A laser emitting method, device, detection device and mobile platform

Abstract

The application discloses a laser emission method and device, a detection device and a mobile platform, and is applied to automatic driving or auxiliary driving. The laser emission device comprises a light beam generating device and an optical assembly. The light beam generating device is used for generating a first light beam and a second light beam. The first light beam is incident on the optical assembly and emitted from the optical assembly, the second light beam is incident on the optical assembly and emitted from the optical assembly, and a first light spot formed by the first light beam in space and a second light spot formed by the second light beam in space are separated in a horizontal direction. Since the two light spots emitted by the laser emission device are separated in the horizontal direction, the echoes of the two light spots are also separated in the horizontal direction, which helps to avoid the problem of symmetrical ghost images, thereby helping to provide the identification accuracy of the laser radar. It can be applied to the Internet of Vehicles, such as vehicle external connection V2X, inter-vehicle communication long term evolution technology LTE-V, vehicle-to-vehicle V2V and the like.

Description

[0001] This application is a divisional application. The original application has the application number 202110336412.2 and the original application date is March 29, 2021. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical detection technology, and in particular to a laser emission method, apparatus, detection device and mobile platform. Background Technology

[0003] LiDAR (Light Detection and Ranging) detects the position, shape, velocity, and other characteristics of target objects by emitting laser signals. Anchor-scanning LiDAR is currently the mainstream type, and common scanning methods include mechanical rotation scanning, polygon scanning, and optical phased array scanning.

[0004] Scanning lidar typically emits a linear beam of light in a scanning pattern to detect targets within a defined area. A scanning lidar system usually consists of a transmitting system, a scanning system, and a receiving system. However, due to reflections from components of the scanning system and the receiving system, a "ghost image" may appear on the detector of the receiving system, symmetrical about the detector's central axis of symmetry to the image of the normal target object. For example, in... Figure 1 In the scene shown, after the light spot is reflected by the target object, part of the light spot is normally received by the receiving system through the scanning system, and another part is projected onto the base of the scanning system. The light spot reflected by the base is then received by the receiving system through the scanning system. This part of the light spot reflected by the base is separated from the imaging area of ​​the normal light spot after being reflected by the receiving system, thus forming a symmetrical ghost image.

[0005] The presence of symmetrical ghost images will affect the identification of target objects by lidar. Therefore, in order to improve the accuracy of lidar identification, it is necessary to solve the problem of symmetrical ghost images during the imaging process. Summary of the Invention

[0006] This application provides a laser emission method, apparatus, detection device, and mobile platform, which can solve the problem of symmetrical ghost images in the process of lidar imaging.

[0007] In a first aspect, embodiments of this application provide a laser emitting device, including a beam generating device and an optical component; the beam generating device is used to generate a first beam and a second beam; the first beam is incident on and exits from the optical component, the second beam is incident on and exits from the optical component, and a first spot formed in space by the first beam and a second spot formed in space by the second beam are separated in the horizontal direction. Because the first beam and the second beam emitted by the laser emitting device are separated in the horizontal direction, the echoes of the two beams will also be separated in the horizontal direction. This ensures the detection viewing angle requirements in the vertical direction while avoiding the problem of symmetrical ghost images, thereby helping to improve the recognition accuracy of the lidar.

[0008] In one possible implementation, the first beam and the second beam belong to the same beam, that is, the first beam and the second beam are emitted simultaneously. A conventional lidar emits a single beam, and the field of view of this beam in the vertical direction is the lidar's field of view. In the embodiments of this application, the field of view formed by the first beam and the second beam in the vertical direction is the field of view of the laser emitting device. Since the first beam and the second beam are emitted simultaneously, they can be considered as the same beam. Because the simultaneously emitted first beam and second beam are separated in the horizontal direction, it helps to avoid the problem of symmetrical ghosting.

[0009] In one possible implementation, the beam generating device includes a first beam generating device and a second beam generating device; the first beam generating device includes a first laser source, which includes at least one laser, to generate the first beam; the second beam generating device includes a second laser source, which includes at least one laser, to generate the second beam. In this implementation, the first beam can be generated by at least one laser, and the second beam can also be generated by at least one laser, and the lasers used to generate the first beam and the second beam are different. In this case, the light intensity of the first beam and the second beam can be effectively guaranteed, and by using different lasers to generate the first beam and the second beam, it is not necessary to split the beams generated by the same laser using a beam splitter, which helps to reduce the complexity of the optical path design.

[0010] In one possible implementation, the optical components include a first collimating lens and a second collimating lens; the first beam is incident on the first collimating lens from a first position, the first position being located on the focal plane of the first collimating lens; the second beam is incident on the second collimating lens from a second position, the second position being located on the focal plane of the second collimating lens; the first position is located above or below the focal point of the first collimating lens, and / or, the position is located above or below the focal point of the second collimating lens. In this implementation, by utilizing the principle that the exit angle in the fast axis direction is different for beams incident on the collimating lens at different positions, the pointing angle of the first beam and / or the second beam in the horizontal direction is changed, thereby achieving the separation of the first beam and the second beam in the horizontal direction.

[0011] The first and second collimating lenses described above can collimate the light beam in the horizontal direction and adjust the beam's pointing angle in the horizontal direction. Optionally, the first and second collimating lenses can be fast-axis collimating lenses.

[0012] In one possible implementation, the optical component includes a reflecting prism, with the second beam incident from a right-angled side of the prism, and the second beam not perpendicular to the right-angled side. In this implementation, the principle that beams incident at different angles to the reflecting prism have different exit angles along the fast axis is utilized to change the horizontal pointing angle of the second beam, thereby achieving horizontal separation of the first and second beams.

[0013] In one possible implementation, the first optical component further includes a first wedge prism and a second wedge prism; the first and second wedge prisms are used to stitch the first beam and the second beam together in the vertical direction. Due to various limitations in optical path design, the generated first and second beams may have gaps in the vertical direction, or the field of view of the first and second beams may have been adjusted to their respective preset field of view, but due to excessive overlap, the field of view of the stitched first and second beams is smaller than the preset stitching field of view. The wedge prism can be used to adjust the exit angle of the beam in the vertical direction. The tilt angle of the wedge prism is designed according to the incident positions of the first and second beams, so that the formed first and second beam spots have no gaps in the vertical direction, avoiding the situation where some areas cannot be scanned when scanning the target object, or avoiding the inability to meet the required field of view due to excessive overlap.

[0014] In one possible implementation, the optical component further includes a homogenizer. The first beam is incident on and exits from the homogenizer, and the second beam is incident on and exits from the homogenizer. The light waves emitted by the laser have different intensities at different locations. The homogenizer makes the light intensity of the light waves approximately the same at different locations and helps to prevent the first and second light spots from exceeding a preset field of view in the vertical direction.

[0015] In one possible implementation, the stitching field of view of the first light spot and the second light spot in the vertical direction is 25 to 30 degrees.

[0016] In one possible implementation, the pointing angles of the first light spot and the second light spot in the horizontal direction differ by 0.3 to 0.6 degrees.

[0017] Secondly, embodiments of this application provide a detection device, which includes a laser emitting device as described in any implementation of the first aspect.

[0018] In one possible implementation, the detection device further includes a receiving device; the receiving device includes a detector, which includes a first effective region and a second effective region, respectively corresponding to the imaging regions of the echoes of the first light spot and the second light spot on the detector, and the first effective region and the second effective region are separated in the horizontal direction. The first effective region and the second effective region correspond to the echo imaging regions of the first beam and the second beam, respectively. Since the first beam and the second beam are separated in the horizontal direction, the corresponding first effective region and second effective region are also separated in the horizontal direction. This horizontal separation of the first effective region and the second effective region avoids the imaging region of symmetrical ghost images. Furthermore, identifying target objects based on the data collected from the first effective region and the second effective region helps improve the identification accuracy of the lidar.

[0019] Thirdly, embodiments of this application provide a mobile platform including the detection device as described in the second aspect and any implementation thereof.

[0020] Fourthly, embodiments of this application provide a laser emission method applied to a laser emission device, the laser emission device including a beam generating device and an optical component, the method including: the beam generating device generating a first beam and a second beam; the first beam incident on the optical component and exiting from the optical component, the second beam incident on the optical component and exiting from the optical component, and a first spot formed by the first beam in space and a second spot formed by the second beam in space being separated in the horizontal direction.

[0021] In one possible implementation, the first beam and the second beam belong to the same bundle.

[0022] In one possible implementation, the first beam and the second beam are generated by different lasers.

[0023] In one possible implementation, the optical component includes a first collimating lens and a second collimating lens; the first light beam incident on the optical component includes: the first light beam incident on the optical component from above or below the focal point of the first collimating lens; and / or, the second light beam incident on the optical component includes: the second light beam incident on the optical component from above or below the focal point of the second collimating lens.

[0024] Optionally, the first and second collimating lenses mentioned above can be fast-axis collimating lenses.

[0025] In one possible implementation, the optical component includes a reflecting prism; the second light beam incident on the optical component includes: the second light beam not being incident perpendicular to the right-angled side of the reflecting prism.

[0026] In one possible implementation, the optical component further includes a first wedge prism and a second wedge prism; the first light beam incident on the optical component includes: the first light beam incident on the first wedge prism; the second light beam incident on the optical component includes: the second light beam incident on the second wedge prism.

[0027] In one possible implementation, the optical component further includes a homogenizer.

[0028] In one possible implementation, the stitching field of view of the first light spot and the second light spot in the vertical direction is 25 to 30 degrees.

[0029] In one possible implementation, the pointing angles of the first light spot and the second light spot in the horizontal direction differ by 0.3 to 0.6 degrees. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of symmetrical ghost image imaging provided in an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the structure of the laser emitting device provided in the embodiments of this application;

[0032] Figure 3 A schematic diagram showing the separation of the first and second light spots in the horizontal direction, as provided in the embodiments of this application;

[0033] Figures 4(a) and 4(b) are schematic diagrams of the optical path of the fast-axis collimating lens provided in the embodiments of this application;

[0034] Figures 5(a) and 5(b) are schematic diagrams of the optical path of the reflecting prism provided in the embodiments of this application;

[0035] Figure 6 A schematic diagram illustrating the horizontal separation of the first and second light spots using a reflecting prism, provided as an embodiment of this application.

[0036] Figure 7 A schematic diagram of the vertical splicing of the first and second light spots provided in the embodiments of this application;

[0037] Figure 8 A schematic diagram of the field of view of the first and second light spots in the vertical direction provided in the embodiments of this application;

[0038] Figure 9 This is a schematic diagram of the light uniformity effect provided in the embodiments of this application;

[0039] Figure 10 This application provides a schematic diagram of the optical path of a specific embodiment.

[0040] Figure 11 This is a schematic diagram of the optical path of another specific embodiment provided in this application.

[0041] Figure 12 A schematic diagram of the first and second effective regions of the detector provided in the embodiments of this application;

[0042] Figure 13 This is a schematic diagram of the scanning spot provided in an embodiment of this application;

[0043] Figure 14 This is a schematic diagram of the mobile platform structure provided in an embodiment of this application;

[0044] Figure 15 This is a schematic diagram of a laser emission method provided in an embodiment of this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0046] This application provides a laser emitting device, a detection device, and a mobile platform to solve the problem of symmetrical ghost images during lidar imaging. The laser emitting device provided in this application can be applied to detection devices, such as lidar, to avoid the impact of symmetrical ghost images on target recognition.

[0047] The laser emitting device 20 provided in this application embodiment can be as follows: Figure 2 As shown, it includes a beam generating device 21 and an optical component 22.

[0048] Specifically, the beam generating device 21 generates a first beam and a second beam, both of which are incident on and exit from the optical component 22. The first beam exits the optical component 22 to form a first light spot in space, and the second beam exits the optical component to form a second light spot in space; the first and second light spots are separated in the horizontal direction. Specifically, the first and second light spots formed by the first and second beams can be configured as follows: Figure 3 As shown.

[0049] This application embodiment is particularly applicable to scanning lidar, where the first and second light spots can be line spots and are parallel to each other. Generally, the line spot used for scanning is a line spot in the vertical direction of spatial coordinates, and scanning is performed along the horizontal direction of spatial coordinates. Therefore, the horizontal direction in this application embodiment can be understood as the scanning direction, or it can also be understood as the direction perpendicular to the first and second light spots. For example, when taking the optical component 22 as a reference standard, the above-mentioned horizontal direction can also be understood as the fast axis direction of the optical component 22. It should be understood that the "horizontal direction" in this application embodiment is not limited to the horizontal direction of spatial coordinates. For example, if the first and second light spots are line spots in the horizontal direction of spatial coordinates, and scanning is performed along the vertical direction of spatial coordinates, then the first and second light spots can also be separated in the vertical direction of spatial coordinates.

[0050] Furthermore, the first and second beams mentioned above belong to the same beam; in other words, the laser emitting device 20 emits the first and second beams simultaneously. In a conventional scanning lidar, at a certain moment, a line spot is projected onto the target object, and the field of view of this spot in the vertical direction is the field of view of the lidar. At different times, by adjusting the emission angle of the line spot (i.e., the pointing angle of the spot in space), the position of the line spot projected onto the target object is changed, thereby achieving scanning of the target object. In this embodiment, a continuous line spot is replaced by two line spots. That is, the laser emitting device 20 can emit two spots simultaneously at the same time. The scanning of the target object is achieved by two horizontally separated spots, and the field of view formed by the first and second spots in the vertical direction is the field of view of the laser emitting device. Therefore, the first beam and the second beam can be regarded as the same beam. Simultaneously emitting two horizontally separated beams helps to avoid the problem of symmetrical ghosting.

[0051] In one possible implementation, the optical component 22 may include a first collimating lens 221 and a second collimating lens 222. The collimating lens serves to transform the generated light beam into a collimated beam, that is, to make the formed light spot closer to a straight line. In this embodiment, the first collimating lens 221 and the second collimating lens 222, in addition to collimating the emitted light spot, may also have the function of separating the formed first and second light spots in the horizontal direction. For example, the first collimating lens 221 and the second collimating lens 222 may be fast axis collimators (FAC).

[0052] Specifically, as shown in Figure 4(a), when the incident beam is located at the focal point of the fast-axis collimating lens and is parallel to the optical axis of the lens, the beam exiting the lens will be parallel to the principal optical axis in the horizontal direction. Based on Figure 4(a), when the fast-axis collimating lens is moved up and down, or the position of the incident beam is moved on the focal plane, the beam exiting the lens will no longer be parallel to the principal optical axis in the horizontal direction, as shown in Figure 4(b). In Figures 4(a) and 4(b), the horizontal direction is parallel to the plane of the paper, and the vertical direction is perpendicular to the plane of the paper.

[0053] Taking a fast-axis collimator as an example, the first collimator 221 and the second collimator 222 can be collimated by having the first light beam enter the first collimator 221 parallel to the principal optical axis from the focal position of the first collimator 221, and the second light beam enter the second collimator 222 parallel to the principal optical axis from above or below the focal point on the focal plane of the second collimator 222. Since the pointing angle of the first light beam in the horizontal direction does not change, but the pointing angle of the second light beam in the horizontal direction changes, the outgoing first light beam and the second light beam will be separated by a certain angle in the horizontal direction. The specific angle of separation is related to the incident position of the second light beam relative to the second collimator 222. Alternatively, the first beam can be incident on the first collimating lens 221 parallel to the principal optical axis from above or below the focal point on the focal plane of the first collimating lens 221, and the second beam can be incident on the second collimating lens 222 parallel to the principal optical axis from the focal point of the second collimating lens 222. This changes the horizontal pointing angle of the first beam while keeping the horizontal pointing angle of the second beam constant, thus achieving horizontal separation of the first and second light spots. Alternatively, the first beam can be incident on the first collimating lens 221 from above (or below) the focal point on the focal plane of the first collimating lens 221, and the second beam can be incident on the second collimating lens 222 from below (or above) the focal point on the focal plane of the second collimating lens 222. This changes the horizontal pointing angles of both the first and second beams, also achieving horizontal separation of the first and second light spots.

[0054] In another possible implementation, optical component 22 may also include a reflecting prism 223, through which the first and second light spots are separated in the horizontal direction. Specifically, as shown in Figure 5(a), if the light beam enters the reflecting prism along a direction perpendicular to the first right-angled side of the reflecting prism, its outgoing light beam will exit along a direction perpendicular to the second right-angled side of the reflecting prism. As shown in Figure 5(b), if the incident light beam is not perpendicular to the first right-angled side of the reflecting prism, its outgoing light beam is also not perpendicular to the second right-angled side of the reflecting prism.

[0055] exist Figure 6 In one specific embodiment shown, the first beam can be positioned parallel to the principal optical axis of the optical component without passing through the reflecting prism, while the second beam is positioned perpendicular to the principal optical axis. If the first right-angled side of the reflecting prism 223 is perpendicular to the second beam, then the second beam, after exiting the prism, will be parallel to the principal optical axis. And... Figure 6 Since the first right-angled side of the reflecting prism 223 is not perpendicular to the second beam, the beam emitted by the second beam after passing through the reflecting prism 223 is also not perpendicular to the second right-angled side of the reflecting prism 223. That is, the direction of the second beam in the horizontal direction after passing through the reflecting prism 223 is not parallel to the principal optical axis, thereby achieving separation from the first beam in the horizontal direction.

[0056] As shown in Figure 5(a), Figure 5(b) and Figure 6 As shown, a right-angled reflecting prism can change the propagation direction of a light beam. Therefore, in different designs, it can be determined whether the first light beam should also enter the reflecting prism to change its propagation direction, depending on the design requirements. Specifically, two reflecting prisms can be set up, with the first right-angled side of the first reflecting prism parallel to the principal optical axis of the optical component and the second right-angled side perpendicular to the principal optical axis. When the first light beam enters the first reflecting prism and is perpendicular to its first right-angled side, it exits perpendicular to the second right-angled side, meaning it exits parallel to the principal optical axis. Alternatively, the second light beam can be set perpendicular to the principal optical axis, but with the first right-angled side of the reflecting prism not parallel to the principal optical axis. This means the second light beam enters the second reflecting prism but is not perpendicular to its first right-angled side, resulting in the second light beam exiting in a direction that is also not perpendicular to its second right-angled side, meaning it exits not parallel to the principal optical axis. This horizontal direction separates the first and second light beams in the horizontal direction. Alternatively, two reflecting prisms can be set up, with the first beam not perpendicularly entering the first right-angled side of the first reflecting prism and the second beam not perpendicularly entering the second right-angled side of the second reflecting prism. This ensures that after the first beam passes through the first reflecting prism and the second beam passes through the second reflecting prism, the directions of the first beam and the second beam in the horizontal direction are not parallel to the principal optical axis of the optical component, thereby causing the emitted first beam and the second beam to separate in the horizontal direction.

[0057] In a polar coordinate system, if the laser emitting device 20 is taken as the origin, the pointing angles of the first and second light spots emitted from the laser emitting device 20 will differ. Optionally, the pointing angles of the first and second light spots in the horizontal direction can differ by 0.3 to 0.6 degrees. For example, if the first light spot is parallel to the principal optical axis, its pointing angle in the horizontal direction can be set to 0 degrees, and the pointing angle of the second light spot in the horizontal direction can be changed to -0.5 degrees through optical components, then the pointing angles of the first and second light spots in the horizontal direction will differ by 0.5 degrees. If the difference in pointing angles between the first and second light spots is too small, the imaging area of ​​the echoes from the first and second light spots will be close to the imaging area of ​​the ghost image, which is not conducive to avoiding the problem of symmetrical ghost images; if the difference in pointing angles between the first and second light spots is too large, it may have an adverse effect on subsequent data processing. Therefore, a reasonable pointing angle difference can be designed according to the distance between the laser emitting device 20 and the target object, the size of the target object, or other user requirements. Depending on different scenarios and requirements, the pointing angle difference between the first spot and the second spot in the horizontal direction can be greater than 0.6 degrees or smaller than 0.3 degrees. This application does not impose any restrictions.

[0058] In one possible design, the optical component 22 may further include a first wedge prism 224 and a second wedge prism 225, which are used to stitch the first light spot and the second light spot together in the vertical direction.

[0059] As mentioned above, the "vertical direction" in this application embodiment is the direction perpendicular to the "horizontal direction" in this application embodiment, and is not limited to the vertical direction in spatial coordinates. For example, if the first light spot and the second light spot are line light spots in the horizontal direction in spatial coordinates, and scanning is performed along the vertical direction, then the first light spot and the second light spot can also be separated in the vertical direction in spatial coordinates and spliced ​​together in the horizontal direction in spatial coordinates by a wedge prism.

[0060] In this embodiment, "splicing" refers to the absence of a gap between the first light spot and the second light spot in the vertical direction, allowing for an overlap between the first light spot and the second light spot in the vertical direction, such as... Figure 3 As shown; alternatively, the first and second light spots can be aligned precisely in the vertical direction, such as... Figure 7 As shown.

[0061] Due to various limitations in optical path design, such as the placement of various optical components and the size limitations of the overall laser emitting device, there may be a gap between the first and second beams in the vertical direction. Alternatively, even though the field of view angles of the first and second beams have been adjusted to their respective preset field of view angles, excessive overlap may result in a field of view angle smaller than the preset splicing field of view angle after the first and second beams are combined. In this case, a wedge prism can be used to adjust the vertical exit angle of the first and / or second beams, i.e., to translate the first and / or second beams in the vertical direction, thereby achieving the splicing of the first and second beams. The wedge prism has no effect on the horizontal pointing angle of the first and second beams. Specifically, the first wedge prism 224 can be used to adjust the exit angle of the first beam in the vertical direction, and the second wedge prism 225 can be used to adjust the exit angle of the second beam in the vertical direction. This ensures that the first and second light spots are seamless in the vertical direction, and prevents the first and second light spots from overlapping excessively, thus avoiding situations where the field of view fails to reach the preset field of view and preventing unscanned areas when scanning the target object. Alternatively, only one wedge prism can be used to adjust either the first or second beam to achieve the stitching of the first and second light spots.

[0062] In addition to wedge prisms, other devices capable of translating the beam can be used to adjust the beam in the vertical direction.

[0063] The widths of the first and second light spots in the vertical direction can be represented by the field of view angle in polar coordinates. For example... Figure 8As shown, if the laser emitting device 20 is taken as the origin of the polar coordinate system, and the first beam and the second beam are emitted from the origin, the field of view of the first spot in the vertical direction is θ degrees, and the field of view of the second spot in the vertical direction is -θ degrees. That is, the first spot can cover a field of view of 0 to θ degrees in space, and the second spot can cover a field of view of 0 to -θ degrees in space. Then, the field of view of the first spot and the second spot after being stitched together in the vertical direction is 2θ degrees. The above example takes the first spot and the second spot as having the same field of view and no overlap in the vertical direction. However, this application is not limited to this. The field of view of the first spot and the second spot can also be different, and the first spot and the second spot can also have an overlapping part in the vertical direction. Then, the field of view formed after the first spot and the second spot are stitched together is the sum of the field of view of the first spot and the field of view of the second spot minus the field of view of the overlapping part. In practical applications, the stitching field of view can be designed according to actual needs. For example, the stitching field of view of the first and second light spots in the vertical direction can be set to 25-30 degrees. Of course, depending on different scenarios and requirements, the stitching field of view of the first and second light spots in the vertical direction can also be greater than 30 degrees or less than 25 degrees, and this application does not impose any restrictions.

[0064] Optionally, the optical component 22 may further include a homogenizer, allowing both the first beam and the second beam to enter and exit the homogenizer. Due to the characteristics of light waves, the energy distribution of the generated beam may differ at different positions. The homogenizer can convert the beam into a light spot with a uniform energy distribution, meaning that the light intensity at different positions on the light spot is approximately equal, thereby avoiding the influence of uneven energy distribution of the light spot itself on the scanning results. In addition, the homogenizer can also control the first light spot and the second light spot within their respective preset field of view in the vertical direction. For example, if the preset field of view of the first light spot and the second light spot in the vertical direction is 14 degrees, the preset field of view after their stitching is 26 degrees. However, the field of view of the generated first beam and the second beam in the vertical direction may be greater than 14 degrees. The homogenizer can be used to make the field of view of the light spot formed by the first beam and the second beam in the vertical direction 14 degrees.

[0065] The aforementioned homogenizer may include a slow-axis collimator (SAC) and homogenizing optical elements. The first and second beams can be collimated by the slow-axis collimator before passing through the homogenizing element, which helps reduce the light intensity outside the preset field of view, such as... Figure 9 As shown. The homogenizing optical element can be a homogenizing microlens array or a homogenizing diffractive optical element (DOE).

[0066] When the optical assembly 22 includes a collimating lens (i.e., the first collimating lens 221 and the second collimating lens 222 in the aforementioned embodiment) and a homogenizer, the homogenizer can be placed after the collimating lens. Taking the example that the first and second light spots both have a preset field of view of 14 degrees in the vertical direction, if the first and second beams pass through the homogenizer before passing the collimating lens, their respective field of view will be adjusted to 14 degrees after passing through the homogenizer. However, after homogenization, the first and second beams then pass through the first collimating lens 221 and the second collimating lens 222 respectively, which may cause the first and second beams to be extended beyond the preset field of view. If the actual field of view of the first and second beams in the vertical direction exceeds the preset field of view, the imaging area of ​​the symmetrical ghost image may no longer be the expected imaging area. Therefore, when acquiring imaging data, the data of the symmetrical ghost image may still be read, which is detrimental to the identification of the target object.

[0067] In one possible implementation, the beam generating device 21 may include a first beam generating device and a second beam generating device. The first beam generating device includes a first laser source, which includes at least one laser for generating a first beam. The second beam generating device includes a second laser source, which includes at least one laser for generating a second beam. In this implementation, the first beam can be generated by at least one laser, and the second beam can also be generated by at least one laser. Furthermore, the lasers used to generate the first and second beams are different. In this case, the light intensity of the first and second beams can be effectively guaranteed. Using different lasers to generate the first and second beams eliminates the need to split beams generated by the same laser using a beam splitter, thus reducing the complexity of the optical path design.

[0068] Of course, only one laser source can be used, that is, the first laser source and the second laser source are the same laser source, and the beam generated by the one laser source is split into two beams by a beam splitter. In this implementation, since only one laser source is used, the laser source can be saved, that is, it is beneficial to reduce the cost of the laser emitting device.

[0069] In one specific embodiment, the optical path diagram of the laser emitting device 20 can be as follows: Figure 10 As shown, Figure 10The perspective is used to illustrate the optical path in the slow axis direction. Laser 1 generates a first beam 11, which enters the first collimating lens 221 from its focal point. After exiting, the first beam 11 remains unchanged in both the fast axis direction (perpendicular to the paper) and the slow axis direction (parallel to the paper). The exiting first beam 11 enters through homogenizer 226 and then enters the first wedge prism 224. The first beam 11 exiting the first wedge prism 224 is deflected on the slow axis. Laser 2 generates a second beam 22, which enters the second collimating lens. 222, but the second beam 22 is not located on the principal optical axis of the second collimating lens 222. After being emitted, the second beam 22 does not change in the slow axis direction, but is deflected in the fast axis direction (the direction perpendicular to the plane of the paper). The second beam 22 enters the homogenizer 226, and the light emitted from the homogenizer 226 enters the second wedge prism 225. The second beam 22 emitted from the second wedge prism 225 is deflected in the slow axis, so that the first light spot formed by the first beam 11 and the second light spot formed by the second beam 22 are separated in the fast axis direction, but there is no gap when they are joined in the slow axis direction.

[0070] exist Figure 10 In the specific embodiment shown, the first beam and the second beam first pass through the collimating lens, then through the homogenizer, and then through the wedge prism. It should be understood that the positional relationship of the collimating lens, homogenizer, and wedge prism is only an example, and the embodiments of this application are not limited thereto. The positional relationship of the three can also be adjusted according to design requirements. For example, the first beam and the second beam can pass through the collimating lens first, then through the wedge prism, and then through the homogenizer.

[0071] In another specific embodiment, the optical path diagram of the laser emitting device 20 can be as follows: Figure 11 As shown, Figure 11 The perspective shown is used to illustrate the optical path in the fast axis direction. Laser 1 generates a first beam 11, whose optical path is... Figure 10 Similar to the example shown, therefore Figure 11(Not shown). Laser 2 generates a second beam 22, which enters the second collimating lens 222 from its focal point. The exiting second beam 22 remains unchanged in both the fast axis direction (parallel to the paper) and the slow axis direction (perpendicular to the paper). After exiting, the second beam 22 enters the first right-angled side of the reflecting prism 223, but it is not perpendicular to this side, causing a shift in the fast axis direction. The second beam 22 enters the homogenizer 226, and the light emanating from it enters the second wedge prism 225. The exiting second beam 22 remains unchanged in the fast axis direction but shifts in the slow axis direction (perpendicular to the paper). The first spot formed by the first beam 11 and the second spot formed by the second beam 22 separate in the fast axis direction, but are joined seamlessly in the slow axis direction.

[0072] exist Figure 11 In the specific embodiment shown, the second beam passes through the collimating mirror, the reflecting prism, the homogenizer, and the wedge prism in sequence. It should be understood that the positional relationship of these four optical devices is only an example, and the embodiments of this application are not limited thereto. The positional relationship of each optical device can also be adjusted according to design requirements. For example, the second beam can pass through the reflecting prism, the collimating mirror, the wedge prism, and the homogenizer in sequence.

[0073] In the laser emitting device provided in the above embodiments of this application, since the two beams emitted by the laser emitting device are separated in the horizontal direction, the echoes of the corresponding two beams will also be separated in the horizontal direction, which helps to avoid the problem of symmetrical ghost images, thereby helping to improve the recognition accuracy of the lidar. Figure 13 As shown, when using this type of laser emitting device, although the first and second light spots are not projected onto the same straight line of the target object at the same time, the second light spot at time Ta and the first light spot at time Tb are located on the same straight line of the target object. The detection of this straight line position on the target object can be achieved through a later algorithm.

[0074] This application also provides a detection device, which may include the laser emitting device 20 described in any of the above implementations, to solve the problem of symmetrical ghost images and help improve the recognition accuracy of the detection device.

[0075] Furthermore, the aforementioned detection device may also include a receiving device. This receiving device includes a detector for acquiring echo data from a first light spot and a second light spot. The detector includes a first effective region and a second effective region, corresponding respectively to the imaging regions of the echoes from the first light spot and the second light spot. In conventional lidar receiving devices, the data reading area of ​​the detector can be as follows: Figure 1As shown, this is the imaging area of ​​the echo corresponding to a line spot. This imaging area is not separated in the horizontal direction. The imaging area of ​​symmetrical ghost images is within this data reading area. Therefore, if symmetrical ghost images are generated, their data will also be read and used for object detection and recognition, adversely affecting subsequent target object recognition. In this embodiment, the first effective area and the second effective area correspond to the imaging areas of the echoes of the first and second spots on the detector, respectively. Figure 12 As shown, since the first and second light spots are separated in the horizontal direction, their corresponding first and second effective regions are also separated in the horizontal direction. Because the first and second light spots together form the field of view of the laser emitter in the vertical direction, and there is only a small overlap between them, their corresponding first and second effective regions also together form the receiving area of ​​the laser emitter in the vertical direction. Since the first and second effective regions have only a small overlap in the vertical direction or just connect to non-overlapping areas, they avoid the imaging area of ​​symmetrical ghost images. By only reading data from the first and second effective regions, the problem of symmetrical ghost images can be avoided, thereby improving the accuracy of subsequent target object recognition.

[0076] like Figure 14 As shown in the illustration, this application also provides a mobile platform 30, including an information processing system 31 and the aforementioned detection device 32. The detection device 32 is used to determine information about the irradiated object. Specific implementations of the detection device 32 are described in the above embodiments, and repetitions will not be repeated. The information processing system 31 is used to determine the characteristic information of the irradiated object based on the reflected beam received by the detector in the detection device 32 and the emitted beam generated by the laser source. The characteristic information includes, but is not limited to, target distance, orientation, height, speed, attitude, and even shape. For example, the information processing system 31 can accurately measure the propagation time of the light pulse generated by the laser source from emission to reflection back to the detector from the irradiated object. Since the speed of light is known, the propagation time can be converted into a distance measurement, thereby determining the distance from the detection device 32 to the irradiated object.

[0077] In specific implementation, the information processing system 31 can be a hardware device of various forms, such as a processor, a microprocessor (e.g., a digital signal processor, DSP), an AI chip (e.g., a field programmable gate array, FPGA), or an application-specific integrated circuit (e.g., an ASIC).

[0078] Furthermore, if the laser source uses pulsed laser to continuously scan the irradiated object, it can obtain data on all target points on the irradiated object. After the information processing device in the receiving device performs imaging processing on this data, it can obtain an accurate three-dimensional image.

[0079] The mobile platform 30 also includes an electronic control system 311 coupled to the aforementioned information processing system 31. The electronic control system 311 includes a communication interface, which is used to communicate with the information processing system 31. The electronic control system 311 is used to control the motion state of the mobile platform 30 based on the characteristic information of the irradiated object.

[0080] Taking the aforementioned mobile platform 30 as an example of an autonomous vehicle, the autonomous vehicle includes the aforementioned detection device 32, information processing system 31, and electronic control system 311. The electronic control system 311 can be an electronic control unit (ECU), i.e., an onboard computer. When the detection device 32 identifies an obstacle ahead and the information processing system 31 calculates the obstacle's characteristic information, the electronic control system 311 can control the autonomous vehicle's drive unit to decelerate, stop, or turn around based on the obstacle's characteristic information and navigation information (such as a map). Alternatively, when the detection device 32 and the information processing system 31 determine that there is no obstacle, the electronic control system 311 can control the autonomous vehicle's drive unit to drive at a constant speed or accelerate based on the obstacle-free information.

[0081] In optional embodiments, the specific type of the mobile platform 30 is not limited. For example, it can be a mobile platform such as a car, ship, airplane, train, spacecraft, or drone, all of which are applicable to the technical solution of this application.

[0082] In addition, the mobile platform 30 may also include a global positioning system (GPS) device and an inertial measurement unit (IMU) device. The detection device 32 and the information processing system 31 can combine the measurement data from the GPS device and the IMU device to obtain characteristic information such as the position and velocity of the illuminated object. For example, the information processing system 31 can obtain the geographical location information of the mobile platform 30 through the GPS device and record the attitude and turning information of the mobile platform through the IMU device. After determining the distance between the detector 32 and the illuminated object based on the emitted and reflected beams of the detector 32, the measurement point of the illuminated object can be converted from a relative coordinate system to a position point in an absolute coordinate system using at least one of the geographical location information provided by the GPS device or the attitude and turning information provided by the IMU device, thereby obtaining the geographical location information of the illuminated object. Thus, the detection device 32 can be applied to the mobile platform.

[0083] This application also provides a laser emission method, which can be applied to a laser emission device, the laser emission device including a beam generating device and optical components. For example... Figure 15 As shown, the laser emission method may include the following steps:

[0084] Step 1501: The beam generating device generates a first beam and a second beam.

[0085] Step 1502: A first light beam enters the optical component and exits from the optical component, a second light beam enters the optical component and exits from the optical component, and the first light spot formed by the first light beam in space and the second light spot formed by the second light beam in space are separated in the horizontal direction.

[0086] In one possible implementation, the first beam and the second beam belong to the same bundle.

[0087] In one possible implementation, the first beam and the second beam are generated by different lasers.

[0088] In one possible implementation, the optical component includes a first collimating lens and a second collimating lens; the first light beam incident on the optical component includes: the first light beam incident on the optical component from above or below the focal point of the first collimating lens; and / or, the second light beam incident on the optical component includes: the second light beam incident on the optical component from above or below the focal point of the second collimating lens.

[0089] Optionally, the first and second collimating lenses mentioned above can be fast-axis collimating lenses.

[0090] In one possible implementation, the optical component includes a reflecting prism; the second light beam incident on the optical component includes: the second light beam not being incident perpendicular to the right-angled side of the reflecting prism.

[0091] In one possible implementation, the optical component further includes a first wedge prism and a second wedge prism; the first light beam incident on the optical component includes: the first light beam incident on the first wedge prism; the second light beam incident on the optical component includes: the second light beam incident on the second wedge prism.

[0092] In one possible implementation, the optical component further includes a homogenizer.

[0093] In one possible implementation, the stitching field of view of the first light spot and the second light spot in the vertical direction is 25 to 30 degrees.

[0094] In one possible implementation, the pointing angles of the first light spot and the second light spot in the horizontal direction differ by 0.3 to 0.6 degrees.

[0095] Furthermore, it should be understood that in the description of this application, terms such as "first," "second," and "third" are used only for distinguishing purposes and should not be construed as indicating or implying relative importance or order. References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in still other embodiments" appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0096] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions conceived by those skilled in the art based on the technical solution disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A laser emitting device, characterized by, The laser emitting device comprises: a light beam generating device and an optical assembly; the light beam generating device is configured to generate a first light beam and a second light beam; the first light beam is incident on and emergent from the optical assembly, the second light beam is incident on and emergent from the optical assembly, and a first spot formed by the first light beam in space and a second spot formed by the second light beam in space are separated in a fast axis, wherein the first light beam and the second light beam are linear spots parallel to each other.

2. The laser emitting device according to claim 1, wherein the optical assembly comprises a first collimating mirror and a second collimating mirror; the first light beam is incident on the first collimating mirror from a first position, the first position being located on a focal plane of the first collimating mirror; the second light beam is incident on the second collimating mirror from a second position, the second position being located on a focal plane of the second collimating mirror.

3. The laser emitting device according to claim 2, wherein the first collimating mirror and the second collimating mirror are fast axis collimating mirrors.

4. The laser emitting device according to claim 2 or 3, wherein the first position is located on a focal point of the first collimating mirror; and the second position is located on a focal point of the second collimating mirror.

5. The laser emitting device according to claim 4, wherein the optical assembly further comprises a reflective prism, the second light beam is incident on a straight angle side of the reflective prism, and the second light beam is not perpendicular to the straight angle side. the first position is located above or below the focal point of the first collimating mirror, and / or the second position is located above or below the focal point of the second collimating mirror.

6. The laser emitting device according to claim 2 or 3, wherein 7. The laser emitting device according to any one of claims 2-3, wherein the optical assembly further comprises a wedge prism, the wedge prism is configured to splice the first light beam and / or the second light beam in a slow axis direction. the optical assembly further comprises a homogenizer.

8. The laser emitting device of any one of claims 2-3, wherein, the light beam generating device comprises a first light beam generating device and a second light beam generating device; 9. The laser emitting device according to any one of claims 1-3, wherein, the first light beam generating device comprises a first laser light source, the first laser light source comprises at least one laser, and the first laser light source is configured to generate the first light beam; the second light beam generating device comprises a second laser light source, the second laser light source comprises at least one laser, and the second laser light source is configured to generate the second light beam. the first light beam and the second light beam belong to the same linear beam.

10. The laser emitting device of any one of claims 1-3, wherein, a splicing field of view angle of the first spot and the second spot in a vertical direction is 25-30 degrees.

11. The laser emitting device of any one of claims 1-3, wherein, the detection device comprises the laser emitting device according to any one of claims 1-11.

12. A detection device, characterized in that the detection device further comprises a receiving device; 13. The probe device of claim 12, wherein, the receiving device comprises a detector, the detector comprises a first active area and a second active area, the first active area and the second active area correspond to imaging areas of echoes of the first spot and the second spot on the detector respectively, and the first active area and the second active area are separated in a horizontal direction. the detection device comprises the laser emitting device according to claim 13.

14. A mobile platform, comprising: ​

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