We introduce Gaussian Articulated Template Model (GART) an explicit efficient and expressive representation for non-rigid articulated subject capturing and rendering from monocular videos. GART utilizes a mixture of moving 3D Gaussians to explicitly approximate a deformable subject's geometry and appearance. It takes advantage of a categorical template model prior (SMPL SMAL etc.) with learnable forward skinning while further generalizing to more complex non-rigid deformations with novel latent bones. GART can be reconstructed via differentiable rendering from monocular videos in seconds or minutes and rendered in novel poses faster than 150fps.
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Diffusion models have recently brought a powerful revolution in image generation. Despite showing impressive generative capabilities most of these models rely on the current sample to denoise the next one possibly resulting in denoising instability. In this paper we reinterpret the iterative denoising process as model optimization and leverage a moving average mechanism to ensemble all the prior samples. Instead of simply applying moving average to the denoised samples at different timesteps we first map the denoised samples to data space and then perform moving average to avoid distribution shift across timesteps. In view that diffusion models evolve the recovery from low-frequency components to high-frequency details we further decompose the samples into different frequency components and execute moving average separately on each component. We name the complete approach "Moving Average Sampling in Frequency domain (MASF)". MASF could be seamlessly integrated into mainstream pre-trained diffusion models and sampling schedules. Extensive experiments on both unconditional and conditional diffusion models demonstrate that our MASF leads to superior performances compared to the baselines with almost negligible additional complexity cost.
Transformers have been successfully applied in the field of video-based 3D human pose estimation. However the high computational costs of these video pose transformers (VPTs) make them impractical on resource-constrained devices. In this paper we present a plug-and-play pruning-and-recovering framework called Hourglass Tokenizer (HoT) for efficient transformer-based 3D human pose estimation from videos. Our HoT begins with pruning pose tokens of redundant frames and ends with recovering full-length tokens resulting in a few pose tokens in the intermediate transformer blocks and thus improving the model efficiency. To effectively achieve this we propose a token pruning cluster (TPC) that dynamically selects a few representative tokens with high semantic diversity while eliminating the redundancy of video frames. In addition we develop a token recovering attention (TRA) to restore the detailed spatio-temporal information based on the selected tokens thereby expanding the network output to the original full-length temporal resolution for fast inference. Extensive experiments on two benchmark datasets (i.e. Human3.6M and MPI-INF-3DHP) demonstrate that our method can achieve both high efficiency and estimation accuracy compared to the original VPT models. For instance applying to MotionBERT and MixSTE on Human3.6M our HoT can save nearly 50% FLOPs without sacrificing accuracy and nearly 40% FLOPs with only 0.2% accuracy drop respectively. Code and models are available at https://github.com/NationalGAILab/HoT.
The challenge of open-vocabulary recognition lies in the model has no clue of new categories it is applied to. Existing works have proposed different methods to embed category cues into the model e.g. through few-shot fine-tuning providing category names or textual descriptions to Vision-Language Models. Fine-tuning is time-consuming and degrades the generalization capability. Textual descriptions could be ambiguous and fail to depict visual details. This paper tackles open-vocabulary recognition from a different perspective by referring to multi-modal clues composed of textual descriptions and exemplar images. Our method named OVMR adopts two innovative components to pursue a more robust category cues embedding. A multi-modal classifier is first generated by dynamically complementing textual descriptions with image exemplars. A preference-based refinement module is hence applied to fuse uni-modal and multi-modal classifiers with the aim to alleviate issues of low-quality exemplar images or textual descriptions. The proposed OVMR is a plug-and-play module and works well with exemplar images randomly crawled from the Internet. Extensive experiments have demonstrated the promising performance of OVMR e.g. it outperforms existing methods across various scenarios and setups. Codes are publicly available at \href https://github.com/Zehong-Ma/OVMR https://github.com/Zehong-Ma/OVMR .
FMA-Net: Flow-Guided Dynamic Filtering and Iterative Feature Refinement with Multi-Attention for Joint Video Super-Resolution and Deblurring
PDF ↗We present a joint learning scheme of video super-resolution and deblurring called VSRDB to restore clean high-resolution (HR) videos from blurry low-resolution (LR) ones. This joint restoration problem has drawn much less attention compared to single restoration problems. In this paper we propose a novel flow-guided dynamic filtering (FGDF) and iterative feature refinement with multi-attention (FRMA) which constitutes our VSRDB framework denoted as FMA-Net. Specifically our proposed FGDF enables precise estimation of both spatio-temporally-variant degradation and restoration kernels that are aware of motion trajectories through sophisticated motion representation learning. Compared to conventional dynamic filtering the FGDF enables the FMA-Net to effectively handle large motions into the VSRDB. Additionally the stacked FRMA blocks trained with our novel temporal anchor (TA) loss which temporally anchors and sharpens features refine features in a coarse-to-fine manner through iterative updates. Extensive experiments demonstrate the superiority of the proposed FMA-Net over state-of-the-art methods in terms of both quantitative and qualitative quality. Codes and pre-trained models are available at: https://kaist-viclab.github.io/fmanet-site.
DSL-FIQA: Assessing Facial Image Quality via Dual-Set Degradation Learning and Landmark-Guided Transformer
PDF ↗Generic Face Image Quality Assessment (GFIQA) evaluates the perceptual quality of facial images which is crucial in improving image restoration algorithms and selecting high-quality face images for downstream tasks. We present a novel transformer-based method for GFIQA which is aided by two unique mechanisms. First a novel Dual-Set Degradation Representation Learning (DSL) mechanism uses facial images with both synthetic and real degradations to decouple degradation from content ensuring generalizability to real-world scenarios. This self-supervised method learns degradation features on a global scale providing a robust alternative to conventional methods that use local patch information in degradation learning. Second our transformer leverages facial landmarks to emphasize visually salient parts of a face image in evaluating its perceptual quality. We also introduce a balanced and diverse Comprehensive Generic Face IQA (CGFIQA-40k) dataset of 40K images carefully designed to overcome the biases in particular the imbalances in skin tone and gender representation in existing datasets. Extensive analysis and evaluation demonstrate the robustness of our method marking a significant improvement over prior methods.
Video Frame Interpolation (VFI) has witnessed a surge in popularity due to its abundant downstream applications. Event-based VFI (E-VFI) has recently propelled the advancement of VFI. Thanks to the high temporal resolution benefits event cameras can bridge the informational void present between successive video frames. Most state-of-the-art E-VFI methodologies follow the conventional VFI paradigm which pivots on motion estimation between consecutive frames to generate intermediate frames through a process of warping and refinement. However this reliance engenders a heavy dependency on the quality and consistency of keyframes rendering these methods susceptible to challenges in extreme real-world scenarios such as missing moving objects and severe occlusion dilemmas. This study proposes a novel E-VFI framework that directly synthesize intermediate frames leveraging event-based reference obviating the necessity for explicit motion estimation and substantially enhancing the capacity to handle motion occlusion. Given the sparse and inherently noisy nature of event data we prioritize the reliability of the event-based reference leading to the development of an innovative event-aware reconstruction strategy for accurate reference generation. Besides we implement a bi-directional event-guided alignment from keyframes to the reference using the introduced E-PCD module. Finally a transformer-based decoder is adopted for prediction refinement. Comprehensive experimental evaluations on both synthetic and real-world datasets underscore the superiority of our approach and its potential to execute high-quality VFI tasks.
This paper proposes Retrieval-Enhanced Asymmetric Diffusion (READ) for image-based robot motion planning. Given an image of the scene READ retrieves an initial motion from a database of image-motion pairs and uses a diffusion model to refine the motion for the given scene. Unlike prior retrieval-based diffusion models that require long forward-reverse diffusion paths READ directly diffuses between the source (retrieved) and target motions resulting in an efficient diffusion path. A second contribution of READ is its use of asymmetric diffusion whereby it preserves the kinematic feasibility of the generated motion by forward diffusion in a low-dimensional latent space while achieving high-resolution motion by reverse diffusion in the original task space using cold diffusion. Experimental results on various manipulation tasks demonstrate that READ outperforms state-of-the-art planning methods while ablation studies elucidate the contributions of asymmetric diffusion.
Deep Convolutional Neural Networks (DCNNs) have achieved remarkable performance in synthetic aperture radar (SAR) object detection but this comes at the cost of tremendous computational resources partly due to extracting redundant features within a single convolutional layer. Recent works either delve into model compression methods or focus on the carefully-designed lightweight models both of which result in performance degradation. In this paper we propose an efficient convolution module for SAR object detection called SFS-Conv which increases feature diversity within each convolutional layer through a shunt-perceive-select strategy. Specifically we shunt input feature maps into space and frequency aspects. The former perceives the context of various objects by dynamically adjusting receptive field while the latter captures abundant frequency variations and textural features via fractional Gabor transformer. To adaptively fuse features from space and frequency aspects a parameter-free feature selection module is proposed to ensure that the most representative and distinctive information are preserved. With SFS-Conv we build a lightweight SAR object detection network called SFS-CNet. Experimental results show that SFS-CNet outperforms state-of-the-art (SoTA) models on a series of SAR object detection benchmarks while simultaneously reducing both the model size and computational cost.
Infer from What You Have Seen Before: Temporally-dependent Classifier for Semi-supervised Video Segmentation
PDF ↗Due to high expense of human labor one major challenge for semantic segmentation in real-world scenarios is the lack of sufficient pixel-level labels which is more serious when processing video data. To exploit unlabeled data for model training semi-supervised learning methods attempt to construct pseudo labels or various auxiliary constraints as supervision signals. However most of them just process video data as a set of independent images in a per-frame manner. The rich temporal relationships are ignored which can serve as valuable clues for representation learning. Besides this per-frame recognition paradigm is quite different from that of humans. Actually benefited from the internal temporal relevance of video data human would wisely use the distinguished semantic concepts in historical frames to aid the recognition of the current frame. Motivated by this observation we propose a novel temporally-dependent classifier (TDC) to mimic the human-like recognition procedure. Comparing to the conventional classifier TDC can guide the model to learn a group of temporally-consistent semantic concepts across frames which essentially provides an implicit and effective constraint. We conduct extensive experiments on Cityscapes and CamVid and the results demonstrate the superiority of our proposed method to previous state-of-the-art methods. The code is available at https://github.com/jfzhuang/TDC.
Existing NeRF-based inverse rendering methods suppose that scenes are exclusively illuminated by distant light sources neglecting the potential influence of emissive sources within a scene. In this work we confront this limitation using LDR multi-view images captured with emissive sources turned on and off. Two key issues must be addressed: 1) ambiguity arising from the limited dynamic range along with unknown lighting details and 2) the expensive computational cost in volume rendering to backtrace the paths leading to final object colors. We present a novel approach ESR-NeRF leveraging neural networks as learnable functions to represent ray-traced fields. By training networks to satisfy light transport segments we regulate outgoing radiances progressively identifying emissive sources while being aware of reflection areas. The results on scenes encompassing emissive sources with various properties demonstrate the superiority of ESR-NeRF in qualitative and quantitative ways. Our approach also extends its applicability to the scenes devoid of emissive sources achieving lower CD metrics on the DTU dataset.
Depth completion aims to derive a dense depth map from sparse depth measurements with a synchronized color image. Current state-of-the-art (SOTA) methods are predominantly propagation-based which work as an iterative refinement on the initial estimated dense depth. However the initial depth estimations mostly result from direct applications of convolutional layers on the sparse depth map. In this paper we present a Bilateral Propagation Network (BP-Net) that propagates depth at the earliest stage to avoid directly convolving on sparse data. Specifically our approach propagates the target depth from nearby depth measurements via a non-linear model whose coefficients are generated through a multi-layer perceptron conditioned on both radiometric difference and spatial distance. By integrating bilateral propagation with multi-modal fusion and depth refinement in a multi-scale framework our BP-Net demonstrates outstanding performance on both indoor and outdoor scenes. It achieves SOTA on the NYUv2 dataset and ranks 1st on the KITTI depth completion benchmark at the time of submission. Experimental results not only show the effectiveness of bilateral propagation but also emphasize the significance of early-stage propagation in contrast to the refinement stage. Our code and trained models will be available on the project page.
Many contemporary studies utilize grid-based models for neural field representation but a systematic analysis of grid-based models is still missing hindering the improvement of those models. Therefore this paper introduces a theoretical framework for grid-based models. This framework points out that these models' approximation and generalization behaviors are determined by grid tangent kernels (GTK) which are intrinsic properties of grid-based models. The proposed framework facilitates a consistent and systematic analysis of diverse grid-based models. Furthermore the introduced framework motivates the development of a novel grid-based model named the Multiplicative Fourier Adaptive Grid (MulFAGrid). The numerical analysis demonstrates that MulFAGrid exhibits a lower generalization bound than its predecessors indicating its robust generalization performance. Empirical studies reveal that MulFAGrid achieves state-of-the-art performance in various tasks including 2D image fitting 3D signed distance field (SDF) reconstruction and novel view synthesis demonstrating superior representation ability. The project website is available at https://sites.google.com/view/cvpr24-2034-submission/home.
Recent studies have shown promising performance in open-vocabulary object detection (OVD) by utilizing pseudo labels (PLs) from pretrained vision and language models (VLMs). However teacher-student self-training a powerful and widely used paradigm to leverage PLs is rarely explored for OVD. This work identifies two challenges of using self-training in OVD: noisy PLs from VLMs and frequent distribution changes of PLs. To address these challenges we propose SAS-Det that tames self-training for OVD from two key perspectives. First we present a split-and-fusion (SAF) head that splits a standard detection into an open-branch and a closed-branch. This design can reduce noisy supervision from pseudo boxes. Moreover the two branches learn complementary knowledge from different training data significantly enhancing performance when fused together. Second in our view unlike in closed-set tasks the PL distributions in OVD are solely determined by the teacher model. We introduce a periodic update strategy to decrease the number of updates to the teacher thereby decreasing the frequency of changes in PL distributions which stabilizes the training process. Extensive experiments demonstrate SAS-Det is both efficient and effective. SAS-Det outperforms recent models of the same scale by a clear margin and achieves 37.4 AP50 and 29.1 APr on novel categories of the COCO and LVIS benchmarks respectively. Code is available at https://github.com/xiaofeng94/SAS-Det.
We study the zero-shot Composed Image Retrieval (ZS-CIR) task which is to retrieve the target image given a reference image and a description without training on the triplet datasets. Previous works generate pseudo-word tokens by projecting the reference image features to the text embedding space. However they focus on the global visual representation ignoring the representation of detailed attributes e.g. color object number and layout. To address this challenge we propose a Knowledge-Enhanced Dual-stream zero-shot composed image retrieval framework (KEDs). KEDs implicitly models the attributes of the reference images by incorporating a database. The database enriches the pseudo-word tokens by providing relevant images and captions emphasizing shared attribute information in various aspects. In this way KEDs recognizes the reference image from diverse perspectives. Moreover KEDs adopts an extra stream that aligns pseudo-word tokens with textual concepts leveraging pseudo-triplets mined from image-text pairs. The pseudo-word tokens generated in this stream are explicitly aligned with fine-grained semantics in the text embedding space. Extensive experiments on widely used benchmarks i.e. ImageNet-R COCO object Fashion-IQ and CIRR show that KEDs outperforms previous zero-shot composed image retrieval methods. Code is available at https://github.com/suoych/KEDs.
Distraction is All You Need: Memory-Efficient Image Immunization against Diffusion-Based Image Editing
PDF ↗Recent text-to-image (T2I) diffusion models have revolutionized image editing by empowering users to control outcomes using natural language. However the ease of image manipulation has raised ethical concerns with the potential for malicious use in generating deceptive or harmful content. To address the concerns we propose an image immunization approach named semantic attack to protect our images from being manipulated by malicious agents using diffusion models. Our approach focuses on disrupting the semantic understanding of T2I diffusion models regarding specific content. By attacking the cross-attention mechanism that encodes image features with text messages during editing we distract the model's attention regarding the content of our concern. Our semantic attack renders the model uncertain about the areas to edit resulting in poorly edited images and contradicting the malicious editing attempts. In addition by shifting the attack target towards intermediate attention maps from the final generated image our approach substantially diminishes computational burden and alleviates GPU memory constraints in comparison to previous methods. Moreover we introduce timestep universal gradient updating to create timestep-agnostic perturbations effective across different input noise levels. By treating the full diffusion process as discrete denoising timesteps during the attack we achieve equivalent or even superior immunization efficacy with nearly half the memory consumption of the previous method. Our contributions include a practical and effective approach to safeguard images against malicious editing and the proposed method offers robust immunization against various image inpainting and editing approaches showcasing its potential for real-world applications.
Federated learning achieves effective performance in modeling decentralized data. In practice client data are not well-labeled which makes it potential for federated unsupervised learning (FUSL) with non-IID data. However the performance of existing FUSL methods suffers from insufficient representations i.e. (1) representation collapse entanglement among local and global models and (2) inconsistent representation spaces among local models. The former indicates that representation collapse in local model will subsequently impact the global model and other local models. The latter means that clients model data representation with inconsistent parameters due to the deficiency of supervision signals. In this work we propose FedU2 which enhances generating uniform and unified representation in FUSL with non-IID data. Specifically FedU2 consists of flexible uniform regularizer (FUR) and efficient unified aggregator (EUA). FUR in each client avoids representation collapse via dispersing samples uniformly and EUA in server promotes unified representation by constraining consistent client model updating. To extensively validate the performance of FedU2 we conduct both cross-device and cross-silo evaluation experiments on two benchmark datasets i.e. CIFAR10 and CIFAR100.
Oriented object detection has witnessed significant progress in recent years. However the impressive performance of oriented object detectors is at the huge cost of labor-intensive annotations and deteriorates once the annotated data becomes limited. Semi-supervised learning in which sufficient unannotated data are utilized to enhance the base detector is a promising method to address the annotation deficiency problem. Motivated by weakly supervised learning we introduce annotation-efficient point annotations for unannotated images and propose a weakly semi-supervised method for oriented object detection to balance the detection performance and annotation cost. Specifically we propose a Rotation-Modulated Relational Graph Matching method to match relations of proposals centered on annotated points between different models to alleviate the ambiguity of point annotations in depicting the oriented object. In addition we further propose a Relational Rank Distribution Matching method to align the rank distribution on classification and regression between different models. Finally to handle the difficult annotated points that both models are confused about we introduce weakly supervised learning to impose positive signals for difficult point-induced clusters to the base model and focus the base model on the occupancy between the predictions and annotated points. We perform extensive experiments on challenging datasets to demonstrate the effectiveness of our proposed weakly semi-supervised method in effectively leveraging unannotated data for significant performance improvement.
We introduced StyleEntity a zero-shot image manipulation model that utilizes named entities as proxies during its training phase. This strategy enables our model to manipulate images using unseen textual descriptions during inference all within a single training phase. Additionally we proposed an inference technique termed Prompt Ensemble Latent Averaging (PELA). PELA averages the manipulation directions derived from various named entities during inference effectively eliminating the noise directions thus achieving stable manipulation. In our experiments StyleEntity exhibited superior performance in a zero-shot setting compared to other methods. The code model weights and datasets is available at https://github.com/feng-zhida/StyleEntity.
Simultaneous localization and mapping (SLAM) is a fundamental task for numerous applications such as autonomous navigation and exploration. Despite many SLAM datasets have been released current SLAM solutions still struggle to have sustained and resilient performance. One major issue is the absence of high-quality datasets including diverse all-weather conditions and a reliable metric for assessing robustness. This limitation significantly restricts the scalability and generalizability of SLAM technologies impacting their development validation and deployment. To address this problem we present SubT-MRS an extremely challenging real-world dataset designed to push SLAM towards all-weather environments to pursue the most robust SLAM performance. It contains multi-degraded environments including over 30 diverse scenes such as structureless corridors varying lighting conditions and perceptual obscurants like smoke and dust; multimodal sensors such as LiDAR fisheye camera IMU and thermal camera; and multiple locomotions like aerial legged and wheeled robots. We developed accuracy and robustness evaluation tracks for SLAM and introduced novel robustness metrics. Comprehensive studies are performed revealing new observations challenges and opportunities for future research.