An apparatus and method for generating high quality, high frame rate images in a handheld or hand-carried ultrasound imaging machine. The apparatus includes a time-multiplexed beamformer coefficient generator that supplies the necessary delay and weight coefficients to process multiple beams in parallel via a beamforming coefficient bus. This approach reduces the required hardware and power consumption to satisfy the physical space and power requirements of a handheld probe. The ultrasound machine may optionally turn off or operate beamformers in a standby mode. The ultrasound machine may also use pulse inversion harmonics to improve image quality by improving signal-to-noise ratio.

A method for object tracking is presented based on the similarity of waveforms recorded at the receiving elements of the array. A rectangular array of acoustic transducers is divided into four quadrants, on the basis that each quadrant contains a receiving element in its center. Each of the four recorded waveforms are compared against each of the remaining waveforms to identify either absolute similarity of the signal characteristics, which would denote absence of the object, or identifying a waveform being the least similar from the rest, hence pointing to a part of the array above which the object is located. Further, source localization algorithms are used for ill-posed scenarios where the distance between receivers is on the same order of magnitude of the dimensions of the tracked object and of the tracking distances.

Producing multiple independent fields from many phased acoustic transducers represents a difficult computational problem. By first dividing up each field to its own group of transducers and then treating each group as an element with adjustable phase, one can minimize the field-to-field interference through a power iteration solution. These solutions can be further refined by including tracking information from users in the space and how they shadow or reflect the acoustic fields.

A method for specifying desired quantities of the energy flux of the combined waves of acoustic radiation pressure to apply producing a mid-air haptic pushing force, which has the effect of simultaneously reducing the harmonic distortion present is described. Further, a method for communicating only the summaries of acoustic field contributions at the required locations in the form of summed portions of the relatively small matrix whose row and column count depend only on the control point count is described. Further, phased arrays of ultrasonic speakers can produce a relatively large amount of acoustic energy which is usually directed in a specific direction or focused to a particular point depending on the application of the array. Further, to allow the system to be driven more strongly than usual, the complex-valued linear system that governs the drive signal to each control point is solved twice. Further, to achieve mid-air haptics with high precision the radiation pressure generated must be modelled accurately.

Techniques, systems, and devices are disclosed for synthetic aperture ultrasound imaging using a beamformer that incorporates a model of the object. In some aspects, a system includes an array of transducers to transmit and/or receive acoustic signals at an object that forms a synthetic aperture of the system with the object, an object beamformer unit to (i) beamform the object coherently as a function of position, orientation, and/or geometry of the transducers with respect to a model of the object, and (ii) produce a beamformed output signal including spatial information about the object derived from beamforming the acoustic echoes; a data processing unit to process data and produce an image of the object based on a rendition of the position, the orientation, the geometry, and/or the surface properties of the object, relative to the coordinate system of the array, as determined by the data processing unit.

Two methods for rendering haptic surfaces through spatial modulation of ultrasound are described: Singular Value Decomposition (SVD) with Tikhonov Regularization and Mini-Batch, Stochastic Gradient Descent with Momentum (MSGDM). Further, adjustment in the placement of transducers, arrays can be generated which allow for variable focus points using a limited set of driving signals. This is accomplished by generating a set of mutually-exclusive transducer placement layouts which when driven together produce a set of sufficiently orthogonal fields at various points of interest. Further, using basic transformations on sampling locations a field can be translated or rotated in 3-dimensional space. This enables the creation of spatiotemporal modulated haptics with reduced computation. Further, mid-air haptics using ultrasound can be generated via amplitude modulation or via spatial modulation of control points defined at spatial locations in an acoustic field above a phased array device.

A programmable metasurface and method is described having a plurality of parallel slits in an elastic substrate plate defining a plurality of unit cells, each having an actuator beam and a sensing beam with a slit therebetween. Each sensing beam has a pair of sensors for sensing flexural waves in the substrate. The actuator beam has a piezoelectric actuator that is controlled by a control circuit where the control circuit generates an actuator signal and where the control circuit compares the preceding actuator signal to the difference between the sensors and an electrical transfer function to result in the metasurface being able to perform a desired function.

Disclosed herein are ultrasonic transducer systems comprising: an ultrasonic imager comprising a plurality of pMUT transducer elements; and one or more circuitries connected electronically to the plurality of transducer element, the one or more circuitries configured to enable: pulse transmission and reception of reflected signal for the ultrasonic transducer; and control of the ultrasonic transducer, the control of the ultrasonic transducer comprising focusing ultrasonic beam in an elevation direction.

A method for providing a broadband constant beam pattern acoustic array includes providing an array of transducers in a known three dimensional axisymmetric spherical configuration with each transducer element having an associated signal. A user can specify a far field beam pattern for the array. Weightings are calculated for each transducer in the array as being proportional to the voltage that gives the beam pattern power level associated with the bearing for each transducer. Signal power levels for each transducer are modified in accordance with the weightings. The array can be operated for receiving and transmitting signals with a constant beam pattern over a broad range of frequencies.

Provided is a sound image reproduction device, sound image reproduction method, and sound image reproduction program that can support monaural sound sources and is capable of imparting directivity to virtual sound sources in a space. An acoustic signal processing device (sound image reproduction device) 1 that generates virtual sound sources in a space using multiple loudspeakers arranged in a straight line, includes: a focal-point position determination unit 12 that determines the position of each virtual sound source to generate multiple virtual sound sources in a circular arrangement; a filter-coefficient determination unit 13 that calculates an impulse response vector for each loudspeaker by performing an inverse Fourier transform on a driving function for each loudspeaker that is used to generate a virtual sound source at the position of each virtual sound source and in which different weights are given to some of the virtual sound sources; and a convolution calculation unit 14 that calculates the convolution of one inputted acoustic signal with the impulse response vector for each loudspeaker and outputs each acoustic signal to the corresponding the multiple loudspeakers.