FAQ: Why are there question marks (???) next to the Pupil or CR values?

[SR-SUPPORT]

Seeing question marks (e.g., Pupil: ???) next to the Pupil or Corneal Reflection (CR) values in Head Fixed mode means the auto-threshold process failed and the system is using the last known settings as a fallback. Please note that the question marks do not indicate that the thresholds are "bad", it simply indicates that the last known "good" values are being used.

The question marks may appear if the participant blinks or moves their eye at the exact moment the auto-threshold is calculated.

Follow these steps to set the correct thresholds:

1. Retry Auto-Threshold
   • Ask the participant to look straight ahead and keep their eyes open.
     
   • Trigger the auto-threshold function again.
     
   Often, a simple retry is all that is needed. However, you should always manually fine-tune the results.
   
   
2. Manually Adjust Thresholds
   The auto-threshold feature is only intended to get you close to the optimal values. When tracking in Head Fixed mode, always make manual adjustments for the best results.
   • Pupil Threshold: Use the ↑ and ↓ arrow keys.
     
   • CR Threshold: Use the + and - keys.
     
3. Adjust Illuminator Power (If Needed)
   If the threshold values seem too high or low after the automatic process, you may need to adjust the illuminator power.
   • If CR value is too high (e.g., > 230): Decrease the illuminator power.
     
   • If Pupil value is too low (e.g., < 75): Increase the illuminator power.
     
   After adjusting the illuminator, run the auto-threshold again and then fine-tune the values manually.
   

The auto-threshold function is intended to find Pupil and CR threshold values that are close to an acceptable range, but the thresholds should always be adjusted manually to achieve the optimal values. Please see the following thread for detailed instructions on adjusting thresholds to their optimal values.