152-random-rotate (#155)

* Add RandomRotate.

monai/transforms/composables.py

@@ -85,7 +85,6 @@ def __init__(self, keys, affine_key, pixdim, interp_order=2, keep_shape=False, o
         interp_order = ensure_tuple(interp_order)
         self.interp_order = interp_order \
             if len(interp_order) == len(self.keys) else interp_order * len(self.keys)
-        print(self.interp_order)
         self.output_key = output_key
 
     def __call__(self, data):

monai/transforms/transforms.py

@@ -631,6 +631,56 @@ def __call__(self, img):
         return data
 
 
+@export
+class RandRotate(Randomizable):
+    """Randomly rotates the input arrays.
+
+    Args:
+        prob (float): Probability of rotation.
+        degrees (tuple of float or float): Range of rotation in degrees. If single number,
+            angle is picked from (-degrees, degrees). 
+        axes (tuple of 2 ints): Axes of rotation. Default: (1, 2). This is the first two
+            axis in spatial dimensions according to MONAI channel first shape assumption.
+        reshape (bool): If true, output shape is made same as input. Default: True.
+        order (int): Order of spline interpolation. Range 0-5. Default: 1. This is
+            different from scipy where default interpolation is 3.
+        mode (str): Points outside boundary filled according to this mode. Options are 
+            'constant', 'nearest', 'reflect', 'wrap'. Default: 'constant'.
+        cval (scalar): Value to fill outside boundary. Default: 0.
+        prefiter (bool): Apply spline_filter before interpolation. Default: True.
+    """
+
+    def __init__(self, degrees, prob=0.1, axes=(1, 2), reshape=True, order=1, 
+                 mode='constant', cval=0, prefilter=True):
+        self.prob = prob
+        self.degrees = degrees
+        self.reshape = reshape
+        self.order = order
+        self.mode = mode
+        self.cval = cval
+        self.prefilter = prefilter
+        self.axes = axes
+
+        if not hasattr(self.degrees, '__iter__'):
+            self.degrees = (-self.degrees, self.degrees)
+        assert len(self.degrees) == 2, "degrees should be a number or pair of numbers."
+
+        self._do_transform = False
+        self.angle = None
+
+    def randomize(self):
+        self._do_transform = self.R.random_sample() < self.prob
+        self.angle = self.R.uniform(low=self.degrees[0], high=self.degrees[1])
+
+    def __call__(self, img):
+        self.randomize()
+        if not self._do_transform:
+            return img
+        rotator = Rotate(self.angle, self.axes, self.reshape, self.order,
+                         self.mode, self.cval, self.prefilter)
+        return rotator(img)
+
+
 @export
 class RandomFlip(Randomizable):
     """Randomly flips the image along axes.

tests/test_random_rotate.py

@@ -0,0 +1,43 @@
+# Copyright 2020 MONAI Consortium
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#     http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+import numpy as np
+
+import scipy.ndimage
+from parameterized import parameterized
+
+from monai.transforms import RandRotate
+from tests.utils import NumpyImageTestCase2D
+
+
+class RandomRotateTest(NumpyImageTestCase2D):
+
+    @parameterized.expand([
+        (90, (1, 2), True, 1, 'reflect', 0, True),
+        ((-45, 45), (2, 1), True, 3, 'constant', 0, True),
+        (180, (2, 3), False, 2, 'constant', 4, False),
+    ])
+    def test_correct_results(self, degrees, axes, reshape, 
+                             order, mode, cval, prefilter):
+        rotate_fn = RandRotate(degrees, prob=1.0, axes=axes, reshape=reshape, 
+                               order=order, mode=mode, cval=cval, prefilter=prefilter)
+        rotate_fn.set_random_state(243)
+        rotated = rotate_fn(self.imt)
+
+        angle = rotate_fn.angle
+        expected = scipy.ndimage.rotate(self.imt, angle, axes, reshape, order=order,
+                                        mode=mode, cval=cval, prefilter=prefilter)
+        self.assertTrue(np.allclose(expected, rotated))
+
+
+if __name__ == '__main__':
+    unittest.main()