Add SRResize (#295)

* Add ReSampling

* Add ReSampling

* Fix docstring

* fix

* add generate-by-resize

* Rename

* update docstring

Co-authored-by: liyinshuo <[email protected]>

mmedit/datasets/pipelines/__init__.py

@@ -6,7 +6,6 @@
 from .compose import Compose
 from .crop import (Crop, CropAroundCenter, CropAroundFg, CropAroundUnknown,
                    CropLike, FixedCrop, ModCrop, PairedRandomCrop)
-from .down_sampling import RandomDownSampling
 from .formating import (Collect, FormatTrimap, GetMaskedImage, ImageToTensor,
                         ToTensor)
 from .generate_coordinate_and_cell import GenerateCoordinateAndCell
@@ -17,6 +16,7 @@
                           GenerateTrimap, GenerateTrimapWithDistTransform,
                           MergeFgAndBg, PerturbBg, TransformTrimap)
 from .normalization import Normalize, RescaleToZeroOne
+from .sr_resize import RandomDownSampling, SRResize
 
 __all__ = [
     'Collect', 'FormatTrimap', 'LoadImageFromFile', 'LoadMask',
@@ -29,7 +29,7 @@
     'GenerateFrameIndices', 'GenerateFrameIndiceswithPadding', 'FixedCrop',
     'LoadPairedImageFromFile', 'GenerateSoftSeg', 'GenerateSeg', 'PerturbBg',
     'CropAroundFg', 'GetSpatialDiscountMask', 'RandomDownSampling',
-    'GenerateTrimapWithDistTransform', 'TransformTrimap',
+    'GenerateTrimapWithDistTransform', 'TransformTrimap', 'SRResize',
     'GenerateCoordinateAndCell', 'GenerateSegmentIndices', 'MirrorSequence',
     'CropLike'
 ]

mmedit/datasets/pipelines/down_sampling.py → mmedit/datasets/pipelines/sr_resize.py

@@ -7,6 +7,76 @@
 from ..registry import PIPELINES
 
 
+@PIPELINES.register_module()
+class SRResize:
+    """Resize image by a scale, including upsampling and downsampling.
+
+        Image will be loaded from the input_key and the result will be saved
+            in the specified output_key (can equal to input_key).
+
+    Args:
+        scale (float): The resampling scale. scale > 0.
+            scale > 1: upsampling.
+            scale < 1: downsampling.
+        input_key (str): The input key.
+        output_key (str): The output key.
+        interpolation (str): Interpolation method, accepted values are
+            "nearest", "bilinear", "bicubic", "area", "lanczos" for 'cv2'
+            backend, "nearest", "bilinear", "bicubic", "box", "lanczos",
+            "hamming" for 'pillow' backend.
+            Default: "bicubic".
+        backend (str | None): The image resize backend type. Options are `cv2`,
+            `pillow`, `None`. If backend is None, the global imread_backend
+            specified by ``mmcv.use_backend()`` will be used.
+            Default: "pillow".
+    """
+
+    def __init__(self,
+                 scale,
+                 input_key,
+                 output_key,
+                 interpolation='bicubic',
+                 backend='pillow'):
+        self.scale = scale
+        self.input_key = input_key
+        self.output_key = output_key
+        self.interpolation = interpolation
+        self.backend = backend
+
+    def __call__(self, results):
+        """Call function.
+
+        Args:
+            results (dict): A dict containing the necessary information and
+                data for augmentation. self.input_key is required.
+
+        Returns:
+            dict: A dict containing the processed data and information.
+                supplement self.output_key to keys.
+        """
+        assert self.input_key in results, f'Cannot find {self.input_key}.'
+        image_in = results[self.input_key]
+        h_in, w_in = image_in.shape[:2]
+        h_out = math.floor(h_in * self.scale + 1e-9)
+        w_out = math.floor(w_in * self.scale + 1e-9)
+        image_out = resize_fn(image_in, (w_out, h_out), self.interpolation,
+                              self.backend)
+
+        results[self.output_key] = image_out
+
+        return results
+
+    def __repr__(self):
+        repr_str = self.__class__.__name__
+        repr_str += (f' scale={self.scale}, '
+                     f'input_key={self.input_key}, '
+                     f'output_key={self.output_key}, '
+                     f'interpolation={self.interpolation}, '
+                     f'backend={self.backend}')
+
+        return repr_str
+
+
 @PIPELINES.register_module()
 class RandomDownSampling:
     """Generate LQ image from GT (and crop), which will randomly pick a scale.
@@ -81,9 +151,11 @@ def __call__(self, results):
 
     def __repr__(self):
         repr_str = self.__class__.__name__
-        repr_str += (f'scale_min={self.scale_min}, '
+        repr_str += (f' scale_min={self.scale_min}, '
                      f'scale_max={self.scale_max}, '
-                     f'patch_size={self.patch_size}')
+                     f'patch_size={self.patch_size}, '
+                     f'interpolation={self.interpolation}, '
+                     f'backend={self.backend}')
 
         return repr_str
 

tests/test_sr_resize.py

@@ -0,0 +1,54 @@
+import numpy as np
+
+from mmedit.datasets.pipelines import RandomDownSampling, SRResize
+
+
+def test_random_down_sampling():
+    img1 = np.uint8(np.random.randn(480, 640, 3) * 255)
+    inputs1 = dict(gt=img1)
+    down_sampling1 = RandomDownSampling(
+        scale_min=1, scale_max=4, patch_size=None)
+    results1 = down_sampling1(inputs1)
+    assert set(list(results1.keys())) == set(['gt', 'lq', 'scale'])
+    assert repr(down_sampling1) == (
+        down_sampling1.__class__.__name__ +
+        f' scale_min={down_sampling1.scale_min}, ' +
+        f'scale_max={down_sampling1.scale_max}, ' +
+        f'patch_size={down_sampling1.patch_size}, ' +
+        f'interpolation={down_sampling1.interpolation}, ' +
+        f'backend={down_sampling1.backend}')
+
+    img2 = np.uint8(np.random.randn(480, 640, 3) * 255)
+    inputs2 = dict(gt=img2)
+    down_sampling2 = RandomDownSampling(
+        scale_min=1, scale_max=4, patch_size=48)
+    results2 = down_sampling2(inputs2)
+    assert set(list(results2.keys())) == set(['gt', 'lq', 'scale'])
+    assert repr(down_sampling2) == (
+        down_sampling2.__class__.__name__ +
+        f' scale_min={down_sampling2.scale_min}, ' +
+        f'scale_max={down_sampling2.scale_max}, ' +
+        f'patch_size={down_sampling2.patch_size}, ' +
+        f'interpolation={down_sampling2.interpolation}, ' +
+        f'backend={down_sampling2.backend}')
+
+
+def test_sr_resize():
+    img = np.uint8(np.random.randn(480, 640, 3) * 255)
+    inputs = dict(gt=img)
+    re_size = SRResize(scale=1 / 4, input_key='gt', output_key='lq')
+    results = re_size(inputs)
+    assert set(list(results.keys())) == set(['gt', 'lq'])
+    assert results['lq'].shape == (120, 160, 3)
+    assert repr(re_size) == (
+        re_size.__class__.__name__ + f' scale={re_size.scale}, ' +
+        f'input_key={re_size.input_key}, ' +
+        f'output_key={re_size.output_key}, ' +
+        f'interpolation={re_size.interpolation}, ' +
+        f'backend={re_size.backend}')
+
+    inputs = dict(gt=img)
+    re_size = SRResize(scale=2, input_key='gt', output_key='gt')
+    results = re_size(inputs)
+    assert set(list(results.keys())) == set(['gt'])
+    assert results['gt'].shape == (960, 1280, 3)