🤖 AI Summary
Existing geometric data augmentation methods often disrupt the topological connectivity between inner and outer boundaries of ring-shaped polygon annotations, leading to structural information loss. This work proposes a topology-preserving polygon augmentation strategy that first applies geometric transformations in mask space, then projects surviving vertices back into index space and reconstructs the original traversal order via a cyclic adjacency restoration algorithm. Designed specifically for ring-shaped polygons, this approach introduces the first mechanism explicitly tailored to preserve topological integrity during augmentation. It achieves near-perfect cyclic adjacency preservation (CAP) rates under both single and composite augmentation settings, effectively balancing computational efficiency with structural fidelity.
📝 Abstract
Geometric data augmentation is widely used in segmentation pipelines and typically assumes that polygon annotations represent simply connected regions. However, in structured domains such as architectural floorplan analysis, ring-type regions are often encoded as a single cyclic polygon chain connecting outer and inner boundaries. During augmentation, clipping operations may remove intermediate vertices and disrupt this cyclic connectivity, breaking the structural relationship between the boundaries. In this work, we introduce an order-preserving polygon augmentation strategy that performs transformations in mask space and then projects surviving vertices back into index-space to restore adjacency relations. This repair maintains the original traversal order of the polygon and preserves topological consistency with minimal computational overhead. Experiments demonstrate that the approach reliably restores connectivity, achieving near-perfect Cyclic Adjacency Preservation (CAP) across both single and compound augmentations.