This invention is an article of clothing or clothing accessory for measuring body motion, posture, and/or configuration comprising sets of multiple flexible electromagnetic, light, and/or sound energy pathways, wherein each set longitudinally spans the same body joint in a selected configuration to increase measurement accuracy. Multiple flexible energy pathways longitudinally spanning the same body joint can transmit the same type or different types of energy (e.g. electromagnetic, light, or sound) and can transmit energy flows with the same flow parameters or different flow parameters.

Motion recognition clothing [TM] with flexible electromagnetic, light, or sonic energy pathways

Methods and apparatus for the active control of a wavelength-swept light source used to interrogate optical elements having characteristic wavelengths distributed across a wavelength range are provided.

Wavelength sweep control

A method of distributed acoustic sensing (DAS) whereby the derivative or rate of change of a signal backscatted from a fibre is measured. The change, or derivative of the phase measured in this way has a much smaller amplitude than the signal itself if the difference between the two times at which the signal is measured is much less than the period of the signal being measured, resulting in lower sensitivity. Frequency shifts can be applied to temporally displaced return signals to compare the rate of change, for example by employing an output interferometer arranged to modulate the signal in each arm by a different frequency shift.

Phase based sensing

This invention is smart clothing (such as a shirt or pair of pants) for ambulatory motion capture comprising: an article of clothing; an electromagnetic energy emitter; an electromagnetic energy receiver; a helical stretching and/or bending electromagnetic energy pathway that spans a body joint, wherein motion of the body joint stretches and/or bends the pathway, and wherein stretching and/or bending of the pathway changes the flow of electromagnetic energy from the emitter to the receiver; and a data processor, wherein the data processor analyzes changes in the flow in order to measure motion of the body joint.

Smart Clothing for Ambulatory Human Motion Capture

A method for monitoring for seismic events by interrogating an optic fibre which forms part of an existing communications infrastructure to provide distributed acoustic sensing (DAS). The signals provided by the distributed sensing provide measurements at each of a plurality of discrete portions along the fibre, which may be many tens of kilometres in length. Warning or measurement and consequently prediction of seismic activity can be provided by collecting data over a wide area, without the need to deploy a correspondingly large fibre network.

Wide Area Seismic Detection

An interrogator for a plurality of sensor fiber optic gratings. The interrogator includes a broadband optical source; at least one beam splitter directing output of the optical source to the sensor fiber optic gratings; at least one linear filter for converting changes in peak reflection wavelength to changes in intensity; at least one optical receiver; and at least one amplifier associated with each optical receiver. The interrogator also includes, alternatively, a driver/modulator for the optical source providing on/off pulses; an analog integrator following the at least one amplifier; or a mechanism compensating for masking of one sensor fiber optic grating by another.

Interrogator for a plurality of sensor fiber optic gratings

A fiber optic transducer is provided. The fiber optic transducer includes a fixed portion configured to be secured to a body of interest, a moveable portion having a range of motion with respect to the fixed portion, a spring positioned between the fixed portion and the moveable portion, and a length of fiber wound between the fixed portion and the moveable portion. The length of fiber spans the spring. The fiber optic transducer also includes a mass engaged with the moveable portion. In one disclosed aspect of the transducer, the mass envelopes the moveable portion.

Fiber optic transducers, fiber optic accelerometers and fiber optic sensing systems

A sensor apparatus combines an optical sensor in which acceleration, acoustic velocity, or displacement (vibration) causes a corresponding shift in the center wavelength of the sensor output, coupled to a high speed interferometric interrogator, through an unbalanced fiber interferometer. The unbalanced interferometer functions to translate optical wavelength shift into phase shift, which is easily demodulated by the interrogator.

Fiber optic particle motion sensor system

An optical detection system for monitoring a pipeline. The optical detection system includes a host node in the vicinity of, or remote from, a pipeline to be monitored. The optical detection system includes (a) an optical source for generating optical signals, and (b) an optical receiver. The optical detection system also includes a plurality of fiber optic sensors local to the pipeline for converting at least one of vibrational and acoustical energy to optical intensity information, each of the fiber optic sensors having: (1) at least one length of optical fiber configured to sense at least one of vibrational and acoustical energy; (2) a reflector at an end of the at least one length of optical fiber; and (3) a field node for receiving optical signals from the host node, the field node transmitting optical signals along the at least one length of optical fiber, receiving optical signals back from the at least one length of optical fiber, and transmitting optical signals to the optical receiver of the host node.

Fiber optic pipeline monitoring systems and methods of using the same

A fiber optic interrogator includes a broadband optical source, at least one beam splitter directing output of the optical source to an array of fiber optic gratings, at least one linear transmission or reflection filter, at least one optical receiver and at least one amplifier associated with each receiver. In one aspect of the invention, a linear transmission filter is used to convert the change in center wavelength of a grating reflectivity spectrum to a change in intensity, which is proportional to the change in the grating central wavelength. In another aspect of the invention, a pair of opposite-sloped linear transmission filters are utilized to normalize the received and filtered reflections with respect to total optical power. In another aspect of the invention, the optical source is pulsed, and return pulses from each fiber optic grating to be measured are sampled by the interrogator at different times. In another aspect of the invention, the source driver randomizes ripple phase versus wavelength to reduce wavelength measurement error. In another aspect of the invention, active closed-loop circuits are added to the receiver amplifiers to stabilize the amplifier output. In yet another aspect of the invention, a temperature-controlled compensating array of fiber optic gratings is interrogated each time the measurement array of gratings is interrogated. In still another aspect of the invention, a fast reset analog integrator is added to the amplifier stage(s) to improve the signal detection threshold. In another aspect of the invention, the wavelength measurement is compensated for the effects of one grating shading another.

Gerald Robert Baker

Papers

Interrogator for a plurality of sensor fiber optic gratings

Fiber optic transducers, fiber optic accelerometers and fiber optic sensing systems

Fiber optic particle motion sensor system

Fiber optic pipeline monitoring systems and methods of using the same

Wavelength measurement system