To expand a measurement range with regard to SDH-BOTDR.

A BFS1 and a BFS2, which is obtained by inverting the BFS1, are acquired on the basis of a first measurement signal and a first local oscillation signal that is a cosine wave, a BFS3 is acquired on the basis of a second measurement signal and a second local oscillation signal that is a sine wave, and a Brillouin frequency shift waveform is synthesized from the BFS1 to BFS3. In the case where an optical fiber is not strained or in the case where temperature of the optical fiber is not changed, a phase rotation number N, which is a phase difference between a measurement signal and a local oscillation signal, is calculated on the basis of intensity of the measurement signal, and an offset corresponding to the phase rotation number N is given to the synthesized Brillouin frequency shift waveform.

A prism coupling system configured to determine at least one stress characteristic in a chemically strengthened substrate having a surface and a near-surface waveguide has a a light source system that generates measurement light. A coupling prism provides optical coupling of the measurement light into and out of the near-surface waveguide over an optical path that comprises a low-angle region and a high-angle region. A detector system arranged to receive the measurement light from the coupling prism to detect a mode spectrum image. A light-blocking member is operably disposed to at least partially extend into the low-angle region without extending into the high-angle region to increase or optimize the contrast of the mode spectrum image.

A prism coupling system configured to determine at least one stress characteristic in a chemically strengthened substrate having a surface and a near-surface waveguide has a a light source system that generates measurement light. A coupling prism provides optical coupling of the measurement light into and out of the near-surface waveguide over an optical path that comprises a low-angle region and a high-angle region. A detector system arranged to receive the measurement light from the coupling prism to detect a mode spectrum image. A light-blocking member is operably disposed to at least partially extend into the low-angle region without extending into the high-angle region to increase or optimize the contrast of the mode spectrum image.

A method for predicting a clamp force using a convolutional neural network includes: generating a cepstrum image from a signal processing analysis apparatus; extracting a characteristic image by multiplying a predetermined weight value to pixels of the generated cepstrum image through artificial intelligence learning; extracting, as a representative image, the largest pixel from the extracted characteristic image; synthesizing an image by synthesizing the extracted representative image information; and predicting a clamp force by comparing the synthesized image with a predetermined value.

A method for predicting a clamp force using a convolutional neural network includes: generating a cepstrum image from a signal processing analysis apparatus; extracting a characteristic image by multiplying a predetermined weight value to pixels of the generated cepstrum image through artificial intelligence learning; extracting, as a representative image, the largest pixel from the extracted characteristic image; synthesizing an image by synthesizing the extracted representative image information; and predicting a clamp force by comparing the synthesized image with a predetermined value.

An optical sensor according to an embodiment of the present disclosure includes a light emitting substrate and a circuit board. The light emitting substrate includes a light emitting device. The circuit board is provided at a position opposing the light emitting device. The circuit board includes a light transmitting section and one or multiple light receiving devices. The light transmitting section transmits light of the light emitting device. The one or multiple light receiving devices receive light reflected by a reflective layer of the light of the light emitting device exiting through the light transmitting section. For example, the one or multiple light receiving devices are formed on a first major surface of the circuit board. For example, the light emitting substrate is disposed at a position opposing a second major surface, of the circuit board, on an opposite side to the first major surface, and is stacked on the circuit board with a first bump interposed therebetween.

A soft, flexible microtube sensor and associated method of sensing force are described. A liquid metallic alloy is sealed within a microtube as thin as a strand of human hair to form the physical force sensing mechanism. The sensor is hardly distinguishable with the naked eye, and can be used for the continuous biomonitoring of physiological signals, such as unobtrusive pulse monitoring. Also described is a method of fabricating the microtube sensor and wearable devices incorporating one or more microtube sensors.

A method of mounting a rail monitoring member/element at a mounting location of a rail for rail traffic, in particular on a railway track, is disclosed. The rail monitoring member includes a strain sensor member with a carrier on which a strain gauge, being an optical fiber with a fiber Bragg grating, is fixed. The method steps include: determination of the temperature of the rail and/or rail monitoring member at the mounting location; checking whether the determined temperature is within a predefined temperature interval; providing heating or cooling application to the rail and/or rail monitoring member at the mounting location, if the determined temperature is not within the predefined temperature interval; positioning and adhesively fixing of the carrier of the rail monitoring member at the mounting location. The method can be carried out easily and allows reliable and accurate monitoring of the rail using a strain sensor member.

An ultrasound system is disclosed that includes an ultrasound imaging device including a display screen, a processor and memory having stored thereon logic, and an ultrasound probe. The logic of the ultrasound imaging device, upon execution by the processor, can causes an alteration of content displayed on the display screen in accordance of with ultrasound probe movement-related data. The ultrasound imaging device can include a light source configured to provide incident light to the optical fiber cable, the optical fiber cable including a plurality of reflective gratings disposed along a length thereof. Each of the plurality of reflective gratings can be configured to reflect light with different specific spectral widths to provide distributed measurements in accordance with strain applied to the optical fiber cable. The ultrasound imaging device can obtain the ultrasound probe movement-related data through an optical fiber.

A method and system for stress engineering of a transparent material can include an imaging system that can visualize a spatial distribution of an internal stress in a transparent material, an actuator system that can induce stress in the transparent material, the actuator system comprising one or more actuator elements, and a feedback system that can communicate with the imaging system and the actuator system, and which can guide an internal stress distribution in the transparent material toward a preferred final state.