Slow Trends - A Problem in Analysing Pupil Dynamics
Christoph Strauch, Juliane Georgi, Anke Huckauf, Jan Ehlers · 2015
As of recently, research efforts are intensified to operationalize pupil dynamics for cognitive and affective classification in human-machine interaction. However, signal analysis of pupil diameter changes is problematic since the respective dynamics consist of three essential components that have to be disentangled: Very slow diameter changes, slow and high frequencies. The current paper discusses the amount of slow trends in pupillary signal courses and the effects on functional parameters of pupil dilations. Thereby we confront our data with linear detrending approaches and reveal various forms of trend progressions that differ over time and cannot be fixed with conventional linear procedures.