Function differences with torch.torchvision.datasets.CocoDetection
torchvision.datasets.CocoDetection
class torchvision.datasets.CocoDetection(
root: str,
annFile: str,
transform: Optional[Callable]=None,
target_transform: Optional[Callable]=None,
transforms: Optional[Callable]=None
)
For more information, see torchvision.datasets.CocoDetection.
mindspore.dataset.CocoDataset
class mindspore.dataset.CocoDataset(
dataset_dir,
annotation_file,
task="Detection",
num_samples=None,
num_parallel_workers=None,
shuffle=None,
decode=False,
sampler=None,
num_shards=None,
shard_id=None,
cache=None,
extra_metadata=False
)
For more information, see mindspore.dataset.CocoDataset.
Differences
PyTorch: Enter the COCO dataset, return the transformed version with standard interfaces.
MindSpore: Enter the COCO dataset, return the transformed version for four kinds of tasks with standard interfaces.
Code Example
import mindspore.dataset as ds
import torchvision.datasets as datasets
import torchvision.transforms as T
# In MindSpore, CocoDataset supports four kinds of tasks, which are Object Detection, Keypoint Detection, Stuff Segmentation and Panoptic Segmentation of 2017 Train/Val/Test dataset.
coco_dataset_dir = "/path/to/coco_dataset_directory/images"
coco_annotation_file = "/path/to/coco_dataset_directory/annotation_file"
# Read COCO data for Detection task. Output columns: [image, dtype=uint8], [bbox, dtype=float32], [category_id, dtype=uint32], [iscrowd, dtype=uint32]
dataset = ds.CocoDataset(
dataset_dir=coco_dataset_dir,
annotation_file=coco_annotation_file,
task='Detection',
decode=True,
shuffle=False,
extra_metadata=True)
dataset = dataset.rename("_meta-filename", "filename")
file_name = []
bbox = []
category_id = []
iscrowd = []
for data in dataset.create_dict_iterator(num_epochs=1, output_numpy=True):
file_name.append(data["filename"])
bbox.append(data["bbox"])
category_id.append(data["category_id"])
iscrowd.append(data["iscrowd"])
print(file_name[0])
print(bbox[0])
print(category_id[0])
print(iscrowd[0])
# out:
# 000000391895
# [[10. 10. 10. 10.]
# [70. 70. 70. 70.]]
# [[1]
# [7]]
# [[0]
# [0]]
# In torch, the output will be result of transform, eg. Tensor
root = "/path/to/coco_dataset_directory/images"
annFile = "/path/to/coco_dataset_directory/annotation_file"
# Convert a PIL Image or numpy.ndarray to tensor.
dataset = datasets.CocoDetection(root, annFile, transform=T.ToTensor())
for item in dataset:
print("item:", item[0])
break
# out:
# loading annotations into memory...
# Done (t=0.00s)
# creating index...
# index created!
# item: tensor([[[0.8588, 0.8549, 0.8549, ..., 0.7529, 0.7529, 0.7529,
# [0.8549, 0.8549, 0.8510, ..., 0.7529, 0.7529, 0.7529],
# [0.8549, 0.8510, 0.8510, ..., 0.7529, 0.7529, 0.7529],
# ...,
#
# ...,
# [0.8471, 0.8510, 0.8549, ..., 0.7412, 0.7333, 0.7294],
# [0.8549, 0.8549, 0.8549, ..., 0.7412, 0.7333, 0.7294],
# [0.8627, 0.8627, 0.8549, ..., 0.7412, 0.7333, 0.7294]]])