HIGH RESOLUTION HADAMARD TRANSFORM OXIMETRY

摘要

The principle of pulse oximetry is based on the different absorption of haemoglobin at various wavelengths in the visible and IR-region, utilizing Lambert-Beers law. With conventional oximeters a part of the human body is penetrated by radiation at two wavelengths and the oxygen saturation is calculated from the detected signals. Intention of the optical set-up presented here is the improvement of the signal-to-noise-ratio of the detected signals by a modified signal generation. Radiation of three different sources penetrates the human skin in a time-multiplex sequence, which is designated by a Hadamard matrix. The signals of the distinct radiation sources are obtained mathematically from the detected sum signals. The optical set-up exemplifies the principle, which can be transferred to other blood ingredients than haemoglobin when the emitting wavelengths of the radiation sources are changed.