model_code/data/transforms.py

import cv2
import albumentations as albu
from albumentations.pytorch import ToTensorV2


def blur_transforms(p=0.5, blur_limit=5):
    """
    Applies MotionBlur or GaussianBlur random with a probability p.
    Args:
        p (float, optional): probability. Defaults to 0.5.
        blur_limit (int, optional): Blur intensity limit. Defaults to 5.
    Returns:
        albumentation transforms: transforms.
    """
    return albu.OneOf(
        [
            albu.MotionBlur(always_apply=True),
            albu.GaussianBlur(always_apply=True),
        ],
        p=p,
    )


def color_transforms(p=0.5):
    """
    Applies RandomGamma or RandomBrightnessContrast random with a probability p.
    Args:
        p (float, optional): probability. Defaults to 0.5.
    Returns:
        albumentation transforms: transforms.
    """
    return albu.OneOf(
        [
            albu.RandomGamma(gamma_limit=(50, 150), always_apply=True),
            albu.RandomBrightnessContrast(
                brightness_limit=0.1, contrast_limit=0.2, always_apply=True
            ),
        ],
        p=p,
    )


def distortion_transforms(p=0.5):
    """
    Applies ElasticTransform with a probability p.
    Args:
        p (float, optional): probability. Defaults to 0.5.
    Returns:
        albumentation transforms: transforms.
    """
    return albu.OneOf(
        [
            albu.ElasticTransform(
                alpha=1,
                sigma=5,
                alpha_affine=10,
                border_mode=cv2.BORDER_CONSTANT,
                always_apply=True,
            )
        ],
        p=p,
    )


def get_transfos(
    augment=True,
    resize=None,
    crop=False,
    mean=0,
    std=1,
    strength=1,
    use_keypoints=False,
):
    """
    Returns transformations.

    Args:
        augment (bool, optional): Whether to apply augmentations. Defaults to True.
        resize (tuple, optional): Target image size as a tuple (height, width). Defaults to None.
        crop (bool, optional): Whether to perform center cropping. Defaults to False.
        mean (np array, optional): Mean for normalization. Defaults to 0.
        std (np array, optional): Standard deviation for normalization. Defaults to 1.
        strength (int, optional): Augmentation strength level. Defaults to 1.
        use_keypoints (bool, optional): Whether to augment keypoints. Default to False.

    Returns:
        albumentation transforms: Transforms.
    """
    if resize is None:
        resize_aug = []
    elif not crop:
        resize_aug = [albu.Resize(resize[0], resize[1])]
    else:
        resize_aug = [
            albu.Compose(
                [
                    albu.LongestMaxSize(int(resize[0] / 0.4)),
                    albu.PadIfNeeded(resize[0], resize[1], border_mode=0),
                    albu.CenterCrop(resize[0], resize[1]),
                ]
            )
        ]

    normalizer = albu.Compose(
        resize_aug
        + [
            ToTensorV2(),
        ],
        p=1,
    )

    if augment:
        if strength == 0:
            augs = [
                color_transforms(p=0.25),
            ]
        elif strength == 1:
            augs = [
                # albu.HorizontalFlip(p=0.5),
                albu.ShiftScaleRotate(
                    scale_limit=0.1,
                    shift_limit=0.0,
                    rotate_limit=10,
                    p=0.5,
                ),
                color_transforms(p=0.5),
            ]
        elif strength == 2:
            augs = [
                # albu.HorizontalFlip(p=0.5),
                albu.ShiftScaleRotate(
                    scale_limit=0.1,
                    shift_limit=0.0,
                    rotate_limit=20,
                    p=0.5,
                ),
                color_transforms(p=0.5),
            ]
        elif strength == 3:
            augs = [
                # albu.HorizontalFlip(p=0.5),
                albu.ShiftScaleRotate(
                    scale_limit=0.2,
                    shift_limit=0.0,
                    rotate_limit=30,
                    p=0.75,
                ),
                color_transforms(p=0.5),
                blur_transforms(p=0.25),
                distortion_transforms(p=0.25),
            ]
        elif strength == 4:
            augs = [
                # albu.HorizontalFlip(p=0.5),
                albu.ShiftScaleRotate(
                    scale_limit=0.0,
                    shift_limit=0.0,
                    rotate_limit=45,
                    p=0.75,
                ),
                color_transforms(p=0.25),
                blur_transforms(p=0.25),
                distortion_transforms(p=0.5),
            ]
        elif strength == 5:
            augs = [
                # albu.HorizontalFlip(p=0.5),
                albu.ShiftScaleRotate(
                    scale_limit=0.2,
                    shift_limit=0.1,
                    rotate_limit=45,
                    p=0.75,
                ),
                color_transforms(p=0.25),
                blur_transforms(p=0.25),
                distortion_transforms(p=0.5),
            ]
        elif strength == 6:
            augs = [
                albu.ShiftScaleRotate(
                    scale_limit=0.2,
                    shift_limit=0.2,
                    rotate_limit=10,
                    p=0.75,
                ),
                color_transforms(p=0.25),
                blur_transforms(p=0.25),
            ]
        elif strength == 7:
            augs = [
                # albu.HorizontalFlip(p=0.5),
                albu.VerticalFlip(p=0.5),
                albu.ShiftScaleRotate(
                    scale_limit=0.2,
                    shift_limit=0.1,
                    rotate_limit=45,
                    p=0.75,
                ),
                color_transforms(p=0.25),
                blur_transforms(p=0.25),
                distortion_transforms(p=0.5),
            ]
    else:
        augs = []

    keypoint_params = (
        albu.KeypointParams(format="xy", remove_invisible=False)
        if use_keypoints
        else None
    )

    return albu.Compose(augs + [normalizer], keypoint_params=keypoint_params)