Object detection in low-light environments remains challenging due to severe image degradation, limited annotations, and the high cost of manual labeling. While traditional enhancement methods improve visual appearance, they often hinder detection performance. In this work, we propose a lightweight zero-shot enhancement network designed specifically for object detection, enabling effective illumination correction without requiring real low-light data. Unlike pixel-level restoration approaches, our method operates at the feature level, leveraging a physics-inspired model that extracts illumination-invariant representations via Lambertian reflectance and cross-channel chrominance ratios. To enhance global feature perception with minimal computational overhead, we introduce a frequency-domain branch based on complex convolutions, and fuse it adaptively with spatial-domain features through a dual-branch architecture. The proposed module is compact and detector-agnostic, and can be seamlessly integrated into existing frameworks. Extensive experiments show that our approach significantly improves detection performance under low-light conditions, achieving a 4.6% mAP gain on ExDark and a 2.7% improvement on DarkFace.

Continuous-Time Dynamic Graph (CTDG) precisely models evolving real-world relationships, drawing heightened interest in dynamic graph learning across academia and industry. However, existing CTDG models encounter challenges stemming from noise and limited historical data. Graph Data Augmentation (GDA) emerges as a critical solution, yet current approaches primarily focus on static graphs and struggle to effectively address the dynamics inherent in CTDGs. Moreover, these methods often demand substantial domain expertise for parameter tuning and lack theoretical guarantees for augmentation efficacy. To address these issues, we propose Conda, a novel latent diffusion-based GDA method tailored for CTDGs. Conda features a sandwich-like architecture, incorporating a Variational Auto-Encoder (VAE) and a conditional diffusion model, aimed at generating enhanced historical neighbor embeddings for target nodes. Unlike conventional diffusion models trained on entire graphs via pre-training, Conda requires historical neighbor sequence embeddings of target nodes for training, thus facilitating more targeted augmentation. We integrate Conda into the CTDG model and adopt an alternating training strategy to optimize performance. Extensive experimentation across six widely used real-world datasets showcases the consistent performance improvement of our approach, particularly in scenarios with limited historical data.

Cross-modal image-text retrieval is a fundamental task in information retrieval. The key to this task is to address both heterogeneity and cross-modal semantic correlation between data of different modalities. Fine-grained matching methods can nicely model local semantic correlations between image and text but face two challenges. First, images may contain redundant information while text sentences often contain words without semantic meaning. Such redundancy interferes with the local matching between textual words and image regions. Furthermore, the retrieval shall consider not only low-level semantic correspondence between image regions and textual words but also a higher semantic correlation between different intra-modal relationships. We propose a multi-layer graph convolutional network with object-level, object-relational-level, and higher-level learning sub-networks. Our method learns hierarchical semantic correspondences by both local and global alignment. We further introduce a self-attention mechanism after the word embedding to weaken insignificant words in the sentence and a cross-attention mechanism to guide the learning of image features. Extensive experiments on Flickr30K and MS-COCO datasets demonstrate the effectiveness and superiority of our proposed method.

Automatic image colorization without manual interventions is an ill-conditioned and inherently ambiguous problem. Most of existing methods focus on formulating colorization as a regression problem and learn parametric mappings from grayscale to color through deep neural networks. Due to the multimodalities of color-grayscale space, in many applications, it is not required to recover exact ground-truth color. Pair-wise pixel-to-pixel learning-based algorithms lack rationality. Techniques such as color space conversion techniques are then proposed to avoid such direct pixel learning. However, the coloring results after color space conversion are blunt and unnatural. In this paper, we hold viewpoints that a reasonable solution is to generate some colorized result that looks natural. No matter what color a region is to be assigned, the colorized region should be semantically and spatially consistent. In this paper, we propose an effective semantic-aware automatic colorization model via unpaired cycle-consistent self-supervised network. Low-level monochrome loss, perceptual identity loss and high-level semantic-consistence loss, together with adversarial loss, are introduced to guide network self-training. We train and test our model on randomly selected subsets from PASCAL VOC 2012. The experimental results including human subjective studies demonstrate that, compared with state-of-the-art methods, our proposed model can achieve more convincing and superior results. Relevant source code is available at https://github.com/YuSuen/ACCycleGAN.