Laser radar architecture and control method and device

Abstract

The invention discloses a laser radar architecture and a control method and device, and relates to the technical field of laser radar detection, and the laser radar architecture comprises a transmitting module and a receiving module. The transmitting module comprises a scanning unit, and the scanning unit comprises a point light source and a two-dimensional liquid crystal unit corresponding to the point light source; light rays emitted by the point light sources are reflected into the environment through the corresponding two-dimensional liquid crystal units and are used for scanning the environment; the receiving module is used for receiving reflected light returned from the environment so as to form a scanning result of the view field area. By changing the voltage applied to the two dimensions of the two-dimensional liquid crystal unit, the liquid crystal can be controlled to generate phase deflection in the two dimensions, so that the range and the position of a scanned view field can be flexibly adjusted.

Description

Technical Field

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

[0002] With the rapid development of technologies such as autonomous driving and robot navigation, LiDAR, as an important sensor, plays an irreplaceable role in environmental perception and positioning. Compared with other radars, Flash solid-state LiDAR has the advantages of high reliability, small size and low cost.

[0003] LCM (light control metasurface) is a kind of beam angle scanning that uses metasurface technology. It has the advantages of "true solid-state, zero inertia" beam steering technology, large field of view, high control accuracy, simple peripheral circuit, low cost, high reliability, etc. It has broad application prospects in solid-state lidar.

[0004] However, current research on the application of LCM in LiDAR scanning components is relatively simple, without achieving a true architecture, and without solving the defects of LCM applications in LiDAR products. Summary of the invention

[0005] In view of this, the present application provides a laser radar architecture and a control method and device, the main purpose of which is to build a solid-state laser radar architecture with LCM as a scanning component and solve the defects in practical applications.

[0006] According to a first aspect of the present application, a laser radar architecture is provided, comprising a transmitting module and a receiving module, wherein the transmitting module comprises a scanning unit, wherein the scanning unit comprises a point light source and a two-dimensional liquid crystal unit corresponding to the point light source; light emitted by the point light source is reflected into an environment through the corresponding two-dimensional liquid crystal unit, so as to scan the environment;

[0007] The receiving module is used to receive reflected light returned from the environment to form a scanning result of the field of view area.

[0008] Optionally, the transmitting module includes a beam shaping unit;

[0009] The beam shaping unit is used to homogenize and expand the reflected light beam reflected by the two-dimensional liquid crystal unit to obtain a shaped light beam, and reflect the shaped light beam into the environment.

[0010] According to a second aspect of the present application, a control method of a laser radar is provided, and the control method is applied to the laser radar architecture in the first aspect, and the control method includes:

[0011] Dividing the field of view area to obtain multiple sub-fields of view;

[0012] The point light source is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to a scanning sequence, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple sub-fields of view in sequence.

[0013] Optionally, the multiple sub-fields of view are divided into multiple sub-field of view groups according to a scanning sequence; the number of sub-fields of view included in each sub-field of view group is the same as the number of scanning units; and each sub-field of view included in each sub-field of view group corresponds to one scanning unit;

[0014] Then, the method further comprises:

[0015] For each scanning unit, the two-dimensional liquid crystal unit is controlled to deform at every first preset time interval so that the light emitted by the point light source of the scanning unit switches from a sub-field of view in the previous sub-field of view group to a sub-field of view in the next sub-field of view group; the first preset time interval is greater than the response time of the two-dimensional liquid crystal unit.

[0016] Optionally, the method further comprises:

[0017] For each sub-field of view group, between the pulse intervals of two emission pulses of the point light source of each scanning unit, the point light sources of other scanning units are controlled to emit a pulse, and the light emission time of the point light source of each scanning unit is different.

[0018] Optionally, the method further comprises:

[0019] The two-dimensional liquid crystal unit corresponding to each point light source is controlled to generate the first phase to scan the current sub-field group. The scanning process is divided into three stages:

[0020] The first stage: controlling the point light sources of all scanning units to emit a first number of pulses in sequence;

[0021] The second stage: controlling the point light sources of all scanning units to emit a second number of pulses alternately;

[0022] The third stage: controlling the point light sources of all scanning units to emit a third number of pulses in sequence;

[0023] After the current sub-viewing field group is scanned, the two-dimensional liquid crystal unit corresponding to each point light source is controlled to generate a second phase, so that the scanning process switches from the current sub-viewing field group to the next sub-viewing field group.

[0024] Optionally, the transmitting module includes a first scanning unit and a second scanning unit, and the method further includes:

[0025] The full field of view area is divided to obtain a plurality of first sub-fields of view; the ROI area is divided to obtain a plurality of second sub-fields of view; wherein the ROI area is a part of the full field of view area;

[0026] For the full field of view, the point light source of the first scanning unit is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to the scanning timing, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple first sub-fields of view;

[0027] For the ROI area, control the point light source of the second scanning unit to emit light, and control the two-dimensional liquid crystal unit corresponding to the point light source to generate multiple deformations in sequence according to the scanning timing, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple second sub-fields of view;

[0028] According to the scanning results of the first sub-field of view and the second sub-field of view, point cloud data fusion of the ROI area is performed.

[0029] Optionally, the method further comprises:

[0030] Selecting a plurality of sub-fields of view from the first sub-field of view as the second sub-field of view;

[0031] Then, the step of fusing the point cloud data of the ROI area according to the scanning results of the first sub-field of view and the second sub-field of view includes:

[0032] For each second sub-field of view, fusing the scan data of the second sub-field of view scanned by the first scanning unit with the scan data of the second sub-field of view scanned by the second scanning unit to obtain sub-region fused point cloud data;

[0033] The fused point cloud data of all sub-regions of the second sub-field of view are spliced ​​to obtain the fused point cloud data of the ROI region.

[0034] By means of the above technical solution, the present application provides a laser radar architecture, control method and device. By changing the voltage applied to the two dimensions of the two-dimensional liquid crystal unit, the phase deflection of the liquid crystal in two dimensions can be controlled. Therefore, the range and position of the light beam reflected from the two-dimensional liquid crystal unit can be flexibly adjusted, thereby flexibly adjusting the scanned field of view range and position.

[0035] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0037] Figure 1 A laser radar architecture provided by an embodiment of the present application is shown;

[0038] Figure 2 Another laser radar architecture provided by an embodiment of the present application is shown;

[0039] Figure 3 A schematic diagram of a control method of a laser radar provided in an embodiment of the present application is shown;

[0040] Figure 4 A schematic diagram of a control device of a laser radar architecture provided in an embodiment of the present application is shown;

[0041] Figure 5 An example diagram of forming a scanning result within an acceptable pixel range provided by an embodiment of the present application is shown;

[0042] Figure 6 Another example diagram of forming a scanning result within an acceptable pixel range provided by an embodiment of the present application is shown;

[0043] Figure 7 An example diagram of a sub-field of view provided by an embodiment of the present application is shown;

[0044] Figure 8 An example diagram of a first sub-field of view and a second sub-field of view provided by an embodiment of the present application is shown;

[0045] Fig. 9 An example diagram showing a plurality of scanning units scanning a sub-field of view provided by an embodiment of the present application is shown;

[0046] Fig.10 An example diagram showing a sub-field of view scanned in a cross-time sequence by multiple scanning units provided in an embodiment of the present application is shown;

[0047] Fig.11 An example diagram of a sub-field-of-view group scanning timing provided by an embodiment of the present application is shown;

[0048] Fig.12 An example diagram showing a row of distorted positions corresponding to a row of sub-fields of view after calibration provided by an embodiment of the present application is shown;

[0049] Fig.13 A computer device provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0050] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0051] The present application embodiment provides a laser radar architecture, such as Figure 1 As shown, the laser radar architecture includes a transmitting module 101 and a receiving module 102: the transmitting module 101 includes a scanning unit, and the scanning unit includes a point light source and a two-dimensional liquid crystal unit corresponding to the point light source; the light emitted by the point light source is reflected into the environment through the corresponding two-dimensional liquid crystal unit to scan the environment; the receiving module 102 is used to receive the reflected light returned from the environment to form a scanning result of the field of view area.

[0052] For Transmitter Module 101:

[0053] In actual application, the two-dimensional liquid crystal unit uses a 2D LCM device. The way LCM achieves angle deflection is relatively simple. It only needs to apply different voltages to the unit, and the liquid crystal unit will present different deflection phases, thus forming a metasurface. For a 2D LCM device, it only needs to apply different voltages in two dimensions, and the liquid crystal will perform phase deflection in two dimensions, thereby achieving two-dimensional light direction modulation, and the scanning position and range can be flexibly adjusted in two dimensions.

[0054] The existing technology uses a line light source + rotating mirror to scan. The light beam emitted by the line light source will form a line light spot after being reflected by the rotating mirror. The position of a rotating mirror corresponds to a row or column of scanning data. As the position of the rotating mirror changes, the scanning position of a row or column changes continuously, thereby completing the scanning of the full field of view. Compared with the scanning method of a line light source + rotating mirror, the scanning method of a point light source + a two-dimensional liquid crystal unit changes the emission angle of the reflected light formed by the point light source incident on the liquid crystal unit by changing the voltage in two directions applied to the two-dimensional liquid crystal unit, so that the emitted light can move in two directions to complete the two-dimensional scanning of the full field of view. The adjustment flexibility is higher, and it can be controlled to stay at a certain scanning position, while the rotating mirror needs to scan continuously; no calibration and angle feedback are required, and the angle accuracy is high. In addition, the two-dimensional liquid crystal unit is a solid-state device without a mechanical structure, with high reliability, and can achieve large field of view angle scanning.

[0055] For the receiving module 102:

[0056] In actual application, the reflected light returned from the environment can form a scanning result of the field of view area only after being received by the photosensitive pixels of the receiving module 102. The receiving module 102 can adopt a SPAD array, which includes a plurality of SPAD receiving pixels.

[0057] The photosensitive pixels have a maximum range limit. If the range exceeds this maximum range, they cannot be received and energy is wasted. Therefore, the scanning results of the field of view area are also limited by the maximum range. This maximum range is the receivable pixel range. For example, the field of view angle range corresponding to the receivable pixel is 144°*108°. Accordingly, the flexible adjustment of the scanning result range and position must be within the receivable pixel range of 144°*108°. Figure 5 As shown, the SPAD in the figure represents the receivable pixel range, the TX1 scanning position 1 in the figure represents the field of view range of the transmitting module 1 scanning in the space, and the TX1 scanning position 2 refers to the same transmitting module. After fine-tuning within the receivable pixel range, the scanning range changes. However, whether it is TX1 scanning position 1 or TX1 scanning position 2, it does not exceed the receivable pixel range SPAD. Of course, the scanning range can also be enlarged or reduced, such as Figure 6 The change of the scanning range is achieved by adjusting the phase of the two-bit liquid crystal unit in the emission module.

[0058] In actual application, if the scanning unit scans the full field of view area in the environment, the receiving module 102 forms a scanning result of the full field of view area in the receivable pixel area accordingly. If the scanning unit scans the ROI area (Region of Interest) in the environment, the receiving module 102 forms a scanning result of the ROI area in the receivable pixel area accordingly. The ROI area is a specific area that needs to be focused on and detected, so that more detailed information can be studied.

[0059] In an optional implementation scheme, the transmitting module 101 includes a first scanning unit and a second scanning unit. Both the first scanning unit and the second scanning unit include a point light source and a two-dimensional liquid crystal unit corresponding to the point light source. The difference is that the two-dimensional liquid crystal unit of the first scanning unit reflects to the full field of view area in the environment, which is used to scan the full field of view area, and the two-dimensional liquid crystal unit of the second scanning unit reflects to the ROI area in the environment, which is used to scan the ROI area. The first scanning unit and the second scanning unit have the same structure and working mode, and the difference lies in the spatial range of the scan, that is, the voltage applied to the two-dimensional liquid crystal unit and the phase change range of the two-dimensional liquid crystal generated thereby. Correspondingly, the receiving module 102 receives the scanning result corresponding to the first scanning unit in the full field of view area (except the ROI area), and receives the common scanning result of the first scanning unit and the second scanning unit in the ROI area.

[0060] In another alternative embodiment, Figure 2 As shown, the transmitting module 101 includes a beam shaping unit; the beam shaping unit is used to homogenize and expand the reflected light beam reflected by the two-dimensional liquid crystal unit to obtain a shaped light beam, and reflect the shaped light beam into the environment.

[0061] In actual application, the role of beam expansion is to diffuse the light beam, and the role of light homogenization is to make the diffused light beam uniform. Compared with the reflected light beam, the scanning range of the shaped light beam is expanded, and the energy within the scanning range is uniform, which improves the scanning efficiency.

[0062] The laser radar architecture provided in the embodiment of the present application includes a transmitting module and a receiving module, wherein the transmitting module includes a scanning unit, wherein the scanning unit includes a point light source and a two-dimensional liquid crystal unit corresponding to the point light source; the light emitted by the point light source is reflected into the environment through the corresponding two-dimensional liquid crystal unit, and is used to scan the environment; the receiving module is used to receive the reflected light returned from the environment to form a scanning result of the field of view area. Since the voltage applied to the two dimensions of the two-dimensional liquid crystal unit is changed, the phase deflection of the liquid crystal in the two dimensions can be controlled, therefore, the range and position of the light beam reflected from the two-dimensional liquid crystal unit can be flexibly adjusted, thereby flexibly adjusting the range and position of the scanned field of view.

[0063] Further, as a refinement and expansion of the specific implementation of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, the embodiment of the present application provides a control method of a laser radar, which is applied to the above laser radar architecture, such as Figure 3 As shown, the method includes:

[0064] 201. Divide the field of view area to obtain multiple sub-fields of view.

[0065] 202. Control a point light source to emit light, and control a two-dimensional liquid crystal unit corresponding to the point light source to generate a plurality of deformations in sequence according to a scanning sequence, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected onto a plurality of sub-fields of view.

[0066] In an optional implementation, the field of view of the radar is divided into a plurality of sub-fields of view, such as Figure 7As shown, the radar's field of view (which can be the entire field of view or a part of the field of view of the area of ​​interest) is divided to obtain a preset number of square sub-fields of view, and the shape of each sub-field of view can be the same or different. In this embodiment, each sub-field of view is a square field of view of the same size as an example. The transmitting module includes a scanning unit, and the scanning unit includes a point light source and a two-dimensional liquid crystal unit corresponding to the point light source. The point light source is controlled to emit light, and the light emitted by the point light source passes through the two-dimensional liquid crystal unit. The sub-field of view that needs to be scanned currently is determined according to the scanning sequence, and the voltage applied to the two-dimensional liquid crystal unit is controlled to deform the two-dimensional liquid crystal unit. The reflected light beam reflected from the two-dimensional liquid crystal unit is projected to the sub-field of view that needs to be scanned currently, and then the two-dimensional liquid crystal unit is controlled to change the phase to scan the next sub-area, and the scanning is performed in sequence according to the scanning sequence until the scanning of all sub-fields of view is completed, that is, the scanning of the field of view area is completed.

[0067] Preferably, the transmitting module also includes a beam shaping unit, which performs homogenization and beam expansion on the reflected light beam reflected by the two-dimensional liquid crystal unit according to the angle of each sub-field of view to obtain a shaped light beam, and reflects the shaped light beam into the sub-field of view so that the shaped light beam can just cover the entire sub-field of view to complete the scanning of the entire sub-field of view. For example, the field of view angle corresponding to the full field of view area is 120°*90°, and the preset number of sub-fields of view is 100. Then, the full field of view area is divided into the preset number of equal parts to obtain the first sub-field of view, and the angle of each first sub-field of view is 12°*9° (e.g. Figure 8 As shown, TX1_zone is the full field of view, which includes multiple square first sub-fields of view). The reflected light beam reflected from the two-dimensional liquid crystal unit is homogenized and expanded according to 12°*9°, and stretched into a square light spot of 12°*9°. The shaped light beam can cover the first sub-field of view of 12°*9°, and complete the scanning of a first sub-field of view. In this way, it is only necessary to change the voltage of the two-dimensional liquid crystal unit 100 times to complete the scanning of 100 first sub-fields of view, and thus the scanning of the full field of view area can be completed.

[0068] Similarly, if the field of view area is the ROI area, for example, the radar field of view angle corresponding to the ROI area is 20°*15°, and the preset number is 100, then the ROI area is divided into the preset number of equal parts to obtain the second sub-field of view, and the angle of each second sub-field of view is 2°*1.5° (such as Figure 8 As shown in the figure, TX2_zone is the ROI range, which includes multiple square second sub-fields of view). The reflected light beam is homogenized and expanded according to 2°*1.5°, and stretched into a square light spot of 2°*1.5°. The shaped light beam can cover the second sub-field of view of 2°*1.5° at one time, and complete the scanning of one second sub-field of view. In this way, only 100 second sub-fields of view need to be scanned to complete the scanning of the ROI area.

[0069] In another optional implementation scheme, since it takes a certain reaction time for the two-dimensional liquid crystal unit to switch from one phase to another, and the radar scanning has high real-time requirements for switching from one sub-field of view to another, if the transmitting module has only one scanning unit, it is necessary to wait for the reaction time to end before scanning another sub-field of view, thereby extending the overall scanning time of the field of view area. Therefore, in order to reduce the overall scanning time and improve the scanning efficiency, the transmitting module includes multiple scanning units, each of which includes a point light source and a two-dimensional liquid crystal unit corresponding to the point light source.

[0070] Preferably, the multiple sub-fields of view are divided into multiple sub-field of view groups according to the scanning sequence; the number of sub-fields of view included in each sub-field of view group is the same as the number of scanning units; and each sub-field of view included in each sub-field of view group corresponds to one scanning unit;

[0071] In the actual application process, Fig. 9 As shown, a total of 4 scanning units are included, each scanning unit includes a point light source two-dimensional liquid crystal unit (the laser 1 in the figure refers to the point light source 1, LCM1 refers to the two-dimensional liquid crystal unit 1, and the rest are the same and will not be repeated here), and the number of sub-fields (ZONE) included in each sub-field group is 4. According to the scanning timing, ZONE1-ZONE4 is the first sub-field group, and ZONE1 corresponds to the first scanning unit, ZONE2 corresponds to the second scanning unit, ZONE3 corresponds to the third scanning unit, and ZONE4 corresponds to the fourth scanning unit. ZONE5-ZONE8 is the second sub-field group, and ZONE5 corresponds to the first scanning unit, ZONE6 corresponds to the second scanning unit, ZONE7 corresponds to the third scanning unit, and ZONE8 corresponds to the fourth scanning unit, and so on.

[0072] Then, the method further includes: for each scanning unit, at every first preset time interval, controlling the two-dimensional liquid crystal unit to deform so that the light emitted by the point light source of the scanning unit switches from a sub-field of view in the previous sub-field of view group to a sub-field of view in the next sub-field of view group.

[0073] In actual application, as an implementation method, during the scanning process of a sub-field of view group, for each scanning unit, the two-dimensional liquid crystal unit is controlled to produce the first deformation, and all the point light sources of all scanning units are controlled to emit light at the same time, then all sub-fields of view in the sub-field of view group ZONE1-ZONE4 are scanned at the same time. When each point light source generates a set number of pulses, the scanning of ZONE1-ZONE4 is completed. The first preset time interval includes at least two parts, the first part is the scanning time of ZONE1-ZONE4, and the second part is the time reserved for the LCM to change the phase after the laser emits the last pulse. That is, within the first preset time interval, the laser completes the scanning of the sub-field of view, and the phase of the LCM has changed, and then the scanning of the second sub-field of view group ZONE5-ZONE8 is performed. And so on, until all sub-field of view groups have completed the scanning, that is, the scanning of the field of view area is completed.

[0074] However, the above scheme has certain defects. The simultaneous luminescence scheme requires that four lasers emit light at the same time, and four LCMs need to be deformed at the same time. Then, after a certain interval, the four LCMs need to change their phases again at the same time to scan the next field of view group. However, in reality, the precision required to control the simultaneous luminescence of the lasers is very high, and the reaction time required for each LCM unit from receiving voltage to completing deformation is not exactly the same. In addition, in this method, ZONE1~ZONE4 are scanned at the same time, and ZONE5~ZONE8 are scanned at the same time, but the two sub-field of view groups need to pause for tens of microseconds of reaction time to change the phase of the LCM, which will cause the scanning process to be discontinuous and uneven.

[0075] Therefore, in another embodiment proposed in the present application, in the case of including 4 scanning units, the ZONEs in each sub-field group are also scanned sequentially, that is, referring to Fig. 9, taking the sub-field of view group ZONE1-ZONE4 as an example, each sub-field of view requires the laser to emit 500 pulses to complete a scan. The time interval between the two pulses emitted by each laser is 5us (this time is used for the laser to recover in order to perform the next pulse emission), and the duration of each pulse is 5ns. The time to scan a ZONE is about 500*5us=2.5ms. After the scanning of ZONE1 is completed, the scanning of ZONE2 is performed. By analogy, the total scanning time of the four sub-fields of view in a sub-field of view group is about 2.5ms*4=10ms. After the scanning of ZONE4 is completed, the laser 1 and LCM1 scan ZONE5, and so on. Therefore, in this solution, the reaction time reserved for each LCM is 2.5ms×3=7.5ms, which is the sum of the scanning time of other sub-fields in a sub-field of view group. This time is much longer than the maximum reaction time of the LCM device from one phase to another (about tens of microseconds). That is, no matter how different the LCM devices are, they can ensure that there is sufficient time for their phase switching. Moreover, in this way, the requirement for simultaneous laser emission is reduced, and the uniformity of scanning of multiple sub-fields of view is improved.

[0076] On the basis of the above embodiments, the present application proposes another embodiment, which uses a point light source cross-time scanning method to complete a pulse scan of all other sub-fields of view in a sub-field of view group, thereby saving the overall scanning time.

[0077] Specifically, the control method also includes:

[0078] For each sub-field of view group, between the pulse intervals of two emission pulses of the point light source of each scanning unit, the point light sources of other scanning units are controlled to emit a pulse, and the light emission time of the point light source of each scanning unit is different.

[0079] Take the sub-viewing field group ZONE1-ZONE4 as an example, refer to Fig. 9 , 10 ( Fig.10 The first to fourth groups in Fig. 9The pulse timing of lasers 1 to 4 in the figure), the point light source of the first scanning unit - laser 1 starts to emit light, emits the first pulse, lasts for 5ns, the pulse interval between the first pulse and the second pulse is 5us, within 5us, lasers 2, 3, and 4 emit a pulse in turn, and the emission time of each laser is different, completing the first scan of ZONE2, ZONE3, and ZONE4, then, laser 1 emits the second pulse, ZONE1 scans the second time, and within the second pulse interval, the second scan of ZONE2, ZONE3, and ZONE4 is completed within 5us..., and so on, until each ZONE has cumulatively emitted a set number (for example, 500) of pulses. Among them, the start time of each scan of lasers 1, 2, 3, and 4 differs by a second preset time interval, and the second preset time interval can be a fixed value or a variable value, such as a difference of 1us between lasers 2 and 3, and a difference of 1.5us between lasers 3 and 4, to ensure that the emission time of the point light source of each scanning unit is different. Thus, ZONE1-ZONE4 are scanned by interleaving pulses in sequence, so that the total time for the four sub-fields to complete the scanning of 500 pulses is about 2.5ms, which is much shorter than the previous 10ms. Subsequently, the above scanning process is copied to the scanning process of ZONE5-ZONE8.

[0080] It should be noted that the above-mentioned pulse interval is related to the recovery time of the laser, that is, the laser needs a certain recovery time from the end of the last light emission to the next light emission. This embodiment takes 5us as an example. In other embodiments, it can be set to other values, which are specifically related to the performance of the laser.

[0081] In the above scheme, switching from one sub-field of view to another is mainly achieved by changing the control voltage of LCM. The more sub-fields of view there are, the more frequently LCM needs to change its phase; the larger the pulse interval, the more time left for LCM to recover, but this will also affect the overall scanning efficiency. Therefore, it is necessary to determine the scanning parameters of the system based on the characteristics of the LCM device through simulation or experiment.

[0082] However, in the above method, although the scanning time of each sub-field group is reduced, the phase change time reserved for each two-dimensional liquid crystal unit will be shortened. Therefore, each scanning unit needs to pause briefly when switching from one sub-field group to another. That is to say, taking laser 1+LCM1 as an example, after 2.5ms, ZONE1 is scanned, and then ZONE5 should be scanned. LCM1 needs to change phase, which takes tens of microseconds, that is, it needs to pause for more than tens of microseconds between the end time of the last pulse of ZONE1 and the start time of the first pulse of ZONE5, and the scanning process is slightly discontinuous.

[0083] In another embodiment of the present application, an optimization method is provided for the above problem. Specifically, the method further includes:

[0084] The two-dimensional liquid crystal unit corresponding to each point light source is controlled to generate the first phase to scan the current sub-field group. The scanning process is divided into three stages:

[0085] The first stage: controlling the point light sources of all scanning units to emit a first number of pulses in sequence;

[0086] The second stage: controlling the point light sources of all scanning units to emit a second number of pulses alternately;

[0087] The third stage: controlling the point light sources of all scanning units to emit a third number of pulses in sequence;

[0088] After the current sub-viewing field group is scanned, the two-dimensional liquid crystal unit corresponding to each point light source is controlled to generate a second phase, so that the scanning process switches from the current sub-viewing field group to the next sub-viewing field group;

[0089] by Fig.11 For example, before the laser emits a pulse, the four LCMs are first controlled to produce a first phase change (the first phase of each LCM can be different), and then during the scanning process of ZONE1-ZONE4,

[0090] Phase 1: Lasers 1 to 4 emit the first number of pulses in sequence, assuming 50 pulses. After the previous laser has finished emitting 50 pulses, the next laser starts emitting 50 pulses, and so on. The pulses emitted by lasers 1 to 4 are respectively reflected to ZONE1-ZONE4 by LCM1 to LCM4 in the first phase. Assuming that each pulse lasts 5ns and the pulse interval is 5us, the first phase takes a total of about 5us×50×4=1ms (nanoseconds are negligible relative to microseconds).

[0091] The second stage: Lasers 1 to 4 emit a second number of pulses alternately, assuming 400 pulses, wherein the pulses of the remaining lasers are emitted during the pulse interval of each laser, and so on.... The pulses emitted by lasers 1 to 4 are respectively reflected to ZONE1-ZONE4 through LCM1 to LCM4. Assuming that each pulse lasts 5ns and the pulse interval is 5us, the second stage takes a total of about 5us×400=2ms.

[0092] The third stage: Lasers 1 to 4 emit a third number of pulses in sequence, assuming 50 pulses. After the previous laser has finished emitting 50 pulses, the next laser starts emitting 50 pulses, and so on. And so on... The pulses emitted by lasers 1 to 4 are respectively reflected to ZONE1-ZONE4 through LCM1 to LCM4. Assuming that each pulse lasts 5ns and the pulse interval is 5us, the third stage takes a total of about 5us×50×4=1ms.

[0093] When the third stage is completed, LCM receives the control instruction to change the phase from the first phase to the second phase, and scans the second sub-field of view group (ZONE5-ZONE8). In this way, the phase change time left for LCM1 is the sum of the pulse emission times of lasers 2, 3, and 4 in the third stage of the previous sub-field of view group (ZONE1-ZONE4), that is, 5us×50×3=0.75ms; the phase change time left for LCM2 is the sum of the emission times of 50 pulses of lasers 3 and 4 in the third stage of the previous sub-field of view group (ZONE1-ZONE4) and laser 1 in the first stage of the current sub-field of view group (ZONE5-ZONE8), which is also 5us×50×3=0.75ms; the phase change time left for LCM3 is The sum of the emission times of the 50 pulses of the laser 4 in the third stage of the previous sub-field of view group (ZONE1-ZONE4) and the lasers 1 and 2 in the first stage of the current sub-field of view group (ZONE5-ZONE8) is also 5us×50×3=0.75ms; the phase change time left for LCM4 is the sum of the emission times of the 50 pulses of the lasers 1, 2, and 3 in the first stage of the current sub-field of view group (ZONE5-ZONE8), which is also 5us×50×3=0.75ms; and the time of 0.75ms can already meet the phase change time of most LCM intervals. It can be seen that by splitting the pulse timing of multiple scanning units in the scanning process of a sub-field of view group into different stages, the process of switching from one sub-field of view group to the next sub-field of view group has reserved the same and sufficient phase change time for each LCM device. Based on this, although the scanning time of each sub-field of view group is slightly increased, the scanning switching process is continuous and does not require pauses.

[0094] The values ​​of the first number, the second number, the third number, the pulse interval, the sub-field of view size and the like are exemplary and can be adjusted according to different characteristics of the LCM device.

[0095] Preferably, the transmitting module includes a first scanning unit and a second scanning unit, which divide the full field of view area into multiple first sub-fields of view; and divide the ROI area into multiple second sub-fields of view; wherein the ROI area is a part of the full field of view area; with respect to the full field of view area, the point light source of the first scanning unit is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to a scanning sequence, so that the point light source emits light through the two-dimensional liquid crystal unit and is projected onto multiple first sub-fields of view; with respect to the ROI area, the point light source of the second scanning unit is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to a scanning sequence, so that the point light source emits light through the two-dimensional liquid crystal unit and is projected onto multiple second sub-fields of view; and point cloud data fusion of the ROI area is performed according to the scanning results of the first sub-field of view and the second sub-field of view.

[0096] It should be noted that, in order to improve the detection capability of the ROI area, the transmitting module is set to include a first scanning unit and a second scanning unit, and the ROI area is a part of the full field of view area. At this time, when the first scanning unit scans the first sub-field of view, it will also put energy into the second sub-field of view, so the scanning energy of the ROI area is the superposition of the first scanning unit and the second scanning unit. Specifically, according to the scanning results of the first sub-field of view and the second sub-field of view, the point cloud data of the ROI area is fused.

[0097] As an implementation method, Figure 8 As shown, TX1_zone is the full field scanning range corresponding to the first scanning unit. It can be seen that the full field is divided into multiple square sub-fields of view. TX2_zone is the scanning range of the ROI area corresponding to the second scanning unit. The ROI area is also divided into multiple sub-fields of view. In TX2_zone, the sum of the scanning energy is the sum of the energy of the first scanning unit and the second scanning unit. When data fusion is performed, the scanning result of the first scanning unit on TX2_zone and the scanning result of the second scanning unit on TX2_zone need to be added to obtain the scanning result of the ROI area.

[0098] exist Figure 8 In the example, the size of the sub-field of view in the ROI area is inconsistent with that of the sub-field of view in the full field of view area, and the size of the sub-field of view in the ROI area is smaller than that of the sub-field of view in the TX1_zone. This arrangement allows the sub-field of view in the ROI area to be divided more finely, the beam energy to be more concentrated, and the scanning effect to be better. However, in this way, the first scanning unit and the second scanning unit require completely different shaping and homogenizing devices, and the timing control of the first scanning unit and the second scanning unit is also relatively independent, which increases the complexity of the control.

[0099] The present application further proposes an embodiment, based on the above embodiment, the sub-field of view size of the ROI area and the sub-field of view size of the full field of view area are set to be the same, specifically, including:

[0100] Select several sub-fields of view from the first sub-field of view as the second sub-field of view. Since the second sub-field of view comes from the first sub-field of view, the size of the first sub-field of view is the same as that of the second sub-field of view. Therefore, point cloud data of the same size is obtained. In the subsequent point cloud fusion, the fusion can be directly performed in units of sub-fields of view, avoiding the problem of inconsistent sizes, and making it possible for the uniform light devices of the first scanning unit and the second scanning unit to be partially reused, reducing the system volume. The scanning frequency and the timing of the receiving and transmitting pulses of the first scanning unit and the second scanning unit can also adopt a unified standard, reducing the complexity of control.

[0101] Then, the point cloud data of the ROI area is fused according to the scanning results of the first sub-field of view and the second sub-field of view, including: for each second sub-field of view, fusing the scanning data of the second sub-field of view scanned by the first scanning unit and the scanning data of the second sub-field of view scanned by the second scanning unit to obtain sub-area fused point cloud data; and splicing the sub-area fused point cloud data of all the second sub-fields of view to obtain the fused point cloud data of the ROI area.

[0102] Preferably, Fig.12 As shown, since the receiving lens has a large field of view, the scanning spot and the detector target surface cannot be well aligned, and there is a distortion phenomenon, that is, the imaging spot has a position offset. Usually, the offset is small at the center of the image and large at the edge of the image, which will greatly reduce the ranging performance of the edge angle. Therefore, in this application, when detecting the edge of the field of view, the receiving module does not receive according to the position corresponding to the square and regular sub-field of view, but will make some adjustments based on the position corresponding to the sub-field of view according to the distortion amount, such as Fig.12 As shown, the distorted position corresponding to each sub-field of view is pre-calibrated within the field of view. When controlling the LCM, the distortion factor is taken into consideration and the corresponding light is reflected to the distorted sub-field of view position to offset the influence of the distortion.

[0103] The control method of the laser radar provided in the embodiment of the present application first divides the field of view area to obtain multiple sub-fields of view; then controls the point light source to emit light, and controls the two-dimensional liquid crystal unit corresponding to the point light source to generate multiple deformations in sequence according to the scanning sequence, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple sub-fields of view. By controlling the scanning of a sub-field of view to be covered by one deformation, the field of view area will not be scanned repeatedly. After scanning all sub-fields of view, the scanning of the field of view area is completed, thereby improving the scanning efficiency.

[0104] Further, as Figure 3In a specific implementation of the method, the present application provides a control device for a laser radar architecture, such as Figure 4 As shown, the device includes: a division module 301 and a control module 302.

[0105] A division module 301 is used to divide the field of view area into multiple sub-fields of view;

[0106] The control module 302 is used to control the point light source to emit light, and control the two-dimensional liquid crystal unit corresponding to the point light source to generate multiple deformations in sequence according to the scanning sequence, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple sub-fields of view in sequence.

[0107] In a specific application scenario, the multiple sub-fields of view are divided into multiple sub-field of view groups according to a scanning sequence; the number of sub-fields of view included in each sub-field of view group is the same as the number of scanning units; and each sub-field of view included in each sub-field of view group corresponds to a scanning unit; the control device also includes: a switching module 303, which is used to control the deformation of the two-dimensional liquid crystal unit for each scanning unit at a first preset time interval, so that the light emitted by the point light source of the scanning unit switches from a sub-field of view in the previous sub-field of view group to a sub-field of view in the next sub-field of view group; the first preset time interval is greater than the response time of the two-dimensional liquid crystal unit.

[0108] In a specific application scenario, the control device further includes: a scanning module 304, which is used to, during a scanning process of each sub-field of view group, make the light emission start time of the point light sources corresponding to each sub-field of view in the sub-field of view group differ by a second preset time interval.

[0109] In a specific application scenario, the transmitting module includes a first scanning unit and a second scanning unit, and the control device also includes: a first fusion module 305, which is used to divide the full field of view area to obtain multiple first sub-fields of view; divide the ROI area to obtain multiple second sub-fields of view; wherein the ROI area is a part of the full field of view area; for the full field of view area, the point light source of the first scanning unit is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to the scanning sequence, so that the point light source emits light through the two-dimensional liquid crystal unit and is projected to the multiple first sub-fields of view; for the ROI area, the point light source of the second scanning unit is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to the scanning sequence, so that the point light source emits light through the two-dimensional liquid crystal unit and is projected to the multiple second sub-fields of view; according to the scanning results of the first sub-field of view and the second sub-field of view, the point cloud data of the ROI area is fused.

[0110] In a specific application scenario, the control device also includes: a second fusion module 306, which is used to select several sub-fields of view from the first sub-field of view as the second sub-field of view; then, the point cloud data of the ROI area is fused according to the scanning results of the first sub-field of view and the second sub-field of view, including: for each second sub-field of view, the scanning data of the second sub-field of view obtained by scanning the first scanning unit and the scanning data of the second sub-field of view obtained by scanning the second scanning unit are fused to obtain sub-area fused point cloud data; the sub-area fused point cloud data of all the second sub-fields of view are spliced ​​to obtain the fused point cloud data of the ROI area.

[0111] The control device of the laser radar architecture provided in the embodiment of the present application can control the phase deflection of the liquid crystal in two dimensions by changing the voltage applied to the two dimensions of the two-dimensional liquid crystal unit. Therefore, the range and position of the light beam reflected from the two-dimensional liquid crystal unit can be flexibly adjusted, thereby flexibly adjusting the scanned field of view range and position.

[0112] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0114] In an exemplary embodiment, see Fig.13 , and also provides a computer device, which includes a bus, a processor, a memory and a communication interface, and may also include an input and output interface and a display device, wherein each functional unit can communicate with each other through the bus. The memory stores a computer program, and the processor is used to execute the program stored in the memory and execute the control method of the laser radar in the above embodiment.

[0115] In an exemplary embodiment, the present application also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the control method of the solid-state laser radar are implemented.

[0116] Through the description of the above implementation methods, those skilled in the art can clearly understand that the present application can be implemented by hardware, or by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each implementation scenario of the present application.

[0117] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of a preferred implementation scenario, and the modules or processes in the accompanying drawings are not necessarily required for implementing the present application.

[0118] Those skilled in the art will appreciate that the modules in the device in the implementation scenario can be distributed in the device in the implementation scenario according to the implementation scenario description, or can be changed accordingly and located in one or more devices different from the implementation scenario. The modules in the above implementation scenario can be combined into one module, or can be further split into multiple sub-modules.

[0119] The above application serial numbers are for description only and do not represent the advantages or disadvantages of the implementation scenarios.

[0120] The above disclosure only discloses several specific implementation scenarios of the present application. However, the present application is not limited thereto, and any changes that can be conceived by technicians in this field should fall within the scope of protection of the present application.

Claims

1. A laser radar architecture, comprising a transmitting module and a receiving module, characterized in that: The transmitting module includes a scanning unit, which includes a point light source and a two-dimensional liquid crystal unit corresponding to the point light source; the light emitted by the point light source is reflected into the environment through the corresponding two-dimensional liquid crystal unit, so as to scan the environment; The receiving module is used to receive reflected light returned from the environment to form a scanning result of the field of view area.

2. The laser radar architecture according to claim 1, characterized in that: The transmitting module includes a beam shaping unit; The beam shaping unit is used to homogenize and expand the reflected light beam reflected by the two-dimensional liquid crystal unit to obtain a shaped light beam, and reflect the shaped light beam into the environment.

3. A laser radar control method, characterized in that: The control method is applied to the laser radar architecture according to any one of claims 1 to 2, and the control method comprises: Dividing the field of view area to obtain multiple sub-fields of view; The point light source is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to a scanning sequence, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple sub-fields of view in sequence.

4. The control method of the laser radar according to claim 3, characterized in that: The multiple sub-fields of view are divided into multiple sub-field of view groups according to the scanning sequence; the number of sub-fields of view included in each sub-field of view group is the same as the number of scanning units; and each sub-field of view included in each sub-field of view group corresponds to one scanning unit; Then, the method further comprises: For each scanning unit, at every first preset time interval, the two-dimensional liquid crystal unit is controlled to deform so that the light emitted by the point light source of the scanning unit switches from a sub-field of view in a previous sub-field of view group to a sub-field of view in a next sub-field of view group; The first preset time interval is greater than a response time of the two-dimensional liquid crystal unit.

5. The control method of the laser radar according to claim 4, characterized in that: The method further comprises: For each sub-field of view group, between the pulse intervals of two emission pulses of the point light source of each scanning unit, the point light sources of other scanning units are controlled to emit a pulse, and the light emission time of the point light source of each scanning unit is different.

6. The control method of the laser radar according to claim 4, characterized in that: The method further comprises: The two-dimensional liquid crystal unit corresponding to each point light source is controlled to generate the first phase to scan the current sub-field group. The scanning process is divided into three stages: The first stage: controlling the point light sources of all scanning units to emit a first number of pulses in sequence; The second stage: controlling the point light sources of all scanning units to emit a second number of pulses alternately; The third stage: controlling the point light sources of all scanning units to emit a third number of pulses in sequence; After the current sub-viewing field group is scanned, the two-dimensional liquid crystal unit corresponding to each point light source is controlled to generate a second phase, so that the scanning process switches from the current sub-viewing field group to the next sub-viewing field group.

7. The control method of the laser radar according to any one of claims 3 to 6, characterized in that: The transmitting module includes a first scanning unit and a second scanning unit, and the method further includes: The full field of view area is divided to obtain a plurality of first sub-fields of view; the ROI area is divided to obtain a plurality of second sub-fields of view; wherein the ROI area is a part of the full field of view area; For the full field of view, the point light source of the first scanning unit is controlled to emit light, and the two-dimensional liquid crystal unit corresponding to the point light source is controlled to generate multiple deformations in sequence according to the scanning timing, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple first sub-fields of view; For the ROI area, control the point light source of the second scanning unit to emit light, and control the two-dimensional liquid crystal unit corresponding to the point light source to generate multiple deformations in sequence according to the scanning timing, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple second sub-fields of view; According to the scanning results of the first sub-field of view and the second sub-field of view, point cloud data fusion of the ROI area is performed.

8. The control method of the laser radar according to claim 7, characterized in that: The method further comprises: Selecting a plurality of sub-fields of view from the first sub-field of view as the second sub-field of view; Then, the step of fusing the point cloud data of the ROI area according to the scanning results of the first sub-field of view and the second sub-field of view includes: For each second sub-field of view, fusing the scan data of the second sub-field of view scanned by the first scanning unit with the scan data of the second sub-field of view scanned by the second scanning unit to obtain sub-region fused point cloud data; The fused point cloud data of all sub-regions of the second sub-field of view are spliced ​​to obtain the fused point cloud data of the ROI region.

9. A laser radar control device, characterized in that: The control device comprises: A division module, used for dividing the field of view area to obtain multiple sub-fields of view; The control module is used to control the light emission of the point light source and control the two-dimensional liquid crystal unit corresponding to the point light source to generate multiple deformations in sequence according to the scanning sequence, so that the light emitted by the point light source passes through the two-dimensional liquid crystal unit and is projected to multiple sub-fields of view in sequence.

10. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the control method of the laser radar described in any one of claims 3 to 8 are implemented.

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