\chapter{Introduction}
\label{chap:introduction}
A 3D scene in computer graphics is often described by its geometry, materials, and light sources.
Rendering techniques, such as path tracing or rasterization, sample the scene, obtain the necessary visual information, and produce a novel view.
However, these methods can be performance-demanding and the 3D representation of the scene might not be easy to acquire.
To render a view of a scene, only a light-propagation model suffices.
This model, called the \textit{light field}, describes the incoming light for any point and direction in the scene.
Lightweight image-based rendering methods can be used to produce novel views.
Scenes can be captured by light field cameras, camera arrays, or a moving camera.
The captured light field consists of multiple views of the scene.
Synthetic or even real-life scenes can be easily captured and reconstructed.

The main advantage of light field, in comparison to standard photography, is the option of advanced editing in post-process.
Standard photos and videos are captured from one position and with one focus distance and aperture settings at a time.
Light field can be viewed from different angles or focused at different parts of the scene. 
A virtual camera motion in a 3D environment can be simulated based only on the input set of 2D images.
Such editing and viewing options are in this thesis grouped to the term \textit{light field rendering}.

Light fields are currently not widely used in industry.
One drawback is the sampling rate.
A discrete approximation of light field, in the form of 2D images, does not contain continuous information about the scene.
Artifacts appear in parts of the scene with missing information.
Another issue is that storing the images requires a lot of memory.
Also, to achieve a completely sharp novel image, the geometry of the scene needs to be estimated. 
Preprocessing of the data is not always possible in real-time applications.
Depth or geometric input data increase the memory requirements and might not always be available.
One inherent limitation of light field is the impossibility to use standard 3D operations, such as collision detection or physics simulation.
The methods proposed in this thesis aim to solve the issues related to quality and performance.

Based on the study of existing light field rendering methods, the central hypothesis of this thesis is stated.
According to the hypothesis, a novel light field rendering method can be proposed and implemented. 
The advantages of this method over the state of the art include a better visual quality of the result, less input data, and less memory and computational requirements.
The proposed method is described in this thesis and the hypothesis is experimentally proven.

Light field rendering can be utilized to produce an input for virtual reality headsets, 3D autostereoscopic displays, 3D tablets, or standard 2D screens with simulated 3D movement.
Part of this thesis explores the 3D displays and proposes methods for optimal retrieval and processing of the input light field data.
In summary, this thesis contains original proposals covering the whole light field workflow, from the capturing of the data, their compression, streaming to the GPU, rendering of the novel view, to the potential application in industry.