CubicSymmetry
Applies a random cubic symmetry transformation to a 3D volume.
This transform is a 3D extension of D4. While D4 handles the 8 symmetries
of a square (4 rotations x 2 reflections), CubicSymmetry handles all 48 symmetries of a cube.
Like D4, this transform does not create any interpolation artifacts as it only remaps voxels
from one position to another without any interpolation.
The 48 transformations consist of:
- 24 rotations (orientation-preserving):
* 4 rotations around each face diagonal (6 face diagonals x 4 rotations = 24)
- 24 rotoreflections (orientation-reversing):
* Reflection through a plane followed by any of the 24 rotations
For a cube, these transformations preserve:
- All face centers (6)
- All vertex positions (8)
- All edge centers (12)
works with 3D volumes and masks of the shape (D, H, W) or (D, H, W, C)
Supported Targets
keypoints
Arguments
| Name | Type | Default | Description |
|---|---|---|---|
| p | float | Probability of applying the transform. Default: 1.0 |
Image Types
uint8, float32
Notes
- This transform is particularly useful for data augmentation in 3D medical imaging,
crystallography, and voxel-based 3D modeling where the object's orientation
is arbitrary.
- All transformations preserve the object's chirality (handedness) when using
pure rotations (indices 0-23) and invert it when using rotoreflections
(indices 24-47).
Examples
>>> import numpy as np
>>> import albumentations as A
>>> volume = np.random.randint(0, 256, (10, 100, 100), dtype=np.uint8) # (D, H, W)
>>> mask3d = np.random.randint(0, 2, (10, 100, 100), dtype=np.uint8) # (D, H, W)
>>> transform = A.CubicSymmetry(p=1.0)
>>> transformed = transform(volume=volume, mask3d=mask3d)
>>> transformed_volume = transformed["volume"]
>>> transformed_mask3d = transformed["mask3d"]