Ablation Studies

Detailed analysis of model architecture and hyperparameter contributions to performance

YOLO Architecture Ablation

Backbone Network Analysis

Evaluation of different backbone architectures on object detection performance. Comparing CSPDarknet, ResNet, and EfficientNet backbones.

Backbone mAP@0.5 FPS Params
CSPDarknet53 44.3 42.2 11.2M
ResNet50 41.8 45.1 25.6M
EfficientNet-B3 43.9 38.7 12.0M
Key Finding: CSPDarknet53 provides the best accuracy-efficiency trade-off for autonomous driving applications.

Neck Architecture Impact

Analysis of Feature Pyramid Network (FPN) and Path Aggregation Network (PAN) configurations on multi-scale feature fusion.

Neck Type mAP@0.5 Small Objects Large Objects
FPN Only 42.1 28.3 58.7
PAN Only 43.5 31.2 59.8
FPN + PAN 44.3 33.1 60.2
Key Finding: Combined FPN and PAN architecture improves detection of both small and large objects.

Head Configuration Study

Comparison of detection head designs including anchor-based vs anchor-free approaches and different loss function combinations.

Head Type mAP@0.5 Training Time Complexity
Anchor-based 43.2 12h High
Anchor-free 44.3 8h Low
Hybrid 44.1 10h Medium
Key Finding: Anchor-free detection heads provide better accuracy with reduced complexity and training time.

Lane Detection Ablation

Edge Detection Methods

Comparison of different edge detection algorithms for lane boundary identification, including Canny, Sobel, and Laplacian operators.

Method Accuracy Processing Time Robustness
Canny Edge 85.2% 15.3ms 6.2/10
Sobel Edge 82.7% 12.1ms 5.8/10
Laplacian 79.3% 8.9ms 5.2/10

Hough Transform Parameters

Analysis of Hough transform parameter sensitivity including rho and theta resolution, minimum line length, and maximum gap threshold.

Parameter Set Accuracy False Positives Processing Time
Standard 85.2% 12.3% 15.3ms
Fine Resolution 87.1% 15.7% 28.9ms
Coarse Resolution 82.4% 8.9% 9.7ms

Data Augmentation Ablation

Data Augmentation Impact on Model Performance

Geometric Augmentations

Evaluation of geometric transformations including rotation, scaling, translation, and perspective changes on model robustness.

Augmentation mAP Improvement Training Time Effect
Rotation (±15°) +2.3% +15% Positive
Scale (0.8-1.2) +1.8% +12% Positive
Perspective +3.1% +20% Positive

Color Augmentations

Analysis of color space transformations including brightness, contrast, saturation, and hue adjustments for lighting robustness.

Augmentation mAP Improvement Low-light Gain Effect
Brightness (±20%) +1.2% +4.5% Positive
Contrast (±15%) +0.9% +3.2% Positive
Hue (±10°) +0.3% +0.8% Neutral

Loss Function Ablation

Classification Loss Analysis

Comparison of different classification loss functions including Cross-Entropy, Focal Loss, and Label Smoothing on imbalanced datasets.

Loss Function Overall mAP Rare Classes Common Classes
Cross-Entropy 44.3% 28.7% 52.1%
Focal Loss 45.8% 35.2% 51.9%
Label Smoothing 44.7% 31.4% 51.8%
Key Finding: Focal Loss significantly improves detection of rare classes while maintaining overall performance.

Regression Loss Comparison

Evaluation of bounding box regression losses including IoU-based losses (GIoU, DIoU, CIoU) for improved localization accuracy.

Loss Type Localization mAP IoU Threshold Convergence
L1 Loss 42.1% 0.65 Slow
GIoU Loss 44.3% 0.72 Fast
CIoU Loss 45.1% 0.75 Fast

Hyperparameter Sensitivity Analysis

Learning Rate Impact

Analysis of learning rate sensitivity on model convergence and final performance. Testing different learning rate schedules and warmup strategies.

Learning Rate Final mAP Convergence Epoch Stability
1e-4 43.2% 120 High
1e-3 44.3% 85 Medium
1e-2 41.8% 45 Low

Batch Size Analysis

Evaluation of batch size effects on training stability, memory usage, and final model performance across different hardware configurations.

Batch Size mAP Memory (GB) Training Time
8 43.8% 4.2 Long
16 44.3% 8.1 Medium
32 44.1% 15.7 Short
Summary: These ablation studies demonstrate that anchor-free detection heads, combined FPN+PAN architecture, Focal Loss for classification, and CIoU Loss for regression provide the optimal configuration for autonomous driving applications.