diff options
Diffstat (limited to 'src/text_recognizer/datasets')
| -rw-r--r-- | src/text_recognizer/datasets/__init__.py | 3 | ||||
| -rw-r--r-- | src/text_recognizer/datasets/iam_preprocessor.py | 196 | ||||
| -rw-r--r-- | src/text_recognizer/datasets/transforms.py | 45 |
3 files changed, 243 insertions, 1 deletions
diff --git a/src/text_recognizer/datasets/__init__.py b/src/text_recognizer/datasets/__init__.py index d8372e3..a6c1c59 100644 --- a/src/text_recognizer/datasets/__init__.py +++ b/src/text_recognizer/datasets/__init__.py @@ -8,6 +8,7 @@ from .emnist_lines_dataset import ( from .iam_dataset import IamDataset from .iam_lines_dataset import IamLinesDataset from .iam_paragraphs_dataset import IamParagraphsDataset +from .iam_preprocessor import load_metadata, Preprocessor from .transforms import AddTokens, Transpose from .util import ( _download_raw_dataset, @@ -29,8 +30,10 @@ __all__ = [ "EmnistMapper", "EmnistLinesDataset", "get_samples_by_character", + "load_metadata", "IamDataset", "IamLinesDataset", "IamParagraphsDataset", + "Preprocessor", "Transpose", ] diff --git a/src/text_recognizer/datasets/iam_preprocessor.py b/src/text_recognizer/datasets/iam_preprocessor.py new file mode 100644 index 0000000..5a5136c --- /dev/null +++ b/src/text_recognizer/datasets/iam_preprocessor.py @@ -0,0 +1,196 @@ +"""Preprocessor for extracting word letters from the IAM dataset. + +The code is mostly stolen from: + + https://github.com/facebookresearch/gtn_applications/blob/master/datasets/iamdb.py + +""" + +import collections +import itertools +from pathlib import Path +import re +from typing import List, Optional, Union + +import click +from loguru import logger +import torch + + +def load_metadata( + data_dir: Path, wordsep: str, use_words: bool = False +) -> collections.defaultdict: + """Loads IAM metadata and returns it as a dictionary.""" + forms = collections.defaultdict(list) + filename = "words.txt" if use_words else "lines.txt" + + with open(data_dir / "ascii" / filename, "r") as f: + lines = (line.strip().split() for line in f if line[0] != "#") + for line in lines: + # Skip word segmentation errors. + if use_words and line[1] == "err": + continue + text = " ".join(line[8:]) + + # Remove garbage tokens: + text = text.replace("#", "") + + # Swap word sep form | to wordsep + text = re.sub(r"\|+|\s", wordsep, text).strip(wordsep) + form_key = "-".join(line[0].split("-")[:2]) + line_key = "-".join(line[0].split("-")[:3]) + box_idx = 4 - use_words + box = tuple(int(val) for val in line[box_idx : box_idx + 4]) + forms[form_key].append({"key": line_key, "box": box, "text": text}) + return forms + + +class Preprocessor: + """A preprocessor for the IAM dataset.""" + + # TODO: add lower case only to when generating... + + def __init__( + self, + data_dir: Union[str, Path], + num_features: int, + tokens_path: Optional[Union[str, Path]] = None, + lexicon_path: Optional[Union[str, Path]] = None, + use_words: bool = False, + prepend_wordsep: bool = False, + ) -> None: + self.wordsep = "_" + self._use_word = use_words + self._prepend_wordsep = prepend_wordsep + + self.data_dir = Path(data_dir) + + self.forms = load_metadata(self.data_dir, self.wordsep, use_words=use_words) + + # Load the set of graphemes: + graphemes = set() + for _, form in self.forms.items(): + for line in form: + graphemes.update(line["text"].lower()) + self.graphemes = sorted(graphemes) + + # Build the token-to-index and index-to-token maps. + if tokens_path is not None: + with open(tokens_path, "r") as f: + self.tokens = [line.strip() for line in f] + else: + self.tokens = self.graphemes + + if lexicon_path is not None: + with open(lexicon_path, "r") as f: + lexicon = (line.strip().split() for line in f) + lexicon = {line[0]: line[1:] for line in lexicon} + self.lexicon = lexicon + else: + self.lexicon = None + + self.graphemes_to_index = {t: i for i, t in enumerate(self.graphemes)} + self.tokens_to_index = {t: i for i, t in enumerate(self.tokens)} + self.num_features = num_features + self.text = [] + + @property + def num_tokens(self) -> int: + """Returns the number or tokens.""" + return len(self.tokens) + + @property + def use_words(self) -> bool: + """If words are used.""" + return self._use_word + + def extract_train_text(self) -> None: + """Extracts training text.""" + keys = [] + with open(self.data_dir / "task" / "trainset.txt") as f: + keys.extend((line.strip() for line in f)) + + for _, examples in self.forms.items(): + for example in examples: + if example["key"] not in keys: + continue + self.text.append(example["text"].lower()) + + def to_index(self, line: str) -> torch.LongTensor: + """Converts text to a tensor of indices.""" + token_to_index = self.graphemes_to_index + if self.lexicon is not None: + if len(line) > 0: + # If the word is not found in the lexicon, fall back to letters. + line = [ + t + for w in line.split(self.wordsep) + for t in self.lexicon.get(w, self.wordsep + w) + ] + token_to_index = self.tokens_to_index + if self._prepend_wordsep: + line = itertools.chain([self.wordsep], line) + return torch.LongTensor([token_to_index[t] for t in line]) + + def to_text(self, indices: List[int]) -> str: + """Converts indices to text.""" + # Roughly the inverse of `to_index` + encoding = self.graphemes + if self.lexicon is not None: + encoding = self.tokens + return self._post_process(encoding[i] for i in indices) + + def tokens_to_text(self, indices: List[int]) -> str: + """Converts tokens to text.""" + return self._post_process(self.tokens[i] for i in indices) + + def _post_process(self, indices: List[int]) -> str: + """A list join.""" + return "".join(indices).strip(self.wordsep) + + +@click.command() +@click.option("--data_dir", type=str, default=None, help="Path to iam dataset") +@click.option( + "--use_words", is_flag=True, help="Load word segmented dataset instead of lines" +) +@click.option( + "--save_text", type=str, default=None, help="Path to save parsed train text" +) +@click.option("--save_tokens", type=str, default=None, help="Path to save tokens") +def cli( + data_dir: Optional[str], + use_words: bool, + save_text: Optional[str], + save_tokens: Optional[str], +) -> None: + """CLI for extracting text data from the iam dataset.""" + if data_dir is None: + data_dir = ( + Path(__file__).resolve().parents[3] / "data" / "raw" / "iam" / "iamdb" + ) + logger.debug(f"Using data dir: {data_dir}") + if not data_dir.exists(): + raise RuntimeError(f"Could not locate iamdb directory at {data_dir}") + else: + data_dir = Path(data_dir) + + preprocessor = Preprocessor(data_dir, 64, use_words=use_words) + preprocessor.extract_train_text() + + processed_dir = data_dir.parents[2] / "processed" / "iam_lines" + logger.debug(f"Saving processed files at: {processed_dir}") + + if save_text is not None: + logger.info("Saving training text") + with open(processed_dir / save_text, "w") as f: + f.write("\n".join(t for t in preprocessor.text)) + + if save_tokens is not None: + logger.info("Saving tokens") + with open(processed_dir / save_tokens, "w") as f: + f.write("\n".join(preprocessor.tokens)) + + +if __name__ == "__main__": + cli() diff --git a/src/text_recognizer/datasets/transforms.py b/src/text_recognizer/datasets/transforms.py index 8956b01..60987e0 100644 --- a/src/text_recognizer/datasets/transforms.py +++ b/src/text_recognizer/datasets/transforms.py @@ -1,14 +1,57 @@ """Transforms for PyTorch datasets.""" +import random + import numpy as np from PIL import Image import torch from torch import Tensor import torch.nn.functional as F -from torchvision.transforms import Compose, RandomAffine, RandomHorizontalFlip, ToTensor +from torchvision import transforms +from torchvision.transforms import ( + ColorJitter, + Compose, + Normalize, + RandomAffine, + RandomHorizontalFlip, + RandomRotation, + ToPILImage, + ToTensor, +) from text_recognizer.datasets.util import EmnistMapper +class RandomResizeCrop: + """Image transform with random resize and crop applied. + + Stolen from + + https://github.com/facebookresearch/gtn_applications/blob/master/datasets/iamdb.py + + """ + + def __init__(self, jitter: int = 10, ratio: float = 0.5) -> None: + self.jitter = jitter + self.ratio = ratio + + def __call__(self, img: np.ndarray) -> np.ndarray: + """Applies random crop and rotation to an image.""" + w, h = img.size + + # pad with white: + img = transforms.functional.pad(img, self.jitter, fill=255) + + # crop at random (x, y): + x = self.jitter + random.randint(-self.jitter, self.jitter) + y = self.jitter + random.randint(-self.jitter, self.jitter) + + # randomize aspect ratio: + size_w = w * random.uniform(1 - self.ratio, 1 + self.ratio) + size = (h, int(size_w)) + img = transforms.functional.resized_crop(img, y, x, h, w, size) + return img + + class Transpose: """Transposes the EMNIST image to the correct orientation.""" |