Passive tomography of turbulence strength

Abstract

Turbulence is studied extensively in remote sensing, astronomy, meteorology, aerodynamics and fluid dynamics. The strength of turbulence is a statistical measure of local variations in the turbulent medium. It influences engineering decisions made in these domains. Turbulence strength (TS) also affects safety of aircraft and tethered balloons, and reliability of free-space electromagnetic relays. We show that it is possible to estimate TS, without having to reconstruct instantaneous fluid flow fields. Instead, the TS field can be directly recovered, passively, using videos captured from different viewpoints. We formulate this as a linear tomography problem with a structure unique to turbulence fields. No tight synchronization between cameras is needed. Thus, realization is very simple to deploy using consumer-grade cameras. We experimentally demonstrate this both in a lab and in a large-scale uncontrolled complex outdoor environment, which includes industrial, rural and urban areas. © 2014 Springer International Publishing.