2d scanning high precision lidar using a combination of a rotating concave mirror and a beam steering device

Abstract

The present disclosure relates to a 2D scanning high precision LiDAR using a combination of a rotating concave mirror and a beam-steering device. The system includes a first light source configured to provide first light pulses. The system also includes one or more beam-steering devices optically coupled to the first light source. Each beam-steering device includes a rotatable concave reflector and a beam-steering device disposed at least partially within the rotatable concave reflector. The combination of the beam-steering device and the rotatable concave reflector, as they move relative to each other: steer the one or more first light pulses both vertically and horizontally to illuminate an object within a field of view; obtain one or more first return light pulses, the one or more first return light pulses being generated based on the steered first light pulses illuminating the object within the field of view; and redirect the one or more first return light pulses.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on December 20, 2017, with application number 2017800032023 and invention title "High-precision 2D scanning LiDAR using a combination of a rotating concave mirror and a beam steering device". Technical Field

[0002] This disclosure relates generally to light detection and ranging (LiDAR), and more specifically to a system for scanning a series of light pulses to illuminate an object in a field of view and coaxially collecting scattered light from each light pulse for ranging of the object in the field of view. Background Technology

[0003] To reduce the size of LiDAR systems, efforts are being made to implement on-chip microelectromechanical systems (MEMS) to direct light pulses to illuminate objects in the field of view. This on-chip solution reduces the size of LiDAR systems. However, these on-chip MEMS designs typically produce optical aperture cross-sections of a few millimeters (less than 5 mm) or smaller, making it difficult to distinguish light pulses reflected from objects at greater distances (e.g., 100 meters) from background noise. It has been found that larger optical aperture cross-sections improve the signal-to-noise ratio of light. However, due to their system configuration, typical LiDAR systems can be bulky and expensive. These systems may not be easily integrated into vehicles and / or may be prohibitively expensive to integrate with them. Therefore, a high-precision LiDAR system with reduced size and cost is desired. Some challenges facing high-precision LiDAR systems include reducing the size of the LiDAR system while increasing the cross-sectional area of ​​the collecting optical aperture. Summary of the Invention

[0004] The following provides a brief overview of one or more examples to offer a basic understanding of this disclosure. This invention is not intended as a comprehensive summary of all anticipated examples, nor is it intended to identify key or defining elements of all examples or to define the scope of any or all examples. Its purpose is to present some concepts of one or more examples in a simplified form as a prelude to the more detailed description that follows.

[0005] According to some embodiments, a LiDAR (Light Detection and Ranging) scanning system is provided. The system includes a first light source configured to provide one or more first light pulses. The system also includes one or more beam steering devices optically coupled to the first light source. Each beam steering device includes a rotatable concave reflector and a beam steering mechanism positioned such that the light pulse guided by the rotatable concave reflector or beam steering mechanism can be further directed in different directions by the beam steering mechanism or rotatable concave reflector. When the beam steering mechanism and the rotatable concave reflector move relative to each other, the combination of the two deflects the one or more first light pulses in both the vertical and horizontal directions to illuminate an object within the field of view; obtains one or more first return light pulses generated based on the deflected first light pulses illuminating the object within the field of view; and redirects the one or more first return light pulses to one or more return light detectors. Attached Figure Description

[0006] To better understand the various aspects described, reference should be made to the following description in conjunction with the accompanying drawings, in which similar reference numerals refer to the corresponding parts throughout the drawings.

[0007] Figure 1A Multiple coaxial LiDAR systems attached to the vehicle are shown.

[0008] Figure 1B An exemplary beam deflector having a polyhedron located within a concave reflector is shown.

[0009] Figure 1C An exemplary beam steering device with a wobbling mirror instead of a concave reflector is shown.

[0010] Figure 2A A dual-eye LiDAR system is shown.

[0011] Figure 2B A coaxial LiDAR system with a converging lens is shown.

[0012] Figure 2C A coaxial LiDAR system with a converging mirror is shown.

[0013] Figure 3 A dual coaxial LiDAR system is shown.

[0014] Figure 4A An exemplary beam steering device is shown that directs emitted light to a direction between the positive x-axis and the positive z-axis and collects scattered light from that direction.

[0015] Figure 4BAn exemplary beam steering device is shown that directs emitted light to a direction between the negative x-axis and the positive z-axis and collects scattered light from that direction.

[0016] Figure 5 An exemplary beam deflector is shown that directs emitted light toward the edge of the positive horizontal range of the field of view and collects scattered light from that direction.

[0017] Figure 6A and Figure 6B Interlaced frames of the angular distribution of the dual coaxial LiDAR system in the horizontal and vertical directions are shown.

[0018] Figure 7 A thermal map corresponding to the width of the collection aperture is shown along the xz plane at y=0 in the horizontal and vertical directions of the dual coaxial LiDAR system.

[0019] Figure 8 An exemplary process for LiDAR scanning detection is shown.

[0020] Figures 9A to 9D A different view of another embodiment of the beam steering device according to the example of this disclosure is shown.

[0021] Figures 10A to 10B Various exemplary configurations for generating collimated laser beams are shown according to examples of this disclosure.

[0022] Figure 11 An exemplary configuration of a beam steering device for increasing the receiving aperture and for collecting returned light pulses from different facets, according to an example of this disclosure, is shown.

[0023] Figures 12A to 12C An exemplary configuration of a receiving optical system according to an example of this disclosure is shown.

[0024] Figures 13A to 13B An exemplary detector element for light collection using a photosensitive device is shown according to an example of this disclosure.

[0025] Figures 14A to 14B An exemplary configuration for combining optical pulses from different facets using a combination of free-space optics or fiber bundles and / or power combiners, according to an example of this disclosure, is shown.

[0026] Figures 15A to 15E Various configurations of multiple facets of an exemplary polyhedron having curved and flat surfaces are shown according to examples of this disclosure.

[0027] Figure 16An exemplary configuration of a LiDAR system for determining the time of flight of a light pulse, according to an example of this disclosure, is shown.

[0028] Figure 17 A reference pulse and a received return optical pulse are shown as examples according to this disclosure.

[0029] Figure 18 Another embodiment of a beam steering device with a swaying mirror according to an example of this disclosure is shown.

[0030] Figure 19 An exemplary flowchart of a method for determining the time of flight of one or more laser pulses, according to an example of this disclosure, is shown. Detailed Implementation

[0031] The detailed description below, taken in conjunction with the accompanying drawings, is intended as a description of various configurations and is not intended to represent the only configuration in which the concepts described herein can be practiced. This detailed description includes specific details used to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid confusion with these concepts.

[0032] Examples of LiDAR scanning systems will now be presented using various elements of the reference apparatus and methods. These apparatuses and methods will be described and illustrated below in detail and with accompanying drawings by various boxes, components, circuits, steps, processes, algorithms, etc. (collectively, “elements”). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the system as a whole.

[0033] This disclosure describes a high-precision 2D scanning LiDAR system using a combination of a rotatable concave reflector and a beam steering device. The LiDAR system includes a beam steering device with a polyhedral reflector located within a concave reflector aligned about a central axis. The concave reflector is configured to rotate about the central axis. The polyhedron is configured to pivot about a pivot along a direction at an angle (e.g., 90 degrees) to the central axis. The corresponding instantaneous positions of the concave reflector and the polyhedron deflect light pulses to illuminate objects in the field of view, while simultaneously collecting scattered light from the light pulses scattered on the objects. Each emitted light pulse is substantially coaxial or parallel to the collected scattered light from the corresponding light pulse. The LiDAR system includes a microcontroller for calculating the distance to the object based on the time difference between each emitted light pulse and the collected light from the corresponding light pulse scattered on the object. This disclosure also describes interleaved subframes for achieving higher resolution frames. This technique involves sampling range points of one or more objects in consecutive horizontal and vertical directions to form one or more subframes. The vertical and / or horizontal positions of sample points in consecutively captured subframes are slightly offset, and when these positions are combined, they provide an interlaced, higher density of sample points. The higher the sample point density, the higher the resolution of the LiDAR system.

[0034] Although the examples described in this disclosure are for integration in vehicles, other applications are also possible. For example, centralized laser transmission systems and multiple LiDAR systems can be installed in or integrated with robots, installed in multiple locations in buildings for security monitoring purposes, or installed at traffic intersections or certain road locations for traffic monitoring, etc.

[0035] Figure 1A Multiple LiDAR scanning systems 300A to 300F attached to vehicle 150 are shown. LiDAR scanning systems 300A to 300F can be 2D scanning LiDAR systems. Each LiDAR scanning system 300A to 300F detects and calculates the range of objects within its field of view corresponding to locations at and around vehicle 150. As an example, a LiDAR scanning system 300A positioned at the front of vehicle 150 illuminates adjacent vehicles 150' (and / or other objects) with light pulses collected substantially coaxially or parallel to each corresponding light pulse. The range (e.g., distance) to adjacent vehicles 150' is determined based on the time difference of each light pulse emission, and scattered light from the corresponding light pulse is detected.

[0036] like Figure 1AIn the depicted example, multiple LiDAR scanning systems 300A to 300F are distributed around vehicle 150 to cover the field of view between each individual coaxial LiDAR system. For example, the field of view may be configured such that LiDAR scanning system 300F can detect the centerline 154 on one side of vehicle 150, and LiDAR scanning system 300C can detect the lane divider line 152 on the other side of vehicle 150. In some cases, the field of view of one or more of the multiple LiDAR scanning systems 300A to 300F may overlap. For example, the field of view of LiDAR scanning system 300B may overlap with the field of view of LiDAR scanning system 300A. Overlapping field of view provides a higher sampling density. Similarly, the field of view of LiDAR scanning system 300A may overlap with the field of view of LiDAR scanning system 300F. Each LiDAR scanning system 300A to 300F may include a beam steering device that can vertically and horizontally deflect light pulses to emit them into the field of view for scanning objects. The redirection of the light pulses enables continuous point sampling from one or more objects within the field of view.

[0037] It should be understood that Figure 1A The size of the LiDAR scanning systems 300A to 300F depicted can be relatively small. That is, each corresponding LiDAR scanning system (e.g., system 300A to 300F) can occupy, for example, no more than 1 cubic foot or 1 / 4 cubic foot of space.

[0038] Figure 1B An exemplary beam steering device 100 is shown, having a beam steering mechanism (e.g., polyhedron 102) disposed within a concave reflector 112. Figure 1B As depicted, in some embodiments, the concave reflector 112 is coaxially aligned (e.g., substantially concentric) with the first axis 106. The concave reflector 112 may include one or more reflective surfaces (e.g., plane mirrors) located on the concave side surrounding the aperture 118. The aperture 118 of the concave reflector 112 is coaxially aligned (e.g., substantially concentric) with the first axis 106. Figure 1B In the depicted example, the mirror is angled inward to form a hexagonal bowl for the concave reflector 112. Figure 1BIn the depicted example, the hexagonal aperture 118 of the concave reflector 112 may have a width of one inch on opposite sides of the (e.g., hexagonal) aperture 118, and the reflective surface (e.g., a mirror) of the concave reflector 112 may form a 45° angle (along an angled mirror) with the 2.45-inch long hexagonal aperture 118. In some embodiments, the reflective surface (e.g., a mirror) of the concave reflector 112 ranges from 0.2 inches to 4 inches. In some embodiments, the reflective surface of the concave reflector 112 may be curved. In some examples, the curved surface protrudes outward (e.g., convex), which can be used to increase the field of view of the beam steering device 100. In some examples, the curved surface protrudes inward (e.g., concave).

[0039] like Figure 1B As depicted, a polyhedron 102 may be disposed within a concave reflector 112. The polyhedron 102 includes a pivot 120 coaxially aligned (e.g., substantially concentric) with a second axis 104 perpendicular to the first axis 106. The polyhedron 102 also includes at least one reflective surface (e.g., a mirror) disposed at a facet of the polyhedron 102 to redirect light between the aperture 118 of the concave reflector 112 and at least one reflective surface (e.g., a mirror) of the concave reflector 112. For example, a light pulse emitted through the aperture 118 toward the reflective surface of the polyhedron 102 can be redirected or redirected toward the reflective surface of the concave reflector 112, and the light pulse can be further redirected or redirected into the field of view. Figure 1B In the depicted example, polyhedron 102 is a cube with six faces. In some examples, two opposing faces with pivot 120 do not have reflective surfaces (e.g., mirrors), while the remaining four faces have outward-facing reflective surfaces (e.g., mirrors). Figure 1B In the example depicted, the cube has an edge length of approximately 1.22 inches.

[0040] It should be understood that the polyhedron 102 may have six facets that are not perfectly orthogonal. For example, in some embodiments, the polyhedron 102 may have asymmetrical facets that can offset and / or alter the interlaced grating pattern between subframes in terms of vertical and horizontal scanning directions. In some examples, the polyhedron 102 is a rhombohedron. It should also be understood that the polyhedron 102 may have fewer than six facets. For example, in some embodiments, the polyhedron 102 is a pentahedron. In such an embodiment, the polyhedron 102 may be a triangular prism, with the pivot located at two opposing triangular facets and one or more reflective surfaces (e.g., mirrors) located at rectangular facets. It should also be understood that the polyhedron 102 may have more than six facets. For example, the polyhedron 102 may be a hexahedron, heptahedron, octahedron, etc. In some embodiments, the facets of the polyhedron 102 are curved. In some examples, the curved facets project outwards (e.g., convex), which can be used to increase the field of view of the beam steering device 100. In some examples, the curved facets protrude inward (e.g., concave), which can reduce the field of view and shape the profile of the emitted laser beam.

[0041] In some embodiments, the beam steering device 100 includes one or more motors (not shown) operably coupled to the concave reflector 112 and the polyhedron 102. In this example, the one or more motors may be configured to rotate the concave reflector 112 counterclockwise (when viewed along the -z direction) about a first axis 106 at a first rotational speed 116, such as... Figure 1B As depicted. One or more motors may also be configured to rotate the polyhedron 102 about a pivot 120, which rotates about a second axis 104 in a counterclockwise direction (when viewed along the +y direction) at a second rotational speed 114. In some embodiments, a rotation controller is configured to control a first rotational speed 116 of the concave reflector 112 and a second rotational speed 114 of the polyhedron 102. In some cases, the rotation controller is electrically coupled to one or more motors to independently control the first rotational speed 116 of the concave reflector 112 and the second rotational speed 114 of the polyhedron 102. In some embodiments, the first rotational speed 116 of the concave reflector 112 is different from the second rotational speed 114 of the polyhedron 102. For example, the second rotational speed 114 of the polyhedron 102 may be faster than the first rotational speed 116 of the concave reflector 112. Figure 1B In the depicted example, the second rotational speed 114 of the polyhedron 102 can be set to 500 revolutions per second (rps), while the first rotational speed 116 of the concave reflector 112 can be set to 10 rps. In some embodiments, the second rotational speed 114 of the polyhedron 102 can be slower than the first rotational speed 116 of the concave reflector 112.

[0042] In some implementations, for each sampling point in a scan enabled by the beam steering device 100, the instantaneous position of the rotating polyhedron 102 relative to the rotating concave reflector 112 allows the beam steering device 100 to guide or deflect the light pulse toward the object and collect the returning light pulse from the object along a substantially similar optical path. Reference Figure 1B The instantaneous position of the rotating polyhedron 102 can be measured relative to the positive z-axis. When measured counterclockwise (e.g., along the y-axis), the angle of the polyhedron 102 is positive. The instantaneous position of the rotating concave reflector 112 can be measured relative to the negative y-axis. When measured clockwise (e.g., along the z-axis), the angle of the concave reflector 112 is positive.

[0043] It should be understood that other mechanisms that provide the same effect as the rotating concave reflector 112 and / or the rotating polyhedron 102 can be applied. For example, such as Figure 1C As depicted, the concave reflector 112 can be replaced by a oscillating mirror 112A that oscillates along axis 129. Thus, the rotation of the polyhedron 102 coupled to the oscillating mirror 112A can provide a similar steering mechanism for scanning continuous light pulses to illuminate objects in the field of view and for collecting return light from each light pulse coaxial with or parallel to the illuminating light pulses to range the objects in the field of view. In another example, the polyhedron 102 can be driven by an actuator that oscillates the polyhedron back and forth along an axis. In some examples, the oscillating mirror 112A can oscillate about a first axis, and the polyhedron 102 can be positioned adjacent to the oscillating mirror 112A, such as... Figure 1C As shown. Polyhedron 102 may include a pivot coaxially aligned with a second axis. The second axis may be positioned at an angle (e.g., 90 degrees or 75 degrees) to the first axis. At least one mirror may be positioned at a facet of polyhedron 102 for reflecting light pulses between the aperture and the concave reflector 112. One or more motors or actuators are operatively coupled to the oscillating mirror 112A and polyhedron 102. One or more motors or actuators may be configured to cause the oscillating mirror 112A to rotate (as shown in 128A) or oscillate (as shown in 128B) about the first axis at a first frequency and to cause the rotatable polyhedron to rotate (as shown in 125A) or oscillate (as shown in 125B) about the second axis at a second frequency.

[0044] exist Figure 1BIn the depicted example, a light pulse 307A obtained from a light source is guided through aperture 118 toward polyhedron 102, which generates a redirected light pulse 307B by redirecting or reflecting the light pulse 307A. The light pulse 307B is guided toward a mirror on a concave reflector 112. The concave reflector 112 then generates a redirected light pulse 312A by redirecting or reflecting the redirected light pulse 307B. The redirected light pulse 312A is guided toward the field of view to illuminate an object within the field of view. The redirected light pulse 312A illuminates the object, which scatters the light pulses along one or more directions. Some pulses of the scattered light return to the beam steering device 100 as a first returned light pulse 207A. Figure 1B As shown, in some examples, the first returning light pulse 207A can return to the beam steering device 100 along an optical path substantially similar (coaxially) to that of the steering light pulse 312A. Each of the first returning light pulses 207A can be redirected or reflected by the concave reflector 112 to generate a redirected returning light pulse 209. The redirected returning light pulse 209 is directed toward the polyhedron 102, which then redirects and reflects the light pulse to generate a redirected returning light pulse 214A. The redirected returning light pulse 214A is directed to the return light detector through the aperture 118.

[0045] Figure 2A A binocular LiDAR system 200 is illustrated. In some examples, the binocular LiDAR system 200 emits light pulses generated from a light source along an illumination optical path 210C, passing through a first aperture 210A to reach an object within the field of view. The emitted light pulses reach the object and are scattered and dispersed in one or more directions. Some of the scattered light pulses travel along a detection optical path 210D, passing through a second aperture 210B, and return to the photodetector. The geometry of the binocular LiDAR system 200 determines the detection range, which is determined by... Figure 2A The overlapping region between the exemplary illumination optical path 210C and the detection optical path 210D is defined. Thus, scattered light pulses in certain regions along the optical path of the binocular LiDAR system 200 may not return through the second aperture 210B. In some embodiments, the illumination optical path 210C and the detection optical path 210D are substantially parallel (e.g., at a small angle). Therefore, the detection range can be wide. For example, as... Figure 2A The depicted detection range may not have a boundary on the right side. The advantage of a binocular LiDAR system is that the illumination optics and detection optics are physically separated within the LiDAR scanning system, thus making it easier to avoid light interference in the detection module through light scattering in the illumination optics.

[0046] Figure 2BA coaxial LiDAR scanning system 250 with a converging lens 224 is shown. In some embodiments, the coaxial LiDAR scanning system 250 includes a light source 220, a mirror 222, a converging lens 224, a shield 226 with an aperture, a photodetector 230, and a beam steering device 100. Figure 2B As depicted, an incident light pulse 212A generated from light source 220 is guided to reflector 222, which reorients or reflects the incident light pulse 212A to generate a reoriented light pulse 212B. The reoriented light pulse 212B is guided along optical axis 211 to beam steering device 100. Beam steering device 100 can then steer the reoriented light pulse 212B as described above to generate a steerable light pulse 212C for illuminating objects in the field of view (FOV), wherein... Figure 2B The orientation of 212C is only shown at the time point when the turning direction is parallel to the orientation of 212B. At other times, the orientation of 212C can be in other directions within the FOV. Figure 2B In the depicted example, mirror 222 may be a near 100% reflector positioned at optical axis 211, which runs along the optical paths of both the redirected optical pulse 212B and the redirected return optical pulse 214. It should be understood that mirror 222 should be small enough not to block or interfere with the redirected return optical pulse 214.

[0047] exist Figure 2B In the example, the beam steering device 100 can be from Figure 1B A coaxial beam steering device 100 is provided. In some examples, the beam steering device 100 may be a bicoaxial device that realizes two substantially parallel light pulses directed towards one or more objects in the field of view. The beam steering device 100 may be configured to redirect the redirected light pulse 212B in both the vertical and horizontal directions to generate a redirected light pulse 212C, while collecting a return light pulse 212D along a substantially identical optical path to the redirected light pulse 212C. The beam steering device 100 redirects the return light pulse 212D to generate a redirected return light pulse 214 in the opposite direction to 212B. In this way, the optical path from the return light pulse 212D to the redirected return light pulse 214 overlaps with the illumination optical path of the redirected light pulse 212B to redirect the light pulse 212C, thereby increasing the effective detection range.

[0048] refer to Figure 2B In the coaxial LiDAR scanning system 250, the converging lens 224 is configured to collect the redirected return light pulses 214 along the optical axis 211 and guide the redirected return light pulses 214 through the aperture of the shield 226 to the photodetector 230. The converging lens 224 can be made of any transparent material (such as high-refractive-index glass, plastic, etc.). Figure 2B As depicted, the converging lens 224 can be substantially concentric with the optical axis 211. It should be understood that in some embodiments, the converging lens 224 is configured to be non-concentric with the optical axis 210.

[0049] like Figure 2B As depicted, in some examples, the photodetector 230 is configured to be substantially concentric with the optical axis 211. The photodetector 230 may be a photodiode, an avalanche photodiode, etc. In some implementations, such as Figure 2B As shown in the enlarged view of the depicted photodetector 230, the photodetector 230 may include a reflective surface 231 (e.g., a mirror) on the opposite side facing the light incident surface 232. The reflective surface 231 can redirect (e.g., reflect) light back to the absorption region of the photodetector 230, thereby improving detection efficiency and sensitivity. In some embodiments, a mask 226 may be part of the photodetector 230. Generally, the mask 226 filters redirected return light pulses 214 that are tilted at an angle relative to the optical path (e.g., along the optical axis 211) near the photodetector 230, such that only light pulses substantially parallel to the optical axis 211 can reach the photodetector 230.

[0050] exist Figure 2B In the illustrated examples, light source 220 may be a laser source. In some examples, the laser generated by light source 220 may have wavelengths in the visible spectrum. In some examples, the laser may have wavelengths in the infrared spectrum. In some examples, the laser may have wavelengths in the ultraviolet spectrum.

[0051] Figure 2C A coaxial LiDAR scanning system 250' with a converging lens 221 is shown. In some embodiments, the coaxial LiDAR scanning system 250' includes a light source 220, a converging lens 221, a shield 226 with an aperture, a photosensor 230, and a beam steering device 100. Figure 2CAs depicted, an incident light pulse 212A generated from light source 220 is guided along optical axis 211 through an aperture of converging mirror 221 to beam steering device 100. Beam steering device 100 deflects (e.g., redirects and reflects) the incident light pulse 212A to generate a deflected light pulse 212C to illuminate an object. The object can scatter the deflected light pulse 212C. A portion of the scattered light pulse returns to beam steering device 100 as a return light pulse 212D. The return light pulse 212D is guided along a path substantially similar to or parallel to the path of the deflected light pulse 212C. Beam steering device 100 can then guide the return light pulse 212D to generate a redirected return light pulse 214, which is coaxial with optical axis 211 and directed toward converging mirror 221. Converging mirror redirects (e.g., reflects) the redirected return light pulse 214 through an aperture of shield 226 toward photodetector 230.

[0052] In some embodiments, as described above, the converging lens 221 of the coaxial LiDAR scanning system 250 is configured to collect redirected return light pulses 214 along the optical axis 211 and redirect the redirected return light pulses 214 to pass through the aperture of the shield 226 to reach the photodetector 230. Figure 2C In the depicted example, the converging mirror 221 may be a near-100% reflector positioned at or near the optical axis 211, which is along the optical path of both the redirected optical pulse 212C and the redirected return optical pulse 214. The converging mirror 221 focuses the redirected return optical pulse 214 onto the photodetector 230. It should be understood that in some embodiments, the converging mirror 221 may be configured to be non-concentric with the optical axis 211. The converging mirror 221 may be made of any substrate (e.g., glass, plastic, metal, etc.) having a mirror finish layer. In some examples, an antioxidant layer is applied to the mirror finish layer to hermetically isolate the reflective layer from air. This prevents oxygen and other corrosive agents (e.g., corrosive gases or liquids) from darkening the reflective portion of the surface of the converging mirror 221.

[0053] exist Figure 2C In the depicted example, the beam steering device 100 can be Figure 1B A coaxial beam steering device 100. In some embodiments, the beam steering device 100 may be a bicoaxial device that realizes two substantially parallel light pulses directed toward one or more objects in the field of view. The beam steering device 100 may be configured to guide the incident light pulse 212A in both the vertical and horizontal directions to generate a steering light pulse 212C, while collecting a return light pulse 212D along substantially the same optical path as the steering light pulse 212C. For example, as Figure 2CAs shown, the optical path of the returning optical pulse 212D can be substantially parallel to at least a portion of the optical path of the redirecting optical pulse 212C. In this way, the optical path of the returning optical pulse 212D overlaps with the optical path of the redirecting optical pulse 212C.

[0054] like Figure 2C As depicted, in some embodiments, the photodetector 230 is configured to be substantially concentric with the reflected optical axis 211'. In some embodiments, the reflected optical axis 211' extends from the converging mirror 221 (e.g., the center of the aperture of the converging mirror 221) through the focal point of the converging mirror 221. The reflected optical axis 211' may form an angle with the optical axis 211, which is substantially parallel to the optical path of the redirected light pulse 212C and the redirected returning light pulse 214. The photodetector 230 may be a photodiode, an avalanche photodiode, etc. In some embodiments, similar to... Figure 2B The photodetector 230 shown may include a reflective surface (e.g., a mirror) on the opposite side of the light incident surface. This reflective surface can redirect (e.g., reflect) light back to the absorption region of the photodetector 230, thereby improving detection efficiency and sensitivity. In some embodiments, a mask 226 may be part of the photodetector 230.

[0055] exist Figure 2C In the illustrated examples, light source 220 may be a laser source. In some examples, the laser generated by light source 220 may have wavelengths in the visible spectrum. In some examples, the laser may have wavelengths in the infrared spectrum. In some examples, the laser may have wavelengths in the ultraviolet spectrum.

[0056] Figure 3 A dual coaxial LiDAR scanning system 300 is shown. (Example) Figure 3 The depicted dual-coaxial LiDAR scanning system 300 may include a light source 220, a reflector 222, a partial reflector 322, a first converging lens 224A, a second converging lens 224B, a first shield 226A with an aperture, a second shield 226B with an aperture, a first photodetector 230A, a second photodetector 230B, and a dual-beam steering device 100'. Figure 3 As depicted, an incident light pulse 212A generated from light source 220 is guided to a partial reflector 322, which reflects a first portion of the incident light pulse 212A to generate a redirected light pulse 212B. Polyhedron 102 generates a redirected light pulse 212C based on the redirected light pulse 212B, which is then redirected by concave reflector 112 to generate a deflected light pulse 312A. The deflected light pulse 312A can be guided through aperture 118 of beam deflector 100' to an object in the field of view (FOV). Figure 3In the depicted example, the partial reflector 322 is a 50% reflector disposed along the first optical axis 311A. The partial reflector 322 can be configured to reflect, for example, 50% of the incident light along the first optical axis 311A. In some embodiments, the partial reflector 322 can be configured to reflect more than 50% of the incident light along the first optical axis 311A. In some embodiments, the partial reflector 322 can be configured to reflect less than 50% of the incident light along the first optical axis 311A. It should be understood that the partial reflector 322 should be small enough not to block a large portion of the first returned light pulse 207A.

[0057] like Figure 3 As depicted, another portion of the incident light pulse 212A passes through the partial reflector 322 and becomes a second portion of the incident light pulse 212A. This second portion of the incident light pulse 212A can be redirected to the reflector 222, which redirects the second portion of the incident light pulse 212A to generate a redirected light pulse 213B. The polyhedron 102 generates a redirected light pulse 213C based on the redirected light pulse 213B, which is then redirected by the concave reflector 112 to generate a deflected light pulse 312B. The deflected light pulse 312B can be directed along the second optical axis 311B through the aperture 118 of the beam deflector 100. Figure 3 In the illustrated example, reflector 222 can be a near 100% reflector positioned at the second optical axis 311B. It should be understood that reflector 222 should be small enough not to block a large portion of the returned light pulse 207B. It should also be understood that, although... Figure 3 The diagram shows two portions of the incident light pulse 212A generated from the light source 220, but these two portions of the incident light pulse 212A can be generated separately using two separate and independent light sources.

[0058] Figure 3 The dual-beam steering device 100' shown can be Figure 1BThe depicted coaxial beam steering device 100 differs in that the beam steering device 100' is configured to guide two optical pulse beams (e.g., a first steering optical pulse 312A and a second steering optical pulse 312B) to illuminate one or more objects in the field of view. For example, the beam steering device 100' can be configured to guide the first steering optical pulse 312A and the second steering optical pulse 312B in both the vertical and horizontal directions while collecting the first return optical pulse 207A and the second return optical pulse 207B. The first return optical pulse 207A and the second return optical pulse 207B can have optical paths that are substantially the same as or parallel to the optical paths of the first steering optical pulse 312A and the second steering optical pulse 312B, respectively. Therefore, the optical paths of the first return optical pulse 207A and the second return optical pulse 207B overlap with the optical paths of the first steering optical pulse 312A and the second steering optical pulse 312B, respectively. In some embodiments, the dual-coaxial LiDAR scanning system 300 may further include a power controller (not shown) configured to dynamically control the power of the light source 220. Control of the power of the light source 220 may be based on the cross-sectional area of ​​the aperture associated with the return light pulses 207A-B. Controlling the power of the light source 220 can compensate for aperture variations within the field of view.

[0059] exist Figure 3 In the depicted example, the dual-beam steering device 100' can typically be asymmetrical in the xz plane. Therefore, the geometry of the optical components used to generate the first steering light pulse 312A can be asymmetrical with the geometry of the optical components used to generate the second steering light pulse 312B at any given time. Similarly, the geometry of the optical components used to guide the first return light pulse 207A can be asymmetrical with the geometry of the optical components used to guide the second return light pulse 207B at any given time. Therefore, the optical path of the first steering light pulse 312A can be scanned in a different range and pattern than that of the second steering light pulse 312B.

[0060] refer to Figure 3Similar to those described above, the first return light pulse 207A and the second return light pulse 207B can be guided by the dual beam steering device 100' through the aperture 118 toward the first converging lens 224A and the second converging lens 224B. Similarly, the first return light pulse 207A and the second return light pulse 207B can be reoriented by the polyhedron 102 and the concave reflector 112 to generate the first reoriented return light pulse 214A and the second reoriented return light pulse 214B, respectively. In some embodiments, the first converging lens 224A of the coaxial LiDAR scanning system 300 is configured to collect the first reoriented return light pulse 214A along the first optical axis 311A ​​and guide the first reoriented return light pulse 214A through the aperture of the first shield 226A to the first photodetector 230A. Similarly, the second converging lens 224B of the coaxial LiDAR scanning system 300 is configured to collect the second redirected return light pulse 214B along the second optical axis 311B and guide the second redirected return light pulse 214B through an aperture in the second shield 226B to the second photodetector 230B. Both the first converging lens 224A and the second converging lens 224B can be made of any transparent material (such as high-refractive-index glass, plastic, etc.). Figure 3 In the depicted example, the first converging lens 224A is not concentric with the first optical axis 311A, and the second converging lens 224B is not concentric with the second optical axis 311B. It should be understood that in some embodiments, one or both of the first converging lens 224A and the second converging lens 224B may be concentric with the first optical axis 311A ​​and the second optical axis 311B, respectively.

[0061] like Figure 3As depicted, in some examples, the first photodetector 230A may be located at or near the focal region of the first converging lens 224A. Similarly, the second photodetector 230B may be located at or near the focal region of the second converging lens 224B. Therefore, the first redirected return light pulse 214A may be focused on the first photodetector 230A, and the second redirected return light pulse 214B may be focused on the second photodetector 230B. One or both of the first photodetector 230A or the second photodetector 230B may be a photodiode, an avalanche photodiode, etc. In some embodiments, similar to the photodetector 230 described above, one or both of the first photodetector 230A or the second photodetector 230B may include a reflective surface (e.g., a mirror) facing the opposite side of the light incident surface. The light incident surface may redirect (e.g., reflect) the light back to the absorption region of the first photodetector 230A or the second photodetector 230B, respectively. Therefore, the efficiency and sensitivity of the first photodetector 230A and the second photodetector 230B can be improved. In some embodiments, the first mask 226A may be part of the first photodetector 230A. In some embodiments, the second mask 226B may be part of the second photodetector 230B.

[0062] exist Figure 3 In the illustrated examples, light source 220 may be a laser source. In some examples, the laser generated by light source 220 may have wavelengths in the visible spectrum. In some examples, the laser may have wavelengths in the infrared spectrum. In some examples, the laser may have wavelengths in the ultraviolet spectrum.

[0063] like Figure 3 As shown, in some examples, the dual-coaxial LiDAR scanning system 300 includes a microprocessor 306, a light source 220, a first photodetector 230A, a second photodetector 230B, and one or more motors 302. The microprocessor is electrically coupled to a computer-readable medium / memory 304. The microprocessor in the dual-coaxial LiDAR scanning system 300 can execute software. Software can include, for example, instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, application programs, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or others.

[0064] In some implementations, the microprocessor 306 can be configured to determine the distance to one or more objects in the field of view. For example... Figure 3As depicted, the microprocessor 306 includes a timer / clock module 308 and a calculator 310, which are configured to calculate the distance to one or more objects based on the time difference between the emitted turning light pulse 312A and the first return light pulse 207A detected for each corresponding light pulse.

[0065] The timer / clock module 308 is configured to timestamp each transmitted or received optical pulse. The timestamp is an encoded date and time. Examples of timestamps include “month-day-year@hour:minute:second”, “month-day-year@hour:minute:second”, “year-day-month@hour:minute:second”, “1234567890 (Unix time)”, etc. In some implementations, transmitting a redirecting optical pulse triggers the timer / clock module 308 to timestamp the redirecting optical pulse. The timer / clock module 308 can also pair the redirecting optical pulse with a corresponding return optical pulse and determine the time difference based on the timestamp.

[0066] Calculator 310 is configured to calculate the distance to one or more objects based on a time difference. In some examples, calculator 310 can multiply the time difference by the speed of light and then divide by 2 (assuming the light path is symmetrical) to determine the distance to the object. For example, if the time difference is 0.8 microseconds, calculator 310 will calculate the distance to the object as approximately 120 meters (e.g., (0.8 * 10^2)). -6 )*(2.9979*10 8 (2). After calculating the distance, the calculator 310 can store the value in a computer-readable medium / memory 304.

[0067] Computer-readable medium / memory 304 is electrically coupled to microprocessor 306 and can store identifiers associated with steering light pulses emitted into the field of view, identifiers associated with return light pulses, timestamps, determined distances, etc. In some examples, a unique identifier can be assigned to each pulse (e.g., steering light pulses emitted into the field of view and / or return light pulses). Identifying the pulses makes it possible to determine the time difference between the corresponding emitted and returned light pulses.

[0068] In some embodiments, the microprocessor 306 may optionally include a rotation controller 312. The rotation controller 312 is configured to control a first rotational speed of the concave reflector 112 and a second rotational speed of the polyhedron 102. The rotation controller 312 is electrically coupled to one or more motors 302, which are operatively coupled to the concave reflector 112 and the polyhedron 102. In some examples, the rotation controller 312 can change the first rotational speed of the concave reflector 112 and the second rotational speed of the polyhedron 102 by varying the drive current flowing to the one or more motors 302.

[0069] In some embodiments, the rotation controller 312 is configured to superimpose a random disturbance onto the control parameters to cause the first rotational speed of the concave reflector 112 and / or the second rotational speed of the polyhedron 102 to increase proportionally with the random disturbance. This random disturbance to the first rotational speed of the concave reflector 112 and / or the second rotational speed of the polyhedron 102, in the case that the optical pulses are substantially periodic (e.g., equally spaced), causes a random distribution of the horizontal and vertical scan angles associated with the optical pulses emitted from the beam steering device 100'. This facilitates more random subframe coverage. In some examples, the rotation controller 312 may set the first rotational speed of the concave reflector 112 to 10 rps and the second rotational speed of the polyhedron 102 to 500 rps. The rotation controller 312 may additionally add a disturbance of ±1 rps to one or both of the first and second rotational speeds of the concave reflector 112 and the polyhedron 102. In some cases, this disturbance may be the same, while in others it may be different.

[0070] One or more motors are operatively coupled to the concave reflector 112 and the polyhedron 102. In some examples, a first motor can rotate the concave reflector 112, while a second motor can rotate the polyhedron 102. In some examples, a single motor coupled to one or more gears can rotate both the concave reflector 112 and the polyhedron 102. Figure 3 In the depicted example, one or more motors 302 may be configured to rotate the concave reflector 112 about a first axis 106 at a first rotational speed and the polyhedron 102 about a second axis 104 at a second rotational speed. In some embodiments, the first and second rotational speeds are controlled to be independent of each other.

[0071] Figure 3 The diagram shows the first steering light pulse 312A and the second steering light pulse 312B being guided along the positive z-axis. The positions of the polyhedron 102 and the concave reflector 112 for generating the first steering light pulse 312A and the second steering light pulse 312B guided along the positive z-axis are shown below. Figure 3 These positions, as depicted, can be defined as nominal positions. When the polyhedron 102 and the concave reflector 112 rotate at a specific angle, the beam steering device 100 can guide the steering light pulse to any desired direction in the field of view and collect the return light pulse from any desired direction in the field of view. Figure 4A An exemplary beam steering device 100 is shown, which directs a beam of light to a direction between the positive x-axis and the positive z-axis and collects a returning beam of light from that direction. In some examples, such as Figure 4AAs depicted, the instantaneous position of the rotating polyhedron 102 is at +15° relative to its nominal position, while the instantaneous position of the rotating concave reflector 112 is at its nominal position. For example... Figure 4A As depicted, a light pulse 307A is guided through an aperture 118 of a beam steering device 100 and then reoriented (e.g., reflected) by a polyhedron 102 to generate a reoriented light pulse 307B. This reorientation may occur at or near point 402, and the reoriented light pulse 307B may be guided toward a concave reflector 112. The reoriented light pulse 307B is further reoriented (e.g., reflected) by a reflective surface (e.g., a mirror) of the concave reflector 112 to generate a first steering light pulse 312A. This reorientation may occur at or near point 404, and the first steering light pulse 312A may be guided toward one or more objects in the field of view in a direction between the positive x-axis and the positive z-axis. The first steering light pulse 312A illuminates an object, and a first returning light pulse 207A returns along an optical path substantially coaxial with or parallel to the first steering light pulse 312A. Figure 4A In the depicted example, the first returning light pulse 207A overlaps with the first redirecting light pulse 312A. For example, the first redirecting light pulse 312A illuminates an object at an angle of approximately 30° toward the horizontal (e.g., a 30° angle between the positive z-axis and the direction of the emitted light pulse 312A), and the exemplary beam redirecting device 100 collects the first returning light pulse 207A at an angle of approximately 30° toward the horizontal. Similar to those described above, the first returning light pulse 207A can be redirected by the polyhedron 102 and the concave reflector 112 to generate a redirected returning light pulse 214A.

[0072] Figure 4B An exemplary beam steering device 100 is shown, which directs steering light pulses into the field of view and collects returning light pulses from a direction between the negative x-axis and the positive z-axis. In some examples, such as Figure 4B As depicted, the instantaneous position of the rotating polyhedron 102 is at -5° (or 355°) relative to its nominal position, while the instantaneous position of the rotating concave reflector 112 is at its nominal position. For example... Figure 4BAs depicted, a light pulse 307A is guided through an aperture 118 of a beam steering device 100 and then reoriented (e.g., reflected) by a polyhedron 102 to generate a reoriented light pulse 307B. This reorientation may occur at or near point 402, and the reoriented light pulse 307B may be guided toward a concave reflector 112. The reoriented light pulse 307B is further reoriented (e.g., reflected) by the reflective surface (e.g., a mirror) of the concave reflector 112 to generate a first steering light pulse 312A. This reorientation may occur at or near point 404, and the first steering light pulse 312A may be guided toward one or more objects in the field of view in a direction between the negative x-axis and the positive z-axis. The first steering light pulse 312A illuminates an object, and a first returning light pulse 207A returns along an optical path substantially coaxial with or parallel to the first steering light pulse 312A. Figure 4B In the depicted example, the first returning light pulse 207A overlaps with the first redirecting light pulse 312A, wherein the first redirecting light pulse 312A illuminates the object at an angle of approximately -10° toward the horizontal direction (e.g., the -10° angle between the positive z-axis and the direction of the first redirecting light pulse 312A), and the exemplary beam redirecting device 100 collects the first returning light pulse 207A at an angle of approximately -10° toward the horizontal direction. Similar to those described above, the first returning light pulse 207A can be redirected by the polyhedron 102 and the concave reflector 112 to produce a redirected returning light pulse 214A.

[0073] In some embodiments, the beam steering device 100 can be configured to emit light pulses in a direction more toward the edge of the field of view and collect the returning light pulses from that direction. Figure 5 An exemplary beam steering device 100 is shown, which directs the beam pulse toward a direction more toward the edge of the positive horizontal range of the field of view and collects the returning light from that direction. Figure 5 As shown, the instantaneous position of the rotating polyhedron 102 is 15° relative to its nominal position, while the instantaneous position of the rotating concave reflector 112 is 30° relative to its nominal position. Figure 5As depicted, a light pulse 307A is guided through the aperture 118 of the beam steering device 100 and then reoriented (e.g., reflected) by the polyhedron 102 to generate a reoriented light pulse 307B at or near point 402. This reorientation can guide the reoriented light pulse 307B toward the concave reflector 112. The reoriented light pulse 307B is further reoriented (e.g., reflected) by the reflective surface (e.g., a mirror) of the concave reflector 112 to generate a first steering light pulse 312A at or near point 404. This reorientation can guide the steering light pulse 312A toward one or more objects in a direction more toward the edge of the field of view. The first steering light pulse 312A illuminates the object, and a first returning light pulse 207A returns along an optical path substantially coaxial with or parallel to the first steering light pulse 312A. Figure 5 In the depicted example, the first returning light pulse 207A overlaps with the first redirecting light pulse 312A. For example, the first redirecting light pulse 312A illuminates the object at an angle of approximately 40° toward the positive x-direction (e.g., the 40° angle between the positive z-axis and the projection of the redirecting light pulse 312A onto the XZ plane) and at an angle of approximately -7° toward the y-direction (e.g., the 7° angle in the negative y-direction between the z-axis and the projection of the redirecting light pulse 312A onto the YZ plane), and the exemplary beam redirecting device 100 collects the first returning light pulse 207A at an angle of approximately 40° toward the positive x-direction and at an angle of approximately -7° toward the y-direction. Similar to those described above, the first returning light pulse 207A can be redirected by the polyhedron 102 and the concave reflector 112 to produce a redirected returning light pulse 214A.

[0074] In some embodiments, to further extend the scanning range, a concave lens or cylindrical lens may be positioned in the optical path of the beam steering pulse 312A and / or the second beam steering pulse 312B as they are emitted from the beam steering device 100. This configuration can further extend the horizontal and / or vertical scanning range. In some examples, including a convex lens can also widen the optical angle, but this may reduce resolution.

[0075] Figure 6A and Figure 6B A dual coaxial LiDAR scanning system 300 is shown. Figure 3 Interlaced frames showing the angular distribution in the horizontal and vertical directions. Figures 6A to 6BFigures 600A-B show the results of a simulation experiment in which the dual-coaxial LiDAR scanning system 300 was configured to collect data over approximately 50 milliseconds. These figures illustrate a combination of three consecutive subframes forming a frame, corresponding to approximately 20 frames per second (fps). To form the first subframe 604, the dual-coaxial LiDAR scanning system 300 samples one or more objects continuously across the field of view in both the horizontal and vertical directions at periodic intervals. While doing so, the concave reflector 112 (such as...) Figure 4A , Figure 4B or Figure 5 The laser beam (as shown) is redirected (e.g., reflected) by a reflective surface (e.g., a mirror). Figures 4A to 4B as well as Figure 5 As shown, the beam spot at or near point 404 moves across the mirror at one of the facets of polyhedron 102, causing the beam spot to move from one edge of the mirror to the other. To form the second subframe 606, the dual-coaxial LiDAR scanning system 300 samples one or more objects continuously across the field of view at periodic intervals, except that the scans in the horizontal and vertical directions are slightly deviated from the scans used to generate the first subframe 604. Due to this scan deviation, the beam moves across the mirror at one of the facets of polyhedron 102, causing the beam spot to move from one edge of the mirror to the other. To form the third subframe 608, the dual-coaxial LiDAR scanning system 300 samples one or more objects continuously across the field of view at periodic intervals, except that the scans in the horizontal and vertical directions are slightly deviated from the scans used to generate the first subframe 604 and the scans used to generate the second subframe 606. The first subframe 604, the second subframe 606, and the third subframe 608 are interleaved to form a single frame with a high sample density, where the higher sample density corresponds to a higher resolution. The single frame also represents motion correction for both the movement of the LiDAR scanning system and the movement of the object being detected.

[0076] like Figure 6AAs depicted, the rasterized points of the frame generated by the directional light pulse 312A form a pattern covering the ranges of approximately -10° to 40° in the x-direction and -30° to 30° in the y-direction. Similarly, the rasterized points of the frame generated by the directional light pulse 312B form a pattern covering the ranges of approximately -40° to 10° in the x-direction and -30° to 30° in the y-direction. Within the scope of the dual coaxial LiDAR scanning system 300, there is an overlap region 602 between the first directional light pulse 312A and the second directional light pulse 312B. This overlap provides denser data sampling at the center of the field of view (e.g., approximately between -10° and 10° in the x-direction and between -30° and 30° in the y-direction). Therefore, the resolution is higher in the overlap region 602.

[0077] Figure 6A and Figure 6B The shape of the rasterized frame pattern depicted is based on the geometry of the dual-beam steering device 100' (e.g., the geometry of the polyhedron 102 and the concave reflector 112). Multiple factors obstructing the light path may contribute to... Figure 6A and Figure 6B The entire rasterized frame pattern depicted. For example, refer to... Figures 4A to 4B , Figure 5 as well as Figures 6A to 6B In some cases, the first steering light pulse 312A may miss the concave reflector 112 at a specific angle, which determines the end of the scanning range of the dual-beam steering device 100'. These may correspond to the horizontal peripheral range. Generally, in some embodiments, the scanning range of the dual-beam steering device 100' can guide the first steering light pulse 312A between approximately -10° and 40° in the x-direction and between approximately -30° and 30° in the y-direction. Similarly, the scanning range of the dual-beam steering device 100' can guide the second steering light pulse 312B between approximately -40° and 10° in the x-direction and between -30° and 30° in the y-direction.

[0078] Figure 6B A magnified portion of the frame diagram showing the angular distribution in the horizontal and vertical directions of the dual coaxial LiDAR scanning system 300 is shown. Figure 6B This more clearly illustrates the combination of three consecutive subframes (e.g., first subframe 604, second subframe 606, and third subframe 608). As described above, if a perturbation is added to the rotational speed of the polyhedron 102 and / or the rotational speed of the concave reflector 112, the angular distribution in the horizontal and vertical directions may be random.

[0079] In some examples, Figure 6A and Figure 6BThe subframes and / or frames depicted in the image can be mapped to 3D space to form a "point cloud". For example, Figure 6A and Figure 6B The two-dimensional location of light scattering on the object is depicted. In some examples, the calculator 310 of the microprocessor 306 (in...) Figure 3 (As shown in the diagram) can provide a third dimension (e.g., distance at corresponding horizontal and vertical angles). Therefore, the shape of objects around the LiDAR scanning system 300 can be reconstructed (e.g., by analyzing a “point cloud” using data analysis algorithms).

[0080] In some examples, objects located within the field of view may move or shift during the scanning process used to form a frame or subframe. For instance, in some cases, the time span of a light pulse within a frame may be quite short (e.g., less than 1 millisecond), meaning that objects (both the dual coaxial LiDAR scanning system 300A and the objects in the field of view) do not move significantly. In such cases, the sampling points in the point cloud of the frame are collected substantially simultaneously. However, in some cases, this time span may be relatively long (e.g., 20 to 50 milliseconds), sufficient for one or more objects to move a measurable distance. For example, an object moving at approximately 65 miles per hour could move approximately 2 feet in 20 milliseconds. Therefore, the position of each point in the point cloud of the frame can be compensated for by the movement of the LiDAR itself and the speed at which moving objects in the field of view are detected.

[0081] To accommodate this movement of objects, the dual-coaxial LiDAR scanning system 300 can determine the sampling rate from one or more subframes, determine the relative velocity of one or more objects, and compensate for the aforementioned sampling rate and relative velocity when forming a point cloud of three-dimensional points based on compensated aggregation distance. It should be understood that data collected at any arbitrary time interval can be aggregated to form a frame of the point cloud. Therefore, the density of the point cloud may be greater or less than the density described above.

[0082] Figure 7 A thermal diagram 700 corresponding to the collection aperture area of ​​a dual coaxial LiDAR system with certain system parameter values ​​is shown, wherein Figure 1, Figure 3 , Figure 4A , Figure 4B and Figure 5 The collection cross-sectional areas of the first redirected return light pulse 214A and the second redirected return light pulse 214B depicted are shown in the figure. Figure 7 In the center, and overlapping at the center of the field of view. Therefore, the area of ​​the collecting aperture varies with the angle of the polyhedron 102 and the angle of the concave reflector 112. For example, Figure 4A The cross-sectional area of ​​the first redirected return light pulse 214A depicted is smaller than Figure 4BThe cross-sectional area of ​​the first redirected return light pulse 214A is depicted. Therefore, with... Figure 4A The intensity of the collected light corresponding to the configuration of the polyhedron 102 and the concave reflector 112 at the depicted angle is less than Figure 4B The light intensity described is for a first steering light pulse 312A of the same intensity, the same reflectivity, and the same distance from the object in the field of view.

[0083] exist Figure 7 In the depicted example, the central region of thermal image 700, corresponding to approximately -10° to 10° in the x-direction and -30° to 30° in the y-direction, has a high collection aperture. This region is formed in an hourglass shape by double optical paths overlapping in substantially the same area. Regions corresponding to approximately -35° to -30° in the x-direction and approximately -5° to 5° in the y-direction, and regions corresponding to approximately 30° to 35° in the x-direction and approximately -5° to 5° in the y-direction, have low collection apertures originating from the tilt angle at the concave reflector 112.

[0084] In some implementations, the light source 220 (in) Figure 2B , Figure 2C and Figure 3 The power of the incident light pulse 212 (shown in the figure) can be varied based on the collecting aperture. Changing the power of the incident light pulse 212 can compensate for the changes in the collecting aperture size of the first redirected return light pulse 214A and the second redirected return light pulse 214B in the vertical and horizontal directions of the field of view.

[0085] Figure 8 An exemplary method 800 for LiDAR scan detection according to this disclosure is shown. Method 800 can be performed by a system set up or included in a vehicle, such as... Figures 1A to 1B , Figures 2A to 2C , Figure 3 , Figures 4A to 4B and Figure 5 The various systems described, and those described in detail below. Figures 9A to 9D , Figures 10A to 10B and Figure 11 The system described. For example... Figure 8 As shown, at box 802, the first light source of the LiDAR scanning system can provide one or more first light pulses. In the example described herein, the first light source can be a laser source. It should be understood that the first light source can be an incandescent lamp, a fluorescent lamp, etc. Furthermore, the first light source can have one or more wavelengths in the visible spectrum, one or more wavelengths in the infrared spectrum, or one or more wavelengths in the ultraviolet spectrum.

[0086] At frame 804, the beam steering device of the LiDAR scanning system can redirect the first light pulse to illuminate the object along the optical path. This beam steering device can be configured to emit a single light pulse (e.g., as shown in the image). Figure 1B The coaxial beam steering device 100 of the described light pulse 312A, or configured to emit dual-beam light pulses (e.g., as shown in the image), is also used. Figure 3 The depicted light pulses 312A and 312B are represented by a dual coaxial beam steering device 100'. During continuous scanning, rotation of the beam steering device (e.g., polyhedron 102) and the concave reflector (e.g., concave reflector 112) can cause the reflective facets of the beam steering device and the concave reflector in the light pulse path to change over time. The angle at which the beam steering device causes the light pulse to be steered can be calculated using the rotational positions of the beam steering device and the concave reflector. It should be understood that, in some embodiments, the rotational positions of the beam steering device and the concave reflector can trigger the light source to emit a light pulse.

[0087] At box 806, in some examples, a beam steering device (e.g., beam steering device 100 or dual beam steering device 100') can collect and redirect returning light pulses (e.g., a first returning light pulse 207A generated based on a first steering light pulse 312A illuminating an object). The collected returning light pulses can be coaxially aligned or parallel to the optical path. The returning light pulses can be redirected toward the receiving optics by the concave reflector and the beam steering device. When using a beam steering device, in some examples, the steering light pulse and the returning light pulse can be coaxially aligned. Furthermore, the beam steering device can emit steering light pulses while collecting returning light pulses in parallel or substantially simultaneously. For example, the time it takes for the emitted steering light pulse to travel to illuminate an object and return along the same optical path is somewhat instantaneous relative to the positions of the beam steering device (e.g., polyhedron 102) and the concave reflector. For example, for an object approximately 150 meters away, the flight time of the light pulse is approximately 1 microsecond. This corresponds to a rotation of approximately 0.18° of the beam steering device (e.g., polyhedron 102 rotating at 500 rpm).

[0088] At box 808, the receiving optical system, including the optical converging device, can further guide (e.g., converge or focus) the redirected return light pulse to the photodetector (e.g., Figure 3 The first photodetector 230A is depicted. In some examples, the light converging device may be a converging lens 224. Figure 2B ) or converging lens 221 ( Figure 2C ).

[0089] At box 810, the microcontroller / processor can calculate (e.g., determine) the distance from the LiDAR scanning system to the object based on the time difference between emitting the redirecting light pulse and detecting the corresponding return light pulse. The flight time of the light pulse along the optical path is proportional to the distance the light pulse travels to illuminate the object. Generally, this flight time of the light pulse illuminating the object is about half the time required to detect the light pulse.

[0090] At optional box 812, the microcontroller can generate one or more subframes (e.g., first subframe 604, second subframe 606, third subframe 608) based on aggregated values ​​of distances to one or more objects across successive or consecutive horizontal and vertical scans. Figure 6A and Figure 6B For example, a coaxial LiDAR scanning system or a dual coaxial LiDAR system (e.g., system 300) can continuously sample one or more objects in the same field of view at periodic intervals in both the horizontal and vertical directions. The sampled (e.g., scanned) field of view can be based on a first sub-pattern similar to the first subframe 604 (e.g., ...). Figure 6A and Figure 6B (As annotated) to aggregate. A dual-coaxial LiDAR system can continuously sample one or more objects again at periodic intervals within the same field of view, except that the horizontal and vertical directions are slightly offset relative to the first subframe 604. The sampled (e.g., scanned) field of view can be aggregated according to a similar... Figure 6A and Figure 6B The second sub-pattern of the second subframe 606 is used for focusing. A dual-coaxial LiDAR system can repeatedly sample the same one or more objects at periodic intervals within the same or partially the same field of view, except that the horizontal and vertical directions are slightly offset relative to the first subframe 604 and the second subframe 606. The sampled (e.g., scanned) field of view can be grouped according to a pattern similar to... Figure 6A and Figure 6B The third sub-pattern of the third subframe 608 is used to gather.

[0091] At optional box 814, the microcontroller can interleave one or more subframes to form a frame with higher resolution. For example, as Figure 6A and Figure 6B As depicted, the LiDAR system can interleave first subframe 604, second subframe 606, and third subframe 608 to form a frame with a higher sample density. A higher sample (non-overlapping sample point) density corresponds to a higher resolution. It should be understood that the overlapping region 602 of a dual-coaxial LiDAR system (e.g., system 300) Figure 6A Many sample points in a given area can have a higher density. Therefore, in Figure 6A The overlapping region 602 shown has a higher resolution.

[0092] like Figures 2A to 2B , Figure 3 , Figures 4A to 4B and Figure 5 The depicted beam steering devices 100 and 100' include a polyhedron 102 with six facets. As explained, a polyhedron can have any number of facets (e.g., more than six or less than six). Figures 9A to 9D A different view of another exemplary embodiment of the beam steering device 900 is shown. The beam steering device 900 may be a polyhedron with more than six facets. The beam steering device 900 may be used to perform one or more steps of methods 800 and / or 1900 (e.g., in...). Figure 19 (The light pulse is redirected in boxes 1904 and 1910 shown). Figure 9A A perspective view of the beam steering device 900 is shown; Figure 9B A side view of the beam steering device 900 along the positive y-axis is shown; Figure 9C A rear view of the beam steering device 900 along the positive z-axis is shown; and Figure 9D A side view of the beam steering device 900 along the positive x-axis is shown. (Reference) Figures 9A to 9D The polyhedron 910 may include a plurality of (e.g., 18) side facets parallel to the y-axis of the polyhedron 910. In some embodiments, the polyhedron 910 may be centered on the y-axis and rotated about or along the y-axis. That is, the y-axis may be the axis of rotation of the polyhedron 910. In some embodiments, each of the plurality of side facets may be polished and may be operated in a manner similar to a reflective surface (e.g., a mirror) for emitting and collecting laser light.

[0093] refer to Figures 9A to 9D The beam steering device 900 may further include a concave reflector 920. The concave reflector 920 may include a plurality (e.g., four) of flat or curved reflective surfaces (e.g., mirrors). In some embodiments, each of the flat or curved mirrors of the concave reflector 920 may have a polygonal shape (e.g., a trapezoidal shape) or any other desired shape. In some embodiments, each of the flat or curved mirrors may have corners and / or bottom edges that are cut or trimmed so that the incident laser can pass through the concave reflector 920. For example, the corners and / or bottom edges cut in the concave reflector 920... Figures 9A to 9D As shown in the diagram. In some implementations, with Figure 1B Similar to the concave reflector 112 shown, the concave reflector 920 can rotate about or along the z-axis, and its rotational speed is independent of the rotational speed of the polyhedron 910. (Reference) Figure 9BAt the instantaneous position of the rotating polyhedron 910 and the rotating concave reflector 920, a collimated beam of one or more light pulses 930 can be guided toward the facet 940 of the polyhedron 910 in the xz plane at an angle 935 (e.g., the angle between the collimated beam of one or more light pulses 930 and the negative z direction).

[0094] Figure 10A An embodiment of a configuration for generating a collimated laser beam comprising one or more optical pulses is shown. Figure 10A As shown, light source 1010 can guide one or more light pulses toward optical lens 1020. In some embodiments, optical lens 1020 and light source 1010 can be configured to have a predetermined distance, such that an irradiating laser beam (e.g., a Gaussian beam) can be formed with a predetermined beam divergence angle. The irradiating laser beam can be guided to a small facet of polyhedron 910. Light source 1010 can be a fiber laser, semiconductor laser, or other type of laser source. Alternatively, other collimating optics (such as aspherical lenses, compound lenses, reflecting spherical surfaces, reflecting parabolic surfaces, etc.) can be used to generate a collimated laser beam. In some embodiments, concave reflector 920 can be configured to have geometrical parameter values ​​such that the irradiating laser beam can be blocked or partially blocked by one or more reflective surfaces (e.g., mirrors) of concave reflector 920 at a certain rotation angle. As described above, in concave reflector 920, a portion of the bottom edge of one or more trapezoidal mirrors (e.g., cut-out section 1030) can be cut off or exposed to allow the laser beam from the light source to pass through, such as... Figure 10A As shown.

[0095] Figure 10B Another embodiment of a configuration for generating a collimated laser beam comprising light pulses is shown. In this configuration, a light source ( Figure 10B (Not shown) A laser source such as a fiber laser, semiconductor laser, or other type of laser source generates one or more light pulses. One or more light pulses may be transmitted by an optical fiber 1042 and guided by a mirror 1040 toward a small facet of the polyhedron 910. Figure 10B The light transmission configuration shown allows optical components (e.g., optical fibers, mirrors) to be placed inside the concave reflector 920, thereby eliminating or reducing the removal of the edges of the concave reflector 920 (e.g., removing edges such as...). Figure 10A The need to reduce the size of the cut section 1030 (as shown) or the cut section 1030.

[0096] refer to Figure 9B and Figure 10BIn some implementations, the relative position and / or angle of the transmitted laser beam (e.g., a laser beam transmitted by fiber optic 1042 and mirror 1040) with respect to the axis of rotation of the reflective surface (e.g., a polygonal mirror) of polyhedron 910 can be configured such that the effective LiDAR scanning range (e.g., horizontal scan coverage angle and vertical scan coverage angle) achieves the desired coverage value. In one example, the position and / or angle of the laser beam reaching one of the facets of the polygonal mirror of polyhedron 910 is configured such that the angle 965° (in Figure 9B (as shown in the figure) Distance from the vertical direction (e.g.) Figure 9B The negative z-direction is approximately 59° to obtain a horizontal field of view of approximately 100° and a vertical field of view of 25°.

[0097] In some implementations of the optical transmission configuration, the laser beam arriving at the facets of polyhedron 910 can have different Gaussian beam parameters, such as beam waist and beam divergence angle, in the y-axis direction and in the xz-plane. Different Gaussian beam parameters can be obtained by using one or more aspherical or cylindrical lenses between the laser source and one facet of polyhedron 910. In some implementations, it is desirable and advantageous to configure the lenses or other components of the LiDAR system such that the beam waist at the location where the laser beam arrives at the facet of polyhedron 910 is very narrow. In a typical implementation, a beam waist of 0.45 mm can be obtained using a divergence angle of approximately 0.06°. A narrow or small laser beam waist (e.g., 0.2 mm) reduces the proportion or percentage of polyhedral rotation positions where a portion of the beam simultaneously arrives at two facets (e.g., the laser beam spot arrives at two facets sharing a common edge) relative to all polyhedral rotation positions reached by the beam. Since a beam arriving at two facets simultaneously can lead to difficulties in signal analysis, such a beam may be undesirable.

[0098] When a Gaussian beam has a narrow beam waist in one direction, its beam divergence angle may become larger in that direction, which may be undesirable for some implementations. For example, for a Gaussian beam with a waist width of 0.2 mm, the divergence angle may be approximately 0.14°. To reduce the beam divergence angle, in some examples, the polyhedron 910 may have curved facets with curved surfaces. In some implementations, curved surfaces may be used for the side facets of the polyhedron 910, such as... Figure 15A As shown.

[0099] Figure 15A A plurality of facets 1510A-C of an exemplary polyhedron 910 with curved surfaces are shown. Figure 15AIn the diagram, solid lines show three of the multiple facets of polyhedron 910 when using a flat surface. Dashed lines show a curved surface that can alter the Gaussian beam to reduce the beam divergence angle. Although Figure 15A The curved surface is shown as a convex surface, but those skilled in the art will understand that a concave surface can also be used for some embodiments. In another embodiment, the curved surface can also be used for the concave reflector 920. Figures 9A to 9D and Figures 10A to 10B A reflective surface (e.g., a mirror) is used to alter a Gaussian beam.

[0100] In some implementations, the portion of the polyhedron that reflects the laser beam can be configured to have a set of parameters (flat or curved surface, diameter, number of facets), while the remaining portion of the polyhedron that collects the returned light can be configured to have a different set of parameters. Figure 15B A top view of such an embodiment is shown, wherein the portion of the polyhedron 910 that reflects or emits a laser beam has curved surfaces (e.g., facets 1520A-C) and a larger diameter, while the remaining portion of the polyhedron that collects the returned light has flat surfaces with smaller diameters (e.g., facets 1522A-C). Both portions of the polyhedron 910 may have the same number (e.g., eighteen) of facets. Figure 15C A side view of this embodiment of polyhedron 910 is shown, which includes facets 1520A-N having curved surfaces for reflecting or emitting laser beams, and facets 1522A-N having flat surfaces for collecting reflected light.

[0101] Figure 15D A top view of another embodiment of the polyhedron 910 is shown. (See diagram.) Figure 15D As shown, the portion of the polyhedron that reflects the laser beam may have a first number (e.g., eighteen) facets (e.g., facets 1540A-D) that have curved surfaces and large diameters; while the portion that collects the returned light may have a second number (e.g., six) facets (e.g., facets 1542A-B) that have flat surfaces and small diameters. Figure 15E A side view of this embodiment of polyhedron 910 is shown, which includes facets 1540A-N having curved surfaces for reflecting or emitting laser beams, and facets 1542A-M having flat surfaces for collecting reflected light.

[0102] Return to reference Figure 9A and Figure 9BAs described above, a collimated beam of one or more optical pulses 930 can be directed at an angle 935 in the xz plane toward a small facet 940 of the polyhedron 910. The angle 935 can be configured such that the angle between the direction of the optical pulses 930 illuminating the laser beam and the direction of the returning light incident on the return photodetector 960 is 2N times the span angle of one side of the polyhedron 910. The span angle is the angle between two radii extending from the center of the polyhedron 910 to two adjacent edges of a small facet. Therefore, for a polyhedron with 18 small faces, the span angle is 20° (i.e., 360° / 18 = 20°). Figures 9A to 9D In an exemplary implementation, for a polyhedron with 18 faces and a span angle of 20°, the value of "N" can be 1, and the value of angle 935 can be 40°. For example... Figure 9B As shown, one or more redirected light pulses 942 generated (e.g., reflected) from facet 940 are directed to mirror 945 of concave reflector 920, then reflected by mirror 945, and then redirected to the field of view as redirecting light pulses 948.

[0103] refer to Figures 9A to 9B After one or more redirecting light pulses 948 reach an object in the field of view, they can be reflected or scattered in multiple directions, and a portion of the returning light pulse 950 can be reflected back to mirror 945 and collected by it. When the object is relatively far from the LiDAR system (e.g., more than 1 meter), the returning light pulse 950 can be approximated as a collimated beam and is in a direction substantially parallel to but opposite to the original direction of the redirecting light pulse 948. The returning light pulse 950 can be redirected by mirror 945 and then propagated in the opposite direction from the redirected light pulse 942 toward polyhedron 910.

[0104] Figure 11 An exemplary configuration of a beam steering device 1100 for effectively increasing the receiving aperture and for collecting returned light pulses from different facets is shown. (Reference) Figure 9B and Figure 11 , Figure 9B One or more returned light pulses 950 shown (e.g., light pulses collected by a LiDAR system from light pulses scattered or reflected by objects in the field of view) can correspond to Figure 11The reflected light pulse 1110 is shown. The reflected light pulse 1110 can, for example, reach the reflective surface of the concave reflector 920 (e.g., mirror 1130). After being initially reflected by mirror 1130 of the concave reflector 920, the reflected light pulse 1110 can be redirected toward the polyhedron 910. In some embodiments, one or more reflected light pulses 1110 can be scattered and can extend sufficiently in a direction perpendicular to the beam propagation. Therefore, a large portion or the entire surface of mirror 1130 can receive one or more reflected light pulses 1110 (except for the portion obscured by and within the shadow of the polyhedron 910). Thus, one or more reflected light pulses 1110 can be reflected by mirror 1130 to generate pulses of light directed to multiple portions of different facets of the polyhedron 910. For example, as... Figure 11 As shown, a portion of the returning light pulse 1120 propagating toward the polyhedron 910 can reach the facet 1140 (e.g., Figure 9B The same facet 940 shown can be reflected / redirected into light pulse 1150 by facet 1140; another part of the returning light pulse 1122 propagating toward polyhedron 910 can reach different facet 1142 and can be reflected / redirected into light pulse 1152 by facet 1142; yet another part of the returning light pulse 1124 propagating toward polyhedron 910 can reach different facet 1144 and can be reflected / redirected into light pulse 1154 by facet 1144.

[0105] refer to Figure 11 In some embodiments, the light beams reflected / reoriented by different facets of the polyhedron 910 can be collected by different receiving optical systems (e.g., systems 1160, 1162, and 1164). For example, the first receiving optical system 1160 can be positioned in the path of the light pulse 1150; the second receiving optical system 1162 can be positioned in the path of the light pulse 1152, and so on.

[0106] Figures 12A to 12C An exemplary configuration of the receiving optical system is shown. (Reference) Figure 12A , Figure 12B and Figure 12C The receiving optical system may include a refractive optical lens 1210. Figure 12A (as shown); or a composite optical lens 1220, which includes multiple optical elements (as shown); Figure 12B (as shown); or a compound focusing optics 1230, which includes a parabolic or spherical mirror and a refractive optical lens (as shown); Figure 12C (As shown). Figures 12A to 12C The refractive optical lens shown can be a spherical or aspherical lens, or a combination of both. Figures 12A to 12CAny of the receiving optical systems shown can focus substantially parallel incident light onto detector element 1240, regardless of whether the pulse of incident light may have a slightly tilted and divergent angle. Although Figures 12A to 12C Three exemplary implementations are listed, but it will be understood that other configurations of the receiving optical system can be used to achieve the same purpose.

[0107] Figures 12A to 12C The detector element 1240 shown may include a photosensitive device capable of detecting optical signals and converting them into electrical signals. Figure 13A An exemplary embodiment of a detector element 1240 that directly collects light using a photosensitizing device 1320 is shown. Figure 13A As shown, the light pulse can propagate through an optional window 1310 and reach a photosensitive device 1320, which converts the light signal into an electrical signal. The electrical signal can be further processed by circuit elements on a circuit board 1330 and can be converted into digital data for further processing. In some examples, the photosensitive device 1320 may include a refractive index matching material disposed on the surface of the photosensitive device 1320. For example, the photosensitive device 1320 may include an indium gallium arsenide material whose refractive index does not match that of air. Therefore, a refractive index matching material is disposed on the surface of the photosensitive device 1320 to mitigate or eliminate this mismatch.

[0108] Figure 13B Another exemplary embodiment of a detector element 1240 for collecting light using optical fiber 1350 is shown. (See example...) Figure 13B As shown, the light pulse received by the photosensitive device 1370 can first be focused by the optical device 1340 onto one end of the optical fiber 1350. The optical fiber 1350 can be a multimode fiber, a single-mode fiber, or a double-clad fiber, in which light entering the inner cladding of the fiber is slowly absorbed into the core. In one embodiment, the light pulse exiting from the other end of the optical fiber 1350 can be focused by the optical device 1360 onto the photosensitive device 1370, which can convert the optical signal into an electrical signal. The optical device 1360 that focuses the optical signal from the optical fiber 1350 can be an optical lens, a spherical or aspherical mirror, or directly coupled to the photosensitive device 1370 using an optional refractive index matching material disposed on the surface of the device 1370 to improve the amount of light received by the photosensitive device 1370. The electrical signal can be further processed by circuit elements on the circuit board 1380. In this embodiment, the electronic device (e.g., circuit board 1380) and / or the photosensitive device 1370 can be located remotely. Figure 11The beam steering device 1100 shown is positioned (e.g., at a distance greater than 0.1 meters, greater than 1 meter, or even greater than 5 meters) to reduce the size of the beam steering device 1100. For example, except for the light-departing end of the optical fiber 1350, the beam steering device 1100 can be configured to have a small physical size.

[0109] Return to reference Figure 11 In another embodiment, receiving optical system 1160 may be positioned in the path of light pulse 1150. In another embodiment, receiving optical system 1164 may be positioned in the path of light pulse 1154. In yet another embodiment, two or more receiving optical systems (e.g., both 1160 and 162, or all of 1160, 1162, and 1164) may coexist in the LiDAR system. In one embodiment, each of these receiving optical systems may be independent of each other, and each receiving optical system may have its own photosensor. In another embodiment, some or all of these receiving optical systems may share a single photosensor.

[0110] Figures 14A to 14B An exemplary configuration is shown for combining redirected return optical pulses from different facets using a combination of free-space optics or fiber bundles and / or power combiners. Figure 14A As shown, in some embodiments, a single photosensitive device (e.g., device 1420) can be shared among multiple receiving optical systems. In such embodiments, light pulses from beams of light from different directions can be redirected to the same photosensitive device 1420 by multiple mirrors and focusing optics (e.g., optics 1410, 1412, and 1414). For example, light pulse 1150 can be focused by focusing optics 1410, subsequently becoming a pulse of focused light 1450 and reaching photosensitive device 1420. Similarly, a pulse of light pulse 1152 can be redirected and focused by optics 1412, subsequently becoming a pulse of focused beam 1452 and reaching photosensitive device 1420. A pulse of light pulse 1154 can be redirected and focused by optics 1414, subsequently becoming a focused beam 1454 and reaching photosensitive device 1420.

[0111] Figure 14B Another embodiment of a photosensor 1440 shared among multiple receiving optical systems is shown. In this embodiment, pulses of light from each beam originating from each different direction can be focused by an optical converging device (…). Figure 14B(Not shown in the image) Focusing. Subsequently, each beam in the focused beam can be coupled to the receiver of each of the three fiber optic channels 1430, 1432, and 1434, respectively. These three fiber optic channels can be combined together to form a single optical channel using, for example, a three-to-one optical combination device (e.g., a reverse fan-out fiber bundle). The light pulses emitted from the transmitter of the combined optical channel can then be directed to a shared photosensitive device 1440. In some embodiments, instead of using an optical combination device, the light pulses emitted from the transmitter of the fiber bundle (e.g., a bundle of three fibers) can be directly focused onto a shared photosensitive device.

[0112] Figure 18 Another embodiment of the beam steering device 1800 with a wobbling mirror is shown. For example... Figure 18 As shown, the beam steering device 1800 does not include the polyhedron 910 (in... Figures 9A to 9D (As shown in the figure), it includes a single-faceted or multi-faceted oscillating mirror 1810. For a multi-faceted mirror, the angle between adjacent facets can be similar to... Figure 11 The angle (e.g., 20°) between adjacent facets of the polyhedron 910 shown. The mirror 1810 can oscillate along an axis 1820 parallel to the y-axis or along the y-axis, such that pulses of light illuminating one or more facets of the mirror 1810 can be directed in different directions along the xz plane. It should be understood that, with... Figures 15A to 15E Similar to the implementation described for the polyhedron, the portion of the oscillating mirror 1810 that reflects the irradiated light pulse may be curved, and / or may have a different size than the portion of the oscillating mirror 1810 that collects the returned light pulse.

[0113] Return to reference Figure 16 In some implementations, in order to accurately determine the time of flight of the pulse (e.g., the time it takes for the pulse emitted from the LiDAR system to be scattered / reflected by objects in the field of view and received by the detectors of the LiDAR system), it is necessary to determine the time when the pulse is emitted from the LiDAR system. Figure 16 The diagram shows a beam steering device 1610, a light source 1620, and a photosensitive device 1630. The beam steering device 1610 can be connected to... Figure 1B , Figure 4A , Figure 4B or Figure 5 The beam steering device 100 shown and Figures 9A to 9D The device 900 shown is similar to or the same as the one shown; the light source 1620 can be with Figure 2B , Figure 2C or Figure 3 The light source 220 shown and Figure 10A and Figure 10B The light source 1010 shown is similar to or the same as the light source shown; and the photosensitive device 1630 can be with Figures 12A to 12C , Figures 13A to 13B as well as Figures 14A to 14B Those shown are similar or identical. As described above, a photosensitive device may include a light detection module for detecting and converting received light signals.

[0114] refer to Figure 16 In one embodiment, the light source 1620 generates one or more light pulses based on an electrically triggered signal provided by an external or internally generated signal source. In some embodiments, the time elapsed between generating the electrically triggered signal and emitting one or more light pulses from the light source 1620 can be considered pulse-to-pulse to be constant (e.g., the variation is negligible) and / or calibrated. The electrically triggered signal can be transmitted via an electrical connector (e.g., a cable) 1640 to a photosensitive device 1630, which is then used to determine the reference timing of the light pulses.

[0115] In some implementations, an optical fiber 1650 can be used to guide a portion of one or more optical pulses emitted from the light source 1620. A beam splitter can be used to separate the optical pulses and obtain a portion of that pulse as a reference signal. This portion can be any percentage of the total optical pulse, such as 10%, 1%, 0.1%, or 0.0001%, or any desired percentage. This portion of the optical pulse can be guided by the optical fiber 1650 to a photosensitive device 1630 and then used to determine the reference time of the optical pulse emitted from the light source 1620.

[0116] In some embodiments, the reference pulse generating device 1660 may be configured together with the beam steering device 1610 to obtain a portion of the light pulse as a reference signal and to redirect this portion to the photosensitive device 1630 after the light pulse has been emitted from the light source 1620. This portion may be any percentage of the total light pulse, such as 10%, 1%, 0.1%, or 0.0001%, or any desired percentage. Those skilled in the art will understand that... Figure 16 The reference pulse generating device 1660 shown is illustrative only; and any optical component that can obtain a portion of one or more optical pulses as a reference signal and redirect them to the photosensitive device 1630 can be used. For example, the reference pulse generating device 1660 may be a partial reflection device that reflects a portion of an optical pulse to the photosensitive device.

[0117] In relation to Figure 16 In the aforementioned embodiments discussed, the reference signal (e.g., a reference light pulse) can be detected by the photosensitive device 1630. Figure 17 The reference signal is shown as reference pulse 1710. Figure 17A return light pulse 1720 is also shown. This return light pulse (e.g., a pulse reflected / scattered by an object in the field of view and received by the photosensitive device 1630) is shown as pulse 1720. Pulse 1720 may have a different intensity and pulse width than the reference pulse 1710. In some embodiments, pulses 1710 and 1720 may have similar shape profiles. In one embodiment, the reference pulse 1710 may be used as a template to match the received return pulse 1720 to accurately determine the time difference (or TOF) between the return pulse and the reference pulse. Based on the TOF, the distance of the object in the field of view can be determined.

[0118] Figure 19 The use of a LiDAR scanning system (e.g., in) is shown. Figures 1A to 1B , Figures 2A to 2C , Figure 3 , Figures 4A to 4B , Figure 5 , Figures 9A to 9D , Figures 10A to 10B as well as Figure 11 An exemplary flowchart of a method for determining the time of flight of one or more light pulses used to generate a 3D image (the various systems depicted herein). Reference Figure 19 At box 1902, one or more light pulses (e.g., short laser pulses with a pulse width of about 0.01 nanoseconds to 5 nanoseconds or light pulses with a pulse width of 5 nanoseconds to 30 nanoseconds or longer) can be generated from a light source of the LiDAR scanning system. At box 1904, a beam steering device can redirect or scan one or more light pulses in the field of view in both the horizontal and vertical directions. At box 1906, one or more light pulses, or a portion thereof, illuminate or reach an object and are scattered and reflected in one or more directions. In some embodiments, a portion of the scattered or reflected light pulses may return to the LiDAR scanning system and reach the collection aperture of the detector of the LiDAR scanning system.

[0119] At box 1910, one or more returning light pulses can be redirected or reoriented in a direction substantially opposite to and parallel to the direction of the light pulses emitted from the LiDAR scanning system. At box 1912, one or more reoriented returning light pulses can be focused onto a photodetector of the receiving optics system. At box 1914, the photodetector converts photons from the reoriented returning light pulses arriving at the photodetector into one or more electrical signals. At box 1916, an amplification circuit or device can be used to amplify one or more output electrical signals generated by the photodetector by a predetermined factor. At box 1920, the amplified one or more electrical signals can be sampled and converted into digital values ​​at a predetermined sampling rate. In some embodiments, digitized signal data can be collected over a time period corresponding to the desired maximum Time of Flight (TOF) of the object at the farthest point in the field of view. At box 1922, the digitized signal data can be analyzed to determine the TOF of one or more returning light pulses and to determine the distance from the LiDAR scanning system to the reflection or scattering point of the object.

[0120] It should be understood that the specific order or hierarchy of the boxes in the disclosed methods and / or flowcharts is illustrative of exemplary methods. Based on design preferences, it should be understood that the specific order or hierarchy of the boxes in the methods and / or flowcharts may be rearranged. Furthermore, some boxes may be combined or omitted. The appended method claims present elements of various boxes in an exemplary order, but are not intended to limit the user to the specific order or hierarchy presented.

[0121] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to limit themselves to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein, unless specifically stated otherwise, an element referred to in the singular is not intended to mean “one and only one”, but rather “one or more”. The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or more advantageous than other aspects. Unless otherwise specifically stated, the term “some” means one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and / or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” can be only A, only B, only C, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of elements throughout the various aspects described in this disclosure that are known to a person skilled in the art or will be known thereafter are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended for the general public, whether or not such disclosure is expressly recited in the claims. The words “module,” “mechanism,” “element,” “device,” etc., may not be a substitute for the word “unit.” Thus, according to 35 U.SC §112(f), any element of a claim is not subject to interpretation unless the phrase “unit for…” is used to expressly describe the element.

Claims

1. A light detection and ranging (LiDAR) system, comprising: one or more light sources configured to provide one or more light pulses; a beam steering device and a reflector of a polyhedral structure surrounded by a plurality of reflective surfaces, wherein the beam steering device is configured to direct the one or more light pulses to the reflector, wherein the reflector is configured to redirect the one or more light pulses to a field of view upon receiving the one or more light pulses from the beam steering device, and wherein the combination of the reflector and the beam steering device, when moved relative to each other, is configured to: vertically and horizontally steer the one or more light pulses to illuminate an object within the field of view, and receive return light generated based on the illumination of the object within the field of view, and direct the return light to a detector.

2. The LiDAR system of claim 1, wherein the beam steering device is a wobble mirror.

3. The LiDAR system of claim 2, wherein the wobble mirror is operative to wobble about a first axis and the reflector is operative to rotate about a second axis, wherein the combination of the wobble mirror and the reflector coaxially illuminate the object and receive the return light using the one or more light pulses based on their respective axis movements.

4. The LiDAR system of claim 2, wherein the wobble mirror is a single facet mirror.

5. The LiDAR system of claim 2, wherein the wobble mirror is a multi-facet mirror.

6. The LiDAR system of any one of claims 1-5, further comprising one or more optics disposed between the one or more light sources and the beam steering device, the one or more optics facilitating directing the one or more light pulses to the beam steering device.

7. The LiDAR system of any one of claims 1-5, wherein an angle between any two adjacent reflective surfaces of the plurality of reflective surfaces is not a 90-degree angle.

8. The LiDAR system of any one of claims 1-5, wherein the one or more light pulses form two light pulses comprising a first light beam and a second light beam, and wherein the beam steering device scans the first light beam within a first range within the field of view and scans the second light beam within a second range within the field of view, the first range overlapping the second range.

9. The LiDAR system of any one of claims 1-5, wherein the reflector is further configured to direct the return light to the beam steering device, and wherein the beam steering device is further configured to, upon receiving the return light from the reflector, direct the return light to a detector.

10. A light detection and ranging (LiDAR) system, comprising: ​ one or more light sources configured to produce one or more light beams; a beam scanner configured to scan a field of view of the LiDAR system using the one or more light beams, the beam scanner comprising a planar mirror and a polyhedral mirror surrounded by a plurality of reflective surfaces, wherein the planar mirror is pivotable along a first axis to direct the one or more light beams to the rotatable polyhedral mirror, wherein the polyhedral mirror is rotatable about a second axis that is orthogonal to the first axis to redirect the one or more light beams to a field of view, and wherein the beam scanner is optically coupled to the one or more light sources and positioned to: vertically and horizontally steer the one or more light pulses to illuminate objects within the field of view of the LiDAR system, and receive return light generated based on the illumination of the objects within the field of view, and direct the return light to a detector.

11. The LiDAR system of claim 10, wherein the plurality of reflective surfaces comprises four or more reflective surfaces.

12. The LiDAR system of claim 10 or 11, wherein the polyhedral mirror is operative to rotate about a polyhedral mirror axis that extends into a block of the polyhedral mirror through two opposing non-reflective surfaces of the block.

13. The LiDAR system of claim 10 or 11, wherein: the one or more light beams comprise a first light beam and a second light beam, the beam scanner scans the first light beam and the second light beam to define a first field of view and a second field of view, respectively, the first field of view and the second field of view, in combination, define the field of view of the LiDAR system, and the first field of view and the second field of view partially overlap to define an overlap region within the field of view of the LiDAR system.

14. The LiDAR system of claim 10 or 11, wherein: the one or more light beams comprise a first light beam and a second light beam, and the beam scanner scans each of the first light beam and the second light beam to define a respective partial field of view that is approximately 60 degrees wide in one direction.

15. The LiDAR system of claim 10 or 11, wherein the polyhedral mirror is further configured to direct the return light to the planar mirror, and wherein the planar mirror is further configured to direct the return light to the detector.

16. A light detection and ranging LiDAR system, comprising: one or more light sources configured to produce one or more light beams; a beam scanner configured to scan a field of view of the LiDAR system using the one or more light beams, the beam scanner comprising a rotatable polyhedral mirror and a second mirror, wherein the polyhedral mirror is surrounded by a plurality of reflective surfaces and is rotatable about a polyhedral mirror axis to direct the one or more light beams to the second mirror, wherein the second mirror is pivotable along an axis orthogonal to the polyhedral mirror axis to direct the one or more light beams to a field of view, and wherein the beam scanner is optically coupled to the one or more light sources and positioned to: vertically and horizontally scan the one or more light pulses to illuminate an object within the field of view of the LiDAR system, and receive return light generated based on the illumination of the object within the field of view, and direct the return light to a detector.

17. The LiDAR system of claim 16, wherein the plurality of reflective surfaces comprises four or more reflective surfaces.

18. The LiDAR system of claim 16 or 17, wherein: the one or more light beams comprise a first light beam and a second light beam, the beam scanner scans the first light beam and the second light beam to define a first field of view and a second field of view, respectively, the first field of view and the second field of view, in combination, define the field of view of the LiDAR system, and the first field of view and the second field of view partially overlap to define an overlap region within the field of view of the LiDAR system.

19. The LiDAR system of claim 16 or 17, wherein the second mirror is further configured to direct the return light to the polyhedral mirror, and wherein the polyhedral mirror is further configured to direct the return light to the detector.

20. A method of performing a LiDAR scan using a LiDAR system, comprising: directing one or more light pulses from one or more light sources to a beam steering device optically coupled to the one or more light sources, the beam steering device comprising a wobble mirror and a reflector surrounded by a plurality of reflective surfaces; directing, by the wobble mirror of the beam steering device, the one or more light pulses toward the reflector, upon receipt of the one or more light pulses from the beam steering device, directing, by the reflector, the one or more light pulses to a field of view, wherein a combination of the wobble mirror and the reflector causes the one or more light pulses to be steered vertically and horizontally to illuminate an object within the field of view, receiving return light generated based on the illumination of the object within the field of view, and directing the return light to a detector.

21. The method of claim 20, wherein the one or more light pulses form two light pulses comprising a first light beam and a second light beam, and wherein the one or more light pulses are steered by scanning the first light beam over a first range within the field of view and scanning the second light beam over a second range within the field of view, the first range overlapping the second range.

22. The method of claim 20 or 21, wherein directing the return light to the detector comprises: directing, by the reflector, the return light to the wobble mirror, and upon receipt of the return light from the reflector at the wobble mirror, directing the return light to a detector.

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