Loop Closure Detection

Detect revisited locations to correct accumulated drift.

How It Works

1. Visual Similarity: Compare current frame with past keyframes
2. Geometric Verification: Verify spatial consistency
3. Pose Graph Update: Add loop closure constraint
4. Global Optimization: Minimize overall error

Loop Closure Detection

def detect_loop(current_frame, database):
    # Query visually similar frames
    candidates = database.query(current_frame, top_k=5)

    for candidate in candidates:
        # Geometric verification
        if verify_geometry(current_frame, candidate):
            return LoopClosure(current_frame, candidate)

    return None

Benefits

• Corrects accumulated drift
• Improves map consistency
• Enables long missions (hours)

Drift reduction: 2-5% → <1% with good loop closures

Configuration

loop_closure:
  enabled: true
  min_score: 0.7
  consistency_check: true
  max_candidates: 10

Next: Sensor Fusion