  Real-world scene perception is typically studied in the laboratory using
static picture viewing with restrained head position. Consequently, the
transfer of results obtained in this paradigm to real-word scenarios has been
questioned. The advancement of mobile eye-trackers and the progress in image
processing, however, permit a more natural experimental setup that, at the same
time, maintains the high experimental control from the standard laboratory
setting. We investigated eye movements while participants were standing in
front of a projector screen and explored images under four specific task
instructions. Eye movements were recorded with a mobile eye-tracking device and
raw gaze data was transformed from head-centered into image-centered
coordinates. We observed differences between tasks in temporal and spatial
eye-movement parameters and found that the bias to fixate images near the
center differed between tasks. Our results demonstrate that current mobile
eye-tracking technology and a highly controlled design support the study of
fine-scaled task dependencies in an experimental setting that permits more
natural viewing behavior than the static picture viewing paradigm.
