Tracking air movement in rooms.

A measurement system is described to record the movement in a room of neutral density balloons or bubbles, and thus the movement of air in that room. It is based on photogrammetric analysis of coincident video recordings made from several view points. Under laboratory conditions, the system was found capable of measuring position to an accuracy of +/-3cm over a range of 8m, andof measuring 3-D velocities to better than +/-0.05 m/s. The system was usable under field conditions, and could be operated in an occupied building. The largest space tested was approximately 30x15x10m. In the course of this work, the applicability of the use of balloons and bubbles for recording air movement was also explored. Balloons were found suited to typical natural room movements, but were unsuited to use within jets; bubbles were more appropriate for those.