Update README.md

Author: oesteban

README.md

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 [![codecov](https://codecov.io/gh/poldracklab/nitransforms/branch/master/graph/badge.svg)](https://codecov.io/gh/poldracklab/nitransforms)
 
 A development repo for [nipy/nibabel#656](https://github.com/nipy/nibabel/pull/656)
+
+## About
+Spatial transforms formalize mappings between coordinates of objects in biomedical images.
+Transforms typically are the outcome of image registration methodologies, which estimate
+the alignment between two images.
+Image registration is a prominent task present in nearly all standard image processing
+and analysis pipelines.
+The proliferation of software implementations of image registration methodologies has
+resulted in a spread of data structures and file formats used to preserve and communicate
+transforms.
+This segregation of formats precludes the compatibility between tools and endangers the
+reproducibility of results.
+We propose a software tool capable of converting between formats and resampling images
+to apply transforms generated by the most popular neuroimaging packages and libraries
+(AFNI, FSL, FreeSurfer, ITK, and SPM).
+The proposed software is subject to continuous integration tests to check the
+compatibility with each supported tool after every change to the code base.
+Compatibility between software tools and imaging formats is a necessary bridge 
+to ensure the reproducibility of results and enable the optimization and evaluation
+of current image processing and analysis workflows.