CN116265982A - Signal enhancement method and device, OPA laser radar and storage medium - Google Patents
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Abstract
The application is applicable to the technical field of signal processing and provides a signal enhancement method, a signal enhancement device, an OPA laser radar and a storage medium. Wherein the signal enhancement method comprises: acquiring first frequency spectrums corresponding to N difference frequency signals of a target detection object, wherein the first frequency spectrums comprise frequency spectrum serial numbers and frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers, and N is an integer greater than 1; performing point multiplication operation on the N spectrum amplitudes with the same spectrum sequence number in the first frequency to obtain a signal-to-noise ratio of
X is the second frequency spectrum of (2) 1 Signal to noise ratio for a single said first frequency spectrum; and determining the frequency of the difference frequency signal according to the second frequency spectrum. The accuracy of the frequency measurement result of the difference frequency signal can be improved through the method and the device.
Description
Technical Field
The application belongs to the technical field of signal processing, and particularly relates to a signal enhancement method, a signal enhancement device, an OPA laser radar and a storage medium.
Background
When the transmitting signal of the optical phased array (Optical Phased Array, OPA) laser radar is transmitted in space, an echo signal can be formed if an obstacle is encountered, a difference frequency signal is generated after the echo signal is mixed with the current local oscillation signal, and the distance between the obstacle and the OPA laser radar can be obtained according to the frequency of the difference frequency signal. However, noise is typically present in the echo signal, resulting in a lower signal-to-noise ratio of the echo signal, which reduces the accuracy of the frequency measurement of the difference signal.
Disclosure of Invention
The embodiment of the application provides a signal enhancement method, a signal enhancement device, an OPA laser radar and a storage medium, so as to improve the accuracy of a frequency measurement result of a difference frequency signal.
In a first aspect, an embodiment of the present application provides a signal enhancement method applied to an OPA lidar, where the signal enhancement method includes:
acquiring first frequency spectrums corresponding to N difference frequency signals of a target detection object, wherein the first frequency spectrums comprise frequency spectrum serial numbers and frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers, and N is an integer greater than 1;
performing point multiplication operation on the N spectrum amplitudes with the same spectrum sequence number in the first frequency to obtain a signal-to-noise ratio of
X is the second frequency spectrum of (2) 1 Signal to noise ratio for a single said first frequency spectrum;
and determining the frequency of the difference frequency signal according to the second frequency spectrum.
In a second aspect, an embodiment of the present application provides a signal enhancement device applied to an OPA lidar, where the signal enhancement device includes:
the frequency spectrum acquisition module is used for acquiring first frequency spectrums corresponding to N difference frequency signals of a target detection object, wherein the first frequency spectrums comprise frequency spectrum serial numbers and frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers, and N is an integer larger than 1;
the point multiplication operation module is used for carrying out point multiplication operation on the N frequency spectrum amplitudes with the same frequency spectrum sequence number in the first frequency spectrum to obtain a signal to noise ratio of
X is the second frequency spectrum of (2) 1 Signal to noise ratio for a single said first frequency spectrum;
and the frequency determining module is used for determining the frequency of the difference frequency signal according to the second frequency spectrum.
In a third aspect, embodiments of the present application provide an OPA lidar comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the signal enhancement method according to the first aspect described above when the computer program is executed by the processor.
In a fourth aspect, embodiments of the present application provide a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the signal enhancement method according to the first aspect described above.
In a fifth aspect, embodiments of the present application provide a computer program product which, when run on an OPA lidar, causes the OPA lidar to perform the steps of the signal enhancement method as described in the first aspect above.
From the above, the signal strength can be enhanced by acquiring the first frequency spectrums corresponding to the N difference frequency signals of the target detection object, and performing the point multiplication operation on the spectrum amplitudes with the same spectrum serial numbers in the N first frequency spectrums, so as to obtain the signal-to-noise ratio of
The signal-to-noise ratio of the second frequency spectrum is improved compared to the single first frequency spectrum>
Double, improved according to signal to noise ratio->
The multiplied second frequency spectrum can accurately measure the frequency of the difference frequency signalThe accuracy of the frequency measurement result of the difference frequency signal is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of an implementation of a signal enhancement method according to an embodiment of the present application;
FIG. 2a is an exemplary diagram of a single first frequency spectrum;
FIG. 2b is an exemplary diagram of a second frequency spectrum;
fig. 3 is a schematic implementation flow chart of a signal enhancement method according to a second embodiment of the present application;
fig. 4 is a schematic flow chart of an implementation of a signal enhancement method according to the third embodiment of the present application;
fig. 5 is a schematic structural diagram of a signal enhancement device according to a fourth embodiment of the present application;
fig. 6 is a schematic structural diagram of an OPA lidar provided in a fifth embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
As used in this specification and the appended claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
In addition, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.
It should be understood that the sequence number of each step in this embodiment does not mean the sequence of execution, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.
In order to illustrate the technical solutions described in the present application, the following description is made by specific examples.
Referring to fig. 1, a schematic implementation flow diagram of a signal enhancement method according to an embodiment of the present application is provided, where the signal enhancement method is applied to OPA lidar. As shown in fig. 1, the signal enhancement method may include the steps of:
Wherein N is an integer greater than 1.
The target detection object may be a static object or a moving object, such as a vehicle, a pedestrian, an unmanned aerial vehicle, etc., and the specific type of the target detection object is not limited in the present application.
The OPA laser radar can emit detection signals to the target detection object, the target detection object can reflect echo signals to the OPA laser radar based on the detection signals, and after the OPA laser radar receives the echo signals, the echo signals are mixed with the current local oscillation signals, so that difference frequency signals can be obtained. The probe signal can be understood as the emission signal of the OPA lidar.
The OPA lidar comprises a transmitting array, wherein optical signals are transmitted through a transmitting unit in the transmitting array, and the optical signals can be divided into two paths of signals, namely local oscillation signals and detection signals after sequentially passing through an electro-optical modulator and a beam splitter (such as a 1×2 beam splitter). The local oscillator signal is used for mixing.
For the ith difference frequency signal of the target detection object, the ith difference frequency signal is any one of N difference frequency signals, and a first frequency spectrum corresponding to the ith difference frequency signal can be obtained by performing fast Fourier transform on the ith difference frequency signal. The specific number of the frequency domain sampling points of the fast fourier transform is not limited, but the frequency domain sampling points when the fast fourier transform is performed on the N difference frequency signals are required to be the same, so as to calculate the point multiplication accumulation of the frequency spectrum in step 102.
The spectral sequence numbers are related to the spectral analysis length of the fourier transform, and each spectral sequence number corresponds to a spectral amplitude. For example, the spectrum analysis length is 4096, then the spectrum sequence number is 0 to 4095, and the frequency spectrum includes 4096 spectrum sequence numbers and the spectrum amplitude corresponding to each of the 4096 spectrum sequence numbers.
102, performing a point multiplication operation on the spectrum amplitudes with the same spectrum sequence numbers in the N first frequencies to obtain a signal-to-noise ratio of
X is the second frequency spectrum of (2) 1 Is the signal to noise ratio of the single first frequency spectrum.
The point multiplication and accumulation of the N first frequency spectrums can be realized by carrying out the point multiplication operation on the frequency spectrum amplitudes with the same frequency spectrum serial numbers in the N first frequency spectrums, thereby enhancing the signal strength and obtaining the signal to noise ratio to improve
A second frequency spectrum of multiples.
An exemplary diagram of a single first frequency spectrum is shown in fig. 2 a; an example plot of the second frequency spectrum is shown in fig. 2 b. Compared to fig. 2a, the signal strength of the second frequency spectrum in fig. 2b is increased, the noise strength is reduced, and thus an improvement of the signal-to-noise ratio is achieved. Wherein the spectral amplitude in the frequency spectrum corresponds to the signal strength.
In one embodiment, the N first frequency spectrum magnitudes with the same spectrum sequence number are subjected to a point multiplication operation to obtain a signal to noise ratio of
Comprises:
performing point multiplication operation on the spectrum amplitudes with the same spectrum sequence number in the N first frequency spectrums to obtain signal power of a second frequency spectrum;
determining the noise power of the second frequency spectrum according to the single noise power;
calculating the signal-to-noise ratio of the second frequency spectrum according to the signal power of the second frequency spectrum and the noise power of the second frequency spectrum;
wherein ,
x N for the signal-to-noise ratio of the second frequency spectrum, A 2N For the signal power of the second frequency spectrum, A is the amplitude of the echo signal, +.>
For noise power, sigma, of the second frequency spectrum 2 Is a single noise power.
The OPA laser radar performs point multiplication operation on the frequency spectrum amplitudes with the same frequency spectrum sequence numbers in the N first frequency spectrums, so that point multiplication accumulation on the N first frequency spectrums can be realized, a second frequency spectrum is obtained, and a signal-to-noise ratio of the second frequency spectrum can be obtained through calculation according to the signal power of the second frequency spectrum and the noise power of the second frequency spectrum.
Assuming that the echo signal is a complex signal contaminated with additive noise
The power of the noise (i.e. the power of a single noise) is sigma 2 Then the signal-to-noise ratio of the single first frequency spectrum +.>
Where the signal-to-noise ratio of a single first frequency spectrum can be understood as the signal-to-noise ratio of a single echo signal. />
The phase of the echo signal is represented, e represents a natural index, and j represents an imaginary unit.
Since one difference frequency signal corresponds to one echo signal, then N difference frequency signals correspond to N echo signals, and since the noise parts of the N echo signals are independent of each other, then the noise power of the second frequency spectrum is the accumulation of the single noise power
According to the signal-to-noise ratio, improve
The second frequency spectrum of the times can accurately measure the frequency of the difference frequency signal, and the accuracy of the frequency measurement result of the difference frequency signal is improved.
According to the signal-to-noise ratio, improve
The frequency of the difference frequency signal obtained by the double second frequency spectrum measurement can accurately obtain the distance between the target detection object and the OPA laser radar, and the distance measuring capability of the OPA laser radar is improved.
Shown in table 1 are distances measured based on a single first frequency spectrum and distances measured cumulatively based on the dot product of three first frequency spectrums.
Table 1 is an example of distances measured three times. As can be seen from table 1, the distance measured based on the point multiplication accumulation of d three first frequency spectrums is closer to the actual distance, which indicates that the distance measurement capability of the OPA lidar can be improved and a more accurate distance can be obtained in this embodiment.
In one embodiment, determining the frequency of the difference frequency signal from the second frequency spectrum comprises:
comparing the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the second frequency spectrum to obtain a second maximum value, wherein the second maximum value is the maximum value in the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the second frequency spectrum;
and determining the frequency of the difference frequency signal according to the frequency spectrum sequence number corresponding to the second maximum value.
Wherein the second maximum is the peak of the second frequency spectrum.
The frequency= (sampling frequency×spectrum number)/spectrum analysis length of the difference frequency signal can be calculated according to the spectrum number corresponding to the second maximum value, the sampling frequency of the fast fourier transform, and the spectrum analysis length.
According to the embodiment of the application, the N difference frequency signals aiming at the target detection object are respectively corresponding to the first frequency spectrums, and the N first frequency spectrums are subjected to point multiplication operation on the frequency spectrum amplitudes with the same frequency spectrum sequence number, so that the signal strength can be enhanced, and the signal-to-noise ratio is obtained
The signal-to-noise ratio of the second frequency spectrum is improved compared to the single first frequency spectrum>
Double, improved according to signal to noise ratio->
The second frequency spectrum of the times can accurately measure the frequency of the difference frequency signal, and the accuracy of the frequency measurement result of the difference frequency signal is improved.
Referring to fig. 3, a schematic implementation flow chart of a signal enhancement method provided in a second embodiment of the present application is applied to an OPA laser radar, where the OPA laser radar includes N groups of antenna arrays, and N is an integer greater than 1. As shown in fig. 3, the signal enhancement method may include the steps of:
in step 301, a detection signal is transmitted to the target probe, where the detection signal is used to indicate that the target probe reflects an echo signal.
The target detection object may be a static object or a moving object, such as a vehicle, a pedestrian, an unmanned aerial vehicle, etc., and the specific type of the target detection object is not limited in the present application.
The OPA laser radar comprises a transmitting array, wherein the transmitting unit in the transmitting array is used for transmitting optical signals, and the optical signals can be divided into two paths of signals, namely local oscillation signals and detection signals after sequentially passing through an electro-optical modulator and a 1 multiplied by 2 beam splitter. The local oscillator signal is used for mixing.
The OPA laser radar comprises a plurality of groups of antenna arrays, and the antenna arrays are used for receiving signals. The N groups of antenna arrays may be all antenna arrays of the OPA lidar, or may be part of antenna arrays of the OPA lidar, which is not limited herein.
The OPA laser radar can emit detection signals to a target detection object, the target detection object can reflect echo signals to the OPA laser radar based on the detection signals, and the OPA laser radar can receive the echo signals through N groups of antenna arrays at the same time to obtain N echo signals. Each group of antenna arrays corresponds to one echo signal, so that N groups of antenna arrays correspond to N echo signals.
According to the multi-group antenna array structure based on the OPA laser radar, N echo signals can be obtained rapidly in a one-shot and multi-shot (namely one-shot and multi-shot) mode (namely, one-shot detection signals are emitted and N echo signals are received simultaneously), and the scanning frequency of the OPA laser radar is not affected.
For the jth echo signal, the jth echo signal is any echo signal in the N echo signals, and the difference frequency signal corresponding to the jth echo signal can be obtained by mixing the jth echo signal with the current local oscillation signal.
For the ith difference frequency signal, the ith difference frequency signal is any one of N difference frequency signals, and the first frequency spectrum corresponding to the ith difference frequency signal can be obtained by performing fast Fourier transform on the ith difference frequency signal.
The step is the same as step 102, and the detailed description of step 102 is omitted here.
The step is the same as step 103, and specific reference may be made to the related description of step 103, which is not repeated here.
According to the embodiment, based on the first embodiment, the multiple groups of antenna array structures based on the OPA laser radar can quickly obtain N echo signals without affecting the scanning frequency of the OPA laser radar.
Referring to fig. 4, a schematic implementation flow chart of a signal enhancement method according to a third embodiment of the present application is provided, where the signal enhancement method is applied to OPA lidar. As shown in fig. 4, the signal enhancement method may include the steps of:
in step 401, a detection signal is transmitted to the target probe, where the detection signal is used to indicate that the target probe reflects an echo signal.
The target detection object may be a static object or a moving object, such as a vehicle, a pedestrian, an unmanned aerial vehicle, etc., and the specific type of the target detection object is not limited in the present application.
The OPA laser radar comprises a transmitting array, wherein the transmitting unit in the transmitting array is used for transmitting optical signals, and the optical signals can be divided into two paths of signals, namely local oscillation signals and detection signals after sequentially passing through an electro-optical modulator and a 1 multiplied by 2 beam splitter. The local oscillator signal is used for mixing.
The OPA lidar may transmit a detection signal to a target probe, which may reflect an echo signal to the OPA lidar based on the detection signal.
A single echo signal is acquired, step 402.
The OPA lidar comprises a plurality of sets of antenna arrays for receiving signals.
In this embodiment, the OPA lidar may receive echo signals through a set of antenna arrays to obtain a single echo signal.
Step 405 determines if the spectral amplitude of the first frequency spectrum is less than an amplitude threshold.
The intensity of the echo signal can be judged by judging whether the frequency spectrum amplitude of the first frequency spectrum is smaller than an amplitude threshold value; if the frequency spectrum amplitude of the first frequency spectrum is smaller than the amplitude threshold, judging that the intensity of the echo signal is weaker, and carrying out signal enhancement through the scheme of the application to improve the ranging capability of the OPA laser radar; if the spectrum amplitude of the first frequency spectrum is greater than or equal to the amplitude threshold, the intensity of the echo signal is determined to be strong, and the distance can be accurately measured according to the echo signal with the strong intensity without executing the scheme of the application. Wherein the amplitude threshold may be derived from an actual test. In some embodiments, the reasons for distance measurement, weak reflection surfaces, etc. may all result in weak echo signal strength.
In case the spectral amplitude of the first frequency spectrum is smaller than the amplitude threshold, N first frequency spectra may be obtained by performing steps 401 to 404N-1 times back.
In this embodiment, under the condition that the intensity of the echo signal is weak, based on the multi-group antenna array structure of the OPA laser radar, a single first frequency spectrum can be obtained by transmitting and receiving (i.e. transmitting a detection signal once and receiving a single echo signal), and N first frequency spectrums can be obtained by repeatedly executing N times of transmitting and receiving.
And repeatedly executing N times of sending and receiving, namely, transmitting N times of detection signals to the target detection object, and in order to reduce the measurement errors of the frequency and the distance, the detection points on the target detection object aimed by the N times of detection signals are required to be kept unchanged, namely, the points (namely, detection points) on the detected target detection object are the same when the OPA laser radar transmits the N times of detection signals.
Optionally, before determining whether the spectral amplitude of the first frequency spectrum is less than the amplitude threshold, the embodiment further includes:
comparing the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the first frequency spectrum to obtain a first maximum value, wherein the first maximum value is the maximum value in the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the first frequency spectrum;
the first maximum is determined as the spectral amplitude of the first frequency spectrum.
Wherein the first maximum is a peak of the first frequency spectrum. The signal intensity corresponding to the peak value of the first frequency spectrum is strongest, if the spectrum amplitude of the first frequency spectrum is smaller than the amplitude threshold value, the spectrum amplitudes corresponding to all spectrum serial numbers in the first frequency spectrum are smaller than the amplitude threshold value, which indicates that the intensity of the echo signal is weaker.
The step is partially the same as step 102, and the same parts are specifically referred to the relevant description of step 102, and are not repeated here.
The step is the same as step 103, and specific reference may be made to the related description of step 103, which is not repeated here.
In this embodiment, on the basis of the first embodiment, in the case that the intensity of the echo signal is weak, the multiple antenna array structures based on the OPA lidar may obtain N first frequency spectrums by repeatedly performing N times of transmission and reception. In addition, because the intensity of the echo signal is weaker, the signal-to-noise ratio of the echo signal is lower, and under the condition of low signal-to-noise ratio, the OPA laser radar can accurately measure the frequency of the difference frequency signal through the embodiment, so that the ranging capability of the OPA laser radar is improved.
Fig. 5 shows a block diagram of a signal enhancement device according to a fourth embodiment of the present application, which is applicable to OPA lidar, corresponding to the signal enhancement method of the above embodiment. For convenience of explanation, only portions relevant to the embodiments of the present application are shown.
The signal enhancement device includes:
the frequency spectrum acquisition module 51 is configured to acquire first frequency spectrums corresponding to N difference frequency signals of a target probe, where the first frequency spectrums include a spectrum sequence number and a spectrum amplitude corresponding to the spectrum sequence number, and N is an integer greater than 1;
the dot product operation module 52 is configured to perform dot product operation on the spectrum magnitudes with the same spectrum numbers in the N first frequencies to obtain a signal-to-noise ratio of
X is the second frequency spectrum of (2) 1 Signal-to-noise ratio for a single first frequency spectrum;
the frequency determining module 53 is configured to determine the frequency of the difference frequency signal according to the second frequency spectrum.
Optionally, the OPA lidar includes N antenna arrays, and the frequency spectrum acquisition module 51 is specifically configured to:
transmitting a detection signal to the target detection object once, wherein the detection signal is used for indicating the target detection object to reflect the echo signal;
acquiring echo signals received by N groups of antenna arrays at the same time to obtain N echo signals;
mixing N echo signals with the current local oscillation signal respectively to obtain difference frequency signals corresponding to the N echo signals;
and respectively performing fast Fourier transform on the N difference frequency signals to obtain first frequency spectrums corresponding to the N difference frequency signals.
Alternatively, the frequency spectrum acquisition module 51 is specifically configured to:
transmitting a detection signal to the target detection object once, wherein the detection signal is used for indicating the target detection object to reflect the echo signal;
acquiring a single echo signal;
mixing the echo signal with the current local oscillation signal to obtain a difference frequency signal corresponding to the echo signal;
performing fast Fourier transform on the difference frequency signal to obtain a first frequency spectrum corresponding to the difference frequency signal;
judging whether the spectrum amplitude of the first frequency spectrum is smaller than an amplitude threshold value;
if the spectrum amplitude of the first frequency spectrum is smaller than the amplitude threshold, the steps of transmitting a detection signal to a target detection object once, acquiring a single echo signal, mixing the echo signal with a current local oscillation signal to obtain a difference frequency signal, and performing fast Fourier transform on the difference frequency signal to obtain first frequency spectrums corresponding to the difference frequency signal until N first frequency spectrums are obtained.
Optionally, the detection point on the target probe for which the N detection signals are directed remains unchanged.
Optionally, the frequency spectrum acquisition module 51 is further configured to:
comparing the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the first frequency spectrum to obtain a first maximum value, wherein the first maximum value refers to the maximum value in the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the first frequency spectrum;
the first maximum is determined as the spectral amplitude of the first frequency spectrum.
Optionally, the difference frequency signal is determined by an echo signal reflected by the target probe, and the above-mentioned dot product operation module 52 is specifically configured to:
performing point multiplication operation on the spectrum amplitudes with the same spectrum sequence number in the N first frequency spectrums to obtain signal power of a second frequency spectrum;
determining the noise power of the second frequency spectrum according to the single noise power;
calculating the signal-to-noise ratio of the second frequency spectrum according to the signal power of the second frequency spectrum and the noise power of the second frequency spectrum;
wherein ,
x N for the signal-to-noise ratio of the second frequency spectrum, A 2N For the signal power of the second frequency spectrum, A is the amplitude of the echo signal, +.>
For noise power, sigma, of the second frequency spectrum 2 Is a single noise power.
Optionally, the frequency determining module 53 is specifically configured to:
comparing the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the second frequency spectrum to obtain a second maximum value, wherein the second maximum value is the maximum value in the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the second frequency spectrum;
and determining the frequency of the difference frequency signal according to the frequency spectrum sequence number corresponding to the second maximum value.
It should be noted that, because the content of information interaction and execution process between the above devices/units is based on the same concept as the method embodiment of the present application, specific functions and technical effects thereof may be referred to in the method embodiment section, and will not be described herein again.
Fig. 6 is a schematic structural diagram of an OPA lidar provided in a fifth embodiment of the present application. As shown in fig. 6, the OPA lidar 6 of this embodiment includes: one or more processors 60 (only one shown), a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. The steps of the various signal enhancement method embodiments described above are implemented by the processor 60 when executing the computer program 62.
The OPA lidar may include, but is not limited to, a processor 60, a memory 61. It will be appreciated by those skilled in the art that fig. 6 is merely an example of OPA lidar 6 and is not limiting of OPA lidar 6, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the OPA lidar may also include input and output devices, network access devices, buses, etc. Optionally, the OPA lidar further comprises an antenna array, a transmitting array, an electro-optic modulator, a beam splitter, etc.
The processor 60 may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 61 may be an internal storage unit of the OPA lidar 6, such as a hard disk or a memory of the OPA lidar 6. The memory 61 may be an external storage device of the OPA lidar 6, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided in the OPA lidar 6. Further, the memory 61 may also include both an internal memory unit and an external memory device of the OPA lidar 6. The memory 61 is used for storing the computer program and other programs and data required for the OPA lidar. The memory 61 may also be used for temporarily storing data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above device may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.
The embodiments of the present application also provide a computer readable storage medium storing a computer program, where the computer program when executed by a processor implements steps of the foregoing method embodiments.
Embodiments of the present application also provide a computer program product that, when run on an OPA lidar, causes the OPA lidar to perform steps that enable the implementation of the method embodiments described above.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in this application, it should be understood that the disclosed apparatus/OPA lidar and method may be implemented in other ways. For example, the above-described apparatus/OPA lidar embodiments are merely illustrative, e.g., the division of the modules or units is merely a logical functional division, and there may be additional divisions in actual implementation, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present application may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each method embodiment described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (10)
1. A signal enhancement method for use with OPA lidar, the signal enhancement method comprising:
acquiring first frequency spectrums corresponding to N difference frequency signals of a target detection object, wherein the first frequency spectrums comprise frequency spectrum serial numbers and frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers, and N is an integer greater than 1;
performing point multiplication operation on the N spectrum amplitudes with the same spectrum sequence number in the first frequency to obtain a signal-to-noise ratio of
X is the second frequency spectrum of (2) 1 Signal to noise ratio for a single said first frequency spectrum;
and determining the frequency of the difference frequency signal according to the second frequency spectrum.
2. The method of signal enhancement according to claim 1, wherein the OPA lidar includes N sets of antenna arrays, and the acquiring first frequency spectrums corresponding to each of the N difference frequency signals for the target probe includes:
transmitting a detection signal to the target detection object once, wherein the detection signal is used for indicating the target detection object to reflect an echo signal;
acquiring N groups of echo signals received by the antenna array at the same time to obtain N echo signals;
mixing N echo signals with a current local oscillation signal respectively to obtain difference frequency signals corresponding to the N echo signals;
and respectively performing fast Fourier transform on the N difference frequency signals to obtain first frequency spectrums corresponding to the N difference frequency signals.
3. The signal enhancement method of claim 1, wherein the acquiring the first frequency spectrum corresponding to each of the N difference frequency signals for the target probe comprises:
transmitting a detection signal to the target detection object once, wherein the detection signal is used for indicating the target detection object to reflect an echo signal;
acquiring a single echo signal;
mixing the echo signal with a current local oscillation signal to obtain a difference frequency signal corresponding to the echo signal;
performing fast Fourier transform on the difference frequency signal to obtain a first frequency spectrum corresponding to the difference frequency signal;
judging whether the spectrum amplitude of the first frequency spectrum is smaller than an amplitude threshold value;
and if the frequency spectrum amplitude of the first frequency spectrum is smaller than the amplitude threshold, returning to execute the steps of transmitting a detection signal to the target detection object once, acquiring a single echo signal, mixing the echo signal with a current local oscillation signal to obtain a difference frequency signal, and performing fast Fourier transform on the difference frequency signal to obtain first frequency spectrums corresponding to the difference frequency signal until N first frequency spectrums are obtained.
4. A signal enhancement method according to claim 3, wherein the detection point on the target probe for which the detection signal is directed N times remains unchanged.
5. The signal enhancement method of claim 3, further comprising, prior to determining whether the spectral amplitude of the first frequency spectrum is less than an amplitude threshold:
comparing the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the first frequency spectrum to obtain a first maximum value, wherein the first maximum value is the maximum value in the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the first frequency spectrum;
a first maximum is determined as a spectral amplitude of the first frequency spectrum.
6. The signal enhancement method according to any one of claims 1 to 5, wherein said difference frequency signal is determined from echo signals reflected from said target probe, said first N firstPerforming point multiplication operation on the spectrum amplitudes with the same spectrum sequence number in the frequency spectrum to obtain a signal-to-noise ratio of
Comprises:
performing point multiplication operation on the spectrum amplitudes with the same spectrum sequence number in the N first frequency spectrums to obtain signal power of the second frequency spectrums;
determining the noise power of the second frequency spectrum according to the single noise power;
calculating the signal-to-noise ratio of the second frequency spectrum according to the signal power of the second frequency spectrum and the noise power of the second frequency spectrum;
wherein ,
x N for the signal-to-noise ratio of the second frequency spectrum, A 2N For the signal power of the second frequency spectrum, A is the amplitude of the echo signal, +.>
Sigma for the noise power of the second frequency spectrum 2 Is a single noise power.
7. The signal enhancement method according to any one of claims 1 to 5, wherein said determining the frequency of the difference frequency signal from the second frequency spectrum comprises:
comparing the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the second frequency spectrum to obtain a second maximum value, wherein the second maximum value is the maximum value in the frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers in the second frequency spectrum;
and determining the frequency of the difference frequency signal according to the frequency spectrum sequence number corresponding to the second maximum value.
8. A signal enhancement device for use with an OPA lidar, the signal enhancement device comprising:
the frequency spectrum acquisition module is used for acquiring first frequency spectrums corresponding to N difference frequency signals of a target detection object, wherein the first frequency spectrums comprise frequency spectrum serial numbers and frequency spectrum amplitudes corresponding to the frequency spectrum serial numbers, and N is an integer larger than 1;
the point multiplication operation module is used for carrying out point multiplication operation on the N frequency spectrum amplitudes with the same frequency spectrum sequence number in the first frequency spectrum to obtain a signal to noise ratio of
X is the second frequency spectrum of (2) 1 Signal to noise ratio for a single said first frequency spectrum;
and the frequency determining module is used for determining the frequency of the difference frequency signal according to the second frequency spectrum.
9. OPA lidar comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the signal enhancement method according to any of claims 1 to 7 when the computer program is executed by the processor.
10. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the signal enhancement method according to any one of claims 1 to 7.
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| CN202111544889.6A CN116265982A (en) | 2021-12-16 | 2021-12-16 | Signal enhancement method and device, OPA laser radar and storage medium |
| PCT/CN2022/130634 WO2023109375A1 (en) | 2021-12-16 | 2022-11-08 | Signal enhancement method and apparatus, opa lidar, and storage medium |
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