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import os # when loading file paths | |
import pandas as pd # for lookup in annotation file | |
import spacy # for tokenizer | |
import torch | |
from torch.nn.utils.rnn import pad_sequence # pad batch | |
from torch.utils.data import DataLoader, Dataset | |
from PIL import Image # Load img | |
import torchvision.transforms as transforms | |
import json | |
# Download with: python -m spacy download en | |
spacy_eng = spacy.load("en_core_web_sm") | |
class Vocabulary: | |
def __init__(self, freq_threshold): | |
self.itos = {0: "<PAD>", 1: "<SOS>", 2: "<EOS>", 3: "<UNK>"} | |
self.stoi = {"<PAD>": 0, "<SOS>": 1, "<EOS>": 2, "<UNK>": 3} | |
self.freq_threshold = freq_threshold | |
def __len__(self): | |
return len(self.stoi) | |
def tokenizer_eng(text): | |
return [tok.text.lower() for tok in spacy_eng.tokenizer(text)] | |
def build_vocabulary(self, sentence_list): | |
frequencies = {} | |
idx = 4 | |
for sentence in sentence_list: | |
for word in self.tokenizer_eng(sentence): | |
if word not in frequencies: | |
frequencies[word] = 1 | |
else: | |
frequencies[word] += 1 | |
if frequencies[word] == self.freq_threshold: | |
self.stoi[word] = idx | |
self.itos[idx] = word | |
idx += 1 | |
def numericalize(self, text): | |
tokenized_text = self.tokenizer_eng(text) | |
return [ | |
self.stoi[token] if token in self.stoi else self.stoi["<UNK>"] | |
for token in tokenized_text | |
] | |
class FlickrDataset(Dataset): | |
def __init__(self, root_dir, captions_file, transform=None, freq_threshold=5): | |
self.root_dir = root_dir | |
self.df = pd.read_csv(captions_file) | |
self.transform = transform | |
# Get img, caption columns | |
self.imgs = self.df["image_name"] | |
self.captions = self.df["comment"] | |
# Initialize vocabulary and build vocab | |
self.vocab = Vocabulary(freq_threshold) | |
self.vocab.build_vocabulary(self.captions.tolist()) | |
def __len__(self): | |
return len(self.df) | |
def __getitem__(self, index): | |
caption = self.captions[index] | |
img_id = self.imgs[index] | |
img = Image.open(os.path.join(self.root_dir, img_id)).convert("RGB") | |
if self.transform is not None: | |
img = self.transform(img) | |
numericalized_caption = [self.vocab.stoi["<SOS>"]] | |
numericalized_caption += self.vocab.numericalize(caption) | |
numericalized_caption.append(self.vocab.stoi["<EOS>"]) | |
return img, torch.tensor(numericalized_caption) | |
class MyCollate: | |
def __init__(self, pad_idx): | |
self.pad_idx = pad_idx | |
def __call__(self, batch): | |
imgs = [item[0].unsqueeze(0) for item in batch] | |
imgs = torch.cat(imgs, dim=0) | |
targets = [item[1] for item in batch] | |
targets = pad_sequence(targets, batch_first=False, padding_value=self.pad_idx) | |
return imgs, targets | |
def get_loader( | |
root_folder, | |
annotation_file, | |
transform, | |
batch_size=64, | |
num_workers=2, | |
shuffle=True, | |
pin_memory=True, | |
): | |
dataset = FlickrDataset(root_folder, annotation_file, transform=transform) | |
pad_idx = dataset.vocab.stoi["<PAD>"] | |
loader = DataLoader( | |
dataset=dataset, | |
batch_size=batch_size, | |
num_workers=num_workers, | |
shuffle=shuffle, | |
pin_memory=pin_memory, | |
collate_fn=MyCollate(pad_idx=pad_idx), | |
) | |
return loader, dataset | |
if __name__ == "__main__": | |
transform = transforms.Compose( | |
[transforms.Resize((224, 224)), transforms.ToTensor(),] | |
) | |
loader, dataset = get_loader( | |
"/home/koushik/vscode/Projects/pytorch/img2text_v1/flickr30k/flickr30k_images/", "/home/koushik/vscode/Projects/pytorch/img2text_v1/flickr30k/results.csv", transform=transform | |
) | |
for idx, (imgs, captions) in enumerate(loader): | |
print(imgs.shape) | |
print(captions.shape) | |
print(len(dataset.vocab)) | |
test = {"itos":dataset.vocab.itos, "stoi": dataset.vocab.stoi} | |
json.dump(test, open('test.json', 'w')) | |
break | |