\documentclass[a4paper,12pt,pdftex]{exam}

\newcommand{\ptitle}{Eye tracker}
\input{../header.tex}
\firstpagefooter{Supervisor: Lukas Sonnenberg}{phone:}%
{email: lukas.sonnenberg@uni-tuebingen.de}

\begin{document}

\input{../instructions.tex}

In this project you will analyze eye-tracking data (courtesy of Gregor
Hardiess, Cognitive Neuroscience, Uni-T\"ubingen). In this task
subjects were viewing biblical images while their eye movements were
recorded.

In the accompanying datasets you find a subject's eye tracking data when viewing two different images 
(\emph{Genesis\_VIII.png} and \emph{Genesis\_XXXIX.png}, files \verb+1_1.mat+ and \verb+1_2.mat+, respectively). The experiment consisted of different trials. Each trial started with a fixation period, followed by the important free eye-movement part.
Each \verb+mat+-file contains five variables: \verb+frame_index+, the \verb+gaze_x+  and \verb+gaze_y+ position (in pixel on the screen), a boolean vector \verb+eye_found+ telling whether the tracker could actually estimate the eye position, and a vector \verb+marker+. The \verb+marker+ is used to indicate sections in the data. 0 can be ignored, 1 marks the fixation period and 2 indicates the actual trial. 
The screen was 37.6\,cm wide and 30.1\,cm high and had a resolution of 1280\,x\,1024\,pixel. The distance between subject's eyes and the screen was 50\,cm.
The eyetracker recorded ey positions with 60\,Hz. The fixation point was shown at the center of the screen and can be used to compensate for possible offests in the \verb+gaze_x+ and \verb+gaze_y+ positions.

\begin{questions}
  \question Familiarize yourself with the data.
  \begin{parts}
    \part Cut the data into chunks belonging to the same period (fixation and free eye-movements).
    
    \part Detect problems in the data (e.g. the eye was not found) and correct the eye traces. Interpolate linearily in these sections.
    
  \end{parts}

  \question Characterize the eye movements statistically.
  \begin{parts} 
    \part Calculate the eye speed and/or accelerations.
    
    \part Create a 'heatmap' plot of the eye-positions.
    
    \part Detect fixation points in the "free movement" part of the data.
  \end{parts}

  \question Compare the subject's behavior when viewing the different scenes.
\end{questions}

\end{document}