Abstract: An intracranial pressure estimating method includes: an acquisition step (S10) of acquiring time-series data on external ear canal pressure pulse waves of a subject; an analysis step (S12) of analyzing external ear canal pressure pulse wave data obtained by digitalizing the time-series data on the external ear canal pressure pulse waves, to calculate a first formant frequency of the external ear canal pressure pulse wave data; a correction step (S13) of correcting the calculated first formant frequency based on personal information on the subject to calculate a corrected value; and an estimation step (S14) of calculating an estimated value of an intracranial pressure based on the calculated corrected value.

Abstract: An intracranial pressure estimating method includes: an acquisition step (S10) of acquiring time-series data on external ear canal pressure pulse waves of a subject; an analysis step (S12) of analyzing external ear canal pressure pulse wave data obtained by digitalizing the time-series data on the external ear canal pressure pulse waves, to calculate a first formant frequency of the external ear canal pressure pulse wave data; a correction step (S13) of correcting the calculated first formant frequency based on personal information on the subject to calculate a corrected value; and an estimation step (S14) of calculating an estimated value of an intracranial pressure based on the calculated corrected value.

Abstract: An electromagnetic flowmeter generates a magnetic filed perpendicular to a ring earth electrode contacting fluid at an end portion of a measuring tube and a point electrode attached to a lower portion of the measuring tube so as to measure a flow rate without depending on a fluid level. The electromagnetic flowmeter comprises magnetic field generation means for generating the magnetic field in the measuring tube to be perpendicular to an axial direction of the measuring tube such that electromotive force generated in fluid is not influenced by the fluid level, flow rate output means for calculating a flow rate of fluid flowing in the measuring tube based on a potential developed in the fluid by said magnetic filed generated by the magnetic field generation means so as to output the calculated flow rate, and display means for displaying the flow rate calculated by the flow rate calculation means.

Abstract: A temperature distribution measuring apparatus and related method uses optical time domain reflectometry to determine temperature distribution along an optical fiber. A light pulse enters the fiber at one end, and backscattered light at each of various points in the optical fiber has a Raman spectrum which contains temperature information. An impulse response to the Raman spectra of backscattered light is produced using a transformation to provide a temperature distribution along the optical fiber. An impulse response on the anti-Stokes component and an impulse response of the Stokes component of the Raman spectrum are each produced, and the ratio between them indicates temperature distribution. Each impulse response is obtained by performing deconvolution on the Stokes component and the anti-Stokes component using an inverse matrix of measured incident light, the inverse matrix being obtained by an iteration method with an optimum number of iterations.

Abstract: In a light-temperature distribution sensor, Raman scattering light is extracted from back scattering light produced by a light pulse supplied into an optical fiber, thereby calculating a temperature distribution. An intensity distribution signal of anti-Stokes Raman scattering light is extracted from the back scattering light. An intensity distribution signal of Stokes Raman scattering light is extracted from the back scattering light. An intensity distribution signal of Rayleigh scattering light is extracted from the back scattering light. The intensity distribution signal of the anti-Stokes Raman scattering light and the intensity distribution signal of the Stokes Raman scattering light are normalized, with the intensity distribution signal of the Rayleigh scattering light used as reference signal.

Abstract: In a temperature distribution measuring apparatus which projects pulsed-light into an optical fiber, measures Raman spectrum of backscattered light occurred in the optical fiber, and obtains a temperature distribution along the optical fiber, to improve the positional resolution, it is necessary to narrow the width of the incident pulsed-light. A response of the backscattered light to a pulsed-light of a finite width is considered to be convolution and deconvolution of the measured value of the backscattered light is performed to obtain an impulse response. Deconvolution which is an inverse transform requires a waveform of the incident light and which is previously measured. When deconvolution is performed by using an inverse matrix of the incident light, it is necessary to calculate the inverse matrix by means of an iteration method.

Abstract: An apparatus for measuring a temperature distribution along an optical fiber, comprises a light source for inputting pulsed-light into the optical fiber, an optical filter for receiving backward Raman-scattered light from the optical fiber and extracting anti-Stokes' light and Stokes' light, an optical attenuator for attenuating the intensity of the Stokes' light extracted by the optical filter, first and second signal paths each of which includes a light-receiving element and an analog-to-digital converter, a signal processor for calculating a temperature distribution along the optical fiber on the basis of the first and second signal paths, and an optical switch having a first input port for receiving the anti-Stokes' light, a second input port for receiving the Stokes' light, a first output port, and a second output port, the optical switch transmitting the anti-Stokes' light and the Stokes' light to the first output port and the second output port in a first switching position and transmitting the Stokes'

Abstract: A temperature distribution measuring apparatus, which inputs pulsed-light into an optical fiber, measures backward Raman-scattered light generated in the optical fiber, and calculates a temperature distribution along the optical fiber in accordance with the ratio of the intensity of anti-Stokes' light to the intensity of Stokes' light of the backward Raman-scattered light.

Abstract: An apparatus for measuring temperature along an optical fiber uses backscattered light and optical time domain reflectometry to obtain a measure of the temperature distribution along the fiber. The ratio of anti-Stokes Raman to Stokes Raman backscattered light is used to determine the temperature distribution. In order to compensate for fluctuations in the wavelength of a laser source there is provided in a first embodiment an optical filter which passes Fresnel components of the light reflected from a distal end of the fiber. Changes in the ratio of the filtered Fresnel components correspond to changes in the source wavelength which may then be compensated by adjusting the source wavelength. In a second embodiment, the optical filter is used to measure the ratio of anti-Stokes Raman and Stokes Raman backscattered components derived from a reference temperature section of the fiber in which the temperature is held constant.

Abstract: An apparatus for optical power transmission capable of reducing a number of photo cells and improving a power transmission efficiency, and an optically powered system using the apparatus capable of maximizing lifetime of light sources. The apparatus includes an alternating current transformer for transforming the electric power to a desired level for a load. The system further includes a device for detecting magnitude of the electric power, and a device for controlling an amount of light emission by the light source in accordance with the detected magnitude of the electric power such that the magnitude of the electric power to be given to the load is maintained to be substantially constant.

Abstract: According to the instant invention, two input light transmitting lines or paths are used which transmit the wavelength input light of the same wavelength. A detecting portion modulates the two inputs according to the physical quantity to be measured and produces separate outputs along two output transmitting paths. A processing portion processes the two outputs and calculates the physical quantity to be measured.In the detecting portion, each of the inputs is split into two separate light signals each of which varies at a different rate due to the effects of the physical quantity. The two separated light signals follow a respective output transmitting paths. As a result, two output signals are produced along the output paths for each input light applied to the detecting portion.