Noncontact simultaneous dual wavelength photoplethysmography: A further step toward noncontact pulse oximetry
- Department of Electronic Engineering, National University of Ireland, Maynooth, Maynooth Co. Kildare (Ireland)
We present a camera-based device capable of capturing two photoplethysmographic (PPG) signals at two different wavelengths simultaneously, in a remote noncontact manner. The system comprises a complementary metal-oxide semiconductor camera and dual wavelength array of light emitting diodes (760 and 880 nm). By alternately illuminating a region of tissue with each wavelength of light, and detecting the backscattered photons with the camera at a rate of 16 frames/wavelength s, two multiplexed PPG wave forms are simultaneously captured. This process is the basis of pulse oximetry, and we describe how, with the inclusion of a calibration procedure, this system could be used as a noncontact pulse oximeter to measure arterial oxygen saturation (S{sub p}O{sub 2}) remotely. Results from an experiment on ten subjects, exhibiting normal S{sub p}O{sub 2} readings, that demonstrate the instrument's ability to capture signals from a range of subjects under realistic lighting and environmental conditions are presented. We compare the signals captured by the noncontact system to a conventional PPG signal captured concurrently from a finger, and show by means of a J. Bland and D. Altman [Lancet 327, 307 (1986); Statistician 32, 307 (1983)] test, the noncontact device to be comparable to a contact device as a monitor of heart rate. We highlight some considerations that should be made when using camera-based ''integrative'' sampling methods and demonstrate through simulation, the suitability of the captured PPG signals for application of existing pulse oximetry calibration procedures.
- OSTI ID:
- 20953433
- Journal Information:
- Review of Scientific Instruments, Vol. 78, Issue 4; Other Information: DOI: 10.1063/1.2724789; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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