The Neptune system allows unmanned entry and sensor data collection in
above-ground storage tanks (ASTs). The sensors are immersed in the pe
troleum product and uses video and ultrasonics to ascertain from the i
nside-out the state of corrosion of the floor and side-walls. This eli
minates the need to empty or clean the tanks and also avoids the requi
red human walk-through inspection, which results in a very sparse data
set. from which the tank's state must be statistically extrapolated.