[SESSION_127] ZoneAnalyzer: Improve Bounding Box Overlap Detection (Phase 23)

Feature: Full Bounding Box Overlap Detection

Component: ZoneAnalyzer (/nodes/behavior_nodes/zone_analyzer/)
Severity: 🟠 HIGH
Session: SESSION 127 (Definition of Done)
Current Status: Uses bbox center only for containment
Target Phase: Phase 23

Context

Zone detection accuracy is compromised by center-point-only testing. When a person's bounding box center crosses a zone boundary, the person may be 30-50% outside the zone but is marked as "inside".

Requirements

• Check if entire bounding box overlaps zone polygon
• Not just center point containment
• Handle partial overlaps and edge cases
• Maintain performance (<100ms per frame)

Impact

Without this feature:

• False positives for zone entries
• Accuracy reduced (especially at boundaries)
• Inaccurate dwell time tracking
• Violation reporting unreliable

Effort Estimate

• Bbox-polygon intersection: 1.5-2 hours
• Testing with edge cases: 1-1.5 hours
• Total: 2-3 hours

Technical Approach

• Shapely bbox-polygon intersection
• Overlap threshold (e.g., >50% for "inside")
• Edge case handling (partial occlusion)

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Generated by SESSION 127 FASE 2.7