Transformers documentation
VisionTextDualEncoder
This model was released on 2021-11-15 and added to Hugging Face Transformers on 2021-11-30.
VisionTextDualEncoder
Overview
The VisionTextDualEncoderModel can be used to initialize a vision-text dual encoder model with any pretrained vision autoencoding model as the vision encoder (e.g. ViT, BEiT, DeiT) and any pretrained text autoencoding model as the text encoder (e.g. RoBERTa, BERT). Two projection layers are added on top of both the vision and text encoder to project the output embeddings to a shared latent space. The projection layers are randomly initialized so the model should be fine-tuned on a downstream task. This model can be used to align the vision-text embeddings using CLIP like contrastive image-text training and then can be used for zero-shot vision tasks such image-classification or retrieval.
In LiT: Zero-Shot Transfer with Locked-image Text Tuning it is shown how leveraging pre-trained (locked/frozen) image and text model for contrastive learning yields significant improvement on new zero-shot vision tasks such as image classification or retrieval.
VisionTextDualEncoderConfig
class transformers.VisionTextDualEncoderConfig
< source >( projection_dim = 512 logit_scale_init_value = 2.6592 **kwargs )
Parameters
- projection_dim (
int
, optional, defaults to 512) — Dimensionality of text and vision projection layers. - logit_scale_init_value (
float
, optional, defaults to 2.6592) — The initial value of the logit_scale parameter. Default is used as per the original CLIP implementation. - kwargs (optional) — Dictionary of keyword arguments.
VisionTextDualEncoderConfig is the configuration class to store the configuration of a VisionTextDualEncoderModel. It is used to instantiate VisionTextDualEncoderModel model according to the specified arguments, defining the text model and vision model configs.
Configuration objects inherit from PretrainedConfig and can be used to control the model outputs. Read the documentation from PretrainedConfig for more information.
Examples:
>>> from transformers import ViTConfig, BertConfig, VisionTextDualEncoderConfig, VisionTextDualEncoderModel
>>> # Initializing a BERT and ViT configuration
>>> config_vision = ViTConfig()
>>> config_text = BertConfig()
>>> config = VisionTextDualEncoderConfig.from_vision_text_configs(config_vision, config_text, projection_dim=512)
>>> # Initializing a BERT and ViT model (with random weights)
>>> model = VisionTextDualEncoderModel(config=config)
>>> # Accessing the model configuration
>>> config_vision = model.config.vision_config
>>> config_text = model.config.text_config
>>> # Saving the model, including its configuration
>>> model.save_pretrained("vit-bert")
>>> # loading model and config from pretrained folder
>>> vision_text_config = VisionTextDualEncoderConfig.from_pretrained("vit-bert")
>>> model = VisionTextDualEncoderModel.from_pretrained("vit-bert", config=vision_text_config)
from_vision_text_configs
< source >( vision_config: PretrainedConfig text_config: PretrainedConfig **kwargs ) → VisionTextDualEncoderConfig
Instantiate a VisionTextDualEncoderConfig (or a derived class) from text model configuration and vision model configuration.
VisionTextDualEncoderProcessor
class transformers.VisionTextDualEncoderProcessor
< source >( image_processor = None tokenizer = None **kwargs )
Parameters
- image_processor (AutoImageProcessor, optional) — The image processor is a required input.
- tokenizer (PreTrainedTokenizer, optional) — The tokenizer is a required input.
Constructs a VisionTextDualEncoder processor which wraps an image processor and a tokenizer into a single processor.
VisionTextDualEncoderProcessor offers all the functionalities of AutoImageProcessor and AutoTokenizer.
See the __call__()
and decode() for more
information.
VisionTextDualEncoderModel
class transformers.VisionTextDualEncoderModel
< source >( config: typing.Optional[transformers.models.vision_text_dual_encoder.configuration_vision_text_dual_encoder.VisionTextDualEncoderConfig] = None vision_model: typing.Optional[transformers.modeling_utils.PreTrainedModel] = None text_model: typing.Optional[transformers.modeling_utils.PreTrainedModel] = None )
Parameters
- config (VisionTextDualEncoderConfig, optional) — Model configuration class with all the parameters of the model. Initializing with a config file does not load the weights associated with the model, only the configuration. Check out the from_pretrained() method to load the model weights.
- vision_model (
~modeling_utils.PreTrainedModel
, optional) — The vision model to use. - text_model (
~modeling_utils.PreTrainedModel
, optional) — The text model to use.
The bare Vision Text Dual Encoder Model outputting raw hidden-states without any specific head on top.
This model inherits from PreTrainedModel. Check the superclass documentation for the generic methods the library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads etc.)
This model is also a PyTorch torch.nn.Module subclass. Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and behavior.
forward
< source >( input_ids: typing.Optional[torch.LongTensor] = None pixel_values: typing.Optional[torch.FloatTensor] = None attention_mask: typing.Optional[torch.Tensor] = None position_ids: typing.Optional[torch.LongTensor] = None return_loss: typing.Optional[bool] = None token_type_ids: typing.Optional[torch.LongTensor] = None output_attentions: typing.Optional[bool] = None output_hidden_states: typing.Optional[bool] = None return_dict: typing.Optional[bool] = None ) → transformers.models.clip.modeling_clip.CLIPOutput
or tuple(torch.FloatTensor)
Parameters
- input_ids (
torch.LongTensor
of shape(batch_size, sequence_length)
, optional) — Indices of input sequence tokens in the vocabulary. Padding will be ignored by default.Indices can be obtained using AutoTokenizer. See PreTrainedTokenizer.encode() and PreTrainedTokenizer.call() for details.
- pixel_values (
torch.FloatTensor
of shape(batch_size, num_channels, image_size, image_size)
, optional) — The tensors corresponding to the input images. Pixel values can be obtained usingimage_processor_class
. Seeimage_processor_class.__call__
for details (VisionTextDualEncoderProcessor usesimage_processor_class
for processing images). - attention_mask (
torch.Tensor
of shape(batch_size, sequence_length)
, optional) — Mask to avoid performing attention on padding token indices. Mask values selected in[0, 1]
:- 1 for tokens that are not masked,
- 0 for tokens that are masked.
- position_ids (
torch.LongTensor
of shape(batch_size, sequence_length)
, optional) — Indices of positions of each input sequence tokens in the position embeddings. Selected in the range[0, config.n_positions - 1]
. - return_loss (
bool
, optional) — Whether or not to return the contrastive loss. - token_type_ids (
torch.LongTensor
of shape(batch_size, sequence_length)
, optional) — Segment token indices to indicate first and second portions of the inputs. Indices are selected in[0, 1]
:- 0 corresponds to a sentence A token,
- 1 corresponds to a sentence B token.
- output_attentions (
bool
, optional) — Whether or not to return the attentions tensors of all attention layers. Seeattentions
under returned tensors for more detail. - output_hidden_states (
bool
, optional) — Whether or not to return the hidden states of all layers. Seehidden_states
under returned tensors for more detail. - return_dict (
bool
, optional) — Whether or not to return a ModelOutput instead of a plain tuple.
Returns
transformers.models.clip.modeling_clip.CLIPOutput
or tuple(torch.FloatTensor)
A transformers.models.clip.modeling_clip.CLIPOutput
or a tuple of
torch.FloatTensor
(if return_dict=False
is passed or when config.return_dict=False
) comprising various
elements depending on the configuration (VisionTextDualEncoderConfig) and inputs.
- loss (
torch.FloatTensor
of shape(1,)
, optional, returned whenreturn_loss
isTrue
) — Contrastive loss for image-text similarity. - logits_per_image (
torch.FloatTensor
of shape(image_batch_size, text_batch_size)
) — The scaled dot product scores betweenimage_embeds
andtext_embeds
. This represents the image-text similarity scores. - logits_per_text (
torch.FloatTensor
of shape(text_batch_size, image_batch_size)
) — The scaled dot product scores betweentext_embeds
andimage_embeds
. This represents the text-image similarity scores. - text_embeds (
torch.FloatTensor
of shape(batch_size, output_dim
) — The text embeddings obtained by applying the projection layer to the pooled output of CLIPTextModel. - image_embeds (
torch.FloatTensor
of shape(batch_size, output_dim
) — The image embeddings obtained by applying the projection layer to the pooled output of CLIPVisionModel. - text_model_output (
<class '~modeling_outputs.BaseModelOutputWithPooling'>.text_model_output
, defaults toNone
) — The output of the CLIPTextModel. - vision_model_output (
<class '~modeling_outputs.BaseModelOutputWithPooling'>.vision_model_output
, defaults toNone
) — The output of the CLIPVisionModel.
The VisionTextDualEncoderModel forward method, overrides the __call__
special method.
Although the recipe for forward pass needs to be defined within this function, one should call the Module
instance afterwards instead of this since the former takes care of running the pre and post processing steps while
the latter silently ignores them.
Examples:
>>> from PIL import Image
>>> import requests
>>> from transformers import (
... VisionTextDualEncoderModel,
... VisionTextDualEncoderProcessor,
... AutoImageProcessor,
... AutoTokenizer,
... )
>>> tokenizer = AutoTokenizer.from_pretrained("google-bert/bert-base-uncased")
>>> image_processor = AutoImageProcessor.from_pretrained("google/vit-base-patch16-224")
>>> processor = VisionTextDualEncoderProcessor(image_processor, tokenizer)
>>> model = VisionTextDualEncoderModel.from_vision_text_pretrained(
... "google/vit-base-patch16-224", "google-bert/bert-base-uncased"
... )
>>> # contrastive training
>>> urls = [
... "http://images.cocodataset.org/val2017/000000039769.jpg",
... "https://farm3.staticflickr.com/2674/5850229113_4fe05d5265_z.jpg",
... ]
>>> images = [Image.open(requests.get(url, stream=True).raw) for url in urls]
>>> inputs = processor(
... text=["a photo of a cat", "a photo of a dog"], images=images, return_tensors="pt", padding=True
... )
>>> outputs = model(
... input_ids=inputs.input_ids,
... attention_mask=inputs.attention_mask,
... pixel_values=inputs.pixel_values,
... return_loss=True,
... )
>>> loss, logits_per_image = outputs.loss, outputs.logits_per_image # this is the image-text similarity score
>>> # save and load from pretrained
>>> model.save_pretrained("vit-bert")
>>> model = VisionTextDualEncoderModel.from_pretrained("vit-bert")
>>> # inference
>>> outputs = model(**inputs)
>>> logits_per_image = outputs.logits_per_image # this is the image-text similarity score
>>> probs = logits_per_image.softmax(dim=1) # we can take the softmax to get the label probabilities