Title
Contactless multiple wavelength photoplethysmographic imaging: A first step toward "spO2 camera" technology
Author
Wieringa, F.P.
Mastik, F.
van der Steen, A.F.W.
TNO Kwaliteit van Leven
Publication year
2005
Abstract
We describe a route toward contactless imaging of arterial oxygen saturation (SpO2) distribution within tissue, based upon detection of a two-dimensional matrix of spatially resolved optical plethysmographic signals at different wavelengths. As a first step toward SpO 2-imaging we built a monochrome CMOS-camera with apochromatic lens and 3λ-LED-ringlight (λ1 = 660 nm, λ 2 = 810 nm, λ3 = 940 nm; 100 LEDs λ -1). We acquired movies at three wavelengths while simultaneously recording ECG and respiration for seven volunteers. We repeated this experiment for one volunteer at increased frame rate, additionally recording the pulse wave of a pulse oximeter. Movies were processed by dividing each image frame into discrete Regions of Interest (ROIs), averaging 10 × 10 raw pixels each. For each ROI, pulsatile variation over time was assigned to a matrix of ROI-pixel time traces with individual Fourier spectra. Photoplethysmograms correlated well with respiration reference traces at three wavelengths. Increased frame rates revealed weaker pulsations (main frequency components 0. 95 and 1.9 Hz) superimposed upon respiration-correlated photoplethysmograms, which were heartbeat-related at three wavelengths. We acquired spatially resolved heartbeat-related photoplethysmograms at multiple wavelengths using a remote camera. This feasibility study shows potential for non-contact 2-D imaging reflection-mode pulse oximetry. Clinical devices, however, require further development.
Subject
Biomedical Innovation
Biology
Healthy Living
Multispectral imaging
Pulse oximetry
Cardiology
Electrocardiography
Light emitting diodes
Oximeters
Saturation (materials composition)
Signal processing
Photoplethysmographic imaging
Medical imaging
Computer assisted diagnosis
Transcutaneous oxygen monitoring
Monitoring, Physiologic
Photoplethysmography
To reference this document use:
http://resolver.tudelft.nl/uuid:94e3cb15-75b9-4e54-9ec0-825523e3eaed
TNO identifier
238775
ISSN
0090-6964
Source
Annals of Biomedical Engineering, 33 (8), 1034-1041
Document type
article