From 7da76a78fe44fe2c3d3ceb83051cac70dac356fb Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauld.mccarthy@gmail.com>
Date: Tue, 28 Jun 2016 16:13:11 +0100
Subject: [PATCH] New imagewrapper function, collapseExpansions, which
combines/collapses equivalent expansions which pertain to adjacent
vectors/slices/volumes.
---
fsl/data/imagewrapper.py | 60 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/fsl/data/imagewrapper.py b/fsl/data/imagewrapper.py
index 7d0f21ea5..f04f33a4f 100644
--- a/fsl/data/imagewrapper.py
+++ b/fsl/data/imagewrapper.py
@@ -883,3 +883,63 @@ def calcExpansion(slices, coverage):
expansions.extend(volExpansions)
return volumes, expansions
+
+
+def collapseExpansions(expansions, numDims):
+ """Scans through the given list of expansions (each assumed to pertain
+ to a single 3D image), and combines any which cover the same
+ image area, and cover adjacent volumes.
+
+ :args expansions: A list of expansion slices - see :func:`calcExpansions`.
+
+ :args numDims: Number of dimensions covered by each expansion,
+ not including the volume dimension (i.e. 3 for a 4D
+ image).
+
+ :returns: A list of expansions, with equivalent expansions that cover
+ adjacent images collapsed down.
+
+ .. note:: For one expansion ``exp`` in the ``expansions`` list, this
+ function assumes that the range at ``exp[numDims]`` contains
+ the image to which ``exp`` pertains (i.e.
+ ``exp[numDims] == (vol, vol + 1)``).
+ """
+ if len(expansions) == 0:
+ return []
+
+ commonExpansions = collections.OrderedDict()
+ expansions = sorted(expansions)
+
+ for exp in expansions:
+
+ vol = exp[numDims][0]
+ exp = tuple(exp[:numDims])
+ commonExps = commonExpansions.get(exp, None)
+
+ if commonExps is None:
+ commonExps = []
+ commonExpansions[exp] = commonExps
+
+ for i, (vlo, vhi) in enumerate(commonExps):
+
+ if vol >= vlo and vol < vhi:
+ break
+
+ elif vol == vlo - 1:
+ commonExps[i] = vol, vhi
+ break
+ elif vol == vhi:
+ commonExps[i] = vlo, vol + 1
+ break
+
+ else:
+ commonExps.append((vol, vol + 1))
+
+ collapsed = []
+
+ for exp, volRanges in commonExpansions.items():
+ for vlo, vhi in volRanges:
+ newExp = list(exp) + [(vlo, vhi)]
+ collapsed.append(newExp)
+
+ return collapsed
--
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