Lightfield displays potentially offer a new form of video content providing greater immersion and a stronger sense ofpresence. Invented by Gabriel Lippman in 19081, lightfield displays can present natural 3D images that have motionparallax in both horizontal and vertical directions. Importantly, they also allow the viewer to focus at different depthswithin the image, which is not possible with stereoscopic displays. Ideally they require a large depth of field. The depthof field is the range of depths, perpendicular to the display, over which the full resolution of the display (at zero depth) ismaintained. To make the best use of lightfield displays we need to know the depth of field and how image resolutiondecreases outside this range. Prior literature provides an indication of the depth of field for displays with shallow depthsof field. Such calculations are based on the Nyquist limit for multidimensional (angular and spatial) sampling.Extrapolating this approach for larger depths of field indicates that an infinite number of elemental pixels would berequired to achieve an infinite depth of field. If true this would be a disappointing result. However, such calculations arebased on the physical lightfield and do not take account of the observer. Taking account of the observer indicates thatonly a finite number of elemental pixels are required to achieve an infinite depth of field. This paper presents formulas,and their derivation, for the depth of field of lightfield displays with a large depth of field.
展开▼
