Denoising diffusion probabilistic models (DDPMs) employ a sequence of white Gaussian noise samples to generate an image. In analogy with GANs those noise maps could be considered as the latent code associated with the generated image. However this native noise space does not possess a convenient structure and is thus challenging to work with in editing tasks. Here we propose an alternative latent noise space for DDPM that enables a wide range of editing operations via simple means and present an inversion method for extracting these edit-friendly noise maps for any given image (real or synthetically generated). As opposed to the native DDPM noise space the edit-friendly noise maps do not have a standard normal distribution and are not statistically independent across timesteps. However they allow perfect reconstruction of any desired image and simple transformations on them translate into meaningful manipulations of the output image (e.g. shifting color edits). Moreover in text-conditional models fixing those noise maps while changing the text prompt modifies semantics while retaining structure. We illustrate how this property enables text-based editing of real images via the diverse DDPM sampling scheme (in contrast to the popular non-diverse DDIM inversion). We also show how it can be used within existing diffusion-based editing methods to improve their quality and diversity. The code of the method is attached to this submission.
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Tracking by natural language specification (TNL) aims to consistently localize a target in a video sequence given a linguistic description in the initial frame. Existing methodologies perform language-based and template-based matching for target reasoning separately and merge the matching results from two sources which suffer from tracking drift when language and visual templates miss-align with the dynamic target state and ambiguity in the later merging stage. To tackle the issues we propose a joint multi-modal tracking framework with 1) a prompt modulation module to leverage the complementarity between temporal visual templates and language expressions enabling precise and context-aware appearance and linguistic cues and 2) a unified target decoding module to integrate the multi-modal reference cues and executes the integrated queries on the search image to predict the target location in an end-to-end manner directly. This design ensures spatio-temporal consistency by leveraging historical visual information and introduces an integrated solution generating predictions in a single step. Extensive experiments conducted on TNL2K OTB-Lang LaSOT and RefCOCOg validate the efficacy of our proposed approach. The results demonstrate competitive performance against state-of-the-art methods for both tracking and grounding. Code is available at https://github.com/twotwo2/QueryNLT
Recently dataset distillation has paved the way towards efficient machine learning especially for image datasets. However the distillation for videos characterized by an exclusive temporal dimension remains an underexplored domain. In this work we provide the first systematic study of video distillation and introduce a taxonomy to categorize temporal compression. Our investigation reveals that the temporal information is usually not well learned during distillation and the temporal dimension of synthetic data contributes little. The observations motivate our unified framework of disentangling the dynamic and static information in the videos. It first distills the videos into still images as static memory and then compensates the dynamic and motion information with a learnable dynamic memory block. Our method achieves state-of-the-art on video datasets at different scales with notably smaller memory storage budget. Our code is available at https://github.com/yuz1wan/video_distillation.
Shallow-Deep Collaborative Learning for Unsupervised Visible-Infrared Person Re-Identification
PDF ↗Unsupervised visible-infrared person re-identification (US-VI-ReID) centers on learning a cross-modality retrieval model without labels reducing the reliance on expensive cross-modality manual annotation. Previous US-VI-ReID works gravitate toward learning cross-modality information with the deep features extracted from the ultimate layer. Nevertheless interfered by the multiple discrepancies solely relying on deep features is insufficient for accurately learning modality-invariant features resulting in negative optimization. The shallow feature from the shallow layers contains nuanced detail information which is critical for effective cross-modality learning but is disregarded regrettably by the existing methods. To address the above issues we design a Shallow-Deep Collaborative Learning (SDCL) framework based on the transformer with shallow-deep contrastive learning incorporating Collaborative Neighbor Learning (CNL) and Collaborative Ranking Association (CRA) module. Specifically CNL unveils the intrinsic homogeneous and heterogeneous collaboration which are harnessed for neighbor alignment enhancing the robustness in a dynamic manner. Furthermore CRA associates the cross-modality labels with the ranking association between shallow and deep features furnishing valuable supervision for cross-modality learning. Extensive experiments validate the superiority of our method even outperforming certain supervised counterparts.
Multi-task learning has become increasingly popular in the machine learning field but its practicality is hindered by the need for large labeled datasets. Most multi-task learning methods depend on fully labeled datasets wherein each input example is accompanied by ground-truth labels for all target tasks. Unfortunately curating such datasets can be prohibitively expensive and impractical especially for dense prediction tasks which require per-pixel labels for each image. With this in mind we propose Joint-Task Regularization (JTR) an intuitive technique which leverages cross-task relations to simultaneously regularize all tasks in a single joint-task latent space to improve learning when data is not fully labeled for all tasks. JTR stands out from existing approaches in that it regularizes all tasks jointly rather than separately in pairs---therefore it achieves linear complexity relative to the number of tasks while previous methods scale quadratically. To demonstrate the validity of our approach we extensively benchmark our method across a wide variety of partially labeled scenarios based on NYU-v2 Cityscapes and Taskonomy.
Object inpainting is a task that involves adding objects to real images and seamlessly compositing them. With the recent commercialization of products like Stable Diffusion and Generative Fill inserting objects into images by using prompts has achieved impressive visual results. In this paper we propose a prompt suggestion model to simplify the process of prompt input. When the user provides an image and a mask our model predicts suitable prompts based on the partial contextual information in the masked image and the shape and location of the mask. Specifically we introduce a concept-diffusion in the CLIP space that predicts CLIP-text embeddings from a masked image. These diffused embeddings can be directly injected into open-source inpainting models like Stable Diffusion and its variants. Alternatively they can be decoded into natural language for use in other publicly available applications such as Generative Fill. Our prompt suggestion model demonstrates a balanced accuracy and diversity showing its capability to be both contextually aware and creatively adaptive.
This paper aims at achieving fine-grained building attribute segmentation in a cross-view scenario i.e. using satellite and street-view image pairs. The main challenge lies in overcoming the significant perspective differences between street views and satellite views. In this work we introduce SG-BEV a novel approach for satellite-guided BEV fusion for cross-view semantic segmentation. To overcome the limitations of existing cross-view projection methods in capturing the complete building facade features we innovatively incorporate Bird's Eye View (BEV) method to establish a spatially explicit mapping of street-view features. Moreover we fully leverage the advantages of multiple perspectives by introducing a novel satellite-guided reprojection module optimizing the uneven feature distribution issues associated with traditional BEV methods. Our method demonstrates significant improvements on four cross-view datasets collected from multiple cities including New York San Francisco and Boston. On average across these datasets our method achieves an increase in mIOU by 10.13% and 5.21% compared with the state-of-the-art satellite-based and cross-view methods. The code and datasets of this work will be released at https://github.com/sysu-liweijia-lab/SG-BEV.
Hide in Thicket: Generating Imperceptible and Rational Adversarial Perturbations on 3D Point Clouds
PDF ↗Adversarial attack methods based on point manipulation for 3D point cloud classification have revealed the fragility of 3D models yet the adversarial examples they produce are easily perceived or defended against. The trade-off between the imperceptibility and adversarial strength leads most point attack methods to inevitably introduce easily detectable outlier points upon a successful attack. Another promising strategy shape-based attack can effectively eliminate outliers but existing methods often suffer significant reductions in imperceptibility due to irrational deformations. We find that concealing deformation perturbations in areas insensitive to human eyes can achieve a better trade-off between imperceptibility and adversarial strength specifically in parts of the object surface that are complex and exhibit drastic curvature changes. Therefore we propose a novel shape-based adversarial attack method HiT-ADV which initially conducts a two-stage search for attack regions based on saliency and imperceptibility scores and then adds deformation perturbations in each attack region using Gaussian kernel functions. Additionally HiT-ADV is extendable to physical attack. We propose that by employing benign resampling and benign rigid transformations we can further enhance physical adversarial strength with little sacrifice to imperceptibility. Extensive experiments have validated the superiority of our method in terms of adversarial and imperceptible properties in both digital and physical spaces.
Causal-CoG: A Causal-Effect Look at Context Generation for Boosting Multi-modal Language Models
PDF ↗While Multi-modal Language Models (MLMs) demon strate impressive multimodal ability they still struggle on providing factual and precise responses for tasks like vi sual question answering (VQA). In this paper we address this challenge from the perspective of contextual informa tion. We propose Causal Context Generation Causal-CoG which is a prompting strategy that engages contextual infor mation to enhance precise VQA during inference. Specifi cally we prompt MLMs to generate contexts i.e text de scription of an image and engage the generated contexts for question answering. Moreover we investigate the ad vantage of contexts on VQA from a causality perspective introducing causality filtering to select samples for which contextual information is helpful. To show the effective ness of Causal-CoG we run extensive experiments on 10 multimodal benchmarks and showconsistent improvements e.g. +6.30% on POPE +13.69% on Vizwiz and +6.43% on VQAv2 compared to direct decoding surpassing exist ing methods. We hope Casual-CoG inspires explorations of context knowledge in multimodal models and serves as a plug-and-play strategy for MLM decoding.
Face personalization aims to insert specific faces taken from images into pretrained text-to-image diffusion models. However it is still challenging for previous methods to preserve both the identity similarity and editability due to overfitting to training samples. In this paper we propose Face2Diffusion (F2D) for high-editability face personalization. The core idea behind F2D is that removing identity-irrelevant information from the training pipeline prevents the overfitting problem and improves editability of encoded faces. F2D consists of the following three novel components: 1) Multi-scale identity encoder provides well-disentangled identity features while keeping the benefits of multi-scale information which improves the diversity of camera poses. 2) Expression guidance disentangles face expressions from identities and improves the controllability of face expressions. 3) Class-guided denoising regularization encourages models to learn how faces should be denoised which boosts the text-alignment of backgrounds. Extensive experiments on the FaceForensics++ dataset and diverse prompts demonstrate our method greatly improves the trade-off between the identity- and text-fidelity compared to previous state-of-the-art methods. Code is available at https://github.com/mapooon/Face2Diffusion.
Instruction-based image editing holds immense potential for a variety of applications as it enables users to perform any editing operation using a natural language instruction. However current models in this domain often struggle with accurately executing user instructions. We present Emu Edit a multi-task image editing model which sets state-of-the-art results in instruction-based image editing. To develop Emu Edit we train it to multi-task across an unprecedented range of tasks such as region-based editing free-form editing and Computer Vision tasks all of which are formulated as generative tasks. Additionally to enhance Emu Edit's multi-task learning abilities we provide it with learned task embeddings which guide the generation process towards the correct edit type. Both these elements are essential for Emu Edit's outstanding performance. Furthermore we show that Emu Edit can generalize to new tasks such as image inpainting super-resolution and compositions of editing tasks with just a few labeled examples. This capability offers a significant advantage in scenarios where high-quality samples are scarce. Lastly to facilitate a more rigorous and informed assessment of instructable image editing models we release a new challenging and versatile benchmark that includes seven different image editing tasks.
Although 3D shape matching and interpolation are highly interrelated they are often studied separately and applied sequentially to relate different 3D shapes thus resulting in sub-optimal performance. In this work we present a unified framework to predict both point-wise correspondences and shape interpolation between 3D shapes. To this end we combine the deep functional map framework with classical surface deformation models to map shapes in both spectral and spatial domains. On the one hand by incorporating spatial maps our method obtains more accurate and smooth point-wise correspondences compared to previous functional map methods for shape matching. On the other hand by introducing spectral maps our method gets rid of commonly used but computationally expensive geodesic distance constraints that are only valid for near-isometric shape deformations. Furthermore we propose a novel test-time adaptation scheme to capture both pose-dominant and shape-dominant deformations. Using different challenging datasets we demonstrate that our method outperforms previous state-of-the-art methods for both shape matching and interpolation even compared to supervised approaches.
Though diffusion models excel in image generation their step-by-step denoising leads to slow generation speeds. Consistency training addresses this issue with single-step sampling but often produces lower-quality generations and requires high training costs. In this paper we show that optimizing consistency training loss minimizes the Wasserstein distance between target and generated distributions. As timestep increases the upper bound accumulates previous consistency training losses. Therefore larger batch sizes are needed to reduce both current and accumulated losses. We propose Adversarial Consistency Training (ACT) which directly minimizes the Jensen-Shannon (JS) divergence between distributions at each timestep using a discriminator. Theoretically ACT enhances generation quality and convergence. By incorporating a discriminator into the consistency training framework our method achieves improved FID scores on CIFAR10 and ImageNet 64x64 and LSUN Cat 256x256 datasets retains zero-shot image inpainting capabilities and uses less than 1/6 of the original batch size and fewer than 1/2 of the model parameters and training steps compared to the baseline method this leads to a substantial reduction in resource consumption. Our code is available: https://github.com/kong13661/ACT
CN-RMA: Combined Network with Ray Marching Aggregation for 3D Indoor Object Detection from Multi-view Images
PDF ↗This paper introduces CN-RMA a novel approach for 3D indoor object detection from multi-view images. We observe the key challenge as the ambiguity of image and 3D correspondence without explicit geometry to provide occlusion information. To address this issue CN-RMA leverages the synergy of 3D reconstruction networks and 3D object detection networks where the reconstruction network provides a rough Truncated Signed Distance Function (TSDF) and guides image features to vote to 3D space correctly in an end-to-end manner. Specifically we associate weights to sampled points of each ray through ray marching representing the contribution of a pixel in an image to corresponding 3D locations. Such weights are determined by the predicted signed distances so that image features vote only to regions near the reconstructed surface. Our method achieves state-of-the-art performance in 3D object detection from multi-view images as measured by mAP@0.25 and mAP@0.5 on the ScanNet and ARKitScenes datasets. The code and models are released at https://github.com/SerCharles/CN-RMA.
Out-of-distribution (OOD) generalization in the graph domain is challenging due to complex distribution shifts and a lack of environmental contexts. Recent methods attempt to enhance graph OOD generalization by generating flat environments. However such flat environments come with inherent limitations to capture more complex data distributions. Considering the DrugOOD dataset which contains diverse training environments (e.g. scaffold size etc.) flat contexts cannot sufficiently address its high heterogeneity. Thus a new challenge is posed to generate more semantically enriched environments to enhance graph invariant learning for handling distribution shifts. In this paper we propose a novel approach to generate hierarchical semantic environments for each graph. Firstly given an input graph we explicitly extract variant subgraphs from the input graph to generate proxy predictions on local environments. Then stochastic attention mechanisms are employed to re-extract the subgraphs for regenerating global environments in a hierarchical manner. In addition we introduce a new learning objective that guides our model to learn the diversity of environments within the same hierarchy while maintaining consistency across different hierarchies. This approach enables our model to consider the relationships between environments and facilitates robust graph invariant learning. Extensive experiments on real-world graph data have demonstrated the effectiveness of our framework. Particularly in the challenging dataset DrugOOD our method achieves up to 1.29% and 2.83% improvement over the best baselines on IC50 and EC50 prediction tasks respectively.
3D human pose data collected in controlled laboratory settings present challenges for pose estimators that generalize across diverse scenarios. To address this domain generalization is employed. Current methodologies in domain generalization for 3D human pose estimation typically utilize adversarial training to generate synthetic poses for training. Nonetheless these approaches exhibit several limitations. First the lack of prior information about the target domain complicates the application of suitable augmentation through a single pose augmentor affecting generalization on target domains. Moreover adversarial training's discriminator tends to enforce similarity between source and synthesized poses impeding the exploration of out-of-source distributions. Furthermore the pose estimator's optimization is not exposed to domain shifts limiting its overall generalization ability. To address these limitations we propose a novel framework featuring two pose augmentors: the weak and the strong augmentors. Our framework employs differential strategies for generation and discrimination processes facilitating the preservation of knowledge related to source poses and the exploration of out-of-source distributions without prior information about target poses. Besides we leverage meta-optimization to simulate domain shifts in the optimization process of the pose estimator thereby improving its generalization ability. Our proposed approach significantly outperforms existing methods as demonstrated through comprehensive experiments on various benchmark datasets.
We introduce a new system for Multi-Session SLAM which tracks camera motion across multiple disjoint videos under a single global reference. Our approach couples the prediction of optical flow with solver layers to estimate camera pose. The backbone is trained end-to-end using a novel differentiable solver for wide-baseline two-view pose. The full system can connect disjoint sequences perform visual odometry and global optimization. Compared to existing approaches our design is accurate and robust to catastrophic failures.
Generating vivid and emotional 3D co-speech gestures is crucial for virtual avatar animation in human-machine interaction applications. While the existing methods enable generating the gestures to follow a single emotion label they overlook that long gesture sequence modeling with emotion transition is more practical in real scenes. In addition the lack of large-scale available datasets with emotional transition speech and corresponding 3D human gestures also limits the addressing of this task. To fulfill this goal we first incorporate the ChatGPT-4 and an audio inpainting approach to construct the high-fidelity emotion transition human speeches. Considering obtaining the realistic 3D pose annotations corresponding to the dynamically inpainted emotion transition audio is extremely difficult we propose a novel weakly supervised training strategy to encourage authority gesture transitions. Specifically to enhance the coordination of transition gestures w.r.t. different emotional ones we model the temporal association representation between two different emotional gesture sequences as style guidance and infuse it into the transition generation. We further devise an emotion mixture mechanism that provides weak supervision based on a learnable mixed emotion label for transition gestures. Last we present a keyframe sampler to supply effective initial posture cues in long sequences enabling us to generate diverse gestures. Extensive experiments demonstrate that our method outperforms the state-of-the-art models constructed by adapting single emotion-conditioned counterparts on our newly defined emotion transition task and datasets. Our code and dataset will be released on the project page: https://xingqunqi-lab.github.io/Emo-Transition-Gesture/
In deep metric learning for visual recognition the calibration of distance thresholds is crucial for achieving desired model performance in the true positive rates (TPR) or true negative rates (TNR). However calibrating this thresh- old presents challenges in open-world scenarios where the test classes can be entirely disjoint from those encountered during training. We define the problem of finding distance thresholds for a trained embedding model to achieve target performance metrics over unseen open-world test classes as open-world threshold calibration. Existing posthoc threshold calibration methods reliant on inductive inference and requiring a calibration dataset with a similar distance distribution as the test data often prove ineffective in open- world scenarios. To address this we introduce OpenGCN a Graph Neural Network-based transductive threshold calibration method with enhanced adaptability and robustness. OpenGCN learns to predict pairwise connectivity for the unlabeled test instances embedded in a graph to determine its TPR and TNR at various distance thresholds allowing for transductive inference of the distance thresholds which also incorporates test-time information. Extensive experiments across open-world visual recognition benchmarks validate OpenGCN's superiority over existing posthoc calibration methods for open-world threshold calibration.
Leveraging vast training data multimodal large language models (MLLMs) have demonstrated formidable general visual comprehension capabilities and achieved remarkable performance across various tasks. However their performance in visual document understanding still leaves much room for improvement. This discrepancy is primarily attributed to the fact that visual document understanding is a fine-grained prediction task. In natural scenes MLLMs typically use low-resolution images leading to a substantial loss of visual information. Furthermore general-purpose MLLMs do not excel in handling document-oriented instructions. In this paper we propose a High-Resolution Visual Document Assistant (HRVDA) which bridges the gap between MLLMs and visual document understanding. This model employs a content filtering mechanism and an instruction filtering module to separately filter out the content-agnostic visual tokens and instruction-agnostic visual tokens thereby achieving efficient model training and inference for high-resolution images. In addition we construct a document-oriented visual instruction tuning dataset and apply a multi-stage training strategy to enhance the model's document modeling capabilities. Extensive experiments demonstrate that our model achieves state-of-the-art performance across multiple document understanding datasets while maintaining training efficiency and inference speed comparable to low-resolution models.