/usr/local/lib/python3.6/site-packages/transformers/models/imagegpt
Edit: /usr/local/lib/python3.6/site-packages/transformers/models/imagegpt/feature_extraction_imagegpt.py (7231B)
# coding=utf-8
# Copyright 2021 The HuggingFace Inc. team. All rights reserved.
#
# 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.
"""Feature extractor class for ImageGPT."""
from typing import List, Optional, Union
import numpy as np
from PIL import Image
from ...feature_extraction_utils import BatchFeature, FeatureExtractionMixin
from ...image_utils import ImageFeatureExtractionMixin, is_torch_tensor
from ...utils import TensorType, logging
logger = logging.get_logger(__name__)
def squared_euclidean_distance(a, b):
b = b.T
a2 = np.sum(np.square(a), axis=1)
b2 = np.sum(np.square(b), axis=0)
ab = np.matmul(a, b)
d = a2[:, None] - 2 * ab + b2[None, :]
return d
def color_quantize(x, clusters):
x = x.reshape(-1, 3)
d = squared_euclidean_distance(x, clusters)
return np.argmin(d, axis=1)
class ImageGPTFeatureExtractor(FeatureExtractionMixin, ImageFeatureExtractionMixin):
r"""
Constructs an ImageGPT feature extractor. This feature extractor can be used to resize images to a smaller
resolution (such as 32x32 or 64x64), normalize them and finally color quantize them to obtain sequences of "pixel
values" (color clusters).
This feature extractor inherits from [`FeatureExtractionMixin`] which contains most of the main methods. Users
should refer to this superclass for more information regarding those methods.
Args:
clusters (`np.ndarray`):
The color clusters to use, as a `np.ndarray` of shape `(n_clusters, 3)`.
do_resize (`bool`, *optional*, defaults to `True`):
Whether to resize the input to a certain `size`.
size (`int` or `Tuple(int)`, *optional*, defaults to 32):
Resize the input to the given size. If a tuple is provided, it should be (width, height). If only an
integer is provided, then the input will be resized to (size, size). Only has an effect if `do_resize` is
set to `True`.
resample (`int`, *optional*, defaults to `PIL.Image.BILINEAR`):
An optional resampling filter. This can be one of `PIL.Image.NEAREST`, `PIL.Image.BOX`,
`PIL.Image.BILINEAR`, `PIL.Image.HAMMING`, `PIL.Image.BICUBIC` or `PIL.Image.LANCZOS`. Only has an effect
if `do_resize` is set to `True`.
do_normalize (`bool`, *optional*, defaults to `True`):
Whether or not to normalize the input to the range between -1 and +1.
"""
model_input_names = ["pixel_values"]
def __init__(self, clusters, do_resize=True, size=32, resample=Image.BILINEAR, do_normalize=True, **kwargs):
super().__init__(**kwargs)
self.clusters = np.asarray(clusters)
self.do_resize = do_resize
self.size = size
self.resample = resample
self.do_normalize = do_normalize
def normalize(self, image):
"""
Normalizes `image` into the range -1 to +1.
Args:
image (`PIL.Image.Image` or `np.ndarray` or `torch.Tensor`):
The image to normalize.
Returns:
`np.ndarray`: The normalized image.
"""
image = self.to_numpy_array(image, rescale=False, channel_first=False)
return image / 127.5 - 1
def __call__(
self,
images: Union[
Image.Image, np.ndarray, "torch.Tensor", List[Image.Image], List[np.ndarray], List["torch.Tensor"] # noqa
],
return_tensors: Optional[Union[str, TensorType]] = None,
**kwargs
) -> BatchFeature:
"""
Main method to prepare for the model one or several image(s).
NumPy arrays and PyTorch tensors are converted to PIL images when resizing, so the most efficient is to pass
PIL images.
Args:
images (`PIL.Image.Image`, `np.ndarray`, `torch.Tensor`, `List[PIL.Image.Image]`, `List[np.ndarray]`, `List[torch.Tensor]`):
The image or batch of images to be prepared. Each image can be a PIL image, NumPy array or PyTorch
tensor. In case of a NumPy array/PyTorch tensor, each image should be of shape (C, H, W), where C is a
number of channels, H and W are image height and width.
return_tensors (`str` or [`~utils.TensorType`], *optional*, defaults to `'np'`):
If set, will return tensors of a particular framework. Acceptable values are:
- `'tf'`: Return TensorFlow `tf.constant` objects.
- `'pt'`: Return PyTorch `torch.Tensor` objects.
- `'np'`: Return NumPy `np.ndarray` objects.
- `'jax'`: Return JAX `jnp.ndarray` objects.
Returns:
[`BatchFeature`]: A [`BatchFeature`] with the following fields:
- **pixel_values** -- Pixel values to be fed to a model, of shape (batch_size, num_channels, height,
width).
"""
# Input type checking for clearer error
valid_images = False
# Check that images has a valid type
if isinstance(images, (Image.Image, np.ndarray)) or is_torch_tensor(images):
valid_images = True
elif isinstance(images, (list, tuple)):
if len(images) == 0 or isinstance(images[0], (Image.Image, np.ndarray)) or is_torch_tensor(images[0]):
valid_images = True
if not valid_images:
raise ValueError(
"Images must of type `PIL.Image.Image`, `np.ndarray` or `torch.Tensor` (single example), "
"`List[PIL.Image.Image]`, `List[np.ndarray]` or `List[torch.Tensor]` (batch of examples)."
)
is_batched = bool(
isinstance(images, (list, tuple))
and (isinstance(images[0], (Image.Image, np.ndarray)) or is_torch_tensor(images[0]))
)
if not is_batched:
images = [images]
# transformations (resizing + normalization)
if self.do_resize and self.size is not None:
images = [self.resize(image, size=self.size, resample=self.resample) for image in images]
if self.do_normalize:
images = [self.normalize(image) for image in images]
# color quantize from (batch_size, height, width, 3) to (batch_size, height, width)
images = np.array(images)
images = color_quantize(images, self.clusters).reshape(images.shape[:-1])
# flatten to (batch_size, height*width)
batch_size = images.shape[0]
images = images.reshape(batch_size, -1)
# return as BatchFeature
data = {"pixel_values": images}
encoded_inputs = BatchFeature(data=data, tensor_type=return_tensors)
return encoded_inputs