ruvnet--ruview/examples/research-sota/06-structure-detection

06 — Structure detection (R12 arc, 3 ticks)

Detecting "something new in the room" — new furniture, intruder, fallen person. Three-tick arc: R12 NEGATIVE → R12 PABS POSITIVE → R12.1 closed loop.

Scripts (in arc order)

Script	Thread	Headline	State
r12_rf_weather_eigenshift.py	R12	Naive SVD-spectrum cosine distance: 0.69× signal/drift = undetectable. Fails because eigenshift is indistinguishable from natural drift.	NEGATIVE (missing-tool)
r12_pabs_implementation.py	R12 PABS	Physics-Anchored Background Subtraction: 1,161× signal/drift for unexpected occupant. ~100× lift over R12 NEGATIVE. Achieved by composing R6.1 forward operator as the PABS basis.	POSITIVE
r12_1_pose_pabs_loop.py	R12.1	Pose-aware closed loop: 9.36× intruder detection in dynamic scenes (false-alarm problem from R12 PABS resolved). Pose updates suppress subject-motion contribution 20×.	CLOSED LOOP

The arc summary

R12 (tick 5) → R12 PABS (tick 19) → R12.1 (tick 29): failure → success with caveat → success without caveat.

The arc validates the research-loop pattern: catalogue NEGATIVE results explicitly, then revisit them when better tools arrive. R6.1 multi-scatterer (tick 18) provided the tool that R12 was missing in tick 5.

How PABS works (R12 PABS implementation)

y_predicted = sum over voxels of  A(voxel) × reflectivity(voxel)
              where A is the R6.1 forward operator
PABS = ||y_observed − y_predicted||² / ||y_observed||²

If PABS > threshold:
    structural change detected (new scatterer in scene)

How the closed loop works (R12.1)

At each frame:
    pose_estimate = pose_tracker.estimate(csi_window)  // ADR-079 / ADR-101
    expected_scene = body_model.from_pose(pose) + walls
    y_predicted = R6.1.forward(expected_scene)
    PABS = ||y_observed − y_predicted||² / ||y_observed||²
    if PABS > threshold:
        emit_structure_event()

Subject motion is absorbed into the prediction; only unexplained residuals trigger structure events. This is the V0 security feature in R14 + R16/R17/R18 verticals.

Composition with other folders

• 01-physics-floor/r6_1_multiscatterer.py provides the A(voxel) forward operator
• 03-spatial-intelligence/r7_multilink_consistency.py provides per-link adversarial check
• 09-quantum-fusion/r20_1_quantum_classical_fusion.py composes structure detection with NV-magnetometer fusion

Production status (per PRODUCTION-ROADMAP.md)

• Tier 1.2: R12.1 pose-PABS in vital_signs cog (~80 LOC Rust)
• Tier 3.4: Standalone cog-fall-detection (~200 LOC)

See also

• Research notes: docs/research/sota-2026-05-22/R12-*.md, R12_1-*.md
• ADRs: ADR-079 (pose tracker), ADR-101 (cog-pose-estimation), ADR-029 (multistatic)