# coding=utf-8 # Copyright 2022 School of EIC, Huazhong University of Science & Technology and The HuggingFace Inc. team. All rights reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """ PyTorch YOLOS model.""" import collections.abc import math from dataclasses import dataclass from typing import Dict, List, Optional, Set, Tuple, Union import torch import torch.utils.checkpoint from torch import Tensor, nn from ...activations import ACT2FN from ...modeling_outputs import BaseModelOutput, BaseModelOutputWithPooling from ...modeling_utils import PreTrainedModel from ...pytorch_utils import find_pruneable_heads_and_indices, prune_linear_layer from ...utils import ( ModelOutput, add_code_sample_docstrings, add_start_docstrings, add_start_docstrings_to_model_forward, is_scipy_available, is_vision_available, logging, replace_return_docstrings, requires_backends, ) from .configuration_yolos import YolosConfig if is_scipy_available(): from scipy.optimize import linear_sum_assignment if is_vision_available(): from transformers.image_transforms import center_to_corners_format logger = logging.get_logger(__name__) # General docstring _CONFIG_FOR_DOC = "YolosConfig" # Base docstring _CHECKPOINT_FOR_DOC = "hustvl/yolos-small" _EXPECTED_OUTPUT_SHAPE = [1, 3401, 384] YOLOS_PRETRAINED_MODEL_ARCHIVE_LIST = [ "hustvl/yolos-small", # See all YOLOS models at https://huggingface.co/models?filter=yolos ] @dataclass class YolosObjectDetectionOutput(ModelOutput): """ Output type of [`YolosForObjectDetection`]. Args: loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` are provided)): Total loss as a linear combination of a negative log-likehood (cross-entropy) for class prediction and a bounding box loss. The latter is defined as a linear combination of the L1 loss and the generalized scale-invariant IoU loss. loss_dict (`Dict`, *optional*): A dictionary containing the individual losses. Useful for logging. logits (`torch.FloatTensor` of shape `(batch_size, num_queries, num_classes + 1)`): Classification logits (including no-object) for all queries. pred_boxes (`torch.FloatTensor` of shape `(batch_size, num_queries, 4)`): Normalized boxes coordinates for all queries, represented as (center_x, center_y, width, height). These values are normalized in [0, 1], relative to the size of each individual image in the batch (disregarding possible padding). You can use [`~YolosImageProcessor.post_process`] to retrieve the unnormalized bounding boxes. auxiliary_outputs (`list[Dict]`, *optional*): Optional, only returned when auxilary losses are activated (i.e. `config.auxiliary_loss` is set to `True`) and labels are provided. It is a list of dictionaries containing the two above keys (`logits` and `pred_boxes`) for each decoder layer. last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): Sequence of hidden-states at the output of the last layer of the decoder of the model. hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): Tuple of `torch.FloatTensor` (one for the output of the embeddings, if the model has an embedding layer, + one for the output of each layer) of shape `(batch_size, sequence_length, hidden_size)`. Hidden-states of the model at the output of each layer plus the optional initial embedding outputs. attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, sequence_length)`. Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads. """ loss: Optional[torch.FloatTensor] = None loss_dict: Optional[Dict] = None logits: torch.FloatTensor = None pred_boxes: torch.FloatTensor = None auxiliary_outputs: Optional[List[Dict]] = None last_hidden_state: Optional[torch.FloatTensor] = None hidden_states: Optional[Tuple[torch.FloatTensor]] = None attentions: Optional[Tuple[torch.FloatTensor]] = None class YolosEmbeddings(nn.Module): """ Construct the CLS token, detection tokens, position and patch embeddings. """ def __init__(self, config: YolosConfig) -> None: super().__init__() self.cls_token = nn.Parameter(torch.zeros(1, 1, config.hidden_size)) self.detection_tokens = nn.Parameter(torch.zeros(1, config.num_detection_tokens, config.hidden_size)) self.patch_embeddings = YolosPatchEmbeddings(config) num_patches = self.patch_embeddings.num_patches self.position_embeddings = nn.Parameter( torch.zeros(1, num_patches + config.num_detection_tokens + 1, config.hidden_size) ) self.dropout = nn.Dropout(config.hidden_dropout_prob) self.interpolation = InterpolateInitialPositionEmbeddings(config) self.config = config def forward(self, pixel_values: torch.Tensor) -> torch.Tensor: batch_size, num_channels, height, width = pixel_values.shape embeddings = self.patch_embeddings(pixel_values) batch_size, seq_len, _ = embeddings.size() # add the [CLS] and detection tokens to the embedded patch tokens cls_tokens = self.cls_token.expand(batch_size, -1, -1) detection_tokens = self.detection_tokens.expand(batch_size, -1, -1) embeddings = torch.cat((cls_tokens, embeddings, detection_tokens), dim=1) # add positional encoding to each token # this might require interpolation of the existing position embeddings position_embeddings = self.interpolation(self.position_embeddings, (height, width)) embeddings = embeddings + position_embeddings embeddings = self.dropout(embeddings) return embeddings class InterpolateInitialPositionEmbeddings(nn.Module): def __init__(self, config) -> None: super().__init__() self.config = config def forward(self, pos_embed, img_size=(800, 1344)) -> torch.Tensor: cls_pos_embed = pos_embed[:, 0, :] cls_pos_embed = cls_pos_embed[:, None] det_pos_embed = pos_embed[:, -self.config.num_detection_tokens :, :] patch_pos_embed = pos_embed[:, 1 : -self.config.num_detection_tokens, :] patch_pos_embed = patch_pos_embed.transpose(1, 2) batch_size, hidden_size, seq_len = patch_pos_embed.shape patch_height, patch_width = ( self.config.image_size[0] // self.config.patch_size, self.config.image_size[1] // self.config.patch_size, ) patch_pos_embed = patch_pos_embed.view(batch_size, hidden_size, patch_height, patch_width) height, width = img_size new_patch_heigth, new_patch_width = height // self.config.patch_size, width // self.config.patch_size patch_pos_embed = nn.functional.interpolate( patch_pos_embed, size=(new_patch_heigth, new_patch_width), mode="bicubic", align_corners=False ) patch_pos_embed = patch_pos_embed.flatten(2).transpose(1, 2) scale_pos_embed = torch.cat((cls_pos_embed, patch_pos_embed, det_pos_embed), dim=1) return scale_pos_embed class InterpolateMidPositionEmbeddings(nn.Module): def __init__(self, config) -> None: super().__init__() self.config = config def forward(self, pos_embed, img_size=(800, 1344)) -> torch.Tensor: cls_pos_embed = pos_embed[:, :, 0, :] cls_pos_embed = cls_pos_embed[:, None] det_pos_embed = pos_embed[:, :, -self.config.num_detection_tokens :, :] patch_pos_embed = pos_embed[:, :, 1 : -self.config.num_detection_tokens, :] patch_pos_embed = patch_pos_embed.transpose(2, 3) depth, batch_size, hidden_size, seq_len = patch_pos_embed.shape patch_height, patch_width = ( self.config.image_size[0] // self.config.patch_size, self.config.image_size[1] // self.config.patch_size, ) patch_pos_embed = patch_pos_embed.view(depth * batch_size, hidden_size, patch_height, patch_width) height, width = img_size new_patch_height, new_patch_width = height // self.config.patch_size, width // self.config.patch_size patch_pos_embed = nn.functional.interpolate( patch_pos_embed, size=(new_patch_height, new_patch_width), mode="bicubic", align_corners=False ) patch_pos_embed = ( patch_pos_embed.flatten(2) .transpose(1, 2) .contiguous() .view(depth, batch_size, new_patch_height * new_patch_width, hidden_size) ) scale_pos_embed = torch.cat((cls_pos_embed, patch_pos_embed, det_pos_embed), dim=2) return scale_pos_embed class YolosPatchEmbeddings(nn.Module): """ This class turns `pixel_values` of shape `(batch_size, num_channels, height, width)` into the initial `hidden_states` (patch embeddings) of shape `(batch_size, seq_length, hidden_size)` to be consumed by a Transformer. """ def __init__(self, config): super().__init__() image_size, patch_size = config.image_size, config.patch_size num_channels, hidden_size = config.num_channels, config.hidden_size image_size = image_size if isinstance(image_size, collections.abc.Iterable) else (image_size, image_size) patch_size = patch_size if isinstance(patch_size, collections.abc.Iterable) else (patch_size, patch_size) num_patches = (image_size[1] // patch_size[1]) * (image_size[0] // patch_size[0]) self.image_size = image_size self.patch_size = patch_size self.num_channels = num_channels self.num_patches = num_patches self.projection = nn.Conv2d(num_channels, hidden_size, kernel_size=patch_size, stride=patch_size) def forward(self, pixel_values: torch.Tensor) -> torch.Tensor: batch_size, num_channels, height, width = pixel_values.shape if num_channels != self.num_channels: raise ValueError( "Make sure that the channel dimension of the pixel values match with the one set in the configuration." ) embeddings = self.projection(pixel_values).flatten(2).transpose(1, 2) return embeddings # Copied from transformers.models.vit.modeling_vit.ViTSelfAttention with ViT->Yolos class YolosSelfAttention(nn.Module): def __init__(self, config: YolosConfig) -> None: super().__init__() if config.hidden_size % config.num_attention_heads != 0 and not hasattr(config, "embedding_size"): raise ValueError( f"The hidden size {config.hidden_size,} is not a multiple of the number of attention " f"heads {config.num_attention_heads}." ) self.num_attention_heads = config.num_attention_heads self.attention_head_size = int(config.hidden_size / config.num_attention_heads) self.all_head_size = self.num_attention_heads * self.attention_head_size self.query = nn.Linear(config.hidden_size, self.all_head_size, bias=config.qkv_bias) self.key = nn.Linear(config.hidden_size, self.all_head_size, bias=config.qkv_bias) self.value = nn.Linear(config.hidden_size, self.all_head_size, bias=config.qkv_bias) self.dropout = nn.Dropout(config.attention_probs_dropout_prob) def transpose_for_scores(self, x: torch.Tensor) -> torch.Tensor: new_x_shape = x.size()[:-1] + (self.num_attention_heads, self.attention_head_size) x = x.view(new_x_shape) return x.permute(0, 2, 1, 3) def forward( self, hidden_states, head_mask: Optional[torch.Tensor] = None, output_attentions: bool = False ) -> Union[Tuple[torch.Tensor, torch.Tensor], Tuple[torch.Tensor]]: mixed_query_layer = self.query(hidden_states) key_layer = self.transpose_for_scores(self.key(hidden_states)) value_layer = self.transpose_for_scores(self.value(hidden_states)) query_layer = self.transpose_for_scores(mixed_query_layer) # Take the dot product between "query" and "key" to get the raw attention scores. attention_scores = torch.matmul(query_layer, key_layer.transpose(-1, -2)) attention_scores = attention_scores / math.sqrt(self.attention_head_size) # Normalize the attention scores to probabilities. attention_probs = nn.functional.softmax(attention_scores, dim=-1) # This is actually dropping out entire tokens to attend to, which might # seem a bit unusual, but is taken from the original Transformer paper. attention_probs = self.dropout(attention_probs) # Mask heads if we want to if head_mask is not None: attention_probs = attention_probs * head_mask context_layer = torch.matmul(attention_probs, value_layer) context_layer = context_layer.permute(0, 2, 1, 3).contiguous() new_context_layer_shape = context_layer.size()[:-2] + (self.all_head_size,) context_layer = context_layer.view(new_context_layer_shape) outputs = (context_layer, attention_probs) if output_attentions else (context_layer,) return outputs # Copied from transformers.models.vit.modeling_vit.ViTSelfOutput with ViT->Yolos class YolosSelfOutput(nn.Module): """ The residual connection is defined in YolosLayer instead of here (as is the case with other models), due to the layernorm applied before each block. """ def __init__(self, config: YolosConfig) -> None: super().__init__() self.dense = nn.Linear(config.hidden_size, config.hidden_size) self.dropout = nn.Dropout(config.hidden_dropout_prob) def forward(self, hidden_states: torch.Tensor, input_tensor: torch.Tensor) -> torch.Tensor: hidden_states = self.dense(hidden_states) hidden_states = self.dropout(hidden_states) return hidden_states # Copied from transformers.models.vit.modeling_vit.ViTAttention with ViT->Yolos class YolosAttention(nn.Module): def __init__(self, config: YolosConfig) -> None: super().__init__() self.attention = YolosSelfAttention(config) self.output = YolosSelfOutput(config) self.pruned_heads = set() def prune_heads(self, heads: Set[int]) -> None: if len(heads) == 0: return heads, index = find_pruneable_heads_and_indices( heads, self.attention.num_attention_heads, self.attention.attention_head_size, self.pruned_heads ) # Prune linear layers self.attention.query = prune_linear_layer(self.attention.query, index) self.attention.key = prune_linear_layer(self.attention.key, index) self.attention.value = prune_linear_layer(self.attention.value, index) self.output.dense = prune_linear_layer(self.output.dense, index, dim=1) # Update hyper params and store pruned heads self.attention.num_attention_heads = self.attention.num_attention_heads - len(heads) self.attention.all_head_size = self.attention.attention_head_size * self.attention.num_attention_heads self.pruned_heads = self.pruned_heads.union(heads) def forward( self, hidden_states: torch.Tensor, head_mask: Optional[torch.Tensor] = None, output_attentions: bool = False, ) -> Union[Tuple[torch.Tensor, torch.Tensor], Tuple[torch.Tensor]]: self_outputs = self.attention(hidden_states, head_mask, output_attentions) attention_output = self.output(self_outputs[0], hidden_states) outputs = (attention_output,) + self_outputs[1:] # add attentions if we output them return outputs # Copied from transformers.models.vit.modeling_vit.ViTIntermediate with ViT->Yolos class YolosIntermediate(nn.Module): def __init__(self, config: YolosConfig) -> None: super().__init__() self.dense = nn.Linear(config.hidden_size, config.intermediate_size) if isinstance(config.hidden_act, str): self.intermediate_act_fn = ACT2FN[config.hidden_act] else: self.intermediate_act_fn = config.hidden_act def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: hidden_states = self.dense(hidden_states) hidden_states = self.intermediate_act_fn(hidden_states) return hidden_states # Copied from transformers.models.vit.modeling_vit.ViTOutput with ViT->Yolos class YolosOutput(nn.Module): def __init__(self, config: YolosConfig) -> None: super().__init__() self.dense = nn.Linear(config.intermediate_size, config.hidden_size) self.dropout = nn.Dropout(config.hidden_dropout_prob) def forward(self, hidden_states: torch.Tensor, input_tensor: torch.Tensor) -> torch.Tensor: hidden_states = self.dense(hidden_states) hidden_states = self.dropout(hidden_states) hidden_states = hidden_states + input_tensor return hidden_states # Copied from transformers.models.vit.modeling_vit.ViTLayer with ViT->Yolos class YolosLayer(nn.Module): """This corresponds to the Block class in the timm implementation.""" def __init__(self, config: YolosConfig) -> None: super().__init__() self.chunk_size_feed_forward = config.chunk_size_feed_forward self.seq_len_dim = 1 self.attention = YolosAttention(config) self.intermediate = YolosIntermediate(config) self.output = YolosOutput(config) self.layernorm_before = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) self.layernorm_after = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) def forward( self, hidden_states: torch.Tensor, head_mask: Optional[torch.Tensor] = None, output_attentions: bool = False, ) -> Union[Tuple[torch.Tensor, torch.Tensor], Tuple[torch.Tensor]]: self_attention_outputs = self.attention( self.layernorm_before(hidden_states), # in Yolos, layernorm is applied before self-attention head_mask, output_attentions=output_attentions, ) attention_output = self_attention_outputs[0] outputs = self_attention_outputs[1:] # add self attentions if we output attention weights # first residual connection hidden_states = attention_output + hidden_states # in Yolos, layernorm is also applied after self-attention layer_output = self.layernorm_after(hidden_states) layer_output = self.intermediate(layer_output) # second residual connection is done here layer_output = self.output(layer_output, hidden_states) outputs = (layer_output,) + outputs return outputs class YolosEncoder(nn.Module): def __init__(self, config: YolosConfig) -> None: super().__init__() self.config = config self.layer = nn.ModuleList([YolosLayer(config) for _ in range(config.num_hidden_layers)]) self.gradient_checkpointing = False seq_length = ( 1 + (config.image_size[0] * config.image_size[1] // config.patch_size**2) + config.num_detection_tokens ) self.mid_position_embeddings = ( nn.Parameter( torch.zeros( config.num_hidden_layers - 1, 1, seq_length, config.hidden_size, ) ) if config.use_mid_position_embeddings else None ) self.interpolation = InterpolateMidPositionEmbeddings(config) if config.use_mid_position_embeddings else None def forward( self, hidden_states: torch.Tensor, height, width, head_mask: Optional[torch.Tensor] = None, output_attentions: bool = False, output_hidden_states: bool = False, return_dict: bool = True, ) -> Union[tuple, BaseModelOutput]: all_hidden_states = () if output_hidden_states else None all_self_attentions = () if output_attentions else None if self.config.use_mid_position_embeddings: interpolated_mid_position_embeddings = self.interpolation(self.mid_position_embeddings, (height, width)) for i, layer_module in enumerate(self.layer): if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) layer_head_mask = head_mask[i] if head_mask is not None else None if self.gradient_checkpointing and self.training: def create_custom_forward(module): def custom_forward(*inputs): return module(*inputs, output_attentions) return custom_forward layer_outputs = torch.utils.checkpoint.checkpoint( create_custom_forward(layer_module), hidden_states, layer_head_mask, ) else: layer_outputs = layer_module(hidden_states, layer_head_mask, output_attentions) hidden_states = layer_outputs[0] if self.config.use_mid_position_embeddings: if i < (self.config.num_hidden_layers - 1): hidden_states = hidden_states + interpolated_mid_position_embeddings[i] if output_attentions: all_self_attentions = all_self_attentions + (layer_outputs[1],) if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) if not return_dict: return tuple(v for v in [hidden_states, all_hidden_states, all_self_attentions] if v is not None) return BaseModelOutput( last_hidden_state=hidden_states, hidden_states=all_hidden_states, attentions=all_self_attentions, ) class YolosPreTrainedModel(PreTrainedModel): """ An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained models. """ config_class = YolosConfig base_model_prefix = "vit" main_input_name = "pixel_values" supports_gradient_checkpointing = True def _init_weights(self, module: Union[nn.Linear, nn.Conv2d, nn.LayerNorm]) -> None: """Initialize the weights""" if isinstance(module, (nn.Linear, nn.Conv2d)): # Slightly different from the TF version which uses truncated_normal for initialization # cf https://github.com/pytorch/pytorch/pull/5617 module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) if module.bias is not None: module.bias.data.zero_() elif isinstance(module, nn.LayerNorm): module.bias.data.zero_() module.weight.data.fill_(1.0) def _set_gradient_checkpointing(self, module: YolosEncoder, value: bool = False) -> None: if isinstance(module, YolosEncoder): module.gradient_checkpointing = value YOLOS_START_DOCSTRING = r""" This model is a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#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. Parameters: config ([`YolosConfig`]): 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 [`~PreTrainedModel.from_pretrained`] method to load the model weights. """ YOLOS_INPUTS_DOCSTRING = r""" Args: pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`): Pixel values. Pixel values can be obtained using [`AutoImageProcessor`]. See [`YolosImageProcessor.__call__`] for details. head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*): Mask to nullify selected heads of the self-attention modules. Mask values selected in `[0, 1]`: - 1 indicates the head is **not masked**, - 0 indicates the head is **masked**. output_attentions (`bool`, *optional*): Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned tensors for more detail. output_hidden_states (`bool`, *optional*): Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for more detail. return_dict (`bool`, *optional*): Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. """ @add_start_docstrings( "The bare YOLOS Model transformer outputting raw hidden-states without any specific head on top.", YOLOS_START_DOCSTRING, ) class YolosModel(YolosPreTrainedModel): def __init__(self, config: YolosConfig, add_pooling_layer: bool = True): super().__init__(config) self.config = config self.embeddings = YolosEmbeddings(config) self.encoder = YolosEncoder(config) self.layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) self.pooler = YolosPooler(config) if add_pooling_layer else None # Initialize weights and apply final processing self.post_init() def get_input_embeddings(self) -> YolosPatchEmbeddings: return self.embeddings.patch_embeddings def _prune_heads(self, heads_to_prune: Dict[int, List[int]]) -> None: """ Prunes heads of the model. Args: heads_to_prune (`dict` of {layer_num: list of heads to prune in this layer}): See base class `PreTrainedModel`. """ for layer, heads in heads_to_prune.items(): self.encoder.layer[layer].attention.prune_heads(heads) @add_start_docstrings_to_model_forward(YOLOS_INPUTS_DOCSTRING) @add_code_sample_docstrings( checkpoint=_CHECKPOINT_FOR_DOC, output_type=BaseModelOutputWithPooling, config_class=_CONFIG_FOR_DOC, modality="vision", expected_output=_EXPECTED_OUTPUT_SHAPE, ) def forward( self, pixel_values: Optional[torch.Tensor] = None, head_mask: Optional[torch.Tensor] = None, output_attentions: Optional[bool] = None, output_hidden_states: Optional[bool] = None, return_dict: Optional[bool] = None, ) -> Union[Tuple, BaseModelOutputWithPooling]: output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions output_hidden_states = ( output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states ) return_dict = return_dict if return_dict is not None else self.config.use_return_dict if pixel_values is None: raise ValueError("You have to specify pixel_values") # Prepare head mask if needed # 1.0 in head_mask indicate we keep the head # attention_probs has shape bsz x n_heads x N x N # input head_mask has shape [num_heads] or [num_hidden_layers x num_heads] # and head_mask is converted to shape [num_hidden_layers x batch x num_heads x seq_length x seq_length] head_mask = self.get_head_mask(head_mask, self.config.num_hidden_layers) embedding_output = self.embeddings(pixel_values) encoder_outputs = self.encoder( embedding_output, height=pixel_values.shape[-2], width=pixel_values.shape[-1], head_mask=head_mask, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output = encoder_outputs[0] sequence_output = self.layernorm(sequence_output) pooled_output = self.pooler(sequence_output) if self.pooler is not None else None if not return_dict: head_outputs = (sequence_output, pooled_output) if pooled_output is not None else (sequence_output,) return head_outputs + encoder_outputs[1:] return BaseModelOutputWithPooling( last_hidden_state=sequence_output, pooler_output=pooled_output, hidden_states=encoder_outputs.hidden_states, attentions=encoder_outputs.attentions, ) class YolosPooler(nn.Module): def __init__(self, config: YolosConfig): super().__init__() self.dense = nn.Linear(config.hidden_size, config.hidden_size) self.activation = nn.Tanh() def forward(self, hidden_states): # We "pool" the model by simply taking the hidden state corresponding # to the first token. first_token_tensor = hidden_states[:, 0] pooled_output = self.dense(first_token_tensor) pooled_output = self.activation(pooled_output) return pooled_output @add_start_docstrings( """ YOLOS Model (consisting of a ViT encoder) with object detection heads on top, for tasks such as COCO detection. """, YOLOS_START_DOCSTRING, ) class YolosForObjectDetection(YolosPreTrainedModel): def __init__(self, config: YolosConfig): super().__init__(config) # YOLOS (ViT) encoder model self.vit = YolosModel(config, add_pooling_layer=False) # Object detection heads # We add one for the "no object" class self.class_labels_classifier = YolosMLPPredictionHead( input_dim=config.hidden_size, hidden_dim=config.hidden_size, output_dim=config.num_labels + 1, num_layers=3 ) self.bbox_predictor = YolosMLPPredictionHead( input_dim=config.hidden_size, hidden_dim=config.hidden_size, output_dim=4, num_layers=3 ) # Initialize weights and apply final processing self.post_init() # taken from https://github.com/facebookresearch/detr/blob/master/models/detr.py @torch.jit.unused def _set_aux_loss(self, outputs_class, outputs_coord): # this is a workaround to make torchscript happy, as torchscript # doesn't support dictionary with non-homogeneous values, such # as a dict having both a Tensor and a list. return [{"logits": a, "pred_boxes": b} for a, b in zip(outputs_class[:-1], outputs_coord[:-1])] @add_start_docstrings_to_model_forward(YOLOS_INPUTS_DOCSTRING) @replace_return_docstrings(output_type=YolosObjectDetectionOutput, config_class=_CONFIG_FOR_DOC) def forward( self, pixel_values: torch.FloatTensor, labels: Optional[List[Dict]] = None, output_attentions: Optional[bool] = None, output_hidden_states: Optional[bool] = None, return_dict: Optional[bool] = None, ) -> Union[Tuple, YolosObjectDetectionOutput]: r""" labels (`List[Dict]` of len `(batch_size,)`, *optional*): Labels for computing the bipartite matching loss. List of dicts, each dictionary containing at least the following 2 keys: `'class_labels'` and `'boxes'` (the class labels and bounding boxes of an image in the batch respectively). The class labels themselves should be a `torch.LongTensor` of len `(number of bounding boxes in the image,)` and the boxes a `torch.FloatTensor` of shape `(number of bounding boxes in the image, 4)`. Returns: Examples: ```python >>> from transformers import AutoImageProcessor, AutoModelForObjectDetection >>> import torch >>> from PIL import Image >>> import requests >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg" >>> image = Image.open(requests.get(url, stream=True).raw) >>> image_processor = AutoImageProcessor.from_pretrained("hustvl/yolos-tiny") >>> model = AutoModelForObjectDetection.from_pretrained("hustvl/yolos-tiny") >>> inputs = image_processor(images=image, return_tensors="pt") >>> outputs = model(**inputs) >>> # convert outputs (bounding boxes and class logits) to COCO API >>> target_sizes = torch.tensor([image.size[::-1]]) >>> results = image_processor.post_process_object_detection(outputs, threshold=0.9, target_sizes=target_sizes)[ ... 0 ... ] >>> for score, label, box in zip(results["scores"], results["labels"], results["boxes"]): ... box = [round(i, 2) for i in box.tolist()] ... print( ... f"Detected {model.config.id2label[label.item()]} with confidence " ... f"{round(score.item(), 3)} at location {box}" ... ) Detected remote with confidence 0.994 at location [46.96, 72.61, 181.02, 119.73] Detected remote with confidence 0.975 at location [340.66, 79.19, 372.59, 192.65] Detected cat with confidence 0.984 at location [12.27, 54.25, 319.42, 470.99] Detected remote with confidence 0.922 at location [41.66, 71.96, 178.7, 120.33] Detected cat with confidence 0.914 at location [342.34, 21.48, 638.64, 372.46] ```""" return_dict = return_dict if return_dict is not None else self.config.use_return_dict # First, sent images through YOLOS base model to obtain hidden states outputs = self.vit( pixel_values, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output = outputs[0] # Take the final hidden states of the detection tokens sequence_output = sequence_output[:, -self.config.num_detection_tokens :, :] # Class logits + predicted bounding boxes logits = self.class_labels_classifier(sequence_output) pred_boxes = self.bbox_predictor(sequence_output).sigmoid() loss, loss_dict, auxiliary_outputs = None, None, None if labels is not None: # First: create the matcher matcher = YolosHungarianMatcher( class_cost=self.config.class_cost, bbox_cost=self.config.bbox_cost, giou_cost=self.config.giou_cost ) # Second: create the criterion losses = ["labels", "boxes", "cardinality"] criterion = YolosLoss( matcher=matcher, num_classes=self.config.num_labels, eos_coef=self.config.eos_coefficient, losses=losses, ) criterion.to(self.device) # Third: compute the losses, based on outputs and labels outputs_loss = {} outputs_loss["logits"] = logits outputs_loss["pred_boxes"] = pred_boxes if self.config.auxiliary_loss: intermediate = outputs.intermediate_hidden_states if return_dict else outputs[4] outputs_class = self.class_labels_classifier(intermediate) outputs_coord = self.bbox_predictor(intermediate).sigmoid() auxiliary_outputs = self._set_aux_loss(outputs_class, outputs_coord) outputs_loss["auxiliary_outputs"] = auxiliary_outputs loss_dict = criterion(outputs_loss, labels) # Fourth: compute total loss, as a weighted sum of the various losses weight_dict = {"loss_ce": 1, "loss_bbox": self.config.bbox_loss_coefficient} weight_dict["loss_giou"] = self.config.giou_loss_coefficient if self.config.auxiliary_loss: aux_weight_dict = {} for i in range(self.config.decoder_layers - 1): aux_weight_dict.update({k + f"_{i}": v for k, v in weight_dict.items()}) weight_dict.update(aux_weight_dict) loss = sum(loss_dict[k] * weight_dict[k] for k in loss_dict.keys() if k in weight_dict) if not return_dict: if auxiliary_outputs is not None: output = (logits, pred_boxes) + auxiliary_outputs + outputs else: output = (logits, pred_boxes) + outputs return ((loss, loss_dict) + output) if loss is not None else output return YolosObjectDetectionOutput( loss=loss, loss_dict=loss_dict, logits=logits, pred_boxes=pred_boxes, auxiliary_outputs=auxiliary_outputs, last_hidden_state=outputs.last_hidden_state, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) # Copied from transformers.models.detr.modeling_detr.dice_loss def dice_loss(inputs, targets, num_boxes): """ Compute the DICE loss, similar to generalized IOU for masks Args: inputs: A float tensor of arbitrary shape. The predictions for each example. targets: A float tensor with the same shape as inputs. Stores the binary classification label for each element in inputs (0 for the negative class and 1 for the positive class). """ inputs = inputs.sigmoid() inputs = inputs.flatten(1) numerator = 2 * (inputs * targets).sum(1) denominator = inputs.sum(-1) + targets.sum(-1) loss = 1 - (numerator + 1) / (denominator + 1) return loss.sum() / num_boxes # Copied from transformers.models.detr.modeling_detr.sigmoid_focal_loss def sigmoid_focal_loss(inputs, targets, num_boxes, alpha: float = 0.25, gamma: float = 2): """ Loss used in RetinaNet for dense detection: https://arxiv.org/abs/1708.02002. Args: inputs (`torch.FloatTensor` of arbitrary shape): The predictions for each example. targets (`torch.FloatTensor` with the same shape as `inputs`) A tensor storing the binary classification label for each element in the `inputs` (0 for the negative class and 1 for the positive class). alpha (`float`, *optional*, defaults to `0.25`): Optional weighting factor in the range (0,1) to balance positive vs. negative examples. gamma (`int`, *optional*, defaults to `2`): Exponent of the modulating factor (1 - p_t) to balance easy vs hard examples. Returns: Loss tensor """ prob = inputs.sigmoid() ce_loss = nn.functional.binary_cross_entropy_with_logits(inputs, targets, reduction="none") # add modulating factor p_t = prob * targets + (1 - prob) * (1 - targets) loss = ce_loss * ((1 - p_t) ** gamma) if alpha >= 0: alpha_t = alpha * targets + (1 - alpha) * (1 - targets) loss = alpha_t * loss return loss.mean(1).sum() / num_boxes # Copied from transformers.models.detr.modeling_detr.DetrLoss with Detr->Yolos class YolosLoss(nn.Module): """ This class computes the losses for YolosForObjectDetection/YolosForSegmentation. The process happens in two steps: 1) we compute hungarian assignment between ground truth boxes and the outputs of the model 2) we supervise each pair of matched ground-truth / prediction (supervise class and box). A note on the `num_classes` argument (copied from original repo in detr.py): "the naming of the `num_classes` parameter of the criterion is somewhat misleading. It indeed corresponds to `max_obj_id` + 1, where `max_obj_id` is the maximum id for a class in your dataset. For example, COCO has a `max_obj_id` of 90, so we pass `num_classes` to be 91. As another example, for a dataset that has a single class with `id` 1, you should pass `num_classes` to be 2 (`max_obj_id` + 1). For more details on this, check the following discussion https://github.com/facebookresearch/detr/issues/108#issuecomment-650269223" Args: matcher (`YolosHungarianMatcher`): Module able to compute a matching between targets and proposals. num_classes (`int`): Number of object categories, omitting the special no-object category. eos_coef (`float`): Relative classification weight applied to the no-object category. losses (`List[str]`): List of all the losses to be applied. See `get_loss` for a list of all available losses. """ def __init__(self, matcher, num_classes, eos_coef, losses): super().__init__() self.matcher = matcher self.num_classes = num_classes self.eos_coef = eos_coef self.losses = losses empty_weight = torch.ones(self.num_classes + 1) empty_weight[-1] = self.eos_coef self.register_buffer("empty_weight", empty_weight) # removed logging parameter, which was part of the original implementation def loss_labels(self, outputs, targets, indices, num_boxes): """ Classification loss (NLL) targets dicts must contain the key "class_labels" containing a tensor of dim [nb_target_boxes] """ if "logits" not in outputs: raise KeyError("No logits were found in the outputs") source_logits = outputs["logits"] idx = self._get_source_permutation_idx(indices) target_classes_o = torch.cat([t["class_labels"][J] for t, (_, J) in zip(targets, indices)]) target_classes = torch.full( source_logits.shape[:2], self.num_classes, dtype=torch.int64, device=source_logits.device ) target_classes[idx] = target_classes_o loss_ce = nn.functional.cross_entropy(source_logits.transpose(1, 2), target_classes, self.empty_weight) losses = {"loss_ce": loss_ce} return losses @torch.no_grad() def loss_cardinality(self, outputs, targets, indices, num_boxes): """ Compute the cardinality error, i.e. the absolute error in the number of predicted non-empty boxes. This is not really a loss, it is intended for logging purposes only. It doesn't propagate gradients. """ logits = outputs["logits"] device = logits.device target_lengths = torch.as_tensor([len(v["class_labels"]) for v in targets], device=device) # Count the number of predictions that are NOT "no-object" (which is the last class) card_pred = (logits.argmax(-1) != logits.shape[-1] - 1).sum(1) card_err = nn.functional.l1_loss(card_pred.float(), target_lengths.float()) losses = {"cardinality_error": card_err} return losses def loss_boxes(self, outputs, targets, indices, num_boxes): """ Compute the losses related to the bounding boxes, the L1 regression loss and the GIoU loss. Targets dicts must contain the key "boxes" containing a tensor of dim [nb_target_boxes, 4]. The target boxes are expected in format (center_x, center_y, w, h), normalized by the image size. """ if "pred_boxes" not in outputs: raise KeyError("No predicted boxes found in outputs") idx = self._get_source_permutation_idx(indices) source_boxes = outputs["pred_boxes"][idx] target_boxes = torch.cat([t["boxes"][i] for t, (_, i) in zip(targets, indices)], dim=0) loss_bbox = nn.functional.l1_loss(source_boxes, target_boxes, reduction="none") losses = {} losses["loss_bbox"] = loss_bbox.sum() / num_boxes loss_giou = 1 - torch.diag( generalized_box_iou(center_to_corners_format(source_boxes), center_to_corners_format(target_boxes)) ) losses["loss_giou"] = loss_giou.sum() / num_boxes return losses def loss_masks(self, outputs, targets, indices, num_boxes): """ Compute the losses related to the masks: the focal loss and the dice loss. Targets dicts must contain the key "masks" containing a tensor of dim [nb_target_boxes, h, w]. """ if "pred_masks" not in outputs: raise KeyError("No predicted masks found in outputs") source_idx = self._get_source_permutation_idx(indices) target_idx = self._get_target_permutation_idx(indices) source_masks = outputs["pred_masks"] source_masks = source_masks[source_idx] masks = [t["masks"] for t in targets] # TODO use valid to mask invalid areas due to padding in loss target_masks, valid = nested_tensor_from_tensor_list(masks).decompose() target_masks = target_masks.to(source_masks) target_masks = target_masks[target_idx] # upsample predictions to the target size source_masks = nn.functional.interpolate( source_masks[:, None], size=target_masks.shape[-2:], mode="bilinear", align_corners=False ) source_masks = source_masks[:, 0].flatten(1) target_masks = target_masks.flatten(1) target_masks = target_masks.view(source_masks.shape) losses = { "loss_mask": sigmoid_focal_loss(source_masks, target_masks, num_boxes), "loss_dice": dice_loss(source_masks, target_masks, num_boxes), } return losses def _get_source_permutation_idx(self, indices): # permute predictions following indices batch_idx = torch.cat([torch.full_like(source, i) for i, (source, _) in enumerate(indices)]) source_idx = torch.cat([source for (source, _) in indices]) return batch_idx, source_idx def _get_target_permutation_idx(self, indices): # permute targets following indices batch_idx = torch.cat([torch.full_like(target, i) for i, (_, target) in enumerate(indices)]) target_idx = torch.cat([target for (_, target) in indices]) return batch_idx, target_idx def get_loss(self, loss, outputs, targets, indices, num_boxes): loss_map = { "labels": self.loss_labels, "cardinality": self.loss_cardinality, "boxes": self.loss_boxes, "masks": self.loss_masks, } if loss not in loss_map: raise ValueError(f"Loss {loss} not supported") return loss_map[loss](outputs, targets, indices, num_boxes) def forward(self, outputs, targets): """ This performs the loss computation. Args: outputs (`dict`, *optional*): Dictionary of tensors, see the output specification of the model for the format. targets (`List[dict]`, *optional*): List of dicts, such that `len(targets) == batch_size`. The expected keys in each dict depends on the losses applied, see each loss' doc. """ outputs_without_aux = {k: v for k, v in outputs.items() if k != "auxiliary_outputs"} # Retrieve the matching between the outputs of the last layer and the targets indices = self.matcher(outputs_without_aux, targets) # Compute the average number of target boxes across all nodes, for normalization purposes num_boxes = sum(len(t["class_labels"]) for t in targets) num_boxes = torch.as_tensor([num_boxes], dtype=torch.float, device=next(iter(outputs.values())).device) # (Niels): comment out function below, distributed training to be added # if is_dist_avail_and_initialized(): # torch.distributed.all_reduce(num_boxes) # (Niels) in original implementation, num_boxes is divided by get_world_size() num_boxes = torch.clamp(num_boxes, min=1).item() # Compute all the requested losses losses = {} for loss in self.losses: losses.update(self.get_loss(loss, outputs, targets, indices, num_boxes)) # In case of auxiliary losses, we repeat this process with the output of each intermediate layer. if "auxiliary_outputs" in outputs: for i, auxiliary_outputs in enumerate(outputs["auxiliary_outputs"]): indices = self.matcher(auxiliary_outputs, targets) for loss in self.losses: if loss == "masks": # Intermediate masks losses are too costly to compute, we ignore them. continue l_dict = self.get_loss(loss, auxiliary_outputs, targets, indices, num_boxes) l_dict = {k + f"_{i}": v for k, v in l_dict.items()} losses.update(l_dict) return losses # Copied from transformers.models.detr.modeling_detr.DetrMLPPredictionHead with Detr->Yolos class YolosMLPPredictionHead(nn.Module): """ Very simple multi-layer perceptron (MLP, also called FFN), used to predict the normalized center coordinates, height and width of a bounding box w.r.t. an image. Copied from https://github.com/facebookresearch/detr/blob/master/models/detr.py """ def __init__(self, input_dim, hidden_dim, output_dim, num_layers): super().__init__() self.num_layers = num_layers h = [hidden_dim] * (num_layers - 1) self.layers = nn.ModuleList(nn.Linear(n, k) for n, k in zip([input_dim] + h, h + [output_dim])) def forward(self, x): for i, layer in enumerate(self.layers): x = nn.functional.relu(layer(x)) if i < self.num_layers - 1 else layer(x) return x # Copied from transformers.models.detr.modeling_detr.DetrHungarianMatcher with Detr->Yolos class YolosHungarianMatcher(nn.Module): """ This class computes an assignment between the targets and the predictions of the network. For efficiency reasons, the targets don't include the no_object. Because of this, in general, there are more predictions than targets. In this case, we do a 1-to-1 matching of the best predictions, while the others are un-matched (and thus treated as non-objects). Args: class_cost: The relative weight of the classification error in the matching cost. bbox_cost: The relative weight of the L1 error of the bounding box coordinates in the matching cost. giou_cost: The relative weight of the giou loss of the bounding box in the matching cost. """ def __init__(self, class_cost: float = 1, bbox_cost: float = 1, giou_cost: float = 1): super().__init__() requires_backends(self, ["scipy"]) self.class_cost = class_cost self.bbox_cost = bbox_cost self.giou_cost = giou_cost if class_cost == 0 and bbox_cost == 0 and giou_cost == 0: raise ValueError("All costs of the Matcher can't be 0") @torch.no_grad() def forward(self, outputs, targets): """ Args: outputs (`dict`): A dictionary that contains at least these entries: * "logits": Tensor of dim [batch_size, num_queries, num_classes] with the classification logits * "pred_boxes": Tensor of dim [batch_size, num_queries, 4] with the predicted box coordinates. targets (`List[dict]`): A list of targets (len(targets) = batch_size), where each target is a dict containing: * "class_labels": Tensor of dim [num_target_boxes] (where num_target_boxes is the number of ground-truth objects in the target) containing the class labels * "boxes": Tensor of dim [num_target_boxes, 4] containing the target box coordinates. Returns: `List[Tuple]`: A list of size `batch_size`, containing tuples of (index_i, index_j) where: - index_i is the indices of the selected predictions (in order) - index_j is the indices of the corresponding selected targets (in order) For each batch element, it holds: len(index_i) = len(index_j) = min(num_queries, num_target_boxes) """ batch_size, num_queries = outputs["logits"].shape[:2] # We flatten to compute the cost matrices in a batch out_prob = outputs["logits"].flatten(0, 1).softmax(-1) # [batch_size * num_queries, num_classes] out_bbox = outputs["pred_boxes"].flatten(0, 1) # [batch_size * num_queries, 4] # Also concat the target labels and boxes target_ids = torch.cat([v["class_labels"] for v in targets]) target_bbox = torch.cat([v["boxes"] for v in targets]) # Compute the classification cost. Contrary to the loss, we don't use the NLL, # but approximate it in 1 - proba[target class]. # The 1 is a constant that doesn't change the matching, it can be ommitted. class_cost = -out_prob[:, target_ids] # Compute the L1 cost between boxes bbox_cost = torch.cdist(out_bbox, target_bbox, p=1) # Compute the giou cost between boxes giou_cost = -generalized_box_iou(center_to_corners_format(out_bbox), center_to_corners_format(target_bbox)) # Final cost matrix cost_matrix = self.bbox_cost * bbox_cost + self.class_cost * class_cost + self.giou_cost * giou_cost cost_matrix = cost_matrix.view(batch_size, num_queries, -1).cpu() sizes = [len(v["boxes"]) for v in targets] indices = [linear_sum_assignment(c[i]) for i, c in enumerate(cost_matrix.split(sizes, -1))] return [(torch.as_tensor(i, dtype=torch.int64), torch.as_tensor(j, dtype=torch.int64)) for i, j in indices] # Copied from transformers.models.detr.modeling_detr._upcast def _upcast(t: Tensor) -> Tensor: # Protects from numerical overflows in multiplications by upcasting to the equivalent higher type if t.is_floating_point(): return t if t.dtype in (torch.float32, torch.float64) else t.float() else: return t if t.dtype in (torch.int32, torch.int64) else t.int() # Copied from transformers.models.detr.modeling_detr.box_area def box_area(boxes: Tensor) -> Tensor: """ Computes the area of a set of bounding boxes, which are specified by its (x1, y1, x2, y2) coordinates. Args: boxes (`torch.FloatTensor` of shape `(number_of_boxes, 4)`): Boxes for which the area will be computed. They are expected to be in (x1, y1, x2, y2) format with `0 <= x1 < x2` and `0 <= y1 < y2`. Returns: `torch.FloatTensor`: a tensor containing the area for each box. """ boxes = _upcast(boxes) return (boxes[:, 2] - boxes[:, 0]) * (boxes[:, 3] - boxes[:, 1]) # Copied from transformers.models.detr.modeling_detr.box_iou def box_iou(boxes1, boxes2): area1 = box_area(boxes1) area2 = box_area(boxes2) left_top = torch.max(boxes1[:, None, :2], boxes2[:, :2]) # [N,M,2] right_bottom = torch.min(boxes1[:, None, 2:], boxes2[:, 2:]) # [N,M,2] width_height = (right_bottom - left_top).clamp(min=0) # [N,M,2] inter = width_height[:, :, 0] * width_height[:, :, 1] # [N,M] union = area1[:, None] + area2 - inter iou = inter / union return iou, union # Copied from transformers.models.detr.modeling_detr.generalized_box_iou def generalized_box_iou(boxes1, boxes2): """ Generalized IoU from https://giou.stanford.edu/. The boxes should be in [x0, y0, x1, y1] (corner) format. Returns: `torch.FloatTensor`: a [N, M] pairwise matrix, where N = len(boxes1) and M = len(boxes2) """ # degenerate boxes gives inf / nan results # so do an early check if not (boxes1[:, 2:] >= boxes1[:, :2]).all(): raise ValueError(f"boxes1 must be in [x0, y0, x1, y1] (corner) format, but got {boxes1}") if not (boxes2[:, 2:] >= boxes2[:, :2]).all(): raise ValueError(f"boxes2 must be in [x0, y0, x1, y1] (corner) format, but got {boxes2}") iou, union = box_iou(boxes1, boxes2) top_left = torch.min(boxes1[:, None, :2], boxes2[:, :2]) bottom_right = torch.max(boxes1[:, None, 2:], boxes2[:, 2:]) width_height = (bottom_right - top_left).clamp(min=0) # [N,M,2] area = width_height[:, :, 0] * width_height[:, :, 1] return iou - (area - union) / area # Copied from transformers.models.detr.modeling_detr._max_by_axis def _max_by_axis(the_list): # type: (List[List[int]]) -> List[int] maxes = the_list[0] for sublist in the_list[1:]: for index, item in enumerate(sublist): maxes[index] = max(maxes[index], item) return maxes # Copied from transformers.models.detr.modeling_detr.NestedTensor class NestedTensor(object): def __init__(self, tensors, mask: Optional[Tensor]): self.tensors = tensors self.mask = mask def to(self, device): cast_tensor = self.tensors.to(device) mask = self.mask if mask is not None: cast_mask = mask.to(device) else: cast_mask = None return NestedTensor(cast_tensor, cast_mask) def decompose(self): return self.tensors, self.mask def __repr__(self): return str(self.tensors) # Copied from transformers.models.detr.modeling_detr.nested_tensor_from_tensor_list def nested_tensor_from_tensor_list(tensor_list: List[Tensor]): if tensor_list[0].ndim == 3: max_size = _max_by_axis([list(img.shape) for img in tensor_list]) batch_shape = [len(tensor_list)] + max_size batch_size, num_channels, height, width = batch_shape dtype = tensor_list[0].dtype device = tensor_list[0].device tensor = torch.zeros(batch_shape, dtype=dtype, device=device) mask = torch.ones((batch_size, height, width), dtype=torch.bool, device=device) for img, pad_img, m in zip(tensor_list, tensor, mask): pad_img[: img.shape[0], : img.shape[1], : img.shape[2]].copy_(img) m[: img.shape[1], : img.shape[2]] = False else: raise ValueError("Only 3-dimensional tensors are supported") return NestedTensor(tensor, mask)