description
Distracted-walking safety rule: detect a person who is USING A PHONE (per-frame using_phone_scores from the PAR attribute SGIE) AND MOVING (accumulated travel >= movement_ratio x average bbox width) at the same time. A confirmation window opens when the phone is first seen inside a monitored zone (cam_zones); at window close the rule decides on the accumulated evidence (deferred emission — one clean event with the full clip, not per-frame spam). Per-track, fire-once. The combination matters: phone-while-stationary is allowed (break areas), walking-without-phone is allowed — only the combination fires.
use cases
- no-phone-while-walking policies on factory / warehouse floors and forklift aisles
- pedestrian-safety zones where distracted walking is a struck-by hazard
- template for any attribute+motion combination rule (attribute gate x travel gate over a window)
limitations
- phone signal is a classifier score on the person crop — small/occluded phones lower recall
- needs the PAR SGIE attached to the person detector in the pipeline
- zone polygons required to scope enforcement (whole-frame monitoring is noisy)
config parameters
general
| Parameter | Type | Default | Notes |
|---|---|---|---|
| target_class | array of string | ["person"] | |
| cam_zones | array of array of pair of number | — | |
| phone_threshold | number | 0.85 | score above this = t0 trigger / full vote |
| phone_ratio | number | 0.4 | weighted phone ratio over window must exceed this |
| confirmation_seconds | number | 7.0 | |
| padding_seconds | number | 3.0 | |
| movement_ratio | number | 4.0 | travel >= this x avg bbox width |
golden replay cases
| Case | Frames | Expected events |
|---|---|---|
| phone-while-moving | 8 | 1 |