A laser ranging method, device, equipment and storage medium

Abstract

The application provides a laser ranging method, device and equipment and a storage medium, relates to the technical field of laser radar, and can effectively reduce the data bandwidth occupation during TDC value transmission. The method comprises the following steps: detecting a return signal of a laser pulse signal in a period to obtain a plurality of trigger signals; converting each trigger signal into a TDC value; selecting a target TDC value in the period; the target TDC value is a TDC value in the period; generating a time histogram based on the target TDC value in one or more continuous periods; and obtaining ranging information by processing the time histogram. The application can be used in the process of laser radar ranging.

Description

Technical Field

[0001] This application relates to the field of lidar technology, and in particular to a laser ranging method, apparatus, device and storage medium. Background Technology

[0002] In recent years, with the continuous development of artificial intelligence technology, the demand for intelligent devices has been increasing. AI technologies, represented by autonomous driving, have been widely applied, providing great convenience to people's lives and work. The application of intelligent devices has enormous commercial and social value. LiDAR is a key sensor in autonomous driving; it is a sensor that uses the diffuse reflection of laser light from objects to achieve high-precision distance measurement.

[0003] LiDAR ranging technology is primarily based on the direct time-of-flight (dTOF) ranging scheme. This technology periodically emits laser pulses, which are then emitted onto the surface of an object to generate echo signals that return. A single-photon avalanche diode (SPAD) periodically detects these echo signals to obtain trigger signals. A time-to-digital converter (TDC) converts each trigger signal from the SPAD into a TDC value, which is then transmitted to a processing device. The processing device uses the histogram data of the TDC values ​​to obtain the distance information, thus determining the distance from the measurement point to the object.

[0004] To avoid the impact of "histogram stacking" on ranging performance, the industry typically employs multi-event TDC sampling to record the SPAD's trigger signals. This involves recording and transmitting the TDC values ​​of multiple trigger signals from the SPAD within each cycle. However, this approach requires transmitting a large number of TDC values ​​per cycle, resulting in enormous bandwidth demands for data transmission, making such massive data transmission technically difficult to achieve. Summary of the Invention

[0005] This application provides a laser ranging method, apparatus, device, and storage medium that can effectively reduce the data bandwidth usage during TDC value transmission.

[0006] In a first aspect, this application provides a laser ranging method, which includes: detecting the echo signal of a laser pulse signal within a period to obtain multiple trigger signals; converting each trigger signal into a Time Data Converter (TDC) value; selecting a target TDC value for the period, wherein the target TDC value is a TDC value within the period; generating a time histogram based on the target TDC value within one or more consecutive periods; and processing the time histogram to obtain ranging information.

[0007] In one possible implementation, the method further includes: counting each trigger signal within a period; the target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence.

[0008] In another possible implementation, the method further includes counting the TDC value of each trigger signal transition within a period. The target TDC value is the nth TDC value in the counting sequence.

[0009] In another possible implementation, n is a random number between the minimum and maximum values ​​in the counting order.

[0010] In another possible implementation, the above method further includes: determining a global random number for the period; the global random number is a random number between 1 and a preset parameter; the preset parameter is used to indicate the maximum count value of the trigger signal for all periods; and determining n based on the counting order, the preset parameter, and the global random number.

[0011] In another possible implementation, n is determined based on the counting order, preset parameters, and global random numbers, including: using the product of the ratio of the maximum value of the counting order to the preset parameters and the global random number as n.

[0012] In another possible implementation, the method further includes counting the cycles. Here, n is the value of either the counting order of the trigger signals or the counting order of the cycles, provided that the counting order of the trigger signals is equal to the counting order of the cycles.

[0013] In another possible implementation, the method further includes: if the maximum value of the counting sequence of the trigger signal is less than the counting sequence of the period, determining the maximum value as n and resetting the counting of the period.

[0014] The laser ranging method provided in this application detects the echo signal within a period, obtains the trigger signal, and converts it into a Time-Cost Distance (TDC) value. In each period, only one target TDC value is selected, and a time histogram is generated based on the target TDC value for each period to obtain ranging information. Compared to traditional multi-event TDC schemes, this application transmits only one TDC value per period, effectively reducing the amount of data transmitted per period and minimizing data bandwidth usage.

[0015] Secondly, this application provides a laser ranging device, which includes: a detection module, a conversion module, a selection module, and a processing module; the detection module is used to detect the echo signal of a laser pulse signal within a period to obtain multiple trigger signals; the conversion module is used to convert each trigger signal into a Time Data Converter (TDC) value; the selection module is used to select a target TDC value for a period, wherein the target TDC value is a TDC value within the period; the processing module is used to generate a time histogram based on the target TDC value within one or more consecutive periods, and process the time histogram to obtain ranging information.

[0016] In one possible implementation, the above-mentioned device further includes: a counting module; the counting module is used to count each trigger signal within a period; the target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence.

[0017] In another possible implementation, n is a random number between the minimum and maximum values ​​in the counting order.

[0018] In another possible implementation, the above-mentioned device further includes: a determining module; the determining module is used to determine a global random number for the period; the global random number is a random number between 1 and a preset parameter; the preset parameter is used to indicate the maximum count value of the trigger signal for all periods. The determining module is also used to determine n based on the counting order, the preset parameter, and the global random number.

[0019] In another possible implementation, the determining module is specifically used to multiply the ratio of the maximum value of the counting order to the preset parameter and the global random number as n.

[0020] In another possible implementation, the counting module is also used to count the cycles; n is the value of the counting order of the trigger signals or the value of the counting order of the cycles when the counting order of the trigger signals is equal to the counting order of the cycles.

[0021] In another possible implementation, the determining module is also used to determine the maximum value as n and reset the count of the period if the maximum value of the counting sequence of the trigger signal is less than the counting sequence of the period.

[0022] Thirdly, this application provides a lidar system, comprising: a laser pulse transmitter, a laser pulse detector, and a processor; the laser pulse transmitter is used to transmit laser pulse signals; the laser pulse detector is used to detect the echo signals of the laser pulse signals within a period to obtain multiple trigger signals; the processor is used to convert each trigger signal into a time-data converter (TDC) value; select a target TDC value for the period; the target TDC value is a TDC value within the period; based on the target TDC values ​​within one or more consecutive periods, generate a time histogram, and process the time histogram to obtain ranging information.

[0023] In one possible implementation, the laser pulse detector includes a single-photon avalanche diode (SPAD); the SPAD is used to detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals.

[0024] Fourthly, this application provides an electronic device comprising: a processor and a memory; the memory storing processor-executable instructions; when the processor is configured to execute the instructions, causing the electronic device to implement the method of the first aspect described above.

[0025] Fifthly, this application provides a computer-readable storage medium comprising: computer software instructions; which, when executed in an electronic device, cause the electronic device to implement the method described in the first aspect.

[0026] In a sixth aspect, this application provides a computer program product that, when run on a computer, causes the computer to perform the steps of the relevant method described in the first aspect above, so as to implement the method of the first aspect above.

[0027] The beneficial effects of the second to sixth aspects mentioned above can be referred to the corresponding descriptions in the first aspect, and will not be repeated here. Attached Figure Description

[0028] Figure 1 A schematic diagram of a photon sampling histogram provided in this application;

[0029] Figure 2 A schematic diagram of the composition of a lidar system provided in this application;

[0030] Figure 3 A schematic flowchart of a laser ranging method provided in this application;

[0031] Figure 4 A flowchart illustrating one embodiment of this application;

[0032] Figure 5 This application provides a schematic diagram of a process for randomly selecting TDC values;

[0033] Figure 6 A flowchart illustrating an embodiment 2 provided in this application;

[0034] Figure 7 This application provides another flowchart for randomly selecting TDC values;

[0035] Figure 8 A flowchart illustrating an embodiment 3 of this application;

[0036] Figure 9 This application provides a flowchart illustrating the sequential selection of TDC values.

[0037] Figure 10 This application provides a schematic diagram of the composition of a laser ranging device;

[0038] Figure 11 This is a schematic diagram of the composition of an electronic device provided in this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] It should be noted that in the embodiments of this application, the words "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design scheme described as "exemplarily" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0041] To facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish the same or similar items with essentially the same function and effect. Those skilled in the art can understand that the terms "first" and "second" are not intended to limit the quantity or execution order.

[0042] SPAD-based dTOF ranging schemes have great potential for long-distance detection due to SPAD's single-photon-level sensitivity, enabling it to detect extremely weak target signals. The basic principle of dTOF ranging is that after a laser pulse signal is emitted to illuminate the target object, the SPAD detects and receives the returned photons, and records the time information after TDC conversion. However, due to the influence of ambient light and dark counting, SPADs may experience false triggers, so the TDC value obtained from a single laser measurement may not be accurate. To improve measurement reliability, it is usually necessary to repeatedly emit laser pulses and record the corresponding time information. All time information is then compiled into a time histogram. Analyzing the time histogram yields the final target flight time, which is multiplied by the speed of light to convert into the corresponding distance information.

[0043] The applicant's research found that when the dTOF detection method uses TDC to convert the SPAD-triggered signal, if only the TDC value corresponding to the first trigger signal is recorded and retained in each cycle, this method is called "first photon" detection. For example... Figure 1 The photon sampling histogram shown illustrates this. Because the "first photon" detection scheme only records the first trigger signal, in strong ambient light conditions, the SPAD is easily triggered and recorded at the very beginning of the cycle. Therefore, the histogram eventually exhibits an exponential distribution trend, with "stacking" in the first half, leading to a decrease in the probability of detecting distant objects. Conversely, there is the "tail photon" detection scheme, which records and retains only the TDC value corresponding to the last trigger signal in each cycle, such as... Figure 1 As shown, this scheme results in "stacking" in the latter half of the histogram. Therefore, while the "tail photon" detection scheme is advantageous for detecting distant objects, it has a negative effect on close-range targets.

[0044] To address the aforementioned histogram "stacking" phenomenon, a multi-event TDC can be used to sample and record the trigger signal. This method allows detection to be performed in environments with strong ambient light, such as... Figure 1 As shown, this scheme can effectively alleviate the histogram "stacking" phenomenon. However, since multiple TDC values ​​need to be recorded and transmitted in each cycle, the demand for data transmission bandwidth is greater. The estimated data transmission bandwidth is: measurement repetition frequency × chip array size × number of TDC values ​​triggered in one cycle × storage size of one TDC value, where the chip array size affects the imaging resolution, and the measurement repetition frequency affects the refresh rate of the imaging system. At a large chip array size, such as a quarter videographics array (QVGA) resolution, and a certain measurement repetition frequency (MHz), the data transmission bandwidth required for multi-event TDC can reach hundreds or thousands of Gbps, making it technically difficult to implement.

[0045] To ensure that the dTOF ranging scheme has strong resistance to ambient light while reducing the data transmission bandwidth requirement, this application provides a laser ranging method. In each cycle, instead of recording only a certain number of events, it samples one event number according to a rule. The rule for selecting which event number can be in various ways, such as random or sequential.

[0046] Since ambient light is uniform along the time axis, the histogram obtained from random sampling of ambient light is theoretically also uniform along the time axis, without any "stacking" phenomenon. However, for object signals, their positions are fixed, and their signal intensity is greater than that of ambient light. Therefore, the probability of sampling at that time point is higher than that of ambient light at other times, which is reflected in the histogram as a higher height at that time point compared to other times. The final histogram shape is basically similar to the aforementioned multi-event sampling histogram, except that the overall height decreases. Therefore, the laser photon sampling method provided in this application embodiment possesses both the ambient light resistance capability of multi-event sampling and can reduce data bandwidth usage.

[0047] Figure 2 This is a schematic diagram illustrating the composition of a lidar system provided in an embodiment of this application. Figure 2 As shown, the system includes a laser pulse emission module, a detection module, a random sampling module, and a data processing module. The laser pulse emission module periodically emits laser pulses, which return as echo signals after illuminating the object surface. The SPAD in the detection module detects the echo signals, generating multiple trigger signals in each cycle, including ambient light trigger, valid object signal trigger, and dark count trigger. The Time-Digital Distance Detection (TDC) module converts the SPAD's trigger signals into corresponding time information, i.e., TDC values. The random sampling module then selects one of these TDC values, records it, and transmits it to the subsequent data processing module. The data processing module performs time histogram statistics on the TDC values ​​transmitted in each cycle, extracts peak values, and finally converts them into corresponding distance information. The laser ranging method provided in this application embodiment is mainly implemented through the aforementioned detection module, random sampling module, and data processing module.

[0048] The laser ranging method provided in this application can be executed by a laser ranging device. This laser ranging device can also be referred to as the aforementioned random sampling module. For example, the laser ranging device can be multiple servers, including a server cluster, a single server, or a computer. Alternatively, the laser ranging device can be a chip, circuit board, microcontroller, or hardware card installed within the server. This embodiment does not limit the specific device form of the laser ranging device.

[0049] Figure 3 This is a schematic flowchart of a laser ranging method provided in an embodiment of this application.

[0050] It should be noted that the process of transmitting signal data by the laser ranging device is the same in each cycle. This application embodiment only describes the process of transmitting signal data within one cycle; other processes will not be elaborated upon. For example... Figure 3 As shown, the laser ranging method provided in this application may specifically include the following steps:

[0051] S301. The laser ranging device detects the echo signal of the laser pulse signal within a period and obtains multiple trigger signals.

[0052] As mentioned earlier, when lidar ranging is required, the laser pulse emission module in the lidar system can send a laser pulse signal, which, after illuminating the surface of an object, returns to form an echo signal. The laser ranging device in the lidar system detects and processes the echo signal. Therefore, in some embodiments, the laser ranging device can detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals.

[0053] Specifically, in a laser ranging device, the SPAD can detect the echo signal, and the SPAD detection generates multiple trigger signals.

[0054] S302, The laser rangefinder converts each trigger signal into a TDC value.

[0055] In some embodiments, after receiving multiple trigger signals, the laser ranging device can convert each trigger signal into a Time-Digital Converter (TDC) value. Specifically, the TDC in the laser ranging device is a module that can identify the time of event occurrence and convert analog signals into digital signals. Therefore, the TDC can convert each trigger signal into a TDC value, which is then transmitted to the data processing module for time histogram statistics to extract distance information.

[0056] For example, the converted TDC value can be stored in the storage module of the laser rangefinder.

[0057] S303, The laser rangefinder selects the target TDC value for the period.

[0058] The target TDC value is a TDC value within a period.

[0059] It should be noted that the strategy for selecting the target TDC value in S303 can be configured according to actual needs, and this application embodiment does not limit this.

[0060] In one possible implementation, S303 can be implemented according to the following... Figure 4In the illustrated embodiment, the TDC value obtained by converting the nth trigger signal in the counting sequence is used as the target TDC value for the current period. The specific implementation can be found in [reference needed]. Figure 4 The illustrative embodiments are not described in detail here.

[0061] In another possible implementation, S303 can be implemented as follows: Figure 6 In the illustrated embodiment, the value of n is determined based on a global random number, and then the TDC value obtained by converting the nth trigger signal in the counting sequence is used as the target TDC value for the current period. The specific implementation can be found in [reference needed]. Figure 6 The illustrative embodiments are not described in detail here.

[0062] In another possible implementation, S303 can be implemented according to the following... Figure 8 In the illustrated embodiment, the target TDC value is selected based on the count value n of the current period. Furthermore, the TDC value obtained from the conversion of the nth trigger signal in the counting sequence is used as the target TDC value for the current period. The specific implementation can be found in [reference needed]. Figure 8 The illustrative embodiments are not described in detail here.

[0063] As mentioned earlier, existing multi-event TDC schemes transmit multiple TDC values ​​per cycle, resulting in significant bandwidth consumption. Therefore, in this embodiment, the laser ranging device selects one TDC value within the cycle as the target TDC value and transmits it, so that the data processing module can receive the transmitted TDC value for ranging operations. The specific selection method can be random or sequential, as described in Embodiments 1-3 below.

[0064] S304. The laser ranging device generates a time histogram based on the target TDC value within one or more consecutive periods, and processes the time histogram to obtain ranging information.

[0065] In some embodiments, the laser ranging device continuously selects one or more consecutive periodic target TDC values, and statistically analyzes these consecutive periodic TDC values ​​to form a... Figure 1 The time histogram shown is an example of a multi-event sampling histogram. The vertical axis of this time histogram reflects the number of triggering events at a certain time scale. Since the position of the target being ranged is relatively fixed and the triggering signal corresponding to the target is also relatively stable, the time scale corresponding to the histogram with the highest height in this time histogram is determined as the flight time of the target being ranged. Multiplying this flight time by the speed of light yields the ranging information.

[0066] The technical solutions provided by the above embodiments bring at least the following beneficial effects: The laser ranging method provided in this application detects the echo signal within a period, obtains the trigger signal, and converts it into a TDC value. Only one target TDC value is selected in each period. Compared with the traditional multi-event TDC scheme, this application transmits only one TDC value per period, which can effectively reduce the amount of data transmitted per period and reduce the data bandwidth usage.

[0067] The method for selecting the target TDC provided in this application will be described in detail below with reference to specific embodiments. Depending on the selection method, this application provides the following three embodiments. For S304 above, the implementation method is the same in the three embodiments, therefore, it will not be repeated in the following embodiments. The following mainly describes each embodiment in conjunction with S301-S303 above.

[0068] Figure 4 This is a flowchart illustrating one embodiment of this application. Figure 4 As shown, it includes the following S401-S404.

[0069] S401. The laser ranging device detects the echo signal of the laser pulse signal within a period and obtains multiple trigger signals.

[0070] The description of this step is the same as the description of S301 above, and will not be repeated here.

[0071] S402, The laser rangefinder converts each trigger signal into a TDC value.

[0072] The description of this step is the same as the description of S302 above, and will not be repeated here.

[0073] S403, The laser rangefinder counts each trigger signal within a cycle.

[0074] In some embodiments, the laser rangefinder can count each trigger signal within a period, or in other words, count the TDC value converted from each trigger signal, to facilitate the subsequent selection of the target TDC value.

[0075] It should be noted that the laser rangefinder can also count other items within the period, as long as the target TDC value can be the nth TDC value. The specific implementation of this application is not limited.

[0076] Specifically, the laser rangefinder can use a counter to count the trigger signal or the TDC value; that is, the counter value is incremented by 1 each time a trigger signal or TDC value is obtained.

[0077] S404. The laser ranging device selects the target TDC value of the period. The target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence.

[0078] Where n is a random number between the minimum and maximum values ​​in the counting order.

[0079] In some embodiments, the laser ranging device can transmit the TDC value obtained by converting the nth trigger signal in the counting sequence as the target TDC value for the current period for ranging operations, etc. Here, n is a random number between the minimum and maximum values ​​of the counting sequence of the trigger signals within the period. Furthermore, when counting TDC values ​​in S403, the target TDC value is the nth TDC value in the counting sequence; this embodiment does not limit this.

[0080] Figure 5 This is a schematic diagram illustrating a process for randomly selecting TDC values, provided as an embodiment of this application. (Combined with...) Figure 5 right Figure 4 Example 1 is described in full. For each pixel, after the start of the measurement cycle, the SPAD detects the echo signal of the laser pulse signal, triggering the generation of multiple trigger signals and converting them into TDC values. For each trigger signal generated, the laser rangefinder caches its converted TDC value in the storage module, and the counter increments by 1. After the current measurement cycle ends, the laser rangefinder, through a random number generation circuit, generates a random number n1 between 1 and m1 based on the maximum and minimum values ​​of the counter's count sequence of the trigger signals. The n1th value in the storage module is transmitted as the target TDC value to the subsequent data processing module for use, and all TDC values ​​stored in the storage module for the current cycle are cleared, and the counter is reset. Then, the process is repeated in the next measurement cycle.

[0081] It is understood that in the above embodiment 1, each pixel requires a storage module, a random number generation circuit, and a counter. This is to achieve the random selection of a value from multiple TDC values ​​generated within a period for transmission and use.

[0082] Figure 6 This is a flowchart illustrating one embodiment 2 of this application. Figure 6 As shown, it includes the following S601-S606.

[0083] S601. The laser ranging device detects the echo signal of the laser pulse signal within a period and obtains multiple trigger signals.

[0084] The description of this step is the same as the description of S301 above, and will not be repeated here.

[0085] S602, the laser rangefinder converts each trigger signal into a TDC value.

[0086] The description of this step is the same as the description of S302 above, and will not be repeated here.

[0087] S603, the laser rangefinder counts each trigger signal within a cycle.

[0088] The description of this step is the same as the description of S403 above, and will not be repeated here.

[0089] S604, Global random number for determining the period of the laser rangefinder.

[0090] The global random number is a random number between 1 and a preset parameter. This preset parameter can be a value set based on practical experience, used to indicate the maximum count value of the trigger signal for all cycles.

[0091] In some embodiments, in each cycle, the laser ranging device can determine a global random number for the current cycle based on preset parameters. Specifically, the laser ranging device can determine the global random number through a global random number generation circuit.

[0092] S605. The laser ranging device determines n based on the counting sequence, preset parameters, and a global random number.

[0093] Where n is used to select the target TDC value.

[0094] In some embodiments, after determining the global random number of the period, the laser ranging device can determine the value of n based on the counting order of the trigger signals within the period, a preset parameter, and the global random number. Specifically, the laser ranging device uses the product of the ratio of the maximum value of the counting order to the preset parameter and the global random number as the value of n.

[0095] S606. The laser ranging device selects the target TDC value of the period. The target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence.

[0096] In some embodiments, the laser ranging device can transmit the TDC value obtained by converting the nth trigger signal in the counting sequence, or transmit the nth TDC value as the target TDC value for the current period, for ranging operations, etc. The value of n is obtained by S605 described above.

[0097] Figure 7 This is a schematic diagram illustrating another process for randomly selecting TDC values, provided in an embodiment of this application. (In conjunction with...) Figure 7 right Figure 6The following is a complete description of Embodiment 2. In Embodiment 1, each pixel has its own independent random number generation circuit, which results in a large circuit area overhead and is difficult to implement in chip designs with large pixel arrays. Therefore, Embodiment 2 optimizes this by having all pixels share the same random number generation circuit. The specific process is as follows: The laser ranging device has only one set of random number generation circuits, which can be called the global random number generation circuit. After the measurement cycle begins, the global random number generation circuit generates a global random number n2 with a maximum range of a preset parameter m2. This preset parameter can be determined in advance based on practical experience, such as ensuring that the value of m2 is greater than the maximum count value of the trigger signals in all cycles. For a single independent pixel, the counter is incremented by 1 after each SPAD trigger, and the TDC value converted from the trigger signal is stored in the storage module. After the cycle ends, the random number n3 is obtained according to the formula: n3 = round(m3 / m2*n2), where m3 is the maximum count value of the counter, and round() is the rounding operation. After obtaining the random number n3, the n3rd value in the storage module is transmitted as the target TDC value to the subsequent data processing module. Finally, the storage module and the counter are reset. Then, the above process is repeated in the next measurement cycle.

[0098] It is understandable that, compared with Embodiment 1, Embodiment 2 only requires each pixel to share a single random number generation circuit. After some computation, a random number for each pixel can be obtained. That is, each pixel needs a storage module and a counter, and all pixels share a single random number generation circuit, effectively reducing the difficulty of chip circuit design.

[0099] Figure 8 This is a flowchart illustrating one embodiment 3 of this application. Figure 8 As shown, it includes the following S801-S805.

[0100] S801, the laser rangefinder counts the cycles.

[0101] In some embodiments, the laser rangefinder can count the cycles at the beginning of a cycle. Specifically, the laser rangefinder can use a counter to increment the value of the counter by 1 at the beginning of a new cycle.

[0102] S802, the laser ranging device detects the echo signal of the laser pulse signal within a period and obtains multiple trigger signals.

[0103] The description of this step is the same as the description of S301 above, and will not be repeated here.

[0104] S803, the laser rangefinder converts each trigger signal into a TDC value.

[0105] In some embodiments, after receiving a trigger signal, the laser ranging device can convert the trigger signal into a TDC value. Further, the laser ranging device can update and store the new TDC value in the storage module, overwriting the previously stored TDC value. Simply put, within a cycle, the storage module stores only one TDC value at a time. Under certain conditions, the currently stored TDC value is transmitted to the data processing module for ranging.

[0106] S804, the laser rangefinder counts each trigger signal within a cycle.

[0107] The description of this step is the same as the description of S403 above, and will not be repeated here.

[0108] S805. The laser ranging device selects the target TDC value of the period. The target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence.

[0109] In some embodiments, when the counting order of the trigger signal is equal to the counting order of the period, the value of the counting order of the trigger signal at this time (or the value of the counting order of the TDC value) or the value of the counting order of the period is taken as the above-mentioned n value. The laser ranging device can select the TDC value obtained by converting the nth trigger signal (or the nth TDC value) as the target TDC value for transmission, so as to perform ranging work, etc.

[0110] In this embodiment 3, there is also the following situation: if multiple cycles have been completed, and the current counting order of the cycles is greater than the maximum possible number of triggers in each cycle, then there will be no situation where the counting order of the trigger signals is equal to the counting order of the cycles. Therefore, in some other embodiments, when the maximum value of the counting order of the trigger signals is less than the counting order of the current cycle, the maximum value is determined to be n, so that the laser ranging device selects the TDC value obtained by converting the nth trigger signal as the target TDC value (or selects the unique TDC value stored in the storage module at this time), and resets the counting of the cycles so that it starts counting again from 1.

[0111] Figure 9 This is a schematic diagram illustrating a sequential selection of TDC values ​​provided in an embodiment of this application. (Combined with...) Figure 9 right Figure 8The following is a complete description of Embodiment 3. In Embodiments 1 and 2 above, the storage unit of each pixel also caches all TDC values ​​within the cycle, which still incurs circuit area overhead in chip circuit design. Based on this, the scheme of Embodiment 3 does not need to store all values, but only stores one TDC value at any given time. The specific process is as follows: After the measurement cycle begins, counter 1 is used to count the cycle (e.g., count to n4). Within the cycle, counter 2 is used to count each trigger signal (e.g., count to n5). The TDC value converted by each trigger signal is refreshed and stored in the storage module, and the count n5 of counter 2 is incremented by 1. It is determined whether the value n5 of counter 2 is equal to the value n4 of counter 1, or whether the cycle has ended. If so, the current TDC value stored in the storage module is output, which is the TDC value converted by the n4th or n5th trigger signal as described above. Then it is determined whether the value n5 of counter 2 is less than the value n4 of counter 1. If not, the value n4 of counter 1 is incremented by 1 and the next measurement cycle begins. If so, it means that the maximum value of the counting sequence of the trigger signals is less than the counting sequence of the current cycle. In this case, the value n4 of counter 1 is reset to 1, and the above steps are continued in the next cycle. Simply put, the method of selecting the target TDC value in this embodiment 3 is as follows: the TDC value corresponding to the first trigger signal is transmitted in the first cycle, the second TDC value is transmitted in the second cycle, and so on. The nth value is transmitted in the nth cycle until the number of TDC values ​​triggered in the mth cycle is less than m. Then, the last TDC value is transmitted, and the system is reset to record the first TDC value in the next cycle.

[0112] It is understandable that the sequential sampling method used in Embodiment 3 is probabilistically very similar to random sampling and can be considered a special type of random sampling. Compared with Embodiments 1 or 2, Embodiment 3 does not require storing all TDC values ​​in each cycle, but only needs to repeatedly store one TDC value, and does not require a random number generation circuit. Each pixel requires storage space for one TDC value, as well as two counters. One counter is used to count the cycles, and the other counter counts the trigger signals.

[0113] The technical solutions provided by the above embodiments bring at least the following beneficial effects: The laser ranging method provided in this application detects the echo signal within a period, obtains the trigger signal, and converts it into a TDC value. Only one target TDC value is selected in each period. Compared with the traditional multi-event TDC scheme, this application transmits only one TDC value per period, which can effectively reduce the amount of data transmitted per period and reduce the data bandwidth usage.

[0114] Furthermore, this application embodiment employs a random selection method, randomly selecting a TDC value for transmission in each cycle. Since the intensity of the object trigger signal is higher than that of ambient light, this random sampling method increases the probability of sampling the object trigger signal compared to the ambient light trigger signal. This results in a more prominent histogram for the object, while the histograms for other ambient light events are lower and more uniform. Therefore, this random sampling method not only possesses the resistance to ambient light in multi-event TDCs, avoiding "histogram stacking," but also reduces data bandwidth usage. Additionally, this application provides three different TDC value selection methods, allowing users to choose the appropriate method for chip circuit design based on actual needs, satisfying various application scenarios.

[0115] As can be seen, the above mainly describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, the embodiments of this application provide corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the modules and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0116] In an exemplary embodiment, this application also provides a laser ranging device. This laser ranging device may include one or more functional modules for implementing the laser ranging method of the above method embodiments.

[0117] For example, Figure 10 This is a schematic diagram illustrating the composition of a laser ranging device provided in an embodiment of this application. Figure 10 As shown, the laser ranging device includes: a detection module 1001, a conversion module 1002, a selection module 1003, and a processing module 1004. The detection module 1001, conversion module 1002, selection module 1003, and processing module 1004 are interconnected.

[0118] The detection module 1001 is used to detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals.

[0119] The conversion module 1002 is used to convert each trigger signal into a Time Data Converter (TDC) value.

[0120] The selection module 1003 is used to select the target TDC value of the period; the target TDC value is a TDC value within the period.

[0121] The processing module 1004 is used to generate a time histogram based on the target TDC value within one or more consecutive periods, and process the time histogram to obtain ranging information.

[0122] In some embodiments, the above-described apparatus further includes a counting module 1005.

[0123] The counting module 1005 is used to count each trigger signal within a period; the target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence.

[0124] In some embodiments, n is a random number between the minimum and maximum values ​​in the counting order.

[0125] In some embodiments, the above-described apparatus further includes a determining module 1006. The determining module 1006 is configured to determine a global random number for the period; the global random number is a random number between 1 and a preset parameter; the preset parameter is used to indicate the maximum count value of the trigger signal for the entire period.

[0126] The determination module 1006 is also used to determine n based on the counting order, preset parameters, and a global random number.

[0127] In some embodiments, the determining module 1006 is specifically used to multiply the ratio of the maximum value of the counting order to a preset parameter and a global random number as n.

[0128] In some embodiments, the counting module 1005 is further configured to count the periods.

[0129] n is the value of the counting order of the trigger signal or the value of the counting order of the period, provided that the counting order of the trigger signal is equal to the counting order of the period.

[0130] In some embodiments, the determining module 1006 is further configured to determine the maximum value as n and reset the count of the period if the maximum value of the counting sequence of the trigger signal is less than the counting sequence of the period.

[0131] This application also provides a lidar system, which includes: a laser pulse emitter (equivalent to the above-mentioned...). Figure 2 Laser pulse emission module (equivalent to the above), laser pulse detector (equivalent to the above) Figure 2 The detection module and processor (equivalent to the above) Figure 2 (Chinese random sampling module and data processing module).

[0132] A laser pulse transmitter is used to send laser pulse signals.

[0133] A laser pulse detector is used to detect the echo signal of a laser pulse signal within a period of time, and obtain multiple trigger signals.

[0134] The processor is used to convert each trigger signal into a Time Data Converter (TDC) value; select a target TDC value for a period; the target TDC value is a TDC value within a period; generate a time histogram based on the target TDC values ​​within one or more consecutive periods; and process the time histogram to obtain ranging information.

[0135] In some embodiments, the laser pulse detector includes a SPAD. The SPAD is used to detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals.

[0136] In the case of implementing the functions of the integrated modules described above in hardware, this application embodiment provides a schematic diagram of the composition of an electronic device, which may be the aforementioned laser ranging device. For example... Figure 11 As shown, the electronic device 1100 includes: a processor 1102, a communication interface 1103, and a bus 1104. Optionally, the electronic device may also include a memory 1101.

[0137] Processor 1102 may implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 1102 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 1102 may also be a combination that implements computing functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0138] Communication interface 1103 is used to connect with other devices via a communication network. This communication network can be Ethernet, wireless access network, wireless local area network (WLAN), etc.

[0139] The memory 1101 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0140] As one possible implementation, the memory 1101 can exist independently of the processor 1102. The memory 1101 can be connected to the processor 1102 via the bus 1104 and is used to store instructions or program code. When the processor 1102 calls and executes the instructions or program code stored in the memory 1101, it can implement the laser ranging method provided in the embodiments of this application.

[0141] In another possible implementation, the memory 1101 can also be integrated with the processor 1102.

[0142] Bus 1104 can be an extended industry standard architecture (EISA) bus, etc. Bus 1104 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0143] Through the above description of the implementation methods, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the laser rangefinder can be divided into different functional modules to complete all or part of the functions described above.

[0144] This application also provides a computer-readable storage medium. All or part of the processes in the above method embodiments can be executed by computer instructions instructing related hardware. This program can be stored in the aforementioned computer-readable storage medium, and when executed, it can include the processes of the above method embodiments. The computer-readable storage medium can be any of the foregoing embodiments or memory. The aforementioned computer-readable storage medium can also be an external storage device for the laser ranging device, such as a plug-in hard drive, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the laser ranging device. Further, the aforementioned computer-readable storage medium can include both internal storage units of the laser ranging device and external storage devices. The aforementioned computer-readable storage medium is used to store the aforementioned computer program and other programs and data required by the laser ranging device. The aforementioned computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0145] This application also provides a computer program product comprising a computer program that, when run on a computer, causes the computer to execute any of the laser ranging methods provided in the above embodiments.

[0146] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0147] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

[0148] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A laser ranging method, characterized in that, The method includes: Within the period, the echo signal of the laser pulse signal is detected to obtain multiple trigger signals; Each of the trigger signals is converted into a Time Data Converter (TDC) value; Count each of the trigger signals within the said period; count the said period; Select the target TDC value of the period; the target TDC value is a TDC value within the period; the target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence; where n is the value of the counting sequence of the trigger signal or the value of the counting sequence of the period when the counting sequence of the trigger signal is equal to the counting sequence of the period. Based on the target TDC value within one or more consecutive periods, a time histogram is generated, and the time histogram is processed to obtain ranging information.

2. The method according to claim 1, characterized in that, The n is a random number between the minimum and maximum values ​​of the counting order.

3. The method according to claim 1, characterized in that, The method further includes: determining a global random number for the period; the global random number is a random number between 1 and a preset parameter; the preset parameter is used to indicate the maximum count value of the trigger signal for all periods; The n is determined based on the counting order, the preset parameters, and the global random number.

4. The method according to claim 3, characterized in that, Determining n based on the counting order, the preset parameters, and the global random number includes: The product of the ratio of the maximum value of the counting order to the preset parameter and the global random number is taken as n.

5. The method according to claim 1, characterized in that, The method further includes: If the maximum value of the counting sequence of the trigger signal is less than the counting sequence of the period, the maximum value is determined to be n, and the counting of the period is reset.

6. A laser ranging device, characterized in that, The device includes: a detection module, a conversion module, a selection module, and a processing module; the device also includes: a counting module. The detection module is used to detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals; The conversion module is used to convert each of the trigger signals into a Time Data Converter (TDC) value; The counting module is used to count each of the trigger signals within the period; and to count the period. The selection module is used to select a target TDC value for the period; the target TDC value is a TDC value within the period; the target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence; where n is the value of the counting sequence of the trigger signal or the value of the counting sequence of the period when the counting sequence of the trigger signal is equal to the counting sequence of the period. The processing module is used to generate a time histogram based on the target TDC value within one or more consecutive periods, and process the time histogram to obtain ranging information.

7. The apparatus according to claim 6, characterized in that, The device further includes: a determining module; The n is a random number between the minimum and maximum values ​​of the counting order; The determining module is used to determine a global random number for the period; the global random number is a random number between 1 and a preset parameter; the preset parameter is used to indicate the maximum count value of the trigger signal for all periods; The determining module is further configured to determine n based on the counting order, the preset parameters, and the global random number; The determining module is specifically used to multiply the ratio of the maximum value of the counting order to the preset parameter and the global random number as n; The determining module is further configured to, when the maximum value of the counting sequence of the trigger signal is less than the counting sequence of the period, determine the maximum value as n and reset the counting of the period.

8. A lidar system, characterized in that, The system includes: a laser pulse emitter, a laser pulse detector, and a processor; The laser pulse transmitter is used to send laser pulse signals; The laser pulse detector is used to detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals; The processor is configured to: convert each of the trigger signals into a Time Data Converter (TDC) value; count each of the trigger signals within the period; count the period; select a target TDC value for the period; the target TDC value is a TDC value within the period; the target TDC value is the TDC value obtained by converting the nth trigger signal in the counting sequence; where n is the value of the counting sequence of the trigger signals or the value of the counting sequence of the period when the counting sequence of the trigger signals is equal to the counting sequence of the period; generate a time histogram based on the target TDC values ​​in one or more consecutive periods; and process the time histogram to obtain ranging information.

9. The system according to claim 8, characterized in that, The laser pulse detector includes a single-photon avalanche diode (SPAD). The SPAD is used to detect the echo signal of the laser pulse signal within a period to obtain multiple trigger signals.

10. An electronic device, characterized in that, The electronic device includes: a processor and a memory; The memory stores instructions that the processor can execute; When the processor is configured to execute the instructions, the electronic device performs the method as described in any one of claims 1-5.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes: computer software instructions; When the computer software instructions are executed in an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-5.

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