AutoEval / doctr /datasets /detection.py
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# Copyright (C) 2021-2024, Mindee.
# This program is licensed under the Apache License 2.0.
# See LICENSE or go to <https://opensource.org/licenses/Apache-2.0> for full license details.
import json
import os
from typing import Any, Dict, List, Tuple, Type, Union
import numpy as np
from doctr.file_utils import CLASS_NAME
from .datasets import AbstractDataset
from .utils import pre_transform_multiclass
__all__ = ["DetectionDataset"]
class DetectionDataset(AbstractDataset):
"""Implements a text detection dataset
>>> from doctr.datasets import DetectionDataset
>>> train_set = DetectionDataset(img_folder="/path/to/images",
>>> label_path="/path/to/labels.json")
>>> img, target = train_set[0]
Args:
----
img_folder: folder with all the images of the dataset
label_path: path to the annotations of each image
use_polygons: whether polygons should be considered as rotated bounding box (instead of straight ones)
**kwargs: keyword arguments from `AbstractDataset`.
"""
def __init__(
self,
img_folder: str,
label_path: str,
use_polygons: bool = False,
**kwargs: Any,
) -> None:
super().__init__(
img_folder,
pre_transforms=pre_transform_multiclass,
**kwargs,
)
# File existence check
self._class_names: List = []
if not os.path.exists(label_path):
raise FileNotFoundError(f"unable to locate {label_path}")
with open(label_path, "rb") as f:
labels = json.load(f)
self.data: List[Tuple[str, Tuple[np.ndarray, List[str]]]] = []
np_dtype = np.float32
for img_name, label in labels.items():
# File existence check
if not os.path.exists(os.path.join(self.root, img_name)):
raise FileNotFoundError(f"unable to locate {os.path.join(self.root, img_name)}")
geoms, polygons_classes = self.format_polygons(label["polygons"], use_polygons, np_dtype)
self.data.append((img_name, (np.asarray(geoms, dtype=np_dtype), polygons_classes)))
def format_polygons(
self, polygons: Union[List, Dict], use_polygons: bool, np_dtype: Type
) -> Tuple[np.ndarray, List[str]]:
"""Format polygons into an array
Args:
----
polygons: the bounding boxes
use_polygons: whether polygons should be considered as rotated bounding box (instead of straight ones)
np_dtype: dtype of array
Returns:
-------
geoms: bounding boxes as np array
polygons_classes: list of classes for each bounding box
"""
if isinstance(polygons, list):
self._class_names += [CLASS_NAME]
polygons_classes = [CLASS_NAME for _ in polygons]
_polygons: np.ndarray = np.asarray(polygons, dtype=np_dtype)
elif isinstance(polygons, dict):
self._class_names += list(polygons.keys())
polygons_classes = [k for k, v in polygons.items() for _ in v]
_polygons = np.concatenate([np.asarray(poly, dtype=np_dtype) for poly in polygons.values() if poly], axis=0)
else:
raise TypeError(f"polygons should be a dictionary or list, it was {type(polygons)}")
geoms = _polygons if use_polygons else np.concatenate((_polygons.min(axis=1), _polygons.max(axis=1)), axis=1)
return geoms, polygons_classes
@property
def class_names(self):
return sorted(set(self._class_names))