Quantum GIS also offer some sort of image segmentation and classification. As you know QGIS is freely available. For your ready reference, please have a look an example;

http://faunaliagis.wordpress.com/2013/08/15/detecting-tree-canopies-with-unsupervised-classification-in-sextante/

eCognition is best for object oriented classification for remote sensing imagery. eCognition allows integration of data from different sensors and with different

resolutions .The software works with objects, therefore the resolution has direct impact on the object creation. Though it is proprietary software , trial version is available as open source.

(http://www.ecognition.com/products/trialsoftware).

Thanks Philipp. Thats a great information.

Strongly agree with Richard and is the reason why i would go about opensource development. More than direct use, it is the insights and value additions that keep the research alive.

Thanks Richard