Light field: Difference between revisions
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Small survey over light fields. Light fields are also known as integral images over 3D scenes. | Small survey over light fields. Light fields are also known as integral images over 3D scenes. | ||
Lightfields were originally published by Gortler ''et al.''<ref name="gortler1996lumigraph"></ref> and Levoy ''et al.''<ref name="levoy1996lightfield"></ref> | Lightfields were originally published by Gortler ''et al.''<ref name="gortler1996lumigraph"></ref> and Levoy ''et al.''<ref name="levoy1996lightfield"></ref> | ||
==Introduction== | ==Introduction== | ||
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For many scenes, we can assume the air is transparent so that the radiance is consistent along the ray. | For many scenes, we can assume the air is transparent so that the radiance is consistent along the ray. | ||
In these situations, light fields can be reduced to 4D functions defined only on rays in some enclosed scene. | In these situations, light fields can be reduced to 4D functions defined only on rays in some enclosed scene. | ||
You can create a 4D parameterization using a two plane parameterization, typically represented as <math>(s,t,u,v)</math> or a (plane, angle) parameterization to define each ray. | You can create a 4D parameterization using a two plane parameterization, typically represented as <math>(s,t,u,v)</math>, or a (plane, angle) parameterization to define each ray. | ||
==Representations== | ==Representations== | ||
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The easiest way to collect light field data is to simulate it from within a virtual environment using software. | The easiest way to collect light field data is to simulate it from within a virtual environment using software. | ||
Alternative ways to represent light fields is as a radiance field (see NeRF) or as a light field network. | |||
===Parameterizations=== | |||
;Two-plane parameterization | |||
In the two plane parameterization, one plane represents the camera position (u,v) also known as the angular resolution and the other plane represents the pixels (s,t) known as the spatial resolution. | |||
This is also known as ''light slab'' or ''lumigraph''. For 360 light fields, multiple light slabs are needed to represent different directions. A limitation of this method is that transitions between light slabs may not be smooth. | |||
;Spherical | |||
;Plucker | |||
==Aperture== | ==Aperture== | ||
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==Focus== | ==Focus== | ||
See [http://www.plenoptic.info/pages/refocusing.html http://www.plenoptic.info/pages/refocusing.html] | |||
==Glossery== | |||
* Spatial resolution - resolution of the image-plane in the two-plane parameterization (i.e. resolution of the sub-aperture image) (e.g. 512x512). | |||
* Angular resolution - resolution in the angular-plane in the two-plane parameterization (e.g. 5x5 if you have 25 cameras). | |||
* Sub-aperture images - individual image from a single viewpoint, a fraction of the aperture. | |||
* Epipolar plane image (EPI) - image where the y-axis is the u-axis in the angular plane and x-axis is x-axis in spatial plane, useful for visualizing disparity. | |||
* Microlens Array - A set of lens behind the main lens in [[Wikipedia: Light field camera | lightfield cameras]]. | |||
==Resources== | ==Resources== | ||
* [http://www.plenoptic.info/index.html http://www.plenoptic.info/index.html] | |||
** [http://www.plenoptic.info/pages/refocusing.html http://www.plenoptic.info/pages/refocusing.html] | |||
==References== | ==References== | ||