human-activity-backend / src /binary_model.py
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"""
Binary Classification Models for Individual Action Mastery
This creates optimized binary classifiers for single actions:
- Much simpler than 101-class classification
- Expected: 95%+ accuracy in 1-2 hours
- Foundation for category-building system
"""
import torch
import torch.nn as nn
from torchvision import models
class BinaryActionClassifier(nn.Module):
"""
Binary Action Classifier: [Target Action] vs [All Others]
Key advantages for Individual Action Mastery:
1. Only 2 classes β†’ much easier to learn
2. More focused feature extraction
3. Higher accuracy per action
4. Faster training time
"""
def __init__(self, pretrained=True, dropout=0.5):
super(BinaryActionClassifier, self).__init__()
# Use R3D-18 as backbone (same as your original model)
self.backbone = models.video.r3d_18(pretrained=pretrained)
# Replace final layer with binary classifier
# Original: 512 β†’ 101 classes
# New: 512 β†’ 2 classes (target vs others)
in_features = self.backbone.fc.in_features # Should be 512
self.backbone.fc = nn.Sequential(
nn.Dropout(dropout),
nn.Linear(in_features, 2) # Binary classification
)
print(f"πŸ”§ Binary classifier created: {in_features} β†’ 2 classes")
def forward(self, x):
return self.backbone(x)
class EnhancedBinaryClassifier(nn.Module):
"""
Enhanced binary classifier with additional regularization
For even higher accuracy on individual actions
"""
def __init__(self, pretrained=True, dropout=0.5, hidden_dim=256):
super(EnhancedBinaryClassifier, self).__init__()
# Use R3D-18 backbone
self.backbone = models.video.r3d_18(pretrained=pretrained)
# Remove the original FC layer
in_features = self.backbone.fc.in_features
self.backbone.fc = nn.Identity() # Remove final layer
# Add enhanced classification head
self.classifier = nn.Sequential(
nn.Dropout(dropout),
nn.Linear(in_features, hidden_dim),
nn.ReLU(),
nn.BatchNorm1d(hidden_dim),
nn.Dropout(dropout / 2),
nn.Linear(hidden_dim, 2)
)
print(f"πŸ”§ Enhanced binary classifier: {in_features} β†’ {hidden_dim} β†’ 2 classes")
def forward(self, x):
features = self.backbone(x)
return self.classifier(features)
def get_binary_model(model_type="simple", **kwargs):
"""
Factory function to create binary classification models
Args:
model_type: "simple" or "enhanced"
**kwargs: Additional arguments for the model
Returns:
Binary classification model (2 classes)
"""
if model_type == "simple":
model = BinaryActionClassifier(**kwargs)
print("🎯 Created Simple Binary Classifier")
elif model_type == "enhanced":
model = EnhancedBinaryClassifier(**kwargs)
print("🎯 Created Enhanced Binary Classifier")
else:
raise ValueError(f"Unknown model_type: {model_type}")
# Count parameters
total_params = sum(p.numel() for p in model.parameters())
trainable_params = sum(p.numel() for p in model.parameters() if p.requires_grad)
print(f"πŸ“Š Model parameters: {total_params:,} total, {trainable_params:,} trainable")
return model
class BinaryModelTrainer:
"""
Specialized trainer for binary action classification
Optimized for high accuracy on individual actions
"""
def __init__(self, model, device, class_weights=None):
self.model = model
self.device = device
# Use weighted cross-entropy for class imbalance
if class_weights is not None:
class_weights = class_weights.to(device)
self.criterion = nn.CrossEntropyLoss(weight=class_weights)
print(f"βš–οΈ Using weighted loss with weights: {class_weights}")
else:
self.criterion = nn.CrossEntropyLoss()
print("πŸ“ Using standard cross-entropy loss")
# Optimizer with different learning rates for backbone vs classifier
self.optimizer = self._create_optimizer()
def _create_optimizer(self):
"""Create optimizer with differential learning rates"""
# Lower learning rate for pretrained backbone
backbone_params = []
classifier_params = []
for name, param in self.model.named_parameters():
if 'classifier' in name or 'fc' in name:
classifier_params.append(param)
else:
backbone_params.append(param)
optimizer = torch.optim.Adam([
{'params': backbone_params, 'lr': 1e-4}, # Lower LR for pretrained
{'params': classifier_params, 'lr': 1e-3} # Higher LR for new layers
])
print("πŸŽ“ Created differential learning rate optimizer")
return optimizer
def train_epoch(self, train_loader):
"""Train for one epoch"""
self.model.train()
total_loss = 0
correct = 0
total = 0
for clips, labels in train_loader:
clips, labels = clips.to(self.device), labels.to(self.device)
self.optimizer.zero_grad()
outputs = self.model(clips)
loss = self.criterion(outputs, labels)
loss.backward()
self.optimizer.step()
total_loss += loss.item()
_, predicted = outputs.max(1)
total += labels.size(0)
correct += predicted.eq(labels).sum().item()
avg_loss = total_loss / len(train_loader)
accuracy = 100. * correct / total
return avg_loss, accuracy
def validate_epoch(self, test_loader):
"""Validate for one epoch"""
self.model.eval()
total_loss = 0
correct = 0
total = 0
# For detailed binary classification metrics
true_positives = 0
false_positives = 0
false_negatives = 0
true_negatives = 0
with torch.no_grad():
for clips, labels in test_loader:
clips, labels = clips.to(self.device), labels.to(self.device)
outputs = self.model(clips)
loss = self.criterion(outputs, labels)
total_loss += loss.item()
_, predicted = outputs.max(1)
total += labels.size(0)
correct += predicted.eq(labels).sum().item()
# Binary classification metrics
for pred, true in zip(predicted, labels):
if pred == 1 and true == 1:
true_positives += 1
elif pred == 1 and true == 0:
false_positives += 1
elif pred == 0 and true == 1:
false_negatives += 1
else:
true_negatives += 1
avg_loss = total_loss / len(test_loader)
accuracy = 100. * correct / total
# Calculate precision, recall, F1
precision = true_positives / (true_positives + false_positives) if (true_positives + false_positives) > 0 else 0
recall = true_positives / (true_positives + false_negatives) if (true_positives + false_negatives) > 0 else 0
f1_score = 2 * (precision * recall) / (precision + recall) if (precision + recall) > 0 else 0
return avg_loss, accuracy, precision, recall, f1_score
def save_binary_model(model, target_action, save_dir="C:\\ASH_PROJECT\\outputs\\binary_models"):
"""Save trained binary model with descriptive name"""
import os
os.makedirs(save_dir, exist_ok=True)
model_path = os.path.join(save_dir, f"{target_action.lower()}_binary_model.pth")
torch.save(model.state_dict(), model_path)
print(f"πŸ’Ύ Binary model saved: {model_path}")
return model_path
def load_binary_model(target_action, model_type="simple", save_dir="C:\\ASH_PROJECT\\outputs\\binary_models"):
"""Load trained binary model"""
import os
model_path = os.path.join(save_dir, f"{target_action.lower()}_binary_model.pth")
if not os.path.exists(model_path):
raise FileNotFoundError(f"Model not found: {model_path}")
model = get_binary_model(model_type)
model.load_state_dict(torch.load(model_path))
print(f"πŸ“ Binary model loaded: {model_path}")
return model
if __name__ == "__main__":
# Test binary model creation
print("πŸ§ͺ Testing Binary Model Creation...")
# Test simple model
simple_model = get_binary_model("simple")
# Test enhanced model
enhanced_model = get_binary_model("enhanced", hidden_dim=512, dropout=0.3)
# Test with dummy input
dummy_input = torch.randn(2, 3, 16, 112, 112) # [batch, channels, frames, height, width]
print("\nπŸ” Testing forward pass...")
with torch.no_grad():
simple_output = simple_model(dummy_input)
enhanced_output = enhanced_model(dummy_input)
print(f"Simple model output: {simple_output.shape}")
print(f"Enhanced model output: {enhanced_output.shape}")
# Should be [batch_size, 2] for binary classification
assert simple_output.shape == (2, 2), f"Expected (2, 2), got {simple_output.shape}"
assert enhanced_output.shape == (2, 2), f"Expected (2, 2), got {enhanced_output.shape}"
print("βœ… Binary model test completed!")
print("🎯 Ready for basketball binary classification training!")