ITOF distance measurement system and method for shielding fuzzy distance value

Abstract

The present invention provides an ITOF ranging system and a method for shielding ambiguous distance values, comprising: a transmitter, a collector, and a processing circuit; the transmitter is configured to emit a signal beam of a first frequency toward an object to be measured; the first frequency is less than a maximum frequency corresponding to a preset maximum range value of the system; the collector is configured to collect a portion of the signal beam reflected back by the object to be measured and output a charge signal; the processing circuit is connected to the transmitter and the collector, and determines, based on the charge signal and a first threshold, that the target distance value is an ambiguous distance value, and then shields the ambiguous distance value. Based on the first threshold, the present invention solves the problem of shielding ambiguous distance values ​​in a ranging system, implements single-frequency ranging, and improves the measurement frame rate.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to an ITOF distance measurement system and a method for shielding fuzzy distance values. Background Art

[0002] The time of flight (TOF) principle can be used to measure the distance to a target to obtain distance information including the target. In ToF technology, the technology that directly measures the flight time of light is called dToF (direct-TOF); and the measurement technology that periodically modulates the transmitted light signal, measures the phase delay of the reflected light signal relative to the transmitted light signal, and then calculates the flight time from the phase delay is called iToF (indirect-TOF) technology.

[0003] For the distance measurement system TOF, the distance calculation formula is: Where c is the speed of light, which is approximately 3×10 8 m / s, where k is a positive integer representing the number of cycles. If only a single modulation frequency is used for distance measurement, it's impossible to determine in which cycle the true distance falls, and therefore, the k value cannot be determined. This phenomenon is called distance ambiguity in TOF ranging. Typically, k = 0 is the default for a measurement. When the modulation frequency is f, the distance value corresponding to an integer number of cycles is called the ambiguous distance corresponding to the current modulation frequency.

[0004] Existing methods for resolving TOF distance ambiguity primarily involve dual-frequency ranging to address distance aliasing. Dual-frequency ranging involves measuring the same object using two different frequencies, and determining the true distance from these two measurements. However, this method requires two consecutive measurements of the distance to each target point using two different frequencies, significantly reducing the measurement frame rate. Traditional TOF ranging methods, which use a single frequency to measure distance, also suffer from distance ambiguity. Therefore, resolving distance ambiguity without sacrificing system frame rate is an urgent issue. Summary of the Invention

[0005] To overcome the problems existing in the prior art, embodiments of the present invention provide an ITOF distance measurement system and a method for shielding fuzzy distance values.

[0006] To achieve the above-mentioned purpose, the technical solution of the embodiment of the present invention is implemented as follows:

[0007] In a first aspect, an embodiment of the present invention provides an ITOF ranging system, comprising: a transmitter, a collector, and a processing circuit;

[0008] The transmitter is configured to transmit a signal light beam of a first frequency toward the object to be measured; wherein the first frequency is less than a maximum frequency corresponding to a preset maximum distance measurement value of the system;

[0009] The collector is configured to collect a portion of the signal light beam reflected by the object to be measured and output a charge signal;

[0010] The processing circuit is connected to the transmitter and the collector, calculates the target distance value of the object to be measured according to the charge signal, and shields the fuzzy distance value when the target distance value is determined to be a fuzzy distance value according to the charge signal and a first threshold.

[0011] In some embodiments, 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 target distance value is greater than, or greater than or equal to, the system preset ranging maximum value, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

[0012] In some embodiments, the first threshold is a resolution threshold, and the processing circuit obtains ambient light data and sampling signal data based on the amount of 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 based on the ambient light data and the sampling signal data; if it is determined that the target resolution is less than, or less than or equal to the resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0013] 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:

[0014] The first function model is:

[0015] The second function model is:

[0016] 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 represents the focal length of the collector lens; Resolution is the target resolution.

[0017] 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 illumination.

[0018] In some embodiments, the processing circuit calculates the mean ambient light illuminance based on the sampled signal data and the ambient light data; determines the variable resolution threshold based on the mean ambient light illuminance and a preset fitting function relationship, and the preset fitting function relationship includes the relationship between the variable resolution threshold and the mean ambient light illuminance.

[0019] In some embodiments, the processing circuit obtains 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 is less than a preset sampling resolution threshold, or the sampling resolution is less than or equal to the preset sampling resolution threshold, the initial sampling point is marked as a target sampling point; and the average ambient light illumination is calculated based on the sampling signal data and ambient light data of each of the target sampling points.

[0020] In some embodiments, the processing circuit calculates the reflectivity corresponding to each target sampling point based on the sampling signal data of each target sampling point and a pre-stored reflectivity calculation rule; calculates the sampled ambient light irradiance corresponding to each target sampling point based on the ambient light data of each target sampling point, the corresponding reflectivity, and a pre-stored ambient light irradiance calculation rule; calculates the sampled ambient light illuminance corresponding to each target sampling point based on the sampled ambient light irradiance corresponding to each target sampling point, and calculates the average ambient light illuminance based on the sampled ambient light illuminance corresponding to each target sampling point.

[0021] In some embodiments, the pre-stored reflectivity calculation rule is:

[0022]

[0023] Among them, R e is the reflectivity of the object under test 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 within the integration time of a single frame measurement; θ is the incident angle of light; L is the measurement distance of the object being measured; P t is the peak power of the signal beam emitted by the light source; k1 is the first preset coefficient;

[0024] In some embodiments, the pre-stored calculation rule for ambient light irradiance is:

[0025]

[0026] Among them, I AL is the ambient light irradiance at any target sampling point; C s is the sampling signal data of the target sampling point; C nis the ambient light data of the target sampling point; θ is the incident angle of light; L is the measurement distance of the object under test; f represents the focal length of the collector lens; k2 is the second preset coefficient, and k3 is the third preset coefficient.

[0027] In some embodiments, the first threshold is a preset sampling signal data threshold, and the processing circuit obtains sampling signal data based on the charge amount corresponding to the light signal reflected back by the object to be measured. If it is determined that the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0028] In a second aspect, an embodiment of the present invention provides a method for shielding a fuzzy distance value, comprising:

[0029] Acquire a charge signal corresponding to a signal light beam reflected by the object to be measured; transmit a signal light beam of a first frequency toward the object to be measured by a transmitter, which is received by a collector after reflection to output the charge signal; wherein the first frequency is less than the maximum frequency of the transmitted light signal corresponding to the maximum distance measurement value preset by the system;

[0030] Calculating a target distance value of the object to be measured according to the charge signal;

[0031] 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 shielded.

[0032] In some embodiments, the first threshold is a maximum distance measurement value preset by the system, and when determining, based on the target distance value and the first threshold, that the target distance value is a fuzzy distance value, shielding the fuzzy distance value includes:

[0033] Obtain the system preset maximum distance measurement value; if it is determined that the target distance value is greater than, or greater than or equal to the system preset maximum distance measurement value, determine that the target distance value is a fuzzy distance value, and mask the fuzzy distance value.

[0034] In some embodiments, the first threshold is a resolution threshold, and when determining, based on the target distance value and the first threshold, that the target distance value is a fuzzy distance value, shielding the fuzzy distance value includes:

[0035] Ambient light data and sampling signal data are obtained based on the amount of charge corresponding to the light signal reflected back by the object to be measured, and the target resolution of the object to be measured is calculated based on the sampling 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 resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0036] In some embodiments, the first threshold is a preset sampling signal data threshold, and when the target distance value is determined to be a fuzzy distance value based on the target distance value and the first threshold, shielding the fuzzy distance value includes:

[0037] The sampling signal data is calculated based on the charge amount corresponding to the light signal reflected back by the object to be measured. If it is determined that the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0038] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for shielding the fuzzy distance value as described in any embodiment of the second aspect is implemented.

[0039] Compared to existing technologies, the ITOF ranging system 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 based on the electrical signal; determines whether the target distance value is a fuzzy distance value based on the target distance value and a preset threshold, and then shields the fuzzy distance value. Based on the preset threshold, the present invention solves the problem of shielding the ranging system from fuzzy ranging values, realizes single-frequency ranging, and improves the measurement frame rate, thus simultaneously solving the problem of fuzzy ranging and improving the system frame rate.

[0040] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

[0041] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of an ITOF ranging system according to an exemplary embodiment of the present invention;

[0043] Figure 2 A schematic flow chart of a method for shielding fuzzy distance values ​​according to an exemplary embodiment of the present invention;

[0044] Figure 3 A schematic structural diagram of a device for shielding fuzzy distance values ​​according to an exemplary embodiment of the present invention;

[0045] Figure 4 2 is a schematic diagram of a device for shielding fuzzy distance values ​​provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0046] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0047] The terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The singular forms "a," "the," and "the" used in this invention and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0048] See also Figure 1 , Figure 1 The schematic diagram of a distance measurement system according to an exemplary embodiment of the present invention is shown. The distance measurement system 10 includes a transmitter 11, a collector 12, and a processing circuit 13. The transmitter 11 transmits a light beam 50 to a target space to illuminate an object 20 in the space. At least a portion of the transmitted light beam 50 is reflected by the object 20 to form a reflected light beam 50', which is at least partially collected by the collector 12. The processing circuit 13 is connected to the transmitter 11 and the collector 12, respectively, and synchronizes the trigger signals of the transmitter 11 and the collector 12 to calculate the time required for the light beam to be emitted by the transmitter 11 and received by the collector 12, that is, the flight time t between the transmitted light beam 50 and the reflected light beam 50'. Furthermore, the distance D of the corresponding points on the object can be calculated by the following formula:

[0049]

[0050] Where c is the speed of light and t is the flight time between the emitted and reflected beams.

[0051] The transmitter 11 includes a light source and a light source driver ( Figure 1 The light source may be a light emitting diode (LED), an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), or a light source array composed of multiple light sources. The light beam emitted by the light source may be visible light, infrared light, ultraviolet light, or the like.

[0052] The collector 12 includes an image sensor 121, a lens unit, a filter ( Figure 1(not shown in the figure). The lens unit receives at least part of the light beam reflected by the object and guides the at least part of the light beam to the image sensor 121. The filter is a narrow-band filter that matches the wavelength of the light source and is used to suppress background light noise or stray light in the remaining bands. The image sensor can be an image sensor array composed of a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS), etc. 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 for storing and reading or discharging the charge signal generated by the incident photon under the control of the corresponding electrode, and calculating the ambient light data and the signal data based on the amount of charge accumulated by the tap during the integration time. For example, each pixel includes two taps, and the taps are switched in a certain order in a single frame period (or a single exposure time) to collect the corresponding light signal, receive the light signal and convert it into an electrical signal, and read the charge signal data. For another example, each pixel includes three taps, and the taps are switched in sequence in a certain order within a single frame period to collect corresponding light signals, and one of the taps is used to collect an ambient light signal.

[0053] 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 processing circuit.

[0054] In some embodiments, the processing circuit 13 is used to provide the modulation signal (transmission signal) required for the light source to emit laser light. Under the control of the modulation signal, the light source transmits a pulsed light beam toward the object under test. In addition, the processing circuit 13 also provides a demodulation signal (acquisition signal) of the taps in each pixel of the image sensor 121. Under the control of the demodulation signal, the taps collect the charge signal generated by the pulsed light beam reflected back from the object under test and calculate the phase difference based on the charge signal to obtain the distance of the object 20. For example, in the case of two taps, the expression for calculating the distance of the object is as follows:

[0055]

[0056] Where c is the speed of light; T is the exposure period; Q1 and Q2 are the charges accumulated in the two taps respectively.

[0057] In an embodiment of the present invention, a transmitter is configured to transmit a signal light beam of a first frequency toward an object to be measured, wherein the first frequency is less than a maximum frequency corresponding to a preset maximum distance measurement value of a ranging system; a collector is configured to collect a portion of the signal light beam reflected back by the object to be measured and output a charge signal; a processing circuit is connected to the transmitter and the collector, calculates a target distance value of the object to be measured based on the charge signal, determines whether the target distance value is a fuzzy distance value based on the target distance value and a preset threshold, and masks the fuzzy distance value.

[0058] Specifically, the processing circuit obtains the ranging maximum value corresponding to the preset maximum frequency of the emitted light signal, and uses the ranging maximum value as the preset distance threshold; if the target distance value is greater than the preset distance threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0059] Specifically, assuming that the maximum measurement range of the system is D, the period is usually set to time T, T = 2D / c, then the frequency of the emitted light signal is Assume that the system is designed with a transmitted optical signal frequency of f = 15 MHz, corresponding to a period of 66.66 ns, and a maximum ranging range of 10 meters. In this embodiment of the present invention, to address range aliasing, the transmitted optical signal is modulated to a frequency f1, where f1 < f. For example, f1 = 8 MHz, corresponding to a period of 125 ns, extending the system's actual ranging range to 18.75 meters. Correspondingly, the collector's single-frequency sampling time is also extended to 125 ns.

[0060] In an optional embodiment, the processing circuit determines whether the object to be measured is within the ranging range by using a preset quantitative resolution threshold. Specifically, the processing circuit obtains ambient light data and sampling signal data based on the amount of 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 based on the ambient light data and the sampling signal data; if the target resolution is greater than the preset quantitative resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0061] In the embodiment of the present invention, the ambient light data and the sampled signal data are obtained based on the charge signal accumulated by the tap of the pixel during the integration time. Assume that each pixel includes 3 taps, collects the reflected light signal during the integration time and outputs the charge amount A 1-3 Two of the taps are used to collect reflected light signals, and the charge amounts A1 and A2 collected by these two taps are used to represent the collected sampling signal data. The other tap is used to collect ambient light signals, and the charge amount A3 collected by the tap output is used to represent the ambient light data.

[0062] In an optional embodiment, when each pixel includes multiple taps, the sinusoidal waveform of the reflected signal collected by the collector can be fitted based on the output charge of the multiple taps. For example, the fitted sinusoidal curve is: y = a + b * cost + c * sint. The amplitude and DC value can be determined based on the fitted curve, where the amplitude is used to represent the sampled signal data and the DC value is used to represent the ambient light data. In an optional embodiment, the amplitude of the sine wave fitting curve is The DC flow is Then, the sampled signal data is expressed as Ambient light data is represented as

[0063] The processing circuit calculates the target resolution based on the ambient light data, the sampled signal data, and a preset resolution calculation rule. The system pre-stores the preset resolution calculation rule, i.e., the correspondence between the ambient light data, the sampled signal data, and the resolution. The processing circuit calculates the target resolution based on the pre-stored resolution calculation rule.

[0064] It should be noted that, in this embodiment, 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 the following function model:

[0065]

[0066] 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.

[0067] For another example, the preset resolution calculation rule may also be the following function model:

[0068]

[0069] 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 represents the focal length of the collector lens.

[0070] In order to accurately obtain the calculation result of the resolution, the sampling data can be fitted or trained to obtain a function model of the preset resolution calculation rule.

[0071] The processing circuit determines 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.

[0072] It should be noted that although the method of presetting quantitative resolution shielding solves the ranging ambiguity, it sacrifices a large ranging range, especially in long-range, high ambient light, and low reflectivity conditions, where the ranging range is greatly reduced. In order to overcome the ranging ambiguity without sacrificing too much ranging range, a new method is proposed.

[0073] In an optional embodiment, whether the object to be measured is within the range can be determined by determining a variable resolution threshold, wherein the variable resolution threshold is determined based on the mean ambient light illumination value. A processing circuit obtains sampled signal data and ambient light data, calculates a target resolution of the object to be measured based on the sampled signal data and the ambient light data, calculates the mean ambient light illumination value based on the sampled signal data and the ambient light data, determines the variable resolution threshold based on the calculated mean ambient light illumination value and a fitted function relationship between a preset variable resolution threshold and the mean ambient light illumination value, and determines that the target distance value is a fuzzy distance value if the target resolution is greater than, or greater than or equal to, the preset variable resolution threshold, and masks the fuzzy distance value.

[0074] Specifically, the specific details of how the processing circuit calculates the target resolution of the object to be measured based on the sampled signal data and the ambient light data can be referred to the detailed description above and will not be repeated here.

[0075] The processing circuit first obtains the sampled signal data and ambient light data corresponding to different initial sampling points, and calculates the sampling resolution of each initial sampling point based on the sampled signal data and the ambient light data. If the sampling resolution is less than a preset sampling resolution threshold, or less than or equal to the preset sampling resolution threshold, the initial sampling point is marked as a target sampling point. In other words, initial sampling points with a sampling resolution greater than, or greater than or equal to the preset sampling resolution threshold are masked out, and the remaining initial sampling points are marked as target sampling points.

[0076] Then, the mean ambient light illumination value is calculated based on the sampling signal data and ambient light data of each target sampling point; finally, the variable resolution threshold is determined based on the fitting function relationship between the preset ambient light illumination value and the variable resolution threshold.

[0077] 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 method for setting the preset quantitative resolution threshold above, which will not be repeated here. The target sampling point is the sampling point that meets the preset quantitative resolution threshold constraint.

[0078] When calculating the mean ambient light illuminance based on the sampling signal data and ambient light data of the target sampling points, first calculate the reflectance corresponding to each target sampling point based on the sampling signal data of each target sampling point and a pre-stored reflectance calculation rule; then, calculate the sampled ambient light irradiance corresponding to each target sampling point based on the ambient light data of each target sampling point, the corresponding reflectance, and the pre-stored ambient light irradiance calculation rule; finally, calculate the sampled ambient light irradiance corresponding to each target sampling point based on the sampled ambient light irradiance corresponding to each target sampling point, and calculate the mean ambient light illuminance based on the sampled ambient light irradiance corresponding to each target sampling point.

[0079] In some embodiments, a reflectivity calculation rule is pre-stored in the system, that is, a correspondence between sampled signal data and reflectivity, and the reflectivity of the object under test is calculated based on the correspondence between the sampled signal data and reflectivity.

[0080] Among them, the correspondence between the sampling signal data and the reflectivity can be derived based on the relationship between the sampling signal data and the reflectivity. In addition to being affected by the reflectivity of the object being measured, the sampling signal data collected by the collector will also be affected by factors such as the number of tap exposures, the incident angle of light, the measurement distance of the object being measured, and the peak power of the signal beam emitted by the light source. Therefore, when other factors are fixed, the correspondence between the sampling signal data and the reflectivity is calibrated 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 object being measured, the peak power of the signal beam emitted by the light source, and calculate the reflectivity of the object being measured based on the pre-stored reflectivity calculation rule.

[0081] In an optional embodiment, the pre-stored reflectivity calculation rule may be:

[0082]

[0083] Among them, R e is the reflectivity of the object under test 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 within the integration time of a single frame measurement; θ is the incident angle of light; L is the measurement distance of the object being measured; P t is the peak power of the signal beam emitted by the light source; k1 is the first preset coefficient, which is a constant determined according to the design of the system. For different system designs, the constant k1 will change.

[0084] According to the above-mentioned pre-stored reflectivity calculation rules, the reflectivity corresponding to each target sampling point can be calculated respectively. It can be understood that the correspondence between the sampled signal data and the reflectivity is not limited to the above-mentioned relationship, and the above-mentioned relationship does not specifically limit the correspondence between the sampled signal data and the reflectivity.

[0085] In some embodiments, the ambient light irradiance is calculated based on the ambient light data and the reflectivity and a calculation rule of the ambient light irradiance pre-stored in the device.

[0086] Specifically, the device can calculate the ambient light irradiance based on the ambient light data, the sampled signal data, the focal length of the collector lens, the light incident angle, the reflectivity, and the calculation rules of the ambient light irradiance pre-stored in the device.

[0087] As a non-limiting example, the pre-stored calculation rule for ambient light irradiance is:

[0088]

[0089] Among them, I AL is the ambient light irradiance at 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; L is the measurement distance of the object to be measured; f represents the focal length of the collector lens; k2 is the second preset coefficient, k3 is the third preset coefficient, the second preset coefficient and the third preset coefficient are constants determined according to the design of the system, and this constant will change for different system designs.

[0090] Based on the above-mentioned pre-stored ambient light irradiance calculation rules, the sampled 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-mentioned relationship, and the above-mentioned relationship does not specifically limit the pre-stored ambient light irradiance calculation rules.

[0091] In some embodiments, the sampling ambient light illuminance corresponding to each target sampling point is first calculated based on the sampling ambient light irradiance corresponding to each target sampling point, and then the sampling ambient light illuminance corresponding to each target sampling point is averaged to obtain the ambient light illuminance mean.

[0092] In an optional embodiment, the sampling ambient light irradiance of each target sampling point is first calculated based on the calculated sampling ambient light irradiance, and the following formula can be used for specific calculation:

[0093]

[0094] Among them, E i is the sampling ambient illumination of the target sampling point i, IAL is the sampled ambient light irradiance at 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.

[0095] Then, the sampled ambient light illuminance of multiple n target sampling points that meet the preset quantitative resolution threshold constraint is averaged to obtain the ambient light illuminance mean E:

[0096]

[0097] It should be noted that, in this embodiment, the target sampling points are numbered sequentially. It should be understood that sequential numbering may not be used in other embodiments.

[0098] In some embodiments, the fitting function relationship between the variable resolution threshold and the mean ambient light illumination value may be specifically set in the following manner.

[0099] The linear function relationship between the resolution threshold and the mean ambient light irradiance is constructed as: Resolution = aE + b. The resolution threshold that blocks distance blur under different ambient lighting conditions is obtained to obtain calibration data for multiple sets of ambient light irradiance mean and resolution threshold values. The coefficients a and b are determined based on this calibration data. In actual distance measurement, the real-time variable resolution threshold, Resolution, can be determined based on the calculated ambient light mean E. Simulations are performed to simulate the resolution threshold that blocks distance blur under different ambient lighting conditions, and a linear function relationship between the resolution threshold and ambient light irradiance is obtained: Resolution = aE + b. After obtaining E, the preset variable resolution threshold can be obtained.

[0100] In an optional embodiment, to avoid sacrificing the ranging range, a sampling signal data threshold can be used to mask ranging ambiguity. Specifically, a sampling signal data threshold is pre-set, and the processor obtains real-time sampling signal data. If the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, the target distance value is determined to be an ambiguous distance value and the ambiguous distance value is masked.

[0101] See also Figure 2 , Figure 2 A flow chart of a method for shielding fuzzy distance values ​​in an ITOF ranging system according to an exemplary embodiment of the present invention is shown. The method comprises the following steps:

[0102] S201: Acquire a charge signal corresponding to a signal light beam reflected by the object to be measured;

[0103] In one embodiment of the present invention, a transmitter transmits a signal light beam of a first frequency toward an object to be measured. The reflected light signal is reflected by the object and received by a collector, which then outputs a charge signal. The first frequency is less than the maximum frequency of the transmitted light signal corresponding to a preset maximum range value of the ranging system.

[0104] S202: Calculating a target distance value of the object to be measured according to the charge signal;

[0105] In an embodiment of the present invention, the processing circuit provides the modulation signal required for the transmitter to emit a signal light beam. The transmitter emits the signal light beam toward the object to be measured under the control of the modulation signal. In addition, the processing circuit also provides a demodulation signal for the tap in each pixel of the image sensor. Under the control of the demodulation signal, the tap collects the reflected light signal reflected back by the object to be measured and outputs a charge signal. The processing circuit calculates the phase difference based on the charge signal to obtain the target distance value of the object to be measured.

[0106] S203: If it is determined according to the charge signal and the first threshold that the target distance value is a fuzzy distance value, masking the fuzzy distance value;

[0107] In some embodiments, the first threshold is a system-preset maximum distance measurement value. The processing circuit obtains the system-preset maximum distance measurement value; if it is determined that the target distance value is greater than, or greater than or equal to, the system-preset maximum distance measurement value, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

[0108] In some embodiments, the first threshold is a resolution threshold. The processing circuit obtains ambient light data and sampled signal data based on the amount of charge corresponding to the light signal reflected by the object to be measured, and calculates the target resolution of the object to be measured based on 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 resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

[0109] The resolution threshold includes a preset quantitative resolution threshold or a variable resolution threshold.

[0110] In some embodiments, the first threshold is a preset sampling signal data threshold, and the processing circuit calculates the sampling signal data based on the charge amount corresponding to the light signal reflected back by the object to be measured. If it is determined that the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0111] 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 using the ITOF ranging system of any of the aforementioned embodiments. For specific details, please refer to the description in the ranging system embodiment, which will not be repeated here.

[0112] See Figure 3 , Figure 3 The schematic diagram of the structure of the device for shielding the fuzzy distance value is shown as an exemplary embodiment of the present invention. The units included are used to perform Figure 2 For details of the steps in the corresponding embodiment, please refer to Figure 1 、 Figure 2 For the convenience of explanation, only the parts related to this embodiment are shown. Figure 3 , the device 3 for shielding fuzzy distance values ​​of the ITOF ranging system includes:

[0113] An acquisition unit 310 is configured to acquire a charge signal corresponding to a signal beam reflected by the object to be measured;

[0114] A calculation unit 320 is configured to calculate a target distance value of the object to be measured based on the charge signal;

[0115] 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 based on the charge signal and the first threshold. Furthermore, the first threshold is a preset quantitative resolution threshold. The processing unit 330 is specifically configured to:

[0116] Obtain sampled signal data and ambient light data;

[0117] Calculating the target resolution of the object to be measured according to the sampled signal data and the ambient light data;

[0118] If it is determined that the target resolution is greater than, or greater than or equal to, a preset quantitative resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0119] Furthermore, the first threshold is a variable resolution threshold. The processing unit 330 is specifically configured to:

[0120] Obtain sampled signal data and ambient light data;

[0121] Calculating the target resolution of the object to be measured according to the sampled signal data and the ambient light data;

[0122] If it is determined that the target resolution is greater than, or greater than or equal to, the variable resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

[0123] Furthermore, the first threshold is a preset threshold of the sampling signal data. The processing unit 330 is specifically configured to:

[0124] Get sampled signal data;

[0125] If the sampling signal data is less than, or less than or equal to, the sampling signal data threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is masked.

[0126] Furthermore, the first threshold is a system preset maximum distance measurement value. The processing unit 330 is specifically configured to:

[0127] Obtaining the system preset ranging maximum value;

[0128] If it is determined that the target distance value is greater than, or greater than or equal to, the system preset maximum distance measurement value, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

[0129] See Figure 4 , Figure 4 FIG. 1 is a schematic diagram of a device for shielding fuzzy distance values ​​provided by an exemplary embodiment of the present invention. Figure 4 As shown, the device 4 for shielding fuzzy distance values ​​in this embodiment includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40, such as a fuzzy distance value shielding program. When the processor 40 executes the computer program 42, the steps in the above-mentioned embodiments of the method for shielding fuzzy distance values ​​are implemented, such as Figure 2 Alternatively, when the processor 40 executes the computer program 42, the functions of the modules / units in the above-mentioned device embodiments are realized, for example, Figure 3 Functions of the units 310 to 330 are shown.

[0130] Exemplarily, the computer program 42 can be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 42 in the device 4 for masking the fuzzy distance value. 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:

[0131] An acquisition module, used to acquire an electrical signal corresponding to a signal light beam reflected by the object to be measured;

[0132] a calculation module, configured to calculate a target distance value of the object to be measured according to the electrical signal;

[0133] The processing module is configured to mask the fuzzy distance value if it is determined that the target distance value is a fuzzy distance value according to the charge signal and a first threshold.

[0134] The device 4 for shielding the fuzzy distance value may include, but is not limited to, a processor 40 and a memory 41. It will be understood by those skilled in the art that Figure 4 It is only an example of the device 4 for shielding fuzzy distance values ​​in the ITOF ranging system and does not constitute a limitation on the device 4 for shielding fuzzy distance values. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the device 4 for shielding fuzzy distance values ​​in the ITOF ranging system may also include input and output devices, network access devices, buses, etc.

[0135] The processor 40 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0136] The memory 41 can be an internal storage unit of the device 4 for shielding the fuzzy distance value, such as a hard disk or memory of the device 4 for shielding the fuzzy distance value of the ITOF ranging system. The memory 41 can also be an external storage device of the device 4 for shielding the fuzzy distance value, such as a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the device 4 for shielding the fuzzy distance value. Furthermore, the memory 41 can also include both an internal storage unit of the device 4 for shielding the fuzzy distance value 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 shielding the fuzzy distance value. The memory 41 can also be used to temporarily store data that has been output or is to be output.

[0137] 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 as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or 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 scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0138] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0139] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0140] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. 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 can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0141] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0142] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0143] If the integrated module / unit is implemented in the form of a software functional 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 implements all or part of the process in the above-mentioned embodiment method, and can also be completed by a computer program to instruct the relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of each of the above-mentioned method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals. The present invention is not limited to the above-mentioned embodiments. If various changes or modifications of the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims of the present invention and equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. An ITOF ranging system, characterized in that: include: Transmitter, collector, and processing circuit; The transmitter is configured to transmit a signal light beam of a first frequency toward the object to be measured; wherein the first frequency is less than a maximum frequency corresponding to a preset maximum distance measurement value of the system; The collector is configured to collect a portion of the signal light beam reflected by the object to be measured and output a charge signal; The processing circuit is connected to the transmitter and the collector, calculates the target distance value of the object to be measured according to the charge signal, and shields the fuzzy distance value when the target distance value is determined to be a fuzzy distance value according to the charge signal and a first threshold; The first threshold is a resolution threshold, and the processing circuit obtains ambient light data and sampling signal data based on the amount of 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 based on the ambient light data and the sampling signal data; if it is determined that the target resolution is greater than, or greater than or equal to the resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

2. The ITOF ranging system according to claim 1, 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 All are parameters; Indicates the focal length of the collector's lens; Resolution is the target resolution.

3. The ITOF ranging system according to claim 1, 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 the ambient light illumination.

4. The ITOF ranging system according to claim 3, wherein: The processing circuit calculates the mean ambient light illuminance based on the sampled signal data and the ambient light data; determines the variable resolution threshold based on the mean ambient light illuminance and a preset fitting function relationship, wherein the preset fitting function relationship includes the relationship between the variable resolution threshold and the mean ambient light illuminance.

5. The ITOF ranging system according to claim 4, wherein: The processing circuit obtains sampling signal data and ambient light data corresponding to different initial sampling points, and calculates a sampling resolution of each of the initial sampling points; if the sampling resolution of any of the initial sampling points is less than a preset sampling resolution threshold, or the sampling resolution is less than or equal to the preset sampling resolution threshold, marking the initial sampling point as a target sampling point; The ambient light illumination mean is calculated based on the sampling signal data and the ambient light data of each target sampling point.

6. The ITOF ranging system according to claim 5, characterized in that: The processing circuit calculates the reflectivity corresponding to each target sampling point based on the sampling signal data of each target sampling point and a pre-stored reflectivity calculation rule; calculates the sampled ambient light irradiance corresponding to each target sampling point based on the ambient light data of each target sampling point, the corresponding reflectivity, and a pre-stored ambient light irradiance calculation rule; calculates the sampled ambient light illuminance corresponding to each target sampling point based on the sampled ambient light irradiance corresponding to each target sampling point, and calculates the ambient light illuminance average based on the sampled ambient light illuminance corresponding to each target sampling point.

7. The ITOF ranging system according to claim 6, wherein: The pre-stored reflectivity calculation rule is: ， in, R e is the reflectivity of the object under test at any target sampling point; C s The sampling signal data of the target sampling point; N is the number of exposures required for the tap within the integration time of a single frame measurement; is the incident angle of light; L is the measuring distance of the object to be measured; 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: ， in, is the ambient light irradiance at any target sampling point; C s is the sampling signal data of the target sampling point; C n The ambient light data of the target sampling point; is the incident angle of light; L is the measuring distance of the object to be measured; Indicates the focal length of the collector's lens; k 2 is the second preset coefficient, k 3 is the third preset coefficient.

8. A method for shielding fuzzy distance values, characterized in that: include: Acquire a charge signal corresponding to a signal light beam reflected by the object to be measured; transmit a signal light beam of a first frequency toward the object to be measured by a transmitter, which is received by a collector after reflection to output the charge signal; wherein the first frequency is less than the maximum frequency of the transmitted light signal corresponding to the maximum distance measurement value preset by the system; 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, shielding the fuzzy distance value; 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, the fuzzy distance value is shielded, including: Ambient light data and sampling signal data are obtained based on the amount of charge corresponding to the light signal reflected back by the object to be measured, and the target resolution of the object to be measured is calculated based on the sampling signal data and the ambient light data; if it is determined that the target resolution is less than, or less than or equal to, the resolution threshold, the target distance value is determined to be a fuzzy distance value, and the fuzzy distance value is shielded.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for masking blur distance values ​​according to claim 8 is implemented.

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