Abstract:
Light field rendering is an image-based rendering method first explicitly described in 1996. The light field function determines the radiance, or colour, seen along any ray into or out of a scene. It is a function over a 4D space of directed lines. With some restrictions on the placement of the eyepoint, almost any view of the scene can be recreated by sampling the light field function for every ray that goes through the eyepoint and the scene. In practice, the light field function consists of discrete samples obtained either photographically using a calibrated camera setup, or from computer-generated imagery. Light field rendering is a purely image-based rendering technique. No geometric information about the scene is required or derived in the process.
Although potentially capable of creating photorealistic renderings quickly, light field rendering has seen little use in either the research community, or the wider graphics world. The reasons may be traced to a number of weaknesses and limitations in the method, which make its use impractical.
This thesis explores and improves upon several aspects of light field rendering, with the aim of making it a more practical means of image-based rendering. The main contributions are:
• Better interpolation using a focal distance for improved rendering quality.
• Incorporating depth information in the light field.
• A light field parameterisation which encompasses the entire light field scene within a single structure.
• Creation and rendering of compressed light fields using the standard MPEG video encoding scheme.
• Use of light fields as a scene element in combination with polygon rendering.
The most important contribution of this thesis is the use of light field rendering in combination with another rendering method, namely polygon rendering. A scene can be composed using both polygon objects and light fields. Light fields can intersect with other light fields or with polygonal objects, and still be rendered in a consistent manner from all view directions. This demonstrates, for the first time, that light fields can be used as part of a general rendering system in a practical manner.