode. It can be seen from the figures that in the first scanning mode, the resolution in the vertical direction of the scanning pattern is higher than that in the horizontal direction. It is more suitable for detecting and identifying objects whose horizontal length is higher than vertical length.

In the second scanning mode, the rotational speed of the first light refracting element 20 is substantially equal to the rotational speed of the light reflecting element 40. In this case, the resolution in the horizontal direction depends on the repetition frequency of the light source 10, and the resolution in the vertical direction The resolution depends on the rotational speeds of the driving motors of the first light refraction element 20 and the light reflection element 40 . Please refer to FIGS. 12 and 13 . FIG. 12 is a schematic plan view of the scanning pattern in the second scanning mode. It can be seen from the figures that in the second scanning mode, the rotational speed of the first light refracting element 20 and the rotation of the light reflecting element 40 are The same speed can make the resolution rate in the horizontal direction of the scanning pattern higher than that in the vertical direction, which is more suitable for detecting and identifying objects whose horizontal length is less than the vertical height. In this way, users can choose different scanning modes according to different scenarios. To meet different requirements, or the laser scanning device 100 can automatically enter an adapted scanning mode according to the type of the scene to be scanned.

Further, in such an embodiment, the laser scanning device 100 further has a third scanning mode. In the third scanning mode, the rotational speed of the first light refracting element 20 is lower than the rotational speed of the light reflecting element 40 .

In this way, in the third scanning mode, the rotation speed of the first light refraction element 20 is lower than the rotation speed of the light reflection element 40, which can make the vertical resolution and horizontal resolution of the scanning pattern more balanced, which is more suitable for the horizontal resolution and vertical resolution. Uniform resolution must be required for scenes. Specifically, please refer to FIGS. 14 and 15 . It can be seen from FIGS. 14 and 15 that in the third scanning mode, the scanning pattern is in the shape of a fishnet, and the resolution in the horizontal direction and the resolution in the vertical direction are relatively balanced.

In some embodiments, the laser scanning device 100 is used to switch the scanning mode based on the user's operation.

In this way, the user can freely select and switch the scanning mode according to the scene to be scanned, which improves the user experience. Specifically, in an example, when it is necessary to scan a scene with many vertical walls or to perform an inspection of a pipeline, the user can select the first scan mode to scan.

In some embodiments, the laser scanning device 100 can also be used to select a corresponding scanning mode according to the recognition of the scanning environment.

In this way, the laser scanning device 100 can identify the scanning scene according to the scanning of the environment, and then automatically select a scanning mode corresponding to the scene to scan, which improves the intelligence of the laser scanning device 100 . Specifically, in an example, when the laser scanning device 100 scans and identifies that there are many vertical walls or pipes in the scanning environment, the laser scanning device 100 automatically enters the first scanning mode or the third scanning mode to scan.

In addition, in some embodiments, the laser scanning device 100 may be used to recommend a corresponding scanning mode to the user according to the recognition of the scanning environment, and determine the scanning mode based on the user's operation.

In this way, the laser scanning device 100 can identify the scanning scene according to the scanning of the environment, and then recommend to the user which scanning mode to use, and determine the scanning mode to scan when the user performs an operation. In this way, the laser scanning device 100 can automatically recommend to the user The scanning mode is available for the user to choose, which improves the user experience. Specifically, in one example, when the laser scanning device 100 scans and identifies that there are many vertical walls or pipes in the scanning environment, the laser scanning device 100 may recommend the first scanning mode and the third scanning mode to the user to for the user to choose.

Referring to FIG. 16 , the laser scanning system 1000 of the embodiment of the present application includes a mobile platform 200 and the laser scanning device 100 of any of the above embodiments. The laser scanning device 100 is installed on the mobile platform 200 , and the mobile platform 200 is used to drive the laser scanning device. 100 moves to scan the object.

In the laser scanning system 1000 of the embodiment of the present application, the laser scanning device 100 has a first scanning mode and a second scanning mode, and the field angle and point cloud coverage of the laser scanning device 100 in the first scanning mode and the second scanning mode There is at least one difference between uniformity and point cloud coverage integrity. In this way, users can select different scanning modes for scanning according to different scanning scenarios, so as to meet the needs of scanning and mapping for different scenarios and improve user experience.

Specifically, in the illustrated embodiment, the mobile platform 200 is a drone. It can be understood that in other embodiments, the mobile platform 200 includes but is not limited to drones, vehicles, mobile carts, and mobile robots that can drive laser light. The scanning device 100 is a mobile device that moves to implement scanning, mapping or ranging.

Referring to FIG. 16 , in at least one of the scanning modes, the field of view includes a first field of view angle α along the straight forward direction of the moving platform 200 and a second field of view angle β along the straight forward direction perpendicular to the moving platform 200 , the second angle of view β is greater than or equal to the first angle of view α.

In this way, the larger second field of view angle β can enable the laser scanning system 1000 to obtain a larger scanning range in the direction perpendicular to the front of the moving platform 200, thereby improving the scanning efficiency.

Specifically, in the embodiments of the present application, the forward direction of the mobile platform 200 may be understood as the moving direction of the mobile platform 200, for example, the flight direction of the drone.

In some embodiments, in the first scanning mode, the first field of view angle α of the laser scanning device 100 is between 138°-142°, and the second field of view angle β is between 138°-142° .

In this way, in the first scanning mode, the first angle of view α and the second angle of view β of the laser scanning device 100 are both larger, so that the coverage of the point cloud can be larger.

Specifically, in the embodiments of the present application, in the first scanning mode, the first field of view angle α and the second field of view angle β are preferably 140°. Of course, in other embodiments, the first field of view angle is 140°. The angle α and the second angle of view β can also be other values, and they can be the same or different. For example, the first angle of view α can be any one of 138°, 139°, 141°, and 142°, or Other values between 138°-142°, the second field of view angle β can also be any one of 138°, 139°, 141° and 142° or other values between 138°-142°, specifically in This is not limited.

In some embodiments, in the second scanning mode, the size of the first field of view angle α of the laser scanning device 100 is between 7°-11°, and the size of the second field of view angle β is between 138°-142° between.

Specifically, in the second scanning mode, the size of the first field of view angle α is preferably 9°, and the size of the second field of view angle β is preferably 140°. Of course, in other embodiments, the size of the first field of view angle α is and the second angle of view β can also be other values, for example, the first angle of view α can be any one of 7°, 8°, 10° and 11° or other values between 7° and 11° , the second field of view angle β may be any one of 138°, 139°, 141°, and 142°, or other values between 138° and 142°, which are not specifically limited herein.

In the description of this specification, reference is made to the terms "some embodiments," "one embodiment," "some embodiments," "exemplary embodiments," "examples," "specific examples," or "some examples," etc. The description means that a particular feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms 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.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined as "first", "second" may expressly or implicitly include at least one of said features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Variations, modifications, substitutions, and alterations are made to the embodiments, and the scope of the present application is defined by the claims and their equivalents.

Claims

A laser scanning device, characterized in that the laser scanning device comprises a light source, a first light refraction element, and a second light refraction element or a light reflection element, and the light emitted by the light source passes through the first light refraction element in sequence , and the second light-refractive element or the light-reflecting element exits after the first light-refractive element and the second light-refractive element or the light-reflecting element can be rotated to change the exit angle of the light;

Wherein, the laser scanning device has a first scanning mode and a second scanning mode, and the field angle of the laser scanning device in the first scanning mode is different from that in the second scanning mode; and / or

The point cloud coverage uniformity of the laser scanning device in the first scan mode is different from the point cloud coverage uniformity in the second scan mode; and/or

The point cloud coverage integrity of the laser scanning device in the first scan mode is different from the point cloud coverage integrity in the second scan mode.
The laser scanning device according to claim 1, wherein the laser scanning device comprises the first light refraction element and the second light refraction element, and the first light refraction element comprises opposite and non-parallel light refraction elements. a first light incident surface and a first light exit surface, the second light refraction element includes a second light entrance surface and a second light exit surface that are opposite and not parallel, and the light emitted by the light source passes through the first light entrance surface in sequence , the first light-emitting surface and the second light-incident surface are emitted through the second light-emitting surface.
The laser scanning device according to claim 2, wherein the field of view of the laser scanning device in the first scanning mode is larger than the field of view in the second scanning mode;

The point cloud coverage uniformity of the laser scanning device in the first scanning mode is smaller than the point cloud coverage uniformity in the second scanning mode.
The laser scanning device according to claim 3, wherein the point cloud coverage integrity of the laser scanning device in the first scanning mode is greater than the point cloud coverage integrity in the second scanning mode.
The laser scanning device according to any one of claims 2-4, wherein, in the first scanning mode, the rotation speed of the first light refracting element is different from the rotation speed of the second light refracting element speed;

In the second scanning mode, the rotation speed of the first light refraction element is the same as the rotation speed of the second light refraction element, and the rotation direction of the first light refraction element is the same as the rotation direction of the second light refraction element The elements rotate in the opposite direction.
The laser scanning device according to claim 3, wherein the laser scanning device further has a third scanning mode, and the field angle of the laser scanning device in the third scanning mode is the same as that in the first scanning mode. The same field of view in scan mode;

The uniformity of point cloud coverage of the laser scanning device in the third scan mode is greater than that in the first scan mode, and smaller than the uniformity of point cloud coverage in the second scan mode Spend.
The laser scanning device according to claim 6, wherein the point cloud coverage integrity of the laser scanning device in the third scanning mode is the same as the point cloud coverage integrity in the first scanning mode and greater than the point cloud coverage completeness in the second scanning mode.
The laser scanning device according to claim 7, wherein in the third scanning mode, the rotational speed of the first light refraction element is the same as the rotational speed of the second light refraction element, and the The rotation direction of the first light refraction element is the same as the rotation direction of the second light refraction element.
The laser scanning device according to claim 6, wherein, in the third scanning mode, the laser scanning device repeatedly scans along a circular trajectory for a period of time corresponding to one frame of point cloud image.
The laser scanning device according to any one of claims 2-4, characterized in that, in the first scanning mode, the density of the central region of the scanning pattern in a frame of point cloud image of the laser scanning device is higher than The density of the peripheral region.
The laser scanning device according to any one of claims 2-4, characterized in that, in the second scanning mode, the laser scanning device repeatedly scans along one scanning track for a period of time corresponding to one frame of point cloud image Second-rate.
The laser scanning device according to claim 10, wherein in the first scanning mode, the laser scanning device scans along the scanning pattern only once in a period corresponding to one frame of point cloud image.
The laser scanning device according to claim 10, wherein the laser scanning device further has a third scanning mode, and the field angle of the laser scanning device in the third scanning mode is the same as that in the first scanning mode. The same field of view in scan mode;

The uniformity of point cloud coverage of the laser scanning device in the third scan mode is greater than that in the first scan mode, and smaller than the uniformity of point cloud coverage in the second scan mode Spend;

In the third scanning mode, the laser scanning device repeatedly scans along a scanning trajectory for a period of time corresponding to one frame of point cloud image, wherein the scanning trajectory in the first scanning mode is compared with the scanning trajectory in the first scanning mode. Scan trajectories in three-scan mode have a higher scan density in one of the directions.
The laser scanning device according to claim 1, wherein the laser scanning device comprises the first light refraction element and the light reflection element, and the first light refraction element comprises opposite and non-parallel first light refraction elements. A light incident surface and a first light emitting surface, the light reflecting element includes a reflective surface, after the light source emits light, the light passes through the first light incident surface and the first light emitting surface in sequence, then is emitted by the reflective surface and then exits.
The laser scanning device according to claim 14, wherein, in the first scanning mode, the rotation speed of the first light refraction element is greater than the rotation speed of the light reflection element;

In the second scanning mode, the rotational speed of the first light refracting element is the same as the rotational speed of the light reflecting element.
The laser scanning device according to claim 15, wherein the laser scanning device further has a third scanning mode, and in the third scanning mode, the rotation speed of the first light refracting element is lower than that of the light The rotational speed of the reflective element.
The laser scanning device according to claim 1, wherein in the first scanning mode, the scanning patterns of the laser scanning device in two adjacent frames of point cloud images are different.
The laser scanning device according to claim 1, wherein in the second scanning mode, the scanning patterns of the laser scanning device in two adjacent frames of point cloud images are the same.
The laser scanning device according to claim 1, wherein the laser scanning device is configured to switch the scanning mode based on a user's operation; or,

The laser scanning device is used to select a corresponding scanning mode according to the recognition of the scanning environment; or,

The laser scanning device is used for recommending a corresponding scanning mode to the user according to the recognition of the scanning environment, and determining the scanning mode based on the user's operation.
A laser scanning system, characterized in that it includes:

mobile platforms; and

The laser scanning device according to any one of claims 1-19, wherein the laser scanning device is mounted on the moving platform, and the moving platform is used to drive the laser scanning device to move to scan an object.
21. The laser scanning system of claim 20, wherein, in at least one of the scanning modes, the field of view angle comprises a first field of view angle in a forward direction of the moving platform and an angle of view along a direction perpendicular to the moving platform. A second field of view angle in the forward direction of the mobile platform, where the second field of view angle is greater than or equal to the first field of view angle.
The laser scanning system according to claim 21, wherein in the first scanning mode, the size of the first field of view of the laser scanning device is between 138° and 142°, and the The second field of view is between 138°-142°; and/or,

In the second scanning mode, the size of the first field of view of the laser scanning device is between 7°-11°, and the size of the second angle of view is between 138°-142° .