Optimization of Lacrimal Aspect Ratio for Explainable Eye Blinking

Eye blinking has been studied extensively due to its wide range of potential applications. However, one under-researched field is the use of the wider lacrimal area for detection. This paper proposes a new eye blinking detection method using a novel lacrimal aspect ratio (LAR) strategy that utilises eyebrow movement and eyes. The proposed algorithm estimates facial landmarks using an automatic facial landmark detector to extract a single scalar quantity by using LAR and characterizing eye opening and closing, and to detect both partial and full blinking in each frame using a LAR threshold. We set three threshold values, –2.4 and –2.6, and –2.9, to detect blinks by each frame. Experimental results show that our approach successfully detects eye blinks and can outperform other state-of-the-art works. The utilization of LAR in detecting blinks and partial blinks demonstrates its potential to offer a novel and informative metric for researchers. This approach also opens up possibilities for further eye-related investigations, including the recognition of emotions. With its low dimensionality and easily understandable time domain features, LAR provides an effective pathway towards achieving these goals.