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| ''' | |
| * Copyright (c) 2022, salesforce.com, inc. | |
| * All rights reserved. | |
| * SPDX-License-Identifier: BSD-3-Clause | |
| * For full license text, see LICENSE.txt file in the repo root or https://opensource.org/licenses/BSD-3-Clause | |
| * By Junnan Li | |
| ''' | |
| import warnings | |
| warnings.filterwarnings("ignore") | |
| from models.vit import VisionTransformer, interpolate_pos_embed | |
| from models.med import BertConfig, BertModel, BertLMHeadModel | |
| from transformers import BertTokenizer | |
| import torch | |
| from torch import nn | |
| import torch.nn.functional as F | |
| import os | |
| from urllib.parse import urlparse | |
| from timm.models.hub import download_cached_file | |
| class BLIP_Base(nn.Module): | |
| def __init__(self, | |
| med_config = 'configs/med_config.json', | |
| image_size = 224, | |
| vit = 'base', | |
| vit_grad_ckpt = False, | |
| vit_ckpt_layer = 0, | |
| ): | |
| """ | |
| Args: | |
| med_config (str): path for the mixture of encoder-decoder model's configuration file | |
| image_size (int): input image size | |
| vit (str): model size of vision transformer | |
| """ | |
| super().__init__() | |
| self.visual_encoder, vision_width = create_vit(vit,image_size, vit_grad_ckpt, vit_ckpt_layer) | |
| self.tokenizer = init_tokenizer() | |
| med_config = BertConfig.from_json_file(med_config) | |
| med_config.encoder_width = vision_width | |
| self.text_encoder = BertModel(config=med_config, add_pooling_layer=False) | |
| def forward(self, image, caption, mode): | |
| assert mode in ['image', 'text', 'multimodal'], "mode parameter must be image, text, or multimodal" | |
| text = self.tokenizer(caption, return_tensors="pt").to(image.device) | |
| if mode=='image': | |
| # return image features | |
| image_embeds = self.visual_encoder(image) | |
| return image_embeds | |
| elif mode=='text': | |
| # return text features | |
| text_output = self.text_encoder(text.input_ids, attention_mask = text.attention_mask, | |
| return_dict = True, mode = 'text') | |
| return text_output.last_hidden_state | |
| elif mode=='multimodal': | |
| # return multimodel features | |
| image_embeds = self.visual_encoder(image) | |
| image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device) | |
| text.input_ids[:,0] = self.tokenizer.enc_token_id | |
| output = self.text_encoder(text.input_ids, | |
| attention_mask = text.attention_mask, | |
| encoder_hidden_states = image_embeds, | |
| encoder_attention_mask = image_atts, | |
| return_dict = True, | |
| ) | |
| return output.last_hidden_state | |
| class BLIP_Decoder(nn.Module): | |
| def __init__(self, | |
| med_config = 'configs/med_config.json', | |
| image_size = 384, | |
| vit = 'base', | |
| vit_grad_ckpt = False, | |
| vit_ckpt_layer = 0, | |
| prompt = 'a picture of ', | |
| ): | |
| """ | |
| Args: | |
| med_config (str): path for the mixture of encoder-decoder model's configuration file | |
| image_size (int): input image size | |
| vit (str): model size of vision transformer | |
| """ | |
| super().__init__() | |
| self.visual_encoder, vision_width = create_vit(vit,image_size, vit_grad_ckpt, vit_ckpt_layer) | |
| self.tokenizer = init_tokenizer() | |
| med_config = BertConfig.from_json_file(med_config) | |
| med_config.encoder_width = vision_width | |
| self.text_decoder = BertLMHeadModel(config=med_config) | |
| self.prompt = prompt | |
| self.prompt_length = len(self.tokenizer(self.prompt).input_ids)-1 | |
| def forward(self, image, caption): | |
| image_embeds = self.visual_encoder(image) | |
| image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device) | |
| text = self.tokenizer(caption, padding='longest', truncation=True, max_length=40, return_tensors="pt").to(image.device) | |
| text.input_ids[:,0] = self.tokenizer.bos_token_id | |
| decoder_targets = text.input_ids.masked_fill(text.input_ids == self.tokenizer.pad_token_id, -100) | |
| decoder_targets[:,:self.prompt_length] = -100 | |
| decoder_output = self.text_decoder(text.input_ids, | |
| attention_mask = text.attention_mask, | |
| encoder_hidden_states = image_embeds, | |
| encoder_attention_mask = image_atts, | |
| labels = decoder_targets, | |
| return_dict = True, | |
| ) | |
| loss_lm = decoder_output.loss | |
| return loss_lm | |
| def generate(self, image, sample=False, num_beams=3, max_length=30, min_length=10, top_p=0.9, repetition_penalty=1.0): | |
| image_embeds = self.visual_encoder(image) | |
| if not sample: | |
| image_embeds = image_embeds.repeat_interleave(num_beams,dim=0) | |
| image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device) | |
| model_kwargs = {"encoder_hidden_states": image_embeds, "encoder_attention_mask":image_atts} | |
| prompt = [self.prompt] * image.size(0) | |
| input_ids = self.tokenizer(prompt, return_tensors="pt").input_ids.to(image.device) | |
| input_ids[:,0] = self.tokenizer.bos_token_id | |
| input_ids = input_ids[:, :-1] | |
| if sample: | |
| #nucleus sampling | |
| outputs = self.text_decoder.generate(input_ids=input_ids, | |
| max_length=max_length, | |
| min_length=min_length, | |
| do_sample=True, | |
| top_p=top_p, | |
| num_return_sequences=1, | |
| eos_token_id=self.tokenizer.sep_token_id, | |
| pad_token_id=self.tokenizer.pad_token_id, | |
| repetition_penalty=1.1, | |
| **model_kwargs) | |
| else: | |
| #beam search | |
| outputs = self.text_decoder.generate(input_ids=input_ids, | |
| max_length=max_length, | |
| min_length=min_length, | |
| num_beams=num_beams, | |
| eos_token_id=self.tokenizer.sep_token_id, | |
| pad_token_id=self.tokenizer.pad_token_id, | |
| repetition_penalty=repetition_penalty, | |
| **model_kwargs) | |
| captions = [] | |
| for output in outputs: | |
| caption = self.tokenizer.decode(output, skip_special_tokens=True) | |
| captions.append(caption[len(self.prompt):]) | |
| return captions | |
| def blip_decoder(pretrained='',**kwargs): | |
| model = BLIP_Decoder(**kwargs) | |
| if pretrained: | |
| model,msg = load_checkpoint(model,pretrained) | |
| assert(len(msg.missing_keys)==0) | |
| return model | |
| def blip_feature_extractor(pretrained='',**kwargs): | |
| model = BLIP_Base(**kwargs) | |
| if pretrained: | |
| model,msg = load_checkpoint(model,pretrained) | |
| assert(len(msg.missing_keys)==0) | |
| return model | |
| def init_tokenizer(): | |
| tokenizer = BertTokenizer.from_pretrained('bert-base-uncased') | |
| tokenizer.add_special_tokens({'bos_token':'[DEC]'}) | |
| tokenizer.add_special_tokens({'additional_special_tokens':['[ENC]']}) | |
| tokenizer.enc_token_id = tokenizer.additional_special_tokens_ids[0] | |
| return tokenizer | |
| def create_vit(vit, image_size, use_grad_checkpointing=False, ckpt_layer=0, drop_path_rate=0): | |
| assert vit in ['base', 'large'], "vit parameter must be base or large" | |
| if vit=='base': | |
| vision_width = 768 | |
| visual_encoder = VisionTransformer(img_size=image_size, patch_size=16, embed_dim=vision_width, depth=12, | |
| num_heads=12, use_grad_checkpointing=use_grad_checkpointing, ckpt_layer=ckpt_layer, | |
| drop_path_rate=0 or drop_path_rate | |
| ) | |
| elif vit=='large': | |
| vision_width = 1024 | |
| visual_encoder = VisionTransformer(img_size=image_size, patch_size=16, embed_dim=vision_width, depth=24, | |
| num_heads=16, use_grad_checkpointing=use_grad_checkpointing, ckpt_layer=ckpt_layer, | |
| drop_path_rate=0.1 or drop_path_rate | |
| ) | |
| return visual_encoder, vision_width | |
| def is_url(url_or_filename): | |
| parsed = urlparse(url_or_filename) | |
| return parsed.scheme in ("http", "https") | |
| def load_checkpoint(model,url_or_filename): | |
| if is_url(url_or_filename): | |
| cached_file = download_cached_file(url_or_filename, check_hash=False, progress=True) | |
| checkpoint = torch.load(cached_file, map_location='cpu') | |
| elif os.path.isfile(url_or_filename): | |
| checkpoint = torch.load(url_or_filename, map_location='cpu') | |
| else: | |
| raise RuntimeError('checkpoint url or path is invalid') | |
| state_dict = checkpoint['model'] | |
| state_dict['visual_encoder.pos_embed'] = interpolate_pos_embed(state_dict['visual_encoder.pos_embed'],model.visual_encoder) | |
| if 'visual_encoder_m.pos_embed' in model.state_dict().keys(): | |
| state_dict['visual_encoder_m.pos_embed'] = interpolate_pos_embed(state_dict['visual_encoder_m.pos_embed'], | |
| model.visual_encoder_m) | |
| for key in model.state_dict().keys(): | |
| if key in state_dict.keys(): | |
| if state_dict[key].shape!=model.state_dict()[key].shape: | |
| del state_dict[key] | |
| msg = model.load_state_dict(state_dict,strict=False) | |
| print('load checkpoint from %s'%url_or_filename) | |
| return model,msg | |