Recently diffusion models have made remarkable progress in text-to-image (T2I) generation synthesizing images with high fidelity and diverse contents. Despite this advancement latent space smoothness within diffusion models remains largely unexplored. Smooth latent spaces ensure that a perturbation on an input latent corresponds to a steady change in the output image. This property proves beneficial in downstream tasks including image interpolation inversion and editing. In this work we expose the non-smoothness of diffusion latent spaces by observing noticeable visual fluctuations resulting from minor latent variations. To tackle this issue we propose Smooth Diffusion a new category of diffusion models that can be simultaneously high-performing and smooth. Specifically we introduce Step-wise Variation Regularization to enforce the proportion between the variations of an arbitrary input latent and that of the output image is a constant at any diffusion training step. In addition we devise an interpolation standard deviation (ISTD) metric to effectively assess the latent space smoothness of a diffusion model. Extensive quantitative and qualitative experiments demonstrate that Smooth Diffusion stands out as a more desirable solution not only in T2I generation but also across various downstream tasks. Smooth Diffusion is implemented as a plug-and-play Smooth-LoRA to work with various community models. Code is available at https://github.com/SHI-Labs/Smooth-Diffusion.
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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.
Summarize the Past to Predict the Future: Natural Language Descriptions of Context Boost Multimodal Object Interaction Anticipation
PDF ↗We study object interaction anticipation in egocentric videos. This task requires an understanding of the spatio-temporal context formed by past actions on objects coined "action context". We propose TransFusion a multimodal transformer-based architecture for short-term object interaction anticipation. Our method exploits the representational power of language by summarizing the action context textually after leveraging pre-trained vision-language foundation models to extract the action context from past video frames. The summarized action context and the last observed video frame are processed by the multimodal fusion module to forecast the next object interaction. Experiments on the Ego4D next active object interaction dataset show the effectiveness of our multimodal fusion model and highlight the benefits of using the power of foundation models and language-based context summaries in a task where vision may appear to suffice. Our novel approach outperforms all state-of-the-art methods on both versions of the Ego4D dataset.
Selectively Informative Description can Reduce Undesired Embedding Entanglements in Text-to-Image Personalization
PDF ↗In text-to-image personalization a timely and crucial challenge is the tendency of generated images overfitting to the biases present in the reference images. We initiate our study with a comprehensive categorization of the biases into background nearby-object tied-object substance (in style re-contextualization) and pose biases. These biases manifest in the generated images due to their entanglement into the subject embedding. This undesired embedding entanglement not only results in the reflection of biases from the reference images into the generated images but also notably diminishes the alignment of the generated images with the given generation prompt. To address this challenge we propose SID (Selectively Informative Description) a text description strategy that deviates from the prevalent approach of only characterizing the subject's class identification. SID is generated utilizing multimodal GPT-4 and can be seamlessly integrated into optimization-based models. We present comprehensive experimental results along with analyses of cross-attention maps subject-alignment non-subject-disentanglement and text-alignment.
Convolutional neural networks benefit from translation equivariance achieving tremendous success. Equivariant networks further extend this property to other transformation groups. However most existing methods require discretization or sampling of groups leading to increased model sizes for larger groups such as the affine group. In this paper we build affine equivariant networks based on differential invariants from the viewpoint of symmetric PDEs without discretizing or sampling the group. To address the division-by-zero issue arising from fractional differential invariants of the affine group we construct a new kind of affine invariants by normalizing polynomial relative differential invariants to replace classical differential invariants. For further flexibility we design an equivariant layer which can be directly integrated into convolutional networks of various architectures. Moreover our framework for the affine group is also applicable to its continuous subgroups. We implement equivariant networks for the scale group the rotation-scale group and the affine group. Numerical experiments demonstrate the outstanding performance of our framework across classification tasks involving transformations of these groups. Remarkably under the out-of-distribution setting our model achieves a 3.37% improvement in accuracy over the main counterpart affConv on the affNIST dataset.
In radio astronomy visibility data which are measurements of wave signals from radio telescopes are transformed into images for observation of distant celestial objects. However these resultant images usually contain both real sources and artifacts due to signal sparsity and other factors. One way to obtain cleaner images is to reconstruct samples into dense forms before imaging. Unfortunately existing reconstruction methods often miss some components of visibility in frequency domain so blurred object edges and persistent artifacts remain in the images. Furthermore the computation overhead is high on irregular visibility samples due to the data skew. To address these problems we propose PolarRec a transformer-encoder-conditioned reconstruction pipeline with visibility samples converted into the polar coordinate system. This coordinate system matches the way in which radio telescopes observe a celestial area as the Earth rotates. As a result visibility samples distribute in the polar system more uniformly than in the Cartesian space. Therefore we propose to use radial distance in the loss function to help reconstruct complete visibility effectively. Also we group visibility samples by their polar angles and propose a group-based encoding scheme to improve the efficiency. Our experiments demonstrate that PolarRec markedly improves imaging results by faithfully reconstructing all frequency components in the visibility domain while significantly reducing the computation cost in visibility data encoding. The code is available at https://github.com/RapidsAtHKUST/PolarRec.
In this paper we revisit techniques for uncertainty estimation within deep neural networks and consolidate a suite of techniques to enhance their reliability. Our investigation reveals that an integrated application of diverse techniques--spanning model regularization classifier and optimization--substantially improves the accuracy of uncertainty predictions in image classification tasks. The synergistic effect of these techniques culminates in our novel SURE approach. We rigorously evaluate SURE against the benchmark of failure prediction a critical testbed for uncertainty estimation efficacy. Our results showcase a consistently better performance than models that individually deploy each technique across various datasets and model architectures. When applied to real-world challenges such as data corruption label noise and long-tailed class distribution SURE exhibits remarkable robustness delivering results that are superior or on par with current state-of-the-art specialized methods. Particularly on Animal-10N and Food-101N for learning with noisy labels SURE achieves state-of-the-art performance without any task-specific adjustments. This work not only sets a new benchmark for robust uncertainty estimation but also paves the way for its application in diverse real-world scenarios where reliability is paramount. Our code is available at https://yutingli0606.github.io/SURE/.
Open3DSG: Open-Vocabulary 3D Scene Graphs from Point Clouds with Queryable Objects and Open-Set Relationships
PDF ↗Current approaches for 3D scene graph prediction rely on labeled datasets to train models for a fixed set of known object classes and relationship categories. We present Open3DSG an alternative approach to learn 3D scene graph prediction in an open world without requiring labeled scene graph data. We co-embed the features from a 3D scene graph prediction backbone with the feature space of powerful open world 2D vision language foundation models. This enables us to predict 3D scene graphs from 3D point clouds in a zero-shot manner by querying object classes from an open vocabulary and predicting the inter-object relationships from a grounded LLM with scene graph features and queried object classes as context. Open3DSG is the first 3D point cloud method to predict not only explicit open-vocabulary object classes but also open-set relationships that are not limited to a predefined label set making it possible to express rare as well as specific objects and relationships in the predicted 3D scene graph. Our experiments show that Open3DSG is effective at predicting arbitrary object classes as well as their complex inter-object relationships describing spatial supportive semantic and comparative relationships.
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.
Learning by Correction: Efficient Tuning Task for Zero-Shot Generative Vision-Language Reasoning
PDF ↗Generative vision-language models (VLMs) have shown impressive performance in zero-shot vision-language tasks like image captioning and visual question answering.However improving their zero-shot reasoning typically requires second-stage instruction tuning which relies heavily on human-labeled or large language model-generated annotation incurring high labeling costs. To tackle this challenge we introduce Image-Conditioned Caption Correction (ICCC) a novel pre-training task designed to enhance VLMs' zero-shot performance without the need for labeled task-aware data. The ICCC task compels VLMs to rectify mismatches between visual and language concepts thereby enhancing instruction following and text generation conditioned on visual inputs. Leveraging language structure and a lightweight dependency parser we construct data samples of ICCC task from image-text datasets with low labeling and computation costs. Experimental results on BLIP-2 and InstructBLIP demonstrate significant improvements in zero-shot image-text generation-based VL tasks through ICCC instruction tuning.
Image datasets are essential not only in validating existing methods in computer vision but also in developing new methods. Many image datasets exist consisting of trichromatic intensity images taken with RGB cameras which are designed to replicate human vision. However polarization and spectrum the wave properties of light that animals in harsh environments and with limited brain capacity often rely on remain underrepresented in existing datasets. Although there are previous spectro-polarimetric datasets they have insufficient object diversity limited illumination conditions linear-only polarization data and inadequate image count. Here we introduce two spectro-polarimetric datasets consisting of trichromatic Stokes images and hyperspectral Stokes images. These datasets encompass both linear and circular polarization; they introduce multiple spectral channels; and they feature a broad selection of real-world scenes. With our dataset in hand we analyze the spectro-polarimetric image statistics develop efficient representations of such high-dimensional data and evaluate spectral dependency of shape-from-polarization methods. As such the proposed dataset promises a foundation for data-driven spectro-polarimetric imaging and vision research.
Multi-modal Large Language Models (MLLMs) have demonstrated impressive instruction abilities across various open-ended tasks. However previous methods have primarily focused on enhancing multi-modal capabilities. In this work we introduce a versatile multi-modal large language model mPLUG-Owl2 which effectively leverages modality collaboration to improve performance in both text and multi-modal tasks. mPLUG-Owl2 utilizes a modularized network design with the language decoder acting as a universal interface for managing different modalities. Specifically mPLUG-Owl2 incorporates shared functional modules to facilitate modality collaboration and introduces a modality-adaptive module that preserves modality-specific features. Extensive experiments reveal that mPLUG-Owl2 is capable of generalizing both text tasks and multi-modal tasks while achieving state-of-the-art performances with a single generalized model. Notably mPLUG-Owl2 is the first MLLM model that demonstrates the modality collaboration phenomenon in both pure-text and multi-modal scenarios setting a pioneering path in the development of future multi-modal foundation models.
With photo-realistic image generation Neural Radiance Field (NeRF) is widely used for large-scale dynamic scene reconstruction as autonomous driving simulator. However large-scale scene reconstruction still suffers from extremely long training time and rendering time. Low-resolution (LR) rendering combined with upsampling can alleviate this problem but it degrades image quality. In this paper we design a lightweight reference decoder which exploits prior information from known views to improve image reconstruction quality of new views. In addition to speed up prior information search we propose an optical flow and structural similarity based prior information search method. Results on KITTI and VKITTI2 datasets show that our method significantly outperforms the baseline method in terms of training speed rendering speed and rendering quality.
We introduce multimodal story summarization by leveraging TV episode recaps - short video sequences interweaving key story moments from previous episodes to bring viewers up to speed. We propose PlotSnap a dataset featuring two crime thriller TV shows with rich recaps and long episodes of 40 minutes. Story summarization labels are unlocked by matching recap shots to corresponding sub-stories in the episode. We propose a hierarchical model TaleSumm that processes entire episodes by creating compact shot and dialog representations and predicts importance scores for each video shot and dialog utterance by enabling interactions between local story groups. Unlike traditional summarization our method extracts multiple plot points from long videos. We present a thorough evaluation on story summarization including promising cross-series generalization. TaleSumm also shows good results on classic video summarization benchmarks.
We study the visual semantic embedding problem for image-text matching. Most existing work utilizes a tailored cross-attention mechanism to perform local alignment across the two image and text modalities. This is computationally expensive even though it is more powerful than the unimodal dual-encoder approach. This work introduces a dual-encoder image-text matching model leveraging a scene graph to represent captions with nodes for objects and attributes interconnected by relational edges. Utilizing a graph attention network our model efficiently encodes object-attribute and object-object semantic relations resulting in a robust and fast-performing system. Representing caption as a scene graph offers the ability to utilize the strong relational inductive bias of graph neural networks to learn object-attribute and object-object relations effectively. To train the model we propose losses that align the image and caption both at the holistic level (image-caption) and the local level (image-object entity) which we show is key to the success of the model. Our model is termed Composition model for Object Relations and Attributes CORA. Experimental results on two prominent image-text retrieval benchmarks Flickr30K and MS-COCO demonstrate that CORA outperforms existing state-of-the-art computationally expensive cross-attention methods regarding recall score while achieving fast computation speed of the dual encoder. Our code is available at https://github.com/vkhoi/cora_cvpr24
SD2Event:Self-supervised Learning of Dynamic Detectors and Contextual Descriptors for Event Cameras
PDF ↗Event cameras offer many advantages over traditional frame-based cameras such as high dynamic range and low latency. Therefore event cameras are widely applied in diverse computer vision applications where event-based keypoint detection is a fundamental task. However achieving robust event-based keypoint detection remains challenging because the ground truth of event keypoints is difficult to obtain descriptors extracted by CNN usually lack discriminative ability in the presence of intense noise and fixed keypoint detectors are limited in detecting varied keypoint patterns. To address these challenges a novel event-based keypoint detection method is proposed by learning dynamic detectors and contextual descriptors in a self-supervised manner (SD2Event) including a contextual feature descriptor learning (CFDL) module and a dynamic keypoint detector learning (DKDL) module. The proposed SD2Event enjoys several merits. First the proposed CFDL module can model long-range contexts efficiently and effectively. Second the DKDL module generates dynamic keypoint detectors which can detect keypoints with diverse patterns across various event streams. Third the proposed self-supervised signals can guide the model's adaptation to event data. Extensive experimental results on three challenging benchmarks show that our proposed method significantly outperforms stateof-the-art event-based keypoint detection methods.
While remarkable progress has been made on supervised skeleton-based action recognition the challenge of zero-shot recognition remains relatively unexplored. In this paper we argue that relying solely on aligning label-level semantics and global skeleton features is insufficient to effectively transfer locally consistent visual knowledge from seen to unseen classes. To address this limitation we introduce Part-aware Unified Representation between Language and Skeleton (PURLS) to explore visual-semantic alignment at both local and global scales. PURLS introduces a new prompting module and a novel partitioning module to generate aligned textual and visual representations across different levels. The former leverages a pre-trained GPT-3 to infer refined descriptions of the global and local (body-part-based and temporal-interval-based) movements from the original action labels. The latter employs an adaptive sampling strategy to group visual features from all body joint movements that are semantically relevant to a given description. Our approach is evaluated on various skeleton/language backbones and three large-scale datasets i.e. NTU-RGB+D 60 NTU-RGB+D 120 and a newly curated dataset Kinetics-skeleton 200. The results showcase the universality and superior performance of PURLS surpassing prior skeleton-based solutions and standard baselines from other domains. The source codes can be accessed at https://github.com/azzh1/PURLS.
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.
Recent advances in personalized image generation have enabled pre-trained text-to-image models to learn new concepts from specific image sets. However these methods often necessitate extensive test-time finetuning for each new concept leading to inefficiencies in both time and scalability. To address this challenge we introduce InstantBooth an innovative approach leveraging existing text-to-image models for instantaneous text-guided image personalization eliminating the need for test-time finetuning. This efficiency is achieved through two primary innovations. Firstly we utilize an image encoder that transforms input images into a global embedding to grasp the general concept. Secondly we integrate new adapter layers into the pre-trained model enhancing its ability to capture intricate identity details while maintaining language coherence. Significantly our model is trained exclusively on text-image pairs without reliance on concept-specific paired images. When benchmarked against existing finetuning-based personalization techniques like DreamBooth and Textual-Inversion InstantBooth not only shows comparable proficiency in aligning language with image maintaining image quality and preserving identity but also boasts a 100-fold increase in processing speed.
Online Continual Learning (CL) solves the problem of learning the ever-emerging new classification tasks from a continuous data stream. Unlike its offline counterpart in online CL the training data can only be seen once. Most existing online CL research regards catastrophic forgetting (i.e. model stability) as almost the only challenge. In this paper we argue that the model's capability to acquire new knowledge (i.e. model plasticity) is another challenge in online CL. While replay-based strategies have been shown to be effective in alleviating catastrophic forgetting there is a notable gap in research attention toward improving model plasticity. To this end we propose Collaborative Continual Learning (CCL) a collaborative learning based strategy to improve the model's capability in acquiring new concepts. Additionally we introduce Distillation Chain (DC) a collaborative learning scheme to boost the training of the models. We adapt CCL-DC to existing representative online CL works. Extensive experiments demonstrate that even if the learners are well-trained with state-of-the-art online CL methods our strategy can still improve model plasticity dramatically and thereby improve the overall performance by a large margin. The source code of our work is available at https://github.com/maorong-wang/CCL-DC.