Annals of Biomedical Engineering

, Volume 33, Issue 8, pp 1034–1041 | Cite as

Contactless Multiple Wavelength Photoplethysmographic Imaging: A First Step Toward “SpO2 Camera” Technology

  • F. P. Wieringa
  • F. Mastik
  • A. F. W. van der Steen


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 SpO2-imaging we built a monochrome CMOS-camera with apochromatic lens and 3λ-LED-ringlight (λ1 = 660 nm, λ2 = 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.


Pulse oximetry Multispectral imaging Contactless measurement of respiration and heart action 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Aoyagi, T., M. Kishi, K. Yamaguchi, and S. Watanabe. Improvement of an earpiece oximeter. Presented at 13th annual meeting of the Japanese Society for Medical Electronics and Biological engineering, Osaka, 1974.Google Scholar
  2. 2.
    Aoyagi, T., N. Kobayashi, and T. Sasaki. Apparatus for determining the concentration of a light-absorbing material in blood. US Patent No. US4832484 1989.Google Scholar
  3. 3.
    Boas, D. A., M. A. Franceschini, A. K. Dunn, and G. Strangman. Noninvasive imaging of cerebral activation with diffuse optical tomography. In: In Vivo Optical Imaging of Brain Function, edited by R. D. Frostig. Boca Raton: CRC Press, 2002, pp. 193–221Google Scholar
  4. 4.
    Dassel, C. Experimental Studies on Reflectance Pulse Oximetry: Specific Aspects of Intrapartum Fetal Monitoring. Doctoral thesis. RUG, Groningen, 1997, p. 157.Google Scholar
  5. 5.
    Eberhart, R. C., and A. Shitzer. Volume 1, Chapter 1: Introduction. In: Heat transfer in medicine and biology: Analysis and applications, edited by A. Shitzer, and R. C. Eberhart. London: Plenum Press, 1985, pp. 2–4.Google Scholar
  6. 6.
    Franceschini, M. A., D. A. Boas, A. Zourabian, S. G. Diamond, S. Nadgir, D. W. Lin, J. B. Moore, and S. Fantini. Near-infrared spiroximetry: Noninvasive measurements of venous saturation in piglets and human subjects. J. Appl. Physiol. 92:372–384, 2002.PubMedGoogle Scholar
  7. 7.
    Franceschini, M. A., E. Gratton, and S. Fantini. Noninvasive optical method of measuring tissue and arterial saturation: An application to absolute pulse oximetry of the brain. Opt. Lett. 24:829–831, 1999.Google Scholar
  8. 8.
    Gilbert, D. L. The first documented report of mountain sickness: The China or Headache Mountain story. Respir. Physiol. 52:315–326, 1983.CrossRefPubMedGoogle Scholar
  9. 9.
    Graaff, R. Tissue Optics Applied to Reflectance Pulse Oximetry. Doctoral thesis. RUG, Groningen. 1993, pp. 235.Google Scholar
  10. 10.
    ISO/TC121/SC3. ISO/DIS 9919 Medical electrical equipment–-Particular requirements for the basic safety and essential performance of pulse oximeters for medical use. ISO, 2003.Google Scholar
  11. 11.
    ISO/TC121/SC3-IECSC62D/JWG4. IEC/CD 60601-2-54 Medical electrical equipment–-Part 2-54: Particular requirements for the basic safety and essential performance of pulse oximeters for medical use. ISO/IEC, 2002.Google Scholar
  12. 12.
    Martine, G. Essays and Observations on the Construction and Gradation of Thermometers, and on the Heating and Cooling of Bodies. Edinburgh. 1740.Google Scholar
  13. 13.
    New, W., and J. E. Corenman. Pulse Oximeter. Patent No. US414176 1982.Google Scholar
  14. 14.
    Palreddy, S. Signal Processing Algorithms. In: Design of pulsoximeters, edited by J. G. Webster. Bristol: Institute of Physics Publishing, Dirac House, Temple Back, Bristol BS1 6BE, UK, 1997, pp. 124–158.Google Scholar
  15. 15.
    Severinghaus, J. W., P. Astrup, and J. F. Murray. Blood gas analysis and critical care medicine. Am J. Respir. Crit. Care Med. 157:S114–S122, 1998.PubMedGoogle Scholar
  16. 16.
    Severinghaus, J. W., and Y. Honda. History of blood gas analysis. VII. Pulse oximetry. J. Clin. Monit. 1987.Google Scholar
  17. 17.
    Siegel, A., J. J. A. Marota, and D. A. Boas. Design and evaluation of a continuous-wave diffuse optical tomography system. Opt. Express 4:278–298, 1999.Google Scholar
  18. 18.
    Smith, P. R., and M. J. Hayes. Artefact Reduction in Photoplethysmography. PCT Patent No. WO 99/32030 1999.Google Scholar
  19. 19.
    Wieringa, F. P. Imaging Apparatus for Displaying Concentration Ratios. WO Patent No. WO 01/15597 A1 2001.Google Scholar
  20. 20.
    Woods, D. D., E. S. Patterson, and E. M. Roth. Can we ever escape from data overload? A cognitive systems diagnosis. Cogn. Technol. & Work. 22–36, 2002.Google Scholar
  21. 21.
    Wunderlich, C. R. A. Das Verhalten der Eigenwärme in Krankheiten. Leipzig: Wigand, 1868.Google Scholar
  22. 22.
    Yoshiya, I., Y. Shimada, and K. Tanaka. Spectrophotometric monitoring of arterial oxygen saturation in the fingertip. Med. Biol. Eng. Comput. 18:27–32, 1980.PubMedGoogle Scholar

Copyright information

© Biomedical Engineering Society 2005

Authors and Affiliations

  • F. P. Wieringa
    • 1
    • 2
  • F. Mastik
    • 1
  • A. F. W. van der Steen
    • 1
    • 3
  1. 1.Erasmus Medical Center, Biomedical EngineeringRotterdamThe Netherlands
  2. 2.TNO Prevention and HealthLeidenThe Netherlands
  3. 3.Interuniversity Cardiology Institute of the Netherlands (ICIN)The Netherlands

Personalised recommendations