From 9b2c25d3c927b7533e5d7d9665b67962e4c6934b Mon Sep 17 00:00:00 2001
From: Jordan Gong <jordan.gong@protonmail.com>
Date: Thu, 17 Mar 2022 20:10:42 +0800
Subject: Move some utils to libs directory

---
 libs/datautils.py | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 libs/datautils.py

(limited to 'libs/datautils.py')

diff --git a/libs/datautils.py b/libs/datautils.py
new file mode 100644
index 0000000..843f669
--- /dev/null
+++ b/libs/datautils.py
@@ -0,0 +1,67 @@
+import numpy as np
+import torch
+from torchvision.transforms import transforms
+
+
+def color_distortion(s=1.0):
+    # s is the strength of color distortion.
+    color_jitter = transforms.ColorJitter(0.8 * s, 0.8 * s, 0.8 * s, 0.2 * s)
+    rnd_color_jitter = transforms.RandomApply([color_jitter], p=0.8)
+    rnd_gray = transforms.RandomGrayscale(p=0.2)
+    color_distort = transforms.Compose([
+        rnd_color_jitter,
+        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
-- 
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