Techniques for accurately deriving physiologic parameters of a subject from photoplethysmographic measurements
US8298154B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2008 |
| Grant date | Oct 30, 2012 |
| Priority date | — |
| Expiry date | Sep 1, 2031 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/1455
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Several techniques are disclosed for isolating either heart or breath rate data from a photoplethysmograph, which is a time domain signal such as from a pulse oximeter. The techniques involve the use of filtering in the frequency domain, after a Fast Fourier Transform (FFT) has been conducted on a given photoplethysmograph also references as a given set of discrete time-domain data. The filtering may be applied to an identified fundamental frequency and one or more harmonics for heart related parameters. The filter may be truncated to the frequency data set and further applied multiple times to improve roll off. After filtering, an Inverse FFT (IFFT) is used to reconstruct the time-domain signal, except with undesirable frequency content eliminated or reduced. Calculation or measurement of parameters is then conducted on this reconstructed time-domain signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.