Spectral Repeatability of a Hyperspectral System for Human Iris Imaging

Abstract

The present study was conducted to evaluate the measuring performance of a prototype hyperspectral imaging system. This instrument was developed to measure the human iris spectral reflectance in vivo. Several previous works highlighted how changes in the iris pigmentation and morphology may provide an indication of the development and progression of certain eye pathologies. The use of hyperspectral imaging could aid physicians in the early detection of such diseases, by exploiting both the spatial and spectral features that this optical technique is able to collect. We evaluated the measurements repeatability from images acquired across 22 spectral bands in the visible and near-infrared range (480 - 900 nm), from 8 healthy volunteers. Moreover, we assessed the intra- and inter-session repeatability of the quantitative hyperspectral measurements. Repeatability was lower for darker irises and for wavelengths from 520 to 900nm. In particular, the coefficient of repeatability (95% of confidence interval) for measurements between sessions was ±10% and ±5% for dark and light irises, respectively. The within session repeatability was ±7.5% and ±4%, respectively. The obtained repeatability coefficients confirm the reliability and reproducibility of the hyperspectral data collected by our system.