Pupil Threshold
The pupil threshold is a vital part of how Eye Precision tracks the movement of the pupil throughout the video
You can consider the pupil threshold to be "The maximum brightness that a part of the video can be to be considered a possible pupil
Any area of the video that is brighter than this maximum threshold will automatically be discounted when working out which part of the video should be tracked
The pupil threshold is therefore automatically set by Eye Precision by default, depending on the pupil marked by the user
Adjusting the threshold manually
In some cases, particularly with inconsistent lighting, the pupil threshold may need to be adjusted manually
When the pupil marking becomes too small or disappears on the results video, the pupil threshold is probably set too low - the pupil is visible, but too bright to be considered as a pupil by the processing
In this case you can adjust the pupil threshold up slightly and re-run the video processing
When the pupil marking becomes too large on the results video, it is often because the pupil threshold is too high, meaning brighter objects are being selected as possible pupils
When this happen, adjust the pupil threshold down slightly and re-run the video processing
Advanced settings
If you find that you are regularly having to adjust the pupil threshold upwards or downwards, you can change how the auto-threshold is set in the advanced settings in the menu
The auto-threshold multiplier can be adjusted for the goggles and smartphone modes separately