Photon receiving simulation method of time-of-flight measurement system and electronic device

Abstract

The embodiment of the application is suitable for the technical field of computers, and provides a photon receiving simulation method of a time-of-flight measurement system and an electronic device, including: obtaining the number of incident photons reaching a detection array at each analysis time in an analysis period; obtaining the number of received photons corresponding to each detection unit at the analysis time based on the number of incident photons and the distribution area of the incident photons; obtaining the number of times of triggering of a photon event corresponding to the detection array at the analysis time according to the number of received photons corresponding to each detection unit at the analysis time and a photon event triggering model; and accumulating the number of times of triggering of the photon event corresponding to the detection array in the analysis period to obtain histogram data corresponding to the detection array. The method provided in the embodiment of the application can improve the accuracy of photon receiving simulation.

Description

Technical Field

[0001] This application belongs to the technical field of time-of-flight measurement systems, and in particular relates to a photon receiving simulation method and electronic device for a time-of-flight measurement system. Background Technology

[0002] A time-of-flight measurement system (TOF) is a measurement system that combines photon detection technology with the principle of time-of-flight measurement. Compared with ranging sensors such as ultrasonic sensors, infrared ranging sensors, and millimeter-wave radar, TOF offers advantages such as high precision, high resolution, strong anti-interference capabilities, and ultra-long detection range. Therefore, TOF is widely used in scenarios such as topographic mapping, environmental monitoring, robot perception, and autonomous navigation.

[0003] During product development, to further understand the performance of the time-of-flight measurement system (TOF) under different complex scenarios and to measure various indicators of the TOF, developers typically need to build simulation models of the TOF. Since the TOF calculates the distance information of a target object by statistically processing photon events over a certain time period, and the process by which photons travel from the emission source, are reflected from the target, and reach the detection array is a random process, the number of photon events occurring on the detection array varies at different times. Therefore, when building the simulation model of the TOF, developers need to simulate the number of photons received by the detection array at each moment, and then determine the number of photon events occurring on the detection array at each moment based on the simulated photon count.

[0004] However, the number of photons received by the detection unit calculated by the existing time-of-flight measurement system photon receiving simulation method differs significantly from the number of photons received under actual operating conditions. Therefore, the accuracy of the existing photon receiving simulation calculation is low. Summary of the Invention

[0005] In view of this, embodiments of this application provide a photon receiving simulation method and electronic device for a time-of-flight measurement system, in order to improve the accuracy of photon receiving simulation calculations.

[0006] A first aspect of this application provides a photon receiving simulation method for a time-of-flight measurement system. The time-of-flight measurement system includes a transmitter and a detector array. The transmitter emits probe light, and the detector array includes multiple detector units. The detector array receives echo light formed by the probe light being reflected from a target object. The method includes:

[0007] For each analysis time within the analysis period, the number of incident photons arriving at the detector array at that analysis time is obtained;

[0008] Based on the number of incident photons and the distribution area of ​​the incident photons, the number of received photons corresponding to each detection unit at the analysis time is obtained;

[0009] Based on the number of received photons for each detection unit at the analysis time and the photon event triggering model, the number of times the photon event corresponding to the detection array is triggered at the analysis time is obtained;

[0010] The number of triggers of photon events corresponding to the detection array within the analysis period is accumulated to obtain the histogram data corresponding to the detection array. The histogram data is used to determine the performance indicators of the detection array.

[0011] This embodiment has the following advantages:

[0012] In this embodiment, the electronic device can determine the number of received photons corresponding to each detection unit by combining the number of incident photons and the distribution area of ​​the incident photons. Since researchers typically design time-of-flight measurement systems with a detector array area larger than the area of ​​the echo light reaching the array, only a portion of the detector array usually receives incident photons during actual operation. Therefore, the method provided in this embodiment allows the calculated distribution of received photons to more closely approximate the actual distribution during operation, thereby making the trigger count of photon events corresponding to the detector array closer to the actual count, thus improving the accuracy of photon reception simulation calculations and the accuracy of histogram data.

[0013] In one possible implementation of the first aspect, obtaining the number of received photons corresponding to each of the detection units at the analysis time based on the number of incident photons and the distribution area of ​​the incident photons includes:

[0014] Based on the number of incident photons and the spot dispersion, the number of received photons corresponding to the detection array is calculated;

[0015] The number of received photons for each detection unit at the analysis time is obtained based on the number of received photons and the distribution area of ​​the incident photons.

[0016] This embodiment has the following advantages:

[0017] Since the beam divergence reflects the degree of divergence of the probe light, electronic devices can combine the number of incident photons with the beam divergence to calculate the number of received photons, which can more realistically simulate the propagation loss of received photons in space, thereby improving the accuracy of simulation calculations.

[0018] In one possible implementation of the first aspect, the incident photons include echo photons and noise photons, and the received photons include echo received photons and noise received photons. The calculation of the number of received photons corresponding to the detector array based on the number of incident photons and the beam dispersion includes:

[0019] Determine the spot divergence;

[0020] The number of received echo photons is calculated based on the spot divergence, the number of echo photons, and the negative binomial distribution function.

[0021] The number of noise received photons is calculated based on the spot divergence, the number of noise photons, and the negative binomial distribution function.

[0022] This embodiment has the following advantages:

[0023] Electronic devices can perform a negative binomial distribution calculation based on spot divergence to calculate the number of received photons corresponding to the detector array at each analysis time. Since the number of received photons obtained by performing a negative binomial distribution calculation based on spot divergence more closely approximates the number of photons that the detector array can receive under actual operating conditions, the method provided in this embodiment can improve the accuracy of the number of received photons corresponding to the detector array calculated by the time-of-flight measurement system simulation model, thereby improving the accuracy of the simulation results generated by the simulation model.

[0024] In one possible implementation of the first aspect, obtaining the number of received photons corresponding to each detection unit at the analysis time based on the number of received photons and the distribution area of ​​the incident photons includes:

[0025] The echo region where the echo photons are distributed on the detector array and the noise region where the noise photons are distributed on the detector array are obtained.

[0026] Based on the number of echo received photons and the echo region, a first coordinate of each echo received photon on the detection array is randomly generated;

[0027] Based on the number of noisy received photons and the noisy region, a second coordinate of each noisy received photon on the detection array is randomly generated;

[0028] The number of received photons corresponding to each detection unit at the analysis time is obtained based on the first coordinates of all the echo received photons and the second coordinates of all the noise received photons.

[0029] This embodiment has the following advantages:

[0030] Because the echo region on the detection array that can receive echo photons often differs from the noise region that can receive noise photons during actual operation of the time-of-flight measurement system, the electronic equipment generates the first coordinates of the echo photons based on the echo region and the second coordinates of each noise photon based on the noise region. This makes the photon distribution closer to the real detection scenario, reduces the error caused by simplified models (such as the assumption of uniform distribution), and thus improves the accuracy of simulation calculations.

[0031] In one possible implementation of the first aspect, obtaining the number of times the photon event corresponding to the detection array is triggered at the analysis time based on the number of received photons corresponding to each detection unit at the analysis time and the photon event triggering model includes:

[0032] For each detection unit, the triggering state of the photon event on the detection unit is determined based on the number of received photons and the triggering time at the analysis time. The triggering state includes a triggered state and a non-triggered state.

[0033] Based on the triggering state of the photon event on each of the detection units, the number of times the photon event corresponding to the detection array is triggered at the analysis time is obtained.

[0034] This embodiment has the following advantages:

[0035] The method provided in this embodiment allows electronic devices to directly determine whether a photon event has occurred on the detection unit based on the triggering time and triggering state of the detection unit. Compared with the dead-time model in the prior art, the method provided in this embodiment has a smaller computational load, thereby improving the computational efficiency of the simulation model.

[0036] In one possible implementation of the first aspect, obtaining the number of triggering events of the photon event corresponding to the detection array at the analysis time based on the triggering state of the photon event on each of the detection units includes:

[0037] The number of detection units in the triggered state is counted to obtain the number of times the photon event corresponding to the detection array is triggered at the analysis time.

[0038] In one possible implementation of the first aspect, determining the triggering state of the photon event on the detection unit based on the number of received photons corresponding to the detection unit at the analysis time and the triggering time includes:

[0039] If the triggering time is empty and the number of received photons at the analysis time is greater than 0, the triggering state of the photon event on the detection unit is determined to be triggered; or

[0040] If the triggering time is empty and the number of photons received by the detection unit at the analysis time is equal to 0, the triggering state of the photon event on the detection unit is determined to be non-triggered.

[0041] In one possible implementation of the first aspect, determining the triggering state of the photon event on the detection unit based on the number of received photons corresponding to the detection unit at the analysis time and the triggering time includes:

[0042] If the trigger time is not empty, calculate the time difference between the analysis time and the trigger time, wherein the trigger time is earlier than the analysis time;

[0043] If the time difference is greater than or equal to the dead time of the detection unit, and the number of received photons corresponding to the detection unit at the analysis time is greater than 0, the triggering state of the photon event on the detection unit is determined to be a triggered state; or

[0044] If the time difference is greater than or equal to the dead time of the detection unit, and the number of received photons corresponding to the detection unit at the analysis time is equal to 0, the triggering state of the photon event on the detection unit is determined to be a non-triggered state; or

[0045] If the time difference is less than the dead time of the detection unit, the triggering state of the photon event on the detection unit is determined to be a non-triggered state.

[0046] In one possible implementation of the first aspect, after determining the triggering state of the photon event on the detection unit as a triggered state, the method further includes:

[0047] The trigger time of the detection unit is updated based on the analysis time.

[0048] In one possible implementation of the first aspect, obtaining the number of incident photons arriving at the detector array at the analysis time includes:

[0049] The number of incident photons is calculated based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, the third parameter of the probe light, and the fourth parameter of the sunlight. The first parameter includes the optical efficiency of the time-of-flight measurement system, the optical efficiency of the transmitter, the emission power of the transmitter, the photon detection efficiency of the detector array, the atmospheric transmittance, the first receiving area of ​​the detector array, and the distance between the transmitter and the target object. The second parameter includes the reflectivity of the target object and the second receiving area of ​​the target object. The third parameter includes the power of the probe light, the frequency of the probe light, the pulse interval of the probe light, and the divergence angle of the probe light. The fourth parameter includes the solar irradiance, the angle between the sunlight and the normal to the surface of the target object, and the bandwidth of the filter in the time-of-flight measurement system.

[0050] In one possible implementation of the first aspect, the incident photons include echo photon counts and noise photons, and the calculation of the number of incident photons based on a first parameter of the time-of-flight measurement system, a second parameter of the target object, a third parameter of the probe light, and a fourth parameter of sunlight includes:

[0051] The number of echo photons is calculated based on the first parameter, the second parameter, and the third parameter;

[0052] The number of noise photons is calculated based on the first parameter, the second parameter, and the fourth parameter.

[0053] A second aspect of this application provides a photon receiving simulation device for a time-of-flight measurement system. The time-of-flight measurement system includes a transmitter and a detector array. The transmitter emits probe light, and the detector array includes multiple detector units. The detector array receives echo light formed by the probe light reflected from a target object. The device includes:

[0054] An incident photon acquisition module is used to acquire the number of incident photons arriving at the detector array at each analysis time within the analysis period.

[0055] A photon count determination module is used to determine the number of received photons corresponding to each detection unit at the analysis time based on the number of incident photons and the distribution area of ​​the incident photons.

[0056] The trigger count determination module is used to determine the trigger count of the photon event corresponding to the detection array at the analysis time based on the number of received photons corresponding to each detection unit at the analysis time and the photon event triggering model;

[0057] The histogram generation module is used to accumulate the number of triggers of photon events corresponding to the detection array within the analysis period to obtain histogram data corresponding to the detection array. The histogram data is used to determine the performance indicators of the detection array.

[0058] A third aspect of this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the photon receiving simulation method for the time-of-flight measurement system as described in the first aspect above.

[0059] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the photon receiving simulation method for the time-of-flight measurement system as described in the first aspect above.

[0060] A fifth aspect of this application provides a computer program product that, when run on a computer, causes the computer to execute the photon receiving simulation method for the time-of-flight measurement system described in the first aspect. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0062] Figure 1 This is a schematic diagram of the triggering mechanism of a single-photon avalanche photodiode provided in an embodiment of this application;

[0063] Figure 2 This is a flowchart of a photon receiving simulation method for a time-of-flight measurement system provided in an embodiment of this application;

[0064] Figure 3 This is a schematic diagram of the simulation process of a time-of-flight measurement system provided in an embodiment of this application;

[0065] Figure 4 This is a schematic diagram of a time-of-flight measurement system receiving noisy photons, provided in an embodiment of this application.

[0066] Figure 5 This is a flowchart of another photon receiving simulation method for a time-of-flight measurement system provided in this application embodiment;

[0067] Figure 6This is a schematic diagram of a calculation process for spot divergence provided in an embodiment of this application;

[0068] Figure 7 This is a schematic diagram illustrating a calculation process for the number of received photons provided in an embodiment of this application;

[0069] Figure 8 This is a schematic diagram of a distribution area and a receiving area provided in an embodiment of this application;

[0070] Figure 9 This is a flowchart of another photon receiving simulation method for a time-of-flight measurement system provided in this application embodiment;

[0071] Figure 10 This application provides a simulation method for a time-of-flight measurement system based on a single-photon avalanche diode.

[0072] Figure 11 This is a schematic diagram of a photon receiving simulation device for a time-of-flight measurement system provided in an embodiment of this application;

[0073] Figure 12 This is a schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0074] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0075] Time-of-flight (TOF) measurement systems, such as lidar, calculate target distance by measuring the time difference between the emission and reception of probe light. Compared to common measurement systems like ultrasonic sensors, infrared ranging sensors, and millimeter-wave radar, TOF systems offer significant advantages. They not only achieve high-precision measurements, accurately capturing target details and delivering high-resolution imaging, but also possess strong anti-interference capabilities, operating stably even in complex environments. Furthermore, TOF systems have a longer detection range, meeting the needs of large-scale monitoring. Given these outstanding characteristics, in the field of topographic mapping, TOF systems can be used to create high-precision maps, providing reliable data for urban planning and geological research; in the field of environmental monitoring, TOF systems can accurately detect the distribution of air pollutants and monitor changes in vegetation cover; and in the field of robot perception and autonomous navigation, TOF systems help robots perceive their surroundings in real time, achieving precise positioning and path planning.

[0076] A simulation model of a time-of-flight (TOF) measurement system is a computer program that simulates the system's working principles, performance, and behavior under different environments. Using this simulation model, researchers can simulate the propagation trajectory of photons after emission in various environments, as well as the reflection of photons on the surfaces of various targets. Furthermore, by changing parameters in the simulation model, such as the sensitivity of the photon detector and the emission frequency of the probe light, researchers can quickly test the performance of the TOF measurement system under different settings, thereby optimizing the system design and improving its ranging accuracy and stability. Therefore, by establishing a simulation model of the TOF measurement system, researchers can gain a deeper understanding of its working principles and performance during the development process and before actual application.

[0077] Among numerous time-of-flight (TOF) measurement systems, those based on photon detection counting are widely popular due to their longer ranging range and stronger echo detection capabilities. A TOF system based on photon detection counting utilizes a photon detector to count the echo photons of a probe light pulse, thereby acquiring target information. Common TOF systems based on photon detection counting include those based on single-photon avalanche photodiodes (SPADs), photomultiplier tubes (PMTs), silicon photomultiplier tubes (SiPMs), and avalanche photodiodes (APDs).

[0078] In practical devices, to ensure the reliability of the time-of-flight measurement system (TOF) when receiving echoes, the surface area of ​​the detection array is often larger than the area of ​​the echo. Therefore, during the actual operation of the TOF system, only a portion of the detection array can receive incident photons. However, existing photon reception simulation methods for TOF systems based on photon detection counting do not incorporate the distribution area of ​​incident photons on the detection array. Consequently, simulations using existing techniques are prone to discrepancies between the calculated number of received photons for each detection unit on the array and the actual operating conditions. This leads to discrepancies between the simulated histogram data and the actual operating conditions, resulting in lower accuracy of the simulation results.

[0079] Therefore, in this embodiment of the application, the electronic device can calculate and analyze the number of received photons corresponding to each detection unit at a given time based on the distribution area of ​​incident photons on the detection array. Thus, the method provided in this embodiment of the application can make the distribution of the calculated number of received photons closer to the actual distribution during operation, thereby making the number of triggers of photon events corresponding to the detection array closer to the actual number of triggers during operation, thereby improving the accuracy of photon reception simulation and the accuracy of histogram data.

[0080] Furthermore, since the time-of-flight measurement system based on photon detection and counting is a time-of-flight measurement system that detects and counts the echo photons reflected back from the target object to obtain the distance information of the target object, when researchers establish a simulation model of the time-of-flight measurement system based on photon detection and counting, they need to use the Poisson distribution function to simulate the number of photons received by the detection array on the time-of-flight measurement system at each moment, and then determine the number of photon events that occur in the detection array at each moment based on the simulated number of photons.

[0081] However, the Poisson distribution function assumes that each photon reception event is independent and has a constant average occurrence rate. But the scattering and interference of photons in the probe light cause the photon reception events to be correlated, and the occurrence rate of photon reception events is not constant but varies with spatial location. Therefore, approximating the number of received photons using the Poisson distribution function ignores some of the approximation conditions used to describe the speckle phenomenon of the probe light, resulting in low accuracy of the photon count simulated by the Poisson distribution function.

[0082] Therefore, this application provides a simulation method for performing a negative binomial distribution operation based on the number of incident photons and the speckle dispersion. In the method provided by this application, an electronic device can perform a negative binomial distribution operation based on the number of incident photons and the speckle dispersion to calculate the number of photons received by the detector array at each analysis time. Since the negative binomial distribution function can reflect the correlation between photon reception events, it meets relevant approximation conditions when describing the speckle phenomenon of the detector light. Furthermore, the mixed distribution characteristics of the negative binomial distribution function are more consistent with the physical mechanism of detector light speckle formation; therefore, simulating the number of received photons for each detector unit at the analysis time using the negative binomial distribution operation yields more accurate simulation results. This method can be applied to the simulation model of any time-of-flight measurement system, such as the time-of-flight measurement system based on single-photon avalanche photodiode, the time-of-flight measurement system based on photomultiplier tube, the time-of-flight measurement system based on silicon photomultiplier tube, and the time-of-flight measurement system based on avalanche photodiode. In other words, the method provided in this application embodiment can be applied to any time-of-flight measurement system simulation model that needs to simulate the number of photons received by the detection unit during the simulation process.

[0083] Among numerous time-of-flight measurement systems based on photon detection counting, those based on single-photon avalanche photodiodes (SPADs) exhibit outstanding long-range detection capabilities. Therefore, SPAD-based SPAD systems have become the mainstay of vehicle-mounted radar and robotic sensing detectors, and a key focus of simulation research. Furthermore, since SPAD-based SPAD systems belong to the category of photon detection counting-based SPAD systems, simulation calculations for SPAD-based SPAD systems also require calculating the number of received photons for each detection unit at the analysis time using negative binomial distribution operations. In other words, the simulation method based on negative binomial distribution operations described above can also be applied to simulation models based on negative binomial distribution operations.

[0084] However, unlike other time-of-flight measurement systems, the time-of-flight measurement system based on single-photon avalanche photodiodes has a dead time characteristic. Therefore, during the simulation of the time-of-flight measurement system based on single-photon avalanche photodiodes, it is necessary to further combine the number of received photons with the dead time of the detection unit to determine the number of times the photon event is triggered. Figure 1 A schematic diagram illustrating the triggering mechanism of a single-photon avalanche photodiode provided in an embodiment of this application is shown. Figure 1As shown, a single-photon avalanche photodiode (SPAD) triggers a photon event after receiving a photon at time T1. Subsequently, the SPAD undergoes a quenching process and a recovery process. During the quenching and recovery processes, the SPAD cannot trigger a photon event again; therefore, the duration of the quenching and recovery processes can be called the dead time of the SPAD. Since the SPAD will not trigger a photon event even if it receives another photon during the dead time, the photon arriving at time T2 will not trigger a photon event. When a photon arrives at the SPAD at time T3, because the time difference between time T3 and T1 is greater than the dead time, the photon arriving at time T3 will trigger a photon event again.

[0085] Because single-photon avalanche photodiodes (SPADs) have a dead time characteristic, existing simulation models of time-of-flight measurement systems based on SPADs often require complex triggering models to simulate the dead time characteristics of SPADs, thus increasing the computational load and processing time of the simulation model.

[0086] Therefore, this application provides a photon event triggering model. Using the photon event triggering model provided in this embodiment, after the electronic device obtains the number of photons received by each detection unit at the analysis time through negative binomial distribution calculation, it can update the triggering state of the corresponding detection unit according to the triggering time and the number of photons received by each detection unit at the current analysis time. Then, the electronic device can determine the number of photon event triggers of the detection array at the current analysis time based on the triggering states of all detection units. With the method provided in this embodiment, the electronic device does not need to perform a large number of complex calculations; instead, it can determine the triggering state of the detection unit and thus the number of photon event triggers by simply comparing the triggering time and the number of photons received by each detection unit. Therefore, the method provided in this embodiment can simplify the calculation of the time-of-flight measurement system simulation model, reduce the computational load and time of the time-of-flight measurement system simulation model, and thus improve computational efficiency.

[0087] The technical solution of this application will be described below through specific embodiments.

[0088] Reference Figure 2This document illustrates a flowchart of a photon receiving simulation method for a time-of-flight measurement system provided in an embodiment of this application. The time-of-flight measurement system may include a transmitter and a detector array. The transmitter in the time-of-flight measurement system can be used to emit probe light. The detector array in the time-of-flight measurement system may include multiple detector units for receiving the echo light formed by the reflection of the probe light from a target object. This method can be applied to any electronic device capable of simulating a time-of-flight measurement system, such as a computer, mobile phone, tablet computer, or server. The photon receiving simulation method for the aforementioned time-of-flight measurement system may specifically include the following steps:

[0089] S201. For each analysis time within the analysis period, obtain the number of incident photons arriving at the detector array at that analysis time.

[0090] In this embodiment, when a user needs to perform simulation calculations on the time-of-flight measurement system using a simulation model, the user can initiate a simulation command to the electronic device. The electronic device can respond to the simulation command and, for each analysis moment within the analysis period, obtain the number of incident photons arriving at the detector array at each analysis moment. Here, the analysis period can be the duration during which the time-of-flight measurement system can receive photons during the photon reception simulation calculation, and the analysis moment can be any moment within the analysis period.

[0091] In one possible implementation, when researchers need to specifically configure the time-of-flight measurement system or application environment for the simulation calculation, the simulation instructions may include, but are not limited to, parameters such as the first parameter corresponding to the time-of-flight measurement system, the second parameter of the target object, the third parameter of the probe light, and the fourth parameter corresponding to sunlight. The electronic device can respond to the simulation instructions and, for any analysis moment in the analysis cycle, calculate the number of incident photons arriving at the detection array at that analysis moment based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, the third parameter of the probe light, and the fourth parameter of sunlight.

[0092] Specifically, the first parameter corresponding to the time-of-flight measurement system can be a parameter representing the optical performance of the time-of-flight measurement system currently being simulated. Specifically, the first parameter can include at least one of the following: the optical efficiency of the time-of-flight measurement system, the optical efficiency of the transmitter in the time-of-flight measurement system, the emission power of the transmitter in the time-of-flight measurement system, the photon detection efficiency of the detector array in the time-of-flight measurement system, atmospheric transmittance, the first receiving area of ​​the detector array in the time-of-flight measurement system, and the distance between the transmitter and the target object. The first receiving area can be the area corresponding to the echo region where echo photons are distributed on the detector array. The second parameter of the target object can be a parameter describing the characteristics of the target object when interacting with light. Specifically, the second parameter can include at least one of the second receiving area on the target object capable of receiving the probe light and the reflectivity of the target object. The third parameter of the probe light can be a parameter describing a certain characteristic of the probe light emitted by the time-of-flight measurement system. Specifically, the third parameter of the probe light can include at least one of the probe light power, the probe light frequency, the probe light pulse interval, and the probe light divergence angle. The fourth parameter corresponding to sunlight can be a parameter representing the characteristics of sunlight. Specifically, the fourth parameter may include at least one of the following: solar irradiance, the angle between sunlight and the normal to the surface of the target object, and the bandwidth of the filter in the time-of-flight measurement system.

[0093] In one possible implementation, since the actual operating environment of the time-of-flight measurement system often includes not only probe light but also sunlight, the photons arriving at the probe array of the time-of-flight measurement system can include echo photons from the probe light and noise photons from the sunlight. Therefore, the incident photons arriving at the probe array can include echo photons and noise photons. In view of this, the number of incident photons arriving at the probe array at the analysis time can include the number of echo photons and the number of noise photons. Specifically, for any analysis time in the analysis cycle, the electronic equipment can first calculate the number of echo photons arriving at the probe array at that analysis time based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, and the third parameter of the probe light. The electronic equipment can also calculate the number of noise photons arriving at the probe array at that analysis time based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, and the fourth parameter of the sunlight.

[0094] In one possible implementation, the electronic device can calculate the number of echo photons arriving at the detector array at each analysis time based on the first parameter of the time-of-flight measurement system, the second parameter of the target, and the third parameter of the probe light.

[0095] Specifically, Figure 3 A schematic diagram illustrating the simulation process of a time-of-flight measurement system provided in an embodiment of this application is shown. Figure 3 As shown, a time-of-flight measurement system may include a transmitter and a detector array. Figure 3 As shown in (a), in response to simulation commands, the transmitter can emit a probe beam toward the target. The divergence angle of the probe beam can be expressed as θ. t The solid angle of the probe light can be expressed as Ω. t The second receiving area on the target object that can receive the probe light can be represented as A. g The distance between the target and the transmitter can be represented by R, and the area that the probe light can cover when it reaches the plane where the target is located can be represented by A. t Specifically, the solid angle can be calculated from the divergence angle, i.e., Ω. t =πθ t 2 The divergence angle is the angle between the central axis of the beam and its edge. The solid angle is a solid angle formed when the generatrix of the cone formed by the beams coincides with the boundary of the beam, centered at the apex of the cone. It describes the angular range occupied by the beam in space. Both the divergence angle and the solid angle correspond to areas that increase with the beam's propagation distance.

[0096] In the time domain, the energy of the probe light emitted by the transmitter can be determined based on the maximum width w of the probe light. t The light energy exhibits a Gaussian distribution, therefore the standard deviation of the detected light energy can be: The equation for the change of probe light intensity over time can be: Where I(t) represents the intensity of the probe light; t represents the analysis time and is the independent variable; t0 represents the start time of the analysis period; I0 represents the initial value of the probe light intensity; σ represents the standard deviation of the probe light energy; and exp represents an exponential function. The power of the probe light emitted by the transmitter when it reaches the target can be expressed as P. g ;where P g =P t η t η a A g / A t P t η can represent the power of the probe light emitted by the transmitter. t The optical efficiency η of the transmitter of the time-of-flight measurement system a For the optical efficiency of the time-of-flight measurement system, A g A can be the second receiving area on the target object that can receive the probe light. t It can be defined as the area that the probe light can cover when it reaches the plane where the target object is located.

[0097] like Figure 3As shown in (b), after receiving the probe light, the target object reflects the probe light back to the time-of-flight measurement system. At this time, the detection array on the time-of-flight measurement system can begin to receive the echo reflected by the target object. Figure 3 As shown in (b), the solid angle of the echo can be expressed as Ω. r The area of ​​the echo on the detector array can be represented as A. r A r This represents the area corresponding to the echo region where the echo photons are distributed on the detector array.

[0098] Therefore, when the target object is a standard Lambertian reflector, the electronic device can calculate the expected number of echo photons arriving at the detector array at each analysis time by combining the area corresponding to the echo region on the detector array and the second receiving area on the target object capable of receiving the detector light. Specifically, for any analysis time in the analysis period, the expected number of echo photons arriving at the detector array can be calculated by the electronic device based on the optical efficiency of the transmitter of the time-of-flight measurement system, the optical efficiency of the time-of-flight measurement system, the atmospheric transmittance, the photon detection efficiency of the detector array on the time-of-flight measurement system, the first receiving area corresponding to the detector array, the pulse interval of the detector light emitted by the transmitter, the power of the detector light, the frequency of the detector light, the divergence angle of the detector light, the second receiving area on the target object capable of receiving the detector light, and the reflectivity of the target object. The specific formula for calculating the number of echo photons arriving at the detector array at any analysis time can be as follows:

[0099]

[0100] Where, N s This can represent the number of echo photons arriving at the detector array at any given analysis time. Δt can be the pulse interval of the probe light. t It can be used to detect the power of light. η t This can be used to measure the optical efficiency of the transmitter in a time-of-flight measurement system. η r This can be used to determine the optical efficiency of a time-of-flight measurement system. η q This can be used to determine the photon detection efficiency of the detection array on a time-of-flight measurement system. η a It can be considered as atmospheric transmittance. A g This can be the second receiving area corresponding to the region on the target object that can receive the probe light. ρ can be the reflectivity of the target object. A r θ can be the first receiving area of ​​the detector array, where the first receiving area corresponds to the area of ​​the echo region on the detector array where the echo photons are distributed. h can be Planck's constant. v can be the frequency of the probe light. t R can be the divergence angle of the probe light. R can be the distance between the target and the transmitter on the time-of-flight measurement system.

[0101] In one possible implementation, the electronic device can calculate the number of noise photons arriving at the detector array at each analysis time based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, and the fourth parameter of sunlight.

[0102] Specifically, Figure 4 This diagram illustrates a time-of-flight measurement system receiving noisy photons, as provided in an embodiment of this application. When sunlight shines on a target object, the target object also reflects sunlight onto the detection array of the time-of-flight measurement system. Therefore, the photons received by the detection array include not only the echo photons of the probe light but also the noise photons of the sunlight reflected by the target object. Figure 4 As shown, the angle between sunlight and the normal to the surface of the target object can be expressed as θ. s The area of ​​the target object that can receive sunlight can be represented as A. s .

[0103] Specifically, for a given analysis time, the expected number of noise photons arriving at the detector array can be calculated by the electronic equipment based on the solar irradiance, the atmospheric transmittance of the time-of-flight measurement system, the photon detection efficiency of the detector array on the time-of-flight measurement system, the second receiving area of ​​the target object receiving the detector light, the angle between the sunlight and the normal to the target object surface, the solar irradiance, and the bandwidth of the filter in the time-of-flight measurement system. The specific formula for calculating the number of noise photons arriving at the detector array at any given analysis time can be as follows:

[0104]

[0105] Where, N b P can represent the number of noise photons arriving at the detector array at any given analysis time. λ Δt can be the solar irradiance. Δt can be the pulse interval of the probe light emitted by the transmitter. Δλ can be the bandwidth of the filter in the time-of-flight measurement system. ρ can be the reflectivity of the target object. θ s It can be the angle between sunlight and the normal to the surface of the target object. η r This can be used to determine the optical efficiency of a time-of-flight measurement system. η q This can be used to improve the photon detection efficiency of the detection array. η a It can be considered as atmospheric transmittance. A g This can be a second receiving area for the target object to receive the probe light. A r...

[0106] S202. Based on the number of incident photons and the distribution area of ​​the incident photons, the number of received photons corresponding to each detection unit at the analysis time is obtained.

[0107] In this embodiment, the simulation command initiated by the user may include at least the distribution area of ​​incident photons. This distribution area can represent the region on the detector array that the time-of-flight measurement system currently being simulated can receive incident photons during actual operation. After determining the number of incident photons arriving at the detector array at each analysis time, the electronic device can determine the number of photons received by each detector unit at the analysis time based on the number of incident photons in the detector array and the distribution area of ​​incident photons set by the user in the simulation command.

[0108] In one possible implementation, the incident photons can include echo photons and noise photons. The distribution area can include the echo region where echo photons are distributed on the detector array and the noise region where noise photons are distributed on the detector array. Specifically, the distribution area of ​​echo photons on the detector array can be determined by the user based on experience from the actual operation of the time-of-flight measurement system, or it can be set by the user based on current simulation requirements. In the design of the time-of-flight measurement system, in order for the detector array of the time-of-flight measurement system to effectively receive the detection light signal reflected by the target, the detector array is usually designed with a large field of view and a wide spectral response optical system. However, the reflection characteristics of the target object to sunlight are diverse, and coupled with atmospheric scattering, the entire surface of the detector array may receive sunlight reflected by the target object. Therefore, the noise region where noise photons are distributed on the detector array can be the entire receiving area of ​​the detector array.

[0109] S203. Based on the number of received photons for each detection unit at the analysis time and the photon event triggering model, obtain the number of times the photon event corresponding to the detection array is triggered at the analysis time.

[0110] In this embodiment, after calculating the number of received photons corresponding to each detection unit on the detection array at a certain analysis time, the electronic device can input the number of received photons corresponding to each detection unit into the photon event triggering model, so as to determine the number of times the photon event of the detection array is triggered at that analysis time through the photon event triggering model.

[0111] Specifically, the photon event triggering model can determine whether a detection unit can trigger a photon event based on the triggering time corresponding to each detection unit. Then, for detection units that can trigger a photon event and receive a greater than zero number of photons, the model updates the triggering state of that detection unit to a triggered state. The triggered state indicates that the detection unit has triggered a photon event at the current analysis time. For detection units that cannot trigger a photon event or receive zero photons, the model updates their triggering state to a non-triggered state. The non-triggered state indicates that the detection unit has not triggered a photon event at the current analysis time. Then, the model can determine the number of photon event triggers at the current analysis time based on the number of detection units in the triggered state.

[0112] S204. Accumulate the number of triggers of photon events corresponding to the detector array within the analysis period to obtain the histogram data corresponding to the detector array.

[0113] In this embodiment, after determining the number of times the photon events of the detector array are triggered at each analysis time, the electronic device can accumulate the number of times the photon events are triggered at each analysis time within the analysis period to determine the histogram data of the detector array within the analysis period.

[0114] The method provided in this embodiment addresses the issue that, during actual operation of the time-of-flight measurement system, only a portion of the detector array receives incident photons. Therefore, by calculating the number of received photons for each detector unit based on the distribution area of ​​the incident photons, the simulated number of received photons more closely reflects actual operating conditions. Thus, the method provided in this embodiment improves the accuracy of the incident photon distribution during simulation, thereby enhancing the realism of the simulation results.

[0115] In one possible implementation, after generating histogram data, the electronic device can perform target detection and recognition based on the distribution of photon events in the histogram data, generating target detection results (such as whether a target exists in the scene, the target's detection reflectivity, the target's detection distance, and the detection location). Then, the electronic device can compare and analyze the target detection results with the target information input by the user during simulation (such as the target's fourth parameter, the distance between the target and the time-of-flight measurement system set in the simulation model, etc.) to determine the performance indicators of the time-of-flight measurement system currently performing the simulation. For example, the electronic device can determine the performance indicators of the time-of-flight measurement system currently performing the simulation based on the difference between the target's detection distance and the distance between the target and the time-of-flight measurement system set in the simulation model.

[0116] Figure 5 A flowchart illustrating the specific implementation of a photon receiving simulation method S202 for a time-of-flight measurement system according to the second embodiment of this application is shown. See also... Figure 5 Compared to Figure 2 In the embodiment provided, S202 of the photon receiving simulation method for a time-of-flight measurement system includes: S2021 to S2022, which are detailed below:

[0117] S2021. Based on the number of incident photons and the spot dispersion, calculate the number of received photons corresponding to the detector array.

[0118] In this embodiment, for any analysis time in the analysis cycle, after determining the number of incident photons for that analysis time, the electronic device can calculate the number of received photons received by the detection array at that analysis time based on the number of incident photons and the spot dispersion at that analysis time.

[0119] In one possible implementation, the incident photons may include echo photons and noise photons; therefore, the number of incident photons may include the number of echo photons and the number of noise photons. The received photons received by the detector array may include echo received photons and noise received photons; therefore, the number of received photons received by the detector array at any given analysis time may include the number of echo received photons and the number of noise received photons. Given this, the electronic device can acquire the beam dispersion and calculate the number of echo received photons based on the beam dispersion, the number of echo photons, and the negative binomial distribution function. The electronic device can also calculate the number of noise received photons based on the beam dispersion, the number of noise photons, and the negative binomial distribution function.

[0120] In one possible implementation, the negative binomial distribution function in the electronic device may include a first negative binomial distribution function for calculating the number of echo received photons corresponding to echo photons, and a second negative binomial distribution function for calculating the number of noise received photons corresponding to noise photons.

[0121] After targeting the object, the electronic device can input the desired echo photon count and spot dispersion into the first negative binomial distribution function to calculate the number of echo received photons arriving at the detector array at that analysis time. Then, the electronic device can input the desired noise photon count and spot dispersion into the second negative binomial distribution function to calculate the number of noise received photons arriving at the detector array at that analysis time.

[0122] Specifically, the first negative binomial distribution function can be shown as follows:

[0123]

[0124] Where nbinrnd can represent the negative binomial distribution function. s This can represent the number of photons received in the echo. M d It can represent the beam divergence. N s It can represent the number of echo photons arriving at the detector array at the current analysis time.

[0125] Specifically, the second negative binomial distribution function can be shown as follows:

[0126]

[0127] Where, n b This can represent the number of photons received in noise. N b It can represent the number of noise photons arriving at the detector array at the current analysis time.

[0128] In one possible implementation, the speckle divergence can be obtained by researchers conducting tests on at least three test objects with different reflectivities using a pre-produced time-of-flight measurement system before initiating the simulation command. Specifically, Figure 6 A schematic diagram illustrating a calculation process for spot divergence provided in an embodiment of this application is shown. Figure 6 As shown, researchers can use a time-of-flight measurement system with known parameters to emit probe light towards at least three test objects with different reflectivities and measure the photon count distribution histogram for each test object. The time-of-flight measurement system can transmit the measured photon count distribution histograms to an electronic device, which can determine the peak photon count for each test object based on the histograms. Then, the electronic device can construct a spot divergence function based on the reflectivity and peak photon count of any two test objects. Subsequently, the electronic device can solve for at least two different spot divergence functions based on a pre-defined divergence and photon count range set by the researchers, determine the intersection points within the divergence and photon count ranges, and define the divergence value corresponding to the intersection point as the spot divergence in the negative binomial distribution function.

[0129] The spot divergence function can be specifically described as follows:

[0130]

[0131] The spot divergence function can be a bivariate nonlinear function with two independent variables. f(n0, M0) can be a spot divergence function constructed based on the reflectivity and peak photon number of the i-th test object and the j-th test object. n0 can represent the photon number and is one of the independent variables in the spot divergence function. M0 can represent the divergence value and is the other independent variable in the spot divergence function. iThis can be the peak photon number corresponding to the i-th test object. ρ i C can be the reflectance corresponding to the i-th test object. j This can be the peak photon number corresponding to the j-th test object. ρ j This can be the reflectance corresponding to the j-th test object.

[0132] For example, when the number of test objects is 3, the electronic device can solve the following formulas simultaneously to calculate the spot divergence in the negative binomial distribution function.

[0133]

[0134] Where f1(n0,M0) represents the beam divergence function constructed based on the reflectivity and peak photon number of the first test object, and the reflectivity and peak photon number of the second test object. C1 represents the peak photon number of the first test object. ρ1 represents the reflectivity of the first test object. C2 represents the peak photon number of the second test object. ρ2 represents the reflectivity of the second test object. f2(n0,M0) represents the beam divergence function constructed based on the reflectivity and peak photon number of the second test object, and the reflectivity and peak photon number of the third test object. C3 represents the peak photon number of the third test object. ρ3 represents the reflectivity of the third test object.

[0135] The method provided in this embodiment simplifies the calculation of spot divergence by using the reflectivity and photon number peak values ​​of at least three test objects, thus reducing the computation time required for the electronic device to calculate spot divergence and improving the computational efficiency when calculating spot divergence.

[0136] S2022. Based on the number of received photons and the distribution area of ​​the incident photons, the number of received photons corresponding to each detection unit at the analysis time is obtained.

[0137] In this embodiment, after calculating the number of received photons arriving at the detector array at a certain analysis time, the electronic device can calculate the number of received photons corresponding to each detector unit at the analysis time based on the number of received photons and the distribution area of ​​the incident photons.

[0138] In this embodiment, since the beam divergence can reflect the degree of divergence of the probe light, the electronic device can calculate the number of received photons by combining the number of incident photons with the beam divergence. This can more realistically simulate the propagation loss of received photons in space, thereby improving the accuracy of the simulation calculation.

[0139] Furthermore, in this embodiment, the electronic device can also perform a negative binomial distribution operation based on the spot divergence to calculate the number of received photons corresponding to the detector array at each analysis time. Since the number of received photons obtained through the negative binomial distribution operation is closer to the number of photons that the detector array can receive under actual operating conditions, the method provided in this embodiment can improve the accuracy of the number of received photons corresponding to the detector array calculated by the time-of-flight measurement system simulation model, thereby improving the accuracy of the simulation results generated by the simulation model.

[0140] In one possible implementation, the number of received photons received by the detector array at any given analysis time may include the number of echo received photons and the number of noise received photons. For any analysis time in the analysis period, after determining the number of echo received photons at that analysis time, the electronic device can acquire the echo region where the echo photons are distributed on the detector array, and randomly generate a first coordinate for each echo received photon on the detector array based on the number of echo received photons and the echo region. For any analysis time in the analysis period, after determining the number of noise received photons at that analysis time, the electronic device can acquire the noise region where the noise photons are distributed on the detector array, and randomly generate a second coordinate for each noise received photon on the detector array based on the number of noise received photons and the noise region. Then, for any analysis time in the analysis period, the electronic device can obtain the number of received photons corresponding to each detector unit at that analysis time based on the first coordinates of all echo received photons and the second coordinates of all noise received photons.

[0141] In actual operation, the echo region on the detection array that can receive echo photons often differs from the noise region that can receive noise photons. Therefore, in this embodiment, the electronic device generates the first coordinates of the echo photons based on the echo region and the second coordinates of each noise photon based on the noise region. This makes the photon distribution closer to the real detection scenario, reduces errors caused by simplified models (such as uniform distribution assumptions), and thus improves the accuracy of simulation calculations.

[0142] Figure 7 A schematic diagram illustrating a calculation process for the number of received photons provided in an embodiment of this application is shown. Figure 7 As shown, after calculating the number of echo photons arriving at the detector array at a given analysis time, the electronic device can randomly generate multiple first coordinates based on the number of echo photons and the echo region where the echo photons are distributed on the detector array. These first coordinates can represent the positions of the echo photons when they arrive at the detector array. The number of first coordinates generated by the electronic device at a given analysis time can be equal to the number of echo photons corresponding to that analysis time, and all first coordinates can be located within the echo region.

[0143] After calculating the number of noisy photons arriving at the detector array at a given analysis time, the electronic device can randomly generate multiple second coordinates based on the noise region where the noisy photons are distributed on the detector array. Specifically, the noise region where the noisy photons are distributed on the detector array can be equal to the receiving region of the detector array, while the echo region where the echo photons are distributed on the detector array can be smaller than the receiving region of the detector array. The second coordinates can be used to represent the position of the noisy photons when they arrive at the detector array. The number of second coordinates generated by the electronic device at a given analysis time can be equal to the number of noisy photons corresponding to that analysis time.

[0144] like Figure 7 As shown, one coordinate point on the detector array corresponds to one detector unit. After determining the first coordinate corresponding to each echo photon and the second coordinate corresponding to each noise photon, the electronic device can determine the number of received photons corresponding to the detector unit based on the first and second coordinates.

[0145] In one possible implementation, after determining the number of echo photons received at a given analysis time, the electronic device can input the number of echo photons received, the range of x-coordinate values ​​corresponding to the echo region, and the range of y-coordinate values ​​corresponding to the echo region into a first random function to generate multiple first coordinates. After determining the number of noisy photons received at a given analysis time, the electronic device can also input the number of noisy photons received, the range of x-coordinate values ​​corresponding to the noise region, and the range of y-coordinate values ​​corresponding to the noise region into a second random function to generate multiple second coordinates. The first and second random functions can be Monte Carlo algorithms.

[0146] The first random function can also be one of the following functions.

[0147]

[0148] Here, x1 can represent the x-coordinate value in the first coordinate system. y1 can represent the y-coordinate value in the first coordinate system. randi can represent a random function. 1min It can represent the minimum x-coordinate value within the range of x-coordinate values ​​corresponding to the echo region. 1max This can represent the maximum x-coordinate value within the range of x-coordinate values ​​corresponding to the echo region. 1min This can represent the minimum value of the ordinate within the range of values ​​corresponding to the echo region. 1max It can represent the maximum value of the ordinate within the range of values ​​corresponding to the echo region. sThis can represent the number of photons received in the echo. For example, when the distribution area of ​​the echo photons is [m,n], and the receiving area of ​​the detector array is [M,N], where... At that time, x 1min It can be 1, x 1max It can be m, y 1min It can be 1, y 1max It can be n.

[0149] The second random function can also be one of the following functions.

[0150]

[0151] Where x2 represents the x-coordinate value in the second coordinate system, and y2 represents the y-coordinate value in the second coordinate system. 2min It can represent the minimum x-coordinate value within the range of x-coordinate values ​​corresponding to the noise region. 2max This can represent the maximum x-coordinate value within the range of x-coordinate values ​​corresponding to the noise region. 2min This can represent the minimum value of the ordinate within the range of values ​​corresponding to the noise region. 2max It can represent the maximum value of the ordinate within the range of values ​​corresponding to the noise region. b It can represent the number of photons received by noise.

[0152] Figure 8 A schematic diagram of a distribution area and a receiving area provided in an embodiment of this application is shown. For example... Figure 8 As shown, region 81 in the figure can represent the receiving region of the detector array, which can be [M, N]. Since all regions on the detector array may receive noise photons, the noise photons can reach any position in the receiving region, meaning the noise region can be equal to the receiving region of the detector array. Region 82 in the figure can represent the region on the detector array that can receive echo photons, i.e., the echo region where the echo photons are distributed on the detector array, which can be [m, n]. Since the receiving region of the detector array is usually larger than the echo region, therefore... This shows that, Figure 8 In the probe array shown, x in the first random function 2min It can be 1, x 2max M can be the second random function y. 2min It can be 1, y 2max It can be N.

[0153] Figure 9 A flowchart illustrating the specific implementation of S203 of a photon receiving simulation method for a time-of-flight measurement system according to a third embodiment of this application is shown. See also... Figure 9 Compared to Figure 2In the embodiment provided, S203 of the photon receiving simulation method for a time-of-flight measurement system includes: S2031 to S2032, which are detailed below:

[0154] S2031. For each detection unit, the triggering state of the photon event on the detection unit is determined based on the number of photons received by the detection unit at the analysis time and the triggering time.

[0155] In this embodiment, at any given analysis time, for any detector unit on the detector array, after calculating the number of photons received by that detector unit at that analysis time, the electronic device can determine the triggering state of the photon event on that detector unit based on the triggering time corresponding to that detector unit and the number of photons received. The triggering time corresponding to a particular detector unit can be the time of the most recent triggering of a photon event on that detector unit. The triggering state corresponding to a detector unit can be used to indicate whether a photon event has been triggered on the detector unit. The triggering state of a detector unit can include a triggered state and a non-triggered state.

[0156] In one possible implementation, the electronic device determines the triggering state of the photon event based on the number of received photons and the triggering time, which can specifically include the following two cases:

[0157] Case 1: The trigger time is empty.

[0158] At any given analysis time, for any detector unit on the detector array, if the electronic device determines that the trigger time corresponding to the detector unit is empty, that is, the detector unit has not triggered a photon event during the current simulation, the electronic device can further determine whether the number of photons received by the detector unit at the current analysis time is greater than 0.

[0159] If the trigger time corresponding to the detection unit is empty, and the number of photons received by the detection unit at the analysis time is greater than 0, the electronic device can determine the trigger state of the photon event on the detection unit as triggered, and update the corresponding trigger time of the detection unit according to the current analysis time.

[0160] At any given analysis time, for any detector unit on the detector array, if the trigger time is empty and the number of photons received by the detector unit at that analysis time is equal to 0, the electronic device can determine the trigger state of the photon event on the detector unit as a non-triggered state.

[0161] Case 2: The trigger time is not empty.

[0162] At any given analysis time, for any detector unit on the detector array, if the electronic device determines that the trigger time corresponding to that detector unit is not empty (meaning that the detector unit has already triggered a photon event during the current simulation), since a single-photon avalanche photodiode undergoes a quenching and recovery process after triggering a photon event, it cannot trigger a photon event again during these processes. The duration of the quenching and recovery processes can be referred to as the dead time. Therefore, when the trigger time corresponding to the detector unit is not empty, the electronic device can calculate the time difference between the current analysis time and the trigger time corresponding to that detector unit. The trigger time corresponding to the detector unit can be earlier than the analysis time.

[0163] If the time difference corresponding to the detection unit is greater than or equal to the dead time of the detection unit, and the number of received photons corresponding to the detection unit is greater than 0, the electronic device can determine the triggering state of the photon event on the detection unit as the triggered state, and update the corresponding triggering time of the detection unit according to the current analysis time.

[0164] If the time difference corresponding to the detection unit is greater than or equal to the dead time of the detection unit, and the number of received photons corresponding to the detection unit is equal to 0, the electronic device can determine the triggering state of the photon event on the detection unit as the non-triggered state.

[0165] If the time difference corresponding to the detection unit is less than the dead time of the detection unit, the electronic device can determine the triggering state of the photon event on the detection unit as the non-triggered state.

[0166] In one possible implementation, the trigger time can be stored as a time matrix. Alternatively, it can be stored as a time array. Or it can be stored as a time vector. For the trigger state of a photon event on a certain detection unit, the electronic device can store it as a state matrix. The electronic device can also store the trigger state of a photon event on the detection unit through state identifiers, state arrays, state vectors, etc.

[0167] In one possible implementation, when the trigger time is a time matrix used to record the trigger times of photon events, and the trigger state of photon events on the detection unit is represented by a state matrix, at a certain analysis time during the simulation, for any detection unit on the detection array, after determining the number of photons received by that detection unit at the current analysis time, the electronic device can first determine whether the trigger time in the time matrix corresponding to that detection unit is empty. The trigger time in the time matrix is ​​earlier than the current analysis time. The trigger time in the time matrix can include the following two cases:

[0168] Case 1: The trigger time is empty.

[0169] If, when the trigger time is empty, the electronic device determines that the number of photons received by the detection unit at the current analysis time is greater than 0 (i.e., at the current analysis time, the trigger time in the time matrix of the detection unit is empty and the number of received photons is greater than 0), then the electronic device can update the state matrix corresponding to the detection unit to the first state matrix and write the current analysis time as the trigger time into the time matrix corresponding to the detection unit. The first state matrix can be used to represent the detection unit transitioning from a state without a triggered photon event to a state with a triggered photon event. If, when the trigger time is empty, the electronic device determines that the number of photons received by the detection unit at the current analysis time is equal to 0 (i.e., at the current analysis time, the trigger time in the time matrix of the detection unit is empty and the number of received photons is equal to 0), then the electronic device can update the state matrix corresponding to the detection unit to the fourth state matrix. Alternatively, the electronic device can choose not to write the current analysis time as the trigger time into the time matrix corresponding to the detection unit; that is, in this case, the trigger time in the time matrix remains empty. The fourth state matrix can be used to represent the detection unit being in a state without a triggered photon event.

[0170] Case 2: The trigger time is not empty.

[0171] If the trigger time is not empty, the electronic device can calculate the time difference between the current analysis time and the trigger time in the time matrix, and determine whether the time difference is greater than or equal to the dead time corresponding to the detection unit. If the electronic device determines that the time difference is less than the dead time, it can update the state matrix corresponding to the detection unit to the third state matrix, or it can choose not to update the trigger time in the time matrix. The third state matrix represents the state in which the detection unit is in a state where a photon event cannot be triggered.

[0172] If the trigger time is not empty, and the electronic device determines that the time difference is greater than or equal to the dead time, then the electronic device can further determine whether the number of photons received by the detection unit at the current analysis time is greater than 0. If the trigger time is not empty and the time difference is greater than or equal to the dead time, and the electronic device determines that the number of photons received by the detection unit at the current analysis time is greater than 0, then the electronic device can determine that a photon event has been triggered again on the detection unit. At this time, the electronic device can update the state matrix corresponding to the detection unit to the second state matrix, and update the trigger time in the time matrix corresponding to the detection unit according to the current analysis time. The second state matrix can be used to represent the state of the detection unit changing from triggering a photon event to triggering a photon event again. If the trigger time is not empty and the time difference is greater than or equal to the dead time, and the electronic device determines that the number of photons received by the detection unit at the current analysis time is equal to 0, then the electronic device can update the state matrix corresponding to the detection unit to the fourth state matrix, and does not update the time matrix corresponding to the detection unit.

[0173] For example, located at (x i ,y j The specific time matrix of the detection unit at this location at a certain analysis time can be TT=[T(x i ,y j k t ),T(x i ,y j ,k t+1 )], where T(x i ,y j k t ) can be the trigger time of the most recently occurring photon event on the detection unit, T(x) i ,y j ,k t+1 () can be the current analysis time. Located in (x i ,y j The state matrix of the detection unit at this location at a certain analysis time can be specifically represented as SS=[S(x i ,y j ,k t ),S(x i ,y j ,k t+1 The first state matrix can be represented as [0, 1], the second state matrix as [1, 1], the third state matrix as [1, 0], and the fourth state matrix as [0, 0].

[0174] In this embodiment, the electronic device records the triggering time of the detection unit through a time matrix and the triggering state of the detection unit through a state matrix. This facilitates parallel computing by the electronic device, thereby improving data processing speed and accelerating the running efficiency of the simulation model.

[0175] S2032. Based on the triggering state of the photon event on each detection unit, obtain the number of triggers of the photon event corresponding to the detection array at the analysis time.

[0176] In this embodiment, for any analysis time during the simulation process, after the electronic device determines the trigger state corresponding to each detection unit at that analysis time, it can determine the number of times the photon event of the detection array is triggered at that analysis time based on the trigger states corresponding to all detection units.

[0177] In one possible implementation, for any analysis moment during the simulation process, the electronic device can count the number of detection units on the detection array that are in the triggered state to determine the number of times the photon event corresponding to the detection array is triggered at that analysis moment.

[0178] In one possible implementation, when the triggering state of a photon event on a detection unit is represented by a state matrix, for any analysis moment in the simulation process, the electronic device can count the number of detection units whose state matrix is ​​either the first state matrix or the second state matrix, and determine the number of detection units whose state matrix is ​​either the first state matrix or the second state matrix as the number of times the photon event is triggered by the detection array at the current analysis moment.

[0179] The method provided in this embodiment allows electronic devices to determine whether a photon event has occurred on a detection unit based on the triggering time and triggering state of the detection unit. Compared with the dead-time model in the prior art, the method provided in this embodiment has a smaller computational load, thereby improving the computational efficiency of the simulation model.

[0180] Figure 10 This application illustrates a simulation method for a time-of-flight measurement system based on a single-photon avalanche diode, as provided in an embodiment of this application. Figure 10As shown, when a user needs to perform simulation calculations on a time-of-flight measurement system based on a single-photon avalanche photodiode, the user can input the distribution area of ​​echo photons on the detection array of the time-of-flight measurement system, the first parameter of the time-of-flight measurement system, the second parameter of the target object, and the fourth parameter of sunlight into the electronic device. The electronic device can perform a negative binomial distribution operation based on the distribution area, the first parameter of the time-of-flight measurement system, the second parameter of the target object, and the fourth parameter of sunlight to calculate the number of echo received photons and the number of noise received photons arriving on the detection array at each analysis time. Then, the electronic device can input the number of echo received photons into a first random function to generate a first coordinate corresponding to each echo photon, thereby determining the detection unit where each echo photon arrives within the distribution area. The electronic device can also input the number of noise received photons into a second random function to generate a second coordinate corresponding to each noise photon, thereby determining the detection unit where each noise photon arrives within the receiving area.

[0181] For a detection unit that receives echo photons and / or noise photons, the electronic device can acquire the time matrix of the detection unit. If the time matrix of the detection unit does not contain a trigger time, the electronic device can write the current analysis time as the trigger time into the time matrix and update the state matrix of the detection unit to the first state matrix.

[0182] If the time matrix of the detection unit contains a trigger time, the electronic device can calculate the time difference between the trigger time in the time matrix and the current analysis time. The electronic device can determine whether the time difference between the trigger time and the current analysis time is less than the dead time. If the time difference between the trigger time and the current analysis time is less than the dead time, the electronic device may not update the trigger time in the time matrix and will update the state matrix corresponding to the detection unit to the third state matrix. If the time difference between the trigger time and the current analysis time is greater than or equal to the dead time, the electronic device can update the trigger time of the detection unit according to the current analysis time and update the state matrix of the detection unit to the second state matrix.

[0183] Then, the electronic device can iteratively count the state matrices of all detection units, count the number of detection units whose state matrix is ​​either the first or second state matrix at the current analysis time, and determine the number of detection units with the first or second state matrix as the trigger count of photon events. The electronic device can accumulate the trigger count of photon events corresponding to the detection array within the analysis period and generate histogram data corresponding to the detection array.

[0184] It should be noted that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0185] Figure 11 This illustration shows a schematic diagram of a photon receiving simulation device for a time-of-flight measurement system according to an embodiment of this application. Specifically, it may include an incident photon acquisition module 1101, a photon count determination module 1102, a trigger count determination module 1103, and a histogram generation module 1104, wherein:

[0186] The incident photon acquisition module 1101 is used to acquire the number of incident photons arriving at the detector array at each analysis time within the analysis period.

[0187] The photon count determination module 1102 is used to obtain the number of received photons corresponding to each of the detection units at the analysis time based on the number of incident photons and the distribution area of ​​the incident photons.

[0188] The trigger count determination module 1103 is used to obtain the trigger count of the photon event corresponding to the detection array at the analysis time based on the number of received photons corresponding to each detection unit at the analysis time and the photon event triggering model;

[0189] The histogram generation module 1104 is used to accumulate the number of triggers of photon events corresponding to the detection array within the analysis period to obtain histogram data corresponding to the detection array. The histogram data is used to determine the performance indicators of the detection array.

[0190] The photon count determination module 1102 can also be used to calculate the number of received photons corresponding to the detection array based on the number of incident photons and the spot dispersion; and to obtain the number of received photons corresponding to each detection unit at the analysis time based on the number of received photons and the distribution area of ​​the incident photons.

[0191] The photon count determination module 1102 can also be used to determine the spot dispersion; calculate the number of echo received photons based on the spot dispersion, the number of echo photons, and the negative binomial distribution function; and calculate the number of noise received photons based on the spot dispersion, the number of noise photons, and the negative binomial distribution function.

[0192] The photon count determination module 1102 can also be used to obtain the echo region where the echo photons are distributed on the detector array and the noise region where the noise photons are distributed on the detector array; randomly generate a first coordinate of each echo photon on the detector array based on the number of echo received photons and the echo region; randomly generate a second coordinate of each noise received photon on the detector array based on the number of noise received photons and the noise region; and obtain the number of received photons corresponding to each detector unit at the analysis time based on the first coordinates of all echo received photons and the second coordinates of all noise received photons.

[0193] The trigger count determination module 1103 can also be used to determine the trigger state of the photon event on each detection unit according to the number of received photons and the trigger time at the analysis time. The trigger state includes a triggered state and a non-triggered state. Based on the trigger state of the photon event on each detection unit, the trigger count of the photon event corresponding to the detection array at the analysis time can be obtained.

[0194] The trigger count determination module 1103 can also be used to count the number of the detection units whose trigger state is triggered, and obtain the trigger count of the photon event corresponding to the detection array at the analysis time.

[0195] The trigger count determination module 1103 can also be used to determine the trigger state of the photon event on the detection unit as triggered when the trigger time is empty and the number of photons received by the detection unit at the analysis time is greater than 0; or to determine the trigger state of the photon event on the detection unit as untriggered when the trigger time is empty and the number of photons received by the detection unit at the analysis time is equal to 0.

[0196] The trigger count determination module 1103 can also be used to calculate the time difference between the analysis time and the trigger time when the trigger time is not empty, wherein the trigger time is earlier than the analysis time; when the time difference is greater than or equal to the dead time of the detection unit and the number of received photons corresponding to the detection unit at the analysis time is greater than 0, determine the trigger state of the photon event on the detection unit as triggered; or when the time difference is greater than or equal to the dead time of the detection unit and the number of received photons corresponding to the detection unit at the analysis time is equal to 0, determine the trigger state of the photon event on the detection unit as untriggered; or when the time difference is less than the dead time of the detection unit, determine the trigger state of the photon event on the detection unit as untriggered.

[0197] The trigger count determination module 1103 can also be used to update the trigger time of the detection unit based on the analysis time.

[0198] The incident photon acquisition module 1101 can also be used to calculate the number of incident photons based on the first parameters of the time-of-flight measurement system, the second parameters of the target object, the third parameters of the probe light, and the fourth parameters of sunlight. The first parameters include the optical efficiency of the time-of-flight measurement system, the optical efficiency of the transmitter, the emission power of the transmitter, the photon detection efficiency of the detector array, the atmospheric transmittance, the first receiving area of ​​the detector array, and the distance between the transmitter and the target object. The second parameters include the reflectivity of the target object and the second receiving area of ​​the target object. The third parameters include the power of the probe light, the frequency of the probe light, the pulse interval of the probe light, and the divergence angle of the probe light. The fourth parameters include solar irradiance, the angle between sunlight and the surface normal of the target object, and the bandwidth of the filter in the time-of-flight measurement system.

[0199] The incident photon acquisition module 1101 can also be used to calculate the number of echo photons based on the first parameter, the second parameter and the third parameter; and to calculate the number of noise photons based on the first parameter, the second parameter and the fourth parameter.

[0200] As the apparatus embodiments are basically similar to the method embodiments, they are described in a relatively simple manner. For relevant details, please refer to the description in the method embodiment section.

[0201] Reference Figure 12 The diagram illustrates an electronic device according to an embodiment of this application. Figure 12 As shown, the electronic device 1200 in this embodiment includes: a processor 1210, a memory 1220, and a computer program 1221 stored in the memory 1220 and executable on the processor 1210. When the processor 1210 executes the computer program 1221, it implements the steps in various embodiments of the photon receiving simulation method for the time-of-flight measurement system described above, for example... Figure 2 Steps S201 to S204 are shown. Alternatively, when the processor 1210 executes the computer program 1221, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 11 The functions of modules 1101 to 1104 are shown.

[0202] For example, the computer program 1221 can be divided into one or more modules / units, which are stored in the memory 1220 and executed by the processor 1210 to complete this application. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which can be used to describe the execution process of the computer program 1221 in the electronic device 1200. For example, the computer program 1221 can be divided into an incident photon acquisition module, a photon count determination module, a trigger count determination module, and a histogram generation module, with the specific functions of each module as follows:

[0203] An incident photon acquisition module is used to acquire the number of incident photons arriving at the detector array at each analysis time within the analysis period.

[0204] A photon count determination module is used to determine the number of received photons corresponding to each detection unit at the analysis time based on the number of incident photons and the distribution area of ​​the incident photons.

[0205] The trigger count determination module is used to determine the trigger count of the photon event corresponding to the detection array at the analysis time based on the number of received photons corresponding to each detection unit at the analysis time and the photon event triggering model;

[0206] The histogram generation module is used to accumulate the number of triggers of photon events corresponding to the detection array within the analysis period to obtain histogram data corresponding to the detection array. The histogram data is used to determine the performance indicators of the detection array.

[0207] The electronic device 1200 can be a desktop computer, cloud server, or other computing device. The electronic device 1200 may include, but is not limited to, a processor 1210 and a memory 1220. Those skilled in the art will understand that... Figure 12 This is merely one example of electronic device 1200 and does not constitute a limitation on electronic device 1200. It may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device 1200 may also include input / output devices, network access devices, buses, etc.

[0208] The processor 1210 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (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 can be a microprocessor or any conventional processor.

[0209] The memory 1220 can be an internal storage unit of the electronic device 1200, such as a hard disk or memory of the electronic device 1200. The memory 1220 can also be an external storage device of the electronic device 1200, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc., equipped on the electronic device 1200. Furthermore, the memory 1220 can include both internal and external storage units of the electronic device 1200. The memory 1220 is used to store the computer program 1221 and other programs and data required by the electronic device 1200. The memory 1220 can also be used to temporarily store data that has been output or will be output.

[0210] This application also discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the photon receiving simulation method of the time-of-flight measurement system as described in the foregoing embodiments.

[0211] This application also discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the photon receiving simulation method of the time-of-flight measurement system as described in the foregoing embodiments.

[0212] This application also discloses a computer program product that, when run on a computer, causes the computer to execute the photon receiving simulation method of the time-of-flight measurement system described in the foregoing embodiments.

[0213] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A photon receiving simulation method for a time-of-flight measurement system, characterized in that, The time-of-flight measurement system includes a transmitter and a detector array. The transmitter emits probe light, and the detector array includes multiple detector units. The detector array receives the echo light formed by the probe light reflected from a target object. The method includes: For each analysis time within the analysis period, the number of incident photons arriving at the detector array at that analysis time is obtained, wherein the incident photons include echo photons and noise photons; The echo region where the echo photons are distributed on the detector array and the noise region where the noise photons are distributed on the detector array are obtained. Based on the number of echo photons and the echo region, the number of echo received photons corresponding to each detection unit at the analysis time is obtained; Based on the number of noise photons and the noise region, the number of noise-received photons corresponding to each detection unit at the analysis time is obtained; Based on the number of echo photons received by each detection unit at the analysis time, the number of noise photons received by each detection unit at the analysis time, and the photon event triggering model, the number of triggering times of the photon event corresponding to the detection array at the analysis time is obtained. The number of triggers of photon events corresponding to the detection array within the analysis period is accumulated to obtain the histogram data corresponding to the detection array. The histogram data is used to determine the performance indicators of the detection array.

2. The method according to claim 1, characterized in that, The method of obtaining the number of echo photons received by each detection unit at the analysis time based on the number of echo photons and the echo region includes: Determine the spot divergence; The number of received echo photons is calculated based on the spot divergence, the number of echo photons, and the negative binomial distribution function. Based on the number of echo received photons and the echo region, a first coordinate of each echo received photon on the detection array is randomly generated; Based on the first coordinates of all the echo received photons, the number of echo received photons corresponding to each detection unit at the analysis time is obtained.

3. The method according to claim 1, characterized in that, The process of obtaining the number of noise-received photons corresponding to each detection unit at the analysis time based on the number of noise photons and the noise region includes: Determine the spot divergence; The number of noise-received photons is calculated based on the spot divergence, the number of noise photons, and the negative binomial distribution function. Based on the number of noise-received photons and the noise region, a second coordinate of each noise-received photon on the detection array is randomly generated; The number of noise-received photons corresponding to each detection unit at the analysis time is obtained based on the second coordinates of all the noise-received photons.

4. The method according to claim 1, characterized in that, The step of obtaining the number of photon events triggered by the detector array at the analysis time based on the number of echo photons received by each detector unit at the analysis time, the number of noise photons received by each detector unit at the analysis time, and the photon event triggering model includes: For each detection unit, the triggering state of the photon event on the detection unit is determined based on the number of echo received photons, the number of noise received photons, and the triggering time corresponding to the detection unit at the analysis time. The triggering state includes a triggered state and a non-triggered state. Based on the triggering state of the photon event on each of the detection units, the number of times the photon event corresponding to the detection array is triggered at the analysis time is obtained.

5. The method according to claim 4, characterized in that, The step of obtaining the number of times the photon event corresponding to the detection array is triggered at the analysis time based on the triggering state of the photon event on each of the detection units includes: The number of detection units in the triggered state is counted to obtain the number of times the photon event corresponding to the detection array is triggered at the analysis time.

6. The method according to claim 1, characterized in that, The step of obtaining the number of incident photons arriving at the detector array at the analysis time includes: The number of incident photons is calculated based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, the third parameter of the probe light, and the fourth parameter of the sunlight. The first parameter includes the optical efficiency of the time-of-flight measurement system, the optical efficiency of the transmitter, the emission power of the transmitter, the photon detection efficiency of the detector array, the atmospheric transmittance, the first receiving area of ​​the detector array, and the distance between the transmitter and the target object. The second parameter includes the reflectivity of the target object and the second receiving area of ​​the target object. The third parameter includes the power of the probe light, the frequency of the probe light, the pulse interval of the probe light, and the divergence angle of the probe light. The fourth parameter includes the solar irradiance, the angle between the sunlight and the normal to the surface of the target object, and the bandwidth of the filter in the time-of-flight measurement system.

7. The method according to claim 6, characterized in that, The incident photons include echo photons and noise photons. The calculation of the number of incident photons based on the first parameter of the time-of-flight measurement system, the second parameter of the target object, the third parameter of the probe light, and the fourth parameter of sunlight includes: The number of echo photons is calculated based on the first parameter, the second parameter, and the third parameter; The number of noise photons is calculated based on the first parameter, the second parameter, and the fourth parameter.

8. An electronic device, characterized in that, include: Memory, used to store executable program code; A processor is configured to call and run the executable program code from the memory, causing the electronic device to perform a photon receiving simulation method for a time-of-flight measurement system as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, implements a photon receiving simulation method for a time-of-flight measurement system as described in any one of claims 1-7.

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