From 4b2fae258f120000b6aba1e9b848fefc66badff9 Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauldmccarthy@gmail.com>
Date: Tue, 23 Jun 2020 11:18:23 +0100
Subject: [PATCH] DOC: Note on fnirt deformation fields
---
fsl/transform/fnirt.py | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fsl/transform/fnirt.py b/fsl/transform/fnirt.py
index 2a2351a0e..4fa4051c8 100644
--- a/fsl/transform/fnirt.py
+++ b/fsl/transform/fnirt.py
@@ -82,6 +82,12 @@ the reference image, and may contain:
the source image coordinates which correspond to those reference image
coordinates.
+.. note:: FNIRT deformation field files give no indication as to whether they
+ contain relative displacements or absolute coordinates, so heuristics
+ must be used to infer what is stored in a a particular file. The
+ :func:`.nonlinear.detectDeformationType` function can be used to
+ determine whether a file contains relative displacements or absolute
+ coordinates.
If an initial linear registration was used as the starting point for FNIRT,
this is encoded into the displacements/coordinates themselves, so they can be
--
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