A method for improving ranging accuracy, a rangefinder, a storage medium, and a lidar

Abstract

The present invention relates to the field of lidar, and particularly to a method for improving ranging accuracy, a range finder, a storage medium, and a lidar. The method specifically includes: presetting a sequence table and a correction table; sampling at a first rate to obtain a current sampling sequence and calculating a current distance value; obtaining a current phase according to the current sampling sequence and the sequence table, and obtaining a current error value according to the current phase and the correction table; obtaining an actual distance value according to the current distance value and the current error value. By setting a sequence table that can reflect the corresponding relationship between "sampling sequence - phase" and a correction table that can reflect the corresponding relationship between "phase - error value", the present invention makes different sampling sequences correspond one by one to different phases and different ranging deviation values. After the lidar collects the sampling sequence of the echo signal, only by referring to the sequence table and the correction table can the actual detection distance of the current sampling sequence be obtained, without restoring the original waveform of the echo signal, greatly reducing the computational complexity.

Description

Technical Field

[0001] The present invention relates to the field of lidar, and particularly to a method for improving ranging accuracy, a rangefinder, a storage medium, and a lidar. Background Art

[0002] The main method for calculating the flight time of a laser pulse is to use the laser emission moment as the starting moment. After the received laser pulse signal is subjected to optoelectronic conversion, the waveform information of the echo signal is collected by an ADC (analog-to-digital conversion) chip, and then the moment information of the laser pulse return is obtained through digital signal processing methods, so as to obtain the laser pulse flight time △T according to the ADC sampling clock information. In order to reduce costs and power consumption, in actual applications, an ADC chip with a relatively low rate (~1GSPS) is often used. The collected waveform is a discrete waveform, and a complex high-order interpolation algorithm needs to be used to restore the original continuous waveform of the pulse signal to improve ranging accuracy, and its calculation amount is very large.

[0003] Therefore, it is crucial for this field to design a method for improving ranging accuracy, a rangefinder, a storage medium, and a lidar that can reduce the calculation amount and have high measurement result accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for improving ranging accuracy, a rangefinder, a storage medium, and a lidar in view of the above-mentioned defects of the prior art, and to overcome the defects such as low measurement result accuracy and large calculation amount in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is: to provide a method for improving ranging accuracy. Preferably, the method for improving ranging accuracy is applied to a lidar system, and specifically includes the following steps:

[0006] Preset a sequence table to reflect the correspondence between the phase and the sampling sequence;

[0007] Preset a correction table to reflect the correspondence between the phase and the error value;

[0008] Sample at a first rate to obtain the current sampling sequence, and calculate the current distance value;

[0009] Obtain the current phase according to the current sampling sequence and the sequence table, and obtain the current error value according to the current phase and the correction table;

[0010] Obtain the actual distance value according to the current distance value and the current error value.

[0011] Among them, in a preferred solution, the calculation of the current distance value specifically includes the following steps:

[0012] Obtain the acquisition moment of the current sampling sequence;

[0013] Calculate the time difference between the acquisition time of the current sampling sequence and the corresponding transmission time to obtain the time of flight.

[0014] Calculate the current distance value through the time of flight and the speed of light.

[0015] Among them, the preferred solution is that the preset sequence list includes the following steps:

[0016] Sample at the second rate and obtain the reference signal.

[0017] Downsample the reference signal with different phases to obtain multiple sampling sequences.

[0018] Correspond the phase with the sampling sequence one by one to form a sequence list.

[0019] Among them, the preferred solution is that the second rate is higher than the first rate.

[0020] Among them, the preferred solution is that the preset correction table includes the following steps:

[0021] Calculate the reference distance value according to the reference signal.

[0022] Calculate multiple corresponding target distance values according to multiple sampling sequences.

[0023] Compare multiple target distance values with the reference distance value respectively to obtain multiple error values corresponding to the sampling sequences.

[0024] Correspond the error value with the phase one by one according to the sequence list to form a correction table.

[0025] Among them, the preferred solution is that the calculation of the reference distance value specifically includes the following steps:

[0026] Obtain the acquisition time of the reference signal.

[0027] Calculate the time difference between the acquisition time of the reference signal and the corresponding transmission time to obtain the time of flight.

[0028] Calculate the reference distance value through the time of flight and the speed of light.

[0029] Among them, the preferred solution is that the calculation of the target distance value specifically includes the following steps:

[0030] Obtain the acquisition times of multiple sampling sequences respectively.

[0031] Calculate the time difference between the acquisition time of the sampling sequence and the corresponding transmission time to obtain the time of flight.

[0032] Calculate the target distance value through the time of flight and the speed of light.

[0033] To solve the problems existing in the prior art, the present invention further provides a lidar, and its preferred solution lies in that: the lidar is used to implement the method as described above, and includes a laser unit, a scanning unit, and a signal processing unit. The signal processing unit includes a photoelectric conversion module and an ADC sampling module. The laser unit is connected to the scanning unit, the scanning unit is connected to the photoelectric conversion module, the photoelectric conversion module is connected to the ADC sampling module, and the ADC sampling module is connected to the laser unit.

[0034] To solve the problems existing in the prior art, the present invention further provides a rangefinder, and its preferred solution lies in that: it includes a storage unit and a processing unit. The storage unit stores a computer program. When the computer program is executed by the processing unit, the processing unit executes the steps of the method as described above.

[0035] To solve the problems existing in the prior art, the present invention further provides a storage medium, and its preferred solution lies in that: it stores a computer program. When the computer program is executed by a processor, the processor executes the steps of the method as described above.

[0036] The beneficial effect of the present invention is that, compared with the prior art, the present invention realizes high-precision ranging of the lidar by designing a method, a rangefinder, a storage medium, and a lidar for improving ranging accuracy; by setting a sequence table that can reflect the correspondence between "sampling sequence - phase" and a correction table that can reflect the correspondence between "phase - error value", different sampling sequences are made to correspond one by one with different phases and different ranging deviation values. When the lidar collects the sampling sequence of the echo signal, only by referring to the sequence table and the correction table can the actual detection distance of the current sampling sequence be obtained, without restoring the original waveform of the echo signal, which greatly reduces the computational complexity. Description of the Drawings

[0037] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0038] Figure 1 is a flowchart of a method for improving ranging accuracy in the present invention;

[0039] Figure 2 is a flowchart of a current distance calculation method in the present invention;

[0040] Figure 3 is a flowchart of a method for presetting a sequence table in the present invention;

[0041] Figure 4 is a flowchart of a method for presetting a correction table in the present invention;

[0042] Figure 5It is a flowchart of a method for calculating a reference distance value in the present invention;

[0043] Figure 6 It is a flowchart of a method for calculating a target distance value in the present invention;

[0044] Figure 7 It is a schematic structural diagram of a lidar in the present invention;

[0045] Figure 8 It is a schematic structural diagram of a rangefinder in the present invention;

[0046] Figure 9 It is a schematic structural diagram of a storage medium in the present invention. Specific Embodiments

[0047] Now, in conjunction with the accompanying drawings, detailed descriptions of the preferred embodiments of the present invention will be given.

[0048] As Figure 1 shown, the present invention provides a preferred embodiment of a method for improving ranging accuracy.

[0049] A method for improving ranging accuracy, referring to Figure 1 , the method for improving ranging accuracy is applied to a lidar system, and specifically includes the following steps:

[0050] S1. Preset a sequence table to reflect the correspondence between phases and sampling sequences;

[0051] S2. Preset a correction table to reflect the correspondence between phases and error values;

[0052] S3. Sample at a first rate to obtain a current sampling sequence and calculate a current distance value;

[0053] S4. Obtain a current phase according to the current sampling sequence and the sequence table, and obtain a current error value according to the current phase and the correction table;

[0054] S5. Obtain an actual distance value according to the current distance value and the current error value.

[0055] Specifically, during the ranging process of lidar, an ADC chip is generally used to sample the echo pulse signal. The higher the sampling rate of the ADC chip, the more continuous the waveform of the echo pulse it collects, and the higher the calculated distance accuracy. However, due to the very high cost and power consumption of high-speed ADC chips. Considering cost, the ADC chips used in lidar systems are often rate-limited, and generally low-rate (e.g., 1Gsps) ADC chips are used. The low-rate ADC chips cannot collect all the signals of the echo pulse, causing the original continuous waveform to be sampled as a discrete waveform, and there are also large errors in the calculated measurement distance, which cannot meet the application requirements. It is necessary to perform some processing on the sampled signal to improve the distance measurement accuracy.

[0056] In this embodiment, using the principle that "the same pulse signal will present different signal forms due to different ADC sampling phases, and different distance measurement errors will also be introduced due to different signal forms", a pulse matching method is designed, that is, a series of correspondence tables are preset to reflect the one-to-one correspondence between the phase and the sampling sequence and between the phase and the measurement error value. In this way, it is only necessary to know the sampling sequence currently collected by the ADC chip to obtain the corresponding phase information, and then the measurement error value corresponding to it can be obtained through the phase information. Finally, the current measurement value is calculated from the current sampling sequence, and the current measurement value and the measurement error value are combined to obtain the actual measurement distance of the current sampling sequence.

[0057] Specifically, a sequence table is preset first. The sequence table is mainly used to reflect the one-to-one correspondence between the phase and the sampling sequence. The sequence table includes multiple phases and multiple sampling sequences corresponding to the phases. The sampling sequence refers to different discrete waveforms of the original echo signal corresponding to different phases. By comparing the sampling sequence with the waveform of the original echo signal, the sampling phase corresponding to the sampling sequence can be obtained. In this embodiment, each sampling sequence is corresponded to each phase information one by one to form a preset sequence table. When the ADC chip collects the current sampling sequence, it can directly compare the current sampling sequence with multiple sampling sequences in the sequence table to find the corresponding phase information, without restoring the original waveform of the echo signal, greatly reducing the calculation amount.

[0058] Furthermore, a correction table is preset. The correction table is mainly used to reflect the correspondence between the phase and the error value. The correction table includes multiple phases and multiple error values corresponding to the phases one by one. When the phase of the current sampling sequence is obtained, the corresponding error value can be directly found according to the correction table. By adding the current measurement distance value and the error value, the actual distance value of the current measurement target can be obtained.

[0059] Among them, by using this method to process the current sampling sequence, it is not necessary to effectively restore the original form of the signal from the currently collected sampling sequence through a high-order interpolation algorithm. While improving the ranging accuracy, the computational amount is also greatly reduced.

[0060] As Figure 2 shown, the present invention provides an optimal embodiment of a current distance calculation method.

[0061] Referring to Figure 2 , the specific steps for calculating the current distance value include the following:

[0062] S31. Obtain the acquisition time of the current sampling sequence;

[0063] S32. Calculate the time difference between the acquisition time of the current sampling sequence and the corresponding emission time to obtain the flight time;

[0064] S33. Calculate the current distance value through the flight time and the speed of light.

[0065] Specifically, when the lidar emits one or more laser pulse signals, after the pulse signal irradiates the target object, a part of the energy will be reflected correspondingly. This part of the reflected energy can be received by the detection system of the lidar. The detection system can obtain the flight time of the laser pulse by calculating the time difference between the emission time and the reception time of the pulse signal, and then calculate the distance of the target object according to the propagation speed of light in the air.

[0066] Among them, the corresponding emission time specifically refers to the time when the laser emits the laser pulse, that is, the starting moment of the emission of the laser pulse. By calculating the time difference between the acquisition time of the current sampling sequence and the corresponding pulse emission time, the flight time of the pulse can be obtained, thereby calculating the distance of the target object that reflects the pulse to achieve the distance detection of the currently detected target object; specifically, digital signal processing can be performed through an ADC chip, that is, converting the waveform information of the sampled echo signal into digital time information, and then sampling the starting moment of the emission of the laser pulse through the sampling clock information of the ADC chip, and comparing and calculating the time information of the current sampling sequence with the starting moment of the emission of the laser pulse to obtain the flight time of the laser pulse.

[0067] As Figure 3 shown, the present invention provides an optimal embodiment of a preset sequence list method.

[0068] Referring to Figure 3 , the preset sequence list includes the following steps:

[0069] S11. Sample at the second rate and obtain a reference signal;

[0070] S12. Downsample the reference signal with different phases to obtain multiple sampling sequences;

[0071] S13. Correlate the phases with the sampling sequences one by one to form a sequence table.

[0072] Specifically, the reference information is actually a reference sampling waveform obtained by sampling at a second rate. Wherein, the second rate is higher than the first rate, specifically N times the first rate. That is to say, the reference information obtained by sampling at the second rate can be regarded as the superposition of N sampling sequences obtained by sampling N times at the first rate. That is to say, the sampling sequence obtained by sampling at the first rate is actually the sampling waveform of the reference information sampled at the second rate at a certain phase. By downsampling the reference information with different phases, multiple different sampling sequences can be obtained, and the multiple sampling sequences correspond to multiple phases one by one. By listing the corresponding relationship between the multiple phases and the multiple sampling sequences in the form of a corresponding table, a "sampling sequence - phase" corresponding table, that is, the sequence table, can be obtained.

[0073] As Figure 4 shown, the present invention provides a best embodiment of a method for presetting a correction table.

[0074] Reference Figure 4 , the method for presetting the correction table includes the following steps:

[0075] S21. Calculate a reference distance value according to the reference signal;

[0076] S22. Calculate multiple corresponding target distance values according to the multiple sampling sequences;

[0077] S23. Compare the multiple target distance values with the reference distance value respectively to obtain multiple error values corresponding to the sampling sequences;

[0078] S24. Correlate the error values with the phases one by one according to the sequence table to form a correction table.

[0079] Specifically, according to the reference signal obtained by sampling at the second rate, the reference distance value corresponding to the target is calculated. Since the second rate is N times the first rate, the accuracy of the sampled reference signal is very high, and thus the accuracy of the calculated reference distance value is also very high, being infinitely close to the actual distance value. By using the reference signal and the reference distance value as the comparison reference data for the actual ranging data, the ranging accuracy can be effectively improved. Since the same pulse signal will obtain different sampling sequences at different sampling phases, the differences in such sampling sequences will introduce different ranging errors. By performing digital signal processing on the different sampling sequences collected at different phases, multiple corresponding target distance values with certain ranging errors are obtained. By comparing each of the multiple target distance values with the reference distance value, multiple error values can be obtained, and the error values correspond one-to-one with the sampling sequences and also correspond one-to-one with the phases. By listing the corresponding relationships between the multiple phases and the multiple error values in the form of a corresponding table, a "phase-error value" corresponding table, i.e., the correction table, can be obtained.

[0080] As Figure 5 shown, the present invention provides a best embodiment of a method for calculating a reference distance value.

[0081] Reference Figure 5 , the specific calculation of the reference distance value includes the following steps:

[0082] S211. Obtain the acquisition time of the reference signal;

[0083] S212. Calculate the time difference between the acquisition time of the reference signal and the corresponding emission time to obtain the flight time;

[0084] S213. Calculate the reference distance value through the flight time and the speed of light.

[0085] Specifically, when the lidar emits one or more laser pulse signals, after the pulse signal irradiates the target, a part of the energy will be reflected correspondingly, and this part of the reflected energy can be received by the detection system of the lidar. The detection system can obtain the flight time of the laser pulse by calculating the time difference between the emission time and the reception time of the pulse signal, and then calculate the distance of the target according to the propagation speed of light in the air.

[0086] Among them, the corresponding emission time specifically refers to the time when the laser emits the laser pulse, that is, the starting moment of the emission of the laser pulse. By calculating the time difference between the acquisition time of the reference signal and the corresponding pulse emission time, the flight time of the pulse can be obtained, and then the distance of the target reflecting the pulse can be calculated to achieve the distance detection of the currently detected target. Specifically, digital signal processing can be performed through an ADC chip, that is, converting the reference signal of the sampled echo signal into digital time information, sampling the starting moment of the emission of the laser pulse through the sampling clock information of the ADC chip, and comparing and calculating the time information of the reference signal with the starting moment of the emission of the laser pulse to obtain the flight time of the laser pulse.

[0087] As Figure 6 shown, the present invention provides a best embodiment of a method for calculating a target distance value.

[0088] Referring Figure 6 , the specific calculation of the target distance value includes the following steps:

[0089] S221. Respectively obtain the acquisition times of multiple sampling sequences;

[0090] S222. Calculate the time difference between the acquisition time of the sampling sequence and the corresponding emission time to obtain the flight time;

[0091] S223. Calculate the target distance value through the flight time and the speed of light.

[0092] Specifically, when a lidar emits one or more laser pulse signals, after the pulse signal irradiates the target, a part of the reflected energy will be correspondingly reflected, and this part of the reflected energy can be received by the detection system of the lidar. The detection system can obtain the flight time of the laser pulse by calculating the time difference between the emission time and the reception time of the pulse signal, and then calculate the distance of the target according to the propagation speed of light in the air.

[0093] Among them, the corresponding emission time specifically refers to the time when the laser emits the laser pulse, that is, the starting moment of the emission of the laser pulse. By calculating the time difference between the acquisition times of multiple sampling sequences under different phases and the corresponding pulse emission time, the flight time of the pulse can be obtained, and then the distance of the target reflecting the pulse can be calculated to achieve the distance detection of the target. Specifically, digital signal processing can be performed through an ADC chip, that is, converting multiple sampling sequences under different phases sampled into digital time information, sampling the starting moment of the emission of the laser pulse through the sampling clock information of the ADC chip, and comparing and calculating the time information of the reference signal with the starting moment of the emission of the laser pulse to obtain multiple flight times of different phase samplings.

[0094] As shown Figure 7 in the figure, the present invention provides an optimal embodiment of a lidar.

[0095] A lidar, referring to Figure 7 , the lidar is used to implement the method as described above, and includes a laser unit 1, a scanning unit 2, and a signal processing unit 3. The signal processing unit 3 includes a photoelectric conversion module 31 and an ADC sampling module 32. The laser unit 1 is connected to the scanning unit 2, the scanning unit 2 is connected to the photoelectric conversion module 31, the photoelectric conversion module 31 is connected to the ADC sampling module 32, and the ADC sampling module 32 is connected to the laser unit 1.

[0096] Specifically, the laser unit 1 is mainly used to emit detection laser. The scanning unit 2 is a 2D scanner, and its scanning method can be mechanical scanning, MEMS scanning, OPA scanning, etc. The laser unit 1 emits detection laser, and the detection laser is continuously scanned by the scanning unit 2. When the laser pulse irradiates the target object, a part of the light energy is reflected back to the signal processing unit 3 in the lidar. The signal processing unit 3 collects the echo signal and performs digital processing on the echo signal to obtain the acquisition time of the echo signal and the pulse emission time, so as to obtain the flight time of the detection signal, and thus obtain the distance of the target object.

[0097] Furthermore, referring to Figure 7 , the signal processing unit 3 includes a photoelectric conversion module 31, an ADC sampling module 32, and a control module. The photoelectric conversion module 31 and the ADC sampling module 32 are both connected to the control module. The photoelectric conversion module 31 is arranged between the scanning unit 2 and the ADC sampling module 32, and is mainly used to convert the optical signal into an electrical signal. Specifically, the photoelectric conversion module 31 can convert the echo signal reflected by the target object into an electrical signal and send it to the ADC sampling module 32. The ADC sampling module 32 is specifically an analog-to-digital converter, and the ADC sampling module 32 is mainly used for signal acquisition and digital processing of the signal. The electrical signal converted by the photoelectric converter is input to the ADC chip, and digital signal processing is performed through the ADC chip, that is, the sampled echo signal is converted into digital time information, and the starting time of the laser pulse emission sampled by the ADC chip sampling clock information can also be obtained, and the time information when the echo signal is collected is compared and calculated with the starting time of the detection laser pulse emission, so as to obtain the flight time of the laser pulse. Finally, the distance of the target object can be obtained according to the propagation speed of light in the air.

[0098] Furthermore, referring to Figure 7, the lidar further includes a transmitting collimator 4 disposed between the laser unit 1 and the scanning unit 2 and a receiving focusing mirror 5 disposed between the scanning unit 2 and the photoelectric conversion module 31. The transmitting collimator 4 is mainly used to collimate the detection laser emitted by the laser unit 1, and the receiving focusing mirror 5 is mainly used to converge a part of the detection signals reflected by the target object.

[0099] Wherein, the above method for improving ranging accuracy is implemented by the lidar, and the specific algorithms involved in the method are implemented by the signal processing module.

[0100] As Figure 8 shown, the present invention provides a best embodiment of a rangefinder.

[0101] A rangefinder 6, referring to Figure 8 , the rangefinder 6 includes a storage unit 61 and a processing unit 62. The storage unit 61 stores a computer program. When the computer program is executed by the processing unit 62, the processing unit 62 is caused to execute the steps of the method as described above.

[0102] Specifically, the rangefinder 6 includes a storage unit 61 and a processing unit 62. The storage unit 61 is coupled to the processing unit 62. The processing unit 62 stores a computer program. When the processing unit 62 is operating, it executes the computer program to implement the method as Figure 1 shown. For the detailed method, reference can be made to the above, and details will not be elaborated here.

[0103] As Figure 9 shown, the present invention provides a best embodiment of a storage medium.

[0104] A storage medium 7, referring to Figure 9 , stores a computer program 71. When the computer program 71 is executed by a processor, the processor is caused to execute the steps of the method as described above.

[0105] Specifically, the storage medium 7 stores at least one computer program 71. The computer program 71 is used to be executed by a processor to implement the method as Figure 1 shown. For the detailed method, reference can be made to the above, and details will not be elaborated here. In one embodiment, the computer-readable storage medium 7 can be a storage chip in a terminal, a hard disk, a mobile hard disk, a USB flash drive, an optical disc or other writable and readable storage tools, or a server, etc.

[0106] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program 71. The program can be stored in a non-volatile computer-readable storage medium 7. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in the present application can include non-volatile and / or volatile memories. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0107] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0108] The above embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

[0109] The above are only the best embodiments of the present invention, and are not used to limit the scope of the present invention. Any equivalent changes or modifications made in accordance with the scope of the patent application of the present invention are all covered by the present invention.

Claims

1. A method for improving ranging accuracy, characterized in that, the method for improving ranging accuracy is applied to a lidar system, and specifically includes the following steps: Sampling at a first rate to obtain a current sampling sequence and calculating a current distance value; Sampling at a second rate and obtaining a reference signal; Performing downsampling on the reference signal with different phases to obtain multiple sampling sequences; Corresponding the phases to the sampling sequences one by one to form a sequence table; Presetting a correction table to reflect the corresponding relationship between the phase and the error value; Obtaining the current phase according to the current sampling sequence and the sequence table, and obtaining the current error value according to the current phase and the correction table; Obtaining the actual distance value according to the current distance value and the current error value.

2. The method for improving ranging accuracy according to claim 1, characterized in that, the calculation of the current distance value specifically includes the following steps: Obtaining the acquisition time of the current sampling sequence; Calculating the time difference between the acquisition time of the current sampling sequence and the corresponding emission time to obtain the flight time; Calculating the current distance value through the flight time and the speed of light.

3. The method for improving ranging accuracy according to claim 1, characterized in that: the second rate is higher than the first rate.

4. The method for improving ranging accuracy according to claim 1, characterized in that, the presetting of the correction table includes the following steps: Calculating a reference distance value according to the reference signal; Calculating multiple corresponding target distance values according to multiple sampling sequences; Comparing the multiple target distance values with the reference distance value respectively to obtain multiple error values corresponding to the sampling sequences; Corresponding the error values to the phases one by one according to the sequence table to form a correction table.

5. The method for improving ranging accuracy according to claim 4, characterized in that, the calculation of the reference distance value specifically includes the following steps: Obtaining the acquisition time of the reference signal; Calculating the time difference between the acquisition time of the reference signal and the corresponding emission time to obtain the flight time; Calculating the reference distance value through the flight time and the speed of light.

6. The method for improving ranging accuracy according to claim 4, characterized in that, the calculation of the target distance value specifically includes the following steps: Respectively obtaining the acquisition times of multiple sampling sequences; Calculating the time difference between the acquisition time of the sampling sequence and the corresponding emission time to obtain the flight time; Calculating the target distance value through the flight time and the speed of light.

7. A lidar, characterized in that: the lidar is used to implement the method according to any one of claims 1-6, and includes a laser unit, a scanning unit and a signal processing unit. The signal processing unit includes a photoelectric conversion module and an ADC sampling module. The laser unit is connected to the scanning unit, the scanning unit is connected to the photoelectric conversion module, the photoelectric conversion module is connected to the ADC sampling module, and the ADC sampling module is connected to the laser unit.

8. A rangefinder, characterized in that: It includes a storage unit and a processing unit. The storage unit stores a computer program. When the computer program is executed by the processing unit, the processing unit executes the steps of the method according to any one of claims 1-6.

9. A storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 6.

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