A zero point detection method and device for distance detection

Abstract

The application provides a zero point detection method and device for distance detection, the method comprising: a TOF chip continuously sending a control signal to a driving module, when the driving module emits a driving signal to a laser according to the control signal, the TOF chip synchronously receives a zero point electric signal; the TOF chip performs TDC conversion on each received zero point electric signal, and counts on a corresponding time box based on the converted TDC data; the TOF chip accumulates and averages the values of the time boxes according to the counting results of each time box in a specified range, to obtain an average value of the time boxes; and the TOF chip calculates a zero point distance according to the average value of the time boxes. Through the accumulation and averaging of the counting results of the time boxes in the specified range, the data processing amount for calculating the zero point distance is small, the complete histogram and peak searching processing are not required, the storage space and hardware resources occupied by the zero point detection are effectively saved, and the detection cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of distance detection technology, and in particular to a method and apparatus for zero-point detection of distance. Background Technology

[0002] Distance detection technology based on the Time of Flight (TOF) method is currently widely used in 3D modeling, portable electronic devices, AR / VR / MR, robotics, drones, autonomous vehicles and other related fields.

[0003] Time-of-flight distance sensors calculate the distance to a target object by utilizing the time difference between the laser's flight at the transmitting end and its reflection from the target object to the receiving end. Since there is a time difference between the output time of the control signal that controls the laser emission and the actual laser emission time, zero-point detection is required to account for this time difference. This allows the distance measured by subtracting the zero-point distance from the distance reflected back from the target object during ranging, thus obtaining the actual distance to the target object.

[0004] Currently, the usual method is to perform histogram statistics on the laser at the emitting end and find the peak to determine the location of the zero point. This detection method, which performs histogram statistics on the zero point, requires a large amount of storage space and has a complex hardware structure, thus increasing the detection cost. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a zero-point detection method and apparatus for distance detection, which aims to save storage space and hardware resources occupied by zero-point detection and reduce detection costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides a zero-point detection method for distance detection, comprising the following steps:

[0008] The TOF chip continuously sends control signals to the drive module. When the drive module emits drive signals to the laser according to the control signals, the TOF chip synchronously receives the zero-point electrical signal.

[0009] The TOF chip performs TDC conversion on each received zero-point electrical signal and counts the data in the corresponding time bin based on the converted TDC data.

[0010] The TOF chip accumulates and averages the values ​​of each time box within a specified range based on the counting results of each time box, thus obtaining the average value of the time boxes.

[0011] The TOF chip calculates the zero-point distance based on the average value of the time bins.

[0012] In one embodiment, the zero-point electrical signal is specifically:

[0013] When the driving module sends a driving signal to the laser, the TOF chip synchronously receives the driving signal as a zero-point electrical signal.

[0014] In one embodiment, the zero-point electrical signal is specifically:

[0015] When the laser starts emitting laser light, the reference SPAD array of the TOF chip receives the laser light and converts it into a zero-point electrical signal.

[0016] In one embodiment, the step of averaging the values ​​of each timebox based on the count results within a specified range to obtain the average value of the timeboxes includes:

[0017] Read the value of the corresponding time bin for each count based on TDC data;

[0018] Confirm whether the value of the time box belongs to the specified range. If it does, accumulate the value of the time box. If it does not belong, filter out the value of the time box until the accumulation ends.

[0019] The average value of the time bins is obtained by averaging the accumulated results based on the number of accumulations.

[0020] In one embodiment, before averaging the values ​​of the time bins based on the count results of each time bin within a specified range to obtain the average value of the time bins, the method further includes:

[0021] Weighted encoding is performed on the values ​​of each time bin within a specified range to obtain the encoded value of each time bin.

[0022] In one embodiment, accumulating the value of the timebox specifically refers to:

[0023] The encoded values ​​corresponding to the values ​​of the time bins are accumulated to obtain the accumulated encoded value of the time bins.

[0024] In one embodiment, the step of averaging the accumulation results based on the number of accumulations to obtain the average value of the time bins includes:

[0025] The average encoded value of the time bin is obtained by averaging the accumulated values ​​based on the number of accumulations.

[0026] The average encoded value is decoded to obtain the average value of the time bins.

[0027] In one embodiment, the weighted encoding of the values ​​of each time bin within a specified range to obtain the encoded value of each time bin includes:

[0028] Determine the reference time box within the specified range;

[0029] The value of each time box is subtracted from the value of the reference time box to obtain the encoded value of each time box.

[0030] In one embodiment, the specified range is specifically the timebox range corresponding to the preset zero-point distance range.

[0031] A second aspect of the present invention provides a zero-point detection device for distance detection, comprising:

[0032] The control module is used to continuously send control signals to the drive module. When the drive module emits drive signals to the laser according to the control signals, it synchronously receives the zero-point electrical signal.

[0033] The TDC module is used to perform TDC conversion on each received zero-point electrical signal and count the data in the corresponding time bin based on the converted TDC data.

[0034] The data processing module is used to accumulate and average the values ​​of each time box within a specified range based on the counting results of each time box to obtain the average value of the time boxes; and to calculate the zero-point distance based on the average value of the time boxes.

[0035] The beneficial effects of the present invention are as follows: It provides a zero-point detection method and apparatus for distance detection. By accumulating and averaging the counting results of time boxes within a specified range, the amount of data processing required to calculate the zero-point distance is small. It does not require the calculation of a complete histogram and peak finding, which effectively saves the storage space and hardware resources occupied by zero-point detection and reduces the detection cost. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0037] Figure 1 This is an application environment diagram of the zero-point detection method for distance detection in an embodiment of the present invention;

[0038] Figure 2 This is a flowchart of the zero-point detection method for distance detection in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of a zero-point detection structure in an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of another zero-point detection structure in an embodiment of the present invention;

[0041] Figure 5 This is a schematic diagram of TDC data statistics in an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram illustrating a specified range under different scenarios in embodiments of the present invention;

[0043] Figure 7 This is a schematic diagram of weight encoding in an embodiment of the present invention;

[0044] Figure 8 This is a structural diagram of the zero-point detection device for distance detection in an embodiment of the present invention. Detailed Implementation

[0045] To make the technical problems, technical solutions, and beneficial effects of the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0046] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be for both fixing and circuit connection purposes.

[0047] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0048] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] The zero-point detection method for distance detection provided in this embodiment of the invention can be applied to, for example... Figure 1The time-of-flight distance detector shown includes a lens 10, a control unit 11, a transmitting unit 12, and a receiving unit 13. The transmitting unit 12 includes a driver 121 and a light source 122, and the receiving unit 13 includes a pixel unit 131 and a lens 132. The control unit 11 is connected to both the transmitting unit 12 and the receiving unit 13, and is used to synchronously control the emission and reception of light, calculate the distance information corresponding to the time difference between the emission and reception of light, and dynamically control the switching area of ​​the pixel unit 131. The control unit 11 controls the transmitting unit 12, which drives the light source 122 to emit a light beam 20 through the driver 121. The light beam 20 is projected onto the target object 60 through the lens 10 to generate a reflected light beam 30, which is received by the receiving unit 13, thus realizing time-of-flight distance detection.

[0050] In distance detection, there is a time difference between the output time of the control signal controlling laser emission and the actual laser emission time. Therefore, zero-point detection is needed to account for this time difference. This allows the distance measured by subtracting the zero-point distance from the distance reflected back from the target object to obtain the actual distance to the target object. Currently, a complete histogram analysis of the laser at the emission end is typically performed to find the peak and determine the zero-point location. This method of histogram analysis of the zero point requires significant storage space and has a complex hardware structure, increasing detection costs. Therefore, the following describes a zero-point detection method applied to distance detectors to address this problem, saving storage space and hardware resources required for zero-point detection and reducing detection costs.

[0051] like Figure 2 As shown, Figure 2 This is a flowchart of a zero-point detection method for distance detection in one embodiment of the present invention. The method specifically includes the following steps:

[0052] S201, the TOF chip continuously sends control signals to the drive module. When the drive module emits drive signals to the laser according to the control signals, the TOF chip synchronously receives the zero-point electrical signal.

[0053] In this embodiment, combined with, as Figure 3 The diagram shows a zero-point detection structure. The control module (TRGU module) in the TOF chip continuously sends control signals to the driver module (DRV module) of the VCSEL laser through the IO interface. The driver module then sends a drive signal to the laser to start emitting laser light. At the same time, the TOF chip synchronously receives the zero-point electrical signal. Since there is a time difference between the TRGU module sending the control signal and the TOF chip receiving the zero-point electrical signal, which corresponds to a very close zero-point distance, the distance measured by the real object must be subtracted from this zero-point distance. Therefore, the zero-point distance needs to be detected based on the received zero-point electrical signal to improve the accuracy of distance measurement.

[0054] In one embodiment, the zero-point electrical signal is specifically the driving signal that the TOF chip synchronously receives as the zero-point electrical signal when the driving module emits a driving signal to the laser. For example... Figure 3 As shown, the drive module, triggered by the control signal, begins to emit a drive signal to the laser. Simultaneously, it loops back a drive signal to the TOF chip's I / O interface, which is then fed into the TOF chip's TDC module (ZDD TDC module) for time-distance counting. This looped-back drive signal is used as the zero-point electrical signal. This signal loopback operation enables synchronous reception of the zero-point electrical signal without the need for additional hardware, reducing the cost of detection hardware.

[0055] In one embodiment, the zero-point electrical signal specifically refers to the signal received by the reference SPAD array of the TOF chip when the laser begins to emit laser light, and converted into a zero-point electrical signal. For example... Figure 4 As shown, the zero-point electrical signal can also be realized through optical signal detection. When the laser receives the driving signal and begins to emit laser light, the laser is detected by the reference SPAD array of the TOF chip, or by other photodetectors such as PD (Photo-Diode) or APD (Avalanche Photo-Diode), and the detected optical signal is converted into a zero-point electrical signal and input to the IO interface of the TOF chip. Preferably, the output signal of the photodetector can also be amplified by a TIA (Transimpedance Amplifier) ​​before being input to the IO interface of the TOF chip as a zero-point electrical signal, which facilitates subsequent signal processing and measurement and improves the accuracy of zero-point detection.

[0056] S202, the TOF chip performs TDC conversion on each received zero-point electrical signal and counts on the corresponding time bin based on the converted TDC data.

[0057] As control signals are continuously emitted, the TOF chip continuously receives zero-point electrical signals synchronously. It performs a time-to-digital (TDC) conversion on the received zero-point electrical signals to obtain the corresponding TDC data, which represents the time interval between the signal's emission from the control module and its reception by the TDC module. Based on this TDC data, counts are performed in the corresponding time bins (storage units for storing time information), serving as the data foundation for accurately detecting the zero-point distance.

[0058] The S203 and TOF chips accumulate and average the values ​​of each time box within a specified range to obtain the average value of the time boxes.

[0059] S204 The TOF chip calculates the zero-point distance based on the average value of the time bins.

[0060] After recording the time bin values ​​and corresponding count results for the zero-point electrical signal, the time bin values ​​are accumulated and averaged based on the count results of each time bin within a specified range to obtain the average value of the time bins, and then the zero-point distance is calculated. Specifically, the specified range is the range of time bins corresponding to a preset zero-point distance range. Since the zero-point distance is usually very small, the range of time bins corresponding to the preset zero-point distance range is also very small, which greatly reduces the amount of data processed during zero-point detection and improves detection efficiency.

[0061] In this embodiment, the counting results of each time bin can be used as the weight of the corresponding time bin during data statistics, representing the frequency of each time bin value when averaging. This ensures that the average value obtained after averaging will approach the time bin value with the most triggers, i.e., the peak value in the corresponding histogram statistics. Therefore, this embodiment does not need to perform complete histogram statistics and peak finding processing on the zero-point signal as in existing solutions to obtain the zero-point distance. Instead, it pre-sets a small specified range, and obtains the average value of the time bins by averaging the time bin values ​​within the specified range based on the recorded time bin values ​​and the number of accumulations, and then calculates the zero-point distance. This reduces the amount of data processing and can greatly save storage space and hardware resources, effectively reducing the cost of zero-point detection.

[0062] In one embodiment, step S203 includes:

[0063] Read the value of the corresponding time bin for each count based on TDC data;

[0064] Confirm whether the value of the time box belongs to the specified range. If it does, accumulate the value of the time box. If it does not belong, filter out the value of the time box until the accumulation ends.

[0065] The average value of the time bins is obtained by averaging the accumulated results based on the number of accumulations.

[0066] In this embodiment, combined with, as Figure 5The diagram illustrates TDC data statistics. When accumulating and averaging time bin values, each time TDC data is counted based on the transformation, the value of the corresponding time bin is read. Then, it is determined whether the value of the currently counted time bin is between the specified range MIN_BIN and MAX_BIN. If it is, the time bin value of the currently counted TDC data is accumulated; otherwise, the time bin value corresponding to that TDC data is filtered out. This process continues until the accumulation is complete. The accumulated result is averaged based on the number of accumulations. This number of accumulations is the sum of the count values ​​of all time bins within the specified range. The average value of the time bins is obtained through this averaging method and serves as the bin value corresponding to the peak value of the histogram. Figure 6 As shown, different MIN_BIN and MAX_BIN can be set for different ranging histogram scenarios to adapt to scene changes. This allows for efficient and accurate acquisition of the time distance corresponding to the peak without constructing a complete zero-point detection histogram, greatly saving storage space while accurately achieving zero-point detection.

[0067] For example, if the specified range is time bin126 to time bin130, if the time bin value after the zero-point electrical signal conversion is 126, then accumulate 126; if the time bin value after the zero-point electrical signal conversion is 128, then accumulate 128; if the time bin value after the zero-point electrical signal conversion is 120, then filter it directly, and so on, until the accumulation ends, and the accumulated result is (C a ×126+C b ×127+C c ×128+C d ×129+C e ×130), where C a C is the count value of bin126. d C is the count value of bin127. d C is the count value of bin128. d C is the count value of bin129. e The count value of bin130 is used to calculate the average value of the time bin:

[0068] AVG = (C a ×126+C b ×127+C c ×128+C d ×129+C e ×130) / (C a +C b +C c +C d +C e )

[0069] In the above cumulative averaging process, the count value of each bin value at each time point is used as the weight for weighted averaging, such that if the count value of bin128 is the largest, i.e., C... c If the value of is maximized, the value of AVG will be closer to 128. Thus, even with a small amount of data, the time bin value corresponding to the zero point distance can be found, effectively saving storage space and hardware resources occupied by zero point detection.

[0070] In one embodiment, prior to step S203, the method further includes:

[0071] Weighted encoding is performed on the values ​​of each time bin within a specified range to obtain the encoded value of each time bin.

[0072] In this embodiment, in order to further reduce the bit width of the accumulator and thus reduce hardware resources, the values ​​of each time bin within a specified range are first weighted and encoded before the accumulation and averaging process is performed to obtain the encoded value of each time bin. The encoded value is smaller than the data volume of the time bin value, thereby compressing the data of all time bin values ​​participating in the accumulation and averaging process and further saving storage space.

[0073] Furthermore, the accumulation of the values ​​in the time bins specifically refers to:

[0074] The encoded values ​​corresponding to the values ​​of the time bins are accumulated to obtain the accumulated encoded value of the time bins.

[0075] In this embodiment, instead of directly accumulating the time bin values ​​based on the counting results, the encoded values ​​corresponding to the time bin values ​​are accumulated. This results in the encoded accumulated value being much smaller than the result of directly accumulating the time bin values, effectively reducing the bit width of the accumulator and saving hardware resources and detection costs.

[0076] Furthermore, the step of averaging the accumulated results based on the number of accumulations to obtain the average value of the time bins includes:

[0077] The average encoded value of the time bin is obtained by averaging the accumulated values ​​based on the number of accumulations.

[0078] The average encoded value is decoded to obtain the average value of the time bins.

[0079] In this embodiment, based on the summation of the encoded values ​​according to the counting results of each time box, the average value is calculated by averaging the summation values ​​according to the number of summations. After obtaining the average encoded value of the time box, the decoding process is performed in the reverse of the encoding process. The average value of the time box can still be obtained. This minimizes hardware resources and does not affect the accuracy of the zero-point distance obtained by the summation and averaging process.

[0080] In one embodiment, the weighted encoding of the values ​​of each time bin within a specified range to obtain the encoded value of each time bin includes:

[0081] Determine the reference time box within the specified range;

[0082] The value of each time box is subtracted from the value of the reference time box to obtain the encoded value of each time box.

[0083] In this embodiment, encoding can be performed using a reference time box. Since the distance between the driver chip and the SPAD of the TOF chip is fixed, a reference time box can be predicted and set in advance. The value of each time box within the specified range is subtracted from the value of the reference time box, and the difference is used as the encoding value of each time box, thereby greatly reducing the accumulation result.

[0084] like Figure 7 As shown, the specified range is from time bin126 to time bin130, with time bin values ​​of 126, 127, 128, 129, and 130, respectively, and the corresponding count value is C. a C b C c C d C e If the time bin values ​​are directly summed, the mean of the final sum is:

[0085] AVG = (C a ×126+C b ×127+C c ×128+C d ×129+C e ×130) / (C a +C b +C c +C d +C e )

[0086] At this point, the accumulated value will be quite large. If bin128 is used as the base time bin to encode the values ​​of each time bin, the corresponding encoded values ​​are -2, -1, 0, 1, and 2, respectively. t The principle for averaging the encoded data is as follows:

[0087] AVG = (C a ×(128-2)+C b ×(128-1)+C c ×128+C d ×(128+1)+C e ×(128+2)) / (C a +C b +C c +Cd +C e )

[0088] After simplification, we get:

[0089] AVG = 128 + (C a ×(-2)+C b ×(-1)+C c ×0+C d ×(1)+C e ×(2)) / (C a +C b +C c +C d +C e )

[0090] When accumulating the counts from each time bin, if the bin to be accumulated is 126, then -2 is added; similarly, if the bin is 127, then -1 is added; if the bin is 128, then 0 is added; if the bin is 129, then 1 is added; and if the bin is 130, then 2 is added. The final accumulated value is much smaller than the value of the bin directly accumulated. By averaging the accumulated encoded values ​​and adding the base value of 128, the same average value as the value of the bin directly accumulated can be obtained, which greatly reduces the bit width of the accumulator and saves hardware resources for zero-point detection to the greatest extent.

[0091] It should be noted that there is no necessary order between the above steps. Those skilled in the art will understand from the description of the embodiments of the present invention that the above steps may have different execution orders in different embodiments, that is, they may be executed in parallel or in turn, etc.

[0092] The present invention also provides a zero-point detection device for distance detection, such as... Figure 8 As shown, Figure 8The diagram illustrates the structure of a zero-point detection device for distance detection in one embodiment of the invention. It includes a control module 801, a TDC module 802, and a data processing module 803, which are sequentially connected. The control module 801 continuously sends control signals to a drive module. When the drive module emits a drive signal to the laser according to the control signals, it simultaneously receives the zero-point electrical signal. The TDC module 802 performs TDC conversion on each received zero-point electrical signal and counts the data in the corresponding time bins based on the converted TDC data. The data processing module 803 accumulates and averages the values ​​of each time bin within a specified range to obtain the average value of the time bins. It then calculates the zero-point distance based on the average value of the time bins. Since the zero-point detection process for distance detection has been described in detail in the above method embodiments, please refer to the corresponding method embodiments above for further details; further elaboration is not provided here.

[0093] In summary, this invention provides a zero-point detection method and apparatus for distance detection. The method includes: a Time-of-Flight (TOF) chip continuously sending control signals to a driving module; when the driving module emits driving signals to a laser according to the control signals, the TOF chip synchronously receives a zero-point electrical signal; the TOF chip performs Time-of-Conversion (TDC) conversion on each received zero-point electrical signal and counts the values ​​in corresponding time bins based on the converted TDC data; the TOF chip accumulates and averages the count results of each time bin within a specified range to obtain an average value for the time bins; and the TOF chip calculates the zero-point distance based on the average value of the time bins. By accumulating and averaging the count results of the time bins within a specified range, the data processing volume for calculating the zero-point distance is reduced, eliminating the need for calculating a complete histogram and peak finding, effectively saving storage space and hardware resources occupied by zero-point detection, and reducing detection costs.

[0094] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, achieving the same performance or purpose, should be considered within the scope of protection of the present invention.

Claims

1. A zero-point detection method for distance detection, characterized in that, The steps include the following: The TOF chip continuously sends control signals to the driving module. When the driving module emits a driving signal to the laser according to the control signal, the TOF chip synchronously receives the zero-point electrical signal. Specifically, the zero-point electrical signal is either received by the TOF chip as a zero-point electrical signal when the driving module emits a driving signal to the laser, or received by the reference SPAD array of the TOF chip when the laser starts emitting laser light and converted into a zero-point electrical signal. The TOF chip performs TDC conversion on each received zero-point electrical signal and counts the data in the corresponding time bin based on the converted TDC data. The TOF chip accumulates and averages the values ​​of each time box based on the counting results of each time box within a specified range to obtain the average value of the time boxes; the specified range is specifically the range of time boxes corresponding to a preset zero-point distance range; The TOF chip calculates the zero-point distance based on the average value of the time bins; Before averaging the values ​​of each timebox based on the count results within a specified range to obtain the average value of the timeboxes, the method further includes: The values ​​of each time bin within a specified range are weighted and encoded to obtain the encoded value of each time bin. Specifically, the weighting encoding involves compressing the data of all time bin values ​​participating in the cumulative averaging process to obtain an encoded value with a smaller data volume than the time bin value data.

2. The zero-point detection method for distance detection according to claim 1, characterized in that, The step of averaging the counts of each timebox within a specified range to obtain the average value of the timeboxes includes: Read the value of the corresponding time bin for each count based on TDC data; Confirm whether the value of the timebox belongs to the specified range. If it does, accumulate the value of the timebox. If it does not belong, filter out the value of the timebox until the accumulation ends. The average value of the time bins is obtained by averaging the accumulated results based on the number of accumulations.

3. The zero-point detection method for distance detection according to claim 2, characterized in that, The accumulation of the values ​​in the time bins specifically refers to: The encoded values ​​corresponding to the values ​​of the time bins are accumulated to obtain the accumulated encoded value of the time bins.

4. The zero-point detection method for distance detection according to claim 3, characterized in that, The step of averaging the accumulated results based on the number of accumulations to obtain the average value of the time bins includes: The average encoded value of the time bin is obtained by averaging the accumulated values ​​based on the number of accumulations. The average encoded value is decoded to obtain the average value of the time bins.

5. The zero-point detection method for distance detection according to claim 2, characterized in that, The step of weighting and encoding the values ​​of each time bin within a specified range to obtain the encoded value of each time bin includes: Determine the reference time box within the specified range; The value of each time box is subtracted from the value of the reference time box to obtain the encoded value of each time box.

6. A zero-point detection device for distance detection, characterized in that, include: The control module continuously sends control signals to the drive module. When the drive module emits a drive signal to the laser according to the control signal, it synchronously receives a zero-point electrical signal. Specifically, the zero-point electrical signal is either received by the TOF chip as a zero-point electrical signal when the drive module emits a drive signal to the laser, or received by the reference SPAD array of the TOF chip as a zero-point electrical signal when the laser starts emitting laser light. The TDC module is used to perform TDC conversion on each received zero-point electrical signal and count the data in the corresponding time bin based on the converted TDC data. The data processing module is used to accumulate and average the values ​​of each time box based on the counting results of each time box within a specified range to obtain the average value of the time boxes. The specified range is specifically the range of time boxes corresponding to a preset zero-point distance range. The module also calculates the zero-point distance based on the average value of the time boxes. Furthermore, the module performs weighted encoding on the values ​​of each time box within the specified range to obtain the encoded value of each time box. Specifically, the weighted encoding involves compressing the data of all time box values ​​participating in the accumulation and averaging process to obtain an encoded value with a smaller data volume than the time box value.

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