In this paper, we propose a novel SpatioTemporal convolutional Dense Network (STDNet) to address the video-based crowd counting problem, which contains the decomposition of 3D convolution and the 3D spatiotemporal dilated dense convolution to alleviate the rapid growth of the model size caused by the Conv3D layer. Moreover, since the dilated convolution extracts the multiscale features, we combine the dilated convolution with the channel attention block to enhance the feature representations. Due to the error that occurs from the difficulty of labeling crowds, especially for videos, imprecise or standard-inconsistent labels may lead to poor convergence for the model. To address this issue, we further propose a new patch-wise regression loss (PRL) to improve the original pixel-wise loss. Experimental results on three video-based benchmarks, i.e., the UCSD, Mall and WorldExpo’10 datasets, show that STDNet outperforms both image- and video-based state-of-the-art methods. The source codes are released athttps://github.com/STDNet/STDNet.

To exploit rich information from unlabeled data, in this work, we propose a novel self-supervised framework for visual tracking which can easily adapt the state-of-the-art supervised Siamese-based trackers into unsupervised ones by utilizing the fact that an image and any cropped region of it can form a natural pair for self-training. Besides common geometric transformation-based data augmentation and hard negative mining, we also propose adversarial masking which helps the tracker to learn other context information by adaptively blacking out salient regions of the target. The proposed approach can be trained offline using images only without any requirement of manual annotations and temporal information from multiple consecutive frames. Thus, it can be used with any kind of unlabeled data, including images and video frames. For evaluation, we take SiamFC as the base tracker and name the proposed self-supervised method as S2SiamFC. Extensive experiments and ablation studies on the challenging VOT2016 and VOT2018 datasets are provided to demonstrate the effectiveness of the proposed method which not only achieves comparable performance to its supervised counterpart and other unsupervised methods requiring multiple frames.