Paper ibrahim et al, cvpr 2016 - A Hierarchical Deep Temporal Model for Group Activity Recognition -
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A Hierarchical Deep Temporal Model for Group Activity Recognition. Mostafa S. Ibrahim, Srikanth Muralidharan, Zhiwei Deng, Arash Vahdat, Greg Mori. IEEE Computer Vision and Pattern Recognition 2016

Contents

  1. History
  2. Abstract
  3. Model
  4. Dataset
  5. Experiments
  6. Installation
  7. License and Citation
  8. Poster and Powerpoint

History

  • The first version of this work is accepted at CVPR 2016.
  • An extended work is uploaded on arxiv. Link.
  • This version builds on the previous version to include the following:
    • We have collected an expanded Volleyball dataset that is 3 times larger than CVPR submission.
    • We conducted further analysis of experimental results and included comparisons to an additional set of baseline methods.
    • We implemented a variant of our approach to perform spatial pooling strategies over people.
  • The provided dataset is the expanded version. Please use and compare against this version.

Abstract

In group activity recognition, the temporal dynamics of the whole activity can be inferred based on the dynamics of the individual people representing the activity. We build a deep model to capture these dynamics based on LSTM models. To make use of these observations, we present a 2-stage deep temporal model for the group activity recognition problem. In our model, a LSTM model is designed to represent action dynamics of individual people in a sequence and another LSTM model is designed to aggregate person-level information for whole activity understanding. We evaluate our model over two datasets: the Collective Activity Dataset and a new volleyball dataset.

Model

Figure 1

Figure 1: High level figure for group activity recognition via a hierarchical model. Each person in a scene is modeled using a temporal model that captures his/her dynamics, these models are integrated into a higher-level model that captures scene-level activity.

Figure 2

Figure 2: Detailed figure for the model. Given tracklets of K-players, we feed each tracklet in a CNN, followed by a person LSTM layer to represent each player's action. We then pool over all people's temporal features in the scene. The output of the pooling layer is feed to the second LSTM network to identify the whole teams activity.

Figure 3

Figure 3: Previous basic mode drops spatial information. In updated model, 2-group pooling to capture spatial arrangements of players.

Dataset

Download Link

UPDATE 1: many people asked for extracted trajectories. In fact, as in our code, we generate them on the fly using Dlib Tracker. I extrated and saved them to disk (I did few verifications). Hopefully this helps more. Download.

UPDATE 2: My College, Jiawei (Eric) He, Recently trained 2 Faster-RCNN detectors using the training detections. One detector just detects the person. The other one detects the action of the person. Each row has format: [Image name # of detections x y w h confidence category (for each detection)]. Multiple scenarios such data can be useful and cut your time. I did few verifications over them. Notice, these data are not used in our models. They are provided to help :). Download.

We collected a new dataset using publicly available YouTube volleyball videos. We annotated 4830 frames that were handpicked from 55 videos with 9 player action labels and 8 team activity labels.

Figure 3

Figure 3: A frame labeled as Left Spike and bounding boxes around each team players is annotated in the dataset.

Figure 4

Figure 4: For each visible player, an action label is annotaed.

We used 3493 frames for training, and the remaining 1337 frames for testing. The train-test split of is performed at video level, rather than at frame level so that it makes the evaluation of models more convincing. The list of action and activity labels and related statistics are tabulated in following tables:

Group Activity Class No. of Instances
Right set 644
Right spike 623
Right pass 801
Right winpoint 295
Left winpoint 367
Left pass 826
Left spike 642
Left set 633
Action Classes No. of Instances
Waiting 3601
Setting 1332
Digging 2333
Falling 1241
Spiking 1216
Blocking 2458
Jumping 341
Moving 5121
Standing 38696

Further information:

  • The dataset contains 55 videos. Each video has a folder for it with unique IDs (0, 1...54)
  • Train Videos: 1 3 6 7 10 13 15 16 18 22 23 31 32 36 38 39 40 41 42 48 50 52 53 54
  • Validation Videos: 0 2 8 12 17 19 24 26 27 28 30 33 46 49 51
  • Test Videos: 4 5 9 11 14 20 21 25 29 34 35 37 43 44 45 47
  • Inside each video directory, a set of directories corresponds to annotated frames (e.g. volleyball/39/29885)
    • Video 39, frame ID 29885
  • Each frame directory has 41 images (20 images before target frame, target frame, 20 frames after target frame)
    • E.g. for frame ID: 29885 => Window = {29865, 29866.....29885, 29886....29905}
    • Scences change quite rapidly in volleyball, hence frames beyond that window shouldn't represent belong to target frame most of time.
    • In our work, we used 5 before and 4 after frames.
  • Each video directory has annotations.txt file that contains selected frames annotations.
  • Each annotation line in format: {Frame ID} {Frame Activity Class} {Player Annotation} {Player Annotation} ...
    • Player Annotation corresponds to a tight bounding box surrounds each player
  • Each {Player Annotation} in format: {Action Class} X Y W H
  • Videos with resolution of 1920x1080 are: 2 37 38 39 40 41 44 45 (8 in total). All others are 1280x720.

Experiments

Figure 5

Table 1: Comparison of the team activity recognition performance of baselines against our model evaluated on the Volleyball Dataset. Experiments are using 2 group styles with max pool strategy. Last 3 entries comparison against Improved Dense Trajectories approach.

Installation

  • There are 2 internal projects: a simple one for sake of validation and other one, the real pipeline.
  • Download and Install Dlib library.
  • Download and Install Caffe-LSTM library.
    • Assume your download disk path is $lstm_path
  • cd $lstm_path/examples
  • git clone https://github.com/mostafa-saad/deep-activity-rec.git
  • Open makefile at examples/deep-activity-rec
    • Update path locations of variables CAFFE_LSTM_DIR and DLIB_DIR
    • Update the INCS_DIRS and LIBS_DIRS (based on your environment)
  • Open examples/deep-activity-rec/ibrahim16-cvpr-simple/script-simple.sh
    • Update path variable for CAFFE
  • cd examples/deep-activity-rec
  • Compile code: make all
  • cd ../..
  • Run: examples/deep-activity-rec/ibrahim16-cvpr-simple/script-simple.sh
  • Make sure top console lines don't complain about "NOT exist directory".
  • You may validate overall console processing with file script-simple-expected-log.txt
  • If so, fix it, use script-clean.sh, run script-simple.sh.
  • The code process is of multiple stages as outlined in the script file.
    • Processing should end with simple accuracy table, all of it being close to zeros.
    • The key is to check the console log and to make sure there are no errors found.
    • Otherwise, read the script and try to get the different phases and read logs to get the errors.
    • Every sub-directory under ibrahim16-cvpr-simple has 1 or more logs.
    • Directory p4-network2 should have the final model and accuracy table.
  • If everything went alright, we can proceed with actual pipeline.
  • Download the dataset to path deep-activity-rec/volleyball
  • Same directory structure as given deep-activity-rec/volleyball-simple
  • Whatever steps/changes you did for ibrahim16-cvpr-simple, do it for ibrahim16-cvpr.
  • Run: examples/deep-activity-rec/ibrahim16-cvpr/script.sh
  • GPU/CPU note:
    • The script.sh has 2 heavy processing phases that needs CPU.
    • One can also run the following 2 scripts in parallel on CPU: script-p1-data.sh and script-p2-data-fuse.sh
    • Then Run on GPU following script: script-p1-train-p3-p4.sh
    • The main script runs all these scripts in the required order.

License and Citation

Source code is released under the BSD 2-Clause license

In case using our extended dataset, please site the following 2 publications. Otherwise, cite a suitable subset of them:

@inproceedings{msibrahiCVPR16deepactivity,
  author    = {Mostafa S. Ibrahim and Srikanth Muralidharan and Zhiwei Deng and Arash Vahdat and Greg Mori},
  title     = {A Hierarchical Deep Temporal Model for Group Activity Recognition.},
  booktitle = {2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
  year      = {2016}
}

@inproceedings{msibrahiPAMI16deepactivity,
  author    = {Mostafa S. Ibrahim and Srikanth Muralidharan and Zhiwei Deng and Arash Vahdat and Greg Mori},
  title     = {Hierarchical Deep Temporal Models for Group Activity Recognition.},
  journal   = {arXiv preprint arXiv:1607.02643},
  year      = {2016}
}

Poster and Powerpoint

  • You can find a presentation for the paper here.
  • You can find our CVPR 2016 poster here.

Poster

Mostafa on left and Srikanth on right while presenting the poster.