Design of a device for skin tone characterization in PPG applications

Student thesis: Master's Thesis


Monitoring physiological parameters in a constant and reliable supervision is essential
for medicine and patient care. There are invasive and not invasive devices in order to
do so, and Photoplethysmography (PPG) is one of the most popular methods because
of its non-invasiveness, simplicity and low-cost, mostly known by its application on
pulse oximeters for extracting the oxygen saturation of the blood. PPG can be used
to obtain more physiological parameters and characterization of the different layers
and types of skin, however, the current measurements provided by PPG are quite
inaccurate due to characteristics that directly affect the quality of PPG signal such
as skin color. There are already on the market good and reliable devices for measuring
the amount of melanin in the skin that will directly influence the color (specifically
the Mexameter ® MX 18 used as a ”gold standard” in the presented work). This
thesis presents a new device used to measure skin tone in PPG applications. The
existing technology is evaluated in first place which leads to the development of our
in-house solution. Finally, an analysis and comparison between measurements is
carried out to prove the efficiency of our solution versus the already mentioned gold
standard, opening opportunities for further works on avoiding artifacts at PPG signal
Date of Award2 Feb 2022
Original languageEnglish
SupervisorJohan Stiens (Promotor), Angel Sole Morillo (Advisor) & Joan Lambert Cause (Advisor)


  • Artifacts
  • Mexameter
  • Photoplethysmography
  • Skin Color

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