mtybilly/Instruct2DS huggingface dataset:
Dynamic LiDAR Re-simulation using Compositional Neural Fields
Authors: Hanfeng Wu, Xingxing Zuo, Stefan Leutenegger, Or Litany, Konrad Schindler, Shengyu Huang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: We introduce DyNFL a novel neural field-based approach for high-fidelity re-simulation of LiDAR scans in dynamic driving scenes. DyNFL processes LiDAR measurements from dynamic environments accompanied by bounding boxes of moving objects to construct an editable neural field. This field comprising separately reconstructed static background and dynamic objects allows users to modify viewpoints adjust object positions and seamlessly add or remove objects in the re-simulated scene. A key innovation of our method is the neural field composition technique which effectively integrates reconstructed neural assets from various scenes through a ray drop test accounting for occlusions and transparent surfaces. Our evaluation with both synthetic and real-world environments demonstrates that DyNFL substantially improves dynamic scene LiDAR simulation offering a combination of physical fidelity and flexible editing capabilities. Project page: https://shengyuh.github.io/dynfl
Explaining CLIP's Performance Disparities on Data from Blind/Low Vision Users
Authors: Daniela Massiceti, Camilla Longden, Agnieszka Slowik, Samuel Wills, Martin Grayson, Cecily Morrison
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Large multi-modal models (LMMs) hold the potential to usher in a new era of automated visual assistance for people who are blind or low vision (BLV). Yet these models have not been systematically evaluated on data captured by BLV users. We address this by empirically assessing CLIP a widely-used LMM likely to underpin many assistive technologies. Testing 25 CLIP variants in a zero-shot classification task we find that their accuracy is 15 percentage points lower on average for images captured by BLV users than web-crawled images. This disparity stems from CLIP's sensitivities to 1) image content (e.g. not recognizing disability objects as well as other objects); 2) image quality (e.g. not being robust to lighting variation); and 3) text content (e.g. not recognizing objects described by tactile adjectives as well as visual ones). We delve deeper with a textual analysis of three common pre-training datasets: LAION-400M LAION-2B and DataComp-1B showing that disability content is rarely mentioned. We then provide three examples that illustrate how the performance disparities extend to three downstream models underpinned by CLIP: OWL-ViT CLIPSeg and DALL-E2. We find that few-shot learning with as few as 5 images can mitigate CLIP's quality-of-service disparities for BLV users in some scenarios which we discuss alongside a set of other possible mitigations.
AETTA: Label-Free Accuracy Estimation for Test-Time Adaptation
Authors: Taeckyung Lee, Sorn Chottananurak, Taesik Gong, Sung-Ju Lee
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Test-time adaptation (TTA) has emerged as a viable solution to adapt pre-trained models to domain shifts using unlabeled test data. However TTA faces challenges of adaptation failures due to its reliance on blind adaptation to unknown test samples in dynamic scenarios. Traditional methods for out-of-distribution performance estimation are limited by unrealistic assumptions in the TTA context such as requiring labeled data or re-training models. To address this issue we propose AETTA a label-free accuracy estimation algorithm for TTA. We propose the prediction disagreement as the accuracy estimate calculated by comparing the target model prediction with dropout inferences. We then improve the prediction disagreement to extend the applicability of AETTA under adaptation failures. Our extensive evaluation with four baselines and six TTA methods demonstrates that AETTA shows an average of 19.8%p more accurate estimation compared with the baselines. We further demonstrate the effectiveness of accuracy estimation with a model recovery case study showcasing the practicality of our model recovery based on accuracy estimation. The source code is available at https://github.com/taeckyung/AETTA.
Digital Life Project: Autonomous 3D Characters with Social Intelligence
Authors: Zhongang Cai, Jianping Jiang, Zhongfei Qing, Xinying Guo, Mingyuan Zhang, Zhengyu Lin, Haiyi Mei, Chen Wei, Ruisi Wang, Wanqi Yin, Liang Pan, Xiangyu Fan, Han Du, Peng Gao, Zhitao Yang, Yang Gao, Jiaqi Li, Tianxiang Ren, Yukun Wei, Xiaogang Wang, Chen Change Loy, Lei Yang, Ziwei Liu
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: In this work we present Digital Life Project a framework utilizing language as the universal medium to build autonomous 3D characters who are capable of engaging in social interactions and expressing with articulated body motions thereby simulating life in a digital environment. Our framework comprises two primary components: 1) SocioMind: a meticulously crafted digital brain that models personalities with systematic few-shot exemplars incorporates a reflection process based on psychology principles and emulates autonomy by initiating dialogue topics; 2) MoMat-MoGen: a text-driven motion synthesis paradigm for controlling the character's digital body. It integrates motion matching a proven industry technique to ensure motion quality with cutting-edge advancements in motion generation for diversity. Extensive experiments demonstrate that each module achieves state-of-the-art performance in its respective domain. Collectively they enable virtual characters to initiate and sustain dialogues autonomously while evolving their socio-psychological states. Concurrently these characters can perform contextually relevant bodily movements. Additionally an extension of DLP enables a virtual character to recognize and appropriately respond to human players' actions.
Unsupervised Universal Image Segmentation
Authors: Dantong Niu, Xudong Wang, Xinyang Han, Long Lian, Roei Herzig, Trevor Darrell
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Several unsupervised image segmentation approaches have been proposed which eliminate the need for dense manually-annotated segmentation masks; current models separately handle either semantic segmentation (e.g. STEGO) or class-agnostic instance segmentation (e.g. CutLER) but not both (i.e. panoptic segmentation). We propose an Unsupervised Universal Segmentation model (U2Seg) adept at performing various image segmentation tasks---instance semantic and panoptic---using a novel unified framework. U2Seg generates pseudo semantic labels for these segmentation tasks via leveraging self-supervised models followed by clustering; each cluster represents different semantic and/or instance membership of pixels. We then self-train the model on these pseudo semantic labels yielding substantial performance gains over specialized methods tailored to each task: a +2.6 APbox boost (vs. CutLER) in unsupervised instance segmentation on COCO and a +7.0 PixelAcc increase (vs. STEGO) in unsupervised semantic segmentation on COCOStuff. Moreover our method sets up a new baseline for unsupervised panoptic segmentation which has not been previously explored. U2Seg is also a strong pretrained model for few-shot segmentation surpassing CutLER by +5.0 APmask when trained on a low-data regime e.g. only 1% COCO labels. We hope our simple yet effective method can inspire more research on unsupervised universal image segmentation.
Rethinking Prior Information Generation with CLIP for Few-Shot Segmentation
Authors: Jin Wang, Bingfeng Zhang, Jian Pang, Honglong Chen, Weifeng Liu
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Few-shot segmentation remains challenging due to the limitations of its labeling information for unseen classes. Most previous approaches rely on extracting high-level feature maps from the frozen visual encoder to compute the pixel-wise similarity as a key prior guidance for the decoder. However such a prior representation suffers from coarse granularity and poor generalization to new classes since these high-level feature maps have obvious category bias. In this work we propose to replace the visual prior representation with the visual-text alignment capacity to capture more reliable guidance and enhance the model generalization. Specifically we design two kinds of training-free prior information generation strategy that attempts to utilize the semantic alignment capability of the Contrastive Language-Image Pre-training model (CLIP) to locate the target class. Besides to acquire more accurate prior guidance we build a high-order relationship of attention maps and utilize it to refine the initial prior information. Experiments on both the PASCAL-5i and COCO-20i datasets show that our method obtains a clearly substantial improvement and reaches the new state-of-the-art performance. The code is available on the project website.
SingularTrajectory: Universal Trajectory Predictor Using Diffusion Model
Authors: Inhwan Bae, Young-Jae Park, Hae-Gon Jeon
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: There are five types of trajectory prediction tasks: deterministic stochastic domain adaptation momentary observation and few-shot. These associated tasks are defined by various factors such as the length of input paths data split and pre-processing methods. Interestingly even though they commonly take sequential coordinates of observations as input and infer future paths in the same coordinates as output designing specialized architectures for each task is still necessary. For the other task generality issues can lead to sub-optimal performances. In this paper we propose SingularTrajectory a diffusion-based universal trajectory prediction framework to reduce the performance gap across the five tasks. The core of SingularTrajectory is to unify a variety of human dynamics representations on the associated tasks. To do this we first build a Singular space to project all types of motion patterns from each task into one embedding space. We next propose an adaptive anchor working in the Singular space. Unlike traditional fixed anchor methods that sometimes yield unacceptable paths our adaptive anchor enables correct anchors which are put into a wrong location based on a traversability map. Finally we adopt a diffusion-based predictor to further enhance the prototype paths using a cascaded denoising process. Our unified framework ensures the generality across various benchmark settings such as input modality and trajectory lengths. Extensive experiments on five public benchmarks demonstrate that SingularTrajectory substantially outperforms existing models highlighting its effectiveness in estimating general dynamics of human movements. Code is publicly available at https://github.com/inhwanbae/SingularTrajectory.
Generating Handwritten Mathematical Expressions From Symbol Graphs: An End-to-End Pipeline
Authors: Yu Chen, Fei Gao, Yanguang Zhang, Maoying Qiao, Nannan Wang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: In this paper we explore a novel challenging generation task i.e. Handwritten Mathematical Expression Generation (HMEG) from symbolic sequences. Since symbolic sequences are naturally graph-structured data we formulate HMEG as a graph-to-image (G2I) generation problem. Unlike the generation of natural images HMEG requires critic layout clarity for synthesizing correct and recognizable formulas but has no real masks available to supervise the learning process. To alleviate this challenge we propose a novel end-to-end G2I generation pipeline (i.e. graph - layout - mask - image) which requires no real masks or nondifferentiable alignment between layouts and masks. Technically to boost the capacity of predicting detailed relations among adjacent symbols we propose a Less-is-More (LiM) learning strategy. In addition we design a differentiable layout refinement module which maps bounding boxes to pixel-level soft masks so as to further alleviate ambiguous layout areas. Our whole model including layout prediction mask refinement and image generation can be jointly optimized in an end-to-end manner. Experimental results show that our model can generate high-quality HME images and outperforms previous generative methods. Besides a series of ablations study demonstrate effectiveness of the proposed techniques. Finally we validate that our generated images promisingly boosts the performance of HME recognition models through data augmentation. Our code and results are available at: https://github.com/AiArt-HDU/HMEG.
A Closer Look at the Few-Shot Adaptation of Large Vision-Language Models
Authors: Julio Silva-Rodríguez, Sina Hajimiri, Ismail Ben Ayed, Jose Dolz
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Efficient transfer learning (ETL) is receiving increasing attention to adapt large pre-trained language-vision models on downstream tasks with a few labeled samples. While significant progress has been made we reveal that state-of-the-art ETL approaches exhibit strong performance only in narrowly-defined experimental setups and with a careful adjustment of hyperparameters based on a large corpus of labeled samples. In particular we make two interesting and surprising empirical observations. First to outperform a simple Linear Probing baseline these methods require to optimize their hyper-parameters on each target task. And second they typically underperform --sometimes dramatically-- standard zero-shot predictions in the presence of distributional drifts. Motivated by the unrealistic assumptions made in the existing literature i.e. access to a large validation set and case-specific grid-search for optimal hyperparameters we propose a novel approach that meets the requirements of real-world scenarios. More concretely we introduce a CLass-Adaptive linear Probe (CLAP) objective whose balancing term is optimized via an adaptation of the general Augmented Lagrangian method tailored to this context. We comprehensively evaluate CLAP on a broad span of datasets and scenarios demonstrating that it consistently outperforms SoTA approaches while yet being a much more efficient alternative.
Generative Rendering: Controllable 4D-Guided Video Generation with 2D Diffusion Models
Authors: Shengqu Cai, Duygu Ceylan, Matheus Gadelha, Chun-Hao Paul Huang, Tuanfeng Yang Wang, Gordon Wetzstein
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Traditional 3D content creation tools empower users to bring their imagination to life by giving them direct control over a scene's geometry appearance motion and camera path. Creating computer-generated videos however is a tedious manual process which can be automated by emerging text-to-video diffusion models. Despite great promise video diffusion models are difficult to control hindering users to apply their creativity rather than amplifying it. To address this challenge we present a novel approach that combines the controllability of dynamic 3D meshes with the expressivity and editability of emerging diffusion models. For this purpose our approach takes an animated low-fidelity rendered mesh as input and injects the ground truth correspondence information obtained from the dynamic mesh into various stages of a pre-trained text-to-image generation model to output high-quality and temporally consistent frames. We demonstrate our approach on various examples where motion can be obtained by animating rigged assets or changing the camera path.
Relightable Gaussian Codec Avatars
Authors: Shunsuke Saito, Gabriel Schwartz, Tomas Simon, Junxuan Li, Giljoo Nam
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: The fidelity of relighting is bounded by both geometry and appearance representations. For geometry both mesh and volumetric approaches have difficulty modeling intricate structures like 3D hair geometry. For appearance existing relighting models are limited in fidelity and often too slow to render in real-time with high-resolution continuous environments. In this work we present Relightable Gaussian Codec Avatars a method to build high-fidelity relightable head avatars that can be animated to generate novel expressions. Our geometry model based on 3D Gaussians can capture 3D-consistent sub-millimeter details such as hair strands and pores on dynamic face sequences. To support diverse materials of human heads such as the eyes skin and hair in a unified manner we present a novel relightable appearance model based on learnable radiance transfer. Together with global illumination-aware spherical harmonics for the diffuse components we achieve real-time relighting with all-frequency reflections using spherical Gaussians. This appearance model can be efficiently relit under both point light and continuous illumination. We further improve the fidelity of eye reflections and enable explicit gaze control by introducing relightable explicit eye models. Our method outperforms existing approaches without compromising real-time performance. We also demonstrate real-time relighting of avatars on a tethered consumer VR headset showcasing the efficiency and fidelity of our avatars.
Why Not Use Your Textbook? Knowledge-Enhanced Procedure Planning of Instructional Videos
Authors: Kumaranage Ravindu Yasas Nagasinghe, Honglu Zhou, Malitha Gunawardhana, Martin Renqiang Min, Daniel Harari, Muhammad Haris Khan
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: In this paper we explore the capability of an agent to construct a logical sequence of action steps thereby assembling a strategic procedural plan. This plan is crucial for navigating from an initial visual observation to a target visual outcome as depicted in real-life instructional videos. Existing works have attained partial success by extensively leveraging various sources of information available in the datasets such as heavy intermediate visual observations procedural names or natural language step-by-step instructions for features or supervision signals. However the task remains formidable due to the implicit causal constraints in the sequencing of steps and the variability inherent in multiple feasible plans. To tackle these intricacies that previous efforts have overlooked we propose to enhance the agent's capabilities by infusing it with procedural knowledge. This knowledge sourced from training procedure plans and structured as a directed weighted graph equips the agent to better navigate the complexities of step sequencing and its potential variations. We coin our approach KEPP a novel Knowledge-Enhanced Procedure Planning system which harnesses a probabilistic procedural knowledge graph extracted from training data effectively acting as a comprehensive textbook for the training domain. Experimental evaluations across three widely-used datasets under settings of varying complexity reveal that KEPP attains superior state-of-the-art results while requiring only minimal supervision. Code and trained model are available at https://github.com/Ravindu-Yasas-Nagasinghe/KEPP
Global and Hierarchical Geometry Consistency Priors for Few-shot NeRFs in Indoor Scenes
Authors: Xiaotian Sun, Qingshan Xu, Xinjie Yang, Yu Zang, Cheng Wang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: It is challenging for Neural Radiance Fields (NeRFs) in the few-shot setting to reconstruct high-quality novel views and depth maps in 360^\circ outward-facing indoor scenes. The captured sparse views for these scenes usually contain large viewpoint variations. This greatly reduces the potential consistency between views leading NeRFs to degrade a lot in these scenarios. Existing methods usually leverage pretrained depth prediction models to improve NeRFs. However these methods cannot guarantee geometry consistency due to the inherent geometry ambiguity in the pretrained models thus limiting NeRFs' performance. In this work we present P\textsuperscript 2 NeRF to capture global and hierarchical geometry consistency priors from pretrained models thus facilitating few-shot NeRFs in 360^\circ outward-facing indoor scenes. On the one hand we propose a matching-based geometry warm-up strategy to provide global geometry consistency priors for NeRFs. This effectively avoids the overfitting of early training with sparse inputs. On the other hand we propose a group depth ranking loss and ray weight mask regularization based on the monocular depth estimation model. This provides hierarchical geometry consistency priors for NeRFs. As a result our approach can fully leverage the geometry consistency priors from pretrained models and help few-shot NeRFs achieve state-of-the-art performance on two challenging indoor datasets. Our code is released at https://github.com/XT5un/P2NeRF.
FreeKD: Knowledge Distillation via Semantic Frequency Prompt
Authors: Yuan Zhang, Tao Huang, Jiaming Liu, Tao Jiang, Kuan Cheng, Shanghang Zhang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Knowledge distillation (KD) has been applied to various tasks successfully and mainstream methods typically boost the student model via spatial imitation losses. However the consecutive downsamplings induced in the spatial domain of teacher model is a type of corruption hindering the student from analyzing what specific information needs to be imitated which results in accuracy degradation. To better understand the underlying pattern of corrupted feature maps we shift our attention to the frequency domain. During frequency distillation we encounter a new challenge: the low-frequency bands convey general but minimal context while the high are more informative but also introduce noise. Not each pixel within the frequency bands contributes equally to the performance. To address the above problem: (1) We propose the Frequency Prompt plugged into the teacher model absorbing the semantic frequency context during finetuning. (2) During the distillation period a pixel-wise frequency mask is generated via Frequency Prompt to localize those pixel of interests (PoIs) in various frequency bands. Additionally we employ a position-aware relational frequency loss for dense prediction tasks delivering a high-order spatial enhancement to the student model. We dub our Frequency Knowledge Distillation method as FreeKD which determines the optimal localization and extent for the frequency distillation. Extensive experiments demonstrate that FreeKD not only outperforms spatial-based distillation methods consistently on dense prediction tasks (e.g. FreeKD brings 3.8 AP gains for RepPoints-R50 on COCO2017 and 4.55 mIoU gains for PSPNet-R18 on Cityscapes) but also conveys more robustness to the student. Notably we also validate the generalization of our approach on large-scale vision models (e.g. DINO and SAM).
Can't Make an Omelette Without Breaking Some Eggs: Plausible Action Anticipation Using Large Video-Language Models
Authors: Himangi Mittal, Nakul Agarwal, Shao-Yuan Lo, Kwonjoon Lee
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: We introduce PlausiVL a large video-language model for anticipating action sequences that are plausible in the real-world. While significant efforts have been made towards anticipating future actions prior approaches do not take into account the aspect of plausibility in an action sequence. To address this limitation we explore the generative capability of a large video-language model in our work and further develop the understanding of plausibility in an action sequence by introducing two objective functions a counterfactual-based plausible action sequence learning loss and a long-horizon action repetition loss. We utilize temporal logical constraints as well as verb-noun action pair logical constraints to create implausible/counterfactual action sequences and use them to train the model with plausible action sequence learning loss. This loss helps the model to differentiate between plausible and not plausible action sequences and also helps the model to learn implicit temporal cues crucial for the task of action anticipation. The long-horizon action repetition loss puts a higher penalty on the actions that are more prone to repetition over a longer temporal window. With this penalization the model is able to generate diverse plausible action sequences. We evaluate our approach on two large-scale datasets Ego4D and EPIC-Kitchens-100 and show improvements on the task of action anticipation.
On the Estimation of Image-matching Uncertainty in Visual Place Recognition
Authors: Mubariz Zaffar, Liangliang Nan, Julian F. P. Kooij
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: In Visual Place Recognition (VPR) the pose of a query image is estimated by comparing the image to a map of reference images with known reference poses. As is typical for image retrieval problems a feature extractor maps the query and reference images to a feature space where a nearest neighbor search is then performed. However till recently little attention has been given to quantifying the confidence that a retrieved reference image is a correct match. Highly certain but incorrect retrieval can lead to catastrophic failure of VPR-based localization pipelines. This work compares for the first time the main approaches for estimating the image-matching uncertainty including the traditional retrieval-based uncertainty estimation more recent data-driven aleatoric uncertainty estimation and the compute-intensive geometric verification. We further formulate a simple baseline method "SUE" which unlike the other methods considers the freely-available poses of the reference images in the map. Our experiments reveal that a simple L2-distance between the query and reference descriptors is already a better estimate of image-matching uncertainty than current data-driven approaches. SUE outperforms the other efficient uncertainty estimation methods and its uncertainty estimates complement the computationally expensive geometric verification approach. Future works for uncertainty estimation in VPR should consider the baselines discussed in this work.
Mask Grounding for Referring Image Segmentation
Authors: Yong Xien Chng, Henry Zheng, Yizeng Han, Xuchong Qiu, Gao Huang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Referring Image Segmentation (RIS) is a challenging task that requires an algorithm to segment objects referred by free-form language expressions. Despite significant progress in recent years most state-of-the-art (SOTA) methods still suffer from considerable language-image modality gap at the pixel and word level. These methods generally 1) rely on sentence-level language features for language-image alignment and 2) lack explicit training supervision for fine-grained visual grounding. Consequently they exhibit weak object-level correspondence between visual and language features. Without well-grounded features prior methods struggle to understand complex expressions that require strong reasoning over relationships among multiple objects especially when dealing with rarely used or ambiguous clauses. To tackle this challenge we introduce a novel Mask Grounding auxiliary task that significantly improves visual grounding within language features by explicitly teaching the model to learn fine-grained correspondence between masked textual tokens and their matching visual objects. Mask Grounding can be directly used on prior RIS methods and consistently bring improvements. Furthermore to holistically address the modality gap we also design a cross-modal alignment loss and an accompanying alignment module. These additions work synergistically with Mask Grounding. With all these techniques our comprehensive approach culminates in MagNet (Mask-grounded Network) an architecture that significantly outperforms prior arts on three key benchmarks (RefCOCO RefCOCO+ and G-Ref) demonstrating our method's effectiveness in addressing current limitations of RIS algorithms. Our code and pre-trained weights will be released.
Single-to-Dual-View Adaptation for Egocentric 3D Hand Pose Estimation
Authors: Ruicong Liu, Takehiko Ohkawa, Mingfang Zhang, Yoichi Sato
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: The pursuit of accurate 3D hand pose estimation stands as a keystone for understanding human activity in the realm of egocentric vision. The majority of existing estimation methods still rely on single-view images as input leading to potential limitations e.g. limited field-of-view and ambiguity in depth. To address these problems adding another camera to better capture the shape of hands is a practical direction. However existing multi-view hand pose estimation methods suffer from two main drawbacks: 1) Requiring multi-view annotations for training which are expensive. 2) During testing the model becomes inapplicable if camera parameters/layout are not the same as those used in training. In this paper we propose a novel Single-to-Dual-view adaptation (S2DHand) solution that adapts a pre-trained single-view estimator to dual views. Compared with existing multi-view training methods 1) our adaptation process is unsupervised eliminating the need for multi-view annotation. 2) Moreover our method can handle arbitrary dual-view pairs with unknown camera parameters making the model applicable to diverse camera settings. Specifically S2DHand is built on certain stereo constraints including pair-wise cross-view consensus and invariance of transformation between both views. These two stereo constraints are used in a complementary manner to generate pseudo-labels allowing reliable adaptation. Evaluation results reveal that S2DHand achieves significant improvements on arbitrary camera pairs under both in-dataset and cross-dataset settings and outperforms existing adaptation methods with leading performance. Project page: https://github.com/ut-vision/S2DHand.
Time-Efficient Light-Field Acquisition Using Coded Aperture and Events
Authors: Shuji Habuchi, Keita Takahashi, Chihiro Tsutake, Toshiaki Fujii, Hajime Nagahara
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: We propose a computational imaging method for time-efficient light-field acquisition that combines a coded aperture with an event-based camera. Different from the conventional coded-aperture imaging method our method applies a sequence of coding patterns during a single exposure for an image frame. The parallax information which is related to the differences in coding patterns is recorded as events. The image frame and events all of which are measured in a single exposure are jointly used to computationally reconstruct a light field. We also designed an algorithm pipeline for our method that is end-to-end trainable on the basis of deep optics and compatible with real camera hardware. We experimentally showed that our method can achieve more accurate reconstruction than several other imaging methods with a single exposure. We also developed a hardware prototype with the potential to complete the measurement on the camera within 22 msec and demonstrated that light fields from real 3-D scenes can be obtained with convincing visual quality. Our software and supplementary video are available from our project website.
EVS-assisted Joint Deblurring Rolling-Shutter Correction and Video Frame Interpolation through Sensor Inverse Modeling
Authors: Rui Jiang, Fangwen Tu, Yixuan Long, Aabhaas Vaish, Bowen Zhou, Qinyi Wang, Wei Zhang, Yuntan Fang, Luis Eduardo Garcia Capel, Bo Mu, Tiejun Dai, Andreas Suess
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Event-based Vision Sensors (EVS) gain popularity in enhancing CMOS Image Sensor (CIS) video capture. Nonidealities of EVS such as pixel or readout latency can significantly influence the quality of the enhanced images and warrant dedicated consideration in the design of fusion algorithms. A novel approach for jointly computing deblurred rolling-shutter artifact corrected high-speed videos with frame rates up to 10000 FPS using inherently blurry rolling shutter CIS frames of 120 FPS to 150 FPS in conjunction with EVS data from a hybrid CIS-EVS sensor is presented. EVS pixel latency readout latency and the sensor's refractory period are explicitly incorporated into the measurement model. This inverse function problem is solved on a per-pixel manner using an optimization-based framework. The interpolated images are subsequently processed by a novel refinement network. The proposed method is evaluated using simulated and measured datasets under natural and controlled environments. Extensive experiments show reduced shadowing effect a 4 dB increment in PSNR and a 12% improvement in LPIPS score compared to state-of-the-art methods.
Prompt-Enhanced Multiple Instance Learning for Weakly Supervised Video Anomaly Detection
Authors: Junxi Chen, Liang Li, Li Su, Zheng-jun Zha, Qingming Huang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Weakly-supervised Video Anomaly Detection (wVAD) aims to detect frame-level anomalies using only video-level labels in training. Due to the limitation of coarse-grained labels Multi-Instance Learning (MIL) is prevailing in wVAD. However MIL suffers from insufficiency of binary supervision to model diverse abnormal patterns. Besides the coupling between abnormality and its context hinders the learning of clear abnormal event boundary. In this paper we propose prompt-enhanced MIL to detect various abnormal events while ensuring clear event boundaries. Concretely we design the abnormal-aware prompts by using abnormal class annotations together with learnable prompt which can incorporate semantic priors into video features dynamically. The detector can utilize the semantic-rich features to capture diverse abnormal patterns. In addition normal context prompt is introduced to amplify the distinction between abnormality and its context facilitating the generation of clear boundary. With the mutual enhancement of abnormal-aware and normal context prompt the model can construct discriminative representations to detect divergent anomalies without ambiguous event boundaries. Extensive experiments demonstrate our method achieves SOTA performance on three public benchmarks. The code is available at https://github.com/Junxi-Chen/PE-MIL.
FreeCustom: Tuning-Free Customized Image Generation for Multi-Concept Composition
Authors: Ganggui Ding, Canyu Zhao, Wen Wang, Zhen Yang, Zide Liu, Hao Chen, Chunhua Shen
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Benefiting from large-scale pre-trained text-to-image (T2I) generative models impressive progress has been achieved in customized image generation which aims to generate user-specified concepts. Existing approaches have extensively focused on single-concept customization and still encounter challenges when it comes to complex scenarios that involve combining multiple concepts. These approaches often require retraining/fine-tuning using a few images leading to time-consuming training processes and impeding their swift implementation. Furthermore the reliance on multiple images to represent a singular concept increases the difficulty of customization. To this end we propose FreeCustom a novel tuning-free method to generate customized images of multi-concept composition based on reference concepts using only one image per concept as input. Specifically we introduce a new multi-reference self-attention (MRSA) mechanism and a weighted mask strategy that enables the generated image to access and focus more on the reference concepts. In addition MRSA leverages our key finding that input concepts are better preserved when providing images with context interactions. Experiments show that our method's produced images are consistent with the given concepts and better aligned with the input text. Our method outperforms or performs on par with other training-based methods in terms of multi-concept composition and single-concept customization but is simpler. Codes can be found \href https://github.com/aim-uofa/FreeCustom  here .
Non-autoregressive Sequence-to-Sequence Vision-Language Models
Authors: Kunyu Shi, Qi Dong, Luis Goncalves, Zhuowen Tu, Stefano Soatto
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Sequence-to-sequence vision-language models are showing promise but their applicability is limited by their inference latency due to their autoregressive way of generating predictions. We propose a parallel decoding sequence-to-sequence vision-language model trained with a Query-CTC loss that marginalizes over multiple inference paths in the decoder. This allows us to model the joint distribution of tokens rather than restricting to conditional distribution as in an autoregressive model. The resulting model NARVL achieves performance on-par with its state-of-the-art autoregressive counterpart but is faster at inference time reducing from the linear complexity associated with the sequential generation of tokens to a paradigm of constant time joint inference.
MaskINT: Video Editing via Interpolative Non-autoregressive Masked Transformers
Authors: Haoyu Ma, Shahin Mahdizadehaghdam, Bichen Wu, Zhipeng Fan, Yuchao Gu, Wenliang Zhao, Lior Shapira, Xiaohui Xie
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Recent advances in generative AI have significantly enhanced image and video editing particularly in the context of text prompt control. State-of-the-art approaches predominantly rely on diffusion models to accomplish these tasks. However the computational demands of diffusion-based methods are substantial often necessitating large-scale paired datasets for training and therefore challenging the deployment in real applications. To address these issues this paper breaks down the text-based video editing task into two stages. First we leverage an pre-trained text-to-image diffusion model to simultaneously edit few keyframes in an zero-shot way. Second we introduce an efficient model called MaskINT which is built on non-autoregressive masked generative transformers and specializes in frame interpolation between the edited keyframes using the structural guidance from intermediate frames. Experimental results suggest that our MaskINT achieves comparable performance with diffusion-based methodologies while significantly improve the inference time. This research offers a practical solution for text-based video editing and showcases the potential of non-autoregressive masked generative transformers in this domain.
Active Prompt Learning in Vision Language Models
Authors: Jihwan Bang, Sumyeong Ahn, Jae-Gil Lee
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Pre-trained Vision Language Models (VLMs) have demonstrated notable progress in various zero-shot tasks such as classification and retrieval. Despite their performance because improving performance on new tasks requires task-specific knowledge their adaptation is essential. While labels are needed for the adaptation acquiring them is typically expensive. To overcome this challenge active learning a method of achieving a high performance by obtaining labels for a small number of samples from experts has been studied. Active learning primarily focuses on selecting unlabeled samples for labeling and leveraging them to train models. In this study we pose the question "how can the pre-trained VLMs be adapted under the active learning framework?" In response to this inquiry we observe that (1) simply applying a conventional active learning framework to pre-trained VLMs even may degrade performance compared to random selection because of the class imbalance in labeling candidates and (2) the knowledge of VLMs can provide hints for achieving the balance before labeling. Based on these observations we devise a novel active learning framework for VLMs denoted as PCB. To assess the effectiveness of our approach we conduct experiments on seven different real-world datasets and the results demonstrate that PCB surpasses conventional active learning and random sampling methods.
Learning Multi-Dimensional Human Preference for Text-to-Image Generation
Authors: Sixian Zhang, Bohan Wang, Junqiang Wu, Yan Li, Tingting Gao, Di Zhang, Zhongyuan Wang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Current metrics for text-to-image models typically rely on statistical metrics which inadequately represent the real preference of humans. Although recent work attempts to learn these preferences via human annotated images they reduce the rich tapestry of human preference to a single overall score. However the preference results vary when humans evaluate images with different aspects. Therefore to learn the multi-dimensional human preferences we propose the Multi-dimensional Preference Score (MPS) the first multi-dimensional preference scoring model for the evaluation of text-to-image models. The MPS introduces the preference condition module upon CLIP model to learn these diverse preferences. It is trained based on our Multi-dimensional Human Preference (MHP) Dataset which comprises 918315 human preference choices across four dimensions (i.e. aesthetics semantic alignment detail quality and overall assessment) on 607541 images. The images are generated by a wide range of latest text-to-image models. The MPS outperforms existing scoring methods across 3 datasets in 4 dimensions enabling it a promising metric for evaluating and improving text-to-image generation. The model and dataset will be made publicly available to facilitate future research.
ViVid-1-to-3: Novel View Synthesis with Video Diffusion Models
Authors: Jeong-gi Kwak, Erqun Dong, Yuhe Jin, Hanseok Ko, Shweta Mahajan, Kwang Moo Yi
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Generating novel views of an object from a single image is a challenging task. It requires an understanding of the underlying 3D structure of the object from an image and rendering high-quality spatially consistent new views. While recent methods for view synthesis based on diffusion have shown great progress achieving consistency among various view estimates and at the same time abiding by the desired camera pose remains a critical problem yet to be solved. In this work we demonstrate a strikingly simple method where we utilize a pre-trained video diffusion model to solve this problem. Our key idea is that synthesizing a novel view could be reformulated as synthesizing a video of a camera going around the object of interest---a scanning video---which then allows us to leverage the powerful priors that a video diffusion model would have learned. Thus to perform novel-view synthesis we create a smooth camera trajectory to the target view that we wish to render and denoise using both a view-conditioned diffusion model and a video diffusion model. By doing so we obtain a highly consistent novel view synthesis outperforming the state of the art.
Active Object Detection with Knowledge Aggregation and Distillation from Large Models
Authors: Dejie Yang, Yang Liu
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Accurately detecting active objects undergoing state changes is essential for comprehending human interactions and facilitating decision-making. The existing methods for active object detection (AOD) primarily rely on visual appearance of the objects within input such as changes in size shape and relationship with hands. However these visual changes can be subtle posing challenges particularly in scenarios with multiple distracting no-change instances of the same category. We observe that the state changes are often the result of an interaction being performed upon the object thus propose to use informed priors about object related plausible interactions (including semantics and visual appearance) to provide more reliable cues for AOD. Specifically we propose a knowledge aggregation procedure to integrate the aforementioned informed priors into oracle queries within the teacher decoder offering more object affordance commonsense to locate the active object. To streamline the inference process and reduce extra knowledge inputs we propose a knowledge distillation approach that encourages the student decoder to mimic the detection capabilities of the teacher decoder using the oracle query by replicating its predictions and attention. Our proposed framework achieves state-of-the-art performance on four datasets namely Ego4D Epic-Kitchens MECCANO and 100DOH which demonstrates the effectiveness of our approach in improving AOD. The code and models are available at https://github.com/idejie/KAD.git.
NICE: Neurogenesis Inspired Contextual Encoding for Replay-free Class Incremental Learning
Authors: Mustafa Burak Gurbuz, Jean Michael Moorman, Constantine Dovrolis
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Deep neural networks (DNNs) struggle to learn in dynamic settings because they mainly rely on static datasets. Continual learning (CL) aims to overcome this limitation by enabling DNNs to incrementally accumulate knowledge. A widely adopted scenario in CL is class-incremental learning (CIL) where DNNs are required to sequentially learn more classes. Among the various strategies in CL replay methods which revisit previous classes stand out as the only effective ones in CIL. Other strategies such as architectural modifications to segregate information across weights and protect them from change are ineffective in CIL. This is because they need additional information during testing to select the correct network parts to use. In this paper we propose NICE Neurogenesis Inspired Contextual Encoding a replay-free architectural method inspired by adult neurogenesis in the hippocampus. NICE groups neurons in the DNN based on different maturation stages and infers which neurons to use during testing without any additional signal. Through extensive experiments across 6 datasets and 3 architectures we show that NICE performs on par with or often outperforms replay methods. We also make the case that neurons exhibit highly distinctive activation patterns for the classes in which they specialize enabling us to determine when they should be used. The code is available at https://github.com/BurakGurbuz97/NICE.