Method, device, and system for interference reduction in a frequency-modulated continuous-wave radar unit

    公开(公告)号:US11567167B2

    公开(公告)日:2023-01-31

    申请号:US16596323

    申请日:2019-10-08

    Applicant: Axis AB

    Abstract: A method for interference reduction in a stationary radar unit of a frequency-modulated continuous-wave (FMCW) type is provided. A sequence of beat signals is received, and a reference beat signal is calculated as an average or a median of one or more of the beat signals in the sequence. By comparing a difference between a beat signal and the reference beat signal, or a derivative of the difference, to one or more thresholds, a segment which is subject to interference is identified. The segment of the beat signal is replaced by one or more of a corresponding segment of an adjacent beat signal in the sequence, and a corresponding segment of the reference beat signal.

    ROTATION INVARIANT OBJECT FEATURE RECOGNITION

    公开(公告)号:US20170169306A1

    公开(公告)日:2017-06-15

    申请号:US14963792

    申请日:2015-12-09

    Applicant: Axis AB

    CPC classification number: G06K9/4647 G06K9/46 G06K9/6202

    Abstract: A method may include determining a value indicative of an average intensity of blocks in an image. The blocks include a primary and outer blocks. Each of the outer blocks may have three, five, or more than five pixels. The image may describe an external pixel lying between the primary and at least one of the outer blocks. The external pixel may not contribute to the value indicative of the average intensity of any of the blocks. The image may also describe a common internal pixel lying within two of the blocks. The common pixel may contribute to the value indicative of the average intensity of the two of the blocks. The method may include comparing the value indicative of the average intensity of the primary block to the values of the outer blocks, and quantifying a feature represented by the image by generating a characteristic number.

    Resolving doppler unambiguity in TDM-MIMO radars based on spatial phase change rate

    公开(公告)号:US12146981B2

    公开(公告)日:2024-11-19

    申请号:US18358215

    申请日:2023-07-25

    Applicant: Axis AB

    Abstract: A TDM MIMO FMCW radar comprises an array of physical receivers with a first spacing in a first direction and a plurality of physical transmitters arranged with a second spacing in said first direction. A virtual array signal of a range-Doppler bin relating to a scene with a moving object is processed by a phase compensation method, which introduces a phase ambiguity between the subarrays. A positive or negative spatial phase change rate with respect to the first direction is computed based on elements of the compensated virtual array signal corresponding to one subarray at a time. From this, based on the spacings, a spatial phase change between a pair of the subarrays is predicted. Next, a residual phase shift between said pair of subarrays is determined by comparing an actual phase shift of the compensated virtual array signal and the predicted spatial phase shift.

    RESOLVING DOPPLER AMBIGUITY IN TDM-MIMO RADARS BASED ON PHASE AT PEAK

    公开(公告)号:US20240103129A1

    公开(公告)日:2024-03-28

    申请号:US18446012

    申请日:2023-08-08

    Applicant: Axis AB

    CPC classification number: G01S7/356 G01S13/36

    Abstract: A TDM MIMO FMCW radar comprises an array of physical receivers with a first spacing in a first direction and a plurality of physical transmitters arranged with a second spacing in said first direction. A virtual array signal of a range-Doppler bin relating to a scene with a moving object is processed by a phase compensation method, which introduces a phase ambiguity between the subarrays. For each of the subarrays, a frequency spectrum is computed of those elements of the compensated virtual array signal which correspond to consecutive virtual antenna elements generated by physical receivers belonging to the same row. Next, an amplitude-peak frequency is identified jointly for the frequency spectra of the subarrays. Next, a residual phase shift between a pair of the subarrays is determined by comparing, at the amplitude-peak frequency, the respective phases of the frequency spectra.

    Rotation invariant object feature recognition

    公开(公告)号:US09830528B2

    公开(公告)日:2017-11-28

    申请号:US14963792

    申请日:2015-12-09

    Applicant: Axis AB

    CPC classification number: G06K9/4647 G06K9/46 G06K9/6202

    Abstract: A method may include determining a value indicative of an average intensity of blocks in an image. The blocks include a primary and outer blocks. Each of the outer blocks may have three, five, or more than five pixels. The image may describe an external pixel lying between the primary and at least one of the outer blocks. The external pixel may not contribute to the value indicative of the average intensity of any of the blocks. The image may also describe a common internal pixel lying within two of the blocks. The common pixel may contribute to the value indicative of the average intensity of the two of the blocks. The method may include comparing the value indicative of the average intensity of the primary block to the values of the outer blocks, and quantifying a feature represented by the image by generating a characteristic number.

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