File size: 8,458 Bytes
4d0eb62
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
# Copyright (c) OpenMMLab. All rights reserved.
from typing import List, Optional

import torch
from mmengine.model import BaseModel
from torch import nn

from mmpretrain.registry import MODELS, TOKENIZER
from mmpretrain.structures import DataSample


@MODELS.register_module()
class Blip2Caption(BaseModel):
    """BLIP2 Caption.

    Module for BLIP2 Caption task.

    Args:
        vision_backbone (dict): The config dict for vision backbone.
        text_backbone (dict): The config dict for text backbone.
        multimodal_backbone (dict): The config dict for multimodal backbone.
        vision_neck (dict): The config dict for vision neck.
        tokenizer: (Optional[dict]): The config for tokenizer.
            Defaults to None.
        prompt (str): Prompt used for training and eval.
            Defaults to ''.
        max_txt_len (int): Max text length of input text.
        num_captions (int): Number of captions to be generated for each image.
        data_preprocessor (Optional[dict]): The config for preprocessing input
            data. If None or no specified type, it will use
            "MultiModalDataPreprocessor" as type.
            See :class:`MultiModalDataPreprocessor` for more details.
            Defaults to None.
        init_cfg (Optional[dict]): the config to control the initialization.
            Defaults to None.
    """
    _no_split_modules = ['BEiTViT', 'OPTDecoderLayer', 'BertLayer']

    def __init__(self,
                 vision_backbone: dict,
                 text_backbone: dict,
                 multimodal_backbone: dict,
                 vision_neck: dict,
                 tokenizer: Optional[dict] = None,
                 prompt: str = '',
                 max_txt_len: int = 20,
                 num_captions: int = 1,
                 data_preprocessor: Optional[dict] = None,
                 init_cfg: Optional[dict] = None) -> None:
        if data_preprocessor is None:
            data_preprocessor = {}
        if isinstance(data_preprocessor, dict):
            data_preprocessor.setdefault('type', 'MultiModalDataPreprocessor')
            data_preprocessor = MODELS.build(data_preprocessor)

        super().__init__(
            init_cfg=init_cfg, data_preprocessor=data_preprocessor)

        self.tokenizer = TOKENIZER.build(tokenizer)
        self.eos_token_id = self.tokenizer(
            '\n', add_special_tokens=False).input_ids[0]

        self.vision_backbone = MODELS.build(vision_backbone)
        self.ln_vision_backbone = nn.LayerNorm(self.vision_backbone.embed_dims)

        self.vision_neck = MODELS.build(vision_neck)

        self.text_backbone = MODELS.build(text_backbone)

        self.multimodal_backbone = MODELS.build(multimodal_backbone)
        self.multimodal_backbone.cls = None
        self.multimodal_backbone.bert.embeddings.word_embeddings = None
        self.multimodal_backbone.bert.embeddings.position_embeddings = None
        for layer in self.multimodal_backbone.bert.encoder.layer:
            layer.output = None
            layer.intermediate = None

        self.prompt = prompt
        self.max_txt_len = max_txt_len
        self.num_captions = num_captions
        prompt_tokens = self.tokenizer(prompt, return_tensors='pt')
        self.prompt_length = prompt_tokens.attention_mask.sum(1)

        self.query_tokens = nn.Parameter(
            torch.zeros(1, self.multimodal_backbone.bert.config.query_length,
                        self.multimodal_backbone.bert.config.hidden_size))
        self.query_tokens.data.normal_(
            mean=0.0,
            std=self.multimodal_backbone.bert.config.initializer_range)

        # freeze the text backbone
        for _, param in self.text_backbone.named_parameters():
            param.requires_grad = False

        if hasattr(self, 'register_load_state_dict_post_hook'):
            self.register_load_state_dict_post_hook(self._ignore_llm_keys_hook)

    def forward(
        self,
        images: torch.Tensor,
        data_samples: Optional[List] = None,
        mode: str = 'loss',
    ) -> List[DataSample]:
        """The unified entry for a forward process in both training and test.
        The method should accept two modes: "predict" and "loss":

        - "predict": Forward and return the predictions, which are fully
          processed to a list of :obj:`DataSample`.
        - "loss": Forward and return a dict of losses according to the given
          inputs and data samples.

        Note that this method doesn't handle neither back propagation nor
        optimizer updating, which are done in the :meth:`train_step`.

        Args:
            images (torch.Tensor): pre_processed img tensor  (N, C, ...).
            data_samples (List[DataSample], optional):
            mode (str): Return what kind of value. Defaults to 'loss'.

        Returns:
            The return type depends on ``mode``.
            - If ``mode="loss"``, return a dict of tensor.
        """
        if mode == 'loss':
            return self.loss(images, data_samples)
        elif mode == 'predict':
            return self.predict(images, data_samples)
        else:
            raise RuntimeError(f'Invalid mode "{mode}".')

    def predict(self,
                images: torch.Tensor,
                data_samples: Optional[list] = None,
                **kwargs) -> List[DataSample]:
        """Predict captions from a batch of inputs.

        Args:
            images (torch.Tensor): The input tensor with shape
                (N, C, ...) in general.
            data_samples (List[DataSample], optional): The annotation
                data of every samples. Defaults to None.
            **kwargs: Other keyword arguments accepted by the ``predict``
                method of :attr:`head`.

        Returns:
            List[DataSample]: Return list of data samples.
        """

        # extract image features from
        image_embeds = self.ln_vision_backbone(self.vision_backbone(images)[0])
        image_atts = torch.ones(
            image_embeds.size()[:-1],
            dtype=torch.long,
        ).to(images.device)

        # distill image features to query tokens
        query_tokens = self.query_tokens.expand(image_embeds.size(0), -1, -1)
        query_outputs = self.multimodal_backbone.bert(
            query_embeds=query_tokens,
            encoder_hidden_states=image_embeds,
            encoder_attention_mask=image_atts,
            return_dict=True,
        )
        inputs_opt = self.vision_neck([query_outputs.last_hidden_state])
        attns_opt = torch.ones(
            inputs_opt.size()[:-1], dtype=torch.long).to(images.device)

        prompt = [self.prompt] * image_embeds.size(0)

        opt_tokens = self.tokenizer(
            prompt, return_tensors='pt').to(images.device)
        input_ids = opt_tokens.input_ids
        attention_mask = torch.cat([attns_opt, opt_tokens.attention_mask],
                                   dim=1)

        query_embeds = inputs_opt

        outputs = self.text_backbone.generate(
            input_ids=input_ids,
            query_embeds=query_embeds,
            attention_mask=attention_mask,
            do_sample=False,
            top_p=0.9,
            temperature=1.,
            num_beams=5,
            max_new_tokens=self.max_txt_len,
            min_length=1,
            eos_token_id=self.eos_token_id,
            repetition_penalty=1.0,
            length_penalty=1.0,
            num_return_sequences=self.num_captions,
        )

        output_text = self.tokenizer.batch_decode(
            outputs[:, self.prompt_length:], skip_special_tokens=True)
        output_text = [text.strip() for text in output_text]

        out_data_samples = []
        if data_samples is None:
            data_samples = [None for _ in range(len(output_text))]

        for data_sample, decode_token in zip(data_samples, output_text):
            if data_sample is None:
                data_sample = DataSample()
            data_sample.pred_caption = decode_token
            out_data_samples.append(data_sample)

        return out_data_samples

    @staticmethod
    def _ignore_llm_keys_hook(module, incompatible_keys):
        """Avoid warning missing keys of the LLM model."""
        import re
        llm_pattern = '^text_backbone'
        for key in list(incompatible_keys.missing_keys):
            if re.match(llm_pattern, key):
                incompatible_keys.missing_keys.remove(key)