Add LANCZOS as default interplotation mode.

examples/controlnet/train_controlnet_sdxl.py

@@ -134,7 +134,17 @@ def log_validation(vae, unet, controlnet, args, accelerator, weight_dtype, step,
 
     for validation_prompt, validation_image in zip(validation_prompts, validation_images):
         validation_image = Image.open(validation_image).convert("RGB")
-        validation_image = validation_image.resize((args.resolution, args.resolution))
+
+        # Get the interpolation mode from string
+        try:
+            interpolation_mode = getattr(transforms.InterpolationMode, args.interpolation_type.upper())
+        except (AttributeError, KeyError):
+            interpolation_mode = transforms.InterpolationMode.LANCZOS
+
+        validation_image = validation_image.resize(
+            (args.resolution, args.resolution), 
+            resample=Image.Resampling.LANCZOS if interpolation_mode == transforms.InterpolationMode.LANCZOS else Image.Resampling.BILINEAR
+        )
 
         images = []
 
@@ -587,6 +597,16 @@ def parse_args(input_args=None):
             " more information see https://huggingface.co/docs/accelerate/v0.17.0/en/package_reference/accelerator#accelerate.Accelerator"
         ),
     )
+    parser.add_argument(
+        "--interpolation_type",
+        type=str,
+        default="lanczos",
+        help=(
+            "The interpolation method to use for resizing images. Choose between 'bilinear', 'bicubic', 'lanczos', "
+            "'nearest', 'nearest-exact', 'area', etc. See https://pytorch.org/vision/stable/transforms.html for all "
+            "options. Default is 'lanczos'."
+        ),
+    )
 
     if input_args is not None:
         args = parser.parse_args(input_args)
@@ -732,9 +752,18 @@ def encode_prompt(prompt_batch, text_encoders, tokenizers, proportion_empty_prom
 
 
 def prepare_train_dataset(dataset, accelerator):
+    # Get the interpolation mode from string
+    try:
+        interpolation_mode = getattr(transforms.InterpolationMode, args.interpolation_type.upper())
+    except (AttributeError, KeyError):
+        logger.warning(
+            f"Interpolation mode {args.interpolation_type} not found. Falling back to LANCZOS."
+        )
+        interpolation_mode = transforms.InterpolationMode.LANCZOS
+
     image_transforms = transforms.Compose(
         [
-            transforms.Resize(args.resolution, interpolation=transforms.InterpolationMode.BILINEAR),
+            transforms.Resize(args.resolution, interpolation=interpolation_mode),
             transforms.CenterCrop(args.resolution),
             transforms.ToTensor(),
             transforms.Normalize([0.5], [0.5]),
@@ -743,7 +772,7 @@ def prepare_train_dataset(dataset, accelerator):
 
     conditioning_image_transforms = transforms.Compose(
         [
-            transforms.Resize(args.resolution, interpolation=transforms.InterpolationMode.BILINEAR),
+            transforms.Resize(args.resolution, interpolation=interpolation_mode),
             transforms.CenterCrop(args.resolution),
             transforms.ToTensor(),
         ]