Multi-channel laser emission control method, device and computer-readable storage medium

Abstract

This application relates to a method, device, and computer-readable storage medium for controlling multi-channel laser emission. The method includes: controlling the emission of secondary lasers from multiple channels of a multi-channel laser radar during its operating cycle; and emitting a primary laser or code-modulating the emission of the primary laser at a preset reference time for each channel based on the detection results of the secondary lasers from the multiple channels. The solution provided by this application can prevent channel crosstalk during multi-channel laser detection without increasing firmware costs.

Description

Technical Field

[0001] The present application relates to the field of laser radar, and in particular to a control method, device and computer-readable storage medium for multi-channel laser emission. Background Art

[0002] LiDAR consists of a transmitting system, a receiving system, a scanning control system, and a data processing system. It measures distance by measuring the time difference between the emitted detection laser and the received echo laser. It has the advantages of high resolution, high sensitivity, strong anti-interference ability, and is not affected by lighting conditions. It has been widely used in autonomous driving, logistics vehicles, robots, vehicle-road collaboration, and public smart transportation.

[0003] Multi-channel LiDARs enable simultaneous scanning of multiple channels, expanding the field of view, and are currently widely used in LiDAR products. Because LiDAR transmits and receives data simultaneously across multiple channels, crosstalk can occur between channels. This crosstalk can cause artifacts and lead to detection errors. Related technologies address this crosstalk during multi-line laser transmission through physical optical isolation. However, physical optical isolation solutions require additional hardware or structural changes to LiDAR products, which translates to increased costs. Summary of the Invention

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a control method, device and computer-readable storage medium for multi-channel laser emission, which prevent channel crosstalk during multi-channel laser detection without increasing firmware costs.

[0005] A first aspect of the present application provides a method for controlling multi-channel laser emission, comprising:

[0006] During the working cycle of the multi-channel laser radar, time-sharing control is performed on the emission of secondary lasers of multiple channels of the multi-channel laser radar;

[0007] According to the detection results of the secondary lasers of the multiple channels, the main laser is emitted at a preset reference time of the channel or the emission of the main laser is coded and modulated.

[0008] A second aspect of the present application provides a control device for multi-channel laser emission, comprising:

[0009] A first control module is used to control the emission of secondary lasers of multiple channels of the multi-channel laser radar in a time-sharing manner during a working cycle of the multi-channel laser radar;

[0010] The second control module is configured to emit a main laser or code-modulate the emission of the main laser at a preset reference time of the channel according to the detection results of the secondary lasers of the multiple channels.

[0011] A third aspect of the present application provides an electronic device, including:

[0012] processor; and

[0013] The memory stores executable codes thereon, and when the executable codes are executed by the processor, the processor is caused to execute the method described above.

[0014] A fourth aspect of the present application provides a computer-readable storage medium having executable code stored thereon. When the executable code is executed by a processor of an electronic device, the processor is caused to execute the method described above.

[0015] It can be seen from the technical solution provided by the present application that, during the working cycle of a multi-channel laser radar, the emission of secondary lasers of multiple channels of the multi-channel laser radar is controlled by time-sharing, and the emission of the main laser or the encoding and modulation of the main laser is emitted at a reference time preset by the channel according to the detection results of the secondary lasers of multiple channels. The detection cycle of each channel of the laser radar includes a secondary cycle and a main cycle. The laser radar of multiple channels includes multiple secondary cycles and a main cycle, and the duration of the working cycle of the laser radar is limited by the system frame rate. The emission of secondary lasers of multiple channels is controlled by time-sharing, and the emission of the main laser or the encoding and modulation of the main laser is emitted at a reference time preset by the channel, so that the secondary cycles and the main cycle of multiple channels can be separated in time, or the reflected laser of the channel can be identified by encoding and decoding, thereby preventing channel crosstalk during the operation of the multi-channel laser without increasing the cost.

[0016] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present application will become more apparent by describing in more detail exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0018] Figure 1a This is a schematic diagram of the structure of a multi-channel laser radar provided in an embodiment of the present application;

[0019] Figure 1b 1 is a schematic diagram of the splicing of the field of view formed by the channels of a five-channel laser radar provided in an embodiment of the present application;

[0020] Figure 2 1 is a flow chart of a method for controlling multi-channel laser emission provided in an embodiment of the present application;

[0021] Figure 3aThis is a schematic diagram of the main laser emission timing when all five channels of the laser radar provided in an embodiment of the present application adopt the close-range working mode;

[0022] Figure 3b This is a schematic diagram of the main laser emission timing when the five channels of the laser radar provided in an embodiment of the present application partially adopt the close-range working mode and partially adopt the long-range working mode;

[0023] Figure 4 Schematic diagram of the structure of a multi-channel laser emission control device provided in an embodiment of the present application;

[0024] Figure 5 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] The following describes embodiments of the present application in more detail with reference to the accompanying drawings. Although the accompanying drawings illustrate embodiments of the present application, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0026] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0027] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] Multi-channel LiDAR can scan multiple channels simultaneously and expand the field of view of LiDAR. It is currently widely used in LiDAR products. For example, a multi-channel LiDAR that uses MEMS (Micro-Electro-Mechanical System) for scanning can be used. Figure 1aAs shown, the multi-channel laser radar includes a transceiver module and a scanning module. The scanning module uses a MEMS galvanometer. The transmitter of the transceiver module emits an outgoing laser (as shown by the straight solid line with an arrow in the figure) to the scanning module, and the MEMS galvanometer of the scanning module moves to scan and cover the entire field of view. The outgoing laser is reflected by the object and returns as a reflected laser (as shown by the straight dotted line with an arrow in the figure), and the optical paths of the reflected laser and the outgoing laser are coaxial. The reflected laser returns along the original path from the scanning module to the transceiver module and is received by the receiver in the transceiver module. Due to the limited deflection angle of the MEMS galvanometer, the field of view covered by the optical path of a transceiver module after passing through the scanning module is small. In order to expand the field of view of the laser radar, multiple transceiver modules are set up, and a MEMS galvanometer is shared for scanning to form the effect of stitching multiple fields of view, as shown in the figure. Figure 1b The figure below shows a spliced diagram of the field of view formed by the channels of a five-channel LiDAR. Each transceiver module represents a channel of the LiDAR, and the light (outgoing and reflected lasers) between the multiple channels is isolated from each other.

[0029] On the one hand, the system frame rate determines that the detection cycle is limited in length, and the length of the analysis area of each channel (including the primary analysis area and the secondary analysis area) is also related to the system's ranging capability, so its length is fixed. Therefore, if the analysis areas of different channels overlap in time, it will cause crosstalk between the optical paths of each channel, that is, each channel may receive reflected lasers that are not corresponding to the channel; on the other hand, when a multi-channel lidar emits an outgoing laser, it adopts a charging, conversion and enabling driving scheme. Since charging and conversion take a certain amount of time, the difficulty of timing control increases. Without a better timing control scheme, crosstalk will also occur between the channels. The relevant technology is to solve the crosstalk of multiple channels through physical optical isolation. However, the solution of physical optical isolation requires adding hardware or changing the structure of the lidar product, which means rising costs.

[0030] In response to the above problems, an embodiment of the present application provides a control method for multi-channel laser emission, which can prevent channel crosstalk during multi-channel laser detection without increasing firmware costs.

[0031] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0032] See also Figure 2 , is a flow chart of a method for controlling multi-channel laser emission according to an embodiment of the present application, which mainly includes steps S201 to S202, as described below:

[0033] Step S201: During the working cycle of the multi-channel laser radar, the emission of secondary lasers of multiple channels of the multi-channel laser radar is controlled in a time-sharing manner.

[0034] Since a multi-channel laser radar completes a detection task by scanning multiple channels, the process of multiple channels completing a detection task can be defined as a working cycle of the multi-channel laser radar. For example, assuming that the multi-channel laser radar has five channels, CH1 to CH5, the period from the start of the five channels CH1 to CH5 at the same preset moment (for example, the preset moment can be the moment when the galvanometer start signal is generated or the moment generated by the internal clock of the multi-channel laser radar) to the completion of a detection task can be called a working cycle of the multi-channel laser radar.

[0035] For each channel of a multi-channel lidar, the detection cycle consists of a secondary and primary cycle. During the secondary cycle, a secondary laser is emitted and the corresponding reflected laser is received. Similarly, during the primary cycle, a primary laser is emitted and the corresponding reflected laser is received. The detection results from the secondary and primary cycles are combined to produce a single detection result covering the entire ranging range. Ranging begins when the laser emits the outgoing laser. The receiver is then turned on and in operation until the analysis zone has elapsed, at which point it is turned off. The analysis zone is equal to or greater than the round-trip flight time of the outgoing laser photons to the maximum detection range to ensure that the return photons from the maximum detection range can be received. The greater the outgoing laser power, the greater the maximum detection range, and the corresponding longer the analysis zone. As previously mentioned, the lower the secondary laser power, the shorter the secondary analysis zone. The secondary laser power is the same for each channel, and the duration of the secondary analysis zone for each channel is a second preset time.

[0036] As an embodiment of the present application, time-sharing control of the emission of secondary lasers of multiple channels of a multi-channel laser radar can be achieved by sequentially controlling the emission of secondary lasers of multiple channels at intervals of a first preset time. Taking the aforementioned multi-channel laser radar with 5 channels from CH1 to CH5 as an example, the secondary laser of CH1 is emitted at time T1, the secondary laser of CH2 is emitted at time T2, and so on, the secondary laser of CH5 is emitted at time T5. The emission time intervals of the secondary lasers of adjacent channels are the first preset time, that is, the interval between T1 and T2 is the first preset time, the interval between T2 and T3 is the first preset time, the interval between T3 and T4 is the first preset time, and the interval between T4 and T5 is the first preset time.

[0037] The first preset time is greater than or equal to the second preset time. If the second preset time is greater than the first preset time, the secondary analysis areas of different channels overlap in time. While the receiver of the previous channel (e.g., CH1) is still in operation, the secondary laser of the next channel (e.g., CH2) has begun emitting. At this time, the reflected laser received by the CH1 receiver may be the reflected laser corresponding to the secondary laser of CH1 or the reflected laser corresponding to the secondary laser of CH2. However, the CH1 receiver cannot distinguish which channel's outgoing laser the received reflected laser corresponds to, resulting in channel crosstalk between CH1 and CH2. Therefore, the first preset time must be greater than or equal to the second preset time. Otherwise, it will create conditions for crosstalk between channels and increase the probability of crosstalk between channels.

[0038] The secondary lasers of multiple channels are emitted sequentially, and the secondary detection cycle takes up a total of five times the first preset time. As can be seen from the foregoing, the operating cycle of a multi-channel lidar is limited, and the first preset time can be set to a minimum equal to the second preset time. The second preset time, i.e., the length of the secondary analysis zone, is related to the output power of the secondary lasers. Therefore, if the system parameters of the multi-channel lidar are already determined, the second preset time is a known and fixed quantity.

[0039] Since the secondary analysis area is short, the time of the five secondary detection cycles does not take up much of the working cycle of the multi-channel lidar. Therefore, time-sharing control can be used to control the emission of secondary lasers of multiple channels to avoid crosstalk between multiple channels during the secondary detection cycle.

[0040] In the laser radar optical path, a small portion of the energy of the outgoing laser light directly reaches the receiver through stray paths (i.e., stray light). The echo laser received by the receiver includes both stray light and reflected laser light from the outgoing laser light. Receiving this stray light excites a certain number of single-photon units, which output a photocurrent signal, known as the leading signal. Actual reflected laser light from a nearby target object reaches the receiver faster, and its photocurrent signal (reflection signal) is superimposed on the leading signal, making it impossible to identify and resulting in detection failure. In practice, the higher the outgoing light power, the greater the stray light energy, and the longer the leading signal quenching time. Stray light directly causes the receiver to saturate prematurely, making it unable to respond to reflected laser light for close-range detection, thereby creating a near-field blind spot in the laser radar. The different transmit powers of the primary and secondary lasers correspond to different ranging ranges and near-field blind spots. Within the same detection cycle, the detection results of the primary and secondary lasers are combined to generate point cloud data covering the entire ranging range. For example, the secondary detection cycle detects the near-field area of 0 to 20m to obtain the secondary detection result; if the main laser adopts the long-distance working mode at this time, the main detection cycle detects the far-field area of 15 to 200m to obtain the main detection result; after splicing and fusing the two sets of detection results, point cloud data covering 0 to 200m is obtained, thereby eliminating the near-field blind spot of laser detection.

[0041] Specifically, controlling the secondary laser intervals of multiple channels to emit at a first preset time may be: at a first moment, controlling each channel in the multiple channels to start secondary charging; starting the secondary energy conversion of each channel at the end of the secondary charging; after the secondary energy conversion of each channel is completed, controlling each channel in turn to start secondary enabling, the channel emits secondary lasers, and the secondary enabling moments of adjacent channels are separated by the first preset time.

[0042] It should be noted that the laser radar can be driven by a constant voltage source. The advantage of this driving scheme is that it directly drives the emission of the laser and can quickly respond and adjust the power of the emitted light. The disadvantage is that the constant voltage source requires a high power, resulting in high cost and power consumption. When the laser radar uses a constant voltage source to directly drive the laser, the above-mentioned control of the secondary laser emission of multiple channels is performed at a first preset time interval. It can be: at the time of the secondary laser emission of each channel, a control instruction is sent to the driving circuit. After receiving the control instruction, the driving circuit turns on the constant voltage source to cause the laser to emit. Specifically, at time T1, a driving instruction is sent to the driving circuit of CH1 to turn on the constant voltage source, and the laser emits a secondary laser. After the first preset time, at time T2, a driving instruction is sent to the driving circuit of CH1 to turn on the constant voltage source, and the laser emits a secondary laser. And so on, until the laser of CH5 emits a secondary laser at time T5. The driving circuits of multiple channels can be shared, or each channel can be provided with a corresponding driving circuit.

[0043] Another driving scheme for LiDAR is to use charging, energy conversion, and enabling. The charging phase involves charging an energy storage element with a power supply and storing the electrical energy in the energy storage element. The energy conversion phase involves transferring the electrical energy stored in the energy storage element to the energy conversion element after the charging phase is completed. The enabling phase involves releasing the electrical energy stored in the energy conversion element to drive the laser to emit laser light after the energy transfer is completed. Since charging and energy conversion both take a certain amount of time, in order to ensure the frame rate of the laser point cloud data, the charging, energy conversion, and enabling of the driving circuit have strict timing requirements, which are explained as follows:

[0044] (1) Charging and energy transfer are continuous in timing, that is, after charging is completed, energy transfer begins immediately. Specifically, the driving circuit starts to charge when it receives the charging start instruction, and then ends charging when it receives the charging end instruction, and energy transfer begins at the same time;

[0045] (2) After the transfer is completed, the enabling can begin, specifically, the enabling signal is received and the enabling begins;

[0046] (3) When enabling, all the electrical energy stored in the energy conversion element is released at once. One energy conversion must correspond to one enabling;

[0047] (4) The power supply can also be enabled during the charging process of the energy storage element.

[0048] The first moment can be the moment after the maximum coding enable of the main laser in the previous operating cycle ends. The detection cycle includes a secondary detection cycle and a primary detection cycle. When the main laser operates in long-distance mode, coded modulation is used, meaning a random time is added before the main laser begins charging. The maximum coding is the maximum length of this reserved random time. Setting the first moment after the maximum coding enable of the main laser in the previous operating cycle ends ensures that the secondary charging and secondary transfer of all channels in the current cycle begin after all channels have completed their previous operating cycle. The secondary charging and transfer times for all channels are the same, simplifying the control logic. Specifically, the first moment can be the moment after a preset time has passed since the maximum coding enable of the main laser in the previous operating cycle ended. This preset time can be set according to actual needs, for example, from 6ns to 13ns. The longer the charging time, the more electrical energy is stored in the energy storage element, and the higher the power of the emitted light. The emission power of the secondary laser is determined, as is the charging time of the secondary laser. The energy conversion field of view should exceed the preset lower limit time to ensure that the electrical energy stored in the energy storage element can be transferred to the energy conversion element. For multi-channel lidar, the system frame rate determines the limited detection cycle time, and the length of the analysis area of each channel (including the main analysis area and the secondary analysis area) is also related to the system's ranging capability, so its duration is fixed. Therefore, if the secondary analysis areas of different channels overlap in time, it will cause crosstalk between the optical paths of each channel, that is, each channel may receive a reflected laser that does not correspond to the channel. Therefore, during the working cycle of the multi-channel lidar, the emission of the secondary lasers of multiple channels of the multi-channel lidar can be controlled in time-sharing, so that the secondary lasers of multiple channels are emitted in sequence to avoid crosstalk.

[0049] Step S202: Based on the detection results of the secondary lasers of the multiple channels, the main laser is emitted or the emission of the main laser is coded and modulated at a reference time preset for the channel.

[0050] As can be seen above, each channel's detection cycle consists of secondary and primary detection. The primary laser's operating mode is determined based on the secondary laser's detection results. The primary laser operates in two modes: short-range and long-range. These two modes have different transmit powers and corresponding analysis zone lengths. Therefore, different emission timings are used to ensure that multiple channels complete a detection cycle within the lidar's operating cycle.

[0051] As an embodiment of the present application, based on the detection results of the secondary lasers of multiple channels, the emission of the main laser or the code-modulation of the emission of the main laser at a reference time preset by the channel can be: based on the detection results of multiple secondary lasers, the working mode of the main laser of the corresponding channel is judged to obtain the working mode of the main laser of all channels; if the main laser of the channel adopts the short-range working mode, the main laser is emitted at the reference time preset by the channel; if the main laser of the channel adopts the long-range working mode, the emission of the main laser is code-modulated.

[0052] Regarding the above-mentioned determination of the operating mode of the main laser of the corresponding channel based on the detection results of multiple secondary lasers, and obtaining the operating modes of the main lasers of all channels, it should be noted that:

[0053] First, the detection results of a channel's secondary laser only determine the operating mode of the corresponding channel's primary laser. Within the same operating cycle, the primary lasers of different channels can operate in different modes. For example, during the current operating cycle, the primary lasers of channels CH1, CH2, and CH5 operate in long-range mode, while the primary lasers of channels CH3 and CH4 operate in close-range mode.

[0054] There are three possible working modes of the main lasers of all channels obtained by the lidar: 1) The main lasers of all channels adopt the long-distance working mode, and the emission of the main lasers of all channels is coded and modulated; 2) The main lasers of all channels adopt the short-distance working mode, and all channels emit the main lasers at their preset reference times; 3) The main lasers of some channels adopt the long-distance working mode, and the emission of the main lasers of these channels is coded and modulated, and the main lasers of the remaining channels adopt the short-distance working mode, and the remaining channels emit the main lasers at the preset reference times.

[0055] Second, when the lidar laser's drive circuit uses a high-voltage constant-voltage source, it can quickly respond and adjust the laser's output power. In this case, the operating mode of the primary laser for the corresponding channel in the current detection cycle can be determined based on the detection results of the secondary laser in the current detection cycle. Based on the detection results of the secondary laser in the current detection cycle, the operating mode of the primary laser is determined, and the corresponding drive instructions are sent to the drive circuit. The drive circuit can then quickly respond and activate the constant-voltage source to directly drive the laser to emit the primary laser at the corresponding power.

[0056] However, to control input power, lidars typically use a charging, transfer, and enable drive circuit to drive the laser. When driving the laser, the power supply first charges the charging module, storing energy in the inductor. Once charging is complete, the energy stored in the inductor is transferred to the storage capacitor according to the transfer command. Finally, according to the transmitted enable command, the energy stored in the storage capacitor is released to the laser, causing the laser to emit light. Therefore, this driving process takes a considerable amount of time. Furthermore, after the receiver receives the echo of the secondary laser, it outputs an echo signal. The back-end output circuit also takes a considerable amount of time to amplify, shape, and sample the echo signal, making it impossible to output the detection result immediately. Therefore, to maintain the lidar's point frequency, this solution uses the detection results of the secondary laser in the current detection cycle to determine the operating mode of the primary laser in the next detection cycle. If the laser driving speed and the processing speed of the back-end output circuit can be improved, the above method of determining the operating mode of the primary laser for the corresponding channel in the current detection cycle based on the detection results of the secondary laser in the current detection cycle can also be used.

[0057] Third, the primary laser's operating modes include short-range and long-range modes. In the short-range mode, the primary laser's emission power is low, less than that of the secondary laser. In the long-range mode, the primary laser's emission power is high, far exceeding that of the secondary laser. When using the aforementioned charging, energy transfer, and enabling drive circuits, the charging time for the primary laser in the short-range mode is much shorter than that in the long-range mode.

[0058] Furthermore, in the above embodiment, based on the detection results of multiple secondary laser beams, the operating mode of the primary laser beam of each corresponding channel is determined as follows: if the detection result of the secondary laser beam of a channel indicates that no echo laser beam is received or the time when the reflected laser beam is received is greater than a third time, the primary laser beam of the channel is determined to be in the long-range operating mode; if the detection result of the secondary laser beam of a channel indicates that the time when the transmitted laser beam is received is less than or equal to the third time, the primary laser beam of the channel is determined to be in the short-range operating mode. In the above embodiment, the third time is the time when the preamble signal is quenched when the primary laser beam detection period is in the long-range mode.

[0059] The detection results of the secondary lasers of the above-mentioned multiple channels can be achieved through steps S301 to S303.

[0060] Step S301: determining whether a reflected signal is identified in the echo signal, where the reflected signal is the laser light that is reflected from the secondary laser beam emitted to the detection area and then returned.

[0061] If there is a target object within the maximum detection range of the secondary laser, the laser radar receiver will receive the echo laser, which includes the reflected laser and stray light returned after the secondary laser is reflected by the target object, and output the corresponding reflection signal and leading signal; therefore, the echo signal output in the secondary period includes the reflection signal and the leading signal.

[0062] Step S302: If no reflected signal is identified, the detection result is determined based on the waveform characteristics of the leading signal of the secondary laser.

[0063] If the reflected signal is not recognized, there are two situations: one is that the receiver receives the reflected laser of the secondary laser, but the reflected signal output by the receiver is superimposed on the leading signal, and the back-end output circuit cannot distinguish the reflected signal of the secondary laser; the other is that the target object is beyond the ranging range, and the receiver does not receive the reflected laser of the secondary laser. The receiver does not output a reflected signal, only a leading signal.

[0064] Specifically, as one embodiment of the present application, determining a detection result based on the waveform characteristics of the leading signal of the secondary laser light may include: obtaining a characteristic difference between the waveform characteristics of the leading signal of the secondary laser light and a preset waveform characteristic, and comparing the characteristic difference with a preset threshold; if the absolute value of the characteristic difference exceeds the preset threshold, determining that the time of receipt of the reflected laser light of the secondary laser light is earlier than the fourth time; that is, the detection result of the secondary laser light is that the time of receipt of the echo laser light is less than the third time. If the absolute value of the characteristic difference is less than or equal to the preset threshold, determining that the detection result of the secondary laser light is that the reflected laser light of the secondary laser light is not received.

[0065] In the above embodiment, the preset waveform characteristics can be obtained by calibrating the leading signal of the laser radar. By comparing the received leading signal with the waveform characteristics of the leading signal obtained in advance, it can be determined whether there is an overlapping reflection signal.

[0066] Therefore, after the second laser is emitted in the current detection cycle, if the characteristic difference between the waveform characteristics of the leading signal output by the receiver and the preset waveform characteristics exceeds the preset threshold, it means that an indistinguishable reflected signal is overlapped in the leading signal, causing a significant change in the waveform characteristics of the leading signal; indicating that the receiver has received the reflected laser, and the time of receiving the reflected laser is earlier than the fourth moment. When the time of receiving the reflected laser is earlier than the fourth moment, the reflected signal and the leading signal are too close to overlap and cannot be distinguished. If the characteristic difference between the waveform characteristics of the leading signal output by the receiver and the preset waveform characteristics does not exceed the preset threshold, it means that the received echo signal is the leading signal, there is no reflected signal, and therefore no reflected laser is received.

[0067] The waveform feature may be a pulse width, specifically, the pulse width of the leading signal being greater than a preset threshold. The waveform feature may also be an amplitude, specifically, the amplitude of the leading signal being greater than a preset threshold. The waveform feature may also be a waveform area, specifically, the waveform area of the leading signal being greater than a preset threshold. The increase in waveform area may be caused by changes in amplitude and / or pulse width.

[0068] Step S303: If a reflected signal is identified, a detection result is determined according to the reception time of the reflected signal.

[0069] If the back-end output circuit can identify the reflected signal, it means that two waveforms were sampled in the secondary analysis area: the leading signal and the reflected signal of the secondary laser. The reflected laser was received later than the fourth moment, and the reflected laser reception time can be calculated based on the sampling time of the reflected signal. The reflected laser reception time is obtained based on the sampling time of the reflected signal, and the detection result of the secondary laser is thus determined.

[0070] When the reflected laser reception time is less than or equal to the third moment, the reflected laser reception time of the secondary laser is between the fourth moment and the third moment, and the reflected signal does not overlap with the leading signal of the secondary laser, but still overlaps with the leading signal of the main laser in the long-distance mode. The target object is located within the near-field blind zone of the main detection cycle in the long-distance mode, for example, the near-field blind zone of the main detection cycle in the long-distance mode is 0 to 15 meters. When the reflected laser reception time is greater than the third moment, the reflected laser reception time of the secondary laser is greater than the third moment, and the reflected signal neither overlaps with the leading signal of the secondary laser nor with the leading signal of the main laser in the long-distance mode. Therefore, the target object is located in the far-field area, for example, the target area is located in the far-field area ranging from 15 to 200 meters.

[0071] When the detection result of the secondary laser is that no reflected laser is received or the time when the reflected laser is received is greater than the third time, the main laser is determined to adopt the long-distance working mode to obtain the strongest detection capability and further detect target objects at a farther distance or objects with low reflectivity. The emission power of the main laser in the long-distance working mode is much greater than the emission power of the secondary laser. Generally speaking, the emission power of the main laser in the long-distance mode is the maximum emission power of the lidar, usually full power. In addition, the detection result of the secondary laser shows that there is no reflected laser in the near-field area, such as the range of 2 to 20m, which can rule out the possibility of people in this distance range. The main laser adopts the long-distance working mode to ensure the ranging capability of the lidar. For example, the maximum detection distance of the lidar needs to reach 200m, and it also ensures eye safety and prevents people from emitting high-power outgoing lasers in the near-field area.

[0072] If the reflected laser light is received at a time equal to or less than the third moment, the target object is located within the near-field blind spot of the primary laser in long-range mode, confirming that the primary laser is operating in short-range mode. To accurately detect targets at even closer distances, the primary laser's transmit power must be lower than that of the secondary laser. This further reduces stray light; small amounts of stray light do not excite the receiver, and the receiver does not output a pilot signal. This prevents the pilot signal from affecting near-field detection and enables accurate detection of targets within a range of 0 to 2 meters. Therefore, the primary laser operates in short-range mode, and the transmit power of the primary laser in short-range mode is lower than that of the secondary laser. For example, the detection range of the primary laser in short-range mode is 0 to 10 meters.

[0073] The main laser uses a channel in remote operating mode, and code modulation is used to control the emission of the main laser in that channel. Since the main laser in remote operating mode has the highest emission power, the corresponding main remote analysis area is the longest. If each channel were still required to emit the main laser sequentially, with an interval greater than the main remote analysis area, to address crosstalk between channels, the time taken would certainly exceed the detection cycle, reducing the system frame rate. Therefore, code modulation is used to control the emission of the main laser. Specifically, the following steps can be performed: obtaining a second moment, which is the start of a code area of random length; after the code area ends, the control channel begins charging the main remote; after the main remote charging ends, the channel begins switching the main remote; after the channel switching ends, the control channel begins enabling the main remote, and the channel emits the main laser. The second moment can be the start signal of the multi-channel lidar's galvanometer, for example, outputting a clock signal every time the galvanometer rotates through a fixed angle. The second moment can also be generated by the multi-channel lidar's clock module, for example, outputting a clock signal at fixed intervals. The second moment is used as a reference, and a delay is added before the main laser is emitted. This delay is the coding area, and the length of the coding area is the delay. Since the laser radar calculates the distance by calculating the time it takes to receive the reflected laser and emit the outgoing laser, the delay can be eliminated by subtracting the receiving time from the transmitting time, resulting in an accurate detection distance. Adjacent detection cycles basically detect the same object, and the detection distance obtained is the same. However, the interference light from other channels has a different delay than the delay of this channel, and the detection distance obtained after calculation will change significantly, which can then identify the interference light and achieve an anti-interference effect. The coding area has a maximum duration set, for example, it can be 200ns, and the length of the coding area can be any value between 0 and 200ns.

[0074] The main laser in the close-range working mode has the lowest emission power, and the corresponding main close-range analysis zone is the shortest. The length of the main close-range analysis zone is the fourth preset time, which is less than the second preset time. Because the main laser uses the channel in the long-range working mode (the main far channel), its main far charging time is very long, while the main laser uses the channel in the close-range working mode (the main near channel), its main near charging and main close analysis zone occupy very short time. When the main near channel has completed a transmission and reception detection, the main far channel is still in the main far charging state, so there is no channel crosstalk between the main transmission channel and the main close channel.

[0075] The main laser uses a channel in close-range operating mode, emitting the main laser at a preset reference time for that channel. Specifically, the following steps may be performed: obtaining a second time, controlling the channel to begin main close-range charging at that time; when main close-range charging completes, initiating main close-range switching of the channel; and after the main close-range switching of the channel completes, initiating main close-range enabling at the preset reference time, emitting the main laser. The main close-range analysis zone is very short, controlling the main lasers of all main close-range channels to fire sequentially, with an interval greater than the main close-range analysis zone, to avoid crosstalk between multiple main close-range channels during the main detection cycle.

[0076] However, for a certain channel, the operating mode of the main laser is constantly adjusted and changed according to the detection results of the secondary laser. The main laser of the current detection cycle adopts the short-range working mode, and the main laser of the next detection cycle may change to the long-range working mode. If all the main near-range channels need to be identified in each working cycle of the multi-channel lidar and the main lasers of these main near-range channels are controlled to be emitted in sequence at a certain time interval, the control difficulty will be greatly increased. Therefore, each channel is preset with a reference time, and the time interval between the reference times of adjacent channels is the third preset time. The third preset time is greater than or equal to the fourth preset time. With this setting, for a certain channel, the main laser of any detection cycle adopts the short-range working mode and emits the main laser at its preset reference time. The main near-range analysis area will not overlap with other channels and cause crosstalk; for the multi-channel lidar, the main near-range channel only needs to control the emission of the main laser at its preset reference time, which facilitates the simplification of system control.

[0077] Taking the aforementioned multi-channel laser radar with 5 channels (i.e. CH1 to CH5) as an example, combined with Figure 3a and Figure 3b , further explaining the emission control of the main laser under different working modes.

[0078] like Figure 3aAs shown, CH1, CH2, CH3, CH4, and CH5 all have preset reference times: the first reference time (T1), the second reference time (T2), the third reference time (T3), the fourth reference time (T4), and the fifth reference time (T5). The time interval between the first reference time and the second reference time is the third preset time (represented by t3 in the figure). The time interval between the second reference time and the third reference time is also the third preset time. Similarly, the time interval between the fourth reference time and the fifth reference time is also the third preset time. If the main lasers of CH1 to CH5 all adopt the close-range working mode, each channel will emit the main laser in sequence with the emission interval greater than the length of the main close-range analysis zone. No crosstalk will occur during the five main detection cycles.

[0079] At the same time, the total time taken to add up the master near charging, master near switching, master near enabling of the five channels, and the third preset time occupied by the five channels is also less than the master far charging time. Therefore, there is no overlap between the master near analysis area and the master far analysis area, and the master detection cycles of the master near channel and the master far channel do not generate crosstalk.

[0080] For example, in a current working cycle of a multi-channel lidar, the main lasers of channels CH1, CH2, and CH5 adopt a long-distance working mode, while the main lasers of channels CH3 and CH4 adopt a short-distance working mode.

[0081] like Figure 3b As shown, when the main lasers of channels CH1, CH2, and CH5 adopt the long-distance working mode, the three channels all start encoding at the second moment of their respective detection cycles. After the delay of the coding area, they start the main long-distance charging, main long-distance conversion, and main long-distance enabling (charging, conversion, and enabling are briefly described in the figure respectively), and emit the main laser. The length of the coding area of each of the three channels is random. The main charging and main conversion time of the three channels are the same. The time of main long-distance enabling will vary due to the different lengths of the coding area, that is, the main laser emission time of the three channels is slightly earlier or later. When the main lasers of channels CH3 and CH4 adopt the short-distance working mode, both channels start the main short-distance charging and main short-distance conversion at the second moment of their respective detection cycles. After the conversion is completed, channel CH3 is mainly enabled at the third reference time and emits the main laser, and channel CH4 is mainly enabled at the fourth reference time and emits the main laser.

[0082] If the multi-channel lidar's next operating cycle uses the long-range mode for the main lasers of channels CH1 and CH4, while the short-range mode for the main lasers of channels CH2, CH3, and CH5, is used, channels CH1 and CH4 begin encoding at the second moment of their respective detection cycles. After a delay in the encoding zone, they begin charging the main long-range mode, switching the main long-range mode, and enabling the main long-range mode, emitting the main laser. The encoding zones of the two channels have different lengths. Channels CH2, CH3, and CH5 begin charging the main short-range mode and enabling the main short-range mode at the second moment of their respective detection cycles. Channel CH2 enables the main short-range mode to emit the main laser at the second reference moment, channel CH3 enables the main short-range mode to emit the main laser at the third reference moment, and channel CH5 enables the main short-range mode to emit the main laser at the fifth reference moment.

[0083] From the above Figure 2 From the control method of multi-channel laser emission, it can be seen that during the working cycle of the multi-channel laser radar, the emission of the secondary lasers of multiple channels of the multi-channel laser radar is controlled in a time-sharing manner. According to the detection results of the secondary lasers of multiple channels, the main laser is emitted or the emission of the main laser is coded and modulated at the reference time preset by the channel. The detection cycle of each channel of the laser radar includes a secondary cycle and a main cycle. The laser radar of multiple channels includes multiple secondary cycles and a main cycle. The duration of the working cycle of the laser radar is limited by the system frame rate. The emission of the secondary lasers of multiple channels is controlled in a time-sharing manner. The main laser is emitted or the emission of the main laser is coded and modulated at the reference time preset by the channel. This allows the secondary cycles and the main cycle of multiple channels to be separated in time, or the reflected laser of the channel to be identified through encoding and decoding. Therefore, channel crosstalk during the operation of the multi-channel laser can be prevented without increasing the cost.

[0084] See also Figure 4 , is a schematic diagram of the structure of a multi-channel laser emission control device shown in an embodiment of the present application. For ease of explanation, only the parts related to the embodiment of the present application are shown. Figure 4 The exemplary multi-channel laser emission control device mainly includes a first control module 401 and a second control module 402, wherein:

[0085] The first control module 401 is used to control the emission of secondary lasers of multiple channels of the multi-channel laser radar in a time-sharing manner during the working cycle of the multi-channel laser radar;

[0086] The second control module 402 is configured to emit a main laser or code-modulate the emission of the main laser at a preset reference time of the channel according to the detection results of the secondary lasers of the multiple channels.

[0087] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0088] From the above Figure 4 It can be seen from the control device of the multi-channel laser emission of the example that, during the working cycle of the multi-channel laser radar, the emission of the secondary lasers of the multiple channels of the multi-channel laser radar is controlled in a time-sharing manner, and the emission of the main laser or the emission of the code-modulated main laser is emitted at the reference time preset by the channel according to the detection results of the secondary lasers of the multiple channels. The detection cycle of each channel of the laser radar includes a secondary emission cycle and a main emission cycle. The laser radar of multiple channels includes multiple secondary emission cycles and a main emission cycle. The duration of the working cycle of the laser radar is limited by the system frame rate. The emission of the secondary lasers of multiple channels is controlled in a time-sharing manner, and the emission of the main laser or the emission of the code-modulated main laser is emitted at the reference time preset by the channel, so that the secondary emission cycles and the main emission cycles of the multiple channels can be separated in time, or the reflected laser of the channel can be identified by encoding and decoding, thereby preventing channel crosstalk during the operation of the multi-channel laser without increasing the cost.

[0089] Figure 5 It is a structural diagram of an electronic device shown in an embodiment of the present application.

[0090] See also Figure 5 , the electronic device 500 includes a memory 510 and a processor 520.

[0091] The processor 520 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0092] The memory 510 may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage. ROM may store static data or instructions required by the processor 520 or other modules of the computer. The permanent storage may be a readable and writable storage device. The permanent storage may be a non-volatile storage device that retains stored instructions and data even when the computer is powered off. In some embodiments, the permanent storage device uses a large-capacity storage device (e.g., a magnetic or optical disk, flash memory) as the permanent storage device. In other embodiments, the permanent storage device may be a removable storage device (e.g., a floppy disk, optical drive). The system memory may be a readable and writable storage device or a volatile readable and writable storage device, such as dynamic random access memory. The system memory may store some or all instructions and data required by the processor during operation. In addition, the memory 510 may include any combination of computer-readable storage media, including various types of semiconductor memory chips (e.g., DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and magnetic disks and / or optical disks may also be used. In some embodiments, the memory 510 may include a readable and / or writable removable storage device, such as a compact disc (CD), a read-only digital versatile disc (e.g., DVD-ROM, dual-layer DVD-ROM), a read-only Blu-ray disc, an ultra-density optical disc, a flash memory card (e.g., SD card, mini SD card, Micro-SD card, etc.), a magnetic floppy disk, etc. Computer-readable storage media do not include carrier waves and transient electronic signals transmitted wirelessly or wired.

[0093] The memory 510 stores executable codes. When the executable codes are processed by the processor 520 , the processor 520 may execute part or all of the above-mentioned methods.

[0094] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0095] Alternatively, the present application can also be implemented as a computer-readable storage medium (or non-transitory machine-readable storage medium or machine-readable storage medium) on which executable code (or computer program or computer instruction code) is stored. When the executable code (or computer program or computer instruction code) is executed by a processor of an electronic device (or server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0096] The embodiments of the present application have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for controlling multi-channel laser emission, characterized in that: The method comprises: During the working cycle of the multi-channel laser radar, time-sharing control is used to transmit the secondary lasers of multiple channels of the multi-channel laser radar; According to the detection results of the secondary lasers of the multiple channels, emitting a main laser or coding and modulating the emission of the main laser at a preset reference time of the channel; The emitting a main laser or code-modulating the emission of the main laser at a preset reference time of the channel according to the detection results of the secondary lasers of the multiple channels includes: determining the working mode of the main laser of the corresponding channel according to the detection results of the secondary lasers to obtain the working mode of the main lasers of all the channels; if the main laser of the channel adopts a short-range working mode, emitting the main laser at the preset reference time of the channel; if the main laser of the channel adopts a long-range working mode, code-modulating the emission of the main laser; The coding and modulating the emission of the main laser include: obtaining a second moment, where the second moment is the start of a coding area, and the length of the coding area is random; controlling the channel to start main remote charging after the end of the coding area; starting the main remote conversion of the channel after the end of the main remote charging; and controlling the channel to start main remote enabling after the end of the main remote conversion of the channel, so that the channel emits the main laser.

2. The control method for multi-channel laser emission according to claim 1, characterized in that: The time-sharing control of the emission of secondary lasers of multiple channels of the multi-channel laser radar includes: The laser sub-emission intervals of the multiple channels are controlled to be a first preset time for emission.

3. The control method for multi-channel laser emission according to claim 2, characterized in that: The controlling the multiple channels to emit laser light at intervals of a first preset time includes: At a first moment, controlling each of the channels to start charging for the second time; When the secondary energy charging is completed, the secondary energy conversion of each channel is started; After the secondary enabling of each channel is completed, each channel is controlled in turn to start secondary enabling, and the channel emits the secondary laser, and the secondary enabling moments of adjacent channels are separated by a first preset time.

4. The control method for multi-channel laser emission according to claim 3, characterized in that: The method further comprises: The length of the secondary analysis area of each channel is a second preset time, and the first preset time is greater than or equal to the second preset time.

5. The control method for multi-channel laser emission according to claim 1, characterized in that: The determining the operating mode of the primary laser of the corresponding channel according to the detection result of the secondary laser light to obtain the operating modes of the primary laser light of all the channels includes: If the detection result of the secondary laser of the channel is that no reflected laser is received or the time when the reflected laser is received is greater than the third time, it is determined that the primary laser of the corresponding channel adopts the long-distance working mode; If the detection result of the secondary laser of the channel is that the time of receiving the reflected laser is less than or equal to the third time, it is determined that the primary laser of the corresponding channel adopts the close-range working mode.

6. The control method for multi-channel laser emission according to claim 1, characterized in that: The emitting the main laser at a reference time preset in the channel includes: Obtaining a second moment, and controlling the channel to start main near charging at the second moment; When the main near energy charging is completed, the main near energy conversion of the channel is started; After the main proximity switching of the channel is completed, the main proximity enabling is started at a reference time preset in the channel, and the channel emits the main laser; Each of the channels is preset with the reference time, and the reference times corresponding to adjacent channels are separated by a third preset time interval.

7. The control method for multi-channel laser emission according to claim 6, characterized in that: The method further comprises: The length of the main analysis zone in the close-range working mode is a fourth preset time, and the third preset time is greater than or equal to the fourth preset time.

8. A multi-channel laser emission control device, characterized in that: The device comprises: A first control module is used to control the emission of secondary lasers of multiple channels of the multi-channel laser radar in a time-sharing manner during a working cycle of the multi-channel laser radar; A second control module is configured to emit a main laser or code-modulate the emission of the main laser at a preset reference time of the channel according to the detection results of the secondary lasers of the multiple channels; The emitting a main laser or code-modulating the emission of the main laser at a preset reference time of the channel according to the detection results of the secondary lasers of the multiple channels includes: determining the working mode of the main laser of the corresponding channel according to the detection results of the secondary lasers to obtain the working mode of the main lasers of all the channels; if the main laser of the channel adopts a short-range working mode, emitting the main laser at the preset reference time of the channel; if the main laser of the channel adopts a long-range working mode, code-modulating the emission of the main laser; The coding and modulating the emission of the main laser include: obtaining a second moment, where the second moment is the start of a coding area, and the length of the coding area is random; controlling the channel to start main remote charging after the end of the coding area; starting the main remote conversion of the channel after the end of the main remote charging; and controlling the channel to start main remote enabling after the end of the main remote conversion of the channel, so that the channel emits the main laser.

9. An electronic device, characterized in that: include: processor; as well as A memory having executable codes stored thereon, which, when executed by the processor, causes the processor to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having executable codes stored thereon, wherein when the executable codes are executed by a processor of an electronic device, the processor is caused to execute the method according to any one of claims 1 to 7.

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