Victor Kuznetsov
e572767555
Visible-watermark work across all three corner-mark engines plus a committed,
reproducible alpha-build pipeline (scripts/visible_alpha_solve.py) fed by committed
solid black/gray/white captures.
- jimeng: new "即梦AI" wordmark remover (reverse-alpha + thin residual inpaint,
always NCC-aligned -- the mark re-rasterizes/jitters per image). Detect via glyph
silhouette NCC (0.45 threshold; does not cross-fire with Doubao). Registered in the
visible-mark catalog; `visible --mark jimeng` / `--mark auto`.
- doubao: fix a real production defect -- the shipped remover left a READABLE
"豆包AI生成" outline on real samples while detect() returned conf 0.0 (fooled by a
thin outline), so the test passed and the "56/56 clean" claim was detector-measured,
not visual. Root cause: under-estimated alpha + fixed-geometry-no-inpaint + tight
locate box. Rebuilt alpha (careful gray-self solve), always-align, thin inpaint,
widened locate box -> readable outline becomes faint texture-level traces.
- gemini: rebuild gemini_bg_{96,48} from our own controlled captures (validated NCC
0.9998 vs the prior third-party asset); removal re-verified clean, no behaviour change.
- tests: add textured-shift regression to both engines (guards the align-on-shift path
the Doubao defect exposed; lesson: a detector-only removal test is insufficient,
assert visual residual).
- docs: CLAUDE.md, README, capture READMEs and docstrings synced; stale
"exact/pixel-exact/56-clean" claims removed.
Also includes a SynthID label-wording clarification in identify.py/cli.py
("SynthID pixel watermark" -> "SynthID watermark, inferred from C2PA metadata").
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Gemini (Nano Banana) visible sparkle capture
Status (captured 2026-05-31): black/gray/white captures taken and committed in
captures/(solid colour + the sparkle, content-free). The sparkle-on-black assetsgemini_bg_{96,48}.pngare rebuilt byscripts/visible_alpha_solve.py gemini.
Google Gemini (Nano Banana) stamps a four-point sparkle icon in the bottom-right corner
via alpha compositing: watermarked = a*logo + (1-a)*original. Unlike the Doubao/Jimeng
text marks, the sparkle is captured over a pure-black background, where
watermarked = a*255 (logo is near-white), so the alpha reads directly off the capture
(alpha = max(R,G,B)/255) -- no background fit needed. This is the "golden" capture case.
What the captures confirmed (2026-05-31)
- The sparkle at a 2048-wide image is 96x96 px (width_frac ~0.047), bottom-right, margins ~0.031, alpha max ~0.51 -- matching the engine's existing 96px asset.
- Our own controlled capture matches the previously third-party-sourced
gemini_bg_96.pngto NCC 0.9998, so the bundled asset is validated and now reproducible from our own capture.
How to capture (image-edit path)
For each solid-colour seed (seeds/seed_{black,gray,white}_2048.png, gitignored):
- Open Gemini image generation, image-edit / reference mode, upload the seed.
- Prompt:
Recreate this image exactly as it is, keep it identical, do not add or change anything - Download the ORIGINAL output (not a screenshot). Do not crop / edit / re-save.
Black is the key one (sparkle on black -> exact alpha). Gray/white cross-check.
Naming, drop into captures/
gemini_black_2048.png # the key capture (sparkle on black)
gemini_gray_2048.png
gemini_white_2048.png
The solid captures are committed (content-free). The synthetic seeds/ and any
real-content gemini_content_*.png validation download are gitignored (local-only).
Rebuild the assets with:
uv run python scripts/visible_alpha_solve.py gemini # or: all