File size: 6,338 Bytes
17cfe57
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
f8588ad
 
17cfe57
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
163ed4a
 
17cfe57
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
from PIL import Image, ImageChops
import numpy as np
import cv2 as cv
import math
import torch
from torch.nn import functional as F

"""
Borrowed and adapted from https://github.com/xinntao/Real-ESRGAN/blob/master/realesrgan/utils.py
Thank you xinntao! 
"""
class ESRGANer():
    """A helper class for upsampling images with ESRGAN.

    Args:
        scale (int): Upsampling scale factor used in the networks. It is usually 2 or 4.
        model (nn.Module): The defined network. Default: None.
        tile (int): As too large images result in the out of GPU memory issue, so this tile option will first crop
            input images into tiles, and then process each of them. Finally, they will be merged into one image.
            0 denotes for do not use tile. Default: 500.
        tile_pad (int): The pad size for each tile, to remove border artifacts. Default: 10.
        pre_pad (int): Pad the input images to avoid border artifacts. Default: 10.
    """

    def __init__(self,
                 scale=4,
                 model=None,
                 tile=300,
                 tile_pad=10,
                 pre_pad=10
        ):
        self.scale = scale
        self.tile_size = tile
        self.tile_pad = tile_pad
        self.pre_pad = pre_pad
        self.mod_scale = None

        self.model = model

    def pre_process(self, img):
        """Pre-process, such as pre-pad and mod pad, so that the images can be divisible
        """
        self.img = img

        # pre_pad
        if self.pre_pad != 0:
            self.img = F.pad(self.img, (0, self.pre_pad, 0, self.pre_pad), 'reflect')
        # mod pad for divisible borders
        if self.scale == 2:
            self.mod_scale = 2
        elif self.scale == 1:
            self.mod_scale = 4
        if self.mod_scale is not None:
            self.mod_pad_h, self.mod_pad_w = 0, 0
            _, _, h, w = self.img.size()
            if (h % self.mod_scale != 0):
                self.mod_pad_h = (self.mod_scale - h % self.mod_scale)
            if (w % self.mod_scale != 0):
                self.mod_pad_w = (self.mod_scale - w % self.mod_scale)
            self.img = F.pad(self.img, (0, self.mod_pad_w, 0, self.mod_pad_h), 'reflect')

    def process(self):
        # model inference
        self.output = self.model(self.img)

    def tile_process(self):
        """It will first crop input images to tiles, and then process each tile.
        Finally, all the processed tiles are merged into one images.

        Modified from: https://github.com/ata4/esrgan-launcher
        """
        batch, channel, height, width = self.img.shape
        output_height = height * self.scale
        output_width = width * self.scale
        output_shape = (batch, channel, output_height, output_width)

        # start with black image
        self.output = self.img.new_zeros(output_shape)
        tiles_x = math.ceil(width / self.tile_size)
        tiles_y = math.ceil(height / self.tile_size)

        print("Image processing started...")

        # loop over all tiles
        for y in range(tiles_y):
            for x in range(tiles_x):
                # extract tile from input image
                ofs_x = x * self.tile_size
                ofs_y = y * self.tile_size
                # input tile area on total image
                input_start_x = ofs_x
                input_end_x = min(ofs_x + self.tile_size, width)
                input_start_y = ofs_y
                input_end_y = min(ofs_y + self.tile_size, height)

                # input tile area on total image with padding
                input_start_x_pad = max(input_start_x - self.tile_pad, 0)
                input_end_x_pad = min(input_end_x + self.tile_pad, width)
                input_start_y_pad = max(input_start_y - self.tile_pad, 0)
                input_end_y_pad = min(input_end_y + self.tile_pad, height)

                # input tile dimensions
                input_tile_width = input_end_x - input_start_x
                input_tile_height = input_end_y - input_start_y
                tile_idx = y * tiles_x + x + 1
                input_tile = self.img[:, :, input_start_y_pad:input_end_y_pad, input_start_x_pad:input_end_x_pad]

                # upscale tile
                try:
                    with torch.no_grad():
                        output_tile = self.model(input_tile)
                except RuntimeError as error:
                    print('Error', error)
                print(f'Processing tile {tile_idx}/{tiles_x * tiles_y}')

                # output tile area on total image
                output_start_x = input_start_x * self.scale
                output_end_x = input_end_x * self.scale
                output_start_y = input_start_y * self.scale
                output_end_y = input_end_y * self.scale

                # output tile area without padding
                output_start_x_tile = (input_start_x - input_start_x_pad) * self.scale
                output_end_x_tile = output_start_x_tile + input_tile_width * self.scale
                output_start_y_tile = (input_start_y - input_start_y_pad) * self.scale
                output_end_y_tile = output_start_y_tile + input_tile_height * self.scale

                # put tile into output image
                self.output[:, :, output_start_y:output_end_y,
                            output_start_x:output_end_x] = output_tile[:, :, output_start_y_tile:output_end_y_tile,
                                                                       output_start_x_tile:output_end_x_tile]

        print('All tiles processed, saving output image!')

    def post_process(self):
        # remove extra pad
        if self.mod_scale is not None:
            _, _, h, w = self.output.size()
            self.output = self.output[:, :, 0:h - self.mod_pad_h * self.scale, 0:w - self.mod_pad_w * self.scale]
        # remove prepad
        if self.pre_pad != 0:
            _, _, h, w = self.output.size()
            self.output = self.output[:, :, 0:h - self.pre_pad * self.scale, 0:w - self.pre_pad * self.scale]
        return self.output
    
    @torch.no_grad()
    def enhance(self, img):
        self.pre_process(img)

        if self.tile_size > 0:
            self.tile_process()
        else:
            self.process()
        output_img = self.post_process()

        return output_img