Tick 27 — 2026-05-22 09:32 UTC

Thread: R6.2.5 (multi-subject occupancy union) Verdict: Clean positive — N=5 hits 100% coverage for households of 1-4 occupants with chest-centric zones. N=4 knee returns. R6 family completes with this tick.

What shipped

examples/research-sota/r6_2_5_multi_subject.py
examples/research-sota/r6_2_5_multi_subject_results.json
docs/research/sota-2026-05-22/R6_2_5-multi-subject-union.md

Headline

Scenario	# zones	Coverage @ N=5
1 occupant	1	100%
2 occupants	2	100%
3 occupants	3	100%
4 occupants	4	100%

4-occupant saturation curve:

N	Coverage
2	14.5%
3	72.9%
4	99.0% ← knee
5	100%

Knee at N=4 even for 4 occupants. The chest-centric small-zone approach generalises trivially.

Cross-eval: multi-subject optimisation matters

Placement	Coverage on 4 zones
Single-subject-optimised	70.6%
Multi-subject-optimised	100%
Gain	+29.4 pp

CLI must accept multiple --target args and compute union.

R6 family complete (9 ticks)

Tick	Config	Result
R6.2	2D body, single	51% N=5
R6.2.1	3D body, single	26% N=2
R6.2.2	2D body, N-anchor	97% N=5
R6.2.2.1	3D body, N-anchor	49% N=5
R6.2.3	2D chest, single	82% N=5
R6.2.4	3D chest, N-anchor	77/82% N=5/6
R6.2.5	2D chest, multi-subject	100% N=5

R6 family's ship recipe: 2D chest-centric + multi-subject + N=5 = 100% coverage.

Why N=4 knee returns for multi-subject

Each chest zone is 40×40 cm and fits inside one Fresnel ellipsoid (~40 cm wide at midpoint of 5 m link). N=4 anchors → 6 pairwise links → enough to cover 4 disjoint chest zones without much waste. Beyond N=4 the marginal gain drops to <1 pp.

Chest-centric multi-subject is the sweet spot for the Fresnel envelope geometry.

Final R6.2 CLI surface (productisation spec)

wifi-densepose plan-antennas
    --room W H [Z]                       # 2D or 3D
    --target NAME X Y W H [DX DY DZ]    # repeatable
    --target-mode {body, chest}          # R6.2.3
    --freq-ghz F                         # 2.4, 5.0, 6.0
    --n-anchors N                        # auto-saturation if omitted
    --restarts K                         # 4 default

~50 LOC over the original R6.2.

Composes with prior threads

R6.2 / R6.2.3: direct extension (single → multi)
R6.2.2 / R6.2.4: same saturation behaviour
R14: V1/V2/V3 in households of 2-4 use this recipe
R3 / ADR-024: per-subject identity + multi-subject placement = full empathic-appliance stack
ADR-105/106/107: federation orthogonal to placement
R12 PABS: multi-subject coverage = multi-subject intrusion detection

Honest scope

2D only (3D multi-subject is mechanical extension)
Static positions (real movement = conservative union)
Single 5×5 m geometry
Greedy + 4 restarts
4 occupants; beyond may degrade

Coordination

ticks/tick-27.md. No PROGRESS.md edit. Branch research/sota-r6.2.5-multi-subject.

Remaining loop work

R12.1: pose-PABS closed loop (needs Rust integration, out of scope for synthetic ticks)
ADR-108: Kyber substitution (quantum-resistant)
Loop retrospective / 00-summary.md (still ~2.5h until cron stop)

~2.5h to cron stop. 27 ticks landed. R6 family + R3 arc both substantively complete.