GenAI4ELab/papercli-papers huggingface dataset:
Dr. Bokeh: DiffeRentiable Occlusion-aware Bokeh Rendering
Authors: Yichen Sheng; Zixun Yu; Lu Ling; Zhiwen Cao; Xuaner Zhang; Xin Lu; Ke Xian; Haiting Lin; Bedrich Benes
Venue: CVPR 2024 (main)

Abstract: Bokeh is widely used in photography to draw attention to the subject while effectively isolating distractions in the background. Computational methods can simulate bokeh effects without relying on a physical camera lens but the inaccurate lens modeling in existing filtering-based methods leads to artifacts that need post-processing or learning-based methods to fix. We propose Dr.Bokeh a novel rendering method that addresses the issue by directly correcting the defect that violates the physics in the current filtering-based bokeh rendering equation. Dr.Bokeh first preprocesses the input RGBD to obtain a layered scene representation. Dr.Bokeh then takes the layered representation and user-defined lens parameters to render photo-realistic lens blur based on the novel occlusion-aware bokeh rendering method. Experiments show that the non-learning based renderer Dr.Bokeh outperforms state-of-the-art bokeh rendering algorithms in terms of photo-realism. In addition extensive quantitative and qualitative evaluations show the more accurate lens model further pushes the limit of a closely related field depth-from-defocus.
Unsegment Anything by Simulating Deformation
Authors: Jiahao Lu; Xingyi Yang; Xinchao Wang
Venue: CVPR 2024 (main)

Abstract: Foundation segmentation models while powerful pose a significant risk: they enable users to effortlessly extract any objects from any digital content with a single click potentially leading to copyright infringement or malicious misuse. To mitigate this risk we introduce a new task "Anything Unsegmentable" to grant any image "the right to be unsegmented". The ambitious pursuit of the task is to achieve highly transferable adversarial attack against all prompt-based segmentation models regardless of model parameterizations and prompts. We highlight the non-transferable and heterogeneous nature of prompt-specific adversarial noises. Our approach focuses on disrupting image encoder features to achieve prompt-agnostic attacks. Intriguingly targeted feature attacks exhibit better transferability compared to untargeted ones suggesting the optimal update direction aligns with the image manifold. Based on the observations we design a novel attack named Unsegment Anything by Simulating Deformation (UAD). Our attack optimizes a differentiable deformation function to create a target deformed image which alters structural information while preserving achievable feature distance by adversarial example. Extensive experiments verify the effectiveness of our approach compromising a variety of promptable segmentation models with different architectures and prompt interfaces.
Transductive Zero-Shot and Few-Shot CLIP
Authors: Ségolène Martin; Yunshi Huang; Fereshteh Shakeri; Jean-Christophe Pesquet; Ismail Ben Ayed
Venue: CVPR 2024 (main)

Abstract: Transductive inference has been widely investigated in few-shot image classification but completely overlooked in the recent fast growing literature on adapting vision-langage models like CLIP. This paper addresses the transductive zero-shot and few-shot CLIP classification challenge in which inference is performed jointly across a mini-batch of unlabeled query samples rather than treating each instance independently. This paper addresses the transductive zero-shot and few-shot CLIP classification challenge in which inference is performed jointly across a mini-batch of unlabeled query samples rather than treating each instance independently. We initially construct informative vision-text probability features leading to a classification problem on the unit simplex set. Inspired by Expectation-Maximization (EM) our optimization-based classifying objective models the data probability distribution for each class using a Dirichlet law. The minimization problem is then tackled with a novel block Majorization-Minimization algorithm which simultaneously estimates the distribution parameters and class assignments. Extensivenumerical experiments on 11 datasets underscore the benefits and efficacy of our batch inference approach. On zero-shot tasks with test batches of 75 samples our approach yields near 20% improvement in ImageNet accuracy over CLIP's zero-shot performance. Additionally we outperform state-of-the-art methods in the few-shot setting. Code is available at https://github.com/SegoleneMartin/transductive-CLIP.
Deep Single Image Camera Calibration by Heatmap Regression to Recover Fisheye Images Under Manhattan World Assumption
Authors: Nobuhiko Wakai; Satoshi Sato; Yasunori Ishii; Takayoshi Yamashita
Venue: CVPR 2024 (main)

Abstract: A Manhattan world lying along cuboid buildings is useful for camera angle estimation. However accurate and robust angle estimation from fisheye images in the Manhattan world has remained an open challenge because general scene images tend to lack constraints such as lines arcs and vanishing points. To achieve higher accuracy and robustness we propose a learning-based calibration method that uses heatmap regression which is similar to pose estimation using keypoints to detect the directions of labeled image coordinates. Simultaneously our two estimators recover the rotation and remove fisheye distortion by remapping from a general scene image. Without considering vanishing-point constraints we find that additional points for learning-based methods can be defined. To compensate for the lack of vanishing points in images we introduce auxiliary diagonal points that have the optimal 3D arrangement of spatial uniformity. Extensive experiments demonstrated that our method outperforms conventional methods on large-scale datasets and with off-the-shelf cameras.
ID-Blau: Image Deblurring by Implicit Diffusion-based reBLurring AUgmentation
Authors: Jia-Hao Wu; Fu-Jen Tsai; Yan-Tsung Peng; Chung-Chi Tsai; Chia-Wen Lin; Yen-Yu Lin
Venue: CVPR 2024 (main)

Abstract: Image deblurring aims to remove undesired blurs from an image captured in a dynamic scene. Much research has been dedicated to improving deblurring performance through model architectural designs. However there is little work on data augmentation for image deblurring. Since continuous motion causes blurred artifacts during image exposure we aspire to develop a groundbreaking blur augmentation method to generate diverse blurred images by simulating motion trajectories in a continuous space. This paper proposes Implicit Diffusion-based reBLurring AUgmentation (ID-Blau) utilizing a sharp image paired with a controllable blur condition map to produce a corresponding blurred image. We parameterize the blur patterns of a blurred image with their orientations and magnitudes as a pixel-wise blur condition map to simulate motion trajectories and implicitly represent them in a continuous space. By sampling diverse blur conditions ID-Blau can generate various blurred images unseen in the training set. Experimental results demonstrate that ID-Blau can produce realistic blurred images for training and thus significantly improve performance for state-of-the-art deblurring models. The source code is available at https://github.com/plusgood-steven/ID-Blau.
LAENeRF: Local Appearance Editing for Neural Radiance Fields
Authors: Lukas Radl; Michael Steiner; Andreas Kurz; Markus Steinberger
Venue: CVPR 2024 (main)

Abstract: Due to the omnipresence of Neural Radiance Fields (NeRFs) the interest towards editable implicit 3D representations has surged over the last years. However editing implicit or hybrid representations as used for NeRFs is difficult due to the entanglement of appearance and geometry encoded in the model parameters. Despite these challenges recent research has shown first promising steps towards photorealistic and non-photorealistic appearance edits. The main open issues of related work include limited interactivity a lack of support for local edits and large memory requirements rendering them less useful in practice. We address these limitations with LAENeRF a unified framework for photorealistic and non-photorealistic appearance editing of NeRFs. To tackle local editing we leverage a voxel grid as starting point for region selection. We learn a mapping from expected ray terminations to final output color which can optionally be supervised by a style loss resulting in a framework which can perform photorealistic and non-photorealistic appearance editing of selected regions. Relying on a single point per ray for our mapping we limit memory requirements and enable fast optimization. To guarantee interactivity we compose the output color using a set of learned modifiable base colors composed with additive layer mixing. Compared to concurrent work LAENeRF enables recoloring and stylization while keeping processing time low. Furthermore we demonstrate that our approach surpasses baseline methods both quantitatively and qualitatively.
CSTA: CNN-based Spatiotemporal Attention for Video Summarization
Authors: Jaewon Son; Jaehun Park; Kwangsu Kim
Venue: CVPR 2024 (main)

Abstract: Video summarization aims to generate a concise representation of a video capturing its essential content and key moments while reducing its overall length. Although several methods employ attention mechanisms to handle long-term dependencies they often fail to capture the visual significance inherent in frames. To address this limitation we propose a CNN-based SpatioTemporal Attention (CSTA) method that stacks each feature of frames from a single video to form image-like frame representations and applies 2D CNN to these frame features. Our methodology relies on CNN to comprehend the inter and intra-frame relations and to find crucial attributes in videos by exploiting its ability to learn absolute positions within images. In contrast to previous work compromising efficiency by designing additional modules to focus on spatial importance CSTA requires minimal computational overhead as it uses CNN as a sliding window. Extensive experiments on two benchmark datasets (SumMe and TVSum) demonstrate that our proposed approach achieves state-of-the-art performance with fewer MACs compared to previous methods. Codes are available at https://github.com/thswodnjs3/CSTA.
Adversarial Score Distillation: When score distillation meets GAN
Authors: Min Wei; Jingkai Zhou; Junyao Sun; Xuesong Zhang
Venue: CVPR 2024 (main)

Abstract: Existing score distillation methods are sensitive to classifier-free guidance (CFG) scale manifested as over-smoothness or instability at small CFG scales while over-saturation at large ones. To explain and analyze these issues we revisit the derivation of Score Distillation Sampling (SDS) and decipher existing score distillation with the Wasserstein Generative Adversarial Network (WGAN) paradigm. With the WGAN paradigm we find that existing score distillation either employs a fixed sub-optimal discriminator or conducts incomplete discriminator optimization resulting in the scale-sensitive issue. We propose the Adversarial Score Distillation (ASD) which maintains an optimizable discriminator and updates it using the complete optimization objective. Experiments show that the proposed ASD performs favorably in 2D distillation and text-to-3D tasks against existing methods. Furthermore to explore the generalization ability of our paradigm we extend ASD to the image editing task which achieves competitive results. The project page and code are at https://github.com/2y7c3/ASD
Decentralized Directed Collaboration for Personalized Federated Learning
Authors: Yingqi Liu; Yifan Shi; Qinglun Li; Baoyuan Wu; Xueqian Wang; Li Shen
Venue: CVPR 2024 (main)

Abstract: Personalized Federated Learning (PFL) is proposed to find the greatest personalized models for each client. To avoid the central failure and communication bottleneck in the server-based FL we concentrate on the Decentralized Personalized Federated Learning (DPFL) that performs distributed model training in a Peer-to-Peer (P2P) manner. Most personalized works in DPFL are based on undirected and symmetric topologies however the data computation and communication resources heterogeneity result in large variances in the personalized models which lead the undirected aggregation to suboptimal personalized performance and unguaranteed convergence. To address these issues we propose a directed collaboration DPFL framework by incorporating stochastic gradient push and partial model personalized called Decentralized Federated Partial Gradient Push (DFedPGP). It personalizes the linear classifier in the modern deep model to customize the local solution and learns a consensus representation in a fully decentralized manner. Clients only share gradients with a subset of neighbors based on the directed and asymmetric topologies which guarantees flexible choices for resource efficiency and better convergence. Theoretically we show that the proposed DFedPGP achieves a superior convergence rate of O(1/?T) in the general non-convex setting and tighter connectivity among clients will speed up the convergence. The proposed method achieves state-of-the-art (SOTA) accuracy in both data and computation heterogeneity scenarios demonstrating the efficiency of the directed collaboration and partial gradient push.
Vector Graphics Generation via Mutually Impulsed Dual-domain Diffusion
Authors: Zhongyin Zhao; Ye Chen; Zhangli Hu; Xuanhong Chen; Bingbing Ni
Venue: CVPR 2024 (main)

Abstract: Intelligent generation of vector graphics has very promising applications in the fields of advertising and logo design artistic painting animation production etc. However current mainstream vector image generation methods lack the encoding of image appearance information that is associated with the original vector representation and therefore lose valid supervision signal from the strong correlation between the discrete vector parameter (drawing instruction) sequence and the target shape/structure of the corresponding pixel image. On the one hand the generation process based on pure vector domain completely ignores the similarity measurement between shape parameter (and their combination) and the paired pixel image appearance pattern; on the other hand two-stage methods (i.e. generation-and-vectorization) based on pixel diffusion followed by differentiable image-to-vector translation suffer from wrong error-correction signal caused by approximate gradients. To address the above issues we propose a novel generation framework based on dual-domain (vector-pixel) diffusion with cross-modality impulse signals from each other. First in each diffusion step the current representation extracted from the other domain is used as a condition variable to constrain the subsequent sampling operation yielding shape-aware new parameterizations; second independent supervision signals from both domains avoid the gradient error accumulation problem caused by cross-domain representation conversion. Extensive experimental results on popular benchmarks including font and icon datasets demonstrate the great advantages of our proposed framework in terms of generated shape quality.
PEM: Prototype-based Efficient MaskFormer for Image Segmentation
Authors: Niccolò Cavagnero; Gabriele Rosi; Claudia Cuttano; Francesca Pistilli; Marco Ciccone; Giuseppe Averta; Fabio Cermelli
Venue: CVPR 2024 (main)

Abstract: Recent transformer-based architectures have shown impressive results in the field of image segmentation. Thanks to their flexibility they obtain outstanding performance in multiple segmentation tasks such as semantic and panoptic under a single unified framework. To achieve such impressive performance these architectures employ intensive operations and require substantial computational resources which are often not available especially on edge devices. To fill this gap we propose Prototype-based Efficient MaskFormer (PEM) an efficient transformer-based architecture that can operate in multiple segmentation tasks. PEM proposes a novel prototype-based cross-attention which leverages the redundancy of visual features to restrict the computation and improve the efficiency without harming the performance. In addition PEM introduces an efficient multi-scale feature pyramid network capable of extracting features that have high semantic content in an efficient way thanks to the combination of deformable convolutions and context-based self-modulation. We benchmark the proposed PEM architecture on two tasks semantic and panoptic segmentation evaluated on two different datasets Cityscapes and ADE20K. PEM demonstrates outstanding performance on every task and dataset outperforming task-specific architectures while being comparable and even better than computationally expensive baselines. Code is available at https://github.com/NiccoloCavagnero/PEM.
Referring Expression Counting
Authors: Siyang Dai; Jun Liu; Ngai-Man Cheung
Venue: CVPR 2024 (main)

Abstract: Existing counting tasks are limited to the class level which don't account for fine-grained details within the class. In real applications it often requires in-context or referring human input for counting target objects. Take urban analysis as an example fine-grained information such as traffic flow in different directions pedestrians and vehicles waiting or moving at different sides of the junction is more beneficial. Current settings of both class-specific and class-agnostic counting treat objects of the same class indifferently which pose limitations in real use cases. To this end we propose a new task named Referring Expression Counting (REC) which aims to count objects with different attributes within the same class. To evaluate the REC task we create a novel dataset named REC-8K which contains 8011 images and 17122 referring expressions. Experiments on REC-8K show that our proposed method achieves state-of-the-art performance compared with several text-based counting methods and an open-set object detection model. We also outperform prior models on the class agnostic counting (CAC) benchmark [36] for the zero-shot setting and perform on par with the few-shot methods. Code and dataset is available at https://github.com/sydai/referring-expression-counting.
ScoreHypo: Probabilistic Human Mesh Estimation with Hypothesis Scoring
Authors: Yuan Xu; Xiaoxuan Ma; Jiajun Su; Wentao Zhu; Yu Qiao; Yizhou Wang
Venue: CVPR 2024 (main)

Abstract: Monocular 3D human mesh estimation is an ill-posed problem characterized by inherent ambiguity and occlusion. While recent probabilistic methods propose generating multiple solutions little attention is paid to obtaining high-quality estimates from them. To address this limitation we introduce ScoreHypo a versatile framework by first leverages our novel HypoNet to generate multiple hypotheses followed by employing a meticulously designed scorer ScoreNet to evaluate and select high-quality estimates. ScoreHypo formulates the estimation process as a reverse denoising process where HypoNet produces a diverse set of plausible estimates that effectively align with the image cues. Subsequently ScoreNet is employed to rigorously evaluate and rank these estimates based on their quality and finally identify superior ones. Experimental results demonstrate that HypoNet outperforms existing state-of-the-art probabilistic methods as a multi-hypothesis mesh estimator. Moreover the estimates selected by ScoreNet significantly outperform random generation or simple averaging. Notably the trained ScoreNet exhibits generalizability as it can effectively score existing methods and significantly reduce their errors by more than 15%. Code and models are available at https://xy02-05.github.io/ScoreHypo.
GES : Generalized Exponential Splatting for Efficient Radiance Field Rendering
Authors: Abdullah Hamdi; Luke Melas-Kyriazi; Jinjie Mai; Guocheng Qian; Ruoshi Liu; Carl Vondrick; Bernard Ghanem; Andrea Vedaldi
Venue: CVPR 2024 (main)

Abstract: Advancements in 3D Gaussian Splatting have significantly accelerated 3D reconstruction and generation. However it may require a large number of Gaussians which creates a substantial memory footprint. This paper introduces GES (Generalized Exponential Splatting) a novel representation that employs Generalized Exponential Function (GEF) to model 3D scenes requiring far fewer particles to represent a scene and thus significantly outperforming Gaussian Splatting methods in efficiency with a plug-and-play replacement ability for Gaussian-based utilities. GES is validated theoretically and empirically in both principled 1D setup and realistic 3D scenes. It is shown to represent signals with sharp edges more accurately which are typically challenging for Gaussians due to their inherent low-pass characteristics. Our empirical analysis demonstrates that GEF outperforms Gaussians in fitting natural-occurring signals (E.g. squares triangles parabolic signals) thereby reducing the need for extensive splitting operations that increase the memory footprint of Gaussian Splatting. With the aid of a frequency-modulated loss GES achieves competitive performance in novel-view synthesis benchmarks while requiring less than half the memory storage of Gaussian Splatting and increasing the rendering speed by up to 39%. The code is available on the project website https://abdullahamdi.com/ges .
Learning to Predict Activity Progress by Self-Supervised Video Alignment
Authors: Gerard Donahue; Ehsan Elhamifar
Venue: CVPR 2024 (main)

Abstract: In this paper we tackle the problem of self-supervised video alignment and activity progress prediction using in-the-wild videos. Our proposed self-supervised representation learning method carefully addresses different action orderings redundant actions and background frames to generate improved video representations compared to previous methods. Our model generalizes temporal cycle-consistency learning to allow for more flexibility in determining cycle-consistent neighbors. More specifically to handle repeated actions we propose a multi-neighbor cycle consistency and a multi-cycle-back regression loss by finding multiple soft nearest neighbors using a Gaussian Mixture Model. To handle background and redundant frames we introduce a context-dependent drop function in our framework discouraging the alignment of droppable frames. On the other hand to learn from videos of multiple activities jointly we propose a multi-head crosstask network allowing us to embed a video and estimate progress without knowing its activity label. Experiments on multiple datasets show that our method outperforms the state-of-the-art for video alignment and progress prediction.
VicTR: Video-conditioned Text Representations for Activity Recognition
Authors: Kumara Kahatapitiya; Anurag Arnab; Arsha Nagrani; Michael S. Ryoo
Venue: CVPR 2024 (main)

Abstract: Vision-Language models (VLMs) have excelled in the image-domain--- especially in zero-shot settings--- thanks to the availability of vast pretraining data (i.e. paired image-text samples). However for videos such paired data is not as abundant. Therefore video-VLMs are usually designed by adapting pretrained image-VLMs to the video-domain instead of training from scratch. All such recipes rely on augmenting visual embeddings with temporal information (i.e. image --> video) often keeping text embeddings unchanged or even being discarded. In this paper we argue the contrary that better video-VLMs can be designed by focusing more on augmenting text rather than visual information. More specifically we introduce Video-conditioned Text Representations (VicTR): a form of text embeddings optimized w.r.t. visual embeddings creating a more-flexible contrastive latent space. Our model can further make use of freely-available semantic information in the form of visually-grounded auxiliary text (e.g. object or scene information). We evaluate our model on few-shot zero-shot (HMDB-51 UCF-101) short-form (Kinetics-400) and long-form (Charades) activity recognition benchmarks showing strong performance among video-VLMs.