Laser radar and detection method

Abstract

The present invention relates to a laser radar and detection method. The laser radar comprises a main control unit and at least one set of detection pathways. Each detection pathway comprises a first light-emitting device, a transmitting lens group, a first photoelectric receiving device, a receiving lens group, and at least one optical path amplification device. The optical path amplification device is used to amplify the detection optical path so that the intersection of the detection light spot and the detection field of view in the standard detection pathway is located behind the intersection of the detection light spot and the detection field of view in the auxiliary detection pathway. The technical solution of an embodiment of the present invention achieves detection of objects at different distances by providing a fixed optical path amplification device, eliminating the need for a mechanical adjustment device. Therefore, it can accommodate detection requirements at different distances while meeting both stability and reliability requirements.

Description

Technical Field

[0001] The present invention generally relates to the field of laser radar technology. More specifically, the present invention relates to a laser radar and a detection method. Background Art

[0002] With the development of lidar technology, its applications are becoming increasingly widespread, with the largest application area being autonomous vehicles. As the "eyes" of autonomous vehicles, lidar boasts superior detection accuracy to other sensors, capable of sensing the distance information of objects around the vehicle, making it an indispensable sensor for autonomous vehicles. For autonomous vehicles, both long-range and short-range vehicle information are crucial for autonomous driving control strategies. However, because the long-range detection lidar's light detection area and the lidar's echo signal receiving field of view do not intersect at close range, creating a ranging "blind spot," long-range detection lidar cannot accurately provide close-range vehicle information.

[0003] LiDAR (LiDAR) detection works by using an optical lens to image the LiDAR's detection spot onto a photoelectric receiver, enabling energy detection and, consequently, distance measurement. Due to the optical lens principle, if the image of a close-range object is optimally captured by the photoelectric receiver, the image of a distant object will be poor, affecting long-range detection. Conversely, if the image of a distant object is optimally captured by the photoelectric receiver, the image of a close-range object will be poor, affecting close-range detection. Therefore, LiDAR is typically configured in two ways: long-range detection LiDAR and short-range blind spot compensation LiDAR. Long-range detection LiDAR is suitable for long-range detection but has blind spots at close range. Short-range blind spot compensation LiDAR, on the other hand, has a smaller blind spot but is not suitable for long-range detection. To address both long-range and short-range detection requirements for LiDAR, optical zoom is commonly used in the imaging field. However, mechanical zoom typically requires a mechanical adjustment mechanism, which is not only slow but also struggles to meet stability and reliability requirements under vehicle vibration.

[0004] Therefore, for lidar, how to take into account the detection needs of different distances while meeting the requirements of stability and reliability is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] To solve one or more of the above technical problems, the present invention proposes to amplify the detection optical path by providing an optical path amplification device. To this end, the present invention provides solutions in the following aspects.

[0006] In a first aspect, the present invention discloses a laser radar, comprising: a main control unit and at least one group of detection paths, each group of detection paths comprising: a first light-emitting device, a transmitting lens group, a first photoelectric receiving device, a receiving lens group, and at least one optical path expansion device; wherein the first light-emitting device is located at the focus of the transmitting lens group, the first photoelectric receiving device is located at the focus of the receiving lens group, and the optical path expansion device is used to expand the detection optical path so that the intersection of the detection light spot and the detection field of view in the standard detection path is located after the intersection of the detection light spot and the detection field of view in the auxiliary detection path. The detection optical path formed by the first light-emitting device, the transmitting lens group, the receiving lens group, and the first photoelectric receiving device is referred to as the standard detection path, and the detection optical path formed by the optical path expansion device, the transmitting lens group, and the receiving lens group is referred to as the auxiliary detection path; the standard detection path is used to detect objects to be measured at a distance greater than or equal to a first preset distance, and the auxiliary detection path is used to detect objects to be measured at a distance greater than or equal to a second preset distance and less than the first preset distance, and the auxiliary detection path starts and / or ends at the optical path expansion device.

[0007] In a specific implementation of an embodiment of the present invention, for each group of detection paths: the optical path amplification device includes: a second light-emitting device, the distance between the second light-emitting device and the emitting lens group is less than or equal to the distance between the first light-emitting device and the emitting lens group, and the second light-emitting device is not located on the main optical axis of the emitting lens group.

[0008] In a specific implementation of the embodiment of the present invention, the second light emitting device is not located on the light path of the standard detection channel.

[0009] In a specific implementation of an embodiment of the present invention, for each group of detection paths: the optical path amplification device includes: a second photoelectric receiving device, the distance between the second photoelectric receiving device and the receiving lens group is less than or equal to the distance between the first photoelectric receiving device and the receiving lens group, and the second photoelectric receiving device is not located on the main optical axis of the receiving lens group.

[0010] In a specific implementation of the embodiment of the present invention, the second photoelectric receiving device is not located on the optical path of the standard detection path.

[0011] In a specific implementation of an embodiment of the present invention, for each group of detection paths: the optical path amplification device includes: a third light-emitting device and a third photoelectric receiving device, the distance between the third light-emitting device and the emitting lens group is less than or equal to the distance between the first light-emitting device and the emitting lens group, and the third light-emitting device is not located on the main optical axis of the emitting lens group, the distance between the third photoelectric receiving device and the receiving lens group is less than or equal to the distance between the first photoelectric receiving device and the receiving lens group, and the third photoelectric receiving device is not located on the main optical axis of the receiving lens group.

[0012] In a specific implementation of the embodiment of the present invention, the third light emitting device is not located on the optical path of the standard detection path, and / or the third photoelectric receiving device is not located on the optical path of the standard detection path.

[0013] In a specific implementation of an embodiment of the present invention, for each group of detection paths: a light-emitting control circuit and a receiving circuit are provided; wherein, the light-emitting control circuit is used to generate a driving electrical signal to drive the light-emitting device in the detection path to emit light, and the receiving circuit is used to receive the electrical signal converted by the photoelectric receiving device in the detection path and convert it into an electrical signal that can be detected by the main control unit.

[0014] In a second aspect, a detection method is applied to the laser radar described in any one of the first aspects, comprising: the main control unit obtains the light-emitting time of the light-emitting device in each group of detection paths and the reception time of the laser echo signal returned by each group of detection paths; the main control unit calculates the obstacle distance based on the light-emitting time and the reception time.

[0015] In a specific implementation of the embodiment of the present invention, the main control unit obtains the light-emitting moment of the light-emitting device in each group of detection paths and the reception moment of the laser echo signal returned by each group of detection paths, including: for each group of detection paths: the main control unit controls the light-emitting device in the standard detection path to emit light and records a first light-emitting moment, and regards the first light-emitting moment as the light-emitting moment; the main control unit starts timing at the first light-emitting moment, and when the laser echo signal in the standard detection path is received before the timing time reaches a first timing threshold, the main control unit ends timing and records a first reception moment, and regards the first reception moment as the reception moment; when the laser echo signal in the standard detection path is not received when the timing time reaches the first timing threshold, the main control unit controls the light-emitting device in the auxiliary detection path to emit light and records a second light-emitting moment, and regards the second light-emitting moment as the light-emitting moment; the main control unit starts timing at the second light-emitting moment, and when the laser echo signal in the auxiliary detection path is received before the timing time reaches the second timing threshold, the main control unit ends timing and records a second reception moment, and regards the second reception moment as the reception moment.

[0016] Embodiments of the present invention provide a laser radar and detection method. By incorporating an optical path amplification device into the laser radar, the method creates at least two intersection points at different distances between the laser radar's detection spot and its field of view, each capable of detecting objects at different distances. This technical solution, achieved by installing a fixed optical path amplification device, eliminates the need for mechanical adjustment devices, thus accommodating detection requirements at varying distances while meeting both stability and reliability requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an illustrative and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0018] Figure 1 1 is a schematic structural diagram of a laser radar provided by an embodiment of the present invention;

[0019] Figure 2 1 is a schematic structural diagram of another laser radar provided by an embodiment of the present invention;

[0020] Figure 3 is a schematic structural diagram of another laser radar provided by an embodiment of the present invention;

[0021] Figure 4 1 is a schematic structural diagram of another laser radar provided by an embodiment of the present invention;

[0022] Figure 5 It is a flowchart of a detection method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0024] As mentioned above, due to its advantages such as high distance detection accuracy, lidar has been widely used in fields such as autonomous vehicles. However, due to the limitations of optical lens principles, the lidar transceiver system, which includes the light-emitting device, transmitting lens assembly, photoelectric receiving device, and receiving lens assembly, can generally only achieve optimal detection of objects within a certain distance range. For objects within other distance ranges, detection results may be inaccurate or even result in blind spots.

[0025] For example, in the autonomous vehicle sector, on a specific vehicle model, long-range detection lidar can accurately detect objects at distances greater than 150m, but its resolution reliability is reduced for objects less than 10m, and it may even be completely undetectable for objects less than 6m. In contrast, short-range blind spot detection lidar is typically used for objects less than 50m and can generally accurately detect objects between 0m and 50m. To detect objects at different distances and reduce blind spots in autonomous vehicles, one solution is to deploy long-range detection lidar and short-range blind spot detection lidar separately. However, due to the high cost of lidar, this would undoubtedly significantly increase the manufacturing cost of the autonomous vehicle, and the addition of more lidars would complicate the vehicle's spatial layout and wiring. Another solution is to integrate long-range and short-range detection functions into a single lidar, typically using optical zoom. However, mechanical zoom typically requires a mechanical adjustment mechanism, which is not only slow but also difficult to meet stability and reliability requirements under vehicle vibration conditions.

[0026] It's important to note that in different application areas or scenarios, the detection ranges of long-range detection lidar and short-range blind spot compensation lidar are different. Even within the same application area, the detection ranges of long-range detection lidar and short-range blind spot compensation lidar are different. For example, in the field of autonomous vehicles, the distance range of the lidar used for side detection is obviously smaller than the distance range of the lidar used for forward detection. Therefore, the two have different definitions of "far and near". However, regardless of the application area or scenario, the essence is the need for a lidar that can meet the different distance detection requirements while also meeting the requirements for stability and reliability.

[0027] Based on this, an embodiment of the present invention sets an optical path amplification device in the laser radar so that there are at least two intersection points of different distances between the detection spot and the detection field of view of the laser radar, which can be used to detect objects at different distances.

[0028] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] See also Figure 1 FIG. 1 is a schematic diagram of the structure of a laser radar provided by an embodiment of the present invention. The laser radar comprises: a main control unit 10 and at least one set of detection channels 20 .

[0030] Each detection path 20 includes a first light emitting device 21 , a transmitting lens group 22 , a first photoelectric receiving device 23 , a receiving lens group 24 and at least one optical path amplification device 25 .

[0031] In actual use, the main control unit 10 is used for signal processing and control. Specifically, the main control unit 10 controls the light emission of the light-emitting device (such as the first light-emitting device 21), and is used to receive the laser echo signal through the photoelectric receiving device (such as the first photoelectric receiving device 23), and records the light emission time of the light-emitting device and the reception time of the laser echo signal, and calculates the distance of the object being measured based on the light emission time of the light-emitting device, the reception time of the laser echo signal and the speed of light. The main control unit 10 can be a board capable of signal processing and control, such as a DSP (Digital Signal Processing) or an FPGA (Field-Programmable Gate Array). The light-emitting device (such as the first light-emitting device 21) is used to generate a ranging laser, and can be a commonly used laser generating device such as an EEL (Edge Emitting Laser), a VCSEL (Vertical-Cavity Surface-Emitting Laser), or a fiber laser. The transmitting lens assembly 22 collimates and compresses the ranging laser light generated by the light-emitting device. The receiving lens assembly 24 receives the laser echo signal diffusely reflected by the measured object and focuses it on the photoelectric receiving device. The photoelectric receiving device (such as the first photoelectric receiving device 23) converts the received laser echo signal into an electrical signal. The photoelectric receiving device can be a photodiode, avalanche diode, silicon photomultiplier tube, etc.

[0032] It should be noted that Figure 1 Only one set of detection channels 20 is shown in the figure. However, in actual applications, the laser radar may include two or more sets of detection channels 20. For example, in a multi-line laser radar, each line corresponds to a set of detection channels 20. In addition, each set of detection channels 20 may also include two or more optical path amplification devices.

[0033] Below Figure 1To further illustrate the laser radar shown, the first light-emitting device 21 is located at the focal point of the transmitting lens group 22, and the first photoelectric receiving device 23 is located at the focal point of the receiving lens group 24. The optical path expansion device 25 is used to expand the detection optical path so that the intersection of the detection light spot and the detection field of view in the standard detection path is located behind the intersection of the detection light spot and the detection field of view in the auxiliary detection path. Specifically, the detection optical path formed by the first light-emitting device 21, the transmitting lens group 22, the receiving lens group 24, and the first photoelectric receiving device 23 is the standard detection path; the detection optical path formed by the optical path expansion device 25, the transmitting lens group 22, and the receiving lens group 24 is the auxiliary detection path, which begins and / or ends at the optical path expansion device 25. The standard detection path is used to detect objects at a distance greater than or equal to a first preset distance, while the auxiliary detection path is used to detect objects at a distance greater than or equal to a second preset distance and less than the first preset distance. The first preset distance is greater than the second preset distance.

[0034] It should be noted that the detection spot refers to the luminous detection area formed behind the transmitting lens group by the light-emitting device in a detection path. The detection field of view refers to the range of echo signals received by the photoelectric receiving device behind the receiving lens group 24 in a detection path, which is also the echo signal receiving field of view of the lidar. Taking the standard detection path as an example, the luminous detection area formed by the first light-emitting device 21 behind the transmitting lens group 22 is the detection spot of the standard detection path, and the range of echo signals received by the first photoelectric receiving device 23 behind the receiving lens group 24 is the detection field of view of the standard detection path.

[0035] In addition, the intersection of the detection light spot and the detection field of view in the standard detection path is located after the intersection of the detection light spot and the detection field of view in the auxiliary detection path, which means that the intersection of the detection light spot and the detection field of view in the standard detection path is farther away from the laser radar itself than the intersection of the detection light spot and the detection field of view in the auxiliary detection path. In this way, the standard detection path can detect objects located after the intersection of the detection light spot and the detection field of view in the standard detection path, and the auxiliary detection path can detect objects located after the intersection of the detection light spot and the detection field of view in the auxiliary detection path, thereby taking into account the detection needs of different distances. Among them, the position of the intersection of the detection light spot and the detection field of view in the standard detection path corresponds to the first preset distance, and the position of the intersection of the detection light spot and the detection field of view in the auxiliary detection path corresponds to the second preset distance. In actual applications, the size of the first preset distance and the size of the second preset distance are determined according to actual detection requirements, and the position and distance relationship of the first light-emitting device, the transmitting lens group, the first photoelectric receiving device, the receiving lens group and the optical path amplification device in the laser radar are adjusted accordingly. The specific adjustment can be determined according to the principle of optical propagation and will not be repeated here.

[0036] The auxiliary detection path begins at optical path amplifier device 25, meaning that optical path amplifier device 25 is a light-emitting device in the auxiliary detection path. The auxiliary detection path ends at optical path amplifier device 25, meaning that optical path amplifier device 25 is a photoelectric receiving device in the auxiliary detection path. In other words, optical path amplifier device 25 is a light-emitting device and / or a photoelectric receiving device.

[0037] It should be noted that due to the limitations of optical principles, the intersection of the detection spot and the detection field of view in the standard detection path is located after the intersection of the detection spot and the detection field of view in the auxiliary detection path. This means that the distance between the optical path expansion device 25 and the corresponding lens group should be less than or equal to the distance between the device corresponding to the optical path expansion device 25 and the corresponding lens group in the standard detection path. For example, when the optical path expansion device 25 is a light-emitting device, the distance between the optical path expansion device 25 and the emission lens group 22 is less than or equal to the distance between the first light-emitting device 21 and the emission lens group 22. The distance between the optical path expansion device 25 and the corresponding lens group, as well as the distance between the device corresponding to the optical path expansion device 25 and the corresponding lens group in the standard detection path, should be understood as the projection distance of the line connecting the device center and the lens group center onto the principal optical axis of the lens group. In other words, the distance between the optical path expansion device 25 and the corresponding lens group, as well as the distance between the device corresponding to the optical path expansion device 25 and the corresponding lens group in the standard detection path, should be understood as the distance from the device to a plane passing through the optical center and perpendicular to the principal optical axis of the corresponding lens group. The optical center here is also the lens center.

[0038] For ease of understanding, the operating process of the laser radar in an embodiment of the present invention is described herein. Taking the optical path expansion device 25 as a light-emitting device as an example, for each detection path 20, the main control unit 20 controls the first light-emitting device 21 to emit light and records the first light-emitting moment. The light emitted by the first light-emitting device 21 passes through the transmitting lens group 22 to form a detection spot for the standard detection path. The echo signal formed by this detection spot after reflection from the detected object, the range of the echo signal that may be received by the first photoelectric receiving device 23, constitutes the detection field of view of the standard detection path. The intersection of the detection field of view of the standard detection path and the detection spot is denoted as point P. The main control circuit 20 receives the echo signal received by the first photoelectric receiving device 23 and records the first reception moment. The main control unit calculates the detection of the detected object located after point P based on the first light-emitting moment and the first reception moment in combination with the speed of light. Similarly, the main control unit 20 controls the optical path expansion device 25 to emit light and records the second light-emitting moment. The light emitted by the optical path expansion device 25 passes through the emitting lens group 22 to form a detection light spot of the auxiliary detection path. The echo signal formed after the detection light spot is reflected by the object to be measured, and the range of echo signals that may be received by the first photoelectric receiving device 23 constitutes the detection field of view of the auxiliary detection path. The intersection between the detection field of view of the auxiliary detection path and the detection light spot is recorded as point O. The main control circuit 20 receives the echo signal received by the first photoelectric receiving device 23 and records the second receiving moment. The main control unit calculates the detection of the object to be measured located after point O based on the second light-emitting moment and the second receiving moment combined with the speed of light.

[0039] It should be further explained that, since the first light-emitting device 21 is located at the focal point of the transmitting lens group 22, the first photoelectric receiving device 23 is located at the focal point of the receiving lens group 24, and the intersection of the detection field of view of the standard detection path and the detection light spot is denoted as point P, the standard detection path can be used to image the object under test located after point P at the focal point of the receiving lens group 24, thereby enabling detection of relatively distant objects under test. Theoretically, the auxiliary detection path can be used to detect objects under test located after point O, and objects under test located after point P can also be detected. However, due to optical principles, the auxiliary detection path has a poor imaging effect on objects under test located after point P. Therefore, the auxiliary detection path is used here to detect objects under test located between points O and P.

[0040] In specific implementations, the auxiliary detection path can be used to detect objects located between point O and point P by setting a time threshold. For example, assuming the duration between the light emission and reception of the object at point P is T, the auxiliary detection path only calculates the distance corresponding to the echo signal whose duration between the light emission and reception is within T. If the duration between the light emission and reception is greater than T, the distance is directly ignored. It is understood that the present invention is not limited to this. In other implementations, if the distance of the object detected by the auxiliary detection path is beyond point P, the result can be directly set as unreliable.

[0041] In addition, it is obvious that the requirements for ranging in different scenarios are different, and the first preset distance and the second preset distance are also different. Therefore, the distance and position relationship between each device in the standard detection path and the auxiliary detection path should be determined according to the detection effect in the corresponding scenario.

[0042] The lidar provided by the present invention employs an optical path amplification device within each detection path, creating different detection paths within the same lidar. These paths have different intersection distances between the detection spot and the detection field of view, allowing detection of objects at different distances. This technical solution, achieved by installing a fixed optical path amplification device, eliminates the need for mechanical adjustment devices, thus accommodating detection requirements at varying distances while meeting both stability and reliability requirements.

[0043] As mentioned above, the optical path expansion device 25 is in the form of a light emitting device and / or a photoelectric receiving device, which will be described separately later.

[0044] See also Figure 2 , which is a schematic structural diagram of another laser radar provided by an embodiment of the present invention. Specifically, for each set of detection paths, the optical path expansion device 25 includes: a second light emitting device 251.

[0045] It should be noted that Figure 2 In the embodiment, the second light emitting device 251 is located between the first light emitting device 21 and the emission lens group 22 and is not located on the main optical axis of the emission lens group 22. However, in actual applications, the second light emitting device 251 can also be located between the first light emitting device 21 and the emission lens group 22. Figure 2The first light-emitting device 21 is in the same vertical plane, that is, the line connecting the second light-emitting device 251 and the first light-emitting device 21 is perpendicular to the main optical axis of the emitting lens group 22. In other words, the setting position of the second light-emitting device 251 satisfies: the distance between the second light-emitting device 251 and the emitting lens group 22 is less than or equal to the distance between the first light-emitting device 21 and the emitting lens group 22, and the second light-emitting device 251 is not located on the main optical axis of the emitting lens group 22. In addition, the angle of the second light-emitting device 251 relative to the emitting lens group 22 can be the same as or different from the angle of the first light-emitting device 21 relative to the emitting lens group 22, and there can be one or more second light-emitting devices 251, and the second light-emitting device 251 can be located circumferentially of the main optical axis of the emitting lens group 22.

[0046] The following combination Figure 2 The standard detection path and the auxiliary detection path are described in detail.

[0047] Standard detection path: The first light-emitting device 21 is located at the focus of the emitting lens group 22, and emits light under the control of the main control unit 10 to form a detection spot within the angle of the edge light A and the edge light B. The laser echo signal diffusely reflected by the object to be measured converges on the first photoelectric receiving device 23 through the receiving lens group 24, forming a detection field of view within the angle of the edge light E and the edge light F. The detection spot and the detection field of view intersect at point P. When the distance to the object to be measured is less than the distance corresponding to point P (that is, the first preset distance), the detection field of view and the detection spot have no intersection, and the laser radar cannot detect. When the distance to the object to be measured is greater than or equal to the distance corresponding to point P, the detection field of view and the detection spot begin to intersect, and the laser radar begins to obtain the best ranging performance and can be used to detect objects to be measured that are farther away than point P.

[0048] Auxiliary detection path: The second light-emitting device 251 is located between the first light-emitting device 21 and the emitting lens group 22, and at the non-focus of the emitting lens group 22, forming a detection spot within the angle of edge light C and edge light D. The laser echo signal diffusely reflected by the object to be measured converges on the first photoelectric receiving device 23 through the receiving lens group 24. The first photoelectric receiving device 23 is located at the focus of the receiving lens group 24, forming a detection field of view within the angle of edge light E and edge light F. The detection spot and the detection field of view intersect at point O. When the distance to the object to be measured is less than the distance corresponding to point O (that is, the second preset distance), the detection field of view and the detection spot have no intersection, and the laser radar cannot perform detection. When the distance to the object to be measured is greater than or equal to the distance corresponding to point O, the detection field of view and the detection spot begin to intersect, and the laser radar begins to obtain the best ranging performance.

[0049] It is obvious that Figure 2In the illustrated embodiment, the auxiliary detection path and the standard detection path have the same detection field of view, and the amplification of the detection light path is achieved by changing the angle of the detection spot size.

[0050] In this specific embodiment, because the distance corresponding to point O is smaller than the distance corresponding to point P, the auxiliary detection path is more suitable for measuring short distances. Since both the first light-emitting device 21 and the first photoelectric receiving device 23 are at the focal point of their respective lens groups, the standard detection path is more suitable for measuring long distances. Using the standard detection path for long-range detection maintains the long-range measurement capabilities of the LiDAR, while using the auxiliary detection path for short-range detection compensates for the LiDAR's shortcomings in short-range measurement.

[0051] In addition, if the second light-emitting device 251 is located on the standard detection path, it will block the ranging laser emitted by the first light-emitting device 21, thereby affecting the range of the detection light spot and reducing the object detection and ranging capabilities of the standard detection path. To this end, in a specific embodiment of the present invention, the second light-emitting device 251 is not located on the optical path of the standard detection path. The second light-emitting device 251 is not located on the optical path of the standard detection path. Therefore, the formation of the auxiliary detection path does not affect the original standard detection path. On the basis of ensuring the object detection and ranging capabilities of the standard detection path, it can achieve detection of relatively close objects to be measured, reducing detection blind spots.

[0052] See also Figure 3 , which is a schematic structural diagram of another laser radar provided by an embodiment of the present invention. Specifically, for each group of detection paths, the optical path expansion device 25 includes a second photoelectric receiving device 252 .

[0053] It should be noted that Figure 3 The second photoelectric receiving device 252 is located between the first photoelectric receiving device 23 and the receiving lens group 24 and is not located on the main optical axis of the receiving lens group 24. However, in actual applications, the second photoelectric receiving device 252 can also be located between the first photoelectric receiving device 23 and the receiving lens group 24. Figure 3The first photoelectric receiving device 23 is in the same vertical plane, that is, the line connecting the second photoelectric receiving device 252 and the first photoelectric receiving device 23 is perpendicular to the principal optical axis of the receiving lens group 24. In other words, the second photoelectric receiving device 252 is positioned such that the distance between the second photoelectric receiving device 252 and the receiving lens group 24 is less than or equal to the distance between the first photoelectric receiving device 23 and the receiving lens group 24, and the second photoelectric receiving device 252 is not located on the principal optical axis of the receiving lens group 24. In addition, the angle of the second photoelectric receiving device 252 relative to the receiving lens group 24 can be the same as or different from the angle of the first photoelectric receiving device 23 relative to the receiving lens group 24, and there can be one or more second photoelectric receiving devices 252, and the second photoelectric receiving device 252 can be located circumferentially with respect to the principal optical axis of the receiving lens group 24.

[0054] The following combination Figure 3 The standard detection path and the auxiliary detection path are described in detail.

[0055] Standard detection path: The first light-emitting device 21 is located at the focus of the emitting lens group 22. Under the control of the main control unit 10, it emits light to form a detection spot within the angle of the edge light A and the edge light B. The laser echo signal diffusely reflected by the object to be measured converges on the first photoelectric receiving device 23 through the receiving lens group 24, forming a detection field of view within the angle of the edge light E and the edge light F. The detection spot and the detection field of view intersect at point P. When the distance to the object to be measured is less than the distance corresponding to point P (that is, the first preset distance), the detection field of view and the detection spot have no intersection, and the laser radar cannot detect. When the distance to the object to be measured is greater than or equal to the distance corresponding to point P, the detection field of view and the detection spot begin to intersect, and the laser radar begins to obtain the best ranging performance and can be used to detect objects to be measured that are farther away than point P.

[0056] Auxiliary detection path: The ranging laser emitted by the first light-emitting device 21 is diffusely reflected by the object to be measured and then converged on the second photoelectric receiving device 252. The second photoelectric receiving device 252 is located between the first photoelectric receiving device 23 and the receiving lens group 24, and at the non-focus of the receiving lens group 24, forming a detection field of view within the angles of the edge light G and the edge light H. The detection spot and the detection field of view intersect at point O. When the distance to the object to be measured is less than the distance corresponding to point O (that is, the second preset distance), the detection field of view and the detection spot have no intersection, and the laser radar cannot detect. When the distance to the object to be measured is greater than or equal to the distance corresponding to point O, the detection field of view and the detection spot begin to intersect, and the laser radar begins to obtain the best ranging performance.

[0057] It is obvious that Figure 3 In the embodiment shown, the detection light spots of the auxiliary detection path and the standard detection path are the same, and the amplification of the detection light path is achieved by changing the angle of the detection field size.

[0058] In this specific embodiment, because the distance corresponding to point O is smaller than the distance corresponding to point P, the auxiliary detection path is more suitable for measuring short distances. Since both the first light-emitting device 21 and the first photoelectric receiving device 23 are at the focal point of their respective lens groups, the standard detection path is more suitable for measuring long distances. Using the standard detection path for long-range detection maintains the long-range measurement capabilities of the LiDAR, while using the auxiliary detection path for short-range detection compensates for the LiDAR's shortcomings in short-range measurement.

[0059] Furthermore, if the second photoelectric receiver 252 is located in the standard detection path, it will block the detection field of view of the first photoelectric receiver 21, thereby affecting the range of the detection field of view and reducing the object detection and ranging capabilities of the standard detection path. Therefore, in one embodiment of the present invention, the second photoelectric receiver 252 is not located in the optical path of the standard detection path. Therefore, the formation of the auxiliary detection path does not affect the original standard detection path. While maintaining the object detection and ranging capabilities of the standard detection path, it enables detection of relatively close objects and reduces detection blind spots.

[0060] See also Figure 4 , which is a schematic structural diagram of another laser radar provided by an embodiment of the present invention. Specifically, for each set of detection paths, the optical path expansion device 25 includes a third light emitting device 253 and a third photoelectric receiving device 254 .

[0061] It should be noted that Figure 4 The third light emitting device 253 is located between the first light emitting device 21 and the emitting lens group 22 and is not located on the main optical axis of the emitting lens group 22. However, in actual applications, the third light emitting device 253 can also be located between the first light emitting device 21 and the emitting lens group 22. Figure 4 The first light-emitting device 21 is in the same vertical plane, that is, the line connecting the third light-emitting device 253 and the first light-emitting device 21 is perpendicular to the main optical axis of the emitting lens group 22. In other words, the setting position of the third light-emitting device 253 satisfies: the distance between the third light-emitting device 253 and the emitting lens group 22 is less than or equal to the distance between the first light-emitting device 21 and the emitting lens group 22, and the third light-emitting device 253 is not located on the main optical axis of the emitting lens group 22. In addition, the angle of the third light-emitting device 253 relative to the emitting lens group 22 can be the same as or different from the angle of the first light-emitting device 21 relative to the emitting lens group 22, and there can be one or more third light-emitting devices 253, and the third light-emitting device 253 can be located circumferentially of the main optical axis of the emitting lens group 22.

[0062] Correspondingly, Figure 4The third photoelectric receiving device 254 is located between the first photoelectric receiving device 23 and the receiving lens group 24 and is not located on the main optical axis of the receiving lens group 24. However, in actual applications, the third photoelectric receiving device 254 can also be located between the first photoelectric receiving device 23 and the receiving lens group 24. Figure 4 The first photoelectric receiving device 23 is in the same vertical plane, that is, the line connecting the third photoelectric receiving device 254 and the first photoelectric receiving device 23 is perpendicular to the main optical axis of the receiving lens group 24. In other words, the location of the third photoelectric receiving device 254 satisfies the following conditions: the distance between the third photoelectric receiving device 254 and the receiving lens group 24 is less than or equal to the distance between the first photoelectric receiving device 23 and the receiving lens group 24, and the third photoelectric receiving device 254 is not located on the main optical axis of the receiving lens group 24. In addition, the angle of the third photoelectric receiving device 254 relative to the receiving lens group 24 can be the same as or different from the angle of the first photoelectric receiving device 23 relative to the receiving lens group 24, and there can be one or more third photoelectric receiving devices 254, and the third photoelectric receiving device 254 can be located circumferentially of the main optical axis of the receiving lens group 24.

[0063] The following combination Figure 4 The standard detection path and the auxiliary detection path are described in detail.

[0064] Standard detection path: The first light-emitting device 21 is located at the focus of the emitting lens group 22, and emits light under the control of the main control unit 10 to form a detection spot within the angle of the edge light A and the edge light B. The laser echo signal diffusely reflected by the object to be measured converges on the first photoelectric receiving device 23 through the receiving lens group 24, forming a detection field of view within the angle of the edge light E and the edge light F. The detection spot and the detection field of view intersect at point P. When the distance to the object to be measured is less than the distance corresponding to point P (that is, the first preset distance), the detection field of view and the detection spot have no intersection, and the laser radar cannot detect. When the distance to the object to be measured is greater than or equal to the distance corresponding to point P, the detection field of view and the detection spot begin to intersect, and the laser radar begins to obtain the best ranging performance and can be used to detect objects to be measured that are farther away than point P.

[0065] Auxiliary detection path: The third light-emitting device 253 is located between the first light-emitting device 21 and the emitting lens group 22, and at the non-focus of the emitting lens group 14, forming a detection spot within the angle of edge light C and edge light D. The laser echo signal diffusely reflected by the object to be measured converges on the third photoelectric receiving device 254 through the receiving lens group 24. The third photoelectric receiving device 254 is located between the first photoelectric receiving device 23 and the receiving lens group 24, and at the non-focus of the receiving lens group 24, forming a detection field of view within the angle of edge light G and edge light H. The detection spot and the detection field of view intersect at point O. When the distance to the object to be measured is less than the distance corresponding to point O (that is, the second preset distance), the detection field of view and the detection spot have no intersection, and the laser radar cannot detect. When the distance to the object to be measured is greater than or equal to the distance corresponding to point O, the detection field of view and the detection spot begin to intersect, and the laser radar begins to obtain the best ranging performance.

[0066] It is obvious that Figure 4 In the illustrated embodiment, the detection spots and detection fields of the auxiliary detection path and the standard detection path are different, and the amplification of the detection light path is achieved by simultaneously changing the angles of the detection spot size and the detection field size.

[0067] In this specific embodiment, because the distance corresponding to point O is smaller than the distance corresponding to point P, the auxiliary detection path is more suitable for measuring short distances. Since both the first light-emitting device 21 and the first photoelectric receiving device 23 are at the focal point of their respective lens groups, the standard detection path is more suitable for measuring long distances. Using the standard detection path for long-range detection maintains the long-range measurement capabilities of the LiDAR, while using the auxiliary detection path for short-range detection compensates for the LiDAR's shortcomings in short-range measurement.

[0068] In addition, if the third light-emitting device 253 is located on the standard detection path, it will block the ranging laser emitted by the first light-emitting device 21, thereby affecting the range of the detection light spot corresponding to the first light-emitting device 21 and reducing the object detection and ranging capabilities of the standard detection path. If the third photoelectric receiving device 254 is located on the standard detection path, it will block the detection field of view of the first photoelectric receiving device 21, thereby affecting the range of the detection field of view and reducing the object detection and ranging capabilities of the standard detection path. To this end, in a specific embodiment of the present invention, the third light-emitting device 253 is not located on the optical path of the standard detection path, and / or the third photoelectric receiving device 254 is not located on the optical path of the standard detection path.

[0069] In actual applications, the light-emitting devices of the laser radar need to be driven by corresponding control circuits to emit light. At the same time, the amplitude of the laser echo signal directly obtained by the photoelectric receiving device is relatively low. Usually, the electrical signal converted by the photoelectric receiving device needs to be amplified to an amplitude that can be detected by the control unit / board. Therefore, a corresponding receiving circuit needs to be set to amplify the electrical signal converted by the photoelectric receiving device. To this end, in a specific embodiment of the embodiment of the present invention, for each group of detection paths: a light-emitting control circuit and a receiving circuit are provided. The light-emitting control circuit is used to generate a driving electrical signal to drive the light-emitting devices in the detection path to emit light, and the receiving circuit is used to receive the electrical signal converted by the photoelectric receiving device in the detection path and convert it into an electrical signal that can be detected by the main control unit.

[0070] by Figures 2 to 4 Taking the embodiment shown as an example, Figure 2 The photoelectric control circuit 1 261 constitutes the light emitting control circuit of the first light emitting device 21 , the photoelectric control circuit 262 constitutes the light emitting control circuit of the second light emitting device 251 , and the receiving circuit 27 constitutes the receiving circuit of the first photoelectric receiving device 23 . Figure 3 The photoelectric control circuit 26 constitutes the light-emitting control circuit of the first light-emitting device 21 , the receiving circuit 1 271 constitutes the receiving circuit of the first photoelectric receiving device 23 , and the receiving circuit 272 constitutes the receiving circuit of the second photoelectric receiving device 252 . Figure 4 The photoelectric control circuit 1 261 constitutes the light-emitting control circuit of the first light-emitting device 21 , the photoelectric control circuit 262 constitutes the light-emitting control circuit of the third light-emitting device 253 , the receiving circuit 1 271 constitutes the receiving circuit of the first photoelectric receiving device 23 , and the receiving circuit 2 272 constitutes the receiving circuit of the third photoelectric receiving device 254 .

[0071] It should be noted that, in practical applications, the light emitting control circuit and the receiving circuit may also be integrated into the main control unit 10 as part of the main control unit 10 .

[0072] Corresponding to the above-mentioned embodiments of laser radar. Figure 5 As shown, the embodiment of the present application further discloses a detection method applied to the laser radar described in any of the above embodiments, including:

[0073] In step S501 , the main control unit 10 obtains the light-emitting time of the light-emitting devices in each group of detection paths and the receiving time of the laser echo signal returned by each group of detection paths.

[0074] Taking a set of detection paths S as an example, in step S101, the main control unit 10 obtains the lighting time of the first light-emitting device 21 in the standard detection path of detection path S. Simultaneously, the main control unit 10 uses the time of receiving the laser echo signal returned by the first photoelectric receiving device 23 as the reception time. Meanwhile, the main control unit 10 obtains the lighting time of the light-emitting device in the auxiliary detection path of detection path S. Simultaneously, the main control unit 10 uses the time of receiving the laser echo signal returned by the photoelectric receiving device as the reception time. As previously mentioned, the light-emitting devices in the standard detection path and the auxiliary detection path can be the same or different, and the photoelectric receiving devices in the standard detection path and the auxiliary detection path can be the same or different. Specifically, the main control unit 10 is internally provided with a timing circuit or timer. When controlling the lighting of the light-emitting device, the main control unit 10 uses the timing of the timing circuit or timer as the lighting time. When the main control unit 20 obtains the laser echo signal received by the photoelectric receiving device, it uses the timing of the timing circuit or timer as the reception time.

[0075] In step S502 , the main control unit 10 calculates the obstacle distance according to the light emission time and the reception time.

[0076] Specifically, in step S502, the main control unit 10 obtains the time difference between the moment the light-emitting device emits light and the moment the laser echo signal is received, and obtains the obstacle distance according to s=c*t / 2, where s is the obstacle distance, c is the speed of light, and t is the calculated time difference. Obviously, the obstacle is also the object being measured.

[0077] In a specific implementation of an embodiment of the present invention, step S101 includes: for each group of detection paths: the main control unit 10 controls the light-emitting device (i.e., the first light-emitting device 21) in the standard detection path to emit light and records the first light-emitting moment, and the first light-emitting moment is regarded as the light-emitting moment; the main control unit 10 starts timing at the first light-emitting moment, and when the laser echo signal in the standard detection path (i.e., the laser echo signal received by the first photoelectric receiving device 23) is received before the timing time reaches the first timing threshold, the timing is ended and the first receiving moment is recorded, and the first receiving moment is regarded as the receiving moment; when the laser echo signal in the standard detection path is not received when the timing time reaches the first timing threshold, the main control unit 10 controls the light-emitting device in the auxiliary detection path to emit light and records the second light-emitting moment, and the second light-emitting moment is regarded as the light-emitting moment; the main control unit 10 starts timing at the second light-emitting moment, and when the laser echo signal in the auxiliary detection path is received before the timing time reaches the second timing threshold, the timing is ended and the second receiving moment is recorded, and the second receiving moment is regarded as the receiving moment.

[0078] The first timing threshold is determined by the maximum detection distance of the standard detection path, while the second timing threshold is determined by the maximum detection distance of the auxiliary detection path. This determination is based on ensuring that objects at the maximum detection distance can be detected while obtaining the distance to the object as quickly as possible to achieve better real-time performance. For example, on a specific vehicle model, the maximum detection distance of the standard detection path is 250m, while the maximum detection distance of the auxiliary detection path is 50m. During the time period corresponding to the first timing threshold, the laser echo signal reflected by an obstacle at a distance of 250m should be received, while during the time period corresponding to the second timing threshold, the laser echo signal reflected by an obstacle at a distance of 50m should be received.

[0079] In this specific implementation, long-distance detection is performed first, and then close-range detection is performed. This is in line with the working conditions in the field of unmanned vehicles where driving decisions usually need to be made when the distance is greater than a certain distance. At the same time, it can also detect emergencies during the autonomous driving process (close-range objects being measured), reduce visual blind spots, and improve safety.

[0080] It should be noted that in actual applications, step S101 can be implemented in other ways. For example, in another implementation, the objects under test in the standard detection path and the auxiliary detection path can be detected simultaneously. In another implementation, the objects under test in the auxiliary detection path can be detected first, and then the objects under test in the standard detection path can be detected. Step S101 can be implemented in different ways according to the application scenario.

[0081] A detection method provided by an embodiment of the present invention incorporates an optical path amplification device into a laser radar (LIDAR). This method creates at least two intersection points at different distances between the laser radar's detection spot and its field of view, each capable of detecting objects at different distances. This technical solution, achieved by using a fixed optical path amplification device to detect objects at varying distances, eliminates the need for mechanical adjustment devices. Therefore, it can accommodate detection requirements at varying distances while meeting both stability and reliability requirements.

[0082] In the foregoing description of this specification, unless otherwise expressly specified or limited, terms such as "fixed," "mounted," "connected," or "connected" should be understood broadly. For example, the term "connected" can refer to a fixed connection, a removable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediary; or the internal connection between two components or the interaction between two components. Therefore, unless otherwise expressly defined in this specification, those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0083] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", "center", "longitudinal", "lateral", "clockwise" or "counterclockwise", etc., which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operate in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0084] In addition, the terms "first" or "second" used in this specification to refer to numbers or ordinal numbers are used for descriptive purposes only and should not be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this specification, "plurality" means at least two, such as two, three or more, etc., unless otherwise clearly specified.

[0085] Although this specification has shown and described a number of embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will conceive of many modifications, variations, and alternatives without departing from the concept and spirit of the present invention. It should be understood that in practicing the present invention, various alternatives to the embodiments of the present invention described herein may be employed. The appended claims are intended to define the scope of protection of the present invention and therefore cover modular compositions, equivalents, or alternatives within the scope of these claims.

Claims

1. A laser radar, characterized in that: include: A main control unit and at least one set of detection paths, each set of detection paths including: a first light emitting device, a transmitting lens group, a first photoelectric receiving device, a receiving lens group and at least one optical path amplification device; wherein, The first light emitting device is located at the focus of the transmitting lens group, the first photoelectric receiving device is located at the focus of the receiving lens group, and the optical path amplification device is used to amplify the detection optical path so that the intersection of the detection light spot and the detection field of view in the standard detection path is located behind the intersection of the detection light spot and the detection field of view in the auxiliary detection path; The detection optical path formed by the first light-emitting device, the transmitting lens group, the receiving lens group, and the first photoelectric receiving device is referred to as the standard detection path, and the detection optical path formed by the optical path expansion device, the transmitting lens group, and the receiving lens group is referred to as the auxiliary detection path; wherein the optical path expansion device is in the form of a light-emitting device and / or a photoelectric receiving device, and the optical path expansion device is not located on the main optical axis of the transmitting lens group, and the optical path expansion device is not located on the main optical axis of the receiving lens group; The standard detection path is used to detect objects under test at a distance greater than or equal to a first preset distance, and the auxiliary detection path is used to detect objects under test at a distance greater than or equal to a second preset distance and less than the first preset distance. The auxiliary detection path starts and / or ends at the optical path amplification device.

2. The laser radar according to claim 1, characterized in that For each group of detection paths: the optical path amplification device includes: a second light-emitting device, the distance between the second light-emitting device and the emitting lens group is less than or equal to the distance between the first light-emitting device and the emitting lens group, and the second light-emitting device is not located on the main optical axis of the emitting lens group.

3. The laser radar according to claim 2, characterized in that The second light emitting device is not located on the optical path of the standard detection channel.

4. The laser radar according to claim 1, wherein For each group of detection paths: the optical path amplification device includes: a second photoelectric receiving device, the distance between the second photoelectric receiving device and the receiving lens group is less than or equal to the distance between the first photoelectric receiving device and the receiving lens group, and the second photoelectric receiving device is not located on the main optical axis of the receiving lens group.

5. The laser radar according to claim 4, characterized in that The second photoelectric receiving device is not located on the optical path of the standard detection path.

6. The laser radar according to claim 1, characterized in that For each group of detection paths: the optical path amplification device includes: a third light-emitting device and a third photoelectric receiving device, the distance between the third light-emitting device and the emitting lens group is less than or equal to the distance between the first light-emitting device and the emitting lens group, and the third light-emitting device is not located on the main optical axis of the emitting lens group, the distance between the third photoelectric receiving device and the receiving lens group is less than or equal to the distance between the first photoelectric receiving device and the receiving lens group, and the third photoelectric receiving device is not located on the main optical axis of the receiving lens group.

7. The laser radar according to claim 6, characterized in that The third light emitting device is not located on the optical path of the standard detection path, and / or the third photoelectric receiving device is not located on the optical path of the standard detection path.

8. The laser radar according to any one of claims 1 to 7, characterized in that: For each set of detection paths: a light-emitting control circuit and a receiving circuit are provided; wherein, The light-emitting control circuit is used to generate a driving electrical signal to drive the light-emitting device in the detection path to emit light, and the receiving circuit is used to receive the electrical signal converted by the photoelectric receiving device in the detection path and convert it into an electrical signal that can be detected by the main control unit.

9. A detection method, characterized in that: The laser radar according to any one of claims 1 to 8, comprising: The main control unit obtains the light-emitting time of the light-emitting device in each group of detection paths and the receiving time of the laser echo signal returned by each group of detection paths; The main control unit calculates the obstacle distance according to the light emitting moment and the receiving moment.

10. The detection method according to claim 9, characterized in that: The main control unit obtains the light-emitting time of the light-emitting device in each group of detection paths and the receiving time of the laser echo signal returned by each group of detection paths, including: For each group of detection paths: the main control unit controls the light-emitting devices in the standard detection paths to emit light and records a first light-emitting moment, and regards the first light-emitting moment as the light-emitting moment; The main control unit starts timing at the first light-emitting moment, and when receiving the laser echo signal in the standard detection path before the timing time reaches the first timing threshold, stops timing and records the first receiving moment, and regards the first receiving moment as the receiving moment; When the laser echo signal in the standard detection path is not received when the timing time reaches the first timing threshold, the main control unit controls the light-emitting device in the auxiliary detection path to emit light and records a second light-emitting moment, and regards the second light-emitting moment as the light-emitting moment; The main control unit starts timing at the second light-emitting moment, and when it receives the laser echo signal in the auxiliary detection path before the timing time reaches the second timing threshold, it ends timing and records the second receiving moment, and regards the second receiving moment as the receiving moment.

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