Eye blinks are measured by first calculating a variable called eye aspect ratio (EAR), which we get from here, and is basically just a quantification of how open the eye is. Over the course of a video, the EAR ends up being a vector whose troughs most likely signify individual eye blinks. The troughs are identified using a find peaks function and for each trough, the EAR value is outputted along with the other raw variables described below.
Raw Variables
| Variable | Description |
|---|
mov_blink_ear | Eye aspect ratio i.e. a vector derived from this model at points in the video where an eye blink was detected. |
mov_blinkframe | Eye blink times are indices of the video frames where an eye blink was detected. |
mov_blinkdur | Durations between blinks is the time spanned between the current blink and the previous blink in seconds. |
Derived Variables
| Variable | Description |
|---|
mov_blink_ear_mean | Eye aspect ratio mean i.e. the mean of the vector mov_blink_ear. |
mov_blink_ear_std | Eye aspect ratio standard deviation i.e. the standard deviation of the vector mov_blink_ear. |
mov_blink_count | Number of blinks measured over the course of the video. |
mov_blinkdur_mean | Mean duration between eye blinks measured in seconds. |
mov_blinkdur_std | Standard deviation of duration between eye blinks measured in seconds. |