CVPR 2024 Papers

Recent advancements in neural networks have showcased their remarkable capabilities across various domains. Despite these successes the "black box" problem still remains. To address this we propose a novel framework WWW that offers the 'what' 'where' and 'why' of the neural network decisions in human-understandable terms. Specifically WWW utilizes an adaptive selection for concept discovery employing adaptive cosine similarity and thresholding techniques to effectively explain 'what'. To address the 'where' and 'why' we proposed a novel combination of neuron activation maps (NAMs) with Shapley values generating localized concept maps and heatmaps for individual inputs. Furthermore WWW introduces a method for predicting uncertainty leveraging heatmap similarities to estimate the prediction's reliability. Experimental evaluations of WWW demonstrate superior performance in both quantitative and qualitative metrics outperforming existing methods in interpretability. WWW provides a unified solution for explaining 'what' 'where' and 'why' introducing a method for localized explanations from global interpretations and offering a plug-and-play solution adaptable to various architectures. The code is available at: https://github.com/ailab-kyunghee/WWW

The rapid advancement of generative models facilitating the creation of hyper-realistic images from textual descriptions has concurrently escalated critical societal concerns such as misinformation. Although providing some mitigation traditional fingerprinting mechanisms fall short in attributing responsibility for the malicious use of synthetic images. This paper introduces a novel approach to model fingerprinting that assigns responsibility for the generated images thereby serving as a potential countermeasure to model misuse. Our method modifies generative models based on each user's unique digital fingerprint imprinting a unique identifier onto the resultant content that can be traced back to the user. This approach incorporating fine-tuning into Text-to-Image (T2I) tasks using the Stable Diffusion Model demonstrates near-perfect attribution accuracy with a minimal impact on output quality. Through extensive evaluation we show that our method outperforms baseline methods with an average improvement of 11% in handling image post-processes. Our method presents a promising and novel avenue for accountable model distribution and responsible use. Our code is available in https://github.com/kylemin/WOUAF.

The estimation of 3D human motion from video has progressed rapidly but current methods still have several key limitations. First most methods estimate the human in camera coordinates. Second prior work on estimating humans in global coordinates often assumes a flat ground plane and produces foot sliding. Third the most accurate methods rely on computationally expensive optimization pipelines limiting their use to offline applications. Finally existing video-based methods are surprisingly less accurate than single-frame methods. We address these limitations with WHAM (World-grounded Humans with Accurate Motion) which accurately and efficiently reconstructs 3D human motion in a global coordinate system from video. WHAM learns to lift 2D keypoint sequences to 3D using motion capture data and fuses this with video features integrating motion context and visual information. WHAM exploits camera angular velocity estimated from a SLAM method together with human motion to estimate the body's global trajectory. We combine this with a contact-aware trajectory refinement method that lets WHAM capture human motion in diverse conditions such as climbing stairs. WHAM outperforms all existing 3D human motion recovery methods across multiple in-the-wild benchmarks. Code is available for research purposes at http://wham.is.tue.mpg.de/.

Synthesizing natural human motions that enable a 3D human avatar to walk and reach for arbitrary goals in 3D space remains an unsolved problem with many applications. Existing methods (data-driven or using reinforcement learning) are limited in terms of generalization and motion naturalness. A primary obstacle is the scarcity of training data that combines locomotion with goal reaching. To address this we introduce WANDR a data-driven model that takes an avatar's initial pose and a goal's 3D position and generates natural human motions that place the end effector (wrist) on the goal location. To solve this we introduce novel intention features that drive rich goal-oriented movement. Intention guides the agent to the goal and interactively adapts the generation to novel situations without needing to define sub-goals or the entire motion path. Crucially intention allows training on datasets that have goal-oriented motions as well as those that do not. WANDR is a conditional Variational Auto-Encoder (c-VAE) which we train using the AMASS and CIRCLE datasets. We evaluate our method extensively and demonstrate its ability to generate natural and long-term motions that reach 3D goals and generalize to unseen goal locations. Our models and code are available for research purposes at wandr.is.tue.mpg.de

Current methods for 2D and 3D object understanding struggle with severe occlusions in busy urban environments partly due to the lack of large-scale labeled ground-truth annotations for learning occlusion. In this work we introduce a novel framework for automatically generating a large realistic dataset of dynamic objects under occlusions using freely available time-lapse imagery. By leveraging off-the-shelf 2D (bounding box segmentation keypoint) and 3D (pose shape) predictions as pseudo-groundtruth unoccluded 3D objects are identified automatically and composited into the background in a clip-art style ensuring realistic appearances and physically accurate occlusion configurations. The resulting clip-art image with pseudo-groundtruth enables efficient training of object reconstruction methods that are robust to occlusions. Our method demonstrates significant improvements in both 2D and 3D reconstruction particularly in scenarios with heavily occluded objects like vehicles and people in urban scenes.

Vision-language navigation (VLN) requires an agent to navigate through an 3D environment based on visual observations and natural language instructions. It is clear that the pivotal factor for successful navigation lies in the comprehensive scene understanding. Previous VLN agents employ monocular frameworks to extract 2D features of perspective views directly. Though straightforward they struggle for capturing 3D geometry and semantics leading to a partial and incomplete environment representation. To achieve a comprehensive 3D representation with fine-grained details we introduce a Volumetric Environment Representation (VER) which voxelizes the physical world into structured 3D cells. For each cell VER aggregates multi-view 2D features into such a unified 3D space via 2D-3D sampling. Through coarse-to-fine feature extraction and multi-task learning for VER our agent predicts 3D occupancy 3D room layout and 3D bounding boxes jointly. Based on online collected VERs our agent performs volume state estimation and builds episodic memory for predicting the next step. Experimental results show our environment representations from multi-task learning lead to evident performance gains on VLN. Our model achieves state-of-the-art performance across VLN benchmarks (R2R REVERIE and R4R).

Self-Supervised Learning (SSL) has demonstrated promising results in 3D medical image analysis. However the lack of high-level semantics in pre-training still heavily hinders the performance of downstream tasks. We observe that 3D medical images contain relatively consistent contextual position information i.e. consistent geometric relations between different organs which leads to a potential way for us to learn consistent semantic representations in pre-training. In this paper we propose a simple-yet-effective Volume Contrast (VoCo) framework to leverage the contextual position priors for pre-training. Specifically we first generate a group of base crops from different regions while enforcing feature discrepancy among them where we employ them as class assignments of different regions. Then we randomly crop sub-volumes and predict them belonging to which class (located at which region) by contrasting their similarity to different base crops which can be seen as predicting contextual positions of different sub-volumes. Through this pretext task VoCo implicitly encodes the contextual position priors into model representations without the guidance of annotations enabling us to effectively improve the performance of downstream tasks that require high-level semantics. Extensive experimental results on six downstream tasks demonstrate the superior effectiveness of VoCo. Code will be available at https://github.com/Luffy03/VoCo.

In this work we present Vlogger a generic AI system for generating a minute-level video blog (i.e. vlog) of user descriptions. Different from short videos with a few seconds vlog often contains a complex storyline with diversified scenes which is challenging for most existing video generation approaches. To break through this bottleneck our Vlogger smartly leverages Large Language Model (LLM) as Director and decomposes a long video generation task of vlog into four key stages where we invoke various foundation models to play the critical roles of vlog professionals including (1) Script (2) Actor (3) ShowMaker and (4) Voicer. With such a design of mimicking human beings our Vlogger can generate vlogs through explainable cooperation of top-down planning and bottom-up shooting. More over we introduce a novel video diffusion model ShowMaker which serves as a videographer in our Vlogger for generating the video snippet of each shooting scene. By incorporating Script and Actor attentively as textual and visual prompts it can effectively enhance spatial-temporal coherence in the snippet. Besides we design a concise mixed training paradigm for ShowMaker boosting its capacity for both T2V generation and prediction. Finally the extensive experiments show that our method achieves state-of-the-art performance on zero-shot T2V generation and prediction tasks. More importantly Vlogger can generate over 5-minute vlogs from open-world descriptions without loss of video coherence on script and actor.

Knowledge distillation is an effective method for training small and efficient deep learning models. However the efficacy of a single method can degenerate when transferring to other tasks modalities or even other architectures. To address this limitation we propose a novel constrained feature distillation method. This method is derived from a small set of core principles which results in two emerging components: an orthogonal projection and a task-specific normalisation. Equipped with both of these components our transformer models can outperform all previous methods on ImageNet and reach up to a 4.4% relative improvement over the previous state-of-the-art methods. To further demonstrate the generality of our method we apply it to object detection and image generation whereby we obtain consistent and substantial performance improvements over state-of-the-art. Code and models are publicly available.

Generative Zero-shot learning (ZSL) learns a generator to synthesize visual samples for unseen classes which is an effective way to advance ZSL. However existing generative methods rely on the conditions of Gaussian noise and the predefined semantic prototype which limit the generator only optimized on specific seen classes rather than characterizing each visual instance resulting in poor generalizations (e.g. overfitting to seen classes). To address this issue we propose a novel Visual-Augmented Dynamic Semantic prototype method (termed VADS) to boost the generator to learn accurate semantic-visual mapping by fully exploiting the visual-augmented knowledge into semantic conditions. In detail VADS consists of two modules: (1) Visual-aware Domain Knowledge Learning module (VDKL) learns the local bias and global prior of the visual features (referred to as domain visual knowledge) which replace pure Gaussian noise to provide richer prior noise information; (2) Vision-Oriented Semantic Updation module (VOSU) updates the semantic prototype according to the visual representations of the samples. Ultimately we concatenate their output as a dynamic semantic prototype which serves as the condition of the generator. Extensive experiments demonstrate that our VADS achieves superior CZSL and GZSL performances on three prominent datasets and outperforms other state-of-the-art methods with averaging increases by 6.4% 5.9% and 4.2% on SUN CUB and AWA2 respectively.

The emergence of attention-based transformer models has led to their extensive use in various tasks due to their superior generalization and transfer properties. Recent research has demonstrated that such models when prompted appropriately are excellent for few-shot inference. However such techniques are under-explored for dense prediction tasks like semantic segmentation. In this work we examine the effectiveness of prompting a transformer-decoder with learned visual prompts for the generalized few-shot segmentation (GFSS) task. Our goal is to achieve strong performance not only on novel categories with limited examples but also to retain performance on base categories. We propose an approach to learn visual prompts with limited examples. These learned visual prompts are used to prompt a multiscale transformer decoder to facilitate accurate dense predictions. Additionally we introduce a unidirectional causal attention mechanism between the novel prompts learned with limited examples and the base prompts learned with abundant data. This mechanism enriches the novel prompts without deteriorating the base class performance. Overall this form of prompting helps us achieve state-of-the-art performance for GFSS on two different benchmark datasets: COCO-20^i and Pascal-5^i without the need for test-time optimization (or transduction). Furthermore test-time optimization leveraging unlabelled test data can be used to improve the prompts which we refer to as transductive prompt tuning.

3D Visual Grounding (3DVG) aims at localizing 3D object based on textual descriptions. Conventional supervised methods for 3DVG often necessitate extensive annotations and a predefined vocabulary which can be restrictive. To address this issue we propose a novel visual programming approach for zero-shot open-vocabulary 3DVG leveraging the capabilities of large language models (LLMs). Our approach begins with a unique dialog-based method engaging with LLMs to establish a foundational understanding of zero-shot 3DVG. Building on this we design a visual program that consists of three types of modules i.e. view-independent view-dependent and functional modules. Furthermore we develop an innovative language-object correlation module to extend the scope of existing 3D object detectors into open-vocabulary scenarios. Extensive experiments demonstrate that our zero-shot approach can outperform some supervised baselines marking a significant stride towards effective 3DVG. Code is available at https://curryyuan.github.io/ZSVG3D.

Solving complex visual tasks such as "Who invented the musical instrument on the right?" involves a composition of skills: understanding space recognizing instruments and also retrieving prior knowledge. Recent work shows promise by decomposing such tasks using a large language model (LLM) into an executable program that invokes specialized vision models. However generated programs are error-prone: they omit necessary steps include spurious ones and are unable to recover when the specialized models give incorrect outputs. Moreover they require loading multiple models incurring high latency and computation costs. We propose Visual Program Distillation (VPD) an instruction-tuning framework that produces a vision-language model (VLM) capable of solving complex visual tasks with a single forward pass. VPD distills the reasoning ability of LLMs by using them to sample multiple candidate programs which are then executed and verified to identify the correct one. It translates each correct program into a language description of the reasoning steps which are then distilled into a VLM. Extensive experiments show that VPD improves the VLM's ability to count understand spatial relations and reason compositionally. Our VPD-trained PaLI-X outperforms all prior VLMs achieving state-of-the-art performance across complex vision tasks including MMBench OK-VQA A-OKVQA TallyQA POPE and Hateful Memes. An evaluation with human annotators also confirms that VPD improves model response factuality and consistency. Finally experiments on content moderation demonstrate that VPD is also helpful for adaptation to real-world applications with limited data.

In contrast to extensive studies on general vision pre-training for scalable visual autonomous driving remains seldom explored. Visual autonomous driving applications require features encompassing semantics 3D geometry and temporal information simultaneously for joint perception prediction and planning posing dramatic challenges for pre-training. To resolve this we bring up a new pre-training task termed as visual point cloud forecasting - predicting future point clouds from historical visual input. The key merit of this task captures the synergic learning of semantics 3D structures and temporal dynamics. Hence it shows superiority in various downstream tasks. To cope with this new problem we present ViDAR a general model to pre-train downstream visual encoders. It first extracts historical embeddings by the encoder. These representations are then transformed to 3D geometric space via a novel Latent Rendering operator for future point cloud prediction. Experiments show significant gain in downstream tasks e.g. 3.1% NDS on 3D detection 10% error reduction on motion forecasting and 15% less collision rate on planning.

In film gender studies the concept of "male gaze" refers to the way the characters are portrayed on-screen as objects of desire rather than subjects. In this article we introduce a novel video-interpretation task to detect character objectification in films. The purpose is to reveal and quantify the usage of complex temporal patterns operated in cinema to produce the cognitive perception of objectification. We introduce the ObyGaze12 dataset made of 1914 movie clips densely annotated by experts for objectification concepts identified in film studies and psychology. We evaluate recent vision models show the feasibility of the task and where the challenges remain with concept bottleneck models. Our new dataset and code are made available to the community.

This paper proposes an image-vector dual diffusion model for generative layout design. Distinct from prior efforts that mostly ignore element-level visual information our approach integrates the power of a pre-trained large image diffusion model to guide layout composition in a vector diffusion model by providing enhanced salient region understanding and high-level inter-element relationship reasoning. Our proposed model simultaneously operates in two domains: it generates the overall design appearance in the image domain while optimizing the size and position of each design element in the vector domain. The proposed method achieves the state-of-the-art results on several datasets and enables new layout design applications.

In-context prompting in large language models (LLMs) has become a prevalent approach to improve zero-shot capabilities but this idea is less explored in the vision domain. Existing visual prompting methods focus on referring segmentation to segment the most relevant object falling short of addressing many generic vision tasks like open-set segmentation and detection. In this paper we introduce a universal visual in-context prompting framework for both tasks as shown in Fig.1. In particular we build on top of an encoder-decoder architecture and develop a versatile prompt encoder to support a variety of prompts like strokes boxes and points. We further enhance it to take an arbitrary number of reference image segments as the context. Our extensive explorations show that the proposed visual in-context prompting elicits extraordinary referring and generic segmentation capabilities to refer and detect yielding competitive performance to close-set in-domain datasets and showing promising results on many open-set segmentation datasets. By joint training on COCO and SA-1B DINOv achieves 57.7 PQ on COCO and 23.2 PQ on ADE20K. Code will be available at https://github.com/UX-Decoder/DINOv

Existing automatic captioning methods for visual content face challenges such as lack of detail content hallucination and poor instruction following. In this work we propose VisualFactChecker (VFC) a flexible training-free pipeline that generates high-fidelity and detailed captions for both 2D images and 3D objects. VFC consists of three steps: 1) proposal where image-to-text captioning models propose multiple initial captions; 2) verification where a large language model (LLM) utilizes tools such as object detection and VQA models to fact-check proposed captions; 3) captioning where an LLM generates the final caption by summarizing caption proposals and the fact check verification results. In this step VFC can flexibly generate captions in various styles following complex instructions. We conduct comprehensive captioning evaluations using four metrics: 1) CLIP-Score for image-text similarity; 2) CLIP-Image-Score for measuring the image-image similarity between the original and the reconstructed image generated by a text-to-image model using the caption. 3) human study on Amazon Mechanical Turk; 4) GPT-4V for fine-grained evaluation. Evaluation results show that VFC outperforms state-of-the-art open-sourced captioning methods for 2D images on the COCO dataset and 3D assets on the Objaverse dataset. Our study demonstrates that by combining open-source models into a pipeline we can attain captioning capability comparable to proprietary models such as GPT-4V despite being over 10x smaller in model size.

Composed Image Retrieval (CIR) is a task that retrieves images similar to a query based on a provided textual modification. Current techniques rely on supervised learning for CIR models using labeled triplets of the <reference image text target image>. These specific triplets are not as commonly available as simple image-text pairs limiting the widespread use of CIR and its scalability. On the other hand zero-shot CIR can be relatively easily trained with image-caption pairs without considering the image-to-image relation but this approach tends to yield lower accuracy. We propose a new semi-supervised CIR approach where we search for a reference and its related target images in auxiliary data and learn our large language model-based Visual Delta Generator (VDG) to generate text describing the visual difference (i.e. visual delta) between the two. VDG equipped with fluent language knowledge and being model agnostic can generate pseudo triplets to boost the performance of CIR models. Our approach significantly improves the existing supervised learning approaches and achieves state-of-the-art results on the CIR benchmarks.