WO2021184206A1

WO2021184206A1 - Linear swept frequency correction method and device, storage medium, and system

Info

Publication number: WO2021184206A1
Application number: PCT/CN2020/079749
Authority: WO
Inventors: 何一雄
Original assignee: 深圳市速腾聚创科技有限公司
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2021-09-23
Also published as: CN114096873A

Abstract

A linear swept frequency correction method and device, a storage medium, and a system. The method comprises: generating a first drive current signal (S101); performing pre-correction on the first drive current signal, and obtaining a target drive current signal (S102); and determining the target drive current signal to be a linear swept frequency drive signal (S102). The method ensures that a first drive current signal can be corrected to generate a target drive current signal that meets swept frequency linearity requirements while meeting the requirements for low costs and real-time performance.

Description

Linear frequency sweep correction method, device, storage medium and system

Technical field

This application relates to the field of computer technology, and in particular to a linear frequency sweep correction method, device, storage medium and system.

Background technique

Lidar is a radar system that emits a laser beam to detect the target's position, speed and other characteristic quantities. The ranging principle of FMCW lidar is to emit a continuous wave with a linear change in frequency as the outgoing signal during the sweep period. A part of the outgoing signal is used as the local oscillator signal. There is a certain frequency difference with the local oscillator signal, and the distance information between the detected target and the radar can be obtained by measuring the frequency difference. Lidar is widely used in fields such as autonomous driving, robotics, aerial surveying and mapping due to its long detection range and high ranging accuracy.

Among them, the continuous wave whose emission frequency changes linearly in the frequency sweep period can be understood as the linear frequency sweep of the laser. The energy of the beat frequency spectrum of the linear sweep signal is concentrated on the signal frequency. However, in actual situations, the non-linearity of the frequency sweep will cause the frequency spectrum of the beat signal to widen, resulting in a decrease in the accuracy of ranging and speed measurement. At the same time, the signal amplitude will also decrease due to the energy diffusion to nearby frequency points, resulting in a decrease in the signal-to-noise ratio, resulting in The maximum ranging range of the system is reduced. Therefore, improving the frequency sweep linearity of the frequency sweep light source is particularly important for FMCW lidar systems.

At present, there are many ways to overcome the nonlinearity of the frequency sweep of the lidar system, and the system structure is complicated and it is difficult to meet the requirements of high linearity.

Summary of the invention

The embodiments of the present application provide a linear frequency sweep correction method, device, storage medium, and system. Under the condition of ensuring low cost and real-time requirements, the first drive current signal can be corrected to generate a target that meets the frequency sweep linearity requirements. Drive current signal. The technical solution is as follows:

In the first aspect, an embodiment of the present application provides a linear frequency sweep correction method, and the method includes:

Generating a first driving current signal;

Pre-correcting the first drive current signal to obtain a target drive current signal;

The target drive current signal is determined as a linear frequency sweep drive signal.

In the second aspect, an embodiment of the present application provides a linear frequency sweep correction method, and the method includes:

Generating a first driving current signal;

Performing iterative approximation correction on the first drive current signal to obtain a target drive current signal;

In a third aspect, an embodiment of the present application provides a linear frequency sweep correction device, and the device includes:

A signal generating module for generating a first driving current signal;

A pre-correction module, configured to pre-correct the first drive current signal to obtain a target drive current signal;

The signal determining module is used to determine the target drive current signal as a linear frequency sweeping drive signal.

In a fourth aspect, an embodiment of the present application provides a linear frequency sweep correction device, and the device includes:

A signal generating module for generating a first driving current signal;

An iterative correction module, configured to iteratively approximate and correct the first drive current signal to obtain a target drive current signal;

In a fifth aspect, an embodiment of the present application provides a computer storage medium that stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the linear frequency sweep correction method described above.

In a sixth aspect, an embodiment of the present application provides a laser linear frequency sweep correction system, which may include: a processor and a memory; wherein the memory stores a computer program, and the computer program is suitable for being loaded and executed by the processor The linear frequency sweep correction method described above.

The beneficial effects brought about by the technical solutions provided by some embodiments of the present application include at least:

In one or more embodiments of the present application, the first drive current signal is pre-corrected to obtain the target drive current signal that meets the frequency sweep linearity requirement, or the first drive current signal is iteratively approximated and corrected to obtain the target drive current signal that meets the frequency sweep Linearity requires the target drive current signal, there is no need to add other hardware and additional algorithms in the actual FMCW system. Under the condition of ensuring low cost and real-time requirements, the first drive current signal can be corrected to generate a target that meets the sweep linearity requirements The driving current signal, in actual work, the laser can be swept according to the corrected waveform as the driving signal.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic diagram of an example of an FMCW ranging principle provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of time-frequency waveforms of linear frequency sweep and nonlinear frequency sweep provided by an embodiment of the present application;

3 is a schematic diagram of an example of a linear frequency amplitude waveform and a nonlinear frequency waveform provided by an embodiment of the present application;

4 is a schematic flowchart of a linear frequency sweep correction method provided by an embodiment of the present application;

FIG. 5 is a schematic flowchart of a signal pre-correction method provided by an embodiment of the present application;

6 is a schematic structural diagram of a laser linear frequency sweep correction system provided by an embodiment of the present application;

FIG. 7 is a schematic flowchart of a linear frequency sweep correction method provided by an embodiment of the present application;

FIG. 8 is a schematic flowchart of a signal iterative approximation correction method provided by an embodiment of the present application;

FIG. 9 is a schematic flowchart of a linear frequency sweep correction method provided by an embodiment of the present application;

FIG. 10 is a schematic structural diagram of a linear frequency sweep correction device provided by an embodiment of the present application;

FIG. 11 is a schematic structural diagram of a linear frequency sweep correction device provided by an embodiment of the present application;

FIG. 12 is a schematic structural diagram of a laser linear frequency sweep correction system provided by an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

In the description of this application, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In the description of this application, it should be noted that, unless otherwise clearly stipulated and limited, "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes unlisted steps or units, or optionally also includes Other steps or units inherent to these processes, methods, products or equipment. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood under specific circumstances. In addition, in the description of this application, unless otherwise specified, "plurality" means two or more. "And/or" describes the association relationship of the associated objects, indicating that there can be three types of relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone. The character "/" generally indicates that the associated objects before and after are in an "or" relationship.

For lidars, such as frequency modulated continuous wave (FMCW) lidars, the coherent detection principle is used to achieve speed and distance measurement. The system emits continuous lasers with linear changes in frequency (triangular or sawtooth) during the frequency sweep period. The echo light reflected by the object interferes with the local oscillation light on the reference arm, and the generated beat signal is detected by the photodetector. The distance and speed of the target are calculated by measuring the frequency of the beat signal. As shown in Figure 1, the center wavelength of the sweep laser is λ, the sweep period is T, the sweep bandwidth is B, and the beat signals are f _b- and f _b+ , then the distance to the target can be obtained

And speed

FMCW lidar is a continuous wave lidar based on coherent detection. A light source with continuously changing frequency is needed. The frequency sweep range is usually from hundreds of MHz to tens of GHz. Triangular waves are generally used for modulation, and the modulation frequency is generally 10 kHz to 100 kHz. Moreover, FMCW lidar has high requirements for the continuity and linearity of the outgoing signal, so that the difference between the local oscillator signal and the echo signal is stable, avoiding the introduction of other variables due to nonlinear waveform changes. Generally, current-modulated distributed feedback (DFB) semiconductor lasers or external cavity semiconductor lasers (External Cavity Diode Lasers, ECDL) can be used as the light source.

FMCW uses the principle of coherent detection and has high ranging accuracy; compared with direct detection, it has strong anti-interference; it can measure speed and distance at the same time; and continuous light emission does not require high peak power and has low system power consumption. The advantages of human eye safety are widely used in fields such as autonomous driving, robotics, and aerial surveying and mapping.

According to the different principles of frequency modulation, frequency modulation lasers are divided into mechanical frequency modulation, temperature frequency modulation and current frequency modulation lasers, etc. However, in either way, the length, temperature and carrier concentration of the laser cavity are controlled by external drive currents. Wait for changes to change the laser output frequency. As shown in Figure 2, the drive current is a triangular wave. Under ideal conditions, the frequency should change strictly linearly with time. However, in actual situations, the laser output frequency is not a linear relationship with the drive current, so the frequency sweep of the FM laser is nonlinear. When the ratio of the maximum frequency deviation in the sweep frequency range |Δf _max | to the sweep frequency range B is smaller, it indicates that the sweep linearity is better.

Among them, linearity is defined as the ratio of the maximum frequency deviation in the sweep frequency range |Δf _max | to the sweep frequency range B, that is, L=|Δf _max |/B

The smaller the L, the better the linearity.

The beat frequency spectrum of a strictly linear frequency sweep signal is shown in Figure 3(a), where the energy is concentrated on the signal frequency. However, in actual situations, the non-linearity of the frequency sweep will cause the frequency spectrum of the beat signal to widen, as shown in Figure 3(b), resulting in a decrease in the accuracy of ranging and speed measurement. At the same time, the signal amplitude will also follow due to energy diffusion to nearby frequency points. Decrease, causing the signal-to-noise ratio to decrease, resulting in a decrease in the maximum ranging range of the system. Therefore, improving the sweep linearity of the swept frequency light source is particularly important for the FMCW system.

The linear frequency sweep correction method provided by the embodiments of the present application will be described in detail below in conjunction with specific embodiments. The method can be realized by relying on a computer program, and can be run on a linear frequency sweep correction device based on the von Neumann system. The computer program can be integrated in the application or run as an independent tool application. The linear frequency sweep correction device in the embodiment of the present application may be a laser linear frequency sweep system, and the laser is a frequency modulated laser.

Please refer to FIG. 4, which is a schematic flowchart of a linear frequency sweep correction method provided by an embodiment of this application. Including pre-correction, as shown in FIG. 4, the method of the embodiment of the present application may include the following steps:

S101, generating a first driving current signal;

In order to ensure the linearity of the frequency sweep of the laser, the modulation signal needs to be adjusted.

Specifically, the first driving current signal is an initial modulation signal for loading on the laser. Wherein, an arbitrary waveform generator (such as a function signal generator) can be used to generate the first driving current signal I ₁ (t).

S102: Perform pre-correction on the first drive current signal to obtain a target drive current signal;

Suppose that under linear modulation (triangular wave), that is, when the modulation signal is I(t)=k*t+b, the frequency-time function of the laser output is f(t)=f[I(t)]=f(k*t +b); As mentioned above, since the frequency of the laser output and the first drive current signal are not linear, f(t) is a non-linear function.

If the modulation signal is converted into I 'frequency function of time ^{(t) = f -1 (k} * t + b), the laser output is f' (t) = f '[I' (t)] = f [f - ¹ (k*t+b)]=k*t+b. Obviously, f'(t) is a linear function at this time.

Therefore, the drive current signal can be corrected to the inverse function of the laser frequency time function under linear modulation to achieve linearity pre-correction, and the pre-corrected modulation signal is the target drive current signal.

For the specific pre-correction process, please refer to S201 and S202, as shown in Figure 5:

S201: Obtain a first time-frequency function corresponding to the first driving current signal;

Figure 6 shows a schematic diagram of a laser linear frequency sweeping system, where the arbitrary waveform generator is used to randomly generate the first drive current signal and input it to the frequency modulated laser to inject a rated working current into the laser to make the laser emit light normally. The output of the laser is passed through a Mach-Zehnder Interferometer (Mach-Zehnder Interferometer) to generate an optical beat frequency signal, which is measured with a balanced detector. The beat frequency time domain signal is obtained through a data collector (or oscilloscope), and the time domain signal is processed by the host computer. Processing and analysis, such as using a host computer to perform Hilbert transform or Fourier transform on the time-domain signal of the balanced detector, or using an optical discriminator to calculate the first time-frequency function f ₁ (t).

S202: Calculate an inverse function of the first time-frequency function, and use the inverse function as a target drive current signal.

The first drive current signal is

S103: Determine the target drive current signal as a linear frequency sweep drive signal.

S104, storing the linear frequency sweeping drive signal.

Store the drive signal in the FMCW system, and in actual work, the laser can be scanned according to the corrected waveform as the drive signal to meet the linearity requirements.

In the embodiment of the present application, by pre-correcting the first drive current signal, a target drive current signal that meets the frequency sweep linearity requirement can be obtained. There is no need to add other hardware and additional algorithms to the actual FMCW system. Under the condition of ensuring low cost and real-time requirements, the first drive current signal can be corrected to generate a target drive current signal that meets the sweep linearity requirements. Just follow the correction waveform as the drive signal to sweep the laser.

Please refer to FIG. 7, which is a schematic flowchart of a linear frequency sweep correction method provided by an embodiment of this application. Including iterative approximation correction, as shown in FIG. 7, the method of the embodiment of the present application may include the following steps:

S301: Generate a first driving current signal;

It can be understood that the first driving current signal is a randomly generated initial current signal for loading on the laser. Can be generated by a random generator. Wherein, an arbitrary waveform generator (such as a function signal generator) can be used to generate the first driving current signal I ₁ (t).

S302: Perform iterative approximation correction on the first drive current signal to obtain a target drive current signal;

For the specific iterative approximation correction process, please refer to S401 and S405, as shown in Figure 8:

S401: Obtain a first time-frequency function and a theoretical time-frequency function corresponding to the first driving current signal;

As shown in Figure 6, the pre-corrected output signal I ₁ (t) is first used as the initial input signal I _k (t) for iterative approximation correction, and the arbitrary waveform generator is used to drive the laser with sweep frequency. The output of the laser passes through Mach. The Zendell interferometer generates the optical beat frequency signal and measures it with a balanced detector. The beat frequency time domain signal is obtained through a data collector (or oscilloscope). The upper computer is used to transform the time domain signal of the balanced detector to obtain I _k (t) corresponds to the first time frequency function f _k (t). At the same time, calculate the theoretical time-frequency function F(t). Among them, F(t) is a linear function.

S402: Calculate the difference between the theoretical time-frequency function and the first time-frequency function, and use the difference as an error function;

Based on the error function and the linearity threshold, iterative approximation correction is performed on the first drive current signal to obtain a target drive current signal after iterative approximation correction.

Specifically, the error function e _k (t) = F (t)-f _k (t).

S403: When the maximum value of the absolute value of the error function is less than the linearity threshold, use the second drive current signal as a target drive current signal;

The linearity threshold is L. When max|e _k (t)|<L, it indicates that f _k (t) can meet the requirements of linear frequency sweep, then the second drive current signal I ₁ (t) is the linear frequency sweep drive Signal.

S404: When the maximum value of the absolute value of the error function is not less than the linearity threshold, adjust the first driving current signal to generate a second driving current signal;

When the maximum value of the absolute value of the error function is not less than the linearity threshold, calculating the product of the error function and the preset weight;

When max|e _k (t)|≥L, it indicates that f _k (t) still cannot meet the linear frequency sweep requirement, and it is necessary to continue to adjust the first drive current signal I _k (t). Specifically, calculate a·e _k (t), where a is the coefficient of the drive current with frequency error.

The second drive current signal I _k+1 (t)=I _k (t)+a·e _k (t)

S405, using the second driving current signal as the first driving current signal, and performing the step of obtaining the first time frequency function and the theoretical time frequency function corresponding to the first driving current signal.

Take the corrected signal I _k+1 (t) as the new input waveform. In the input value laser, repeat the above steps until _{the maximum value of the frequency error-time function e k} (t) is less than the linearity index L required by the system .

S303: Determine the target drive current signal as a linear frequency sweep drive signal.

S304: Store the linear frequency sweep driving signal.

In the embodiment of the present application, by iteratively approximating and correcting the first drive current signal, a target drive current signal that meets the frequency sweep linearity requirement is obtained. There is no need to add other hardware and additional algorithms to the actual FMCW system. Under the condition of ensuring low cost and real-time requirements, the first drive current signal can be corrected to generate a target drive current signal that meets the sweep linearity requirements. Just follow the correction waveform as the drive signal to sweep the laser. Compared with the traditional open-loop correction method, the correction effect does not depend on the numerical model of the frequency modulated laser. This method can achieve linearity L<0.001 through the iterative approximation method.

Please refer to FIG. 9, which is a schematic flowchart of a linear frequency sweep correction method provided by an embodiment of this application, including pre-correction and iterative approximation correction. As shown in FIG. 9, the method of the embodiment of the present application may include the following steps:

S501: Generate a first driving current signal;

The laser linear frequency sweep correction system shown in Figure 6, the purpose of the whole system is to obtain the corrected drive current waveform I(t) at the preset chirp frequency, to ensure that under the modulation of the drive waveform, the laser output The frequency-time curve f(t) satisfies the linearity requirement. Among them, an arbitrary waveform generator (function signal generator) is used to generate the modulated signal I ₁ (t) and applied to the frequency modulated laser.

S502, performing pre-correction on the first driving current signal to obtain a second driving current signal;

For the pre-correction principle, refer to S102, which will not be repeated here.

Specifically, the output I ₁ (t) of the laser generates an optical beat frequency signal through the Mach-Zehnder Interferometer, and is measured with a balanced detector. The beat frequency time domain signal is obtained through a data collector (or oscilloscope), and the time domain signal is measured by the host computer. Perform processing and analysis to generate a new modulation waveform, that is, the second drive current signal I'(t).

Generally, this pre-calibration method can only improve the frequency sweep linearity of the laser initially, reduce the frequency sweep linearity L to about 0.05, and cannot further improve the linearity. The specific reason is that the pre-correction process considers the frequency-current impulse response function as an ideal δ function. In actual situations, due to the principle of laser frequency modulation, the response bandwidth cannot be infinitely large, so the frequency-current impulse response function cannot be fully considered as Ideal delta function. It needs to be corrected by iterative approximation to achieve a further improvement in linearity.

S503: Perform iterative approximation correction on the second drive current signal to obtain a target drive current signal;

First, use the second drive current signal I'(t) output from the pre-calibration module as the initial input waveform I _k (t) of the iterative approximation module, and use an arbitrary waveform generator to drive the laser with frequency sweeping. Then use the host computer to perform a time-frequency domain transform (such as Hilbert transform) on the time-domain signal of the balanced detector, and calculate the frequency-time curve f _k (t). _{Then calculate the frequency error-time function e k} (t)=F(t)-f _k (t) between the actual frequency-time function f _k (t) and the ideal linear sweep frequency-time function F(t). Determine whether the maximum value of the frequency error-time function e _k (t) is less than the linearity index L required by the system. If it is satisfied, then the drive current I _k (t) is the correction waveform that you want to obtain; if it is not satisfied, It is necessary to iteratively correct the drive current I _k (t) according to the error-time function e _k (t), and the corrected drive current signal is I _k+1 (t) = I _k (t) + a·e _k ( t).

Where a is the coefficient of the drive current with frequency error, and the corrected waveform I _k+1 (t) is taken as the new input waveform and substituted into the iterative approximation module, and the above steps are repeated until the frequency error-time function e _k (t) The maximum value of is less than the linearity index L required by the system.

S504: Determine the target drive current signal as a linear frequency sweep drive signal.

S505: Store the linear frequency sweep driving signal.

Store the driving signal in the FMCW system. In actual work, the laser can be scanned according to the corrected waveform as the driving signal to meet the linearity requirements.

In one or more embodiments of the present application, by pre-correcting the first drive current signal and performing iterative approximation correction on the pre-corrected second drive current signal, the target drive current signal that meets the linearity requirement of the sweep can be obtained. There is no need to add other hardware and additional algorithms to the actual FMCW system. Under the condition of ensuring low cost and real-time requirements, the first drive current signal can be corrected to generate a target drive current signal that meets the sweep linearity requirements. Just follow the correction waveform as the drive signal to sweep the laser.

The following are device embodiments of this application, which can be used to implement the method embodiments of this application. For details that are not disclosed in the device embodiments of this application, please refer to the method embodiments of this application.

Please refer to FIG. 10, which shows a schematic structural diagram of a linear frequency sweep correction device provided by an exemplary embodiment of the present application. The linear frequency sweep correction device can be implemented as all or a part of the laser through software, hardware or a combination of the two. The device 1 includes a signal generation module 11, a pre-correction module 12 and a signal determination module 13.

The signal generating module 11 is used to generate a first driving current signal;

The pre-correction module 12 is used to pre-correct the first drive current signal to obtain a target drive current signal;

The signal determining module 13 is used to determine the target drive current signal as a linear frequency sweeping drive signal.

Optionally, the pre-correction module 12 is specifically used for:

Acquiring a first time-frequency function corresponding to the first driving current signal;

Calculate the inverse function of the first time-frequency function, and use the inverse function as a second drive current signal.

Optionally, the signal determining module 13 is further configured to:

When the inverse function is a linear function, the second drive current signal is determined as a linear frequency sweep drive signal.

Optionally, the device further includes:

The signal storage module 14 is used to store the linear frequency sweep driving signal.

It should be noted that when the linear frequency sweep correction device provided in the above embodiment executes the linear frequency sweep correction method, only the division of the above-mentioned functional modules is used as an example for illustration. In actual applications, the above-mentioned function allocation can be different according to needs. The function module is completed, that is, the internal structure of the device is divided into different function modules to complete all or part of the functions described above. In addition, the linear frequency sweep correction device provided by the foregoing embodiment belongs to the same concept as the embodiment of the linear frequency sweep correction method. For the implementation process of the linear frequency sweep correction method, please refer to the method embodiment, which will not be repeated here.

The serial numbers of the foregoing embodiments of the present application are for description only, and do not represent the superiority or inferiority of the embodiments.

Please refer to FIG. 11, which shows a schematic structural diagram of a linear frequency sweep correction device provided by an exemplary embodiment of the present application. The linear frequency sweep correction device can be implemented as all or a part of the laser through software, hardware or a combination of the two. The device 2 includes a signal generation module 21, an iterative correction module 22 and a signal determination module 23.

The signal generating module 21 generates a first driving current signal;

The iterative correction module 22 is configured to iteratively approximate and correct the first drive current signal to obtain a target drive current signal;

The signal determining module 23 is configured to determine the target drive current signal as a linear frequency sweeping drive signal.

Optionally, the iterative correction module 22 is specifically configured to:

Acquiring a second time-frequency function corresponding to the second driving current signal and a theoretical time-frequency function;

Calculating the difference between the theoretical time-frequency function and the second time-frequency function, and using the difference as an error function;

Based on the error function and the linearity threshold, the iterative approximation correction is performed on the second drive current signal to obtain the target drive current signal after iterative approximation correction.

Optionally, the iterative correction module 22 is specifically configured to:

When the maximum value of the absolute value of the error function is less than the linearity threshold, using the second drive current signal as the target drive current signal;

When the maximum absolute value of the error function is not less than the linearity threshold, adjusting the second driving current signal to generate a third driving current signal;

The third driving current signal is used as the second driving current signal, and the step of obtaining the second time frequency function and the theoretical time frequency function corresponding to the second driving current signal is performed.

Optionally, the iterative correction module 22 is specifically configured to:

The sum of the product and the second drive current signal is determined as a third drive current signal.

Optionally, the device further includes:

The signal storage module 24 is used to store the linear frequency sweep driving signal.

The embodiment of the present application also provides a computer storage medium. The computer storage medium may store a plurality of instructions, and the instructions are suitable for being loaded by a processor and executed as described in the embodiments shown in FIGS. 4-9. For the application monitoring method, the specific execution process can refer to the specific description of the embodiment shown in FIG. 4 to FIG. 9, which will not be repeated here.

Fig. 12 shows a Von Neumann system-based linear frequency sweep correction system 12 that runs the above linear frequency sweep correction method. Specifically, it may include an external input interface 1001, a processor 1002, a memory 1003, and an output interface 1004 connected through a system bus. Wherein, the external input interface 1001 may include a touch screen 10016, and optionally may also include a network interface 10018. The storage 1003 may include an external storage 10032 (for example, a hard disk, an optical disk, or a floppy disk, etc.) and an internal storage 10034. The output interface 1004 may include equipment such as a display screen 10042 and a speaker/speaker 10044.

In this embodiment, the operation of this method is based on a computer program. The program file of the computer program is stored in the external memory 10032 of the aforementioned von Neumann system-based computer system 10, and is loaded into the internal memory 10034 during operation. It is then compiled into machine code and then transferred to the processor 1002 for execution, so that a logical signal generation module, a pre-correction module, an iterative correction module, a signal determination module, and a signal storage are formed in the computer system 10 based on the von Neumann system. Module. In addition, during the execution of the above linear frequency sweep correction method, the input parameters are received through the external input interface 1001 and transferred to the memory 1003 for buffering, and then input to the processor 1002 for processing, and the processed result data may be buffered in the memory 1003 It is processed later or passed to the output interface 1004 for output.

A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing relevant hardware through a computer program. The program can be stored in a computer readable storage medium. During execution, it may include the procedures of the above-mentioned method embodiments. Wherein, the storage medium can be a magnetic disk, an optical disc, a read-only storage memory, or a random storage memory, etc.

The above-disclosed are only preferred embodiments of this application, and of course the scope of rights of this application cannot be limited by this. Therefore, equivalent changes made according to the claims of this application still fall within the scope of this application.

Claims

A linear frequency sweep correction method, characterized in that the method includes:

Generating a first driving current signal;

Pre-correcting the first drive current signal to obtain a target drive current signal;

The target drive current signal is determined as a linear frequency sweep drive signal.
The method according to claim 1, wherein the pre-correcting the first drive current signal to obtain the target drive current signal comprises:

Acquiring a first time-frequency function corresponding to the first driving current signal;

The inverse function of the first time-frequency function is calculated, and the inverse function is used as a target drive current signal.
The method according to claim 2, wherein after said calculating the inverse function of the first time-frequency function and using the inverse function as a target drive current signal, the method further comprises:

When the inverse function is a linear function, the target drive current signal is determined as a linear frequency sweep drive signal.
The method according to claim 1, wherein after determining the target drive current signal as a linear frequency sweeping drive signal, the method further comprises:

Store the linear frequency sweep driving signal.
A linear frequency sweep correction method, characterized in that the method includes:

Generating a first driving current signal;

Performing iterative approximation correction on the first drive current signal to obtain a target drive current signal;

The target drive current signal is determined as a linear frequency sweep drive signal.
The method according to claim 5, wherein the iterative approximation correction of the first drive current signal to obtain the target drive current signal comprises:

Acquiring a first time-frequency function corresponding to the first driving current signal and a theoretical time-frequency function;

Calculating the difference between the theoretical time-frequency function and the first time-frequency function, and using the difference as an error function;

Based on the error function and the linearity threshold, iterative approximation correction is performed on the first drive current signal to obtain a target drive current signal after iterative approximation correction.
The method according to claim 6, wherein the iterative approximation correction of the first drive current signal based on the error function and the linearity threshold to obtain the target drive current signal after the iterative approximation correction comprises :

When the maximum value of the absolute value of the error function is less than the linearity threshold, using the first drive current signal as the target drive current signal;

When the maximum value of the absolute value of the error function is not less than the linearity threshold, adjusting the first driving current signal to generate a second driving current signal;

The second driving current signal is used as the first driving current signal, and the step of obtaining the second time frequency function and the theoretical time frequency function corresponding to the first driving current signal is performed.
8. The method of claim 7, wherein when the maximum value of the absolute value of the error function is not less than the linearity threshold, adjusting the first driving current signal to generate a second driving current signal, include:

When the maximum value of the absolute value of the error function is not less than the linearity threshold, calculating the product of the error function and the preset weight;

The sum of the product and the first drive current signal is determined as a second drive current signal.
The method according to claim 5, wherein after determining the target drive current signal as a linear frequency sweeping drive signal, the method further comprises:

Store the linear frequency sweep driving signal.
A computer storage medium, wherein the computer storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the method according to any one of claims 1 to 4 or 5 to 9 .
A laser linear frequency sweep correction system, comprising: a processor and a memory; wherein the memory stores a computer program, and the computer program is adapted to be loaded by the processor and executed as claimed in claims 1 to 4. Or the method described in any one of 5-9.