Open AccessGeometrical-optics approach to increase the accuracy in LED-based photometers for point-of-care testing
Author(s) -
Marco Giuseppe Ajmone Marsan,
Massimiliano Lucidi,
Francesco Pudda,
Mattia Pirolo,
Emanuela Frangipani,
Paolo Visca,
Gabriella Cincotti
Publication year - 2019
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.10.003654
Subject(s) - optics , stray light , attenuation coefficient , refractive index , photometer , attenuation , refraction , materials science , physics
A geometrical-optics approach is proposed to increase the accuracy in photometric measurements, using a point-of-care testing (POCT) LED-based sensor. Due to stray-light effects, the measurement accuracy depends on the dimension of the CMOS area, where the radiation is detected. We propose two image processing approaches and evaluate the influence of the sensor area. In addition, we demonstrate that with the same measurement, both absorption coefficient and refractive index can be determined, measuring the beam attenuation and the spot-size enlargement due to ray refraction.