Laser radar and its detection method

Abstract

The application provides a laser radar, comprising a ranging module, a visible light emitting module and a control unit. The ranging module comprises a laser emitting unit configured to emit a probe laser beam to detect a target object; a receiving unit configured to receive a return wave of the probe laser beam reflected by the target object and convert it into an electrical signal; and a processing unit connected to the receiving unit to receive the electrical signal and calculate the distance and / or reflectivity of the target object according to the electrical signal. The visible light emitting module is configured to emit visible light outside the laser radar. The control unit is coupled to the visible light emitting module and configured to control the visible light emitting module to emit visible light under certain conditions.

Description

Technical Field

[0001] This invention relates generally to the field of laser detection technology, and more particularly to a lidar including a visible light emitting module, and a method for detection using the lidar. Background Technology

[0002] With the increasing application of automotive LiDAR, the likelihood of users and pedestrians being exposed to LiDAR laser radiation at close range will continue to rise. For safety reasons, LiDAR products are generally required to meet Level 1 human eye safety standards. As an active measurement method, LiDAR's ranging performance is better the stronger the emitted light radiation; to obtain higher spatial resolution, a denser laser beam needs to be emitted into space. However, Level 1 laser safety standards limit the maximum light radiation that a laser product can emit, thus limiting the detection performance of LiDAR. Nevertheless, safety is a fundamental requirement that LiDAR products must meet.

[0003] The content in the background section is merely technology known to the public and does not necessarily represent existing technology in this field. Summary of the Invention

[0004] In view of at least one deficiency of the prior art, the present invention provides a lidar comprising:

[0005] The ranging module includes:

[0006] A laser emitting unit configured to emit a probe laser beam to detect a target object;

[0007] The receiving unit is configured to receive the echo of the detection laser beam reflected by the target object and convert it into an electrical signal; and

[0008] A processing unit is connected to the receiving unit to receive the electrical signal and calculate the distance and / or reflectivity of the target object based on the electrical signal.

[0009] The visible light emitting module is configured to emit visible light to the outside of the lidar; and

[0010] The control unit is coupled to the visible light emitting module and configured to control the visible light emitting module to emit visible light under certain conditions.

[0011] According to one aspect of the invention, the control unit is configured to control the visible light emitting module to continuously emit visible light during lidar operation.

[0012] According to one aspect of the invention, the control unit is configured to control the visible light emitting module to emit visible light when the energy or power of the probe laser beam emitted by the laser emitting unit is higher than a human eye safety threshold.

[0013] According to one aspect of the invention, the control unit is configured to control the visible light emitting module to emit visible light when the ambient light intensity is lower than a preset light intensity.

[0014] According to one aspect of the invention, the control unit is configured to control the visible light emitting module to emit visible light when the target is within a specific distance range.

[0015] According to one aspect of the invention, the specific distance range can be calculated by comparing the laser energy or power actually received by the human eye with a human eye safety threshold.

[0016] According to one aspect of the invention, the control unit communicates with the ranging module to obtain the distance to the target object, so as to control the visible light emitting module to emit visible light when the target object is within a specific distance range.

[0017] According to one aspect of the invention, the lidar further includes a distance sensor configured to sense the distance to a target object around the lidar, and the control unit communicates with the distance sensor to obtain the distance to the target object in order to control the visible light emitting module to emit visible light when the target object is within a specific distance range.

[0018] According to one aspect of the invention, the control unit obtains the distance of the target from other sensing systems outside the lidar, so as to control the visible light emitting module to emit visible light when the target is within a specific distance range.

[0019] According to one aspect of the invention, the lidar further includes a first scanning module configured to deflect the detection laser beam and visible light incident thereon to the outside of the lidar, wherein the visible light emitted by the visible light emitting module and the laser emitted by the laser emitting unit of the ranging module exit through the same optical path.

[0020] According to one aspect of the invention, the lidar further includes a second scanning module configured to deflect the incident detection laser beam outside the lidar for target detection, wherein the visible light emitted by the visible light emitting module and the laser emitted by the laser emitting unit of the ranging module exit through different optical paths.

[0021] According to one aspect of the invention, the lidar includes a plurality of visible light emitting modules, the emitted light of the plurality of visible light emitting modules corresponding to different vertical fields of view.

[0022] According to one aspect of the invention, the lidar further includes a third scanning module configured to deflect incident visible light outside the lidar and scan within a vertical field of view.

[0023] According to one aspect of the invention, the visible light emitting module and the ranging module are rotatable synchronously about the axis of the lidar.

[0024] According to one aspect of the present invention, the lidar includes a plurality of visible light emitting modules non-rotatably fixed on the lidar, the ranging module is rotatable about the rotation axis of the lidar, the plurality of visible light emitting modules respectively correspond to different horizontal angle ranges of the lidar, and the control unit is configured to sequentially control the corresponding visible light emitting modules to emit visible light when the ranging module rotates.

[0025] According to one aspect of the invention, the visible light emitting module is located outside the lidar window or photomask.

[0026] According to one aspect of the invention, the visible light emitting module is located inside the lidar and emits visible light to the outside of the lidar through a window or a photomask.

[0027] The present invention also provides a method for detection using the lidar described above, comprising:

[0028] S101: Target detection is performed by emitting a detection laser beam through the ranging module of the lidar;

[0029] S102: Control the visible light emitting module of the lidar to emit visible light under certain conditions.

[0030] According to one aspect of the invention, step S102 includes:

[0031] The visible light emitting module is controlled to continuously emit visible light during the operation of the lidar.

[0032] According to one aspect of the invention, step S102 includes:

[0033] The visible light emission module is controlled to emit visible light when the energy or power of the probe laser beam emitted by the laser emission unit is higher than the safety threshold for the human eye.

[0034] According to one aspect of the invention, step S102 includes:

[0035] The visible light emitting module is controlled to emit visible light when the ambient light intensity is lower than the preset light intensity.

[0036] According to one aspect of the invention, step S102 includes:

[0037] When the target is within a specific distance range, the visible light emitting module is controlled to emit visible light.

[0038] According to one aspect of the invention, it further includes one or more of the following steps:

[0039] The distance to the target object is obtained from the ranging module;

[0040] The distance to the target object is obtained from the distance sensor; and

[0041] The distance to the target is obtained from other sensing systems outside the lidar.

[0042] A preferred embodiment of the present invention provides a lidar including a visible light emitting module. Under the control of a control unit, this visible light emitting module emits visible light under one or more of the following conditions: continuous emission; the energy or power of the detection laser beam exceeds a human eye safety threshold; the ambient light intensity is lower than a preset light intensity; and the target object is within a specific distance range. By emitting visible light to constrict the observer's pupils or trigger a stress avoidance response, the lidar's emission power is increased while ensuring human eye safety, thereby improving its detection performance. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0044] Figure 1 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0045] Figure 2 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0046] Figure 3 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0047] Figure 4 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0048] Figure 5 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0049] Figure 6 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0050] Figure 7 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0051] Figure 8A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0052] Figure 9 A lidar according to a preferred embodiment of the present invention is illustrated schematically;

[0053] Figure 10A The diagram schematically illustrates the relative positions of the visible light emitting module and the window panel according to a preferred embodiment of the present invention;

[0054] Figure 10B The diagram schematically illustrates the relative positions of the visible light emitting module and the photomask according to a preferred embodiment of the present invention;

[0055] Figure 11A The diagram schematically illustrates the relative positions of the visible light emitting module and the window panel according to a preferred embodiment of the present invention;

[0056] Figure 11B The diagram schematically illustrates the relative positions of the visible light emitting module and the photomask according to a preferred embodiment of the present invention;

[0057] Figure 12 A detection method for a lidar according to a preferred embodiment of the present invention is shown. Detailed Implementation

[0058] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0062] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0063] The embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0064] According to a preferred embodiment of the present invention, such as Figure 1As shown, the present invention provides a lidar 10, including a ranging module 11, a visible light emitting module 12, and a control unit 13. The ranging module 11 is used to measure the distance to a target by emitting a detection laser beam, and includes a laser emitting unit 110, a receiving unit 111, and a processing unit 112. The laser emitting unit 110 includes one or more lasers configured to emit a detection laser beam to detect a target; the receiving unit 111 is configured to receive the echo of the detection laser beam reflected by the target and convert it into an electrical signal; the processing unit 112 is connected to the receiving unit 111 to receive the electrical signal and calculate the distance and / or reflectivity of the target based on the electrical signal. The visible light emitting module 12 is configured to emit visible light to the outside of the lidar. The control unit 13 is coupled to the visible light emitting module 12 and configured to control the visible light emitting module 12 to emit visible light under certain conditions.

[0065] As mentioned earlier, with the increasingly widespread application of lidar, the likelihood of people being exposed to its laser radiation at close range is increasing. Furthermore, as an active measurement method, lidar's detection performance is superior when the emitted light radiation is stronger and denser. Therefore, to achieve greater detection distance and higher spatial resolution, higher power and denser lasers are required. Additionally, the lasers used by lidar are often near-infrared light, invisible to human vision and unable to elicit eye adjustments. Therefore, if the laser power is too high, it is possible that damage to the eyes may occur unnoticed by those nearby. Consequently, the Level 1 laser product standard in laser safety standards limits the maximum light radiation emitted by laser products, thereby restricting the detection performance of lidar.

[0066] The inventors of this application have conceived of using visible light to stimulate pupillary adjustment or trigger an avoidance response in the eye. Utilizing the characteristic that the pupillary sphincter muscle in the iris can control the contraction and dilation of the pupil when exposed to ambient light, visible light of a certain intensity can cause the observer's pupil to constrict or trigger an avoidance response, thereby avoiding laser safety risks and improving the detection capability of the lidar while ensuring user safety. When a person is suddenly exposed to strong visible light, the pupil constricts rapidly, reducing its diameter. By utilizing this characteristic of pupil constriction or avoidance response, it is possible to keep the observer's pupil diameter small during lidar ranging or when an object is within the lidar's safety risk range. This reduces the laser energy entering the observer's eye, thus ensuring the safety of the lidar in foreseeable usage scenarios. In other words, even if the lidar's emission power is high, because the observer's pupil diameter is small, only a small portion of the laser energy enters the pupil compared to a normal pupil diameter, thus ensuring eye safety.

[0067] The control unit 13 can control the visible light emitting module 12 to emit visible light according to various strategies. These are described in detail below.

[0068] According to a preferred embodiment of the present invention, the control unit 13 is configured to control the visible light emitting module 12 to continuously emit visible light during the operation of the lidar 10. Continuous emission of visible light during lidar ranging causes the pupils of observers around the lidar to constrict, ensuring that the near-infrared laser light entering the constricted pupils is within the threshold of a first-level laser product, or triggering an avoidance reaction that causes the person to subconsciously look away. By controlling the visible light emitting module 12 to continuously emit visible light during the operation of the lidar 10, it is possible to ensure that the pupils of people around the lidar are in a constricted state. The visible light emitted by the visible light emitting module 12 is preferably a continuous wave, and preferably light emitted directly without collimation to cover a wider field of view.

[0069] According to a preferred embodiment of the present invention, the control unit 13 is configured to control the visible light emitting module 12 to emit visible light when the energy or power of the detection laser beam emitted by the laser emitting unit 110 is higher than the safety threshold for the human eye. The safety threshold of the lidar can be pre-calculated and set. For example, the safety threshold of the laser product can be calculated according to laser safety standards (such as IEC 60825-1:2014), and the calculation process needs to consider the luminescence characteristics of the laser product itself. Laser products are classified from Class 1 to Class 4, with Class 1 laser products being safe and harmless. The aforementioned safety threshold for the human eye refers to the Class 1 safety threshold. Taking a pulsed lidar as an example, the safety threshold calculation needs to consider not only the size of the beam image on the retina and the proportion of the beam entering the pupil, but also the spatial distribution and temporal characteristics of the laser pulses. These factors are reflected in different parameters during threshold calculation. Furthermore, for laser pulses, recurring laser pulses are also affected by a correction factor; the threshold decreases as the number of pulses increases over a period of time, meaning that long-term pulses produce a superposition effect that lowers the threshold. Furthermore, different lasers in a lidar system may correspond to different fields of view and detection distances, and therefore have different emission powers or energies. During continuous detection, the emission power or energy of the currently emitting laser is compared with a preset human eye safety threshold. If it is higher than the human eye safety threshold, the control unit 13 controls the visible light emitting module 12 to emit visible light to stimulate the pupils of surrounding people to constrict and avoid damage from the laser. If it is lower than the human eye safety threshold, the control unit 13 does not need to control the visible light emitting module 12 to emit visible light, because the emission intensity at this time is safe and will not cause damage to the human eye.

[0070] According to a preferred embodiment of the present invention, the control unit 13 is configured to control the visible light emitting module 12 to emit visible light when the ambient light intensity is lower than a preset light intensity. When the ambient light intensity is high, the diameter of the human eye pupil is usually small, and even if the luminous power of the lidar is high, it will not cause damage to the human eye. However, when the ambient light intensity is low, the diameter of the human eye pupil is usually large in order to see the surrounding environment clearly, and the laser emitted by the lidar is more likely to cause damage to the human eye. The threshold specified in the laser safety standard is the actual energy or power entering the pupil. The current laser safety standard often assumes that the pupil size is 7mm, which is the maximum diameter that the pupil can reach in the dark under normal circumstances in a population. Under normal daylight conditions, the pupil is usually only 2-3mm. If the pupil opening size decreases, the light energy or power entering the eyeball and being absorbed by the eye tissue decreases, and the safety threshold of laser energy or power calculated according to the laser safety standard increases. Therefore, the lidar can emit stronger laser light to achieve better detection capabilities. For example, if the safety threshold calculated after pupil size decreases is the first threshold, and the safety threshold calculated when pupil size is 7mm is the second threshold, then the first threshold is greater than the second threshold. Ambient light intensity can be calculated based on one or more of the current date, time, and weather. Alternatively, the intensity of ambient light can be directly measured. For example, in the emission gap of the laser emitting unit 110 of the lidar, the output of the receiving unit 111 can characterize the intensity of ambient light. The lidar can pre-store the relationship between ambient light intensity and pupil size, and can estimate the pupil size using the actual ambient light intensity. Then, the estimated pupil size is used as a factor to determine whether the laser power exceeds the safety threshold. For example, when the ambient light intensity is high, the estimated pupil size is 2mm, and the lidar can emit laser according to the first threshold. When the ambient light intensity decreases, the pupil opening increases, and the light energy entering the eyeball and being absorbed by the eye tissue increases. At this time, visible light is emitted, causing the observer's pupil to constrict or triggering a stress avoidance response, ensuring the safety of lidar use.

[0071] According to a preferred embodiment of the present invention, the control unit 13 is configured to control the visible light emitting module 12 to emit visible light when the target object is within a specific distance range. Laser light attenuates during propagation; therefore, even with a high-power laser, the intensity of the emitted laser light will decrease after traveling a certain distance, having virtually no impact on the human eye. Thus, when the observer is within a specific distance range (the specific distance is greater than or equal to the risk distance), the lidar can actively emit visible light, causing the observer's pupil to constrict. Within the risk distance range, the near-infrared laser light entering the constricted pupil is within the threshold of a Class I laser product, or triggers a stress avoidance response that subconsciously moves the eyes away. Due to the cumulative damage effect of the laser pulse, when an object is detected within the risk distance, visible light is rapidly emitted, causing the observer's pupil to constrict. The light radiation received by the observer in both short and long periods is within the safety threshold of a Class I laser product, or triggers a stress avoidance response that subconsciously moves the eyes away. The risk distance is calculated by comparing the actual laser energy or power received by the human eye with the safety threshold for the human eye. The risk distance here is calculated based on a pupil size of 7mm as defined in laser safety standards. Within this risk distance, the actual laser energy or power received by the human eye exceeds the eye safety threshold; outside this risk distance, the actual laser energy or power received by the human eye is below the eye safety threshold. Specific distances may be the same as the risk distance, or greater than the risk distance according to system requirements.

[0072] As will be readily understood by those skilled in the art, the control unit 13 can control the visible light emitting module 12 to emit visible light based on one or more of the following factors: the energy or power of the probe laser beam emitted by the laser emitting unit 110, the ambient light intensity, and a specific distance range.

[0073] Regarding the detection of the distance to the target object, according to a preferred embodiment of the present invention, the control unit 13 communicates with the ranging module 11 to obtain the distance to the target object, so as to control the visible light emitting module 12 to emit visible light when the target object is within a specific distance range.

[0074] Alternatively, or alternatively, according to a preferred embodiment of the present invention, such as Figure 2 As shown, the lidar 10 also includes a distance sensor 14, which is configured to sense the distance to targets around the lidar 10. The control unit 13 communicates with the distance sensor 14 to obtain the distance to the targets, so as to control the visible light emitting module 12 to emit visible light when the targets are within a specific distance range. The distance sensor 14 includes, for example, one or more of ultrasonic radar, proximity sensors, etc.

[0075] According to a preferred embodiment of the present invention, such as Figure 3As shown, the control unit 10 obtains the distance to the target from other sensing systems 15 outside the lidar 10, so as to control the visible light emitting module 12 to emit visible light when the target is within a specific distance range. The other sensing systems 15 can transmit the distance information to the lidar 10 via wired or wireless transmission.

[0076] According to a preferred embodiment of the present invention, such as Figure 4 As shown, the lidar 10 also includes a first scanning module 16, configured to deflect the incident detection laser beam and visible light to the outside of the lidar, and to cover a certain range of field of view through the scanning action of the first scanning module 16. The visible light emitted by the visible light emitting module 12 and the detection laser beam emitted by the laser emitting unit 110 of the ranging module 11 exit through the same optical path. In the returning optical path, for example, a filter is usually placed on the receiving lens or in front of the detector. The wavelength of the visible light is outside the passband of the filter, so that the visible light does not return to the detector. Figure 4 The diagram illustrates one implementation of a scanning device, in which visible light emitted by the visible light emitting module 12 and infrared laser emitted by the ranging module 11 are scanned in one or two dimensions via a first scanning module 16. The first scanning module 16 can be a galvanometer, a tilting mirror, a multi-faceted rotating mirror, or the like. Figure 5 A specific implementation structure of a scanning device using a galvanometer 16-1 is shown. This structure also includes a beam-splitting module 17, which may be, for example, a semi-transparent, semi-reflective mirror. Figure 5 As shown, the infrared laser 110 of the ranging module 11 emits infrared laser light, and the visible light emitting module 12, controlled by the control unit 13, emits visible light under certain conditions. Both emit visible light through the beam splitter 17 and the galvanometer 16 before being emitted into the outside world. The echo reflected by external objects is then received by the detector 111 of the ranging module 11 after passing through the galvanometer 16 and the beam splitter 17. The visible light portion of the echo is filtered out before reaching the detector 111. The visible light emitting module 12 may include, for example, one or more of a light-emitting diode (LED) or a laser diode (LD).

[0077] According to a preferred embodiment of the present invention, such as Figure 6 As shown, the lidar 10 also includes a second scanning module 18, configured to deflect the incident detection laser beam outside the lidar for target detection, and to cover a certain range of field of view through the scanning action of the second scanning module 18. Preferably, as Figure 6 As shown, the visible light emitted by the visible light emitting module 12 and the detection laser beam emitted by the laser emitting unit 110 of the ranging module 11 are emitted through different optical paths to reduce interference with ranging. Figure 6The implementation structure of the scanning device is shown. The infrared laser emitted by the ranging module 11 is scanned in one or two dimensions by the second scanning module 18. The visible light emitted by the visible light emitting module 12 is emitted directly without passing through the second scanning module 18.

[0078] According to a preferred embodiment of the present invention, Figure 7 Another specific implementation of a scanning device using a galvanometer 18-1 is shown, which also includes a beam splitter module 17, which may be, for example, a semi-transparent mirror. Figure 7 As shown, the infrared laser 110 of the ranging module 11 emits infrared laser light, which is then emitted to the outside after passing through the beam splitter 17 and the galvanometer 18-1. The echo reflected by the external object is received by the detector 111 of the ranging module 11 after passing through the galvanometer 18-1 and the beam splitter 17. The visible light emitting module 12 is controlled by the control unit 13 to emit visible light under certain conditions. The visible light emitted by the visible light emitting module 12 is emitted directly without passing through the galvanometer 18-1.

[0079] In another preferred embodiment of the present invention, the lidar 10 includes a plurality of visible light emitting modules 12, the emitted light of the plurality of visible light emitting modules 12 corresponding to different vertical and / or horizontal fields of view. By providing a plurality of visible light emitting modules 12, the field of view scanned by the second scanning module 18 can be covered.

[0080] According to a preferred embodiment of the present invention, such as Figure 8 As shown, the lidar 10 also includes a third scanning module 19, configured to deflect incident visible light outside the lidar and scan within a vertical and / or horizontal field of view. The third scanning module 19, for example, scans the visible light emitted by the visible light emitting module 12 in the vertical direction, ensuring that the eyes of observers of different heights are illuminated by visible light. The third scanning module 19 can also scan the visible light emitted by the visible light emitting module 12 in the horizontal direction, ensuring that the eyes of observers within a certain horizontal field of view are illuminated by visible light. The field of view scanned by the third scanning module 19 may overlap, for example, with, the field of view scanned by the second scanning module 18, or partially overlap. Furthermore, the scanning angle of the visible light and the scanning angle of the laser preferably have a predetermined deviation.

[0081] According to a preferred embodiment of the present invention, such as Figure 9As shown, the visible light emitting module 12 and the ranging module 11 can rotate synchronously around the rotation axis OO of the lidar 10. The laser emitting unit 110 and the receiving unit 111 of the ranging module 11 rotate 360° around the rotation axis OO, and the visible light emitting module 12 and the ranging module 11 rotate synchronously around the rotation axis OO (i.e., maintaining the same horizontal field of view). The visible light emitting module 12 is controlled by the control unit 13 to emit visible light under certain conditions, thereby ensuring the safety of human eyes within the current detection field of view of the lidar.

[0082] According to a preferred embodiment of the present invention, the ranging module 11 is rotatable around the rotation axis OO of the lidar, while multiple visible light emitting modules 12 are non-rotatably fixed on the lidar, each corresponding to a different horizontal field of view of the lidar. The control unit 13 is configured to sequentially control the corresponding visible light emitting modules 12 to emit visible light when the ranging module 11 rotates. Figure 10B and 11B As shown, multiple visible light emitting modules 12 are mounted on the base of the lidar and are non-rotatable. The laser emitting unit 110 and receiving unit 111 of the ranging module 11 rotate 360° around the axis of rotation, while the multiple visible light emitting modules 12 are distributed along the lidar 10 at 360° (without rotating). During the operation of the ranging module 11, the visible light emitting modules 12 are controlled by the control unit 13 to emit visible light under certain conditions. For example, when the ranging module 11 rotates to a certain angle, the visible light emitting module 12 corresponding to the current horizontal angle is controlled to emit visible light under certain conditions. At this angle, the visible light emitting module 12 can emit light earlier than the ranging module 11 (based on data from the distance sensor or other sensing system), serving as an early warning function, causing the observer's pupils to constrict or triggering a stress avoidance response.

[0083] According to a preferred embodiment of the present invention, such as Figure 10A and 10B As shown, the visible light emitting module 12 can be located outside the lidar 10, for example, outside the window 21 or the photomask 20. Alternatively, according to a preferred embodiment of the invention, such as Figure 11A and 11B As shown, the visible light emitting module 12 can be located inside the lidar 10 and emits visible light to the outside of the lidar 10 through the window 21 or the photomask 20. When the visible light emitting module 12 is located inside the lidar 10, it is necessary to select a matching window 21 / photomask 20 for emission.

[0084] Similar to the arrangement of the visible light emitting module 12 described above, the aforementioned distance sensor 14 can also be arranged in a rotatable or non-rotatable manner. For example, for a scanning lidar, the distance sensor 14 is arranged on the front panel of the lidar; for a rotating lidar, the distance sensor 14 can be arranged non-rotatably on the top or base of the lidar, or it can rotate synchronously with the ranging module 11.

[0085] According to a preferred embodiment of the present invention, such as Figure 12 As shown, the present invention also provides a method 100 for detection using the lidar 10 described above, comprising:

[0086] In step S101, the target object is detected by emitting a detection laser beam through the ranging module of the lidar.

[0087] In step S102, the visible light emitting module of the lidar is controlled to emit visible light under certain conditions.

[0088] According to a preferred embodiment of the present invention, step S102 includes one or more of the following steps:

[0089] The visible light emitting module is controlled to continuously emit visible light during the operation of the lidar;

[0090] The visible light emitting module is controlled to emit visible light when the energy or power of the detection laser beam emitted by the laser emitting unit is higher than the safety threshold for the human eye;

[0091] The visible light emitting module is controlled to emit visible light when the ambient light intensity is lower than a preset light intensity; and

[0092] When the target is within a specific distance range, the visible light emitting module is controlled to emit visible light.

[0093] According to a preferred embodiment of the present invention, the detection method 100 further includes one or more of the following steps:

[0094] The distance to the target object is obtained from the ranging module;

[0095] The distance to the target object is obtained from the distance sensor; and

[0096] The distance to the target is obtained from other sensing systems outside the lidar.

[0097] A preferred embodiment of the present invention provides a lidar including a visible light emitting module. Under the control of a control unit, this visible light emitting module emits visible light under one or more of the following conditions: continuous emission; the energy or power of the detection laser beam exceeds a human eye safety threshold; the ambient light intensity is lower than a preset light intensity; and the target object is within a specific distance range. By emitting visible light to constrict the observer's pupils or trigger a stress avoidance response, the lidar's emission power is increased while ensuring human eye safety, thereby improving its detection performance.

[0098] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1.A lidar, comprising: a ranging module, comprising: a laser emitting unit configured to emit a probe laser beam to probe a target object; a receiving unit configured to receive a return of the probe laser beam reflected by the target object and convert the return into an electrical signal; and a processing unit connected to the receiving unit to receive the electrical signal and calculate a distance and / or reflectivity of the target object and determine a light intensity of ambient light according to the electrical signal; a visible light emitting module configured to emit visible light outside the lidar; and a control unit coupled to the visible light emitting module and configured to control the visible light emitting module to emit visible light when the light intensity is lower than a preset light intensity and when the target object enters a preset distance range during a continuous probing by the ranging module, wherein an energy or power of the probe laser beam is higher than a human eye safety threshold in the preset distance range. 2.The lidar of claim 1, wherein the control unit is configured to control the visible light emitting module to emit visible light when the target object is in a specific distance range. 3.The lidar of claim 2, wherein the specific distance range is calculated according to a comparison between an actual received laser energy or power of a human eye and the human eye safety threshold. 4.The lidar of claim 2 or 3, wherein the control unit communicates with the ranging module to obtain the distance of the target object to control the visible light emitting module to emit visible light when the target object is in the specific distance range. 5.The lidar of claim 2 or 3, further comprising a distance sensor configured to sense the distance of a target object around the lidar, and the control unit communicates with the distance sensor to obtain the distance of the target object to control the visible light emitting module to emit visible light when the target object is in the specific distance range. 6.The lidar of claim 2 or 3, wherein the control unit obtains the distance of the target object from other perception systems outside the lidar to control the visible light emitting module to emit visible light when the target object is in the specific distance range. 7.The lidar of any one of claims 1-3, further comprising a first scanning module configured to deflect the probe laser beam and the visible light incident thereon to outside the lidar, wherein the visible light emitted by the visible light emitting module and the laser emitted by the laser emitting unit of the ranging module exit through the same optical path. 8.The lidar of any one of claims 1-3, further comprising a second scanning module configured to deflect the probe laser beam incident thereon to outside the lidar for target object probing, wherein the visible light emitted by the visible light emitting module and the laser emitted by the laser emitting unit of the ranging module exit through different optical paths. 9.The lidar of claim 8, wherein the lidar comprises a plurality of visible light emitting modules, and the exit light of the plurality of visible light emitting modules corresponds to different vertical fields of view. 10.The lidar of claim 8, further comprising a third scanning module configured to deflect the visible light incident thereon outside the lidar and scan in a vertical field of view range. 11.The lidar of any one of claims 1-3, wherein the visible light emitting module and the ranging module are synchronously rotatable around a rotation axis of the lidar. 12.The lidar of any one of claims 1-3, wherein the lidar comprises a plurality of visible light emitting modules non-rotatably fixed on the lidar, the ranging module is rotatable around a rotation axis of the lidar, the plurality of visible light emitting modules correspond to different horizontal angle ranges of the lidar respectively, and the control unit is configured to control the corresponding visible light emitting module to emit visible light in turn when the ranging module rotates. 13.The lidar of any one of claims 1-3, wherein the visible light emitting module is located outside a window sheet or a light cover of the lidar. 14.The lidar of any one of claims 1-3, wherein the visible light emitting module is located inside the lidar and emits visible light to outside the lidar through a window sheet or a light cover. 15.A detection method using the lidar of any one of claims 1-14, comprising: S101:emitting a detection laser beam by a ranging module of the lidar to detect a target object and determine a light intensity of ambient light; S102:controlling a visible light emitting module of the lidar to emit visible light when the target object enters a preset distance range and the light intensity is lower than a preset light intensity during the continuous detection by the ranging module; wherein the energy or power of the detection laser beam is higher than a human eye safety threshold in the preset distance range. 16.The detection method of claim 15, wherein the step S102 comprises: controlling the visible light emitting module to emit visible light when the target object is in a specific distance range. 17.The detection method of claim 16, further comprising one or more of the following steps: obtaining the distance of the target object from the ranging module; obtaining the distance of the target object from a distance sensor; and obtaining the distance of the target object from other perception systems outside the lidar.

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