transformers/docs/source/en/model_doc/yolos.md

YOLOS

Overview

The YOLOS model was proposed in You Only Look at One Sequence: Rethinking Transformer in Vision through Object Detection by Yuxin Fang, Bencheng Liao, Xinggang Wang, Jiemin Fang, Jiyang Qi, Rui Wu, Jianwei Niu, Wenyu Liu. YOLOS proposes to just leverage the plain Vision Transformer (ViT) for object detection, inspired by DETR. It turns out that a base-sized encoder-only Transformer can also achieve 42 AP on COCO, similar to DETR and much more complex frameworks such as Faster R-CNN.

The abstract from the paper is the following:

Can Transformer perform 2D object- and region-level recognition from a pure sequence-to-sequence perspective with minimal knowledge about the 2D spatial structure? To answer this question, we present You Only Look at One Sequence (YOLOS), a series of object detection models based on the vanilla Vision Transformer with the fewest possible modifications, region priors, as well as inductive biases of the target task. We find that YOLOS pre-trained on the mid-sized ImageNet-1k dataset only can already achieve quite competitive performance on the challenging COCO object detection benchmark, e.g., YOLOS-Base directly adopted from BERT-Base architecture can obtain 42.0 box AP on COCO val. We also discuss the impacts as well as limitations of current pre-train schemes and model scaling strategies for Transformer in vision through YOLOS.

YOLOS architecture. Taken from the original paper.

This model was contributed by nielsr. The original code can be found here.

Using Scaled Dot Product Attention (SDPA)

PyTorch includes a native scaled dot-product attention (SDPA) operator as part of torch.nn.functional. This function encompasses several implementations that can be applied depending on the inputs and the hardware in use. See the official documentation or the GPU Inference page for more information.

SDPA is used by default for torch>=2.1.1 when an implementation is available, but you may also set attn_implementation="sdpa" in from_pretrained() to explicitly request SDPA to be used.

from transformers import AutoModelForObjectDetection
model = AutoModelForObjectDetection.from_pretrained("hustvl/yolos-base", attn_implementation="sdpa", torch_dtype=torch.float16)
...

For the best speedups, we recommend loading the model in half-precision (e.g. torch.float16 or torch.bfloat16).

On a local benchmark (A100-40GB, PyTorch 2.3.0, OS Ubuntu 22.04) with float32 and hustvl/yolos-base model, we saw the following speedups during inference.

Batch size	Average inference time (ms), eager mode	Average inference time (ms), sdpa model	Speed up, Sdpa / Eager (x)
1	106	76	1.39
2	154	90	1.71
4	222	116	1.91
8	368	168	2.19

Resources

A list of official Hugging Face and community (indicated by 🌎) resources to help you get started with YOLOS.

• All example notebooks illustrating inference + fine-tuning [YolosForObjectDetection] on a custom dataset can be found here.
• Scripts for finetuning [YolosForObjectDetection] with [Trainer] or Accelerate can be found here.
• See also: Object detection task guide

If you're interested in submitting a resource to be included here, please feel free to open a Pull Request and we'll review it! The resource should ideally demonstrate something new instead of duplicating an existing resource.

Use [YolosImageProcessor] for preparing images (and optional targets) for the model. Contrary to DETR, YOLOS doesn't require a pixel_mask to be created.

YolosConfig

autodoc YolosConfig

YolosImageProcessor

autodoc YolosImageProcessor - preprocess - pad - post_process_object_detection

YolosFeatureExtractor

autodoc YolosFeatureExtractor - call - pad - post_process_object_detection

YolosModel

autodoc YolosModel - forward

YolosForObjectDetection

autodoc YolosForObjectDetection - forward