Patent ID: 9320464
Filing Date: 2016-04-26
CPC Classification: A61B,G06K

Claim Text:
1. A method for measuring the oxygen saturation of the blood flowing in a peripheral human or animal body part, in which electromagnetic radiation (q 1 ′( t ), q 2 ′( t )) having a first wavelength and a second wavelength is irradiated into the peripheral body part or irradiated through the peripheral body part, reflected or transmitted radiation (x 1 ′( t ), x 2 ′( t )) corresponding to the first wavelength and the second wavelength is measured to form two measurement signals (x 1 ( t ), x 2 ( t )), and the oxygen saturation of the blood is determined by evaluating the two measurement signals, comprising: evaluating the two measurement signals with a mathematical mixing model, in which a useful-signal-related filter function related to the first wavelength, an interference-signal-related filter function related to the first wavelength, a useful-signal-related filter function related to the second wavelength, an interference-signal-related filter function related to the second wavelength, a useful source signal contained in the measurement signals and an interference source signal contained in the measurement signals are used in the evaluation, applying a statistical evaluation method to the two measurement signals, wherein, as a boundary condition, the statistical independence of the useful source signal and the interference source signal is assumed and determining therefrom the useful source signal and the two useful-signal-related filter functions, and determining the oxygen saturation of the blood using the three signals determined with the statistical evaluation, wherein the mathematical mixing model is a convolutive mixing model where the two measurement signals emerge from a superposition of filtered source signals which are filtered by mixing filters, wherein the following mathematical mixing model is used in evaluating the two measurement signals: wherein h