SRIANN: Sphere Ring Intersection for Approximate Nearest Neighbor Search in Videos

Abstract

In the field of approximate nearest neighbor (ANN) search, rare of the existing approaches are tailored for video applications. The Ring Intersection Approximate Nearest Neighbor (RIANN) is the first ANN search algorithm for videos. It achieves real-time by performing the ANN search on the sparse grid and interpolating others. For some applications, the dense ANN search is needed to ensure the searching accuracy. To achieve dense ANN search in real-time, we consider the parallel computing as a solution. However, the RIANN algorithm is not suitable for parallel computing as the algorithm itself suffers from bad thread coherency. In this paper, we propose the Sphere Ring Intersection Approximate Nearest Neighbor (SRIANN), which solves the problem of bad thread coherency and improves the accuracy of ANN search compared to the original RIANN method. The experimental results show that the proposed method is the only one able to perform dense ANN search for CIF videos in real-time.