Multistatic radar systems and associated methods are disclosed herein. In some embodiments, a multistatic radar system can include multiple radar transmitters and multiple radar receivers. The transmitters are configured to generate radio-frequency (RF) signals in a target volume, and the receivers are configured to receive the RF signals after the RF signals are reflected off an object moving through the target volume. The transmitters and the receivers can be spaced apart and aperiodically positioned about the target volume. The receivers can sample and digitize the reflected RF signals at an RF frequency. The radar system further includes a processing device configured to determine a property of the object based on the sampled reflected RF signals.

Disclosed are systems and techniques for detecting user presence, user motion, and for performing facial authentication. For instance, a wireless device can receive a waveform that is a reflection of a transmitted radio frequency (RF) waveform. Based on RF sensing data associated with the received waveform, the wireless device can determine a presence of a user. In response to determining the presence of the user, the wireless device can initiate facial authentication of the user.

A system includes a database, a camera, a tracking arrangement, and a processing arrangement. The database stores profiles including visual profiles of a plurality of sports players, each visual profile comprising identifying information for a player, each profile comprising an associated playerID. The camera captures a video stream comprising images of the sports players. The tracking arrangement captures data corresponding to trajectories of sports balls launched by the sports players. The processing arrangement coupled to the database. The camera and the tracking arrangement configured to; detect a first sports player in an image from the video stream and determine visual characteristics of the first detected sports player; match the determined visual characteristics to a first visual profile of a first profile and an associated first playerID stored in the database; and associate a first trajectory associated with a first sports shot with the first playerID.

A system includes a camera capturing images in a first field of view of a sports ball bouncing and rolling, a storage arrangement, and a processing arrangement. The storage arrangement includes a three-dimensional 3D model of a part of a sports play area and the processing arrangement is configured to: detect a pixel location of a ball in an image; determine, based on intrinsic and extrinsic calibration parameters, a camera-ball line comprising a straight line passing through the camera in the direction of the sports ball and to determine, based on the 3D model, an intersection point of the camera-ball line with the 3D model. The processor outputs the intersection point as a 3D position of the ball in the image.

A processor and camera capture data corresponding to a position of a ball and automatically adjust orientation and zoom level of the camera. The processor pre-calibrates the camera so an initial orientation is known in a world coordinate system (WCS) and so different zoom levels are associated with respective parameter values. A first position of the ball in a first image is detected and a first zoom level of the first image and intrinsic parameter values for the first zoom level are read. Based on pan and tilt relative to the initial orientation, the first orientation of the camera is determined. A 3D line through the camera and the ball in WCS is determined based on the first position, the first orientation and parameter values for the first zoom level and a 3D position is determined in WCS along the line based on information extrinsic to the camera.

A system includes a database, a tracking arrangement, a motion sensor device and a processing arrangement. The database stores profiles for each sports player, each profile comprising identifying information for the player and a playerID. The tracking arrangement captures shot data corresponding to trajectories of sports balls launched by the players. The motion sensor device captures motion data corresponding to a swinging motion of a player or ball striking implement. The tracking arrangement and the motion sensor device: detect a first swing of a first player from the motion data captured by the motion sensor device, the first player being associated with a first playerID; associate the first swing of the first player with a timestamp and a location; and associate a first trajectory of a sports ball from the shot data captured by the tracking arrangement to the first swing based on the timestamp and the location.

In a method for mitigating the blurring effect in a radar image (40) obtained by a ground-based radar system, thereof, a Pulse Repetition Frequency (PRF) value is selected (110) in a radar sensor unit (30) such that radial velocity measurements of the targets of an observed scenario can be made up to a maximum unambiguous velocity v.sub.max, a radial velocity threshold is also selected (101) to discriminate between substantially stationary targets and possible fast-moving targets having radial velocities v.sub.R, j≤v* and v.sub.R, f>v*, respectively. The scenario is conventionally scanned (120) by emitting transmission signals to the targets and receiving corresponding backscattered signals (23) from which raw data (25) are extracted (130), the latter in turn are Doppler-processed (140) so as to discriminate first and second data (31, 32) related to the substantially stationary and to the fast-moving target(s), respectively, according to whether the measured radial velocities (v.sub.R) are lower than the radial velocity threshold (v*) or not, respectively; second data are removed (150) from the Doppler-processed data (27) and radar image (40) is formed from remaining first data, i.e., based on the substantially stationary targets only. The method allows reducing the occurrence of artifacts due to fast-moving objects that are systematically present or that turn up in the scenario at the moment of taking an image thereof, such as truckloads or vehicle in general, as well as crane mobile portion in scenarios like a portion of a mine. (FIG. 11).

In an embodiment, a method for completing measurements for a uniform linear array from measurements from a sparse linear array is provided. The method includes: receiving a first set of measurements for a sparse linear array by a computing device; generating a second set of measurements for a uniform linear array from the first set of measurements by the computing device; and using matrix completion to determine values for a plurality of missing elements of the generated second set of measurements for the uniform linear array by the computing device.

The methods and device disclosed herein provide an array such as a Radio Frequency (FR) antenna array for measuring the array movement or displacement of the array relative to a reference location. In some cases the array may be attached to or in communication with the device. The array comprises at least two transducers (e.g. RF antennas), wherein at least one of the at least two transducers is configured to transmit a signal towards the object, and at least one transceiver attached to said at least two transducers, the at least one transceiver is configured to repetitively transmit at least one signal toward an object and receive a plurality of signals affected or reflected while the array is moved in proximity to the object/medium or scene; and at least one processor unit, configured to: process the affected signals to yield a plurality of signal measurements and compare said signal measurements obtained at different locations over time of said second object and calculate a movement of the object relative to a reference location.

In a method for the recognition of an object by means of a radar sensor system, a primary radar signal is transmitted into an observation space, a secondary radar signal reflected by the object is received, a Micro-Doppler spectrogram of the secondary radar signal is generated, and at least one periodicity quantity relating to an at least essentially periodic motion of a part of the object is determined based on the Micro-Doppler spectrogram. The determining of the at least one periodicity quantity includes the following steps: (i) determining the course of at least one periodic signal component corresponding to an at least essentially periodic pattern of the Micro-Doppler spectrogram, (ii) fitting a smoothed curve to the periodic signal component, (iii) determining the positions of a plurality of peaks and/or valleys of the smoothed curve, and (iv) determining the periodicity quantity based on the determined positions of peaks and/or valleys.