Determination of Oxygen Saturation and Photoplethysmogram from Near Infrared Scattering Images

TL;DR

This paper presents a novel method to determine oxygen saturation and photoplethysmogram from near-infrared scattering images of muscle, enabling non-invasive assessment of blood oxygen levels and heart rate in heterogeneous tissues.

Contribution

It introduces a new approach combining modified Beer-Lambert Law and diffuse scattering models to extract physiological parameters from NIR images, addressing local tissue heterogeneity.

Findings

Successfully determined oxygen saturation distribution in muscle.

Extracted photoplethysmogram and heart rate from scattering images.

Applicable to local regions of heterogeneous muscle and skin.

Abstract

The near infrared scattering images of human muscle include some information on bloodstream and hemoglobin concentration according to skin depth and time. This paper addressed a method of determining oxygen saturation and photoplethysmogram from the near infrared (NIR) scattering images of muscle. Depending on the modified Beer-Lambert Law and the diffuse scattering model of muscular tissue, we determined an extinction coefficient matrix of hemoglobin from the near infrared scattering images and analyzed distribution of oxygen saturation of muscle with a depth from the extinction coefficient matrix. And we determined a dynamic attenuation variation curve with respect to fragmentary image frames sensitive to bloodstream from scattering image frames of muscle with time and then obtained the photoplethysmogram and heart rate by Fourier transformation and inverse transformation. This method based on the NIR scattering images can be applied in measurement of an average oxygen saturation and photoplethysmogram even in local region of optically heterogeneous muscle and skin.