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# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved. | |
# SPDX-License-Identifier: Apache-2.0 | |
# | |
# Licensed under the Apache License, Version 2.0 (the "License"); | |
# you may not use this file except in compliance with the License. | |
# You may obtain a copy of the License at | |
# | |
# http://www.apache.org/licenses/LICENSE-2.0 | |
# | |
# Unless required by applicable law or agreed to in writing, software | |
# distributed under the License is distributed on an "AS IS" BASIS, | |
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
# See the License for the specific language governing permissions and | |
# limitations under the License. | |
from typing import Any, Optional | |
import torch | |
import torchvision.transforms.functional as transforms_F | |
from PIL import Image | |
def obtain_image_size(data_dict: dict, input_keys: list) -> tuple[int, int]: | |
r"""Function for obtaining the image size from the data dict. | |
Args: | |
data_dict (dict): Input data dict | |
input_keys (list): List of input keys | |
Returns: | |
width (int): Width of the input image | |
height (int): Height of the input image | |
""" | |
data1 = data_dict[input_keys[0]] | |
if isinstance(data1, Image.Image): | |
width, height = data1.size | |
elif isinstance(data1, torch.Tensor): | |
height, width = data1.size()[-2:] | |
else: | |
raise ValueError("data to random crop should be PIL Image or tensor") | |
return width, height | |
class Augmentor: | |
def __init__(self, input_keys: list, output_keys: Optional[list] = None, args: Optional[dict] = None) -> None: | |
r"""Base augmentor class | |
Args: | |
input_keys (list): List of input keys | |
output_keys (list): List of output keys | |
args (dict): Arguments associated with the augmentation | |
""" | |
self.input_keys = input_keys | |
self.output_keys = output_keys | |
self.args = args | |
def __call__(self, *args: Any, **kwds: Any) -> Any: | |
raise ValueError("Augmentor not implemented") | |
class ResizeSmallestSideAspectPreserving(Augmentor): | |
def __init__(self, input_keys: list, output_keys: Optional[list] = None, args: Optional[dict] = None) -> None: | |
super().__init__(input_keys, output_keys, args) | |
def __call__(self, data_dict: dict) -> dict: | |
r"""Performs aspect-ratio preserving resizing. | |
Image is resized to the dimension which has the smaller ratio of (size / target_size). | |
First we compute (w_img / w_target) and (h_img / h_target) and resize the image | |
to the dimension that has the smaller of these ratios. | |
Args: | |
data_dict (dict): Input data dict | |
Returns: | |
data_dict (dict): Output dict where images are resized | |
""" | |
if self.output_keys is None: | |
self.output_keys = self.input_keys | |
assert self.args is not None, "Please specify args in augmentations" | |
img_w, img_h = self.args["img_w"], self.args["img_h"] | |
orig_w, orig_h = obtain_image_size(data_dict, self.input_keys) | |
scaling_ratio = max((img_w / orig_w), (img_h / orig_h)) | |
target_size = (int(scaling_ratio * orig_h + 0.5), int(scaling_ratio * orig_w + 0.5)) | |
assert ( | |
target_size[0] >= img_h and target_size[1] >= img_w | |
), f"Resize error. orig {(orig_w, orig_h)} desire {(img_w, img_h)} compute {target_size}" | |
for inp_key, out_key in zip(self.input_keys, self.output_keys): | |
data_dict[out_key] = transforms_F.resize( | |
data_dict[inp_key], | |
size=target_size, # type: ignore | |
interpolation=getattr(self.args, "interpolation", transforms_F.InterpolationMode.BICUBIC), | |
antialias=True, | |
) | |
if out_key != inp_key: | |
del data_dict[inp_key] | |
return data_dict | |
class CenterCrop(Augmentor): | |
def __init__(self, input_keys: list, output_keys: Optional[list] = None, args: Optional[dict] = None) -> None: | |
super().__init__(input_keys, output_keys, args) | |
def __call__(self, data_dict: dict) -> dict: | |
r"""Performs center crop. | |
Args: | |
data_dict (dict): Input data dict | |
Returns: | |
data_dict (dict): Output dict where images are center cropped. | |
We also save the cropping parameters in the aug_params dict | |
so that it will be used by other transforms. | |
""" | |
assert ( | |
(self.args is not None) and ("img_w" in self.args) and ("img_h" in self.args) | |
), "Please specify size in args" | |
img_w, img_h = self.args["img_w"], self.args["img_h"] | |
orig_w, orig_h = obtain_image_size(data_dict, self.input_keys) | |
for key in self.input_keys: | |
data_dict[key] = transforms_F.center_crop(data_dict[key], [img_h, img_w]) | |
# We also add the aug params we use. This will be useful for other transforms | |
crop_x0 = (orig_w - img_w) // 2 | |
crop_y0 = (orig_h - img_h) // 2 | |
cropping_params = { | |
"resize_w": orig_w, | |
"resize_h": orig_h, | |
"crop_x0": crop_x0, | |
"crop_y0": crop_y0, | |
"crop_w": img_w, | |
"crop_h": img_h, | |
} | |
if "aug_params" not in data_dict: | |
data_dict["aug_params"] = dict() | |
data_dict["aug_params"]["cropping"] = cropping_params | |
data_dict["padding_mask"] = torch.zeros((1, cropping_params["crop_h"], cropping_params["crop_w"])) | |
return data_dict | |
class Normalize(Augmentor): | |
def __init__(self, input_keys: list, output_keys: Optional[list] = None, args: Optional[dict] = None) -> None: | |
super().__init__(input_keys, output_keys, args) | |
def __call__(self, data_dict: dict) -> dict: | |
r"""Performs data normalization. | |
Args: | |
data_dict (dict): Input data dict | |
Returns: | |
data_dict (dict): Output dict where images are center cropped. | |
""" | |
assert self.args is not None, "Please specify args" | |
mean = self.args["mean"] | |
std = self.args["std"] | |
for key in self.input_keys: | |
if isinstance(data_dict[key], torch.Tensor): | |
data_dict[key] = data_dict[key].to(dtype=torch.get_default_dtype()).div(255) | |
else: | |
data_dict[key] = transforms_F.to_tensor(data_dict[key]) # division by 255 is applied in to_tensor() | |
data_dict[key] = transforms_F.normalize(tensor=data_dict[key], mean=mean, std=std) | |
return data_dict | |