Random horizontal and vertical flips doesn't work with bbox

🐛 Bug

Random{Horizontal/Vertical}Flip for Transform2D and Transform3D doesn’t work. See image attached.

EDIT: RandomRotation always shows the same behavior. RandomCrop, CenterCrop, RandomResizedCrop, RandomErasing and RandomPerspective are fine (checked 2D version).

To Reproduce

!wget https://tinypng.com/images/social/website.jpg -O panda.jpg

from kornia import augmentation as K

tfm= K.AugmentationSequential(
    K.RandomVerticalFlip(p=1.)
    data_keys=["input", "bbox"]),
    return_transform=False,
    same_on_batch=False
)


img = cv2.imread("panda.jpg", cv2.IMREAD_COLOR)
img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
h, w = img.shape[:2]

image= image_to_tensor(img).float() / 255.

bbox = torch.tensor([[[355,10],[660,10],[660,250],[355,250]]])
tfm(image, bbox.float())

Original image:

Transformed image:

Original box (in xyxy): tensor([[355., 10., 660., 250.]]) Transformed box (in xyxy): tensor([[ 355., -246., 660., -6.]])

Expected behavior

Correct transformed box (in xyxy): tensor([[355., 260., 660., 500.]])

Environment

pytorch 1.8.1 Kornia 0.5.6

Addition comments

Shortly, I’ll make a PR

[edgarriba]

@hal-314 please, make sure to add some tests in PR that fixes the issue

[edgarriba]

@shijianjian