cubic-phase plate, is inserted into the optical path. An image captured with this
modified microscope appears distorted. It can be modeled as a filtered image,
where the filter kernel is approximately invariant to defocus. A digital inverse filter
is applied to the captured image to produce the effect of extended DOF [19].
By contrast, software-based methods generally resort to digital image fusion
to generate a single composite image from a set of optical section images that
have been captured across a range of focal distances around the best in-focus
position. These optical section images are usually captured along the z-axis, with
a translation step Dz no larger than the DOF of the objective lens. Each image is
intended to contain some portions of