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# Copyright (c) Facebook, Inc. and its affiliates. | |
import copy | |
import logging | |
import numpy as np | |
from typing import List, Optional, Union | |
import torch | |
from detectron2.config import configurable | |
from . import detection_utils as utils | |
from . import transforms as T | |
""" | |
This file contains the default mapping that's applied to "dataset dicts". | |
""" | |
__all__ = ["DatasetMapper"] | |
class DatasetMapper: | |
""" | |
A callable which takes a dataset dict in Detectron2 Dataset format, | |
and map it into a format used by the model. | |
This is the default callable to be used to map your dataset dict into training data. | |
You may need to follow it to implement your own one for customized logic, | |
such as a different way to read or transform images. | |
See :doc:`/tutorials/data_loading` for details. | |
The callable currently does the following: | |
1. Read the image from "file_name" | |
2. Applies cropping/geometric transforms to the image and annotations | |
3. Prepare data and annotations to Tensor and :class:`Instances` | |
""" | |
def __init__( | |
self, | |
is_train: bool, | |
*, | |
augmentations: List[Union[T.Augmentation, T.Transform]], | |
image_format: str, | |
use_instance_mask: bool = False, | |
use_keypoint: bool = False, | |
instance_mask_format: str = "polygon", | |
keypoint_hflip_indices: Optional[np.ndarray] = None, | |
precomputed_proposal_topk: Optional[int] = None, | |
recompute_boxes: bool = False, | |
): | |
""" | |
NOTE: this interface is experimental. | |
Args: | |
is_train: whether it's used in training or inference | |
augmentations: a list of augmentations or deterministic transforms to apply | |
image_format: an image format supported by :func:`detection_utils.read_image`. | |
use_instance_mask: whether to process instance segmentation annotations, if available | |
use_keypoint: whether to process keypoint annotations if available | |
instance_mask_format: one of "polygon" or "bitmask". Process instance segmentation | |
masks into this format. | |
keypoint_hflip_indices: see :func:`detection_utils.create_keypoint_hflip_indices` | |
precomputed_proposal_topk: if given, will load pre-computed | |
proposals from dataset_dict and keep the top k proposals for each image. | |
recompute_boxes: whether to overwrite bounding box annotations | |
by computing tight bounding boxes from instance mask annotations. | |
""" | |
if recompute_boxes: | |
assert use_instance_mask, "recompute_boxes requires instance masks" | |
# fmt: off | |
self.is_train = is_train | |
self.augmentations = T.AugmentationList(augmentations) | |
self.image_format = image_format | |
self.use_instance_mask = use_instance_mask | |
self.instance_mask_format = instance_mask_format | |
self.use_keypoint = use_keypoint | |
self.keypoint_hflip_indices = keypoint_hflip_indices | |
self.proposal_topk = precomputed_proposal_topk | |
self.recompute_boxes = recompute_boxes | |
# fmt: on | |
logger = logging.getLogger(__name__) | |
mode = "training" if is_train else "inference" | |
logger.info(f"[DatasetMapper] Augmentations used in {mode}: {augmentations}") | |
def from_config(cls, cfg, is_train: bool = True): | |
augs = utils.build_augmentation(cfg, is_train) | |
if cfg.INPUT.CROP.ENABLED and is_train: | |
augs.insert(0, T.RandomCrop(cfg.INPUT.CROP.TYPE, cfg.INPUT.CROP.SIZE)) | |
recompute_boxes = cfg.MODEL.MASK_ON | |
else: | |
recompute_boxes = False | |
ret = { | |
"is_train": is_train, | |
"augmentations": augs, | |
"image_format": cfg.INPUT.FORMAT, | |
"use_instance_mask": cfg.MODEL.MASK_ON, | |
"instance_mask_format": cfg.INPUT.MASK_FORMAT, | |
"use_keypoint": cfg.MODEL.KEYPOINT_ON, | |
"recompute_boxes": recompute_boxes, | |
} | |
if cfg.MODEL.KEYPOINT_ON: | |
ret["keypoint_hflip_indices"] = utils.create_keypoint_hflip_indices(cfg.DATASETS.TRAIN) | |
if cfg.MODEL.LOAD_PROPOSALS: | |
ret["precomputed_proposal_topk"] = ( | |
cfg.DATASETS.PRECOMPUTED_PROPOSAL_TOPK_TRAIN | |
if is_train | |
else cfg.DATASETS.PRECOMPUTED_PROPOSAL_TOPK_TEST | |
) | |
return ret | |
def _transform_annotations(self, dataset_dict, transforms, image_shape): | |
# USER: Modify this if you want to keep them for some reason. | |
for anno in dataset_dict["annotations"]: | |
if not self.use_instance_mask: | |
anno.pop("segmentation", None) | |
if not self.use_keypoint: | |
anno.pop("keypoints", None) | |
# USER: Implement additional transformations if you have other types of data | |
annos = [ | |
utils.transform_instance_annotations( | |
obj, transforms, image_shape, keypoint_hflip_indices=self.keypoint_hflip_indices | |
) | |
for obj in dataset_dict.pop("annotations") | |
if obj.get("iscrowd", 0) == 0 | |
] | |
instances = utils.annotations_to_instances( | |
annos, image_shape, mask_format=self.instance_mask_format | |
) | |
# After transforms such as cropping are applied, the bounding box may no longer | |
# tightly bound the object. As an example, imagine a triangle object | |
# [(0,0), (2,0), (0,2)] cropped by a box [(1,0),(2,2)] (XYXY format). The tight | |
# bounding box of the cropped triangle should be [(1,0),(2,1)], which is not equal to | |
# the intersection of original bounding box and the cropping box. | |
if self.recompute_boxes: | |
instances.gt_boxes = instances.gt_masks.get_bounding_boxes() | |
dataset_dict["instances"] = utils.filter_empty_instances(instances) | |
def __call__(self, dataset_dict): | |
""" | |
Args: | |
dataset_dict (dict): Metadata of one image, in Detectron2 Dataset format. | |
Returns: | |
dict: a format that builtin models in detectron2 accept | |
""" | |
dataset_dict = copy.deepcopy(dataset_dict) # it will be modified by code below | |
# USER: Write your own image loading if it's not from a file | |
image = utils.read_image(dataset_dict["file_name"], format=self.image_format) | |
utils.check_image_size(dataset_dict, image) | |
# USER: Remove if you don't do semantic/panoptic segmentation. | |
if "sem_seg_file_name" in dataset_dict: | |
sem_seg_gt = utils.read_image(dataset_dict.pop("sem_seg_file_name"), "L").squeeze(2) | |
else: | |
sem_seg_gt = None | |
aug_input = T.AugInput(image, sem_seg=sem_seg_gt) | |
transforms = self.augmentations(aug_input) | |
image, sem_seg_gt = aug_input.image, aug_input.sem_seg | |
image_shape = image.shape[:2] # h, w | |
# Pytorch's dataloader is efficient on torch.Tensor due to shared-memory, | |
# but not efficient on large generic data structures due to the use of pickle & mp.Queue. | |
# Therefore it's important to use torch.Tensor. | |
dataset_dict["image"] = torch.as_tensor(np.ascontiguousarray(image.transpose(2, 0, 1))) | |
if sem_seg_gt is not None: | |
dataset_dict["sem_seg"] = torch.as_tensor(sem_seg_gt.astype("long")) | |
# USER: Remove if you don't use pre-computed proposals. | |
# Most users would not need this feature. | |
if self.proposal_topk is not None: | |
utils.transform_proposals( | |
dataset_dict, image_shape, transforms, proposal_topk=self.proposal_topk | |
) | |
if not self.is_train: | |
# USER: Modify this if you want to keep them for some reason. | |
dataset_dict.pop("annotations", None) | |
dataset_dict.pop("sem_seg_file_name", None) | |
return dataset_dict | |
if "annotations" in dataset_dict: | |
self._transform_annotations(dataset_dict, transforms, image_shape) | |
return dataset_dict | |