Files
mule-image/backend/app/services/vision/classify.py
dtoro fa9b21856f feat: replace face pipeline with InsightFace, add content classifier
Face detection/recognition:
- Replace YuNet + SFace with InsightFace buffalo_l (RetinaFace + ArcFace)
- 512-d ArcFace embeddings (was 128-d SFace), migration 0006 resizes column
- Remove YOLO person-bbox workaround — RetinaFace is accurate enough
- Detection threshold 0.65 cleanly separates real faces (0.72+) from
  false positives on dogs/paintings (0.56-0.61)

Content-type classification:
- CLIP zero-shot classifier using native PyTorch text encoder + ONNX
  image encoder for high-quality text-image similarity
- Categories: photograph, screenshot, document, receipt, meme, artwork
- Writes Tag(kind=content_type) per photo via photo_tags
- Margin-based confidence: top-1 vs top-2 score difference
- New ClassifierSettings in config (enabled, min_confidence)
- Wired into vision_fanout pipeline

Tested: 6 real faces from 4 photos (zero false positives), 11/13 photos
classified (8 photograph, 2 artwork, 1 meme).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-10 13:49:02 +02:00

107 lines
3.5 KiB
Python

"""
CLIP zero-shot content-type classifier.
Uses the native OpenCLIP PyTorch text encoder for high-quality text
embeddings (the ONNX text encoder has degraded quality due to the
eot_indices workaround). Image embeddings use the ONNX visual encoder
which works well.
"""
import logging
import numpy as np
import torch
from app.config import VisionSettings
from app.services.vision.base import ContentClassifier, ClassificationResult
logger = logging.getLogger(__name__)
CATEGORY_PROMPTS = {
"screenshot": [
"a screenshot of a computer screen",
"a screenshot of a phone screen",
"a screen capture of a user interface",
],
"document": [
"a scanned document",
"a photo of a document with printed text",
"a photo of a page of text on paper",
],
"receipt": [
"a photo of a receipt",
"a photo of a bill or invoice",
],
"meme": [
"an internet meme with text overlay",
"a funny image with caption text",
],
"artwork": [
"a painting or drawing",
"a sketch or illustration",
"digital art or graphic design",
],
"photograph": [
"a photograph taken with a camera",
"a real photo of a real scene or person",
"a candid photograph",
],
}
class CLIPContentClassifier(ContentClassifier):
"""Zero-shot content classifier using CLIP text-image similarity.
Uses native PyTorch for text encoding, ONNX for image encoding."""
def __init__(self, settings: VisionSettings):
import open_clip
self._min_confidence = settings.classifier.min_confidence
# Load native model for text encoding only
logger.info("Loading OpenCLIP text encoder for content classification")
model, _, _ = open_clip.create_model_and_transforms(
"ViT-B-32", pretrained="laion2b_s34b_b79k"
)
model.eval()
self._model = model
self._tokenizer = open_clip.get_tokenizer("ViT-B-32")
# Get the ONNX image embedder from the registry
from app.services.vision.registry import registry
self._embedder = registry.get_embedder()
# Pre-compute text embeddings for each category
self._category_embeddings: dict[str, np.ndarray] = {}
for category, prompts in CATEGORY_PROMPTS.items():
tokens = self._tokenizer(prompts)
with torch.no_grad():
text_features = model.encode_text(tokens)
text_features /= text_features.norm(dim=-1, keepdim=True)
avg = text_features.mean(dim=0)
avg /= avg.norm()
self._category_embeddings[category] = avg.numpy().astype(np.float32)
logger.info("Content classifier ready with %d categories", len(self._category_embeddings))
def classify(self, image: np.ndarray) -> list[ClassificationResult]:
img_vec = self._embedder.embed_image(image)
# Cosine similarity against each category
scores = {}
for category, cat_vec in self._category_embeddings.items():
scores[category] = float(np.dot(img_vec, cat_vec))
# Sort by score descending
ranked = sorted(scores.items(), key=lambda x: -x[1])
best_cat, best_score = ranked[0]
second_score = ranked[1][1]
margin = best_score - second_score
# Normalize: 0.01 margin → ~0.5 confidence, 0.03+ → ~1.0
confidence = min(1.0, margin * 30)
if confidence >= self._min_confidence:
return [ClassificationResult(label=best_cat, confidence=confidence)]
return []