Infrared dim-small target detection, as an important branch of object detection, has been attracting research attention in recent decades. Its challenges mainly lie in the small target sizes and dim contrast to background images. Recent research schemes on it mainly focus on improving the feature representation of spatio-temporal domains only in single-slice temporal scope. More cross-slice motion, i.e., past and future, is seldom considered to enhance target features. To use cross-slice motion context, this article proposes a sliced spatio-temporal network (SSTNet) with cross-slice enhancement for moving infrared dim-small target detection. In our scheme, a new cross-slice ConvLSTM node is designed to capture spatio-temporal motion features from both inner slice and inter-slices. Moreover, to improve infrared small target motion feature learning, we extend conventional loss function by adopting a new motion-coordination loss (MCL) term. On these, we propose a motion-coupling neck to assist feature extractor in facilitating the capturing and utilization of motion features from multiframes. To our best knowledge, our work is the first one to explore the cross-slice spatio-temporal motion modeling for infrared dim-small targets. Experiments verify that our SSTNet could refresh most state-of-the-art metrics on two public benchmarks (DAUB and IRDST). Our source codes are available at https://github.com/UESTC-nnLab/SSTNet .

As a sub-field of object detection, moving infrared small target detection presents significant challenges due to tiny target sizes and low contrast against backgrounds. Currently-existing methods primarily rely on the features extracted only from spatio-temporal domain. Frequency domain has hardly been concerned yet, although it has been widely applied in image processing. To extend feature source domains and enhance feature representation, we propose a new Triple-domain Strategy (Tridos) with the frequency-aware memory enhancement on spatio-temporal domain for infrared small target detection. In this scheme, it effectively detaches and enhances frequency features by a local-global frequency-aware module with Fourier transform. Inspired by human visual system, our memory enhancement is designed to capture the spatial relations of infrared targets among video frames. Furthermore, it encodes temporal dynamics motion features via differential learning and residual enhancing. Additionally, we further design a residual compensation to reconcile possible cross-domain feature mismatches. To our best knowledge, proposed Tridos is the first work to explore infrared target feature learning comprehensively in spatio-temporal-frequency domains. The extensive experiments on three datasets (i.e., DAUB, ITSDT-15K and IRDST) validate that our triple-domain infrared feature learning scheme could often be obviously superior to state-of-the-art ones. Source codes are available at https://github.com/UESTC-nnLab/Tridos.

Given the special situation of modeling gigapixel images, multiple instance learning (MIL) has become one of the most important frameworks for Whole Slide Image (WSI) classification. In current practice, most MIL networks often face two unavoidable problems in training: i) insufficient WSI data and ii) the sample memorization inclination inherent in neural networks. These problems may hinder MIL models from adequate and efficient training, suppressing the continuous performance promotion of classification models on WSIs. Inspired by the basic idea of Mixup, this paper proposes a new Pseudo-bag Mixup (PseMix) data augmentation scheme to improve the training of MIL models. This scheme generalizes the Mixup strategy for general images to special WSIs via pseudo-bags so as to be applied in MIL-based WSI classification. Cooperated by pseudo-bags, our PseMix fulfills the critical size alignment and semantic alignment in Mixup strategy. Moreover, it is designed as an efficient and decoupled method, neither involving time-consuming operations nor relying on MIL model predictions. Comparative experiments and ablation studies are specially designed to evaluate the effectiveness and advantages of our PseMix. Experimental results show that PseMix could often assist state-of-the-art MIL networks to refresh their classification performance on WSIs. Besides, it could also boost the generalization performance of MIL models in special test scenarios, and promote their robustness to patch occlusion and label noise. Our source code is available at https://github.com/liupei101/PseMix.