Near infrared rays of .lambda.1, .lambda.2, .lambda.3 in wavelength which are different from and near to one another are irradiated from a light source (2) to a part being measured (F) of a living body in such a state that vein bloodstream at the part being measured is stopped by applying a press force of a cuff (8), and the intensities of the transmitted near infrared rays of .lambda., .lambda.2, .lambda.3 in wavelength are detected by a photodetector (4) at the same time. In a processing circuit (14), the absorbance secondary differential value of the near infrared rays by the part being measured (F) is calculated on the basis of the transmitted light intensity detection values thus detected at the same time with respect to the three wavelengths, the variation width thereof within a predetermined time is calculated and then the blood sugar value in the living body is determined from the absorbance secondary differential value variation width on the basis of a calibration curve.
A personal identification system, which uses a vein pattern of a finger, optimizes the amount of light of a light source based on a captured finger image and emphasizes the vein pattern during image processing for identification.
A method for predicting blood glucose level of a person includes performing on the person a near-infrared spectral scan of a body part at a first group of wavelengths and at a second group of wavelengths, determining a first group of near-infrared absorbance values for the first group of wavelengths and a second group of near-infrared absorbance values for the second group of wavelengths, determining a first difference for the first group of near-infrared absorbance values and a second difference for the second group of near-infrared absorbance values, and calculating a blood glucose level for the person using the first and second differences.
A method and device are presented for use in non-invasive optical measurements of at least one desired characteristic of patient's blood. A condition of artificial blood kinetics is created at a measurement location in a patient's blood perfused fleshy medium and maintained for a certain time period. This condition is altered over a predetermined time interval within said certain time period so as to modulate scattering properties of blood. Optical measurements are applied to the measurement location by illuminating it with incident light beams of at least two different wavelengths in a range where the scattering properties of blood are sensitive to light radiation, detecting light responses of the medium, and generating measured data indicative of time evolutions of the light responses of the medium for said at least two different wavelengths, respectively, over at least a part of said predetermined time interval.
The method and device serve to measure a proportion of constituents in blood. To this end, electromagnetic radiation of different radiation wavelengths is directed through a tissue (9) containing blood vessels (1). At least a portion of the radiation exiting the vessel is detected using sensors, and a corresponding measured value derived therefrom is fed to an evaluating device. The evaluating device (10) is connected to at least two sensors (2, 3, 4) and has an analyzer (11) for determining a dispersion of radiation by evaluating the intensity of the radiation received by the individual sensors. An individual calibration determination is carried out by evaluating the angle-dependent dispersion and can be drawn upon for conducting a pulse spectroscopic determination of concentrations of substances.
