CN118112539A

CN118112539A - Ranging method, ranging system and ranging device

Info

Publication number: CN118112539A
Application number: CN202211527114.2A
Authority: CN
Inventors: 张玺; 张睿; 宋林胤
Original assignee: Wuhan Arctic Core Microelectronics Co ltd
Current assignee: Wuhan Arctic Core Microelectronics Co ltd
Priority date: 2022-11-30
Filing date: 2022-11-30
Publication date: 2024-05-31

Abstract

A ranging method, a ranging system and a ranging device. The ranging method comprises the following steps: detecting a plurality of received optical signals and forming a plurality of single photon time code sequences, respectively, including detecting a plurality of optical pulses in each received optical signal and forming a single photon time code sequence, wherein each received optical signal includes an ambient optical signal and a signal optical pulse reflected by a target object; counting the plurality of single photon time code sequences to form a histogram; and carrying out peak searching operation on the histogram to determine the distance of the target object. The ranging method can effectively resist ambient light interference and improve ranging accuracy.

Description

Ranging method, ranging system and ranging device

Technical Field

The embodiment of the disclosure relates to a ranging method, a ranging system and a ranging device.

Background

The distance measurement can be performed on the target by utilizing the Time of Flight (ToF) correlation principle so as to obtain a depth image containing the depth value of the target, and the functions of three-dimensional reconstruction, face recognition, human-computer interaction and the like can be further realized based on the depth image. Related distance measurement systems have been widely used in the fields of consumer electronics, unmanned aerial vehicle, AR/VR, etc. Distance measuring systems based on the time-of-flight principle often comprise a beam emitter and a collector, wherein a light source in the emitter emits a beam to a target space, the beam reflected by the target is received by the collector, and the distance of the target object is calculated according to the time of flight of the light.

In practical application, because the sensitivity of the photodetector in the acquisition unit is higher, when the ambient light is stronger, the peak value of the target light signal is covered due to the accumulation effect of the ambient light, and the accurate distance cannot be measured.

Disclosure of Invention

At least one embodiment of the present disclosure provides a ranging method, including: detecting a plurality of received optical signals and forming a plurality of single photon time code sequences, respectively, comprising: detecting a plurality of light pulses in each received light signal and forming a single photon time code sequence, wherein each received light signal comprises an ambient light signal and a signal light pulse reflected by a target object; counting the plurality of single photon time code sequences to form a histogram; and carrying out peak searching operation on the histogram to determine the distance of the target object.

In some examples, detecting each received optical signal and forming a single photon time code sequence includes: a plurality of detection signal pulses are generated by a single photon avalanche photodiode in response to a plurality of light pulses in the received light signal and detected by a plurality of time-to-digital converters, respectively, to form the single photon time code sequence.

In some examples, detecting each received optical signal and forming a single photon time code sequence includes: a plurality of detection signal pulses are generated by a single photon avalanche photodiode in response to a plurality of light pulses in the received light signal and detected by a time to digital converter to form the single photon time code sequence.

In some examples, detecting each received optical signal and forming a single photon time code sequence includes: generating a plurality of paths of detection signals by a plurality of single photon avalanche photodiodes in response to the received light signals, and carrying out logic operation on the plurality of paths of detection signals to obtain optimized detection signals; the optimized detection signal is detected to form the single photon time code sequence.

In some examples, the logical operations include an and operation, an or operation, or a combination of an and or operation.

At least one embodiment of the present disclosure also provides a ranging system including a collector for detecting a plurality of light pulses in each received light signal and forming a single photon time code sequence to detect the plurality of received light signals to form a plurality of single photon time code sequences, wherein each received light signal includes an ambient light signal and a signal light pulse reflected by a target object, and a processing circuit. The processing circuit is connected with the collector and is used for counting a plurality of single photon time code sequences corresponding to a plurality of received light signals to form a histogram and carrying out peak searching operation on the histogram to determine the distance of the target object.

In some examples, the collector includes a plurality of collection units configured to detect a plurality of received light signals and form a plurality of single photon time code sequences, respectively; each acquisition unit comprises a detector and a recorder; the detector is used for detecting a plurality of light pulses in the corresponding received light signals to generate a plurality of detection signal pulses; the recorder is used for detecting the plurality of detection signal pulses to form the single photon time code sequence and outputting the single photon time code sequence to the processing circuit.

In some examples, each detector includes a single photon avalanche photodiode for generating a plurality of detection signal pulses in response to a plurality of light pulses.

In some examples, each recorder includes a time-to-digital converter and a pulse distribution circuit for distributing the plurality of detection signal pulses to the plurality of time-to-digital converters, respectively; each time-to-digital converter is configured to detect a corresponding detection signal pulse to form the single photon time code sequence.

In some examples, each recorder includes a time-to-digital converter for detecting the plurality of detection signal pulses to form the single photon time code sequence.

In some examples, each detector includes a plurality of single photon avalanche photodiodes for respectively generating multiple detection signals in response to the received light signal;

each acquisition unit further comprises a combination logic circuit, wherein the combination logic circuit is used for carrying out logic operation on the multipath detection signals to obtain optimized detection signals; the recorder is configured to detect the optimized detection signal to form the single photon time code sequence.

In some examples, the ranging system further comprises a transmitter for emitting the pulses of signal light to the target.

At least one embodiment of the present disclosure also provides a ranging apparatus comprising a processor and a memory. The memory has stored therein computer executable code which, when executed by the processor, performs the ranging method provided by any of the above embodiments.

The ranging method, the ranging system and the ranging device provided by the embodiment of the disclosure can effectively reduce the interference of ambient light and improve the ranging accuracy.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following description will briefly introduce the drawings that are required to be used in the embodiments or the related technical descriptions, and it is apparent that the drawings in the following description relate only to some embodiments of the present disclosure and are not limiting to the present disclosure.

FIG. 1 is a flow chart of a ranging method provided by at least one embodiment of the present disclosure;

FIG. 2A is a schematic diagram of a ranging system according to at least one embodiment of the present disclosure;

FIGS. 2B and 2C schematically illustrate a received optical signal and a detection signal, respectively, provided by at least one embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a time to digital converter according to at least one embodiment of the present disclosure;

FIG. 4 shows a schematic diagram of a histogram;

FIGS. 5A-5C are schematic structural diagrams of ranging systems provided in some embodiments of the present disclosure; and

Fig. 6 is a schematic diagram of a ranging apparatus according to at least one embodiment of the present disclosure.

Detailed Description

The technical solutions of the embodiments of the present disclosure will be clearly and fully described below with reference to non-limiting example embodiments shown in the drawings and detailed in the following description, more fully explaining example embodiments of the disclosure and their various features and advantageous details. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale. Descriptions of well-known materials, components, and processing techniques are omitted so as to not obscure the example embodiments of the present disclosure. The examples are presented merely to facilitate an understanding of the practice of the example embodiments of the disclosure and to further enable those of skill in the art to practice the example embodiments. Thus, these examples should not be construed as limiting the scope of the embodiments of the disclosure.

Unless defined otherwise, technical or scientific terms used in this disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed. The embodiments of the present disclosure and features of the embodiments may be combined with each other to arrive at new embodiments without conflict.

Typically, in direct time-of-flight measurement techniques, a combination of a single photon avalanche photodiode (Single Photon Avalanche Diode, SPAD) and a time-to-digital conversion circuit (Time toDigital Converter, TDC) can accomplish basic single photon ranging. However, due to the high sensitivity of SPADs, a saturation state is reached upon successful detection of one photon, and a subsequent arrival of a photon will not be responded to within a dead time thereafter. The detection is typically performed only once in one target light emission period, in which case SPADs are easily occupied by ambient light arriving first and target photons cannot be detected.

One method is to delay the response time of the SPAD by a time gating circuit so as to filter out the environmental photons which arrive first and improve the detection probability of the target signal photons. However, since the arrival time of the eye signal photon is not determined, the target signal photon may be located outside the time gate without being detected, and thus the detection efficiency and accuracy are low.

At least one embodiment of the present disclosure provides a ranging method, including: detecting a plurality of received optical signals and forming a plurality of single photon time code sequences, respectively, comprising: detecting a plurality of light pulses in each received light signal and forming a single photon time code sequence, wherein each received light signal comprises an ambient light signal and a signal light pulse reflected by a target object; counting a plurality of the plurality of single photon time code sequences to form a histogram; and carrying out peak searching operation on the histogram to determine the distance of the target object.

In the ranging method provided in at least one embodiment of the present disclosure, a plurality of responses are performed on each received optical signal so as to detect a plurality of optical pulses (i.e., N optical pulses, where N is a positive integer greater than or equal to 2), so as to increase the probability of detecting the target signal photon, where the probability increases as the value of N increases. When the detection results of the plurality of detection periods are counted, since the time position of the signal light pulse in each detection period in the histogram is relatively fixed as compared with the randomly distributed ambient light, a signal peak is exhibited in the histogram finally formed from the single-photon time code sequence, thereby detecting the time of flight t of the signal photon. The depth or distance D of the target can be regarded as half the distance the photon is flying at this time of flight, i.e. d= (c×t)/2, where c is the speed of light. For example, N can range from 2 to 100. For example, the number of detections (period) is greater than 5000.

Compared with the scheme of setting the time gating circuit, the ranging method provided by the embodiment of the disclosure has lower requirements on circuit design and higher detection efficiency and accuracy. Compared with single photon detection in each detection period, the ranging method provided by the embodiment of the disclosure can effectively reduce the interference of ambient light and improve the detection probability, thereby improving the detection accuracy.

For example, the control circuit of the photodetector may be configured such that the photodetector responds multiple times in one detection cycle, thereby enabling detection of multiple light pulses. For example, the photodetector may be implemented as a single photon avalanche diode (Single Photon Avalanche Diode, SPAD) or an avalanche photodiode (AVALANCHE PHOTON DIODE, APD), the embodiments of the disclosure are not limited to a particular type of photodetector.

A received optical signal here refers to an optical pulse train including a plurality of optical pulses received in one detection period, the optical pulse train including a signal optical pulse as a detection target and one or more ambient optical pulses. In each detection period, the plurality of light pulses detected by the photodetector may or may not include signal light pulses, i.e., the plurality of light pulses detected are ambient light pulses. For example, the length of each detection period may cover one or more signal light pulse emission periods. Each received optical signal includes one or more pulses of signal light.

It should be noted that the number (N) of light pulses detected in each detection period is greater than 1, and they may be the same or different, depending on the configuration of the control circuit of the photodetector and the response performance of the photodetector.

Fig. 1 is a flowchart of a ranging method according to at least one embodiment of the present disclosure, fig. 2A is a schematic structural diagram of a ranging system according to at least one embodiment of the present disclosure, fig. 2B schematically illustrates 5 received optical signals (01-05), and fig. 2C schematically illustrates 5 detection signals obtained after the 5 received optical signals are responded to. Ranging methods and ranging systems provided in accordance with at least some embodiments of the present disclosure are described below in connection with fig. 1 and 2A-2C.

As shown in fig. 1, the ranging method includes steps S11 to S13: detecting a plurality of received optical signals and forming a plurality of single photon time code sequences, respectively, comprising: detecting a plurality of light pulses in each received light signal and forming a single photon time code sequence; each received light signal comprises an ambient light signal and a signal light pulse reflected by the target object; counting a plurality of single photon time code sequences corresponding to a plurality of received light signals to form a histogram; and carrying out peak searching operation on the histogram to determine the distance of the target object.

For example, as shown in fig. 2B, 5 received light signals (01-05) each including a signal light pulse (from an elliptical circle) reflected by the object and a plurality of ambient light pulses are received in 5 detection periods, respectively. For example, only two light pulses (circled by a dashed rectangular frame) in the received light signal can be detected in each detection period, and then in the 4 th detection period, the signal light pulse is not detected. But this situation has no effect on the statistics. The time of flight of the photons of each light pulse is detected and converted to a time code to form the single photon time code sequence, from which a histogram is then drawn. When a histogram is formed by counting the single photon time code sequences of a plurality of detection periods, since the time position of the signal light pulse in each detection period in the histogram is relatively fixed compared with the random distribution of the ambient light, a signal peak is shown in the histogram finally formed according to the single photon time code sequence, thereby detecting the time of flight t of the signal photon.

For example, a plurality of detection signal pulses are generated by a single photon avalanche photodiode (Single Photon Avalanche Diode, SPAD) in response to a plurality of light pulses in the received light signal at each detection period.

In each detection cycle, SPAD responds multiple times to detect multiple light pulses. SPAD is used as a single photon detector, and only one photon can be detected at a time, and then the SPAD can be "revived" for the next detection after a dead time. If the SPAD is detected only once in one detection period, the probability of being preempted by the ambient light is high; if the detection is carried out for a plurality of times, the probability of matching with the arrival time of the signal light pulse is greatly improved due to the uncertainty of the revival time of the SPAD, so that the detection probability is improved.

The plurality of detection signal pulses are detected, for example, by one or more time-to-digital converters to form the single photon time code sequence.

Referring in conjunction to fig. 2A, the ranging system includes a collector 110 and a processing circuit 120. For example, the ranging system may also include a light source 130. The light source 130 is used to emit pulses of signal light to the target 15. For example, the signal light pulses are emitted at a certain period or frequency; in other examples, the emission period of the signal light pulses may also be regularly or randomly staggered. The embodiments of the present disclosure are not limited in this regard.

For example, the light source 130 may be a light source such as a Light Emitting Diode (LED), an Edge Emitting Laser (EEL), a Vertical Cavity Surface Emitting Laser (VCSEL), or an array light source composed of a plurality of light sources; for example, the light source 130 may be a VCSEL array light source chip that generates a plurality of VCSEL light sources on a monolithic semiconductor substrate to form. The light beam emitted by the light source 130 may be visible light, infrared light, ultraviolet light, etc. The light source 130 emits a light beam outwards under the control of the processing circuit 120, for example, in one embodiment, the light source 130 emits signal light pulses at a frequency (or pulse period) under the control of the processing circuit 120, which can be used in Direct time of flight (Direct TOF) measurements; for example, the transmission frequency may be set according to the measurement distance, for example, may be set to 1MHz to 100MHz; for example, the measurement distance is in the range of several meters to several hundred meters, for example in the range of 50 meters or 20 meters.

The collector 110 is configured to detect a plurality of received optical signals to form a plurality of single photon time code sequences. Each received light signal comprises an ambient light signal and a signal light pulse reflected by the object. Specifically, the collector 110 is configured to detect a plurality of light pulses in each received light signal, and detect a time of flight of photons of each light pulse and convert the time code into a single photon time code sequence. For example, a plurality of single photon time codes obtained for each detection period are input together to the processing circuit 120.

The processing circuit 120 is connected to the collector 110, and is configured to count a plurality of single photon time code sequences corresponding to a plurality of received light signals to form a histogram, and perform a peak searching operation on the histogram to determine a distance of the target object. For example, the processor 12 may be a separate dedicated circuit, such as a dedicated SOC chip, an FPGA chip, an ASIC chip, or the like, or may include a general purpose processor, such as when the ranging system is integrated into a smart terminal, such as a cell phone, television, computer, or the like, with the processing circuit 120 being at least a portion of the processor in the terminal.

For example, the collector 110 includes a plurality of collection units 10 configured to detect a plurality of received light signals, respectively, and form a plurality of single photon time code sequences for statistical formation into a histogram. This arrangement can increase the probability of detection and reduce the randomness of the histogram statistics. For example, the plurality of acquisition units 10 are arranged in an array.

For example, each acquisition unit 10 includes a detector 11 and a recorder 12, the detector 11 being configured to detect a plurality of light pulses in a corresponding received light signal to generate a plurality of detection signal pulses; the recorder 12 is connected to the detector 11 for detecting the plurality of detection signal pulses to form the single photon time code sequence and outputting to the processing circuit 120.

Fig. 2C schematically shows the multiple received optical signals 01'-05' of fig. 2B being responded to by the detector 11, e.g. each detection signal comprises two detection signal pulses, i.e. the detector 11 responds twice for each detection period, detecting two photons.

For example, the detector 11 comprises a single photon detector, such as a single photon avalanche photodiode (Single Photon Avalanche Diode, SPAD). In each detection cycle, SPAD responds multiple times to detect multiple light pulses. SPAD is used as a single photon detector, and only one photon can be detected at a time, and then the SPAD can be "revived" for the next detection after a dead time. If the SPAD is detected only once in one detection period, the probability of being preempted by the ambient light is high; if the detection is carried out for a plurality of times, the probability of matching with the arrival time of the signal light pulse is greatly improved due to the uncertainty of the revival time of the SPAD, so that the detection probability is improved.

For example, the recorder 12 includes a single photon counter that can detect the time of flight of a single photon. For example, the recorder 12 includes a time-to-digital conversion circuit (Time to Digital Converter, TDC).

The TDC is configured to determine a time of flight of photons from being emitted to being received based on the photodetection signal and generate a time code (binary code, temperature code, etc. code) characterizing the time of flight as corresponding memory cells (also referred to as time bins (bins)) in a histogram memory in the address addressing processing circuit 120, each memory cell being configured to record a photon count value corresponding to the time of flight characterized by the time code for addressing the memory cell, each memory cell being addressed once by 1. The plurality of optical pulses in each detection period form a single photon time code sequence corresponding to the plurality of time codes formed. After a number of cycles of detection, the resulting plurality of single photon time code sequences may be counted and a histogram drawn. The abscissa of the histogram represents the time corresponding to each memory cell, and the ordinate of the histogram represents the photon count value. Since the time position of the signal light pulse in each detection period is relatively fixed in the histogram compared to the randomly distributed ambient light, the peak value can be determined by the peak finding operation based on the histogram to determine the time of flight corresponding to the signal light pulse.

The TDCs are devices that record the time interval between the start signal and the end signal, e.g., each TDC is triggered by a separate start signal and end signal, by which the time of flight of the signal light pulse is obtained, and the time of flight is converted into a time code for output to the processing circuit 120.

In at least some embodiments of the present disclosure, the TDC may be implemented as a single pulse edge detector; in at least some embodiments of the present disclosure, the TDC may function as a multi-edge detector. As shown in fig. 2C, the TDC detects a rising edge (e.g., elliptical circle) of the detection signal pulse output from the detector and converts the rising edge into a responsive time code for output to the processing circuit 120.

Fig. 3 exemplarily shows a partial circuit schematic diagram of a TDC, and a driving method of the TDC provided by an embodiment of the present disclosure is exemplarily described below with reference to fig. 3, which is not, however, a limitation of the embodiment of the present disclosure.

As shown in fig. 3, the TDC circuit includes a delay chain composed of a plurality of delay units and a plurality of flip-flops, for example, D flip-flops, connected to the delay chain. The output end of each delay unit is correspondingly connected with the input end of one D trigger. For example, the input of the delay chain is configured to receive the detection signal output by the detector 11 as a start trigger signal; the clock control terminals of the plurality of D flip-flops are connected to each other and configured to receive a termination trigger signal.

For example, when the termination trigger signal reaches the clock control end of each trigger, the data collected by the register is 1111_1111_0000_0000, which means that 8 delay units are transferred to the right along the rising edge of the detection signal pulse, if the delay time of each delay unit is τ, the time interval between the start trigger signal and the termination trigger signal is 8τ, and the corresponding flight time is T-8τ. The TDC circuitry then converts the resulting time of flight to a time code for output to processing circuitry 120 for forming a histogram.

The TDC circuit may also be used to detect a multi-edge signal. For example, when the termination trigger signal reaches the clock control end of each trigger, the data collected by the register is 1111_0000_1111_0000, which means that rising edges of two detection signal pulses are detected, wherein 12 delay units are transmitted to the right, 4 delay units are transmitted to the right, and the respective corresponding flight times are T-12τ and T-4τ respectively. The TDC circuitry then converts the resulting plurality of time of flight to a plurality of time codes for output to processing circuitry 120 for forming a histogram.

Fig. 4 shows an exemplary diagram of a histogram. As shown in fig. 4, the abscissa of the histogram represents the time corresponding to each storage unit, and Δt refers to the width of the time bin; the ordinate of the histogram represents photon count values, i.e. photon count values stored in each time bin. T1, T2 refer to the start and end moments of the histogram plot, respectively, [ T1, T2] is the time interval of the histogram, and t=t2-T1 refers to the total time width. Based on the histogram, the position of the pulse waveform can be determined by using a method such as a highest peak method, and the corresponding flight time t can be obtained.

For example, in some examples, detecting each received optical signal and forming one single photon time code sequence includes: a plurality of detection signal pulses are generated by a single photon avalanche photodiode in response to a plurality of light pulses in the received light signal and detected by a plurality of time-to-digital converters, respectively, to form the single photon time code sequence.

In this example, each TDC is configured to detect one detection signal pulse. For example, the received plurality of detection signal pulses may be respectively distributed to a plurality of TDCs by a pulse distribution circuit.

For example, in other examples, detecting each received optical signal and forming a single photon time code sequence includes: a plurality of detection signal pulses are generated by a single photon avalanche photodiode in response to a plurality of light pulses in the received light signal and detected by a time to digital converter to form the single photon time code sequence.

In this example, each TDC is used to detect a plurality of detection signal pulses, contributing to simplification of the circuit.

For example, in still other examples, detecting each received optical signal and forming one single photon time code sequence includes: generating a plurality of paths of detection signals by a plurality of single photon avalanche photodiodes in response to the received light signals, and carrying out logic operation on the plurality of paths of detection signals to obtain optimized detection signals; the optimized detection signal is detected to form the single photon time code sequence. For example, the logical operation includes at least one of an and operation, or operation.

For example, when the ambient light is strong, the influence of the ambient light can be reduced by performing an AND operation on the multi-path detection signals measured in each detection period to eliminate some ambient light pulses.

For example, when the signal light pulse emitted from the light source is weak, the detection probability of the signal light pulse can be improved by the or operation.

For example, the logical operations may also include a combination of operations, or operations, to reduce environmental interference and increase the probability of detection of signal light.

The ambient light may be considered here to be distributed as discrete ambient light pulses whose density increases with increasing ambient light intensity.

Fig. 5A-5C respectively illustrate schematic structural diagrams of several ranging systems provided by some embodiments of the present disclosure.

For example, as shown in fig. 5A, there are 4 acquisition units 10, each acquisition unit 10 including a detector 11 and a recorder 12, each detector 11 including a SPAD, and a SPAD control circuit (not shown), such as a quenching circuit, etc. The control circuit is configured to control the SPAD to generate a plurality of detection signal pulses in response to a plurality of light pulses in the received light signal at each detection period. Each recorder 12 comprises a pulse distribution circuit 17 for distributing a plurality of detection signal pulses output by SPADs to a plurality of TDCs, respectively, each TDC for detecting a corresponding detection signal pulse to measure the time of flight of a corresponding light pulse and converting the time of flight to a time code to form a single photon time code sequence. Two TDCs are exemplarily shown in the figure. Here each TDC is used only for single pulse edge detection.

In other examples, as shown in fig. 5B, the main difference between this embodiment and the embodiment shown in fig. 5A is that each recorder 12 includes only one TDC, i.e. multiple detection signal pulses are detected by one TDC to form a single photon time code sequence, where each TDC is used for the detection of multiple pulse edges.

In still other examples, as shown in fig. 5C, each detector 11 includes a plurality of SPADs that are each configured to generate a multiplexed detection signal in response to a received optical signal. Each path of detection signal comprises a plurality of detection signal pulses. The detection probability can be effectively improved by arranging a plurality of SPAD to detect the received optical signals received each time.

Each acquisition unit 10 further comprises a combinational logic circuit 18, and the combinational logic circuit 18 is configured to perform logic operation on multiple detection signals to obtain optimized detection signals, where each detection signal includes multiple detection signal pulses. For example, the optimized detection signal comprises a plurality of optimized detection signal pulses. The recorder 12 is configured to detect the optimized plurality of detection signal pulses to form the single photon time code sequence. For example, each recorder 12 may include one TDC or a plurality of TDCs.

For example, the combinational logic circuit 18 may include an AND circuit or an OR circuit to AND or OR the multiplexed detection signals.

As shown in fig. 6, at least one embodiment of the present disclosure further provides a ranging apparatus 500 comprising a memory 520 and a processor 510, the memory 520 having stored therein computer executable code which, when executed by the processor 510, performs the ranging method provided by any of the above embodiments.

For example, the processor 510 may be a Central Processing Unit (CPU), a Digital Signal Processor (DSP), an image processor (GPU) or other form of processing unit with data processing capabilities and/or instruction execution capabilities, may be a general-purpose processor or a special-purpose processor, and may control other components in the ranging device to perform desired functions.

For example, the memory 520 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and/or non-volatile memory. The volatile memory may include, for example, random Access Memory (RAM) and/or cache memory (cache), and the like. The non-volatile memory may include, for example, read Only Memory (ROM), hard disk, flash memory, and the like. One or more computer program instructions may be stored on a computer readable storage medium that can be executed by a processor to perform the functions of the disclosed embodiments (as implemented by the processor) and/or other desired functions, such as ranging methods, etc. Various applications and various data may also be stored in the computer readable storage medium.

At least one embodiment of the present disclosure also provides a storage medium storing non-transitory computer program instructions that, when executed by a computer, may implement the ranging method of any of the embodiments of the present disclosure. For example, the storage medium may be applied to the distance measuring device described above.

The foregoing is merely exemplary embodiments of the present disclosure and is not intended to limit the scope of the disclosure, which is defined by the appended claims.

Claims

1. A ranging method, comprising:

detecting a plurality of received optical signals and forming a plurality of single photon time code sequences, respectively, comprising: detecting a plurality of light pulses in each received light signal and forming a single photon time code sequence, wherein each received light signal comprises an ambient light signal and a signal light pulse reflected by a target object;

counting the plurality of single photon time code sequences to form a histogram; and

And carrying out peak searching operation on the histogram to determine the distance of the target object.

2. The ranging method of claim 1, wherein detecting each received optical signal and forming a single photon time code sequence comprises:

A plurality of detection signal pulses are generated by a single photon avalanche photodiode in response to a plurality of light pulses in the received light signal and detected by a plurality of time-to-digital converters, respectively, to form the single photon time code sequence.

3. The ranging method of claim 1, wherein detecting each received optical signal and forming a single photon time code sequence comprises:

a plurality of detection signal pulses are generated by a single photon avalanche photodiode in response to a plurality of light pulses in the received light signal and detected by a time to digital converter to form the single photon time code sequence.

4. The ranging method of claim 1, wherein detecting each received optical signal and forming a single photon time code sequence comprises:

Generating a plurality of paths of detection signals by a plurality of single photon avalanche photodiodes in response to the received light signals, and carrying out logic operation on the plurality of paths of detection signals to obtain optimized detection signals;

the optimized detection signal is detected to form the single photon time code sequence.

5. The ranging method of claim 4, wherein the logical operation comprises an and operation, an or operation, or a combination of an and operation and an or operation.

6. A ranging system, comprising:

a collector for detecting a plurality of light pulses in each received light signal and forming a single photon time code sequence to detect the plurality of received light signals to form a plurality of single photon time code sequences, wherein each received light signal comprises an ambient light signal and a signal light pulse reflected by a target object; and

And the processing circuit is connected with the collector and is used for counting the plurality of single photon time code sequences to form a histogram and carrying out peak searching operation on the histogram to determine the distance of the target object.

7. The ranging system of claim 6, wherein the collector comprises a plurality of collection units configured to detect a plurality of received light signals and form a plurality of single photon time code sequences, respectively;

each acquisition unit comprises a detector and a recorder;

The detector is used for detecting a plurality of light pulses in the corresponding received light signals to generate a plurality of detection signal pulses;

The recorder is used for detecting the plurality of detection signal pulses to form the single photon time code sequence and outputting the single photon time code sequence to the processing circuit.

8. The ranging system of claim 7, wherein each detector comprises a single photon avalanche photodiode for generating a plurality of detection signal pulses in response to a plurality of light pulses.

9. The ranging system of claim 8, wherein each recorder comprises a time-to-digital converter and a pulse distribution circuit for distributing the plurality of detection signal pulses to the plurality of time-to-digital converters, respectively;

Each time-to-digital converter is configured to detect a corresponding detection signal pulse to form the single photon time code sequence.

10. The ranging system of claim 8, wherein each recorder comprises a time-to-digital converter for detecting the plurality of detection signal pulses to form the single photon time code sequence.

11. The ranging system of claim 7, wherein each detector comprises a plurality of single photon avalanche photodiodes for respectively generating multiple detection signals in response to the received light signal;

Each acquisition unit further comprises a combination logic circuit, wherein the combination logic circuit is used for carrying out logic operation on the multipath detection signals to obtain optimized detection signals;

The recorder is configured to detect the optimized detection signal to form the single photon time code sequence.

12. A ranging apparatus, comprising:

A processor, and

A memory, wherein the memory has stored therein computer executable code which, when executed by the processor, performs the ranging method of any of claims 1-5.