WO2023279618A1 - Distance measurement system, and method for shielding fuzzy distance value - Google Patents

Abstract

A distance measurement system and a method for shielding a fuzzy distance value. The distance measurement system comprises: an emitter (11) configured to emit a signal beam of which a pulse period is first time towards an object to be measured; a collector (12) configured to collect part of the signal beam reflected back by said object and output a photon signal, wherein the effective working time of the collector (12) is second time, and the second time is less than the first time; a processing circuit (13) connected to the emitter (11) and the collector (12), and configured to calculate a target distance value of said object according to the photon signal, determine the target distance value as a fuzzy distance value according to the photon signal and a resolution threshold or according to the photon signal and a signal photon number threshold, and then shielding the fuzzy distance value. According to the method and system, the measurement frame rate is improved while the problem of fuzzy distance measurement is solved in single-frequency distance measurement.

Description

A distance measurement system and method for shielding fuzzy distance values

This application claims the priority of the Chinese patent application with the application number 202110769042.1 filed on July 7, 2021, entitled "A distance measurement system and method for shielding fuzzy distance values", the entire contents of which are incorporated by reference incorporated in this application.

technical field

The invention relates to the field of optical technology, in particular to a distance measurement system and a method for shielding fuzzy distance values.

Background technique

For a distance measurement system based on the Time-of-flight (TOF) principle, the formula for calculating the distance is:

Wherein, c is the speed of light, about 3×10 ⁸ m/s, f is the modulation frequency of the emitted light signal, and k is a positive integer, representing the number of integer periods. If only one modulation frequency is used for distance measurement, the system usually defaults to k=0 in one measurement. When the reflected light signal collected by the collector comes from the measured target outside the maximum range corresponding to the modulation frequency, it cannot be confirmed The real distance of the measured target is in the distance period, that is, the k value cannot be confirmed, and the measured distance of the measured target is much smaller than the real distance. This phenomenon is called the distance ambiguity phenomenon of TOF ranging. When the modulation frequency is f, the distance value corresponding to an integer number of cycles is called the fuzzy distance corresponding to the distance value at the current modulation frequency.

The existing methods to solve TOF distance ambiguity mainly include dual-frequency ranging to solve distance aliasing. Dual-frequency ranging means to use two different frequencies to measure the same measured target, and determine the real distance through the two measurement results. . However, in the dual-frequency ranging method, the distance value of each target point needs to be continuously measured twice using two different frequencies, which will greatly reduce the measurement frame rate. However, the traditional TOF ranging method uses a single frequency to measure the distance, and there will be a problem of ranging ambiguity. Therefore, how to solve the ranging blur problem without reducing the system frame rate is an urgent problem to be solved.

Contents of the invention

In order to overcome the problems in the prior art, an embodiment of the present invention provides a distance measurement system and a method for shielding fuzzy distance values.

In order to achieve the above purpose, the technical solution of the embodiment of the present invention is achieved as follows: In the first aspect, an embodiment of the present invention provides a distance measurement system, including:

a transmitter configured to emit a signal beam whose pulse period is the first time toward the object to be measured;

A collector configured to collect part of the signal light beam reflected back by the object to be measured and output a photon signal, wherein the effective working time of the collector is a second time, and the second time is shorter than the first time;

A processing circuit connected to the emitter and the collector, the processing circuit calculates the target distance value of the object to be measured according to the photon signal, according to the photon signal and the resolution threshold, or according to the photon signal When the signal and the signal photon number threshold determine that the target distance value is a fuzzy distance value, the fuzzy distance value is masked.

In some embodiments, the collector includes a pixel unit, and the pixel unit includes a plurality of pixels, and the pixels are used to respond to and output a single photon in a part of the signal beam reflected back by the object to be measured said photon signal;

The collector also includes a readout circuit configured to output a histogram according to the photon signal;

The processing circuit is also used to calculate the number of ambient photons and the number of signal photons according to the histogram; if according to the number of ambient photons, the number of signal photons and the resolution threshold, or, according to the number of signal photons and a preset The threshold value of the number of signal photons determines that the target distance value is a fuzzy distance value, and then the fuzzy distance value is masked.

In some embodiments, the resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold; the variable resolution threshold is determined according to an average value of ambient light.

In some embodiments, the processing circuit calculates the target resolution of the object to be measured according to the number of signal photons and the number of ambient photons, if the target resolution is greater than the resolution threshold, or, the If the target resolution is greater than or equal to the resolution threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is shielded; or,

If the processing circuit determines that the number of signal photons is less than the threshold value of the number of signal photons, or that the number of signal photons is less than or equal to the threshold value of the number of signal photons, then determine that the target distance value is an ambiguous distance value, and shield the Blur distance value.

In some embodiments, the target resolution of the object to be measured is calculated according to the following first function model or second function model,

The first function model is:

The second function model is:

Among them, C _s is the number of signal photons; C _n is the number of environmental photons; a, b, c, d, e are all parameters; _f is the focal length of the lens of the collector; Resolution is the target resolution.

In some embodiments, the processing circuit determines a first ranging range and a second ranging range according to the first time and the second time; acquires a first resolution range corresponding to the first ranging range , a second resolution range corresponding to the second ranging range; determining the preset quantitative resolution threshold according to the first resolution range and the second resolution range.

In some embodiments, the processing circuit calculates the mean value of the ambient light intensity according to the number of signal photons and the number of ambient photons; determines the variable resolution threshold according to the mean value of the ambient light level and a preset fitting function relationship, so The preset fitting function relationship includes the relationship between the variable resolution threshold and the average value of ambient light intensity.

In some embodiments, the processing circuit obtains the number of signal photons and the number of environmental photons corresponding to different initial sampling points, and calculates the sampling resolution of each initial sampling point according to the number of signal photons and the number of environmental photons; if any The sampling resolution of an initial sampling point is less than the preset sampling resolution threshold, or, the sampling resolution is less than or equal to the preset sampling resolution threshold, then mark the initial sampling point as the target sampling point; according to the Calculate the mean value of the ambient light intensity from the number of signal photons and the number of ambient photons at the target sampling point.

In some embodiments, the processing circuit calculates the reflectance corresponding to each of the target sampling points according to the number of signal photons of each of the target sampling points and the pre-stored reflectance calculation rules; according to each of the target sampling points The number of ambient photons, the corresponding reflectivity, and the calculation rules of the pre-stored ambient light irradiance, calculate the sampling ambient light irradiance corresponding to each of the target sampling points; The sampled ambient light irradiance is used to calculate the sampled ambient illuminance corresponding to each of the target sampling points, and the average value of the ambient illuminance is calculated according to the sampled ambient illuminance corresponding to each of the target sampling points.

In some embodiments, the pre-stored reflectance calculation rule is:

Among them, Re is the reflectivity of the measured object at any target sampling point; C _ns is the number of signal photons at the target sampling point; TCSPC is the number of transmitted pulses in the prior single-frame measurement; θ is the incident angle of light; L is the measurement distance of the measured object; P _t is the peak power of the signal beam emitted by the light source; k ₁ is the first preset coefficient.

In some embodiments, the calculation rule of the pre-stored ambient light irradiance is:

Among them, I _AL is the ambient light irradiance of any target sampling point; C _ns is the number of signal photons of the target sampling point; C _nn is the number of ambient photons of the target sampling point; θ is the incident angle of light; The measurement distance of the measured object; _f represents the lens focal length of the collector; k ₂ is the second preset coefficient, and k ₃ is the third preset coefficient.

In the second aspect, an embodiment of the present invention provides a method for masking fuzzy distance values, including:

Acquiring a photon signal corresponding to the signal beam reflected by the object to be measured; wherein, the emission pulse period of the signal beam is a first time, and the effective collection time of the signal beam is a second time, and the second time is shorter than the first time a time;

calculating a target distance value of the object to be measured according to the photon signal;

When the target distance value is determined to be an ambiguous distance value according to the photon signal and the resolution threshold, or according to the photon signal and the signal photon number threshold, the ambiguous distance value is masked.

In some embodiments, when the target distance value is determined to be an ambiguous distance value according to the photon signal and the resolution threshold, or according to the photon signal and the signal photon number threshold, masking the ambiguous distance value includes:

Acquiring the number of signal photons and the number of photons in the environment; the number of photons in the signal and the number of photons in the environment are determined according to the photon signal;

If the target distance value is determined to be a fuzzy distance value according to the number of ambient photons, the number of signal photons and the resolution threshold, or, according to the number of signal photons and the preset threshold of photon numbers of signals, then mask the fuzzy distance value .

In some embodiments, if the target distance value is determined according to the ambient photon number, the signal photon number and the resolution threshold, or according to the signal photon number and the preset signal photon number threshold, the fuzzy distance value, mask the fuzzy distance value, including:

Calculate the target resolution of the object to be measured according to the number of signal photons and the number of environmental photons; if the target resolution is greater than a resolution threshold, or, the target resolution is greater than or equal to the resolution threshold, Then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value; or,

If it is determined that the number of signal photons is less than the threshold value of the number of signal photons, or the number of signal photons is less than or equal to the threshold value of the number of signal photons, then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value.

In some embodiments, the resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold; the variable resolution threshold is determined according to an average value of ambient light.

Compared with the prior art, the present invention shields the ambiguous ranging value of the ranging system based on the resolution threshold or the signal photon number threshold, realizes single-frequency ranging and improves the measurement frame rate while solving ranging ambiguity.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

For better understanding and implementation, the present invention will be described in detail below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a schematic diagram of a distance measuring system shown in an exemplary embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for shielding fuzzy distance values in a distance measurement system according to an exemplary embodiment of the present invention;

Fig. 3 is a schematic structural diagram of a device for masking fuzzy distance values according to an exemplary embodiment of the present invention;

Fig. 4 is a schematic diagram of a device for masking fuzzy distance values provided by an exemplary embodiment of the present invention.

detailed description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with aspects of the invention as recited in the appended claims.

The terminology used in the present invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein and in the appended claims, the singular forms "a", "the", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

FIG. 1 is a schematic diagram of a distance measurement system provided by an exemplary embodiment. The distance measurement system 10 includes a transmitter 11 , a collector 12 and a processing circuit 13 . Wherein, the emitter 11 is used to emit a light beam 300 to the target area 200, and the light beam is emitted into the space of the target area to illuminate the target object in the space, at least part of the emitted light beam 300 is reflected by the target area 200 to form a reflected light beam 400, and the reflected light beam 400 At least part of the light beam in the light beam is received by the collector 12; the processing circuit 13 is respectively connected with the transmitter 11 and the collector 12, and the trigger signal of the synchronous transmitter 11 and the collector 12 is used to calculate the time required for the light beam to be received from being emitted to being reflected back , that is, the flight time t between the emitted beam 300 and the reflected beam 400, further, the distance D of the corresponding point on the target object can be calculated by the following formula:

D＝c·t/2

where c is the speed of light.

Specifically, the emitter 11 includes a light source 111, an emitting optical element 112, a driver 113, and the like. Wherein, the light source 111 may be a light-emitting diode (LED), a laser diode (LD), an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), etc., or a one-dimensional or two-dimensional light source composed of multiple light sources. Array; preferably, the light source array is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate, and the arrangement of the light sources in the light source array can be regular or irregular. The light beam emitted by the light source 111 may be visible light, infrared light, ultraviolet light, and the like. The light source 111 emits light beams outward under the control of the driver 113 . In one embodiment, the light source 111 emits a pulsed beam at a certain frequency (pulse period) under the control of the driver 113, which can be used in direct time-of-flight (Direct TOF) measurement, and the frequency is set according to the measurement distance. It can be understood that a part of the processing circuit 13 or a sub-circuit independent of the processing circuit 13 may also be used to control the light source 111 to emit light beams.

The emitting optical element 112 receives and shapes the light beam emitted from the light source 111 and projects it to a target area. In one embodiment, the transmitting optical element 112 receives the pulsed beam from the light source 111, and optically modulates the pulsed beam, such as modulation such as diffraction, refraction, reflection, etc., and then emits the modulated beam into space, such as a focused beam, Flood beam, structured light beam, etc. The emitting optical element 112 may be one or a combination of lenses, liquid crystal elements, diffractive optical elements, microlens arrays, metasurface optical elements, masks, reflectors, MEMS vibrating mirrors, and the like.

The collector 12 includes a pixel unit 121, a filter unit 122 and a receiving optical element 123; wherein the receiving optical element 123 is used to receive at least part of the light beam reflected back by the target and guide it to the pixel unit 121; the filter unit 122 is used to filter out the background light or stray light. The pixel unit 121 includes a two-dimensional pixel array composed of a plurality of pixels. In one embodiment, the pixel unit 121 is a pixel array composed of a single photon avalanche photodiode (SPAD). The SPAD can respond to an incident single photon and output The signal indicating the corresponding arrival time of the received photons at each SPAD is used, such as time-correlated single photon counting (TCSPC), to realize the collection of weak light signals and the calculation of flight time. Generally, the pixel unit 121 is connected to a readout circuit composed of one or more of signal amplifiers, time-to-digital converters (TDC), digital-to-analog converters (ADC) and other devices (not shown in the figure). . These circuits can be integrated with the pixel unit 121 as a part of the collector 12 or as a part of the processing circuit 13 .

The processing circuit 13 synchronizes the trigger signals of the emitter 11 and the collector 12, processes the photon signal of the pixel collection beam, and calculates the distance information of the target object to be measured based on the time-of-flight of the reflected beam. In one embodiment, the SPAD outputs a photon signal in response to an incident single photon, and the processing circuit 13 receives the photon signal and performs signal processing to obtain the time-of-flight of the light beam.

Specifically, the processing circuit 13 counts the number of collected photons to form continuous time bins (denoted as the unit time of the collector sampling), and these time bins are connected together to form a statistical histogram, which is used to reproduce the time sequence of the reflected beam. Peak matching and filter detection identify the time-of-flight of the reflected beam from emission to reception.

In the embodiment of the present invention, the transmitter is configured to emit a signal beam with a pulse period of the first time towards the object to be measured; the collector is configured to collect part of the signal beam reflected back by the object to be measured and output a photon signal, wherein the acquisition The effective working time of the device is the second time, and the second time is less than the first time;

A processing circuit connected to the transmitter and the collector, calculating the target distance value of the object to be measured according to the electrical signal, and determining whether the target distance value is a fuzzy distance value according to the target distance value and a preset threshold value, And mask the fuzzy distance value.

Wherein, the distance measurement system stores a preset threshold in advance, and the preset threshold may be a resolution threshold or a signal photon number threshold, which is not limited here. The processing circuit determines whether the target distance value is a fuzzy distance value according to the target distance value and a preset threshold value, and if the target distance value is a fuzzy distance value, the fuzzy distance value is masked.

In some embodiments, the collector includes a readout circuit, and the readout circuit includes a TDC circuit and a histogram circuit, wherein the TDC circuit is used to receive and calculate the time-of-flight information of the photon, and convert the time-of-flight information into a time code; The code is input into the histogram circuit to address the corresponding time bin (recorded as the unit time of the collector sampling), and to increase the photon count value in the corresponding time bin. The count value draws a statistical histogram, which includes continuous time intervals (time bin) in the statistical histogram. The abscissa of the histogram represents the flight time, and the ordinate represents the photon count value. / or signal photons. The processing circuit calculates the number of environmental photons and the number of signal photons according to the histogram output by the histogram circuit; among them, the number of signal photons is the sampling signal, which is the number of photons in the signal beam reflected by the measured object collected by the collector, and the number of environmental photons is Environmental data, the number of environmental photons is the number of environmental photons collected at the same time when the collector collects photons in the signal beam reflected by the measured object. Specifically, the local area is intercepted from the histogram to calculate the average value of the ambient photon number, and the local area far away from the pulse peak position is selected according to the pulse peak position in the histogram to calculate the ambient photon number average value. In an optional embodiment, the average value of the number of ambient photons can also be calculated according to all the time intervals of the histogram, and the sum of the photon numbers in all time intervals is removed from the sum of the photon numbers at the peak position of the pulse and then averaged to obtain the number of ambient photons Mean value, the mean value of the number of ambient photons is the number of ambient photons included in each time interval in the histogram. And, according to the pulse peak position and the pulse width, the pulse region is intercepted from the histogram to calculate the sum of the photon number in this region and the ambient photon number, and further calculate the signal photon number. In some other embodiments, other methods may also be used to calculate the number of ambient photons and the number of signal photons, which are not specifically limited in the present invention.

Assuming that the maximum measurement range of the distance measurement system is D, the pulse period is usually set as time T, T=2D _/ c. In system design, the working time of the TDC circuit corresponds to T, and the number of time bins configured in the histogram circuit is based on T design. In the embodiment of the present invention, the pulse period of the modulated emitted light pulse is a first time T1, and the modulated collector collects reflected light signals within a second time T2 shorter than the first time T1. Among them, in the time period of T1-T2, the TDC circuit is in the reset state, no longer counting, then the effective working time of the collector is the second time T2, and the effective working time of the TDC is also the second time T2, then the histogram The number of time bins in the circuit configuration is designed according to the second time T2.

Take T1=125ns as an example to illustrate, assuming T1=125ns, the corresponding range is 18.75m, set T2=66.66ns, the corresponding range is 10m, then for the target between 10m and 18.75m, the collector The reflected light signal cannot be collected. If the target is between 18.75m and 28.75m and the reflected light signal can be collected by the collector, distance ambiguity may occur, that is, the distance value measured by the ranging system is still within the range of 0 to 10m.

When the pulse period is set as T1=125ns, the number of time-correlated single-photon counting (Time-correlated single-photon counting, TCSPC) is determined as:

The total number of TCSPC is about 64000.

In order to improve the signal-to-noise ratio, in one embodiment, n pulses can be emitted in each pulse period to form a group of pulse trains, and the interval between pulses is randomly configured, for example, it can be set as t1, t2, ... tn, and t1 +t2+...+tn=T1, the number of equivalent TCSPCs is 64000*n, and n is the number of pulse beams in one cycle.

In an optional embodiment, it may be determined whether the object to be measured is within the distance measurement range by preset quantitative resolution threshold. Specifically, the system obtains the number of signal photons and the number of environmental photons, and then calculates the target resolution of the object to be measured according to the number of signal photons and the number of environmental photons; if the target resolution is greater than, or greater than or equal to the preset quantitative resolution threshold, then Determine the target distance value as the fuzzy distance value, and shield the fuzzy distance value.

In an embodiment, the preset quantitative resolution threshold may be preset with reference to the following manner.

Wherein, the emission pulse period of the signal beam is the first time; the effective collection time of the signal beam is the second time; the second time is less than the first time; the first ranging range and the second measuring range are determined according to the first time and the second time range; obtain the first resolution range corresponding to the first ranging range, and the second resolution range corresponding to the second ranging range; determine the preset quantitative resolution according to the first resolution range and the second resolution range threshold.

Specifically, for the problem of distance ambiguity, take T1=125ns as an example, since the ranging range corresponding to the modulation pulse period is 18.75m, and at the same time, the collector is controlled to only receive the reflected light signal of the target within the first 10m range. Then, the range corresponding to the next period in which the next range fuzzy signal is generated is 18.75 to 28.75 m.

In order to avoid the ranging signal from 18.75 to 28.75m in the next cycle from interfering with the normal ranging accuracy of 0 to 10m, measure the objects to be measured in the first ranging range of 0 to 10m and the second ranging range of 18.75 to 28.75m The distribution of resolutions under different peak power, incident angle, ambient light, and reflectivity within the range, focusing on comparing the resolutions in the first ranging range of 0 to 10m and the second ranging range of 18.75 to 28.75m. Among them, for the object to be measured at a certain preset distance, it is necessary to continuously measure n times and calculate the variance of the distance value of n times as the resolution, and adjust the peak power, incident angle, ambient light, reflectivity and other parameters to be different, repeat The above sampling process obtains multiple sets of calibration data. It is understandable that only one of the influencing parameters can be adjusted or multiple parameters can be adjusted at the same time. The size of the parameters can be adjusted randomly by using the mode of generating random numbers, or the size of the parameters can be adjusted according to certain rules, such as from small to large or The adjustment mode from large to small, the specific adjustment method is not limited in this application.

When the measured object has different reflectivity and the ambient light intensity is different, the resolution of the two ranging ranges from 0 to 10m and 18.75 to 28.75m has a large gap, and as the ambient light increases, the two The overlapping resolution in the scope is getting smaller and smaller. Through a large amount of measurement data fitting, it is determined that the resolution distribution within the range of 0 to 10m is the first resolution range [0, R ₁ ], and the resolution distribution within the range of 18.75 to 28.75m is the second resolution range [R ₂ , R ₃ ], and R ₂ ≤ R ₁ , so a fixed value R can be selected as the resolution threshold to shield the ranging blur, and R is usually set to a fixed value smaller than R ₂ .

During actual measurement, the system calculates the real-time target resolution, and compares the target resolution with the preset quantitative resolution threshold to mask the fuzzy distance value. Specifically, the distance measurement system calculates the number of ambient photons and the number of signal photons according to the histogram output by the histogram circuit, and calculates the target resolution according to the number of ambient photons, the number of signal photons and a preset resolution calculation rule. The system pre-stores preset resolution calculation rules, that is, the corresponding relationship between the number of ambient photons, the number of signal photons and the resolution, and calculates the target resolution according to the pre-stored resolution calculation rules.

In the embodiment of the present invention, there is no specific limitation on the preset resolution calculation rule. When the preset resolution calculation rule is a function model, it can be a function model in various forms. For example, the preset resolution calculation rule can be as follows Function model:

Among them, C _s is the number of signal photons; C _n is the number of environmental photons; a, b, c, d are all parameters; Resolution is the resolution.

As another example, the preset resolution calculation rule can also be the following function model:

Among them, C _s is the number of signal photons; C _n is the number of environmental photons; a, b, c, d, e are all parameters; _f is the focal length of the lens of the collector.

In order to obtain the calculation result of the resolution accurately, the function model of the calculation rule of the preset resolution can be obtained by fitting or training the sampled data.

The system judges the size between the target resolution and the preset quantitative resolution threshold. If the target resolution is greater than, or greater than or equal to the preset quantitative resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is blocked. . In the ranging process, the real-time target resolution R ₄ is calculated according to the real-time signal photon number and environmental photon number. If R ₄ >R, it indicates that the target distance value belongs to the fuzzy distance value and needs to be masked out.

Although the method of preset quantitative resolution masking solves the ranging ambiguity, the ranging range at the expense is too large, especially in the case of long-distance, high ambient light, and low reflectivity, the ranging range is greatly reduced.

In an optional embodiment, in order to overcome ranging ambiguity without sacrificing too much ranging range, it is possible to determine whether the object to be measured is within the ranging range by determining the variable resolution threshold, wherein the variable resolution threshold Determined according to the real-time ambient light average value. The device can obtain the number of signal photons and the number of environmental photons; calculate the target resolution of the object to be measured according to the number of signal photons and the number of environmental photons; calculate the average value of ambient light intensity according to the number of environmental photons and the number of signal photons; according to the calculated average value of ambient light intensity, and Determine the variable resolution threshold by fitting the function relationship between the preset variable resolution threshold and the average value of ambient light; if the target resolution is greater than, or greater than or equal to the determined variable resolution threshold, then determine the target distance as a fuzzy distance Value, masking blur distance value.

Specifically, the system obtains the number of signal photons and the number of ambient photons, and calculates the target resolution of the object under test according to the number of signal photons and the number of ambient photons.

The system obtains the number of signal photons and ambient photons corresponding to different initial sampling points, and calculates the sampling resolution of each initial sampling point according to the number of signal photons and ambient photons; if the sampling resolution is less than the preset sampling resolution threshold, or, sampling If the resolution is less than or equal to the preset sampling resolution threshold, the initial sampling point is marked as the target sampling point. That is, the initial sampling points whose sampling resolution is greater than, or greater than or equal to the preset sampling resolution threshold are masked out, and the rest of the initial sampling points are marked as target sampling points.

Then calculate the mean value of ambient light intensity according to the number of signal photons and the number of ambient light at the target sampling point; finally, according to the calculated mean value of ambient light intensity, the fitting function relationship between the preset variable resolution threshold and the mean value of ambient light intensity, determine the variable resolution threshold.

Among them, the sampling resolution of each initial sampling point can be calculated according to the preset resolution calculation rules provided above; the preset sampling resolution threshold can be set by referring to the setting method of the preset quantitative resolution threshold above. Let me repeat. The target sampling point is the sampling point that satisfies the preset quantitative resolution threshold constraint.

When calculating the average ambient light intensity based on the number of signal photons and ambient photons at target sampling points, first calculate the reflectance corresponding to each target sampling point according to the number of signal photons at each target sampling point and the pre-stored reflectance calculation rules; then, according to The number of ambient photons at each target sampling point, the corresponding reflectance, and the calculation rules of the pre-stored ambient light irradiance, calculate the sampling ambient light irradiance corresponding to each target sampling point; finally, according to the corresponding The ambient light irradiance is sampled to calculate the sampled ambient illuminance corresponding to each target sampling point, and the average value of the ambient illuminance is calculated according to the sampled ambient illuminance corresponding to each target sampling point.

In some embodiments, the reflectance calculation rule is pre-stored in the system, that is, the corresponding relationship between the number of signal photons and the reflectivity, and the reflectivity of the measured object is calculated according to the corresponding relationship between the number of signal photons and the reflectivity.

Wherein, the corresponding relationship between the number of signal photons and the reflectivity is obtained by derivation. The number of signal photons collected by the collector is not only affected by the reflectivity of the measured object, but also affected by factors such as the number of emitted pulses in a single frame measurement, the incident angle of light, the measurement distance of the measured object, and the peak power of the signal beam emitted by the light source. Therefore, the corresponding relationship between the number of signal photons and the reflectivity is calibrated when other factors are fixed, that is, the calculation rule of the reflectivity is deduced.

When the system calculates the reflectivity, it first obtains information such as the number of emitted pulses in the known single-frame measurement, the incident angle of light, the measurement distance of the measured object, and the peak power of the signal beam emitted by the light source. The reflectance calculation rule calculates the reflectance of the measured object.

In an optional embodiment, the pre-stored reflectance calculation rule may be:

Among them, Re is the reflectivity of the measured object at any target sampling point; C _ns is the number of signal photons at the target sampling point; TCSPC is the number of transmitted pulses in the prior single-frame measurement; θ is the incident angle of light; L is the measurement distance of the object under test; P _t is the peak power of the signal beam emitted by the light source; k ₁ is the first preset coefficient, which is a constant determined according to the system design, and the constant k ₁ will change for different system designs.

According to the aforementioned pre-stored reflectance calculation rules, the reflectance corresponding to each target sampling point can be calculated respectively. It can be understood that the correspondence between the number of signal photons and the reflectivity is not limited to the above relational expression, and the above relational expression does not specifically limit the correspondence between the number of signal photons and the reflectance.

In some embodiments, the system can calculate the sampled ambient light irradiance according to the number of ambient photons, the number of signal photons, the focal length of the lens of the collector, the incident angle of light, the reflectivity, and the pre-stored ambient light irradiance calculation rules.

In an optional embodiment, the pre-stored ambient light irradiance calculation rule is:

Among them, I _AL is the ambient light irradiance of any target sampling point; C _ns is the number of signal photons of the target sampling point; C _nn is the number of ambient photons of the target sampling point; θ is the incident angle of light; L is the measurement Distance; _f represents the lens focal length of the collector; k ₂ is the second preset coefficient, k ₃ is the third preset coefficient, the second preset coefficient and the third preset coefficient are constants determined according to the design of the system, different The system design constant will change.

According to the above-mentioned pre-stored ambient light irradiance calculation rules, the sampling ambient light irradiance calculation rules corresponding to each target sampling point can be calculated respectively. It can be understood that the pre-stored ambient light irradiance calculation rules are not limited to the above relational expressions, and the above-mentioned relational expressions do not specifically limit the pre-stored ambient light irradiance calculation rules.

In some embodiments, the system first calculates the sampled ambient light intensity corresponding to each target sampling point according to the sampled ambient light irradiance corresponding to each target sampling point, and then averages the sampled ambient light intensity corresponding to each target sampling point to obtain the average ambient light intensity .

In an optional embodiment, the sampled ambient illuminance of each target sampling point is first calculated according to the calculated sampled ambient light irradiance, specifically, the following formula can be used:

Wherein, E _i is the sampling ambient illuminance of the target sampling point i, I _AL is the sampling ambient light irradiance of the target sampling point i, i is the number of the target sampling point, i=1, 2, 3...n. n is the total number of target sampling points.

Then, average the sampled ambient illuminance values of n target sampling points satisfying the preset quantitative resolution threshold constraint, and obtain the ambient illuminance average value E:

It should be noted that, in this embodiment, the target sampling points use sequence numbers, and it should be understood that sequence numbers may not be used in other embodiments.

In some embodiments, the fitting function relationship between the variable resolution threshold and the average value of ambient light intensity can be specifically set in the following manner.

Construct the linear function relationship between the resolution threshold and the average value of the ambient light intensity: Resolution=aE+b, obtain the resolution threshold value of the blurred shielding distance under different ambient light conditions to obtain the calibration data of the average value of the ambient light intensity and the resolution threshold value of multiple groups, according to Calibration data determine the size of the coefficients a, b. In the actual distance measurement, the real-time variable resolution threshold Resolution can be determined according to the calculated average value E of the ambient light intensity.

In an optional embodiment, in order to avoid sacrificing the ranging range, a signal photon number threshold may be used to shield the ranging blur. The system acquires the real-time number of signal photons, and if the number of signal photons is less than, or less than or equal to, the threshold value of the number of signal photons, then the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is blocked.

Specifically, for the range ambiguity problem, since the ranging range corresponding to the modulated pulse period is 18.75m, at the same time, the collector is controlled to only receive the reflected light signal when the target is within the first 10m range. Then, the range corresponding to the next period in which the next range fuzzy signal is generated is 18.75 to 28.75 m.

In order to avoid the ranging signal from 18.75 to 28.75m in the next cycle from interfering with the normal ranging accuracy of 0 to 10m, measure the objects to be measured in the first ranging range of 0 to 10m and the second ranging range of 18.75 to 28.75m The resolution distribution under different peak power, incident angle, ambient light, and reflectivity within the range, where, for the object to be measured at a certain preset distance, it is necessary to measure n times continuously to calculate the variance of the distance value as the resolution , and adjust the peak power, incident angle, ambient light, reflectivity and other parameters are different, you can adjust the incident angle, ambient light intensity or reflectivity and other parameters, repeat the above sampling process to obtain multiple sets of calibration data. At the same time, the threshold value of the number of signal photons in the range of 0 to 10m and the range of 18.75m to 28.75m can be determined. Since the number of signal photons is inversely proportional to the square of the distance, the minimum number of signal photons within the range of 0 to 10m can be determined according to the calibration data and set as the threshold of the number of signal photons. When the real-time monitored signal photon number is less than the signal photon number threshold, the ranging value is invalid.

Please refer to FIG. 2. FIG. 2 is a schematic flow chart of a method for shielding fuzzy distance values according to an exemplary embodiment of the present invention. The method includes the following steps:

S201: Obtain a photon signal corresponding to the signal beam reflected by the object to be measured;

In the embodiment of the present invention, the signal beam is emitted by the transmitter, and the reflected light signal is reflected back by the object to be measured to be received by the collector, and a photon signal is output. Wherein, the emission pulse period of the signal beam is the first time (that is, the pulse period of the transmitter emitting the signal beam is the first time), and the effective collection time of the signal beam is the second time (the effective working time of the collector); The second time is less than the first time.

S202: Calculate the target distance value of the object to be measured according to the photon signal;

In the embodiment of the present invention, according to the histogram output by the histogram circuit, peak matching and filter detection are used to identify the time-of-flight of the signal beam from being emitted to being reflected back to being received, so as to calculate the target distance of the object to be measured.

S203: If the target distance value is determined to be an ambiguous distance value according to the photon signal and the resolution threshold, or according to the photon signal and the signal photon number threshold, mask the ambiguous distance value;

In the embodiment of the present invention, the resolution threshold may include a preset quantitative resolution threshold or a variable resolution threshold.

In an optional embodiment, it is judged whether the object to be measured is within the ranging range by preset quantitative resolution threshold, first obtain the number of signal photons and the number of environmental photons, and then calculate the number of photons to be measured according to the number of signal photons and the number of environmental photons The target resolution of the object; if the target resolution is greater than, or greater than or equal to the preset quantitative resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

In an optional embodiment, it is judged whether the object to be measured is within the distance measuring range by preset variable resolution threshold, first obtain the number of signal photons and the number of environmental photons, and then calculate the number of photons to be measured according to the number of signal photons and the number of environmental photons The target resolution of the object; if the target resolution is greater than, or greater than or equal to the preset variable resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

In an optional embodiment, the ranging ambiguity is shielded by the signal photon number threshold, and the signal photon number is obtained. If the signal photon number is less than, or less than or equal to the signal photon number threshold, the target distance value is determined to be the fuzzy distance value , mask the fuzzy distance value.

It should be noted that, in some embodiments, the method for shielding ambiguous distance values provided by the embodiments of the present invention can be implemented by using the distance measurement system in any of the foregoing embodiments. For details, please refer to the description in the embodiment of the distance measurement system , which will not be repeated here.

Compared with the prior art, the embodiment of the present invention obtains the electrical signal corresponding to the signal beam reflected by the object to be measured; calculates the target distance value of the object to be measured according to the electrical signal; if according to the target distance value and preset The threshold value determines that the target distance value is a fuzzy distance value, and then shields the fuzzy distance value. The present invention solves the problem of shielding the fuzzy distance measurement value of the distance measurement system based on the preset threshold value, realizes single-frequency distance measurement and resolves distance aliasing There is no need to reduce the measurement frame rate.

Please refer to FIG. 3 . FIG. 3 is a schematic structural diagram of a device for shielding ambiguous distance values of a distance measurement system according to an exemplary embodiment of the present invention. Each included unit is used to execute each step in the embodiment corresponding to FIG. 2 . For details, please refer to the relevant description in the embodiment corresponding to FIG. 2 . For ease of description, only the parts related to this embodiment are shown. Referring to Fig. 3, the device 3 of the fuzzy distance value of the shielding distance measurement system includes:

An acquisition unit 310, configured to acquire a photon signal corresponding to the signal beam reflected by the object to be measured;

a calculation unit 320, configured to calculate a target distance value of the object to be measured according to the photon signal;

The processing unit 330 is configured to mask the fuzzy distance value if the target distance value is determined to be a fuzzy distance value according to the photon signal and the resolution threshold, or according to the photon signal and the signal photon number threshold.

Further, the processing unit 330 is specifically configured to:

Acquiring the number of signal photons and the number of photons in the environment; the number of photons in the signal and the number of photons in the environment are determined according to the photon signal;

According to the number of ambient photons, the number of signal photons and the resolution threshold, or, according to the number of signal photons and the preset threshold of signal photons, the target distance value is determined to be a fuzzy distance value, and then the fuzzy distance value is masked.

Further, the emission pulse period of the signal beam is the first time; the effective collection time of the signal beam is the second time; the second time is less than the first time;

Further, the processing unit 330 is specifically configured to:

Calculate the target resolution of the object to be measured according to the number of signal photons and the number of environmental photons; if the target resolution is greater than a resolution threshold, or, the target resolution is greater than or equal to the resolution threshold, Then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value; or,

If it is determined that the number of signal photons is less than the threshold value of the number of signal photons, or the number of signal photons is less than or equal to the threshold value of the number of signal photons, then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value.

Please refer to FIG. 4 , which is a schematic diagram of a device for masking fuzzy distance values provided by an exemplary embodiment of the present invention. As shown in Figure 4, the device 4 for shielding the fuzzy distance value of this embodiment includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and operable on the processor 40, such as fuzzy Masker for distance values. When the processor 40 executes the computer program 42, the steps in the above embodiments of the method for masking blur distance values are implemented, for example, steps S201 to S203 shown in FIG. 2 . Alternatively, when the processor 40 executes the computer program 42, it realizes the functions of the modules/units in the above-mentioned device embodiments, for example, the functions of the units 310 to 330 shown in FIG. 3 .

Exemplarily, the computer program 42 can be divided into one or more modules/units, and the one or more modules/units are stored in the memory 41 and executed by the processor 40 to complete this invention. The one or more modules/units may be a series of computer program instruction segments capable of completing specific functions, and the instruction segments are used to describe the execution of the computer program 42 in the device 4 of the fuzzy distance value of the shielding distance measurement system process. For example, the computer program 42 can be divided into an acquisition module, a calculation module, and a processing module, and the functions of each module are as follows:

An acquisition module, configured to acquire an electrical signal corresponding to the signal beam reflected by the object to be measured;

a calculation module, configured to calculate the target distance value of the object to be measured according to the electrical signal;

A processing module, configured to mask the fuzzy distance value if the target distance value is determined to be a fuzzy distance value according to the photon signal and the resolution threshold, or according to the photon signal and the signal photon number threshold.

The device 4 for shielding distance measurement system fuzzy distance values may include, but not limited to, a processor 40 and a memory 41 . Those skilled in the art can understand that FIG. 4 is only an example of the device 4 for shielding fuzzy distance values, and does not constitute a limitation for the device 4 for shielding fuzzy distance values. It may include more or less components than those shown in the illustration, or combine them. Certain components, or different components, for example, the device 4 for shielding the fuzzy distance value of the distance measurement system may also include input and output devices, network access devices, buses, and the like.

The so-called processor 40 can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), Off-the-shelf programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like.

The memory 41 may be an internal storage unit of the device 4 for shielding fuzzy distance values, for example, a hard disk or a memory of the device 4 for shielding fuzzy distance values. Described memory 41 also can be the external storage device of the equipment 4 of described shielding fuzzy distance value, for example the plug-in type hard disk equipped on the equipment 4 of described shielding fuzzy distance value, smart memory card (Smart Media Card, SMC), Secure Digital (Secure Digital, SD) card, flash memory card (Flash Card), etc. Further, the memory 41 may also include both an internal storage unit of the device 4 for the fuzzy distance value of the shielded distance measurement system and an external storage device. The memory 41 is used to store the computer program and other programs and data required by the device for masking fuzzy distance values. The memory 41 can also be used to temporarily store data that has been output or will be output.

Those skilled in the art can clearly understand that for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units, Completion of modules means that the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into one processing unit, or each unit can exist separately physically, or two or more units can be integrated into one unit, and the above-mentioned integrated units can either adopt hardware It can also be implemented in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present application. For the specific working process of the units and modules in the above system, reference may be made to the corresponding process in the foregoing method embodiments, and details will not be repeated here.

In the above-mentioned embodiments, the descriptions of each embodiment have their own emphases, and for parts that are not detailed or recorded in a certain embodiment, refer to the relevant descriptions of other embodiments.

Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal equipment and method may be implemented in other ways. For example, the device/terminal device embodiments described above are only illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units Or components may be combined or may be integrated into another system, or some features may be omitted, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

If the integrated module/unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention realizes all or part of the processes in the methods of the above embodiments, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer When the program is executed by the processor, the steps in the above-mentioned various method embodiments can be realized. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (Read-Only Memory, ROM) , random access memory (Random Access Memory, RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, computer-readable media Excludes electrical carrier signals and telecommunication signals. The present invention is not limited to the above-mentioned embodiments, if the various changes or deformations of the present invention do not depart from the spirit and scope of the present invention, if these changes and deformations belong to the claims of the present invention and the equivalent technical scope, then the present invention is also It is intended that such modifications and variations are included.

Claims (14)

1. A distance measurement system, characterized in that it comprises:

   a transmitter configured to emit a signal beam whose pulse period is the first time toward the object to be measured;

   A collector configured to collect part of the signal light beam reflected back by the object to be measured and output a photon signal, wherein the effective working time of the collector is a second time, and the second time is shorter than the first time;

   A processing circuit connected to the emitter and the collector, the processing circuit calculates the target distance value of the object to be measured according to the photon signal, according to the photon signal and the resolution threshold, or according to the photon signal When the signal and the signal photon number threshold determine that the target distance value is a fuzzy distance value, the fuzzy distance value is masked.
2. The distance measuring system according to claim 1, wherein the collector includes a pixel unit, and the pixel unit includes a plurality of pixels, and the pixels are used for part of the signal reflected back from the object to be measured a single photon in the beam responds and outputs said photon signal;

   The collector also includes a readout circuit configured to output a histogram according to the photon signal;

   The processing circuit is also used to calculate the number of ambient photons and the number of signal photons according to the histogram; according to the number of ambient photons, the number of signal photons and a resolution threshold, or, according to the number of signal photons and a preset signal The photon number threshold determines that the target distance value is a fuzzy distance value, and then the fuzzy distance value is masked.
3. The distance measuring system according to claim 2, wherein the resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold; the variable resolution threshold is determined according to an average value of ambient light.
4. The distance measurement system according to claim 2 or 3, wherein the processing circuit calculates the target resolution of the object to be measured according to the number of signal photons and the number of photons in the environment, if the target resolution greater than the resolution threshold, or the target resolution is greater than or equal to the resolution threshold, then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value; or,

   If the processing circuit determines that the number of signal photons is less than the threshold value of the number of signal photons, or that the number of signal photons is less than or equal to the threshold value of the number of signal photons, then determine that the target distance value is an ambiguous distance value, and shield the Blur distance value.
5. The distance measurement system according to claim 4, wherein the target resolution of the object to be measured is calculated according to the following first function model or second function model,

   The first function model is:

   

   The second function model is:

   

   Among them, C _s is the number of signal photons; C _n is the number of environmental photons; a, b, c, d, e are all parameters; f is the focal length of the lens of the collector; Resolution is the target resolution.
6. The distance measuring system according to claim 3, wherein the processing circuit determines a first ranging range and a second ranging range according to the first time and the second time; The first resolution range corresponding to the distance range, and the second resolution range corresponding to the second ranging range; according to the first resolution range and the second resolution range, the preset quantitative resolution is determined threshold.
7. The distance measurement system according to claim 3, wherein the processing circuit calculates the mean value of ambient light intensity according to the number of signal photons and the number of ambient photons; The variable resolution threshold is determined, and the preset fitting function relationship includes a relationship between the variable resolution threshold and the average value of ambient light intensity.
8. The distance measurement system according to claim 7, wherein the processing circuit obtains the number of signal photons and the number of environmental photons corresponding to different initial sampling points, and calculates each initial photon number according to the number of signal photons and the number of environmental photons The sampling resolution of the sampling point; if the sampling resolution of any initial sampling point is less than the preset sampling resolution threshold, or if the sampling resolution is less than or equal to the preset sampling resolution threshold, then the initial sampling point Mark it as the target sampling point; calculate the average value of ambient light intensity according to the number of signal photons and the number of ambient photons at the target sampling point.
9. The distance measurement system according to claim 8, wherein the processing circuit calculates the reflectance corresponding to each target sampling point according to the number of signal photons at each target sampling point and a pre-stored reflectance calculation rule According to the number of ambient photons of each of the target sampling points, the corresponding reflectance, and the calculation rules of the pre-stored ambient light irradiance, calculate the sampling ambient light irradiance corresponding to each of the target sampling points; Calculate the sampled ambient illuminance corresponding to each target sampling point according to the sampled ambient light irradiance corresponding to each of the target sampling points, and calculate the mean value of the ambient illuminance according to the sampled ambient illuminance corresponding to each of the target sampling points.
10. The distance measurement system according to claim 9, wherein the pre-stored reflectance calculation rule is:

    

    Among them, Re is the reflectivity of the measured object at any target sampling point; C _ns is the number of signal photons at the target sampling point; TCSPC is the number of transmitted pulses in the prior single-frame measurement; θ is the incident angle of light; L is the measurement distance of the measured object; P _t is the peak power of the signal beam emitted by the light source; k ₁ is the first preset coefficient;

    The calculation rule of the pre-stored ambient light irradiance is:

    

    Among them, I _AL is the ambient light irradiance of any target sampling point; C _ns is the number of signal photons of the target sampling point; C _nn is the number of ambient photons of the target sampling point; θ is the incident angle of light; The measurement distance of the measured object; f represents the focal length of the lens of the collector; k ₂ is the second preset coefficient, and k ₃ is the third preset coefficient.
11. A method for shielding fuzzy distance values, comprising:

    Acquiring a photon signal corresponding to the signal beam reflected by the object to be measured; wherein, the emission pulse period of the signal beam is a first time, and the effective collection time of the signal beam is a second time, and the second time is shorter than the first time a time;

    calculating a target distance value of the object to be measured according to the photon signal;

    When the target distance value is determined to be an ambiguous distance value according to the photon signal and the resolution threshold, or according to the photon signal and the signal photon number threshold, the ambiguous distance value is masked.
12. The method for shielding fuzzy distance values according to claim 11, wherein the target distance value is determined to be fuzzy distance according to the photon signal and resolution threshold, or according to the photon signal and signal photon number threshold value, mask the fuzzy distance value, including:

    Acquiring the number of signal photons and the number of photons in the environment; the number of photons in the signal and the number of photons in the environment are determined according to the photon signal;

    If the target distance value is determined to be a fuzzy distance value according to the number of ambient photons, the number of signal photons and the resolution threshold, or, according to the number of signal photons and the preset threshold of photon numbers of signals, then mask the fuzzy distance value .
13. The method for shielding fuzzy distance values according to claim 12, wherein the method is based on the number of photons in the environment, the number of signal photons and the resolution threshold, or, based on the number of photons in the signal and a preset signal The photon number threshold determines that the target distance value is a fuzzy distance value, and then shields the fuzzy distance value, including:

    Calculate the target resolution of the object to be measured according to the number of signal photons and the number of environmental photons; if the target resolution is greater than a resolution threshold, or, the target resolution is greater than or equal to the resolution threshold, Then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value; or, if it is determined that the number of signal photons is less than the threshold value of the number of signal photons, or, the number of signal photons is less than or equal to the number of signal photons threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.
14. The method for shielding fuzzy distance values according to any one of claims 11 to 13, wherein the resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold; the variable resolution threshold is determined according to ambient light The mean is determined.

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