Olivier Romain

Pulse oximetry using a buried quad junction photodetector

Traditional pulse oximeters rely on the use of red and infrared LEDs and a photodiode for measuring transmittance between tissues and estimate the functional oxygen saturation. Currently, studies are being made for the development of multiwavelength pulse oximeters in order to increase accuracy and to estimate the presence of other compounds such as carboxyhemoglobin or methemoglobin. The purpose of this work is the characterization and implementation of a pulse oximeter with a Buried Quad Junction photodetector (BQJ), which can reduce both: the number of photodetectors and the area needed for multiwavelength pulse oximetry. With this type of photodetector, it is also possible to continuously estimate oxygen saturation without the need of pulsating LEDs.

Improvement of a FPGA-based Detection of QRS Complexes in ECG Signal using an Adaptive Windowing Strategy

This paper presents an FPGA-based algorithm for automatic detection of QRS complexes in ECG signals, first step for the estimation of cardiac intervals. The proposed algorithm is divided into 3 parts : Filtering, Contrast Enhancement, and finally a Detection block based on an adaptive windowing and a thresholding of the enhanced data. The entire detection scheme was developed in accordance with embedding constraints and in the perspective of a real-time use. We evaluated the algorithm on manually annotated databases, such MIT-BIH Arrythmia and QT databases. The FPGA-based algorithm correctly detects 91,85 % percent of the QRS complexes, with a very limited ratio of false detection (only 5%) on standard databases, while for realtime records obtained from young subjects between 20 and 25 years, the sensitivity reaches 93,77 % with a false detection ratio of only 4 %. These results are in accordance with the most recent state-of-the-art off-line algorithms on the same database, and improves significantly FPGA-based ones that were tested on a limited number of ECG extracted from the MIT-BIH set of data only.