** Next:** Introduction

**Measuring Transformation Error by RMS Deviation**

FMRIB Technical Report TR99MJ1

**Mark Jenkinson**

Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB),

Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital,

Headley Way, Headington, Oxford, UK

### Abstract:

This report describes the RMS deviation measure used to calculate the
average difference between two affine transformations. The measure is
easy to calculate (a few simple matrix products and a trace) and gives
an estimate in real units (mm) of the difference in transformations.

Mark Jenkinson
2003-02-11