Jonny Kuo1, Sjaan Koppel2, Judith L Charlton2, Christina M Rudin-Brown3. 1. Monash University Accident Research Centre (MUARC), Monash University, Australia. Electronic address: jonny.kuo@monash.edu. 2. Monash University Accident Research Centre (MUARC), Monash University, Australia. 3. Human Factors North, Inc., 174 Spadina Avenue, Suite 202, Toronto, Ontario, Canada.
Abstract
INTRODUCTION: Internal driver events such as emotional arousal do not consistently elicit observable behaviors. However, heart rate (HR) offers promise as a surrogate measure for predicting these states in drivers. Imaging photoplethysmography (IPPG) can measure HR from face video recorded in static, indoor settings, but has yet to be examined in an in-vehicle driving environment. METHODS: Participants (N=10) completed an on-road driving task whilst wearing a commercial, chest-strap style heart rate monitor ("baseline"). IPPG was applied to driver face video to estimate HR and the two measures of HR were compared. RESULTS: For 4 of 10 participants, IPPG produced a valid HR signal (±5 BPM of baseline) between 48 and 75% of trip duration. For the remaining participants, IPPG accuracy was poor (<20%). CONCLUSIONS: In-vehicle IPPG is achievable, but significant challenges remain. PRACTICAL APPLICATIONS: The relationship between IPPG accuracy and various confounding factors was quantified for future refinement.
INTRODUCTION: Internal driver events such as emotional arousal do not consistently elicit observable behaviors. However, heart rate (HR) offers promise as a surrogate measure for predicting these states in drivers. Imaging photoplethysmography (IPPG) can measure HR from face video recorded in static, indoor settings, but has yet to be examined in an in-vehicle driving environment. METHODS:Participants (N=10) completed an on-road driving task whilst wearing a commercial, chest-strap style heart rate monitor ("baseline"). IPPG was applied to driver face video to estimate HR and the two measures of HR were compared. RESULTS: For 4 of 10 participants, IPPG produced a valid HR signal (±5 BPM of baseline) between 48 and 75% of trip duration. For the remaining participants, IPPG accuracy was poor (<20%). CONCLUSIONS: In-vehicle IPPG is achievable, but significant challenges remain. PRACTICAL APPLICATIONS: The relationship between IPPG accuracy and various confounding factors was quantified for future refinement.