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import os
from PIL import Image
import matplotlib.pyplot as plt
import numpy as np
import torch
from torchvision import datasets
from torch.utils.data import Dataset, DataLoader, Sampler
import torchvision.transforms as T
# ImageNet Mean and Std values used for Normalization.
Imagenet_Mean = np.array([0.485, 0.456, 0.406])
Imagenet_Std = np.array([0.229, 0.224, 0.225])
def process_img(image_path: os.path, batch_size: int = 1, target_shape = None) -> torch.Tensor:
"""
Function to Pre-process image.
Args:
image_path -> Path of image.
batch_size -> To create batch of images.
target_shape -> Target size of output image.
"""
if not os.path.exists(image_path):
raise Exception(f"Path doesn't exist: {image_path}")
image = Image.open(image_path)
# image = cv2.imread(image_path)[:, :, ::-1]
if target_shape is not None:
if isinstance(target_shape, int) and target_shape != -1:
width, height = image.size
# height, width = image.shape[:2]
new_width = target_shape
new_height = int(height * (new_width / width))
image = image.resize((new_width, new_height))
# image = cv2.resize(image, (new_width, new_height), interpolation = cv2.INTER_CUBIC)
else:
image = image.resize((target_shape[0], target_shape[1]))
# image = cv2.resize(image, (target_shape[0], target_shape[1]), interpolation = cv2.INTER_CUBIC)
image = np.array(image).astype(np.float32)
# image = image.astype(np.float32)
image /= 255.0
transforms = T.Compose([T.ToTensor(),
T.Normalize(mean = Imagenet_Mean, std = Imagenet_Std)
])
image = transforms(image)
image = image.repeat(batch_size, 1, 1, 1)
return image
"""________________________________________________________________________________________________________________________________________________________________"""
"""Class to create a subset of data to be used for training."""
class SequentialSampler(Sampler):
def __init__(self, datasource, subset_size: int = None):
"""
Args:
datasource -> Torch Dataset.
subset_size -> Number of samples to be used.
"""
assert isinstance(datasource, Dataset) or isinstance(datasource, datasets.ImageFolder), "Datasource must be either Torch Dataset or Torchvision ImageFolder."
self.data_source = datasource
if subset_size is None:
subset_size = len(self.data_source)
assert 0 < subset_size <= len(self.data_source), f"Subset size must be between (0, {len(self.data_source)})."
self.subset_size = subset_size
def __iter__(self):
return iter(range(self.subset_size))
def __len__(self):
return self.subset_size
"""________________________________________________________________________________________________________________________________________________________________"""
def Train_DataLoader(training_config: dict) -> DataLoader:
"""
Function to create DataLoader for training.
Args:
training_config -> Dictionary of params config.
"""
transforms = T.Compose([T.Resize(training_config['image_size']),
T.CenterCrop(training_config['image_size']),
T.ToTensor(),
T.Normalize(mean = Imagenet_Mean, std = Imagenet_Std)
])
Train_dataset = datasets.ImageFolder(training_config['dataset_path'], transform = transforms)
sampler = SequentialSampler(Train_dataset, subset_size = training_config['subset_size'])
training_config['subset_size'] = len(sampler)
train_dl = DataLoader(Train_dataset, batch_size = training_config['batch_size'], sampler = sampler, drop_last = True)
return train_dl
"""________________________________________________________________________________________________________________________________________________________________"""
def gram_matrix(feature_map: torch.Tensor, should_mormalize: bool = True):
"""
Function to create Gram matrix.
Gram matrix - It captures the texture information from the feature maps extracted from convolutional
neural network. It is obtained using dot product between the feature maps. In other words,
it is a simple covariance matrix between different feature maps.
Args:
feature_map -> Feature extraced from pre-trained vision models.
should_normalize -> Should normalize the matrix.
"""
(b, ch, h, w) = feature_map.size()
features = feature_map.view(b, ch, h * w)
features_t = features.transpose(1, 2)
gram_mat = features.bmm(features_t)
if should_mormalize:
gram_mat = gram_mat / (ch * h * w)
return gram_mat
"""________________________________________________________________________________________________________________________________________________________________"""
def total_variation_loss(image_batch) -> torch.Tensor:
"""
Function for Total variation loss.
Used for spatial continuity between the pixels of the generated image, thereby denoising it and giving it visual coherence.
Args:
image_batch -> Batch of image tensors.
"""
batch_size = image_batch.shape[0]
tv_height = torch.sum(torch.abs(image_batch[:, :, :-1, :] - image_batch[:, :, 1:, :]))
tv_width = torch.sum(torch.abs(image_batch[:, :, :, :-1]) - image_batch[:, :, :, 1:])
return (tv_height + tv_width) / batch_size
"""________________________________________________________________________________________________________________________________________________________________"""
def post_process_img(image: np.ndarray) -> np.ndarray:
"""
Function to post process the generated image.
Args:
image -> Numpy array of generated image.
"""
assert isinstance(image, np.ndarray), f"Expected Numpy Array, but got {type(image)}"
mean = Imagenet_Mean.reshape(-1, 1, 1)
std = Imagenet_Std.reshape(-1, 1, 1)
image = (image * std) + mean
image = (np.clip(image, 0., 1.) * 255).astype(np.uint8)
image = np.moveaxis(image, 0, 2)
return image
"""________________________________________________________________________________________________________________________________________________________________"""
def save_and_display(config: dict, image: np.ndarray, should_display: bool = False, index: int = None):
"""
Function to save and display images.
Args:
config -> Dictionary of config.
image -> Numpy array of image.
should_display -> To display image.
index -> Index of generated image during training.
"""
assert isinstance(image, np.ndarray), f"Expected Numpy Array, but got {type(image)}"
image = post_process_img(image)
if index is not None:
fake_fname = 'generated-images-{0:0=4d}.jpg'.format(index)
else:
fake_fname = f'Stylized-image-{config["content_img_name"].split(".")[0]}.jpg'
os.makedirs(config['save_folder'], exist_ok = True)
plt.imsave(os.path.join(config['save_folder'], fake_fname), image)
# cv2.imwrite(os.path.join(config['save_folder'], fake_fname), image[:, :, ::-1])
if should_display:
plt.imshow(image)
plt.show()
"""________________________________________________________________________________________________________________________________________________________________"""
def print_parameters(model: torch.nn.Module) -> None:
"""
Function to print number of parameters.
Args:
model -> Torch model
"""
Num_of_parameters = sum(p.numel() for p in model.parameters())
print("Model Parameters : {:.3f} M".format(Num_of_parameters / 1e6))