File size: 7,682 Bytes
3b96cb1
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
# Copyright (c) OpenMMLab. All rights reserved.
from typing import Sequence

from torch.utils.data import BatchSampler, Sampler

from mmdet.datasets.samplers.track_img_sampler import TrackImgSampler
from mmdet.registry import DATA_SAMPLERS


# TODO: maybe replace with a data_loader wrapper
@DATA_SAMPLERS.register_module()
class AspectRatioBatchSampler(BatchSampler):
    """A sampler wrapper for grouping images with similar aspect ratio (< 1 or.

    >= 1) into a same batch.

    Args:
        sampler (Sampler): Base sampler.
        batch_size (int): Size of mini-batch.
        drop_last (bool): If ``True``, the sampler will drop the last batch if
            its size would be less than ``batch_size``.
    """

    def __init__(self,
                 sampler: Sampler,
                 batch_size: int,
                 drop_last: bool = False) -> None:
        if not isinstance(sampler, Sampler):
            raise TypeError('sampler should be an instance of ``Sampler``, '
                            f'but got {sampler}')
        if not isinstance(batch_size, int) or batch_size <= 0:
            raise ValueError('batch_size should be a positive integer value, '
                             f'but got batch_size={batch_size}')
        self.sampler = sampler
        self.batch_size = batch_size
        self.drop_last = drop_last
        # two groups for w < h and w >= h
        self._aspect_ratio_buckets = [[] for _ in range(2)]

    def __iter__(self) -> Sequence[int]:
        for idx in self.sampler:
            data_info = self.sampler.dataset.get_data_info(idx)
            width, height = data_info['width'], data_info['height']
            bucket_id = 0 if width < height else 1
            bucket = self._aspect_ratio_buckets[bucket_id]
            bucket.append(idx)
            # yield a batch of indices in the same aspect ratio group
            if len(bucket) == self.batch_size:
                yield bucket[:]
                del bucket[:]

        # yield the rest data and reset the bucket
        left_data = self._aspect_ratio_buckets[0] + self._aspect_ratio_buckets[
            1]
        self._aspect_ratio_buckets = [[] for _ in range(2)]
        while len(left_data) > 0:
            if len(left_data) <= self.batch_size:
                if not self.drop_last:
                    yield left_data[:]
                left_data = []
            else:
                yield left_data[:self.batch_size]
                left_data = left_data[self.batch_size:]

    def __len__(self) -> int:
        if self.drop_last:
            return len(self.sampler) // self.batch_size
        else:
            return (len(self.sampler) + self.batch_size - 1) // self.batch_size


@DATA_SAMPLERS.register_module()
class TrackAspectRatioBatchSampler(AspectRatioBatchSampler):
    """A sampler wrapper for grouping images with similar aspect ratio (< 1 or.

    >= 1) into a same batch.

    Args:
        sampler (Sampler): Base sampler.
        batch_size (int): Size of mini-batch.
        drop_last (bool): If ``True``, the sampler will drop the last batch if
            its size would be less than ``batch_size``.
    """

    def __iter__(self) -> Sequence[int]:
        for idx in self.sampler:
            # hard code to solve TrackImgSampler
            if isinstance(self.sampler, TrackImgSampler):
                video_idx, _ = idx
            else:
                video_idx = idx
            # video_idx
            data_info = self.sampler.dataset.get_data_info(video_idx)
            # data_info {video_id, images, video_length}
            img_data_info = data_info['images'][0]
            width, height = img_data_info['width'], img_data_info['height']
            bucket_id = 0 if width < height else 1
            bucket = self._aspect_ratio_buckets[bucket_id]
            bucket.append(idx)
            # yield a batch of indices in the same aspect ratio group
            if len(bucket) == self.batch_size:
                yield bucket[:]
                del bucket[:]

        # yield the rest data and reset the bucket
        left_data = self._aspect_ratio_buckets[0] + self._aspect_ratio_buckets[
            1]
        self._aspect_ratio_buckets = [[] for _ in range(2)]
        while len(left_data) > 0:
            if len(left_data) <= self.batch_size:
                if not self.drop_last:
                    yield left_data[:]
                left_data = []
            else:
                yield left_data[:self.batch_size]
                left_data = left_data[self.batch_size:]


@DATA_SAMPLERS.register_module()
class MultiDataAspectRatioBatchSampler(BatchSampler):
    """A sampler wrapper for grouping images with similar aspect ratio (< 1 or.

    >= 1) into a same batch for multi-source datasets.

    Args:
        sampler (Sampler): Base sampler.
        batch_size (Sequence(int)): Size of mini-batch for multi-source
        datasets.
        num_datasets(int): Number of multi-source datasets.
        drop_last (bool): If ``True``, the sampler will drop the last batch if
        its size would be less than ``batch_size``.
    """

    def __init__(self,
                 sampler: Sampler,
                 batch_size: Sequence[int],
                 num_datasets: int,
                 drop_last: bool = True) -> None:
        if not isinstance(sampler, Sampler):
            raise TypeError('sampler should be an instance of ``Sampler``, '
                            f'but got {sampler}')
        self.sampler = sampler
        self.batch_size = batch_size
        self.num_datasets = num_datasets
        self.drop_last = drop_last
        # two groups for w < h and w >= h for each dataset --> 2 * num_datasets
        self._buckets = [[] for _ in range(2 * self.num_datasets)]

    def __iter__(self) -> Sequence[int]:
        for idx in self.sampler:
            data_info = self.sampler.dataset.get_data_info(idx)
            width, height = data_info['width'], data_info['height']
            dataset_source_idx = self.sampler.dataset.get_dataset_source(idx)
            aspect_ratio_bucket_id = 0 if width < height else 1
            bucket_id = dataset_source_idx * 2 + aspect_ratio_bucket_id
            bucket = self._buckets[bucket_id]
            bucket.append(idx)
            # yield a batch of indices in the same aspect ratio group
            if len(bucket) == self.batch_size[dataset_source_idx]:
                yield bucket[:]
                del bucket[:]

        # yield the rest data and reset the bucket
        for i in range(self.num_datasets):
            left_data = self._buckets[i * 2 + 0] + self._buckets[i * 2 + 1]
            while len(left_data) > 0:
                if len(left_data) <= self.batch_size[i]:
                    if not self.drop_last:
                        yield left_data[:]
                    left_data = []
                else:
                    yield left_data[:self.batch_size[i]]
                    left_data = left_data[self.batch_size[i]:]

        self._buckets = [[] for _ in range(2 * self.num_datasets)]

    def __len__(self) -> int:
        sizes = [0 for _ in range(self.num_datasets)]
        for idx in self.sampler:
            dataset_source_idx = self.sampler.dataset.get_dataset_source(idx)
            sizes[dataset_source_idx] += 1

        if self.drop_last:
            lens = 0
            for i in range(self.num_datasets):
                lens += sizes[i] // self.batch_size[i]
            return lens
        else:
            lens = 0
            for i in range(self.num_datasets):
                lens += (sizes[i] + self.batch_size[i] -
                         1) // self.batch_size[i]
            return lens