Files
logo_test/logo_detection_detr.py
Rick McEwen ea6fcec9ce Remove hybrid text+CLIP matching approach
The hybrid approach combined OCR text recognition with CLIP embeddings
to improve logo matching accuracy. After extensive testing, the approach
was abandoned because:

1. OCR quality on small logo crops is unreliable
2. Text filtering rejected correct matches as often as wrong ones
3. Best hybrid result (57.1% precision) was similar to baseline (55.1%)
4. Recall dropped significantly (52.6% vs 59.6%)
5. Added complexity (EasyOCR dependency, extra parameters) wasn't justified

Removed:
- Hybrid matching methods from DetectLogosDETR class
- Text extraction and similarity methods
- Hybrid test scripts and text_recognition.py module
- Hybrid-related CLI arguments from test_logo_detection.py

The baseline multi-ref matching with 0.70 threshold remains the
recommended approach for logo detection.
2026-01-08 12:48:39 -05:00

767 lines
29 KiB
Python

"""
Logo detection using DETR for object detection and vision models for feature matching.
This module provides a class for detecting logos in images using:
1. DETR (DEtection TRansformer) for initial logo region detection
2. Vision models (CLIP, DINOv2, etc.) for feature extraction and matching
The class supports caching of embeddings for efficient reprocessing.
The class automatically uses local models if available, otherwise falls back to HuggingFace.
Supported embedding models:
- CLIP models (openai/clip-vit-*): Text-image alignment, good general features
- DINOv2 models (facebook/dinov2-*): Self-supervised, excellent for visual similarity
"""
import json
import os
import torch
import torch.nn.functional as F
from transformers import pipeline, CLIPProcessor, CLIPModel, AutoImageProcessor, AutoModel
from PIL import Image
import cv2
import numpy as np
from pathlib import Path
from typing import List, Tuple, Dict, Optional, Any
class DetectLogosDETR:
"""
Logo detection class using DETR and vision embedding models.
This class detects logos in images by:
1. Using DETR to find potential logo regions (bounding boxes)
2. Extracting embeddings for each detected region (CLIP, DINOv2, etc.)
3. Comparing embeddings with reference logos for identification
The class automatically checks for local models before downloading from HuggingFace.
Supported embedding models:
- CLIP models (openai/clip-vit-*): Text-image alignment
- DINOv2 models (facebook/dinov2-*): Self-supervised visual features
"""
def __init__(
self,
logger,
detr_model: str = "Pravallika6/detr-finetuned-logo-detection_v2",
embedding_model: str = "openai/clip-vit-large-patch14",
detr_threshold: float = 0.5,
min_box_size: int = 20,
nms_iou_threshold: float = 0.5,
preprocess_mode: str = "default",
):
"""
Initialize DETR and embedding models.
The class will automatically check for local models in the default directories
before downloading from HuggingFace. You can override this by providing absolute
paths to local models.
Args:
logger: Logger instance for logging
detr_model: HuggingFace model name or local path for DETR object detection
embedding_model: HuggingFace model name for embeddings (CLIP or DINOv2)
detr_threshold: Confidence threshold for DETR detections (0-1)
min_box_size: Minimum width/height in pixels for detected boxes (filters noise)
nms_iou_threshold: IoU threshold for Non-Maximum Suppression
preprocess_mode: Image preprocessing mode for CLIP:
- "default": Use CLIP's default (resize shortest edge + center crop)
- "letterbox": Pad to square with black bars, preserving aspect ratio
- "stretch": Stretch to square (distorts aspect ratio)
"""
self.logger = logger
self.detr_threshold = detr_threshold
self.min_box_size = min_box_size
self.nms_iou_threshold = nms_iou_threshold
self.embedding_model_name = embedding_model
self.preprocess_mode = preprocess_mode
# Set device
self.device_str = "cuda:0" if torch.cuda.is_available() else "cpu"
self.device_index = 0 if torch.cuda.is_available() else -1
self.device = torch.device(self.device_str)
self.logger.info(f"Initializing DetectLogosDETR on device: {self.device_str}")
# Get default model directories from environment variables
default_detr_dir = os.environ.get('LOGO_DETR_MODEL_DIR', 'models/logo_detection/detr')
default_embedding_dir = os.environ.get('LOGO_EMBEDDING_MODEL_DIR', 'models/logo_detection/embedding')
# Resolve DETR model path (check local first, then use HuggingFace name)
detr_model_path = self._resolve_model_path(
detr_model, default_detr_dir, "DETR"
)
# Initialize DETR pipeline for logo detection
self.logger.info(f"Loading DETR model: {detr_model_path}")
self.detr_pipe = pipeline(
task="object-detection",
model=detr_model_path,
device=self.device_index,
use_fast=True,
)
# Resolve embedding model path
embedding_model_path = self._resolve_model_path(
embedding_model, default_embedding_dir, "Embedding"
)
# Check if this is a fine-tuned model
if self._is_finetuned_model(embedding_model_path):
self._load_finetuned_embedding_model(embedding_model_path)
else:
# Detect model type and initialize accordingly
self.model_type = self._detect_model_type(embedding_model)
self.logger.info(f"Loading {self.model_type} embedding model: {embedding_model_path}")
if self.model_type == "clip":
self.embedding_model = CLIPModel.from_pretrained(embedding_model_path).to(self.device)
self.embedding_processor = CLIPProcessor.from_pretrained(embedding_model_path)
else: # dinov2 or other transformer models
self.embedding_model = AutoModel.from_pretrained(embedding_model_path).to(self.device)
self.embedding_processor = AutoImageProcessor.from_pretrained(embedding_model_path)
if self.preprocess_mode != "default":
self.logger.info(f"Image preprocessing mode: {self.preprocess_mode}")
self.logger.info("DetectLogosDETR initialization complete")
def _detect_model_type(self, model_name: str) -> str:
"""Detect the type of embedding model based on name."""
model_name_lower = model_name.lower()
if "clip" in model_name_lower:
return "clip"
elif "dino" in model_name_lower:
return "dinov2"
else:
# Default to generic transformer for unknown models
return "transformer"
def _is_finetuned_model(self, model_path: str) -> bool:
"""Check if a model path points to a fine-tuned CLIP model."""
config_path = Path(model_path) / "config.json"
if config_path.exists():
try:
with open(config_path, "r") as f:
config = json.load(f)
return config.get("model_type") == "clip_logo_finetuned"
except (json.JSONDecodeError, IOError):
pass
return False
def _load_finetuned_embedding_model(self, model_path: str) -> None:
"""
Load a fine-tuned CLIP model from the training module.
Args:
model_path: Path to the fine-tuned model directory
"""
# Import the fine-tuned model class
try:
from training.model import LogoFineTunedCLIP
except ImportError as e:
self.logger.error(
f"Cannot import training.model for fine-tuned model: {e}"
)
raise ImportError(
"Fine-tuned model requires the training module. "
"Ensure the training/ directory is in your Python path."
) from e
# Load config
config_path = Path(model_path) / "config.json"
with open(config_path, "r") as f:
config = json.load(f)
base_model = config.get("base_model", "openai/clip-vit-large-patch14")
self.logger.info(f"Loading fine-tuned CLIP model from: {model_path}")
self.logger.info(f" Base model: {base_model}")
# Load model using the from_pretrained method
self.embedding_model = LogoFineTunedCLIP.from_pretrained(
model_path,
base_model=base_model,
device=self.device,
)
self.embedding_model.eval()
# Load processor from base model
self.embedding_processor = CLIPProcessor.from_pretrained(base_model)
# Set model type for embedding extraction
self.model_type = "clip_finetuned"
self.logger.info("Fine-tuned CLIP model loaded successfully")
def _resolve_model_path(
self, model_name_or_path: str, default_local_dir: str, model_type: str
) -> str:
"""
Resolve model path, checking for local models before using HuggingFace.
Args:
model_name_or_path: HuggingFace model name or absolute path
default_local_dir: Default local directory to check
model_type: Type of model (for logging, e.g., "DETR" or "CLIP")
Returns:
Resolved model path (local path or HuggingFace model name)
"""
# If it's an absolute path, use it directly
if os.path.isabs(model_name_or_path):
if os.path.exists(model_name_or_path):
self.logger.info(
f"{model_type} model: Using local model at {model_name_or_path}"
)
return model_name_or_path
else:
self.logger.warning(
f"{model_type} model: Local path {model_name_or_path} does not exist, "
f"falling back to HuggingFace"
)
return model_name_or_path
# Check if default local directory exists
if os.path.exists(default_local_dir):
# Verify it's a valid model directory (has config.json)
config_file = os.path.join(default_local_dir, "config.json")
if os.path.exists(config_file):
abs_path = os.path.abspath(default_local_dir)
self.logger.info(
f"{model_type} model: Found local model at {abs_path}"
)
return abs_path
else:
self.logger.warning(
f"{model_type} model: Local directory {default_local_dir} exists but "
f"is not a valid model (missing config.json)"
)
# Use HuggingFace model name
self.logger.info(
f"{model_type} model: No local model found, will download from HuggingFace: "
f"{model_name_or_path}"
)
return model_name_or_path
def detect(self, image: np.ndarray) -> List[Dict[str, Any]]:
"""
Detect logos in an image and return bounding boxes with CLIP embeddings.
Args:
image: OpenCV image (BGR format, numpy array)
Returns:
List of dictionaries, each containing:
- 'box': dict with 'xmin', 'ymin', 'xmax', 'ymax' (pixel coordinates)
- 'score': DETR confidence score (float 0-1)
- 'embedding': CLIP feature embedding (torch.Tensor)
- 'label': DETR predicted label (string)
"""
# Convert OpenCV BGR to RGB PIL Image
image_rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
pil_image = Image.fromarray(image_rgb)
# Run DETR detection
predictions = self.detr_pipe(pil_image)
# Filter by threshold and size, then add CLIP embeddings
detections = []
for pred in predictions:
score = pred.get("score", 0.0)
if score < self.detr_threshold:
continue
box = pred.get("box", {})
xmin = box.get("xmin", 0)
ymin = box.get("ymin", 0)
xmax = box.get("xmax", 0)
ymax = box.get("ymax", 0)
# Filter by minimum box size
box_width = xmax - xmin
box_height = ymax - ymin
if box_width < self.min_box_size or box_height < self.min_box_size:
continue
# Extract bounding box region
bbox_crop = pil_image.crop((xmin, ymin, xmax, ymax))
# Get embedding for this region
embedding = self._get_embedding_pil(bbox_crop)
detections.append(
{
"box": {"xmin": xmin, "ymin": ymin, "xmax": xmax, "ymax": ymax},
"score": score,
"embedding": embedding,
"label": pred.get("label", "logo"),
}
)
# Apply Non-Maximum Suppression to remove overlapping detections
detections = self._apply_nms(detections, self.nms_iou_threshold)
self.logger.debug(f"Detected {len(detections)} logos (threshold: {self.detr_threshold})")
return detections
def _apply_nms(self, predictions: List[Dict], iou_threshold: float) -> List[Dict]:
"""
Apply Non-Maximum Suppression to remove overlapping detections.
Args:
predictions: List of prediction dictionaries with 'box' and 'score'
iou_threshold: IoU threshold for considering boxes as overlapping
Returns:
Filtered list of predictions after NMS
"""
if len(predictions) == 0:
return []
# Extract boxes and scores
boxes = []
scores = []
for pred in predictions:
box = pred.get("box", {})
boxes.append([
box.get("xmin", 0),
box.get("ymin", 0),
box.get("xmax", 0),
box.get("ymax", 0)
])
scores.append(pred.get("score", 0.0))
# Convert to numpy arrays
boxes = np.array(boxes, dtype=np.float32)
scores = np.array(scores, dtype=np.float32)
# Sort by scores (descending)
sorted_indices = np.argsort(scores)[::-1]
keep_indices = []
while len(sorted_indices) > 0:
# Keep the box with highest score
current_idx = sorted_indices[0]
keep_indices.append(current_idx)
if len(sorted_indices) == 1:
break
# Calculate IoU with remaining boxes
current_box = boxes[current_idx]
remaining_boxes = boxes[sorted_indices[1:]]
ious = self._calculate_iou_batch(current_box, remaining_boxes)
# Keep only boxes with IoU below threshold
mask = ious < iou_threshold
sorted_indices = sorted_indices[1:][mask]
# Return predictions for kept indices
return [predictions[i] for i in keep_indices]
def _calculate_iou_batch(self, box: np.ndarray, boxes: np.ndarray) -> np.ndarray:
"""
Calculate IoU between one box and multiple boxes.
Args:
box: Single box [xmin, ymin, xmax, ymax]
boxes: Multiple boxes [[xmin, ymin, xmax, ymax], ...]
Returns:
Array of IoU values
"""
# Calculate intersection coordinates
x1 = np.maximum(box[0], boxes[:, 0])
y1 = np.maximum(box[1], boxes[:, 1])
x2 = np.minimum(box[2], boxes[:, 2])
y2 = np.minimum(box[3], boxes[:, 3])
# Calculate intersection area
intersection = np.maximum(0, x2 - x1) * np.maximum(0, y2 - y1)
# Calculate union area
box_area = (box[2] - box[0]) * (box[3] - box[1])
boxes_area = (boxes[:, 2] - boxes[:, 0]) * (boxes[:, 3] - boxes[:, 1])
union = box_area + boxes_area - intersection
# Calculate IoU
iou = intersection / (union + 1e-6) # Add small epsilon to avoid division by zero
return iou
def get_embedding(self, image: np.ndarray) -> torch.Tensor:
"""
Get embedding for a reference logo image.
This method is used to compute embeddings for reference logos
that will be compared against detected regions.
Args:
image: OpenCV image (BGR format, numpy array)
Returns:
Normalized feature embedding (torch.Tensor)
"""
# Convert OpenCV BGR to RGB PIL Image
image_rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
pil_image = Image.fromarray(image_rgb)
return self._get_embedding_pil(pil_image)
def _preprocess_image(self, pil_image: Image.Image, target_size: int = 224) -> Image.Image:
"""
Preprocess image based on the configured preprocessing mode.
Args:
pil_image: PIL Image (RGB format)
target_size: Target size for the square output (default 224 for CLIP)
Returns:
Preprocessed PIL Image
"""
if self.preprocess_mode == "default":
# Let the processor handle it (resize shortest edge + center crop)
return pil_image
width, height = pil_image.size
if self.preprocess_mode == "letterbox":
# Pad to square with black bars, preserving aspect ratio
max_dim = max(width, height)
# Create a black square canvas
new_image = Image.new("RGB", (max_dim, max_dim), (0, 0, 0))
# Paste the original image centered
paste_x = (max_dim - width) // 2
paste_y = (max_dim - height) // 2
new_image.paste(pil_image, (paste_x, paste_y))
# Resize to target size
return new_image.resize((target_size, target_size), Image.LANCZOS)
elif self.preprocess_mode == "stretch":
# Stretch to square (distorts aspect ratio)
return pil_image.resize((target_size, target_size), Image.LANCZOS)
else:
# Unknown mode, return original
return pil_image
def _get_embedding_pil(self, pil_image: Image.Image) -> torch.Tensor:
"""
Internal method to get embedding from PIL image.
Handles CLIP, fine-tuned CLIP, and DINOv2 model types.
Args:
pil_image: PIL Image (RGB format)
Returns:
Normalized feature embedding (torch.Tensor)
"""
# Apply preprocessing if configured
if self.preprocess_mode != "default":
pil_image = self._preprocess_image(pil_image)
# Process image through the embedding model
inputs = self.embedding_processor(images=pil_image, return_tensors="pt").to(self.device)
with torch.no_grad():
if self.model_type == "clip":
# CLIP has a dedicated method for image features
features = self.embedding_model.get_image_features(**inputs)
elif self.model_type == "clip_finetuned":
# Fine-tuned CLIP uses get_image_features or forward with pixel_values
features = self.embedding_model.get_image_features(**inputs)
else:
# DINOv2 and other transformers use the CLS token or pooled output
outputs = self.embedding_model(**inputs)
# Use the CLS token (first token) from last hidden state
if hasattr(outputs, 'pooler_output') and outputs.pooler_output is not None:
features = outputs.pooler_output
else:
# Use CLS token from last_hidden_state
features = outputs.last_hidden_state[:, 0, :]
# Normalize for cosine similarity (fine-tuned model already normalizes)
if self.model_type != "clip_finetuned":
features = F.normalize(features, dim=-1)
return features
def compare_embeddings(
self, embedding1: torch.Tensor, embedding2: torch.Tensor
) -> float:
"""
Compute cosine similarity between two CLIP embeddings.
Args:
embedding1: First CLIP embedding (torch.Tensor)
embedding2: Second CLIP embedding (torch.Tensor)
Returns:
Cosine similarity score (float, range: -1 to 1, typically 0 to 1)
"""
# Ensure tensors are on the same device
if embedding1.device != embedding2.device:
embedding2 = embedding2.to(embedding1.device)
# Compute cosine similarity
similarity = F.cosine_similarity(embedding1, embedding2, dim=-1)
# Return as Python float
return similarity.item()
def find_best_match(
self,
detected_embedding: torch.Tensor,
reference_embeddings: List[Tuple[str, torch.Tensor]],
similarity_threshold: float = 0.7,
) -> Optional[Tuple[str, float]]:
"""
Find the best matching reference logo for a detected embedding.
Args:
detected_embedding: CLIP embedding from detected logo region
reference_embeddings: List of (label, embedding) tuples for reference logos
similarity_threshold: Minimum similarity to consider a match (0-1)
Returns:
Tuple of (label, similarity) for best match, or None if no match above threshold
"""
if not reference_embeddings:
return None
best_similarity = -1.0
best_label = None
for label, ref_embedding in reference_embeddings:
similarity = self.compare_embeddings(detected_embedding, ref_embedding)
if similarity > best_similarity:
best_similarity = similarity
best_label = label
if best_similarity >= similarity_threshold:
return (best_label, best_similarity)
else:
return None
def find_all_matches(
self,
detected_embedding: torch.Tensor,
reference_embeddings: List[Tuple[str, torch.Tensor]],
similarity_threshold: float = 0.7,
) -> List[Tuple[str, float]]:
"""
Find all matching reference logos above the similarity threshold.
Unlike find_best_match, this returns ALL logos that have at least one
reference above threshold. Each unique logo is returned once with its
highest similarity score.
Args:
detected_embedding: CLIP embedding from detected logo region
reference_embeddings: List of (label, embedding) tuples for reference logos
similarity_threshold: Minimum similarity to consider a match (0-1)
Returns:
List of (label, similarity) tuples for all matches above threshold,
sorted by similarity descending. Each logo appears at most once.
"""
if not reference_embeddings:
return []
# Track best similarity for each logo
logo_best_sim: Dict[str, float] = {}
for label, ref_embedding in reference_embeddings:
similarity = self.compare_embeddings(detected_embedding, ref_embedding)
if similarity >= similarity_threshold:
if label not in logo_best_sim or similarity > logo_best_sim[label]:
logo_best_sim[label] = similarity
# Convert to list and sort by similarity descending
matches = [(label, sim) for label, sim in logo_best_sim.items()]
matches.sort(key=lambda x: x[1], reverse=True)
return matches
def find_best_match_multi_ref(
self,
detected_embedding: torch.Tensor,
reference_embeddings: Dict[str, List[torch.Tensor]],
similarity_threshold: float = 0.85,
min_matching_refs: int = 1,
use_mean_similarity: bool = True,
margin: float = 0.0,
) -> Optional[Tuple[str, float, int]]:
"""
Find the best matching reference logo using multiple reference embeddings per logo.
This method improves accuracy by using multiple reference images for each logo
and requiring consistency across references.
Args:
detected_embedding: CLIP embedding from detected logo region
reference_embeddings: Dict mapping logo name to list of embeddings
similarity_threshold: Minimum similarity to consider a match (0-1)
min_matching_refs: Minimum number of references that must match above threshold
use_mean_similarity: If True, use mean similarity across all refs; if False, use max
margin: Required margin between best and second-best logo scores (0-1)
Returns:
Tuple of (label, similarity, num_matching_refs) for best match,
or None if no match meets criteria
"""
if not reference_embeddings:
return None
# Calculate scores for all logos that meet the min_matching_refs requirement
logo_scores = []
for label, ref_embedding_list in reference_embeddings.items():
if not ref_embedding_list:
continue
# Calculate similarity to each reference embedding
similarities = []
for ref_embedding in ref_embedding_list:
sim = self.compare_embeddings(detected_embedding, ref_embedding)
similarities.append(sim)
# Count how many references match above threshold
num_matches = sum(1 for s in similarities if s >= similarity_threshold)
# Calculate aggregate score
if use_mean_similarity:
score = sum(similarities) / len(similarities)
else:
score = max(similarities)
# Only consider logos that meet the minimum matching refs requirement
if num_matches >= min_matching_refs:
logo_scores.append((label, score, num_matches))
if not logo_scores:
return None
# Sort by score descending
logo_scores.sort(key=lambda x: x[1], reverse=True)
best_label, best_score, best_num_matches = logo_scores[0]
# Check if best score meets threshold
if best_score < similarity_threshold:
return None
# Check margin against second-best logo (if exists)
if margin > 0 and len(logo_scores) > 1:
second_best_score = logo_scores[1][1]
if best_score - second_best_score < margin:
return None # Not confident enough
return (best_label, best_score, best_num_matches)
def find_best_match_with_margin(
self,
detected_embedding: torch.Tensor,
reference_embeddings: List[Tuple[str, torch.Tensor]],
similarity_threshold: float = 0.85,
margin: float = 0.05,
) -> Optional[Tuple[str, float]]:
"""
Find best match with a confidence margin over the second-best match.
This reduces false positives by requiring the best match to be
significantly better than alternatives.
Args:
detected_embedding: CLIP embedding from detected logo region
reference_embeddings: List of (label, embedding) tuples for reference logos
similarity_threshold: Minimum similarity to consider a match (0-1)
margin: Required margin between best and second-best match
Returns:
Tuple of (label, similarity) for best match, or None if no confident match
"""
if not reference_embeddings:
return None
# Calculate all similarities
similarities = []
for label, ref_embedding in reference_embeddings:
sim = self.compare_embeddings(detected_embedding, ref_embedding)
similarities.append((label, sim))
# Sort by similarity descending
similarities.sort(key=lambda x: x[1], reverse=True)
best_label, best_sim = similarities[0]
# Check if best is above threshold
if best_sim < similarity_threshold:
return None
# Check margin against second best (if exists)
if len(similarities) > 1:
second_best_sim = similarities[1][1]
if best_sim - second_best_sim < margin:
return None # Not confident enough
return (best_label, best_sim)
def detect_and_match(
self,
image: np.ndarray,
reference_embeddings: List[Tuple[str, torch.Tensor]],
similarity_threshold: float = 0.7,
) -> List[Dict[str, Any]]:
"""
Detect logos and match them against reference embeddings in one step.
This is a convenience method that combines detection and matching.
Args:
image: OpenCV image (BGR format, numpy array)
reference_embeddings: List of (label, embedding) tuples for reference logos
similarity_threshold: Minimum similarity to consider a match (0-1)
Returns:
List of matched detections, each containing:
- 'box': bounding box coordinates
- 'detr_score': DETR confidence score
- 'clip_similarity': CLIP similarity score
- 'label': matched reference logo label
"""
# Detect all logos
detections = self.detect(image)
# Match each detection against references
matched_detections = []
for detection in detections:
match_result = self.find_best_match(
detection["embedding"], reference_embeddings, similarity_threshold
)
if match_result is not None:
label, similarity = match_result
matched_detections.append(
{
"box": detection["box"],
"detr_score": detection["score"],
"clip_similarity": similarity,
"label": label,
}
)
self.logger.debug(
f"Matched {len(matched_detections)}/{len(detections)} detections "
f"(threshold: {similarity_threshold})"
)
return matched_detections