An acoustic system and method is disclosed for providing spatial and temporal classification of a range of different types of sound producing targets in a geographical area. The system includes an optical signal transmitter arrangement for repeatedly transmitting, at multiple instants, interrogating optical signals into each of one or more optical fibres distributed across the geographical area and forming at least part of an installed fibre-optic communications network. An optical signal detector arrangement receives, during an observation period following each of the multiple instants, returning optical signals scattered in a distributed manner over distance along the one or more of optical fibres. A processing unit demodulates acoustic data from the optical signals, processes the acoustic data and classifies it in accordance with the target classes or types to generate a plurality of datasets including classification, temporal and location-related data, and a storage unit stores the datasets in parallel with raw acoustic or optical data which is time and location stamped so that it can be retrieved for further processing.

Some embodiments are directed to a system for measuring vibrations of a surface of a mechanical part, by digital holography. The system includes a source of radiation emitting in a predetermined range of frequencies, a first separator element configured to define a first incident ray and a reference ray, a module for shaping a second incident ray from the first incident ray, and an optical element configured to make the reference ray and a radiation produced by a reflection of the incident ray on the surface of the mechanical part interfere. The module for shaping the second incident ray includes diffracting optical elements having a diffraction structure to diffract the incident radiation. The structure is from a polymer, sol-gel or photoresin material resting against a glass substrate, the structure including elements etched in a plane parallel and/or orthogonal to the substrate, with dimensions from 100 nanometres to 100 micrometres.

A system includes at least one earpiece wherein each earpiece comprises an earpiece housing, a light source operatively connected to each earpiece housing and configured to transmit substantially coherent light toward an outer surface of a user's body, a light receiver operatively connected to the earpiece housing proximate to the light source and configured to receive reflected light from the outer surface of the user's body, and one or more processors disposed within the earpiece housing and operatively connected to the light source and light receiver, wherein one or more processors is configured to determine bone vibration measurements from the reflected light. A method of determining bone vibrations includes providing at least one earpiece, transmitting substantially coherent light toward an outer surface of a user's body using the earpiece, receiving reflected light from the outer surface of the user's body using the earpiece, and determining bone vibration measurements using the earpiece.

Techniques of measuring vibrations from an object surface using LIDAR includes grouping beams having similar vibration velocity values over a specified time window and replace outlier vibration velocity values with a vibration velocity value based on the similar vibration velocity values over the specified time window. Advantageously, replacing outlier vibration velocity values with a value based on vibration velocity values of similar beams results in a more accurate profile of the vibration velocity field over the surface.

Systems and methods for improving spectral-shift methods for calculating acoustic attenuation coefficients are disclosed. Systems, methods, and apparatuses for transmitting ultrasound pulse sequences for improved signal-to-noise outside the main passband of ultrasound transducers are disclosed. Systems, methods, and apparatuses for using the echoes from the transmitted pulse sequences to calculate the attenuation coefficient are disclosed.

Systems and methods are provided, which use at least two coherent light sources with known phase relations between them, which are configured to illuminate a target with at least two corresponding spots, an optical unit comprising a mask and configured to focus, onto a sensor, interfered scattered illumination from the spots of the target, passing through the mask, to yield a signal, at least one shifter configured to shift a frequency of at least one of the coherent light sources to provide a carrier frequency in the signal, and a processing unit configured to derive a vibration frequency of the target from the sensor signal with respect to the carrier frequency. The vibration frequency of the target is separated from the carrier frequency and speckle disturbances may be attenuated or avoided.

An acoustic system and method is disclosed for providing spatial and temporal classification of a range of different types of sound producing targets in a geographical area. The system includes an optical signal transmitter arrangement for repeatedly transmitting, at multiple instants, interrogating optical signals into each of one or more optical fibres distributed across the geographical area and forming at least part of an installed fibre-optic communications network. An optical signal detector arrangement receives, during an observation period following each of the multiple instants, returning optical signals scattered in a distributed manner over distance along the one or more of optical fibres. A processing unit demodulates acoustic data from the optical signals, processes the acoustic data and classifies it in accordance with the target classes or types to generate a plurality of datasets including classification, temporal and location-related data, and a storage unit stores the datasets in parallel with raw acoustic or optical data which is time and location stamped so that it can be retrieved for further processing.

A system for near-surface subsurface imaging for detecting and characterizing subsurface heterogeneities comprises a non-contact acoustic source that senses a plurality of acoustic waves that travel through a surface; an instrument that outputs probing electromagnetic signals through the surface that interact and are affected by scattered signals of the acoustic waves and further senses vibrational modes of a subsurface below the surface; an imaging device that dynamically generates a time sequence of images of properties of the acoustic waves and maps elastic wave fields of the acoustic waves; and a processor that analyzes dynamic multi-wave data of the images to quantify spatial variations in the mechanical and viscoelastic properties of the subsurface.

A system for measuring vibrations of a surface (VSURF) of a mechanical part (M), comprising a source (SOURCE) of radiation (L), a first separator element (ELI) configured to define a first incident ray (LB1) and a reference ray (RLB), a shaping module (DOEM) producing a second incident ray (LB2) from said first incident ray (LB1), and an optical element (OE) capable of an interferential addition of the reference ray (RLB) and a ray produced by a reflection of said second incident ray (LB2) on said surface (VSURF), the shaping module (DOEM) comprising one or more diffracting optical elements (DOE1, . . . , DOEn), each comprising at least one diffraction structure (FSTRUCT) diffracting all or part of the first incident ray (LB1) so as to illuminate a chosen surface of the mechanical part.

The present disclosure generally relates to systems and methods for imaging and sensing vibrations of an object. In one implementation, a system is provided for detecting vibrations that comprises a sensor with a plurality of pixels, each pixel including at least one photosensitive element. The sensor is configured to output signals related to illumination on each pixel. The system also includes at least one processor configured to receive the output signals from the sensor and detect, based on the output signals, one or more polarities. The at least one processor is also configured to determine timestamps associated with the output signals, analyze the timestamps and the polarities to detect vibrations of an object in the field of view of the sensor, and determine one or more frequencies of the detected vibrations.