Segment-CNN

By Zheng Shou, Dongang Wang, and Shih-Fu Chang.

Introduction

Segment-CNN (S-CNN) is a segment-based deep learning framework for temporal action localization in untrimmed long videos.

This code has been tested on Ubuntu 14.04 with NVIDIA GTX 980.

Current code is our rough version and we are improving its implementation details, while the current version suffices to run demo, repeat our experimental results, and train your own models. Please use "GitHub Issues" to ask questions or report bugs. Thanks.

License

S-CNN is released under the MIT License (refer to the LICENSE file for details).

Citing

If you find S-CNN useful, please consider citing:

@inproceedings{scnn_shou_wang_chang_cvpr16,
  author = {Zheng Shou and Dongang Wang and Shih-Fu Chang},
  title = {Temporal Action Localization in Untrimmed Videos via Multi-stage CNNs},
  year = {2016},
  booktitle = {CVPR} 
  }

We build this repo based on C3D and THUMOS Challenge 2014 . Please cite the following papers as well:

D. Tran, L. Bourdev, R. Fergus, L. Torresani, and M. Paluri, Learning Spatiotemporal Features with 3D Convolutional Networks, ICCV 2015.

Y. Jia, E. Shelhamer, J. Donahue, S. Karayev, J. Long, R. Girshick, S. Guadarrama, and T. Darrell, Caffe: Convolutional Architecture for Fast Feature Embedding, arXiv 2014.

A. Karpathy, G. Toderici, S. Shetty, T. Leung, R. Sukthankar, and L. Fei-Fei, Large-scale Video Classification with Convolutional Neural Networks, CVPR 2014.

@misc{THUMOS14,
  author = "Jiang, Y.-G. and Liu, J. and Roshan Zamir, A. and Toderici, G. and Laptev, I. and Shah, M. and Sukthankar, R.",
  title = "{THUMOS} Challenge: Action Recognition with a Large Number of Classes",
  howpublished = "\url{http://crcv.ucf.edu/THUMOS14/}",
  Year = {2014}
  }

Installation:

0. Download ffmpeg from https://www.ffmpeg.org/ to ./lib/preprocess/
1. Compile 3D CNN:
   • Compile C3D_sample_rate, which is used for the proposal network and classification network
   • Compile C3D_overlap_loss, which is used for the localization network
   • Hint: please refer to C3D and Caffe for more details about compilation
2. Download pre-trained models to ./models/: either from Dropbox or Baiduyun

Run demo:

0. change to demo directory: cd ./demo/.
1. run the demo using the matlab code run_demo.m or the python code run_demo.py.
2. find the final result in the folder ./pred/final/. either in .mat format (for matlab) or .csv format (for python).
   • Note for the meaning of in seg_swin. Each row stands for one candidate segment. As for each column:
     • 1: video name in THUMOS14 test set
     • 2: sliding window length measured by number of frames
     • 3: start frame index
     • 4: end frame index
     • 5: start time
     • 6: end time
     • 9: confidence score of being the class indicated in the column 11
     • 10: confidence score of being action/non-background
     • 11: the predicted action class (from the 20 action classes and the background)
     • 12: sliding window overlap. all 0.25. means using 75% overlap window.
   • Note for the meaning of res:
     • this matrix represents the confidence score on each frame per each class
     • column corresponds to each frame and row corresponds to each action class
     • the size of this matrix: the number of action classes (20 here) by the number of frames

Our pre-trained models and pre-computed results of S-CNN on THUMOS Challenge 2014 action detection task:

0. Models:
   • ./models/conv3d_deepnetA_sport1m_iter_1900000: C3D model pre-trained on Sports1M dataset by Tran et al;
   • ./models/THUMOS14/proposal/snapshot/SCNN_uniform16_binary_iter_30000: our trained S-CNN proposal network;
   • ./models/THUMOS14/classification/snapshot/SCNN_uniform16_cls20_iter_30000: our trained S-CNN classification network;
   • ./models/THUMOS14/localization/snapshot/SCNN_uniform16_cls20_with_overlap_loss_iter_30000: our trained S-CNN localization network.
1. Results:
   • ./experiments/THUMOS14/network_proposal/result/res_seg_swin.mat: contains the output results of the proposal network. we keep segment whose confidence score of being action >= 0.7 as the candidate segment to further input into the following localization network;
   • ./experiments/THUMOS14/network_localization/result/res_seg_swin.mat: contains the output results of the localization network;
   • evaluate mAP: run ./experiments/THUMOS14/eval/eval_scnn_thumos14.m and results are stored in ./experiments/THUMOS14/eval/res_scnn_thumos14.mat. we vary the overlap threshold IoU used in evaluation from 0.1 to 0.5

Train your own model:

0. We provide the parameter settings and the network architecture definition inside ./experiments/THUMOS14/network_proposal/, ./experiments/THUMOS14/network_classification/, ./experiments/THUMOS14/network_localization/ respectively.
1. We also provide sample input data file to illustrate input data file list format, which is slightly different from C3D:
   • still, each row corresponds to one input segment
   • C3D_sample_rate (used for proposal and classification network):
     • format: video_frame_directory start_frame_index class_label stepsize
     • stepsize: used for adjusting the window length. measure the step between two consecutive frames in one segment. the frame index of the current frame + stepsize = the frame index of the subsequent frame. note that each segment consists of 16 frames in total.
     • example: /dataset/THUMOS14/val/validation_frm_all/video_validation_0000051/ 2561 3 8
   • C3D_overlap_loss (used for localization network):
     • format: video_frame_directory start_frame_index class_label stepsize overlap
     • overlap: the overlap measured by IoU between the candidate segment and the corresponding ground truth segment
     • example: /dataset/THUMOS14/val/validation_frm_all/video_validation_0000051/ 2561 3 8 0.70701
2. NOTE: please refer to C3D and Caffe for more general instructions about how to train 3D CNN model.