Passed
Push — master ( ac682b...5f1f08 )
by Fernando
01:51 queued 46s
created

torchio.data.image.Image.__init__()   C

Complexity

Conditions 10

Size

Total Lines 48
Code Lines 37

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 10
eloc 37
nop 9
dl 0
loc 48
rs 5.9999
c 0
b 0
f 0

How to fix   Complexity    Many Parameters   

Complexity

Complex classes like torchio.data.image.Image.__init__() often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.

Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.

Many Parameters

Methods with many parameters are not only hard to understand, but their parameters also often become inconsistent when you need more, or different data.

There are several approaches to avoid long parameter lists:

1
import warnings
2
from pathlib import Path
3
from typing import Any, Dict, Tuple, Optional
4
5
import torch
6
import humanize
7
import numpy as np
8
import nibabel as nib
9
import SimpleITK as sitk
10
11
from ..utils import (
12
    nib_to_sitk,
13
    get_rotation_and_spacing_from_affine,
14
    get_stem,
15
    ensure_4d,
16
)
17
from ..torchio import (
18
    TypeData,
19
    TypePath,
20
    TypeTripletInt,
21
    TypeTripletFloat,
22
    DATA,
23
    TYPE,
24
    AFFINE,
25
    PATH,
26
    STEM,
27
    INTENSITY,
28
    LABEL,
29
)
30
from .io import read_image, write_image
31
32
33
PROTECTED_KEYS = DATA, AFFINE, TYPE, PATH, STEM
34
35
36
class Image(dict):
37
    r"""TorchIO image.
38
39
    For information about medical image orientation, check out `NiBabel docs`_,
40
    the `3D Slicer wiki`_, `Graham Wideman's website`_, `FSL docs`_ or
41
    `SimpleITK docs`_.
42
43
    Args:
44
        path: Path to a file that can be read by
45
            :mod:`SimpleITK` or :mod:`nibabel`, or to a directory containing
46
            DICOM files. If :py:attr:`tensor` is given, the data in
47
            :py:attr:`path` will not be read. The data is expected to be 2D or
48
            3D, and may have multiple channels (see :attr:`num_spatial_dims` and
49
            :attr:`channels_last`).
50
        type: Type of image, such as :attr:`torchio.INTENSITY` or
51
            :attr:`torchio.LABEL`. This will be used by the transforms to
52
            decide whether to apply an operation, or which interpolation to use
53
            when resampling. For example, `preprocessing`_ and `augmentation`_
54
            intensity transforms will only be applied to images with type
55
            :attr:`torchio.INTENSITY`. Spatial transforms will be applied to
56
            all types, and nearest neighbor interpolation is always used to
57
            resample images with type :attr:`torchio.LABEL`.
58
            The type :attr:`torchio.SAMPLING_MAP` may be used with instances of
59
            :py:class:`~torchio.data.sampler.weighted.WeightedSampler`.
60
        tensor: If :py:attr:`path` is not given, :attr:`tensor` must be a 4D
61
            :py:class:`torch.Tensor` or NumPy array with dimensions
62
            :math:`(C, D, H, W)`. If it is not 4D, TorchIO will try to guess
63
            the dimensions meanings. If 2D, the shape will be interpreted as
64
            :math:`(H, W)`. If 3D, the number of spatial dimensions should be
65
            determined in :attr:`num_spatial_dims`. If :attr:`num_spatial_dims`
66
            is not given and the shape is 3 along the first or last dimensions,
67
            it will be interpreted as a multichannel 2D image. Otherwise, it
68
            be interpreted as a 3D image with a single channel.
69
        affine: If :attr:`path` is not given, :attr:`affine` must be a
70
            :math:`4 \times 4` NumPy array. If ``None``, :attr:`affine` is an
71
            identity matrix.
72
        check_nans: If ``True``, issues a warning if NaNs are found
73
            in the image. If ``False``, images will not be checked for the
74
            presence of NaNs.
75
        num_spatial_dims: If ``2`` and the input tensor has 3 dimensions, it
76
            will be interpreted as a multichannel 2D image. If ``3`` and the
77
            input has 3 dimensions, it will be interpreted as a
78
            single-channel 3D volume.
79
        channels_last: If ``True``, the last dimension of the input will be
80
            interpreted as the channels. Defaults to ``True`` if :attr:`path` is
81
            given and ``False`` otherwise.
82
        **kwargs: Items that will be added to the image dictionary, e.g.
83
            acquisition parameters.
84
85
    Example:
86
        >>> import torch
87
        >>> import torchio
88
        >>> # Loading from a file
89
        >>> t1_image = torchio.Image('t1.nii.gz', type=torchio.INTENSITY)
90
        >>> label_image = torchio.Image('t1_seg.nii.gz', type=torchio.LABEL)
91
        >>> image = torchio.Image(tensor=torch.rand(3, 4, 5))
92
        >>> image = torchio.Image('safe_image.nrrd', check_nans=False)
93
        >>> data, affine = image.data, image.affine
94
        >>> affine.shape
95
        (4, 4)
96
        >>> image.data is image[torchio.DATA]
97
        True
98
        >>> image.data is image.tensor
99
        True
100
        >>> type(image.data)
101
        torch.Tensor
102
103
    TorchIO images are `lazy loaders`_, i.e. the data is only loaded from disk
104
    when needed.
105
106
    Example:
107
        >>> import torchio
108
        >>> image = torchio.Image('t1.nii.gz')
109
        >>> image  # not loaded yet
110
        Image(path: t1.nii.gz; type: intensity)
111
        >>> times_two = 2 * image.data  # data is loaded and cached here
112
        >>> image
113
        Image(shape: (1, 256, 256, 176); spacing: (1.00, 1.00, 1.00); orientation: PIR+; memory: 44.0 MiB; type: intensity)
114
        >>> image.save('doubled_image.nii.gz')
115
116
    .. _lazy loaders: https://en.wikipedia.org/wiki/Lazy_loading
117
    .. _preprocessing: https://torchio.readthedocs.io/transforms/preprocessing.html#intensity
118
    .. _augmentation: https://torchio.readthedocs.io/transforms/augmentation.html#intensity
119
    .. _NiBabel docs: https://nipy.org/nibabel/image_orientation.html
120
    .. _3D Slicer wiki: https://www.slicer.org/wiki/Coordinate_systems
121
    .. _FSL docs: https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Orientation%20Explained
122
    .. _SimpleITK docs: https://simpleitk.readthedocs.io/en/master/fundamentalConcepts.html
123
    .. _Graham Wideman's website: http://www.grahamwideman.com/gw/brain/orientation/orientterms.htm
124
    """
125
    def __init__(
126
            self,
127
            path: Optional[TypePath] = None,
128
            type: str = None,
129
            tensor: Optional[TypeData] = None,
130
            affine: Optional[TypeData] = None,
131
            check_nans: bool = True,
132
            num_spatial_dims: Optional[int] = None,
133
            channels_last: Optional[bool] = None,
134
            **kwargs: Dict[str, Any],
135
            ):
136
        self.check_nans = check_nans
137
        self.num_spatial_dims = num_spatial_dims
138
139
        if type is None:
140
            warnings.warn(
141
                'Not specifying the image type is deprecated and will be'
142
                ' mandatory in the future. You can probably use ScalarImage or'
143
                ' LabelMap instead'
144
            )
145
            type = INTENSITY
146
147
        if path is None and tensor is None:
148
            raise ValueError('A value for path or tensor must be given')
149
        self._loaded = False
150
151
        # Number of channels are typically stored in the last dimensions in disk
152
        # But if a tensor is given, the channels should be in the first dim
153
        if channels_last is None:
154
            channels_last = path is not None
155
        self.channels_last = channels_last
156
157
        tensor = self.parse_tensor(tensor)
158
        affine = self.parse_affine(affine)
159
        if tensor is not None:
160
            self[DATA] = tensor
161
            self[AFFINE] = affine
162
            self._loaded = True
163
        for key in PROTECTED_KEYS:
164
            if key in kwargs:
165
                message = f'Key "{key}" is reserved. Use a different one'
166
                raise ValueError(message)
167
168
        super().__init__(**kwargs)
169
        self.path = self._parse_path(path)
170
        self[PATH] = '' if self.path is None else str(self.path)
171
        self[STEM] = '' if self.path is None else get_stem(self.path)
172
        self[TYPE] = type
173
174
    def __repr__(self):
175
        properties = []
176
        if self._loaded:
177
            properties.extend([
178
                f'shape: {self.shape}',
179
                f'spacing: {self.get_spacing_string()}',
180
                f'orientation: {"".join(self.orientation)}+',
181
                f'memory: {humanize.naturalsize(self.memory, binary=True)}',
182
            ])
183
        else:
184
            properties.append(f'path: "{self.path}"')
185
        properties.append(f'type: {self.type}')
186
        properties = '; '.join(properties)
187
        string = f'{self.__class__.__name__}({properties})'
188
        return string
189
190
    def __getitem__(self, item):
191
        if item in (DATA, AFFINE):
192
            if item not in self:
193
                self._load()
194
        return super().__getitem__(item)
195
196
    def __array__(self):
197
        return self[DATA].numpy()
198
199
    def __copy__(self):
200
        kwargs = dict(
201
            tensor=self.data,
202
            affine=self.affine,
203
            type=self.type,
204
            path=self.path,
205
            channels_last=False,
206
        )
207
        for key, value in self.items():
208
            if key in PROTECTED_KEYS: continue
209
            kwargs[key] = value  # should I copy? deepcopy?
210
        return self.__class__(**kwargs)
211
212
    @property
213
    def data(self):
214
        return self[DATA]
215
216
    @property
217
    def tensor(self):
218
        return self.data
219
220
    @property
221
    def affine(self):
222
        return self[AFFINE]
223
224
    @property
225
    def type(self):
226
        return self[TYPE]
227
228
    @property
229
    def shape(self) -> Tuple[int, int, int, int]:
230
        return tuple(self.data.shape)
231
232
    @property
233
    def spatial_shape(self) -> TypeTripletInt:
234
        return self.shape[1:]
235
236
    @property
237
    def orientation(self):
238
        return nib.aff2axcodes(self.affine)
239
240
    @property
241
    def spacing(self):
242
        _, spacing = get_rotation_and_spacing_from_affine(self.affine)
243
        return tuple(spacing)
244
245
    @property
246
    def memory(self):
247
        return np.prod(self.shape) * 4  # float32, i.e. 4 bytes per voxel
248
249
    def get_spacing_string(self):
250
        strings = [f'{n:.2f}' for n in self.spacing]
251
        string = f'({", ".join(strings)})'
252
        return string
253
254
    @staticmethod
255
    def _parse_path(path: TypePath) -> Path:
256
        if path is None:
257
            return None
258
        try:
259
            path = Path(path).expanduser()
260
        except TypeError:
261
            message = f'Conversion to path not possible for variable: {path}'
262
            raise TypeError(message)
263
        if not (path.is_file() or path.is_dir()):  # might be a dir with DICOM
264
            raise FileNotFoundError(f'File not found: {path}')
265
        return path
266
267
    def parse_tensor(self, tensor: TypeData) -> torch.Tensor:
268
        if tensor is None:
269
            return None
270
        if isinstance(tensor, np.ndarray):
271
            tensor = torch.from_numpy(tensor)
272
        tensor = self.parse_tensor_shape(tensor)
273
        if self.check_nans and torch.isnan(tensor).any():
274
            warnings.warn(f'NaNs found in tensor')
275
        return tensor
276
277
    def parse_tensor_shape(self, tensor: torch.Tensor) -> torch.Tensor:
278
        return ensure_4d(tensor, self.channels_last, self.num_spatial_dims)
279
280
    @staticmethod
281
    def parse_affine(affine: np.ndarray) -> np.ndarray:
282
        if affine is None:
283
            return np.eye(4)
284
        if not isinstance(affine, np.ndarray):
285
            raise TypeError(f'Affine must be a NumPy array, not {type(affine)}')
286
        if affine.shape != (4, 4):
287
            raise ValueError(f'Affine shape must be (4, 4), not {affine.shape}')
288
        return affine
289
290
    def _load(self) -> Tuple[torch.Tensor, np.ndarray]:
291
        r"""Load the image from disk.
292
293
        Returns:
294
            Tuple containing a 4D tensor of size :math:`(C, D, H, W)` and a 2D
295
            :math:`4 \times 4` affine matrix to convert voxel indices to world
296
            coordinates.
297
        """
298
        if self._loaded:
299
            return
300
        tensor, affine = read_image(self.path)
301
        tensor = self.parse_tensor_shape(tensor)
302
303
        if self.check_nans and torch.isnan(tensor).any():
304
            warnings.warn(f'NaNs found in file "{self.path}"')
305
        self[DATA] = tensor
306
        self[AFFINE] = affine
307
        self._loaded = True
308
309
    def save(self, path, squeeze=True, channels_last=True):
310
        """Save image to disk.
311
312
        Args:
313
            path: String or instance of :py:class:`pathlib.Path`.
314
            squeeze: If ``True``, the singleton dimensions will be removed
315
                before saving.
316
            channels_last: If ``True``, the channels will be saved in the last
317
                dimension.
318
        """
319
        write_image(
320
            self[DATA],
321
            self[AFFINE],
322
            path,
323
            squeeze=squeeze,
324
            channels_last=channels_last,
325
        )
326
327
    def is_2d(self) -> bool:
328
        return self.shape[-3] == 1
329
330
    def numpy(self) -> np.ndarray:
331
        """Get a NumPy array containing the image data."""
332
        return np.asarray(self)
333
334
    def as_sitk(self) -> sitk.Image:
335
        """Get the image as an instance of :py:class:`sitk.Image`."""
336
        return nib_to_sitk(self[DATA], self[AFFINE])
337
338
    def get_center(self, lps: bool = False) -> TypeTripletFloat:
339
        """Get image center in RAS+ or LPS+ coordinates.
340
341
        Args:
342
            lps: If ``True``, the coordinates will be in LPS+ orientation, i.e.
343
                the first dimension grows towards the left, etc. Otherwise, the
344
                coordinates will be in RAS+ orientation.
345
        """
346
        size = np.array(self.spatial_shape)
347
        center_index = (size - 1) / 2
348
        r, a, s = nib.affines.apply_affine(self.affine, center_index)
349
        if lps:
350
            return (-r, -a, s)
351
        else:
352
            return (r, a, s)
353
354
    def set_check_nans(self, check_nans: bool):
355
        self.check_nans = check_nans
356
357
    def crop(self, index_ini: TypeTripletInt, index_fin: TypeTripletInt):
358
        new_origin = nib.affines.apply_affine(self.affine, index_ini)
359
        new_affine = self.affine.copy()
360
        new_affine[:3, 3] = new_origin
361
        i0, j0, k0 = index_ini
362
        i1, j1, k1 = index_fin
363
        patch = self.data[:, i0:i1, j0:j1, k0:k1].clone()
364
        kwargs = dict(
365
            tensor=patch,
366
            affine=new_affine,
367
            type=self.type,
368
            path=self.path,
369
            channels_last=False,
370
        )
371
        for key, value in self.items():
372
            if key in PROTECTED_KEYS: continue
373
            kwargs[key] = value  # should I copy? deepcopy?
374
        return self.__class__(**kwargs)
375
376
377
class ScalarImage(Image):
378
    """Alias for :py:class:`~torchio.Image` of type :py:attr:`torchio.INTENSITY`.
379
380
    Example:
381
        >>> import torch
382
        >>> import torchio
383
        >>> image = torchio.ScalarImage('t1.nii.gz')  # loading from a file
384
        >>> image = torchio.ScalarImage(tensor=torch.rand(128, 128, 68))  # from tensor
385
        >>> data, affine = image.data, image.affine
386
        >>> affine.shape
387
        (4, 4)
388
        >>> image.data is image[torchio.DATA]
389
        True
390
        >>> image.data is image.tensor
391
        True
392
        >>> type(image.data)
393
        torch.Tensor
394
395
    See :py:class:`~torchio.Image` for more information.
396
397
    Raises:
398
        ValueError: A :py:attr:`type` is used for instantiation.
399
    """
400
    def __init__(self, *args, **kwargs):
401
        if 'type' in kwargs and kwargs['type'] != INTENSITY:
402
            raise ValueError('Type of ScalarImage is always torchio.INTENSITY')
403
        kwargs.update({'type': INTENSITY})
404
        super().__init__(*args, **kwargs)
405
406
407
class LabelMap(Image):
408
    """Alias for :py:class:`~torchio.Image` of type :py:attr:`torchio.LABEL`.
409
410
    Example:
411
        >>> import torch
412
        >>> import torchio
413
        >>> labels = torchio.LabelMap(tensor=torch.rand(128, 128, 68) > 0.5)
414
        >>> labels = torchio.LabelMap('t1_seg.nii.gz')  # loading from a file
415
416
    See :py:class:`~torchio.data.image.Image` for more information.
417
418
    Raises:
419
        ValueError: If a value for :py:attr:`type` is given.
420
    """
421
    def __init__(self, *args, **kwargs):
422
        if 'type' in kwargs and kwargs['type'] != LABEL:
423
            raise ValueError('Type of LabelMap is always torchio.LABEL')
424
        kwargs.update({'type': LABEL})
425
        super().__init__(*args, **kwargs)
426