Files
Sylpheed/docs/re/structures/plate-pulse-phase-lock.md
sylph-decoder 27ce59b3a7 re: the sweep IS drawn on the JP title -- and my gate was phase-locking the shutter
The occlusion hypothesis is refuted: build 7 draws the same three ROT strips at
higher alpha than English, so there was never an absence to explain.

The 0.32-vs-11.9 tension that motivated it was an artefact of my own instrument.
Both JP captures were shuttered on the plate pulse, and the plate's pulse is part
of the animation -- so the gate synchronises the shutter to the animation's phase.
Measured at the shutter instant, the sweep sits 25-26 px apart across two runs in
different locales and different sessions: 1.6 % of a ~1600 px traverse.

So the 0.32 I recorded as between-session capture noise measures my trigger's
repeatability, and I read it as evidence the title is still when it is evidence
the gate works. The era adjudication is unaffected -- margin 16.72 clears even the
un-locked 11.9 -- and unaffected for the reason that file already gave: correlated
noise cancels in a margin.

Refutation attempt on sylpheed-port's positional-mechanism rejection: FAILED, the
claim stands. Its residual sits inside lit logos, and the logo ROI is
byte-identical across five differently-phased frames in two sessions.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
2026-08-30 19:52:15 +00:00

3.2 KiB
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The plate-pulse gate phase-locks the shutter to the title animation

measured — 2026-08-30 · data · instrument tools/re-capture/jp_draw_capture.sh, control the English title draw log

The claim

wait_plate_pulse.py waits for the title plate's glyph count to sit in [500, 2500] for 12 samples, and every title capture in this corpus shutters on it. It was adopted to answer "has the screen settled?" — and it does.

But the plate's pulse is part of the title's animation, so gating on it does not only wait for settling: it synchronises the shutter to the animation's phase. Two runs gated this way are not two samples of a free-running clock.

The measurement

The x of each tall ROT strip at the first captured frame — the shutter instant — in two independent runs, different sessions, different locales:

strip EN run JP run apart
883×1134 x = −109 x = −83 26 px
1299×1303 x = 486 x = 461 25 px

Against a traverse of ~1600 px, that is 1.6 %. Two boots, two locales, two sessions, and the sweep is in essentially the same place both times.

What it invalidates — my own reading

jp-title-at-rest.txt reasons that its second capture probes a new axis, "BETWEEN runs, where a free-running clock lands somewhere else on a fresh boot", and reports RMSE 0.32 in the era box as the between-session capture noise.

🔴 The clock does not land somewhere else. The gate puts it back in the same place. So:

  • 0.32 is a phase-locked LOWER BOUND on capture noise, not capture noise. At an arbitrary phase the in-box figure is the 11.9 measured between two EN captures a plateau-phase apart. Anything reusing 0.32 as "the noise floor" is quoting the gate, not the game.
  • I read the 0.32 as evidence the JP title is still. It is not. It is evidence the gate works. I had it backwards.
  • The whole-frame 116 492 px that do differ between those two sessions are consistent with exactly this: ~25 px of residual jitter displacing two large bright diagonal strips moves a lot of pixels globally while barely clipping the era box.

What it does NOT invalidate

✅ The era adjudication stands. Its margin is 16.72 (41.69 fixed vs 58.41 stale), which exceeds even the un-locked 11.9 figure — so it survives whichever noise number is correct. And the file's own key insight is untouched and is the reason it survives: capture noise moves both candidates together and nearly cancels in a margin (absolute scores moved 0.001–0.002 between sessions; the margin moved 0.001).

✅ The within-run at-rest result stands — five frames ~1.5 s apart are not gated individually, so they sample different phases, and the logo ROI is byte-identical across them in both sessions while 5–8 % of the frame moves.

Reach of the negative

This says the gate locks phase; it does not say by what mechanism. Both runs boot the same ISO from the same state, so the pulse may simply occur at a fixed offset from a deterministic boot rather than the gate doing the locking. Two runs deliberately shuttered at different phases would separate those and were not run.