Images/Annotated/util/sequence_simple.py

import imgaug as ia
from imgaug import augmenters as iaa


def get():
    def sometimes(aug): return iaa.Sometimes(0.5, aug)

    return iaa.Sequential(
        [
            iaa.CropAndPad(
                percent=(-0.1, 0.1),
                pad_mode=ia.ALL,
                pad_cval=(0, 255),
            ),
            iaa.Fliplr(0.5),  # horizontal flips
            iaa.Crop(percent=(0, 0.1)),  # random crops
            # Small gaussian blur with random sigma between 0 and 0.5.
            # But we only blur about 50% of all images.
            iaa.Sometimes(
                0.5,
                iaa.GaussianBlur(sigma=(0, 0.5))
            ),
            # Strengthen or weaken the contrast in each image.
            iaa.LinearContrast((0.75, 1.5)),
            # Add gaussian noise.
            # For 50% of all images, we sample the noise once per pixel.
            # For the other 50% of all images, we sample the noise per pixel AND
            # channel. This can change the color (not only brightness) of the
            # pixels.
            # iaa.AdditiveGaussianNoise(loc=0, scale=(
            #     0.0, 0.05*255), per_channel=0.5),
            # Make some images brighter and some darker.
            # In 20% of all cases, we sample the multiplier once per channel,
            # which can end up changing the color of the images.
            # iaa.Multiply((0.8, 1.2), per_channel=0.2),
            # Apply affine transformations to each image.
            # Scale/zoom them, translate/move them, rotate them and shear them.
            iaa.Affine(
                scale={"x": (0.8, 1.2), "y": (0.8, 1.2)},
                translate_percent={"x": (-0.2, 0.2), "y": (-0.2, 0.2)},
                rotate=(-25, 25),
                shear=(-8, 8)
            )
        ],
        random_order=False
    )