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-rw-r--r--text_recognizer/data/iam_paragraphs_dataset.py291
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diff --git a/text_recognizer/data/iam_paragraphs_dataset.py b/text_recognizer/data/iam_paragraphs_dataset.py
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-"""IamParagraphsDataset class and functions for data processing."""
-import random
-from typing import Callable, Dict, List, Optional, Tuple, Union
-
-import click
-import cv2
-import h5py
-from loguru import logger
-import numpy as np
-import torch
-from torch import Tensor
-from torchvision.transforms import ToTensor
-
-from text_recognizer import util
-from text_recognizer.datasets.dataset import Dataset
-from text_recognizer.datasets.iam_dataset import IamDataset
-from text_recognizer.datasets.util import (
- compute_sha256,
- DATA_DIRNAME,
- download_url,
- EmnistMapper,
-)
-
-INTERIM_DATA_DIRNAME = DATA_DIRNAME / "interim" / "iam_paragraphs"
-DEBUG_CROPS_DIRNAME = INTERIM_DATA_DIRNAME / "debug_crops"
-PROCESSED_DATA_DIRNAME = DATA_DIRNAME / "processed" / "iam_paragraphs"
-CROPS_DIRNAME = PROCESSED_DATA_DIRNAME / "crops"
-GT_DIRNAME = PROCESSED_DATA_DIRNAME / "gt"
-
-PARAGRAPH_BUFFER = 50 # Pixels in the IAM form images to leave around the lines.
-TEST_FRACTION = 0.2
-SEED = 4711
-
-
-class IamParagraphsDataset(Dataset):
- """IAM Paragraphs dataset for paragraphs of handwritten text."""
-
- def __init__(
- self,
- train: bool = False,
- subsample_fraction: float = None,
- transform: Optional[Callable] = None,
- target_transform: Optional[Callable] = None,
- ) -> None:
- super().__init__(
- train=train,
- subsample_fraction=subsample_fraction,
- transform=transform,
- target_transform=target_transform,
- )
- # Load Iam dataset.
- self.iam_dataset = IamDataset()
-
- self.num_classes = 3
- self._input_shape = (256, 256)
- self._output_shape = self._input_shape + (self.num_classes,)
- self._ids = None
-
- def __getitem__(self, index: Union[Tensor, int]) -> Tuple[Tensor, Tensor]:
- """Fetches data, target pair of the dataset for a given and index or indices.
-
- Args:
- index (Union[int, Tensor]): Either a list or int of indices/index.
-
- Returns:
- Tuple[Tensor, Tensor]: Data target pair.
-
- """
- if torch.is_tensor(index):
- index = index.tolist()
-
- data = self.data[index]
- targets = self.targets[index]
-
- seed = np.random.randint(SEED)
- random.seed(seed) # apply this seed to target tranfsorms
- torch.manual_seed(seed) # needed for torchvision 0.7
- if self.transform:
- data = self.transform(data)
-
- random.seed(seed) # apply this seed to target tranfsorms
- torch.manual_seed(seed) # needed for torchvision 0.7
- if self.target_transform:
- targets = self.target_transform(targets)
-
- return data, targets.long()
-
- @property
- def ids(self) -> Tensor:
- """Ids of the dataset."""
- return self._ids
-
- def get_data_and_target_from_id(self, id_: str) -> Tuple[Tensor, Tensor]:
- """Get data target pair from id."""
- ind = self.ids.index(id_)
- return self.data[ind], self.targets[ind]
-
- def load_or_generate_data(self) -> None:
- """Load or generate dataset data."""
- num_actual = len(list(CROPS_DIRNAME.glob("*.jpg")))
- num_targets = len(self.iam_dataset.line_regions_by_id)
-
- if num_actual < num_targets - 2:
- self._process_iam_paragraphs()
-
- self._data, self._targets, self._ids = _load_iam_paragraphs()
- self._get_random_split()
- self._subsample()
-
- def _get_random_split(self) -> None:
- np.random.seed(SEED)
- num_train = int((1 - TEST_FRACTION) * self.data.shape[0])
- indices = np.random.permutation(self.data.shape[0])
- train_indices, test_indices = indices[:num_train], indices[num_train:]
- if self.train:
- self._data = self.data[train_indices]
- self._targets = self.targets[train_indices]
- else:
- self._data = self.data[test_indices]
- self._targets = self.targets[test_indices]
-
- def _process_iam_paragraphs(self) -> None:
- """Crop the part with the text.
-
- For each page, crop out the part of it that correspond to the paragraph of text, and make sure all crops are
- self.input_shape. The ground truth data is the same size, with a one-hot vector at each pixel
- corresponding to labels 0=background, 1=odd-numbered line, 2=even-numbered line
- """
- crop_dims = self._decide_on_crop_dims()
- CROPS_DIRNAME.mkdir(parents=True, exist_ok=True)
- DEBUG_CROPS_DIRNAME.mkdir(parents=True, exist_ok=True)
- GT_DIRNAME.mkdir(parents=True, exist_ok=True)
- logger.info(
- f"Cropping paragraphs, generating ground truth, and saving debugging images to {DEBUG_CROPS_DIRNAME}"
- )
- for filename in self.iam_dataset.form_filenames:
- id_ = filename.stem
- line_region = self.iam_dataset.line_regions_by_id[id_]
- _crop_paragraph_image(filename, line_region, crop_dims, self.input_shape)
-
- def _decide_on_crop_dims(self) -> Tuple[int, int]:
- """Decide on the dimensions to crop out of the form image.
-
- Since image width is larger than a comfortable crop around the longest paragraph,
- we will make the crop a square form factor.
- And since the found dimensions 610x610 are pretty close to 512x512,
- we might as well resize crops and make it exactly that, which lets us
- do all kinds of power-of-2 pooling and upsampling should we choose to.
-
- Returns:
- Tuple[int, int]: A tuple of crop dimensions.
-
- Raises:
- RuntimeError: When max crop height is larger than max crop width.
-
- """
-
- sample_form_filename = self.iam_dataset.form_filenames[0]
- sample_image = util.read_image(sample_form_filename, grayscale=True)
- max_crop_width = sample_image.shape[1]
- max_crop_height = _get_max_paragraph_crop_height(
- self.iam_dataset.line_regions_by_id
- )
- if not max_crop_height <= max_crop_width:
- raise RuntimeError(
- f"Max crop height is larger then max crop width: {max_crop_height} >= {max_crop_width}"
- )
-
- crop_dims = (max_crop_width, max_crop_width)
- logger.info(
- f"Max crop width and height were found to be {max_crop_width}x{max_crop_height}."
- )
- logger.info(f"Setting them to {max_crop_width}x{max_crop_width}")
- return crop_dims
-
- def __repr__(self) -> str:
- """Return info about the dataset."""
- return (
- "IAM Paragraph Dataset\n" # pylint: disable=no-member
- f"Num classes: {self.num_classes}\n"
- f"Data: {self.data.shape}\n"
- f"Targets: {self.targets.shape}\n"
- )
-
-
-def _get_max_paragraph_crop_height(line_regions_by_id: Dict) -> int:
- heights = []
- for regions in line_regions_by_id.values():
- min_y1 = min(region["y1"] for region in regions) - PARAGRAPH_BUFFER
- max_y2 = max(region["y2"] for region in regions) + PARAGRAPH_BUFFER
- height = max_y2 - min_y1
- heights.append(height)
- return max(heights)
-
-
-def _crop_paragraph_image(
- filename: str, line_regions: Dict, crop_dims: Tuple[int, int], final_dims: Tuple
-) -> None:
- image = util.read_image(filename, grayscale=True)
-
- min_y1 = min(region["y1"] for region in line_regions) - PARAGRAPH_BUFFER
- max_y2 = max(region["y2"] for region in line_regions) + PARAGRAPH_BUFFER
- height = max_y2 - min_y1
- crop_height = crop_dims[0]
- buffer = (crop_height - height) // 2
-
- # Generate image crop.
- image_crop = 255 * np.ones(crop_dims, dtype=np.uint8)
- try:
- image_crop[buffer : buffer + height] = image[min_y1:max_y2]
- except Exception as e: # pylint: disable=broad-except
- logger.error(f"Rescued {filename}: {e}")
- return
-
- # Generate ground truth.
- gt_image = np.zeros_like(image_crop, dtype=np.uint8)
- for index, region in enumerate(line_regions):
- gt_image[
- (region["y1"] - min_y1 + buffer) : (region["y2"] - min_y1 + buffer),
- region["x1"] : region["x2"],
- ] = (index % 2 + 1)
-
- # Generate image for debugging.
- import matplotlib.pyplot as plt
-
- cmap = plt.get_cmap("Set1")
- image_crop_for_debug = np.dstack([image_crop, image_crop, image_crop])
- for index, region in enumerate(line_regions):
- color = [255 * _ for _ in cmap(index)[:-1]]
- cv2.rectangle(
- image_crop_for_debug,
- (region["x1"], region["y1"] - min_y1 + buffer),
- (region["x2"], region["y2"] - min_y1 + buffer),
- color,
- 3,
- )
- image_crop_for_debug = cv2.resize(
- image_crop_for_debug, final_dims, interpolation=cv2.INTER_AREA
- )
- util.write_image(image_crop_for_debug, DEBUG_CROPS_DIRNAME / f"{filename.stem}.jpg")
-
- image_crop = cv2.resize(image_crop, final_dims, interpolation=cv2.INTER_AREA)
- util.write_image(image_crop, CROPS_DIRNAME / f"{filename.stem}.jpg")
-
- gt_image = cv2.resize(gt_image, final_dims, interpolation=cv2.INTER_NEAREST)
- util.write_image(gt_image, GT_DIRNAME / f"{filename.stem}.png")
-
-
-def _load_iam_paragraphs() -> None:
- logger.info("Loading IAM paragraph crops and ground truth from image files...")
- images = []
- gt_images = []
- ids = []
- for filename in CROPS_DIRNAME.glob("*.jpg"):
- id_ = filename.stem
- image = util.read_image(filename, grayscale=True)
- image = 1.0 - image / 255
-
- gt_filename = GT_DIRNAME / f"{id_}.png"
- gt_image = util.read_image(gt_filename, grayscale=True)
-
- images.append(image)
- gt_images.append(gt_image)
- ids.append(id_)
- images = np.array(images).astype(np.float32)
- gt_images = np.array(gt_images).astype(np.uint8)
- ids = np.array(ids)
- return images, gt_images, ids
-
-
-@click.command()
-@click.option(
- "--subsample_fraction",
- type=float,
- default=None,
- help="The subsampling factor of the dataset.",
-)
-def main(subsample_fraction: float) -> None:
- """Load dataset and print info."""
- logger.info("Creating train set...")
- dataset = IamParagraphsDataset(train=True, subsample_fraction=subsample_fraction)
- dataset.load_or_generate_data()
- print(dataset)
- logger.info("Creating test set...")
- dataset = IamParagraphsDataset(subsample_fraction=subsample_fraction)
- dataset.load_or_generate_data()
- print(dataset)
-
-
-if __name__ == "__main__":
- main()