File size: 5,182 Bytes
1803579
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
"""
Code adapted from SelfMask: https://github.com/NoelShin/selfmask
"""

from random import randint, random, uniform
from typing import Optional, Tuple, Union

import numpy as np
import torch
import torchvision.transforms.functional as TF
from PIL import Image
from torchvision.transforms.functional import InterpolationMode as IM


def random_crop(
    image: Union[Image.Image, np.ndarray, torch.Tensor],
    crop_size: Tuple[int, int],  # (h, w)
    fill: Union[int, Tuple[int, int, int]],  # an unsigned integer or RGB,
    offset: Optional[Tuple[int, int]] = None,  # (top, left) coordinate of a crop
):
    assert type(crop_size) in (tuple, list) and len(crop_size) == 2

    if isinstance(image, np.ndarray):
        image = torch.tensor(image)
        h, w = image.shape[-2:]
    elif isinstance(image, Image.Image):
        w, h = image.size
    elif isinstance(image, torch.Tensor):
        h, w = image.shape[-2:]
    else:
        raise TypeError(type(image))

    pad_h, pad_w = max(crop_size[0] - h, 0), max(crop_size[1] - w, 0)

    image = TF.pad(image, [0, 0, pad_w, pad_h], fill=fill, padding_mode="constant")

    if isinstance(image, Image.Image):
        w, h = image.size
    else:
        h, w = image.shape[-2:]

    if offset is None:
        offset = (randint(0, h - crop_size[0]), randint(0, w - crop_size[1]))

    image = TF.crop(
        image, top=offset[0], left=offset[1], height=crop_size[0], width=crop_size[1]
    )
    return image, offset


def compute_size(
    input_size: Tuple[int, int], output_size: int, edge: str  # h, w
) -> Tuple[int, int]:
    assert edge in ["shorter", "longer"]
    h, w = input_size

    if edge == "longer":
        if w > h:
            h = int(float(h) / w * output_size)
            w = output_size
        else:
            w = int(float(w) / h * output_size)
            h = output_size
        assert w <= output_size and h <= output_size

    else:
        if w > h:
            w = int(float(w) / h * output_size)
            h = output_size
        else:
            h = int(float(h) / w * output_size)
            w = output_size
        assert w >= output_size and h >= output_size
    return h, w


def resize(
    image: Union[Image.Image, np.ndarray, torch.Tensor],
    size: Union[int, Tuple[int, int]],
    interpolation: str,
    edge: str = "both",
) -> Union[Image.Image, torch.Tensor]:
    """
    :param image: an image to be resized
    :param size: a resulting image size
    :param interpolation: sampling mode. ["nearest", "bilinear", "bicubic"]
    :param edge: Default: "both"
    No-op if a size is given as a tuple (h, w).
    If set to "both", resize both height and width to the specified size.
    If set to "shorter", resize the shorter edge to the specified size keeping the aspect ratio.
    If set to "longer", resize the longer edge to the specified size keeping the aspect ratio.
    :return: a resized image
    """
    assert interpolation in ["nearest", "bilinear", "bicubic"], ValueError(
        interpolation
    )
    assert edge in ["both", "shorter", "longer"], ValueError(edge)
    interpolation = {
        "nearest": IM.NEAREST,
        "bilinear": IM.BILINEAR,
        "bicubic": IM.BICUBIC,
    }[interpolation]

    if type(image) == torch.Tensor:
        image = image.clone().detach()
    elif type(image) == np.ndarray:
        image = torch.from_numpy(image)

    if type(size) is tuple:
        if type(image) == torch.Tensor and len(image.shape) == 2:
            image = TF.resize(
                image.unsqueeze(dim=0), size=size, interpolation=interpolation
            ).squeeze(dim=0)
        else:
            image = TF.resize(image, size=size, interpolation=interpolation)

    else:
        if edge == "both":
            image = TF.resize(image, size=[size, size], interpolation=interpolation)

        else:
            if isinstance(image, Image.Image):
                w, h = image.size
            else:
                h, w = image.shape[-2:]
            rh, rw = compute_size(input_size=(h, w), output_size=size, edge=edge)
            image = TF.resize(image, size=[rh, rw], interpolation=interpolation)
    return image


def random_scale(
    image: Union[Image.Image, np.ndarray, torch.Tensor],
    random_scale_range: Tuple[float, float],
    mask: Optional[Union[Image.Image, np.ndarray, torch.Tensor]] = None,
):
    scale = uniform(*random_scale_range)
    if isinstance(image, Image.Image):
        w, h = image.size
    else:
        h, w = image.shape[-2:]
    w_rs, h_rs = int(w * scale), int(h * scale)
    image: Image.Image = resize(image, size=(h_rs, w_rs), interpolation="bilinear")
    if mask is not None:
        mask = resize(mask, size=(h_rs, w_rs), interpolation="nearest")
    return image, mask


def random_hflip(
    image: Union[Image.Image, np.ndarray, torch.Tensor],
    p: float,
    mask: Optional[Union[np.ndarray, torch.Tensor]] = None,
):
    assert 0.0 <= p <= 1.0, ValueError(random_hflip)

    # Return a random floating point number in the range [0.0, 1.0).
    if random() > p:
        image = TF.hflip(image)
        if mask is not None:
            mask = TF.hflip(mask)
    return image, mask