tensorpack.dataflow.imgaug package

This package contains Tensorpack’s augmentors. Read the tutorial first for its design and general usage.

Note that other image augmentation libraries can be wrapped into Tensorpack’s interface as well. For example, imgaug.IAAugmentor and imgaug.Albumentations wrap two popular image augmentation libraries.

class tensorpack.dataflow.imgaug.ImageAugmentor

Bases: object

Base class for an augmentor

ImageAugmentor should take images of type uint8 in range [0, 255], or floating point images in range [0, 1] or [0, 255].

rng

a numpy RandomState

augment(img)

Create a transform, and apply it to augment the input image.

This can save you one line of code, when you only care the augmentation of “one image”. It will not return the Transform object to you so you won’t be able to apply the same transformation on other data associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

img – augmented image.

augment_coords(coords, param)

augment_return_params(d)

augment_with_params(d, param)

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

reset_state()

Reset rng and other state of the augmentor.

Similar to DataFlow.reset_state(), the caller of Augmentor is responsible for calling this method (once or more times) in the process that uses the augmentor before using it.

If you use a built-in augmentation dataflow (AugmentImageComponent, etc), this method will be called in the dataflow’s own reset_state method.

If you use Python≥3.7 on Unix, this method will be automatically called after fork, and you do not need to bother calling it.

class tensorpack.dataflow.imgaug.AugmentorList(augmentors)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Augment an image by a list of augmentors

__init__(augmentors)

Parameters

augmentors (list) – list of ImageAugmentor instance to be applied.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

reset_state()

Will reset state of each augmentor

class tensorpack.dataflow.imgaug.PhotometricAugmentor

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

A base class for ImageAugmentor which only affects pixels.

Subclass should implement _get_params(img) and _impl(img, params).

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.ColorSpace(mode, keepdims=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Convert into another color space.

__init__(mode, keepdims=True)

Parameters

• mode – OpenCV color space conversion code (e.g., cv2.COLOR_BGR2HSV)

• keepdims (bool) – keep the dimension of image unchanged if OpenCV changes it.

class tensorpack.dataflow.imgaug.Grayscale(keepdims=True, rgb=False, keepshape=False)

Bases: tensorpack.dataflow.imgaug.convert.ColorSpace

Convert RGB or BGR image to grayscale.

__init__(keepdims=True, rgb=False, keepshape=False)

Parameters

• keepdims (bool) – return image of shape [H, W, 1] instead of [H, W]

• rgb (bool) – interpret input as RGB instead of the default BGR

• keepshape (bool) – whether to duplicate the gray image into 3 channels so the result has the same shape as input.

class tensorpack.dataflow.imgaug.ToUint8

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Clip and convert image to uint8. Useful to reduce communication overhead.

class tensorpack.dataflow.imgaug.ToFloat32

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Convert image to float32, may increase quality of the augmentor.

class tensorpack.dataflow.imgaug.RandomCrop(crop_shape)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Randomly crop the image into a smaller one

__init__(crop_shape)

Parameters

crop_shape – (h, w), int or a tuple of int

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.CenterCrop(crop_shape)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Crop the image at the center

__init__(crop_shape)

Parameters

crop_shape – (h, w) tuple or a int

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.RandomCropRandomShape(wmin, hmin, wmax=None, hmax=None, max_aspect_ratio=None)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random crop with a random shape

__init__(wmin, hmin, wmax=None, hmax=None, max_aspect_ratio=None)

Randomly crop a box of shape (h, w), sampled from [min, max] (both inclusive). If max is None, will use the input image shape.

Parameters

• hmin, wmax, hmax (wmin,) – range to sample shape.

• max_aspect_ratio (float) – this argument has no effect and is deprecated.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.GoogleNetRandomCropAndResize(crop_area_fraction=0.08, 1.0, aspect_ratio_range=0.75, 1.333, target_shape=224, interp=cv2.INTER_LINEAR)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

The random crop and resize augmentation proposed in Sec. 6 of “Going Deeper with Convolutions” by Google. This implementation follows the details in fb.resnet.torch.

It attempts to crop a random rectangle with 8%~100% area of the original image, and keep the aspect ratio between 3/4 to 4/3. Then it resize this crop to the target shape. If such crop cannot be found in 10 iterations, it will do a ResizeShortestEdge + CenterCrop.

__init__(crop_area_fraction=0.08, 1.0, aspect_ratio_range=0.75, 1.333, target_shape=224, interp=cv2.INTER_LINEAR)

Parameters

• crop_area_fraction (tuple(float)) – Defaults to crop 8%-100% area.

• aspect_ratio_range (tuple(float)) – Defaults to make aspect ratio in 3/4-4/3.

• target_shape (int) – Defaults to 224, the standard ImageNet image shape.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.RandomCutout(h_range, w_range, fill=0.0)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

The cutout augmentation, as described in https://arxiv.org/abs/1708.04552

__init__(h_range, w_range, fill=0.0)

Parameters

• h_range (int or tuple) – the height of rectangle to cut. If a tuple, will randomly sample from this range [low, high)

• w_range (int or tuple) – similar to above

• fill (float) – the fill value

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.IAAugmentor(augmentor)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Wrap an augmentor form the IAA library: https://github.com/aleju/imgaug. Both images and coordinates are supported.

Note

1. It’s NOT RECOMMENDED to use coordinates because the IAA library does not handle coordinates accurately.

2. Only uint8 images are supported by the IAA library.

3. The IAA library can only produces images of the same shape.

Example:

from imgaug import augmenters as iaa  # this is the aleju/imgaug library
from tensorpack import imgaug  # this is not the aleju/imgaug library
# or from dataflow import imgaug  # if you're using the standalone version of dataflow
myaug = imgaug.IAAugmentor(
    iaa.Sequential([
        iaa.Sharpen(alpha=(0, 1), lightness=(0.75, 1.5)),
        iaa.Fliplr(0.5),
        iaa.Crop(px=(0, 100)),
    ])

__init__(augmentor)

Parameters

augmentor (iaa.Augmenter) –

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Albumentations(augmentor)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Wrap an augmentor form the albumentations library: https://github.com/albu/albumentations. Coordinate augmentation is not supported by the library.

Example:

from tensorpack import imgaug
# or from dataflow import imgaug  # if you're using the standalone version of dataflow
import albumentations as AB
myaug = imgaug.Albumentations(AB.RandomRotate90(p=1))

__init__(augmentor)

Parameters

augmentor (albumentations.BasicTransform) –

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Shift(horiz_frac=0, vert_frac=0, border=cv2.BORDER_REPLICATE, border_value=0)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random horizontal and vertical shifts

__init__(horiz_frac=0, vert_frac=0, border=cv2.BORDER_REPLICATE, border_value=0)

Parameters

• horiz_frac (float) – max abs fraction for horizontal shift

• vert_frac (float) – max abs fraction for horizontal shift

• border – cv2 border method

• border_value – cv2 border value for border=cv2.BORDER_CONSTANT

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Rotation(max_deg, center_range=0, 1, interp=cv2.INTER_LINEAR, step_deg=None, border_value=0)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random rotate the image w.r.t a random center

__init__(max_deg, center_range=0, 1, interp=cv2.INTER_LINEAR, step_deg=None, border_value=0)

Parameters

• max_deg (float) – max abs value of the rotation angle (in degree).

• center_range (tuple) – (min, max) range of the random rotation center.

• interp – cv2 interpolation method

• border – cv2 border method

• step_deg (float) – if not None, the stepping of the rotation angle. The rotation angle will be a multiple of step_deg. This option requires max_deg==180 and step_deg has to be a divisor of 180)

• border_value – cv2 border value for border=cv2.BORDER_CONSTANT

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.RotationAndCropValid(max_deg, interp=cv2.INTER_LINEAR, step_deg=None)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random rotate and then crop the largest possible rectangle. Note that this will produce images of different shapes.

__init__(max_deg, interp=cv2.INTER_LINEAR, step_deg=None)

Parameters

interp, step_deg (max_deg,) – same as Rotation

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

static largest_rotated_rect(w, h, angle)

Get largest rectangle after rotation. http://stackoverflow.com/questions/16702966/rotate-image-and-crop-out-black-borders

class tensorpack.dataflow.imgaug.Affine(scale=None, translate_frac=None, rotate_max_deg=0.0, shear=0.0, interp=cv2.INTER_LINEAR, border_value=0)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random affine transform of the image w.r.t to the image center. Transformations involve:

• Translation (“move” image on the x-/y-axis)

• Rotation

• Scaling (“zoom” in/out)

• Shear (move one side of the image, turning a square into a trapezoid)

__init__(scale=None, translate_frac=None, rotate_max_deg=0.0, shear=0.0, interp=cv2.INTER_LINEAR, border_value=0)

Parameters

• scale (tuple of 2 floats) – scaling factor interval, e.g (a, b), then scale is randomly sampled from the range a <= scale <= b. Will keep original scale by default.

• translate_frac (tuple of 2 floats) – tuple of max abs fraction for horizontal and vertical translation. For example translate_frac=(a, b), then horizontal shift is randomly sampled in the range 0 < dx < img_width * a and vertical shift is randomly sampled in the range 0 < dy < img_height * b. Will not translate by default.

• shear (float) – max abs shear value in degrees between 0 to 180

• interp – cv2 interpolation method

• border – cv2 border method

• border_value – cv2 border value for border=cv2.BORDER_CONSTANT

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Hue(range=0, 180, rgb=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Randomly change color hue.

__init__(range=0, 180, rgb=True)

Parameters

• range (list or tuple) – range from which the applied hue offset is selected (maximum range can be [-90,90] for both uint8 and float32)

• rgb (bool) – whether input is RGB or BGR.

class tensorpack.dataflow.imgaug.Brightness(delta, clip=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Adjust brightness by adding a random number.

__init__(delta, clip=True)

Parameters

• delta (float) – Randomly add a value within [-delta,delta]

• clip (bool) – clip results to [0,255] even when data type is not uint8.

class tensorpack.dataflow.imgaug.BrightnessScale(range, clip=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Adjust brightness by scaling by a random factor.

__init__(range, clip=True)

Parameters

• range (tuple) – Randomly scale the image by a factor in (range[0], range[1])

• clip (bool) – clip results to [0,255] even when data type is not uint8.

class tensorpack.dataflow.imgaug.Contrast(factor_range, rgb=None, clip=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Apply x = (x - mean) * contrast_factor + mean to each channel.

__init__(factor_range, rgb=None, clip=True)

Parameters

• factor_range (list or tuple) – an interval to randomly sample the contrast_factor.

• rgb (bool or None) – if None, use the mean per-channel.

• clip (bool) – clip to [0, 255] even when data type is not uint8.

class tensorpack.dataflow.imgaug.MeanVarianceNormalize(all_channel=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Linearly scales the image to have zero mean and unit norm. x = (x - mean) / adjusted_stddev where adjusted_stddev = max(stddev, 1.0/sqrt(num_pixels * channels))

This augmentor always returns float32 images.

__init__(all_channel=True)

Parameters

all_channel (bool) – if True, normalize all channels together. else separately.

class tensorpack.dataflow.imgaug.GaussianBlur(size_range=0, 3, sigma_range=0, 0, symmetric=True, max_size=None)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Gaussian blur the image with random window size

__init__(size_range=0, 3, sigma_range=0, 0, symmetric=True, max_size=None)

Parameters

• size_range (tuple[int]) – Gaussian window size would be 2 * size + 1, where size is randomly sampled from this [low, high) range.

• sigma_range (tuple[float]) – min,max of the sigma value. 0 means opencv’s default.

• symmetric (bool) – whether to use the same size & sigma for x and y.

• max_size (int) – deprecated

class tensorpack.dataflow.imgaug.Gamma(range=- 0.5, 0.5)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Randomly adjust gamma

__init__(range=- 0.5, 0.5)

Parameters

range (list or tuple) – gamma range

class tensorpack.dataflow.imgaug.Clip(min=0, max=255)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Clip the pixel values

__init__(min=0, max=255)

Parameters

max (min,) – the clip range

class tensorpack.dataflow.imgaug.Saturation(alpha=0.4, rgb=True, clip=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Randomly adjust saturation. Follows the implementation in fb.resnet.torch.

__init__(alpha=0.4, rgb=True, clip=True)

Parameters

• alpha (float) – maximum saturation change.

• rgb (bool) – whether input is RGB or BGR.

• clip (bool) – clip results to [0,255] even when data type is not uint8.

class tensorpack.dataflow.imgaug.Lighting(std, eigval, eigvec, clip=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Lighting noise, as in the paper ImageNet Classification with Deep Convolutional Neural Networks. The implementation follows fb.resnet.torch.

__init__(std, eigval, eigvec, clip=True)

Parameters

• std (float) – maximum standard deviation

• eigval – a vector of (3,). The eigenvalues of 3 channels.

• eigvec – a 3x3 matrix. Each column is one eigen vector.

• clip (bool) – clip results to [0,255] even when data type is not uint8.

class tensorpack.dataflow.imgaug.MinMaxNormalize(min=0, max=255, all_channel=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Linearly scales the image to the range [min, max].

This augmentor always returns float32 images.

__init__(min=0, max=255, all_channel=True)

Parameters

• max (float) – The new maximum value

• min (float) – The new minimum value

• all_channel (bool) – if True, normalize all channels together. else separately.

class tensorpack.dataflow.imgaug.RandomChooseAug(aug_lists)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Randomly choose one from a list of augmentors

__init__(aug_lists)

Parameters

aug_lists (list) – list of augmentors, or list of (augmentor, probability) tuples

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

reset_state()

Reset rng and other state of the augmentor.

Similar to DataFlow.reset_state(), the caller of Augmentor is responsible for calling this method (once or more times) in the process that uses the augmentor before using it.

If you use a built-in augmentation dataflow (AugmentImageComponent, etc), this method will be called in the dataflow’s own reset_state method.

If you use Python≥3.7 on Unix, this method will be automatically called after fork, and you do not need to bother calling it.

class tensorpack.dataflow.imgaug.MapImage(func, coord_func=None)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Map the image array by simple functions.

__init__(func, coord_func=None)

Parameters

• func – a function which takes an image array and return an augmented one

• coord_func – optional. A function which takes coordinates and return augmented ones. Coordinates should be Nx2 array of (x, y)s.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Identity

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

A no-op augmentor

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.RandomApplyAug(aug, prob)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Randomly apply the augmentor with a probability. Otherwise do nothing

__init__(aug, prob)

Parameters

• aug (ImageAugmentor) – an augmentor.

• prob (float) – the probability to apply the augmentor.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

reset_state()

Reset rng and other state of the augmentor.

Similar to DataFlow.reset_state(), the caller of Augmentor is responsible for calling this method (once or more times) in the process that uses the augmentor before using it.

If you use a built-in augmentation dataflow (AugmentImageComponent, etc), this method will be called in the dataflow’s own reset_state method.

If you use Python≥3.7 on Unix, this method will be automatically called after fork, and you do not need to bother calling it.

class tensorpack.dataflow.imgaug.RandomOrderAug(aug_lists)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Apply the augmentors with randomized order.

__init__(aug_lists)

Parameters

aug_lists (list) – list of augmentors. The augmentors are assumed to not change the shape of images.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

reset_state()

Reset rng and other state of the augmentor.

Similar to DataFlow.reset_state(), the caller of Augmentor is responsible for calling this method (once or more times) in the process that uses the augmentor before using it.

If you use a built-in augmentation dataflow (AugmentImageComponent, etc), this method will be called in the dataflow’s own reset_state method.

If you use Python≥3.7 on Unix, this method will be automatically called after fork, and you do not need to bother calling it.

class tensorpack.dataflow.imgaug.Flip(horiz=False, vert=False, prob=0.5)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random flip the image either horizontally or vertically.

__init__(horiz=False, vert=False, prob=0.5)

Parameters

• horiz (bool) – use horizontal flip.

• vert (bool) – use vertical flip.

• prob (float) – probability of flip.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Resize(shape, interp=cv2.INTER_LINEAR)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Resize image to a target size

__init__(shape, interp=cv2.INTER_LINEAR)

Parameters

• shape – (h, w) tuple or a int

• interp – cv2 interpolation method

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.RandomResize(xrange, yrange=None, minimum=0, 0, aspect_ratio_thres=0.15, interp=cv2.INTER_LINEAR)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Randomly rescale width and height of the image.

__init__(xrange, yrange=None, minimum=0, 0, aspect_ratio_thres=0.15, interp=cv2.INTER_LINEAR)

Parameters

• xrange (tuple) – a (min, max) tuple. If is floating point, the tuple defines the range of scaling ratio of new width, e.g. (0.9, 1.2). If is integer, the tuple defines the range of new width in pixels, e.g. (200, 350).

• yrange (tuple) – similar to xrange, but for height. Should be None when aspect_ratio_thres==0.

• minimum (tuple) – (xmin, ymin) in pixels. To avoid scaling down too much.

• aspect_ratio_thres (float) – discard samples which change aspect ratio larger than this threshold. Set to 0 to keep aspect ratio.

• interp – cv2 interpolation method

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.ResizeShortestEdge(size, interp=cv2.INTER_LINEAR)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Resize the shortest edge to a certain number while keeping the aspect ratio.

__init__(size, interp=cv2.INTER_LINEAR)

Parameters

size (int) – the size to resize the shortest edge to.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Transpose(prob=0.5)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Random transpose the image

__init__(prob=0.5)

Parameters

prob (float) – probability of transpose.

get_transform(_)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.JpegNoise(quality_range=40, 100)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Random JPEG noise.

__init__(quality_range=40, 100)

Parameters

quality_range (tuple) – range to sample JPEG quality

class tensorpack.dataflow.imgaug.GaussianNoise(sigma=1, clip=True)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Add random Gaussian noise N(0, sigma^2) of the same shape to img.

__init__(sigma=1, clip=True)

Parameters

• sigma (float) – stddev of the Gaussian distribution.

• clip (bool) – clip the result to [0,255] in the end.

class tensorpack.dataflow.imgaug.SaltPepperNoise(white_prob=0.05, black_prob=0.05)

Bases: tensorpack.dataflow.imgaug.base.PhotometricAugmentor

Salt and pepper noise. Randomly set some elements in image to 0 or 255, regardless of its channels.

__init__(white_prob=0.05, black_prob=0.05)

Parameters

white_prob (float), black_prob (float) – probabilities setting an element to 255 or 0.

class tensorpack.dataflow.imgaug.CenterPaste(background_shape, background_filler=None)

Bases: tensorpack.dataflow.imgaug.base.ImageAugmentor

Paste the image onto the center of a background canvas.

__init__(background_shape, background_filler=None)

Parameters

• background_shape (tuple) – shape of the background canvas.

• background_filler (BackgroundFiller) – How to fill the background. Defaults to zero-filler.

get_transform(_)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.BackgroundFiller

Bases: object

Base class for all BackgroundFiller

fill(background_shape, img)

Return a proper background image of background_shape, given img.

Parameters

• background_shape (tuple) – a shape (h, w)

• img – an image

Returns

a background image

class tensorpack.dataflow.imgaug.ConstantBackgroundFiller(value)

Bases: tensorpack.dataflow.imgaug.paste.BackgroundFiller

Fill the background by a constant

__init__(value)

Parameters

value (float) – the value to fill the background.

class tensorpack.dataflow.imgaug.RandomPaste(background_shape, background_filler=None)

Bases: tensorpack.dataflow.imgaug.paste.CenterPaste

Randomly paste the image onto a background canvas.

get_transform(img)

Instantiate a Transform object to be used given the input image. Subclasses should implement this method.

The ImageAugmentor often has random policies which generate deterministic transform. Any of those random policies should happen inside this method and instantiate an actual deterministic transform to be performed. The returned Transform object should perform deterministic transforms through its apply_*() method.

In this way, the returned Transform object can be used to transform not only the input image, but other images or coordinates associated with the image.

Parameters

img (ndarray) – see notes of this class on the requirements.

Returns

Transform

class tensorpack.dataflow.imgaug.Transform

Bases: tensorpack.dataflow.imgaug.transform.BaseTransform

A deterministic image transformation, used to implement the (probably random) augmentors.

This class is also the place to provide a default implementation to any apply_xxx() method. The current default is to raise NotImplementedError in any such methods.

All subclasses should implement apply_image. The image should be of type uint8 in range [0, 255], or floating point images in range [0, 1] or [0, 255]

Some subclasses may implement apply_coords, when applicable. It should take and return a numpy array of Nx2, where each row is the (x, y) coordinate.

The implementation of each method may choose to modify its input data in-place for efficient transformation.

class tensorpack.dataflow.imgaug.ResizeTransform(h, w, new_h, new_w, interp)

Bases: tensorpack.dataflow.imgaug.transform.Transform

Resize the image.

__init__(h, w, new_h, new_w, interp)

Parameters

• w (h,) –

• new_w (new_h,) –

• interp (int) – cv2 interpolation method

apply_coords(coords)

apply_image(img)

class tensorpack.dataflow.imgaug.CropTransform(y0, x0, h, w)

Bases: tensorpack.dataflow.imgaug.transform.Transform

Crop a subimage from an image.

apply_coords(coords)

apply_image(img)

class tensorpack.dataflow.imgaug.FlipTransform(h, w, horiz=True)

Bases: tensorpack.dataflow.imgaug.transform.Transform

Flip the image.

__init__(h, w, horiz=True)

Parameters

• w (h,) –

• horiz (bool) – whether to flip horizontally or vertically.

apply_coords(coords)

apply_image(img)

class tensorpack.dataflow.imgaug.TransformList(tfms)

Bases: tensorpack.dataflow.imgaug.transform.BaseTransform

Apply a list of transforms sequentially.

__init__(tfms)

Parameters

tfms (list[Transform]) –

class tensorpack.dataflow.imgaug.TransformFactory(name=None, **kwargs)

Bases: tensorpack.dataflow.imgaug.transform.Transform

Create a Transform from user-provided functions.

__init__(name=None, **kwargs)

Parameters

• name (str, optional) – the name of this transform

• **kwargs – mapping from ‘apply_xxx’ to implementation of such functions.