Multi-Camera Person Re-Identification

This repository is inspired by the paper Spatial-Temporal Reidentification (ST-ReID)[1]. The state-of-the-art for Person Re-identification tasks. This repository offers a flexible, and easy to understand clean implementation of the model architecture, training and evaluation.

This repository has been trained & tested on DukeMTMTC-reID and Market-1501 datasets. The model can be easily trained on any new datasets with a few tweaks to parse the files!

You can do a quick run on Google Colab:

Below are the metrics on the various datasets.

Model	Size	Dataset	mAP	CMC: Top1	CMC: Top5
resnet50-PCB+rerank		Market	95.5	98.0	98.9
resnet50-PCB+rerank		Duke	92.7	94.5	96.8

Model Architecture

Source: Spatial-Temporal Reidentification(ST-ReID)

1. A pre-trained ResNet-50 backbone model with layers up until Adaptive Average Pooling(excluded) is used

During Training

1. The last Convolutional layer is broken into 6 (Final output size: 6 x 1) parts and separately used for predicting the person label.
2. The total loss of the 6 part predictions are calculated for backpropagation & weights update.

During Testing/Evaluation/Deployment

1. Only the visual feature stream up until Adaptive Average Pooling is used.
2. The feature vector of the query image is compared against all the feature vectors of the gallery images using a simple dot product & normalization.
3. The Spatio-Temporal distribution is used to calculate their spatio-temporal scores.
4. The joint score is then calculated from the feature score and the spatio-temporal scores.
5. The Cumulated Matching Score is used to find the best matching for person from the gallet set.

Getting Started

Run the below commands in the shell.

1. Clone this repo, cd into it & install setup.py:

git clone https://github.com/SurajDonthi/MTMCT-Person-Re-Identification

cd MTMCT-Person-Re-Identification

pip install -r requirements.txt

2. Download the datasets. (By default you can download & unzip them to data/raw/ directory)

You can get started by training this model. Trained models will be available soon!

Dependencies

This project requires pytorch>=1.5.0, torchvision>=0.6.0, pytorch-lightning=1.1.1, tensorboard, joblib and other common packages like numpy, matplotlib and csv.

NOTE: This project uses pytorch-lightning which is a high-level interface to abstract away repeating Pytorch code. It helps achieve clean, & easy to maintain code with hardly any learning curve!

Train with your own dataset

Run the below command in the shell.

python -m mtmct_reid.train --data_dir path/to/dataset/ --dataset 'market' \
    --save_distribution path/to/dataset/st_distribution.pkl --gpus 1 --max_epochs 60

For a detailed list of arguments you can pass, refer to hparams.csv

Monitor the training on Tensorboard

Log files are created to track the training in a new folder logs. To monitor the training, run the below command in the shell

tensorboard --logdir logs/

Prediction/Evaluation

Using commandline:

python -m mtmct_reid.eval model_path 'path/to/model' --dataset 'market' \
    --query_data_dir 'path/to/query_data/' --gallery_data_dir 'path/to/gallery_data' \
    --st_distribution_path 'path/to/spatio-temporal_distribution' \
    --batch_size 64 --num_workers 4 --re_rank True

Metrics

The evaluation metrics used are mAP (mean Average Precision) & CMC (Cumulated Matching Characteristics)

Finding the best matches during testing:

Step 1: From a given dataset, compute it's Spatial-Temporal Distribution.

Requires: cam_ids, targets(labels), frames, MODEL is not required!

Step 2: Compute it's Gaussian smoothed ST-Distribution.

Requires: cam_ids, targets(labels), frames, MODEL is not required!

Step 3: Compute the L2-Normed features that is generated from the model.

Requires: Features - Performed once training is finished!

Step 4: Compute the Joint Scores.

Requires: Smoothed Distribution & L2-Normed Features, cam_ids, frames

Step 5: Optionally perform Re-ranking of the Generated scores.

Requires: Joint Scores

Step 6: Compute mAP & CMC (Cumulated Matching Characteristics; for Rank-1,Rank-5, Rank-10) for each query.

Requires: Reranked/Joint Scores, (query labels & cams), (gallery labels & cams)

References:

[1] - Spatial-Temporal Reidentification(ST-ReID)

[2] - Beyond Parts Models: Person Retrieval with Refined Part Pooling

Related repos:

The model logic is mainly based on this repository.