CN111239705B - Signal processing method, device and equipment of laser radar and storage medium - Google Patents
Signal processing method, device and equipment of laser radar and storage medium Download PDFInfo
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Abstract
The application provides a signal processing method, a signal processing device, signal processing equipment and a signal processing storage medium of a laser radar, and relates to the technical field of laser radars. The method comprises the following steps: obtaining a reflection echo of a target object detected by the laser radar, and performing Fourier transform on the reflection echo to obtain a frequency spectrum signal corresponding to the reflection echo, wherein the frequency spectrum signal comprises: a plurality of subcarriers; optimizing each subcarrier according to a preset frequency spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier; performing inverse Fourier transform on the optimized spectrum signals of the plurality of subcarriers to obtain a transformed time domain waveform; and processing the time domain waveform after the transformation by adopting a preset time domain waveform matching algorithm and a preset interpolation algorithm in sequence to obtain the distance between the laser radar and the target object. Compared with the prior art, the problem that the range and the imaging distance of the laser radar are too close in the prior art is solved.
Description
Technical Field
The present application relates to the field of laser radar technology, and in particular, to a method, an apparatus, a device, and a storage medium for processing a laser radar signal.
Background
The vehicle-mounted laser radar is regarded as the most key component in the perception stage of automatic driving due to the ultrahigh distance resolution and spatial resolution capability of the vehicle-mounted laser radar. The range, spatial resolution and dot frequency are the most important performance indexes of the laser radar.
In the prior art, a receiving end architecture and a signal processing part of a laser radar are provided. The reflected echo of the target object enters a signal processing unit for ranging through photoelectric conversion, circuit amplification, filtering conditioning and analog-to-digital conversion, and the distance of the target object to be measured can be obtained after the reflected echo is processed. In order to adapt to the application scenario of medium-high speed automatic driving, the lidar needs to have a longer ranging range.
However, in such a laser radar, when the target object is far away from the target object and the reflectivity of the target object is low, the echo signal is weakened and the corresponding amplitude is reduced, so that the echo signal is easily unrecognizable, and the laser radar cannot detect the target object, and the ranging range is limited.
Disclosure of Invention
An object of the present application is to provide a method, an apparatus, a device, and a storage medium for processing a signal of a laser radar, so as to solve the problem that the range and the imaging distance of the laser radar are too short in the prior art.
In order to achieve the above purpose, the technical solutions adopted in the embodiments of the present application are as follows:
in a first aspect, an embodiment of the present application provides a signal processing method for a laser radar, where the method includes:
acquiring a reflected echo of a target object detected by the laser radar, wherein the reflected echo is a time domain signal;
performing Fourier transform on the reflected echo to obtain a spectrum signal corresponding to the reflected echo, wherein the spectrum signal comprises: a plurality of subcarriers;
optimizing each subcarrier according to a preset frequency spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier; the larger the signal-to-noise ratio of the subcarriers, the larger the corresponding preset spectrum optimization coefficient;
performing inverse Fourier transform on the optimized spectrum signals of the plurality of subcarriers to obtain a transformed time domain waveform;
and processing the time domain waveform after the transformation by adopting a preset time domain waveform matching algorithm and a preset interpolation algorithm in sequence to obtain the distance between the laser radar and the target object.
Optionally, the optimizing the amplitude of each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain the optimized each subcarrier includes:
And optimizing each subcarrier according to the product of the preset spectrum optimization coefficient corresponding to each subcarrier and the amplitude of each subcarrier to obtain each optimized subcarrier, wherein the amplitude of each optimized subcarrier is the amplitude after the product.
Optionally, before optimizing each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier, the method further includes:
and determining a preset frequency spectrum optimization coefficient corresponding to the frequency of each subcarrier as a preset frequency spectrum optimization coefficient corresponding to each subcarrier according to the frequency of each subcarrier and the corresponding relation between a preset carrier frequency and the frequency spectrum optimization coefficient.
Optionally, before optimizing each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier, the method further includes:
determining a signal-to-noise ratio of each subcarrier;
and calculating a preset spectrum optimization coefficient corresponding to each subcarrier according to the signal-to-noise ratio of each subcarrier.
Optionally, the determining the signal-to-noise ratio of each subcarrier includes:
Separating signals and noise from the reflected echo to obtain a separated signal waveform and a separated noise waveform;
respectively carrying out Fourier transform on the separated signal waveform and the noise waveform to obtain a transformed signal frequency spectrum and a transformed noise frequency spectrum;
and calculating the signal-to-noise ratio of each subcarrier according to the transformed signal spectrum and the transformed noise spectrum.
Optionally, before the separation of the signal and the noise of the reflected echo is performed to obtain a separated signal waveform and a separated noise waveform, the method further includes:
judging whether the amplitude of the reflected echo is greater than or equal to a preset threshold value or not;
the separation of the signal and the noise of the reflected echo is carried out to obtain a separated signal waveform and a separated noise waveform, and the separation comprises the following steps:
and if the amplitude of the reflected echo is greater than or equal to the preset threshold, separating the signal and the noise of the reflected echo to obtain the separated signal frequency spectrum and the separated noise frequency spectrum.
Optionally, the method further comprises: and storing the corresponding relation between the frequency of each subcarrier and the preset frequency spectrum optimization coefficient corresponding to each subcarrier.
In a second aspect, another embodiment of the present application provides a signal processing apparatus for a lidar, the apparatus including: the device comprises an acquisition module, a transformation module, an optimization module and a processing module, wherein:
the acquisition module is used for acquiring a reflected echo of a target object detected by the laser radar, wherein the reflected echo is a time domain signal;
the transform module is configured to perform fourier transform on the reflected echo to obtain a spectrum signal corresponding to the reflected echo, where the spectrum signal includes: a plurality of subcarriers;
the optimization module is configured to optimize each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier; the larger the signal-to-noise ratio of the subcarriers, the larger the corresponding preset spectrum optimization coefficient;
the transform module is further configured to perform inverse fourier transform on the optimized spectrum signals of the multiple subcarriers to obtain a transformed time domain waveform;
and the processing module is used for sequentially adopting a preset time domain waveform matching algorithm and a preset interpolation algorithm to process according to the transformed time domain waveform to obtain the distance between the laser radar and the target object.
Optionally, the optimizing module is further configured to optimize each subcarrier according to a product of a preset spectrum optimization coefficient corresponding to each subcarrier and the amplitude of each subcarrier, so as to obtain each optimized subcarrier, where the amplitude of each optimized subcarrier is the amplitude after the product.
Optionally, the apparatus further comprises: and the determining module is used for determining the preset frequency spectrum optimization coefficient corresponding to the frequency of each subcarrier as the preset frequency spectrum optimization coefficient corresponding to each subcarrier according to the frequency of each subcarrier and the corresponding relation between the preset carrier frequency and the frequency spectrum optimization coefficient.
Optionally, the apparatus further comprises: a computing module, wherein:
the determining module is further configured to determine a signal-to-noise ratio of each subcarrier;
and the calculating module is used for calculating a preset spectrum optimization coefficient corresponding to each subcarrier according to the signal-to-noise ratio of each subcarrier.
Optionally, the apparatus further comprises: the separation module is used for separating signals and noise of the reflected echo to obtain a separated signal waveform and a separated noise waveform;
the transform module is further configured to perform fourier transform on the separated signal waveform and the noise waveform respectively to obtain a transformed signal spectrum and a transformed noise spectrum;
The calculating module is further configured to calculate a signal-to-noise ratio of each subcarrier according to the transformed signal spectrum and the transformed noise spectrum.
Optionally, the apparatus further comprises: the judging module is used for judging whether the amplitude of the reflected echo is greater than or equal to a preset threshold value or not;
the separation module is further configured to separate a signal from a noise of the reflected echo if the amplitude of the reflected echo is greater than or equal to the preset threshold, so as to obtain the separated signal spectrum and the separated noise spectrum.
In a third aspect, another embodiment of the present application provides a signal processing apparatus for a lidar, including: a processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, the processor and the storage medium communicate via the bus when a signal processing device of the lidar is operated, and the processor executes the machine-readable instructions to perform the steps of the method according to any one of the first aspect.
In a fourth aspect, another embodiment of the present application provides a storage medium having a computer program stored thereon, where the computer program is executed by a processor to perform the steps of the method according to any one of the above first aspects.
The beneficial effect of this application is: according to the signal processing method of the laser radar, after Fourier transformation is carried out on reflection echoes, each subcarrier of a spectrum signal corresponding to the obtained reflection echoes is optimized according to a corresponding preset spectrum optimization coefficient, each subcarrier is optimized, each optimized subcarrier is obtained, inverse Fourier transformation is carried out on the spectrum signals of a plurality of optimized subcarriers, then according to a time domain waveform after transformation, a preset time domain waveform matching algorithm and a preset interpolation algorithm are adopted in sequence for processing, and the distance between the laser radar and a target object is obtained. Due to the fact that the received reflection echo is optimized, the effective signal can be recovered under the condition that the reflection echo signal is submerged by noise or interference, and therefore the ranging range of the laser radar is prolonged.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a schematic flowchart of a signal processing method of a laser radar according to an embodiment of the present disclosure;
fig. 2 is a schematic flowchart of a process of acquiring a reflected echo by a laser radar according to an embodiment of the present disclosure;
fig. 3 is a schematic flowchart of a signal processing method of a laser radar according to another embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of a signal processing apparatus of a laser radar according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of a signal processing apparatus of a lidar according to another embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of a signal processing apparatus of a lidar according to another embodiment of the present application;
fig. 7 is a schematic structural diagram of a signal processing apparatus of a lidar according to another embodiment of the present application;
fig. 8 is a schematic structural diagram of a signal processing apparatus of a laser radar according to another embodiment of the present application;
fig. 9 is a schematic structural diagram of a signal processing apparatus of a laser radar according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments.
Fig. 1 is a schematic flowchart of a signal processing method for a lidar according to an embodiment of the present disclosure, where the lidar includes a lidar detector and a processor. The method may be performed by a processor of the lidar and may also be performed by a processing device coupled to the lidar. As shown in fig. 1, the method includes:
s101: and acquiring the reflected echo of the target object detected by the laser radar.
The method can obtain the reflected echo of the target object detected by the laser radar detector in the laser radar. The laser radar further comprises: and the laser transmitter is used for transmitting a laser signal, and the target object can reflect the laser signal after receiving the laser signal so as to obtain a reflected echo.
Illustratively, the lidar detector may include a photodetector. The reflected echo is a time domain signal. Fig. 2 is a schematic flow chart of a process for acquiring a reflected echo by an inner processor of a laser radar according to an embodiment of the present disclosure, as shown in fig. 2, a photodetector 201 of the laser radar may receive an optical echo signal reflected by a target object, amplify the received optical echo signal by an amplifier 202, transmit the amplified optical echo signal to a filter circuit 203, filter the amplified optical echo signal by the filter circuit 203, perform digital-to-analog conversion by a digital-to-analog converter 204 to obtain a reflected echo, and transmit the reflected echo to a processor 205.
S102: and carrying out Fourier transform on the reflected echo to obtain a frequency spectrum signal corresponding to the reflected echo.
Wherein the spectrum signal comprises: a plurality of subcarriers, each subcarrier corresponding to a frequency. In an embodiment of the present application, the Fourier transform may be implemented by selecting a Fast Fourier Transform (FFT), but a specific selection of the Fourier transform may be designed according to a user requirement, and is not limited to the above embodiment. The received reflection echoes are denoted by x (n), and n is the time number 1, 2, 3 … of the sampling point. The spectrum signal corresponding to each reflected echo after FFT can be expressed as follows:
S103: and optimizing each subcarrier according to the preset frequency spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier.
In an embodiment of the present application, the criterion of the preset spectrum optimization coefficient is a subcarrier signal-to-noise ratio criterion, that is, in a plurality of subcarriers, the subcarrier with a larger signal-to-noise ratio has a larger corresponding preset spectrum optimization coefficient, so as to enhance a signal; the smaller the signal-to-noise ratio of the sub-carrier is, the smaller the corresponding preset spectrum optimization coefficient is, so as to suppress noise and interference, and such optimization setting can achieve the effects of enhancing signals and suppressing noise and interference.
In particular implementations, optimizing each subcarrier may include optimizing the amplitude of each subcarrier.
S104: and performing inverse Fourier transform on the optimized spectrum signals of the plurality of subcarriers to obtain a transformed time domain waveform.
In an embodiment of the present application, the inverse fourier transform is implemented by fast inverse fourier transform (IFFT), but may be other inverse fourier transforms, which is specifically determined by the fourier transform employed in S102. Note that the inverse fourier transform used in S104 may be an inverse fourier transform corresponding to the fourier transform used in S102. The optimized spectrum signals of the multiple subcarriers can be represented as y (k), and the time domain waveform after IFFT can be represented as follows:
Where N is the IFFT length, and is equal to the FFT length in S102; and y (n) is a transformed time domain waveform corresponding to the frequency spectrum signal and is a real number.
S105: and processing the time domain waveform according to the transformed time domain waveform by adopting a preset time domain waveform matching algorithm and a preset interpolation algorithm in sequence to obtain the distance between the laser radar and the target object.
The method comprises the steps of firstly finding effective echo signals in a transformed time domain waveform according to a time domain waveform matching algorithm, then extracting flight time and distance by using an interpolation algorithm, and then calculating to obtain the distance between a target object to be measured and a laser radar by using a preset distance measuring algorithm to realize distance measurement of the target object.
The time domain waveform matching algorithm is to process the transformed time domain waveform, find the pulse with the maximum amplitude in the time domain waveform, and compare the pulse with the maximum amplitude with the transmitted pulse, thereby extracting an effective echo signal. The interpolation algorithm is to process the waveform of the extracted effective echo signal and interpolate between adjacent sampling points to obtain higher time resolution, and finally obtain the distance between the target object to be measured and the laser radar.
By adopting the signal processing method of the laser radar, after Fourier transformation is carried out on the reflection echo, each subcarrier of the frequency spectrum signal corresponding to the obtained reflection echo is optimized according to the corresponding preset frequency spectrum optimization coefficient, each subcarrier is optimized, each optimized subcarrier is obtained, inverse Fourier transformation is carried out on the frequency spectrum signals of a plurality of optimized subcarriers, and then according to the time domain waveform after transformation, the preset time domain waveform matching algorithm and the preset interpolation algorithm are adopted in sequence for processing, so that the distance between the laser radar and the target object is obtained. The processing mode optimizes the received reflection echo, enhances signals, inhibits noise and interference and the like, so that effective signals can be recovered under the condition that the reflection echo signals are submerged by the noise or the interference, and the ranging range of the laser radar is prolonged.
On the basis of the signal processing method of the laser radar shown in fig. 1, an implementation example of the signal processing method of the laser radar may also be provided in the embodiments of the present application. Fig. 3 is a schematic flowchart of a signal processing method of a lidar according to another embodiment of the present disclosure, and as shown in fig. 3, S103 may include:
s106: and optimizing each subcarrier according to the product of the preset spectrum optimization coefficient corresponding to each subcarrier and the amplitude of each subcarrier to obtain each optimized subcarrier.
In an implementation process, the following formula may be used to optimize each subcarrier according to a preset spectrum optimization coefficient as follows:
Y(k)＝X(k)·c(k)
wherein, c (k) is a spectrum optimization coefficient, which is a group of complex numbers, each subcarrier corresponds to a spectrum optimization coefficient, and the spectrum optimization coefficients of the subcarriers may be the same and may be different; y (k) is each subcarrier after optimization.
Optionally, in an embodiment of the present application, the obtaining manner of the preset spectrum optimization coefficient may include the following two possible implementation manners:
the first method is as follows: and determining a preset frequency spectrum optimization coefficient corresponding to the frequency of each subcarrier as a preset frequency spectrum optimization coefficient corresponding to each subcarrier according to the frequency of each subcarrier and the corresponding relation between the preset carrier frequency and the frequency spectrum optimization coefficient.
In this way, the spectral optimization coefficients are measured in advance, and only when the subcarriers are optimized, the corresponding spectral optimization coefficients are read based on the frequencies of the subcarriers. In an embodiment of the present application, the lidar further includes a memory, and the spectrum optimization coefficients and the corresponding relationship between the preset carrier frequency and the spectrum optimization coefficients are stored in an internal memory of the lidar. Of course, it may also be stored in an external memory, which is not limited by this application. The processor of the laser radar or the processing device connected with the laser radar can acquire the preset frequency spectrum optimization coefficient corresponding to the current subcarrier frequency in the preset memory according to the corresponding relation between the preset carrier frequency and the frequency spectrum optimization coefficient after acquiring the frequency of each subcarrier.
The second method comprises the following steps: determining a signal-to-noise ratio of each subcarrier; and calculating a preset spectrum optimization coefficient corresponding to each subcarrier according to the signal-to-noise ratio of each subcarrier.
That is, in this mode, the preset spectral optimization coefficients are calculated from the time domain waveform. In one embodiment of the application, the calculation may be performed by a processor or processing device executing the signal processing method. After the time domain waveform corresponding to each subcarrier is obtained, judging whether signals and noise of the time domain waveform can be separated or not, if so, respectively carrying out Fourier transform on the signal waveform and the noise waveform, then calculating the signal-to-noise ratio of the subcarrier, and finally calculating the frequency spectrum optimization coefficient corresponding to the subcarrier according to the signal-to-noise ratio of the subcarrier; if the signals and the noise of the time domain waveform can not be separated by judgment, the frequency spectrum optimization coefficient of the current time domain waveform is delayed by the frequency spectrum optimization coefficient of the previous period, namely the frequency spectrum optimization coefficient of the current time domain waveform is consistent with the frequency spectrum optimization coefficient of the previous period, the current time domain waveform is directly optimized according to the frequency spectrum optimization coefficient, and calculation is not carried out.
After time domain waveforms corresponding to other subcarriers are subsequently obtained, firstly, whether the peak value of the time domain waveform is larger than a preset threshold value or not is judged, if the peak value of the time domain waveform is smaller than the preset threshold value, the frequency spectrum optimization coefficient does not need to be recalculated, and the frequency spectrum optimization coefficient calculated last time is directly used; if the signal waveform is larger than the preset value, judging whether the signal and the noise of the time domain waveform can be separated, if so, respectively carrying out Fourier transform on the signal waveform and the noise waveform, then calculating the signal-to-noise ratio of the subcarrier, and finally calculating the frequency spectrum optimization coefficient corresponding to the subcarrier according to the signal-to-noise ratio of the subcarrier.
In an embodiment of the present application, each spectrum optimization coefficient obtained through calculation in the second mode may be further stored according to a frequency of each subcarrier and a corresponding relationship between preset spectrum optimization coefficients corresponding to each subcarrier, so that when the apparatus is used next time, the processor or the processing device may directly obtain the preset spectrum optimization coefficient corresponding to the current subcarrier from the memory according to the corresponding relationship between the subcarrier and the preset spectrum optimization coefficients.
By adopting the signal processing of the laser radar provided by the application, the received waveform of the reflected echo is accurately converted to the frequency spectrum signal by adding the frequency spectrum optimization processing step on the basis of the signal processing of the existing laser radar, then the frequency spectrum signal is divided into a plurality of subcarriers by the frequency spectrum optimization algorithm, and each subcarrier is optimized, so that the signal-to-noise ratio of the whole frequency spectrum signal is optimized, and the effects of reconstructing and recovering echo pulse signals and suppressing noise interference are achieved.
Compared with the prior art, the method provided by the application has the advantages that when the signal amplitude of the reflection echo of the target object is smaller than the maximum amplitude of the noise and the interference (namely the signal is submerged by the noise and the interference), the signal amplitude of the reflection echo is strengthened and the noise and the interference are weakened through frequency spectrum optimization processing, and therefore the method provided by the application can be suitable for a laser radar system working in a long distance.
Meanwhile, as the spectrum line of the periodic interference is narrow, the frequency domain optimization algorithm based on the multiple subcarriers can effectively inhibit the interference, namely the method provided by the application has strong capability of resisting the periodic interference such as circuit control signal crosstalk or circuit oscillation interference and the like, and ensures that the signal amplitude is not influenced. The laser radar signal processing method can effectively prolong the ranging range of the laser radar and provide reliable detection data and imaging images for medium-high speed automatic driving automobiles or robots and the like.
Fig. 4 is a schematic structural diagram of a signal processing apparatus of a laser radar according to an embodiment of the present application, and as shown in fig. 4, the apparatus includes: an obtaining module 301, a transforming module 302, an optimizing module 303 and a processing module 304, wherein:
The obtaining module 301 is configured to obtain a reflected echo of a target object detected by a laser radar, where the reflected echo is a time domain signal.
A transform module 302, configured to perform fourier transform on the reflected echo to obtain a spectrum signal corresponding to the reflected echo, where the spectrum signal includes: a plurality of subcarriers.
The optimizing module 303 is configured to optimize each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier; in the multiple subcarriers, the larger the signal-to-noise ratio is, the larger the corresponding preset spectrum optimization coefficient is.
The transform module 302 is further configured to perform inverse fourier transform on the optimized spectrum signals of the multiple subcarriers, so as to obtain a transformed time domain waveform.
And the processing module 304 is configured to sequentially perform processing by using a preset time domain waveform matching algorithm and a preset interpolation algorithm according to the transformed time domain waveform, so as to obtain a distance between the laser radar and the target object.
Optionally, the optimizing module 303 is further configured to optimize each subcarrier according to a product of a preset spectrum optimization coefficient corresponding to each subcarrier and an amplitude of each subcarrier, to obtain each optimized subcarrier, where the amplitude of each optimized subcarrier is an amplitude after the product.
Fig. 5 is a schematic structural diagram of a signal processing apparatus of a lidar according to another embodiment of the present application, where as shown in fig. 5, the apparatus further includes: the determining module 305 is configured to determine, according to the frequency of each subcarrier and a corresponding relationship between a preset carrier frequency and a spectrum optimization coefficient, that a preset spectrum optimization coefficient corresponding to the frequency of each subcarrier is a preset spectrum optimization coefficient corresponding to each subcarrier.
Fig. 6 is a schematic structural diagram of a signal processing apparatus of a lidar according to another embodiment of the present application, where as shown in fig. 6, the apparatus further includes: a calculation module 306, wherein:
a determining module 305, further configured to determine a signal-to-noise ratio of each subcarrier;
a calculating module 306, configured to calculate a preset spectrum optimization coefficient corresponding to each subcarrier according to the signal-to-noise ratio of each subcarrier.
Fig. 7 is a schematic structural diagram of a signal processing apparatus of a laser radar according to another embodiment of the present application, and as shown in fig. 7, the apparatus further includes: a separation module 307, configured to separate signals and noise from the reflected echoes to obtain separated signal waveforms and noise waveforms;
the transform module 302 is further configured to perform fourier transform on the separated signal waveform and noise waveform respectively to obtain a transformed signal spectrum and a transformed noise spectrum;
The calculating module 306 is further configured to calculate a signal-to-noise ratio of each subcarrier according to the transformed signal spectrum and the transformed noise spectrum.
Fig. 8 is a schematic structural diagram of a signal processing apparatus of a lidar according to another embodiment of the present application, where as shown in fig. 8, the apparatus further includes: the judging module 308 is configured to judge whether the amplitude of the reflected echo is greater than or equal to a preset threshold;
the separation module 307 is further configured to separate a signal from noise of the reflected echo if the amplitude of the reflected echo is greater than or equal to a preset threshold, so as to obtain a separated signal spectrum and a separated noise spectrum.
The above-mentioned apparatus is used for executing the method provided by the foregoing embodiment, and the implementation principle and technical effect are similar, which are not described herein again.
These above modules may be one or more integrated circuits configured to implement the above methods, such as: one or more Application Specific Integrated Circuits (ASICs), or one or more microprocessors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), among others. For another example, when one of the above modules is implemented in the form of a Processing element scheduler code, the Processing element may be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. For another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).
Fig. 9 is a schematic structural diagram of a signal processing device of a lidar according to an embodiment of the present disclosure, where the signal processing device of the lidar may be integrated in an internal processor of the lidar or a chip of the processing device connected to the lidar.
The signal processing apparatus of the laser radar includes: a processor 501, a storage medium 502, and a bus 503.
The processor 501 is used for storing a program, and the processor 501 calls the program stored in the storage medium 502 to execute the method embodiment corresponding to fig. 1-3. The specific implementation and technical effects are similar, and are not described herein again.
Optionally, the present application also provides a program product, such as a storage medium, on which a computer program is stored, including a program, which, when executed by a processor, performs embodiments corresponding to the above-described method.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in the form of hardware, or in the form of hardware plus a software functional unit.
The integrated unit implemented in the form of a software functional unit may be stored in a computer-readable storage medium. The software functional unit is stored in a storage medium and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) or a processor (processor) to perform some steps of the methods according to the embodiments of the present application. And the aforementioned storage medium includes: a U disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Claims (7)
1. A method for signal processing of a lidar, the method comprising:
acquiring a reflected echo of a target object detected by the laser radar, wherein the reflected echo is a time domain signal;
performing Fourier transform on the reflected echo to obtain a spectrum signal corresponding to the reflected echo, wherein the spectrum signal comprises: a plurality of subcarriers;
optimizing each subcarrier according to a preset frequency spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier; the larger the signal-to-noise ratio of the subcarriers, the larger the corresponding preset spectrum optimization coefficient;
the optimizing the amplitude of each subcarrier according to the preset spectrum optimization coefficient corresponding to each subcarrier to obtain the optimized each subcarrier includes:
optimizing each subcarrier according to the product of the preset spectrum optimization coefficient corresponding to each subcarrier and the amplitude of each subcarrier to obtain each optimized subcarrier, wherein the amplitude of each optimized subcarrier is the amplitude after the product;
before optimizing each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier, the method further includes:
Determining a signal-to-noise ratio of each subcarrier; calculating a preset spectrum optimization coefficient corresponding to each subcarrier according to the signal-to-noise ratio of each subcarrier;
the determining the signal-to-noise ratio of each subcarrier includes:
separating signals and noise from the reflected echo to obtain a separated signal waveform and a separated noise waveform; respectively carrying out Fourier transform on the separated signal waveform and the noise waveform to obtain a transformed signal frequency spectrum and a transformed noise frequency spectrum; calculating the signal-to-noise ratio of each subcarrier according to the transformed signal spectrum and the transformed noise spectrum;
performing inverse Fourier transform on the optimized spectrum signals of the plurality of subcarriers to obtain a transformed time domain waveform;
and processing the time domain waveform after the transformation by adopting a preset time domain waveform matching algorithm and a preset interpolation algorithm in sequence to obtain the distance between the laser radar and the target object.
2. The method according to claim 1, wherein before optimizing each subcarrier according to a preset spectral optimization coefficient corresponding to each subcarrier to obtain the optimized each subcarrier, the method further comprises:
And determining a preset frequency spectrum optimization coefficient corresponding to the frequency of each subcarrier as a preset frequency spectrum optimization coefficient corresponding to each subcarrier according to the frequency of each subcarrier and the corresponding relation between a preset carrier frequency and the frequency spectrum optimization coefficient.
3. The method of claim 1, wherein before the separating the signal and the noise of the reflected echo to obtain the separated signal waveform and the noise waveform, the method further comprises:
judging whether the amplitude of the reflected echo is greater than or equal to a preset threshold value or not;
the separation of the signal and the noise of the reflected echo is carried out to obtain a separated signal waveform and a separated noise waveform, and the separation comprises the following steps:
and if the amplitude of the reflected echo is greater than or equal to the preset threshold, separating a signal from noise of the reflected echo to obtain the separated signal frequency spectrum and the separated noise frequency spectrum.
4. The method of claim 1, further comprising:
and storing the corresponding relation between the frequency of each subcarrier and the preset spectrum optimization coefficient corresponding to each subcarrier.
5. A signal processing apparatus of a laser radar, characterized in that the apparatus comprises: the device comprises an acquisition module, a transformation module, an optimization module and a processing module, wherein:
The acquisition module is used for acquiring a reflected echo of a target object detected by the laser radar, wherein the reflected echo is a time domain signal;
the transform module is configured to perform fourier transform on the reflected echo to obtain a spectrum signal corresponding to the reflected echo, where the spectrum signal includes: a plurality of subcarriers;
the optimization module is configured to optimize each subcarrier according to a preset spectrum optimization coefficient corresponding to each subcarrier to obtain each optimized subcarrier; the larger the signal-to-noise ratio of the subcarriers, the larger the corresponding preset spectrum optimization coefficient;
the optimization module is further specifically configured to optimize each subcarrier according to a product of a preset spectrum optimization coefficient corresponding to each subcarrier and an amplitude of each subcarrier, so as to obtain each optimized subcarrier, where the amplitude of each optimized subcarrier is the amplitude after the product;
the transform module is further configured to perform inverse fourier transform on the optimized spectrum signals of the multiple subcarriers to obtain a transformed time domain waveform;
the processing module is used for sequentially adopting a preset time domain waveform matching algorithm and a preset interpolation algorithm to process according to the transformed time domain waveform to obtain the distance between the laser radar and the target object;
The device further comprises: a calculation module and a separation module;
the calculating module is used for calculating a preset spectrum optimization coefficient corresponding to each subcarrier according to the signal-to-noise ratio of each subcarrier;
the separation module is used for separating signals and noise of the reflected echo to obtain a separated signal waveform and a separated noise waveform;
the transform module is further configured to perform fourier transform on the separated signal waveform and the noise waveform respectively to obtain a transformed signal spectrum and a transformed noise spectrum;
the calculating module is further configured to calculate a signal-to-noise ratio of each subcarrier according to the transformed signal spectrum and the transformed noise spectrum.
6. A signal processing apparatus of a laser radar, characterized by comprising: a processor, a storage medium and a bus, the storage medium storing machine-readable instructions executable by the processor, the processor and the storage medium communicating via the bus when a signal processing device of the lidar is operating, the processor executing the machine-readable instructions to perform the method of any of claims 1-4.
7. A storage medium, characterized in that the storage medium has stored thereon a computer program which, when being executed by a processor, carries out the method according to any one of the preceding claims 1-4.
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