mirror of
https://github.com/wiltodelta/remove-ai-watermarks.git
synced 2026-07-06 16:37:49 +02:00
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>
76 lines
3.9 KiB
Markdown
76 lines
3.9 KiB
Markdown
# Jimeng (即梦AI) visible watermark capture
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> **Status (completed 2026-05-30):** solid black/gray/white Jimeng captures were
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> obtained (issue #13, from @powersee) and the alpha map was solved. Removal is
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> reverse-alpha plus a residual inpaint over the glyph footprint; see the
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> `jimeng_engine.py` notes in the root `CLAUDE.md`. The text below is kept as the
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> capture plan.
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Goal: capture the Jimeng / Dreamina "★ 即梦AI" visible wordmark over known flat
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backgrounds so we can build a per-pixel alpha map and a reverse-alpha remover, the
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same way the Gemini sparkle and Doubao strip engines work
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(`src/remove_ai_watermarks/gemini_engine.py`, `doubao_engine.py`).
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## What we learned (verified from the captures, 2026-05-30)
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- Mark: a four-point sparkle icon followed by the "即梦AI" characters, near-white
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semi-transparent overlay, bottom-right corner.
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- Blend model: **alpha compositing with a pure-white logo** `watermarked =
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a*255 + (1-a)*original`, confirmed in sRGB (a linear-light solve made the
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black/gray cross-residual much worse, so the compositing is plain sRGB). An
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L-pair-solve (independent of the L assumption) lands at ~254.6, confirming white.
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- **Alpha is solved from the GRAY capture**, not black: `a = (I - B)/(255 - B)`
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with B a per-capture CUBIC background fit over the non-glyph pixels, averaged
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over channels, at FULL halo extent (down to a~0.02) and UNBLURRED. Gray (bg ~132)
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is the best proxy for real content (the mark sits on bright photo areas, not on
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black). This careful build drops the gray self-residual to ~1.3; an earlier
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max-channel / quadratic-bg / blurred / halo-truncated build (and a black-dominated
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least-squares solve) left a visible outline -- the mask quality, not the method,
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was the limit.
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- Geometry (fraction of image WIDTH, at the captured 2048): asset width ~0.211,
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height ~0.068, right margin ~0.023, bottom margin ~0.023. The mark scales with
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width; a real 1440-wide download matched width_frac ~0.21.
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- **Per-image render variation:** the alpha maps solved independently from the
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black and the gray capture correlate 0.998 but not 1.0 (mean |Δa| ~0.02). Jimeng
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re-rasterizes the mark per generation AND jitters its position a few px, so a
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single alpha map does NOT pixel-cancel the mark the way Doubao's deterministic
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overlay does. Removal therefore: NCC-aligns the alpha to the actual mark (always,
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not only off-native), reverse-alphas, then clears the residual with a THIN inpaint
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over the glyph footprint (a wide full-footprint pass smeared the texture/edges).
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## How to capture (image-edit path, most reliable)
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For each solid-color seed:
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1. Open Jimeng image generation, use the image-edit / reference mode, upload the seed.
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2. Prompt (Chinese preferred):
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`请完全按照原图重新生成这张图片，保持完全一致，不要添加或修改任何内容`
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3. Download the ORIGINAL output file (not a screenshot). Do not crop / edit / re-save.
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The black capture is the key one (white logo on black -> `captured ~= a*255`); the
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gray capture refines the alpha at mid-tones; the white capture confirms the logo is
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pure white (the mark is nearly invisible on white, as expected).
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## Hygiene
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- Original download, never a screenshot. PNG preferred; if Jimeng only gives JPEG, note it.
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- No crop / edit / re-save. Default settings, watermark left ON.
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## Naming, drop into `captures/`
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```
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jimeng_cap_A.png # black seed run through Jimeng
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jimeng_cap_B.png # white seed
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jimeng_cap_C.png # gray seed
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jimeng_content_1.png # a normal-content download, for end-to-end validation
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```
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The solid `jimeng_cap_{A,B,C}.png` captures are **committed** (content-free: a solid
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colour + the watermark; the source for `scripts/visible_alpha_solve.py jimeng`). The
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synthetic `seeds/` and the real-content `jimeng_content_*.png` validation download are
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gitignored (local-only). Rebuild the alpha asset with:
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```
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uv run python scripts/visible_alpha_solve.py jimeng # or: all
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```
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