  We are under the illusion that seeing is effortless, but frequently the
visual system is lazy and makes us believe that we understand something when in
fact we don't. Labeling a picture forces us to become aware of the difficulties
underlying scene understanding. Suddenly, the act of seeing is not effortless
anymore. We have to make an effort in order to understand parts of the picture
that we neglected at first glance.
  In this report, an expert image annotator relates her experience on
segmenting and labeling tens of thousands of images. During this process, the
notes she took try to highlight the difficulties encountered, the solutions
adopted, and the decisions made in order to get a consistent set of
annotations. Those annotations constitute the SUN database.
