Add normalize flag to transforms factory, allow return of non-normalized native dtype torch.Tensors

Author: rwightman

timm/data/transforms_factory.py

@@ -19,9 +19,10 @@
 def transforms_noaug_train(
         img_size: Union[int, Tuple[int, int]] = 224,
         interpolation: str = 'bilinear',
-        use_prefetcher: bool = False,
         mean: Tuple[float, ...] = IMAGENET_DEFAULT_MEAN,
         std: Tuple[float, ...] = IMAGENET_DEFAULT_STD,
+        use_prefetcher: bool = False,
+        normalize: bool = True,
 ):
     """ No-augmentation image transforms for training.
 
@@ -31,6 +32,7 @@ def transforms_noaug_train(
         mean: Image normalization mean.
         std: Image normalization standard deviation.
         use_prefetcher: Prefetcher enabled. Do not convert image to tensor or normalize.
+        normalize: Normalization tensor output w/ provided mean/std (if prefetcher not used).
 
     Returns:
 
@@ -45,6 +47,9 @@ def transforms_noaug_train(
     if use_prefetcher:
         # prefetcher and collate will handle tensor conversion and norm
         tfl += [ToNumpy()]
+    elif not normalize:
+        # when normalize disabled, converted to tensor without scaling, keep original dtype
+        tfl += [transforms.PILToTensor()]
     else:
         tfl += [
             transforms.ToTensor(),
@@ -77,6 +82,7 @@ def transforms_imagenet_train(
         re_count: int = 1,
         re_num_splits: int = 0,
         use_prefetcher: bool = False,
+        normalize: bool = True,
         separate: bool = False,
 ):
     """ ImageNet-oriented image transforms for training.
@@ -103,6 +109,7 @@ def transforms_imagenet_train(
         re_count: Number of random erasing regions.
         re_num_splits: Control split of random erasing across batch size.
         use_prefetcher: Prefetcher enabled. Do not convert image to tensor or normalize.
+        normalize: Normalize tensor output w/ provided mean/std (if prefetcher not used).
         separate: Output transforms in 3-stage tuple.
 
     Returns:
@@ -209,12 +216,15 @@ def transforms_imagenet_train(
     if use_prefetcher:
         # prefetcher and collate will handle tensor conversion and norm
         final_tfl += [ToNumpy()]
+    elif not normalize:
+        # when normalize disable, converted to tensor without scaling, keeps original dtype
+        final_tfl += [transforms.PILToTensor()]
     else:
         final_tfl += [
             transforms.ToTensor(),
             transforms.Normalize(
                 mean=torch.tensor(mean),
-                std=torch.tensor(std)
+                std=torch.tensor(std),
             ),
         ]
         if re_prob > 0.:
@@ -243,6 +253,7 @@ def transforms_imagenet_eval(
         mean: Tuple[float, ...] = IMAGENET_DEFAULT_MEAN,
         std: Tuple[float, ...] = IMAGENET_DEFAULT_STD,
         use_prefetcher: bool = False,
+        normalize: bool = True,
 ):
     """ ImageNet-oriented image transform for evaluation and inference.
 
@@ -255,6 +266,7 @@ def transforms_imagenet_eval(
         mean: Image normalization mean.
         std: Image normalization standard deviation.
         use_prefetcher: Prefetcher enabled. Do not convert image to tensor or normalize.
+        normalize: Normalize tensor output w/ provided mean/std (if prefetcher not used).
 
     Returns:
         Composed transform pipeline
@@ -304,13 +316,16 @@ def transforms_imagenet_eval(
     if use_prefetcher:
         # prefetcher and collate will handle tensor conversion and norm
         tfl += [ToNumpy()]
+    elif not normalize:
+        # when normalize disabled, converted to tensor without scaling, keeps original dtype
+        tfl += [transforms.PILToTensor()]
     else:
         tfl += [
             transforms.ToTensor(),
             transforms.Normalize(
                 mean=torch.tensor(mean),
                 std=torch.tensor(std),
-            )
+            ),
         ]
 
     return transforms.Compose(tfl)
@@ -342,6 +357,7 @@ def create_transform(
         crop_border_pixels: Optional[int] = None,
         tf_preprocessing: bool = False,
         use_prefetcher: bool = False,
+        normalize: bool = True,
         separate: bool = False,
 ):
     """
@@ -373,6 +389,7 @@ def create_transform(
         crop_border_pixels: Inference crop border of specified # pixels around edge of original image.
         tf_preprocessing: Use TF 1.0 inference preprocessing for testing model ports
         use_prefetcher: Pre-fetcher enabled. Do not convert image to tensor or normalize.
+        normalize: Normalization tensor output w/ provided mean/std (if prefetcher not used).
         separate: Output transforms in 3-stage tuple.
 
     Returns:
@@ -397,9 +414,10 @@ def create_transform(
             transform = transforms_noaug_train(
                 img_size,
                 interpolation=interpolation,
-                use_prefetcher=use_prefetcher,
                 mean=mean,
                 std=std,
+                use_prefetcher=use_prefetcher,
+                normalize=normalize,
             )
         elif is_training:
             transform = transforms_imagenet_train(
@@ -415,26 +433,28 @@ def create_transform(
                 gaussian_blur_prob=gaussian_blur_prob,
                 auto_augment=auto_augment,
                 interpolation=interpolation,
-                use_prefetcher=use_prefetcher,
                 mean=mean,
                 std=std,
                 re_prob=re_prob,
                 re_mode=re_mode,
                 re_count=re_count,
                 re_num_splits=re_num_splits,
+                use_prefetcher=use_prefetcher,
+                normalize=normalize,
                 separate=separate,
             )
         else:
             assert not separate, "Separate transforms not supported for validation preprocessing"
             transform = transforms_imagenet_eval(
                 img_size,
                 interpolation=interpolation,
-                use_prefetcher=use_prefetcher,
                 mean=mean,
                 std=std,
                 crop_pct=crop_pct,
                 crop_mode=crop_mode,
                 crop_border_pixels=crop_border_pixels,
+                use_prefetcher=use_prefetcher,
+                normalize=normalize,
             )
 
     return transform