The invention relates to a method and an arrangement for detecting acoustic and optical information as well as a corresponding computer program and a corresponding computer-readable storage medium, which can in particular be used to generate three-dimensional sound maps. The sound maps can be visualized and provided with information about acoustic sources, sound power and emitter characteristics. For this purpose, it is proposed to use for the detection of acoustic and optical information at least one microphone array and at least one device for detecting optical geometry data, wherein the at least one microphone array and the at least one device for detecting optical geometry data are arranged in a defined positional relationship. Acoustic information emitted from an object and the geometry of the object are detected by moving the at least one microphone array, the at least one device for detecting optical geometry data and the object relative to each other.

Optical fiber based acoustic sensors are provided herein. The optical fiber based acoustic sensors described herein include acoustically responsive optical structures configured to detect and receive acoustic signals, including ultrasound signals, and provide associated optical signals to a system for processing and interpretation to implement tracking, location, and imaging capabilities. Optical fiber based sensors provided herein may be disposed at ends of or along the length of optic fibers. Optical fiber based sensors may be included within various devices, including, for example, medical devices.

A laboratory system has demonstrated the measurement of three degrees of vibrational freedom simultaneously using a single beam through heterodyne speckle imaging. The random interference pattern generated by the illumination of a rough surface with coherent light can be exploited to extract information about the surface motion. The optical speckle pattern is heterodyne mixed with a coherent reference. The recorded optical data is then processed to extract three dimensions of surface motion. Axial velocity is measured by demodulating the received time-varying intensity of high amplitude pixels. Tilt, a gradient of surface velocity, is calculated by measuring speckle translation following reconstruction of the speckle pattern from the mixed signal.

A method for detecting a defect in a structure member includes exciting a structure member by applying an excitation signal to the structure member, applying an optical signal to the excited structure member and capturing a reflected optical signal formed by a reflection of the applied optical signal by the excited structure member, and processing the reflected optical signal to determine one or more defects in the structure member.

A light imaging system for an acoustic imaging system uses polarized light to illuminate a birefringent detector through a partially transparent mirror, a lens through which light reflected from the detector passes and a light imager views the mirror through a linear polarizer with the position of the light imager being adjusted to image the full detector and to minimize effects due to the non-linear behavior of the detector.

A calibration apparatus for calibrating a laser Doppler vibrometer includes: a frequency shifter stage that: receives, from the laser Doppler vibrometer, primary laser light; produces frequency shifted light; communicates the frequency shifted light to a reflector; receives frequency shifted light reflected by the reflector; produces secondary light; and communicates the secondary light to the laser Doppler vibrometer, such that the laser Doppler vibrometer receives the secondary light from the frequency shifter stage and produces a synthetic velocity shift from the secondary light; and the reflector that receives and reflects the frequency shifted light back to the frequency shifter stage.

A laboratory system has demonstrated the measurement of three degrees of vibrational freedom simultaneously using a single beam through heterodyne speckle imaging. The random interference pattern generated by the illumination of a rough surface with coherent light can be exploited to extract information about the surface motion. The optical speckle pattern is heterodyne mixed with a coherent reference. The recorded optical data is then processed to extract three dimensions of surface motion. Axial velocity is measured by demodulating the received time-varying intensity of high amplitude pixels. Tilt, a gradient of surface velocity, is calculated by measuring speckle translation following reconstruction of the speckle pattern from the mixed signal.

A part (120) may be subjected to both a resonance inspection and a surface vibration inspection. Various protocols (230; 240; 250; 280; 260) are disclosed as to how the results of one or more of these inspections may be used to evaluate the part (120).

A method is described for automatically detecting shear-wave (S-wave) microseismic reflections using distributed acoustic sensing (DAS). The method includes obtaining raw DAS data; performing passive seismic event detection and phase picking; extracting a passive seismic event based on the passive seismic event phase picks to generate a seismic S-wave event gather; reducing noise in the raw DAS data; using the passive seismic S-wave event gather and the passive seismic event phases to identify an apex of a passive seismic S-wave event in the denoised DAS dataset and dividing it into two portions based on the apex; dip filtering the two portions to remove the direct arrival of the passive seismic S-wave events to generate a dip-filtered gather; and generating an S-wave microseismic reflection gather based on the dip-filtered gather.

A method of forming a vapour deposited polymeric conformal coating on a surface of a part (23). The method comprises placing the part (23) and a flow control screen in a deposition chamber (22); dispersing a gas into the chamber (22) from which the polymeric coating is deposited on the surface. The flow control screen is spaced apart from the surface and is configured to control a localised flow of the gas in the chamber so as to impose a structure on the deposited coating.