Assembling and processing of registration methods by using xml (e.g. itk-based registrations; see Examples)
Dynamic integration of new concepts via DLL
Separation of methods and data (for independent use)
Evaluation of registration methods (by given or newly defined criteria)
Parameter optimization of registration methods (by given or newly defined criteria)
Currently more the 90 filters/methods (around 50 from itk ) integrated
Possible extension of the listed features to other image processing tasks (e.g. segmentation)
Several tools for processing, evaluation and optimization of assembled setups (see Tools)
Implemented in ISO C++
Platform independent
Open source (under GPL)
Several tools for processing, evaluation and optimization of assembled setups (see Tools)

What f.r.e.e. cannot do:

f.r.e.e. offers no GUI driven image fusion application (like Philips Syntegra). It is possible to build such an application based on f.r.e.e.. Right now f.r.e.e. offers only basic tool to facilitate the framework established by f.r.e.e.
f.r.e.e. offers (right now) now applications explicitly designed for the user group clinicians. The first applications for clinical routine based on f.r.e.e. are in development right now.

Features by user groups

Developers:

Open system with the possibility to easily integrate new components/ideas
Testing of new component's functionality with arbitrarily data
Evaluation of quality and performance of new components (comparison, benchmarking)

Scientists:

Open system with the possibility to easily integrate new components/ideas
Flexible combination of concepts and components
Fast prototyping of new registration approaches by scripting in XML
Exchange and comparability of methods and test data (separation of method and data; see Generic setup and Adaptation item/Adaptation list
Evaluation of methods by different criteria (e.g. accuracy, precision, sensitivity, specificity, duration...; see freeEval)
Detailed logs of the method processing (XML; see Statistic)
Parameter optimization of methods (see freeSO)

Clinicians:

You can find a short characterization of the user groups in the design section.