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.

A device and method for measuring a surface of an object, including at least one light source, at least one optical sensor, and an interferometry device having a measurement arm and a reference arm, the former directing light from each light source towards the surface of the object and directing light from the surface towards each optical sensor; the measurement device, in an interferometry configuration, illuminating the reference arm and the measurement arm with each light source and directing the light from the measurement arm and the reference arm towards each optical sensor to form an interference signal; the measurement device, in an imaging configuration illuminating at least the measurement arm and directing the light from the measurement arm towards the optical sensor to form an image of the surface; the measurement device including a digital processor producing, from the interference signal and the image, information on the surface.

An optical fiber sensing system according to this disclosure includes: a first optical fiber network (10A) configured to detect first sensing information about a monitoring target; a second optical fiber network (10B) configured to detect second sensing information about the monitoring target; a first reception unit (21A) configured to receive a first light signal from the first optical fiber network (10A); a second reception unit (21B) configured to receive a second light signal from the second optical fiber network (10B); and an identification unit (22) configured to identify the monitoring target, based on the first sensing information included in the first light signal, and the second sensing information included in the second light signal.

Described herein is an optical fibre mounting structure (180) for fibre vibration sensing of a distributed system (100) of spaced apart vibration sources (112-131). Mounting structure (180) includes a base portion (200) having a two dimensional surface area defining a vibration surface (202). A mounting apparatus (236) is adapted to mount the base portion (200) to a support structure (e.g. 104) of the distributed system (100) adjacent one of the vibration sources. A fibre engagement structure (e.g. 210-215) is provided for supportively engaging a length (218) of optical fibre in contact with the vibration surface (202).

An acoustic sensor that uses an optical fiber and has a high directivity is provided. An acoustic sensor includes a sensing part and an interrogator. The sensing part has a sensing element composed of an optical fiber. The interrogator is connected to the sensing part, sends a pulse light P to the sensing part, and detects an acoustic wave sensed by the sensing part based on a reflected return light from the sensing part. The sensing element is composed of the optical fiber folded in such a way that it reciprocates a plurality of number of times along a directivity direction in which directional sensitivity is exhibited.

To apply an optical amplification repeater device to optical fiber sensing to lengthen a sensing range, as well as to enable compatibility with an optical communication system a cable system that uses a cable for optical fiber communication and optical fiber sensing of an environment surrounding the cable, wherein: the optical fiber communication is bidirectional communication using optical fiber pairs which are pairs of the optical fiber; in an optical fiber, a first wavelength band and a second wavelength band are different from each other; an optical amplification unit included in the optical amplification repeater device includes a first amplifier and a second amplifier that amplify rays of light in mutually opposing directions; and each of the communication optical signal, the probe light, and the backscattering light is amplified by at least either the first amplifier or the second amplifier.

Apparatus, systems, and techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables over multiple spans, as well as providing span-specific DAS information, are provided.

A system for simultaneously detecting audio-characteristics within a body over multiple body surface locations comprising a coherent light source directing at least one coherent light beam toward the body surface locations, an imager acquiring a plurality of defocused images, each is of reflections of the coherent light beam from the body surface locations. Each image includes at least one speckle pattern, each corresponding to a respective coherent light beam and further associated with a time-tag. A processor, coupled with the imager, determines in-image displacements over time of each of a plurality of regional speckle patterns according to said acquired images. Each one of the regional speckle patterns is at least a portion of a respective speckle pattern. Each regional speckle pattern is associated with a respective different body surface location. The processor determines the audio-characteristics according to the in-image displacements over time of the regional speckle patterns.

A system for simultaneously detecting audio-characteristics within a body over multiple body surface locations comprising a coherent light source directing at least one coherent light beam toward the body surface locations, an imager acquiring a plurality of defocused images, each is of reflections of the coherent light beam from the body surface locations. Each image includes at least one speckle pattern, each corresponding to a respective coherent light beam and further associated with a time-tag. A processor, coupled with the imager, determines in-image displacements over time of each of a plurality of regional speckle patterns according to said acquired images. Each one of the regional speckle patterns is at least a portion of a respective speckle pattern. Each regional speckle pattern is associated with a respective different body surface location. The processor determines the audio-characteristics according to the in-image displacements over time of the regional speckle patterns.

A contact vibration detection device 100 for detecting contact vibration due to contact between a rotational shaft 12 and a stationary part 13 includes: a rotation waveform determination unit 101 configured to determine a rotation waveform of the rotational shaft 12 based on displacement of the rotational shaft 12 during rotation; a parameter change detection unit 102 configured to detect a change in a parameter of at least one of an effective value of the rotation waveform or a phase angle of the rotation waveform; and a contact vibration determination unit 103 configured to determine whether the contact vibration occurs based on presence or absence of the change in the parameter.