A Projector as a Novel Type of Motion Sensor
Motion sensors are useful for a large variety of applications including robot navigation, virtual reality, movie special effects, and 3D reconstruction. A camera is a cheap form of 6 DOF motion sensors, but automatic recovery of camera motion from images often fails in arbitrary environments. More robustness is obtained from installations using electromagnetic or ultrasound sensors but these are expensive, lack portability, and have a fixed-size workspace. Systems that involve instrumenting the environment with LEDs or distinctive visual markers also lack portability, and require significant calibration. This project describes a novel type of motion sensor that is cheap, portable, with relatively straightforward calibration, and the workspace can be arbitrarily large. It requires the presence of a planar surface for projection, and is most suitable for indoor use where the ceiling or sidewalls provide the required surfaces.
Background & Objective: A cheap reliable motion sensor has many applications. Current work involves a motion sensor attached to a camera, to support 3D reconstruction.
Technical Discussion: A moving projector projects a (moving) pattern onto a planar surface, and this is observed by a fixed camera placed at an arbitrary position in the environment. The observed pattern allows recovery of the position and orientation of the projector - the projector can thus be attached to any object of interest, to serve as a motion sensor. The minimum requirement for the projected pattern is that it has three distinct points, so the projection device can be cheap, and total cost with camera could be sub-$100. For an extended workspace, multiple fixed cameras are placed around the environment.
Technology Areas:
Graphics
Computer Vision
Modification Date: July 7, 2008