WO2023279619A1 - Itof ranging system, and method for shielding fuzzy distance value - Google Patents

Abstract

An ITOF ranging system, a method for shielding a fuzzy distance value, and a computer-readable storage medium. The ITOF ranging system (10) comprises: a transmitter (11), an acquisitor (12), and a processing circuit (13); the transmitter (11) is configured to transmit, to an object (20) to be measured, a signal beam (50) having a first frequency; the acquisitor (12) is configured to acquire a partial signal beam (50') reflected by said object and output a charge signal; and the processing circuit (13) is connected to the transmitter (11) and the acquisitor (12), and determines a target distance value as a fuzzy distance value according to the charge signal and a first threshold value, so as to shield the fuzzy distance value. According to the ranging system, the problem of shielding a fuzzy ranging value of the ranging system is solved on the basis of the first threshold value, thereby achieving single-frequency ranging, and improving the measurement of a frame rate.

Description

An ITOF ranging system and method for shielding fuzzy distance values

This application claims the priority of the Chinese patent application submitted to the China Patent Office on July 7, 2021 with the application number 202110769033.2. References are incorporated in this application.

technical field

The present application relates to the field of optical technology, in particular to an ITOF ranging system and a method for shielding fuzzy distance values.

Background technique

Using the principle of time of flight (Time of Flight, TOF) can measure the distance of the target to obtain the distance information containing the target. In ToF technology, the technology of directly measuring the time of flight of light is called dToF (direct-TOF); and The measurement technology that periodically modulates the emitted optical signal, measures the phase delay of the reflected optical signal relative to the emitted optical signal, and then calculates the time of flight from the phase delay is called iToF (Indirect-TOF) technology.

For the distance measurement system TOF, the calculation formula of the distance is:

Among them, c is the speed of light, about 3×10 ⁸ m/s, and k is a positive integer, representing the number of integer periods. If only one modulation frequency is used for distance measurement, it is impossible to confirm which distance period the real distance falls, that is, the k value cannot be confirmed. This phenomenon is called the distance ambiguity phenomenon of TOF ranging. Usually, the default k=0 in a measurement . When the modulation frequency is f, the distance value corresponding to an integer number of cycles is called the fuzzy distance of the distance value corresponding to 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 object under test, 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 measured twice continuously 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 existing in the prior art, an embodiment of the present application provides an ITOF ranging system and a method for shielding fuzzy distance values.

In order to achieve the above-mentioned purpose, the technical scheme of the embodiment of the present application is realized in this way:

In the first aspect, the embodiment of the present application provides an ITOF ranging system, including: a transmitter, a collector, and a processing circuit;

The transmitter is configured to emit a signal beam of a first frequency toward the object to be measured; wherein the first frequency is lower than the maximum frequency corresponding to the system preset ranging maximum value;

The collector is configured to collect part of the signal light beam reflected back by the object to be measured and output a charge signal;

The processing circuit is connected with the transmitter and the collector, calculates the target distance value of the object to be measured according to the charge signal, and determines that the target distance value is fuzzy according to the charge signal and the first threshold When the distance value is set, the fuzzy distance value is masked.

In some embodiments, the first threshold is the maximum value of the system preset distance measurement, and the processing circuit obtains the system preset maximum value of distance measurement; if it is determined that the target distance value is greater than, or greater than or If it is equal to the system preset maximum distance measurement value, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is shielded.

In some embodiments, the first threshold is a resolution threshold, and the processing circuit acquires ambient light data and sampling signal data according to the amount of charge corresponding to the light signal reflected back by the object to be measured, and according to the ambient light data Calculate the target resolution of the object to be measured with the sampled signal data; if it is determined that the target resolution is less than, or less than or equal to, the resolution threshold, then determine that the target distance value is a fuzzy 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 sampling signal data; C _n is the ambient light data; a, b, c, d, e are all parameters; f is the lens focal length of the collector; Resolution is the target resolution.

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

In some embodiments, the processing circuit calculates the mean value of the ambient light intensity according to the sampled signal data and the ambient light data; 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 acquires sampling signal data and ambient light data corresponding to different initial sampling points, and calculates the sampling resolution of each of the initial sampling points; if the sampling resolution of any of the initial sampling points rate 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 sampling signal data and The ambient light data calculates the average value of the ambient light intensity.

In some embodiments, the processing circuit calculates the reflectance corresponding to each target sampling point according to the sampling signal data of each target sampling point and a pre-stored reflectance calculation rule; The ambient light data, the corresponding reflectance, and the calculation rule of the ambient light irradiance stored in advance, 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, R _e is the reflectivity of the measured object at any target sampling point; C _s is the sampling signal data of the target sampling point; N is the number of exposures required by the tap in the integration time of single-frame measurement; θ is the illumination Angle of incidence; 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 _s is the sampling signal data of the target sampling point; C _n is the ambient light data 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.

In some embodiments, the first threshold is a preset sampling signal data threshold, and the processing circuit obtains the sampling signal data according to the amount of charge corresponding to the light signal reflected by the object to be measured. If the sampling signal is determined to be If the data is less than, or less than or equal to, the sampling signal data threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

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

Obtain the charge signal corresponding to the signal beam reflected by the object to be measured; transmit the signal beam of the first frequency towards the object to be measured through the transmitter, and be received by the collector after reflection to output the charge signal; wherein, the first frequency is less than The maximum frequency of the transmitted optical signal corresponding to the system preset ranging maximum value;

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

When it is determined according to the target distance value and the first threshold that the target distance value is a fuzzy distance value, the fuzzy distance value is masked.

In some embodiments, the first threshold is the maximum value preset by the system, and when the target distance value is determined to be an ambiguous distance value according to the target distance value and the first threshold value, the Fuzzy distance values, including:

Obtain the maximum value of the system preset distance measurement; if it is determined that the target distance value is greater than, or greater than or equal to the system preset distance measurement maximum value, then determine that the target distance value is a fuzzy distance value, and block the Blur distance value.

In some embodiments, the first threshold is a resolution threshold, and when the target distance value is determined to be a fuzzy distance value according to the target distance value and the first threshold value, masking the fuzzy distance value includes:

Obtain ambient light data and sampled signal data according to the amount of charge corresponding to the light signal reflected back by the object to be measured, and calculate the target resolution of the object to be measured according to the sampled signal data and the ambient light data; If the target resolution is greater than, or greater than or equal to, the resolution threshold, then it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

In some embodiments, the first threshold is a preset sampling signal data threshold, and when it is determined according to the target distance value and the first threshold that the target distance value is a fuzzy distance value, the fuzzy distance is masked. values, including:

Calculate the sampling signal data according to the charge corresponding to the light signal reflected back by the object to be measured, and if it is determined that the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, then determine that the target distance value is ambiguous Distance value, mask the fuzzy distance value.

In a third aspect, an embodiment of the present application provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a method for shielding a fuzzy distance value is implemented, so The method for shielding the fuzzy distance value includes steps:

Obtain the charge signal corresponding to the signal beam reflected by the object to be measured; transmit the signal beam of the first frequency towards the object to be measured through the transmitter, and be received by the collector after reflection to output the charge signal; wherein, the first frequency is less than The maximum frequency of the transmitted optical signal corresponding to the system preset ranging maximum value;

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

When it is determined according to the target distance value and the first threshold that the target distance value is a fuzzy distance value, the fuzzy distance value is masked.

Compared with the prior art, the ITOF ranging system of the present application 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; Determine whether the target distance value is a fuzzy distance value, and mask the fuzzy distance value. The invention solves the problem of shielding the fuzzy ranging value of the ranging system based on the preset threshold, realizes single-frequency ranging, improves the measurement frame rate, and solves the problem of blurring the ranging while increasing the system frame rate.

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 an ITOF ranging system shown in an exemplary embodiment of the present application;

FIG. 2 is a schematic flowchart of a method for masking fuzzy distance values shown in an exemplary embodiment of the present application;

FIG. 3 is a schematic structural diagram of a device for masking fuzzy distance values shown in an exemplary embodiment of the present application;

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

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.

Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a ranging system according to an exemplary embodiment of the present application. The ranging system 10 includes a transmitter 11 , a collector 12 and a processing circuit 13 . Wherein, the transmitter 11 emits a light beam 50 to the target space to illuminate the object 20 in the space, at least part of the emitted light beam 50 is reflected by the object 20 to form a reflected light beam 50 ′, and at least part of the reflected light beam 50 ′ is collected by the collector 12; the processing circuit 13 Connect with the transmitter 11 and the collector 12 respectively, synchronize the trigger signals of the transmitter 11 and the collector 12 to calculate the time required for the light beam to be sent by the transmitter 11 and received by the collector 12, that is, the emitted beam 50 and the reflected beam 50' The flight time t between, further, the distance D of the corresponding point on the object can be calculated by the following formula:

Among them, c is the speed of light; t is the flight time between the emitted beam and the reflected beam.

The transmitter 11 includes a light source and a light source driver (not shown in FIG. 1 ) and the like. Wherein, the light source can be a light emitting diode (LED), edge emitting laser (EEL), vertical cavity surface emitting laser (VCSEL) and other light sources, or a light source array composed of multiple light sources, and the light beam emitted by the light source can be visible light, infrared light, ultraviolet light, etc.

The collector 12 includes an image sensor 121, a lens unit, a filter (not shown in FIG. 1) and the like. The lens unit receives at least part of the light beams reflected back by the object and guides the at least part of the light beams to the image sensor 121, and the filter is a narrow-band filter matching the wavelength of the light source, used to suppress background light noise or stray light. The image sensor can be an image sensor array composed of a charge-coupled device (CCD), a complementary metal-oxide semiconductor (CMOS), etc., and the size of the array represents the resolution of the distance measurement system, such as 320×240. In an embodiment of the present invention, the image sensor 121 includes at least one pixel, and each pixel includes a plurality of taps, which are used to store and read or discharge charge signals generated by incident photons under the control of corresponding electrodes, according to The amount of charge accumulated by the tap during the integration time calculates the ambient light data and adopts the signal data. For example, each pixel includes 2 taps, and the taps are sequentially switched in a certain order within a single frame period (or a single exposure time) to collect the corresponding optical signal, to receive the optical signal and convert it into an electrical signal, and to read the charge signal data. For another example, each pixel includes three taps, and the taps are sequentially switched in a certain order within a single frame period to collect corresponding light signals, and one of the taps is used to collect ambient light signals.

The processing circuit 13 may be an independent dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc. composed of a CPU, memory, bus, etc., or may include a general-purpose processing circuit.

In some embodiments, the processing circuit 13 is used to provide the modulation signal (emission signal) required when the light source emits laser light, and the light source emits a pulsed beam to the object under the control of the modulation signal; in addition, the processing circuit 13 also provides an image sensor 121 The demodulation signal (acquisition signal) of the taps in each pixel. Under the control of the demodulation signal, the taps collect the charge signal generated by the pulse beam reflected by the object to be tested, and calculate the phase difference based on the charge signal to obtain the object 20 distance. For example, in the case of 2 taps, the expression for calculating the distance of the object is as follows:

Among them, c is the speed of light; T is the exposure period; Q1 and Q2 are the accumulated charges of the two taps respectively.

In the embodiment of the present invention, the transmitter is configured to emit a signal beam of a first frequency toward the object to be measured, wherein the first frequency is lower than the maximum frequency corresponding to the maximum value of the preset range of the ranging system; the collector is configured to collect the signal beam to be measured Measure the part of the signal beam reflected by the object and output the charge signal; the processing circuit is connected with the transmitter and the collector, calculate the target distance value of the object to be measured according to the charge signal, and determine the target distance according to the target distance value and the preset threshold Whether the value is a fuzzy distance value, and mask the fuzzy distance value.

Specifically, the processing circuit obtains the maximum ranging value corresponding to the preset maximum frequency of the emitted light signal, and uses the maximum ranging value as the preset distance threshold; if the target distance value is greater than the preset distance threshold, then it is determined that the target distance value is Fuzzy distance value, mask the fuzzy distance value.

Specifically, assuming that the maximum measurement range of the system is D, the period is usually set as time T, and T=2D/c, then the frequency of the emitted optical signal is

Assuming that the frequency of the transmitted optical signal is set to f=15Mhz during system design, the corresponding period is 66.66ns, and the maximum ranging range is 10m. In the embodiment of the present invention, in order to solve the distance aliasing, the frequency of the modulated transmitted optical signal is f ₁ , f ₁ <f, for example, f ₁ =8Mhz, the corresponding period is 125ns, which extends the actual ranging range of the system to 18.75m. Correspondingly, the single-frequency sampling time of the collector is also extended to the corresponding 125ns.

In an optional embodiment, the processing circuit judges whether the object to be measured is within the distance measuring range through a preset quantitative resolution threshold. Specifically, the processing circuit obtains the environmental Light data and sampling signal data, calculate the target resolution of the object to be measured according to the ambient light data and sampling signal data; if the target resolution is greater than the preset quantitative resolution threshold, then determine that the target distance value is a fuzzy distance value, and shield the fuzzy distance value.

In the embodiment of the present invention, ambient light data and sampling signal data are obtained according to the charge signal accumulated by the taps of the pixels within the integration time. Assuming that each pixel includes 3 taps, the reflected light signal is collected within the integration time and the output charge A _1-3 is output, and two of the taps are used to collect the reflected light signal, then the charge A ₁ collected by these two taps is , A ₂ represent the collected sampling signal data, and the other tap is used to collect the ambient light signal, and this tap is used to output the collected charge amount A ₃ to represent the ambient light data.

In an optional embodiment, when each pixel includes a plurality of taps, the sinusoidal waveform of the reflected signal collected by the collector can also be fitted according to the output charges of the plurality of taps, for example, the fitted sinusoidal curve is: y=a+b*cost+c*sint, the amplitude and the DC amount can be determined according to the fitted curve, wherein the amplitude is used to represent the sampling signal data, and the DC amount is used to represent the ambient light data. In an optional embodiment, the amplitude of the sine wave fitting curve is

DC flow is

Then, the sampled signal data is expressed as

The ambient light data is expressed as

The processing circuit calculates the target resolution according to the ambient light data, the sampled signal data and the preset resolution calculation rule. The system pre-stores preset resolution calculation rules, that is, the corresponding relationship between ambient light data, sampling signal data, and resolution, and the processing circuit calculates the target resolution according to the pre-stored resolution calculation rules.

It should be noted that there is no specific limitation on the preset resolution calculation rule in this embodiment. 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 A rule can be modeled as a function as follows:

Among them, C _s is the sampling signal data; C _n is the ambient light data; a, b, c, d are 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 sampling signal data; C _n is the ambient light data; a, b, c, d, e are parameters; f represents the lens focal length 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 processing circuit 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 shielded. .

It should be noted that 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 limited. greatly reduced. To overcome ranging ambiguity without sacrificing too much ranging range.

In an optional embodiment, it may be determined whether the object to be measured is within the distance measurement range by determining a variable resolution threshold, wherein the variable resolution threshold is determined according to an average value of ambient light. The processing circuit obtains the sampled signal data and the ambient light data, calculates the target resolution of the object to be measured according to the sampled signal data and the ambient light data; calculates the average value of the ambient light intensity according to the sampled signal data and the ambient light data; according to the calculated average value of the ambient light intensity, and The fitting function relationship between the preset variable resolution threshold and the average value of the ambient light intensity determines the variable resolution threshold; 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 , mask the fuzzy distance value.

Specifically, the processing circuit calculates the target resolution of the object to be measured according to the sampled signal data and the ambient light data for specific details, which can be referred to the detailed description above, and will not be repeated here.

The processing circuit first obtains the sampling signal data and ambient light data corresponding to different initial sampling points, and calculates the sampling resolution of each initial sampling point according to the sampling signal data and ambient light data; if the sampling resolution is less than the preset sampling resolution threshold, or, 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 sampled signal data and ambient light data of each target sampling point; finally, determine the variable resolution threshold value according to the fitting function relationship between the preset mean value of ambient light intensity and the variable resolution threshold value.

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 value of ambient light intensity based on the sampling signal data and ambient light data of target sampling points, first calculate the reflectance corresponding to each target sampling point according to the sampling signal data of each target sampling point and the pre-stored reflectance calculation rules; then, according to According to the ambient light data of 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 sampled signal data and the reflectivity, and the reflectivity of the object under test is calculated according to the corresponding relationship between the sampled signal data and the reflectivity.

Wherein, the corresponding relationship between the sampled signal data and the reflectivity can be derived according to the relational expression between the sampled signal data and the reflectivity. In addition to being affected by the reflectivity of the measured object, the sampled signal data collected by the collector is also affected by factors such as the number of tap exposures, 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, calibration of other When the factors are fixed, the corresponding relationship between the sampling signal data and the reflectivity is to derive the calculation rule of the reflectivity. When using the ITOF ranging system for ranging, the device can obtain information such as the number of tap exposures, the incident angle of light, the measurement distance of the measured object, the peak power of the signal beam emitted by the light source, and calculate the measured value according to the pre-stored reflectance calculation rules. The reflectivity of the measured object.

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

Among them, R _e is the reflectivity of the measured object at any target sampling point; C _s is the sampling signal data of the target sampling point; N is the number of exposures required by the tap in the integration time of single-frame measurement; θ is the illumination Incidence angle; 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, which is a constant determined according to the design of the system. For different system designs, the constant k ₁ will change.

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 sampled signal data and the reflectance is not limited to the above relational expression, and the above relational expression does not specifically limit the correspondence between the sampled signal data and the reflectance.

In some embodiments, the ambient light irradiance is calculated according to ambient light data, reflectance, and calculation rules for ambient light irradiance pre-stored in the device.

Specifically, the device can calculate the ambient light irradiance according to the ambient light data, sampled signal data, lens focal length of the collector, light incident angle, reflectivity, and calculation rules for ambient light irradiance pre-stored in the device.

As a non-limiting example, 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 _s is the sampling signal data of the target sampling point; C _n is the ambient light data 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 collector lens; k ₂ is the second preset coefficient, k ₃ is the third preset coefficient, the second preset coefficient and the third preset coefficient are determined according to the design of the system constant, which will vary with different system designs.

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 sampled ambient light intensity corresponding to each target sampling point is first calculated according to the sampled ambient light irradiance corresponding to each target sampling point, and then the sampled ambient light intensity corresponding to each target sampling point is averaged 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 of n target sampling points satisfying the preset quantitative resolution threshold constraint, and obtain the average ambient illuminance 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 illuminance. The simulation simulates the resolution threshold of shielding distance fuzzy under different ambient lighting conditions, and obtains the linear function relationship between the resolution threshold and the ambient light irradiance: Resolution=aE+b. After obtaining E, the preset variable resolution can be obtained rate threshold.

In an optional embodiment, in order to avoid sacrificing the ranging range, a sampling signal data threshold may be used to mask ranging ambiguity. Specifically, the sampling signal data threshold is set in advance, and the processor acquires real-time sampling signal data. If the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance is shielded. value.

Please refer to Fig. 2, Fig. 2 is a schematic flow chart of the method for shielding the fuzzy distance value of the ITOF ranging system shown in an exemplary embodiment of the present invention, and the method includes the following steps:

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

In the embodiment of the present invention, the signal beam of the first frequency is emitted toward the object to be measured 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 charge signal is output. Wherein, the first frequency is lower than the maximum frequency of the transmitted optical signal corresponding to the preset ranging maximum value of the ranging system.

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

In the embodiment of the present invention, the processing circuit provides the modulation signal required when the transmitter emits the signal beam, and the transmitter transmits the signal beam to the object under the control of the modulation signal; in addition, the processing circuit also provides the taps in each pixel of the image sensor. The demodulation signal, under the control of the demodulation signal, the tap collects the reflected light signal including the reflected light signal from the object under test and outputs the charge signal, and the processing circuit calculates the phase difference based on the charge signal to obtain the target distance value of the object under test.

S203: If it is determined according to the charge signal and the first threshold that the target distance value is a fuzzy distance value, mask the fuzzy distance value;

In some embodiments, the first threshold is the system preset ranging maximum value. The processing circuit obtains the maximum value of the system preset distance measurement; if it is determined that the target distance value is greater than, or greater than or equal to the system preset distance measurement maximum value, then it is determined that the target distance value is a fuzzy distance value, and the The blur distance value.

In some embodiments, the first threshold is a resolution threshold. The processing circuit acquires ambient light data and sampling signal data according to the charge corresponding to the light signal reflected back by the object to be measured, and calculates the target resolution of the object to be measured according to the sampling signal data and the ambient light data; if If it is determined that the target resolution is greater than, or greater than or equal to, the resolution threshold, then it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

Wherein, the resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold.

In some embodiments, the first threshold is a preset sampling signal data threshold, and the processing circuit calculates the sampling signal data according to the charge amount corresponding to the light signal reflected back by the object to be measured, and if it is determined that the sampling signal data is less than , or if it is less than or equal to the sampled signal data threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

It should be noted that, in some embodiments, the method for shielding the fuzzy distance value in the embodiment of the present invention can be implemented by using the ITOF ranging system in any of the foregoing embodiments. For specific details, please refer to the distance measuring system embodiment. description and will not be repeated here.

Please refer to FIG. 3 . FIG. 3 is a schematic structural diagram of an apparatus for masking fuzzy distance values 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. 1 and FIG. 2 . For ease of description, only the parts related to this embodiment are shown. Referring to Fig. 3, the device 3 for shielding the fuzzy distance value of the ITOF ranging system includes:

An acquisition unit 310, configured to acquire a charge 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 charge 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 charge signal and the first threshold. Further, the first threshold is a preset quantitative resolution threshold. The processing unit 330 is specifically used for:

Obtain sampled signal data and ambient light data;

calculating the target resolution of the object to be measured according to the sampled signal data and the ambient light data;

If it is determined that the target resolution is greater than, or greater than or equal to, a preset quantitative resolution threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

Further, the first threshold is a variable resolution threshold. The processing unit 330 is specifically used for:

Obtain sampled signal data and ambient light data;

calculating the target resolution of the object to be measured according to the sampled signal data and the ambient light data;

If it is determined that the target resolution is greater than, or greater than or equal to, the variable resolution threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

Further, the first threshold is a preset sampling signal data threshold. The processing unit 330 is specifically used for:

Obtain sampled signal data;

If the sampled signal data is less than, or less than or equal to, the sampled signal data threshold, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

Further, the first threshold is a system preset ranging maximum value. The processing unit 330 is specifically used for:

Obtaining the maximum value of the system preset ranging;

If it is determined that the target distance value is greater than, or greater than or equal to, the system preset distance measurement maximum value, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.

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 accomplishing specific functions, and the instruction segments are used to describe the execution process of the computer program 42 in the device 4 for masking fuzzy distance values. 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 it is determined according to the charge signal and the first threshold that the target distance value is a fuzzy distance value.

The device 4 for masking 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 that shields the fuzzy distance value of the ITOF ranging system, and does not constitute a limitation to the device 4 that shields the fuzzy distance value, and may include more or less than the figure Components, or a combination of certain components, or different components, for example, the device 4 for shielding fuzzy distance values of the ITOF ranging 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 the fuzzy distance value, for example, a hard disk or a memory of the device 4 for shielding the fuzzy distance value of the ITOF ranging system. Described memory 41 also can be the external storage device of the equipment 4 of shielding fuzzy distance value, for example the plug-in type hard disk equipped on the equipment 4 of shielding fuzzy distance value, smart memory card (Smart Media Card, SMC), safe digital (Secure Digital (Secure Digital) 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 masking fuzzy distance values 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 realize 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 USB flash drive, 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 (16)

1. A kind of ITOF ranging system, is characterized in that, comprises: transmitter, collector, and processing circuit;

   The transmitter is configured to emit a signal beam of a first frequency toward the object to be measured; wherein the first frequency is lower than the maximum frequency corresponding to the system preset ranging maximum value;

   The collector is configured to collect part of the signal light beam reflected back by the object to be measured and output a charge signal;

   The processing circuit is connected with the transmitter and the collector, calculates the target distance value of the object to be measured according to the charge signal, and determines that the target distance value is fuzzy according to the charge signal and the first threshold When the distance value is set, the fuzzy distance value is masked.
2. The ITOF ranging system according to claim 1, wherein the first threshold is the system preset ranging maximum value, and the processing circuit obtains the system preset ranging maximum value; if it is determined that the If the target distance value is greater than, or greater than or equal to, the system preset distance measurement maximum value, then it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.
3. The ITOF ranging system according to claim 1, wherein the first threshold is a resolution threshold, and the processing circuit acquires ambient light data and Sampling signal data, calculating the target resolution of the object to be measured according to the ambient light data and the sampled signal data; if it is determined that the target resolution is greater than, or greater than or equal to, the resolution threshold, then determine the The target distance value is a fuzzy distance value, and the fuzzy distance value is shielded.
4. The ITOF ranging system according to claim 3, 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 sampling signal data; C _n is the ambient light data; a, b, c, d, e are all parameters; f is the lens focal length of the collector; Resolution is the target resolution.
5. The ITOF ranging system according to claim 3, wherein the resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold, and the variable resolution threshold is determined according to the average value of ambient light.
6. The ITOF distance measuring system according to claim 5, wherein the processing circuit calculates the ambient illuminance mean value according to the sampled signal data and the ambient light data; according to the ambient illuminance mean value and a preset fitting function The relationship determines the variable resolution threshold, and the preset fitting function relationship includes the relationship between the variable resolution threshold and the average value of ambient light intensity.
7. The ITOF ranging system according to claim 6, wherein the processing circuit obtains sampling signal data and ambient light data corresponding to different initial sampling points, and calculates the sampling resolution of each initial sampling point; if any The sampling resolution of the 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 each The sampled signal data and the ambient light data of the target sampling point are used to calculate the average value of the ambient light intensity.
8. The ITOF ranging system according to claim 7, wherein the processing circuit calculates the corresponding distance of each target sampling point according to the sampling signal data of each of the target sampling points and the pre-stored reflectance calculation rule. Reflectance; according to the ambient light data 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 sampling ambient illuminance corresponding to each target sampling point according to the sampling ambient light irradiance corresponding to each target sampling point, and calculate the mean value of ambient illuminance according to the sampling ambient illuminance corresponding to each target sampling point.
9. The ITOF ranging system according to claim 8, wherein the pre-stored reflectivity calculation rule is:

   

   Among them, R _e is the reflectivity of the measured object at any target sampling point; C _s is the sampling signal data of the target sampling point; N is the number of exposures required by the tap in the integration time of single-frame measurement; θ is the illumination Angle of incidence; 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 _s is the sampling signal data of the target sampling point; C _n is the ambient light data 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.
10. The ITOF ranging system according to claim 1, wherein the first threshold is a preset sampling signal data threshold, and the processing circuit obtains the corresponding charge amount according to the light signal reflected back by the object to be measured. For sampling signal data, if it is determined that the sampled signal data is less than, or less than or equal to, the threshold value of the sampled signal data, it is determined that the target distance value is a fuzzy distance value, and the fuzzy distance value is masked.
11. A method for shielding fuzzy distance values, comprising:

    Obtain the charge signal corresponding to the signal beam reflected by the object to be measured; transmit the signal beam of the first frequency towards the object to be measured through the transmitter, and be received by the collector after reflection to output the charge signal; wherein, the first frequency is less than The maximum frequency of the transmitted optical signal corresponding to the system preset ranging maximum value;

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

    When it is determined according to the target distance value and the first threshold that the target distance value is a fuzzy distance value, the fuzzy distance value is masked.
12. The method for shielding fuzzy distance values according to claim 11, wherein the first threshold is the system preset range maximum value, and the target is determined according to the target distance value and the first threshold When the distance value is a fuzzy distance value, the fuzzy distance value is masked, including:

    Obtain the maximum value of the system preset distance measurement; if it is determined that the target distance value is greater than, or greater than or equal to the system preset distance measurement maximum value, then determine that the target distance value is a fuzzy distance value, and block the Blur distance value.
13. The method for shielding fuzzy distance values according to claim 11, wherein the first threshold is a resolution threshold, and determining the target distance value according to the target distance value and the first threshold is a fuzzy distance value , then mask the fuzzy distance value, including:

    Obtain ambient light data and sampled signal data according to the amount of charge corresponding to the light signal reflected back by the object to be measured, and calculate the target resolution of the object to be measured according to the sampled signal data and the ambient light data; If the target resolution is less than, or less 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 masked.
14. The method for shielding fuzzy distance values according to claim 11, wherein the first threshold is a preset sampling signal data threshold, and the target distance value is determined according to the target distance value and the first threshold When it is a fuzzy distance value, the fuzzy distance value is masked, including:

    Calculate the sampling signal data according to the charge corresponding to the light signal reflected back by the object to be measured, and if it is determined that the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, then determine that the target distance value is ambiguous Distance value, masking the fuzzy distance value.
15. A computer-readable storage medium, the computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, a method for shielding a fuzzy distance value is implemented, and the shielded fuzzy distance value The method includes the steps of:

    Obtain the charge signal corresponding to the signal beam reflected by the object to be measured; transmit the signal beam of the first frequency towards the object to be measured through the transmitter, and be received by the collector after reflection to output the charge signal; wherein, the first frequency is less than The maximum frequency of the transmitted optical signal corresponding to the system preset ranging maximum value;

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

    When it is determined according to the target distance value and the first threshold that the target distance value is a fuzzy distance value, the fuzzy distance value is masked.
16. The computer-readable storage medium according to claim 15, wherein the first threshold is the system preset range maximum value, and the target distance is determined according to the target distance value and the first threshold When the value is a fuzzy distance value, the fuzzy distance value is masked, including:

    Obtain the maximum value of the system preset distance measurement; if it is determined that the target distance value is greater than, or greater than or equal to the system preset distance measurement maximum value, then determine that the target distance value is a fuzzy distance value, and block the Blur distance value.

Images