Discovering Dynamic Salient Regions with Spatio-Temporal Graph Neural Networks

This is the official code for DyReg model inroduced in Discovering Dynamic Salient Regions with Spatio-Temporal Graph Neural Networks

Citation

Please use the following BibTeX to cite our work.

@incollection{duta2021dynamic_dyreg_gnn_neurips2021,
title = {Discovering Dynamic Salient Regions with Spatio-Temporal Graph
Neural Networks},
author = {Duta, Iulia and Nicolicioiu, Andrei and Leordeanu, Marius},
booktitle = {Advances in Neural Information Processing Systems 34},
year = {2021}
}

@article{duta2020dynamic_dyreg,
title = {Dynamic Regions Graph Neural Networks for Spatio-Temporal Reasoning},
author = {Duta, Iulia and Nicolicioiu, Andrei and Leordeanu, Marius},
journal = {NeurIPS 2020 Workshop on Object Representations for Learning and Reasoning},
year = {2020},
}

Requirements

The code was developed using:

- python 3.7
- matplotlib
- torch 1.7.1
- script
- pandas
- torchvision
- moviepy
- ffmpeg

Overview:

The repository contains the Pytorch implementation of the DyReg-GNN model. The model is defined and trained in the following files:

• ops/dyreg.py - code for our DyReg module

• ops/rstg.py - code for the Spatio-temporal GNN (RSTG) used to process the graph extracted using DyReg

• create_model.py - two examples how to integrate the DyReg-GNN module inside an existing backbone

• main_standard.py - code to train a model on Smt-Smt dataset

• test_models.py - code for multi-clip evaluation

Scripts for preparing the data, training and testing the model:

• train_model.sh - example of script to train DyReg-GNN

• evaluate_model.sh - example of script to evaluate on a single clip DyReg-GNN

• evaluate_model_multi_clip.sh - example of script to evaluate on multiple clips DyReg-GNN

• tools/ contains all the script used to prepare Smt-Smt dataset (similar to the setup used in TSM)

Prepare dataset

For Something Something dataset:

• the json files containing meta-data should be stored in ./data/smt-smt-V2/tsm_data
• the zip files containing the videos should be stored in ./data/smt-smt-V2/

---

1. To extract the videos from the zip files run:

cat 20bn-something-something-v2-?? | tar zx

2. To extract the frames from videos run:

python tools/vid2img_sthv2.py

→ The videos will be stored in $FRAME_ROOT (default './data/smt-smt-V2/tmp_smt-smt-V2-frames')

💡 If you already have the dataset as frames, place them under ./data/smt-smt-V2/smt-smt-V2-frames/, one folder for each video
💡💡 If you need to change the path for datasets modify $ROOT_DATASET in dataset_config.py

3. To generate the labels file in the required format please run:

python tools/gen_label_sthv2.py

→ The resulting txt files, for each split, will be stored in $DATA_UTILS_ROOT (default './data/smt-smt-V2/tsm_data/')

How to run the model

DyReg-GNN module can be simply inserted into any space-time model.

import torch
from torch.nn import functional as F
from ops.dyreg import DynamicGraph, dyregParams

class SpaceTimeModel(torch.nn.Module):
    def __init__(self):
        super(SpaceTimeModel, self).__init__()
        dyreg_params = dyregParams()
        dyregParams.offset_lstm_dim = 32
        self.dyreg = DynamicGraph(dyreg_params,
                    backbone_dim=32, node_dim=32, out_num_ch=32,
                    H=16, W=16, 
                    iH=16, iW=16,
                    project_i3d=False,
                    name='lalalal')


        self.fc = torch.nn.Linear(32, 10)

    def forward(self, x):
        dx = self.dyreg(x)
        # you can initialize the dyreg branch as identity function by normalisation, 
        #   as done in DynamicGraphWrapper found in ./ops/dyreg.py 
        x = x + dx
        # average over time and space: T, H, W
        x = x.mean(-1).mean(-1).mean(-2)
        x = self.fc(x)
        return x


B = 8
T = 10
C = 32
H = 16
W = 16
x = torch.ones(B,T,C,H,W)
st_model = SpaceTimeModel()
out = st_model(x)

For another example of how to integrate DyReg (DynamicGraph module) inside your model please look at create_model.py or run:

python create_model.py

Something-Something experiments

Training a model

To train a model on smt-smt v2 dataset please run

./start_main_standard.sh model_name

For default hyperparameters check opts.py. For example, place_graph flag controls how many DyReg-GNN modules to use and where to place them inside the backbone:

# for a model with 3 DyReg-GNN modules placed after layer 2-block 2, layer 3-block 4 and layer 4-block 1 of the backbone
--place_graph=layer2.2_layer3.4_layer4.1 
# for a model with 1 dyreg module placed after layer 3 block 4 of the backbone
--place_graph=layer3.4                   

Single clip evaluation

Train a model with the above script or download a pre-trained DyReg-GNN model from here and put the checkpoint in ./ckeckpoints/

To evaluate a model on smt-smt v2 dataset on a single 224 x 224 central crop, run:

./start_main_standard_test.sh model_name

The flag $RESUME_CKPT indicate the the checkpoint used for evaluation.

Multi clips evaluation

To evaluate a model in the multi-clips setup (3 spatials clips x 2 temporal samplings) on Smt-Smt v2 dataset please run

./evaluate_model.sh model_name

The flag $RESUME_CKPT indicate the the checkpoint used for evaluation.

TSM Baseline

This repository adds DyReg-GNN modules to a TSM backbone based on code from here.