Intersection Prediction from Single 360° Image via Deep Detection of Possible Direction of Travel

Movie-Map, an interactive first-person-view map that engages the user in a simulated walking experience, comprises short 360{\deg} video segments separated by traffic intersections that are seamlessly connected according to the viewer's direction of travel. However, in wide urban-scale areas with numerous intersecting roads, manual intersection segmentation requires significant human effort. Therefore, automatic identification of intersections from 360{\deg} videos is an important problem for scaling up Movie-Map. In this paper, we propose a novel method that identifies an intersection from individual frames in 360{\deg} videos. Instead of formulating the intersection identification as a standard binary classification task with a 360{\deg} image as input, we identify an intersection based on the number of the possible directions of travel (PDoT) in perspective images projected in eight directions from a single 360{\deg} image detected by the neural network for handling various types of intersections. We constructed a large-scale 360{\deg} Image Intersection Identification (iii360) dataset for training and evaluation where 360{\deg} videos were collected from various areas such as school campus, downtown, suburb, and china town and demonstrate that our PDoT-based method achieves 88\% accuracy, which is significantly better than that achieved by the direct naive binary classification based method. The source codes and a partial dataset will be shared in the community after the paper is published.