Broad Area Colloquium For AI-Geometry-Graphics-Robotics-Vision
(CS 528)
Light field microscopy
Marc Levoy
Computer Science Department
Stanford University
November 13, 2006, 4:15PM
TCSeq 200
http://graphics.stanford.edu/ba-colloquium/
Abstract
The light field is a four-dimensional function representing radiance along rays
as a function of position and direction in space. By inserting a microlens
array into the optical train of a conventional microscope, light fields can be
captured of biological (or other) specimens in a single snapshot. We can then
employ light field rendering to generate perspective flyarounds, at least up to
the angular limit of rays we have captured, and we can use synthetic focusing
to generate a focal stack, a set of images each focused on a different plane.
Since microscopes are inherently orthographic devices, perspective flyarounds
represent a new way to look at microscopic specimens. Focal stacks are not
new, but manual techniques for capturing them are time-consuming and hence not
applicable to moving or light-sensitive specimens. Applying 3D deconvolution
to these focal stacks, we can produce a set of cross sections, which can be
visualized using volume rendering. Ours is the first technology (of which we
are aware) that can produce volumetric models from a single photograph.
In this talk, I will describe a prototype light field microscope and show
perspective views, focal stacks, and reconstructed volumes for a variety of
biological specimens. I will also survey some promising directions for this
technology. For example, by introducing a second microlens array and a video
projector, we can control the light field arriving at a specimen as well as the
light field leaving it. Potential applications of this idea include microscope
scatterometry - measuring reflectance as a function of incident and reflected
angle, and "designer illumination" - illuminating one part of a microscopic
object while avoiding illuminating another.