oneflow.image

Image processing

oneflow.image.CropMirrorNormalize(input_blob: oneflow_api.BlobDesc, mirror_blob: Optional[oneflow_api.BlobDesc] = None, color_space: str = 'BGR', output_layout: str = 'NCHW', crop_h: int = 0, crop_w: int = 0, crop_pos_y: float = 0.5, crop_pos_x: float = 0.5, mean: Sequence[float] = [0.0], std: Sequence[float] = [1.0], output_dtype: oneflow.python.framework.dtype.dtype = <class 'oneflow.python.framework.dtype.float32'>, name: Optional[str] = None) → oneflow_api.BlobDesc

This operator performs the cropping, normalization, and horizontal flip for input Blob.

If crop_h and crop_w are provided, the image cropping position is specified by “crop_pos_y” and “crop_pos_x”.

The position is computed as follows:

\[ \begin{align}\begin{aligned}& crop_x = crop\_pos\_x*(Width-crop\_w)\\& crop_y = crop\_pos\_y*(Height-crop\_h)\end{aligned}\end{align} \]

The Width and Height is the width and height of input Blob.

Parameters

• input_blob (oneflow_api.BlobDesc) – The input Blob.

• mirror_blob (Optional[oneflow_api.BlobDesc], optional) – The operation for horizontal flip, if it is None, the operator will not perform the horizontal flip. Defaults to None.

• color_space (str, optional) – The color space for input Blob. Defaults to “BGR”.

• output_layout (str, optional) – The output format. Defaults to “NCHW”.

• crop_h (int, optional) – The image cropping window height. Defaults to 0.

• crop_w (int, optional) – The image cropping window width. Defaults to 0.

• crop_pos_y (float, optional) – The vertical position of the image cropping window, the value range is normalized to (0.0, 1.0). Defaults to 0.5.

• crop_pos_x (float, optional) – The horizontal position of the image cropping window, the value range is normalized to (0.0, 1.0). Defaults to 0.5.

• mean (Sequence[float], optional) – The mean value for normalization. Defaults to [0.0].

• std (Sequence[float], optional) – The standard deviation values for normalization. Defaults to [1.0].

• output_dtype (dtype_util.dtype, optional) – The datatype of output Blob. Defaults to dtype_util.float.

• name (Optional[str], optional) – The name for the operation. Defaults to None.

Raises

NotImplementedError – The data type of input Blob should be tensor_buffer or uint8

Returns

The result Blob

Return type

oneflow_api.BlobDesc

For example:

import oneflow as flow
import oneflow.typing as tp
from typing import Tuple


@flow.global_function(type="predict")
def crop_mirror_job() -> Tuple[tp.Numpy, tp.Numpy]:
    batch_size = 1
    color_space = "RGB"
    # our ofrecord file path is "./dataset/part-0"
    ofrecord = flow.data.ofrecord_reader(
        "./imgdataset",
        batch_size=batch_size,
        data_part_num=1,
        part_name_suffix_length=-1,
        part_name_prefix='part-',
        shuffle_after_epoch=True,
    )
    image = flow.data.OFRecordImageDecoder(
            ofrecord, "encoded", color_space=color_space
        )
    res_image, scale, new_size = flow.image.Resize(
            image, target_size=(512, 512)
        )
    label = flow.data.OFRecordRawDecoder(
        ofrecord, "class/label", shape=(1, ), dtype=flow.int32
    )
    rng = flow.random.CoinFlip(batch_size=batch_size)
    normal = flow.image.CropMirrorNormalize(
            res_image,
            mirror_blob=rng,
            color_space=color_space,
            crop_h= 256,
            crop_w= 256,
            crop_pos_y=0.5,
            crop_pos_x=0.5,
            mean=[123.68, 116.779, 103.939],
            std=[58.393, 57.12, 57.375],
            output_dtype=flow.float,
        )

    return normal, label

if __name__ == "__main__":
    images, labels = crop_mirror_job()
    # images.shape (1, 3, 256, 256)

oneflow.image.Resize(image: oneflow_api.BlobDesc, target_size: Union[int, Sequence[int]] = None, min_size: Optional[int] = None, max_size: Optional[int] = None, keep_aspect_ratio: bool = False, resize_side: str = 'shorter', channels: int = 3, dtype: Optional[oneflow.python.framework.dtype.dtype] = None, interpolation_type: str = 'auto', name: Optional[str] = None, color_space: Optional[str] = None, interp_type: Optional[str] = None, resize_shorter: int = 0, resize_x: int = 0, resize_y: int = 0) → Union[oneflow_api.BlobDesc, Sequence[oneflow_api.BlobDesc]]

Resize images to target size.

Parameters

• image – A Tensor consists of images to be resized.

• target_size – A list or tuple when keep_aspect_ratio is false or an int when keep_aspect_ratio is true. When keep_aspect_ratio is false, target_size has a form of (target_width, target_height) that image will resize to. When keep_aspect_ratio is true, the longer side or shorter side of the image will be resized to target size.

• min_size – An int, optional. Only works when keep_aspect_ratio is true and resize_side is “longer”. If min_size is not None, the shorter side must be greater than or equal to min_size. Default is None.

• max_size – An int, optional. Only works when keep_aspect_ratio is true and resize_side is “shorter”. If max_size is not None, the longer side must be less than or equal to max_size. Default is None.

• keep_aspect_ratio – A bool. If is false, indicate that image will be resized to fixed width and height, otherwise image will be resized keeping aspect ratio.

• resize_side – A str of “longer” or “shorter”. Only works when keep_aspect_ratio is True. If resize_side is “longer”, the longer side of image will be resized to target_size. If resize_side is “shorter”, the shorter side of image will be resized to target_size.

• channels – An int. how many channels an image has

• dtype – oneflow.dtype. Indicate output resized image data type.

• interpolation_type – A str of “auto”, “bilinear”, “nearest_neighbor”, “bicubic” or “area”. Indicate interpolation method used to resize image.

• name – A str, optional. Name for the operation.

• color_space – Deprecated, a str of “RGB”, “BGR” or “GRAY”. Please use channels instead.

• interp_type – Deprecated, s str of “Linear”, “Cubic” or “NN”. Please use interpolation_type instead.

• resize_shorter – Deprecated, a int. Indicate target size that the shorter side of image will resize to. Please use target_size and resize_side instead.

• resize_x – Deprecated, a int. Indicate the target size that the width of image will resize to. Please use target_size instead.

• resize_y – Deprecated, a int. Indicate the target size that the height of image will resize to. Please use target_size instead.

Returns

Tuple of resized images Blob, width and height scales Blob and new width and height Blob (new width and height Blob will be None when keep_aspect_ratio is false). If deprecated params are used, a single resized images Blob will be returned.

For example:

import oneflow as flow
import oneflow.typing as tp
from typing import Tuple


@flow.global_function(type="predict")
def ofrecord_reader_job() -> Tuple[tp.Numpy, tp.Numpy]:
    batch_size = 16
    color_space = "RGB"
    # our ofrecord file path is "./dataset/part-0"
    ofrecord = flow.data.ofrecord_reader(
        "./imgdataset",
        batch_size=batch_size,
        data_part_num=1,
        part_name_suffix_length=-1,
        part_name_prefix='part-',
        random_shuffle=True,
        shuffle_after_epoch=True,
    )
    image = flow.data.OFRecordImageDecoderRandomCrop(
            ofrecord, "encoded", color_space=color_space
        )
    res_image, scale, new_size = flow.image.Resize(
            image, target_size=(224, 224)
        )
    label = flow.data.OFRecordRawDecoder(
        ofrecord, "class/label", shape=(1, ), dtype=flow.int32
    )

    return res_image, label

if __name__ == "__main__":
    images, labels = ofrecord_reader_job()
    # image.shape (16, 224, 224, 3)

oneflow.image.batch_align(images: oneflow_api.BlobDesc, shape: Sequence[int], dtype: oneflow.python.framework.dtype.dtype, alignment: int, name: Optional[str] = None) → oneflow_api.BlobDesc

This operator aligns the shape for a batch of images.

The aligned shape is computed as:

\[ \begin{align}\begin{aligned}& shape_{width} = int(\frac{(shape_{width}+alignment-1)}{alignment})*alignment\\& shape_{height} = int(\frac{(shape_{height}+alignment-1)}{alignment})*alignment\end{aligned}\end{align} \]

Parameters

• images (oneflow_api.BlobDesc) – The images.

• shape (Sequence[int]) – The maximum static shape of input images.

• dtype (dtype_util.dtype) – The data type.

• alignment (int) – The align factor.

• name (Optional[str], optional) – The name for the operation. Defaults to None.

Returns

The result Blob

Return type

oneflow_api.BlobDesc

For example:

import cv2
import numpy as np
import oneflow as flow
import oneflow.typing as tp


def _of_image_batch_align(images, input_shape, output_shape, alignment):
    func_config = flow.FunctionConfig()
    func_config.default_data_type(flow.float)
    func_config.default_logical_view(flow.scope.mirrored_view())

    @flow.global_function(function_config=func_config)
    def image_batch_align_job(
        images_def: tp.ListListNumpy.Placeholder(shape=input_shape, dtype=flow.float)
    ) -> tp.ListNumpy:
        # Convert to tensor buffer
        images_buffer = flow.tensor_list_to_tensor_buffer(images_def)
        image = flow.image_batch_align(
            images_buffer, shape=output_shape[1:], dtype=flow.float, alignment=alignment
        )
        return image

    image = image_batch_align_job([images])
    return image[0]


def _read_images_by_cv(image_files):
    images = [cv2.imread(image_file).astype(np.single) for image_file in image_files]
    return [np.expand_dims(image, axis=0) for image in images]


def _get_images_static_shape(images):
    image_shapes = [image.shape for image in images]
    image_static_shape = np.amax(image_shapes, axis=0)
    assert isinstance(
        image_static_shape, np.ndarray
    ), "image_shapes: {}, image_static_shape: {}".format(
        str(image_shapes), str(image_static_shape)
    )
    image_static_shape = image_static_shape.tolist()
    assert image_static_shape[0] == 1, str(image_static_shape)
    image_static_shape[0] = len(image_shapes)
    return image_static_shape

def _roundup(x, n):
    # compute the aligned shape
    return int((x + n - 1) / n) * n

if __name__ == "__main__":
    img = _read_images_by_cv(['./img/1.jpg', './img/2.jpg', './img/3.jpg'])
    img_shape = _get_images_static_shape(img) # In example is [3, 349, 367, 3]
    alignment = 16 # alignment factor
    aligned_image_shape = [
        img_shape[0],
        _roundup(img_shape[1], alignment),
        _roundup(img_shape[2], alignment),
        img_shape[3],
    ]
    image = _of_image_batch_align(img, tuple(img_shape), aligned_image_shape, alignment)

oneflow.image.crop_mirror_normalize(input_blob: oneflow_api.BlobDesc, mirror_blob: Optional[oneflow_api.BlobDesc] = None, color_space: str = 'BGR', output_layout: str = 'NCHW', crop_h: int = 0, crop_w: int = 0, crop_pos_y: float = 0.5, crop_pos_x: float = 0.5, mean: Sequence[float] = [0.0], std: Sequence[float] = [1.0], output_dtype: oneflow.python.framework.dtype.dtype = <class 'oneflow.python.framework.dtype.float32'>, name: Optional[str] = None) → oneflow_api.BlobDesc

This operator performs the cropping, normalization, and horizontal flip for input Blob.

If crop_h and crop_w are provided, the image cropping position is specified by “crop_pos_y” and “crop_pos_x”.

The position is computed as follows:

\[ \begin{align}\begin{aligned}& crop_x = crop\_pos\_x*(Width-crop\_w)\\& crop_y = crop\_pos\_y*(Height-crop\_h)\end{aligned}\end{align} \]

The Width and Height is the width and height of input Blob.

Parameters

• input_blob (oneflow_api.BlobDesc) – The input Blob.

• mirror_blob (Optional[oneflow_api.BlobDesc], optional) – The operation for horizontal flip, if it is None, the operator will not perform the horizontal flip. Defaults to None.

• color_space (str, optional) – The color space for input Blob. Defaults to “BGR”.

• output_layout (str, optional) – The output format. Defaults to “NCHW”.

• crop_h (int, optional) – The image cropping window height. Defaults to 0.

• crop_w (int, optional) – The image cropping window width. Defaults to 0.

• crop_pos_y (float, optional) – The vertical position of the image cropping window, the value range is normalized to (0.0, 1.0). Defaults to 0.5.

• crop_pos_x (float, optional) – The horizontal position of the image cropping window, the value range is normalized to (0.0, 1.0). Defaults to 0.5.

• mean (Sequence[float], optional) – The mean value for normalization. Defaults to [0.0].

• std (Sequence[float], optional) – The standard deviation values for normalization. Defaults to [1.0].

• output_dtype (dtype_util.dtype, optional) – The datatype of output Blob. Defaults to dtype_util.float.

• name (Optional[str], optional) – The name for the operation. Defaults to None.

Raises

NotImplementedError – The data type of input Blob should be tensor_buffer or uint8

Returns

The result Blob

Return type

oneflow_api.BlobDesc

For example:

import oneflow as flow
import oneflow.typing as tp
from typing import Tuple


@flow.global_function(type="predict")
def crop_mirror_job() -> Tuple[tp.Numpy, tp.Numpy]:
    batch_size = 1
    color_space = "RGB"
    # our ofrecord file path is "./dataset/part-0"
    ofrecord = flow.data.ofrecord_reader(
        "./imgdataset",
        batch_size=batch_size,
        data_part_num=1,
        part_name_suffix_length=-1,
        part_name_prefix='part-',
        shuffle_after_epoch=True,
    )
    image = flow.data.OFRecordImageDecoder(
            ofrecord, "encoded", color_space=color_space
        )
    res_image, scale, new_size = flow.image.Resize(
            image, target_size=(512, 512)
        )
    label = flow.data.OFRecordRawDecoder(
        ofrecord, "class/label", shape=(1, ), dtype=flow.int32
    )
    rng = flow.random.CoinFlip(batch_size=batch_size)
    normal = flow.image.CropMirrorNormalize(
            res_image,
            mirror_blob=rng,
            color_space=color_space,
            crop_h= 256,
            crop_w= 256,
            crop_pos_y=0.5,
            crop_pos_x=0.5,
            mean=[123.68, 116.779, 103.939],
            std=[58.393, 57.12, 57.375],
            output_dtype=flow.float,
        )

    return normal, label

if __name__ == "__main__":
    images, labels = crop_mirror_job()
    # images.shape (1, 3, 256, 256)

oneflow.image.decode(images_bytes_buffer: oneflow_api.BlobDesc, dtype: oneflow.python.framework.dtype.dtype = <class 'oneflow.python.framework.dtype.uint8'>, color_space: str = 'BGR', name: Optional[str] = None) → oneflow_api.BlobDesc

This operator decode the image.

Parameters

• images_bytes_buffer (oneflow_api.BlobDesc) – The input Blob. Its type should be kTensorBuffer. More details please refer to the code example.

• dtype (dtype_util.dtype, optional) – The data type. Defaults to dtype_util.uint8.

• color_space (str, optional) – The color space. Defaults to “BGR”.

• name (Optional[str], optional) – The name for the opreation. Defaults to None.

Returns

The decoded image list.

Return type

oneflow_api.BlobDesc

For example:

import oneflow as flow
import oneflow.typing as tp
import numpy as np
from PIL import Image


def _of_image_decode(images):
    image_files = [open(im, "rb") for im in images]
    images_bytes = [imf.read() for imf in image_files]
    static_shape = (len(images_bytes), max([len(bys) for bys in images_bytes]))
    for imf in image_files:
        imf.close()

    func_config = flow.FunctionConfig()
    func_config.default_data_type(flow.float)
    func_config.default_logical_view(flow.scope.mirrored_view())

    @flow.global_function(function_config=func_config)
    def image_decode_job(
        images_def: tp.ListListNumpy.Placeholder(shape=static_shape, dtype=flow.int8)
    )->tp.ListListNumpy:
        # convert to tensor buffer
        images_buffer = flow.tensor_list_to_tensor_buffer(images_def)
        decoded_images_buffer = flow.image_decode(images_buffer)
        # Remember to set a shape
        # convert back to tensor list
        return flow.tensor_buffer_to_tensor_list(
            decoded_images_buffer, shape=(640, 640, 3), dtype=flow.uint8
        )

    images_np_arr = [
        np.frombuffer(bys, dtype=np.byte).reshape(1, -1) for bys in images_bytes
    ]
    decoded_images = image_decode_job([images_np_arr])
    return decoded_images[0]


if __name__ == "__main__":
    img = _of_image_decode(['./img/1.jpg'])
    print(img[0].shape) # Our image shape is (1, 349, 367, 3)

oneflow.image.flip(image: oneflow_api.BlobDesc, flip_code: Union[int, oneflow_api.BlobDesc], name: Optional[str] = None) → oneflow_api.BlobDesc

This operator flips the images.

The flip code corresponds to the different flip mode:

0 (0x00): Non Flip

1 (0x01): Horizontal Flip

16 (0x10): Vertical Flip

17 (0x11): Both Horizontal and Vertical Flip

Parameters

• image (oneflow_api.BlobDesc) – The input images.

• flip_code (Union[int, oneflow_api.BlobDesc]) – The flip code.

• name (Optional[str], optional) – The name for the operation. Defaults to None.

Returns

The result Blob

Return type

oneflow_api.BlobDesc

For example:

import cv2
import numpy as np
import oneflow as flow
import oneflow.typing as tp


def _of_image_flip(images, image_shape, flip_code):
    func_config = flow.FunctionConfig()
    func_config.default_data_type(flow.float)
    func_config.default_logical_view(flow.scope.mirrored_view())

    @flow.global_function(function_config=func_config)
    def image_flip_job(
        images_def: tp.ListListNumpy.Placeholder(shape=image_shape, dtype=flow.float)
    ) -> tp.ListListNumpy:
        images_buffer = flow.tensor_list_to_tensor_buffer(images_def)
        flip_images = flow.image_flip(images_buffer, flip_code)
        return flow.tensor_buffer_to_tensor_list(
            flip_images, shape=image_shape[1:], dtype=flow.float
        )

    image_tensor = image_flip_job([images])
    return image_tensor[0]


def _read_images_by_cv(image_files):
    images = [cv2.imread(image_file).astype(np.single) for image_file in image_files]
    return [np.expand_dims(image, axis=0) for image in images]


def _get_images_static_shape(images):
    image_shapes = [image.shape for image in images]
    image_static_shape = np.amax(image_shapes, axis=0)
    assert isinstance(
        image_static_shape, np.ndarray
    ), "image_shapes: {}, image_static_shape: {}".format(
        str(image_shapes), str(image_static_shape)
    )
    image_static_shape = image_static_shape.tolist()
    assert image_static_shape[0] == 1, str(image_static_shape)
    image_static_shape[0] = len(image_shapes)
    return image_static_shape

if __name__ == "__main__":
    img = _read_images_by_cv(['./img/1.jpg', './img/2.jpg', './img/3.jpg'])
    img_shape = _get_images_static_shape(img) # In example is [3, 349, 367, 3]
    image = _of_image_flip(img,
                   tuple(img_shape),
                   flip_code=1)

oneflow.image.normalize(image: oneflow_api.BlobDesc, std: Sequence[float], mean: Sequence[float], name: Optional[str] = None) → oneflow_api.BlobDesc

This operator normalizes the image.

Parameters

• image (oneflow_api.BlobDesc) – The input image.

• std (Sequence[float]) – The standard deviation of the images.

• mean (Sequence[float]) – The mean value of the images.

• name (Optional[str], optional) – The name for the operation. Defaults to None.

Returns

The result Blob

Return type

oneflow_api.BlobDesc

For example:

import cv2
import numpy as np
import oneflow as flow
import oneflow.typing as tp


def _of_image_normalize(images, image_shape, std, mean):
    func_config = flow.FunctionConfig()
    func_config.default_data_type(flow.float)
    func_config.default_logical_view(flow.scope.mirrored_view())

    @flow.global_function(function_config=func_config)
    def image_normalize_job(
        images_def: tp.ListListNumpy.Placeholder(shape=image_shape, dtype=flow.float)
    ) -> tp.ListListNumpy:
        # Convert to tensor buffer
        images_buffer = flow.tensor_list_to_tensor_buffer(images_def)
        # Normalize the imagess
        norm_images = flow.image_normalize(images_buffer, std, mean)
        # Convert back to tensor list
        return flow.tensor_buffer_to_tensor_list(
            norm_images, shape=image_shape[1:], dtype=flow.float
        )

    image_tensor = image_normalize_job([images])
    return image_tensor[0]


def _read_images_by_cv(image_files):
    images = [cv2.imread(image_file).astype(np.single) for image_file in image_files]
    return [np.expand_dims(image, axis=0) for image in images]


def _get_images_static_shape(images):
    image_shapes = [image.shape for image in images]
    image_static_shape = np.amax(image_shapes, axis=0)
    assert isinstance(
        image_static_shape, np.ndarray
    ), "image_shapes: {}, image_static_shape: {}".format(
        str(image_shapes), str(image_static_shape)
    )
    image_static_shape = image_static_shape.tolist()
    assert image_static_shape[0] == 1, str(image_static_shape)
    image_static_shape[0] = len(image_shapes)
    return image_static_shape

if __name__ == "__main__":
    img = _read_images_by_cv(['./img/1.jpg', './img/2.jpg', './img/3.jpg'])
    img_shape = _get_images_static_shape(img) # In example is [3, 349, 367, 3]
    image = _of_image_normalize(img,
                                tuple(img_shape),
                                std=(102.9801, 115.9465, 122.7717),
                                mean=(1.0, 1.0, 1.0))

oneflow.image.random_crop(input_blob: oneflow_api.BlobDesc, num_attempts: int = 10, seed: Optional[int] = None, random_area: Sequence[float] = None, random_aspect_ratio: Sequence[float] = None, name: str = 'ImageRandomCrop') → oneflow_api.BlobDesc

This operator crops the input image randomly.

Parameters

• input_blob (oneflow_api.BlobDesc) – The input Blob.

• num_attempts (int, optional) – The maximum number of random cropping attempts. Defaults to 10.

• seed (Optional[int], optional) – The random seed. Defaults to None.

• random_area (Sequence[float], optional) – The random cropping area. Defaults to None.

• random_aspect_ratio (Sequence[float], optional) – The random scaled ratio. Defaults to None.

• name (str, optional) – The name for the operation. Defaults to “ImageRandomCrop”.

Returns

The result Blob.

Return type

oneflow_api.BlobDesc

For example:

import oneflow as flow
import oneflow.typing as tp
import numpy as np
import cv2


def _read_images_by_cv(image_files):
    images = [cv2.imread(image_file).astype(np.single) for image_file in image_files]
    return [np.expand_dims(image, axis=0) for image in images]


def _get_images_static_shape(images):
    image_shapes = [image.shape for image in images]
    image_static_shape = np.amax(image_shapes, axis=0)
    assert isinstance(
        image_static_shape, np.ndarray
    ), "image_shapes: {}, image_static_shape: {}".format(
        str(image_shapes), str(image_static_shape)
    )
    image_static_shape = image_static_shape.tolist()
    assert image_static_shape[0] == 1, str(image_static_shape)
    image_static_shape[0] = len(image_shapes)
    return image_static_shape

def _of_image_random_crop(images, image_static_shape):
    func_config = flow.FunctionConfig()
    func_config.default_data_type(flow.float)
    func_config.default_logical_view(flow.scope.mirrored_view())

    @flow.global_function(function_config=func_config)
    def image_random_crop_job(images_def: tp.ListListNumpy.Placeholder(shape=image_static_shape, dtype=flow.float)
    ) -> tp.ListListNumpy:
        # The input Blob type should be "kTensorBuffer"
        # So we use oneflow.tensor_list_to_tensor_buffer to convert
        images_buffer = flow.tensor_list_to_tensor_buffer(images_def)
        # Do the random crop
        random_crop_buffer = flow.image.random_crop(
            images_buffer,
            random_area=[0.15, 0.80],
            random_aspect_ratio=[0.75, 1.55],
        )
        # We convert back to "tensorlist" type
        random_crop_images = flow.tensor_buffer_to_tensor_list(
            random_crop_buffer,
            shape=(image_static_shape[1], image_static_shape[2], image_static_shape[-1]),
            dtype=flow.float,
        )
        return random_crop_images

    random_crop_images = image_random_crop_job([images])

    return random_crop_images

if __name__ == "__main__":
    img = _read_images_by_cv(['./img/1.jpg'])
    img_shape = _get_images_static_shape(img) # In example is (1, 234, 346, 3)
    random_crop_images = _of_image_random_crop(img, tuple(img_shape))
    # random_crop_images.shape is (234, 346, 3)

oneflow.image.resize(image: oneflow_api.BlobDesc, target_size: Union[int, Sequence[int]] = None, min_size: Optional[int] = None, max_size: Optional[int] = None, keep_aspect_ratio: bool = False, resize_side: str = 'shorter', channels: int = 3, dtype: Optional[oneflow.python.framework.dtype.dtype] = None, interpolation_type: str = 'auto', name: Optional[str] = None, color_space: Optional[str] = None, interp_type: Optional[str] = None, resize_shorter: int = 0, resize_x: int = 0, resize_y: int = 0) → Union[oneflow_api.BlobDesc, Sequence[oneflow_api.BlobDesc]]

Resize images to target size.

Parameters

• image – A Tensor consists of images to be resized.

• target_size – A list or tuple when keep_aspect_ratio is false or an int when keep_aspect_ratio is true. When keep_aspect_ratio is false, target_size has a form of (target_width, target_height) that image will resize to. When keep_aspect_ratio is true, the longer side or shorter side of the image will be resized to target size.

• min_size – An int, optional. Only works when keep_aspect_ratio is true and resize_side is “longer”. If min_size is not None, the shorter side must be greater than or equal to min_size. Default is None.

• max_size – An int, optional. Only works when keep_aspect_ratio is true and resize_side is “shorter”. If max_size is not None, the longer side must be less than or equal to max_size. Default is None.

• keep_aspect_ratio – A bool. If is false, indicate that image will be resized to fixed width and height, otherwise image will be resized keeping aspect ratio.

• resize_side – A str of “longer” or “shorter”. Only works when keep_aspect_ratio is True. If resize_side is “longer”, the longer side of image will be resized to target_size. If resize_side is “shorter”, the shorter side of image will be resized to target_size.

• channels – An int. how many channels an image has

• dtype – oneflow.dtype. Indicate output resized image data type.

• interpolation_type – A str of “auto”, “bilinear”, “nearest_neighbor”, “bicubic” or “area”. Indicate interpolation method used to resize image.

• name – A str, optional. Name for the operation.

• color_space – Deprecated, a str of “RGB”, “BGR” or “GRAY”. Please use channels instead.

• interp_type – Deprecated, s str of “Linear”, “Cubic” or “NN”. Please use interpolation_type instead.

• resize_shorter – Deprecated, a int. Indicate target size that the shorter side of image will resize to. Please use target_size and resize_side instead.

• resize_x – Deprecated, a int. Indicate the target size that the width of image will resize to. Please use target_size instead.

• resize_y – Deprecated, a int. Indicate the target size that the height of image will resize to. Please use target_size instead.

Returns

Tuple of resized images Blob, width and height scales Blob and new width and height Blob (new width and height Blob will be None when keep_aspect_ratio is false). If deprecated params are used, a single resized images Blob will be returned.

For example:

import oneflow as flow
import oneflow.typing as tp
from typing import Tuple


@flow.global_function(type="predict")
def ofrecord_reader_job() -> Tuple[tp.Numpy, tp.Numpy]:
    batch_size = 16
    color_space = "RGB"
    # our ofrecord file path is "./dataset/part-0"
    ofrecord = flow.data.ofrecord_reader(
        "./imgdataset",
        batch_size=batch_size,
        data_part_num=1,
        part_name_suffix_length=-1,
        part_name_prefix='part-',
        random_shuffle=True,
        shuffle_after_epoch=True,
    )
    image = flow.data.OFRecordImageDecoderRandomCrop(
            ofrecord, "encoded", color_space=color_space
        )
    res_image, scale, new_size = flow.image.Resize(
            image, target_size=(224, 224)
        )
    label = flow.data.OFRecordRawDecoder(
        ofrecord, "class/label", shape=(1, ), dtype=flow.int32
    )

    return res_image, label

if __name__ == "__main__":
    images, labels = ofrecord_reader_job()
    # image.shape (16, 224, 224, 3)

oneflow.image.target_resize(images: oneflow_api.BlobDesc, target_size: int, min_size: Optional[int] = None, max_size: Optional[int] = None, resize_side: str = 'shorter', interpolation_type: str = 'auto', name: Optional[str] = None) → Sequence[oneflow_api.BlobDesc]

This operator resizes image to target size.

Parameters

• images (oneflow_api.BlobDesc) – The input Blob. Its type should be kTensorBuffer. More details please refer to the code example.

• target_size (int) – An int, the target size.

• min_size (Optional[int], optional) – If min_size is not None, the shorter side must be greater than or equal to min_size. Default is None. Defaults to None.

• max_size (Optional[int], optional) – If max_size is not None, the longer side must be less than or equal to max_size. Defaults to None.

• resize_side (str, optional) – A str of “longer” or “shorter”. Only works when keep_aspect_ratio is True. If resize_side is “longer”, the longer side of image will be resized to target_size. If resize_side is “shorter”, the shorter side of image will be resized to target_size. Defaults to “shorter”.

• interpolation_type (str, optional) – A str of “auto”, “bilinear”, “nearest_neighbor”, “bicubic” or “area”. Indicate interpolation method used to resize image. Defaults to “auto”.

• name (Optional[str], optional) – The name for the operation. Defaults to None.

Returns

A Sequence includes the result Blob.

Return type

Sequence[oneflow_api.BlobDesc]

For example:

import oneflow as flow
import oneflow.typing as tp
from typing import Tuple
import numpy as np
import cv2


def _read_images_by_cv(image_files):
    images = [cv2.imread(image_file).astype(np.single) for image_file in image_files]
    return [np.expand_dims(image, axis=0) for image in images]


def _get_images_static_shape(images):
    image_shapes = [image.shape for image in images]
    image_static_shape = np.amax(image_shapes, axis=0)
    assert isinstance(
        image_static_shape, np.ndarray
    ), "image_shapes: {}, image_static_shape: {}".format(
        str(image_shapes), str(image_static_shape)
    )
    image_static_shape = image_static_shape.tolist()
    assert image_static_shape[0] == 1, str(image_static_shape)
    image_static_shape[0] = len(image_shapes)
    return image_static_shape

def _of_image_target_resize(images, image_static_shape, target_size, max_size):
    func_config = flow.FunctionConfig()
    func_config.default_data_type(flow.float)
    func_config.default_logical_view(flow.scope.mirrored_view())

    @flow.global_function(function_config=func_config)
    def image_target_resize_job(images_def: tp.ListListNumpy.Placeholder(shape=image_static_shape, dtype=flow.float)
    ) -> Tuple[tp.ListListNumpy, tp.ListNumpy, tp.ListNumpy]:
        # The input Blob type should be "kTensorBuffer"
        # So we use oneflow.tensor_list_to_tensor_buffer to convert
        images_buffer = flow.tensor_list_to_tensor_buffer(images_def)

        resized_images_buffer, size, scale = flow.image_target_resize(
            images_buffer,
            target_size=target_size,
            max_size=max_size,
            resize_side="shorter",
        )
        # We convert back to "tensorlist" type
        resized_images = flow.tensor_buffer_to_tensor_list(
            resized_images_buffer,
            shape=(target_size, max_size, image_static_shape[-1]),
            dtype=flow.float,
        )
        return resized_images, size, scale

    resized_images, size, scale = image_target_resize_job([images])
    resized_image = resized_images[0]
    size = size[0]
    scale = scale[0]

    return resized_images, size, scale

if __name__ == "__main__":
    img = _read_images_by_cv(['./img/1.jpg'])
    img_shape = _get_images_static_shape(img) # In example is [1, 349, 367, 3]
    target_size = 256
    max_size = 512
    resized_images, size, scale = _of_image_target_resize(img, tuple(img_shape), target_size, max_size)
    # Here the shorter side is "349", we resize it to target_size(256)
    # The scale is 256 / 349 = 0.73
    # The longer side will be resized to 367 * scale = 269
    # get the first element from the resized_images (its type is `list.list`)
    print(resized_images[0][0].shape) # (1, 256, 269, 3)