Snapper: Accelerating bounding box annotation in object detection tasks with find-and-snap tooling

Object detection tasks are central to the development of datasets and algorithms in computer vision and machine learning. Despite its centrality, object detection remains tedious and time-consuming due to the inherent interactions that are often associated with drawing precise annotations. In this paper, we introduce Snapper, an interactive and intelligent annotation tool that intercepts bounding box annotations as they’re drawn and “snaps” them to the nearby object edges in real-time. Through a mixed-design user study with 18 full-time annotators, we compare Snapper’s annotation mode to alternative modes of annotation and find that Snapper enables participants to complete object detection tasks 39% more quickly without diminishing annotation quality. Further, we find that participants perceive Snapper as a tool that is interactively intuitive, trustworthy, and helpful. We conclude by discussing the implications of our findings as they relate to augmenting annotators’ conventions for drawing annotations in practice.