Humans possess the remarkable skill of Visual Perception the ability to see and understand the seen helping them make sense of the visual world and in turn reason. Multimodal Large Language Models (MLLM) have recently achieved impressive performance on vision-language tasks ranging from visual question-answering and image captioning to visual reasoning and image generation. However when prompted to identify or count (perceive) the entities in a given image existing MLLM systems fail. Working towards developing an accurate MLLM system for perception and reasoning we propose using Versatile vision enCoders (VCoder) as perception eyes for Multimodal LLMs. We feed the VCoder with perception modalities such as segmentation or depth maps improving the MLLM's perception abilities. Secondly we leverage the images from COCO and outputs from off-the-shelf vision perception models to create our COCO Segmentation Text (COST) dataset for training and evaluating MLLMs on the object perception task. Thirdly we introduce metrics to assess the object perception abilities in MLLMs on our COST dataset. Lastly we provide extensive experimental evidence proving the VCoder's improved object-level perception skills over existing Multimodal LLMs including GPT-4V. We open-source our dataset code and models to promote research.
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Advances in neural fields are enabling high-fidelity capture of the shape and appearance of dynamic 3D scenes. However their capabilities lag behind those offered by conventional representations such as 2D videos because of algorithmic challenges and the lack of large-scale multi-view real-world datasets. We address the dataset limitation with DiVa-360 a real-world 360? dynamic visual dataset that contains synchronized high-resolution and long-duration multi-view video sequences of table-scale scenes captured using a customized low-cost system with 53 cameras. It contains 21 object-centric sequences categorized by different motion types 25 intricate hand-object interaction sequences and 8 long-duration sequences for a total of 17.4 M image frames. In addition we provide foreground-background segmentation masks synchronized audio and text descriptions. We benchmark the state-of-the-art dynamic neural field methods on DiVa-360 and provide insights about existing methods and future challenges on long-duration neural field capture.
Improving Training Efficiency of Diffusion Models via Multi-Stage Framework and Tailored Multi-Decoder Architecture
PDF ↗Diffusion models emerging as powerful deep generative tools excel in various applications. They operate through a two-steps process: introducing noise into training samples and then employing a model to convert random noise into new samples (e.g. images). However their remarkable generative performance is hindered by slow training and sampling. This is due to the necessity of tracking extensive forward and reverse diffusion trajectories and employing a large model with numerous parameters across multiple timesteps (i.e. noise levels). To tackle these challenges we present a multi-stage framework inspired by our empirical findings. These observations indicate the advantages of employing distinct parameters tailored to each timestep while retaining universal parameters shared across all time steps. Our approach involves segmenting the time interval into multiple stages where we employ custom multi-decoder U-net architecture that blends time-dependent models with a universally shared encoder. Our framework enables the efficient distribution of computational resources and mitigates inter-stage interference which substantially improves training efficiency. Extensive numerical experiments affirm the effectiveness of our framework showcasing significant training and sampling efficiency enhancements on three state-of-the-art diffusion models including large-scale latent diffusion models. Furthermore our ablation studies illustrate the impact of two important components in our framework: (i) a novel timestep clustering algorithm for stage division and (ii) an innovative multi-decoder U-net architecture seamlessly integrating universal and customized hyperparameters.
Dr.Hair: Reconstructing Scalp-Connected Hair Strands without Pre-Training via Differentiable Rendering of Line Segments
PDF ↗In the film and gaming industries achieving a realistic hair appearance typically involves the use of strands originating from the scalp. However reconstructing these strands from observed surface images of hair presents significant challenges. The difficulty in acquiring Ground Truth (GT) data has led state-of-the-art learning-based methods to rely on pre-training with manually prepared synthetic CG data. This process is not only labor-intensive and costly but also introduces complications due to the domain gap when compared to real-world data. In this study we propose an optimization-based approach that eliminates the need for pre-training. Our method represents hair strands as line segments growing from the scalp and optimizes them using a novel differentiable rendering algorithm. To robustly optimize a substantial number of slender explicit geometries we introduce 3D orientation estimation utilizing global optimization strand initialization based on Laplace's equation and reparameterization that leverages geometric connectivity and spatial proximity. Unlike existing optimization-based methods our method is capable of reconstructing internal hair flow in an absolute direction. Our method exhibits robust and accurate inverse rendering surpassing the quality of existing methods and significantly improving processing speed.
Unsupervised video object segmentation (VOS) aims to detect and segment the most salient object in videos. The primary techniques used in unsupervised VOS are 1) the collaboration of appearance and motion information; and 2) temporal fusion between different frames. This paper proposes two novel prototype-based attention mechanisms inter-modality attention (IMA) and inter-frame attention (IFA) to incorporate these techniques via dense propagation across different modalities and frames. IMA densely integrates context information from different modalities based on a mutual refinement. IFA injects global context of a video to the query frame enabling a full utilization of useful properties from multiple frames. Experimental results on public benchmark datasets demonstrate that our proposed approach outperforms all existing methods by a substantial margin. The proposed two components are also thoroughly validated via ablative study.
Nowadays leveraging 2D images and pre-trained models to guide 3D point cloud feature representation has shown a remarkable potential to boost the performance of 3D fundamental models. While some works rely on additional data such as 2D real-world images and their corresponding camera poses recent studies target at using point cloud exclusively by designing 3D-to-2D projection. However in the indoor scene scenario existing 3D-to-2D projection strategies suffer from severe occlusions and incoherence which fail to contain sufficient information for fine-grained point cloud segmentation task. In this paper we argue that the crux of the matter resides in the basic premise of existing projection strategies that the medium is homogeneous thereby projection rays propagate along straight lines and behind objects are occluded by front ones. Inspired by the phenomenon of mirage where the occluded objects are exposed by distorted light rays due to heterogeneous medium refraction rate we propose MirageRoom by designing parametric mirage projection with heterogeneous medium to obtain series of projected images with various distorted degrees. We further develop a masked reprojection module across 2D and 3D latent space to bridge the gap between pre-trained 2D backbone and 3D point-wise features. Both quantitative and qualitative experimental results on S3DIS and ScanNet V2 demonstrate the effectiveness of our method.
Referring video object segmentation (RVOS) aims to segment the target instance referred by a given text expression in a video clip. The text expression normally contains sophisticated description of the instance's appearance action and relation with others. It is therefore rather difficult for a RVOS model to capture all these attributes correspondingly in the video; in fact the model often favours more on the action- and relation-related visual attributes of the instance. This can end up with partial or even incorrect mask prediction of the target instance. We tackle this problem by taking a subject-centric short text expression from the original long text expression. The short one retains only the appearance-related information of the target instance so that we can use it to focus the model's attention on the instance's appearance. We let the model make joint predictions using both long and short text expressions; and insert a long-short cross-attention module to interact the joint features and a long-short predictions intersection loss to regulate the joint predictions. Besides the improvement on the linguistic part we also introduce a forward-backward visual consistency loss which utilizes optical flows to warp visual features between the annotated frames and their temporal neighbors for consistency. We build our method on top of two state of the art pipelines. Extensive experiments on A2D-Sentences Refer-YouTube-VOS JHMDB-Sentences and Refer-DAVIS17 show impressive improvements of our method. Code is available here.
Vision foundation models have been explored recently to build general-purpose vision systems. However predominant paradigms driven by casting instance-level tasks as an object-word alignment bring heavy cross-modality interaction which is not effective in prompting object detection and visual grounding. Another line of work that focuses on pixel-level tasks often encounters a large annotation gap of things and stuff and suffers from mutual interference between foreground-object and background-class segmentation. In stark contrast to the prevailing methods we present APE a universal visual perception model for aligning and prompting everything all at once in an image to perform diverse tasks i.e. detection segmentation and grounding as an instance-level sentence-object matching paradigm. Specifically APE advances the convergence of detection and grounding by reformulating language-guided grounding as open-vocabulary detection which efficiently scales up model prompting to thousands of category vocabularies and region descriptions while maintaining the effectiveness of cross-modality fusion. To bridge the granularity gap of different pixel-level tasks APE equalizes semantic and panoptic segmentation to proxy instance learning by considering any isolated regions as individual instances. APE aligns vision and language representation on broad data with natural and challenging characteristics all at once without task-specific fine-tuning. The extensive experiments on over 160 datasets demonstrate that with only one-suit of weights APE outperforms (or is on par with) the state-of-the-art models proving that an effective yet universal perception for anything aligning and prompting is indeed feasible. Codes and trained models are released at https://github.com/shenyunhang/APE.
Image denoising is a fundamental task in computer vision. While prevailing deep learning-based supervised and self-supervised methods have excelled in eliminating in-distribution noise their susceptibility to out-of-distribution (OOD) noise remains a significant challenge. The recent emergence of contrastive language-image pre-training (CLIP) model has showcased exceptional capabilities in open-world image recognition and segmentation. Yet the potential for leveraging CLIP to enhance the robustness of low-level tasks remains largely unexplored. This paper uncovers that certain dense features extracted from the frozen ResNet image encoder of CLIP exhibit distortion-invariant and content-related properties which are highly desirable for generalizable denoising. Leveraging these properties we devise an asymmetrical encoder-decoder denoising network which incorporates dense features including the noisy image and its multi-scale features from the frozen ResNet encoder of CLIP into a learnable image decoder to achieve generalizable denoising. The progressive feature augmentation strategy is further proposed to mitigate feature overfitting and improve the robustness of the learnable decoder. Extensive experiments and comparisons conducted across diverse OOD noises including synthetic noise real-world sRGB noise and low-dose CT image noise demonstrate the superior generalization ability of our method.
Automating visual inspection in industrial production lines is essential for increasing product quality across various industries. Anomaly detection (AD) methods serve as robust tools for this purpose. However existing public datasets primarily consist of images without anomalies limiting the practical application of AD methods in production settings. To address this challenge we present (1) the Valeo Anomaly Dataset (VAD) a novel real-world industrial dataset comprising 5000 images including 2000 instances of challenging real defects across more than 20 subclasses. Acknowledging that traditional AD methods struggle with this dataset we introduce (2) Segmentation-based Anomaly Detector (SegAD). First SegAD leverages anomaly maps as well as segmentation maps to compute local statistics. Next SegAD uses these statistics and an optional supervised classifier score as input features for a Boosted Random Forest (BRF) classifier yielding the final anomaly score. Our SegAD achieves state-of-the-art performance on both VAD (+2.1% AUROC) and the VisA dataset (+0.4% AUROC). The code and the models are publicly available.
N:M sparsity has received increasing attention due to its remarkable performance and latency trade-off compared with structured and unstructured sparsity. However existing N:M sparsity methods do not differentiate the relative importance of weights among blocks and leave important weights underappreciated. Besides they directly apply N:M sparsity to the whole network which will cause severe information loss. Thus they are still sub-optimal. In this paper we propose an efficient and effective Multi-Axis Query methodology dubbed as MaxQ to rectify these problems. During the training MaxQ employs a dynamic approach to generate soft N:M masks considering the weight importance across multiple axes. This method enhances the weights with more importance and ensures more effective updates. Meanwhile a sparsity strategy that gradually increases the percentage of N:M weight blocks is applied which allows the network to heal from the pruning-induced damage progressively. During the runtime the N:M soft masks can be precomputed as constants and folded into weights without causing any distortion to the sparse pattern and incurring additional computational overhead. Comprehensive experiments demonstrate that MaxQ achieves consistent improvements across diverse CNN architectures in various computer vision tasks including image classification object detection and instance segmentation. For ResNet50 with 1:16 sparse pattern MaxQ can achieve 74.6% top-1 accuracy on ImageNet and improve by over 2.8% over the state-of-the-art. Codes and checkpoints are available at https://github.com/JingyangXiang/MaxQ.
Public datasets such as KITTI nuScenes and Waymo have played a key role in the research and development of autonomous vehicles and advanced driver assistance systems. However many of these datasets fail to incorporate a full range of driving conditions; some datasets only contain clear-weather conditions underrepresenting or entirely missing colder weather conditions such as snow or autumn scenes with bright colorful foliage. In this paper we present the Michigan State University Four Seasons (MSU-4S) Dataset which contains real-world collections of autonomous vehicle data from varied types of driving scenarios. These scenarios were recorded throughout a full range of seasons and capture clear rainy snowy and fall weather conditions at varying times of day. MSU-4S contains more than 100000 two- and three-dimensional frames for camera lidar and radar data as well as Global Navigation Satellite System (GNSS) wheel speed and steering data all annotated with weather time-of-day and time-of-year. Our data includes cluttered scenes that have large numbers of vehicles and pedestrians; and it also captures industrial scenes busy traffic thoroughfare with traffic lights and numerous signs and scenes with dense foliage. While providing a diverse set of scenes our data incorporate an important feature: virtually every scene and its corresponding lidar camera and radar frames were captured in four different seasons enabling unparalleled object detection analysis and testing of the domain shift problem across weather conditions. In that context we present detailed analyses for 3D and 2D object detection showing a strong domain shift effect among MSU-4S data segments collected across different conditions. MSU-4S will also enable advanced multimodal fusion research including different combinations of camera-lidar-radar fusion which continues to be of strong interest for the computer vision autonomous driving and ADAS development communities. The MSU-4S dataset is available online at https://egr.msu.edu/waves/msu4s.
3D Morphable Models (3DMMs) provide promising 3D face reconstructions in various applications. However existing methods struggle to reconstruct faces with extreme expressions due to deficiencies in supervisory signals such as sparse or inaccurate landmarks. Segmentation information contains effective geometric contexts for face reconstruction. Certain attempts intuitively depend on differentiable renderers to compare the rendered silhouettes of reconstruction with segmentation which is prone to issues like local optima and gradient instability. In this paper we fully utilize the facial part segmentation geometry by introducing Part Re-projection Distance Loss (PRDL). Specifically PRDL transforms facial part segmentation into 2D points and re-projects the reconstruction onto the image plane. Subsequently by introducing grid anchors and computing different statistical distances from these anchors to the point sets PRDL establishes geometry descriptors to optimize the distribution of the point sets for face reconstruction. PRDL exhibits a clear gradient compared to the renderer-based methods and presents state-of-the-art reconstruction performance in extensive quantitative and qualitative experiments. Our project is available at https://github.com/wang-zidu/3DDFA-V3.
Recent methods for label-free 3D semantic segmentation aim to assist 3D model training by leveraging the open-world recognition ability of pre-trained vision language models. However these methods usually suffer from inconsistent and noisy pseudo-labels provided by the vision language models. To address this issue we present a hierarchical intra-modal correlation learning framework that captures visual and geometric correlations in 3D scenes at three levels: intra-set intra-scene and inter-scene to help learn more compact 3D representations. We refine pseudo-labels using intra-set correlations within each geometric consistency set and align features of visually and geometrically similar points using intra-scene and inter-scene correlation learning. We also introduce a feedback mechanism to distill the correlation learning capability into the 3D model. Experiments on both indoor and outdoor datasets show the superiority of our method. We achieve a state-of-the-art 36.6% mIoU on the ScanNet dataset and a 23.0% mIoU on the nuScenes dataset with improvements of 7.8% mIoU and 2.2% mIoU compared with previous SOTA. We also provide theoretical analysis and qualitative visualization results to discuss the mechanism and conduct thorough ablation studies to support the effectiveness of our framework.
Hierarchy is a natural representation of semantic taxonomies including the ones routinely used in image segmentation. Indeed recent work on semantic segmentation reports improved accuracy from supervised training leveraging hierarchical label structures. Encouraged by these results we revisit the fundamental assumptions behind that work. We postulate and then empirically verify that the reasons for the observed improvement in segmentation accuracy may be entirely unrelated to the use of the semantic hierarchy. To demonstrate this we design a range of cross-domain experiments with a representative hierarchical approach. We find that on the new testing domains a flat (non-hierarchical) segmentation network in which the parents are inferred from the children has superior segmentation accuracy to the hierarchical approach across the board. Complementing these findings and inspired by the intrinsic properties of hyperbolic spaces we study a more principled approach to hierarchical segmentation using the Poincare ball model. The hyperbolic representation largely outperforms the previous (Euclidean) hierarchical approach as well and is on par with our flat Euclidean baseline in terms of segmentation accuracy. However it additionally exhibits surprisingly strong calibration quality of the parent nodes in the semantic hierarchy especially on the more challenging domains. Our combined analysis suggests that the established practice of hierarchical segmentation may be limited to in-domain settings whereas flat classifiers generalize substantially better especially if they are modeled in the hyperbolic space.
SeaBird: Segmentation in Bird's View with Dice Loss Improves Monocular 3D Detection of Large Objects
PDF ↗Monocular 3D detectors achieve remarkable performance on cars and smaller objects. However their performance drops on larger objects leading to fatal accidents. Some attribute the failures to training data scarcity or the receptive field requirements of large objects. In this paper we highlight this understudied problem of generalization to large objects. We find that modern frontal detectors struggle to generalize to large objects even on nearly balanced datasets. We argue that the cause of failure is the sensitivity of depth regression losses to noise of larger objects. To bridge this gap we comprehensively investigate regression and dice losses examining their robustness under varying error levels and object sizes. We mathematically prove that the dice loss leads to superior noise-robustness and model convergence for large objects compared to regression losses for a simplified case. Leveraging our theoretical insights we propose SeaBird (Segmentation in Bird's View) as the first step towards generalizing to large objects. SeaBird effectively integrates BEV segmentation on foreground objects for 3D detection with the segmentation head trained with the dice loss. SeaBird achieves SoTA results on the KITTI-360 leaderboard and improves existing detectors on the nuScenes leaderboard particularly for large objects.
Recently some large kernel convnets strike back with appealing performance and efficiency. However given the square complexity of convolution scaling up kernels can bring about an enormous amount of parameters and the proliferated parameters can induce severe optimization problem. Due to these issues current CNNs compromise to scale up to 51x51 in the form of stripe convolution (i.e. 51x5+5x51) and start to saturate as the kernel size continues growing. In this paper we delve into addressing these vital issues and explore whether we can continue scaling up kernels for more performance gains. Inspired by human vision we propose a human-like peripheral convolution that efficiently reduces over 90% parameter count of dense grid convolution through parameter sharing and manage to scale up kernel size to extremely large. Our peripheral convolution behaves highly similar to human reducing the complexity of convolution from O(K^2) to O(logK) without backfiring performance. Built on this we propose Parameter-efficient Large Kernel Network (PeLK). Our PeLK outperforms modern vision Transformers and ConvNet architectures like Swin ConvNeXt RepLKNet and SLaK on various vision tasks including ImageNet classification semantic segmentation on ADE20K and object detection on MS COCO. For the first time we successfully scale up the kernel size of CNNs to an unprecedented 101x101 and demonstrate consistent improvements.
Few-shot semantic segmentation (FSS) endeavors to segment unseen classes with only a few labeled samples. Current FSS methods are commonly built on the assumption that their training and application scenarios share similar domains and their performances degrade significantly while applied to a distinct domain. To this end we propose to leverage the cutting-edge foundation model the Segment Anything Model (SAM) for generalization enhancement. The SAM however performs unsatisfactorily on domains that are distinct from its training data which primarily comprise natural scene images and it does not support automatic segmentation of specific semantics due to its interactive prompting mechanism. In our work we introduce APSeg a novel auto-prompt network for cross-domain few-shot semantic segmentation (CD-FSS) which is designed to be auto-prompted for guiding cross-domain segmentation. Specifically we propose a Dual Prototype Anchor Transformation (DPAT) module that fuses pseudo query prototypes extracted based on cycle-consistency with support prototypes allowing features to be transformed into a more stable domain-agnostic space. Additionally a Meta Prompt (MPG) module is introduced to automatically generate prompt embeddings eliminating the need for manual visual prompts. We build an efficient model which can be applied directly to target domains without fine-tuning. Extensive experiments on four cross-domain datasets show that our model outperforms the state-of-the-art CD-FSS method by 5.24% and 3.10% in average accuracy on 1-shot and 5-shot settings respectively.
With recent video object segmentation (VOS) benchmarks evolving to challenging scenarios we revisit a simple but overlooked strategy: restricting the size of memory banks. This diverges from the prevalent practice of expanding memory banks to accommodate extensive historical information. Our specially designed "memory deciphering" study offers a pivotal insight underpinning such a strategy: expanding memory banks while seemingly beneficial actually increases the difficulty for VOS modules to decode relevant features due to the confusion from redundant information. By restricting memory banks to a limited number of essential frames we achieve a notable improvement in VOS accuracy. This process balances the importance and freshness of frames to maintain an informative memory bank within a bounded capacity. Additionally restricted memory banks reduce the training-inference discrepancy in memory lengths compared with continuous expansion. This fosters new opportunities in temporal reasoning and enables us to introduce the previously overlooked "temporal positional embedding." Finally our insights are embodied in "RMem" ("R" for restricted) a simple yet effective VOS modification that excels at challenging VOS scenarios and establishes new state of the art for object state changes (VOST dataset) and long videos (the Long Videos dataset). Our codes are available at https://github.com/Restricted-Memory/RMemand our demo can be watched on https://youtu.be/V3tCFQsJrrM.
Zero-shot Video Object Segmentation (ZSVOS) aims at segmenting the primary moving object without any human annotations. Mainstream solutions mainly focus on learning a single model on large-scale video datasets which struggle to generalize to unseen videos. In this work we introduce a test-time training (TTT) strategy to address the problem. Our key insight is to enforce the model to predict consistent depth during the TTT process. In detail we first train a single network to perform both segmentation and depth prediction tasks. This can be effectively learned with our specifically designed depth modulation layer. Then for the TTT process the model is updated by predicting consistent depth maps for the same frame under different data augmentations. In addition we explore different TTT weight update strategies. Our empirical results suggest that the momentum-based weight initialization and looping-based training scheme lead to more stable improvements. Experiments show that the proposed method achieves clear improvements on ZSVOS. Our proposed video TTT strategy provides significant superiority over state-of-the-art TTT methods. Our code is available at: https://nifangbaage.github.io/DATTT/.