Lower seg_loose_threshold to 0.08

Route faint hair (BiRefNet M 0.08-0.15) into the unknown band instead of sure
background, giving ViTMatte a chance at it. On its own this does not recover the
green-contaminated shoulder wisps: those are ~pure green (dominance +0.88, like
the screen) so ViTMatte cuts them regardless of trimap -- that is handled by the
upcoming segmentation dropout-fill. The finger gap (M~0.02) stays sure background.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

bgfilter/settings.py

@@ -27,7 +27,7 @@ class TrimapSettings:
     min_fg_safe_radius: int = 2
     # Semantic fusion thresholds (used by fuse_trimap when segmentation is on).
     seg_core_threshold: float = 0.60
-    seg_loose_threshold: float = 0.15
+    seg_loose_threshold: float = 0.08
 
 
 @dataclass(frozen=True)

configs/default.yaml

@@ -16,7 +16,7 @@ trimap:
   unknown_radius_ratio: 0.012
   fg_safe_radius_ratio: 0.006
   seg_core_threshold: 0.60
-  seg_loose_threshold: 0.15
+  seg_loose_threshold: 0.08
 
 alpha_post:
   chroma_suppress: true