Li Xu 0008

dblp:85/2168-8 · DBLP profile ↗
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10ranked-venue papers
2as first author
10since 2021 · last 2026
0000-0002-4865-7904ORCID · conflict

Domains — the database's venue-derived domains; a paper can count in several

Graphics, computer vision, multimedia, augmented reality and games · 8 · 2 first-author · 8 since 2021Artificial intelligence and machine learning · 6 · 2 first-author · 6 since 2021Databases, data management, data science and information retrieval · 1 · 1 since 2021
YearPublicationVenuePosition
2026 RealRep: Generalized SDR-to-HDR Conversion via Attribute-Disentangled Representation Learning
abstract
High-Dynamic-Range Wide-Color-Gamut (HDR-WCG) technology is becoming increasingly widespread, driving a growing need for converting Standard Dynamic Range (SDR) content to HDR. Existing methods primarily rely on fixed tone mapping operators, which struggle to handle the diverse appearances and degradations commonly present in real-world SDR content. To address this limitation, we propose a generalized SDR-to-HDR framework that enhances robustness by learning attribute-disentangled representations. Central to our approach is Realistic Attribute-Disentangled Representation Learning (RealRep), which explicitly disentangles luminance and chrominance components to capture intrinsic content variations across different SDR distributions. Furthermore, we design a Luma-/Chroma-aware negative exemplar generation strategy that constructs degradation-sensitive contrastive pairs, effectively modeling tone discrepancies across SDR styles. Building on these attribute-level priors, we introduce the Degradation-Domain Aware Controlled Mapping Network (DDACMNet), a lightweight, two-stage framework that performs adaptive hierarchical mapping guided by a control-aware normalization mechanism. DDACMNet dynamically modulates the mapping process via degradation-conditioned features, enabling robust adaptation across diverse degradation domains. Extensive experiments demonstrate that RealRep consistently outperforms state-of-the-art methods in both generalization and perceptually faithful HDR color gamut reconstruction.
Li Xu 0008, Kepeng Xu, Lin Zhang 0040, Gang He 0002, Yu-Wing Tai
AAAI1
2026 An All-in-One Quality Assessment Agent for 4D digital human: Bridging talking heads and animated human
Yingjie Zhou 0003, Farong Wen, Li Xu 0008, Yu Zhou 0016, Jiezhang Cao, Xiaohong Liu 0001, Xiongkuo Min, Yu Wang 0002, Guangtao Zhai
Inf. Process. Manag.4
2025 Beyond Feature Mapping GAP: Integrating Real HDRTV Priors for Superior SDRTV-to-HDRTV Conversion
abstract
The rise of HDR-WCG display devices has highlighted the need to convert SDRTV to HDRTV, as most video sources are still in SDR. Existing methods primarily focus on designing neural networks to learn a single-style mapping from SDRTV to HDRTV. However, the limited information in SDRTV and the diversity of styles in real-world conversions render this process an ill-posed problem, thereby constraining the performance and generalization of these methods. Inspired by generative approaches, we propose a novel method for SDRTV to HDRTV conversion guided by real HDRTV priors. Despite the limited information in SDRTV, introducing real HDRTV as reference priors significantly constrains the solution space of the originally high-dimensional ill-posed problem. This shift transforms the task from solving an unreferenced prediction problem to making a referenced selection, thereby markedly enhancing the accuracy and reliability of the conversion process. Specifically, our approach comprises two stages: the first stage employs a Vector Quantized Generative Adversarial Network to capture HDRTV priors, while the second stage matches these priors to the input SDRTV content to recover realistic HDRTV outputs. We evaluate our method on public datasets, demonstrating its effectiveness with significant improvements in both objective and subjective metrics across real and synthetic datasets.
Gang He 0002, Kepeng Xu, Li Xu 0008, Wenxin Yu 0001, Xianyun Wu
IJCAI3
2025 Unleashing the Potential of Transformer Flow for Photorealistic Face Restoration
abstract
Face restoration is a challenging task due to the need to remove artifacts and restore details. Traditional methods usually use generative model prior to achieve face restoration, but the restored results are still insufficient in terms of realism and details. In this paper, we introduce OmniFace, a novel face restoration framework that leverages Transformer-based diffusion flow. By exploiting the scaling property of Transformer, OmniFace achieves high-resolution restoration with exceptional realism and detail. The framework integrates three key components: (1) a Transformer-driven vector estimation network, (2) a representation aligned ControlNet, and (3) an adaptive training strategy for face restoration. The inherent scaling law of Transformer architectures enables the restoration of high-quality faces at high resolution. The controlnet combined with pre-trained diffusion representation can be easily trained. The adaptive training strategy provides a vector field that is more suitable for face restoration. Comprehensive experiments demonstrate that OmniFace outperforms existing techniques in terms of restoration quality across multiple benchmark datasets, especially in restoring photographic-level texture details in high-resolution scenes.
Kepeng Xu, Li Xu 0008, Gang He 0002, Wei Chen 0062, Xianyun Wu, Wenxin Yu 0001
IJCAI2
2024 Beyond Alignment: Blind Video Face Restoration via Parsing-Guided Temporal-Coherent Transformer
Kepeng Xu, Li Xu 0008, Gang He 0002, Wenxin Yu 0001, Yunsong Li 0001
IJCAI2
2024 An End-to-End Real-World Camera Imaging Pipeline
abstract
pipeline still faces challenges including the lack of joint optimization in system components, computational redundancies, and optical distortions such as lens shading.In light of this, we propose an end-to-end camera imaging pipeline (RealCamNet) to enhance realworld camera imaging performance.Our methodology diverges from conventional, fragmented multi-stage image signal processing towards end-to-end architecture.This architecture facilitates joint optimization across the full pipeline and the restoration of coordinate-biased distortions.RealCamNet is designed for highquality conversion from RAW to RGB and compact image compression.Specifically, we deeply analyze coordinate-dependent optical distortions, e.g., vignetting and dark shading, and design a novel 2804
Kepeng Xu, Zijia Ma, Li Xu 0008, Gang He 0002, Yunsong Li 0001, Wenxin Yu 0001, Taichu Han, Cheng Yang 0016
ACM Multimedia3
2023 Global priors guided modulation network for joint super-resolution and SDRTV-to-HDRTV
abstract
Watching low resolution standard dynamic range (LR SDR) video on a 4K high dynamic range (HDR) TV is not the best viewing experience. Joint super-resolution (SR) and SDRTV-to-HDRTV aims to enhance the visual quality of LR SDR videos that have quality deficiencies in resolution and dynamic range. Previous methods that rely on learning local information typically cannot do well in preserving color conformity and long-range structural similarity, resulting in unnatural color transition and texture artifacts. In order to tackle these challenges, we propose a global priors guided modulation network (GPGMNet). In particular, we design a global priors extraction module (GPEM) to extract color conformity prior and structural similarity prior that are beneficial for SDRTV-to-HDRTV and SR tasks, respectively. To further exploit the global priors and preserve spatial information, we devise multiple global priors-guided spatial-wise modulation blocks (GSMBs) with a few parameters for intermediate feature modulation. In these GSMBs, the modulation parameters are generated by the shared global priors and the spatial features map from the spatial pyramid convolution block (SPCB). With these elaborate designs, the GPGMNet can achieve higher visual quality with lower computational complexity. Extensive experiments demonstrate that our proposed GPGMNet is superior to the state-of-the-art methods. Specifically, our proposed model exceeds the state-of-the-art by 0.64 dB in PSNR, with 69% fewer parameters and 3.1 × speedup.
Gang He 0002, Shaoyi Long, Li Xu 0008, Chang Wu 0001, Wenxin Yu 0001, Jinjia Zhou
Neurocomputing3
2022 Transcoded Video Restoration by Temporal Spatial Auxiliary Network
abstract
In most video platforms, such as Youtube, Kwai, and TikTok, the played videos usually have undergone multiple video encodings such as hardware encoding by recording devices, software encoding by video editing apps, and single/multiple video transcoding by video application servers. Previous works in compressed video restoration typically assume the compression artifacts are caused by one-time encoding. Thus, the derived solution usually does not work very well in practice. In this paper, we propose a new method, temporal spatial auxiliary network (TSAN), for transcoded video restoration. Our method considers the unique traits between video encoding and transcoding, and we consider the initial shallow encoded videos as the intermediate labels to assist the network to conduct self-supervised attention training. In addition, we employ adjacent multi-frame information and propose the temporal deformable alignment and pyramidal spatial fusion for transcoded video restoration. The experimental results demonstrate that the performance of the proposed method is superior to that of the previous techniques. The code is available at https://github.com/icecherylXuli/TSAN.
Li Xu 0008, Gang He 0002, Jinjia Zhou, Jie Lei 0001, Weiying Xie, Yunsong Li 0001, Yu-Wing Tai
AAAI1
2022 SDRTV-to-HDRTV via Hierarchical Dynamic Context Feature Mapping
abstract
In this work, we address the task of SDR videos to HDR videos(SDRTV-to-HDRTV conversion). Previous approaches use global feature modulation for SDRTV-to-HDRTV conversion. Feature modulation scales and shifts the features in the original feature space, which has limited mapping capability. In addition, the global image mapping cannot restore detail in HDR frames due to the luminance differences in different regions of SDR frames. To resolve the appeal, we propose a two-stage solution. The first stage is a hierarchical Dynamic Context feature mapping (HDCFM) model. HDCFM learns the SDR frame to HDR frame mapping function via hierarchical feature modulation (HME and HM ) module and a dynamic context feature transformation (DYCT) module. The HME estimates the feature modulation vector, HM is capable of hierarchical feature modulation, consisting of global feature modulation in series with local feature modulation, and is capable of adaptive mapping of local image features. The DYCT module constructs a feature transformation module in conjunction with the context, which is capable of adaptively generating a feature transformation matrix for feature mapping. Compared with simple feature scaling and shifting, the DYCT module can map features into a new feature space and thus has a more excellent feature mapping capability. In the second stage, we introduce a patch discriminator-based context generation model PDCG to obtain subjective quality enhancement of over-exposed regions. The proposed method can achieve state-of-the-art objective and subjective quality results. Specifically, HDCFM achieves a PSNR gain of 0.81 dB at about 100K parameters. The number of parameters is 1/14th of the previous state-of-the-art methods. The test code will be released on https://github.com/cooperlike/HDCFM.
Gang He 0002, Kepeng Xu, Li Xu 0008, Chang Wu 0001, Ming Sun 0008, Yu-Wing Tai
ACM Multimedia3
2022 Interlayer Restoration Deep Neural Network for Scalable High Efficiency Video Coding
abstract
This paper applies an interlayer restoration deep neural network (IRDNN) for scalable high efficiency video coding (SHVC) to improve visual quality and coding efficiency. It is the first time to combine deep neural network (DNN) and SHVC. Considering the coding architecture of SHVC, we elaborate a multi-frame and multi-layer neural network to restore the interlayer of SHVC by utilizing both the adjacent reconstructed frames of the base layer (BL) and enhancement layer (EL). Moreover, we analyze the temporal motion relationship of frames in one layer and the compression degradation relationship of frames between different layers, and propose the synergistic mechanism of motion restoration and compression restoration in our IRDNN. The network can generate an interlayer with higher quality serving for the EL coding and thus enhance the coding efficiency. A large-scale and various-quality-degradation dataset is self-made for the task of interlayer restoration of SHVC. The experimental results show that with our implementation on SHVC, the EL Bj$\phi $ntegaard delta bit-rate (BD-BR) reduction is 9.291% and 6.007% in signal-to-noise ratio scalability and spatial scalability, respectively. The code is available athttps://github.com/icecherylXuli/IRDNN.
Gang He 0002, Li Xu 0008, Jie Lei 0001, Weiying Xie, Yunsong Li 0001, Yibo Fan, Jinjia Zhou
IEEE Trans. Circuits Syst. Video Technol.2