Laser radar detection method and laser radar

Abstract

The present application is applicable to the field of laser radar technology, and provides a laser radar detection method and a laser radar. The laser radar includes a transmitter and a collector, as well as a control and processing circuit connected to the transmitter and the collector; the transmitter is used to transmit a pulse beam to the target detection area, and the target detection area includes multiple sub-areas; the collector is used to collect the pulse beam reflected by the target in the target detection area; the control and processing circuit is used to synchronously control the transmitter and the collector, and calculate the flight time of the pulse beam from emission to collection by the collector to obtain the distance of the target, wherein the transmitter is configured to transmit at least partially different pulse beams to each of the multiple sub-areas, so that the laser radar has different detection capabilities and detection accuracy for different sub-areas. The embodiments of the present application can realize partitioned detection and improve the scene adaptability of radar detection.

Description

Technical Field

[0001] The present application belongs to the field of laser radar technology, and in particular relates to a laser radar detection method and a laser radar. Background Art

[0002] Modern vehicles (such as cars, trucks, and motorcycles) often include multiple systems, such as autonomous driving systems and advanced driver assistance systems (ADAS). These systems provide information to the driver or operator and can semi- or fully automatically control the vehicle to perform various functions. Driver assistance systems use sensors to collect environmental data around the vehicle, generate a model of the environment, and respond to changes in the environment based on this data. The development of high-precision sensors continues to advance the application of driver assistance systems.

[0003] LiDAR (LiDAR) is a key sensor for collecting environmental data in systems such as autonomous driving and driver assistance systems. It works by emitting a pulsed light beam and detecting the reflected light signal. The time of flight between the pulsed light beam's emission and its detection is then calculated to determine the target's distance. In practical applications, when using LiDAR to detect objects, the objects often appear in a specific area within the LiDAR's detection zone. The LiDAR's detection zone typically fully covers the area where the object typically appears. However, if an object only appears partially within the detection zone, the light signal projected into other areas where the object is absent is wasted. For example, when a LiDAR is placed at the front of a vehicle to detect obstacles ahead, the obstacles appear only on the ground, while the pulsed light beam projected high into the sky is largely wasted. Furthermore, objects come in many different types, and their reflectivity varies, reflecting different light signals. To ensure detection accuracy, the intensity of the transmitted light beam needs to be increased for objects with low reflectivity, while it can be reduced for objects with high reflectivity. Therefore, a rational design of the detection method is necessary to address the aforementioned technical issues. Summary of the Invention

[0004] The embodiments of the present application provide a laser radar detection method and a laser radar, which can improve the scene adaptability of laser radar detection.

[0005] According to a first aspect of an embodiment of the present application, there is provided a laser radar, comprising a transmitter, a collector, and a control and processing circuit respectively connected to the transmitter and the collector; the transmitter is used to transmit a pulse light beam to a target detection area, the target detection area comprising a plurality of sub-areas; the collector is used to collect the pulse light beam reflected by a target in the target detection area; the control and processing circuit is used to synchronously control the transmitter and the collector, and calculate the flight time of the pulse light beam from emission to collection by the collector to obtain the distance of the target; wherein the transmitter is configured to transmit at least partially different pulse light beams to each of the plurality of sub-areas, so that the laser radar has different ranging capabilities and detection accuracy for different sub-areas.

[0006] In some embodiments, the emitter includes a light source array, the pulsed light beams emitted by the light source array are symmetrically distributed along the main optical axis of the laser radar, and the area of the light source array is configured so that the emission field of view corresponding to the pulsed light beams emitted by the light source array covers the target detection area. The control and processing circuit is used to control the emitter to emit the pulsed light beam to the target sub-area among the multiple sub-areas; alternatively, the control and processing circuit is used to control the emitter to emit the pulsed light beam to each of the sub-areas, and configure the laser parameters of the pulsed light beam emitted to the target sub-area to be different from the laser parameters of the pulsed light beam emitted to the non-target sub-areas among the multiple sub-areas.

[0007] In some embodiments, the main optical axis of the laser radar is configured to be tilted relative to the mounting plane so that the detection field of view of the laser radar is offset along a preset direction within the target detection area, so that the detection field of view is adapted to the target sub-area within the multiple sub-areas. The control and processing circuit is further configured to control the emitter to emit a pulsed light beam toward the target detection area, thereby adjusting the laser parameters of the pulsed light beam emitted to the central area of the target detection area to compensate for ranging performance, wherein the central area corresponds to one or more of the sub-areas.

[0008] In some embodiments, the transmitter includes an emitting optical element and a light source array; the image height of the emitting optical element is configured so that the theoretical detection area of the lidar covers the target detection area; the center of the light source array is configured to be offset from the main optical axis of the emitting optical element so that the pulse light beam emitted by the light source array is projected onto part of the sub-area in the target detection area.

[0009] In some embodiments, the multiple sub-regions are distributed non-overlappingly along a preset direction, the emitter includes a light source array, and the light source array includes a sub-light source array corresponding one-to-one to each sub-region of the multiple sub-regions; the control and processing circuit is used to control each of the sub-light source arrays to emit a pulse light beam to the corresponding sub-region, wherein the laser parameters of the pulse light beams emitted by at least some of the sub-light source arrays are different.

[0010] In some embodiments, the target detection area includes multiple detection unit areas, each of which includes at least one detection unit area; the emitter includes a light source array, each of which includes a sub-light source array corresponding to each detection unit area; the control and processing circuit controls the sub-light source arrays corresponding to all detection unit areas contained in the sub-area to be simultaneously activated, and configures the laser parameters of the laser pulses emitted by all sub-light source arrays corresponding to each sub-area to be the same. The control and processing circuit is further configured to determine the target sub-area where the target will be located at the next detection moment based on the sub-area where the target is currently located, and control the emitter to emit a pulsed light beam to the target sub-area where the target is located at the next detection moment.

[0011] A second aspect of an embodiment of the present application provides a laser radar detection method, including: emitting a pulse light beam to a target detection area, the target detection area including multiple sub-areas, and the pulse light beam emitted to each sub-area of the multiple sub-areas is at least partially different; collecting the pulse light beam reflected by the target in the target detection area; calculating the flight time of the pulse light beam from emission to collection to obtain the distance of the target, so that the laser radar has different detection accuracy for different sub-areas.

[0012] In an embodiment of the present application, a pulse light beam is emitted to a target detection area, and then the pulse light beam reflected by the target in the target detection area is collected, and the flight time of the pulse light beam from emission to collection by the collector is calculated to obtain the distance of the target, wherein the pulse light beam emitted by the transmitter to each sub-area in the target detection area is at least partially different, thereby enabling partitioned detection, and detecting areas of interest and areas of non-interest with different detection accuracies, or detecting different areas with different detection accuracies based on reflectivity requirements, or, based on different ranging requirements for the central field of view and the edge field of view, detecting the sub-area corresponding to the central duration and the sub-area corresponding to the edge field of view with different detection accuracies, thereby improving the scene adaptability of radar detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0014] Figure 1 This is a schematic structural diagram of a laser radar provided in an embodiment of the present application;

[0015] Figure 2 This is a schematic diagram of the detection of the laser radar provided in the embodiment of the present application Figure 1 ;

[0016] Figure 3 This is a schematic diagram of the detection of the laser radar provided in the embodiment of the present application Figure 2 ;

[0017] Figure 4 This is a schematic diagram of the detection of the laser radar provided in the embodiment of the present application Figure 3 ;

[0018] Figure 5a and Figure 5b They are schematic diagrams of the division of target detection areas.

[0019] Among them, the reference numerals in the figures are: 1-laser radar; 11-emitter; 12-collector; 110-light source array; 120-pixel array. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of this application more clear, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without making any creative work are protected by this application.

[0021] LiDAR is an important sensor for collecting environmental data in systems such as autonomous driving systems and driver assistance systems. Its principle is to calculate the distance to the target by calculating the flight time of the pulse beam from emission to collection by emitting a pulse light beam and detecting the reflected light signal.

[0022] In practical applications, when using lidar to detect objects, the area within the target detection area where the object appears is often fixed. The lidar emits light signals to the target detection area to detect the object. However, if the object only appears in part of the target detection area, the light signals projected to other areas where the object does not exist are wasted. For example, when a lidar is placed at the front of a vehicle to detect obstacles in front of the vehicle, the obstacles will only appear on the ground and are generally concentrated in the range relative to the main optical axis of the lidar or below the main optical axis. The pulse beams emitted high into the sky are largely wasted. For example, the vertical field of view of the lidar transmitter and collector is configured to be -20° to +20°, with 0° being the main optical axis of the lidar. However, in actual measurements, the targets are concentrated in the range of -30° to +10°. Therefore, it will be difficult to detect objects within the range of -20° to -30°, and the pulse beams emitted between +10° and +20° are actually wasted. On the other hand, a wide variety of objects have varying reflectivities, requiring different pulsed beams. Low-reflectivity objects require a higher intensity, while high-reflectivity objects can be reduced. Therefore, a rational design of the detection method is necessary to address these technical issues.

[0023] In order to illustrate the technical solution of the present application, specific embodiments are provided below.

[0024] Figure 1 A schematic diagram of the laser radar 1 provided in the present application is shown. The laser radar 1, also known as a distance measurement system, includes a transmitter 11, a collector 12, and a control and processing circuit (not shown). The transmitter 11 includes a light source array 110 composed of one or more light-emitting elements (such as lasers), which is used to emit a pulse light beam to the target detection area, and at least part of the pulse light beam is reflected by the target to form a reflected light beam that is incident on the collector 12. The collector 12 may include a pixel array 120 composed of a plurality of pixels, which is used to collect the pulse light beam reflected by the target in the target detection area, so as to process the reflected light signal and output a photon signal. The control and processing circuit can synchronously control the transmitter 11 and the collector 12 through a trigger signal, process the photon signal, and calculate the flight time of the pulse light beam from emission to collection to obtain the distance of the target.

[0025] In a specific embodiment of the present application, the transmitter 11 may include an emitting chip, an emitting optical element, and a driver, etc. The emitting chip may be a vertical cavity surface emitting laser (VCSEL) array light source chip. In one embodiment, the light source array 110 is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate. Among them, the light source array 110 can emit a pulsed light beam outward at a certain frequency (pulse period) under the control of the control and processing circuit, and the pulsed light beam is projected into the detection field of view through the emitting optical element to form an illumination spot, wherein the frequency can be set according to the measurement distance. The emitting optical element may be one or more lenses, diffractive optical elements (DOE), reflectors, galvanometers, microlens arrays and other elements.

[0026] The collector 12 may include a receiving chip, and preferably, the receiving chip may be a pixel array 120. The collector 12 also includes a filtering unit and a receiving optical element. The light beam incident on the collector 12 is imaged on the pixel array 120 through the filtering unit and the receiving optical element. The pixel array 120 may include a plurality of pixels that collect photons, and each pixel may be one of single-photon devices that collect photons, such as an avalanche photodiode (APD), a single-photon avalanche diode (SPAD), and a silicon photomultiplier (SiPM). The situation in which the pixel array 120 collects photons is regarded as a photon detection event and outputs a photon signal. In some embodiments of the present application, the pixel array 120 is composed of a plurality of SPADs, which can respond to a single incident photon and output a photon signal indicating the corresponding arrival time of the received photon at each SPAD. Generally, the laser radar 1 may also include a readout circuit (not shown) composed of one or more components such as a signal amplifier, a time-to-digital converter (TDC), and an analog-to-digital converter (ADC) connected to the pixel array 120. The readout circuit can be integrated with the pixels as part of the collector 12, or it can be part of the control and processing circuit. For ease of explanation, the readout circuit is uniformly referred to as part of the control and processing circuit below.

[0027] In some embodiments of the present application, the readout circuit may include a TDC circuit and a histogram circuit. Specifically, the TDC circuit is used to record the flight time of the photon from emission to collection and generate a time signal (e.g., a time code). The time signal is input into the histogram circuit to find the corresponding storage unit (time bin) in the histogram circuit and increase the photon count value in the time bin by 1. After repeatedly emitting multiple pulse beams to the target point (number of pulses), the time signals detected multiple times are input into the corresponding time bins of the histogram circuit and stored so that the histogram circuit generates a histogram containing the flight time corresponding to the pulses.

[0028] Accordingly, the control and processing circuitry can receive the aforementioned histogram and perform filtering, interpolation, and other processing on the histogram to calculate the flight time of the pulsed light beam from emission to acquisition, and further calculate the target's distance information. Methods for calculating flight time based on the histogram include peak-finding and centroid methods. The distance d between the target and the ranging system can be estimated as d = (c × Δt) / 2, where c represents the speed of light and Δt is the flight time.

[0029] In some embodiments of the present application, the light source array 110 and the pixel array 120 are disposed in the active regions of the transmitting chip and the receiving chip, respectively, which are disposed at the focal points of the transmitting optical element and the receiving optical element, respectively. The pulsed light beam emitted by the light source array 110 is projected onto the target detection area through the transmitting optical element. The light beam reflected by the target in the target detection area is imaged onto the pixel array 120 through the receiving optical element.

[0030] It should be understood that the light source array 110 may include multiple light-emitting elements, and the pulse light beam emitted by each light-emitting element can be projected to a specified spatial angle of the target detection area, and after reflection, it is imaged onto the corresponding pixel on the pixel array 120 to form a detection channel. The optical elements and pixels that measure the same spatial angle are set corresponding to each other. For example, a light-emitting element and a pixel are set correspondingly to jointly measure a spatial angle of the spatial area. Of course, since the spot size of the light beam emitted by the light-emitting element and projected into the field of view is often larger than the size of the pixel, a light-emitting element can also be configured to correspond to multiple pixels, for example, 4 pixels. In this case, the multiple pixels corresponding to one light-emitting element constitute a "macro pixel".

[0031] In order to improve the environmental adaptability of the laser radar 1, the present application proposes a laser radar 1 that can realize partitioned detection of the laser radar 1.

[0032] Specifically, the transmitter 11 of the laser radar 1 can emit a pulsed light beam toward the target detection area. The spatial region corresponding to the target detection area is a two-dimensional region. The target detection area is symmetrically distributed along the main optical axis of the laser radar 1 and covers a field of view that includes the detection field of view of the laser radar 1. The light beam emitted along the main optical axis of the laser radar 1 is projected onto the center of the target detection area. The detection field of view of the laser radar 1 is the projected field of view of the transmitter, that is, the actual detection area of the laser radar 1, which can be part or all of the target detection area. For example, when the vertical field of view angle corresponding to the region of interest (the target appearance area in the target detection area) is -30° to +10°, the vertical field of view angle corresponding to the target detection area can be -30° to +30° (with the main optical axis at 0°) or a larger range including -30° to +30°, while the vertical field of view angle corresponding to the detection field of view can be -30° to +30°, -30° to +10°, or other ranges including -30° to +10°. In some specific embodiments, the target detection area can be determined based on the vertical field of view corresponding to the region of interest. For example, when the vertical field of view corresponding to the region of interest is -30° to +10°, the vertical field of view of the target on the side farther from the optical axis (0°) is -30°, then -30° to +30° can be used as the target detection area. In some specific embodiments, the target detection area is divided into multiple sub-areas, and each sub-area can be divided into a target sub-area and a non-target sub-area according to the region of interest. For example, when the vertical field of view corresponding to the region of interest is -30° to +10°, all sub-areas within the range are target sub-areas, and the detection field of view of the configured laser radar corresponds to the target sub-area.

[0033] Thus, the pulse beam emitted by emitter 11 to each sub-area within the target detection area is configured to be at least partially different; collector 12 can collect the pulse beam reflected by the target within the target detection area; the control and processing circuit can synchronously control emitter 11 and collector 12 via a trigger signal, and calculate the flight time of the pulse beam from emission to collection based on the output photon signal to obtain the distance to the target. Because the pulse beam emitted by emitter 11 to each sub-area is at least partially different, the laser radar 1 has different ranging capabilities and detection accuracy for different sub-areas.

[0034] That is to say, when the laser radar 1 detects different sub-areas, the pulse light beams used can be the same or different to achieve partitioned detection, and different detection accuracies can be performed on the area of interest and the area of non-interest, or different detection accuracies can be performed on different areas based on the reflectivity requirements, or different detection accuracies can be performed on the sub-area corresponding to the central field of view and the sub-area corresponding to the edge field of view based on the different ranging requirements for the central field of view and the edge field of view, thereby improving the scene adaptability of radar detection.

[0035] In some embodiments, factors affecting the detection accuracy of the laser radar include, but are not limited to, the laser power, number of pulses, pulse frequency, and pulses of different frequencies configured when emitting laser pulses. In order to improve the detection accuracy of the laser radar, the laser power of the emitted pulses can be increased; or the number of pulses can be increased. According to the detection principle of the laser radar, the more pulses there are, the higher the detection accuracy; or the pulse emission frequency can be increased; or pulses with different frequencies can be emitted to select a multi-frequency ranging solution method, etc. The above laser parameter configurations can be selected from one or a combination of multiple ones. This is not specifically limited in this application and can be specifically designed according to the specific situation.

[0036] The following describes the specific implementation of the partition detection method of this application with a specific embodiment.

[0037] Example 1:

[0038] Please refer to Figure 2 In some embodiments of the present application, the pulse light beams emitted by the light source array 110 are symmetrically distributed along the main optical axis direction of the laser radar 1. At this time, the area of the light source array 110 can be configured to increase so that the emission field of view corresponding to the pulse light beams emitted by the light source array 110 covers the target detection area. Specifically, the area of the light source array 110 can be continuously increased by simulation until the emission field of view corresponding to the pulse light beams emitted by the light source array 110 can cover the target detection area. For example, when the vertical field of view angle of the area of interest is -30° to +10°, the target detection area is defined as -30° to +30°. By configuring the area of the light source array, the emission field of view of the pulse light beam is increased, thereby increasing the detection field of view of the laser radar 1, so that the vertical field of view angle corresponding to the detection field of view of the laser radar 1 is increased to -30° to +30°, that is, the actual detection range of the radar covers the target detection area.

[0039] Accordingly, since the region of interest is only a portion of the target detection area, the target detection area is divided into multiple sub-areas. The sub-areas corresponding to the region of interest are defined as target sub-areas, and the sub-areas corresponding to the non-region of interest are defined as non-target sub-areas. The control and processing circuit can only control the emitter 11 to emit pulsed light beams to the multiple sub-areas corresponding to the region of interest, that is, only control some light sources in the light source array to emit pulsed light beams to the target sub-areas; or, when controlling the emitter to emit a pulsed light beam to each sub-area, configure the laser parameters of the pulsed light beam emitted to the target sub-area to be different from the laser parameters of the pulsed light beam emitted to the non-target sub-area. The laser parameters of the emitted pulsed light beam include one or more of the following: laser power, number of pulses, pulse frequency, pulse type, etc.

[0040] Specifically, the control and processing circuit can send a first modulation signal to the transmitter 11. The first modulation signal can be used to regulate the laser power of the pulsed light beam emitted by the optical element corresponding to the target sub-area and / or the non-target sub-area, so that the light intensity of the pulsed light beam emitted to the target sub-area is higher, or the light intensity of the pulsed light beam emitted to the non-target sub-area is lower. It can also be used to regulate the optical element corresponding to the target sub-area to emit light and the optical element corresponding to the non-target sub-area not to emit light, thereby improving the detection accuracy of the laser radar 1 for the area of interest. For example, after the vertical field of view angle of the laser radar 1 is increased to -30° to +30°, the optical element corresponding to the vertical field of view angle of -30° to +10° can be regulated to emit light, and the optical element corresponding to the vertical field of view angle of +10° to +30° can be regulated not to emit light. It should be understood that the area of the receiving chip also needs to be increased accordingly to receive the reflected light signal of the entire detection field of view.

[0041] Example 2:

[0042] In order to reduce the chip area, lower the cost, and realize the miniaturized design of the laser radar 1, in other embodiments of the present application, the laser radar 1 can be tilted relative to the installation plane, so that the detection field of the laser radar 1 is offset along a preset direction in the target detection area, and the detection field of view is adapted to the target sub-area in the multiple sub-areas. In a specific embodiment, the detection field of the laser radar 1 is offset along the vertical direction in the target detection area. When the laser radar 1 is set on the car, the laser radar is installed on the car at an angle so that the main optical axis of the laser radar is not parallel to the ground. For example, please refer to Figure 3 , the horizontal direction 31 (0°) is parallel to the ground. After the tilt setting, the field of view angle of the pulse beam emitted by the transmitter 11 and the field of view angle of the reflected beam collected by the collector 12 are offset downward along the vertical direction. The main optical axis of the laser radar 1 has an angle with the horizontal direction 31. In this way, the detection field of the laser radar 1 is offset in the target detection area. For example Figure 3 In the embodiment, the detection field of view is asymmetrically distributed along the horizontal direction 31. If the vertical field of view of the laser radar 1 is -20° to +20°, it becomes -30° to 10°. This part of the area is exactly the area of interest that needs to be detected when the laser radar 1 is installed on the car. That is, the laser radar offset is set to make the detection field of view of the laser radar adapt to the target sub-area. In this way, when designing the area size of the transmitting and receiving chips, the corresponding preset detection field of view is -20° to +20°, so there is no need to design a larger area to meet the detection requirements. Compared with Example 1, the detection field of the laser radar partially covers the target detection field of view. It should be noted that Figure 3 This is a schematic diagram of the main light axis being offset toward the ground (i.e., tilted downward). In actual applications, it can also be offset in the opposite direction to the ground (i.e., upward).

[0043] Since the light intensity of the pulse light beam emitted at the main optical axis of the laser radar 1 is higher than that of the pulse light beams emitted at other angles, and the center area of the target detection area is no longer located on the main optical axis of the laser radar 1 by tilting the laser radar, this tilting setting method will cause a loss of ranging performance in the center area. In order to compensate for the loss of ranging performance, the control and processing circuit is also used to control the transmitter 11 to emit a pulse light beam to the target detection area, and adjust the laser parameters of the pulse light beam emitted to the center area of the target detection area to compensate for the ranging performance. Specifically, the laser power, number of pulses, pulse frequency, and multi-frequency ranging can be increased, that is, the ranging performance is compensated by improving the detection accuracy in the center area.

[0044] Specifically, Figure 3 Continuing with this example, in this embodiment, the primary optical axis of the LiDAR 1 is tilted downward along the vertical direction. The central region requiring compensation is the area near a vertical angle of 0 degrees, for example, the area with a vertical field of view angle of -5° to +5°. This central region can correspond to one or more target subregions. To compensate for the loss in ranging performance, the optical element emitting the pulsed beam toward this subregion can be configured to emit a laser power greater than a power threshold and / or a pulse number greater than a threshold, or to emit pulses at two different frequencies to ensure distance uniqueness. In other words, a higher-precision detection method is employed for detection within this target subregion to ensure the same detection accuracy for the central region as for other subregions within the detection field of view. This also facilitates multi-sensor fusion between the LiDAR 1 and other radars. For example, a driving assistance system needs to fuse ranging information collected by the LiDAR 1 with images captured by a camera. Assuming the camera's primary optical axis is also oriented horizontally 31, the ranging information from the LiDAR 1 corresponding to the center of the image captured by the camera has higher accuracy due to the improved ranging performance in the horizontal direction 31, making it easier to match the information during multi-sensor fusion.

[0045] Example 3:

[0046] Generally, for example, in Example 2, the transmitting optical element and the light source array 110 in the transmitter 11 are coaxially designed, and the optical axis of the transmitting optical element, the center of the light source array 110, and the main optical axis of the entire laser radar 1 are coaxial. In other embodiments of the present application, the center of the light source array 110 of the transmitter 11 and the optical axis of the transmitting optical element can be offset so that the detection field of view is asymmetrically distributed along the optical axis of the transmitting optical element, that is, the detection field of view is asymmetrically distributed relative to the main optical axis of the laser radar 1.

[0047] In order to make the detection field of view cover the area of interest, in some embodiments, the image height of the emitting optical element is designed according to the target detection area so that the theoretical detection area of the laser radar 1 will cover the target detection area, wherein the image height is the height at which the lens can form an image. Then, by configuring the light source array to be offset relative to the optical axis of the emitting optical element, the detection field of the laser radar 1 can also be offset in the target detection field of view, and only projected onto the area of interest in the target detection field of view. At this time, the area of the light source array can be designed according to the size of the area of interest. In actual applications, the image height can also be increased by adjusting the lens design after the offset setting, so as to increase the vertical field angle of the imaging of the emitting optical element. Of course, if the theoretical detection area of the laser radar 1 already covers the target detection area after the offset setting, then the image height does not need to be adjusted.

[0048] However, the area of the light source array 110 has not increased, and the actual vertical field angle range that can be projected has not changed. Figure 4 As the image height increases, the vertical field of view of the emitting optical element increases from -20° to +20° to -30° to +30° (target detection area). Since the region of interest itself is located between -30° and +10°, the area of the light source array 110 can be configured to support a vertical field of view of 40°. Therefore, the center of the light source array 110 is offset from the optical axis of the emitting optical element. At this time, the pulse light beam emitted by the light source array 110 can cover the area between -30° and +10°. The actual detection field of view, that is, the area between -30° and +10°, is asymmetrically distributed along the optical axis of the emitting optical element.

[0049] It should be understood that the center of the light source array 110 can be offset in a direction perpendicular to the optical axis of the emitting optical element and opposite to the relative direction of the target sub-region in the detection field of view and the main optical axis of the lidar 1. In other words, if the region of interest is below the optical axis of the emitting optical element, then the center of the light source array 110 should be moved upward along the direction perpendicular to the optical axis. Because of the pinhole imaging principle, the layout of the emitting chip is opposite to the target field of view.

[0050] It should be understood that the image height of the receiving optical element in the collector 12 needs to be increased accordingly, and the center of the pixel array 120 should also be offset from the optical axis of the receiving optical element to collect the emitted light signal within the detection field of view, and the offset direction of the pixel array 120 is the same as the offset direction of the light source array 110.

[0051] Example 4:

[0052] In the aforementioned embodiment, the target detection area is mainly divided into target sub-areas and non-target sub-areas, and the pulses emitted by the light source array are projected onto the target sub-areas. In other embodiments of the present application, the laser parameters of the pulsed light beam in each sub-area can be adjusted to achieve dynamic regulation of different sub-areas. Specifically, the target detection area is divided into a plurality of non-overlapping sub-areas along a preset direction, and the light source array 110 includes a sub-light source array corresponding to each sub-area in the plurality of sub-areas. For example, Figure 5a As shown, the target detection area can be divided into a plurality of sub-areas along the vertical direction of the target detection area, such as 501. Accordingly, the light source array 110 is also divided into a plurality of sub-light source arrays.

[0053] In this case, the control and processing circuit can be used to control different sub-light source arrays in the transmitter 11 to emit pulsed light beams to corresponding sub-areas, and to adjust the laser parameters of the pulsed light beams emitted by at least some of the sub-light source arrays to be different, thereby achieving different detection accuracy for different sub-areas by the lidar 1. Specifically, the configured laser parameters include one or more of laser power, number of pulses, pulse frequency, and pulses of different frequencies.

[0054] For example, if the vertical field of view corresponding to the detection field of view is an area from -20° to +20°, then every 10° along the vertical direction is divided into a sub-area, resulting in four sub-areas: -20° to -10°, -10° to 0°, 0° to +10°, and +10° to +20°. At this time, considering the waste of the light beam projected to the sky, the number of pulse transmissions and peak power in the +10° to +20° sub-area can be reduced, and only a pulse beam of one frequency can be emitted, and the pulse frequency can be reduced. The number of T pulse transmissions and peak power in the -20° to -10°, -10° to 0°, and 0° to +10° sub-areas can be increased, and pulse beams of two frequencies can be emitted, and the pulse frequency can be increased. Taking into account that the target is concentrated in the central field of view, the number of pulse emissions and peak power in the -20° to -10° and +10° to +20° sub-areas can be reduced, and a single-frequency emission algorithm can be adopted; the number of pulse emissions and peak power in the -10° to 0° and 0° to +10° sub-areas can be increased, and a dual-frequency ranging algorithm can be adopted. In this way, the laser parameters of the pulse light beams emitted into the sub-areas are different, so as to improve the detection accuracy of some sub-areas (areas of interest).

[0055] It is understood that when different modulations are applied to the light source array 110, the corresponding collector 12 will also be configured accordingly. By performing different types of modulation and demodulation on the light emitting elements and pixels corresponding to different sub-areas, adaptive measurement of different sub-areas can be achieved.

[0056] Embodiment 5:

[0057] It can be understood that in the aforementioned embodiments, the target detection area is mainly divided according to one direction, such as the vertical direction. There may also be different detection requirements for multiple sub-areas, such as high ranging requirements in the center area and low ranging requirements in the edge area. Therefore, a solution for dynamic control of partitions that are not along a certain direction is proposed. In other embodiments of the present application, the target detection area may include multiple detection unit areas, and each sub-area includes at least one detection unit area. The light source array 110 includes a sub-light source array corresponding to each detection unit area. The control and processing circuit controls the sub-light source arrays corresponding to all detection unit areas in each sub-area to be turned on at the same time, and the laser parameters of the laser pulses emitted by all sub-light source arrays corresponding to each sub-area are the same, while the pulse parameters of the laser pulses in different sub-areas are different, specifically, determined according to the detection accuracy of each sub-area.

[0058] In other words, the sub-regions are not directly divided along a certain direction as a reference, but the target detection area is directly divided into multiple detection unit areas, and any one or more unit areas are combined into a sub-region. It is understandable that in the embodiments of the present application, the size and position of the sub-regions are not fixed and can be adjusted according to specific measurement requirements. For example, some sub-regions may include only one detection unit area, while some sub-regions may include three detection unit areas; the detection unit areas in the same sub-region may be adjacent or non-adjacent in space. Figure 5b A schematic diagram of sub-area division is shown, wherein each small grid is a detection unit area 502, and the oblique lines, cross lines and blank spaces each represent a sub-area, such as 503. Furthermore, the sub-light source arrays corresponding to these detection unit areas can be turned on simultaneously to detect the corresponding sub-areas.

[0059] Accordingly, the control and processing circuit can also control the emitter 11 to emit pulsed light beams to the corresponding sub-areas through different sub-light source arrays, and adjust the laser parameters of the pulsed light beams emitted to the sub-areas to be different, so as to obtain different detection accuracies for different sub-areas. The configuration of the laser parameters is the same as above.

[0060] It is understood that when different modulations are applied to the light source array 110, the corresponding collector 12 will also be configured accordingly. By performing different types of modulation and demodulation on the light emitting elements and pixels corresponding to different sub-areas, adaptive measurement of different sub-areas can be achieved.

[0061] Through dynamic division of sub-areas, the laser radar can also make dynamic adjustments according to target movement and detection scenes. Specifically, the control and processing circuit is also used to determine the target sub-area where the target will be located at the next detection moment based on the sub-area where the current target is located, and control the transmitter 11 to transmit a pulse light beam to the corresponding target sub-area at the next detection moment. Specifically, the laser radar 1 can determine the moving speed and direction of the target based on the sub-area where the current target is located and the sub-area where the target was located at the previous detection moment, and then estimate the target sub-area at the next detection moment. It can be understood that, under normal circumstances, the target sub-area at the next moment has the same number of detection unit areas as the target sub-area at the previous moment, and only emits an offset along a certain direction.

[0062] Furthermore, the present application also provides a laser radar detection method, comprising:

[0063] emitting a pulse light beam to a target detection area, wherein the target detection area includes a plurality of sub-areas, and the pulse light beam emitted to each of the plurality of sub-areas is at least partially different;

[0064] collecting the pulsed light beam reflected by the target in the target detection area;

[0065] The flight time of the pulse beam from emission to collection is calculated to obtain the distance of the target, so that the lidar has different detection accuracy for different sub-areas.

[0066] It should be noted that, for the sake of simplicity of description, the aforementioned method embodiments are all expressed as a series of action combinations. However, those skilled in the art should be aware that this application is not limited to the described order of actions, because according to this application, certain steps can be performed in other orders.

[0067] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0068] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0069] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A laser radar, characterized in that: The laser radar includes a transmitter, a collector, and a control and processing circuit connected to the transmitter and the collector respectively; The transmitter is used to emit a pulse light beam to a target detection area, wherein the target detection area includes a plurality of sub-areas; the sub-area corresponding to the area of interest is defined as a target sub-area, and the sub-area corresponding to the area of non-interest is defined as a non-target sub-area; the main optical axis of the laser radar is configured to be tilted relative to the mounting plane so that the detection field of view of the laser radar is offset along a preset direction in the target detection area, and the detection field of view is adapted to the target sub-areas in the plurality of sub-areas; and the center area of the target detection area is no longer located on the main optical axis of the laser radar by tilting the laser radar; The collector is used to collect the pulse light beam reflected by the target in the target detection area; The control and processing circuit is used to synchronously control the emitter and the collector, and calculate the flight time of the pulse light beam from emission to collection by the collector to obtain the distance of the target; The transmitter is configured to transmit a pulsed light beam that is at least partially different to each of the multiple sub-areas, so that the laser radar has different ranging capabilities and detection accuracy for different sub-areas; The control and processing circuit is also used to control the emitter to emit a pulse light beam to the target detection area, and adjust the laser parameters of the pulse light beam emitted to the central area of the target detection area to compensate for the ranging performance, wherein the central area corresponds to one or more sub-areas.

2. The laser radar according to claim 1, wherein The transmitter includes a light source array, and the pulse light beams emitted by the light source array are symmetrically distributed along the main optical axis of the laser radar. The area of the light source array is configured so that the emission field of view corresponding to the pulse light beams emitted by the light source array covers the target detection area.

3. The laser radar according to claim 2, wherein: The control and processing circuit is used to control the emitter to emit a pulsed light beam toward a target sub-area among the multiple sub-areas; Alternatively, the control and processing circuit is used to control the emitter to emit a pulsed light beam to each of the sub-areas, and configure the laser parameters of the pulsed light beam emitted to the target sub-area to be different from the laser parameters of the pulsed light beam emitted to non-target sub-areas among the multiple sub-areas.

4. The laser radar according to claim 1, wherein The transmitter includes a transmitting optical element and a light source array; Configuring the image height of the transmitting optical element so that the theoretical detection area of the laser radar covers the target detection area; The center of the light source array is configured to be offset from the optical axis of the emitting optical element so that the pulse light beam emitted by the light source array is projected onto a portion of the sub-area in the target detection area.

5. The laser radar according to claim 1, wherein The multiple sub-regions are distributed non-overlappingly along a preset direction, the emitter includes a light source array, and the light source array includes a sub-light source array corresponding to each of the multiple sub-regions one by one; The control and processing circuit is used to control each of the sub-light source arrays to emit a pulsed light beam to a corresponding sub-region, wherein the laser parameters of the pulsed light beams emitted by at least some of the sub-light source arrays are different.

6. The laser radar according to any one of claims 1 to 5, characterized in that The target detection area includes a plurality of detection unit areas, and each of the sub-areas includes at least one detection unit area; The emitter includes a light source array, and the light source array includes a sub-light source array corresponding to each of the detection unit areas; The control and processing circuit controls the sub-light source arrays corresponding to all detection unit areas contained in the sub-area to be turned on simultaneously, and configures the laser parameters of the laser pulses emitted by all the sub-light source arrays corresponding to each sub-area to be the same.

7. The laser radar according to claim 6, wherein: The control and processing circuit is also used to determine the target sub-area where the target is located at the next detection moment based on the sub-area where the target is currently located, and control the transmitter to emit a pulse light beam to the target sub-area where the target is located at the next detection moment.

8. A laser radar detection method, characterized in that: The detection method is applied to the laser radar according to any one of claims 1 to 7, and the detection method includes: emitting a pulse light beam to a target detection area, wherein the target detection area includes a plurality of sub-areas, and the pulse light beam emitted to each sub-area of the plurality of sub-areas is at least partially different; collecting the pulse light beam reflected by the target in the target detection area; The flight time of the pulse light beam from emission to collection is calculated to obtain the distance of the target, so that the laser radar has different detection accuracy for different sub-areas.

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