I searched the internet for some assistance in removing the digital noise using the GNU Image Manipulation Program (GIMP), and stumbled upon a well written post about how to remove digital noise. The technique makes use of the GREYCstoration plugin for the GIMP.
I use the GIMP on Kubuntu Linux, and wondered if there was already a package created for GREYCstoration.
$ apt-cache search greyc
gimp-plugin-registry - A repository of optional extensions for The GIMP
I found it! So I installed it:
$ sudo apt-get install gimp-plugin-registry
After restarting the GIMP, here are the results: