a6a313d2d0
Adds bgfilter/segmentation.py: BiRefNetSegmenter produces a soft subject mask that defines topology -- it includes colour-contaminated foreground (green-tinted hair) and excludes see-through holes (finger gaps), the distinction chroma/colour cues cannot make. Validated on both samples: green hair -> foreground, finger gap -> background, both correct. Foundation of the semantic-guided redesign; the mask will drive trimap construction next, with ViTMatte still refining soft edges. - SegmentationSettings (ZhengPeng7/BiRefNet, 1024 input, fp32). - Deps: torchvision, timm, einops, kornia. Weights load from HuggingFace via trust_remote_code; behind a firewall set HF_ENDPOINT=https://hf-mirror.com and bypass the proxy. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
74 lines
3.0 KiB
Python
74 lines
3.0 KiB
Python
from __future__ import annotations
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import numpy as np
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from PIL import Image
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from .settings import SegmentationSettings
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class BiRefNetSegmenter:
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"""Semantic subject segmentation via BiRefNet.
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Produces a soft foreground mask that defines subject *topology*: it includes
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colour-contaminated regions (e.g. green-tinted hair) as foreground and
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excludes see-through holes (e.g. gaps between fingers) as background -- the
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distinction that chroma/colour cues cannot make. The mask drives trimap
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construction; ViTMatte still refines the soft edges.
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Environment notes:
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- Weights load from HuggingFace. Behind a firewall set ``HF_ENDPOINT``
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(e.g. ``https://hf-mirror.com``); a flaky proxy may need to be bypassed.
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- The repo ships custom modeling code, so ``trust_remote_code=True`` is
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required (it executes that code -- only use a model source you trust).
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"""
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def __init__(self, settings: SegmentationSettings):
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try:
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import torch
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from torchvision import transforms
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from transformers import AutoModelForImageSegmentation
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except ModuleNotFoundError as exc:
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raise RuntimeError(
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"Missing segmentation dependencies. Install them with: "
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"pip install torch torchvision transformers timm einops kornia"
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) from exc
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self.torch = torch
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self.model = AutoModelForImageSegmentation.from_pretrained(
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settings.model_name, trust_remote_code=True
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)
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self.model.eval()
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self.model.float() # checkpoint ships as fp16; force fp32 to match inputs
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self.device = self._resolve_device(settings.device)
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self.model.to(self.device)
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size = settings.input_size
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self.transform = transforms.Compose(
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[
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transforms.Resize((size, size)),
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transforms.ToTensor(),
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transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]),
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]
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)
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def _resolve_device(self, requested: str):
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if requested == "cuda" and not self.torch.cuda.is_available():
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raise RuntimeError(
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"CUDA was requested but is not available. Use --device cpu or install a CUDA-enabled PyTorch build."
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)
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return self.torch.device(requested)
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def mask(self, rgb: np.ndarray) -> np.ndarray:
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"""Return a soft foreground mask, float32 0..1, at the input resolution."""
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image = Image.fromarray(rgb.astype(np.uint8), mode="RGB")
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tensor = self.transform(image).unsqueeze(0).to(self.device)
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with self.torch.no_grad():
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pred = self.model(tensor)[-1].sigmoid()
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pred = pred[0, 0].detach().float().cpu().numpy()
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if pred.shape != rgb.shape[:2]:
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pred_img = Image.fromarray(
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np.clip(pred * 255.0, 0, 255).astype(np.uint8), mode="L"
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).resize((rgb.shape[1], rgb.shape[0]), Image.Resampling.BILINEAR)
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pred = np.asarray(pred_img, dtype=np.float32) / 255.0
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return np.clip(pred, 0.0, 1.0).astype(np.float32)
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