1 files changed, 54 insertions, 0 deletions
diff --git a/supervised/datautils.py b/supervised/datautils.py
index 196fca7..843f669 100644
--- a/supervised/datautils.py
+++ b/supervised/datautils.py
@@ -1,3 +1,5 @@
+import numpy as np
+import torch
 from torchvision.transforms import transforms
 
 
@@ -11,3 +13,55 @@ def color_distortion(s=1.0):
         rnd_gray
     ])
     return color_distort
+
+
+class Clip(object):
+    def __call__(self, x):
+        return torch.clamp(x, 0, 1)
+
+
+class RandomGaussianBlur(object):
+    """
+        PyTorch version of
+        https://github.com/google-research/simclr/blob/244e7128004c5fd3c7805cf3135c79baa6c3bb96/data_util.py#L311
+    """
+
+    def gaussian_blur(self, image, sigma):
+        image = image.reshape(1, 3, 224, 224)
+        radius = np.int(self.kernel_size / 2)
+        kernel_size = radius * 2 + 1
+        x = np.arange(-radius, radius + 1)
+
+        blur_filter = np.exp(
+            -np.power(x, 2.0) / (2.0 * np.power(np.float(sigma), 2.0)))
+        blur_filter /= np.sum(blur_filter)
+
+        conv1 = torch.nn.Conv2d(3, 3, kernel_size=(kernel_size, 1), groups=3,
+                                padding=[kernel_size // 2, 0], bias=False)
+        conv1.weight = torch.nn.Parameter(torch.Tensor(np.tile(
+            blur_filter.reshape(kernel_size, 1, 1, 1), 3
+        ).transpose([3, 2, 0, 1])))
+
+        conv2 = torch.nn.Conv2d(3, 3, kernel_size=(1, kernel_size), groups=3,
+                                padding=[0, kernel_size // 2], bias=False)
+        conv2.weight = torch.nn.Parameter(torch.Tensor(np.tile(
+            blur_filter.reshape(kernel_size, 1, 1, 1), 3
+        ).transpose([3, 2, 1, 0])))
+
+        res = conv2(conv1(image))
+        assert res.shape == image.shape
+        return res[0]
+
+    def __init__(self, kernel_size, sigma_range=(0.1, 2), p=0.5):
+        self.kernel_size = kernel_size
+        self.sigma_range = sigma_range
+        self.p = p
+
+    def __call__(self, img):
+        with torch.no_grad():
+            assert isinstance(img, torch.Tensor)
+            if np.random.uniform() < self.p:
+                return self.gaussian_blur(
+                    img, sigma=np.random.uniform(*self.sigma_range)
+                )
+            return img