A lidar, a scanner for a lidar, and a device

Abstract

This disclosure relates to a lidar, a scanner for the lidar, and an apparatus. The lidar includes a transmitter and a scanner. The transmitter is configured to emit a probe light. The scanner is configured to oscillate about a rotation axis within an oscillation range, deflecting the probe light into a field of view. The oscillation range includes a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region along a first direction. The first direction is perpendicular to the rotation axis. The scanner rotates at a greater speed in the first fixed-speed region than it rotates at the second fixed-speed region. In the first variable-speed transition region, the scanner's rotational speed varies with angle according to a half-period cosine function.

Description

Technical Field

[0001] This disclosure relates to the field of optical detection technology, and more particularly to a lidar, a scanner for lidar, and an apparatus. Background Technology

[0002] The core performance indicators of vehicle-mounted LiDAR include angular resolution, scanning frame rate, and ranging capability. Vehicle-mounted LiDAR includes a main LiDAR and a blind spot LiDAR. The main LiDAR has higher requirements for ranging capability.

[0003] In some lidar systems, a scanner is used to scan the probe light emitted by the transmitter horizontally. With a constant horizontal angular resolution and the number of emission channels per horizontal angle, a lower scanner rotation speed results in a stronger ranging capability for the lidar. However, reducing the scanner rotation speed to improve ranging capability leads to a decrease in the scanning frame rate, affecting scanning efficiency.

[0004] Existing lidar technology struggles to balance long-range detection and scanning efficiency. Summary of the Invention

[0005] This disclosure provides a lidar, a scanner for the lidar, and an apparatus that can improve the ranging capability of the lidar while maintaining scanning efficiency.

[0006] According to a first aspect of this disclosure, a lidar is provided. The lidar includes: a transmitter configured to emit probe light; and a scanner configured to oscillate about a rotation axis within an oscillation range to deflect the probe light into a field of view. The oscillation range includes, along a first direction, a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region, the first direction being perpendicular to the rotation axis. The scanner rotates at a greater speed in the first fixed-speed region than it rotates at the second fixed-speed region. In the first variable-speed transition region, the scanner's rotational speed varies with angle according to a half-period cosine function.

[0007] Optionally, along the first direction, the swing range further includes a second speed transition zone and a third speed fixed zone, wherein the relationship between the rotational speed of the scanner and the angle in the second speed transition zone satisfies a half-cycle cosine function.

[0008] Optionally, the scanner rotates at the same speed in the third fixed speed zone as it does in the first fixed speed zone.

[0009] Optionally, along the first direction, the swing range further includes a steering transition zone; the rotational speed of the scanner in the steering transition zone varies with the angle according to a half-cycle cosine function.

[0010] Optionally, the field of view along the first direction includes a first angular range corresponding to the first fixed speed zone, a second angular range corresponding to the first variable speed transition zone, and a third angular range corresponding to the second fixed speed zone. The transmitter is also configured to emit multiple probe beams in a preset emission sequence, wherein the emission time interval of the transmitter in the first angular range is shorter than the emission time interval of the transmitter in the third angular range.

[0011] Optionally, the second angular range includes a plurality of sequentially arranged second angular sub-ranges along the first direction. In the direction from the first angular range to the third angular range, the transmission time interval of the transmitter in the plurality of second angular sub-ranges increases. In the direction from the third angular range to the first angular range, the transmission time interval of the transmitter in the plurality of second angular sub-ranges decreases.

[0012] Optionally, at least one of the first and second speed change transition zones has a swing angle range of less than or equal to 5 degrees.

[0013] Optionally, the transmitter includes multiple lasers. Within the field of view corresponding to the same fixed velocity zone, the emission time interval of the multiple lasers is associated with the field of view angle of a second direction corresponding to the multiple lasers, the second direction being perpendicular to the first direction.

[0014] Optionally, the emission time interval of the plurality of lasers is associated with the field of view of the second direction corresponding to the plurality of lasers, including: the emission time interval of the plurality of lasers is inversely correlated with the field of view of the second direction corresponding to the plurality of lasers; or, the plurality of lasers includes a plurality of laser groups, the emission time intervals of different laser groups are different, and the emission time interval of the laser group with a large field of view in the second direction is less than the emission time interval of the laser group with a small field of view in the second direction.

[0015] According to a second aspect of this disclosure, a scanner for a lidar system is provided. The scanner includes: a mirror; and a driving device configured to drive the mirror to oscillate about a rotational axis within an oscillation range. The oscillation range includes a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region along a first direction perpendicular to the rotational axis. The mirror rotates at a greater speed in the first fixed-speed region than it does in the second fixed-speed region. In the first variable-speed transition region, the mirror's rotational speed varies with angle according to a half-period cosine function.

[0016] According to a third aspect of this disclosure, a lidar is provided. The lidar includes: a transmitter configured to drive a plurality of lasers to emit multiple probe beams within a field of view according to a preset emission sequence. Along a first direction, the field of view includes a first angular range corresponding to a first fixed-speed region of a scanner, a second angular range corresponding to a first variable-speed transition region of the scanner, and a third angular range corresponding to a second fixed-speed region of the scanner. The first direction is perpendicular to the axis of rotation of the scanner. The plurality of lasers are configured to emit multiple probe beams at a preset emission sequence, wherein the emission time interval of the plurality of lasers in the first angular range is shorter than the emission time interval in the third angular range.

[0017] According to a fourth aspect of this disclosure, an apparatus is provided. The apparatus includes a lidar as described in any of the foregoing embodiments, or a scanner as described in any of the foregoing embodiments.

[0018] In this embodiment, the scanner's swing range is divided into at least two fixed-speed zones and at least one variable-speed transition zone. The scanner's rotational speed in the first fixed-speed zone is greater than its rotational speed in the second fixed-speed zone. Without changing the angular resolution and frame rate, the detection range of the LiDAR in the second fixed-speed zone is greater than that in the first fixed-speed zone. Thus, the LiDAR provided in this disclosure can increase the detection range of the LiDAR within a portion of the field of view without reducing the frame rate. In the first variable-speed transition zone, the scanner's rotational speed changes with the angle according to a half-cycle cosine function, ensuring continuous rotational speed and acceleration of the scanner and avoiding abrupt acceleration changes. This significantly reduces vibration and noise caused by mechanical shock and sudden movements, improving the scanner's motion smoothness and service life. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the following description of the embodiments will be provided as examples. The drawings described below are merely embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. The drawings are used to provide a further understanding of this disclosure and constitute a part of the specification. They are used together with the embodiments of this disclosure to explain this disclosure and do not constitute a limitation of this disclosure.

[0020] Figure 1 An example structural block diagram of an exemplary lidar consistent with some embodiments of this disclosure is shown.

[0021] Figure 2 A schematic diagram of an exemplary lidar consistent with some embodiments of this disclosure is shown.

[0022] Figure 3 A schematic diagram of an exemplary scanning scheme consistent with some embodiments of this disclosure is shown.

[0023] Figure 4 An exemplary probe profile schematic diagram consistent with some embodiments of this disclosure is shown.

[0024] Figure 5 A schematic diagram of the structure of an exemplary scanner consistent with some embodiments of this disclosure is shown. Detailed Implementation

[0025] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the specific implementation methods of this disclosure will be described below with reference to the accompanying drawings. The accompanying drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort. Adjustments and improvements made without departing from the concept of this disclosure are all within the protection scope of this disclosure.

[0026] To keep the drawings simple, each figure only schematically shows the parts related to the corresponding embodiment, and they do not represent the actual structure of the product. In addition, for the sake of simplicity and ease of understanding, some figures only schematically show parts of components with the same structure or function, and there may actually be more or fewer components with the same structure or function.

[0027] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar words used in this patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms “an” or “a” and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar words mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected,” “coupled,” or “linked” and similar words are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0028] Unless otherwise specified, all embodiments mentioned herein can be combined to form new technical solutions. Furthermore, unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0029] In this disclosure, the terms "or" and "and / or" describe the relationship between related objects and indicate a non-exclusive inclusion. For example, "A and / or B" and "A or B" can include: the presence of only "A", the presence of only "B", and the presence of both "A" and "B", where "A" and "B" can be singular or plural. As another example, "A, B, and / or C" and "A, B, or C" can include: the presence of only "A", the presence of only "B", the presence of only "C", the presence of both "A" and "B", the presence of both "A" and "C", the presence of both "B" and "C", and the presence of both "A", "B", and "C", where "A", "B", and "C" can be singular or plural. Furthermore, the symbol " / " in this disclosure indicates an "or" relationship between the related objects before and after the symbol. In this disclosure, the term "at least one A or B" has the same meaning as "A or B" described above. The term "at least one A, B, or C" has the same meaning as "A, B, or C" above. "One or more" of multiple objects refers to any one or any combination of multiple objects, such as "one or more of A, B, and C" including: "A alone", "B alone", "C alone", "A and B", "A and C", "B and C", or "A, B, and C".

[0030] Laser detection is a remote sensing technology. LiDAR (Lidar) uses lasers to measure distances and create three-dimensional (3D) images of objects and landscapes. During object detection, the lidar emits a laser beam. The laser beam is reflected off the object's surface. The reflected light (also called the echo) is received by the lidar and converted into an electrical signal. The lidar processes this electrical signal to determine information about the object, such as its distance, position, or velocity. LiDAR can also create real-time 3D models of the environment. This model can be represented as a point cloud. A point cloud is a collection of three-dimensional data points representing the surfaces of objects, structures, and environments within a specific area. Each data point in the point cloud can be defined by its X, Y, and Z coordinates in space, representing its position in three-dimensional space. Using point clouds, vehicles can accurately identify the positions of objects on the road, such as cars, pedestrians, and / or cyclists.

[0031] In some embodiments, LiDAR can generate point clouds, which simplifies and simplifies the processing of driver assistance algorithms. LiDAR provides high-resolution 3D vision for vehicles, such as intelligent vehicles, working in conjunction with cameras and radar. It can enhance a vehicle's perception capabilities to handle more complex road conditions, such as dark environments or unknown objects on highways. LiDAR can further provide high-performance automotive-grade LiDAR solutions, ensuring safer and smarter driver assistance, such as L2+ assisted driving. Once configured, LiDAR can be widely used in passenger cars and commercial vehicles equipped with advanced driver assistance systems (ADAS) and / or autonomous driving (automated transportation). LiDAR can also be applied to any suitable end device, such as drones or robots. For example, LiDAR can support robotic applications such as delivery robots and logistics robots.

[0032] In some embodiments, the lidar can be configured as a long-range lidar sensor. Long-range lidar sensors can have a long detection range (e.g., from hundreds of meters to thousands of meters). Long-range lidar sensors can detect and classify objects over a large distance range. Long-range lidar sensors can be mounted on the roof (e.g., the front and / or rear roof) or in windows, headlights, bumpers, or other locations. LiDAR can provide an unobstructed view of the road ahead and / or behind and can detect objects at greater distances. This is very useful for highway driving and for early detection of distant objects.

[0033] In some embodiments, the lidar can be configured as a short-range lidar sensor. Short-range lidar sensors have a shorter detection range (e.g., within a few meters to tens of meters around the lidar) and a wider field of view (FOV) (e.g., from 60 degrees to 360 degrees horizontally). The wider FOV allows for the detection of nearby objects and provides a more comprehensive view of the surrounding environment / objects. Short-range lidar sensors can be mounted on the roof, near the headlights, or on the side panels of the vehicle. This can improve the vehicle's perception capabilities and assist in lane keeping and / or lane changing maneuvers.

[0034] In some embodiments, the lidar can be configured as a mid-range lidar sensor. Mid-range lidar sensors strike a balance between long-range and short-range lidar sensors in terms of detection range (e.g., from a few meters to several hundred meters) and field of view (e.g., from 30 degrees to 180 degrees horizontally). Mid-range lidar sensors can be mounted on the front bumper, side panels, or rear bumper to detect objects near the vehicle. Mid-range lidar sensors are suitable for parking and detecting nearby objects during urban driving.

[0035] In some embodiments, a lidar system with multiple lidar sensors can be deployed around the vehicle. The multiple lidar sensors can be configured to have different detection ranges and fields of view to cover the area around the vehicle. In some embodiments, the lidar system may include one or more short-range lidar sensors and one or more mid-range lidar sensors. The lidar system can combine lidar sensors located at different positions on the vehicle to provide a comprehensive view of the environment. Data from these lidar sensors can be fused with data from other sensors, such as cameras and / or millimeter-wave radar. This allows for real-time decisions to be made for safe and efficient autonomous driving. Lidar sensors with different detection ranges, fields of view, and locations can be combined. This achieves a balance between long-range visibility and short-range object detection, while considering aesthetics and cost.

[0036] In some embodiments, multiple lidar sensors are activated in the lidar system. In other embodiments, these multiple lidar sensors are activated or deactivated depending on the scenario or requirements. For example, when the vehicle is traveling at high speeds (e.g., above 40 mph), one or more short-range lidar sensors can be deactivated, while one or more long-range and mid-range lidar sensors can be activated. Conversely, when the vehicle is traveling at lower speeds (e.g., below 40 mph), one or more long-range lidar sensors can be deactivated, while one or more short-range and mid-range lidar sensors can be activated. This effectively saves energy and extends the lifespan of the lidar system.

[0037] Figure 1 An example structural block diagram of an exemplary lidar consistent with some embodiments of this disclosure is shown. (Refer to...) Figure 1 The lidar 100 includes a laser emitting system 110, a laser receiving system 120, and a control and processing system 130. Optionally, the lidar 100 also includes a scanning system 140. The scanning system 140 may include a rotating optical engine, a rotating reflector, a reciprocating oscillating mirror or galvanometer (e.g., a MEMS mirror, a Galvo mirror, etc.), and other components that can direct the laser beam to different locations in the environment.

[0038] In some embodiments, the laser emitting system 110 can be used to emit a laser. When the laser encounters an object 10, it is reflected from the surface of the object 10, forming an echo. The echo can return to the lidar 100. The laser receiving system 120 can receive the reflected echo and convert it into an electrical signal. This electrical signal, after preprocessing, determines the echo data (e.g., the echo reception time) and provides it to the control and processing system 130. The control and processing system 130 can process the echo data to determine information about the object 10, such as its distance, position, or velocity. Repeating this process multiple times can create an accurate, real-time 3D environment map, such as a point cloud. Computers in terminal devices such as vehicles can use the point cloud for safe navigation.

[0039] In some embodiments, the laser emitting system 110 may include a driving circuit, a laser, and an emitting optics. The laser emits laser light under the drive of the driving circuit, and the laser light exits through the emitting optics. The laser may include a semiconductor laser, such as a vertical-cavity surface-emitting laser (VCSEL), an edge-emitting laser (EEL), or other semiconductor lasers capable of generating laser light. In other embodiments, the laser may also include a fiber laser. The wavelength of the laser emitted by the laser may be any one of 905 nm, 940 nm, or 1550 nm. The laser may also emit laser light of other wavelengths. The driving circuit may include a driver integrated circuit, such as an analog chip or a digital-analog hybrid chip. Multiple lasers in the emitter may constitute multiple independent light-emitting channels.

[0040] In some embodiments, the laser receiving system 120 may include a receiving optics and a detector. The receiving optics collects echoes reflected from an object. The receiving optics focuses the echoes onto the detector. The detector converts the echoes into electrical signals using the photoelectric effect. The detector may include a photodetector circuit, an avalanche photodiode (APD), a single-photon avalanche diode (SPAD), a silicon photomultiplier (SiPM), or a similar device. The laser receiving system 120 may also include a preprocessing circuit. The preprocessing circuit may include digitization circuitry. For example, the preprocessing circuit may include an analog-to-digital converter (ADC). The ADC converts analog signals into digital signals and provides them to the control and processing system 130. Alternatively, the preprocessing circuit may include a time-to-digital converter (TDC). The echoes are detected and converted into electrical signals by the receiver. These electrical signals are provided to the TDC. Based on the received electrical signals, the TDC can determine the timing information (e.g., a timestamp) of the echoes. The TDC can convert time information into digital signals and provide them to the control and processing system 130. The preprocessing circuit may also include analog front-end circuitry for channel selection and analog signal amplification. In some embodiments, the preprocessing circuit may be implemented as a system-on-chip (SOC) or an application-specific integrated circuit (ASIC). For example, the detector may be integrated onto a photosensitive chip. The photosensitive chip may be 3D stacked with the chip including the preprocessing circuitry. The emitting and receiving optics may include, for example, one or more optics such as lenses / lens groups, mirrors, filters, beam splitters, apertures, homogenizers, etc. The emitting and receiving optics may be independently configured optics or may be fully or partially multiplexed.

[0041] In some embodiments, the control and processing system 130 may include an information processing circuit and a light source control circuit. The information processing circuit can be used to process electrical signals to determine information about an object. For example, the information processing circuit includes: an application-specific integrated circuit (ASIC), or a circuit implemented with a programmable logic device (PLD), such as a field-programmable gate array (FPGA), or a microcontroller unit (MCU), or a digital signal processor (DSP), etc. Another example is that the information processing circuit includes a central processing unit (CPU). The light source control circuit can be used to send control signals to the excitation source to control the excitation source to drive the laser to emit light, realizing pulsed laser emission. For example, the light source control circuit can send timing signals to control the laser emission timing. Furthermore, the light source control circuit can control one or more of the pulse interval, pulse intensity, and pulse width. Adding pulse coding functionality can enhance the anti-interference capability of the lidar. The light source control circuit and the information processing circuit can be integrated together. For example, the light source control circuit and the information processing circuit can be integrated into a main control chip, or they can each be independent or partially independent chips. When the lidar 100 includes a scanning system 140, the control and processing system 130 may also include a scanning control circuit for controlling the scanning system. The scanning control circuit can be integrated with one or all of the light source control circuit and the information processing circuit. For example, the scanning control circuit, the light source control circuit, and the information processing circuit can be integrated into a main control chip, or they can each be independent or partially independent chips. In some embodiments, the control and processing system 130 may be implemented in the form of a SOC or an ASIC.

[0042] In some embodiments, the lidar can be installed on a terminal device. The lidar can transmit the detected sensing data to the terminal device. The terminal device can use the sensing data to perform one or more functions such as analysis, decision-making, or control. Terminal devices include, for example, vehicles, ships, aircraft (e.g., flying vehicles, or drones), robots (e.g., industrial robots or home robots).

[0043] Research has found that the ranging capability of lidar is related to the laser's time of flight (TOF). TOF refers to the total time it takes for a laser beam to travel from the emitter, be reflected by the target object, and return to the receiver. By measuring the TOF and combining it with the speed of light, the distance to the object can be calculated. With a fixed horizontal angular resolution and a fixed number of emission channels per horizontal angle, the TOF limit of the emission channel is related to the scanning device's rotation speed: the lower the rotation speed, the longer the allowed TOF time, and the stronger the ranging capability. Most related scanning control schemes adopt a fixed rotation speed design. This approach cannot simultaneously meet the requirements of long-distance detection and scanning efficiency. For example, reducing the rotation speed to improve ranging capability leads to a decrease in the scanning frame rate. Maintaining the frame rate limits the TOF time, making the ranging performance unsuitable for scenarios such as driving.

[0044] Based on this, the present disclosure provides a technical solution to improve ranging capability within at least a portion of the field of view without changing the horizontal resolution and scanning frame rate.

[0045] Figure 2 A schematic diagram of an exemplary lidar structure consistent with some embodiments of this disclosure is shown. For example... Figure 2 As shown, the lidar 200 includes a transmitter 21 and a scanner 22.

[0046] Transmitter 21 can emit probe light.

[0047] The scanner 22 can oscillate around its axis within a oscillation range, deflecting the probe light into the field of view. The oscillation range includes a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region along a first direction. The first direction is perpendicular to the axis of rotation.

[0048] The scanner 22 rotates at a higher speed in the first fixed speed zone than it does in the second fixed speed zone.

[0049] In the first speed transition zone, the rotational speed of the scanner 22 varies with the angle according to a half-cycle cosine function.

[0050] For example, the transmitter 21 can perform the functions of the laser emission system 110 described above, and may include a driving circuit, a laser and an emission optics.

[0051] For example, scanner 22 can perform the functions of the scanning system 140 described above. Scanner 22 has a beam deflection element, such as a reciprocating mirror.

[0052] In the lidar provided in this embodiment, the scanner 22 has a non-constant speed within its swing range. The scanner 22 swings in a first direction perpendicular to the rotation axis. For example, the first direction can be a horizontal scanning direction. The swing range of the scanner 22 is divided into multiple regions in the first direction, such as a first fixed speed region, a first variable speed transition region, and a second fixed speed region.

[0053] For example, the second fixed velocity region can correspond to a region of interest (ROI) within the field of view, such as the central region of the field of view. The first fixed velocity region can correspond to a non-ROI region within the field of view, such as the edge region of the field of view. The scanner 22 can be configured with different rotational speeds in different regions of its swing range. For example, the first direction can correspond to the horizontal field of view of the LiDAR. The central region of the horizontal field of view is typically the ROI region of the vehicle-mounted LiDAR. For ROI regions with high ranging requirements, the scanner 22 can use a lower rotational speed for swinging. Conversely, for non-ROI regions with lower ranging requirements, the scanner 22 can use a higher rotational speed for swinging.

[0054] Without changing the angular resolution and frame rate, the swing time of scanner 22 between two adjacent scanning angles is inversely related to its rotational speed. For example, when scanner 22 swings at a lower rotational speed, the swing time between two adjacent scanning angles is correspondingly longer, providing a longer time of flight (TOF) for detection by a single channel of transmitter 21. A longer TOF allows the detected light to travel a greater distance, improving the ranging capability of the lidar in that area. Configuring a lower rotational speed in the ROI area and a relatively higher rotational speed in the non-ROI area allows for targeted enhancement of the ranging capability in the ROI area without reducing the overall scanning frame rate.

[0055] It should be noted that the rotational speed configuration of the scanner 22 in this embodiment is not limited to the example described above. For example, depending on the application scenario, the ROI region can be located not only at the center of the field of view, but also at the edge of the field of view or any other arbitrary location. Correspondingly, the low-speed region of the scanner 22 can also be set at the position corresponding to the ROI region.

[0056] The first speed transition zone is located between the first fixed speed zone and the second fixed speed zone. In the first speed transition zone, the rotational speed of the scanner 22 changes smoothly from high to low or from low to high. The relationship between the rotational speed and angle in the first speed transition zone adopts a half-cycle cosine function. This ensures the continuity of the scanner 22's rotational speed and acceleration, avoiding noise, vibration, harshness (NVH) problems caused by sudden speed changes, while also guaranteeing the smoothness of the scanning trajectory.

[0057] The following section provides a further explanation of how to control the speed in the first speed change transition zone using a half-cycle cosine function.

[0058] During variable-speed scanning, if the rotational speed or angular velocity of the scanner 22 changes too drastically, it will cause impact and vibration in its internal mechanical components, such as the shaft, bearings, and mirror support structure. This may lead to the aforementioned NVH problems, affecting the motion accuracy and service life of the scanner 22. Therefore, in the first speed transition zone, this embodiment uses a half-cycle cosine function to control the relationship between the scanner 22's rotational speed and angle.

[0059] For example, taking the rotational speed in the first fixed speed zone as greater than that in the second fixed speed zone, and the transition from the first fixed speed zone to the second fixed speed zone via the first speed change transition zone as an example, the change in rotational speed of the scanner 22 with respect to angle can be expressed as follows:

[0060] (Formula 1).

[0061] in, The rotational speed within the first fixed speed range. The rotational speed in the second fixed speed zone. This refers to the angle range corresponding to the first speed change transition zone. This is the starting angle of the first speed change transition zone.

[0062] Taking the derivative of the above formula, we can obtain the acceleration. : (Formula 2).

[0063] From the above formula two, it can be seen that at the beginning of the first gear shift transition zone ( ) and endpoint ( At point (π / 2), sin(0) = sin(π) = 0. At the beginning and end of the first acceleration transition zone, the acceleration... Throughout the entire first gear shift transition zone, acceleration... It changes smoothly with the angle, without any abrupt changes, and satisfies the continuity condition of the second derivative.

[0064] In some embodiments, along the first direction, the swing range further includes a second speed transition zone and a third speed fixed zone. The rotational speed of the scanner in the second speed transition zone varies with the angle according to a half-cycle cosine function.

[0065] Figure 3 A schematic diagram of an exemplary scanning scheme consistent with some embodiments of this disclosure is shown. For example... Figure 3As shown, the swing range of the scanner 22 along the first direction includes a first fixed speed region 31, a first speed change transition region 32, a second fixed speed region 33, a second speed change transition region 34, and a third fixed speed region 35. The second speed change transition region 34 also uses a half-cycle cosine function to ensure the smoothness of speed changes.

[0066] For example, the oscillation range of the scanner 22 can include multiple variable speed transition zones and multiple fixed speed zones. For instance, within a complete oscillation cycle, the scanner 22 can move from a high-speed fixed zone through a variable speed transition zone into a low-speed fixed zone, and then through another variable speed transition zone into another high-speed fixed zone. That is, the scanner 22 oscillates sequentially through a high-speed fixed zone, a variable speed transition zone, a low-speed fixed zone, and a high-speed fixed zone. Figure 3 As shown, the first fixed speed zone 31, the first speed transition zone 32, the second fixed speed zone 33, the second speed transition zone 34, and the third fixed speed zone 35 correspond to the high-speed fixed zone, the speed transition zone, the low-speed fixed zone, the speed transition zone, and the high-speed fixed zone, respectively.

[0067] In other embodiments, depending on the requirements of the scanning scenario, the swing range of the scanner 22 may include more than two speed transition zones and more than three speed fixed zones. No specific limitations are imposed in the embodiments disclosed herein.

[0068] In some embodiments, the rotational speed of the scanner 22 in the third fixed speed zone 35 is the same as the rotational speed of the scanner 22 in the first fixed speed zone 31.

[0069] For example, the scanner 22 can use the same high-speed scanning at both ends of the swing range, such as the left and right edges. The scanner 22 can use a low-speed scanning in the middle region, forming a symmetrical variable speed pattern.

[0070] In some embodiments, along the first direction, the oscillation range further includes a steering transition zone. The rotational speed of the scanner 22 in the steering transition zone varies with the angle according to a half-cycle cosine function.

[0071] For example, the scanner 22 oscillates back and forth around its axis. When the scanner 22 oscillates to the edge region, it needs to decelerate, stop, and accelerate in the opposite direction. This region of deceleration, stopping, and acceleration is referred to as the steering transition zone. By using a half-cycle cosine function to control the rotational speed change in the steering transition zone, it can be ensured that the speed and acceleration of the scanner 22 are continuous during the commutation process, avoiding mechanical shock and vibration.

[0072] In some embodiments, the emission timing of the transmitter 21 is also controlled. Exemplarily, the emission time interval of the transmitter 21 is associated with the velocity partition of the scanner 22. The transmitter 21 employs different emission time intervals within the field of view corresponding to different angular velocities. This allows for a longer time-of-flight (TOF) capability in the low-speed region, enhancing ranging capabilities.

[0073] For example, within a detection window, transmitter 21 emits detection light, and receiver receives the corresponding echo light. The lidar determines detection data based on the detection light and echo light, such as the distance, angle, or reflectivity of an object. The lidar can emit detection light once or multiple times within a detection window. For example, the lidar can have one channel for detection within a detection window, or multiple channels for parallel detection. A channel can include one or more lasers. After completing the emission and reception of light in one detection window, the emission and reception of light in the next detection window begins. The emission and reception processes of two adjacent detection windows do not overlap in time. This avoids crosstalk between echoes from different angles. The emission time interval between non-parallel detection channels determines the maximum time length that a detection window can occupy. The time length of a detection window determines the maximum Time of Flight (TOF) of the detection light. The longer the TOF, the farther the detection light can propagate, and the farther the detection range of the lidar. The emission time interval is positively correlated with the maximum detection range of the lidar.

[0074] Some embodiments of this disclosure configure different transmission time intervals for different field-of-view angles, which can achieve differentiated control of the farthest detection distance.

[0075] In some embodiments, the field of view along the first direction includes a first angular range 36 corresponding to the first fixed speed region 31, a second angular range 37 corresponding to the first variable speed transition region 32, and a third angular range 38 corresponding to the second fixed speed region 33. The transmitter 21 can emit multiple probe beams in a preset emission sequence. The emission time interval of the transmitter 21 in the first angular range 36 is shorter than the emission time interval of the transmitter 21 in the third angular range 38.

[0076] For example, the rotational speed of the first fixed speed zone 31 is greater than that of the second fixed speed zone 33. The transition from the first fixed speed zone 31 to the second fixed speed zone 33 occurs via a first variable speed transition zone 32. The field of view is divided into multiple angular ranges corresponding to different speed zones along the first direction. In the first angular range 36 corresponding to the first fixed speed zone 31, the transmitter 21 uses a shorter transmission time interval. In the third angular range 38 corresponding to the second fixed speed zone 33, the transmitter 21 uses a longer transmission time interval. Increasing the transmission time interval improves the ranging capability of the lidar. In the second angular range 37 corresponding to the first variable speed transition zone 32, the transmission time interval smoothly transitions between short and long transmission time intervals.

[0077] LiDAR employs short transmission intervals in high-speed fixed areas and long transmission intervals in low-speed fixed areas, allowing for efficient allocation of limited time resources without altering the scanning frame rate. For example, a longer transmission interval in low-speed fixed areas increases the maximum detection range and enhances ranging capabilities. Conversely, a shorter transmission interval in high-speed fixed areas ensures overall scanning efficiency remains unaffected. A smooth transition in transmission intervals within variable speed zones improves the uniformity of the point cloud.

[0078] In some embodiments, the second angle range 37 includes a plurality of horizontal scanning angles in the direction from the first angle range 36 to the third angle range 38. The transmission time interval of the transmitter 21 at the plurality of horizontal scanning angles increases progressively. In this way, the point cloud density of the lidar can be kept uniform within the field of view.

[0079] In some embodiments, the second angle range 37 includes a plurality of sequentially arranged second angle sub-ranges along the first direction. In the direction from the first angle range 36 to the third angle range 38, the transmission time interval of the transmitter 21 in the plurality of second angle sub-ranges increases. In the direction from the third angle range 38 to the first angle range 36, the transmission time interval of the transmitter 21 in the plurality of second angle sub-ranges decreases.

[0080] For example, as the scanner 22 swings from a high-speed region to a low-speed region, the transmission time interval of the transmitter 21 gradually increases according to the divided angular sub-ranges. The allowed time of flight gradually transitions from short TOF to long TOF. Correspondingly, as the scanner 22 swings from a low-speed region to a high-speed region, the transmission time interval of the transmitter 21 gradually decreases according to the divided angular sub-ranges, and the allowed time of flight gradually transitions from long TOF to short TOF. This configuration, where the transmission time interval varies with the scanner speed, allows for uniform point cloud density across the entire field of view and simplifies the control logic. The increment or decrement step sizes for adjacent angular sub-ranges can be the same or different.

[0081] like Figure 3 As shown, there is a correspondence between the field of view (FOV) partitions and the speed partitions of the scanner 22. Along the horizontal scanning direction, the FOV sequentially includes: a first angular range 36 corresponding to the first fixed speed zone 31, a second angular range 37 corresponding to the first variable speed transition zone 32, a third angular range 38 corresponding to the second fixed speed zone 33, a fourth angular range 39 corresponding to the second variable speed transition zone 34, and a fifth angular range 40 corresponding to the third fixed speed zone 35. For example, the scanner 22 rotates at the same speed in the first fixed speed zone 31 and the third fixed speed zone 35. The scanner 22 rotates at a higher speed in the first fixed speed zone 31 and the third fixed speed zone 35 than it does in the second fixed speed zone 33. The first angular range 36 can be a short TOF zone. The second angular range 37 can be a variable TOF zone transitioning from short TOF to long TOF. The third angular range 38 can be a long TOF zone. The fourth angular range 39 can be a variable TOF zone transitioning from long TOF to short TOF. The fifth angular range 40 can be a short TOF zone.

[0082] Taking the scanner 22, which includes a swing mirror, as an example, the swing mirror includes a reflector. When the reflector reflects two probe beams with a time interval, the angle between the reflected beams is twice the swing angle of the swing mirror. Based on this, Figure 2 The field of view range shown in the diagram is twice the swing angle range of the corresponding mirror speed zone.

[0083] Within the FOV angle range corresponding to the variable speed zone, the transmission time interval or allowed Time of Flight (TOF) transitions smoothly. For example, when the scanner 22 transitions from the fast speed zone to the slow speed zone, the transmission time interval of the transmitter 21 gradually increases according to a preset range of angle sub-ranges, and the allowed TOF gradually transitions from short TOF to long TOF. When the scanner 22 swings from the slow speed zone to the fast speed zone, the transmission time interval of the transmitter 21 gradually decreases, and the allowed TOF gradually transitions from long TOF to short TOF. This step-by-step switching avoids abrupt changes in the transmission time interval, ensuring a smooth transition of point cloud density within the FOV.

[0084] The transmitter uses different emission time intervals in different field-of-view zones. This results in differences in the ranging capability of the lidar in each region. For example, the ranging capability is enhanced in the long TOF region, and relatively weaker in the short TOF region. As mentioned earlier, embodiments of this disclosure, through the configuration of variable-speed mirrors and corresponding emission timing, can form ROI regions and non-ROI regions with different ranging capabilities within the field of view. ROI regions correspond to long TOF regions and have stronger ranging capabilities. Non-ROI regions correspond to short TOF regions and have relatively weaker ranging capabilities. This configuration is particularly suitable for forward-facing lidar applications. Forward-facing lidar requires high ranging capability in the central region of the field of view. Configuring the central region of the field of view as the ROI region can meet the needs of forward-facing lidar for long-range detection in the central region of the field of view. Embodiments of this disclosure enable the lidar to exhibit differences in the maximum detectable distance for different regions within the same frame point cloud. Figure 4 As shown, Figure 4 An exemplary probe contour diagram consistent with some embodiments of this disclosure is shown. For example... Figure 4 As shown in (a), under the scheme where the scanner 22 rotates at a constant speed and the emission time interval is uniform, the distance between the farthest detection points of the lidar is equal throughout the entire field of view. Figure 4 (a) is represented by equidistant circular arc-shaped detection profiles. For example... Figure 4 As shown in (b), in the variable speed scanning scheme combined with the variable emission time interval provided in this embodiment, the scanner 22 swings at a lower rotational speed in the ROI region and is coupled with a longer emission time interval, so that the maximum detection distance of the lidar in the ROI region is greater than the maximum detection distance in the edge region. Figure 4 (b) is represented by an elliptical arc-shaped detection profile. The direction corresponding to the ROI is the direction of the major axis of the ellipse.

[0085] For example, the transmission time intervals corresponding to the different angle ranges mentioned above, and the step size for changing the transmission time interval in the speed transition zone, can be pre-configured. Alternatively, they can be dynamically adjusted according to the needs of the current scenario. This disclosure does not impose any limitations.

[0086] For example, the swing angle range corresponding to at least one of the first and second speed change transition regions can be configured to a small angle range, such as less than or equal to an angle threshold. This swing angle range can be set according to the balance requirements between scanning efficiency and speed change smoothness. The angle threshold is no greater than 10 degrees. The angle threshold is, for example, but not limited to, 5 degrees, 6 degrees, 8 degrees, or 10 degrees. In some embodiments, the swing angle range corresponding to at least one of the first and second speed change transition regions can be set to be less than or equal to 5 degrees. This angle range design of the speed change transition regions allows for a balance between scanning efficiency and speed change smoothness.

[0087] In the aforementioned embodiments, the variable speed control of the scanner 22 enables differentiated ranging capabilities for different areas in the first direction, such as the horizontal direction. In the second direction, such as the vertical direction, there may also be differences in ranging requirements. For example, in a vehicle driving scenario, a longer detection distance is needed for the area directly in front of the vehicle, while the ranging capability requirements are relatively lower for edge areas near the sky or ground.

[0088] This disclosure discloses embodiments that differentiate the emission time interval of the transmitter 21 in a second direction. In some embodiments, the transmitter 21 includes a plurality of lasers. Within a field of view corresponding to the same fixed velocity region, the emission time interval of the plurality of lasers is associated with the field of view angle of the second direction corresponding to the plurality of lasers. The second direction is perpendicular to the first direction.

[0089] For example, within the same fixed velocity region, the multiple lasers of transmitter 21 can employ various emission time intervals, which can be differentiated based on the corresponding field-of-view position of each laser in the second direction. For instance, in the second direction, lasers whose corresponding field-of-view positions are closer to the center of the field of view have longer emission time intervals, while lasers whose corresponding field-of-view positions are closer to the edge of the field of view have shorter emission time intervals.

[0090] The emission time interval of the plurality of lasers is associated with the field of view in the second direction corresponding to the plurality of lasers. In some embodiments, the emission time interval of the plurality of lasers is inversely correlated with the field of view in the second direction corresponding to the plurality of lasers. Alternatively, in some embodiments, the plurality of lasers comprises a plurality of laser groups. The emission time intervals of different laser groups are different. The emission time interval of the laser group with a large field of view in the second direction is smaller than the emission time interval of the laser group with a small field of view in the second direction.

[0091] For example, the larger the field of view angle in the second direction, the farther the region corresponding to that field of view angle is from the center line of the field of view in the second direction, and the shorter the emission time interval of the laser. Conversely, the smaller the field of view angle in the second direction, the closer the region is to the center line of the field of view in the second direction, and the longer the emission time interval of the laser.

[0092] For another example, the lasers arranged in the second direction can be divided into several groups. Each group contains multiple lasers. An emission time interval can be set for each group of lasers. Different groups can contain the same or different numbers of lasers. For example, 128 lasers in the second direction can be divided into 16 groups of 8 each. Alternatively, the central region group may contain more lasers, while the edge region group may contain fewer. In practical applications, this can be set according to the differentiated requirements of ranging capabilities. The emission time interval of laser groups with a large field of view in the second direction, such as the edge region group, can be shorter than that of laser groups with a small field of view in the second direction, such as the central region group. This grouping method simplifies the control logic while achieving differentiated ranging capabilities in the second direction. Taking the second direction as a vertical direction as an example, when scanning edge areas near the sky or ground, the laser group uses a shorter emission time interval, allowing for a shorter TOF (Time of Flight). When scanning the central region close to the front, the laser array uses a longer emission time interval, allowing for a longer TOF.

[0093] The above implementation method enhances the ranging capability of the central region in the second direction.

[0094] like Figure 5 As shown, Figure 5 A schematic diagram of an exemplary scanner 22 consistent with some embodiments of this disclosure is shown, including a reflector 221 and a drive device 222.

[0095] The driving device 222 can drive the reflector 221 to oscillate around the axis within an oscillation range. The oscillation range includes a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region along a first direction. The first direction is perpendicular to the axis of rotation. The rotational speed of the reflector 221 in the first fixed-speed region is greater than its rotational speed in the second fixed-speed region. In the first variable-speed transition region, the rotational speed of the reflector 221 varies with the angle according to a half-period cosine function.

[0096] For example, along the first direction, the swing range further includes a second speed-changing transition zone and a third speed-fixed zone. The rotational speed of the reflector 221 in the second speed-changing transition zone varies with the angle according to a half-period cosine function.

[0097] For example, the rotational speed of the reflector 221 in the third fixed speed zone is the same as the rotational speed in the first fixed speed zone.

[0098] For a detailed description of the scanner 22 provided in this embodiment, please refer to the relevant description of the scanner 22 in the foregoing lidar embodiments. For example, the partitioning of the scanner 22 within its swing range, the rotational speed relationship between each partition, and the half-cycle cosine function control method of the rotational speed with respect to the angle in the speed transition zone, etc., can be found in the corresponding description of the scanner 22 in the foregoing lidar embodiments.

[0099] In addition, some embodiments of this disclosure also provide an exemplary lidar, including a scanner and a transmitter.

[0100] The scanner can oscillate around its axis within a oscillation range, deflecting the probe light into the field of view. The oscillation range, along a first direction, includes a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region. The field of view, along the first direction, includes a first angular range corresponding to the first fixed-speed region, a second angular range corresponding to the first variable-speed transition region, and a third angular range corresponding to the second fixed-speed region. The first direction is perpendicular to the scanner's axis of rotation. The transmitter can emit multiple probe beams according to a preset emission sequence. The emission time interval of the transmitter in the first angular range is shorter than the emission time interval of the transmitter in the third angular range.

[0101] The second angular range includes a plurality of sequentially arranged second angular sub-ranges along the first direction. In the direction from the first angular range to the third angular range, the transmission time interval of the transmitter in the plurality of second angular sub-ranges increases. In the direction from the third angular range to the first angular range, the transmission time interval of the transmitter in the plurality of second angular sub-ranges decreases.

[0102] For example, the emission timing control scheme adopted by the transmitter in this embodiment of the present disclosure cooperates with the variable speed oscillation scheme of the scanner. For instance, within a first angular range corresponding to a first fixed speed zone where the scanner oscillates at a higher rotational speed, the transmitter uses a shorter emission time interval. Within a third angular range corresponding to a second fixed speed zone where the scanner oscillates at a lower rotational speed, the transmitter uses a longer emission time interval. When the scanner is in the variable speed transition zone, the emission time interval of the transmitter also smoothly transitions within the second angular range. Through this coordinated control of the scanner rotational speed and the transmitter emission timing, a targeted enhancement of the ranging capability of the region of interest can be achieved without changing the horizontal resolution and scanning frame rate. Other parts not detailed in this embodiment of the present disclosure can be found in the corresponding descriptions in the foregoing lidar embodiments.

[0103] This disclosure also provides an apparatus, which may include, for example, a vehicle, an intelligent robot, or any other device that applies LiDAR. The apparatus may include the LiDAR as described in any of the foregoing embodiments, or the scanner as described in any of the foregoing embodiments.

[0104] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not described in detail or in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Furthermore, the above embodiments can be freely combined as needed.

Claims

1. A lidar, comprising: The application comprises: a transmitter configured to emit probe light; a scanner configured to oscillate around an axis of rotation within an oscillation range, deflecting the probe light into a field of view range, the oscillation range comprising a first speed-fixed region, a first variable-speed transition region, and a second speed-fixed region along a first direction, the first direction being perpendicular to the axis of rotation; the rotation speed of the scanner in the first speed-fixed region is greater than the rotation speed of the scanner in the second speed-fixed region; in the first variable-speed transition region, the rotation speed of the scanner changes with the angle in a half-cycle cosine function.

2. The lidar of claim 1, wherein, Along the first direction, the oscillation range further comprises a second variable-speed transition region and a third speed-fixed region, the rotation speed of the scanner in the second variable-speed transition region changes with the angle in a half-cycle cosine function.

3. The lidar of claim 2, wherein, The rotation speed of the scanner in the third speed-fixed region is the same as the rotation speed of the scanner in the first speed-fixed region.

4. The lidar of claim 1, wherein, Along the first direction, the oscillation range further comprises a turning transition region; the rotation speed of the scanner in the turning transition region changes with the angle in a half-cycle cosine function.

5. The lidar of claim 1, wherein, The field of view range along the first direction comprises a first angle range corresponding to the first speed-fixed region, a second angle range corresponding to the first variable-speed transition region, and a third angle range corresponding to the second speed-fixed region; the transmitter is further configured to emit a plurality of probe light beams in a preset light-emitting timing, the emission time interval of the transmitter in the first angle range is less than the emission time interval of the transmitter in the third angle range.

6. The lidar of claim 5, wherein, The second angle range along the first direction comprises a plurality of second angle sub-ranges arranged in sequence; in the direction from the first angle range to the third angle range, the emission time interval of the transmitter in the plurality of second angle sub-ranges increases; in the direction from the third angle range to the first angle range, the emission time interval of the transmitter in the plurality of second angle sub-ranges decreases.

7. The lidar of claim 2, wherein: at least one of the first variable-speed transition region and the second variable-speed transition region corresponds to an oscillation angle range less than or equal to 5 degrees.

8. The lidar of claim 1, wherein, The transmitter comprises a plurality of lasers; In the field of view range corresponding to the same speed-fixed region, the emission time interval of the plurality of lasers is associated with the field of view angle of the second direction corresponding to the plurality of lasers, the second direction being perpendicular to the first direction.

9. The lidar of claim 8, wherein, The association between the emission time interval of the plurality of lasers and the field of view angle of the second direction corresponding to the plurality of lasers comprises: The emission time interval of the plurality of lasers is inversely related to the field of view angle of the second direction corresponding to the plurality of lasers, or the plurality of lasers comprises a plurality of laser groups, the emission time intervals of different laser groups are different, and the emission time interval of the laser group with a larger field of view angle of the second direction is less than the emission time interval of the laser group with a smaller field of view angle of the second direction.

10. A scanner for a lidar, characterized by, The application comprises: a mirror; A driving device is configured to drive the reflector to oscillate around a rotation axis within an oscillation range; the oscillation range includes a first fixed speed region, a first variable speed transition region, and a second fixed speed region along a first direction, the first direction being perpendicular to the rotation axis; The rotational speed of the reflector in the first fixed speed region is greater than its rotational speed in the second fixed speed region; In the first speed transition zone, the rotational speed of the reflector changes with the angle in a manner that satisfies a half-cycle cosine function.

11. A lidar, comprising: include: A scanner is configured to oscillate around a pivot within a oscillation range to deflect the probe light into a field of view. The oscillation range includes, along a first direction, a first fixed-speed region, a first variable-speed transition region, and a second fixed-speed region. The field of view includes, along the first direction, a first angular range corresponding to the first fixed-speed region, a second angular range corresponding to the first variable-speed transition region, and a third angular range corresponding to the second fixed-speed region. The first direction is perpendicular to the pivot of the scanner. The transmitter is configured to emit multiple beams of probe light according to a preset emission sequence; the emission time interval of the transmitter in the first angular range is less than the emission time interval of the transmitter in the third angular range; The second angle range includes a plurality of second angle sub-ranges arranged sequentially along the first direction; in the direction from the first angle range to the third angle range, the transmission time interval of the transmitter in the plurality of second angle sub-ranges increases.

12. An apparatus, comprising: It includes the lidar as described in any one of claims 1 to 9, or the scanner as described in claim 10, or the lidar as described in claim 11.

Images