Provided are a sonar system and transducer assembly for producing a 3D image of an underwater environment. The sonar system may include a housing mountable to a watercraft having a transmit transducer that may transmit sonar pulses into the water. The system may include at least one sidescan transducer array in the housing that receives first and second sonar returns with first and second transducer elements and converts the first and second returns into first and second sonar return data. A sonar signal processor may then generate a 3D mesh data using the first and second sonar return data and at least a predetermined distance between the transducer elements. An associated method of using the sonar system is also provided.

In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler radars to help improve driving safety, no matter human-driven or auto-driven, if the radars use same frequency band, avoiding interference between them is a hard task. Assigning distinct frequencies is one of the solutions, however not only it wastes expensive spectrum resource, but also the task itself to dynamically assign frequency to vehicles randomly come together becomes a hard one to do. The disclosed invention of Doppler group radar will allow radar devices to work together using shared frequency band without interfering one another, without sacrificing performance, and without much increase in costs.

A plurality of control points (10) are defined which each have a known spatial relationship relative to an array of transducers. An amplitude is assigned to each control point (12). A matrix (16) is produced containing elements which represent, for each of the control points, the effect that producing a modeled acoustic field having the assigned amplitude with a particular phase at the control point has on the consequential amplitude and phase of the modeled acoustic field at the other control points (14). Eigenvectors of the matrix (18) are determined, each eigenvector representing a set of phases and relative amplitudes of the modeled acoustic field at the control points. One of the sets (20) is selected and the transducer array is operated to cause one or more of the transducers to output an acoustic wave each having an initial amplitude and phase such that the phases and amplitudes of the resultant acoustic field at the control points correspond to the phases and relative amplitudes of the selected set (22, 24).

A method for determining the elevation angle and/or azimuth angle of a signal received by an ultrasound sensor includes: providing an ultrasound sensor with a frequency-dependent radiation pattern; transmitting a first ultrasound wave at a first frequency; transmitting a second ultrasound wave at a second frequency different from the first frequency; receiving reflections of the first and second waves, the reflections being caused by an object; and determining the elevation angle of the first and second reflected waves based on amplitudes of the reflections of the first and second waves. Determining the elevation angle (and/or azimuth angle includes calculating a ratio between the amplitudes of received reflections of the first and second waves and mapping a calculated ratio to an elevation angle and/or azimuth angle. The mapping is based on a predetermined ratio curve or ratio dataset which associates a certain amplitude ratio to an elevation angle and/or azimuth angle.

Techniques and apparatuses are described that implement face authentication anti-spoofing using ultrasound. In particular, a face-authentication system uses ultrasound to distinguish between a real human face and a presentation attack that uses instruments to present a version of a human face. The face-authentication system includes or communicates with an ultrasonic sensor, which can detect a presentation attack and notify the face-authentication system. In general, the ultrasonic sensor analyzes characteristics of a presented object and determines whether the object represents a human face or a presentation attack instrument. In this way, the ultrasonic sensor can prevent unauthorized actors from using the presentation attack to gain access to a user's account or information.

Techniques and apparatuses are described that implement face authentication anti-spoofing using interferometry-based coherence. In particular, a face-authentication system uses ultrasound to distinguish between a real human face and a presentation attack that uses instruments to present a version of a human face. The face-authentication system includes or communicates with an ultrasonic sensor, which can detect a presentation attack and notify the face-authentication system. In general, the ultrasonic sensor uses interferometry to evaluate an amount of coherence (or similarity) between reflections observed by two or more transducers. In this way, the ultrasonic sensor can prevent unauthorized actors from using the presentation attack to gain access to a user's account or information.

Techniques and apparatuses are described that implement face authentication anti-spoofing using ultrasound. In particular, a face-authentication system uses ultrasound to distinguish between a real human face and a presentation attack that uses instruments to present a version of a human face. The face-authentication system includes or communicates with an ultrasonic sensor, which can detect a presentation attack and notify the face-authentication system. In general, the ultrasonic sensor uses power-spectra to evaluate an amount of variance observed over time within at least one receive channel. In this way, the ultrasonic sensor can prevent unauthorized actors from using the presentation attack to gain access to a user's account or information.

A method, device and computer program product for controlling the device by tracking a movement of a hand or other objects. The device receives acoustic signals. At least a portion of the received signals are transformed into two-dimensional sinusoids whose frequencies are proportional to an angle-of-arrival (AoA) and a propagation distance of the reflected signals. An AoA-distance profile is derived based on signals received from the object by evaluating frequencies of the two-dimensional sinusoids. Then, an AoA-distance pair is derived from the AoA-distance profile. A current location of the object is determined based on the estimated AoA-distance pair. The device then performs a command in response to detecting that the user moved to perform the command based on prior and current locations of the object.

Apparatus and methods for enhanced wireless determination of a position and direction of a smart device are describe which support the display of a virtual tag upon a user interface of the smart device. Wireless transceivers controlled by the smart device communicate with reference point transceivers to generate data sufficient to determine relative positions of the wireless transceivers and a direction of interest. Operation of LIDAR may be operative to verify the position and direction of the Smart Device as well as a topography of the environment.

Disclosed is a LADCP and USBL combined observation device and a use method thereof. The device includes a cable winch system, a mounting frame, a LADCP system, a USBL beacon and a correction system. The LADCP system, the USBL beacon and the correction system can be mounted to the mounting frame by adopting a hardware support platform. The cable winch system can drive the LADCP system to deploy or recover along a vertical section. The LADCP system is used to obtain the current velocity of a single small profile, and the USBL beacon can locate the underwater position information, and the correction system can obtain data information in the seawater where the mounting frame is located, so as to calculate an absolute current velocity according to the velocity obtained by the LADCP system and the current data obtained by the correction system.