Single-photon multi-pulse detection method, system and functional circuit

Abstract

The single-photon multipulse detection method, system, and functional circuit provided in this invention are applied to a single-photon detection system, including: multiple D flip-flops, an XOR-AND unit, an adder, a comparator, and a processor; the output terminal of the Mth D flip-flop is connected to the input terminal of the (M+1)th D flip-flop, and is also connected to the Nth input port of the XOR-AND unit; the input terminal of the 1st D flip-flop is connected to the input terminal of the functional circuit; the Mth output port of the XOR-AND unit is connected to the Mth input port of the adder; the output port of the adder is connected to the input port of the comparator; and the output port of the comparator is connected to the processor. Through the functional circuit provided in this application, the first target signal can be output only when the single-photon detector emits a photon, thereby improving the conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, and in particular to a single-photon multipulse detection method, system, and functional circuit. Background Technology

[0002] In the field of 3D imaging technology, 3D imaging techniques based on single-photon detection, such as APD (Avalanche Photon Diode), SiPM (Silicon Photomultiplier), and SPAD (Single Photon Avalanche Diode), have become a research hotspot in recent years. Single-photon detection allows for the counting of individual photons, enabling the detection of extremely weak target signals.

[0003] However, although current single-photon detectors have high sensitivity, they are easily affected by sunlight. When the received signal contains only a small amount of effective signal and most of it is interference and noise, the conversion efficiency is often low during signal conversion. Summary of the Invention

[0004] The purpose of this invention is to provide a functional circuit and detection system to improve the conversion efficiency in single-photon detection. The specific technical solution is as follows:

[0005] A first aspect of this application provides a single-photon multipulse detection method applied to a single-photon detection system, the method comprising:

[0006] Receive a pulse signal to be processed, wherein the pulse signal to be processed is a multi-pulse signal;

[0007] The pulse signal to be processed is waveform encoded to obtain multiple target waveform encoding results; the multiple target waveform encoding results are compared with pre-configured transmission waveform encoding data to obtain a comparison result. When the level signal at the time corresponding to the target waveform encoding result and the pre-configured transmission waveform are both the first target signal, the comparison result is the output of the first target signal; otherwise, the comparison result is the second signal. The first target signal in the pre-configured transmission waveform encoding is used to indicate that a photon is actually emitted at the corresponding time.

[0008] The number of first target signals in the comparison results is counted to obtain statistical results;

[0009] The statistical result is compared with a preset threshold, and the comparison result is output. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which triggers the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data based on the first level signal. Otherwise, the comparison result is a second level signal, which is used to trigger the time-to-digital converter (TDC) not to output time data.

[0010] The first time data is processed, and a depth map is generated based on the processed histogram data.

[0011] Optionally, comparing the multiple target waveform encoding results with pre-configured transmitted waveform encoding data to obtain comparison results includes:

[0012] The multiple target waveform encoding results are logically calculated with the pre-configured transmitted waveform encoding data, and the calculation result is used as the comparison result.

[0013] Optionally, comparing the multiple target waveform encoding results with pre-configured transmitted waveform encoding data to obtain comparison results includes:

[0014] By using a preset formula:

[0015] C1 = Q m XNOR S m AND S m =~(Q) m ^S m )&S m

[0016] The multiple target waveform encoding results are logically calculated with the pre-configured transmitted waveform encoding data, and the calculation result is used as the comparison result. Here, ~, ^, &, represent bitwise NOT operation, bitwise XOR operation, and bitwise AND operation, respectively. Qm represents the signal output by the Mth D flip-flop among the multiple D flip-flops. Sm represents the received pre-configured waveform encoding. C1 represents the calculation result. XNOR represents the XNOR gate, and AND represents the AND gate.

[0017] Optionally, the step of counting the number of first target signals in the comparison results to obtain statistical results includes:

[0018] The first target signal is binary encoded;

[0019] The first target signal with binary encoding is summed to obtain the statistical result.

[0020] Optionally, summing the binary-encoded first target signal to obtain statistical results includes:

[0021] By using a preset formula:

[0022]

[0023] The first target signal encoded in binary is summed to obtain the statistical result, where C2 represents the summation result and C1 represents the statistical result. M This represents the binary code of the Mth first target signal.

[0024] Optionally, the first target signal and the first level signal are high-level signals, and the second signal and the second level signal are low-level signals.

[0025] A second aspect of this application provides a functional circuit applied to a single-photon detection system, comprising:

[0026] The system comprises multiple D flip-flops, an XOR-AND unit, an adder, a comparator, and a processor. The output of the Mth D flip-flop is connected to the input of the (M+1)th D flip-flop and to the Nth input port of the XOR-AND unit. The input of the 1st D flip-flop is connected to the input of the functional circuit. The Mth output port of the XOR-AND unit is connected to the Mth input port of the adder. The output port of the adder is connected to the input port of the comparator. The output port of the comparator is connected to the processor.

[0027] The plurality of D flip-flops are used to receive the pulse signal to be processed, wherein the pulse signal to be processed is a multi-pulse signal;

[0028] The XOR-AND unit is used to perform waveform encoding on the pulse signal to be processed to obtain multiple target waveform encoding results; and to compare the multiple target waveform encoding results with pre-configured transmission waveform encoding data to obtain a comparison result. When the level signal at the time corresponding to the target waveform encoding result and the pre-configured transmission waveform are both the first target signal, the comparison result is the output of the first target signal; otherwise, the comparison result is the second signal. The first target signal in the pre-configured transmission waveform encoding is used to indicate that a photon is actually emitted at the corresponding time.

[0029] The adder is used to count the number of first target signals in the comparison results to obtain statistical results;

[0030] The comparator is used to compare the statistical result with a preset threshold and output the comparison result. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which is used to trigger the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data. Otherwise, the comparison result is a second level signal, which is used to trigger the time-to-digital converter (TDC) not to output data.

[0031] The processor is used to process the first time data and generate a depth map based on the processed histogram data.

[0032] Optionally, the XOR-AND unit is specifically used to perform logical calculations on the multiple target waveform encoding results and pre-configured transmitted waveform encoding data, and use the calculation results as comparison results.

[0033] Optionally, the XOR-AND unit is specifically used to apply a preset formula:

[0034] C1 = Q m XNOR S m AND S m =~(Q) m ^S m )&S m

[0035] The multiple target waveform encoding results are logically calculated with the pre-configured transmitted waveform encoding data, where ~, ^, &, represent bitwise NOT, bitwise XOR, and bitwise AND operations, respectively. m Sm represents the signal output by the Mth D flip-flop among the plurality of D flip-flops; C1 represents the pre-configured waveform code received; XNOR represents the calculation result corresponding to the Mth D flip-flop among the plurality of D flip-flops; AND represents the AND gate.

[0036] Optionally, the adder is specifically used to perform binary encoding on the first target signal output from each output port of the XOR-AND unit; sum the binary encoding, and use the summation result as the statistical result.

[0037] Optionally, the adder is specifically used to perform a preset formula:

[0038]

[0039] The binary codes are summed, where C2 represents the summation result and C1 represents the summation result. M This represents the binary encoding of the first target signal output from the Mth output port of the XOR-AND unit.

[0040] Optionally, the driving terminals of the plurality of D flip-flops are all connected to a common clock.

[0041] Optionally, the first target signal and the first level signal are high-level signals, and the second signal and the second level signal are low-level signals.

[0042] In another aspect of the embodiments of this application, a detection system is provided, including any of the functional circuits described above.

[0043] Beneficial effects of the embodiments of the present invention:

[0044] This invention provides a functional circuit and detection system applied to a single-photon detection system, comprising: multiple D flip-flops, an XOR-AND unit, an adder, a comparator, and a processor; the output of the Mth D flip-flop is connected to the input of the (M+1)th D flip-flop, and to the Nth input port of the XOR-AND unit; the input of the 1st D flip-flop is connected to the input of the functional circuit; the Mth output port of the XOR-AND unit is connected to the Mth input port of the adder; the output port of the adder is connected to the input port of the comparator; the output port of the comparator is connected to the processor; the multiple D flip-flops are used to receive a pulse signal to be processed, wherein the pulse signal to be processed is a multi-pulse signal; the XOR-AND unit is used to perform waveform encoding on the pulse signal to be processed to obtain multiple target waveform encoding results; and compares the multiple target waveform encoding results with pre-configured transmitted waveform encoding data to obtain... The comparison results are as follows: when both the target waveform encoding result and the level signal corresponding to the pre-configured transmitted waveform at the corresponding time are first target signals, the comparison result is an output first target signal; otherwise, the comparison result is a second signal. The first target signal in the pre-configured transmitted waveform encoding indicates that a photon was actually emitted at the corresponding time. The adder is used to count the number of first target signals in the comparison result to obtain a statistical result. The comparator is used to compare the statistical result with a preset threshold and output a comparison result. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which triggers the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data. Otherwise, the comparison result is a second level signal, which triggers the time-to-digital converter (TDC) not to output data. The processor is used to process the first time data and generate a depth map based on the processed histogram data. The functional circuit provided in this application embodiment can compare the pulse signal with a pre-configured waveform code to ensure that the first target signal is output only when the single-photon detector emits a photon, and compare the number of the first target signals with a preset threshold. When the number of the first target signals is greater than the preset threshold, the first target signal is output, thereby reducing the influence of ambient light on the conversion result and improving the conversion efficiency.

[0045] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0047] Figure 1 A schematic diagram of the structure of a functional circuit provided in an embodiment of this application;

[0048] Figure 2 An example diagram of a functional circuit provided in an embodiment of this application;

[0049] Figure 3 A schematic diagram of the detection system provided in an embodiment of this application;

[0050] Figure 4 An example diagram of a detection system provided in an embodiment of this application;

[0051] Figure 5 This is a schematic flowchart of a single-photon multipulse detection method provided in an embodiment of this application. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of the present invention.

[0053] First, the technical terms that may be used in the embodiments of this application will be explained:

[0054] SPAD: Single Photon Avalanche Diode;

[0055] SiPM: Silicon Photomultiplier;

[0056] APD: Avalanche Photon Diode;

[0057] TDC: Time Digital Converter;

[0058] Histogram: In this patent, it specifically refers to the histogram accumulated from a certain amount of TDC data in a SPAD-based ranging scheme.

[0059] A first aspect of this application provides a functional circuit applied to a single-photon detection system, see [link to relevant documentation]. Figure 1 The system includes: multiple D flip-flops 101, an XOR-AND unit 102, an adder 103, a comparator 104, and a processor 105; the output of the Mth D flip-flop is connected to the input of the (M+1)th D flip-flop and to the Nth input port of the XOR-AND unit; the input of the 1st D flip-flop is connected to the input of the functional circuit; the Mth output port of the XOR-AND unit is connected to the Mth input port of the adder; the output port of the adder is connected to the input port of the comparator; and the output port of the comparator is connected to the processor.

[0060] D flip-flop 101 is used to receive the pulse signal to be processed, which is a multi-pulse signal.

[0061] The XOR-AND unit 102 is used to perform waveform encoding on the pulse signal to be processed to obtain multiple target waveform encoding results; and compare the multiple target waveform encoding results with the pre-configured transmission waveform encoding data to obtain a comparison result. When the level signal at the time corresponding to the target waveform encoding result and the pre-configured transmission waveform are both the first target signal, the comparison result is the output of the first target signal; otherwise, the comparison result is the second signal. The first target signal in the pre-configured transmission waveform encoding is used to indicate that a photon is actually emitted at the corresponding time.

[0062] Adder 103 is used to count the number of first target signals in the comparison results and obtain the statistical results;

[0063] Comparator 104 is used to compare the statistical result with a preset threshold and output the comparison result. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which is used to trigger the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data; otherwise, the comparison result is a second level signal, which is used to trigger the time-to-digital converter (TDC) not to output data.

[0064] Processor 105 is used to process the first-time data and generate a depth map based on the processed histogram data.

[0065] In one example, the pulse signal to be processed is a multi-pulse signal. In actual use, each pulse in this multi-pulse signal is processed through multiple D flip-flops, XOR-AND units, adders, and comparators to obtain a comparison result. Then, the pulse signal to be processed is interpreted using the first target signal or the second signal corresponding to each pulse to obtain the information carried by the pulse signal to be processed.

[0066] The aforementioned D flip-flops can be cascaded together, meaning the output of one D flip-flop serves as the input of the next. Optionally, see [link to relevant documentation]. Figure 2 The driving terminals of multiple D flip-flops are all connected to a common clock. These D flip-flops are information storage devices with two stable states and are the most basic logic units for constructing various sequential circuits. They can flip from one stable state to another. The D flip-flops flip at the leading edge of the clock pulse (positive transition 0→1), and the next state of the flip-flop depends on its state before the rising edge of the clock pulse arrives.

[0067] In one example, the pre-configured waveform encoding has both the MSB (Most Significant Bit) and LSB (Least Significant Bit) set to 1, and exhibits good autocorrelation. See also Figure 2 The AND-OR unit 102 is also used to receive pre-configured waveform codes.

[0068] In one example, the comparator is also used to receive the information output by the adder and threshold information; compare the information output by the adder with the threshold information, and output the comparison result. The comparator can compare the output result of the adder with the relevant threshold. When the output result of the adder is greater than the relevant threshold, the output is 1; when the output result of the adder is not greater than the relevant threshold, the output is 0. In this embodiment, the pulse signal to be processed is a multi-pulse signal, that is, the transmitted waveform contains multiple pulses, and the corresponding waveform code contains multiple 1s. Thus, the removal of ambient light interference is achieved by comparing with the relevant threshold.

[0069] As can be seen, the functional circuit of this application embodiment can compare the pulse signal with the pre-configured waveform code to achieve the output of the first target signal only when the single-photon detector emits a photon, and compare the number of the first target signals counted with a preset threshold. When the number of the first target signals is greater than the preset threshold, the first target signal is output, thereby reducing the influence of ambient light on the conversion result and improving the conversion efficiency.

[0070] Optional, XOR-AND unit, specifically used to perform logical calculations on multiple target waveform encoding results and pre-configured transmitted waveform encoding data, and use the calculation results as comparison results.

[0071] Optional, XOR-AND unit, specifically used for using preset formulas:

[0072] C1 = Q m XNOR S m AND S m =~(Q) m ^S m )&S m

[0073] The encoded results of multiple target waveforms are logically calculated together with the pre-configured transmitted waveform encoded data, where ~, ^, &, represent bitwise NOT, bitwise XOR, and bitwise AND operations, respectively. Q m Sm represents the signal output by the Mth D flip-flop among multiple D flip-flops; C1 represents the pre-configured waveform code received; XNOR represents the calculation result corresponding to the Mth D flip-flop among multiple D flip-flops; AND represents the AND gate.

[0074] In one example, an XNOR-AND unit can be composed of XNOR-AND logic. XNOR-AND logic can perform logical calculations on the output signals of each of multiple cascaded D flip-flops. For instance, the output signal of each flip-flop is compared with each bit of a pre-configured waveform code; if all bits in the same bit are 1, the logical calculation result is 1; otherwise, it is 0.

[0075] As can be seen, the functional circuit provided in this application embodiment can denoise the pulse signal, filter out interference signals and noise in the single-photon detection process, avoid subsequent processing such as conversion, storage, and operation of a large number of invalid signals, and reduce chip area and power consumption.

[0076] Optionally, an adder is used to encode the first target signal output from each output port of the XOR-AND unit into binary; sum the binary codes and use the summation result as a statistical result.

[0077] Optional, adder, specifically used to add via a preset formula:

[0078]

[0079] Summing the binary codes, where C2 represents the summation result, and C1 represents the summation result. M This represents the binary code of the first target signal output from the Mth output port of the XOR-AND unit.

[0080] The adder can probe the calculation results of the XOR-AND unit. Specifically, it can calculate the comparison result of each bit and sum each 1 in the calculation result to obtain the corresponding output result.

[0081] The functional circuit provided in this application embodiment can denoise the pulse signal, filter out interference signals and noise in the single-photon detection process, avoid subsequent processing such as conversion, storage, and operation of a large number of invalid signals, and reduce chip area and power consumption.

[0082] To illustrate the solutions of the embodiments of this application, the following description is provided in conjunction with specific examples. (See also...) Figure 2 ;

[0083] The relevant detection module contains M cascaded D flip-flops (D1, D2...D... M All D flip-flops are driven by a common clock with a frequency of F (MHz). The pulse signal is input from D1, passes through D2, D3... and finally exits from D... M Output.

[0084] The outputs of all D flip-flops are Q1...Q M , denoted as Q m The input is fed in parallel to unit C1. Unit C1 also receives pre-configured external waveform encoding input, denoted as S. m C1 internally consists of XNOR-AND logic, and its output is:

[0085] C1 = Q m XNOR S m AND S m =~(Q) m ^S m )&S m

[0086] In the formula, the operators ~^& represent bitwise NOT, bitwise XOR, and bitwise AND operations, respectively.

[0087] The purpose of this calculation is to compare each bit of the code Q with that of the code S: if both Q and S have a 1 in the same bit, the result is 1; otherwise, it is 0. The physical meaning of this calculation is: the waveform Q detected by the single-photon detector is compared with the transmitted waveform (i.e., the pre-configured waveform) S. If the single-photon detector detects '1' and a pulse is actually emitted at the corresponding moment, then it is considered that a transmitted signal has been detected, and therefore '1' is output; otherwise, 0 is output.

[0088] Since a single pulse is insufficient to effectively remove ambient light interference, this solution employs a multi-pulse approach, meaning the transmitted waveform contains multiple pulses, and the corresponding waveform encoding includes multiple '1's. For the function of module C1, please refer to [link / reference needed]. Figure 2 .

[0089] The output of C1 is directly input into the adder module C2. The function of C2 is simple: to count the number of '1's in the binary code output by C1. That is, to sum the bits of the binary code output by C1. Therefore, the expression for C2 is:

[0090]

[0091] The output of C2 represents the degree of matching between the transmitted pulse sequence and the received pulse. Assuming there are p pulses in the transmitted pulse sequence, then C2 ≤ p. Therefore, the relevant threshold q must also satisfy q ≤ p. The output of C2 is directly input to comparator C3. C3 compares C2 with q; if C2 >= q, it outputs '1', otherwise it outputs '0'. If it outputs '1', it triggers TDC to output a time value; otherwise, TDC will not output anything.

[0092] Clearly, a larger q results in stricter decision conditions and stronger suppression of ambient light, but may also lead to the loss of more valid signals. Conversely, a smaller q results in more lenient decision conditions and a lower probability of losing valid signals, but may also lead to weaker suppression of ambient light. Therefore, the selection of the correlation threshold q requires comprehensive consideration of both environmental and system factors.

[0093] Regarding waveform encoding: MSB and LSB must be 1, and good autocorrelation is required.

[0094] Regarding delay compensation: Since the relevant decision needs to wait for the pulse sequence to be fully received, the time of TDC output is delayed relative to the first pulse, but this delay can be compensated, and it is numerically equal to the length of the pulse sequence.

[0095] A second aspect of this application provides a detection system including the aforementioned functional circuits.

[0096] See Figure 3 It includes: a single-photon detector 301, a quenching circuit 302, a pulse shaping circuit 303, a TDC (Time to Digital Converter) 304, a histogram accumulation module 305, a histogram processing module 306, a depth information generation module 307, and any of the above functional circuits 308.

[0097] Optionally, a single-photon detection unit 301 is used to receive the optical signal to be processed and perform photoelectric conversion on the optical signal to be processed to generate photocurrent;

[0098] Quenching circuit 302 is used to process photocurrent and generate pulse signal to be shaped;

[0099] The pulse shaping circuit 303 is used to shape the pulse signal to be shaped into a pulse signal to be processed with a preset amplitude and width.

[0100] The TDC304 is used to convert the comparison results output by the functional circuit into digital signals.

[0101] Histogram accumulation module 305 is used to generate a data accumulation histogram based on the digital signal;

[0102] Histogram processing module 306 is used to filter digital signals based on data accumulation histograms to obtain filtered signals.

[0103] The depth information generation module 307 is used to perform peak filtering on the filtered signal and calculate the corresponding depth information based on the filtered peaks.

[0104] Optionally, the TDC304 is used to perform delay compensation on the comparison results and convert the delay-compensated comparison results into digital signals.

[0105] To illustrate the solutions of the embodiments of this application, the following description is provided in conjunction with specific examples. (See also...) Figure 4 The figure shows a single-photon detection receiving system, consisting of a single-photon detection unit, a quenching circuit, a pulse shaping circuit, a correlation detection module, a time-to-digital conversion unit, a histogram accumulation unit, a histogram processing unit, and a depth generation unit. The functions of each part are explained below:

[0106] Single-photon detection unit: receives optical signals and performs photoelectric conversion to generate photocurrent.

[0107] Quenching circuit: works in conjunction with the single-photon detection unit to generate pulse signals.

[0108] Pulse shaping circuit: Shapes the input raw pulse signal into a pulse signal with limited amplitude and width.

[0109] The relevant detection module is a key feature of this patent. This module enables relevant decision-making, suppresses noise interference, and improves detection performance.

[0110] TDC: Converts the time difference between the transmission and reception of an optical signal into a digital signal.

[0111] Histogram Accumulation Module: Uses TDC to accumulate data into a histogram (horizontal axis represents time value, and vertical axis represents the number of times that time value occurs).

[0112] Histogram processing module: performs de-stacking and other filtering processes on histograms.

[0113] Depth information generation module: By filtering peaks in the histogram, the horizontal coordinate (time value t) corresponding to the peaks is obtained, and the distance d (i.e., depth information) is calculated using d = c * t / 2, where c is the speed of light.

[0114] The system provided in this application embodiment can denoise pulse signals, filter out interference signals and noise in the single-photon detection process, avoid subsequent processing such as conversion, storage, and operation of a large number of invalid signals, and reduce chip area and power consumption.

[0115] A third aspect of this application provides a single-photon multipulse detection method applied to a single-photon detection system. The system includes: multiple D flip-flops, an XOR-AND unit, an adder, and a comparator. See [link to relevant documentation]. Figure 5 The above methods include:

[0116] Step S51: Receive the pulse signal to be processed, which is a multi-pulse signal;

[0117] Step S52: The pulse signal to be processed is waveform encoded to obtain multiple target waveform encoding results; and the multiple target waveform encoding results are compared with the pre-configured transmission waveform encoding data to obtain a comparison result. When the level signal at the time corresponding to the target waveform encoding result and the pre-configured transmission waveform are both the first target signal, the comparison result is the output of the first target signal; otherwise, the comparison result is the second signal. The first target signal in the pre-configured transmission waveform encoding is used to indicate that a photon is actually emitted at the corresponding time.

[0118] Step S53: Count the number of first target signals in the comparison results to obtain the statistical results;

[0119] Step S54: Compare the statistical result with a preset threshold and output the comparison result. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which triggers the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data based on the first level signal. Otherwise, the comparison result is a second level signal, which is used to trigger the time-to-digital converter (TDC) not to output time data.

[0120] Step S55: Process the first time data and generate a depth map based on the processed histogram data.

[0121] Optionally, the encoding results of multiple target waveforms are compared with pre-configured transmitted waveform encoding data to obtain comparison results, including:

[0122] The results of multiple target waveform encoding are logically calculated with the pre-configured transmitted waveform encoding data, and the calculation results are used as the comparison results.

[0123] Optionally, the encoding results of multiple target waveforms are compared with pre-configured transmitted waveform encoding data to obtain comparison results, including:

[0124] By using a preset formula:

[0125] C1 = Q m XNOR S m AND S m=~(Q) m ^S m )&S m

[0126] The results of multiple target waveform encoding are logically calculated with the pre-configured transmitted waveform encoding data, and the calculation result is used as the comparison result. Here, ~, ^, & represent bitwise NOT operation, bitwise XOR operation, and bitwise AND operation, respectively. Qm represents the signal output by the Mth D flip-flop among multiple D flip-flops. Sm represents the received pre-configured waveform encoding. C1 represents the calculation result. XNOR represents the XNOR gate, and AND represents the AND gate.

[0127] Optionally, the number of first target signals in the comparison results can be counted to obtain statistical results, including:

[0128] The first target signal is binary encoded;

[0129] The first target signal with binary encoding is summed to obtain the statistical results.

[0130] Optionally, the first target signal encoded in binary is summed to obtain statistical results, including:

[0131] By using a preset formula:

[0132]

[0133] The first target signal encoded in binary is summed to obtain a statistical result, where C2 represents the summation result and C1 represents the result of the summation. M This represents the binary code of the Mth first target signal.

[0134] Optionally, the first target signal and the first level signal are high-level signals, while the second signal and the second level signal are low-level signals.

[0135] The method provided in this application embodiment can denoise pulse signals, filter out interference signals and noise in the single-photon detection process, avoid subsequent processing such as conversion, storage, and operation of a large number of invalid signals, and reduce chip area and power consumption.

[0136] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0137] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0138] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0139] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A single-photon multipulse detection method, characterized in that, Applied to single-photon detection systems, the method includes: Receive a pulse signal to be processed, wherein the pulse signal to be processed is a multi-pulse signal; The pulse signal to be processed is waveform encoded to obtain multiple target waveform encoding results; the multiple target waveform encoding results are compared with pre-configured transmission waveform encoding data to obtain a comparison result. When the level signal at the time corresponding to the target waveform encoding result and the pre-configured transmission waveform are both the first target signal, the comparison result is the output of the first target signal; otherwise, the comparison result is the second signal. The first target signal in the pre-configured transmission waveform encoding is used to indicate that a photon is actually emitted at the corresponding time. The number of first target signals in the comparison results is counted to obtain statistical results; The statistical result is compared with a preset threshold, and the comparison result is output. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which triggers the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data according to the first level signal. Otherwise, the comparison result is a second level signal, which is used to trigger the time-to-digital converter (TDC) not to output time data. The first time data is processed, and a depth map is generated based on the processed histogram data.

2. The method according to claim 1, characterized in that, The step of comparing the encoding results of the plurality of target waveforms with the pre-configured transmitted waveform encoding data to obtain the comparison results includes: The multiple target waveform encoding results are logically calculated with the pre-configured transmitted waveform encoding data, and the calculation result is used as the comparison result.

3. The method according to claim 2, characterized in that, The step of comparing the encoding results of the plurality of target waveforms with the pre-configured transmitted waveform encoding data to obtain the comparison results includes: By using a preset formula: ； The multiple target waveform encoding results are logically calculated with the pre-configured transmitted waveform encoding data, and the calculation result is used as the comparison result, where ~, ^, &, represent bitwise NOT, bitwise XOR, and bitwise AND operations, respectively, and Q... m S represents the signal output by the Mth D flip-flop in a plurality of D flip-flops; m C1 represents the pre-configured waveform code, C1 represents the calculation result, XNOR represents the XNOR gate, and AND represents the AND gate.

4. The method according to claim 3, characterized in that, The statistical results obtained by counting the number of first target signals in the comparison results include: The first target signal is binary encoded; The first target signal with binary encoding is summed to obtain the statistical result.

5. The method according to claim 4, characterized in that, The summation of the binary-encoded first target signal to obtain statistical results includes: By using a preset formula: ， The first target signal encoded in binary is summed to obtain the statistical result, where C2 represents the summation result and C1 represents the statistical result. M This represents the binary code of the Mth first target signal.

6. The method according to claim 1, characterized in that, The first target signal and the first level signal are high-level signals, and the second signal and the second level signal are low-level signals.

7. A functional circuit, characterized in that, Applications in single-photon detection systems include: The system comprises multiple D flip-flops, an XOR-AND unit, an adder, a comparator, and a processor. The output of the Mth D flip-flop is connected to the input of the (M+1)th D flip-flop and to the Nth input port of the XOR-AND unit. The input of the 1st D flip-flop is connected to the input of the functional circuit. The Mth output port of the XOR-AND unit is connected to the Mth input port of the adder. The output port of the adder is connected to the input port of the comparator. The output port of the comparator is connected to the processor. The plurality of D flip-flops are used to receive the pulse signal to be processed, wherein the pulse signal to be processed is a multi-pulse signal; The XOR-AND unit is used to perform waveform encoding on the pulse signal to be processed to obtain multiple target waveform encoding results; and to compare the multiple target waveform encoding results with pre-configured transmission waveform encoding data to obtain a comparison result. When the level signal at the time corresponding to the target waveform encoding result and the pre-configured transmission waveform are both the first target signal, the comparison result is the output of the first target signal; otherwise, the comparison result is the second signal. The first target signal in the pre-configured transmission waveform encoding is used to indicate that a photon is actually emitted at the corresponding time. The adder is used to count the number of first target signals in the comparison results to obtain statistical results; The comparator is used to compare the statistical result with a preset threshold and output the comparison result. When the statistical result is greater than the preset threshold, the comparison result is a first level signal, which is used to trigger the time-to-digital converter (TDC) to convert the pulse signal to be processed into first time data. Otherwise, the comparison result is a second level signal, which is used to trigger the time-to-digital converter (TDC) not to output data. The processor is used to process the first time data and generate a depth map based on the processed histogram data.

8. The circuit according to claim 7, characterized in that, The XOR-AND unit is specifically used to perform logical calculations on the multiple target waveform encoding results and the pre-configured transmitted waveform encoding data, and use the calculation results as comparison results.

9. The circuit according to claim 8, characterized in that, The XOR-AND unit is specifically used to apply a preset formula: ； The multiple target waveform encoding results are logically calculated with the pre-configured transmitted waveform encoding data, where ~, ^, &, represent bitwise NOT, bitwise XOR, and bitwise AND operations, respectively. m S represents the signal output by the Mth D flip-flop among the plurality of D flip-flops; m C1 represents the pre-configured waveform code, C1 represents the calculation result corresponding to the Mth D flip-flop among the plurality of D flip-flops, XNOR represents the XNOR gate, and AND represents the AND gate.

10. The circuit according to claim 7, characterized in that, The adder is specifically used to perform binary encoding on the first target signal output from each output port of the XOR-AND unit; sum the binary encoding, and use the summation result as the statistical result.

11. The circuit according to claim 10, characterized in that, The adder is specifically used to perform a preset formula: ， The binary codes are summed, where C2 represents the summation result and C1 represents the summation result. M This represents the binary encoding of the first target signal output from the Mth output port of the XOR-AND unit.

12. The circuit according to claim 7, characterized in that, The driving terminals of the multiple D flip-flops are all connected to a common clock.

13. The circuit according to claim 7, characterized in that, The first target signal and the first level signal are high-level signals, and the second signal and the second level signal are low-level signals.

14. A single-photon multipulse detection system, characterized in that, include: The functional circuit as described in any one of claims 7-13.

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