  Robotic assistants in a home environment are expected to perform various
complex tasks for their users. One particularly challenging task is pouring
drinks into cups, which for successful completion, requires the detection and
tracking of the liquid level during a pour to determine when to stop. In this
paper, we present a novel approach to autonomous pouring that tracks the liquid
level using an RGB-D camera and adapts the rate of pouring based on the liquid
level feedback. We thoroughly evaluate our system on various types of liquids
and under different conditions, conducting over 250 pours with a PR2 robot. The
results demonstrate that our approach is able to pour liquids to a target
height with an accuracy of a few millimeters.
