Reflectivity correction ToF ranging method and device, equipment and storage medium

Abstract

The embodiment of the invention discloses a reflectivity correction ToF ranging method and device, equipment and a storage medium. The method comprises the following steps: acquiring a statistical result of photon flight time of a light pulse reflected by a to-be-measured target; wherein the statistical result comprises the detection time of the photons and the number of the photons corresponding to the detection time; according to the statistical result, determining the starting time when the light pulse is detected; and determining the distance of the to-be-detected target according to the starting time of detecting the optical pulse and the starting time of transmitting the optical pulse. Through the scheme, the accuracy of determining the distance of the to-be-measured target can be improved.

Description

Technical Field

[0001] The present disclosure relates to but is not limited to the field of distance measurement, and in particular to a reflectivity-corrected ToF distance measurement method, device, equipment and storage medium. Background Art

[0002] Generally, the photon time of flight (ToF) distance measurement method is to emit a light pulse through a light pulse transmitter (such as a laser transmitter), and after the light pulse is irradiated to the target to be measured, it is diffusely reflected to the photon detector by the target to be measured; the start time of the light pulse transmitter emitting the light pulse and the end time of the photon detector detecting the photon reflected by the target to be measured are recorded by a timer to determine the photon flight time, and then the distance of the target to be measured is converted according to the relationship between the speed of light, time and distance. In the actual application of the related technology, a large number of photon flight events are generally generated by emitting light pulses multiple times, and then a histogram is obtained by counting the number of events corresponding to the photon flight time, and the peak position of the histogram is determined as the photon flight time of the target distance to be measured, and then the position of the target to be measured is determined according to the photon flight time. However, there is an inaccurate problem in the related technology of using the peak position of the histogram to determine the photon flight time of the target to be measured, and the root cause is: the peak value of the histogram deviates from the peak value of the histogram of the theoretical distance, and the reasons for the deviation include various situations, which are specifically shown in the specification and related drawings of the present disclosure. How to improve the accuracy of determining the photon flight time and thus improve the accuracy of the ranging results needs to be solved urgently. Summary of the invention

[0003] In view of this, the embodiments of the present disclosure are intended to provide a reflectivity-corrected ToF ranging method, apparatus, device, and storage medium.

[0004] In a first aspect, an embodiment of the present disclosure provides a reflectivity corrected ToF ranging method, the method comprising:

[0005] Obtaining a statistical result of the photon flight time of the light pulse reflected by the target to be measured; wherein the statistical result includes the detection time of the photon and the number of photons corresponding to the detection time;

[0006] Determining the start time of the detected light pulse according to the statistical results;

[0007] The distance of the target to be detected is determined according to the start time of detecting the light pulse and the start time of emitting the light pulse.

[0008] In some embodiments, determining the start time of detecting the light pulse according to the statistical result includes:

[0009] According to the statistical results, determining the distribution center and concentration of the number of photons at the detection time;

[0010] The start time of the detected light pulse is determined according to the distribution center and concentration of the number of photons at the detection time.

[0011] In some embodiments, the aggregation degree includes: one of a weighted value of peak broadening, a half-height width, a correlation value of a standard deviation, and a correlation value of a quartile of the statistical result in a histogram;

[0012] The relevant value of the standard deviation refers to the length of the time interval corresponding to the integer multiple standard deviation or non-integer multiple standard deviation of the statistical result in the histogram;

[0013] The quartile correlation value refers to the length of the time interval corresponding to any two quartiles of the statistical result in the histogram.

[0014] In some embodiments, determining the start time of the detected light pulse according to the distribution center and concentration of the number of photons at the detection time includes:

[0015] The starting time of detecting the photons is determined by subtracting the concentration degree from the distribution center of the photon quantity at the detection time.

[0016] In some embodiments, the standard deviation is a distribution standard deviation or a mapping standard deviation;

[0017] The distribution standard deviation refers to the standard deviation reflecting the distribution of the number of photons over the detection time;

[0018] The mapping standard deviation refers to a standard deviation determined by the number of photons according to a preset mapping relationship.

[0019] In some embodiments, the start time of emitting the light pulse includes:

[0020] One of the generation time of the control signal, the reception time of the control signal or the actual emission time of the light pulse; wherein the control signal is a signal for controlling the emission of the light pulse.

[0021] In some embodiments, determining the start time of the detected light pulse according to the distribution center and concentration of the number of photons at the detection time includes:

[0022] Acquire a compensation coefficient related to the concentration, and use the compensation coefficient to compensate for the concentration;

[0023] The distribution center of the photon quantity at the detection time minus the compensated concentration is determined as the start time of the detected light pulse.

[0024] In some embodiments, determining the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse includes:

[0025] Get the calibration error;

[0026] Determining a time difference between a start time of detecting the light pulse and a start time of emitting the light pulse;

[0027] The distance of the target to be measured is determined according to the calibration error and the time difference.

[0028] In a second aspect, an embodiment of the present disclosure provides a reflectivity-corrected ToF ranging device, the device comprising:

[0029] A single photon response module, used to respond to detection photons; wherein the photons include photons after the light pulse is reflected by the target to be detected;

[0030] A time information module, used to obtain the detection time of the photons of the light pulse;

[0031] A counting module, used to count and count the detected photons to obtain statistical results; wherein the statistical results include the detection time of the photons and the number of photons corresponding to the detection time;

[0032] The data processing module is used to determine the start time of detecting the light pulse according to the statistical results; and to determine the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse.

[0033] In some embodiments, the data processing module is used to determine the distribution center and concentration of the number of photons at the detection time based on the statistical results; and determine the start time of the detected light pulse based on the distribution center and concentration of the number of photons at the detection time.

[0034] In some embodiments, the aggregation degree includes: one of a weighted value of peak broadening, a half-height width, a correlation value of a standard deviation, and a correlation value of a quartile of the statistical result in a histogram;

[0035] The relevant value of the standard deviation refers to the length of the time interval corresponding to the integer multiple standard deviation or non-integer multiple standard deviation of the statistical result in the histogram;

[0036] The quartile correlation value refers to the length of the time interval corresponding to any two quartiles of the statistical result in the histogram.

[0037] In some embodiments, the data processing module is used to subtract the concentration degree from the distribution center of the number of photons at the detection time to determine the start time of the detection of the photons.

[0038] In some embodiments, the standard deviation is a distribution standard deviation or a mapping standard deviation;

[0039] The distribution standard deviation refers to the standard deviation reflecting the distribution of the number of photons over the detection time;

[0040] The mapping standard deviation refers to a standard deviation determined by the number of photons according to a preset mapping relationship.

[0041] In some embodiments, the start time of emitting the light pulse includes:

[0042] One of the generation time of the control signal, the reception time of the control signal or the actual emission time of the light pulse; wherein the control signal is a signal for controlling the emission of the light pulse.

[0043] In some embodiments, the data processing module is used to obtain a compensation coefficient related to the concentration, and use the compensation coefficient to compensate for the concentration; the distribution center of the number of photons at the detection time minus the compensated concentration is subtracted to determine the start time of the detected light pulse.

[0044] In some embodiments, the data processing module is used to obtain a calibration error; determine the time difference between the start time of detecting the light pulse and the start time of emitting the light pulse; and determine the distance of the target to be measured based on the calibration error and the time difference.

[0045] In a third aspect, an embodiment of the present disclosure provides a reflectivity-corrected ToF ranging device, including:

[0046] A single photon response module, used to respond to detection photons; wherein the photons include photons after the light pulse is reflected by the target to be detected;

[0047] A time information module, used to obtain the detection time of the photons of the light pulse;

[0048] A counting module, used to count and count the detected photons to obtain statistical results; wherein the statistical results include the detection time of the photons and the number of photons corresponding to the detection time;

[0049] The data processing module is used to determine the start time of detecting the light pulse according to the statistical results; and to determine the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse.

[0050] In a fourth aspect, an embodiment of the present disclosure provides a storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method described in the first aspect is implemented.

[0051] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0052] The start time of the light pulse detected by the embodiment of the present disclosure is not affected by the intensity of the reflected light pulse, and the start time of the light pulse detected is only related to the distance of the target to be measured. Therefore, the embodiment of the present disclosure determines the distance of the target to be measured based on the start time of the light pulse detected and the start time of the emitted light pulse determined based on the statistical results, which can reduce the influence on the distance measurement result caused by the different reflectivity of the target to be measured and the excessive intensity of the reflected light pulse when the target to be measured is close, thereby improving the accuracy of determining the distance of the target to be measured.

[0053] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is the distance measurement principle diagram of the direct photon time-of-flight method;

[0055] Figure 2 Schematic diagram of SPAD's response to photons reflected from targets with different reflectivities;

[0056] Figure 3 Example of comparing the statistical histograms for measuring the distance to targets with the same distance and different reflectivity when emitting the same light pulse Figure 1 ;

[0057] Figure 4 This is an example diagram of the statistical comparison of the number of photons detected by SPAD under different light intensities; Figure 4 An example diagram of the comparison of the peak values ​​of the statistical histogram when emitting the same light pulse to measure the distance to the target with the same distance and different reflectivity;

[0058] Figure 5 An example diagram of a distance measurement system provided by an embodiment of the present disclosure;

[0059] Figure 6 An example diagram of the duration of a timer recording detection photons provided by an embodiment of the present disclosure;

[0060] Figure 7 A reflectivity correction ToF ranging method process provided in the embodiment of the present disclosure Figure 1 ;

[0061] Figure 8Example of comparing the statistical histograms for measuring the distance to targets with the same distance and different reflectivity when emitting the same light pulse Figure 2 ;

[0062] Fig. 9 An example diagram of a half-height width reflecting the degree of aggregation provided in an embodiment of the present disclosure;

[0063] Fig.10 An example diagram of a standard deviation correlation value reflecting the degree of aggregation provided in an embodiment of the present disclosure;

[0064] Fig.11 An example diagram of a quartile correlation value reflecting the degree of aggregation provided in an embodiment of the present disclosure;

[0065] Fig.12 A reflectivity correction ToF ranging method process provided in the embodiment of the present disclosure Figure 2 ;

[0066] Fig.13 An example diagram of a reflectivity-corrected ToF ranging device provided in an embodiment of the present disclosure;

[0067] Fig.14 A reflectivity-corrected ToF ranging device is provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0068] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0069] The photon time-of-flight method includes the indirect time-of-flight method (iToF) and the direct time-of-flight method (dToF). Among them, the principle of the direct time-of-flight method (dToF) is to measure the distance directly based on the time difference between pulse emission and reception. The electronic clock is activated at the moment of laser emission, and the beam steering unit guides the pulse to the desired direction. The pulse is reflected back from the target to be measured, and a part of it is received by the photodetector. The photodetector connected to the front-end electronic device generates an electrical signal, which makes the clock effective. By measuring the flight time Δt, the distance d to the reflecting object is calculated. The calculation formula is d=c*Δt / 2, where c refers to the speed of light in the medium. In practical applications, due to the randomness of the time when photons arrive at the photodetector, laser pulses are generally emitted multiple times, and the photon flight time statistical histogram is used to count the photon flight time of a large number of laser pulses. The photon flight time with the highest frequency is determined to be the flight time of the photon reflected by the target to be measured, so as to obtain the distance of the target to be measured.

[0070] In the related art, the peak position in the statistical histogram is generally determined as the flight time of the photon reflected by the target to be measured. However, when the reflectivity of the target to be measured is high, the detection peak may be formed in advance, that is, the detection peak is offset from the ideal peak reflecting the true distance of the target, which leads to measurement errors. This is because the detection element of the photodetector, such as the single photon avalanche diode (SPAD), has a dead time after responding to the photon. The SPAD is in a "saturated state" during the dead time and can no longer detect photons. The target to be measured with a higher reflectivity reflects back a light pulse with a larger light intensity, causing most of the SPAD pixels in the SPAD array to quickly enter the dead time, so they cannot respond to the subsequent photons, resulting in the detection peak appearing in advance. The following is a detailed explanation with reference to the diagram.

[0071] Figure 1 This is the principle diagram of direct photon time-of-flight distance measurement. Figure 1In the figure, I1 indicates the relationship between the emission time and intensity of the light pulse. I2 indicates the relationship between the number of incident photons that reach the photodetector after reflection of multiple light pulses and the detection time, where each circle represents an incident photon, including photons responded by the SPAD and photons not responded by the SPAD. I3 indicates that the SPAD generates a pulse signal in response to the incident photons, and the statistical result obtained by performing histogram statistics on the time and number of generated pulse signals, where, since the SPAD generates a pulse signal each time it responds to an incident photon, the number of pulse signals is actually the number of incident photons responded by the SPAD. The histogram includes the distribution of the number of photons in each time bin; a time bin represents a time interval with a certain time length, and the number of photons corresponding to the time bin is the sum of the number of photons detected at each detection time falling into the time interval. Exemplarily, in the histogram marked by I3, the number of photons corresponding to time bin N is the sum of the number of incident photons responded to by the SPAD after the first light pulse is emitted in I2, the number of incident photons responded to by the SPAD after the second light pulse is emitted, the number of incident photons responded to by the SPAD after the third light pulse is emitted, the number of incident photons responded to by the SPAD after the fourth light pulse is emitted, and so on.

[0072] In the related art, based on the histogram statistical results shown in I3 above, the time corresponding to the peak of the number of photons is determined to be the photon flight time, so that the distance of the target to be measured is calculated based on the following formula (1).

[0073] S = v*(t / 2); (1)

[0074] Among them, v represents the speed of light and t represents the flight time of the photon.

[0075] Figure 2 This is a schematic diagram of the SPAD's response to photons reflected from targets with different reflectivities. Figure 2 In the figure, when the intensity of the emitted light pulse is the same, for the target with low reflectivity, the intensity of the reflected light pulse is lower, the number of photons is smaller, and the time interval between each photon reaching the SPAD is greater than the dead time of the SPAD, so that the SPAD can detect all photons. However, for the target with high reflectivity, the intensity of the reflected light pulse is higher, the number of photons is larger and the density is higher, and the time interval between photons is shorter than the dead time of the SPAD, so that the SPAD cannot sense subsequent photons within the dead time (rectangular frame) after sensing the photon. Figure 1 As shown in the I2 diagram in the figure, due to the dead time of SPAD, SPAD can only sense the first incident photon arriving in each light pulse. The incident photons that arrive subsequently to the light pulse cannot be sensed, and no pulse count / photon count can be generated.

[0076] Figure 3 This is an example of comparing the photon flight time statistical histograms when emitting the same light pulse to measure the distance to the target with the same distance and different reflectivity. Figure 1 , Figure 3 In the figure, op indicates the waveform of the intensity of the emitted light pulse over time, and dp indicates the waveform of the intensity of the light pulse after being reflected by the target under ideal conditions (such as the absence of signal attenuation, optical noise, response loss, etc.). It can be understood that the horizontal axis of the highest point of op corresponds to the time of emitting the light pulse, and the horizontal axis of the highest point of dp corresponds to the time of receiving the light pulse under ideal conditions. The duration t between the time of emitting the light pulse and the time of receiving the light pulse is the photon flight time under ideal conditions. Figure 3 In the figure, ap, bp, and cp indicate the contour curves of the statistical results of the photon flight time of the light pulse op after being reflected by different targets to be measured in actual applications. Among them, ap indicates the histogram statistical results obtained by the photon flight time method for the target to be measured with the first reflectivity, bp indicates the histogram statistical results obtained by the photon flight time method for the target to be measured with the second reflectivity, and cp indicates the histogram statistical results obtained by the photon flight time method for the target to be measured with the third reflectivity, wherein the first reflectivity is greater than the second reflectivity, and the second reflectivity is greater than the third reflectivity. Since there are problems such as light attenuation after the light pulse is emitted, the light intensity reflected in the histogram (positively correlated with the number of photons) is lower than the light intensity of the emitted light pulse, that is, the contour vertex heights of ap, bp, and cp are lower than the vertex height of op.

[0077] according to Figure 3 It can be seen that when the same emission light pulse op is used to measure the distance of the target to be measured at the same distance but with different reflectivity, the corresponding statistical results of the photon flight time reflected in the histogram are also different, wherein the surfaces of the target to be measured with different reflectivity include reflective strips, white surfaces, black surfaces, stainless steel surfaces, glass mirrors, etc. For example, the peak height, peak width, and time corresponding to the highest peak of ap, bp, and cp are all different, resulting in different distances of the target to be measured calculated based on the peak position of the histogram in traditional histogram data processing. It is understandable that since the light intensity of the light pulse reflected by the close-range target to be measured and the high-reflectivity target to be measured is relatively large, the close-range target to be measured will also have the same problem as the high-reflectivity target to be measured, that is, the problem of measurement error caused by the detection peak offset.

[0078] As can be seen from the above, when the intensity of the reflected light pulse is large, such as when the reflectivity of the target to be measured is large, and / or when the target to be measured is close, the peak value in the histogram is shifted due to the rapid entry of the SPAD into the dead zone. Therefore, it is inaccurate to use the peak position in the histogram (i.e., the vertex of the curve profile in the histogram) to determine the distance of the target to be measured. Specifically, although the distances of two targets to be measured with different reflectivities are the same, the detected distance values ​​are different; or the actual distances of two targets to be measured with the same reflectivity are different, but the detected distance values ​​are the same. Both of the above situations will cause measurement errors.

[0079] In order to solve the above problems, the present disclosure proposes the following solutions:

[0080] Figure 5 This is an example diagram of a distance measurement system provided by an embodiment of the present disclosure, wherein L1 identifies a laser, L2 identifies an optical transmitting system, and the light pulse generated by the laser is emitted through the optical transmitting system. The light pulse generated by the laser is also emitted through the lens identified by L3, triggering the timer identified by L4 to start timing. Exemplarily, the timer is a time to digital converter (TDC). The light pulse emitted by the optical transmitting system is reflected by the target to be measured identified by L0, received by the optical receiving system identified by L5, and detected by the detection system identified by L6; when the detection system detects the photon, the timer is triggered to end the timing, thereby obtaining the duration of the detection photon based on the timer. After determining the duration of the detection photon, the signal processing system identified by L7 processes the statistical data of the number of detection photons and the duration of the detection photon to determine the photon flight time, and then calculates the distance between the optical transmitting system and the target to be measured through the aforementioned formula (1).

[0081] After obtaining the distance between the optical launch system and the target to be measured, Figure 5 The display device marked with L8 in the figure displays the distance result of the target to be measured.

[0082] Figure 6 is an example diagram of a timer recording the duration of detection photons provided by an embodiment of the present disclosure, Figure 6 In the figure, M1 identifies the device that emits light pulses, corresponding to the aforementioned optical emission system; M0 identifies the target to be measured; M2 identifies the device that detects light pulses, corresponding to the aforementioned optical receiving system and detection system; M3 identifies the duration of the detection photons recorded by the timer, which is the duration between the time when the light pulse is emitted and the time when the light pulse is detected.

[0083] The embodiment of the present disclosure provides a reflectivity-corrected ToF ranging method, the execution subject of which may be a photon time-of-flight ranging device (referred to as ranging device). For example, the photon time-of-flight ranging method may be executed by a terminal device or a server, or may be executed by a ranging device including the aforementioned optical pulse transmitter, photon detector, timer and other devices. In some possible implementations, the photon time-of-flight ranging method may be implemented by a processor calling computer-readable instructions stored in a memory. The following description is made by taking the execution subject of the photon time-of-flight ranging method as a ranging device as an example.

[0084] Figure 7 The process of a reflectivity correction ToF ranging method provided by the embodiment of the present disclosure is shown Figure 1 ,Depend on Figure 7 It can be seen that the method includes:

[0085] S701, obtaining a statistical result of the photon flight time of the light pulse reflected by the target to be measured; wherein the statistical result includes the detection time of the photon and the number of photons corresponding to the detection time;

[0086] S702, determining the start time of the detected light pulse according to the statistical result;

[0087] S703: Determine the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse.

[0088] In the embodiments of the present disclosure, light pulses can be emitted by the aforementioned optical emission system, wherein the light source can be a light emitting diode (LED), a laser diode (LD), an edge emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), etc., and the light source emits light pulses outward under the driving control of a driver; the light pulses can be laser, infrared light, ultraviolet light, etc., and the embodiments of the present disclosure are not limited to this.

[0089] The disclosed embodiments can detect photons through the aforementioned optical receiving system, wherein the optical receiving system includes a detection end and an optical element for guiding light propagation, and the optical element may be one or more combinations of lenses, microlens arrays, reflectors, etc., and the optical signal is guided to the detection end through the optical element. The detection end may be a single-photon avalanche photodiode SPAD, or include a SPAD array composed of multiple SPADs, and the SPAD may respond to a single incident photon and output a pulse signal, and the counter connected to the SPAD outputs a digital signal, such as an output signal "0" indicating that no photon is detected, and an output signal "1" indicating that a photon is detected. In addition, the detection end may also include photoelectric conversion devices such as avalanche photodiodes, photomultiplier tubes, and silicon photomultiplier tubes.

[0090] After emitting a light pulse, the embodiment of the present disclosure, as described above, responds to the detection of photons by the photon receiving system to determine the detection time information of the detected photons and the number of photons corresponding to the detection time, so that in step S701, the ranging device obtains the statistical result of the photon flight time of the light pulse reflected by the target to be measured; wherein the statistical result includes the detection time of the photons and the number of photons corresponding to the detection time.

[0091] It should be noted that the statistical results of the embodiment of the present disclosure can be expressed by the corresponding relationship between the detection time of photons and the number of photons, or by a statistical histogram; wherein the horizontal axis of the histogram is a preset time box, each time box represents a time interval, and the number of photons corresponding to the time box is the sum of the number of photons detected at each detection time falling within the time interval.

[0092] In step S702, the distance measuring device determines the start time of detecting the light pulse according to the statistical results. For example, the time when the photon is first detected in the statistical results (the number of photons is greater than zero) can be determined as the start time of detecting the light pulse; or the time when the number of photons detected earliest in the statistical results is greater than a preset number threshold is determined as the start time of detecting the light pulse. In addition, the start time of detecting the light pulse can also be determined according to the shape of the histogram, such as the distribution center of the number of photons at the detection time, the distribution aggregation, etc., which is not limited in the present disclosure.

[0093] Figure 8 This is an example of comparing the photon flight time statistical histograms when emitting the same light pulse to measure the distance to the target with the same distance and different reflectivity. Figure 2 , combined with Figure 3It can be understood that the start time of the detected light pulse can be regarded as the first photon in the light pulse that is responded to by the SPAD. Its arrival time is not affected by the intensity of the reflected light pulse. The arrival time of the first photon is only related to the distance of the target to be measured. Therefore, in the statistical results marked by ap, bp, and cp corresponding to reflected light pulses of different intensities, the starting time point of the profile (i.e., the start time of the detected light pulse) is the same, which is point M.

[0094] Based on the use of the start time of the detected light pulse in the embodiment of the present disclosure, the error that may be caused by using the time corresponding to the peak of the histogram as the flight time of the photon reflected by the target to be measured in the prior art will be overcome. The reason is that because the embodiment of the present disclosure uses the start time of the detected light pulse to calculate the distance of the target to be measured, it will no longer be affected by the histogram peak offset, that is, because the embodiment of the present disclosure does not directly use the time corresponding to the peak of the histogram as the flight time of the photon reflected by the target to be measured, regardless of whether the peak of the histogram is offset, the photon flight time of the embodiment of the present disclosure is not affected by the peak offset error.

[0095] In step S703, the ranging device obtains the start time of emitting the light pulse; in some embodiments, the start time of emitting the light pulse includes: one of the generation time of the control signal, the reception time of the control signal, or the actual emission time of the light pulse; wherein the control signal is a signal for controlling the emission of the light pulse. Exemplarily, the generation time of the control signal may be the time when the signal processing system including electronic components such as CPU and MCU generates the control signal. The reception time of the control signal may be the time when the optical emission system receives the control signal, or the time when the timer (such as TDC) receives the control signal, wherein the optical emission system is used to emit the light pulse according to the received control signal, and the timer is used to start timing according to the received control signal. In addition, the ranging device may also determine the start time of emitting the light pulse based on other methods, such as the actual emission time of the light pulse determined after compensating the generation time of the control signal based on a preset time compensation parameter, or the actual emission time of the light pulse determined after fitting the time when the optical emission system receives the control signal based on a preset fitting function.

[0096] After determining the start time of detecting the light pulse and the start time of emitting the light pulse, the distance measuring device of the embodiment of the present disclosure uses the principle of photon flight time distance measurement to determine the position of the target to be measured.

[0097] In some embodiments, the time between the start time of detecting the light pulse and the start time of emitting the light pulse can be used as the photon flight time, and the distance to the target to be measured can be obtained based on the above formula (1).

[0098] In some embodiments, the time between the start time of the detected light pulse and the start time of the emitted light pulse can be used as the photon flight time. After the initial distance is obtained based on the above formula (1), it can be corrected by a preset calibration error, and the corrected result can be used as the distance to the target to be measured; wherein, the preset calibration error can be obtained through multiple tests.

[0099] It can be understood that the start time of the light pulse detected by the embodiment of the present disclosure is not affected by the intensity of the reflected light pulse, and the start time of the light pulse detected is only related to the distance of the target to be measured. Therefore, the embodiment of the present disclosure determines the distance of the target to be measured based on the start time of the light pulse detected and the start time of the emitted light pulse determined based on the statistical results, which can reduce the impact on the ranging result caused by the different reflectivity of the target to be measured and the excessive intensity of the reflected light pulse when the target to be measured is close, thereby improving the accuracy of determining the distance of the target to be measured.

[0100] In some embodiments, determining the start time of detecting the light pulse according to the statistical result includes:

[0101] According to the statistical results, determining the distribution center and concentration of the number of photons at the detection time;

[0102] The start time of the detected light pulse is determined according to the distribution center and concentration of the number of photons at the detection time.

[0103] In the disclosed embodiment, determining the distribution center of the number of photons at the detection time can be achieved in one of the following ways: for example, the detection time corresponding to the maximum number of photons in the statistical results can be determined as the distribution center, or the detection time corresponding to the highest peak in the histogram can be determined as the distribution center of the number of photons at the detection time, or a certain time (such as the center time) in the time box corresponding to the maximum number of photons in the histogram can be determined as the distribution center of the number of photons at the detection time. In addition, the centroid algorithm can be used to process the statistical results, determine the centroid of the histogram, and determine the detection time corresponding to the centroid as the distribution center of the number of photons at the detection time.

[0104] The distance measuring device of the embodiment of the present disclosure also determines the concentration of the number of photons in the detection time based on the statistical results, wherein the concentration represents the length of the time interval in which the distribution of the number of photons in the detection time meets a certain concentration requirement.

[0105] In some embodiments, the concentration of the number of photons in the detection time may be the length of the time interval between the first detection time when the number of photons is greater than the number threshold and the last detection time when the number of photons is greater than the number threshold.

[0106] In some embodiments, the concentration includes: one of the weighted value of the peak broadening of the statistical result in the histogram, the half-height width, the correlation value of the standard deviation, and the correlation value of the quartile; wherein the correlation value of the standard deviation refers to the length of the time interval corresponding to the integer multiple standard deviation or non-integer multiple standard deviation of the statistical result in the histogram. For example, it may be the length of the time interval corresponding to one standard deviation, two standard deviations, or three standard deviations of the statistical result in the histogram, or it may refer to the time length corresponding to 0.5 standard deviations, 1.5 standard deviations, 2.5 standard deviations, etc. of the statistical result in the histogram; wherein the integer multiple standard deviation and the non-integer multiple standard deviation can be set according to the actual statistical results, and the present disclosure does not make specific restrictions on this.

[0107] The correlation value of the quartile refers to the length of the time interval corresponding to any two quartiles of the statistical result in the histogram. For example, the correlation value of the quartile can be the length of the time interval corresponding to the interquartile range between the first quartile and the third quartile of the statistical result in the histogram, or the length of the time interval corresponding to the first quartile and the second quartile of the statistical result in the histogram, or the length of the time interval corresponding to the second quartile and the third quartile of the statistical result in the histogram, etc. Among them, the any two quartiles can be selected according to the actual statistical results, and the present disclosure does not make specific restrictions on this.

[0108] In some embodiments, the peak broadening may include bilateral peak width and unilateral peak width, wherein the bilateral peak width refers to the sum of the peak widths on both sides of the distribution center, and the unilateral peak width refers to the peak width on one side of the distribution center, which may be the peak width on the left or right side of the distribution center; if the peak broadening includes the bilateral peak width, the corresponding weighted value of the peak broadening is 1 / 2*bilateral peak width; if the peak broadening includes the unilateral peak width, the corresponding weighted value of the peak broadening is 1*unilateral peak width.

[0109] Fig. 9 An example diagram of a half-height width reflecting the degree of aggregation provided by an embodiment of the present disclosure is shown, Fig. 9 In the figure, the half-height position of the highest peak corresponds to time X1 and X2 respectively, and the time interval between X1 and X2 is the Full Width at Half Maxima (FWHM). If the waveform symmetry of the contour curve in the histogram is good, the half-height width is approximately equal to half of the double-sided peak width or approximately equal to the single-sided peak width. Under normal distribution, the relationship between the half-height width and the standard deviation σ can be expressed by the following formula (2):

[0110] FWHM≈2.355*σ; (2)

[0111] It can be understood that since the weighted value of the peak broadening, half-width, related value of the standard deviation, and related value of the quartile of the statistical results in the histogram can accurately characterize the aggregation of the distribution of the number of photons at the detection time, the embodiment of the present disclosure uses one of the weighted value of the peak broadening, half-width, related value of the standard deviation, and related value of the quartile of the statistical results in the histogram as the degree of aggregation, which can improve the accuracy of characterizing the aggregation of the distribution of the number of photons at the detection time, and thereby improve the accuracy of subsequent determination of the start time of the detected light pulse based on the degree of aggregation and the center of distribution.

[0112] like Fig.10 The embodiment of the present disclosure shown provides an example diagram of a standard deviation correlation value reflecting the degree of aggregation. When the curve profile of the statistical result in the histogram is approximately normal distribution, the degree of aggregation can be reflected by the standard deviation correlation value, and then the target distance can be obtained. Fig.10 In the equation, σ represents the standard deviation, and the abscissa "0" of the vertex position of the contour curve corresponds to the distribution center of the statistical result, wherein the time interval corresponding to -1*σ~0 (or 0~1*σ) is the aggregation represented by one standard deviation, the time interval corresponding to -2*σ~0 (or 0~2*σ) is the aggregation represented by two standard deviations, and the time interval corresponding to -3*σ~0 (or 0~3*σ) is the aggregation represented by three standard deviations. In the normal distribution, the data within the range of one standard deviation accounts for 34.1% of all data, the data within the range of two standard deviations accounts for 47.7% of all data; and the data within the range of three standard deviations accounts for 49.8% of all data.

[0113] In some embodiments, the standard deviation may be a distribution standard deviation or a mapping standard deviation; wherein the distribution standard deviation refers to a standard deviation that reflects the distribution of the number of photons at the detection time; specifically, the distribution standard deviation may be based on a known standard deviation formula, by processing the statistical results of the distribution of the number of photons at the detection time, to obtain a standard deviation that reflects the actual statistical results. Therefore, when the contour curve of the statistical results in the histogram presents or approaches a normal distribution, the concentration can be determined by the standard deviation of the statistical results. At this time, the standard deviation can better reflect the curve contour shape of the statistical results in the histogram, so that it has good data reliability when used to determine the concentration and obtain the distance of the target to be measured based on the concentration, thereby improving the accuracy of distance measurement.

[0114] In some embodiments, the mapping standard deviation refers to the standard deviation determined by the number of photons according to a preset mapping relationship; wherein the preset mapping relationship is obtained based on multiple photon time-of-flight ranging experiments, and the preset mapping relationship includes the "original image" and the "image" corresponding to the "original image".

[0115] In some embodiments, the "original image" may refer to the maximum number of photons in a unit time interval (such as a time bin of a histogram, etc.) in multiple experiments; the "image" may refer to the standard deviation of the distribution of statistical results in multiple experiments.

[0116] In some embodiments, the "original image" may refer to the sum of the number of photons in all unit time intervals (such as time bins of a histogram, etc.) in multiple experiments; the "image" may refer to the standard deviation of the distribution of statistical results in multiple experiments.

[0117] It should be noted that since multiple mapping relationships may be obtained through multiple experiments, a relatively stable mapping relationship can be obtained by statistically analyzing the mapping relationships of multiple experiments. The mapping relationship includes a first set composed of multiple "original images" and a second set composed of multiple "images", wherein each "original image" in the first set can be mapped to an "image" in the second set.

[0118] It is understandable that in actual applications, the curve profile of the statistical results obtained by detection in the histogram may be caused by noise and other factors (such as ambient light, dark counts, system jitter) causing burrs. These burrs will cause the calculated distribution standard deviation to be difficult to accurately reflect the shape of the waveform, and the concentration represented by the calculated distribution standard deviation will also have a large error. Therefore, when there is a large noise interference in the contour curve of the ranging statistical result, or when it does not present a normal distribution or is not close to a normal distribution in the histogram, the embodiment of the present disclosure can determine the mapping standard deviation based on a preset mapping relationship, and then more accurately represent the concentration of the number of photons in the detection time, so as to obtain an accurate distance to the target to be measured based on a more accurate concentration.

[0119] In some embodiments, the degree of aggregation can be reflected by quartile correlation values, for example, Fig.11 The embodiment of the present disclosure shown in the figure provides an example graph of quartile correlation values ​​reflecting the degree of aggregation, wherein D1 is the first quartile, D2 is the second quartile, D3 is the third quartile, the width between D3 and D1 is the interquartile range, and the length of the time interval corresponding to the interquartile range is the degree of aggregation.

[0120] In some embodiments, determining the start time of the detected light pulse based on the distribution center and concentration of the number of photons at the detection time includes: subtracting the concentration from the distribution center of the number of photons at the detection time to determine the start time of the detected photons.

[0121] In the disclosed embodiment, the distribution center (time point) of the statistical result minus the concentration (duration) can be determined as the start time of the detected light pulse; or based on the histogram, after the distribution center on the time axis is moved in the direction of decreasing time by the width of the concentration, the corresponding time is determined as the start time of the detected light pulse, wherein the concentration, as described above, can be one of the weighted value of the peak broadening, the half-height width, the correlation value of the standard deviation, and the correlation value of the quartile. The disclosed embodiment determines the start time of the detected light pulse by subtracting the concentration from the distribution center, and can use the existing statistical result parameters to determine the unknown parameters used for distance determination, which has the advantages of being simple and easy to implement, and the distance of the target to be measured that is finally obtained is not affected by factors such as the reflectivity of the surface of the target to be measured and the close distance of the target to be measured, and the ranging error is smaller.

[0122] It is understandable that in the photon time-of-flight ranging (ToF) method, because there is temporal randomness in the arrival of photons at the SPAD, if only the time of the first detection of photons is determined as the start time of the detection of the light pulse, there may be a large measurement error. Compared with only based on the time of the first detection of photons as the start time of the detection of the light pulse, the embodiment of the present disclosure determines the start time of the detection of the light pulse based on the distribution of the number of photons at the detection time, according to the distribution center and the concentration, which can eliminate the random error of the first detection of photons, improve the accuracy of the start time of the detection of the light pulse, and thus improve the accuracy of determining the distance of the target to be measured.

[0123] In addition, taking into account the influence of light attenuation and light noise (manifested as burrs on the contours in the histogram), the ranging device can also perform smoothing filtering on the statistical results after obtaining the statistical results, and determine the distribution center and concentration of the number of photons at the detection time in the statistical results after smoothing filtering.

[0124] In some embodiments, determining the start time of the detected light pulse according to the distribution center and concentration of the number of photons at the detection time includes:

[0125] Acquire a compensation coefficient related to the concentration, and use the compensation coefficient to compensate for the concentration;

[0126] The distribution center of the photon quantity at the detection time minus the compensated concentration is determined as the start time of the detected light pulse.

[0127] In the embodiment of the present disclosure, the distance measuring device obtains a compensation coefficient related to the concentration, uses the compensation coefficient to compensate for the concentration, and subtracts the compensated concentration from the distribution center of the number of photons at the detection time to determine the start time of the detected light pulse. The compensation coefficient related to the concentration can be obtained through multiple tests based on the required application environment, or can be calculated and determined based on the current measurement environment combined with the parameters of the distance measurement statistical results, which is not limited in the present disclosure.

[0128] Exemplarily, if the concentration is half-height width, the start time of the detected light pulse = distribution center - half-height width * compensation coefficient corresponding to the half-height width; if the concentration is the correlation value of the standard deviation, the start time of the detected light pulse = distribution center - correlation value of the standard deviation * compensation coefficient corresponding to the correlation value of the standard deviation. Through this scheme, the compensated concentration can be made to better match the interval between the distribution center and the start time of the detected light pulse, so that the use of the distribution center minus the concentration to determine the start time of the detected light pulse is more accurate, and the error correction of the concentration is realized, that is, the accuracy of determining the start time of the detected light pulse is improved, and then the accuracy of determining the distance of the target to be measured is improved.

[0129] In some embodiments, determining the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse includes:

[0130] Get the calibration error;

[0131] Determining a time difference between a start time of detecting the light pulse and a start time of emitting the light pulse;

[0132] The distance of the target to be measured is determined according to the calibration error and the time difference.

[0133] In the embodiment of the present disclosure, since the start time of the emission light pulse is difficult to determine due to factors such as delay in the control signal transmission, the photon flight time determined based on the start time of the detected light pulse and the start time of the emission light pulse may have errors because the determined start time of the emission light pulse is not the actual emission time of the light pulse, which in turn causes errors in the measurement of the distance of the target to be measured determined by the photon flight time. In this regard, the embodiment of the present disclosure can obtain a calibration error, determine the time difference between the start time of the detected light pulse and the start time of the emission light pulse, and then determine the distance of the target to be measured based on the calibration error and the time difference.

[0134] Among them, the calibration error can be a time calibration error or a distance calibration error. The calibration error can be determined by the ranging device based on historical experiments, or it can be sent by other electronic devices, and the present disclosure is not limited. The calibration process of the embodiment of the present disclosure can be to set the target to be measured at multiple known distances (assuming 10 meters, 15 meters, etc.), the laser transmitter emits a laser and is detected by the SPAD after being reflected by the target to be measured, and the distances solved in the histogram are 10.05 meters and 15.05 meters respectively, so that the distance calibration error can be determined to be 0.05 meters, and this calibration error can be regarded as a measurement error caused by signal transmission delay. When the actual measurement is performed later, the measurement result is compensated with the calibration error, and an accurate ranging result with reduced measurement error caused by signal transmission delay can be obtained. Correspondingly, based on the distance calibration error and the speed of light constant, the time calibration error can be determined.

[0135] If the calibration error is a time calibration error, the duration between the start time of the detected light pulse and the start time of the emitted light pulse determined by the above method can be compensated by the calibration error to be determined as the corrected photon flight time, and then the distance of the target to be measured can be determined based on the photon flight time method.

[0136] If the calibration error is a distance calibration error, the distance can be calculated based on the photon flight time method by taking the time between the start time of the detected light pulse and the start time of the emitted light pulse as the photon flight time, and the distance is compensated by the calibration error to be determined as the distance of the target to be measured. Through this solution, the influence of the error in determining the start time of the emitted light pulse on the distance measurement result can be reduced, and the accuracy of determining the distance of the target to be measured can be improved.

[0137] Fig.12 A reflectivity correction ToF ranging method process provided in the embodiment of the present disclosure Figure 2 , the method comprises the following steps:

[0138] S1001, histogram filtering;

[0139] In the disclosed embodiment, the distance measuring device filters the statistical results of the photon flight time of the light pulse reflected by the target to be measured, such as smoothing filtering, mean filtering, etc., to reduce the influence of light noise, etc. The statistical results include the detection time of the photon and the number of photons corresponding to the detection time.

[0140] S1002, finding the peak center;

[0141] In the embodiment of the present disclosure, the peak center corresponds to the aforementioned distribution center; the ranging device of the embodiment of the present disclosure determines the peak center of the number of photons at the detection time based on the statistical results after filtering. For example, the detection time corresponding to the highest peak in the histogram can be determined as the peak center of the number of photons at the detection time; or the statistical results after filtering are processed using a centroid algorithm to determine the centroid of the histogram, and the detection time corresponding to the centroid is determined as the peak center of the number of photons at the detection time.

[0142] S1003, calculating peak broadening;

[0143] In the embodiment of the present disclosure, the peak broadening corresponds to the aforementioned concentration; the distance measuring device of the embodiment of the present disclosure determines the peak broadening of the number of photons at the detection time based on the statistical results after filtering. For example, one of the weighted value of the peak broadening of the statistical results in the histogram, the half-height width, the correlation value of the standard deviation, and the correlation value of the quartile is determined as the peak broadening of the number of photons at the detection time.

[0144] S1004. Calculate the peak starting point according to the peak center and the peak width.

[0145] In the disclosed embodiment, the distance measuring device determines the peak starting point position as the time obtained by subtracting the peak width from the peak center based on the peak center and the peak width, that is, the start time of the aforementioned detected light pulse.

[0146] Fig.13 An example diagram of a reflectivity-corrected ToF distance measurement device provided by an embodiment of the present disclosure is shown. Fig.13 It is known that, including:

[0147] A single photon response module 1101 is used to respond to detection photons; wherein the photons include photons after the light pulse is reflected by the target to be detected;

[0148] A time information module 1102, used to obtain the detection time of the photons of the light pulse;

[0149] The counting module 1103 is used to count and count the detected photons to obtain statistical results; wherein the statistical results include the detection time of the photons and the number of photons corresponding to the detection time;

[0150] The data processing module 1104 is used to determine the start time of detecting the light pulse according to the statistical results; and determine the distance of the target to be measured according to the start time of detecting the light pulse and the start time of emitting the light pulse.

[0151] In some embodiments, the data processing module 1104 is used to determine the distribution center and concentration of the number of photons at the detection time based on the statistical results; and determine the start time of the detected light pulse based on the distribution center and concentration of the number of photons at the detection time.

[0152] In some embodiments, the aggregation degree includes: one of a weighted value of peak broadening, a half-height width, a correlation value of a standard deviation, and a correlation value of a quartile of the statistical result in a histogram;

[0153] The relevant value of the standard deviation refers to the length of the time interval corresponding to the integer multiple standard deviation or non-integer multiple standard deviation of the statistical result in the histogram;

[0154] The quartile correlation value refers to the length of the time interval corresponding to any two quartiles of the statistical result in the histogram.

[0155] In some embodiments, the data processing module 1104 is used to subtract the concentration from the distribution center of the number of photons at the detection time to determine the start time of the detection of the photons.

[0156] In some embodiments, the standard deviation is a distribution standard deviation or a mapping standard deviation;

[0157] The distribution standard deviation refers to the standard deviation reflecting the distribution of the number of photons over the detection time;

[0158] The mapping standard deviation refers to a standard deviation determined by the number of photons according to a preset mapping relationship.

[0159] In some embodiments, the start time of emitting the light pulse includes:

[0160] One of the generation time of the control signal, the reception time of the control signal or the actual emission time of the light pulse; wherein the control signal is a signal for controlling the emission of the light pulse.

[0161] In some embodiments, the data processing module 1104 is used to obtain a compensation coefficient related to the concentration, and use the compensation coefficient to compensate for the concentration; the distribution center of the number of photons at the detection time minus the compensated concentration is subtracted to determine the start time of the detected light pulse.

[0162] In some embodiments, the data processing module 1104 is used to obtain a calibration error; determine the time difference between the start time of detecting the light pulse and the start time of emitting the light pulse; and determine the distance of the target to be measured based on the calibration error and the time difference.

[0163] Fig.14 A reflectivity-corrected ToF ranging device is shown in an embodiment of the present disclosure, comprising Fig.14 It is known that, including:

[0164] The single-photon avalanche diode pixel 1201 is used to respond to the detection photon; wherein the single-photon avalanche diode pixel corresponds to the SPAD in the aforementioned single-photon avalanche diode array.

[0165] A time-to-digital converter 1202, used to obtain the detection time of the photons of the light pulse;

[0166] The counter 1203 is used to count and calculate the detected photons to obtain statistical results; wherein the statistical results include the detection time of the photons and the number of photons corresponding to the detection time;

[0167] The central processor 1204 is used to determine the start time of detecting the light pulse according to the statistical result; and determine the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse.

[0168] The photons include photons after the light pulse is reflected by the target to be measured; if the SPAD detects the photons, a pulse signal is generated, and if the SPAD does not detect the photons, no pulse signal is generated.

[0169] The central processor 1204 of the embodiment of the present disclosure is a circuit including devices such as a central processing unit (CPU), a microcontroller unit (MCU), etc.

[0170] In some embodiments, the central processor 1204 is used to determine the distribution center and concentration of the number of photons at the detection time based on the statistical results; and determine the start time of the detected light pulse based on the distribution center and concentration of the number of photons at the detection time.

[0171] In some embodiments, the aggregation degree includes: one of a weighted value of peak broadening, a half-height width, a correlation value of a standard deviation, and a correlation value of a quartile of the statistical result in a histogram;

[0172] The relevant value of the standard deviation refers to the length of the time interval corresponding to the integer multiple standard deviation or non-integer multiple standard deviation of the statistical result in the histogram;

[0173] The quartile correlation value refers to the length of the time interval corresponding to any two quartiles of the statistical result in the histogram.

[0174] In some embodiments, the central processor 1204 is used to subtract the concentration from the distribution center of the number of photons at the detection time to determine the start time of the detection of the photons.

[0175] In some embodiments, the standard deviation is a distribution standard deviation or a mapping standard deviation;

[0176] The distribution standard deviation refers to the standard deviation reflecting the distribution of the number of photons over the detection time;

[0177] The mapping standard deviation refers to a standard deviation determined by the number of photons according to a preset mapping relationship.

[0178] In some embodiments, the start time of emitting the light pulse includes:

[0179] One of the generation time of the control signal, the reception time of the control signal or the actual emission time of the light pulse; wherein the control signal is a signal for controlling the emission of the light pulse.

[0180] In some embodiments, the central processor 1204 is used to obtain a compensation coefficient related to the concentration, and use the compensation coefficient to compensate for the concentration; the distribution center of the number of photons at the detection time minus the compensated concentration is subtracted to determine the start time of the detected light pulse.

[0181] In some embodiments, the central processor 1204 is used to obtain a calibration error; determine the time difference between the start time of detecting the light pulse and the start time of emitting the light pulse; and determine the distance of the target to be measured based on the calibration error and the time difference.

[0182] Correspondingly, an embodiment of the present disclosure provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, part or all of the steps in the above method are implemented.

[0183] It should be noted that the description of the above storage medium and device embodiments is similar to the description of the above method embodiments, and has similar beneficial effects as the method embodiments. For technical details not disclosed in the storage medium and device embodiments of the present disclosure, please refer to the description of the method embodiments of the present disclosure for understanding.

[0184] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial number of the above-mentioned processes does not mean 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 the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.

[0185] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0186] In the several embodiments provided in the present disclosure, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0187] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0188] In addition, all functional units in the embodiments of the present disclosure may be integrated into one processing unit, or each unit may be separately configured as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0189] A person skilled in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the aforementioned storage medium includes: mobile storage devices, read-only memories (ROM), magnetic disks or optical disks, etc., various media that can store program codes.

[0190] Alternatively, if the above-mentioned integrated unit of the present disclosure is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present disclosure can essentially or in other words, the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in each embodiment of the present disclosure. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0191] The above is only an embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A reflectivity-corrected ToF ranging method, characterized in that: The method comprises: Obtaining a statistical result of the photon flight time of the light pulse reflected by the target to be measured; wherein the statistical result includes the detection time of the photon and the number of photons corresponding to the detection time; Determining the start time of detecting the light pulse according to the statistical results; The distance of the target to be detected is determined according to the start time of detecting the light pulse and the start time of emitting the light pulse.

2. The method according to claim 1, characterized in that: Determining the start time of detecting the light pulse according to the statistical result includes: According to the statistical results, determining the distribution center and concentration of the number of photons at the detection time; The start time of the detected light pulse is determined according to the distribution center and concentration of the number of photons at the detection time.

3. The method according to claim 2, characterized in that The aggregation degree includes: one of the weighted value of the peak width, the half-height width, the correlation value of the standard deviation, and the correlation value of the quartile of the statistical result in the histogram; The relevant value of the standard deviation refers to the length of the time interval corresponding to the integer multiple standard deviation or non-integer multiple standard deviation of the statistical result in the histogram; The quartile correlation value refers to the length of the time interval corresponding to any two quartiles of the statistical result in the histogram.

4. The method according to claim 3, characterized in that Determining the start time of detecting the light pulse according to the distribution center and concentration of the number of photons at the detection time includes: The starting time of detecting the photons is determined by subtracting the concentration degree from the distribution center of the photon quantity at the detection time.

5. The method according to claim 3, characterized in that: The standard deviation is a distribution standard deviation or a mapping standard deviation; The distribution standard deviation refers to the standard deviation reflecting the distribution of the number of photons over the detection time; The mapping standard deviation refers to a standard deviation determined by the number of photons according to a preset mapping relationship.

6. The method according to claim 1, characterized in that The starting time of emitting the light pulse includes: One of the generation time of the control signal, the reception time of the control signal or the actual emission time of the light pulse; wherein the control signal is a signal for controlling the emission of the light pulse.

7. The method according to claim 2 or 3, characterized in that: Determining the start time of the detected light pulse according to the distribution center and concentration of the number of photons at the detection time includes: Acquire a compensation coefficient related to the concentration, and use the compensation coefficient to compensate for the concentration; The distribution center of the photon quantity at the detection time minus the compensated concentration is determined as the start time of the detected light pulse.

8. The method according to claim 1, characterized in that Determining the distance of the target to be measured according to the start time of detecting the light pulse and the start time of emitting the light pulse includes: Get the calibration error; Determining a time difference between a start time of detecting the light pulse and a start time of emitting the light pulse; The distance of the target to be measured is determined according to the calibration error and the time difference.

9. A reflectivity-corrected ToF ranging device, characterized in that: The device comprises: A single photon response module, used to respond to detection photons; wherein the photons include photons after the light pulse is reflected by the target to be detected; A time information module, used to obtain the detection time of the photons of the light pulse; A counting module, used to count and count the detected photons to obtain statistical results; wherein the statistical results include the detection time of the photons and the number of photons corresponding to the detection time; The data processing module is used to determine the start time of detecting the light pulse according to the statistical results; and to determine the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse.

10. A reflectivity-corrected ToF ranging device, characterized in that: The device comprises: A single photon avalanche diode pixel, for responding to a detection photon; wherein the photon comprises a photon after a light pulse is reflected by a target to be detected; A time-to-digital converter, used to obtain the detection time of the photons of the light pulse; A counter, used to count and calculate the detected photons to obtain a statistical result; wherein the statistical result includes the detection time of the photons and the number of photons corresponding to the detection time; The central processing unit is used to determine the start time of detecting the light pulse according to the statistical result; and determine the distance of the target to be detected according to the start time of detecting the light pulse and the start time of emitting the light pulse.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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