Passed
Push — master ( 1e0c7f...57cb8b )
by Fernando
01:33 queued 36s
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
    def get_bounds(self):
255
        """Get image bounds in mm."""
256
        first_index = 3 * (-0.5,)
257
        last_index = np.array(self.spatial_shape) - 0.5
258
        first_point = nib.affines.apply_affine(self.affine, first_index)
259
        last_point = nib.affines.apply_affine(self.affine, last_index)
260
        array = np.array((first_point, last_point))
261
        bounds_x, bounds_y, bounds_z = array.T.tolist()
262
        return bounds_x, bounds_y, bounds_z
263
264
    @staticmethod
265
    def _parse_path(path: TypePath) -> Path:
266
        if path is None:
267
            return None
268
        try:
269
            path = Path(path).expanduser()
270
        except TypeError:
271
            message = f'Conversion to path not possible for variable: {path}'
272
            raise TypeError(message)
273
        if not (path.is_file() or path.is_dir()):  # might be a dir with DICOM
274
            raise FileNotFoundError(f'File not found: {path}')
275
        return path
276
277
    def parse_tensor(self, tensor: TypeData) -> torch.Tensor:
278
        if tensor is None:
279
            return None
280
        if isinstance(tensor, np.ndarray):
281
            tensor = torch.from_numpy(tensor)
282
        tensor = self.parse_tensor_shape(tensor)
283
        if self.check_nans and torch.isnan(tensor).any():
284
            warnings.warn(f'NaNs found in tensor')
285
        return tensor
286
287
    def parse_tensor_shape(self, tensor: torch.Tensor) -> torch.Tensor:
288
        return ensure_4d(tensor, self.channels_last, self.num_spatial_dims)
289
290
    @staticmethod
291
    def parse_affine(affine: np.ndarray) -> np.ndarray:
292
        if affine is None:
293
            return np.eye(4)
294
        if not isinstance(affine, np.ndarray):
295
            raise TypeError(f'Affine must be a NumPy array, not {type(affine)}')
296
        if affine.shape != (4, 4):
297
            raise ValueError(f'Affine shape must be (4, 4), not {affine.shape}')
298
        return affine
299
300
    def _load(self) -> Tuple[torch.Tensor, np.ndarray]:
301
        r"""Load the image from disk.
302
303
        Returns:
304
            Tuple containing a 4D tensor of size :math:`(C, D, H, W)` and a 2D
305
            :math:`4 \times 4` affine matrix to convert voxel indices to world
306
            coordinates.
307
        """
308
        if self._loaded:
309
            return
310
        tensor, affine = read_image(self.path)
311
        tensor = self.parse_tensor_shape(tensor)
312
313
        if self.check_nans and torch.isnan(tensor).any():
314
            warnings.warn(f'NaNs found in file "{self.path}"')
315
        self[DATA] = tensor
316
        self[AFFINE] = affine
317
        self._loaded = True
318
319
    def save(self, path, squeeze=True, channels_last=True):
320
        """Save image to disk.
321
322
        Args:
323
            path: String or instance of :py:class:`pathlib.Path`.
324
            squeeze: If ``True``, the singleton dimensions will be removed
325
                before saving.
326
            channels_last: If ``True``, the channels will be saved in the last
327
                dimension.
328
        """
329
        write_image(
330
            self[DATA],
331
            self[AFFINE],
332
            path,
333
            squeeze=squeeze,
334
            channels_last=channels_last,
335
        )
336
337
    def is_2d(self) -> bool:
338
        return self.shape[-3] == 1
339
340
    def numpy(self) -> np.ndarray:
341
        """Get a NumPy array containing the image data."""
342
        return np.asarray(self)
343
344
    def as_sitk(self) -> sitk.Image:
345
        """Get the image as an instance of :py:class:`sitk.Image`."""
346
        return nib_to_sitk(self[DATA], self[AFFINE])
347
348
    def get_center(self, lps: bool = False) -> TypeTripletFloat:
349
        """Get image center in RAS+ or LPS+ coordinates.
350
351
        Args:
352
            lps: If ``True``, the coordinates will be in LPS+ orientation, i.e.
353
                the first dimension grows towards the left, etc. Otherwise, the
354
                coordinates will be in RAS+ orientation.
355
        """
356
        size = np.array(self.spatial_shape)
357
        center_index = (size - 1) / 2
358
        r, a, s = nib.affines.apply_affine(self.affine, center_index)
359
        if lps:
360
            return (-r, -a, s)
361
        else:
362
            return (r, a, s)
363
364
    def set_check_nans(self, check_nans: bool):
365
        self.check_nans = check_nans
366
367
    def crop(self, index_ini: TypeTripletInt, index_fin: TypeTripletInt):
368
        new_origin = nib.affines.apply_affine(self.affine, index_ini)
369
        new_affine = self.affine.copy()
370
        new_affine[:3, 3] = new_origin
371
        i0, j0, k0 = index_ini
372
        i1, j1, k1 = index_fin
373
        patch = self.data[:, i0:i1, j0:j1, k0:k1].clone()
374
        kwargs = dict(
375
            tensor=patch,
376
            affine=new_affine,
377
            type=self.type,
378
            path=self.path,
379
            channels_last=False,
380
        )
381
        for key, value in self.items():
382
            if key in PROTECTED_KEYS: continue
383
            kwargs[key] = value  # should I copy? deepcopy?
384
        return self.__class__(**kwargs)
385
386
387
class ScalarImage(Image):
388
    """Alias for :py:class:`~torchio.Image` of type :py:attr:`torchio.INTENSITY`.
389
390
    Example:
391
        >>> import torch
392
        >>> import torchio
393
        >>> image = torchio.ScalarImage('t1.nii.gz')  # loading from a file
394
        >>> image = torchio.ScalarImage(tensor=torch.rand(128, 128, 68))  # from tensor
395
        >>> data, affine = image.data, image.affine
396
        >>> affine.shape
397
        (4, 4)
398
        >>> image.data is image[torchio.DATA]
399
        True
400
        >>> image.data is image.tensor
401
        True
402
        >>> type(image.data)
403
        torch.Tensor
404
405
    See :py:class:`~torchio.Image` for more information.
406
407
    Raises:
408
        ValueError: A :py:attr:`type` is used for instantiation.
409
    """
410
    def __init__(self, *args, **kwargs):
411
        if 'type' in kwargs and kwargs['type'] != INTENSITY:
412
            raise ValueError('Type of ScalarImage is always torchio.INTENSITY')
413
        kwargs.update({'type': INTENSITY})
414
        super().__init__(*args, **kwargs)
415
416
417
class LabelMap(Image):
418
    """Alias for :py:class:`~torchio.Image` of type :py:attr:`torchio.LABEL`.
419
420
    Example:
421
        >>> import torch
422
        >>> import torchio
423
        >>> labels = torchio.LabelMap(tensor=torch.rand(128, 128, 68) > 0.5)
424
        >>> labels = torchio.LabelMap('t1_seg.nii.gz')  # loading from a file
425
426
    See :py:class:`~torchio.data.image.Image` for more information.
427
428
    Raises:
429
        ValueError: If a value for :py:attr:`type` is given.
430
    """
431
    def __init__(self, *args, **kwargs):
432
        if 'type' in kwargs and kwargs['type'] != LABEL:
433
            raise ValueError('Type of LabelMap is always torchio.LABEL')
434
        kwargs.update({'type': LABEL})
435
        super().__init__(*args, **kwargs)
436