EHTracker - Fine-Grained Satellite Tracking

EHTracker: Towards Fine-Grained Localization for Satellite Video Target Tracking
J Yang, Y Liu, Y Liu, Z Wang, J Li, G Zhou, W Wang, Y Hu
Published in IEEE JSTARS, December 2024
DOI

Project Overview

Problem: Need for Fine-Grained Localization

Satellite video analysis requires precise target localization:

• High GSD (Ground Sampling Distance): Each pixel covers large ground area
• Small localization errors translate to significant ground distance
• Applications require precision: Traffic analysis, motion estimation, behavior understanding

Traditional trackers provide bounding boxes that are too coarse for detailed analysis.

Solution: Edge-Aware Hierarchical Tracker

EHTracker achieves fine-grained localization through:

1. Edge-aware feature extraction for precise boundaries
2. Hierarchical matching for progressive refinement
3. Geometric constraints from satellite imaging model

Key Innovations

1. Edge-Aware Feature Learning

Edge Detection Module:

• Sobel-based edge extraction
• Learnable edge enhancement
• Edge-guided feature weighting

Benefits:

• Precise boundary localization
• Shape preservation
• Better separation from background

2. Hierarchical Localization

Three-stage refinement:

1. Global search: Find target neighborhood
2. Local refinement: Improve position accuracy
3. Edge-based fine-tuning: Sub-pixel localization

3. Geometric Constraint Integration

Satellite-specific priors:

• Camera model constraints
• Ground plane assumptions
• Motion smoothness

Method

Architecture

class EHTracker:
    def track(self, frame, template):
        # Edge-aware features
        edge_features = self.edge_extractor(frame)
        
        # Hierarchical matching
        coarse_loc = self.global_match(edge_features, template)
        medium_loc = self.local_refinement(coarse_loc)
        fine_loc = self.edge_finetuning(medium_loc)
        
        return fine_loc

Results

Fine-grained localization accuracy:

• Sub-pixel precision achieved
• Outperforms coarse trackers significantly
• Maintains real-time performance

Applications:

• Vehicle trajectory analysis
• Speed estimation
• Behavior understanding

Citation

@article{yang2024ehtracker,
  title={EHTracker: Towards Fine-Grained Localization for Satellite Video Target Tracking},
  author={Yang, J and Liu, Y and Liu, Y and Wang, Z and Li, J and Zhou, G and Wang, W and Hu, Y},
  journal={IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year={2024},
  publisher={IEEE}
}