Changes

=== Choosing a pinhole ===

=== Choosing a pinhole ===

It is crucial that any spherical aberration are removed by way of pinhole.  The laser spot is passed through a pinhole, which acts to expand the beam. This expansion creates a patter known as an [http://en.wikipedia.org/wiki/Airy_disk Airy pattern].

It is crucial that any spherical aberration are removed by way of pinhole.  The laser spot is passed through a pinhole, which acts to expand the beam. This expansion creates a patter known as an [http://en.wikipedia.org/wiki/Airy_disk Airy pattern]. To correctly remove the spherical aberrations, the beam must be expanded such that the only the first ring is sent through the second lens, and the rest is blocked off.  To determine the proper pinhole size for the design, [[Huygens Principle for a Planar Source|the following analysis was performed]].

 

* [[Huygens Principle for a Planar Source|Determining the angle of the diffraction minimum for a circular aperture]]

== Camera Calibration ==

== Camera Calibration ==