Here is a simple example of using FixerLabsFocusFixer which is an inexpensive
plugin for Adobe Photoshop. I recently came across this program while looking at some
other software for improving the focus of scanned photographs. However the other
software was part of a larger package of mathematical programs which cost $799.
Which was much more than I was willing to pay.
My understanding is that the package uses a concept called deconvolution in which
fourier transforms are used to reverse the blur introduced by an out of focus lens.
This first picture is what we are starting with. In this detail from a
scanned 4x5 large format
transparency, a maintenance truck in the distance is the only traffic on this
new highway which was still under construction. The picture is a little blurry.