FRAT is no longer supported. It has been superseeded by the CALATK, available here http://www.calatk.org

FRAT provides c++ libraries and applications for performing fluid registration based operations on 2D and 3D images. The registration method is based on the large displacement diffeomorphic mapping (LDDM) registration method and implements discretized fluid registration. This registration method is then applied to time series analysis, cross-sectional atlas building, and longitudinal atlas building. The individual tool components are:

LDDM: Fluid registration between two images.
TimeSeries: Time series analysis of longitudinal data for a single subject.
AtlasBuilder: Cross-sectional atlas building for a population of images.
LongitudinalAtlasBuilder: Longitudinal atlas building for a population of subjects, each with a longitudinal data set.
FRATUtils: A collection of utility functions for working with volumes and time series files