By default SCAN recognition distance is 80 pixels. That amounts to about 5 feet. You can reduce this to 20px but anything below 80 means you are lowering the recognition accuracy and so it is generally not recommended. Note that when we say "80 pixels", that is with a 25% padding around the face. So actual face size is 53 pixels ear to ear. But values given to SAFR need to be in the 25% padded values.
SAFR SCAN also has control over the face detection size. By default scan detects a face at about 8 or 9 feet which should be more than enough. The controls for face detection for scan are using the high sensitivity detector (detector.detect-faces-input-size=small, normal or large).
Below is information for recognition thresholds at different distances.
You can adjust the recognizer.minimum-face-size in "Advanced Feed Configuration" editor (from Within Video Feeds Window). Following values produce the corresponding results:
- 20px - 9.5' (max range)
- 100px - 4.5 ft
- 150px – 36”
- 180px – 34”
- 250px - 25”
- 300px - 17”
- 350px– 14”
- 400px - 12"
To adjust detection size, use detector.minimum-required-face-size.