Lidar reflectivity calibration method, measurement method, and related devices

Abstract

Embodiments of the present application provide a laser radar reflectivity calibration method, a measurement method and related devices, wherein the calibration method constructs a curve equation between pulse width and light energy by using echo data under fixed gain, and constructs a curve equation between distance and dynamic gain by using echo data under fixed gain and echo data under dynamic gain, then uses the two curve equations to calculate the distance calibration value and light energy calculation value corresponding to one echo data under dynamic gain, then uses the relationship between reflectivity, distance and light energy to calculate the current reflectivity calculation value based on the distance calibration value and the light energy calculation value, that is, the reflectivity calculation value under dynamic gain is obtained, and finally the reflectivity calculation value and the actual reflectivity are calibrated to obtain the calibration relationship between the reflectivity calculation value and the actual reflectivity of the laser radar under dynamic gain.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, and more specifically, to a lidar reflectivity calibration method, measurement method, and related apparatus. Background Technology

[0002] High-performance lidar boasts high measurement accuracy, especially high-performance multi-line lidar, which can output not only three-dimensional coordinate information but also the surface reflectivity information of the detected target. To accurately output target reflectivity information, the lidar's reflectivity measurement system needs to be calibrated at the factory. A typical calibration method involves placing a standard target plate with known reflectivity in a standard field. This target plate contains multiple reflectivity values ​​exhibited in a multi-gradient or continuously varying manner. This allows the lidar to calibrate the original detection value using the known standard reflectivity value of the target plate when it detects a specified reflectivity area, thus establishing a one-to-one mapping between the standard reflectivity value and the original detection value.

[0003] Dynamic gain technology is a technique to improve the measurement performance of lidar. The above-mentioned scheme can calibrate the reflectivity of lidar, but it does not take into account the impact of dynamic gain on reflectivity calibration. Therefore, directly applying it to a lidar system with dynamic gain will lead to inaccurate lidar reflectivity calibration results, thereby affecting the lidar's accuracy in detecting the reflectivity of targets. Summary of the Invention

[0004] In view of this, in order to solve the technical problem that the reflectivity calibration method in the prior art does not take into account the influence of dynamic gain on reflectivity calibration, and is directly applied to the lidar system under dynamic gain, resulting in inaccurate lidar reflectivity calibration results and reflectivity measurement results of the target, the purpose of this invention is to provide a lidar reflectivity calibration method, measurement method and related device under dynamic gain.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0006] A first aspect of the present invention provides a method for calibrating the reflectivity of a lidar, comprising:

[0007] Fixed gain echo data and dynamic gain echo data were obtained by the lidar detecting calibration plates at different calibration distances under fixed gain and dynamic gain conditions, respectively.

[0008] Based on the fixed-gain echo data, a first relationship curve equation between pulse width and optical energy is constructed.

[0009] Based on the fixed-gain echo data and the dynamic-gain echo data, a second relationship curve equation between distance and dynamic gain is constructed.

[0010] Obtain one of the dynamic gain echo data to calculate the corresponding distance calibration value and dynamic gain pulse width value;

[0011] The corresponding dynamic gain value is calculated based on the distance calibration value using the second relationship curve equation.

[0012] The fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value.

[0013] The corresponding optical energy value is calculated based on the fixed gain equivalent pulse width using the first relationship curve equation.

[0014] The reflectance value is calculated based on the distance calibration value and the light energy calculation value.

[0015] The calculated reflectance value is calibrated based on the actual reflectance of the calibration plate to obtain the calibration relationship between the calculated reflectance value and the actual reflectance of the lidar under dynamic gain.

[0016] This invention constructs a curve equation between pulse width and optical energy using echo data under fixed gain, and a curve equation between distance and dynamic gain using echo data under both fixed and dynamic gain. Then, based on a distance calibration value and optical energy calculation value corresponding to an echo data point under dynamic gain, these two curve equations are used. Next, using the relationship between reflectivity, distance, and optical energy, the current reflectivity calculation value is obtained based on the distance calibration value and the optical energy calculation value; that is, the reflectivity calculation value under dynamic gain is obtained. Finally, this calculated reflectivity value is calibrated with the actual reflectivity to obtain... The calibration relationship between the calculated and actual reflectance of a lidar under dynamic gain allows the calibration relationship obtained through the lidar reflectance calibration method provided in this invention to be directly applied to lidar systems under dynamic gain. This effectively avoids the problem in the prior art where the reflectance calibration method does not consider the impact of dynamic gain on reflectance calibration and is directly applied to lidar systems under dynamic gain, resulting in inaccurate lidar reflectance calibration results and target reflectance measurement results. This improves the accuracy and precision of lidar reflectance measurement of targets under dynamic gain.

[0017] Optionally, the step of constructing the first relationship curve equation between pulse width and optical energy based on the fixed gain echo data includes:

[0018] Based on the fixed gain echo data processing, multiple sets of first measurement data under different calibration distances are obtained. Each set of first measurement data includes the pulse width value and light energy value corresponding to the same calibration distance.

[0019] Using pulse width as the independent variable and light energy as the dependent variable, a first relationship curve equation between pulse width and light energy is constructed based on the multiple sets of first measurement data.

[0020] Therefore, by adopting the above-mentioned construction scheme for the first relation curve equation, the construction process of the first relation curve equation can be simplified, thereby improving the efficiency of equation construction.

[0021] Optionally, the step of constructing a second relationship curve equation between distance and dynamic gain based on the fixed-gain echo data and the dynamic-gain echo data includes:

[0022] Based on the fixed gain echo data processing, multiple sets of second measurement data under different calibration distances are obtained. Each set of second measurement data includes a distance value and a fixed gain pulse width value corresponding to the same calibration distance.

[0023] Based on the dynamic gain echo data processing, multiple sets of third measurement data are obtained that correspond one-to-one with the multiple sets of second measurement data; each set of third measurement data corresponds to the same calibration distance as its corresponding second measurement data, and each set of third measurement data includes a distance value and a dynamic gain pulse width value corresponding to the same calibration distance;

[0024] Based on the multiple sets of second measurement data and the multiple sets of third measurement data, a second relationship curve equation between distance and dynamic gain is constructed.

[0025] Therefore, by adopting the above-mentioned second relationship curve equation construction scheme, the distance value and fixed gain pulse width value under fixed gain are combined with the distance value and dynamic gain pulse width value under dynamic gain to construct the curve equation between distance and dynamic gain. This helps to ensure the accuracy of the obtained dynamic gain, and thus improves the correctness of the constructed curve equation between distance and dynamic gain.

[0026] Optionally, the step of constructing a second relationship curve equation between distance and dynamic gain based on the plurality of sets of second measurement data and the plurality of sets of third measurement data includes:

[0027] Using distance as the independent variable and fixed gain pulse width as the dependent variable, a first curve equation between distance and fixed gain pulse width is constructed based on the multiple sets of second measurement data.

[0028] Using distance as the independent variable and dynamic gain pulse width as the dependent variable, a second curve equation between distance and dynamic gain pulse width is constructed based on the multiple sets of third measurement data.

[0029] The second relationship curve equation is constructed based on the ratio of the first curve equation and the second curve equation.

[0030] Therefore, by first constructing the first curve equation between distance and fixed gain pulse width, and the second curve equation between distance and dynamic gain pulse width, and then using the ratio of these two curve equations to construct the second relationship curve equation, the method of ratio cancellation is used to obtain the second relationship curve equation between distance and dynamic gain. This not only simplifies the construction process of the second relationship curve equation, but also further ensures the accuracy of the obtained dynamic gain, thereby ensuring the accuracy of the second relationship curve equation.

[0031] Optionally, the step of constructing a second relationship curve equation between distance and dynamic gain based on the plurality of sets of second measurement data and the plurality of sets of third measurement data includes:

[0032] The ratio of the fixed gain pulse width value to the dynamic gain pulse width value corresponding to the same calibration distance is calculated to obtain multiple dynamic gain values; the calibration distances corresponding to the multiple dynamic gain values ​​are different from each other;

[0033] Using distance as the independent variable and dynamic gain as the dependent variable, the equation of the second relationship curve is constructed.

[0034] Therefore, by directly calculating the ratio of the fixed gain pulse width value to the dynamic gain pulse width value corresponding to the same calibration distance, and since there are multiple sets of corresponding fixed gain pulse width values ​​and dynamic gain pulse width values, with different sets corresponding to different calibration distances, multiple dynamic gain values ​​corresponding to different calibration distances can be quickly obtained. Then, based on the correspondence between the dynamic gain value and the calibration distance, the second relationship curve equation can be constructed. Compared with the second relationship curve equation construction scheme in the previous embodiment, it is not necessary to first construct the first curve equation and the second curve equation to achieve the construction of the second relationship curve equation. Therefore, the construction of the second relationship curve equation in this embodiment has higher efficiency.

[0035] Optionally, the step of calibrating the calculated reflectance value based on the actual reflectance of the calibration plate includes:

[0036] The calculated reflectance value is mapped to the corresponding actual reflectance to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

[0037] Therefore, by mapping the calculated reflectance value to the corresponding actual reflectance, the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain can be obtained. This allows the actual reflectance of the target to be obtained based on this calibration relationship once the calculated reflectance value is known, which helps to improve the accuracy and precision of the actual reflectance measurement.

[0038] Optionally, the step of calibrating the calculated reflectance value based on the actual reflectance of the calibration plate includes:

[0039] Obtain the actual reflectance corresponding to the calculated reflectance value;

[0040] Based on the known fixed gain calibration relationship, the deviation between the fixed gain reflectance corresponding to the calculated reflectance value and the actual reflectance is determined; wherein, the fixed gain calibration relationship is used to characterize the mapping relationship between the calculated reflectance value under fixed gain and the actual reflectance under fixed gain.

[0041] Based on the deviation, the reflectance values ​​of each fixed gain in the fixed gain calibration relationship are corrected to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

[0042] Therefore, by using the calculated reflectance value and the actual reflectance obtained from a single measurement, combined with the known fixed-gain calibration relationship, the fixed-gain calibration relationship can be transformed into a dynamic-gain calibration relationship. This allows the actual reflectance corresponding to different calculated reflectance values ​​under dynamic gain to be obtained in the prior calibration stage without the need to prepare calibration boards containing multiple reflectances or to perform multiple calculations and calibrations of different reflectance values. This greatly reduces the preparation and calculation work in the calibration stage and significantly improves the efficiency of calibrating the calculated reflectance values ​​for targets with different reflectances under dynamic gain.

[0043] A second aspect of the present invention provides a method for measuring reflectance, comprising:

[0044] Acquire echo data obtained from the detection of targets by lidar;

[0045] When the echo data is the echo data of the lidar under dynamic gain, the corresponding distance measurement value and dynamic gain pulse width value are calculated based on the echo data.

[0046] The corresponding dynamic gain value is calculated based on the distance measurement value using the pre-stored second relationship curve equation;

[0047] The fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value.

[0048] The corresponding optical energy value is calculated based on the fixed gain equivalent pulse width using the pre-stored first relationship curve equation.

[0049] The reflectance value is calculated based on the distance measurement value and the light energy calculation value.

[0050] Based on the calibration relationship between the pre-stored calculated reflectance value under dynamic gain and the actual reflectance, the actual reflectance corresponding to the calculated reflectance value is obtained to obtain the reflectance of the target;

[0051] Wherein, the first relation curve equation is the first relation curve equation in the lidar reflectivity calibration method provided by any one of the first aspects above, and the second relation curve equation is the second relation curve equation in the lidar reflectivity calibration method provided by any one of the first aspects above; the calibration relationship is obtained by the lidar reflectivity calibration method provided by any one of the first aspects above.

[0052] A third aspect of the present invention provides a lidar reflectivity calibration device, comprising:

[0053] The acquisition module is configured to acquire fixed-gain echo data and dynamic-gain echo data obtained by the lidar detecting calibration boards at different calibration distances under fixed and dynamic gain conditions.

[0054] The construction module is configured to: construct a first relationship curve equation between pulse width and optical energy based on the fixed gain echo data; and construct a second relationship curve equation between distance and dynamic gain based on the fixed gain echo data and the dynamic gain echo data.

[0055] The calibration module is configured to: acquire one of the dynamic gain echo data to calculate the corresponding range calibration value and dynamic gain pulse width value; calculate the corresponding dynamic gain value based on the range calibration value using the second relationship curve equation; calculate the fixed gain equivalent pulse width based on the dynamic gain pulse width value and the dynamic gain value; calculate the corresponding optical energy calculation value based on the fixed gain equivalent pulse width using the first relationship curve equation; calculate the reflectivity calculation value based on the range calibration value and the optical energy calculation value; calibrate the reflectivity calculation value based on the actual reflectivity of the calibration plate to obtain the calibration relationship between the reflectivity calculation value and the actual reflectivity of the lidar under dynamic gain.

[0056] A fourth aspect of the present invention provides a reflectivity measuring device, comprising:

[0057] The acquisition module is configured to acquire echo data obtained by the lidar from the target detection.

[0058] The calculation module is configured to: when the echo data is echo data of a lidar under dynamic gain, calculate the corresponding distance measurement value and dynamic gain pulse width value based on the echo data; calculate the corresponding dynamic gain value based on the distance measurement value using a pre-stored second relationship curve equation; calculate the fixed gain equivalent pulse width based on the dynamic gain pulse width value and the dynamic gain value; calculate the corresponding optical energy calculation value based on the fixed gain equivalent pulse width using a pre-stored first relationship curve equation; calculate the reflectivity calculation value based on the distance measurement value and the optical energy calculation value; and obtain the actual reflectivity corresponding to the calculated reflectivity value based on the pre-stored calibration relationship between the calculated reflectivity value under dynamic gain and the actual reflectivity, so as to obtain the reflectivity of the target.

[0059] Wherein, the first relation curve equation is the first relation curve equation in the lidar reflectivity calibration method provided by any one of the first aspects above, and the second relation curve equation is the second relation curve equation in the lidar reflectivity calibration method provided by any one of the first aspects above; the calibration relationship is obtained by the lidar reflectivity calibration method provided by any one of the first aspects above.

[0060] A fifth aspect of the present invention provides an electronic device including a processor and a memory, the memory storing machine-executable instructions executable by the processor, the processor executing the machine-executable instructions to implement the lidar reflectivity calibration method provided in any of the first aspects above, and / or the reflectivity measurement method provided in the second aspect above.

[0061] A sixth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the lidar reflectivity calibration method provided in any of the first aspects above, and / or the reflectivity measurement method provided in the second aspect above.

[0062] Since the reflectivity measurement method, lidar reflectivity calibration device, reflectivity measurement device, electronic device, and computer-readable storage medium provided by this invention are other subject solutions corresponding to the lidar reflectivity calibration method provided by this invention, the lidar reflectivity calibration device, electronic device, and computer-readable storage medium provided by this invention also possess the beneficial technical effects produced by the lidar reflectivity calibration method described above, and will not be elaborated here.

[0063] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0064] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 This diagram illustrates a structural block diagram of an electronic device provided by an embodiment of the present invention.

[0066] Figure 2 A flowchart of a lidar reflectivity calibration method provided by an embodiment of the present invention is shown;

[0067] Figure 3 A flowchart of a reflectance measurement method provided by an embodiment of the present invention is shown;

[0068] Figure 4 This diagram illustrates the functional block diagram of a lidar reflectivity calibration device provided in an embodiment of the present invention.

[0069] Figure 5 A functional block diagram of a reflectivity measuring device provided in an embodiment of the present invention is shown. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0071] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0072] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] To address the problem that existing reflectivity calibration methods fail to consider the impact of dynamic gain on reflectivity calibration, leading to inaccurate reflectivity calibration results and target reflectivity measurements when directly applied to lidar systems under dynamic gain, this invention provides a lidar reflectivity calibration method. This method constructs a curve equation between pulse width and optical energy using echo data under fixed gain, and further constructs a curve equation between range and dynamic gain using echo data under both fixed and dynamic gain. Then, using these two curve equations, the range calibration value and optical energy calculation value corresponding to a single echo data point under dynamic gain are used. Finally, the relationship between reflectivity, range, and optical energy is used to calculate the reflectivity based on the range calibration value and the calculated optical energy value. The current reflectance calculation value is obtained, i.e., the reflectance calculation value under dynamic gain. Finally, the calculated reflectance value and the actual reflectance are calibrated to obtain the calibration relationship between the calculated reflectance value and the actual reflectance of the lidar under dynamic gain. This allows the calibration relationship obtained by the lidar reflectance calibration method provided in this embodiment of the invention to be directly applied to lidar systems under dynamic gain. This effectively avoids the problem in the prior art where the reflectance calibration method does not consider the influence of dynamic gain on reflectance calibration and is directly applied to lidar systems under dynamic gain, resulting in inaccurate lidar reflectance calibration results and target reflectance measurement results. This can improve the accuracy and precision of lidar under dynamic gain in measuring the reflectance of targets.

[0074] The lidar reflectivity calibration method provided by this invention can be applied to electronic devices. Please refer to [the relevant documentation]. Figure 1This is a structural block diagram of an electronic device. The electronic device 100 includes a memory 110, a processor 120, and a communication module 130. The memory 110, processor 120, and communication module 130 are electrically connected to each other directly or indirectly to realize data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines.

[0075] The memory is used to store programs or data. The memory may be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc.

[0076] The processor is used to read / write data or programs stored in memory and to perform the corresponding functions.

[0077] The communication module is used to establish communication connections between electronic devices and other communication terminals via a network, and to send and receive data via the network.

[0078] It should be understood that, Figure 1 The structure shown is only a schematic diagram of an electronic device; the electronic device may also include components that are larger than... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown. Figure 1 The components shown can be implemented using hardware, software, or a combination thereof.

[0079] In some embodiments, the electronic device may be a processor in a lidar system, used to process the echo data obtained by the lidar system from detecting a target using the lidar reflectivity calibration method provided in this embodiment of the invention.

[0080] The following combination Figure 2 The lidar reflectivity calibration method provided in the embodiments of the present invention will be described below. Figure 2 This is a flowchart of a lidar reflectivity calibration method provided in an embodiment of the present invention. The lidar reflectivity calibration method includes:

[0081] In step S210, fixed gain echo data and dynamic gain echo data are obtained by the lidar detecting calibration plates at different calibration distances under fixed gain and dynamic gain conditions, respectively.

[0082] In step S220, a first relationship curve equation between pulse width and optical energy is constructed based on the fixed gain echo data;

[0083] In step S230, a second relationship curve equation between distance and dynamic gain is constructed based on the fixed gain echo data and the dynamic gain echo data.

[0084] In step S240, the distance calibration value and dynamic gain pulse width value corresponding to one of the dynamic gain echo data are obtained;

[0085] In step S250, the corresponding dynamic gain value is calculated based on the distance calibration value using the second relationship curve equation.

[0086] In step S260, the fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value;

[0087] In step S270, the corresponding optical energy value is calculated based on the fixed gain equivalent pulse width using the first relationship curve equation.

[0088] In step S280, the reflectance is calculated based on the distance calibration value and the light energy calculation value.

[0089] In step S290, the calculated reflectance value is calibrated based on the actual reflectance of the calibration plate to obtain the calibration relationship between the calculated reflectance value and the actual reflectance of the lidar under dynamic gain.

[0090] The lidar reflectivity calibration method provided by this invention can be applied to lidar systems capable of target detection using dynamic gain. It can be understood that before the lidar leaves the factory or before the lidar is applied in an actual detection environment, the lidar reflectivity calculation value under dynamic gain can be calibrated using the lidar reflectivity calibration method provided in this embodiment of the invention.

[0091] To facilitate understanding of the calibration principle of the lidar reflectivity calibration method provided by this invention, the relevant reasons are first introduced:

[0092] The principle for calculating the echo power of a lidar system is as follows:

[0093]

[0094] Where G is the dynamic gain, ρ is the target surface reflectivity, P0 is the emitted laser power, and A r θ is the aperture pointing angle, θ is the angle at which the emitted laser beam is incident on the target surface, and d is the distance between the target and the lidar.

[0095] A lidar system detects a target, and the resulting echo data, after photoelectric conversion and dynamic gain control, can generate pulse width data. The specific principles are detailed in related technologies. The pulse width data is uniquely determined by the echo power of the lidar system's receiving section. As shown in the formula above, the echo power is determined by factors such as dynamic gain, target surface reflectivity, emitted laser power, aperture of the pointing angle, the angle at which the emitted laser beam strikes the target surface, and distance. Therefore, under a fixed gain, the echo power is related to the light energy, and consequently, the pulse width is also related to the light energy. To calculate the corresponding reflectivity, this invention constructs a curve equation between pulse width and light energy. Since dynamic gain is time-dependent, and distance is a factor affecting time, this invention also constructs a curve equation between distance and dynamic gain under dynamic gain to calculate the corresponding reflectivity. Based on this, the formula for calculating echo power can be decomposed as follows:

[0096] P r =f G ·f p

[0097] Among them, f G For gain, f p This refers to light energy; the formula for calculating visible light energy is:

[0098]

[0099] Based on the formula for calculating light energy, the formula for calculating reflectivity can be derived as follows:

[0100]

[0101] The meaning of each letter in the above formula can be found in the relevant introduction to the echo power calculation formula above, and will not be repeated here.

[0102] As can be seen from formula (2), except for light energy, all other parameters are system parameters and are known. Light energy can be obtained by solving the curve equation between pulse width and light energy. The pulse width under dynamic gain can be calculated by echo data. Therefore, as long as the pulse width under dynamic gain is converted into the pulse width under fixed gain, and the light energy is calculated by using the curve equation between pulse width and light energy, the light energy can include the influencing factors under dynamic gain. The reflectivity calculated based on this is the reflectivity under dynamic gain.

[0103] The following describes the process of reflectivity calibration using the lidar reflectivity calibration method provided by this invention:

[0104] First, a calibration plate with known reflectivity can be placed within the effective detection range of the lidar system at a specified distance from the detection part of the lidar system. This specified distance can be set according to calibration requirements, and this embodiment of the invention does not limit it. Next, the lidar system is configured in fixed gain mode, and one frame of echo data is acquired. Then, the lidar is configured in dynamic gain mode, and another frame of echo data is acquired. This completes the detection of the calibration plate at the current distance, forming a set of fixed gain echo data and dynamic gain echo data corresponding to the same calibration distance. Next, the calibration plate is moved to different distances, and the above echo data acquisition operation is performed again until echo data at all calibrated distance points are acquired. Thus, multiple fixed gain echo data corresponding to different calibration distances and multiple dynamic gain echo data corresponding to different calibration distances can be obtained.

[0105] After obtaining multiple fixed-gain echo data and multiple dynamic-gain echo data, these data can be stored. When calibration is required, these data can be read and calibrated.

[0106] As can be seen, in step S210 above, the acquisition of fixed gain echo data and dynamic gain echo data can occur during the acquisition process of the echo data acquisition stage, or it can occur during the data reading process after the echo data acquisition stage.

[0107] After obtaining multiple fixed-gain echo data and multiple dynamic-gain echo data in step S210, the first relationship curve equation and the second relationship curve equation can be constructed in steps S220 and S230, respectively. In this embodiment of the invention, steps S220 and S230 can be executed in parallel or sequentially, and the order of execution is not limited when executing sequentially.

[0108] For the first relationship curve equation, since the calibration distance, the reflectivity of the calibration plate and other system parameters in formula (1) are all known, the light energy can be calculated using the fixed gain echo data; and the pulse width can also be calculated using the echo data. Therefore, the pulse width value and light energy can be calculated using the fixed gain echo data, and the first relationship curve equation between the pulse width and light energy can be constructed based on the pulse width value and light energy. The specific construction principle can be the principle of curve fitting, which will not be elaborated here.

[0109] To simplify the construction process of the first relationship curve equation and improve the efficiency of equation construction, in some embodiments, step S220, which involves constructing the first relationship curve equation between pulse width and optical energy based on the fixed gain echo data, may include the following steps:

[0110] In step S221, multiple sets of first measurement data at different calibration distances are obtained based on the fixed gain echo data. Each set of first measurement data includes a pulse width value and a light energy value corresponding to the same calibration distance.

[0111] In step S222, with pulse width as the independent variable and light energy as the dependent variable, a first relationship curve equation between pulse width and light energy is constructed based on the multiple sets of first measurement data.

[0112] By calculating the pulse width and light energy for each fixed gain echo data in step S221, the first measurement data corresponding to each fixed gain echo data, namely the pulse width value and light energy value, can be obtained. Then, by performing curve fitting processing on multiple sets of first measurement data corresponding to different calibration distances in step S222, with the pulse width as the independent variable and the light energy as the dependent variable, the first relationship curve equation between the pulse width and the light energy can be obtained.

[0113] For the second relationship curve equation, since the calibration distance is known and the pulse width can be calculated from the echo data, the dynamic gain can be obtained by canceling the pulse width under fixed gain and the pulse width under dynamic gain. Therefore, curve fitting can be performed based on the correspondence between distance and dynamic gain to obtain the second relationship curve equation. The cancellation processing can be subtraction or averaging. However, the inventors have found that although subtraction or averaging can obtain the dynamic gain, the obtained dynamic gain may deviate from the actual value. For example, subtraction may result in a negative dynamic gain, causing the estimated value of the dynamic gain to change, which is inconsistent with the design of the dynamic gain, because the gain cannot be negative. Averaging does not closely match the actual dynamic gain. Therefore, to improve the accuracy of the second relationship curve equation, in some embodiments, step S230, the step of constructing the second relationship curve equation between distance and dynamic gain based on the fixed gain echo data and the dynamic gain echo data, may include the following steps:

[0114] In step S231, multiple sets of second measurement data at different calibration distances are obtained by processing the fixed gain echo data. Each set of second measurement data includes a distance value and a fixed gain pulse width value corresponding to the same calibration distance.

[0115] In step S232, multiple sets of third measurement data corresponding one-to-one with the multiple sets of second measurement data are obtained based on the dynamic gain echo data; each set of third measurement data corresponds to the same calibration distance as its corresponding second measurement data, and each set of third measurement data includes a distance value and a dynamic gain pulse width value corresponding to the same calibration distance;

[0116] In step S233, a second relationship curve equation between distance and dynamic gain is constructed based on the multiple sets of second measurement data and the multiple sets of third measurement data.

[0117] Through steps S231 and S232, multiple fixed-gain echo data and multiple dynamic-gain echo data are processed respectively to obtain multiple sets of second measurement data under fixed gain and multiple sets of third measurement data under dynamic gain. Since the multiple fixed-gain echo data correspond to different calibration distances, and the multiple dynamic-gain echo data also correspond to different calibration distances, and there is a one-to-one correspondence between the multiple fixed-gain echo data and the multiple dynamic-gain echo data, with the corresponding fixed-gain echo data and dynamic-gain echo data corresponding to the same calibration distance, multiple sets of second measurement data and multiple sets of third measurement data related to distance can be obtained through the above processing. Steps S231 and S232 can be executed in parallel or sequentially; the order of sequential execution is not limited.

[0118] After obtaining multiple sets of second and third measurement data, the second relationship curve equation can be constructed based on these measurement data. To this end, this invention proposes two construction schemes for the second relationship curve equation, as follows:

[0119] The first type:

[0120] Step S233, the step of constructing a second relationship curve equation between distance and dynamic gain based on the multiple sets of second measurement data and the multiple sets of third measurement data, may include:

[0121] In step S233-11, with distance as the independent variable and fixed gain pulse width as the dependent variable, a first curve equation between distance and fixed gain pulse width is constructed based on the multiple sets of second measurement data.

[0122] In step S233-12, with distance as the independent variable and dynamic gain pulse width as the dependent variable, a second curve equation between distance and dynamic gain pulse width is constructed based on the multiple sets of third measurement data.

[0123] In step S233-13, the second relationship curve equation is constructed based on the ratio of the first curve equation and the second curve equation.

[0124] The principles behind constructing the curve equations in steps S233-11 and S233-12 are detailed above and will not be repeated here. Furthermore, the order in which S233-11 and S233-12 are executed is not critical. After constructing the first and second curve equations through steps S233-11 and S233-12 respectively, their ratio can be directly used as the second relationship curve equation.

[0125] Therefore, by first constructing the first curve equation between distance and fixed gain pulse width, and the second curve equation between distance and dynamic gain pulse width, and then using the ratio of these two curve equations to construct the second relationship curve equation, the method of ratio cancellation to obtain the second relationship curve equation between distance and dynamic gain not only simplifies the construction process of the second relationship curve equation, but also avoids the problems of dynamic gain estimation variation and inaccuracy compared to the methods of subtraction cancellation or mean cancellation, thereby improving the accuracy of dynamic gain and ensuring the accuracy of the second relationship curve equation.

[0126] The second type:

[0127] Step S233, the step of constructing a second relationship curve equation between distance and dynamic gain based on the multiple sets of second measurement data and the multiple sets of third measurement data, may include:

[0128] In steps S233-21, the ratio of the fixed gain pulse width value to the dynamic gain pulse width value corresponding to the same calibration distance is calculated to obtain multiple dynamic gain values; the calibration distances corresponding to the multiple dynamic gain values ​​are different from each other;

[0129] In steps S233-22, the second relationship curve equation is constructed by using distance as the independent variable and dynamic gain as the dependent variable.

[0130] By utilizing steps S233-21 and S233-22, the ratio of the fixed gain pulse width value to the dynamic gain pulse width value corresponding to the same calibration distance is directly calculated. Since there are multiple sets of corresponding fixed gain pulse width values ​​and dynamic gain pulse width values, and different sets correspond to different calibration distances, multiple dynamic gain values ​​corresponding to different calibration distances can be quickly obtained. Then, based on the correspondence between the dynamic gain value and the calibration distance, the second relationship curve equation can be constructed. Compared with the first method of constructing the second relationship curve equation, it is not necessary to first construct the first curve equation and the second curve equation. The construction of the second relationship curve equation can be achieved without first constructing the first curve equation and the second curve equation. Therefore, the construction of the second relationship curve equation in this embodiment can achieve higher efficiency while ensuring accuracy.

[0131] After obtaining the first and second relationship curve equations through any of the above embodiments, the reflectivity values ​​detected by the lidar system can be calculated using the first and second relationship curve equations. The calculation process is as follows:

[0132] First, in step S240, one of the multiple dynamic echo data is selected for calculation, and the range calibration value and dynamic gain pulse width value corresponding to the dynamic echo data are obtained. The acquisition of the range calibration value and dynamic gain pulse width value can be found in relevant technologies or related records above, and will not be explained in detail here.

[0133] After obtaining the distance calibration value and dynamic gain pulse width value under dynamic gain, the distance calibration value can be substituted into the second relationship curve equation in step S250, and the current dynamic gain value can be calculated using the second relationship curve equation.

[0134] After obtaining the dynamic gain value, the fixed gain equivalent pulse width can be calculated using the dynamic gain value and the dynamic gain pulse width value in step S260. In one embodiment, the fixed gain equivalent pulse width is equal to the product of the dynamic gain pulse width value and the dynamic gain value.

[0135] After obtaining the fixed gain equivalent pulse width, step S270 can be used to substitute the fixed gain equivalent pulse width into the first relation curve equation, and the current optical energy value can be calculated using the first relation curve equation.

[0136] After obtaining the calculated value of light energy, the calculated value of reflectance can be obtained by using the above formula (2) in step S280.

[0137] After obtaining the calculated reflectance value, step S290 can be used to calibrate the calculated reflectance value using the actual reflectance of the calibration plate. This calibration involves mapping the calculated reflectance value to the actual reflectance. In subsequent reflectance detection using a lidar system, if the reflectance value calculated by the lidar system is the same as or close to the calculated reflectance value, the actual reflectance can be output, indicating that the target's reflectance is the actual reflectance, thus achieving the detection of the target surface's reflectance. Therefore, step S290, calibrating the calculated reflectance value based on the actual reflectance of the calibration plate, can include the following steps:

[0138] In step S290-1, the calculated reflectance value and the corresponding actual reflectance are mapped to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

[0139] This completes the calibration between the calculated reflectance value and the actual reflectance. If there is a need to detect targets with different reflectances, multiple calibration plates with different reflectances can be used, or a single calibration plate containing different reflectances can be used, following the placement procedures for the calibration plates described above. The following example uses multiple calibration plates. First, one calibration plate with different reflectances can be placed, and dynamic gain echo data can be collected. Then, through steps S240-S290, the dynamic gain echo data of this calibration plate with different reflectances is processed to obtain the calculated reflectance value of that calibration plate. This calculated reflectance value is then mapped to the corresponding actual reflectance to obtain a new calibration relationship. This process is repeated until the calculated reflectance values ​​and actual reflectances of all calibration plates with different reflectances are calibrated, thus obtaining multiple sets of calibration relationships. For ease of storage and subsequent retrieval, these multiple sets of calibration relationships can be recorded in tabular form, forming a calibration relationship table. In subsequent applications, the actual reflectance with a mapping relationship can be directly searched from the above calibration relationship table based on the currently calculated reflectance value to obtain the reflectance of the target surface.

[0140] In addition to the calibration method described above, this embodiment of the invention also provides another calibration method, namely, the step of calibrating the calculated reflectance value based on the actual reflectance of the calibration plate in step S290 may include:

[0141] In steps S290-21, the actual reflectance corresponding to the calculated reflectance value is obtained;

[0142] In steps S290-22, based on the known fixed gain calibration relationship, the deviation between the fixed gain reflectance corresponding to the calculated reflectance value and the actual reflectance is determined; wherein, the fixed gain calibration relationship is used to characterize the mapping relationship between the calculated reflectance value under fixed gain and the actual reflectance under fixed gain;

[0143] In steps S290-23, the fixed gain reflectivity in the fixed gain calibration relationship is corrected according to the deviation, so as to obtain the calibration relationship between the calculated reflectivity value and the actual reflectivity under dynamic gain.

[0144] The calibration process described in steps S290-21 to S290-23 is as follows:

[0145] After obtaining the calculated reflectance value through step S280, since the reflectance of the calibration plate is known, the actual reflectance corresponding to the calculated reflectance value can be obtained through steps S290-21.

[0146] After obtaining the actual reflectivity through step S290-21, since lidar suppliers or developers generally retain the calibration relationship between the calculated reflectivity under fixed gain and the actual reflectivity (i.e., the fixed gain calibration relationship mentioned above), when the efficiency requirement for obtaining the calibration relationship under dynamic gain is very high, the dynamic gain calibration relationship can be quickly generated through steps S290-22 to S290-23 using the currently calculated reflectivity and its actual reflectivity, and the fixed gain calibration relationship. That is, the calibration relationship between the calculated reflectivity and the actual reflectivity under dynamic gain. Specifically, firstly, through step S290-22, the fixed gain reflectance corresponding to the reflectance calculated in step S290-21 is obtained from the fixed gain calibration relationship. Then, the deviation between the fixed gain reflectance and the actual reflectance is calculated. Next, through step S290-23, the deviation is used to correct all fixed gain reflectances in the fixed gain calibration relationship. For example, the difference between each fixed gain reflectance and the deviation is used as the corrected value. The corrected value is the actual reflectance under dynamic gain. In the fixed gain calibration relationship, the reflectance calculated value does not need to be changed. Thus, the calibration relationship between the reflectance calculated value and the actual reflectance under dynamic gain can be obtained.

[0147] Therefore, through steps S290-21 to S290-23, the calculated reflectance value and the actual reflectance obtained from a single measurement are used in conjunction with the known fixed gain calibration relationship to convert the fixed gain calibration relationship into a dynamic gain calibration relationship. This allows the actual reflectance corresponding to different calculated reflectance values ​​under dynamic gain to be known in the prior calibration stage without the need to prepare calibration boards containing multiple reflectances or to perform multiple calculations and calibrations of different reflectance values. This greatly reduces the preparation and calculation work in the calibration stage and significantly improves the efficiency of calibrating the calculated reflectance values ​​for targets with different reflectances under dynamic gain.

[0148] Once the calibration relationship is obtained, the lidar system can be applied to real-world scenarios to detect the reflectivity of targets. Based on this, embodiments of the present invention also provide a reflectivity measurement method, such as... Figure 3 As shown, Figure 3 This is a flowchart of a reflectance measurement method provided in an embodiment of the present invention, the method comprising:

[0149] In step S310, the echo data obtained by the lidar in detecting the target is acquired;

[0150] In step S320, when the echo data is the echo data of the lidar under dynamic gain, the corresponding distance measurement value and dynamic gain pulse width value are calculated based on the echo data.

[0151] In step S330, the corresponding dynamic gain value is calculated based on the distance measurement value using the pre-stored second relationship curve equation;

[0152] In step S340, the fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value;

[0153] In step S350, the corresponding optical energy value is calculated based on the fixed gain equivalent pulse width using the pre-stored first relationship curve equation.

[0154] In step S360, the reflectance is calculated based on the distance measurement value and the light energy calculation value.

[0155] In step S370, the actual reflectance corresponding to the calculated reflectance is obtained based on the calibration relationship between the pre-stored calculated reflectance value and the actual reflectance under dynamic gain, so as to obtain the reflectance of the target.

[0156] Wherein, the first relation curve equation in step S350 is the first relation curve equation in any embodiment of the above-mentioned lidar reflectivity calibration method, the second relation curve equation in step S330 is the second relation curve equation in any embodiment of the above-mentioned lidar reflectivity calibration method, and the calibration relationship in step S370 is obtained through any embodiment of the above-mentioned lidar reflectivity calibration method.

[0157] Furthermore, the technical principles of steps S310 to S370 can be found in the relevant descriptions in the above-mentioned embodiments of the lidar reflectivity calibration method, and will not be repeated here.

[0158] It is worth noting that the technical features or technical solutions in any of the above embodiments of the present invention can be combined with each other, as long as there is no contradiction in the combination.

[0159] To perform the corresponding steps in the embodiments and various possible methods of the lidar reflectivity calibration method, an implementation of a lidar reflectivity calibration device is given below. Optionally, this lidar reflectivity calibration device can adopt the above-described... Figure 1 The device structure of the electronic device is shown. Further, please refer to... Figure 4 , Figure 4 This is a functional block diagram of a lidar reflectivity calibration device provided in an embodiment of the present invention. It should be noted that the lidar reflectivity calibration device provided in this embodiment has the same basic principle and technical effects as the aforementioned related embodiments. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the aforementioned related embodiments. The lidar reflectivity calibration device 400 includes:

[0160] The acquisition module 410 is configured to acquire fixed-gain echo data and dynamic-gain echo data obtained by the lidar detecting calibration plates at different calibration distances under fixed and dynamic gain conditions.

[0161] The construction module 420 is configured to: construct a first relationship curve equation between pulse width and optical energy based on the fixed gain echo data; and construct a second relationship curve equation between distance and dynamic gain based on the fixed gain echo data and the dynamic gain echo data.

[0162] The calibration module 430 is configured to: acquire a distance calibration value and a dynamic gain pulse width value corresponding to one of the dynamic gain echo data; calculate the corresponding dynamic gain value based on the distance calibration value using the second relationship curve equation; calculate the fixed gain equivalent pulse width based on the dynamic gain pulse width value and the dynamic gain value; calculate the corresponding optical energy calculation value based on the fixed gain equivalent pulse width using the first relationship curve equation; calculate the reflectivity calculation value based on the distance calibration value and the optical energy calculation value; calibrate the reflectivity calculation value based on the actual reflectivity of the calibration plate to obtain the calibration relationship between the reflectivity calculation value and the actual reflectivity of the lidar under dynamic gain.

[0163] In some embodiments, the process by which the construction module 420 constructs a first relationship curve equation between pulse width and optical energy based on the fixed gain echo data includes:

[0164] Based on the fixed gain echo data processing, multiple sets of first measurement data under different calibration distances are obtained. Each set of first measurement data includes the pulse width value and light energy value corresponding to the same calibration distance.

[0165] Using pulse width as the independent variable and light energy as the dependent variable, a first relationship curve equation between pulse width and light energy is constructed based on the multiple sets of first measurement data.

[0166] In some embodiments, the process by which the construction module 420 constructs the second relationship curve equation between distance and dynamic gain includes:

[0167] Based on the fixed gain echo data processing, multiple sets of second measurement data under different calibration distances are obtained. Each set of second measurement data includes a distance value and a fixed gain pulse width value corresponding to the same calibration distance.

[0168] Based on the dynamic gain echo data processing, multiple sets of third measurement data are obtained that correspond one-to-one with the multiple sets of second measurement data; each set of third measurement data corresponds to the same calibration distance as its corresponding second measurement data, and each set of third measurement data includes a distance value and a dynamic gain pulse width value corresponding to the same calibration distance;

[0169] Based on the multiple sets of second measurement data and the multiple sets of third measurement data, a second relationship curve equation between distance and dynamic gain is constructed.

[0170] In some embodiments, the process by which the construction module 420 constructs a second relationship curve equation between distance and dynamic gain based on the plurality of sets of second measurement data and the plurality of sets of third measurement data includes:

[0171] Using distance as the independent variable and fixed gain pulse width as the dependent variable, a first curve equation between distance and fixed gain pulse width is constructed based on the multiple sets of second measurement data.

[0172] Using distance as the independent variable and dynamic gain pulse width as the dependent variable, a second curve equation between distance and dynamic gain pulse width is constructed based on the multiple sets of third measurement data.

[0173] The second relationship curve equation is constructed based on the ratio of the first curve equation and the second curve equation.

[0174] In other embodiments, the process by which the construction module 420 constructs a second relationship curve equation between distance and dynamic gain based on the plurality of sets of second measurement data and the plurality of sets of third measurement data includes:

[0175] The ratio of the fixed gain pulse width value to the dynamic gain pulse width value corresponding to the same calibration distance is calculated to obtain multiple dynamic gain values; the calibration distances corresponding to the multiple dynamic gain values ​​are different from each other;

[0176] Using distance as the independent variable and dynamic gain as the dependent variable, the equation of the second relationship curve is constructed.

[0177] In some embodiments, the process by which the calibration module 430 calibrates the calculated reflectance value based on the actual reflectance of the calibration plate includes: mapping the currently calculated reflectance value to the corresponding actual reflectance to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

[0178] In other embodiments, the process by which the calibration module 430 calibrates the calculated reflectance value based on the actual reflectance of the calibration plate includes:

[0179] Obtain the actual reflectance corresponding to the calculated reflectance value;

[0180] Based on the known fixed gain calibration relationship, the deviation between the fixed gain reflectance corresponding to the calculated reflectance value and the actual reflectance is determined; wherein, the fixed gain calibration relationship is used to characterize the mapping relationship between the calculated reflectance value under fixed gain and the actual reflectance under fixed gain.

[0181] Based on the deviation, the reflectance values ​​of each fixed gain in the fixed gain calibration relationship are corrected to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

[0182] Optionally, the above modules can be stored in the form of software or firmware. Figure 1 The memory shown is either stored in or embedded in the operating system (OS) of the electronic device, and can be... Figure 1 The processor executes the commands. Meanwhile, the data and program code required to execute these modules can be stored in memory.

[0183] To perform the corresponding steps in the embodiments of the reflectance measurement method and various possible methods, an implementation of a reflectance measurement device is given below. Optionally, the reflectance measurement device can adopt the above-described... Figure 1 The device structure of the electronic device is shown. Further, please refer to... Figure 5 , Figure 5 This is a functional block diagram of a reflectance measuring device provided in an embodiment of the present invention. It should be noted that the basic principle and technical effects of the reflectance measuring device provided in this embodiment are the same as those in the aforementioned related embodiments. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the aforementioned related embodiments. The reflectance measuring device 500 includes:

[0184] The acquisition module 510 is configured to acquire echo data obtained by the lidar from the target detection;

[0185] The calculation module 520 is configured to: when the echo data is echo data of a lidar under dynamic gain, calculate the corresponding distance measurement value and dynamic gain pulse width value based on the echo data; calculate the corresponding dynamic gain value based on the distance measurement value using a pre-stored second relationship curve equation; calculate the fixed gain equivalent pulse width based on the dynamic gain pulse width value and the dynamic gain value; calculate the corresponding optical energy calculation value based on the fixed gain equivalent pulse width using a pre-stored first relationship curve equation; calculate the reflectivity calculation value based on the distance measurement value and the optical energy calculation value; and obtain the actual reflectivity corresponding to the calculated reflectivity value based on the pre-stored calibration relationship between the calculated reflectivity value under dynamic gain and the actual reflectivity, so as to obtain the reflectivity of the target.

[0186] In the calculation module 520, the first relationship curve equation is the first relationship curve equation in any embodiment of the above-described lidar reflectivity calibration method, and the second relationship curve equation is the second relationship curve equation in any embodiment of the above-described lidar reflectivity calibration method; the calibration relationship is obtained through any embodiment of the above-described lidar reflectivity calibration method.

[0187] Optionally, the above modules can be stored in the form of software or firmware. Figure 1 The memory shown is either stored in or embedded in the operating system (OS) of the electronic device, and can be... Figure 1 The processor executes the commands. Meanwhile, the data and program code required to execute these modules can be stored in memory.

[0188] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0189] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0190] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0191] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calibrating the reflectivity of a lidar system, characterized in that, include: Fixed gain echo data and dynamic gain echo data were obtained by the lidar detecting calibration plates at different calibration distances under fixed gain and dynamic gain conditions, respectively. Based on the fixed-gain echo data, a first relationship curve equation between pulse width and optical energy is constructed. Based on the fixed-gain echo data and the dynamic-gain echo data, a second relationship curve equation between distance and dynamic gain is constructed. Obtain the distance calibration value and dynamic gain pulse width value corresponding to one of the dynamic gain echo data; The corresponding dynamic gain value is calculated based on the distance calibration value using the second relationship curve equation. The fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value. The corresponding optical energy value is calculated based on the fixed gain equivalent pulse width using the first relationship curve equation. The reflectance value is calculated based on the distance calibration value and the light energy calculation value. The calculated reflectance value is calibrated based on the actual reflectance of the calibration plate to obtain the calibration relationship between the calculated reflectance value and the actual reflectance of the lidar under dynamic gain.

2. The method according to claim 1, characterized in that, The step of constructing the first relationship curve equation between pulse width and optical energy based on the fixed gain echo data includes: Based on the fixed gain echo data processing, multiple sets of first measurement data under different calibration distances are obtained. Each set of first measurement data includes the pulse width value and light energy value corresponding to the same calibration distance. Using pulse width as the independent variable and light energy as the dependent variable, a first relationship curve equation between pulse width and light energy is constructed based on the multiple sets of first measurement data.

3. The method according to claim 1, characterized in that, The step of constructing a second relationship curve equation between distance and dynamic gain based on the fixed gain echo data and the dynamic gain echo data includes: Based on the fixed gain echo data processing, multiple sets of second measurement data under different calibration distances are obtained. Each set of second measurement data includes a distance value and a fixed gain pulse width value corresponding to the same calibration distance. Based on the dynamic gain echo data processing, multiple sets of third measurement data are obtained that correspond one-to-one with the multiple sets of second measurement data; each set of third measurement data corresponds to the same calibration distance as its corresponding second measurement data, and each set of third measurement data includes a distance value and a dynamic gain pulse width value corresponding to the same calibration distance; Based on the multiple sets of second measurement data and the multiple sets of third measurement data, a second relationship curve equation between distance and dynamic gain is constructed.

4. The method according to claim 3, characterized in that, The step of constructing a second relationship curve equation between distance and dynamic gain based on the multiple sets of second measurement data and the multiple sets of third measurement data includes: Using distance as the independent variable and fixed gain pulse width as the dependent variable, a first curve equation between distance and fixed gain pulse width is constructed based on the multiple sets of second measurement data. Using distance as the independent variable and dynamic gain pulse width as the dependent variable, a second curve equation between distance and dynamic gain pulse width is constructed based on the multiple sets of third measurement data. The second relationship curve equation is constructed based on the ratio of the first curve equation and the second curve equation.

5. The method according to claim 3, characterized in that, The step of constructing a second relationship curve equation between distance and dynamic gain based on the multiple sets of second measurement data and the multiple sets of third measurement data includes: The ratio of the fixed gain pulse width value to the dynamic gain pulse width value corresponding to the same calibration distance is calculated to obtain multiple dynamic gain values; the calibration distances corresponding to the multiple dynamic gain values ​​are different from each other; Using distance as the independent variable and dynamic gain as the dependent variable, the equation of the second relationship curve is constructed.

6. The method according to any one of claims 1 to 5, characterized in that, The step of calibrating the calculated reflectance value based on the actual reflectance of the calibration plate includes: The calculated reflectance value is mapped to the corresponding actual reflectance to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

7. The method according to any one of claims 1 to 5, characterized in that, The step of calibrating the calculated reflectance value based on the actual reflectance of the calibration plate includes: Obtain the actual reflectance corresponding to the calculated reflectance value; Based on the known fixed gain calibration relationship, the deviation between the fixed gain reflectance corresponding to the calculated reflectance value and the actual reflectance is determined; wherein, the fixed gain calibration relationship is used to characterize the mapping relationship between the calculated reflectance value under fixed gain and the actual reflectance under fixed gain. Based on the deviation, the reflectance values ​​of each fixed gain in the fixed gain calibration relationship are corrected to obtain the calibration relationship between the calculated reflectance value and the actual reflectance under dynamic gain.

8. A method for measuring reflectance, characterized in that, include: Acquire echo data obtained from the detection of targets by lidar; When the echo data is the echo data of the lidar under dynamic gain, the corresponding distance measurement value and dynamic gain pulse width value are calculated based on the echo data. The corresponding dynamic gain value is calculated based on the distance measurement value using the pre-stored second relationship curve equation; The fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value. The corresponding optical energy value is calculated based on the fixed gain equivalent pulse width using the pre-stored first relationship curve equation. The reflectance value is calculated based on the distance measurement value and the light energy calculation value. Based on the calibration relationship between the pre-stored calculated reflectance value under dynamic gain and the actual reflectance, the actual reflectance corresponding to the calculated reflectance value is obtained to obtain the reflectance of the target; Wherein, the first relation curve equation is the first relation curve equation of any one of claims 1 to 7, and the second relation curve equation is the second relation curve equation of any one of claims 1 to 7; the calibration relationship is obtained by the method of any one of claims 1 to 7.

9. A lidar reflectivity calibration device, characterized in that, include: The acquisition module is configured to acquire fixed-gain echo data and dynamic-gain echo data obtained by the lidar detecting calibration boards at different calibration distances under fixed and dynamic gain conditions. The construction module is configured to: construct a first relationship curve equation between pulse width and optical energy based on the fixed gain echo data; and construct a second relationship curve equation between distance and dynamic gain based on the fixed gain echo data and the dynamic gain echo data. The calibration module is configured to: acquire the distance calibration value and dynamic gain pulse width value corresponding to one of the dynamic gain echo data; and calculate the corresponding dynamic gain value based on the distance calibration value using the second relationship curve equation. The fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value; the corresponding optical energy is calculated based on the fixed gain equivalent pulse width using the first relationship curve equation; the reflectivity is calculated based on the distance calibration value and the optical energy calculation value; the reflectivity calculation value is calibrated based on the actual reflectivity of the calibration plate to obtain the calibration relationship between the reflectivity calculation value and the actual reflectivity of the lidar under dynamic gain.

10. A reflectivity measuring device, characterized in that, include: The acquisition module is configured to acquire echo data obtained by the lidar from the target detection. The calculation module is configured to: when the echo data is the echo data of the lidar under dynamic gain, calculate the corresponding distance measurement value and dynamic gain pulse width value based on the echo data; and calculate the corresponding dynamic gain value based on the distance measurement value using a pre-stored second relationship curve equation. The fixed gain equivalent pulse width is calculated based on the dynamic gain pulse width value and the dynamic gain value; the corresponding optical energy is calculated based on the fixed gain equivalent pulse width using the pre-stored first relationship curve equation; and the reflectivity is calculated based on the distance measurement value and the optical energy calculation value. Based on the calibration relationship between the pre-stored calculated reflectance value under dynamic gain and the actual reflectance, the actual reflectance corresponding to the calculated reflectance value is obtained to obtain the reflectance of the target; Wherein, the first relation curve equation is the first relation curve equation of any one of claims 1 to 7, and the second relation curve equation is the second relation curve equation of any one of claims 1 to 7; the calibration relationship is obtained by the lidar reflectivity calibration method of any one of claims 1 to 7.

11. An electronic device, characterized in that, It includes a processor and a memory, the memory storing machine-executable instructions that can be executed by the processor, the processor executing the machine-executable instructions to implement the lidar reflectivity calibration method of any one of claims 1-7, and / or the reflectivity measurement method of claim 8.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the lidar reflectivity calibration method as described in any one of claims 1-7, and / or the reflectivity measurement method as described in claim 8.

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