General Linear Cameras with Finite Aperture 



Published in EGSR 2007  
Abstract
A pinhole camera selects a twodimensional set of rays from the fourdimensional light field. Pinhole cameras are a type of general linear camera, defined as planar 2D slices of the 4D light field. Cameras with finite apertures can be considered as the summation of a collection of pinhole cameras. In the limit they evaluate a twodimensional integral of the fourdimensional light field. Hence a general linear camera with finite aperture factors the 4D light field into two integrated dimensions and two imaged dimensions. We present a simple framework for representing these slices and integral projections, based on certain eigenspaces in a twoplane parameterization of the light field. Our framework allows for easy analysis of focus and perspective, and it demonstrates their dual nature. Using our framework, we present analogous taxonomies of perspective and focus, placing within them the familiar perspective, orthographic, crossslit, and bilinear cameras; astigmatic and anastigmatic focus; and several other varieties of perspective and focus. 

Figure 1. This figure illustrates the set relationships between the various types of linear cameras on the left, and the various types of focus on the right. The number of degrees of freedom is indicated with color. Click on any thumbnail at the top or region in the venn diagram to see an example scene rendered with that type of camera. When viewing an image, use the left or right keys to scroll through the other images. If you wish to inspect multiple images side by side, you can drag an open one out of the way and open a second. Click an image a second time to close it.  
Paper
Adobe Acrobat PDF (5 MB) Slides from talk at EGSR 2007 Powerpoint Slides (3.5 MB) 