It is proposed a method for monitoring an electrical power supply line comprised in a seismic cable and extending along the seismic cable. The seismic cable includes: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, and an optical transmission line extending along the seismic cable for carrying data signals from or towards the controllers. The electrical power supply line supplies at least one pair of master and slave controllers. The master controller of a given pair of master and slave controllers performs a step of monitoring a portion of the electrical power supply line between the master and slave controllers, by using an optical loop established on a portion of the optical transmission line between the master and slave controllers, and starting from the master controller and passing through the slave controller.

A method for configuring a sensor of a non-interference stress management system is disclosed. The method may include determining a focal distance between a light transmitting fiber and a transmit lens, the focal distance configured to focus light from the transmit fiber to form a focused transmit beam, the transmit beam targeting a reflective structure. The method may further include positioning the light transmitting fiber and the transmit lens, wherein the light transmitting fiber and the transmit lens are separated by a transmit gap based on the focal distance and positioning a light receptive fiber and a receive lens to receive a focused reflected beam from the reflective structure, wherein the light receptive fiber is separated from the receive lens by a receive gap based on the focal distance.

A method for measuring the positions of centers of curvature of optical surfaces of a single- or multi-lens optical system, an imaging lens system simultaneously images an object plane into a first and a second image plane. The optical system is arranged so that a supposed position of a first center of curvature is situated in the first image plane of the imaging lens system and a supposed position of a second center of curvature is situated in the second image plane of the imaging lens system. An object arranged in the object plane is then imaged simultaneously or sequentially at the first and the second image plane by means of measuring light. Reflections of the measuring light at optical surfaces of the optical system are detected by means of a spatially resolving light sensor. The actual positions of the first and the second center of curvature are calculated from the detected reflexes.

A method for measuring the positions of centers of curvature of optical surfaces of a single- or multi-lens optical system, an imaging lens system simultaneously images an object plane into a first and a second image plane. The optical system is arranged so that a supposed position of a first center of curvature is situated in the first image plane of the imaging lens system and a supposed position of a second center of curvature is situated in the second image plane of the imaging lens system. An object arranged in the object plane is then imaged simultaneously or sequentially at the first and the second image plane by means of measuring light. Reflections of the measuring light at optical surfaces of the optical system are detected by means of a spatially resolving light sensor. The actual positions of the first and the second center of curvature are calculated from the detected reflexes.

A monitoring system includes an axle weight measurer and a state estimator. The axle weight measurer detects a surface displacement of a road from a first captured image obtained by imaging the road when a vehicle passes at a predetermined spot of a structure having the road that the vehicle passes, and calculates an axle weight of the vehicle from the surface displacement and a displacement coefficient of the road. The state estimator generates an axle weight distribution from the axle weight calculated by the axle weight measurer, and estimates a deterioration degree of the structure, using the axle weight distribution.

Systems, methods and device provided for combining or splitting laser beams, including a plurality of optical fibers for providing laser beams, an image relay lens for each of the plurality of optical fibers, positioning a prism beam combiner or splitter after the image relay lenses for combining or splitting the laser beams. According to another aspect, the a prism beam combiner or splitter may include a flattened tip to transmit a portion of an input laser beam, a position sensitive detector to receive the transmitted portion of the input laser beam to track a beam axis motion and provide feedback alignment error signals based on the beam axis motion, and a driver to receive the feedback alignment error signals and to drive a motor or piezo actuated beam steering minor based on the feedback alignment error signals, wherein a laser bond inspection method implements the described systems and methods.

Techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables are provided. For example, DAS range can be extended by transmitting and amplifying a DAS signal along multiple spans of a first optical fiber, routing or bypassing the DAS signal from the first optical fiber to a second optical fiber different from the first fiber via a high-loss loopback architecture, and returning and amplifying the DAS signal along the same multiple spans back to a DAS device. The DAS device may then receive and process the DAS signal to detect any changes in the DAS environment. The loopback configuration may be based on different types of loopback architecture.

A wind tunnel for a motor vehicle, with a fan, a test section, through which an air stream generated by the fan can flow, a recording device for recording different motor vehicles within the test section, and a testing device for determining aerodynamic characteristics of the motor vehicle. The wind tunnel also includes an optical sensing device for sensing an outer contour of the motor vehicle recorded by the recording device, an evaluating unit and a linking unit. The evaluating unit determines a vehicle configuration from the outer contour of the motor vehicle sensed by the optical sensing device. The linking unit links the vehicle configuration of the motor vehicle determined by the evaluating unit with the test results determined by the testing device.

A stress distribution image processing device including: a processing unit configured to: designate a normalization region which includes a portion of stress equal to or larger than a predetermined threshold value in a screen of a stress distribution image of a target object; and normalize pixels in the normalization region based on stress values in the normalization region to obtain a normalized image.

A system (100) for the identification of the formation of a burning droplet (9) of a material of a fiber optic cable (3) during cable burn testing comprises a data processing device (11) for processing respective image data of a plurality of image samples of an image stream. The data processing device (11) is configured to execute at least a processing step of preprocessing each of the recorded image samples of the image stream to generate a respective preprocessed image sample for each of the recorded image samples such that areas of the recorded image samples disturbing the identification of burning droplets (9) are masked out in the respective preprocessed image sample, and a step of identifying a burning droplet (9) in each of the preprocessed image samples by evaluating a pixel color property of a pixel of each preprocessed image sample.