Add option to use predefined aspect ratio buckets in the cropping tra…

…nsform (#157)

diffusion/datasets/image_caption.py

@@ -15,7 +15,8 @@
 from torch.utils.data import DataLoader
 from torchvision import transforms
 
-from diffusion.datasets.laion.transforms import LargestCenterSquare, RandomCropAspectRatioTransorm, RandomCropSquare
+from diffusion.datasets.laion.transforms import (LargestCenterSquare, RandomCropAspectRatioTransform,
+                                                 RandomCropBucketedAspectRatioTransform, RandomCropSquare)
 from diffusion.datasets.utils import make_streams
 from diffusion.models.text_encoder import MultiTokenizer
 
@@ -45,6 +46,7 @@ class StreamingImageCaptionDataset(StreamingDataset):
         transform (Callable, optional): The transforms to apply to the image. Default: ``None``.
         image_key (str): Key associated with the image in the streaming dataset. Default: ``'image'``.
         caption_key (str): Key associated with the caption in the streaming dataset. Default: ``'caption'``.
+        aspect_ratio_bucket_key (str, optional): Key associated with the aspect ratio bucket in the streaming dataset. Default: ``None``.
         sdxl_conditioning (bool): Whether or not to include SDXL microconditioning in a sample. Default: `False`.
         zero_dropped_captions (bool): If True, zero out text embeddings for dropped captions. Default: ``False``.
         **streaming_kwargs: Additional arguments to pass in the construction of the StreamingDataloader
@@ -63,6 +65,7 @@ def __init__(
         transform: Optional[Callable] = None,
         image_key: str = 'image',
         caption_key: str = 'caption',
+        aspect_ratio_bucket_key: Optional[str] = None,
         sdxl_conditioning: bool = False,
         zero_dropped_captions: bool = False,
         **streaming_kwargs,
@@ -90,6 +93,9 @@ def __init__(
         self.caption_selection = caption_selection
         self.image_key = image_key
         self.caption_key = caption_key
+        self.aspect_ratio_bucket_key = aspect_ratio_bucket_key
+        if isinstance(self.crop, RandomCropBucketedAspectRatioTransform):
+            assert self.aspect_ratio_bucket_key is not None, 'aspect_ratio_bucket_key must be provided when using RandomCropBucketedAspectRatioTransform'
         self.zero_dropped_captions = zero_dropped_captions
 
         self.tokenizer = tokenizer
@@ -107,7 +113,9 @@ def __getitem__(self, index):
         orig_w, orig_h = img.size
 
         # Image transforms
-        if self.crop is not None:
+        if isinstance(self.crop, RandomCropBucketedAspectRatioTransform):
+            img, crop_top, crop_left = self.crop(img, sample[self.aspect_ratio_bucket_key])
+        elif self.crop is not None:
             img, crop_top, crop_left = self.crop(img)
         else:
             crop_top, crop_left = 0, 0
@@ -179,6 +187,7 @@ def build_streaming_image_caption_dataloader(
     transform: Optional[List[Callable]] = None,
     image_key: str = 'image',
     caption_key: str = 'caption',
+    aspect_ratio_bucket_key: Optional[str] = None,
     crop_type: Optional[str] = 'square',
     zero_dropped_captions: bool = True,
     sdxl_conditioning: bool = False,
@@ -212,7 +221,8 @@ def build_streaming_image_caption_dataloader(
         transform (Optional[Callable]): The transforms to apply to the image. Default: ``None``.
         image_key (str): Key associated with the image in the streaming dataset. Default: ``'image'``.
         caption_key (str): Key associated with the caption in the streaming dataset. Default: ``'caption'``.
-        crop_type (str, optional): Type of crop to perform, either ['square', 'random', 'aspect_ratio'].
+        aspect_ratio_bucket_key (str, optional): Key associated with the aspect ratio bucket in the streaming dataset. Default: ``None``.
+        crop_type (str, optional): Type of crop to perform, either ['square', 'random', 'aspect_ratio', 'bucketed_aspect_ratio'].
             Default: ``'square'``.
         zero_dropped_captions (bool): If True, zero out text embeddings for dropped captions. Default: ``True``.
         sdxl_conditioning (bool): Whether or not to include SDXL microconditioning in a sample. Default: `False`.
@@ -225,12 +235,14 @@ def build_streaming_image_caption_dataloader(
     # Check crop type
     if crop_type is not None:
         crop_type = crop_type.lower()
-        if crop_type not in ['square', 'random', 'aspect_ratio']:
-            raise ValueError(f'Invalid crop_type: {crop_type}. Must be ["square", "random", "aspect_ratio", None]')
-        if crop_type == 'aspect_ratio' and (isinstance(resize_size, int) or isinstance(resize_size[0], int)):
+        if crop_type not in ['square', 'random', 'aspect_ratio', 'bucketed_aspect_ratio']:
             raise ValueError(
-                'If using crop_type="aspect_ratio", specify aspect ratio buckets in resize_size as a tuple of tuples.')
-
+                f'Invalid crop_type: {crop_type}. Must be ["square", "random", "aspect_ratio", "bucketed_aspect_ratio", None]'
+            )
+        if crop_type in ['aspect_ratio', 'bucketed_aspect_ratio'] and (isinstance(resize_size, int) or
+                                                                       isinstance(resize_size[0], int)):
+            raise ValueError(
+                'If using aspect ratio bucketing, specify aspect ratio buckets in resize_size as a tuple of tuples.')
     # Handle ``None`` kwargs
     if streaming_kwargs is None:
         streaming_kwargs = {}
@@ -246,7 +258,10 @@ def build_streaming_image_caption_dataloader(
     elif crop_type == 'random':
         crop = RandomCropSquare(resize_size)
     elif crop_type == 'aspect_ratio':
-        crop = RandomCropAspectRatioTransorm(resize_size, ar_bucket_boundaries)  # type: ignore
+        crop = RandomCropAspectRatioTransform(resize_size, ar_bucket_boundaries)  # type: ignore
+    elif crop_type == 'bucketed_aspect_ratio':
+        assert aspect_ratio_bucket_key is not None, 'aspect_ratio_bucket_key must be provided when using bucketed_aspect_ratio crop type'
+        crop = RandomCropBucketedAspectRatioTransform(resize_size)  # type: ignore
     else:
         crop = None
 
@@ -265,6 +280,7 @@ def build_streaming_image_caption_dataloader(
         transform=transform,
         image_key=image_key,
         caption_key=caption_key,
+        aspect_ratio_bucket_key=aspect_ratio_bucket_key,
         batch_size=batch_size,
         sdxl_conditioning=sdxl_conditioning,
         zero_dropped_captions=zero_dropped_captions,

diffusion/datasets/laion/transforms.py

@@ -3,6 +3,7 @@
 
 """Transforms for the training and eval dataset."""
 
+import math
 from typing import Optional, Tuple
 
 import torch
@@ -45,7 +46,7 @@ def __call__(self, img):
         return img, c_top, c_left
 
 
-class RandomCropAspectRatioTransorm:
+class RandomCropAspectRatioTransform:
     """Assigns an image to a arbitrary set of aspect ratio buckets, then resizes and crops to fit into the bucket.
 
     Args:
@@ -111,3 +112,49 @@ def __call__(self, img):
         c_top, c_left, height, width = transforms.RandomCrop.get_params(img, output_size=(target_height, target_width))
         img = crop(img, c_top, c_left, height, width)
         return img, c_top, c_left
+
+
+class RandomCropBucketedAspectRatioTransform:
+    """Assigns an image to a arbitrary set of aspect ratio buckets, then resizes and crops to fit into the bucket.
+
+    This transform requires the desired aspect ratio bucket to be specified manually in the call to the transform.
+
+    Args:
+        resize_size (Tuple[Tuple[int, int], ...): A tuple of 2-tuple integers representing the aspect ratio buckets.
+            The format is ((height_bucket1, width_bucket1), (height_bucket2, width_bucket2), ...).
+    """
+
+    def __init__(
+        self,
+        resize_size: Tuple[Tuple[int, int], ...],
+    ):
+        self.height_buckets = torch.tensor([size[0] for size in resize_size])
+        self.width_buckets = torch.tensor([size[1] for size in resize_size])
+        self.aspect_ratio_buckets = self.height_buckets / self.width_buckets
+        self.log_aspect_ratio_buckets = torch.log(self.aspect_ratio_buckets)
+
+    def __call__(self, img, aspect_ratio):
+        orig_w, orig_h = img.size
+        orig_aspect_ratio = orig_h / orig_w
+        # Figure out target H/W given the input aspect ratio
+        bucket_ind = torch.abs(self.log_aspect_ratio_buckets - math.log(aspect_ratio)).argmin()
+        target_width, target_height = self.width_buckets[bucket_ind].item(), self.height_buckets[bucket_ind].item()
+        target_aspect_ratio = target_height / target_width
+
+        # Determine resize size
+        if orig_aspect_ratio > target_aspect_ratio:
+            # Resize width and crop height
+            w_scale = target_width / orig_w
+            resize_size = (round(w_scale * orig_h), target_width)
+        elif orig_aspect_ratio < target_aspect_ratio:
+            # Resize height and crop width
+            h_scale = target_height / orig_h
+            resize_size = (target_height, round(h_scale * orig_w))
+        else:
+            resize_size = (target_height, target_width)
+        img = transforms.functional.resize(img, resize_size, antialias=True)
+
+        # Crop based on aspect ratio
+        c_top, c_left, height, width = transforms.RandomCrop.get_params(img, output_size=(target_height, target_width))
+        img = crop(img, c_top, c_left, height, width)
+        return img, c_top, c_left