阅读说明：本技术 一种基于毫米波设备的多目标跟踪方法及系统 (Multi-target tracking method and system based on millimeter wave equipment ) 是由 杨铮 张桂栋 于 2020-12-09 设计创作，主要内容包括：本发明实施例提供一种基于毫米波设备的多目标跟踪方法及系统,该方法包括：基于毫米波雷达的天线对应的线性调频信号,获取归一化后的距离速度谱；基于归一化后的距离速度谱,若判断获知监控区域中存在目标物体,获取目标物体的最终运动轨迹；根据天线对应的初始相位,获取目标物体对应的波达角；根据天线对应的初始相位,获取目标物体对应的波达角,并基于最终运动轨迹、目标物体的速度和波达角,对目标物体进行跟踪。本发明实施例基于毫米波雷达所获取的数据来对多个目标物体进行高精度追踪,利用毫米波波长短、分辨率高的优点,通过粒子滤波器进行数据的融合,并对多目标逐个进行追踪,从而实现长距离情况下多目标的高精度追踪系统。(The embodiment of the invention provides a multi-target tracking method and a system based on millimeter wave equipment, wherein the method comprises the following steps: acquiring a normalized distance velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar; based on the normalized distance velocity spectrum, if the target object in the monitoring area is judged and known to exist, the final motion track of the target object is obtained; acquiring a corresponding angle of arrival of a target object according to the initial phase corresponding to the antenna; and acquiring a corresponding arrival angle of the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle. The embodiment of the invention tracks a plurality of target objects with high precision based on the data acquired by the millimeter wave radar, fuses the data through the particle filter by utilizing the advantages of short millimeter wave wavelength and high resolution, and tracks a plurality of targets one by one, thereby realizing the high-precision tracking system of the plurality of targets under the long-distance condition.)

1. A multi-target tracking method based on millimeter wave equipment is characterized by comprising the following steps:

acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, wherein the distance and velocity spectrum represents the relation between the distance and the velocity in a monitoring area;

based on the normalized distance velocity spectrum, if the target object in the monitoring area is judged and known to exist, the final motion track of the target object is obtained;

acquiring a corresponding angle of arrival of the target object according to the initial phase corresponding to the antenna;

and acquiring a corresponding arrival angle of the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

2. The multi-target tracking method based on millimeter wave equipment according to claim 1, wherein the acquiring a final motion trajectory of the target object based on the normalized distance velocity spectrum if it is determined that the target object exists in the monitored area specifically comprises:

judging whether a target object exists in the monitoring area or not according to the normalized distance velocity spectrum;

if the target object in the monitoring area is judged and known to exist, all the target objects in the monitoring area are detected;

for a current target object, tracking the current target object through a preset particle filter algorithm based on the distance velocity spectrum, acquiring a motion track of the current target object, taking a next target object as the current target object again, eliminating the influence of the current target object in the distance velocity spectrum, taking the distance velocity spectrum without the influence as the distance velocity spectrum again, and repeatedly executing the step until the current target object is the last target object;

and taking the motion trail of the target object as the final motion trail.

3. The millimeter wave device-based multi-target tracking method according to claim 2, wherein the preset particle filtering algorithm is as follows:

particle initialization is performed after the target object has performed a start motion.

4. The millimeter wave device-based multi-target tracking method according to claim 2, wherein the step of taking the motion trail of the target object as the final motion trail further comprises:

for any two motion tracks, if the ending time of one motion track and the starting time of the other motion track are within a preset time error, and the ending position of one motion track and the starting position of the other motion track are within a preset distance error, combining the any two motion tracks into one motion track, and obtaining an optimized motion track corresponding to the target object;

and taking the optimized motion trail of the target object as the final motion trail again.

5. The multi-target tracking method based on millimeter wave devices according to any one of claims 1 to 4, wherein the step of taking the optimized motion trajectory of the target object as the final motion trajectory again comprises:

acquiring all optimized motion tracks corresponding to the target object;

and carrying out average calculation on all the optimized motion tracks to be used as the final motion track corresponding to the target object.

6. The multi-target tracking method based on millimeter wave equipment according to any one of claims 1 to 4, wherein the obtaining of the normalized distance velocity spectrum from the chirp signal corresponding to the antenna based on the millimeter wave radar specifically comprises:

for the antenna of the millimeter wave radar, acquiring a linear frequency modulation signal transmitted to the monitoring area by the antenna according to a preset time interval;

performing Fourier transform twice on the linear frequency modulation signal to obtain a distance and velocity spectrum, wherein the distance and velocity spectrum represents the relationship between distance and velocity;

and carrying out normalization processing on the distance velocity spectrum to obtain a normalized distance velocity spectrum.

7. The millimeter wave device-based multi-target tracking method according to any one of claims 1 to 4, wherein the obtaining of the angle of arrival corresponding to the target object according to the initial phase corresponding to the antenna specifically includes:

and after performing FFT (fast Fourier transform) on the original signal received by the antenna for two times, acquiring an initial phase corresponding to the antenna based on the frequency spectrum component corresponding to the distance of the target object.

8. A multi-target tracking system based on millimeter wave equipment is characterized by comprising:

the distance and velocity spectrum module is used for acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, and the distance and velocity spectrum represents the relation between the distance and the velocity in the monitoring area;

the motion track calculation module is used for acquiring a final motion track of the target object if the target object is judged to exist in the monitoring area based on the normalized distance velocity spectrum;

the wave arrival angle calculation module is used for acquiring a wave arrival angle corresponding to the target object according to the initial phase corresponding to the antenna;

and the tracking module is used for acquiring the arrival angle corresponding to the target object according to the initial phase corresponding to the antenna and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the millimeter wave device-based multi-target tracking method according to any one of claims 1 to 7 when executing the program.

10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the steps of the millimeter wave device based multi-target tracking method according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of target tracking, in particular to a multi-target tracking method and system based on millimeter wave equipment.

Background

In recent years, wireless positioning and tracking technology has become more and more widely applied in the fields of smart home, virtual reality, security monitoring and the like. Over the past decade, numerous wireless tracking technologies based on RFID, acoustic, Wi-Fi, and millimeter wave signals have evolved. Among them, active tracking technologies based on RFID and sound signals mostly require the target to carry specific devices, such as RFID tags, speakers, which limits their wide application in industry. Recently, passive tracking techniques, i.e., tracking techniques that do not require tracking of a target with a specific hardware device, are becoming more and more popular.

With the large-scale deployment and application of wireless Wi-Fi devices, Wi-Fi based tracking technology has received much attention. In recent work, commercial Wi-Fi devices are mainly used to calculate the position of a target by extracting characteristics such as signal angle of arrival (AoA), time of flight (ToF), doppler shift (DFS), and the like from Channel State Information (CSI) of wireless signals. The technology can be realized only by using commercial equipment, and a target to be detected does not need to carry specific equipment, so that the technology is widely applied to daily life. However, due to the limited bandwidth provided by commercial Wi-Fi devices and the limited number of antennas, the tracking task described above is typically only possible to a decimeter level of accuracy, and the number of targets tracked is limited, in most cases only a single object can be tracked.

In recent times, millimeter wave technology has been gaining increasing attention. Due to the high bandwidth provided by the millimeter wave device and the wireless signals with the wavelength of millimeter granularity, the millimeter wave device can realize positioning tracking with centimeter or even millimeter precision. However, the working range of the existing passive positioning technology based on millimeter wave devices is usually only a few meters away, and longer-distance target tracking cannot be realized.

At present, some industrial applications, such as a traveling control system, a mechanical arm system and a conveyor belt device, need to achieve tracking accuracy of a centimeter level in a longer range of tens of meters, and the existing work is difficult to achieve the requirement. Tracking over long distances presents the following challenges compared to short distances: (1) at long distances, the complexity of the surrounding environment increases considerably. When the distance is short, the reflection of the target to be detected occupies a main position, and the interference of the surrounding environment is small; when the distance increases, the reflection of the target to be detected is weakened, and the interference of the surrounding environment is increased, such as the reflection of a static object in the environment and the secondary reflection of the target, which all reduce the tracking precision; (2) when the working range is enlarged, a plurality of targets to be detected may appear in the monitoring area at the same time, and the reflections of the targets to be detected to the signals are mutually superposed, so that the positioning and tracking of the multiple targets are more difficult.

Therefore, there is a need for a multi-target tracking method that can overcome the above difficulties and achieve centimeter accuracy over a long distance.

Disclosure of Invention

The embodiment of the invention provides a multi-target tracking method and system based on millimeter wave equipment, which are used for solving the defect that multi-target tracking cannot be realized under a long distance condition in the prior art and realizing a multi-target high-precision tracking system under a long distance condition.

The embodiment of the invention provides a multi-target tracking method based on millimeter wave equipment, which comprises the following steps:

acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, wherein the distance and velocity spectrum represents the relation between the distance and the velocity in a monitoring area;

based on the normalized distance velocity spectrum, if the target object in the monitoring area is judged and known to exist, the final motion track of the target object is obtained;

acquiring a corresponding angle of arrival of the target object according to the initial phase corresponding to the antenna;

and acquiring a corresponding arrival angle of the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

According to the multi-target tracking method based on the millimeter wave device, the step of obtaining the final motion track of the target object based on the normalized distance velocity spectrum if the target object in the monitored area is judged and known to exist includes:

judging whether a target object exists in the monitoring area or not according to the normalized distance velocity spectrum;

if the target object in the monitoring area is judged and known to exist, all the target objects in the monitoring area are detected;

for a current target object, tracking the current target object through a preset particle filter algorithm based on the distance velocity spectrum, acquiring a motion track of the current target object, taking a next target object as the current target object again, eliminating the influence of the current target object in the distance velocity spectrum, taking the distance velocity spectrum without the influence as the distance velocity spectrum again, and repeatedly executing the step until the current target object is the last target object;

and taking the motion trail of the target object as the final motion trail.

According to the multi-target tracking method based on the millimeter wave device, the preset particle filtering algorithm is as follows:

particle initialization is performed after the target object has performed a start motion.

According to the multi-target tracking method based on the millimeter wave device in one embodiment of the present invention, the taking the motion trajectory of the target object as the final motion trajectory previously further includes:

for any two motion tracks, if the ending time of one motion track and the starting time of the other motion track are within a preset time error, and the ending position of one motion track and the starting position of the other motion track are within a preset distance error, combining the any two motion tracks into one motion track, and obtaining an optimized motion track corresponding to the target object;

and taking the optimized motion trail of the target object as the final motion trail again.

According to the multi-target tracking method based on the millimeter wave device in an embodiment of the present invention, the re-using the optimized motion trajectory of the target object as the final motion trajectory further includes:

acquiring all optimized motion tracks corresponding to the target object;

and carrying out average calculation on all the optimized motion tracks to be used as the final motion track corresponding to the target object.

According to the multi-target tracking method based on the millimeter wave equipment, the distance and velocity spectrum after normalization is obtained by the linear frequency modulation signal corresponding to the antenna based on the millimeter wave radar, and the method specifically comprises the following steps:

for the antenna of the millimeter wave radar, acquiring a linear frequency modulation signal transmitted to the monitoring area by the antenna according to a preset time interval;

performing Fourier transform twice on the linear frequency modulation signal to obtain a distance and velocity spectrum, wherein the distance and velocity spectrum represents the relationship between distance and velocity;

and carrying out normalization processing on the distance velocity spectrum to obtain a normalized distance velocity spectrum.

According to the millimeter wave device-based multi-target tracking method of one embodiment of the present invention, the obtaining of the angle of arrival corresponding to the target object according to the initial phase corresponding to the antenna specifically includes:

and after performing FFT (fast Fourier transform) on the original signal received by the antenna for two times, acquiring an initial phase corresponding to the antenna based on the frequency spectrum component corresponding to the distance of the target object.

The embodiment of the invention also provides a multi-target tracking system based on millimeter wave equipment, which comprises:

the distance and velocity spectrum module is used for acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, and the distance and velocity spectrum represents the relation between the distance and the velocity in the monitoring area;

the motion track calculation module is used for acquiring a final motion track of the target object if the target object is judged to exist in the monitoring area based on the normalized distance velocity spectrum;

the wave arrival angle calculation module is used for acquiring a wave arrival angle corresponding to the target object according to the initial phase corresponding to the antenna;

and the tracking module is used for acquiring the arrival angle corresponding to the target object according to the initial phase corresponding to the antenna and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

The embodiment of the invention also provides electronic equipment, which comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein when the processor executes the program, the steps of any one of the millimeter wave device-based multi-target tracking methods are realized.

Embodiments of the present invention further provide a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the millimeter wave device-based multi-target tracking method as described in any one of the above.

According to the multi-target tracking method and system based on the millimeter wave equipment, the multiple target objects are tracked with high precision based on the data acquired by the millimeter wave radar, the millimeter wave equipment which is created in the near period of time is taken as a basis, the advantages of short millimeter wave wavelength and high resolution are utilized, the observation value of the millimeter wave equipment and the continuity of distance and speed of the target objects during moving are combined, the data are fused through the particle filter, and the multiple targets are tracked one by one, so that the multi-target high-precision tracking system under the long-distance condition is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

Fig. 1 is a flowchart of a multi-target tracking method based on millimeter wave devices according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a multi-target tracking system based on millimeter wave devices according to an embodiment of the present invention;

fig. 3 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a flowchart of a multi-target tracking method based on millimeter wave devices according to an embodiment of the present invention, where the method includes:

the application scenario of the embodiment of the invention is that each antenna on the millimeter wave radar transmits a linear frequency modulation signal to a monitoring area, a target object in the monitored area of the linear frequency modulation signal is reflected back, and the antenna receives the reflected original signal.

S1, acquiring a normalized distance and velocity spectrum based on the linear frequency modulation signal corresponding to the antenna of the millimeter wave radar, wherein the distance and velocity spectrum represents the relation between the distance and the velocity in the monitoring area;

firstly, a millimeter wave radar generally has a plurality of antennas, each antenna transmits a chirp signal according to a predetermined time interval, and according to the chirp signal of each time interval, a distance and velocity spectrum of a monitored area in the time interval can be calculated, wherein the distance and velocity spectrum represents a corresponding relationship between a distance and a velocity in the monitored area, and represents a corresponding relationship between the distance and the velocity of the monitored area and the millimeter wave radar.

Specifically, a distance velocity spectrum can be obtained by performing two fast fourier transforms on the linear frequency modulated signal.

The horizontal and vertical axes in the distance velocity spectrum (RVS) represent distance and radial velocity, respectively. The higher the amplitude of a location in the RVS, the higher the probability that an object is present at the corresponding distance and speed. However, the higher amplitude places in the RVS do not necessarily correspond to the object to be measured, but may also be other disturbances in the environment.

Considering that there is a certain fluctuation in the amplitude of the RVS at different times, the RVS is normalized in the embodiment of the present invention, that is, a normalized distance velocity spectrum (NRVS for short) is obtained, and the amplitude in the NRVS ranges from 0 to 1.

S2, based on the normalized distance velocity spectrum, if the target object in the monitored area is judged and known to exist, obtaining the final motion track of the target object;

and extracting a part with the speed not being 0 in NRVS based on the normalized distance and speed spectrum, calculating the maximum amplitude value of the part, and considering that a moving target object exists in the monitoring area when the maximum amplitude values of a plurality of continuous frames exceed the preset amplitude value.

And if a plurality of moving target objects exist in the monitoring area, acquiring a final motion track corresponding to each moving target object.

S3, acquiring the angle of arrival corresponding to the target object according to the initial phase corresponding to the antenna;

in order to obtain the position of the target object in the two-dimensional plane, the embodiment of the invention utilizes a linear receiving antenna array in the millimeter wave device to measure the signal angle of arrival (AoA) of the target.

If the distance between the antennas in the receiving antenna array is d, the relationship between the phase difference Φ of the signals received by different antennas and the arrival angle θ of the signals can be expressed as:

where λ represents the wavelength of the signal. Theoretically, AoA can be calculated by measuring the signal phase difference of different antennas.

It can be seen from the formula that the signal arrival angle can be obtained by only calculating the initial phase of the antenna.

And S4, acquiring the arrival angle corresponding to the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

The final motion track of the target object is a one-dimensional motion track of the target object, the arrival angle can represent the motion direction of the target object, and the target object can be tracked based on the parameters.

According to the multi-target tracking method based on the millimeter wave equipment, the multiple target objects are tracked with high precision based on the data acquired by the millimeter wave radar, based on the millimeter wave equipment which is raised in a short period of time, the advantages of short millimeter wave wavelength and high resolution are utilized, the observation value of the millimeter wave equipment and the continuity of distance and speed of the target objects during moving are combined, data fusion is carried out through the particle filter, and the multiple targets are tracked one by one, so that the multi-target high-precision tracking system under the long-distance condition is realized.

On the basis of the foregoing embodiment, preferably, the acquiring a final motion trajectory of the target object if it is determined that the target object exists in the monitored area based on the normalized distance velocity spectrum specifically includes:

judging whether a target object exists in the monitoring area or not according to the normalized distance velocity spectrum;

specifically, a portion of NRVS where the velocity is not 0 is extracted, and the maximum amplitude therein is calculated. And when the maximum amplitude values of a plurality of continuous frames exceed the preset amplitude value, the moving target to be detected exists in the monitoring area.

If the target object in the monitoring area is judged and known to exist, all the target objects in the monitoring area are detected;

according to the method, if the target object exists in the monitored area, all the target objects in the monitored area are detected.

For a current target object, tracking the current target object through a preset particle filter algorithm based on the distance velocity spectrum, acquiring a motion track of the current target object, taking a next target object as the current target object again, eliminating the influence of the current target object in the distance velocity spectrum, taking the distance velocity spectrum without the influence as the distance velocity spectrum again, and repeatedly executing the step until the current target object is the last target object;

for the situation that a plurality of target objects exist, a mode of detecting and tracking one by one is adopted, firstly, if one current target object is detected, the current target object is tracked through a preset particle filter algorithm to obtain a motion track of the current target object, then, the next target object is used as the current target object again, the influence of the current target object in a distance velocity spectrum is eliminated, namely, the distance velocity spectrum is updated again, the distance velocity spectrum without the influence is used as the distance velocity spectrum again, and the process is repeated until the current target object is the last target object.

And taking the motion trail of the target object as the final motion trail.

And taking the finally obtained motion trail of the target object as a final motion trail.

On the basis of the foregoing embodiment, preferably, the preset particle filtering algorithm is:

particle initialization is performed after the target object has performed a start motion.

Specifically, in the embodiment of the present invention, the preset particle filtering algorithm is as follows:

when the target object is detected to exist, the preset particle filter is used for tracking the target to be detected. Before tracking, the particles are initialized and the initial state of the particles is determined. The state of each particle contains both the position and the velocity of the particle. In the conventional particle filter operation, particle initialization is usually performed at the beginning of a monitoring period, but in the present invention, the object to be measured does not usually start moving yet at the beginning of monitoring, so if particle initialization is performed at the beginning of the monitoring period, the object to be measured and a static object cannot be effectively distinguished.

In order to better reduce the influence of static objects, the embodiment of the invention selects to perform particle initialization after the target object starts to move.

In particle initialization, a weight value of each position in the NRVS is calculated, and then the distribution of particles is initialized according to the weight value, where the higher the weight value is, the higher the possibility that the particles exist is.

When calculating the weight, the following two principles are followed: (1) the higher the amplitude value in NRVS, the larger the corresponding weight value; (2) the closer the position in NRVS to the highest point of amplitude value, the larger the corresponding weight value. In addition, in order to reduce the disturbance of the stationary object, the particles are not provided at the position where the velocity is 0 in NRVS at the time of initialization.

After initializing the particles, updating, weight calculation and resampling of the particles are performed in sequence, and the state of the particles at each frame time is obtained. In the particle update state, the state of the particles in the next frame is predicted by using the distance and the speed of each particle in the previous frame, and the specific calculation method is as follows:

wherein the content of the first and second substances,representing the distance and velocity of a frame on the ith particle,represents the distance and velocity, t, of the next frame of the ith particle_fpRepresenting the duration of each frame. Embodiments of the present invention add delta to account for possible fluctuations and random noise in the measurements_dAnd delta_vTwo gaussian random variables.

After the particle update, the weight of each particle is calculated. The weight of the particle is mainly calculated by the amplitude of NRVS, and the higher the amplitude is, the higher the weight of the particle is. The specific calculation formula is as follows:

wherein d is_iRepresents the logarithmic value of the amplitude of the ith particle in NRVS, and sigma is the preset standard deviation.

After the weight of each particle is calculated, resampling of the particles is performed, the particles with higher weight are retained, and the particles with lower weight are discarded.

After the state of the particles in the whole monitoring period is obtained, the product of the weights of each particle in all frames is calculated, then the part of the particles with higher weights are selected, and the distances and the speeds of the part of the particles are averaged to obtain the track of the target to be measured.

On the basis of the foregoing embodiment, preferably, the taking the motion trajectory of the target object as the final motion trajectory further includes:

for any two motion tracks, if the ending time of one motion track and the starting time of the other motion track are within a preset time error, and the ending position of one motion track and the starting position of the other motion track are within a preset distance error, combining the any two motion tracks into one motion track, and obtaining an optimized motion track corresponding to the target object;

and taking the optimized motion trail of the target object as the final motion trail again.

In some cases, the secondary reflections from the target object are also relatively strong, producing a higher amplitude at the corresponding location of NRVS, but the duration of the secondary reflections is typically relatively short compared to the direct reflections from the target object. Therefore, the track with too short motion time is discarded, and the influence of secondary reflection is reduced.

In tracking, a moving target object may pass by a stationary object and gradually move away from the millimeter wave device. After the target object passes by the static object, the target object may be farther away than the static object, and thus the reflection of the static object may be stronger than the reflection of the target object, so the system may assume that the target object is stationary at this time. After the target object is tracked, the system monitors the movement of the target object after the target object passes through the static object, and considers the original target object as a new target object and then monitors the new target object.

Thus, a single moving target object is regarded as two target objects, and the number of moving target objects is erroneous.

To solve this problem, a fusion of the trajectories is required. If the end time and the end position of one track are close to the start time and the start position of the other track, the tracks are considered as the tracks of the same target object, and the fusion operation is carried out on the tracks. Therefore, the accuracy of detecting the number of the target objects is improved.

On the basis of the foregoing embodiment, preferably, the re-using the optimized motion trajectory of the target object as the final motion trajectory further includes:

acquiring all optimized motion tracks corresponding to the target object;

and carrying out average calculation on all the optimized motion tracks to be used as the final motion track corresponding to the target object.

Specifically, each antenna of the millimeter wave radar transmits a chirp signal, and therefore, the same target object may reflect chirp signals transmitted from a plurality of antennas, so that the same target object may be detected by the plurality of antennas, and each antenna may calculate a motion trajectory of the target object.

And carrying out average calculation on all the motion tracks of the target object to obtain the final motion track of the target object.

On the basis of the foregoing embodiment, preferably, the obtaining a normalized distance and velocity spectrum based on a chirp signal corresponding to an antenna of a millimeter wave radar specifically includes:

for the antenna of the millimeter wave radar, acquiring a linear frequency modulation signal transmitted to the monitoring area by the antenna according to a preset time interval;

specifically, each antenna of the millimeter wave radar transmits a chirp signal to a monitoring area at a certain preset time interval.

Performing Fourier transform twice on the linear frequency modulation signal to obtain a distance and velocity spectrum, wherein the distance and velocity spectrum represents the relationship between distance and velocity;

and carrying out Fourier transform twice on each linear frequency modulation signal to obtain a distance velocity spectrum.

And carrying out normalization processing on the distance velocity spectrum to obtain a normalized distance velocity spectrum.

And then, carrying out normalization processing on the obtained distance speed to obtain a normalized distance speed spectrum.

On the basis of the foregoing embodiment, the obtaining, according to the initial phase corresponding to the antenna, the angle of arrival corresponding to the target object specifically includes:

and after performing FFT (fast Fourier transform) on the original signal received by the antenna for two times, acquiring an initial phase corresponding to the antenna based on the frequency spectrum component corresponding to the distance of the target object.

Theoretically, the arrival angle AoA can be calculated by measuring the phase difference of signals of different antennas, however, the calculation of the arrival angle AoA by directly using the phase of the original signal may generate a large error due to the existence of environmental noise and the mutual superposition of multiple target reflections. Fortunately, the initial phase of each frequency component can be extracted by FFT. After FFT of the signal, a spectrogram taking the value of a complex number is obtained, where the phase of each point corresponds to the initial phase of each spectral component in the time domain.

The two-dimensional tracking algorithm of the embodiment of the invention is as follows. For each receiving antenna, the number of detected target objects and their trajectories can be obtained. And matching and corresponding the tracks obtained by each antenna to obtain the overall track and speed information of each target object. And performing FFT (fast Fourier transform) on the original signal of each antenna, determining the corresponding frequency spectrum component according to the distance of each target, searching to obtain the initial phase corresponding to each antenna, and calculating to obtain the AoA.

However, if a plurality of target objects are simultaneously located on a circle centered on the millimeter wave device, their distances from the millimeter wave device will be the same, and the initial phases of the corresponding spectral components of the respective target objects will be mixed together and cannot be distinguished. Considering that the radial velocities of the target objects are usually different, FFT can be performed again to obtain the RVS of each receiving antenna, and then the initial phase of each receiving antenna is determined by the distance and velocity of each target object, and AoA is calculated.

Fig. 2 is a schematic structural diagram of a multi-target tracking system based on millimeter wave devices according to an embodiment of the present invention, and as shown in fig. 2, the system includes: a distance velocity spectrum module 201, a motion trajectory calculation module 202, an angle of arrival calculation module 203, and a tracking module 204, wherein:

the distance and velocity spectrum module 201 is configured to obtain a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, where the distance and velocity spectrum represents a relationship between a distance and a velocity in a monitored area;

the motion trajectory calculation module 202 is configured to, based on the normalized distance velocity spectrum, obtain a final motion trajectory of the target object if it is determined that the target object exists in the monitored area;

the angle of arrival calculation module 203 is configured to obtain an angle of arrival corresponding to the target object according to the initial phase corresponding to the antenna;

the tracking module 204 is configured to obtain a corresponding angle of arrival of the target object according to the initial phase corresponding to the antenna, and track the target object based on the final motion trajectory, the speed of the target object, and the angle of arrival.

The present embodiment is a system embodiment corresponding to the above method, and please refer to the above method embodiment for details, which is not described herein again.

Fig. 3 is a schematic entity structure diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 3, the electronic device may include: a processor (processor)310, a communication Interface (communication Interface)320, a memory (memory)330 and a communication bus 340, wherein the processor 310, the communication Interface 320 and the memory 330 communicate with each other via the communication bus 340. Processor 310 may invoke logic instructions in memory 330 to perform a millimeter wave device based multi-target tracking method comprising:

acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, wherein the distance and velocity spectrum represents the relation between the distance and the velocity in a monitoring area;

based on the normalized distance velocity spectrum, if the target object in the monitoring area is judged and known to exist, the final motion track of the target object is obtained;

acquiring a corresponding angle of arrival of the target object according to the initial phase corresponding to the antenna;

and acquiring a corresponding arrival angle of the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

In addition, the logic instructions in the memory 330 may be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

In another aspect, an embodiment of the present invention further provides a computer program product, where the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, where the computer program includes program instructions, and when the program instructions are executed by a computer, the computer is capable of executing a millimeter wave device-based multi-target tracking method provided by the foregoing method embodiments, where the method includes:

acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, wherein the distance and velocity spectrum represents the relation between the distance and the velocity in a monitoring area;

based on the normalized distance velocity spectrum, if the target object in the monitoring area is judged and known to exist, the final motion track of the target object is obtained;

acquiring a corresponding angle of arrival of the target object according to the initial phase corresponding to the antenna;

and acquiring a corresponding arrival angle of the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

In still another aspect, an embodiment of the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program is implemented by a processor to execute the method for multiple target tracking based on millimeter wave devices provided in the foregoing embodiments, where the method includes:

acquiring a normalized distance and velocity spectrum based on a linear frequency modulation signal corresponding to an antenna of the millimeter wave radar, wherein the distance and velocity spectrum represents the relation between the distance and the velocity in a monitoring area;

based on the normalized distance velocity spectrum, if the target object in the monitoring area is judged and known to exist, the final motion track of the target object is obtained;

acquiring a corresponding angle of arrival of the target object according to the initial phase corresponding to the antenna;

and acquiring a corresponding arrival angle of the target object according to the initial phase corresponding to the antenna, and tracking the target object based on the final motion track, the speed of the target object and the arrival angle.

The above-described embodiments of the apparatus are merely illustrative, and 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 place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.