| <!--Copyright 2023 The HuggingFace 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. | |
| ⚠️ Note that this file is in Markdown but contain specific syntax for our doc-builder (similar to MDX) that may not be | |
| rendered properly in your Markdown viewer. | |
| --> | |
| # Backbone | |
| A backbone is a model used for feature extraction for higher level computer vision tasks such as object detection and image classification. Transformers provides an [`AutoBackbone`] class for initializing a Transformers backbone from pretrained model weights, and two utility classes: | |
| * [`~utils.BackboneMixin`] enables initializing a backbone from Transformers or [timm](https://hf.co/docs/timm/index) and includes functions for returning the output features and indices. | |
| * [`~utils.BackboneConfigMixin`] sets the output features and indices of the backbone configuration. | |
| [timm](https://hf.co/docs/timm/index) models are loaded with the [`TimmBackbone`] and [`TimmBackboneConfig`] classes. | |
| Backbones are supported for the following models: | |
| * [BEiT](..model_doc/beit) | |
| * [BiT](../model_doc/bit) | |
| * [ConvNet](../model_doc/convnext) | |
| * [ConvNextV2](../model_doc/convnextv2) | |
| * [DiNAT](..model_doc/dinat) | |
| * [DINOV2](../model_doc/dinov2) | |
| * [FocalNet](../model_doc/focalnet) | |
| * [MaskFormer](../model_doc/maskformer) | |
| * [NAT](../model_doc/nat) | |
| * [ResNet](../model_doc/resnet) | |
| * [Swin Transformer](../model_doc/swin) | |
| * [Swin Transformer v2](../model_doc/swinv2) | |
| * [ViTDet](../model_doc/vitdet) | |
| ## AutoBackbone | |
| [[autodoc]] AutoBackbone | |
| ## BackboneMixin | |
| [[autodoc]] utils.BackboneMixin | |
| ## BackboneConfigMixin | |
| [[autodoc]] utils.BackboneConfigMixin | |
| ## TimmBackbone | |
| [[autodoc]] models.timm_backbone.TimmBackbone | |
| ## TimmBackboneConfig | |
| [[autodoc]] models.timm_backbone.TimmBackboneConfig | |