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Torchreid is a library for deep-learning person re-identification, written in PyTorch.

It features:

  • multi-GPU training
  • support both image- and video-reid
  • end-to-end training and evaluation
  • incredibly easy preparation of reid datasets
  • multi-dataset training
  • cross-dataset evaluation
  • standard protocol used by most research papers
  • highly extensible (easy to add models, datasets, training methods, etc.)
  • implementations of state-of-the-art deep reid models
  • access to pretrained reid models
  • advanced training techniques
  • visualization tools (tensorboard, ranks, etc.)



How-to instructions:

Model zoo:

Tech report:

You can find some research projects that are built on top of Torchreid here.

What's new

  • [Aug 2020] 1.3.3: Fixed bug in visrank (caused by not unpacking dsetid).
  • [Aug 2020] 1.3.2: Added _junk_pids to grid and prid. This avoids using mislabeled gallery images for training when setting combineall=True.
  • [Aug 2020] 1.3.0: (1) Added dsetid to the existing 3-tuple data source, resulting in (impath, pid, camid, dsetid). This variable denotes the dataset ID and is useful when combining multiple datasets for training (as a dataset indicator). E.g., when combining market1501 and cuhk03, the former will be assigned dsetid=0 while the latter will be assigned dsetid=1. (2) Added RandomDatasetSampler. Analogous to RandomDomainSampler, RandomDatasetSampler samples a certain number of images (batch_size // num_datasets) from each of specified datasets (the amount is determined by num_datasets).
  • [Aug 2020] 1.2.6: Added RandomDomainSampler (it samples num_cams cameras each with batch_size // num_cams images to form a mini-batch).
  • [Jun 2020] 1.2.5: (1) Dataloader's output from __getitem__ has been changed from list to dict. Previously, an element, e.g. image tensor, was fetched with imgs=data[0]. Now it should be obtained by imgs=data['img']. See this commit for detailed changes. (2) Added k_tfm as an option to image data loader, which allows data augmentation to be applied k_tfm times independently to an image. If k_tfm > 1, imgs=data['img'] returns a list with k_tfm image tensors.
  • [May 2020] Added the person attribute recognition code used in Omni-Scale Feature Learning for Person Re-Identification (ICCV'19). See projects/attribute_recognition/.
  • [May 2020] 1.2.1: Added a simple API for feature extraction (torchreid/utils/ See the documentation for the instruction.
  • [Apr 2020] Code for reproducing the experiments of deep mutual learning in the OSNet paper (Supp. B) has been released at projects/DML.
  • [Apr 2020] Upgraded to 1.2.0. The engine class has been made more model-agnostic to improve extensibility. See Engine and ImageSoftmaxEngine for more details. Credit to Dassl.pytorch.
  • [Dec 2019] Our OSNet paper has been updated, with additional experiments (in section B of the supplementary) showing some useful techniques for improving OSNet's performance in practice.
  • [Nov 2019] ImageDataManager can load training data from target datasets by setting load_train_targets=True, and the train-loader can be accessed with train_loader_t = datamanager.train_loader_t. This feature is useful for domain adaptation research.


Make sure conda is installed.

# cd to your preferred directory and clone this repo
git clone

# create environment
cd deep-person-reid/
conda create --name torchreid python=3.7
conda activate torchreid

# install dependencies
# make sure `which python` and `which pip` point to the correct path
pip install -r requirements.txt

# install torch and torchvision (select the proper cuda version to suit your machine)
conda install pytorch torchvision cudatoolkit=9.0 -c pytorch

# install torchreid (don't need to re-build it if you modify the source code)
python develop

Get started: 30 seconds to Torchreid

  1. Import torchreid
import torchreid
  1. Load data manager
datamanager =
    transforms=['random_flip', 'random_crop']

3 Build model, optimizer and lr_scheduler

model = torchreid.models.build_model(

model = model.cuda()

optimizer = torchreid.optim.build_optimizer(

scheduler = torchreid.optim.build_lr_scheduler(
  1. Build engine
engine = torchreid.engine.ImageSoftmaxEngine(
  1. Run training and test

A unified interface

In "deep-person-reid/scripts/", we provide a unified interface to train and test a model. See "scripts/" and "scripts/" for more details. The folder "configs/" contains some predefined configs which you can use as a starting point.

Below we provide an example to train and test OSNet (Zhou et al. ICCV'19). Assume PATH_TO_DATA is the directory containing reid datasets. The environmental variable CUDA_VISIBLE_DEVICES is omitted, which you need to specify if you have a pool of gpus and want to use a specific set of them.

Conventional setting

To train OSNet on Market1501, do

python scripts/ \
--config-file configs/im_osnet_x1_0_softmax_256x128_amsgrad_cosine.yaml \
--transforms random_flip random_erase \
--root $PATH_TO_DATA

The config file sets Market1501 as the default dataset. If you wanna use DukeMTMC-reID, do

python scripts/ \
--config-file configs/im_osnet_x1_0_softmax_256x128_amsgrad_cosine.yaml \
-s dukemtmcreid \
-t dukemtmcreid \
--transforms random_flip random_erase \
--root $PATH_TO_DATA \
data.save_dir log/osnet_x1_0_dukemtmcreid_softmax_cosinelr

The code will automatically (download and) load the ImageNet pretrained weights. After the training is done, the model will be saved as "log/osnet_x1_0_market1501_softmax_cosinelr/model.pth.tar-250". Under the same folder, you can find the tensorboard file. To visualize the learning curves using tensorboard, you can run tensorboard --logdir=log/osnet_x1_0_market1501_softmax_cosinelr in the terminal and visit http://localhost:6006/ in your web browser.

Evaluation is automatically performed at the end of training. To run the test again using the trained model, do

python scripts/ \
--config-file configs/im_osnet_x1_0_softmax_256x128_amsgrad_cosine.yaml \
--root $PATH_TO_DATA \
model.load_weights log/osnet_x1_0_market1501_softmax_cosinelr/model.pth.tar-250 \
test.evaluate True

Cross-domain setting

Suppose you wanna train OSNet on DukeMTMC-reID and test its performance on Market1501, you can do

python scripts/ \
--config-file configs/im_osnet_x1_0_softmax_256x128_amsgrad.yaml \
-s dukemtmcreid \
-t market1501 \
--transforms random_flip color_jitter \
--root $PATH_TO_DATA

Here we only test the cross-domain performance. However, if you also want to test the performance on the source dataset, i.e. DukeMTMC-reID, you can set -t dukemtmcreid market1501, which will evaluate the model on the two datasets separately.

Different from the same-domain setting, here we replace random_erase with color_jitter. This can improve the generalization performance on the unseen target dataset.

Pretrained models are available in the Model Zoo.


Image-reid datasets

Video-reid datasets


ImageNet classification models

Lightweight models

ReID-specific models

Useful links


If you find this code useful to your research, please cite the following papers.

  title={Torchreid: A Library for Deep Learning Person Re-Identification in Pytorch},
  author={Zhou, Kaiyang and Xiang, Tao},
  journal={arXiv preprint arXiv:1910.10093},

  title={Omni-Scale Feature Learning for Person Re-Identification},
  author={Zhou, Kaiyang and Yang, Yongxin and Cavallaro, Andrea and Xiang, Tao},

  title={Learning Generalisable Omni-Scale Representations for Person Re-Identification},
  author={Zhou, Kaiyang and Yang, Yongxin and Cavallaro, Andrea and Xiang, Tao},
  journal={arXiv preprint arXiv:1910.06827},
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