Using hybrid printed electronics technology, Holst Centre has developed a wearable optical sensor by integrating silicon photodiodes with multiple light sources and readout electronics into a lightweight and flexible patch. By recording optical signals from the skin using light sources with different wavelengths, our patch simultaneously measures signals from different skin depths. This provides advantages to overcome significant challenges in the field.

Our current R&D is focused on photoplethysmography (PPG) by recording optical signals from the illumination of the human tissue. Morphological features from the PPG signal can be translated into cardiovascular parameters of interest such as heart rate, heart rate variability, respiratory rate and oxygen saturation (SpO2). With wearable sensors there is a demand for application with increased activity, however this causes significant motion artifacts, resulting in a reduction of the signal quality, which has a major impact on clinical reliability and accuracy.  

Your challenge

Working in an interdisciplinary team of engineers and scientist (electrical engineering, material science, biomedical photonics) you will measure and analyse PPG signals using Holst Centre’s wearable optical sensor patch and existing software platforms. The focus will be to assess the signal quality of PPG with systematic assessment of determined motion artifacts. Following that, you will determine which improvements can be made within the wearable device design to reduce motion artifacts.

Project goal

• Gain a basic understanding of biomedical optics and of propagation of the light in the human tissue

• Provide a literature review on state-of-the-art developments to reduce motion artifacts in optical devices

• Develop methodologies to test motion artifacts and signal processing algorithms.

• Acquire PPG signals with Holst Centre’s wearable optical patch and compare devices within specific methodologies

• Set protocols to test functionality in specific motions

• Conduct experiments and potential volunteer study

• Communicate via presentations and report writing findings

Your tasks

As a team member your tasks will be:

• Knowledge acquisition through literature survey, discussion with other team members, and internal seminars/colloquiums

• Data acquisition through measurements

• Analysis and presentation of experimental data

• Documentation of results in a technical report or scientific publication

• Presentation of results in internal seminars

Your Profile

• A master’s degree in biomedical engineering, electrical engineering, physics, optics or related with both theoretical and experimental skills.

• Knowledge in signal processing, filtering, calibration, data analysis using MATLAB/Python or other platforms

• Experience in signal processing and algorithms development

• You have good communication skills in English

• Independent but also a team player

• Affinity for biomedical photonics

• Analytical skills – ability to make analysis of complex situation and make a plan forward

Have we sparked your interest? Then please send your application or any question you may have to:

Razvan Petre (adrian-razvan.petre@tno.nl)