\chapter*{Introduction}
\addcontentsline{toc}{chapter}{Introduction}
Visualization plays important role in analyzing, exploring and presenting data. But what exactly is a visualization? There are many definitions. One says it is the use of computer-generated, interactive, visual representations of data to amplify cognition \cite{card1999readings}. Another says it is a transformation of symbolic into geometric \cite{McCormick1987vis}. From scientific point of view it is a relatively newly recognized field, although one may argue, that visualization is as old as humanity, or at least as old as paintings in the Chauvet Cave. Nevertheless, most definitions agree upon one thing -- the purpose of visualization is to provide a~user a better insight into data. 

Even in the short time that visualization has been around as a recognized scientific field, it has evolved immensely, no doubt driven by enormous quantities of new data that increase in volume every year. These data need to be processed and analyzed effectively, otherwise they may lose their value. However, visualizing large amounts of data is often challenging, especially for multivariate data spanning across several dimensions.

In my work I am going to explore the field of 3D facial data comparison and analysis. Facial analysis is used in many areas -- such as criminal identification, authorization software and plastic surgery as well as medical and anthropological research. Until recently, many of these areas worked only with 2D image representation. However, as technology evolves, 3D imaging becomes more and more common. New dimension means new data, but it also poses new challenges for visualization of these data. How to visualize more than one facial surface without facing occlusions or loosing track of data adherence? How to encode the measurements  and visualize them to best convey their meaning? How to easily identify correlations between data?

My aim in this work is to overcome some of these challenges in order to extend the visualization possibilities of FIDENTIS Analyst application, which is a part of interdisciplinary collaborative project FIDENTIS. The project is focused on analysis of 3D facial data and strives to provide a compact toolbox for this purposes. 

In the first chapter I am going to introduce the FIDENTIS project in closer detail. I will describe its aim and parts dedicated to comparison in order to analyze the needs of the application in terms of visualization. 

The second chapter is dedicated to research of related work in the field of visualization and visual analysis of 3D surfaces. I will examine several techniques in order to pick or design the best solution for my case of study. 

In third chapter I am going to present the chosen techniques and in fourth chapter I will describe their implementation. 

In the final fifth chapter I will present the results of my work and evaluate the contribution of my work based on the user study among scientist from the field of facial analysis.

