ENH:new preprocess interfaces in dipy (Denoise, Resample)

Author: oesteban

CHANGES

@@ -1,6 +1,7 @@
 Next Release
 ============
 
+* ENH: New dipy interfaces: Denoise, Resample
 * ENH: New Freesurfer interface: MRIPretess
 * ENH: New miscelaneous interface: AddCSVRow
 * ENH: FUGUE interface has been refactored to use the name_template system, 3 examples 

nipype/interfaces/dipy/__init__.py

@@ -1,2 +1,3 @@
 from .tracks import TrackDensityMap
 from .tensors import TensorMode
+from .preprocess import Resample, Denoise

nipype/interfaces/dipy/preprocess.py

@@ -0,0 +1,208 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# @Author: oesteban
+# @Date:   2014-09-01 10:33:35
+# @Last Modified by:   oesteban
+# @Last Modified time: 2014-09-01 11:27:55
+from nipype.interfaces.base import (traits, TraitedSpec, BaseInterface,
+                                    File, isdefined)
+from nipype.utils.filemanip import split_filename
+import os.path as op
+import nibabel as nb
+import numpy as np
+from nipype.utils.misc import package_check
+import warnings
+from ... import logging
+iflogger = logging.getLogger('interface')
+
+have_dipy = True
+try:
+    package_check('dipy', version='0.6.0')
+except Exception, e:
+    have_dipy = False
+else:
+    from dipy.align.aniso2iso import resample
+    from dipy.core.gradients import GradientTable
+    from dipy.denoise.nlmeans import nlmeans
+
+
+class ResampleInputSpec(TraitedSpec):
+    in_file = File(exists=True, mandatory=True,
+                   desc='The input 4D diffusion-weighted image file')
+    vox_size = traits.Tuple(traits.Float, traits.Float, traits.Float, desc=('specify the new '
+                            'voxel zooms. If no vox_size is set, then isotropic regridding will '
+                            'be performed, with spacing equal to the smallest current zoom.'))
+    interp = traits.Int(1, mandatory=True, usedefault=True, desc=('order of the interpolator'
+                        '(0 = nearest, 1 = linear, etc.'))
+
+
+class ResampleOutputSpec(TraitedSpec):
+    out_file = File(exists=True)
+
+
+class Resample(BaseInterface):
+    """
+    An interface to reslicing diffusion datasets.
+    See http://nipy.org/dipy/examples_built/reslice_datasets.html#example-reslice-datasets.
+
+    Example
+    -------
+
+    >>> import nipype.interfaces.dipy as dipy
+    >>> reslice = dipy.Resample()
+    >>> reslice.inputs.in_file = 'diffusion.nii'
+    >>> reslice.run() # doctest: +SKIP
+    """
+    input_spec = ResampleInputSpec
+    output_spec = ResampleOutputSpec
+
+    def _run_interface(self, runtime):
+        order = self.inputs.interp
+        vox_size = None
+
+        if isdefined(self.inputs.vox_size):
+            vox_size = self.inputs.vox_size
+
+        out_file = op.abspath(self._gen_outfilename())
+        resample_proxy(self.inputs.in_file, order=order,
+                       new_zooms=vox_size, out_file=out_file)
+
+        iflogger.info('Resliced image saved as {i}'.format(i=out_file))
+        return runtime
+
+    def _list_outputs(self):
+        outputs = self._outputs().get()
+        outputs['out_file'] = op.abspath(self._gen_outfilename())
+        return outputs
+
+    def _gen_outfilename(self):
+        fname, fext = op.splitext(op.basename(self.inputs.in_file))
+        if fext == '.gz':
+            fname, fext2 = op.splitext(fname)
+            fext = fext2 + fext
+        return op.abspath('%s_reslice%s' % (fname, fext))
+
+
+class DenoiseInputSpec(TraitedSpec):
+    in_file = File(exists=True, mandatory=True,
+                   desc='The input 4D diffusion-weighted image file')
+    in_mask = File(exists=True, desc='brain mask')
+    noise_model = traits.Enum('rician', 'gaussian', mandatory=True, usedefault=True,
+                              desc=('noise distribution model'))
+
+
+class DenoiseOutputSpec(TraitedSpec):
+    out_file = File(exists=True)
+
+
+class Denoise(BaseInterface):
+    """
+    An interface to denoising diffusion datasets [Coupe2008]_.
+    See http://nipy.org/dipy/examples_built/denoise_nlmeans.html#example-denoise-nlmeans.
+
+    .. [Coupe2008] P. Coupe, P. Yger, S. Prima, P. Hellier, C. Kervrann, C. Barillot,
+      `An Optimized Blockwise Non Local Means Denoising Filter for 3D Magnetic Resonance Images
+      <http://dx.doi.org/10.1109%2FTMI.2007.906087>`_,
+      IEEE Transactions on Medical Imaging, 27(4):425-441, 2008.
+
+    Example
+    -------
+
+    >>> import nipype.interfaces.dipy as dipy
+    >>> denoise = dipy.Denoise()
+    >>> denoise.inputs.in_file = 'diffusion.nii'
+    >>> denoise.run() # doctest: +SKIP
+    """
+    input_spec = DenoiseInputSpec
+    output_spec = DenoiseOutputSpec
+
+    def _run_interface(self, runtime):
+        out_file = op.abspath(self._gen_outfilename())
+
+        mask = None
+        if isdefined(self.inputs.in_mask):
+            mask = nb.load(self.inputs.in_mask).get_data()
+
+        nlmeans_proxy(self.inputs.in_file, in_mask=mask,
+                      rician=(self.inputs.noise_model=='rician'),
+                      out_file=out_file)
+        iflogger.info('Denoised image saved as {i}'.format(i=out_file))
+        return runtime
+
+    def _list_outputs(self):
+        outputs = self._outputs().get()
+        outputs['out_file'] = op.abspath(self._gen_outfilename())
+        return outputs
+
+    def _gen_outfilename(self):
+        fname, fext = op.splitext(op.basename(self.inputs.in_file))
+        if fext == '.gz':
+            fname, fext2 = op.splitext(fname)
+            fext = fext2 + fext
+        return op.abspath('%s_denoise%s' % (fname, fext))
+
+def resample_proxy(in_file, order=3, new_zooms=None, out_file=None):
+    """
+    Performs regridding of an image to set isotropic voxel sizes using dipy.
+    """
+
+    if out_file is None:
+        fname, fext = op.splitext(op.basename(in_file))
+        if fext == '.gz':
+            fname, fext2 = op.splitext(fname)
+            fext = fext2 + fext
+        out_file = op.abspath('./%s_reslice%s' % (fname, fext))
+
+    img = nb.load(in_file)
+    hdr = img.get_header().copy()
+    data = img.get_data().astype(np.float32)
+    affine = img.get_affine()
+    im_zooms = hdr.get_zooms()[:3]
+
+    if new_zooms is None:
+        minzoom = np.array(im_zooms).min()
+        new_zooms = tuple(np.ones((3,)) * minzoom)
+
+    if np.all(im_zooms == new_zooms):
+        return in_file
+
+    data2, affine2 = resample(data, affine, im_zooms, new_zooms, order=order)
+    tmp_zooms = np.array(hdr.get_zooms())
+    tmp_zooms[:3] = new_zooms[0]
+    hdr.set_zooms(tuple(tmp_zooms))
+    hdr.set_data_shape(data2.shape)
+    hdr.set_xyzt_units('mm')
+    nb.Nifti1Image(data2.astype(hdr.get_data_dtype()),
+                   affine2, hdr).to_filename(out_file)
+    return out_file, new_zooms
+
+
+def nlmeans_proxy(in_file, in_mask=None, rician=True, out_file=None):
+    """
+    Uses non-local means to denoise 4D datasets
+    """
+
+    if out_file is None:
+        fname, fext = op.splitext(op.basename(in_file))
+        if fext == '.gz':
+            fname, fext2 = op.splitext(fname)
+            fext = fext2 + fext
+        out_file = op.abspath('./%s_denoise%s' % (fname, fext))
+
+    img = nb.load(in_file)
+    hdr = img.get_header()
+    data = img.get_data()
+    aff = img.get_affine()
+
+    if in_mask is None:
+        mask = data[..., 0] > 80
+    else:
+        mask = in_mask > 0
+
+    sigma = np.std(data[~mask])
+    den = nlmeans(data, sigma=sigma, mask=mask)
+
+    nb.Nifti1Image(den.astype(hdr.get_data_dtype()), aff,
+                   hdr).to_filename(out_file)
+    return out_file
+

nipype/interfaces/dipy/tests/test_auto_Denoise.py

@@ -0,0 +1,27 @@
+# AUTO-GENERATED by tools/checkspecs.py - DO NOT EDIT
+from nipype.testing import assert_equal
+from nipype.interfaces.dipy.preprocess import Denoise
+
+def test_Denoise_inputs():
+    input_map = dict(in_file=dict(mandatory=True,
+    ),
+    in_mask=dict(),
+    noise_model=dict(mandatory=True,
+    usedefault=True,
+    ),
+    )
+    inputs = Denoise.input_spec()
+
+    for key, metadata in input_map.items():
+        for metakey, value in metadata.items():
+            yield assert_equal, getattr(inputs.traits()[key], metakey), value
+
+def test_Denoise_outputs():
+    output_map = dict(out_file=dict(),
+    )
+    outputs = Denoise.output_spec()
+
+    for key, metadata in output_map.items():
+        for metakey, value in metadata.items():
+            yield assert_equal, getattr(outputs.traits()[key], metakey), value
+

nipype/interfaces/dipy/tests/test_auto_Resample.py

@@ -0,0 +1,27 @@
+# AUTO-GENERATED by tools/checkspecs.py - DO NOT EDIT
+from nipype.testing import assert_equal
+from nipype.interfaces.dipy.preprocess import Resample
+
+def test_Resample_inputs():
+    input_map = dict(in_file=dict(mandatory=True,
+    ),
+    interp=dict(mandatory=True,
+    usedefault=True,
+    ),
+    vox_size=dict(),
+    )
+    inputs = Resample.input_spec()
+
+    for key, metadata in input_map.items():
+        for metakey, value in metadata.items():
+            yield assert_equal, getattr(inputs.traits()[key], metakey), value
+
+def test_Resample_outputs():
+    output_map = dict(out_file=dict(),
+    )
+    outputs = Resample.output_spec()
+
+    for key, metadata in output_map.items():
+        for metakey, value in metadata.items():
+            yield assert_equal, getattr(outputs.traits()[key], metakey), value
+