A flight time statistics device, method and laser ranging system

Abstract

This application provides a flight time statistics device, method, and laser ranging system. The statistics device includes a dual-port read / write memory and a single-port read / write memory. The dual-port read / write memory stores a first accumulated data set for the current integration period. The first accumulated data set includes first accumulated photon count values ​​for M flight times, where the first accumulated photon count value for each flight time is the sum of the K-1 initial photon count values ​​corresponding to the flight time within the first K-1 statistical periods of the K statistical periods of the current integration period. The single-port read / write memory stores a second accumulated data set in the Kth statistical period. The second accumulated data set includes second accumulated photon count values ​​for M flight times, where the second accumulated photon count value for each flight time is the sum of the first accumulated photon count value for the flight time and the initial photon count value corresponding to the Kth statistical period. This addresses the technical problem of the large size of laser ranging systems.

Description

Technical Field

[0001] This application relates to the field of laser ranging technology, and in particular to a time-of-flight statistics device and a laser ranging system. Background Technology

[0002] Laser ranging systems utilize Time-of-Flight (TOF) measurement technology to measure the distance between a target object and the laser ranging system. They have important applications in various 3D ranging and 3D imaging fields, such as autonomous driving, facial recognition, and 3D games. Specifically, a laser ranging system includes multiple time-of-flight statistical devices, each corresponding to a pixel unit. The pixel unit receives the echo beam reflected from the target object, and the time-of-flight statistical devices calculate the time-of-flight data between the emitted beam and the echo beam received by the corresponding pixel unit to obtain the distance to the target.

[0003] Existing time-of-flight (TOF) statistics devices typically include two dual-port random access memories (RAMs). These two RAMs are used alternately as a TOF data overlay memory and a TOF data output memory across multiple time frames to perform statistical analysis on the TOF data acquired within each time frame. However, dual-port RAMs are relatively large, and the number of dual-port RAMs in laser ranging systems is often significant, resulting in a large overall system size. Summary of the Invention

[0004] This application provides a flight time statistics device, method, and laser ranging system, which can solve the technical problem of the large size of existing laser ranging systems to a certain extent.

[0005] In a first aspect, embodiments of this application provide a flight time statistics device, including: a dual-port read / write memory and a single-port read / write memory;

[0006] The dual-port read / write memory is used to store the first accumulated data set within the current integration period; the current integration period includes K statistical periods, each statistical period includes M flight moments, the first accumulated data set includes the first accumulated photon count value of the M flight moments, and the first accumulated photon count value of each flight moment is the sum of the K-1 initial photon count values ​​corresponding to the flight moment within the first K-1 statistical periods of the K statistical periods; K≥2, K is an integer, M≥1, M is an integer;

[0007] The single-port read / write memory is used to store a second accumulated data set in the Kth statistical period within the current integration period; the second accumulated data set includes the second accumulated photon count values ​​of the M flight times, and the second accumulated photon count value of each flight time is the sum of the first accumulated photon count value of the flight time and the initial photon count value corresponding to the Kth statistical period.

[0008] In one possible implementation, the dual-port read / write memory includes M first storage units corresponding one-to-one with the M flight times; the m-th first storage unit among the M first storage units is used to store the sum of the k initial photon count values ​​corresponding to the m-th flight time in the k-th statistical period within the first K-1 statistical periods, where 2≤k≤K-1, 1≤m≤M.

[0009] In one possible implementation, the dual-port read / write memory includes a first port and a second port; the first port is used to read the current accumulated photon count value stored in the m-th first storage unit among the M first storage units during the m-th flight time in the k-th statistical period, wherein the current accumulated photon count value is the sum of the k initial photon count values ​​corresponding to the m-th flight time; the second port is used to write the sum of the initial photon count value of the m-th flight time and the current accumulated photon count value into the m-th first storage unit during the m-th flight time in the k-th statistical period.

[0010] In one possible implementation, the single-port read / write memory includes M second storage units corresponding one-to-one with the M flight times; the m-th second storage unit among the M second storage units is used to store the second accumulated photon count value corresponding to the m-th flight time in the K-th statistical period.

[0011] In one possible implementation, the single-port read / write memory includes a third port; the first port is further configured to read the first accumulated photon count value stored in the m-th first storage unit among the M first storage units at the m-th flight time within the K-th statistical period; the third port is configured to write the sum of the initial photon count value of the m-th flight time and the first accumulated photon count value stored in the m-th first storage unit into the m-th second storage unit at the m-th flight time within the K-th statistical period.

[0012] In one possible implementation, the flight time statistics device further includes a denoising unit; the third port is also used to output the second accumulated data set to the denoising unit for the first K-1 statistical periods in the next integration period of the current integration period.

[0013] Secondly, embodiments of this application provide a flight time statistics method, including:

[0014] Within the current integration period, for each of the K statistical periods, an initial flight time data set is obtained. The initial flight time data set includes M initial photon count values ​​corresponding one-to-one with M flight times, where K≥2, K is an integer, and M≥1, M is an integer.

[0015] In the first K-1 statistical periods of the K statistical periods, the K-1 initial photon count values ​​corresponding to the same flight time in the first K-1 statistical periods are accumulated to obtain a first accumulated flight time data set, and the first accumulated flight time data set is stored in a dual-port read-write memory;

[0016] In the Kth statistical period of the K statistical periods, the initial flight time data set of the Kth statistical period is accumulated with the first accumulated flight time data set to obtain the second accumulated flight time data set, and the second accumulated flight time data set is stored in a single-port read-write memory;

[0017] The first accumulated flight time data set includes M first accumulated photon count values ​​corresponding one-to-one with the M flight times; the second accumulated flight time data set includes M second accumulated photon count values ​​corresponding one-to-one with the M flight times, and the second accumulated photon count value for each flight time is the sum of the first accumulated photon count value for the flight time and the initial photon count value corresponding to the Kth statistical period.

[0018] In one possible implementation, the method further includes: reading the second accumulated flight time data set during the first K-1 statistical periods in the next integration period of the current integration period, and transmitting the second accumulated flight time data set to the denoising unit.

[0019] Based on this possible implementation, after transmitting the second accumulated flight time data set of the current integration period to the denoising unit in the first K-1 statistical cycles of the next integration period, the data stored in the single-port read / write memory can be cleared so that the second accumulated flight time data of the integration period can be received in the Kth statistical cycle of the next integration period.

[0020] Thirdly, embodiments of this application provide a laser ranging system, including: the time-of-flight statistics device described in any one of the first aspects above.

[0021] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method as described in any of the second aspects above.

[0022] Fifthly, embodiments of this application provide a computer program product that, when run on a laser ranging system, causes the laser ranging system to perform any of the methods described in the second aspect above.

[0023] The beneficial effects of the embodiments in this application compared with the prior art are:

[0024] The flight time statistics device provided in this application includes a dual-port read / write memory and a single-port read / write memory. The dual-port read / write memory is used to store the first accumulated photon count value for the first K-1 statistical periods within the integration period. Each first accumulated photon count value is the sum of the initial flight time data corresponding to the same flight moment within the first K-1 statistical periods. The single-port read / write memory is used to store the initial flight time data corresponding to each flight moment and the sum of the first accumulated photon count value in the last statistical period within the integration period, thereby storing the second accumulated photon count value within one integration period into the single-port read / write memory. The volume of the single-port read / write memory is 1 / 3 to 1 / 2 smaller than that of the dual-port read / write memory. By reducing the volume of each flight time statistics device, the volume of the laser ranging system is reduced. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a laser ranging system provided in an embodiment of this application.

[0027] Figure 2 This is a schematic diagram of the workflow of an existing flight time statistics device provided in an embodiment of this application.

[0028] Figure 3 This is a timing diagram of the integration period provided in the embodiments of this application.

[0029] Figure 4This is a schematic diagram of the structure of a flight time statistics device provided in an embodiment of this application.

[0030] Figure 5 This is a schematic diagram of the initial flight time data within an integration period provided in an embodiment of this application.

[0031] Figure 6 This is a schematic diagram of the working process of the flight time statistics device provided in the embodiments of this application.

[0032] Figure 7 This is a schematic diagram illustrating the storage of initial flight time data within an integration cycle in a dual-port read / write memory and a single-port read / write memory, as provided in an embodiment of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] See Figure 1 This is a schematic diagram of a laser ranging system provided in an embodiment of this application. In this embodiment, the laser ranging system includes a light-emitting unit 100, at least one pixel unit 200, at least one time-to-digital converter 300 corresponding to at least one pixel unit 200, and at least one time-of-flight counting device 400.

[0035] Specifically, the light-emitting unit 100 is used to emit laser pulse signals towards the target object within the detection area. Generally, a laser ranging system scans the detection area according to a fixed integration period, and within one integration period, the light-emitting unit can be controlled to emit multiple laser pulse signals towards the detection area.

[0036] The laser ranging system includes one or more pixel units 200. Each pixel unit 200 is used to receive the echo laser signal reflected by the target object within the detection area after each pulse signal is emitted by the light-emitting device, and outputs the echo electrical signal. After each laser pulse signal is emitted by the light-emitting unit 100, each pixel unit 200 will receive the corresponding photon event at one or more flight moments within a statistical period. For example, the pixel unit 200 can be a photodiode (PD) or a single photon avalanche diode (SPAD).

[0037] Each time-to-digital converter 300 is used to sample and output the photon events received by the corresponding pixel unit 200 based on the echo electrical signal output by the corresponding pixel unit 200, generating at least one initial time-of-flight data. Each initial time-of-flight data represents a photon event corresponding to a flight moment. The initial time-of-flight data includes a flight moment and an initial photon count value corresponding to that flight moment. The same flight moment within different statistical periods represents the flight time of photons at the same distance. Each time-to-digital converter is also used to transmit the generated initial time-of-flight data to the corresponding time-of-flight statistics device.

[0038] Each time-of-flight (TOF) counting device 400 is used to count and store the received initial TOF data, and to denoise the collected TOF data to filter out noise signals such as ambient light received during the ranging process. The counting method involves superimposing the initial photon count values ​​corresponding to the same flight time within different statistical periods, and storing the superimposed data in the storage unit corresponding to the flight time. The denoised TOF data is used to generate a histogram, and the photon flight time is determined based on the flight time corresponding to the maximum photon count value in the histogram. The photon flight time is used to calculate the distance between the laser ranging system and the target.

[0039] Existing time-of-flight (TOF) counting devices typically include two dual-port read / write memories. For example, a dual-port read / write memory can be a dual-port random access memory (RAM). A dual-port RAM generally includes two ports: one port for reading data from the RAM's storage cells, and the other port for writing data to the RAM. The dual-port RAM can simultaneously perform data read and write functions.

[0040] For example, suppose that the two dual-port RAMs in an existing flight time statistics device are a first dual-port RAM and a second dual-port RAM, respectively. The process by which the existing flight time statistics device performs statistics on the received initial flight time data over multiple integration periods is as follows: Figure 2 As shown, within multiple integration cycles, the first dual-port RAM and the second dual-port RAM alternately serve as the flight time data superposition memory and the flight time data output memory, respectively, according to the order of the integration cycles, to perform statistics on the flight time data acquired within the corresponding time frame.

[0041] For details, please refer to Figure 2 The diagram shows the workflow of an existing flight time statistics device, and Figure 3 The timing diagram shown indicates that before the first integration cycle arrives, the initial data stored in each memory address of the first dual-port RAM and the second dual-port RAM is 0. One integration cycle includes K statistical cycles, and each statistical cycle includes multiple flight moments. At the arrival of the first integration period, the first dual-port RAM, acting as a time-of-flight data overlay memory, acquires the initial flight time data corresponding to each flight moment transmitted by the TDC in chronological order during the first statistical period of the first integration period. This initial data is then overlaid for the first time with the initial data stored at each memory address in the first dual-port RAM. The first overlaid data corresponding to each flight moment is then written back to the corresponding memory address in the first dual-port RAM. In the second statistical period of the first integration period, the initial flight time data corresponding to each flight moment transmitted by the TDC in chronological order during the second statistical period is acquired. This initial data is then overlaid for the second time with the first overlaid data stored at each memory address in the first dual-port RAM. The second overlaid data corresponding to each flight moment is then written back to the corresponding memory address in the first dual-port RAM. This process continues until the last statistical period of the first integration period, i.e., the Kth statistical period. In this last statistical period, the initial flight time data corresponding to each flight moment transmitted by the TDC in the Kth statistical period is acquired in chronological order during the Kth statistical period. This initial data is then overlaid for the final time with the (K-1)th overlaid data stored at each memory address in the first dual-port RAM. The first overlaid data corresponding to each flight moment is then written back to the corresponding memory address in the first dual-port RAM.

[0042] It should be noted that in each statistical cycle of this process, the memory is traversed from the first storage address to the last storage address in the first dual-port RAM according to the flight time sequence. After the last statistical cycle in the first integration cycle ends, each storage address in the first dual-port RAM stores the sum of multiple initial flight time data corresponding to the same flight time in the first integration cycle.

[0043] like Figure 2 As shown, when the second integration cycle arrives, the second dual-port RAM, acting as a flight time data superposition memory, repeatedly executes the following steps in each statistical cycle within the second integration cycle: reading data from the second dual-port RAM, accumulating the read data with the initial flight time data obtained from the TDC within the second integration cycle, and rewriting the accumulated data back into the second dual-port RAM, until the last statistical cycle within the second integration cycle ends. At this point, each storage address in the second dual-port RAM stores the sum of multiple initial flight time data corresponding to the same flight time in all statistical cycles within the second integration cycle.

[0044] During the second integration cycle, the first dual-port RAM, acting as a flight time data output memory, outputs the data superimposed from the first integration cycle—that is, the sum of multiple initial flight time data corresponding to the same flight moment within the first integration cycle—to other processing units. After that, all storage addresses in the first dual-port RAM store 0 data.

[0045] At the arrival of the third integration cycle, the first dual-port RAM serves as a time-of-flight data overlay memory. Until the end of the last statistical cycle within the third integration cycle, each memory address in the first dual-port RAM stores the sum of multiple initial flight time data corresponding to the same flight moment within the third integration cycle. Correspondingly, the second dual-port RAM serves as a time-of-flight data output memory, outputting the data overlaid in the second integration cycle—that is, the sum of multiple initial flight time data corresponding to the same flight moment within the second integration cycle—to other processing units. Afterward, all memory addresses in the second dual-port RAM store zero data. For example, the other processing units could be denoising units to perform denoising processing on the data overlaid in each integration cycle.

[0046] Similarly, in the laser ranging system, the first and second dual-port RAMs of each time-of-flight (TOF) statistical device alternately serve as the TOF data superposition memory and the TOF data output memory, respectively, according to the integration period, to statistically analyze and store the TOF data generated by the corresponding pixel unit in each integration period. However, the large number of ports in the dual-port RAMs results in a large size, and the large number of dual-port RAMs in the laser ranging system also contributes to the overall large size of the laser ranging system.

[0047] To address the aforementioned technical problems, this application provides a flight time statistics device, method, and laser ranging system. The flight time statistics device includes a dual-port read-only memory and a single-port read-only memory. The dual-port read-only memory stores the first accumulated photon count values ​​for the first K-1 statistical periods within each integration period. Each first accumulated photon count value is the sum of the initial flight time data corresponding to the same flight moment within the first K-1 statistical periods. The single-port read-only memory stores the initial flight time data corresponding to each flight moment and the sum of the first accumulated photon count values ​​in the last statistical period within each integration period. The volume of the single-port read-only memory is 1 / 3 to 1 / 2 smaller than that of the dual-port read-only memory, thereby reducing the volume of the laser ranging system.

[0048] The technical solution of this application will be described in detail below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0049] In one possible implementation, refer to, for example Figure 3 The timing diagram shown, and Figure 4 The schematic diagram of the flight time statistics device shown in this application embodiment includes a dual-port read / write memory and a single-port read / write memory. The dual-port read / write memory stores the first accumulated data set within the current integration period. The current integration period includes K statistical periods, each statistical period includes M flight times, and the first accumulated data set includes M first accumulated photon count values ​​corresponding one-to-one with the M flight times. The first accumulated photon count value corresponding to each flight time is the sum of the K-1 initial photon count values ​​corresponding to that flight time within the first K-1 statistical periods of the K statistical periods. K ≥ 2, where K is an integer, and M ≥ 1, where M is an integer.

[0050] The single-port read / write memory is used to store the second accumulated data set in the Kth statistical period within the current integration period. Specifically, the second accumulated data set includes M second accumulated photon count values ​​corresponding one-to-one with M flight times. The second accumulated photon count value corresponding to each flight time is the sum of the first accumulated photon count value corresponding to that flight time and the initial photon count value corresponding to that flight time in the Kth statistical period.

[0051] It should be noted that each statistical period within the current integration period corresponds to an initial flight time data set, and the initial flight time data set corresponding to each statistical period includes M flight time photon count values ​​that correspond one-to-one with M flight times.

[0052] For example, see references to Figure 5 The initial flight time data within an integration period shown is represented as follows: the initial flight time data set for the first statistical period within the current integration period can be represented as {P10, P11, ..., P1[M-1]}, the initial flight time data set for the second statistical period can be represented as {P20, P21, ..., P2[M-1]}, and so on. The initial flight time data set for the (K-1)th statistical period can be represented as {P... K-1 0, P K-1 1、…、P K-1 The initial flight time data set for the Kth statistical period can be represented as {P}. K 0, P K 1、…、P K [M-1]}. Then the first accumulated data set is represented as {P10+P20+…+P K-1 0, P11 + P21 + ... + P K-1 1.…,P1[M-1]+P2[M-1]+…+P K-1 [M-1]}, where P10+P20+…+P K-1 0 represents the first accumulated photon count value corresponding to the first flight time out of M flight times, P11+P21+…+P K-1 1 represents the first accumulated photon count value corresponding to the second flight time out of M flight times, P1[M-1]+P2[M-1]+…+P K-1 [M-1] is an accumulated photon count value corresponding to the (M-1)th flight time out of M flight times. The first accumulated data set is represented as {P10+P20+…+P K-1 0+P K 0, P11 + P21 + ... + P K-1 1+P K 1.…,P1[M-1]+P2[M-1]+…+P K-1 [M-1]+P K [M-1]}, where P10+P20+…+P K-1 0+P K 0 represents the second accumulated photon count value corresponding to the first flight time out of M flight times, P11+P21+…+P K-1 1+P K 1 represents the second accumulated photon count value corresponding to the second flight time out of M flight times, P1[M-1]+P2[M-1]+…+P K-1 [M-1]+P K [M-1] is the double-accumulated photon count value corresponding to the (M-1)th flight time out of the M flight times.

[0053] In this embodiment, the dual-port read / write memory includes M first storage units corresponding one-to-one with M flight times. Specifically, the m-th first storage unit among the M first storage units is used to store the sum of k initial photon count values ​​corresponding to the m-th flight time in the k-th statistical period within the first K-1 statistical periods, where 2≤k≤K-1, 1≤m≤M.

[0054] For example, the storage addresses of the M first storage units in the dual-port read / write memory can be represented as a0, a1, ..., a1, respectively. M-2 a M-1 A dual-port read / write memory can be a dual-port random access memory.

[0055] Specifically, the dual-port read / write memory includes a first port and a second port. The first port can be a data read port, used to read the current accumulated photon count value stored in the m-th first storage unit among M first storage units at the m-th flight time within the k-th statistical period. The current accumulated photon count value is the sum of the k-1 initial photon count values ​​corresponding to the m-th flight time. The second port can be a data write port, used to write the sum of the initial photon count value of the m-th flight time and the current accumulated photon count value into the m-th first storage unit within the k-th statistical period.

[0056] In this embodiment, the single-port read / write memory includes M second storage units corresponding one-to-one with the M flight times. Specifically, the m-th second storage unit among the M second storage units is used to store the second accumulated photon count value corresponding to the m-th flight time in the K-th statistical cycle within the current integration cycle.

[0057] For example, the storage addresses of the M second storage units in a single-port read / write memory can be represented as b0, b1, ..., b... M-2 b M-1 A single-port read / write memory can be a single-port random access memory.

[0058] The single-port read / write memory includes a third port. The single-port read / write memory can only perform data writing or reading functions through the third port at any given time. Specifically, the first port of the dual-port read / write memory is also used to read the first accumulated photon count value stored in the m-th first storage unit among M first storage units during the m-th flight time in the K-th statistical period; the third port of the single-port read / write memory is used to write the sum of the initial photon count value of the m-th flight time and the first accumulated photon count value stored in the m-th first storage unit into the m-th second storage unit during the m-th flight time in the K-th statistical period.

[0059] Furthermore, the flight time statistics device provided in this application embodiment may include an accumulator, which includes two input terminals (i.e., a first input terminal and a second input terminal) and an output terminal. The first input terminal is used to acquire the initial photon count value corresponding to each flight moment in each statistical cycle within the current integration cycle. The second input terminal is used to sequentially point to the read terminals of the M first storage units included in the dual-port read memory in the order of flight moments in each statistical cycle of the current integration cycle. The output terminal of the accumulator is used to sequentially point to the write terminals of the M first storage units included in the dual-port read memory in the order of flight moments in each of the first K-1 statistical cycles of the current integration cycle, and to sequentially point to the write terminals of the M second storage units included in the single-port read memory in the order of flight moments in the Kth statistical cycle of the current integration cycle.

[0060] refer to Figure 6 The schematic diagram of the flight time statistics device shows that, at the m-th flight moment within the k-th statistical period of the K-1 preceding statistical periods of the current integration period, the first input of the accumulator points to the storage address a of the m-th first storage unit in the dual-port read / write memory. m The reading end receives the initial photon count value P at the m-th flight time within the k-th statistical period. k [m-1], the output terminal points to the storage address a of the m-th first storage unit in the dual-port read / write memory. m-1 The write end. Specifically, the first input end of the accumulator can read the current accumulated photon count value P1[m-1]+P2[m-1]+…+P from the m-th first storage cell out of M first storage cells through the first port of the dual-port read / write memory. k-1 [m-1] and the storage address a of the m-th first storage unit. m The data in the middle is cleared, and the initial photon count value P of the m-th flight time in the k-th statistical period is obtained through the second input terminal. k [m-1], the accumulator will accumulate the current photon count value P1[m-1]+P2[m-1]+…+P k-1 [m-1] and the initial photon count value P k After accumulating [m-1], the sum of the two is P1[m-1]+P2[m-1]+…+P k-1 [m-1]+P k [m-1] Rewrite the memory address a corresponding to the m-th first memory unit through the output terminal and the second port of the dual-port memory. m-1 middle.

[0061] Understandably, during the M flight times within the (K-1)th statistical period of the current integration cycle, the first input of the accumulator sequentially points to the read ends of the M first storage units in the dual-port read / write memory according to the flight time order, and sequentially reads the current accumulated photon count value P10+P20+…+P stored in the dual-port read / write memory. K-2 0, P11 + P21 + ... + P K-2 1.…,P1[M-1]+P2[M-1]+…+P K-2 [M-1], and sequentially clear the data stored in the M first storage units; the second input terminal receives the initial photon count values ​​P of the M flight times within the K-1th statistical period in the order of flight times. K-1 0, P K-1 1、…、P K-1 [M-1]; The output terminals point sequentially to the write terminals of the M first memory cells in the dual-port read / write memory according to the flight time sequence.

[0062] like Figure 7 As shown, after the Mth flight moment in the (K-1)th statistical period of the current integration cycle, the data stored in the M first storage units of the dual-port memory is the first accumulated data set, that is, the storage addresses corresponding to the M first storage units of the dual-port memory are a0, a1, ..., a0. M-1 The first accumulated photon count values ​​stored are P10 + P20 + ... + P K-2 0+P K-1 0, P11 + P21 + ... + P K-2 1+P K-1 1.…,P1[M-1]+P2[M-1]+…+P K-2 [M-1]+P K-1 [M-1]

[0063] Furthermore, at the m-th flight moment within the K-th statistical period of the current integration cycle, the first input of the accumulator points to the storage address a of the m-th first storage unit in the dual-port read / write memory. m The reading end receives the initial photon count value P at the m-th flight time within the K-th statistical period. K [m-1], the output terminal points to the storage address b of the m-th second storage unit in the single-port read / write memory. m-1 The write end. Specifically, the first input end of the accumulator can read the first accumulated photon count value P1[m-1]+P2[m-1]+…+P from the m-th first storage cell out of M first storage cells through the first port of the dual-port read / write memory. K-1 [m-1] and the storage address a of the m-th first storage unit. mThe data in the middle is cleared, and the initial photon count value P of the m-th flight time in the K-th statistical period is obtained through the second input terminal. K [m-1], the accumulator will accumulate the current photon count value P1[m-1]+P2[m-1]+…+P K-1 [m-1] and the initial photon count value P K After accumulating [m-1], the sum of the two is P1[m-1]+P2[m-1]+…+P K-1 [m-1]+P K [m-1] Write the memory address b corresponding to the m-th second memory unit through the output terminal and the second port of the single-port memory. m-1 middle.

[0064] Understandably, during the M flight times within the Kth statistical period of the current integration cycle, the first input of the accumulator sequentially points to the read ends of the M first storage units in the dual-port read / write memory according to the flight time order, and sequentially reads the current accumulated photon count value P10+P20+…+P stored in the dual-port read / write memory. K-2 0+P K-1 0, P11 + P21 + ... + P K-2 1+P K-1 1.…,P1[M-1]+P2[M-1]+…+P K-2 [M-1]+P K-1 [M-1], and sequentially clear the data stored in the M first storage units; the second input of the accumulator receives the initial photon count values ​​P of the M flight times within the Kth statistical period in the order of flight times. K 0, P K 1、…、P K [M-1]; The output of the accumulator points sequentially to the write ends of the M second memory units in the single-port read / write memory according to the flight time sequence.

[0065] like Figure 7 As shown, after the Mth flight moment within the Kth statistical period of the current integration cycle, the data stored in the M second storage units of the single-port memory constitutes the second accumulated data set, that is, the storage addresses corresponding to the M second storage units of the single-port memory are b0, b1, ..., b... M-1 The stored second accumulated photon count values ​​are P10 + P20 + ... + P K-2 0+P K-1 0+P K 0, P11 + P21 + ... + P K-2 1+P K-1 1+P K 1.…,P1[M-2]+P2[M-2]+…+PK-2 [M-2]+P K-1 [M-1]+P K [M-1]

[0066] Furthermore, in this embodiment, the flight time statistics device further includes a noise reduction unit. The noise reduction unit is used to read the second accumulated photon count values ​​stored in the M second storage units of the single-port read-write memory sequentially according to the flight time order through the third port of the single-port read-write memory in any one of the first K-1 statistical periods in the next integration period of the current integration period, and to clear the data stored in the M second storage units sequentially.

[0067] As an example and not a limitation, the following description uses two integration cycles as an example to illustrate the specific workflow of the flight time statistics device provided in the embodiments of this application. The specific workflow of the flight time device in two integration cycles includes the following steps:

[0068] Step 1: In the first statistical period of the first integration cycle, the accumulator of the flight time statistics device acquires the initial photon count value P10 corresponding to the first flight time at the first flight moment within the first statistical period at its first input terminal. The second input terminal reads the data 0 stored in the first storage unit from the first port of the dual-port read / write memory. The accumulator adds the initial photon count value P10 corresponding to the first flight moment to 0 and outputs P10. P10 is then rewritten into the first storage unit through the second port of the dual-port read / write memory. In the second flight moment within the first statistical period, the first input terminal acquires the initial photon count value P11 corresponding to the second flight moment. The second input terminal reads the data 0 stored in the second storage unit from the first port of the dual-port read / write memory. The accumulator adds the initial photon count value P11 corresponding to the second flight moment to 0 and outputs P11. P11 is then rewritten into the second storage unit through the second port of the dual-port read / write memory. Similarly, at the Mth flight time within the first statistical period, the first input terminal obtains the initial photon count value P1[M-1] corresponding to the Mth flight time, the second input terminal reads the data 0 stored in the Mth first storage unit from the first port of the dual-port read-write memory, the accumulator adds the initial photon count value P1[M-1] corresponding to the Mth flight time to 0 and outputs P1[M-1], and rewrites P1[M-1] into the Mth first storage unit through the second port of the dual-port read-write memory.

[0069] In the second statistical cycle of the first integration cycle, the accumulator of the flight time statistics device acquires the initial photon count value P20 corresponding to the first flight time at the first flight moment within the second statistical cycle at the first input terminal, and reads the current accumulated photon count value P10 stored in the first storage unit from the first port of the dual-port read-write memory. The accumulator adds the initial photon count value P20 corresponding to the first flight moment to the current accumulated photon count value P10 and outputs P10+P20 at the output terminal, and rewrites P10+P20 into the first storage unit through the second port of the dual-port read-write memory. During the second flight time in the second statistical period, the first input terminal obtains the initial photon count value P21 corresponding to the second flight time, and the second input terminal reads the current accumulated photon count value P11 stored in the second first storage unit from the first port of the dual-port read-write memory. The accumulator adds the initial photon count value P21 corresponding to the second flight time to P11 and outputs P11+P21. Then, P11+P21 is rewritten into the second first storage unit through the second port of the dual-port read-write memory. Similarly, at the Mth flight time within the second statistical period, the first input terminal obtains the initial photon count value P2[M-1] corresponding to the Mth flight time, and the second input terminal reads the current accumulated photon count value P1[M-1] stored in the Mth first storage unit from the first port of the dual-port read / write memory. The accumulator adds the initial photon count value P2[M-1] corresponding to the Mth flight time to P1[M-1] and outputs P1[M-1]+P2[M-1], and rewrites P1[M-1]+P2[M-1] into the Mth first storage unit through the second port of the dual-port read / write memory.

[0070] Until the Kth statistical cycle of the first integration cycle, the accumulator of the flight time statistics device acquires the initial photon count value P corresponding to the first flight time at the first flight moment within the Kth statistical cycle. K 0. The second input terminal reads the first accumulated photon count value P10+P20+…+P from the first port of the dual-port read / write memory. K-1 0, the accumulator will store the initial photon count value P corresponding to the first flight moment. K 0 and the first accumulated photon count value P10+P20+…+P K-1 After accumulating to 0, the output terminal outputs the first and second accumulated photon count values: P10 + P20 + ... + P K-1 0+P K 0, and set the first second accumulated photon count value P10+P20+…+P K-1 0+P K0 is written to the first second storage cell of the single-port read / write memory through the third port of the single-port read / write memory. At the second flight time within the Kth statistical period, the first input terminal acquires the initial photon count value P corresponding to the second flight time. K 1. The second input terminal reads the second first accumulated photon count value P11+P21+…+P from the first port of the dual-port read / write memory. K-1 1. The accumulator sets the initial photon count value P corresponding to the second flight time. K 1 and the second first accumulated photon count value P11+P21+…+P K-1 After accumulation, the output terminal outputs the second accumulated photon count value: P11 + P21 + ... + P K-1 1+P K 1, and the second accumulated photon count value P11+P21+…+P K-1 1+P K 1. The data is written to the second storage unit of the single-port read / write memory through the third port of the single-port read / write memory. Similarly, at the Mth flight time within the Kth statistical period, the first input of the accumulator obtains the initial photon count value P corresponding to the Mth flight time. K [M-1], the second input terminal reads the Mth first accumulated photon count value P1[M-1]+P2[M-1]+…+P from the first port of the dual-port read / write memory. K-1 [M-1], the accumulator will store the initial photon count value P corresponding to the Mth flight time. K [M-1] and the Mth first accumulated photon count value P1[M-1]+P2[M-1]+…+P K-1 After accumulating [M-1], the output terminal outputs the Mth second accumulated photon count value: P1[M-1]+P2[M-1]+…+P K-1 [M-1]+P K [M-1], and the Mth second accumulated photon count value P1[M-1]+P2[M-1]+…+P K-1 [M-1]+P K [M-1] is written to the Mth second storage unit of the single-port read-write memory through the third port of the single-port read-write memory.

[0071] After the first integration cycle ends, the data stored in the first storage cell of the dual-port read / write memory is all 0, while the single-port read / write memory stores the M second accumulated photon count values ​​of the first integration cycle.

[0072] Step 2: In the first statistical cycle within the second integration cycle, the denoising unit sequentially reads the M second accumulated photon count values ​​of the first integration cycle stored in the M second storage units of the single-port read / write memory through the third port, and sequentially clears the data in the M second storage units.

[0073] Referring to step one above, in the first statistical period of the second integration cycle, the accumulator of the flight time statistics device acquires the initial photon count value P10 corresponding to the first flight time at the first flight time at the first input terminal, and reads the data 0 stored in the first storage unit from the first port of the dual-port read / write memory. The accumulator adds the initial photon count value P10 corresponding to the first flight time to 0 and outputs P10, and then rewrites P10 into the first storage unit through the second port of the dual-port read / write memory. Similarly, at the Mth flight time in the first statistical period, the first input terminal acquires the initial photon count value P1[M-1] corresponding to the Mth flight time, and the second input terminal reads the data 0 stored in the Mth storage unit from the first port of the dual-port read / write memory. The accumulator adds the initial photon count value P1[M-1] corresponding to the Mth flight time to 0 and outputs P1[M-1], and then rewrites P1[M-1] into the Mth storage unit through the second port of the dual-port read / write memory.

[0074] Until the Kth statistical cycle of the second integration cycle, the accumulator of the flight time statistics device acquires the initial photon count value P corresponding to the first flight time at the first flight moment within the Kth statistical cycle at the first input terminal. K 0. The second input terminal reads the first accumulated photon count value P10+P20+…+P from the first port of the dual-port read / write memory. K-1 0, the accumulator will store the initial photon count value P corresponding to the first flight moment. K 0 and the first accumulated photon count value P10+P20+…+P K-1 After accumulating to 0, the output terminal outputs the first and second accumulated photon count values: P10 + P20 + ... + P K-1 0+P K 0, and set the first second accumulated photon count value P10+P20+…+P K-1 0+P K 0 is written to the first second storage unit of the single-port read / write memory through the third port of the single-port read / write memory. Similarly, at the Mth flight time within the Kth statistical period, the first input of the accumulator obtains the initial photon count value P corresponding to the Mth flight time. K[M-1], the second input terminal reads the Mth first accumulated photon count value P1[M-1]+P2[M-1]+…+P from the first port of the dual-port read / write memory. K-1 [M-1], the accumulator will store the initial photon count value P corresponding to the Mth flight time. K [M-1] and the Mth first accumulated photon count value P1[M-1]+P2[M-1]+…+P K-1 After accumulating [M-1], the output terminal outputs the Mth second accumulated photon count value: P1[M-1]+P2[M-1]+…+P K-1 [M-1]+P K [M-1], and the Mth second accumulated photon count value P1[M-1]+P2[M-1]+…+P K-1 [M-1]+P K [M-1] is written to the Mth second storage unit of the single-port read-write memory through the third port of the single-port read-write memory.

[0075] After the second integration cycle ends, the data stored in the first storage cell of the dual-port read / write memory is all 0, while the single-port read / write memory stores the M second accumulated photon count values ​​of the second integration cycle.

[0076] Based on the flight time counting device provided in the above embodiments, this application also provides a flight time counting method, which includes: acquiring an initial flight time data set for each of the K statistical cycles within the current integration cycle, wherein the initial flight time data set includes M initial photon count values ​​corresponding one-to-one with M flight times, K≥2, where K is an integer, and M≥1, where M is an integer; accumulating the K-1 initial photon count values ​​corresponding to the same flight time within the first K-1 statistical cycles of the K statistical cycles to obtain a first accumulated flight time data set, and storing the first accumulated flight time data set in a dual-port read / write storage. In the device; in the Kth statistical period of K statistical periods, the initial flight time data set of the Kth statistical period is accumulated with the first accumulated flight time data set to obtain the second accumulated flight time data set, and the second accumulated flight time data set is stored in the single-port read-write memory; the first accumulated flight time data set includes M first accumulated photon count values ​​corresponding to M flight times; the second accumulated flight time data set includes M second accumulated photon count values ​​corresponding to M flight times, and the second accumulated photon count value of each flight time is the sum of the first accumulated photon count value of the flight time and the initial photon count value corresponding to the Kth statistical period.

[0077] Optionally, the method further includes: reading the second accumulated flight time data set during the first K-1 statistical cycles in the next integration cycle of the current integration cycle, and transmitting the second accumulated flight time data set to the denoising unit in the flight time statistics device.

[0078] It should be noted that the specific implementation process of the statistical method embodiment can refer to the specific working process of each module in the above statistical device, and will not be repeated here.

[0079] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to 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 embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. Based on the same inventive concept, this application also provides a terminal device.

[0080] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the specific process of the above-described statistical method embodiments.

[0081] This application also provides a computer program product that, when run on a photon counting lidar, enables the photon counting lidar to implement the specific process of the above-described statistical method embodiment.

[0082] If the integrated units described above are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable storage medium can include at least: any entity or device capable of carrying the computer program code to a photographing device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0083] References to "one embodiment" or "some embodiments" as described in this application mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0084] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0085] Furthermore, in this application, unless otherwise expressly specified and limited, the terms "connection" and "linkage" should be interpreted broadly. For example, they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise expressly limited, those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0086] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A flight time statistics device, characterized in that, include: Dual-port read / write memory, single-port read / write memory, and noise reduction unit; The dual-port read / write memory is used to store the first accumulated data set within the current integration period; The current integration period includes K statistical periods, each statistical period includes M flight moments, the first accumulated data set includes the first accumulated photon count value of the M flight moments, and the first accumulated photon count value of each flight moment is the sum of the K-1 initial photon count values ​​corresponding to the flight moment in the first K-1 statistical periods of the K statistical periods, where K≥2, K is an integer, M≥1, and M is an integer; The single-port read / write memory is used to store the second accumulated data set in the Kth statistical period within the current integration period; The second accumulated data set includes the second accumulated photon count values ​​for the M flight times, and the second accumulated photon count value for each flight time is the sum of the first accumulated photon count value for the flight time and the initial photon count value corresponding to the Kth statistical period; The noise reduction unit is used to read the second accumulated photon count value stored in the M second storage units of the single-port read / write memory in any statistical period within the first K-1 statistical periods in the next integration period of the current integration period, according to the order of the M flight times, and to clear the data stored in the M second storage units in sequence.

2. The flight time statistics device according to claim 1, characterized in that, The dual-port read / write memory includes M first storage units that correspond one-to-one with the M flight times; The m-th first storage unit among the M first storage units is used to store the sum of the k initial photon count values ​​corresponding to the m-th flight time in the k-th statistical period within the first K-1 statistical periods, where 2≤k≤K-1 and 1≤m≤M.

3. The flight time statistics device according to claim 2, characterized in that, The dual-port read / write memory includes a first port and a second port; The first port is used to read the current accumulated photon count value stored in the mth first storage unit among the M first storage units during the mth flight time in the kth statistical period. The current accumulated photon count value is the sum of the k initial photon count values ​​corresponding to the mth flight time. The second port is used to write the sum of the initial photon count value and the current accumulated photon count value of the m-th flight time into the m-th first storage unit during the m-th flight time in the k-th statistical period.

4. The flight time statistics device according to claim 3, characterized in that, The single-port read / write memory includes M second storage units that correspond one-to-one with the M flight times; The m-th second storage unit among the M second storage units is used to store the second accumulated photon count value corresponding to the m-th flight time in the K-th statistical period.

5. The flight time statistics device according to claim 4, characterized in that, The single-port read / write memory includes a third port; The first port is also used to read the first accumulated photon count value stored in the m-th first storage unit among the M first storage units during the m-th flight time in the K-th statistical period; The third port is used to write the sum of the initial photon count value of the m-th flight time and the first accumulated photon count value stored in the m-th first storage unit into the m-th second storage unit during the m-th flight time.

6. A method for flight time statistics, characterized in that, include: Within the current integration period, for each of the K statistical periods, an initial flight time data set is obtained. The initial flight time data set includes M initial photon count values ​​corresponding one-to-one with M flight times, where K≥2, K is an integer, and M≥1, M is an integer. In the first K-1 statistical periods of the K statistical periods, the K-1 initial photon count values ​​corresponding to the same flight time in the first K-1 statistical periods are accumulated to obtain a first accumulated flight time data set, and the first accumulated flight time data set is stored in a dual-port read-write memory; In the Kth statistical period of the K statistical periods, the initial flight time data set of the Kth statistical period is accumulated with the first accumulated flight time data set to obtain the second accumulated flight time data set, and the second accumulated flight time data set is stored in a single-port read-write memory; The first accumulated flight time data set includes M first accumulated photon count values ​​corresponding one-to-one with the M flight times; the second accumulated flight time data set includes M second accumulated photon count values ​​corresponding one-to-one with the M flight times, and the second accumulated photon count value for each flight time is the sum of the first accumulated photon count value for the flight time and the initial photon count value corresponding to the Kth statistical period; In any one of the first K-1 statistical periods within the next integration period of the current integration period, the second accumulated photon count value stored in the M second storage units of the single-port read-write memory is read sequentially according to the order of the M flight times, so as to transmit the second accumulated photon count value stored in the M second storage units to the noise reduction unit, and the data stored in the M second storage units is cleared sequentially.

7. A laser ranging device, characterized in that, Includes the flight time statistics device as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in claim 6.

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