The Coronal Hole Automated Recognition and Monitoring (CHARM) code detects coronal holes in SOHO EIT and other EUV images.
It is written in SolarSoft IDL (www.lmsal.com/solarsoft).
For a description of the image segmentation algorithm, see Krista & Gallagher (2009) http://adsabs.harvard.edu/abs/2009SoPh..256...87K