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Zhankai Li, Weiping Wang, Jie Li, Shigeng Zhang, Yunan Hu, Song Guo

In the field of AI security, deep neural networks (DNNs) are highly sensitive to adversarial examples (AEs), which can cause incorrect predictions with minimal input perturbations. Although AEs exhibit transferability across models, targeted attack success rates (TASRs) are low due to differences in feature dimensions and decision boundaries. To enhance targeted AE transferability, we propose a novel approach using Inverse Target Gradient Competition (ITC) and Spatial Distance Stretching (SDS) in the optimization process. Specifically, we employ a siamese-network-like framework to generate both non-targeted and targeted AEs. The ITC mechanism applies non-targeted adversarial gradients each epoch to impede the optimization of targeted perturbations, thereby improving robustness. Additionally, a top-k SDS strategy guides AEs to penetrate target class regions in the latent space while distancing from non-targeted regions, achieving optimal transferability. Compared to state-of-the-art competition-based attacks, our method significantly improves transferable TASRs by 16.1% and 21.4% on mainstream CNNs and ViTs, respectively, and demonstrates superior defense-breaking capabilities.

Xiaobiao Du, Yida Wang, Haiyang Sun, Zhuojie Wu, Hongwei Sheng, Shuyun Wang, Jiaying Ying, Ming Lu, Tianqing Zhu, Kun Zhan 等

3D cars are widely used in self-driving systems, virtual and augmented reality, and gaming applications. However, existing 3D car datasets are either synthetic or low-quality, limiting their practical utility and leaving a significant gap with the high-quality real-world 3D car dataset. In this paper, we present the first large-scale 3D real car dataset, termed 3DRealCar, which offers three key features: (1) High-Volume: 2,500 cars meticulously scanned using smartphones to capture RGB images and point clouds with real-world dimensions; (2) High-Quality: Each car is represented by an average of 200 dense, high-resolution 360-degree RGB-D views, enabling high-fidelity 3D reconstruction; (3) High-Diversity: The dataset encompasses a diverse collection of cars from over 100 brands, captured under three distinct lighting conditions (reflective, standard, and dark). We further provide detailed car parsing maps for each instance to facilitate research in automotive segmentation tasks. To focus on vehicles, background point clouds are removed, and all cars are aligned to a unified coordinate system, enabling controlled reconstruction and rendering. We benchmark state-of-the-art 3D reconstruction methods across different lighting conditions using 3DRealCar. Extensive experiments demonstrate that the standard lighting subset can be used to reconstruct high-quality 3D car models that significantly enhance performance on various car-related 2D and 3D tasks. Notably, our dataset reveals critical challenges faced by current 3D reconstruction methods under reflective and dark lighting conditions, providing valuable insights for future research.

Yingfan Ma, Bohan An, Ao Shen, Mingzhi Yuan, Minghong Duan, Manning Wang

Whole Slide Image (WSI) classification has been widely used in pathological diagnosis and prognosis prediction, and it is commonly formulated as a weakly-supervised Multiple Instance Learning (MIL) problem because of the large size of WSIs and the difficulty of obtaining fine-grained annotations. In the MIL formulation, a WSI is treated as a bag and the patches cut from it are treated as its instances, and most existing methods first extract instance features and then aggregate them into bag feature using attention-based mechanism for bag-level prediction. These models are trained using only bag-level labels, so they often lack instance-level insights and lose detailed semantic information, which limits their bag-level classification performance and damages their ability to explore high-expressive information. In this paper, we propose Flow-MIL, which leverages normalizing flow-based Latent Semantic Embedding Space (LSES) to enhance feature representation. By mapping patches into the simple and highly-expressive latent space LSES, Flow-MIL achieves effective slide-level aggregation while preserving critical semantic information. We also introduce Gaussian Mixture Model-based Latent Semantic Prototypes (LSP) within the LSES to capture class-specific pathological distribution for each class and refine pseudo instance labels. Extensive experiments on three public WSI datasets show that Flow-MIL outperforms recent SOTA methods in both bag-level and instance-level classification and offers improved interpretability.

Kim Kiehn, Albin Ahlbäck, Kathlén Kohn

We completely classify all minimal problems for Structure-from-Motion (SfM) where arrangements of points and lines are fully observed by multiple uncalibrated pinhole cameras. We find 291 minimal problems, 73 of which have unique solutions and can thus be solved linearly.Two of the linear problems allow an arbitrary number of views, while all other minimal problems have at most 9 cameras. All minimal problems have at most 7 points and at most 12 lines. We compute the number of solutions of each minimal problem, as this gives a measurement of the problem's intrinsic difficulty, and find that these number are relatively low (e.g., when comparing with minimal problems for calibrated cameras). Finally, by exploring stabilizer subgroups of subarrangements, we develop a geometric and systematic way to 1) factorize minimal problems into smaller problems, 2) identify minimal problems in underconstrained problems, and 3) formally prove non-minimality.

Chengbo Wang, Guozheng Ma, Yifei Xue, Yizhen Lao

3D Gaussian Splatting (3DGS) has emerged as a powerful technique for novel view synthesis, demonstrating remarkable capability in high-fidelity scene reconstruction through its Gaussian primitive representations. However, the computational overhead induced by the massive number of primitives poses a significant bottleneck to training efficiency. To overcome this challenge, we propose Group Training, a simple yet effective strategy that organizes Gaussian primitives into manageable groups, optimizing training efficiency and improving rendering quality. This approach shows universal compatibility with existing 3DGS frameworks, including vanilla 3DGS and Mip-Splatting, consistently achieving accelerated training while maintaining superior synthesis quality. Extensive experiments reveal that our straightforward Group Training strategy achieves up to 30% faster convergence and improved rendering quality across diverse scenarios. Project Website: https://chengbo-wang.github.io/3DGS-with-Group-Training/.

Maoxian Wan, Kaige Li, Qichuan Geng, Weimin Shi, Zhong Zhou

Existing incremental few-shot semantic segmentation (IFSS) methods often learn novel classes by fine-tuning parameters from previous stages. This inevitably reduces the distinguishability of old class features, leading to catastrophic forgetting and overfitting to limited new samples. In this paper, we propose a novel prompt-based IFSS method with a visual prompt pool to store and switch multi-granular knowledge across stages, enhancing the model's ability to learn new classes. Specifically, we introduce three levels of prompts: 1) Task-persistent prompts: capturing generalizable knowledge shared across stages, such as foreground-background distributions, to ensure consistent recognition guidance; 2) Stage-specific prompts: adapting to the unique requirements of each stage by integrating its discriminative knowledge (e.g., shape difference) with common knowledge from previous stages; and 3) Region-unique prompts: encoding category-specific structures (e.g., edges) to more accurately guide the model to retain local details. In particular, we introduce a prompt switching mechanism that adaptively allocates the knowledge required for base and new classes, avoiding interference between prompts and preventing catastrophic forgetting and reducing the increasing computation. Our method achieves a new state-of-the-art performance, outperforming previous SoTA methods by 30.28% mIoU-N on VOC and 13.90% mIoU-N on COCO under 1-shot setting. Code is available at https://github.com/WanMotion/MSVP.

Yufeng Jin, Vignesh Prasad, Snehal Jauhri, Mathias Franzius, Georgia Chalvatzaki

Efficient and accurate object pose estimation is an essential component for modern vision systems in many applications such as Augmented Reality, autonomous driving, and robotics. While research in model-based 6D object pose estimation has delivered promising results, model-free methods are hindered by the high computational load in rendering and inferring consistent poses of arbitrary objects in a live RGB-D video stream. To address this issue, we present 6DOPE-GS, a novel method for online 6D object pose estimation & tracking with a single RGB-D camera by effectively leveraging advances in Gaussian Splatting. Thanks to the fast differentiable rendering capabilities of Gaussian Splatting, 6DOPE-GS can simultaneously optimize for 6D object poses and 3D object reconstruction. To achieve the necessary efficiency and accuracy for live tracking, our method uses incremental 2D Gaussian Splatting with an intelligent dynamic keyframe selection procedure to achieve high spatial object coverage and prevent erroneous pose updates. We also propose an opacity statistic-based pruning mechanism for adaptive Gaussian density control, to ensure training stability and efficiency. We evaluate our method on the HO3D and YCBInEOAT datasets and show that 6DOPE-GS matches the performance of state-of-the-art baselines for model-free simultaneous 6D pose tracking and reconstruction while providing a 5x speedup. We also demonstrate the method's suitability for live, dynamic object tracking and reconstruction in a real-world setting.

Ziqi Gao, Qiufu Li, Linlin Shen

Compared to 2D data, the scale of point cloud data in different domains available for training, is quite limited. Researchers have been trying to combine these data of different domains for masked autoencoder (MAE) pre-training to leverage such a data scarcity issue. However, the prior knowledge learned from mixed domains may not align well with the downstream 3D point cloud analysis tasks, leading to degraded performance. To address such an issue, we propose the Domain-Adaptive Point Cloud Masked Autoencoder (DAP-MAE), an MAE pre-training method, to adaptively integrate the knowledge of cross-domain datasets for general point cloud analysis. In DAP-MAE, we design a heterogeneous domain adapter that utilizes an adaptation mode during pre-training, enabling the model to comprehensively learn information from point clouds across different domains, while employing a fusion mode in the fine-tuning to enhance point cloud features. Meanwhile, DAP-MAE incorporates a domain feature generator to guide the adaptation of point cloud features to various downstream tasks. With only one pre-training, DAP-MAE achieves excellent performance across four different point cloud analysis tasks, reaching 95.18% in object classification on ScanObjectNN and 88.45% in facial expression recognition on Bosphorus. The code will be released at https://github.com/CVI-SZU/DAP-MAE

Zhen Qu, Xian Tao, Xinyi Gong, ShiChen Qu, Xiaopei Zhang, Xingang Wang, Fei Shen, Zhengtao Zhang, Mukesh Prasad, Guiguang Ding

Recent vision-language models (e.g., CLIP) have demonstrated remarkable class-generalizable ability to unseen classes in few-shot anomaly segmentation (FSAS), leveraging supervised prompt learning or fine-tuning on seen classes. However, their cross-category generalization largely depends on prior knowledge of real seen anomaly samples. In this paper, we propose a novel framework, namely DictAS, which enables a unified model to detect visual anomalies in unseen object categories without any retraining on the target data, only employing a few normal reference images as visual prompts. The insight behind DictAS is to transfer dictionary lookup capabilities to the FSAS task for unseen classes via self-supervised learning, instead of merely memorizing the normal and abnormal feature patterns from the training set. Specifically, DictAS mainly consists of three components: (1) **Dictionary Construction** - to simulate the index and content of a real dictionary using features from normal reference images. (2) **Dictionary Lookup** - to retrieve queried region features from the dictionary via a sparse lookup strategy. When a query feature cannot be retrieved, it is classified as an anomaly. (3) **Query Discrimination Regularization**- to enhance anomaly discrimination by making abnormal features harder to retrieve from the dictionary. To achieve this, Contrastive Query Constraint and Text Alignment Constraint are further proposed. Extensive experiments on seven public industrial and medical datasets demonstrate that DictAS consistently outperforms state-of-the-art FSAS methods.

Zheng Gao, Jifei Song, Zhensong Zhang, Jiankang Deng, Ioannis Patras

Current training-free text-driven image translation primarily uses diffusion features (convolution and attention) of pre-trained model as guidance to preserve the style/structure of source image in translated image. However, the coarse guidance at feature level struggles with style (e.g., visual patterns) and structure (e.g., edges) alignment with the source. Based on the observation that the low-/high-frequency components retain style/structure information of image, in this work, we propose training-free Frequency-Guided Diffusion (FGD), which tailors low-/high-frequency guidance for style- and structure-guided translation, respectively. For low-frequency guidance (style-guided), we substitute the low-frequency components of diffusion latents from sampling process with those from inversion of source and normalize the obtained latent with composited spectrum to enforce color alignment. For high-frequency guidance (structure-guided), we propose high-frequency alignment and high-frequency injection that compensate each other. High-frequency alignment preserves edges and contour by adjusting the predicted noise with guidance function that aligns high-frequency image regions between sampling and source image. High-frequency injection facilitates layout preservation by injecting high-frequency components of diffusion convolution features (from inversion) to sampling process. Qualitative and quantitative results verify the superiority of our method on style- and structure-guided translation tasks.

Takehiko Ohkawa, Jihyun Lee, Shunsuke Saito, Jason Saragih, Fabian Prada, Yichen Xu, Shoou-I Yu, Ryosuke Furuta, Yoichi Sato, Takaaki Shiratori

One can hardly model self-contact of human poses without considering underlying body shapes. For example, the pose of rubbing a belly for a person with a low BMI leads to penetration of the hand into the belly for a person with a high BMI. Despite its relevance, existing self-contact datasets lack the variety of self-contact poses and precise body shapes, limiting conclusive analysis between self-contact poses and shapes. To address this, we begin by introducing the first extensive self-contact dataset with precise body shape registration, Goliath-SC, consisting of 383K self-contact poses across 130 subjects. Using this dataset, we propose generative modeling of self-contact prior conditioned by body shape parameters, based on a body-part-wise latent diffusion with self-attention. We further incorporate this prior into single-view human pose estimation while refining estimated poses to be in contact. Our experiments suggest that shape conditioning is vital to the successful modeling of self-contact pose distribution, hence improving single-view pose estimation in self-contact.

Jaeseok Jeong, Junho Kim, Gayoung Lee, Yunjey Choi, Youngjung Uh

In the domain of text-to-image generation, diffusion models have emerged as powerful tools. Recently, studies on visual prompting, where images are used as prompts, have enabled more precise control over style and content. However, existing methods often suffer from content leakage, where undesired elements of the visual style prompt are transferred along with the intended style. To address this issue, we 1) extend classifier-free guidance (CFG) to utilize swapping self-attention and propose 2) negative visual query guidance (NVQG) to reduce the transfer of unwanted contents. NVQG employs negative score by intentionally simulating content leakage scenarios that swap queries instead of key and values of self-attention layers from visual style prompts. This simple yet effective method significantly reduces content leakage. Furthermore, we provide careful solutions for using a real image as visual style prompts.Through extensive evaluation across various styles and text prompts, our method demonstrates superiority over existing approaches, reflecting the style of the references, and ensuring that resulting images match the text prompts.

Melanie Götz, Torsten Krauß, Alexandra Dmitrienko

Federated Learning (FL) enables collaborative machine learning across decentralized clients without sharing raw data, which offers enhanced privacy and improved performance. However, FL is vulnerable to poisoning attacks, compromising model integrity through both untargeted performance degradation and targeted backdoor attacks. Detecting backdoors in FL is challenging due to their stealthy nature and variability in local datasets. Existing defenses struggle against adaptive adversaries and distinguishing between poisoning and genuine dataset anomalies. This paper introduces the Siamese Backdoor Inspector (Sibai), a novel meta-classifier-based poisoning defense for FL. Leveraging the staple few-shot learning technique of Siamese networks, Sibai effectively detects malicious contributions in various scenarios, including settings with strong variations between clients' datasets and encounters with adaptive adversaries. Sibai achieves high detection rates, prevents backdoors, minimizes performance impact, and outperforms eight recent defenses regarding F1 score, poisoning prevention, and consistency across complex scenarios.

Yong Liu, Song-Li Wu, Sule Bai, Jiahao Wang, Yitong Wang, Yansong Tang

Open-vocabulary segmentation aims to achieve segmentation of arbitrary categories given unlimited text inputs as guidance. To achieve this, recent works have focused on developing various technical routes to exploit the potential of large-scale pre-trained vision-language models and have made significant progress on existing benchmarks. However, we find that existing test sets are limited in measuring the models' comprehension of "open-vocabulary" concepts, as their semantic space closely resembles the training space, even with many overlapping categories. To this end, we present a new benchmark named OpenBench that differs significantly from the training semantics. It is designed to better assess the model's ability to understand and segment a wide range of real-world concepts. When testing existing methods on OpenBench, we find that their performance diverges from the conclusions drawn on existing test sets. In addition, we propose a method named OVSNet to improve the segmentation performance for diverse and open scenarios. Through elaborate fusion of heterogeneous features and cost-free expansion of the training space, OVSNet achieves state-of-the-art results on both existing datasets and our proposed OpenBench. Corresponding analysis demonstrate the soundness and effectiveness of our proposed benchmark and method.

Han Yu, Kehan Li, Dongbai Li, Yue He, Xingxuan Zhang, Peng Cui

Recently, there has been gradually more attention paid to Out-of-Distribution (OOD) performance prediction, whose goal is to predict the performance of trained models on unlabeled OOD test datasets, so that we could better leverage and deploy off-the-shelf trained models in risk-sensitive scenarios. Although progress has been made in this area, evaluation protocols in previous literature are inconsistent, and most works cover only a limited number of real-world OOD datasets and types of distribution shifts. To provide convenient and fair comparisons for various algorithms, we propose Out-of-Distribution Performance Prediction Benchmark (ODP-Bench), a comprehensive benchmark that includes most commonly used OOD datasets and existing practical performance prediction algorithms. We provide our trained models as a testbench for future researchers, thus guaranteeing the consistency of comparison and avoiding the burden of repeating the model training process. Furthermore, we also conduct in-depth experimental analyses to better understand their capability boundary.

Yuan Liang, Yang Zhou, Ziming Sun, Tianyi Xiang, Guiqing Li, Shengfeng He

Depth estimation in dynamic, multi-object scenes remains a major challenge, especially under severe occlusions. Existing monocular models, including foundation models, struggle with instance-wise depth consistency due to their reliance on global regression. We tackle this problem from two key aspects: data and methodology. First, we introduce the Group Instance Depth (GID) dataset, the first large-scale video depth dataset with instance-level annotations, featuring 101,500 frames from real-world activity scenes. GID bridges the gap between synthetic and real-world depth data by providing high-fidelity depth supervision for multi-object interactions. Second, we propose InstanceDepth, the first occlusion-aware depth estimation framework for multi-object environments. Our two-stage pipeline consists of (1) Holistic Depth Initialization, which assigns a coarse scene-level depth structure, and (2) Instance-Aware Depth Rectification, which refines instance-wise depth using object masks, shape priors, and spatial relationships. By enforcing geometric consistency across occlusions, our method sets a new state-of-the-art on the GID dataset and multiple benchmarks.

Qiucheng Wu, Handong Zhao, Michael Saxon, Trung Bui, William Yang Wang, Yang Zhang, Shiyu Chang

Multimodal large language models are an exciting emerging class of language models (LMs) that have merged classic LM capabilities with those of image processing systems. However, how these capabilities integrate is often not intuitive and warrants direct investigation. One understudied capability in MLLMs is visual spatial planning---the ability to comprehend the spatial arrangements of objects and devise action plans to achieve desired outcomes in visual scenes. It is unclear why MLLMs fall short on these tasks generally considered easy for humans, given their successes across other diverse scenarios. To this end, we introduce VSP, a benchmark that 1) evaluates the spatial planning capability in MLLMs in general, and 2) diagnoses this capability via finer-grained sub-tasks, including perception and reasoning, and measure the capabilities of models through these sub-tasks. Our evaluation confirms that both open-source and private MLLMs fail to generate effective plans for even simple spatial planning tasks. Evaluations on the fine-grained analytical tasks further reveal fundamental deficiencies in the models' visual perception and bottlenecks in reasoning abilities, explaining their worse performance in the general spatial planning tasks. Our work illuminates future directions for improving MLLMs' abilities in spatial planning. Our benchmark is publicly available.

Seungju Yoo, Hyuk Kwon, Joong-Won Hwang, Kibok Lee

Recent advances in computer vision have made training object detectors more efficient and effective; however, assessing their performance in real-world applications still relies on costly manual annotation. To address this limitation, we develop an automated model evaluation (AutoEval) framework for object detection. We propose Prediction Consistency and Reliability (PCR), which leverages the multiple candidate bounding boxes that conventional detectors generate before non-maximum suppression (NMS). PCR estimates detection performance without ground-truth labels by jointly measuring 1) the spatial consistency between boxes before and after NMS, and 2) the reliability of the retained boxes via the confidence scores of overlapping boxes. For a more realistic and scalable evaluation, we construct a meta-dataset by applying image corruptions of varying severity. Experimental results demonstrate that PCR yields more accurate performance estimates than existing AutoEval methods, and the proposed meta-dataset covers a wider range of detection performance. The code is available at https://github.com/YonseiML/autoeval-det.

Aritra Bhowmik, Mohammad Mahdi Derakhshani, Dennis Koelma, Yuki M. Asano, Martin R. Oswald, Cees G. M. Snoek

Spatial awareness is key to enable embodied multimodal AI systems. Yet, without vast amounts of spatial supervision, current Multimodal Large Language Models (MLLMs) struggle at this task. In this paper, we introduce TWIST & SCOUT, a framework that equips pre-trained MLLMs with visual grounding ability without forgetting their existing image and language understanding skills. To this end, we propose TWIST, a twin-expert stepwise tuning module that modifies the decoder of the language model using one frozen module pre-trained on image understanding tasks and another learnable one for visual grounding tasks. This allows the MLLM to retain previously learned knowledge and skills, while acquiring what is missing. To fine-tune the model effectively, we generate a high-quality synthetic dataset we call SCOUT, which mimics human reasoning in visual grounding. This dataset provides rich supervision signals, describing a step-by-step multimodal reasoning process, thereby simplifying the task of visual grounding. We evaluate our approach on several standard benchmark datasets, encompassing grounded image captioning, zero-shot localization, and visual grounding tasks. Our method consistently delivers strong performance across all tasks, while retaining the pre-trained image understanding capabilities.

Youming Deng, Wenqi Xian, Guandao Yang, Leonidas Guibas, Gordon Wetzstein, Steve Marschner, Paul Debevec

Large field-of-view (FOV) cameras can simplify and accelerate scene capture because they provide complete coverage with fewer views. However, existing reconstruction pipelines fail to take full advantage of large-FOV input data because they convert input views to perspective images, resulting in stretching that prevents the use of the full image. Additionally, they calibrate lenses using models that do not accurately fit real fisheye lenses in the periphery. We present a new reconstruction pipeline based on Gaussian Splatting that uses a flexible lens model and supports fields of view approaching 180 degrees. We represent lens distortion with a hybrid neural field based on an Invertible ResNet and use a cubemap to render wide-FOV images while retaining the efficiency of the Gaussian Splatting pipeline. Our system jointly optimizes lens distortion, camera intrinsics, camera poses, and scene representations using a loss measured directly against the original input pixels. We present extensive experiments on both synthetic and real-world scenes, demonstrating that our model accurately fits real-world fisheye lenses and that our end-to-end self-calibration approach provides higher-quality reconstructions than existing methods. More details and videos can be found at the project page: https://denghilbert.github.io/self-cali/.