Adaptive radar frame filtering system and method

Abstract

A system and method for adaptive radar frame filtering are disclosed. The maximum signal strength at zero velocity is obtained from a range bin containing detections corresponding to an object within a range Doppler representation of a set of radar frames acquired during a time period preceding the radar frame. A motion vector representing the magnitude and direction of a determined motion of the radar device at the time the radar frame is acquired is obtained. A range Doppler representation of the radar frame is generated, and a direction vector representing the direction from the radar device to the object is determined. The radial relative velocity between the object and the radar device is determined based on the motion vector and the direction vector. For a range bin containing detections corresponding to the object in the range Doppler representation, an interval is set around the determined radial relative velocity based on the radial relative velocity and the maximum signal strength. If the detection is within the interval, the representation of the object is filtered out from the radar frame; if the detection is outside the interval, the detection corresponding to the object is not filtered out from the radar frame.

Description

Technical Field

[0001] The present invention relates to the processing of radar frames, and more particularly, to the filtering out of representations of objects from radar frames captured by a radar device. Background Technology

[0002] When a radar device is mounted on a fixed bracket and used to monitor a scene, each radar frame can be processed, thereby removing radar data related to static objects such as the ground, buildings, and parked cars from each frame. This processing can be performed in the application when moving objects in the scene are more interesting than static objects. Processing is fairly straightforward when the radar device is firmly mounted on a fixed, rigid support such as a wall. However, if the radar device is mounted on a stationary, non-rigid support, such as a non-rigid rod that can vibrate or sway back and forth, the radar device may move, resulting in relative movement between the static object and the moving radar device. Therefore, in this case, since the static object no longer appears static due to the movement of the radar device, radar data related to the static object may not be removed from the radar frame.

[0003] Therefore, improvements in this regard are desirable. Summary of the Invention

[0004] In view of the above, the object of the present invention is to mitigate, alleviate or eliminate one or more of the above-mentioned defects and disadvantages in the art, either alone or in combination.

[0005] According to a first aspect, a method is provided for adaptively filtering out representations of objects from radar frames captured by a radar device. The method involves acquiring the maximum signal strength at zero velocity in a range bin containing a detection corresponding to an object within a range Doppler representation of a set of radar frames captured by the radar device during a time period preceding the radar frame, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in a scene monitored by the radar device. A motion vector representing the amplitude and direction of a determined motion of the radar device due to the oscillating motion of the radar device is acquired. A radar frame captured by the radar device having the determined amplitude and direction of motion is received, and a range Doppler representation of the radar frame is generated. A direction vector representing the direction from the radar device to the object is determined, and a radial relative velocity between the object and the radar device is determined based on the acquired motion vector and the determined direction vector. For a range bin in the range Doppler representation containing a detection corresponding to the object, an interval is set around the determined radial relative velocity based on the determined radial relative velocity and the determined maximum signal strength. If the detection is within the set interval, the representation of the object is filtered out from the radar frame; if the detection is outside the set interval, the detection corresponding to the object is not filtered out from the radar frame.

[0006] By determining the motion vector of the radar device when it acquires a radar frame, and by determining the direction vector from the radar to the object, the radial relative velocity between the object and the radar device at the time the radar frame is acquired can be determined. This radial relative velocity, along with the maximum signal strength, is then used to determine the interval around the radial relative velocity in the range bin of the range Doppler representation of the radar frame, where the range bin includes the detection corresponding to the object. The interval is then used to determine whether to filter out the representation of the object from the radar frame. By basing the interval on the determined radial relative velocity, static objects that appear to have a velocity other than zero in the range Doppler representation of the radar frame due to the oscillating motion of the radar device can be identified as static objects, and / or their representations can be filtered out from the radar frame.

[0007] Because the spacing is partly based on the radial relative velocity determined when the radar frame is acquired, the filtering is more adapted to the current radial relative velocity. If a method of generally increasing the spacing is used, the risk of slowly moving objects being filtered out from the radar frame is higher.

[0008] In one embodiment, the action of obtaining the maximum signal strength at zero velocity includes: receiving a set of radar frames captured by a radar device during a time period preceding the radar frames, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device; generating range Doppler representations of the set of radar frames, and identifying a detection corresponding to the object in each of the range Doppler representations of the set of radar frames; determining the signal strength at zero velocity of the detection corresponding to the object in each range Doppler representation, and the maximum signal strength is determined as the maximum value of the determined signal strength.

[0009] According to a second aspect, a method is provided for adaptively filtering object representations from a first radar frame among a plurality of radar frames captured by a radar device. For each of the plurality of radar frames, the maximum signal strength at zero velocity is obtained in a range bin containing the detection corresponding to the object in a set of radar frames captured by the radar device during a time period preceding the first radar frame, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in a scene monitored by the radar device. Furthermore, a motion vector representing the amplitude and direction of a determined motion of the radar device due to the oscillating motion of the radar device is obtained. Additionally, radar frames captured by the radar device having the determined amplitude and direction of motion are received, and a range Doppler representation of the radar frames is generated. A direction vector representing the direction from the radar device to the detected object is determined, and a radial relative velocity between the object and the radar device is determined based on the determined motion vector and the determined direction vector. For a range bin containing the detection corresponding to the object in the range Doppler representation, an interval is set around the determined radial relative velocity based on the determined radial relative velocity and the determined maximum signal strength. Then, a common interval is calculated as the average of the intervals set for the plurality of radar frames. If the detection corresponding to the object is located within the calculated common interval of the range bin in the range Doppler representation of the first radar frame, the detection corresponding to the object is filtered out from the first radar frame. If the detection corresponding to the object is located outside the calculated common interval of the range bin in the range Doppler representation of the first radar frame, the detection corresponding to the object is not filtered out from the first radar frame.

[0010] As described in relation to the method according to the first aspect, by means of the method according to the second aspect, a static object that appears to have a velocity different from zero velocity in the range Doppler representation of a radar frame due to the oscillating motion of the radar device can be identified as a static object, and / or the representation of such an object can be filtered out from the radar frame.

[0011] Furthermore, by calculating the common interval as the average of the intervals set across multiple radar frames, robustness against noise and error can be improved.

[0012] In this embodiment, the oscillating motion of the radar device is due to the oscillating motion of the support structure on which the radar device is mounted.

[0013] According to a third aspect, a non-transitory computer-readable storage medium is provided, having instructions stored thereon, which, when executed by a processing device, are used to implement the method according to the first aspect or the method according to the second aspect.

[0014] According to a fourth aspect, an apparatus is provided for adaptively filtering out representations of objects from radar frames captured by a radar device. The apparatus includes circuitry configured to perform a first acquisition function, a second acquisition function, a receiving function, a generating function, a first determination function, a second determination function, a setting function, and a filtering function. The first acquisition function is configured to acquire the maximum signal strength at zero velocity in a range bin, including a detection corresponding to an object, of a set of radar frames captured by the radar device during a time period preceding the radar frame, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in a scene monitored by the radar device. The second acquisition function is configured to acquire a motion vector representing the amplitude and direction of a determined motion of the radar device due to the oscillating motion of the radar device. The receiving function is configured to receive radar frames captured by the radar device having the determined amplitude and direction of motion. The generating function is configured to generate a range Doppler representation of the radar frames. The first determination function is configured to determine a direction vector representing the direction from the radar device to the object. The second determination function is configured to determine the radial relative velocity between the object and the radar device based on the determined motion vector and the determined direction vector. The setting function is configured to, for a range bin in the range Doppler representation that includes a detection corresponding to an object, set an interval around a determined radial relative velocity based on a determined radial relative velocity and a determined maximum signal strength. The filtering function is configured to filter out the representation of the object from the first radar frame if the detection corresponding to the object is within the set interval, and to prevent the filtering out of the representation of the object from the first radar frame if the detection corresponding to the object is outside the set interval.

[0015] Where applicable, the aforementioned optional additional features of the method according to the first aspect also apply to the apparatus according to the fourth aspect. To avoid repetition, refer to the foregoing.

[0016] According to a fifth aspect, an apparatus is provided for adaptively filtering an object representation from a first radar frame of a plurality of radar frames captured by a radar device. The apparatus includes circuitry configured to perform a first acquisition function, a second acquisition function, a receiving function, a generating function, a first determination function, a second determination function, and a setting function for each of the plurality of radar frames. The first acquisition function is configured to acquire the maximum signal strength at zero velocity in a range bin, including a detection corresponding to an object, of a set of radar frames captured by the radar device during a time period preceding the radar frame, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in a scene monitored by the radar device. The second acquisition function is configured to acquire a motion vector representing the amplitude and direction of a determined motion of the radar device due to the oscillating motion of the radar device. The receiving function is configured to receive a radar frame captured by the radar device having the determined amplitude and direction of motion. The generating function is configured to generate a range Doppler representation of the radar frame. The first determination function is configured to determine a direction vector representing the direction from the radar device to the object. The second determination function is configured to determine the radial relative velocity between the object and the radar device based on the determined motion vector and the determined direction vector. The setting function is configured to, for a range bin in the range Doppler representation including a detection corresponding to an object, set an interval around a determined radial relative velocity based on a determined radial relative velocity and a determined maximum signal strength. The circuit is further configured to perform a calculation function and a filtering function. The calculation function is configured to calculate a common interval as the average of the setting intervals for multiple radar frames. The filtering function is configured to filter out the representation of the object from the first radar frame if the detection corresponding to the object is within the common interval in the range bin of the range Doppler representation of the first radar frame, and to prevent the filtering out of the representation of the object from the first radar frame if the detection corresponding to the object is outside the common interval in the range bin of the range Doppler representation of the first radar frame.

[0017] In this embodiment, the oscillating motion of the radar device is due to the oscillating motion of the support structure on which the radar device is mounted.

[0018] The further scope of the invention will become apparent from the detailed description given below. However, it should be understood that although preferred embodiments of the invention are shown, various variations and modifications within the scope of the invention will become apparent to those skilled in the art from the detailed description; therefore, the detailed description and specific examples are given by way of illustration only.

[0019] Therefore, it will be understood that the present invention is not limited to such devices and methods because certain components of the described apparatus or the operation of the described method can be modified. It will also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It should be noted that, as used in the specification and appended claims, the articles “a,” “the,” and “the” are intended to indicate the presence of one or more elements unless the context clearly specifies otherwise. Thus, for example, a reference to “a unit” or “the unit” can include several devices, etc. Furthermore, the words “comprising,” “including,” “containing,” and similar wording do not exclude other elements or steps. Attached Figure Description

[0020] The above and other aspects of the invention will now be described in more detail with reference to the accompanying drawings. The drawings should not be considered limiting, but rather for illustration and understanding.

[0021] Figure 1a and Figure 1b A flowchart is shown relating to an embodiment of a method for adaptively filtering representations of objects from radar frames captured by a radar device.

[0022] Figure 2a and Figure 2b A flowchart is shown relating to an embodiment of a method for adaptively filtering representations of objects from a first radar frame of a plurality of radar frames captured by a radar device.

[0023] Figure 3 A block diagram is shown relating to an embodiment of a device for adaptively filtering out representations of objects from radar frames captured by a radar device.

[0024] Figure 4 A block diagram is shown relating to an embodiment of an apparatus for adaptively filtering out representations of objects from a first radar frame of a plurality of radar frames captured by a radar device. Detailed Implementation

[0025] In the following description, the invention will be illustrated with reference to the accompanying drawings, in which presently preferred embodiments of the invention are shown. However, the invention may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein.

[0026] This invention applies to situations where a radar device is stationary but not rigidly mounted, such that relative oscillating motion may exist between the static object in the scene being monitored by the radar device and the radar device itself due to the oscillating motion of the radar device relative to a stationary object in the scene being monitored by the radar device. For example, this may occur when the radar device is mounted on a stationary, non-rigid support (e.g., a non-rigid rod that can oscillate back and forth). Such oscillation may occur, for example, due to wind or other physical impacts on the non-rigid support.

[0027] A radar device is a type of device capable of determining the velocity of an object detected by the radar device. For example, a radar device could be a frequency-modulated continuous wave (FMCW) radar device that uses a beat signal (linear frequency modulation), the frequency of which varies over time, typically rising or falling. As another example, a radar device could be a phase-modulated continuous wave (PMCW) radar device.

[0028] A radar device is further characterized by its ability to determine the type of direction vector from the radar device to the object detected by the radar device. For example, the radar device could be a multiple-input multiple-output (MIMO) radar device.

[0029] Now regarding Figure 1a and Figure 1b The flowchart in the diagram describes an embodiment of a method 100 for adaptively filtering representations of objects from radar frames captured by a radar device. Method 100 relates to adaptive filtering with respect to a single object. However, the principles of the method can be applied sequentially or in parallel to adaptive filtering relating to all objects in a radar frame.

[0030] Method 100 includes acquiring the maximum signal strength at zero velocity in a range chamber, including the detection corresponding to the object, within the range Doppler representation of a set of radar frames captured by a radar device, at step S110. Here, signal strength refers to the signal strength of the reflected signal received at the radar device. The set of radar frames is acquired during a time period preceding the radar frames (i.e., prior to the time of radar frame acquisition). Furthermore, this time period is made long enough to include at least one cycle of the oscillating motion of the radar device. This is to ensure that the maximum signal strength of the detection corresponding to the object will be at or at least close to zero velocity in the range Doppler representation of at least one radar frame in the set of radar frames. For example, if the period of the oscillating motion is 2 seconds and there are 10 radar frames per second, then the set of radar frames should include at least 20 radar frames.

[0031] For an FMCW radar device, a range-Doppler representation can be generated by arranging the data logic of the analog-to-digital conversion corresponding to down-conversion linear frequency modulation into columns of a matrix. Each column is analyzed using an FFT to determine objects within the radar device's range, such that each row is a range bin containing the detection of objects within a distance interval relative to the radar device. Conversely, the velocity of each row (range bin) relative to the radar device is analyzed along the rows using an FFT, such that each column contains the detection of objects within a velocity interval associated with the radar device. The range-Doppler representation includes detections of objects whose positions relative to the vertical y-axis correspond to different distances from the radar device in the scene. It also includes detections of objects whose positions relative to the horizontal x-axis correspond to the radial velocities between the radar device and the objects.

[0032] As described above, regarding an object description method 100, it is generally possible to filter all objects in a radar frame. Then, the maximum signal strength at zero velocity in each range cell across the set of radar frames can be obtained. Then, based on the corresponding maximum signal strength, the remaining steps S120-S194 of method 100 are performed for each range cell in the radar frame. To reduce the number of range cells for which method 100 is performed, it can be limited to include range cells that may contain static objects. This can be achieved by identifying all range cells that have a maximum signal strength at zero velocity exceeding a threshold indicating detection corresponding to the object. Then, the remaining steps of method 100 are performed only on the identified range cells in the radar frame.

[0033] The action of obtaining the maximum signal strength at zero velocity in S110 may include receiving a set of radar frames captured by the radar device during a time period preceding the radar frames. Then, a range Doppler representation of the set of radar frames is generated. The signal strength at zero velocity is then determined in a range bin that includes a detection corresponding to the object within each range Doppler representation, and the maximum signal strength is determined as the maximum value of the determined signal strength.

[0034] The method further includes obtaining, in step S120, a motion vector representing the amplitude and direction of a determined motion of the radar device relative to stationary objects in a scene monitored by the radar device. The relative motion between the radar device and the stationary objects in the scene is due to the oscillating motion of the radar device. Furthermore, since the motion of the radar device is oscillating, the amplitude and direction of the radar device's motion will change over time. Therefore, the amplitude and direction of the motion are determined when a radar frame is acquired by the radar device. The motion vector can be obtained by receiving measurements taken when the radar frame is acquired using accelerometers arranged in the radar device. Alternatively, the motion vector can be obtained by determining the relative velocities of a set of objects in the scene that have been identified as stationary in the scene and have known positions relative to the radar device.

[0035] Method 100 further includes: receiving a radar frame captured by the radar device in S130 and generating a range Doppler representation of the radar frame in S140. As described above, when the radar frame is captured, the radar device has a defined amplitude and direction of movement. As described above, the range Doppler representation includes detecting that the position relative to the vertical y-axis corresponds to an object in the scene at a different distance from the radar device. The position relative to the horizontal x-axis corresponds to the radial velocity between the radar device and the object. Due to oscillating motion, when the radar frame is captured, the radar device has a defined amplitude and direction of movement relative to a stationary object. Therefore, the detection corresponding to a static object in the scene will not be located at the position corresponding to zero velocity in the range Doppler representation.

[0036] Method 100 further includes: determining, in S150, a direction vector representing the direction from the radar device to the object, and determining, in S160, the radial relative velocity between the object and the radar device based on the acquired motion vector and the determined direction vector. The radar device may be a MIMO radar device. The radar device may also be an FMCW radar device or a PMCW radar device.

[0037] For the range bins in the range Doppler representation that include detections corresponding to the object, an S170 interval is set around a determined radial relative velocity. The interval is set relative to the radar frame and is based on a determined radar frame-specific radial relative velocity and a determined maximum signal strength. The interval is used to determine whether the representation of the object should be filtered out of the radar frame. Specifically, under condition C190 where the detection is within the set interval, the representation of the object S192 is filtered out of the radar frame, and under condition C190 where the detection is outside the set interval, the representation of the object S194 is not filtered out of the radar frame. Detection within the set interval means that any energy outside the interval will be below a threshold considered for detection. Detection outside the set interval means that energy outside the interval will be above a threshold considered for detection.

[0038] Setting intervals around a defined radial relative velocity means that the intervals begin below the defined radial relative velocity and end above it. For example, the intervals can be symmetrical about the defined radial relative velocity, i.e., such that the defined radial relative velocity is in the middle of the interval.

[0039] Instead of the fixed guard interval around zero velocity set for all radar frames in the prior art, an interval is set around a determined radial relative velocity. The interval is set in part based on the determined radial relative velocity, which is determined based on the amplitude and direction of the radar device's determined motion when the radar frame is acquired. Therefore, the interval set for the radar frames is adapted to the determined amplitude and direction of the radar device's determined motion when the radar frame is acquired. By adaptively setting the interval taking into account the determined maximum signal strength and the determined relative radial velocity, filtering is made suitable so that even if the prior art method using a fixed guard interval were used, the detection in the range chamber would not be considered to correspond to a static object, and the representation of the object would be filtered out from the radar frame. For example, the larger the radial relative velocity, the larger the interval can be set.

[0040] Figure 2a and Figure 2b A flowchart is shown relating to an embodiment of a method for adaptively filtering representations of objects from a first radar frame of a plurality of radar frames captured by a radar device.

[0041] In method 200, for each radar frame i in a plurality of radar frames consisting of n radar frames, the following actions are performed: acquiring the maximum signal strength (S210), acquiring the motion vector (S220), receiving the radar frame (S230), generating the range Doppler representation (S240), determining the direction vector (S250), determining the radial relative velocity (S260), and setting the interval (S270). For details and options of these actions S210-S270, refer to the section on... Figure 1a and Figure 1b Details and options of the corresponding actions S110-S170 for method 100 described.

[0042] Therefore, an interval is set for the range bins for each radar frame. Then, the common interval of the range bins S280 is calculated as the average of the intervals set for multiple radar frames. The common interval is then used to determine whether the representation of an object should be filtered out from the first radar frame. The common interval lies around the radial relative velocity determined when the first radar frame is acquired by the radar device. Specifically, under condition C290, if the object is detected within the common interval, the representation of object S292 is filtered out from the radar frame; and under condition C290, if the object is detected outside the common interval, the representation of object S194 is not filtered out from the radar frame.

[0043] For further details and options regarding the filtering actions S290-S294 of method 200, please refer to the relevant documentation. Figure 1a and Figure 1b The details and options of the actions S190-S194 corresponding to the described method 100.

[0044] Figure 3 A block diagram is shown relating to an embodiment of a device 300 for adaptively filtering out representations of objects from radar frames captured by a radar device.

[0045] Device 300 includes circuitry 310. Circuitry 310 is configured to perform the functions of device 300. Circuitry 310 may include processor 312, such as a central processing unit (CPU), graphics processing unit (GPU), tensor processing unit (TPU), microcontroller, or microprocessor. Processor 312 is configured to execute program code. The program code may, for example, be configured to perform the functions of device 300.

[0046] Device 300 may further include memory 320. Memory 320 may be one or more of a buffer, flash memory, hard disk drive, removable media, volatile memory, non-volatile memory, random access memory (RAM), or other suitable devices. In a typical arrangement, memory 320 may include non-volatile memory for long-term data storage and volatile memory that functions as device memory for circuit 310. Memory 320 may exchange data with circuit 310 via a data bus. Additional control lines and address buses may also exist between memory 320 and circuit 310.

[0047] The functionality of device 300 can be manifested in the form of executable logic routines (e.g., lines of code, software programs, etc.) stored on a non-transitory computer-readable medium (e.g., memory 320) of device 300 and executed by circuitry 310 (e.g., using processor 312). Furthermore, the functionality of device 300 can be a standalone software application or part of a software application that performs additional tasks related to device 300. The described functionality can be considered as a method configured to be executed, for example, by the processing unit of processor 312 of circuitry 310. Moreover, although the described functionality can be implemented in software, such functionality can also be implemented via dedicated hardware or firmware, or certain combinations of hardware, firmware, and / or software.

[0048] Circuit 310 is configured to perform a first acquisition function 331, a second acquisition function 332, a receiving function 333, a generating function 334, a first determining function 335, a second determining function 336, a setting function 337, and a filtering function 339.

[0049] The first acquisition function 331 is configured to acquire the maximum signal strength at zero velocity in the range Doppler representation of a set of radar frames captured by the radar device during a time period prior to the radar frame, including a range bin corresponding to the object. The time period includes at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device. The second acquisition function 332 is configured to acquire a motion vector representing the amplitude and direction of a determined motion of the radar device due to the oscillating motion of the radar device. The receiving function 333 is configured to receive radar frames captured by the radar device having a determined amplitude and direction of motion. The generating function 334 is configured to generate a range Doppler representation of the radar frames. The first determining function 335 is configured to determine a direction vector representing the direction from the radar device to the object. The second determining function 336 is configured to determine the radial relative velocity between the object and the radar device based on the determined motion vector and the determined direction vector. The setting function 337 is configured to set an interval around the determined radial relative velocity for the range bin corresponding to the object in the range Doppler representation, based on the determined radial relative velocity and the determined maximum signal strength. The filtering function 339 is configured to filter out the representation of an object from the first radar frame when the detection corresponding to the object is within a set interval, and to prevent the filtering out of the representation of the object from the first radar frame when the detection corresponding to the object is outside the set interval.

[0050] For further details and options regarding the functionality of device 300, please refer to the information on... Figure 1a and Figure 1b The description details the actions and options of method 100.

[0051] Figure 4 A block diagram is shown relating to an embodiment of a device 400 for adaptively filtering out representations of objects from a first radar frame of a plurality of radar frames captured by a radar device.

[0052] Device 400 includes circuitry 410. Circuitry 410 is configured to perform the functions of device 400. Circuitry 410 may include processor 412, such as a central processing unit (CPU), graphics processing unit (GPU), tensor processing unit (TPU), microcontroller, or microprocessor. Processor 412 is configured to execute program code. The program code may, for example, be configured to perform the functions of device 400.

[0053] Device 400 may further include memory 420. Memory 420 may be one or more of a buffer, flash memory, hard disk drive, removable media, volatile memory, non-volatile memory, random access memory (RAM), or other suitable devices. In a typical arrangement, memory 420 may include non-volatile memory for long-term data storage and volatile memory that functions as device memory for circuit 410. Memory 420 may exchange data with circuit 410 via a data bus. Additional control lines and address buses may also exist between memory 420 and circuit 410.

[0054] The functionality of device 400 can be manifested in the form of executable logic routines (e.g., lines of code, software programs, etc.) stored on a non-transitory computer-readable medium (e.g., memory 420) of device 400 and executed by circuitry 410 (e.g., using processor 412). Furthermore, the functionality of device 400 can be a standalone software application or part of a software application that performs additional tasks related to device 400. The described functionality can be considered as a method configured to be executed, for example, by the processing unit of processor 412 of circuitry 410. Moreover, although the described functionality can be implemented in software, such functionality can also be implemented via dedicated hardware or firmware, or certain combinations of hardware, firmware, and / or software.

[0055] Circuit 410 is configured to perform a first acquisition function 431, a second acquisition function 432, a receiving function 433, a generating function 434, a first determining function 435, and a second determining function 436 for each of a plurality of radar frames. Circuit 410 is further configured to perform a calculation function 438 and a filtering function 439.

[0056] The first acquisition function 431 is configured to acquire the maximum signal strength at zero velocity in the range Doppler representation of a set of radar frames captured by the radar device during a time period prior to the radar frame, including a range bin corresponding to the object. The time period includes at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device. The second acquisition function 432 is configured to acquire a motion vector representing the amplitude and direction of a determined motion of the radar device due to the oscillating motion of the radar device. The receiving function 433 is configured to receive radar frames captured by the radar device having a determined amplitude and direction of motion. The generating function 434 is configured to generate a range Doppler representation of the radar frames. The first determining function 435 is configured to determine a direction vector representing the direction from the radar device to the object. The second determining function 436 is configured to determine the radial relative velocity between the object and the radar device based on the determined motion vector and the determined direction vector. The setting function 437 is configured to set an interval around the determined radial relative velocity for the range bin corresponding to the object in the range Doppler representation, based on the determined radial relative velocity and the determined maximum signal strength. The circuit is further configured to perform calculation function 438 and filtering function 439. Calculation function 438 is configured to calculate the average value of the common interval as the interval between multiple radar frames. Filtering function 439 is configured to filter out the representation of the object from the first radar frame if the detection corresponding to the object is within the common interval in the range bin of the range Doppler representation of the first radar frame, and to prevent the filtering out of the representation of the object from the first radar frame if the detection corresponding to the object is outside the common interval in the range bin of the range Doppler representation of the first radar frame.

[0057] For further details and options regarding the functionality of device 400, please refer to the information on... Figure 1a and Figure 1b Method 100 described and about Figure 2a and Figure 2b The description details the actions and options corresponding to method 200.

[0058] Those skilled in the art will recognize that the present invention is not limited to the embodiments described above. Instead, many modifications and variations can be made within the scope of the appended claims. By studying the drawings, the disclosure, and the appended claims, those skilled in the art will be able to understand and implement these modifications and variations in practicing the claimed invention.

Claims

1. A method for adaptively filtering out representations of objects from radar frames captured by a radar device, the method comprising: The maximum signal strength at zero velocity is obtained in the range Doppler representation of a set of radar frames captured by the radar device during a time period prior to the radar frame, including the detection of the object in the range chamber, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device. Obtain a motion vector representing the amplitude and direction of a determined motion of the radar device caused by the oscillating motion of the radar device; Receive the radar frame captured by the radar device having the amplitude and direction of the acquired motion; Generate the range Doppler representation of the radar frame; Determine the direction vector representing the direction from the radar device to the object; The radial relative velocity between the object and the radar device is determined based on the acquired motion vector and the determined direction vector. For the range Doppler representation including the detected range bin corresponding to the object, an interval is set around the determined radial relative velocity of the object based on the determined radial relative velocity and the determined maximum signal strength; Under the condition that the detection corresponding to the object is within the set interval, the representation of the object is filtered out from the radar frame; as well as If the detection corresponding to the object is located outside the set interval, the filtering of the representation of the object from the radar frame is prevented.

2. The method according to claim 1, wherein, The actions to obtain the maximum signal strength at zero velocity include: Receive a set of radar frames captured by the radar device during a time period preceding the radar frames, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device; The range Doppler representation that generated this set of radar frames; In each range Doppler representation, the signal strength at zero velocity is determined in the range chamber corresponding to the detected object; and The maximum signal strength is determined to be the maximum value of the determined signal strength.

3. A method for adaptively filtering out representations of objects from a first radar frame of a plurality of radar frames captured by a radar device, the method comprising: For each of the plurality of radar frames: The maximum signal strength at zero velocity is obtained in the range Doppler representation of a set of radar frames captured by the radar device during a time period prior to the first radar frame, including the detection of the object in the range chamber, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device. Obtain a motion vector representing the amplitude and direction of a determined motion of the radar device caused by the oscillating motion of the radar device; Receive the radar frame captured by the radar device having the determined amplitude and direction of motion; Generate the range Doppler representation of the radar frame; Determine a direction vector representing the direction from the radar device to the detected object; The radial relative velocity between the object and the radar device is determined based on the determined motion vector and the determined direction vector; as well as For the range Doppler representation including the detected range bin corresponding to the object, an interval is set around the determined radial relative velocity of the object based on the determined radial relative velocity and the determined maximum signal strength; Calculate the common interval as the average of the intervals set for the plurality of radar frames; Under the condition that the detection corresponding to the object is located within the calculated common interval in the range bin of the range Doppler representation of the first radar frame, the representation of the object is filtered out from the first radar frame; as well as If the detection corresponding to the object is located outside the calculated common interval in the range bin of the range Doppler representation of the first radar frame, the filtering of the representation of the object from the first radar frame is prevented.

4. The method according to claim 3, wherein, The oscillating motion of the radar device is due to the oscillating motion of the support structure on which the radar device is mounted.

5. A non-transitory computer-readable storage medium having instructions stored thereon for implementing the method according to claim 1 when executed by a processing-capable device.

6. An apparatus for adaptively filtering out representations of objects from radar frames captured by a radar device, the apparatus comprising circuitry configured to perform: The first acquisition function is configured to acquire the maximum signal strength at zero velocity in a range Doppler representation of a set of radar frames captured by the radar device during a time period prior to the radar frame, including a range bin containing a detection corresponding to the object, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device. The second acquisition function is configured to acquire a motion vector representing the amplitude and direction of a determined motion of the radar device caused by the oscillating motion of the radar device; The receiving function is configured to receive the radar frames captured by the radar device having the determined amplitude and direction of motion; The generation function is configured to generate a range Doppler representation of the radar frame; The first determining function is configured to determine a direction vector representing the direction from the radar device to the object; The second determining function is configured to determine the radial relative velocity between the object and the radar device based on the acquired motion vector and the determined direction vector; The setting function is configured to, for the range bins in the range Doppler representation including the detected range bins corresponding to the object, set an interval around the determined radial relative velocity of the object based on the determined radial relative velocity and the determined maximum signal strength; The filtering function is configured as follows: Under the condition that the detection corresponding to the object is within the set interval, the representation of the object is filtered out from the radar frame; as well as If the detection corresponding to the object is located outside the set interval, the filtering of the representation of the object from the radar frame is prevented.

7. The apparatus according to claim 6, wherein, The first acquisition function is configured as follows: Receive a set of radar frames captured by the radar device during a time period preceding the radar frames, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device; The range Doppler representation that generated this set of radar frames; The signal strength at zero velocity is determined in the range chamber corresponding to the detection in each range Doppler representation; as well as The maximum signal strength is determined to be the maximum value of the determined signal strength.

8. An apparatus for adaptively filtering out representations of objects from a first radar frame of a plurality of radar frames captured by a radar device, the apparatus comprising circuitry configured to perform: For each of the plurality of radar frames: The first acquisition function is configured to acquire the maximum signal strength at zero velocity in a range Doppler representation of a set of radar frames captured by the radar device during a time period prior to the first radar frame, including a range bin containing a detection corresponding to the object, the time period including at least one cycle of the oscillating motion of the radar device relative to a stationary object in the scene monitored by the radar device. The second acquisition function is configured to acquire and receive a motion vector representing the amplitude and direction of a determined motion of the radar device caused by the oscillating motion of the radar device; The receiving function is configured to receive the radar frames captured by the radar device having the determined amplitude and direction of motion; The generation function is configured to generate a range Doppler representation of the radar frame; The first determining function is configured to determine a direction vector representing the direction from the radar device to the detected object; The second determining function is configured to determine the radial relative velocity between the object and the radar device based on the determined motion vector and the determined direction vector; as well as The setting function is configured to, for the range doppler representation including the detection of the object, set an interval around the determined radial relative velocity of the object based on the determined radial relative velocity and the determined maximum signal strength; The circuit is further configured to perform: The calculation function is configured to calculate a common interval as the average of the intervals set for the plurality of radar frames; and The filtering function is configured as follows: Under the condition that the detection corresponding to the object is located within the calculated common interval in the range bin of the range Doppler representation of the first radar frame, the representation of the object is filtered out from the first radar frame; as well as Under the condition that the detection corresponding to the object is located outside the calculated common interval in the range bin of the range Doppler representation of the first radar frame, the filtering of the representation of the object from the first radar frame is stopped.

9. The apparatus according to claim 8, wherein, The oscillating motion of the radar device is due to the oscillating motion of the support structure on which the radar device is mounted.

Images