Simple parallel image sharpening exercise for training purposes

This is a simple program that uses smoothing and edge detection to sharpen up a fuzzy image. As written, it produces a Portable Grey Map (PGM) file "sharpened.pgm" from an input "fuzzy.pgm". The PGM files are a relatively standard text format for greyscale images which can be viewed using, for example, the "display" program from the ImageMagick suite. If your desktop machine doesn't have "display" then you can try converting the file on the HPC platform, e.g. to produce a JPEG file: "convert sharpened.pgm sharpened.jpg".

It is deliberately written to be very simple and easy to understand so it can be used as a teaching example. It uses a very simple parallelisation strategy, designed to illustrate Amdahl's law with a purely serial part (file IO) and a parallel part (embarrassingly parallel calculation). The program could easily be made orders of magnitude faster with some simple modifications. It is deliberately written in a very naive manner so that it runs for a measurable amount of time. Typical timings for the serial program will be around 5 seconds, with between 0.1 and 0.2 seconds for IO.