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Wenxuan Cai

Publications and source records attributed to Wenxuan Cai.

3 recordsLinked to original sources

TaskIR: Task-Driven Image Restoration via Degradation Adaptation and Task Feedback

Task-driven image restoration aims to improve both image quality and downstream task performance. However, existing methods predominantly focus on single degradation type and struggle to handle the diverse degradations encountered in real-world scenarios. Different degradations impose distinct restoration demands, and insufficient restoration may leave residual degradations and artifacts that impair object boundaries and semantic cues, thereby compromising downstream task performance. To address these challenges, we propose TaskIR, a two-stage task-driven unified image restoration framework that integrates degradation-adaptive restoration with task feedback refinement. In Stage I, a Degradation Representation Module (DRM) extracts degradation representations, enabling a Degradation-Guided Transformer Block (DGTB) to dynamically modulate feature transformations for adaptive restoration. In Stage II, a Task-to-Restoration Feedback Generation module (TRFG) transforms heterogeneous task features into restoration feedback by modeling task-representation discrepancies associated with the current restoration. Subsequently, a Selective Task Feedback Refinement module (STFR) assesses feedback relevance and selectively refines intermediate restoration features to mitigate interference with well-restored content. Extensive experiments demonstrate that TaskIR achieves competitive restoration quality and downstream task performance across diverse degradations and tasks.

cs.CV↗

NTIRE 2025 Challenge on Image Super-Resolution (x4): Methods and Results

This paper presents the NTIRE 2025 image super-resolution ($\times$4) challenge, one of the associated competitions of the 10th NTIRE Workshop at CVPR 2025. The challenge aims to recover high-resolution (HR) images from low-resolution (LR) counterparts generated through bicubic downsampling with a $\times$4 scaling factor. The objective is to develop effective network designs or solutions that achieve state-of-the-art SR performance. To reflect the dual objectives of image SR research, the challenge includes two sub-tracks: (1) a restoration track, emphasizes pixel-wise accuracy and ranks submissions based on PSNR; (2) a perceptual track, focuses on visual realism and ranks results by a perceptual score. A total of 286 participants registered for the competition, with 25 teams submitting valid entries. This report summarizes the challenge design, datasets, evaluation protocol, the main results, and methods of each team. The challenge serves as a benchmark to advance the state of the art and foster progress in image SR.

cs.CV↗

Predicting core-level X-ray photoemission spectra of oxide surfaces from first principles -- a case study for SnO$_2$

X-ray photoemission spectroscopy (XPS) is a powerful technique to gain insight into the chemical properties of oxide surfaces. However, the interpretation of XPS spectra is notoriously difficult as realistic surfaces contain different terminations, reconstructions, adsorbates and defects all of which leave (potentially overlapping) spectroscopic fingerprints. To address this challenge, we present a first-principles approach based on the Z+1 method that allows us to predict XPS spectra of oxide surfaces which can directly be compared to experimental measurements. We present results for different SnO$_2$ (110) surfaces: the stoichiometric surface, surfaces with different types of vacancies (one of which is the fully reduced surface) and also the fully reduced surface with adsorbed OH and O$_2$ molecules. For these systems, we calculate the O 1s core-electron binding energies of all oxygen atoms and then use this to predict the XPS spectrum. We find that the fully reduced surface gives rise to a highly symmetric peak shape in agreement with recent XPS measurements. In contrast, the spectrum of the stoichiometric surface exhibits an additional feature at low binding energies caused by the bridging oxygen atoms at the surface. For the reduced surface with OH and O$_2$ adsorbates, the spectrum exhibits additional features at higher binding energies. The predicted spectra are in good agreement with experimental results obtained for reduced surfaces that have been exposed to oxygen gas. The presented method is general and can be straightforwardly applied to other surfaces.

cond-mat.mtrl-sci↗