# Background-colour prior. null = auto-detect the flat background colour from the
# image border (raises if the border is not one clean flat colour). A hex string
# like "#CFEFFF" sets it explicitly. Also overridable via --screen-color.
screen_color: null

model:
  model_name: hustvl/vitmatte-base-composition-1k
  device: cpu
  matting_method: vitmatte
  fallback_to_chroma_alpha: false

segmentation:
  # enabled: true  = single-segmenter pipeline (one seg model drives the trimap)
  # enabled: false = no seg model, chroma-only pipeline (Chroma + ViTMatte)
  enabled: true
  backend: birefnet           # single trimap segmenter; switchable at runtime: --seg-backend birefnet|anime-seg
  model_name: ZhengPeng7/BiRefNet  # matches backend; --seg-backend anime-seg auto-selects skytnt/anime-seg
  device: cpu
  input_size: 1024

trimap:
  sure_bg_threshold: 0.92
  sure_fg_threshold: 0.12
  unknown_radius_ratio: 0.012
  fg_safe_radius_ratio: 0.006
  seg_core_threshold: 0.60
  seg_loose_threshold: 0.08
  # Trimap mode (segmentation pipeline only; also settable via --trimap-mode):
  #   directional          = chroma + seg + hue split; background-hued residual
  #                          (blue between hair) -> unknown, white shirt kept. (default)
  #   seg                  = original fuse_trimap (no hue split).
  #   directional-hard-bg  = hard-remove background-hued pixels (aggressive; can eat
  #                          cool/shadowed white cloth).
  mode: directional
  seg_low: 0.15
  bg_hue_proj_min: 4.0

alpha_post:
  chroma_suppress: true
  chroma_suppress_bg_low: 0.35
  chroma_suppress_bg_high: 0.80
  chroma_suppress_strength: 1.0
  # Matte-confidence gate: suppression fades where ViTMatte's raw alpha is high
  # (ramp lo -> hi), so colour evidence only vetoes the matte where it is unsure.
  # Set suppress_raw_lo: 1.0 to disable.
  suppress_raw_lo: 0.85
  suppress_raw_hi: 0.98

cross_check:
  # Cross-model veto: a second, trimap-free matting model may only LOWER alpha
  # (min-fusion), only on background-hued bright pixels the primary result is
  # confident about — clears colour-drifted background residue between hair
  # strands that chroma, segmentation and ViTMatte all read as foreground.
  # Costs one extra model (~0.9 GB download) and one inference pass per image.
  # Disable with enabled: false or --no-cross-check.
  enabled: true
  model_name: ZhengPeng7/BiRefNet_HR-matting
  input_size: 2048
  proj_min: 3.0        # bg-hue projection above which a pixel is suspect
  l_min: 45.0          # Lab lightness below which a pixel is exempt (dark hair)
  feather_sigma: 2.0   # zone-boundary feather, px
  gate_lo: 0.70        # primary alpha below this -> fully exempt
  gate_hi: 0.95        # primary alpha above this -> fully vetoable

foreground:
  enabled: true
  method: ml
  fallback_to_unmix: true
  ml_regularization: 0.00001
  # Legacy "unmix" method params (used only when method: unmix).
  edge_low: 0.005
  edge_high: 0.995
  min_unmix_alpha: 0.08
  unmix_strength: 0.70
  local_strength: 0.45
  local_blur_radius: 11
  local_alpha_threshold: 0.92
  local_bg_confidence_max: 0.20
  green_excess_margin: 0.015
  bg_confidence_weight: 0.70

despill:
  enabled: true
  edge_low: 0.005
  strength: 0.92
  edge_expand_radius: 2
  alpha_weight_floor: 0.35
  color_margin_lab: 4.0    # Lab chroma margin along the background-colour direction