In the field of class incremental leaming (CIL), generative replay has become increasingly prominent as a method to mitigate the catastrophic forgetting, alongside the continuous improvements in generative models. However, its application in class incremental object detection (CIOD) has been significantly limited, primarily due to the complexities of scenes involving multiple labels. In this paper, we propose a novel approach called stable diffusion deep generative replay (SDDGR) for CIOD. Our method utilizes a diffusion-based generative model with pre-trained text-to-image diffusion networks to generate realistic and diverse synthetic images. SDDGR incorporates an iterative refinement strategy to produce high-quality images encompassing old classes. Additionally, we adopt an L2 knowledge distillation technique to improve the retention of prior knowledge in synthetic images. Furthermore, our approach includes pseudo-labeling for old objects within new task images, preventing misclassification as background elements. Extensive experiments on the COCO 2017 dataset demonstrate that SD-DGR significantly outperforms existing algorithms, achieving a new state-of-the-art in various CIOD scenarios.

Facial expression recognition (FER) has greatly benefited from deep learning but still faces challenges in dataset collection due to the nuanced nature of facial expressions. In this study, we present a novel unlabeled dataset and semi-supervised contrastive learning framework that utilizes Reaction Mashup (RM) videos, a video that includes multiple individuals reacting to the same film. We created a Reaction Mashup dataset (RMset) from these videos. Our framework integrates three distinct modules: A classification module for supervised facial expression categorization, an attention module for inter-sample attention learning, and a contrastive module for attention-based contrastive learning using RMset. We utilize both the classification and attention modules for the initial training, subsequently incorporating the contrastive module to enhance the learning process. Our experiments demonstrate that our method improves feature learning and outperforms state-of-the-art models on three benchmark FER datasets. Codes are available at https://github.com/yunseongcho/RMFER.

Understanding the hand-object interactions from an egocentric video has received a great attention recently. So far, most approaches are based on the convolutional neural network (CNN) features combined with the temporal encoding via the long shortterm memory (LSTM) or graph convolution network (GCN) to provide the unified understanding of two hands, an object and their interactions. In this paper, we propose the Transformer-based unified framework that provides better understanding of two hands manipulating objects. In our framework, we insert the whole image depicting two hands, an object and their interactions as input and jointly estimate 3 information from each frame: poses of two hands, pose of an object and object types. Afterwards, the action class defined by the hand-object interactions is predicted from the entire video based on the estimated information combined with the contact map that encodes the interaction between two hands and an object. Experiments are conducted on H2O and FPHA benchmark datasets and we demonstrated the superiority of our method achieving the state-of-the-art accuracy. Ablative studies further demonstrate the effectiveness of each proposed module.