仿真到真实

Most of the recent literature on image Super-Resolution (SR) can be classified into two main approaches. The first one involves learning a corruption model tailored to a specific dataset aiming to mimic the noise and corruption in low-resolution images such as sensor noise. However this approach is data-specific tends to lack adaptability and its accuracy diminishes when faced with unseen types of image corruptions. A second and more recent approach referred to as Robust Super-Resolution (RSR) proposes to improve real-world SR by harnessing the generalization capabilities of a model by making it robust to adversarial attacks. To delve further into this second approach our paper explores the universality of various methods for enhancing the robustness of deep learning SR models. In other words we inquire: \enquote Which robustness method exhibits the highest degree of adaptability when dealing with a wide range of adversarial attacks ? . Our extensive experimentation on both synthetic and real-world images empirically demonstrates that median randomized smoothing (MRS) is more general in terms of robustness compared to adversarial learning techniques which tend to focus on specific types of attacks. Furthermore as expected we also illustrate that the proposed universal robust method enables the SR model to handle standard corruptions more effectively such as blur and Gaussian noise and notably corruptions naturally present in real-world images. These results support the significance of shifting the paradigm in the development of real-world SR methods towards RSR especially via MRS.

Learning-based underwater image enhancement (UIE) methods have made great progress. However the lack of large-scale and high-quality paired training samples has become the main bottleneck hindering the development of UIE. The inter-frame information in underwater videos can accelerate or optimize the UIE process. Thus we constructed the first large-scale high-resolution underwater video enhancement benchmark (UVEB) to promote the development of underwater vision.It contains 1308 pairs of video sequences and more than 453000 high-resolution with 38% Ultra-High-Definition (UHD) 4K frame pairs. UVEB comes from multiple countries containing various scenes and video degradation types to adapt to diverse and complex underwater environments. We also propose the first supervised underwater video enhancement method UVE-Net. UVE-Net converts the current frame information into convolutional kernels and passes them to adjacent frames for efficient inter-frame information exchange. By fully utilizing the redundant degraded information of underwater videos UVE-Net completes video enhancement better. Experiments show the effective network design and good performance of UVE-Net.

Existing photorealistic relightable hand models require extensive identity-specific observations in different views poses and illuminations and face challenges in generalizing to natural illuminations and novel identities. To bridge this gap we present URHand the first universal relightable hand model that generalizes across viewpoints poses illuminations and identities. Our model allows few-shot personalization using images captured with a mobile phone and is ready to be photorealistically rendered under novel illuminations. To simplify the personalization process while retaining photorealism we build a powerful universal relightable prior based on neural relighting from multi-view images of hands captured in a light stage with hundreds of identities. The key challenge is scaling the cross-identity training while maintaining personalized fidelity and sharp details without compromising generalization under natural illuminations. To this end we propose a spatially varying linear lighting model as the neural renderer that takes physics-inspired shading as input feature. By removing non-linear activations and bias our specifically designed lighting model explicitly keeps the linearity of light transport. This enables single-stage training from light-stage data while generalizing to real-time rendering under arbitrary continuous illuminations across diverse identities. In addition we introduce the joint learning of a physically based model and our neural relighting model which further improves fidelity and generalization. Extensive experiments show that our approach achieves superior performance over existing methods in terms of both quality and generalizability. We also demonstrate quick personalization of URHand from a short phone scan of an unseen identity.

3D pose transfer that aims to transfer the desired pose to a target mesh is one of the most challenging 3D generation tasks. Previous attempts rely on well-defined parametric human models or skeletal joints as driving pose sources. However to obtain those clean pose sources cumbersome but necessary pre-processing pipelines are inevitable hindering implementations of the real-time applications. This work is driven by the intuition that the robustness of the model can be enhanced by introducing adversarial samples into the training leading to a more invulnerable model to the noisy inputs which even can be further extended to directly handling the real-world data like raw point clouds/scans without intermediate processing. Furthermore we propose a novel 3D pose Masked Autoencoder (3D-PoseMAE) a customized MAE that effectively learns 3D extrinsic presentations (i.e. pose). 3D-PoseMAE facilitates learning from the aspect of extrinsic attributes by simultaneously generating adversarial samples that perturb the model and learning the arbitrary raw noisy poses via a multi-scale masking strategy. Both qualitative and quantitative studies show that the transferred meshes given by our network result in much better quality. Besides we demonstrate the strong generalizability of our method on various poses different domains and even raw scans. Experimental results also show meaningful insights that the intermediate adversarial samples generated in the training can successfully attack the existing pose transfer models.

We present SplattingAvatar a hybrid 3D representation of photorealistic human avatars with Gaussian Splatting embedded on a triangle mesh which renders over 300 FPS on a modern GPU and 30 FPS on a mobile device. We disentangle the motion and appearance of a virtual human with explicit mesh geometry and implicit appearance modeling with Gaussian Splatting. The Gaussians are defined by barycentric coordinates and displacement on a triangle mesh as Phong surfaces. We extend lifted optimization to simultaneously optimize the parameters of the Gaussians while walking on the triangle mesh. SplattingAvatar is a hybrid representation of virtual humans where the mesh represents low-frequency motion and surface deformation while the Gaussians take over the high-frequency geometry and detailed appearance. Unlike existing deformation methods that rely on an MLP-based linear blend skinning (LBS) field for motion we control the rotation and translation of the Gaussians directly by mesh which empowers its compatibility with various animation techniques e.g. skeletal animation blend shapes and mesh editing. Trainable from monocular videos for both full-body and head avatars SplattingAvatar shows state-of-the-art rendering quality across multiple datasets.

Novel view synthesis of dynamic scenes has been an intriguing yet challenging problem. Despite recent advancements simultaneously achieving high-resolution photorealistic results real-time rendering and compact storage remains a formidable task. To address these challenges we propose Spacetime Gaussian Feature Splatting as a novel dynamic scene representation composed of three pivotal components. First we formulate expressive Spacetime Gaussians by enhancing 3D Gaussians with temporal opacity and parametric motion/rotation. This enables Spacetime Gaussians to capture static dynamic as well as transient content within a scene. Second we introduce splatted feature rendering which replaces spherical harmonics with neural features. These features facilitate the modeling of view- and time-dependent appearance while maintaining small size. Third we leverage the guidance of training error and coarse depth to sample new Gaussians in areas that are challenging to converge with existing pipelines. Experiments on several established real-world datasets demonstrate that our method achieves state-of-the-art rendering quality and speed while retaining compact storage. At 8K resolution our lite-version model can render at 60 FPS on an Nvidia RTX 4090 GPU.

Creating high-quality 3D models of clothed humans from single images for real-world applications is crucial. Despite recent advancements accurately reconstructing humans in complex poses or with loose clothing from in-the-wild images along with predicting textures for unseen areas remains a significant challenge. A key limitation of previous methods is their insufficient prior guidance in transitioning from 2D to 3D and in texture prediction. In response we introduce SIFU (Side-view Conditioned Implicit Function for Real-world Usable Clothed Human Reconstruction) a novel approach combining a Side-view Decoupling Transformer with a 3D Consistent Texture Refinement pipeline. SIFU employs a cross-attention mechanism within the transformer using SMPL-X normals as queries to effectively decouple side-view features in the process of mapping 2D features to 3D. This method not only improves the precision of the 3D models but also their robustness especially when SMPL-X estimates are not perfect. Our texture refinement process leverages text-to-image diffusion-based prior to generate realistic and consistent textures for invisible views. Through extensive experiments SIFU surpasses SOTA methods in both geometry and texture reconstruction showcasing enhanced robustness in complex scenarios and achieving an unprecedented Chamfer and P2S measurement. Our approach extends to practical applications such as 3D printing and scene building demonstrating its broad utility in real-world scenarios.

With advancements in domain generalized stereo matching networks models pre-trained on synthetic data demonstrate strong robustness to unseen domains. However few studies have investigated the robustness after fine-tuning them in real-world scenarios during which the domain generalization ability can be seriously degraded. In this paper we explore fine-tuning stereo matching networks without compromising their robustness to unseen domains. Our motivation stems from comparing Ground Truth (GT) versus Pseudo Label (PL) for fine-tuning: GT degrades but PL preserves the domain generalization ability. Empirically we find the difference between GT and PL implies valuable information that can regularize networks during fine-tuning. We also propose a framework to utilize this difference for fine-tuning consisting of a frozen Teacher an exponential moving average (EMA) Teacher and a Student network. The core idea is to utilize the EMA Teacher to measure what the Student has learned and dynamically improve GT and PL for fine-tuning. We integrate our framework with state-of-the-art networks and evaluate its effectiveness on several real-world datasets. Extensive experiments show that our method effectively preserves the domain generalization ability during fine-tuning.

Active Domain Adaptation (ADA) aims to maximally boost model adaptation in a new target domain by actively selecting a limited number of target data to annotate. This setting neglects the more practical scenario where training data are collected from multiple sources. This motivates us to extend ADA from a single source domain to multiple source domains termed Multi-source Active Domain Adaptation (MADA). Not surprisingly we find that most traditional ADA methods cannot work directly in such a setting mainly due to the excessive domain gap introduced by all the source domains. Considering this we propose a Detective framework that comprehensively considers the domain shift between multi-source domains and target domains to detect the informative target samples. Specifically the Detective leverages a dynamic Domain Adaptation (DA) model that learns how to adapt the model's parameters to fit the union of multi-source domains. This enables an approximate single-source domain modeling by the dynamic model. We then comprehensively measure both domain uncertainty and predictive uncertainty in the target domain to detect informative target samples using evidential deep learning thereby mitigating uncertainty miscalibration. Experiments demonstrate that our solution outperforms existing methods by a considerable margin on three domain adaptation benchmarks.

The fidelity of relighting is bounded by both geometry and appearance representations. For geometry both mesh and volumetric approaches have difficulty modeling intricate structures like 3D hair geometry. For appearance existing relighting models are limited in fidelity and often too slow to render in real-time with high-resolution continuous environments. In this work we present Relightable Gaussian Codec Avatars a method to build high-fidelity relightable head avatars that can be animated to generate novel expressions. Our geometry model based on 3D Gaussians can capture 3D-consistent sub-millimeter details such as hair strands and pores on dynamic face sequences. To support diverse materials of human heads such as the eyes skin and hair in a unified manner we present a novel relightable appearance model based on learnable radiance transfer. Together with global illumination-aware spherical harmonics for the diffuse components we achieve real-time relighting with all-frequency reflections using spherical Gaussians. This appearance model can be efficiently relit under both point light and continuous illumination. We further improve the fidelity of eye reflections and enable explicit gaze control by introducing relightable explicit eye models. Our method outperforms existing approaches without compromising real-time performance. We also demonstrate real-time relighting of avatars on a tethered consumer VR headset showcasing the efficiency and fidelity of our avatars.

Text-to-image customization which aims to synthesize text-driven images for the given subjects has recently revolutionized content creation. Existing works follow the pseudo-word paradigm i.e. represent the given subjects as pseudo-words and then compose them with the given text. However the inherent entangled influence scope of pseudo-words with the given text results in a dual-optimum paradox i.e. the similarity of the given subjects and the controllability of the given text could not be optimal simultaneously. We present RealCustom that for the first time disentangles similarity from controllability by precisely limiting subject influence to relevant parts only achieved by gradually narrowing real text word from its general connotation to the specific subject and using its cross-attention to distinguish relevance. Specifically RealCustom introduces a novel "train-inference" decoupled framework: (1) during training RealCustom learns general alignment between visual conditions to original textual conditions by a novel adaptive scoring module to adaptively modulate influence quantity; (2) during inference a novel adaptive mask guidance strategy is proposed to iteratively update the influence scope and influence quantity of the given subjects to gradually narrow the generation of the real text word. Comprehensive experiments demonstrate the superior real-time customization ability of RealCustom in the open domain achieving both unprecedented similarity of the given subjects and controllability of the given text for the first time. The project page is https://corleone-huang.github.io/realcustom/.

We propose a novel framework for real-time acquisition and reconstruction of temporally-varying 3D phenomena with high quality. The core of our framework is a deep neural network with an encoder that directly maps to the structured illumination during acquisition a decoder that predicts a 1D density distribution from single-pixel measurements under the optimized lighting and an aggregation module that combines the predicted densities for each camera into a single volume. It enables the automatic and joint optimization of physical acquisition and computational reconstruction and is flexible to adapt to different hardware configurations. The effectiveness of our framework is demonstrated on a lightweight setup with an off-the-shelf projector and one or multiple cameras achieving a performance of 40 volumes per second at a spatial resolution of 128^3. We compare favorably with state-of-the-art techniques in real and synthetic experiments and evaluate the impact of various factors over our pipeline.

As recent advances in mobile camera technology have enabled the capability to capture high-resolution images such as 4K images the demand for an efficient deblurring model handling large motion has increased. In this paper we discover that the image residual errors i.e. blur-sharp pixel differences can be grouped into some categories according to their motion blur type and how complex their neighboring pixels are. Inspired by this we decompose the deblurring (regression) task into blur pixel discretization (pixel-level blur classification) and discrete-to-continuous conversion (regression with blur class map) tasks. Specifically we generate the discretized image residual errors by identifying the blur pixels and then transform them to a continuous form which is computationally more efficient than naively solving the original regression problem with continuous values. Here we found that the discretization result i.e. blur segmentation map remarkably exhibits visual similarity with the image residual errors. As a result our efficient model shows comparable performance to state-of-the-art methods in realistic benchmarks while our method is up to 10 times computationally more efficient.

We present SimXR a method for controlling a simulated avatar from information (headset pose and cameras) obtained from AR / VR headsets. Due to the challenging viewpoint of head-mounted cameras the human body is often clipped out of view making traditional image-based egocentric pose estimation challenging. On the other hand headset poses provide valuable information about overall body motion but lack fine-grained details about the hands and feet. To synergize headset poses with cameras we control a humanoid to track headset movement while analyzing input images to decide body movement. When body parts are seen the movements of hands and feet will be guided by the images; when unseen the laws of physics guide the controller to generate plausible motion. We design an end-to-end method that does not rely on any intermediate representations and learns to directly map from images and headset poses to humanoid control signals. To train our method we also propose a large-scale synthetic dataset created using camera configurations compatible with a commercially available VR headset (Quest 2) and show promising results on real-world captures. To demonstrate the applicability of our framework we also test it on an AR headset with a forward-facing camera.

We propose a neural reflectance model (NeuBRDF) that offers highly versatile material representation yet with light memory and neural computation consumption towards achieving real-time rendering. The results depicted in Fig. 1 rendered at full HD resolution on a contemporary desktop machine demonstrate that our system achieves real-time performance with a wide variety of appearances which is approached by the following two designs. Firstly recognizing that the bidirectional reflectance is distributed in a sparse high-dimensional space we propose to project the BRDF into two low-dimensional components i.e. two hemisphere feature-grids for incoming and outgoing directions respectively. Secondly we distribute learnable neural reflectance primitives on our highly-tailored spherical surface grid. These primitives offer informative features for each hemisphere component and reduce the complexity of the feature learning network leading to fast evaluation. These primitives are centrally stored in a codebook and can be shared across multiple grids and even across materials based on low-cost indices stored in material-specific spherical surface grids. Our NeuBRDF agnostic to the material provides a unified framework for representing a variety of materials consistently. Comprehensive experimental results on measured BRDF compression Monte Carlo simulated BRDF acceleration and extension to spatially varying effects demonstrate the superior quality and generalizability achieved by the proposed scheme.

Most of the previous exposure correction methods learn dense pixel-wise transformations to achieve promising results but consume huge computational resources. Recently Learnable 3D lookup tables (3D LUTs) have demonstrated impressive performance and efficiency for image enhancement. However these methods can only perform global transformations and fail to finely manipulate local regions. Moreover they uniformly downsample the input image which loses the rich color information and limits the learning of color transformation capabilities. In this paper we present a collaborative transformation framework (CoTF) for real-time exposure correction which integrates global transformation with pixel-wise transformations in an efficient manner. Specifically the global transformation adjusts the overall appearance using image-adaptive 3D LUTs to provide decent global contrast and sharp details while the pixel transformation compensates for local context. Then a relation-aware modulation module is designed to combine these two components effectively. In addition we propose an adaptive sampling strategy to preserve more color information by predicting the sampling intervals thus providing higher quality input data for the learning of 3D LUTs. Extensive experiments demonstrate that our method can process high-resolution images in real-time on GPUs while achieving comparable performance against current state-of-the-art methods. The code is available at https://github.com/HUST-IAL/CoTF.

Object detection in radar imagery with neural networks shows great potential for improving autonomous driving. However obtaining annotated datasets from real radar images crucial for training these networks is challenging especially in scenarios with long-range detection and adverse weather and lighting conditions where radar performance excels. To address this challenge we present RadSimReal an innovative physical radar simulation capable of generating synthetic radar images with accompanying annotations for various radar types and environmental conditions all without the need for real data collection. Remarkably our findings demonstrate that training object detection models on RadSimReal data and subsequently evaluating them on real-world data produce performance levels comparable to models trained and tested on real data from the same dataset and even achieves better performance when testing across different real datasets. RadSimReal offers advantages over other physical radar simulations that it does not necessitate knowledge of the radar design details which are often not disclosed by radar suppliers and has faster run-time. This innovative tool has the potential to advance the development of computer vision algorithms for radar-based autonomous driving applications.

Real-time multi-person pose estimation presents significant challenges in balancing speed and precision. While two-stage top-down methods slow down as the number of people in the image increases existing one-stage methods often fail to simultaneously deliver high accuracy and real-time performance. This paper introduces RTMO a one-stage pose estimation framework that seamlessly integrates coordinate classification by representing keypoints using dual 1-D heatmaps within the YOLO architecture achieving accuracy comparable to top-down methods while maintaining high speed. We propose a dynamic coordinate classifier and a tailored loss function for heatmap learning specifically designed to address the incompatibilities between coordinate classification and dense prediction models. RTMO outperforms state-of-the-art one-stage pose estimators achieving 1.1% higher AP on COCO while operating about 9 times faster with the same backbone. Our largest model RTMO-l attains 74.8% AP on COCO val2017 and 141 FPS on a single V100 GPU demonstrating its efficiency and accuracy. The code and models are available at https://github.com/open-mmlab/mmpose/tree/main/projects/rtmo.

The value of roadside perception which could extend the boundaries of autonomous driving and traffic management has gradually become more prominent and acknowledged in recent years. However existing roadside perception approaches only focus on the single-infrastructure sensor system which cannot realize a comprehensive understanding of a traffic area because of the limited sensing range and blind spots. Orienting high-quality roadside perception we need Roadside Cooperative Perception (RCooper) to achieve practical area-coverage roadside perception for restricted traffic areas. Rcooper has its own domain-specific challenges but further exploration is hindered due to the lack of datasets. We hence release the first real-world large-scale RCooper dataset to bloom the research on practical roadside cooperative perception including detection and tracking. The manually annotated dataset comprises 50k images and 30k point clouds including two representative traffic scenes (i.e. intersection and corridor). The constructed benchmarks prove the effectiveness of roadside cooperation perception and demonstrate the direction of further research. Codes and dataset can be accessed at: https://github.com/AIR-THU/DAIR-RCooper.

This paper focuses on advancing the applicability of human avatar learning methods by proposing RAM-Avatar which learns a Real-time photo-realistic Avatar that supports full-body control from Monocular videos. To achieve this goal RAM-Avatar leverages two statistical templates responsible for modeling the facial expression and hand gesture variations while a sparsely computed dual attention module is introduced upon another body template to facilitate high-fidelity texture rendering for the torsos and limbs. Building on this foundation we deploy a lightweight yet powerful StyleUnet along with a temporal-aware discriminator to achieve real-time realistic rendering. To enable robust animation for out-of-distribution poses we propose a Motion Distribution Align module to compensate for the discrepancies between the training and testing motion distribution. Results and extensive experiments conducted in various experimental settings demonstrate the superiority of our proposed method and a real-time live system is proposed to further push research into applications. The training and testing code will be released for research purposes.