Edge Propagation KD-Trees: Computing Approximate Nearest Neighbor Fields

Propagation-assisted kd-tree is a state-of-the-art method for computing approximate nearest neighbor (ANN) fields. In this method, each query patch needs descending search in the kd-tree and propagation search in the nearby patches. We observed that the query patches in the edge region need descending search, while other query patches only need propagation search. This can be an opportunity to save plenty of search time. In this letter, we propose edge propagation kd-trees to quickly compute ANNs. Our method can distinguish between edge patches and propagation patches in choosing the proper search. Experiments on public data set VidPairs show that our search method is 2-3 times faster than the propagation-assisted kd-tree search method at nearly the same accuracy.