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Spatio Temporal Action Detection Models

ACRN

Actor-centric relation network

Abstract

Current state-of-the-art approaches for spatio-temporal action localization rely on detections at the frame level and model temporal context with 3D ConvNets. Here, we go one step further and model spatio-temporal relations to capture the interactions between human actors, relevant objects and scene elements essential to differentiate similar human actions. Our approach is weakly supervised and mines the relevant elements automatically with an actor-centric relational network (ACRN). ACRN computes and accumulates pair-wise relation information from actor and global scene features, and generates relation features for action classification. It is implemented as neural networks and can be trained jointly with an existing action detection system. We show that ACRN outperforms alternative approaches which capture relation information, and that the proposed framework improves upon the state-of-the-art performance on JHMDB and AVA. A visualization of the learned relation features confirms that our approach is able to attend to the relevant relations for each action.

Results and Models

AVA2.1

Model Modality Pretrained Backbone Input gpus mAP log json ckpt
slowfast_acrn_kinetics_pretrained_r50_8x8x1_cosine_10e_ava_rgb RGB Kinetics-400 ResNet50 32x2 8 27.1 log json ckpt

AVA2.2

Model Modality Pretrained Backbone Input gpus mAP log json ckpt
slowfast_acrn_kinetics_pretrained_r50_8x8x1_cosine_10e_ava22_rgb RGB Kinetics-400 ResNet50 32x2 8 27.8 log json ckpt

Note

  1. The gpus indicates the number of gpu we used to get the checkpoint. According to the Linear Scaling Rule, you may set the learning rate proportional to the batch size if you use different GPUs or videos per GPU, e.g., lr=0.01 for 4 GPUs x 2 video/gpu and lr=0.08 for 16 GPUs x 4 video/gpu.

For more details on data preparation, you can refer to AVA in Data Preparation.

Train

You can use the following command to train a model.

python tools/train.py ${CONFIG_FILE} [optional arguments]

Example: train ACRN with SlowFast backbone on AVA with periodic validation.

python tools/train.py configs/detection/acrn/slowfast_acrn_kinetics_pretrained_r50_8x8x1_cosine_10e_ava22_rgb.py --validate

For more details and optional arguments infos, you can refer to Training setting part in getting_started.

Test

You can use the following command to test a model.

python tools/test.py ${CONFIG_FILE} ${CHECKPOINT_FILE} [optional arguments]

Example: test ACRN with SlowFast backbone on AVA and dump the result to a csv file.

python tools/test.py configs/detection/acrn/slowfast_acrn_kinetics_pretrained_r50_8x8x1_cosine_10e_ava22_rgb.py checkpoints/SOME_CHECKPOINT.pth --eval mAP --out results.csv

For more details and optional arguments infos, you can refer to Test a dataset part in getting_started .

Citation

@inproceedings{gu2018ava,
  title={Ava: A video dataset of spatio-temporally localized atomic visual actions},
  author={Gu, Chunhui and Sun, Chen and Ross, David A and Vondrick, Carl and Pantofaru, Caroline and Li, Yeqing and Vijayanarasimhan, Sudheendra and Toderici, George and Ricco, Susanna and Sukthankar, Rahul and others},
  booktitle={Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition},
  pages={6047--6056},
  year={2018}
}

@inproceedings{sun2018actor,
  title={Actor-centric relation network},
  author={Sun, Chen and Shrivastava, Abhinav and Vondrick, Carl and Murphy, Kevin and Sukthankar, Rahul and Schmid, Cordelia},
  booktitle={Proceedings of the European Conference on Computer Vision (ECCV)},
  pages={318--334},
  year={2018}
}

AVA

Ava: A video dataset of spatio-temporally localized atomic visual actions

Abstract

This paper introduces a video dataset of spatio-temporally localized Atomic Visual Actions (AVA). The AVA dataset densely annotates 80 atomic visual actions in 430 15-minute video clips, where actions are localized in space and time, resulting in 1.58M action labels with multiple labels per person occurring frequently. The key characteristics of our dataset are: (1) the definition of atomic visual actions, rather than composite actions; (2) precise spatio-temporal annotations with possibly multiple annotations for each person; (3) exhaustive annotation of these atomic actions over 15-minute video clips; (4) people temporally linked across consecutive segments; and (5) using movies to gather a varied set of action representations. This departs from existing datasets for spatio-temporal action recognition, which typically provide sparse annotations for composite actions in short video clips. We will release the dataset publicly. AVA, with its realistic scene and action complexity, exposes the intrinsic difficulty of action recognition. To benchmark this, we present a novel approach for action localization that builds upon the current state-of-the-art methods, and demonstrates better performance on JHMDB and UCF101-24 categories. While setting a new state of the art on existing datasets, the overall results on AVA are low at 15.6% mAP, underscoring the need for developing new approaches for video understanding.

@inproceedings{feichtenhofer2019slowfast,
  title={Slowfast networks for video recognition},
  author={Feichtenhofer, Christoph and Fan, Haoqi and Malik, Jitendra and He, Kaiming},
  booktitle={Proceedings of the IEEE international conference on computer vision},
  pages={6202--6211},
  year={2019}
}

Results and Models

AVA2.1

Model Modality Pretrained Backbone Input gpus Resolution mAP log json ckpt
slowonly_kinetics_pretrained_r50_4x16x1_20e_ava_rgb RGB Kinetics-400 ResNet50 4x16 8 short-side 256 20.1 log json ckpt
slowonly_omnisource_pretrained_r50_4x16x1_20e_ava_rgb RGB OmniSource ResNet50 4x16 8 short-side 256 21.8 log json ckpt
slowonly_nl_kinetics_pretrained_r50_4x16x1_10e_ava_rgb RGB Kinetics-400 ResNet50 4x16 8 short-side 256 21.75 log json ckpt
slowonly_nl_kinetics_pretrained_r50_8x8x1_10e_ava_rgb RGB Kinetics-400 ResNet50 8x8 8x2 short-side 256 23.79 log json ckpt
slowonly_kinetics_pretrained_r101_8x8x1_20e_ava_rgb RGB Kinetics-400 ResNet101 8x8 8x2 short-side 256 24.6 log json ckpt
slowonly_omnisource_pretrained_r101_8x8x1_20e_ava_rgb RGB OmniSource ResNet101 8x8 8x2 short-side 256 25.9 log json ckpt
slowfast_kinetics_pretrained_r50_4x16x1_20e_ava_rgb RGB Kinetics-400 ResNet50 32x2 8x2 short-side 256 24.4 log json ckpt
slowfast_context_kinetics_pretrained_r50_4x16x1_20e_ava_rgb RGB Kinetics-400 ResNet50 32x2 8x2 short-side 256 25.4 log json ckpt
slowfast_kinetics_pretrained_r50_8x8x1_20e_ava_rgb RGB Kinetics-400 ResNet50 32x2 8x2 short-side 256 25.5 log json ckpt

AVA2.2

Model Modality Pretrained Backbone Input gpus mAP log json ckpt
slowfast_kinetics_pretrained_r50_8x8x1_cosine_10e_ava22_rgb RGB Kinetics-400 ResNet50 32x2 8 26.1 log json ckpt
slowfast_temporal_max_kinetics_pretrained_r50_8x8x1_cosine_10e_ava22_rgb RGB Kinetics-400 ResNet50 32x2 8 26.4 log json ckpt
slowfast_temporal_max_focal_alpha3_gamma1_kinetics_pretrained_r50_8x8x1_cosine_10e_ava22_rgb RGB Kinetics-400 ResNet50 32x2 8 26.8 log json ckpt

Note

  1. The gpus indicates the number of gpu we used to get the checkpoint. According to the Linear Scaling Rule, you may set the learning rate proportional to the batch size if you use different GPUs or videos per GPU, e.g., lr=0.01 for 4 GPUs x 2 video/gpu and lr=0.08 for 16 GPUs x 4 video/gpu.

  2. Context indicates that using both RoI feature and global pooled feature for classification, which leads to around 1% mAP improvement in general.

For more details on data preparation, you can refer to AVA in Data Preparation.

Train

You can use the following command to train a model.

python tools/train.py ${CONFIG_FILE} [optional arguments]

Example: train SlowOnly model on AVA with periodic validation.

python tools/train.py configs/detection/ava/slowonly_kinetics_pretrained_r50_8x8x1_20e_ava_rgb.py --validate

For more details and optional arguments infos, you can refer to Training setting part in getting_started .

Train Custom Classes From Ava Dataset

You can train custom classes from ava. Ava suffers from class imbalance. There are more then 100,000 samples for classes like stand/listen to (a person)/talk to (e.g., self, a person, a group)/watch (a person), whereas half of all classes has less than 500 samples. In most cases, training custom classes with fewer samples only will lead to better results.

Three steps to train custom classes:

  • Step 1: Select custom classes from original classes, named custom_classes. Class 0 should not be selected since it is reserved for further usage (to identify whether a proposal is positive or negative, not implemented yet) and will be added automatically.

  • Step 2: Set num_classes. In order to be compatible with current codes, Please make sure num_classes == len(custom_classes) + 1.

    • The new class 0 corresponds to original class 0. The new class i(i > 0) corresponds to original class custom_classes[i-1].

    • There are three num_classes in ava config, model -> roi_head -> bbox_head -> num_classes, data -> train -> num_classes and data -> val -> num_classes.

    • If num_classes <= 5, input arg topk of BBoxHeadAVA should be modified. The default value of topk is (3, 5), and all elements of topk must be smaller than num_classes.

  • Step 3: Make sure all custom classes are in label_file. It is worth mentioning that there are two label files, ava_action_list_v2.1_for_activitynet_2018.pbtxt(contains 60 classes, 20 classes are missing) and ava_action_list_v2.1.pbtxt(contains all 80 classes).

Take slowonly_kinetics_pretrained_r50_4x16x1_20e_ava_rgb as an example, training custom classes with AP in range (0.1, 0.3), aka [3, 6, 10, 27, 29, 38, 41, 48, 51, 53, 54, 59, 61, 64, 70, 72]. Please note that, the previously mentioned AP is calculated by original ckpt, which is trained by all 80 classes. The results are listed as follows.

training classes mAP(custom classes) config log json ckpt
All 80 classes 0.1948 slowonly_kinetics_pretrained_r50_4x16x1_20e_ava_rgb log json ckpt
custom classes 0.3311 slowonly_kinetics_pretrained_r50_4x16x1_20e_ava_rgb_custom_classes log json ckpt
All 80 classes 0.1864 slowfast_kinetics_pretrained_r50_4x16x1_20e_ava_rgb.py log json ckpt
custom classes 0.3785 slowfast_kinetics_pretrained_r50_4x16x1_20e_ava_rgb_custom_classes log json ckpt

Test

You can use the following command to test a model.

python tools/test.py ${CONFIG_FILE} ${CHECKPOINT_FILE} [optional arguments]

Example: test SlowOnly model on AVA and dump the result to a csv file.

python tools/test.py configs/detection/ava/slowonly_kinetics_pretrained_r50_8x8x1_20e_ava_rgb.py checkpoints/SOME_CHECKPOINT.pth --eval mAP --out results.csv

For more details and optional arguments infos, you can refer to Test a dataset part in getting_started .

Citation

@inproceedings{gu2018ava,
  title={Ava: A video dataset of spatio-temporally localized atomic visual actions},
  author={Gu, Chunhui and Sun, Chen and Ross, David A and Vondrick, Carl and Pantofaru, Caroline and Li, Yeqing and Vijayanarasimhan, Sudheendra and Toderici, George and Ricco, Susanna and Sukthankar, Rahul and others},
  booktitle={Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition},
  pages={6047--6056},
  year={2018}
}

@article{duan2020omni,
  title={Omni-sourced Webly-supervised Learning for Video Recognition},
  author={Duan, Haodong and Zhao, Yue and Xiong, Yuanjun and Liu, Wentao and Lin, Dahua},
  journal={arXiv preprint arXiv:2003.13042},
  year={2020}
}

LFB

Long-term feature banks for detailed video understanding

Abstract

To understand the world, we humans constantly need to relate the present to the past, and put events in context. In this paper, we enable existing video models to do the same. We propose a long-term feature bank—supportive information extracted over the entire span of a video—to augment state-of-the-art video models that otherwise would only view short clips of 2-5 seconds. Our experiments demonstrate that augmenting 3D convolutional networks with a long-term feature bank yields state-of-the-art results on three challenging video datasets: AVA, EPIC-Kitchens, and Charades.

Results and Models

AVA2.1

Model Modality Pretrained Backbone Input gpus Resolution mAP log json ckpt
lfb_nl_kinetics_pretrained_slowonly_r50_4x16x1_20e_ava_rgb.py RGB Kinetics-400 slowonly_r50_4x16x1 4x16 8 short-side 256 24.11 log json ckpt
lfb_avg_kinetics_pretrained_slowonly_r50_4x16x1_20e_ava_rgb.py RGB Kinetics-400 slowonly_r50_4x16x1 4x16 8 short-side 256 20.17 log json ckpt
lfb_max_kinetics_pretrained_slowonly_r50_4x16x1_20e_ava_rgb.py RGB Kinetics-400 slowonly_r50_4x16x1 4x16 8 short-side 256 22.15 log json ckpt

Note

  1. The gpus indicates the number of gpu we used to get the checkpoint. According to the Linear Scaling Rule, you may set the learning rate proportional to the batch size if you use different GPUs or videos per GPU, e.g., lr=0.01 for 4 GPUs x 2 video/gpu and lr=0.08 for 16 GPUs x 4 video/gpu.

  2. We use slowonly_r50_4x16x1 instead of I3D-R50-NL in the original paper as the backbone of LFB, but we have achieved the similar improvement: (ours: 20.1 -> 24.11 vs. author: 22.1 -> 25.8).

  3. Because the long-term features are randomly sampled in testing, the test accuracy may have some differences.

  4. Before train or test lfb, you need to infer feature bank with the lfb_slowonly_r50_ava_infer.py. For more details on infer feature bank, you can refer to Train part.

  5. You can also dowonload long-term feature bank from AVA_train_val_float32_lfb or AVA_train_val_float16_lfb, and then put them on lfb_prefix_path.

  6. The ROIHead now supports single-label classification (i.e. the network outputs at most one-label per actor). This can be done by (a) setting multilabel=False during training and the test_cfg.rcnn.action_thr for testing.

Train

a. Infer long-term feature bank for training

Before train or test lfb, you need to infer long-term feature bank first.

Specifically, run the test on the training, validation, testing dataset with the config file lfb_slowonly_r50_ava_infer (The config file will only infer the feature bank of training dataset and you need set dataset_mode = 'val' to infer the feature bank of validation dataset in the config file.), and the shared head LFBInferHead will generate the feature bank.

A long-term feature bank file of AVA training and validation datasets with float32 precision occupies 3.3 GB. If store the features with float16 precision, the feature bank occupies 1.65 GB.

You can use the following command to infer feature bank of AVA training and validation dataset and the feature bank will be stored in lfb_prefix_path/lfb_train.pkl and lfb_prefix_path/lfb_val.pkl.

## set `dataset_mode = 'train'` in lfb_slowonly_r50_ava_infer.py
python tools/test.py configs/detection/lfb/lfb_slowonly_r50_ava_infer.py \
    checkpoints/YOUR_BASELINE_CHECKPOINT.pth --eval mAP

## set `dataset_mode = 'val'` in lfb_slowonly_r50_ava_infer.py
python tools/test.py configs/detection/lfb/lfb_slowonly_r50_ava_infer.py \
    checkpoints/YOUR_BASELINE_CHECKPOINT.pth --eval mAP

We use slowonly_r50_4x16x1 checkpoint from slowonly_kinetics_pretrained_r50_4x16x1_20e_ava_rgb to infer feature bank.

b. Train LFB

You can use the following command to train a model.

python tools/train.py ${CONFIG_FILE} [optional arguments]

Example: train LFB model on AVA with half-precision long-term feature bank.

python tools/train.py configs/detection/lfb/lfb_nl_kinetics_pretrained_slowonly_r50_4x16x1_20e_ava_rgb.py \
  --validate --seed 0 --deterministic

For more details and optional arguments infos, you can refer to Training setting part in getting_started.

Test

a. Infer long-term feature bank for testing

Before train or test lfb, you also need to infer long-term feature bank first. If you have generated the feature bank file, you can skip it.

The step is the same with Infer long-term feature bank for training part in Train.

b. Test LFB

You can use the following command to test a model.

python tools/test.py ${CONFIG_FILE} ${CHECKPOINT_FILE} [optional arguments]

Example: test LFB model on AVA with half-precision long-term feature bank and dump the result to a csv file.

python tools/test.py configs/detection/lfb/lfb_nl_kinetics_pretrained_slowonly_r50_4x16x1_20e_ava_rgb.py \
    checkpoints/SOME_CHECKPOINT.pth --eval mAP --out results.csv

For more details, you can refer to Test a dataset part in getting_started.

Citation

@inproceedings{gu2018ava,
  title={Ava: A video dataset of spatio-temporally localized atomic visual actions},
  author={Gu, Chunhui and Sun, Chen and Ross, David A and Vondrick, Carl and Pantofaru, Caroline and Li, Yeqing and Vijayanarasimhan, Sudheendra and Toderici, George and Ricco, Susanna and Sukthankar, Rahul and others},
  booktitle={Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition},
  pages={6047--6056},
  year={2018}
}

@inproceedings{wu2019long,
  title={Long-term feature banks for detailed video understanding},
  author={Wu, Chao-Yuan and Feichtenhofer, Christoph and Fan, Haoqi and He, Kaiming and Krahenbuhl, Philipp and Girshick, Ross},
  booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
  pages={284--293},
  year={2019}
}
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