Crowd counting has attracted increasing attentions in recent years due to its challenges and wide societal applications. Despite persevering efforts made by the research community, most of existing methods require a large amount of location-level annotations. Collecting such type of fine-granularity supervisory signals is extremely time-consuming and labour-intensive, thereby hindering the well generalization of these location-adherent models. To shun this drawback, several pioneering studies open a promising research direction of location-agonistic crowd counting. Albeit the noticeable efforts, they somewhat ignore the merits of diverse learning paradigms and the issue of intractable density shift. To ameliorate these issues, in this paper, a novel Dynamic Mixture of Counter Network (DMCNet) is proposed for location-agnostic crowd counting. Specifically, our DMCNet inherits the hybrid advantages of CNNs (e.g. locality-oriented and pyramidal property) and MLP-based structure (e.g. global receptive fields and light weight). Particularly, the dynamic counter predictor and the mixture of counter heads are delicately designed to hammer at combating huge density shift and overfitting. Extensive experiments demonstrate that our DMCNet attains state-of-the-art performance against existing location-agnostic approaches and performs on par with many conventional location-adherent ones.

State-of-the-art approaches for crowd counting resort to deepneural networks to predict density maps. However, counting people in congested scenes remains a challenging task because the presence of drastic scale variation, density inconsistency, and complex background can seriously degrade their counting accuracy. To battle the ingrained issue of accuracy degradation, in this paper, we propose a novel and powerful network called Scale Tree Network (STNet) for accurate crowd counting. STNet consists of two key components: a Scale-Tree Diversity Enhancer and a Multi-level Auxiliator. Specifically, the Diversity Enhancer is designed to enrich scale diversity, which alleviates limitations of existing methods caused by insufficient level of scales. A novel tree structure is adopted to hierarchically parse coarse-to-fine crowd regions. Furthermore, a simple yet effective Multi-level Auxiliator is presented to aid in exploiting generalisable shared characteristics at multiple levels, allowing more accurate pixel-wise background cognition. The overall STNet is trained in an end-to-end manner, without the needs for manually tuning loss weights between the main and the auxiliary tasks. Extensive experiments on five challenging crowd datasets demonstrate the superiority of the proposed method.

Crowd counting from unconstrained and congested scenes is an important task in computer vision. Its main difficulties stem from large scale/density variation and prone to over-fitting. This paper presents a novel end-to-end stochastic multi-scale aggregation network (SMANet) which carefully addresses these issues. Specifically, general features are first extracted by the front-end subnetwork and then fed into the back-end subnetwork which consists of stochastic multi-scale aggregation module, density map generator, and global prior encoder. The stochastic aggregation impels the multi-branch units to learn features at different scales effectively and reduces sensitivity to scale variations, whereas the global prior encoder is designed to encode global contextual information and guarantee density consistency of shared representations. Our proposed SMANet is the first work to fuse multi-scale features in a stochastic manner for crowd counting. Experimental results on four public datasets demonstrate that our SMANet consistently outperforms the state-of-the-arts.

Convolutional neural networks (CNNs) have demonstrated great success in vision tasks. However, most existing architectures still suffer from low feature reuse efficiency. In this paper, we present a layer attention based Adaptively Dense Network (ADNet) by adaptively determining the reuse status of hierarchical preceding features. Specifically, a dense residual aggregation strategy is developed to fuse multi-level internal representations in an effective manner. Furthermore, a novel layer attention mechanism is proposed to explicitly model the interrelationship among layers to automatically adjust the density of the network. It is worth noting that existing ResNets and DenseNets are both special cases of our ADNet. Extensive experiments demonstrate that the proposed architecture consistently and indubitably achieves competitive results in accuracy on benchmark datasets (CIFAR10, CIFAR100, and SVHN), while at the same time remarkably reduces computational costs and memory space. Visualization and analysis on layer-wise attention further provide better understanding on the density of feature reuse in Deep Networks.

We introduce BSD-GAN, a novel multi-branch and scale-disentangled training method which enables unconditional Generative Adversarial Networks (GANs) to learn image representations at multiple scales, benefiting a wide range of generation and editing tasks. The key feature of BSD-GAN is that it is trained in multiple branches, progressively covering both the breadth and depth of the network, as resolutions of the training images increase to reveal finer-scale features. Specifically, each noise vector, as input to the generator network of BSD-GAN, is deliberately split into several sub-vectors, each corresponding to, and is trained to learn, image representations at a particular scale. During training, we progressively "de-freeze" the sub-vectors, one at a time, as a new set of higher-resolution images is employed for training and more network layers are added. A consequence of such an explicit sub-vector designation is that we can directly manipulate and even combine latent (sub-vector) codes which model different feature scales. Extensive experiments demonstrate the effectiveness of our training method in scale-disentangled learning of image representations and synthesis of novel image contents, without any extra labels and without compromising quality of the synthesized high-resolution images. We further demonstrate several image generation and manipulation applications enabled or improved by BSD-GAN.

Distortions cause structural changes in digital images, leading to degraded visual quality. Dictionary-based sparse representation has been widely studied recently due to its ability to extract inherent image structures. Meantime, it can extract image features with slightly higher level semantics. Intuitively, sparse representation can be used for image quality assessment, because visible distortions can cause significant changes to the sparse features. In this paper, a new sparse representation-based image quality assessment model is proposed based on the construction of adaptive sub-dictionaries. An overcomplete dictionary trained from natural images is employed to capture the structure changes between the reference and distorted images by sparse feature extraction via adaptive sub-dictionary selection. Based on the observation that image sparse features are invariant to weak degradations and the perceived image quality is generally influenced by diverse issues, three auxiliary quality features are added, including gradient, color, and luminance information. The proposed method is not sensitive to training images, so a universal dictionary can be adopted for quality evaluation. Extensive experiments on five public image quality databases demonstrate that the proposed method produces the state-of-the-art results, and it delivers consistently well performances when tested in different image quality databases.