Cameras as displacement transducers - Another approach to motion measurement in two or three dimensions

摘要

Most engineers understand the idea that an isolated image can be scaled to produce meaningful displacements. Rulers are often placed in an image to provide a simple basis for scaling objects in the image. This basic concept is not difficult to explain, even to people with no formal training in engineering; however, an appreciation of a fully automated tracking system that can acquire accurate and precise trajectory data for many points, in two or three dimensions, is a substantial leap from a simple scale. In this brief article, we will set aside the more traditional role of cameras (that is, as devices for recording the state of an "object-space" in a qualitative fashion), and consider their role as data capture devices - or displacement transducers.