We propose a novel training-free image generation algorithm that precisely controls the occlusion relationships between objects in an image. Existing image generation methods typically rely on prompts to influence occlusion, which often lack precision. While layout-to-image methods provide control over object locations, they fail to address occlusion relationships explicitly. Given a pre-trained image diffusion model, our method leverages volume rendering principles to "render" the scene in latent space, guided by occlusion relationships and the estimated transmittance of objects. This approach does not require retraining or fine-tuning the image diffusion model, yet it enables accurate occlusion control due to its physics-grounded foundation. In extensive experiments, our method significantly outperforms existing approaches in terms of occlusion accuracy. Furthermore, we demonstrate that by adjusting the opacities of objects or concepts during rendering, our method can achieve a variety of effects, such as altering the transparency of objects, the density of mass (e.g., forests), the concentration of particles (e.g., rain, fog), the intensity of light, and the strength of lens effects, etc.
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Sculpting Memory: Multi-Concept Forgetting in Diffusion Models via Dynamic Mask and Concept-Aware Optimization
PDF ↗Text-to-image (T2I) diffusion models have achieved remarkable success in generating high-quality images from textual prompts. However, their ability to store vast amounts of knowledge raises concerns in scenarios where selective forgetting is necessary, such as removing copyrighted content, reducing biases, or eliminating harmful concepts. While existing unlearning methods can remove certain concepts, they struggle with multi-concept forgetting due to instability, residual knowledge persistence, and generation quality degradation. To address these challenges, we propose **Dynamic Mask coupled with Concept-Aware Loss**, a novel unlearning framework designed for multi-concept forgetting in diffusion models. Our **Dynamic Mask** mechanism adaptively updates gradient masks based on current optimization states, allowing selective weight modifications that prevent interference with unrelated knowledge. Additionally, our **Concept-Aware Loss** explicitly guides the unlearning process by enforcing semantic consistency through superclass alignment, while a regularization loss based on knowledge distillation ensures that previously unlearned concepts remain forgotten during sequential unlearning. We conduct extensive experiments to evaluate our approach. Results demonstrate that our method outperforms existing unlearning techniques in forgetting effectiveness, output fidelity, and semantic coherence, particularly in multi-concept scenarios. Our work provides a principled and flexible framework for stable and high-fidelity unlearning in generative models. Code available in https://github.com/coulsonlee/Sculpting-Memory-ICCV-2025
We present SuperDec, an approach for compact 3D scene representations based on geometric primitives, namely superquadrics.While most recent works leverage geometric primitives to obtain photorealistic 3D scene representations, we propose to leverage them to obtain a compact yet expressive representation. We propose to solve the problem locally on individual objects and leverage the capabilities of instance segmentation methods to scale our solution to full 3D scenes. In doing that, we design a new architecture which efficiently decompose point clouds of arbitrary objects in a compact set of superquadrics. We train our architecture on ShapeNet and we prove its generalization capabilities on object instances extracted from the ScanNet++ dataset as well as on full Replica scenes. Finally, we show how a compact representation based on superquadrics can be useful for a diverse range of downstream applications, including robotic tasks and controllable visual content generation and editing.
Monocular 3D object detectors, while effective on data from one ego camera height, struggle with unseen or out-of-distribution camera heights. Existing methods often rely on Plucker embeddings, image transformations or data augmentation. This paper takes a step towards this understudied problem by investigating the impact of camera height variations on state-of-the-art (SoTA) Mono3D models. With a systematic analysis on the extended CARLA dataset with multiple camera heights, we observe that depth estimation is a primary factor influencing performance under height variations. We mathematically prove and also empirically observe consistent negative and positive trends in mean depth error of regressed and ground-based depth models, respectively, under camera height changes. To mitigate this, we propose Camera Height Robust Monocular 3D Detector (CHARM3R), which averages both depth estimates within the model. CHARM3R significantly improves generalization to unseen camera heights, by more than 45%, achieving SoTA performance on the CARLA dataset.
In this work, we propose Visual-Predictive Instruction Tuning (VPiT) - a simple and effective extension to visual instruction tuning that enables a pretrained LLM to quickly morph into an unified autoregressive model capable of generating both text and visual tokens. VPiT teaches an LLM to predict discrete text tokens and continuous visual tokens from any input sequence of image and text data curated in an instruction-following format. Our empirical investigation reveals several intriguing properties of VPiT: (1) visual generation ability emerges as a natural byproduct of improved visual understanding, and can be unlocked efficiently with a small amount of generation data; (2) while we find understanding and generation to be mutually beneficial, understanding data contributes to both capabilities more effectively than generation data. Building upon these findings, we train our MetaMorph model and achieve competitive performance on both visual understanding and generation. In visual generation, MetaMorph can leverage the world knowledge and reasoning abilities gained from LLM pretraining, and overcome common failure modes exhibited by other generation models. Our results suggest that LLMs may have strong "prior" vision capabilities that can be efficiently adapted to both visual understanding and generation with a relatively simple instruction tuning process.
RGBA images, with the additional alpha channel, are crucial for any application that needs blending, masking, or transparency effects, making them more versatile than standard RGB images. Nevertheless, existing image inpainting methods are designed exclusively for RGB images. Conventional approaches to transparent image inpainting typically involve placing a background underneath RGBA images and employing a two-stage process: image inpainting followed by image matting. This pipeline, however, struggles to preserve transparency consistency in edited regions, and matting can introduce jagged edges along transparency boundaries. To address these challenges, we propose Trans-Adapter, a plug-and-play adapter that enables diffusion-based inpainting models to process transparent images directly. Trans-Adapter also supports controllable editing via ControlNet and can be seamlessly integrated into various community models. To evaluate our method, we introduce LayerBench, along with a novel non-reference alpha edge quality evaluation metric for assessing transparency edge quality. We conduct extensive experiments on LayerBench to demonstrate the effectiveness of our approach.
Borrowing Eyes for the Blind Spot: Overcoming Data Scarcity in Malicious Video Detection via Cross-Domain Retrieval Augmentation
PDF ↗The rapid proliferation of online video-sharing platforms has accelerated the spread of malicious videos, creating an urgent need for robust detection methods. However, the performance and generalizability of existing detection approaches are severely limited by the scarcity of annotated video data, as manually curating large-scale malicious detection datasets is both labor-intensive and impractical. To address this challenge, we propose CRAVE, a novel CRoss-domAin retrieVal augmEntation framework that transfers knowledge from resource-rich image-text domain to enhance malicious video detection. Specifically, CRAVE introduces a Pseudo-Pair Retriever to identify semantically relevant image-text data for high-quality cross-domain augmentation. Additionally, a Contrastive Cross-Domain Augmenter is designed to disentangle domain-shared and -unique representations, effectively bridging the domain gaps during knowledge transfer. These shared image-text representations are then leveraged to refine video representations, yielding more discriminative features for accurate malicious content detection. Experiments on four video datasets demonstrate that CRAVE largely outperforms competitive baselines in both performance and generalization, providing an innovative and strong solution to the issue of video data-scarcity.
Is visual information alone sufficient for visual speech recognition (VSR) in challenging real-world scenarios? Humans do not rely solely on visual information for lip-reading but also incorporate additional cues, such as speech-related context and prior knowledge about the task. However, existing methods have largely overlooked such external information in automatic VSR systems. To systematically explore the role of such information for VSR, we introduce the concept of Peripheral Information. We categorize it into three types based on the relevance to the spoken content: (1) Contextual Guidance (e.g., topic or description of speech), (2) Task Expertise (e.g., human prior experience in lip-reading), and (3) Linguistic Perturbation (irrelevant signals processed alongside meaningful information). Considering the disparity that peripheral information provides additional clues with varying significance while visual input serves as the most direct source for VSR, we propose a framework that introduces a hierarchical processing strategy to handle different modalities. With visual-specific adaptation and a dynamic routing mechanism for multi-modal information, our approach reduces the impact of modality conflicts effectively and enables selective utilization of peripheral information with varying relevance. Leveraging readily available peripheral information, our model achieves a WER of 22.03% on LRS3. Further experiments on AVSpeech demonstrate its generalization in real-world scenarios.
MosaicDiff: Training-free Structural Pruning for Diffusion Model Acceleration Reflecting Pretraining Dynamics
PDF ↗Diffusion models are renowned for their generative capabilities, yet their pretraining processes exhibit distinct phases of learning speed that have been entirely overlooked in prior post-training acceleration efforts in the community. In this study, we introduce a novel framework called ***MosaicDiff*** that aligns diffusion pretraining dynamics with post-training sampling acceleration via trajectory-aware structural pruning. Our approach leverages the observation that the middle, fast-learning stage of diffusion pretraining requires more conservative pruning to preserve critical model features, while the early and later, slow-learning stages benefit from a more aggressive pruning strategy. This adaptive pruning mechanism is the first to explicitly mirror the inherent learning speed variations of diffusion pretraining, thereby harmonizing the model's inner training dynamics with its accelerated sampling process. Extensive experiments on DiT and SDXL demonstrate that our method achieves significant speed-ups in sampling without compromising output quality, outperforming previous state-of-the-art methods by large margins, also providing a new viewpoint for more efficient and robust training-free diffusion acceleration.
Vector Quantization (VQ) is essential for discretizing continuous representations in unsupervised learning but suffers from representation collapse, causing low codebook utilization and limiting scalability. Existing solutions often rely on complex optimizations or reduce latent dimensionality, which compromises model capacity and fails to fully solve the problem. We identify the root cause as disjoint codebook optimization, where only a few code vectors are updated via gradient descent. To fix this, we propose SimpleVQ, which reparameterizes code vectors through a learnable linear transformation layer over a latent basis, optimizing the entire linear space rather than nearest individual code vectors. Although the multiplication of two linear matrices is equivalent to applying a single linear layer, this simple approach effectively prevents collapse. Extensive experiments on image and audio tasks demonstrate that SimVQ improves codebook usage, is easy to implement, and generalizes well across modalities and architectures.
In MLLMs, Visual perception refers to the process by which MLLMs encode visual inputs, such as images, and align them with the text embedding space. Currently, MLLMs still lack the capability to autonomously control their own visual perception processes. For example, they cannot selectively re-encode specific regions of an image or focus on information related to specific object categories. In this work, we propose the concept of Visual Perception Token, aiming to empower MLLM with a mechanism to control its visual perception processes. We design two types of Visual Perception Tokens, termed the Region Selection Token and the Vision Re-Encoding Token. MLLMs autonomously generate these tokens, just as they generate natural language tokens, and use them to trigger additional visual perception process. The Region Selection Token explicitly identifies regions of interest that require further processing, while the Vision Re-Encoding Token utilizes its hidden states to guide an additional vision encoding process. Extensive experiments highlight the effectiveness of these tokens in enhancing spatial reasoning, fine-grained understanding, Text/OCR-related VQA, and a wide range of other visual tasks. On average, the introduction of Visual Perception Tokens improves the performance of a 2B model by 30.9%, increasing its score from 0.572 to 0.749, and even outperforms a 7B parameter model by 20.0% (from 0.624).
AM-Adapter: Appearance Matching Adapter for Exemplar-based Semantic Image Synthesis in-the-Wild
PDF ↗Exemplar-based semantic image synthesis generates images aligned with semantic content while preserving the appearance of an exemplar. Conventional structure-guidance models like ControlNet, are limited as they rely solely on text prompts to control appearance and cannot utilize exemplar images as input. Recent tuning-free approaches address this by transferring local appearance via implicit cross-image matching in the augmented self-attention mechanism of pre-trained diffusion models. However, prior works are often restricted to single-object cases or foreground object appearance transfer, struggling with complex scenes involving multiple objects. To overcome this, we propose AM-Adapter (Appearance Matching Adapter) to address exemplar-based semantic image synthesis in-the-wild, enabling multi-object appearance transfer from a single scene-level image. AM-Adapter automatically transfers local appearances from the scene-level input. AM-Adapter alternatively provides controllability to map user-defined object details to specific locations in the synthesized images. Our learnable framework enhances cross-image matching within augmented self-attention by integrating semantic information from segmentation maps. To disentangle generation and matching, we adopt stage-wise training. We first train the structure-guidance and generation networks, followed by training the matching adapter while keeping the others frozen. During inference, we introduce an automated exemplar retrieval method for selecting exemplar image-segmentation pairs efficiently. Despite utilizing minimal learnable parameters, AM-Adapter achieves state-of-the-art performance, excelling in both semantic alignment and local appearance fidelity. Extensive ablations validate our design choices. Code and weights will be released.
TryOn-Refiner: Conditional Rectified-flow-based TryOn Refiner for More Accurate Detail Reconstruction
PDF ↗Diffusion techniques has significantly advanced the development of virtual try-on. However, these methods often struggle to preserve intricate details, such as patterns, texts and faces, etc. To tackle this challenge, we introduce a plug-and-play module named as "TryOn-Refiner", which can refine the detailed artifacts for any try-on results in only 1~10 steps.Instead of the previous diffusion-based refine module, TryOn-Refiner employs the conditional rectified-flow-based mechanism for better leveraging prior information from coarse try-on results. Specifically, TryOn-Refiner transforms the traditional refinement framework from a noise-to-image paradigm into a flow mapping framework that directly maps coarse images to refined images, essentially avoiding introducing uncertainty in the refinement process.Moreover, we propose a training data construction pipeline, which can efficiently generate paired training data and includes a data smoothing strategy to overcome the blocking artifact.Extended experimental results demonstrate our TryOn-Refiner consistently improves performance with only a few inference steps for all evaluated existing try-on methods.
Point cloud interpolation aims to recover intermediate frames for temporally smoothing a point cloud sequence. However, real-world challenges, such as uneven or large scene motions, cause existing methods to struggle with limited interpolation precision. To address this, we introduce DiffPCI, a novel diffusion interpolation model that formulates the frame interpolation task as a progressive denoising diffusion process. Training DiffPCI involves two key stages: a forward interpolation diffusion process and a reverse interpolation denoising process. In the forward process, the clean intermediate frame is progressively transformed into a noisy one through continuous Gaussian noise injection. The reverse process then focuses on training a denoiser to gradually refine this noisy frame back to the ground-truth frame. In particular, we derive a point cloud interpolation-specific variational lower bound as our optimization objective for denoiser training. Furthermore, to alleviate the interpolation error especially in highly dynamic scenes, we develop a novel full-scale, dual-branch denoiser that enables more comprehensive front-back frame information fusion for robust bi-directional interpolation. Extensive experiments demonstrate that DiffPCI significantly outperforms current state-of-the-art frame interpolation methods (e.g. 27% and 860% reduction in the Chamfer Distance and Earth Mover's Distance on Nuscenes).
3D scene understanding is a long-standing challenge in computer vision and a key component in enabling mixed reality, wearable computing, and embodied AI. Providing a solution to these applications requires a multifaceted approach that covers scene-centric, object-centric, as well as interaction-centric capabilities. While there exist numerous datasets approaching the former two problems, the task of understanding interactable and articulated objects is underrepresented and only partly covered in the research field. In this work, we address this shortcoming by introducing: (1) Articulate3D, an expertly curated 3D dataset featuring high-quality manual annotations on 280 indoor scenes. Articulate3D provides 8 types of annotations for articulated objects, covering parts and detailed motion information,all stored in a standardized scene representation format designed for scalable 3D content creation, exchange and seamless integration into simulation environments. (2) USDNet, a novel unified framework capable of simultaneously predicting part segmentation along with a full specification of motion attributes for articulated objects. We evaluate USDNet on Articulate3D as well as two existing datasets, demonstrating the advantage of our unified dense prediction approach. Furthermore, we highlight the value of Articulate3D through cross-dataset and cross-domain evaluations and showcase its applicability in downstream tasks such as scene editing through LLM prompting and robotic policy training for articulated object manipulation. We provide open access to our dataset, benchmark, and method's source code.
For Few-Shot Class-Incremental Learning (FSCIL), direct fine-tuning causes significant parameter shifts, resulting in catastrophic forgetting and increased resource consumption. While, freezing the pre-trained backbone exacerbates the inconsistency between the backbone and the evolving classifier. To overcome these challenges, we introduce a method called Low-Rank updates after knowledge localization (Lark). In the knowledge localization phase, the Fisher Information Matrix is calculated to measure the sensitivity of parameters in different layers to previously acquired knowledge. This phase ultimately identifies the parameters within the model that are most suitable for learning new knowledge. In the subsequent incremental editing phase, a low-rank incremental update strategy is applied. This strategy ensures that the model parameter updates adhere to a Rank-One matrix structure. By doing so, it minimizes alterations to the original parameters, thereby enabling the model to integrate new knowledge while retaining as much of the previous knowledge as possible. Extensive experimental results demonstrate that the Lark method achieves significant performance improvements on the CIFAR100, mini-ImageNet, and CUB200 datasets, surpassing current state-of-the-art methods.
CleanPose: Category-Level Object Pose Estimation via Causal Learning and Knowledge Distillation
PDF ↗In the effort to achieve robust and generalizable category-level object pose estimation, recent methods primarily focus on learning fundamental representations from data. However, the inherent biases within the data are often overlooked: the repeated training samples and similar environments may mislead the models to over-rely on specific patterns, hindering models' performance on novel instances. In this paper, we present CleanPose, a novel method that mitigates the data biases to enhance category-level pose estimation by integrating causal learning and knowledge distillation. By incorporating key causal variables (structural information and hidden confounders) into causal modeling, we propose the causal inference module based on front-door adjustment, which promotes unbiased estimation by reducing potential spurious correlations. Additionally, to further confront the data bias at the feature level, we devise a residual-based knowledge distillation approach to transfer unbiased semantic knowledge from 3D foundation model, providing comprehensive causal supervision. Extensive experiments across multiple benchmarks (REAL275, CAMERA25 and HouseCat6D) hightlight the superiority of proposed CleanPose over state-of-the-art methods. Code will be available at https://github.com/chrislin0621/CleanPose.
Frequency-Semantic Enhanced Variational Autoencoder for Zero-Shot Skeleton-based Action Recognition
PDF ↗Zero-shot skeleton-based action recognition aims to develop models capable of identifying actions beyond the categories encountered during training. Previous approaches have primarily focused on aligning visual and semantic representations but often overlooked the importance of fine-grained action patterns in the semantic space (e.g., the hand movements in drinking water and brushing teeth). To address these limitations, we propose a Frequency-Semantic Enhanced Variational Autoencoder (FS-VAE) to explore the skeleton semantic representation learning with frequency decomposition. FS-VAE consists of three key components: 1) a frequency-based enhancement module with high- and low-frequency adjustments to enrich the skeletal semantics learning and improve the robustness of zero-shot action recognition; 2) a semantic-based action description with multilevel alignment to capture both local details and global correspondence, effectively bridging the semantic gap and compensating for the inherent loss of information in skeleton sequences; 3) a calibrated cross-alignment loss that enables valid skeleton-text pairs to counterbalance ambiguous ones, mitigating discrepancies and ambiguities in skeleton and text features, thereby ensuring robust alignment. Evaluations on the benchmarks demonstrate the effectiveness of our approach, validating that frequency-enhanced semantic features enable robust differentiation of visually and semantically similar action clusters, thereby improving zero-shot action recognition.
In this work, we show that we only need a single parameter \omega to effectively control granularity in diffusion-based synthesis. This parameter is incorporated during the denoising steps of the diffusion model's reverse process. This simple approach does not require model retraining or architectural modifications and incurs negligible computational overhead, yet enables precise control over the level of details in the generated outputs. Moreover, spatial masks or denoising schedules with varying \omega values can be applied to achieve region-specific or timestep-specific granularity control. External control signals or reference images can guide the creation of precise \omega masks, allowing targeted granularity adjustments. Despite its simplicity, the method demonstrates impressive performance across various image and video synthesis tasks and is adaptable to advanced diffusion models. The code is available at https://github.com/itsmag11/Omegance.
One Look is Enough: Seamless Patchwise Refinement for Zero-Shot Monocular Depth Estimation on High-Resolution Images
PDF ↗Zero-shot depth estimation (DE) models exhibit strong generalization performance as they are trained on large-scale datasets. However, existing models struggle with high-resolution images due to the discrepancy in image resolutions of training (with smaller resolutions) and inference (for high resolutions). Processing them at full resolution leads to decreased estimation accuracy on depth with tremendous memory consumption, while downsampling to the training resolution results in blurred edges in the estimated depth images. Prevailing high-resolution depth estimation methods adopt a patch-based approach, which introduces depth discontinuity issues when reassembling the estimated depth patches, resulting in test-time inefficiency. Additionally, to obtain fine-grained depth details, these methods rely on synthetic datasets due to the real-world sparse ground truth depth, leading to poor generalizability. To tackle these limitations, we propose Patch Refine Once (PRO), an efficient and generalizable tile-based framework. Our PRO consists of two key components: (i) Grouped Patch Consistency Training that enhances test-time efficiency while mitigating the depth discontinuity problem by jointly processing four overlapping patches and enforcing a consistency loss on their overlapping regions within a single backpropagation step, and (ii) Bias Free Masking that prevents the DE models from overfitting to dataset-specific biases, enabling better generalization to real-world datasets even after training on synthetic data. Zero-shot evaluations on Booster, ETH3D, Middlebury 2014, and NuScenes demonstrate that our PRO can be seamlessly integrated into existing depth estimation models. It preserves the performance of original depth estimation models even under grid-based inference on high-resolution images, exhibiting minimal depth discontinuities along patch boundaries. Moreover, our PRO achieves significantly faster inference speed compared to prior patch-based methods.