Abstract
This paper proposes a gating algorithm that employs the successively compensated norm ratio SΦN+g to separate a submerged pulse wave from a body movement artifact without the need to designate an artifact pulse segment that is measured over two wavelengths (denoted by IR, R) of SpO2. This algorithm uses predetermined rules to classify IR,R signals into a pulse wave and an artifact. One disadvantage of using an inverse matrix to separate the pulse signal is that it can generate spikes and oscillations at the ill-condition for the separation matrix. It is thus important to apply a relaxation algorithm at the ill-condition. The proposed gating algorithm opens and closes the gate to automatically separate the pulse segment and the artifact segment according to pre-determined rules. It therefore enables more flexible ΦNtrue tracking. The proposed gated successively compensated norm ratio SΦN+g results in improved separation of the pulse wave (H = 0.0382) without the need for precise ΦN adjustment than the separation obtained using ΦN (H = 0.2781). This algorithm is also effective when there are other body movement artifacts present. This algorithm can not only be applied to two-wave pulse photometry, but it can be also be extended to multi-wave pulse photometry.
