Distance and reflectivity measurement methods, devices, storage media, and lidar

Abstract

This application discloses a method, apparatus, storage medium, and lidar for measuring distance and reflectivity. Specifically, it applies to a lidar that obtains an echo signal based on the echo light reflected from a target object. The echo signal is an electrical signal corresponding to the echo light. The application measures the echo signal based on both a distance threshold and a reflectivity threshold. The distance threshold determines the distance of the target object relative to the lidar, and the reflectivity threshold determines the reflectivity of the target object. The reflectivity threshold is higher than the distance threshold. By using different threshold values ​​to determine the distance and reflectivity of the target object, and with the reflectivity threshold being higher than the distance threshold, this application achieves higher ranging accuracy and higher reflectivity discrimination when measuring the reflectivity of the target object, thereby improving the accuracy of distance measurement and reflectivity calculations.

Description

Technical Field

[0001] This application relates to the field of laser signal processing technology, specifically to a distance and reflectivity measurement method, device, storage medium, and lidar. Background Technology

[0002] As a crucial sensor in intelligent driving systems, LiDAR has gained significant attention from major automakers. LiDAR works by emitting detection light and receiving the echo light reflected from a target object. This echo light is then converted from photoelectric to electrical signals, and the information carried by the echo signals is further analyzed to calculate distance and reflectivity, thereby enabling the perception and construction of a three-dimensional physical image.

[0003] However, in related technologies, the accuracy of distance measurement and reflectivity calculation results obtained by lidar is relatively low. Summary of the Invention

[0004] This application provides a distance and reflectivity measurement method, device, storage medium, and lidar, which can improve the accuracy of distance measurement result calculation and reflectivity calculation.

[0005] In a first aspect, embodiments of this application provide a method for measuring distance and reflectivity, including:

[0006] An echo signal is obtained based on the echo light reflected from the target object, wherein the echo signal is an electrical signal corresponding to the echo light; and

[0007] The echo signal is measured according to a distance threshold and a reflectivity threshold, wherein the distance threshold is used to determine the distance of the target object relative to the lidar, the reflectivity threshold is used to determine the reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold.

[0008] In some implementations, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold.

[0009] The step of measuring the echo signal based on a distance threshold includes:

[0010] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined; and

[0011] The distance of the target object relative to the lidar is determined based on the first candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time.

[0012] In some implementations, the ranging range of the lidar is divided into multiple second distance intervals arranged in ascending order of the upper limit value of the interval. Between any two adjacent second distance intervals, the upper limit value of one second distance interval is equal to the lower limit value of the other second distance interval. The lidar is configured with multiple reflectivity thresholds, and each second distance interval corresponds to one reflectivity threshold.

[0013] Measuring the echo signal based on a reflectivity threshold includes:

[0014] Based on the echo signal and the plurality of reflectivity thresholds, determine at least one second rising edge time corresponding to the echo signal and the echo pulse width corresponding to the second rising edge time; and

[0015] The reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0016] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. The ranging range of the lidar is also divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit value of one second distance interval is equal to the lower limit value of the other second distance interval. The lidar is configured with multiple reflectivity thresholds, and each second distance interval corresponds to one reflectivity threshold.

[0017] The step of measuring the echo signal based on a distance threshold and measuring the echo signal based on a reflectivity threshold includes:

[0018] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined;

[0019] Based on the echo signal and the plurality of reflectivity thresholds, at least one second rising edge time corresponding to the echo signal is determined; and

[0020] If the difference between the second candidate rising edge time and the first candidate rising edge time is less than a preset threshold, then the distance of the target object relative to the lidar is determined based on the first candidate rising edge time, and the reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0021] In some implementations, a first distance interval corresponds to a second distance interval, and the first distance interval is the same as the corresponding second distance interval.

[0022] In some implementations, the first preset distance interval is one of the first distance intervals, the second preset distance interval is one of the second distance intervals, and the lower limit of the second preset distance interval is greater than or equal to the upper limit of the first preset distance interval.

[0023] The distance threshold corresponding to the first preset distance interval and the reflectivity threshold corresponding to the second preset distance interval are the same threshold.

[0024] In some embodiments, prior to the steps of measuring the echo signal according to a distance threshold and measuring the echo signal according to a reflectivity threshold, the method includes:

[0025] Based on the echo signal and multiple distance thresholds, at least one rising edge time is determined;

[0026] Based on the at least one first rising edge time, a distance threshold for detecting distance and a reflectivity threshold for detecting reflectivity are determined;

[0027] The plurality of thresholds includes a distance threshold and a reflectivity threshold.

[0028] The ranging range of the lidar includes multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds and multiple reflectivity thresholds, with each first distance interval corresponding to one distance threshold and one reflectivity threshold.

[0029] Secondly, embodiments of this application also provide a laser signal processing apparatus, comprising:

[0030] A signal transceiver module is used to obtain an echo signal based on the echo light reflected from a target object, wherein the echo signal is an electrical signal corresponding to the echo light; and

[0031] A signal processing module is used to measure the echo signal according to a distance threshold and a reflectivity threshold, wherein the distance threshold is used to determine the distance of the target object relative to the lidar, the reflectivity threshold is used to determine the reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold.

[0032] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. The signal processing module is used for:

[0033] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined; and

[0034] The distance of the target object relative to the lidar is determined based on the first candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time.

[0035] In some embodiments, the ranging range of the lidar is divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit of one second distance interval is equal to the lower limit of the other. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. A signal processing module is used for:

[0036] Based on the echo signal and the plurality of reflectivity thresholds, determine at least one second rising edge time corresponding to the echo signal and the echo pulse width corresponding to the second rising edge time; and

[0037] The reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0038] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds, with each first distance interval corresponding to one distance threshold. The ranging range of the lidar is also divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit of one second distance interval is equal to the lower limit of the other. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. A signal processing module is used for:

[0039] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined;

[0040] Based on the echo signal and the plurality of reflectivity thresholds, at least one second rising edge time corresponding to the echo signal is determined; and

[0041] If the difference between the second candidate rising edge time and the first candidate rising edge time is less than a preset threshold, then the distance of the target object relative to the lidar is determined based on the first candidate rising edge time, and the reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0042] In some implementations, a first distance interval corresponds to a second distance interval, and the first distance interval is the same as the corresponding second distance interval.

[0043] In some implementations, the first preset distance interval is one of the first distance intervals, the second preset distance interval is one of the second distance intervals, the lower limit of the second preset distance interval is greater than or equal to the upper limit of the first preset distance interval, and the distance threshold corresponding to the first preset distance interval and the reflectivity threshold corresponding to the second preset distance interval are the same threshold.

[0044] In some implementations, the signal processing module is used for:

[0045] Based on the echo signal and multiple distance thresholds, at least one rising edge time is determined;

[0046] Based on the at least one first rising edge time, a distance threshold for detecting distance and a reflectivity threshold for detecting reflectivity are determined;

[0047] The plurality of thresholds includes a distance threshold and a reflectivity threshold.

[0048] The ranging range of the lidar includes multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds and multiple reflectivity thresholds, with each first distance interval corresponding to one distance threshold and one reflectivity threshold.

[0049] Thirdly, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, which, when run on a computer, causes the computer to perform the distance and reflectivity measurement method as provided in any embodiment of this application.

[0050] Fourthly, embodiments of this application also provide a lidar, including a processor and a memory, the memory having a computer program, the processor executing the distance and reflectivity measurement method as provided in any embodiment of this application by calling the computer program.

[0051] The technical solution provided in this application is applied to a lidar. This lidar obtains an echo signal based on the echo light reflected from a target object. The echo signal is an electrical signal corresponding to the echo light. The lidar measures the echo signal according to both a distance threshold and a reflectivity threshold. The distance threshold determines the distance of the target object relative to the lidar, and the reflectivity threshold determines the reflectivity of the target object. The reflectivity threshold is higher than the distance threshold. This application uses different threshold values ​​to determine the distance and reflectivity of the target object, with the reflectivity threshold being higher than the distance threshold. This results in higher ranging accuracy when measuring the distance to the target object and higher reflectivity discrimination when measuring the reflectivity of the target object, thereby improving the accuracy of the ranging and reflectivity calculations. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram illustrating the processing of echo signals from two target objects at the same distance but with different reflectivities using different threshold sizes, as provided in an embodiment of this application.

[0054] Figure 2 This is a schematic diagram of wave detection of a certain echo signal using a threshold, provided as an embodiment of this application, wherein the signal under test may contain noise signals.

[0055] Figure 3 This is a schematic diagram illustrating the processing of echo signals corresponding to multiple target objects with different reflectivities at the same distance using the same threshold, as provided in an embodiment of this application.

[0056] Figure 4 This is a schematic diagram of the first process of the distance and reflectivity measurement method provided in the embodiments of this application.

[0057] Figure 5 This is a flowchart illustrating step S220 provided in an embodiment of this application.

[0058] Figure 6 This is a schematic diagram illustrating the use of multiple thresholds to perform detection processing on multiple target objects at different distances, as provided in the embodiments of this application.

[0059] Figure 7This is a schematic diagram of the structure of the laser signal processing device provided in the embodiments of this application.

[0060] Figure 8 This is a schematic diagram of a lidar structure provided in an embodiment of this application. Detailed Implementation

[0061] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0062] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0063] As a crucial sensor in intelligent driving systems, LiDAR has gained significant attention from major automakers. LiDAR works by emitting detection light and receiving the echo light reflected from a target object. This echo light is then converted from photoelectric to electrical signals, and the information carried by the echo signals is further analyzed to calculate distance and reflectivity, thereby achieving the perception and construction of a three-dimensional physical image.

[0064] However, in related technologies, the accuracy of distance measurement and reflectivity calculation results obtained by lidar is relatively low.

[0065] The applicant's research revealed that for two target objects with different reflectivities at the same distance, the target object with higher reflectivity emits stronger echo energy, resulting in a generally higher signal amplitude after photoelectric conversion. Conversely, the target object with lower reflectivity emits weaker echoes, resulting in a generally lower signal amplitude after photoelectric conversion. After threshold detection by a Time-to-Digital Converter (TDC), the rise time and echo pulse width can be obtained from the echo signal. The rise time is used to convert the distance to the target object, and the echo pulse width is used to calculate the reflectivity. Due to the influence of the echo waveform, different threshold heights yield different results when detecting the same echo signal, and the same threshold also produces different amplitude echo signals at the same distance. Generally, all other things being equal, a higher threshold results in a later rise time and a smaller pulse width; conversely, all other things being equal, a higher echo signal amplitude results in an earlier rise time and a larger pulse width.

[0066] For details, please refer to Figure 1 In the figure, the strong echo signal and the weak echo signal represent the echo signals corresponding to two target objects with different reflectivities at the same distance. Since the distance of the target object is proportional to the flight time of the laser, Figure 1 The diagram illustrates two detection thresholds: a high threshold and a low threshold. D11, D12, D21, and D22 represent the distances calculated directly from the rising edge times of four scenarios: strong echo (low threshold), weak echo (low threshold), strong echo (high threshold), and weak echo (high threshold), respectively. W11, W12, W21, and W22 represent the corresponding echo pulse widths. The following pattern emerges from the diagram: a lower detection threshold results in a smaller change in ranging accuracy with echo signal strength, but correspondingly, the echo pulse width also changes less with signal strength, leading to poorer reflectivity discrimination. Conversely, a higher detection threshold results in a larger ranging error, but better reflectivity discrimination.

[0067] When the detection threshold is too low, background light, crosstalk, and other noise may be detected, affecting the detection of the target object. Please refer to [reference needed]. Figure 2 , Figure 2 This diagram illustrates the potential noise signals that may exist when using a threshold to detect a certain echo signal, as provided in an embodiment of this application. As can be seen from the diagram, the detection threshold used for ranging is not necessarily better the lower it is, but rather the lower the better, without affecting the echo signal detection rate. Generally, it should be higher than the noise estimate.

[0068] Please refer to this again. Figure 3 , Figure 3The diagram illustrates an example of using the same detection threshold to detect the echo signals of multiple target objects with different reflectivities at the same distance. As shown, when using a higher threshold to achieve better reflectivity discrimination, it may be impossible to detect target objects with lower reflectivity at the same distance. That is, the requirements for detection threshold height differ between ranging and reflectivity. The optimal threshold height ranges for ranging and reflectivity within the same distance segment do not overlap or have very little overlap, making it difficult to achieve optimal ranging accuracy and reflectivity discrimination simultaneously using the same threshold.

[0069] Therefore, this application provides a distance and reflectivity measurement method that separates the range and reflectivity thresholds, uses multiple thresholds for detection, employs a range threshold for range measurement, and uses a reflectivity threshold for reflectivity measurement, with the reflectivity threshold being greater than the range threshold to achieve optimal range and reflectivity differentiation. The execution entity of this distance and reflectivity measurement method can be the laser signal processing device provided in this application, an electronic device integrating the laser signal processing device, or a lidar; wherein the laser signal processing device can be implemented in hardware or software.

[0070] Please see Figure 4 , Figure 4 This is a schematic diagram of a first step in the distance and reflectivity measurement method provided in this application embodiment. The distance and reflectivity measurement method provided in this application embodiment is applied to lidar, and the specific flow of this distance and reflectivity measurement method is as follows:

[0071] S110. Obtain the echo signal based on the echo light reflected from the target object.

[0072] It should be noted that the "target object" mentioned in this application is the object detected by the lidar, which includes, but is not limited to: vehicles, pedestrians, buildings, vegetation, and the ground; the "echo light" mentioned in this application is formed by the reflection of the detection light emitted by the lidar at the target object, and the echo light is the laser light emitted from the target object towards the lidar; the "echo signal" mentioned in this application is the electrical signal corresponding to the echo light, which can be obtained by photodetector in the form of photoelectric conversion.

[0073] In this embodiment, the lidar acquires an echo signal by emitting a laser beam toward a target object and receiving the echo light reflected back from the target object. In some embodiments, the lidar includes a laser and a detector. The laser generates a probe light to detect the target object. When the probe light encounters the target object, part of the light is reflected by the target object, forming an echo light that travels toward the lidar. The detector receives the echo light and performs photoelectric conversion to obtain the aforementioned echo signal.

[0074] In one example, consider an autonomous vehicle:

[0075] Autonomous vehicles are typically equipped with LiDAR (Light Detection and Ranging) to perceive their surroundings. When LiDAR emits detection light from a laser towards nearby vehicles, pedestrians, obstacles, and other targets, these targets reflect the light, creating echoes. The LiDAR then receives these echoes using a detector and converts them into electrical signals—the echo signals—which are used to further perceive the vehicle's environment. For example, the echo signals can be used to calculate information such as the distance, speed, and reflectivity of target objects. Based on this information, the autonomous vehicle can plan its path in real time, avoid collisions, and ensure driving safety.

[0076] S120. Measure the echo signal according to the distance threshold and the reflectivity threshold. The reflectivity threshold is higher than the distance threshold.

[0077] Among these, the threshold corresponds to a signal strength threshold; only echo signals exceeding this threshold are considered valid. The distance threshold is the ranging signal strength threshold used to determine the distance of the target object relative to the lidar. The reflectivity threshold is the reflectivity signal strength threshold used to determine the reflectivity of the target object.

[0078] The "thresholds" mentioned in this application include both distance and reflectivity thresholds, both of which can be configured via a TDC (Transmitter Controlled Detector). A TDC is a circuit that converts time-domain signals into digital signals. In applications such as radar or ultrasonic ranging, TDCs are commonly used to measure the time interval between the transmitted signal and the echo signal, thereby calculating the distance to an obstacle. It should be noted that after the echo signal is detected by the TDC, the rise time and echo pulse width can be obtained. The rise time is used to calculate the distance between the target object and the lidar, and the echo pulse width is used to calculate the reflectivity of the target object. It should be further clarified that the "rise time" mentioned in this application refers to the moment the signal crosses the threshold. Since the echo signal is an analog signal, the rise time refers to the moment the signal waveform rises to the threshold. After the TDC acquires the signal and converts it into a digital signal, the portion of the signal below the threshold is set to zero, and the portion above the threshold is set to one. The rise time is the moment the digital signal jumps from 0 to 1. During the TDC detection process, the rise time of the echo signal is usually detected to determine the signal arrival time, which can be used to calculate the distance between the lidar and the target object. Similarly, the "falling edge time," which will be introduced below, refers to the moment when the signal waveform falls to the threshold. Since the echo signal is an analog signal, the falling edge time refers to the moment when the signal waveform falls to the threshold. After the TDC acquires the signal and converts it into a digital signal, the portion of the signal below the threshold is set to zero, and the portion above the threshold is set to one. The falling edge time is the moment when the digital signal jumps from 1 to 0. During TDC detection, the falling edge time of the echo signal is usually detected to determine the echo pulse width based on the rising edge time and the falling edge time. The echo pulse width is the time interval between the rising edge time and the falling edge time of the echo signal, which is the duration of the echo signal detected by the TDC. The echo pulse width can provide information about certain characteristics of the target object, such as reflectivity.

[0079] In this embodiment, two different detection thresholds are configured, namely the distance threshold and the reflectivity threshold, and the reflectivity threshold is higher than the distance threshold. The distance threshold is used to determine the distance of the target object relative to the lidar, and the reflectivity threshold is used to measure the reflectivity of the target object.

[0080] In practice, this application is not limited by the execution order of the described steps. Without causing conflicts, some steps may be performed in other orders or simultaneously.

[0081] As can be seen from the above, the distance and reflectivity measurement method provided in this application is applied to a lidar. The lidar obtains an echo signal based on the echo light reflected from a target object. The echo signal is an electrical signal corresponding to the echo light. The method measures the echo signal based on both a distance threshold and a reflectivity threshold. The distance threshold is used to determine the distance of the target object relative to the lidar, and the reflectivity threshold is used to determine the reflectivity of the target object. The reflectivity threshold is higher than the distance threshold. This application uses different threshold values ​​to determine the distance and reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold. This results in higher ranging accuracy when measuring the distance to the target object and higher reflectivity discrimination when measuring the reflectivity of the target object, thereby improving the accuracy of the distance measurement result calculation and reflectivity calculation.

[0082] Based on the methods described in the preceding embodiments, the following examples will provide further detailed explanations.

[0083] This distance and reflectivity measurement method is applied to lidar, including:

[0084] S210. Obtain the echo signal based on the echo light reflected from the target object.

[0085] Step S210 is the same as step S110, and will not be repeated here.

[0086] S220. Measure the echo signal according to the distance threshold and the reflectivity threshold. The reflectivity threshold is higher than the distance threshold.

[0087] The applicant's research revealed that, because the intensity of the echo signal is inversely proportional to the square of the distance to the target object, the dynamic range of the signal across the entire ranging range is very large. The intensity of crosstalk noise and other signals caused by near-range targets may be higher than the actual echo intensity at a distance. Furthermore, the optimal reflectivity threshold at near range fails to detect weak echoes at long range, making reflectivity calculation impossible. Therefore, the applicant further implemented a system where different thresholds are configured for different distance segments, and the results are fused to ensure that the ranging and reflectivity thresholds for each segment are within their optimal operating range. Please refer to [link to relevant documentation]. Figure 5 The diagram shows a flowchart of step S220, which specifically includes steps S221 and S222.

[0088] S221. Based on the echo signal and multiple distance thresholds, determine at least one first rising edge time corresponding to the echo signal, and determine the distance of the target object relative to the lidar based on the first candidate rising edge time; wherein, if the first distance interval corresponding to the distance determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time.

[0089] It should be noted that the applicant has set different distance thresholds and reflectivity thresholds for different distance intervals within the ranging range of the lidar. The distance threshold and reflectivity threshold for each distance interval can be set by those skilled in the art based on empirical values ​​summarized from actual detection scenarios, and will not be elaborated here.

[0090] In this embodiment, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. In some embodiments, in accordance with the lidar equation, the higher the median or upper limit value of the first distance interval, the lower the distance threshold corresponding to it.

[0091] Specifically, when measuring the echo signal based on a range threshold, the lidar can determine at least one first rising edge moment corresponding to the echo signal based on the echo signal and multiple range thresholds. If the first range interval corresponding to the first rising edge moment determined by the range threshold is the same as the first range interval corresponding to the same range threshold, then the first rising edge moment is a first candidate rising edge moment. Then, the distance of the target object relative to the lidar is determined based on the first candidate rising edge moment.

[0092] It should be noted that in actual echo signal detection, each threshold (e.g., each distance threshold) operates simultaneously. Therefore, each threshold may detect a signal and obtain the corresponding rise time, fall time, and corresponding echo pulse width. For example, in some embodiments, please refer to... Figure 6In the figure, distance is used as the horizontal axis and signal strength / amplitude as the vertical axis. The ranging range of the lidar is divided into multiple first distance intervals, which are arranged in ascending order of distance: the first interval (0, a), the second interval (a, c), and the third interval (c, e). Multiple ranging thresholds are threshold 3, threshold 2, and threshold 1. Threshold 3 corresponds to the first interval, threshold 2 to the second interval, and threshold 1 to the third interval. Each threshold is higher than the noise estimate within its corresponding first distance interval. The detection pattern is located within the first interval. Taking the signal as an example, all three ranging thresholds (threshold 3 to threshold 1) will detect the signal and obtain the corresponding rise time, fall time, and echo pulse width. The rise time obtained from the three thresholds can be used to determine that the target object corresponding to the echo signal is located in the first interval. However, it should be noted that since the echo signal intensity decreases quadratically with distance, the threshold values ​​corresponding to the first, second, and third intervals gradually decrease to allow echo signals from more distant locations to be detected. Threshold 2 and threshold 1 for the second and third intervals are significantly lower than threshold 1; in other words, the first interval... The noise within the interval may be higher than the threshold of the second or third interval. Therefore, the signal detected based on threshold 2 and threshold 1 may include echo signals and / or noise signals. If the rising edge time, falling edge time, and echo pulse width are determined directly based on threshold 2 and threshold 1, the information of the echo signal cannot be accurately represented. In contrast, threshold 3 is higher than the noise estimate within the interval, so the determined signal is the correct echo signal. Based on this, in step S221, the first distance interval corresponding to the first rising edge time determined by the distance threshold is located, and the first distance corresponding to the same distance threshold is... When the intervals are the same (i.e., the first candidate rising edge time), the signal can be identified as an echo signal, and the distance to the target object can be determined based on the first candidate rising edge time. The method for detecting signals located in the second and third intervals is basically the same as that for the first interval, and will not be repeated here. It should be noted that in this application, "the distance corresponding to the first rising edge time" means half of the laser's optical path within the time interval between the first rising edge time and the emission of the probe light (or the generation of the reference signal), that is, the calculated distance of the target object relative to the lidar, and not the complete optical path of the laser.

[0093] S222. Based on the echo signal and multiple reflectivity thresholds, determine at least one second rising edge time corresponding to the echo signal and the echo pulse width corresponding to the second rising edge time, and determine the reflectivity of the target object based on the echo pulse width corresponding to the second candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0094] In this embodiment, the ranging range of the lidar is divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit of one second distance interval is equal to the lower limit of the other. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. In some embodiments, in accordance with the lidar equation, the higher the median or upper limit value of the second distance interval, the lower the reflectivity threshold corresponding to it.

[0095] Specifically, when measuring echo signals based on reflectivity thresholds, the lidar can first determine at least one second rising edge time and the corresponding echo pulse width based on the echo signal and multiple reflectivity thresholds. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is a second candidate rising edge time. Then, the reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time.

[0096] It should be noted that in actual echo signal detection, each threshold (e.g., each reflectivity threshold) operates simultaneously. Therefore, each threshold may detect a signal and obtain the corresponding rise time, fall time, and corresponding echo pulse width. For example, in some embodiments, please refer to... Figure 6In the diagram, distance is the horizontal axis and signal strength / amplitude is the vertical axis. The ranging range of the lidar is divided into multiple second distance intervals, which are the fourth, fifth, and sixth intervals arranged in ascending order of distance. The fourth interval is [0, b], the fifth interval is (b, d], and the sixth interval is (d, e]. Multiple ranging thresholds are threshold 4, threshold 3, and threshold 2. Threshold 4 corresponds to the fourth interval, threshold 3 to the fifth interval, and threshold 2 to the sixth interval. Each threshold is higher than the noise estimate within its corresponding second distance interval. Taking the signal located in the fourth interval as an example, all three ranging thresholds (threshold 4 to threshold 2) will detect the signal and obtain the corresponding rise time, fall time, and echo pulse width. The rise time obtained from the three thresholds can be used to determine that the target object corresponding to the echo signal is located in the fourth interval. However, it should be noted that since the echo signal strength decreases quadratically with distance, the threshold values ​​for the fourth, fifth, and sixth intervals gradually increase. The thresholds gradually decrease, with thresholds 3 and 2 corresponding to the fifth and sixth intervals being significantly lower than threshold 4. In other words, the noise in the fourth interval may be higher than that in the fifth interval or its threshold. Therefore, the signals detected based on thresholds 3 and 2 may include echo signals and / or noise signals. If the rising edge time, falling edge time, and echo pulse width are determined directly based on thresholds 3 and 2, they cannot accurately represent the information of the echo signal. In contrast, threshold 4 is higher than the noise estimate in that interval, so the determined signal is the correct echo signal. Based on this, in step S222, when the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold (i.e., the second candidate rising edge time), the signal can be determined as an echo signal, and the reflectivity of the target object can be determined based on the echo pulse width corresponding to the second candidate rising edge time. The method for detecting signals located in the fifth and sixth intervals is basically the same as that for the fourth interval, and will not be repeated here.

[0097] The above describes the methods of distance measurement and reflectivity measurement relatively independently. Generally, accurate information can be obtained by obtaining distance and reflectivity in isolation based on the above methods. However, in special cases, the distance obtained based on step S221 and the reflectivity obtained based on step S222 may not correspond to the same signal. Therefore, before using the information (rise edge time, fall edge time, and pulse width information, etc.) determined by the distance threshold and reflectivity threshold, it is necessary to determine whether the signals measured by the distance threshold and reflectivity threshold are the same signal. The specific implementation method is as follows.

[0098] In some implementations, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. Similarly, the ranging range of the lidar can also be divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit value of one second distance interval is equal to the lower limit value of the other. The lidar is configured with multiple reflectivity thresholds, and each second distance interval corresponds to one reflectivity threshold.

[0099] Similar to step S221 above, when the lidar measures the echo signal according to a distance threshold, at least one first rising edge time corresponding to the echo signal can be determined based on the echo signal and multiple distance thresholds. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is a first candidate rising edge time. It should be noted that there may be multiple first candidate rising edge times. Similarly to step S222 above, when measuring the echo signal according to a reflectivity threshold, at least one second rising edge time corresponding to the echo signal can be determined based on the echo signal and multiple reflectivity thresholds. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is a second candidate rising edge time. It should be noted that there may be multiple first candidate rising edge times. Next, the relationship between the first candidate rising edge time and the second candidate rising edge time is determined. Specifically, if the time interval between the second candidate rising edge time and the first candidate rising edge time is less than a preset threshold, then the confidence level of the second candidate rising edge time and the first candidate rising edge time corresponding to the same signal is very high. The distance of the target object relative to the lidar can be determined based on the first candidate rising edge time, and the reflectivity of the target object can be determined based on the echo pulse width corresponding to the second candidate rising edge time. The "time interval" between the second candidate rising edge time and the first candidate rising edge time can be determined by the absolute value of the difference between the second candidate rising edge time and the first candidate rising edge time. The preset threshold can be set by those skilled in the art based on experience. For example, twice the time corresponding to the distance resolution of the lidar (the round-trip travel of the laser needs to be considered in the signal time domain) can be determined as the preset threshold. When there is only one first candidate rising edge and one second candidate rising edge, the first candidate rising edge and the second candidate rising edge can be directly compared. When there are multiple first candidate rising edges and multiple second candidate rising edges, each first candidate rising edge can be compared with multiple second candidate rising edges. A pair of first candidate rising edges and second candidate rising edges with a time interval less than a preset threshold are identified as corresponding to the same echo signal. At this time, the distance to the target object can be determined based on the first candidate rising edge, and the reflectivity of the target object can be determined based on the echo pulse width corresponding to the second candidate rising edge.

[0100] In some implementations, the first distance interval corresponds one-to-one with the second distance interval; for example, please refer to [link to relevant documentation]. Figure 6The ranging range of the lidar includes three first distance intervals and three second distance intervals. Each first distance interval has a corresponding second distance interval. The corresponding first and second distance intervals largely overlap, with only a small portion not overlapping. Preferably, the first distance interval can be the same as the corresponding second distance interval, which helps to simplify the relationship between the threshold and the distance, and simplifies the allocation of the threshold.

[0101] Considering that the thresholds are configured by a TDC (Transmission Control Center), and each threshold configuration requires one TDC, configuring a separate distance threshold for each first distance interval and a separate reflectivity threshold for each second distance interval would result in a total number of thresholds equal to the sum of the number of first and second distance intervals. This would consume a large number of TDCs, increasing the hardware cost of the lidar. Therefore, in some embodiments of this application, while ensuring ranging and reflectivity measurement performance, thresholds can be reused to reduce resource consumption. Specifically, for example, a first preset distance interval can be one of all first distance intervals, and a second preset distance interval can be one of all second distance intervals. The lower limit of the second preset distance interval is greater than or equal to the upper limit of the first preset distance interval, meaning the second preset distance interval is a distance interval with a larger distance than the first preset distance interval. The distance threshold corresponding to the first preset distance interval and the reflectivity threshold corresponding to the second preset distance interval can be the same threshold.

[0102] Next, combined Figure 6 The above implementation method is described. The range thresholds configured by the lidar through multiple TDCs include threshold 3 corresponding to the first interval, threshold 2 corresponding to the second interval, and threshold 1 corresponding to the third interval. The reflectivity thresholds configured by the multiple TDCs include threshold 4 corresponding to the fourth interval, threshold 3 corresponding to the fifth interval, and threshold 2 corresponding to the sixth interval. That is, the range threshold corresponding to the first interval (first preset range interval) and the reflectivity threshold corresponding to the fifth interval (second preset range interval) are the same thresholds and can be configured through the same TDC; the range threshold corresponding to the second interval (first preset range interval) and the reflectivity threshold corresponding to the sixth interval (second preset range interval) are the same thresholds and can be configured through the same TDC. The above configuration enables the lidar to achieve the functions of three range thresholds and three reflectivity thresholds with only four TDCs, which helps to reduce hardware consumption, hardware costs, and system complexity.

[0103] It is worth mentioning that, due to some thresholds (such as...) Figure 6The threshold 3 and threshold 2 shown are multiplexed to have both distance and reflectivity threshold functions. Therefore, when detecting signals, it is necessary to determine whether this threshold should be used as a distance threshold or a reflectivity threshold. Since the first and second distance intervals mentioned above are both based on distance division, the multiplexed threshold can also be distinguished as either a distance threshold or a reflectivity threshold based on the distance interval corresponding to the determined rising edge time. Taking the signal detection by threshold 3 as an example, if the distance corresponding to the rising edge time determined by threshold 3 is in the first interval mentioned above, then threshold 3 should be used as a distance threshold. If the distance corresponding to the rising edge time determined by threshold 3 is in the fifth interval mentioned above, then threshold 3 should be used as a reflectivity threshold. The determination method for threshold 2 as a distance threshold and a reflectivity threshold is similar and will not be elaborated here.

[0104] It should be understood that although the above embodiments all first determine the first candidate rising edge time and the second candidate rising edge time independently through each threshold (distance threshold and reflectivity threshold), and then combine the first candidate rising edge time, the second candidate rising edge time and the corresponding echo pulse width of the second candidate rising edge time to further obtain distance information and reflectivity information, this application is not limited to this; in other ways of this application, the distance interval corresponding to the distance of the echo signal can be determined first based on the echo signal and each distance threshold, and then the corresponding distance threshold and reflectivity threshold can be determined based on the distance interval, and the first candidate rising edge time can be determined according to the distance threshold, thereby determining the distance of the target object relative to the lidar, and the second candidate rising edge time can be determined based on the reflectivity threshold, thereby determining the reflectivity of the target object.

[0105] Specifically, the ranging range of the lidar can still include multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds and multiple reflectivity thresholds, with each first distance interval corresponding to one distance threshold and one reflectivity threshold. When detecting echo signals, at least one first rising edge moment can be determined based on the echo signal and each distance threshold. Then, based on this at least one first rising edge moment, a distance threshold for detecting distance and a reflectivity threshold for detecting reflectivity are determined. For example, a corresponding distance value can be determined based on each first rising edge moment, a desired distance value can be determined based on the determined distance values, and based on the distance interval in which the desired distance value is located, and the correspondence between the aforementioned distance interval and the corresponding distance threshold and reflectivity threshold, the distance threshold and reflectivity threshold corresponding to that distance interval are further determined. The desired distance value can be obtained through an arithmetic average or a weighted average. Then, the echo signal is detected using a defined distance threshold and reflectivity threshold to obtain the corresponding first candidate rising edge time, second candidate rising edge time, and echo pulse width corresponding to the second candidate rising edge time. Based on the above information, the distance and reflectivity of the target object are determined.

[0106] As can be seen from the above, the distance and reflectivity measurement method proposed in this application determines the distance and reflectivity of a target object by using different threshold values, with the reflectivity threshold being higher than the distance threshold. This results in higher distance measurement accuracy and higher reflectivity discrimination when measuring the reflectivity of the target object. Furthermore, the method further determines whether the rising edge times detected by the distance threshold and the reflectivity threshold are the same signal based on the time interval between the rising edge times detected by the distance threshold and the reflectivity threshold, i.e., the aforementioned preset threshold. This enables accurate distance and reflectivity measurement of a certain object, further improving the accuracy of distance measurement and reflectivity calculation for the target object.

[0107] In one embodiment, a laser signal processing apparatus is also provided. See also... Figure 7 , Figure 7 This is a schematic diagram of the structure of a laser signal processing device 300 provided in an embodiment of this application. The laser signal processing device 300 is applied to a lidar system and includes a signal transceiver module 301 and a signal processing module 302, as follows:

[0108] The signal transceiver module 301 is used to obtain an echo signal based on the echo light reflected from the target object, wherein the echo signal is an electrical signal corresponding to the echo light; and

[0109] The signal processing module 302 is used to measure the echo signal according to a distance threshold and a reflectivity threshold, wherein the distance threshold is used to determine the distance of the target object relative to the lidar, the reflectivity threshold is used to determine the reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold.

[0110] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. The signal processing module 302 is used for:

[0111] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined; and

[0112] The distance of the target object relative to the lidar is determined based on the first candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time.

[0113] In some embodiments, the ranging range of the lidar is divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit of one second distance interval is equal to the lower limit of the other. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. The signal processing module 302 is used for:

[0114] Based on the echo signal and the plurality of reflectivity thresholds, determine at least one second rising edge time corresponding to the echo signal and the echo pulse width corresponding to the second rising edge time; and

[0115] The reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0116] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds, with each first distance interval corresponding to one distance threshold. The ranging range of the lidar is also divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit of one second distance interval is equal to the lower limit of the other. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. The signal processing module 302 is used for:

[0117] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined;

[0118] Based on the echo signal and the plurality of reflectivity thresholds, at least one second rising edge time corresponding to the echo signal is determined; and

[0119] If the difference between the second candidate rising edge time and the first candidate rising edge time is less than a preset threshold, then the distance of the target object relative to the lidar is determined based on the first candidate rising edge time, and the reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0120] In some implementations, a first distance interval corresponds to a second distance interval, and the first distance interval is the same as the corresponding second distance interval.

[0121] In some implementations, the first preset distance interval is one of the first distance intervals, the second preset distance interval is one of the second distance intervals, the lower limit of the second preset distance interval is greater than or equal to the upper limit of the first preset distance interval, and the distance threshold corresponding to the first preset distance interval and the reflectivity threshold corresponding to the second preset distance interval are the same threshold.

[0122] In some implementations, the signal processing module 302 is used for:

[0123] Based on the echo signal and multiple distance thresholds, at least one rising edge time is determined;

[0124] Based on the at least one first rising edge time, a distance threshold for detecting distance and a reflectivity threshold for detecting reflectivity are determined;

[0125] The plurality of thresholds includes a distance threshold and a reflectivity threshold.

[0126] The ranging range of the lidar includes multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds and multiple reflectivity thresholds, with each first distance interval corresponding to one distance threshold and one reflectivity threshold.

[0127] It should be noted that the laser signal processing device provided in this application embodiment and the distance and reflectivity measurement method in the above embodiment belong to the same concept. The laser signal processing device can realize any of the methods provided in the distance and reflectivity measurement method embodiment. For details of the specific implementation process, please refer to the distance and reflectivity measurement method embodiment, which will not be repeated here.

[0128] Furthermore, to better implement the distance and reflectivity measurement method in the embodiments of this application, this application also provides a lidar 400 based on the distance and reflectivity measurement method. Please refer to [link to relevant documentation]. Figure 8 , Figure 8 This is a schematic diagram of a lidar 400 provided in an embodiment of this application. The lidar 400 may include a transmitting unit 401, a receiving unit 402, a memory 403, and a processor 404. The transmitting unit 401, the receiving unit 402, the memory 403, and the processor 404 are electrically connected.

[0129] The transmitting unit 401 is used to emit detection laser light towards the target object. Specifically, the transmitting unit 401 of the lidar 400 is the signal source of the lidar 400, directly affecting the performance of the lidar 400 sensor. The main function of the transmitting unit 401 is to emit a laser signal of a certain power at a specific wavelength and waveform through an optical transmitter. These laser signals are reflected back after encountering the target object, providing information to the receiving unit 402. The transmitting unit 401 generally consists of an excitation source, a laser, a laser modulator, a beam controller, and an optical generator.

[0130] The receiving unit 402 is used to receive the echo light reflected from the target object. Specifically, the receiving unit 402 of the lidar 400 is responsible for receiving the laser signal reflected back from the target object. Its main function is to perform photoelectric conversion, that is, to convert the received optical signal into an electrical signal for subsequent processing.

[0131] The memory 403 can be used to store computer programs and data. The computer program stored in the memory 403 contains instructions that can be executed in the processor 404. The computer program can be composed of various functional modules. The processor 404 executes various functional applications and data processing by calling the computer program stored in the memory 403. The memory 403 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for at least one function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created based on the use of the lidar 400 (such as audio data, video data, etc.). In addition, the memory 403 may include a high-speed random access memory 403, and may also include non-volatile memory 403, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device 403, flash memory device, or other volatile solid-state memory 403.

[0132] The processor 404 is the control center of the lidar 400. It connects all parts of the lidar 400 via various interfaces and lines. By running or calling computer programs stored in the memory 403, and by calling data stored in the memory 403, it executes various functions and processes data of the lidar 400, thereby providing overall monitoring of the lidar 400. The processor 404 can be a central processing unit (CPU), or other general-purpose processors 404, digital signal processors 404 (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor 404 can be a microprocessor 404, or any conventional processor 404.

[0133] In this embodiment, the processor 404 in the lidar 400 loads the instructions corresponding to the processes of one or more computer programs into the memory 403 according to the following steps, and the processor 404 runs the computer programs stored in the memory 403 to realize various functions:

[0134] An echo signal is obtained based on the echo light reflected from the target object, wherein the echo signal is an electrical signal corresponding to the echo light; and

[0135] The echo signal is measured according to a distance threshold and a reflectivity threshold, wherein the distance threshold is used to determine the distance of the target object relative to the lidar, the reflectivity threshold is used to determine the reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold.

[0136] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. When the processor 404 executes the measurement of the echo signal based on the distance thresholds, it can perform the following: determining at least one first rising edge time corresponding to the echo signal based on the echo signal and the multiple distance thresholds; and

[0137] The distance of the target object relative to the lidar is determined based on the first candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time. In some embodiments, the ranging range of the lidar is divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit value of one second distance interval is equal to the lower limit value of the other second distance interval. The lidar is configured with multiple reflectivity thresholds, and each second distance interval corresponds to one reflectivity threshold. When the processor 404 executes the measurement of the echo signal based on the reflectivity threshold, it can perform the following:

[0138] Based on the echo signal and the plurality of reflectivity thresholds, determine at least one second rising edge time corresponding to the echo signal and the echo pulse width corresponding to the second rising edge time; and

[0139] The reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

[0140] In some embodiments, the ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit of one first distance interval is equal to the lower limit of the other. The lidar is configured with multiple distance thresholds, with each first distance interval corresponding to one distance threshold. The ranging range of the lidar is also divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit of one second distance interval is equal to the lower limit of the other. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. The processor 404 executes the measurement of the echo signal according to the distance thresholds. When measuring the echo signal according to the reflectivity thresholds, it can execute:

[0141] Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined;

[0142] Based on the echo signal and the plurality of reflectivity thresholds, at least one second rising edge time corresponding to the echo signal is determined; and

[0143] If the difference between the second candidate rising edge time and the first candidate rising edge time is less than a preset threshold, then the distance of the target object relative to the lidar is determined based on the first candidate rising edge time, and the reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. Specifically, if the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time. Similarly, if the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time. In some embodiments, a first distance interval corresponds to a second distance interval, and the first distance interval and the corresponding second distance interval are the same.

[0144] In some implementations, the first preset distance interval is one of the first distance intervals, the second preset distance interval is one of the second distance intervals, the lower limit of the second preset distance interval is greater than or equal to the upper limit of the first preset distance interval, and the distance threshold corresponding to the first preset distance interval and the reflectivity threshold corresponding to the second preset distance interval are the same threshold.

[0145] In some embodiments, before performing the steps of measuring the echo signal according to a distance threshold and measuring the echo signal according to a reflectivity threshold, the processor 404 may also perform:

[0146] Based on the echo signal and multiple distance thresholds, at least one rising edge time is determined;

[0147] Based on the at least one first rising edge time, a distance threshold for detecting distance and a reflectivity threshold for detecting reflectivity are determined;

[0148] The plurality of thresholds includes a distance threshold and a reflectivity threshold.

[0149] The ranging range of the lidar includes multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds and multiple reflectivity thresholds, with each first distance interval corresponding to one distance threshold and one reflectivity threshold.

[0150] This application also provides a computer-readable storage medium storing a computer program. When the computer program is run on a computer, the computer executes the distance and reflectivity measurement method described in any of the above embodiments.

[0151] It should be noted that those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, which may include, but is not limited to, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0152] Furthermore, the terms "first," "second," and "third," etc., used in this application are used to distinguish different objects, not to describe a specific order. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the listed steps or modules, but some embodiments may also include steps or modules not listed, or some embodiments may include other steps or modules inherent to these processes, methods, products, or devices.

[0153] The distance and reflectivity measurement method, apparatus, storage medium, and lidar provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this application; at the same time, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method of range and reflectivity measurement applied to a laser radar, characterized in that, include: An echo signal is obtained based on the echo light reflected from the target object, wherein the echo signal is an electrical signal corresponding to the echo light; and The echo signal is measured according to a distance threshold and a reflectivity threshold, wherein the distance threshold is used to determine the distance of the target object relative to the lidar, the reflectivity threshold is used to determine the reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold.

2. The method of claim 1, wherein, The ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of the upper limit value of the interval. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds, and each first distance interval corresponds to one distance threshold. The step of measuring the echo signal based on a distance threshold includes: Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined; and The distance of the target object relative to the lidar is determined based on the first candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time.

3. The method of claim 1, wherein, The ranging range of the lidar is divided into multiple second distance intervals arranged in ascending order of the upper limit value of the interval. Between any two adjacent second distance intervals, the upper limit value of one second distance interval is equal to the lower limit value of the other second distance interval. The lidar is configured with multiple reflectivity thresholds, and each second distance interval corresponds to one reflectivity threshold. Measuring the echo signal based on a reflectivity threshold includes: Based on the echo signal and the plurality of reflectivity thresholds, determine at least one second rising edge time corresponding to the echo signal and the echo pulse width corresponding to the second rising edge time; and The reflectivity of the target object is determined based on the echo pulse width corresponding to the second candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

4. The method of claim 1, wherein, The ranging range of the lidar is divided into multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds, with each first distance interval corresponding to one distance threshold. The ranging range of the lidar is also divided into multiple second distance intervals arranged in ascending order of their upper limit values. Between any two adjacent second distance intervals, the upper limit value of one second distance interval is equal to the lower limit value of the other second distance interval. The lidar is configured with multiple reflectivity thresholds, with each second distance interval corresponding to one reflectivity threshold. The step of measuring the echo signal based on a distance threshold and measuring the echo signal based on a reflectivity threshold includes: Based on the echo signal and the plurality of distance thresholds, at least one first rising edge time corresponding to the echo signal is determined; Based on the echo signal and the plurality of reflectivity thresholds, at least one second rising edge time corresponding to the echo signal is determined; and If the time interval between the second candidate rising edge time and the first candidate rising edge time is less than a preset threshold, then the distance of the target object relative to the lidar is determined according to the first candidate rising edge time, and the reflectivity of the target object is determined according to the echo pulse width corresponding to the second candidate rising edge time. If the first distance interval corresponding to the first rising edge time determined by the distance threshold is the same as the first distance interval corresponding to the same distance threshold, then the first rising edge time is the first candidate rising edge time. If the second distance interval corresponding to the second rising edge time determined by the reflectivity threshold is the same as the second distance interval corresponding to the same reflectivity threshold, then the second rising edge time is the second candidate rising edge time.

5. The method according to any one of claims 2 to 4, characterized in that, The first distance interval corresponds to the second distance interval, and the first distance interval is the same as the corresponding second distance interval.

6. The method of claim 2, wherein, The first preset distance interval is one of the first distance intervals, the second preset distance interval is one of the second distance intervals, and the lower limit of the second preset distance interval is greater than or equal to the upper limit of the first preset distance interval. The distance threshold corresponding to the first preset distance interval and the reflectivity threshold corresponding to the second preset distance interval are the same threshold.

7. The method of claim 2, wherein, Prior to the steps of measuring the echo signal according to a distance threshold and measuring the echo signal according to a reflectivity threshold, the method includes: Based on the echo signal and multiple distance thresholds, at least one first rising edge time is determined; and Based on the at least one first rising edge time, a distance threshold for detecting distance and a reflectivity threshold for detecting reflectivity are determined; The ranging range of the lidar includes multiple first distance intervals arranged in ascending order of their upper limit values. Between any two adjacent first distance intervals, the upper limit value of one first distance interval is equal to the lower limit value of the other first distance interval. The lidar is configured with multiple distance thresholds and multiple reflectivity thresholds, with each first distance interval corresponding to one distance threshold and one reflectivity threshold.

8. A laser signal processing device, characterized by include: A signal transceiver module is used to obtain an echo signal based on the echo light reflected from a target object, wherein the echo signal is an electrical signal corresponding to the echo light; and A signal processing module is used to measure the echo signal according to a distance threshold and a reflectivity threshold, wherein the distance threshold is used to determine the distance of the target object relative to the lidar, the reflectivity threshold is used to determine the reflectivity of the target object, and the reflectivity threshold is higher than the distance threshold.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that When the computer program is run on a computer, it causes the computer to perform the distance and reflectivity measurement method as described in any one of claims 1 to 7.

10. A lidar, comprising: The device includes a transmitting unit, a receiving unit, a memory, and a processor. The transmitting unit is used to emit a detection laser towards a target object, the receiving unit is used to receive the echo light reflected from the target object, the processor and the memory store a computer program, and the processor executes the distance and reflectivity measurement method as described in any one of claims 1 to 7 by calling the computer program.

Images