- chroma: drop BackgroundModel.hsv_center/hue_sigma (unused since the green gating
went away), their estimation, _hue_distance, and the now-unused hsv channel from
convert_color_spaces (one fewer cvtColor per image).
- despill: delete the dead green-channel-algebra path (the pipeline always passes a
colour) and fold the remaining Lab-direction despill into a single despill() with
no screen_color arg (127 -> 60 lines). Renamed despill_green -> despill.
- settings: remove the now-dead ChromaSettings.hue_sigma_min and
DespillSettings.green_excess_margin (plus the matching config lines).
- docs/comments: generalise stale "green" wording to "background colour" (module
docstring, alpha_post/trimap/foreground/settings) and rename the trimap variable
green_bg -> screen_bg.
Kept: the unmix foreground fallback, --matting-method chroma, and green/blue as
illustrative examples. Verified: package compiles, both configs parse, and an
auto-detect end-to-end run is unchanged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Strategic pivot: the dropout-fill rescue, the anime-seg fill backend, the
BiRefNet+anime-seg intersection, and the recolor pass all existed to repair
source images whose hair was already green-contaminated or broken at generation
time. Fixing the source instead (clean pastel-background generation) makes the
matte high-contrast, so that whole compensation layer is unnecessary. Remove it.
- Two pipelines via segmentation.enabled:
false -> chroma-only (Chroma + ViTMatte)
true -> single segmenter (default anime-seg, switchable birefnet) -> trimap
then ViTMatte refines, pymatting estimates foreground, despill cleans spill.
- Generalise the green-hardcoded colour logic to a screen_color prior (hex, e.g.
"#CFEFFF"; default null = green auto-detect, byte-identical). chroma keys off
Lab/RGB distance to the colour; despill removes chroma along its Lab direction.
Added --screen-color CLI flag.
- Removed dead code: fill_seg_dropouts + seg_fill*/intersection params,
SegmentationSettings.fill_backend/fill_model_name/sharpen, unsharp_mask,
recolor.py + RecolorSettings.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Green spill bleeds into pixels ViTMatte marks as solid foreground (alpha~1),
but despill was gated to the soft edge band (0.005<alpha<0.995) and weakened
exactly there: the alpha tent peaked at 0.5 and bg_confidence (low on the
character edge) further suppressed the correction.
- (1) Apply despill to the whole foreground (alpha > edge_low) instead of the
soft band only; neutral pixels stay untouched via the green-excess term.
- (2) Weight by alpha at full strength across the opaque range (alpha>=0.5),
easing off only where mostly transparent, instead of a tent peaking at 0.5.
- (3) Drop bg_confidence as a despill gate; localise purely by green excess.
Controlled comparison (same alpha, only despill changed), edge_green_excess:
ViTMatte TestImage p95 0.239->0.176, mean 0.131->0.061
ViTMatte TestImage2 p95 0.231->0.165, mean 0.115->0.052
Removes now-unused DespillSettings fields edge_high and bg_confidence_weight.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
lhk229
Codex