CVPR 2024 Papers

The landscape of deep learning research is moving towards innovative strategies to harness the true potential of data. Traditionally emphasis has been on scaling model architectures resulting in large and complex neural networks which can be difficult to train with limited computational resources. However independently of the model size data quality (i.e. amount and variability) is still a major factor that affects model generalization. In this work we propose a novel technique to exploit available data through the use of automatic data augmentation for the tasks of image classification and semantic segmentation. We introduce the first Differentiable Augmentation Search method (DAS) to generate variations of images that can be processed as videos. Compared to previous approaches DAS is extremely fast and flexible allowing the search on very large search spaces in less than a GPU day. Our intuition is that the increased receptive field in the temporal dimension provided by DAS could lead to benefits also to the spatial receptive field. More specifically we leverage DAS to guide the reshaping of the spatial receptive field by selecting task-dependant transformations. As a result compared to standard augmentation alternatives we improve in terms of accuracy on ImageNet Cifar10 Cifar100 Tiny-ImageNet Pascal-VOC-2012 and CityScapes datasets when plugging-in our DAS over different light-weight video backbones.

Two primary input modalities prevail in image retrieval: sketch and text. While text is widely used for inter-category retrieval tasks sketches have been established as the sole preferred modality for fine-grained image retrieval due to their ability to capture intricate visual details. In this paper we question the reliance on sketches alone for fine-grained image retrieval by simultaneously exploring the fine-grained representation capabilities of both sketch and text orchestrating a duet between the two. The end result enables precise retrievals previously unattainable allowing users to pose ever-finer queries and incorporate attributes like colour and contextual cues from text. For this purpose we introduce a novel compositionality framework effectively combining sketches and text using pre-trained CLIP models while eliminating the need for extensive fine-grained textual descriptions. Last but not least our system extends to novel applications in composed image retrieval domain attribute transfer and fine-grained generation providing solutions for various real-world scenarios.

The advent of Vision Transformers (ViTs) marks a substantial paradigm shift in the realm of computer vision. ViTs capture the global information of images through self-attention modules which perform dot product computations among patchified image tokens. While self-attention modules empower ViTs to capture long-range dependencies the computational complexity grows quadratically with the number of tokens which is a major hindrance to the practical application of ViTs. Moreover the self-attention mechanism in deep ViTs is also susceptible to the attention saturation issue. Accordingly we argue against the necessity of computing the attention scores in every layer and we propose the Less-Attention Vision Transformer (LaViT) which computes only a few attention operations at each stage and calculates the subsequent feature alignments in other layers via attention transformations that leverage the previously calculated attention scores. This novel approach can mitigate two primary issues plaguing traditional self-attention modules: the heavy computational burden and attention saturation. Our proposed architecture offers superior efficiency and ease of implementation merely requiring matrix multiplications that are highly optimized in contemporary deep learning frameworks. Moreover our architecture demonstrates exceptional performance across various vision tasks including classification detection and segmentation.

Out-of-distribution (OOD) detection has attracted a large amount of attention from the machine learning research community in recent years due to its importance in deployed systems. Most of the previous studies focused on the detection of OOD samples in the multi-class classification task. However OOD detection in the multi-label classification task a more common real-world use case remains an underexplored domain. In this research we propose YolOOD - a method that utilizes concepts from the object detection domain to perform OOD detection in the multi-label classification task. Object detection models have an inherent ability to distinguish between objects of interest (in-distribution data) and irrelevant objects (OOD data) in images that contain multiple objects belonging to different class categories. These abilities allow us to convert a regular object detection model into an image classifier with inherent OOD detection capabilities with just minor changes. We compare our approach to state-of-the-art OOD detection methods and demonstrate YolOOD's ability to outperform these methods on a comprehensive suite of in-distribution and OOD benchmark datasets.

The You Only Look Once (YOLO) series of detectors have established themselves as efficient and practical tools. However their reliance on predefined and trained object categories limits their applicability in open scenarios. Addressing this limitation we introduce YOLO-World an innovative approach that enhances YOLO with open-vocabulary detection capabilities through vision-language modeling and pre-training on large-scale datasets. Specifically we propose a new Re-parameterizable Vision-Language Path Aggregation Network (RepVL-PAN) and region-text contrastive loss to facilitate the interaction between visual and linguistic information. Our method excels in detecting a wide range of objects in a zero-shot manner with high efficiency. On the challenging LVIS dataset YOLO-World achieves 35.4 AP with 52.0 FPS on V100 which outperforms many state-of-the-art methods in terms of both accuracy and speed. Furthermore the fine-tuned YOLO-World achieves remarkable performance on several downstream tasks including object detection and open-vocabulary instance segmentation. Code and models are available at https://github.com/AILab-CVC/YOLO-World

We propose XScale-NVS for high-fidelity cross-scale novel view synthesis of real-world large-scale scenes. Existing representations based on explicit surface suffer from discretization resolution or UV distortion while implicit volumetric representations lack scalability for large scenes due to the dispersed weight distribution and surface ambiguity. In light of the above challenges we introduce hash featurized manifold a novel hash-based featurization coupled with a deferred neural rendering framework. This approach fully unlocks the expressivity of the representation by explicitly concentrating the hash entries on the 2D manifold thus effectively representing highly detailed contents independent of the discretization resolution. We also introduce a novel dataset namely GigaNVS to benchmark cross-scale high-resolution novel view synthesis of real-world large-scale scenes. Our method significantly outperforms competing baselines on various real-world scenes yielding an average LPIPS that is ?40% lower than prior state-of-the-art on the challenging GigaNVS benchmark. Please see our project page at: xscalenvs.github.io.

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) has caused public concern in recent years. The high prevalence and risk of severe complications make monitoring NAFLD progression a public health priority. Fibrosis staging from liver biopsy images plays a key role in demonstrating the histological progression of NAFLD. Fibrosis mainly involves the deposition of fibers around vessels. Current deep learning-based fibrosis staging methods learn spatial relationships between tissue patches but do not explicitly consider the relationships between vessels and fibers leading to limited performance and poor interpretability. In this paper we propose an eXplicit vessel-fiber modeling method for Fibrosis staging from liver biopsy images namely XFibrosis. Specifically we transform vessels and fibers into graph-structured representations where their micro-structures are depicted by vessel-induced primal graphs and fiber-induced dual graphs respectively. Moreover the fiber-induced dual graphs also represent the connectivity information between vessels caused by fiber deposition. A primal-dual graph convolution module is designed to facilitate the learning of spatial relationships between vessels and fibers allowing for the joint exploration and interaction of their micro-structures. Experiments conducted on two datasets have shown that explicitly modeling the relationship between vessels and fibers leads to improved fibrosis staging and enhanced interpretability.

We introduce a lightweight and accurate architecture for resource-efficient visual correspondence. Our method dubbed XFeat (Accelerated Features) revisits fundamental design choices in convolutional neural networks for detecting extracting and matching local features. Our new model satisfies a critical need for fast and robust algorithms suitable to resource-limited devices. In particular accurate image matching requires sufficiently large image resolutions -- for this reason we keep the resolution as large as possible while limiting the number of channels in the network. Besides our model is designed to offer the choice of matching at the sparse or semi-dense levels each of which may be more suitable for different downstream applications such as visual navigation and augmented reality. Our model is the first to offer semi-dense matching efficiently leveraging a novel match refinement module that relies on coarse local descriptors. XFeat is versatile and hardware-independent surpassing current deep learning-based local features in speed (up to 5x faster) with comparable or better accuracy proven in pose estimation and visual localization. We showcase it running in real-time on an inexpensive laptop CPU without specialized hardware optimizations. Code and weights are available at verlab.dcc.ufmg.br/descriptors/xfeat_cvpr24.

We present XCube a novel generative model for high-resolution sparse 3D voxel grids with arbitrary attributes. Our model can generate millions of voxels with a finest effective resolution of up to 1024^3 in a feed-forward fashion without time-consuming test-time optimization. To achieve this we employ a hierarchical voxel latent diffusion model which generates progressively higher resolution grids in a coarse-to-fine manner using a custom framework built on the highly efficient VDB data structure. Apart from generating high-resolution objects we demonstrate the effectiveness of XCube on large outdoor scenes at scales of 100m x 100m with a voxel size as small as 10cm. We observe clear qualitative and quantitative improvements over past approaches. In addition to unconditional generation we show that our model can be used to solve a variety of tasks such as user-guided editing scene completion from a single scan and text-to-3D.

Lately there has been growing interest in adapting vision-language models (VLMs) to image and third-person video classification due to their success in zero-shot recognition. However the adaptation of these models to egocentric videos has been largely unexplored. To address this gap we propose a simple yet effective cross-modal adaptation framework which we call X-MIC. Using a video adapter our pipeline learns to align frozen text embeddings to each egocentric video directly in the shared embedding space. Our novel adapter architecture retains and improves generalization of the pre-trained VLMs by disentangling learnable temporal modeling and frozen visual encoder. This results in an enhanced alignment of text embeddings to each egocentric video leading to a significant improvement in cross-dataset generalization. We evaluate our approach on the Epic-Kitchens Ego4D and EGTEA datasets for fine-grained cross-dataset action generalization demonstrating the effectiveness of our method.

We introduce X-Adapter a universal upgrader to enable the pretrained plug-and-play modules (e.g. ControlNet LoRA) to work directly with the upgraded text-to-image diffusion model (e.g. SDXL) without further retraining. We achieve this goal by training an additional network to control the frozen upgraded model with the new text-image data pairs. In detail X-Adapter keeps a frozen copy of the old model to preserve the connectors of different plugins. Additionally X-Adapter adds trainable mapping layers that bridge the decoders from models of different versions for feature remapping. The remapped features will be used as guidance for the upgraded model. To enhance the guidance ability of X-Adapter we employ a -text training strategy for the upgraded model. After training we also introduce a two-stage denoising strategy to align the initial latents of X-Adapter and the upgraded model. Thanks to our strategies X-Adapter demonstrates universal compatibility with various plugins and also enables plugins of different versions to work together thereby expanding the functionalities of diffusion community. To verify the effectiveness of the proposed method we conduct extensive experiments and the results show that X-Adapter may facilitate wider application in the upgraded foundational diffusion model. Project page at: https://showlab.github.io/X-Adapter.

Numerous prior studies predominantly emphasize constructing relation vectors for individual neighborhood points and generating dynamic kernels for each vector and embedding these into high-dimensional spaces to capture implicit local structures. However we contend that such implicit high-dimensional structure modeling approch inadequately represents the local geometric structure of point clouds due to the absence of explicit structural information. Hence we introduce X-3D an explicit 3D structure modeling approach. X-3D functions by capturing the explicit local structural information within the input 3D space and employing it to produce dynamic kernels with shared weights for all neighborhood points within the current local region. This modeling approach introduces effective geometric prior and significantly diminishes the disparity between the local structure of the embedding space and the original input point cloud thereby improving the extraction of local features. Experiments show that our method can be used on a variety of methods and achieves state-of-the-art performance on segmentation classification detection tasks with lower extra computational cost. Such as 90.7% on ScanObjectNN for classification 79.2% on S3DIS 6 fold and 74.3% on S3DIS Area 5 for segmentation 76.3% on ScanNetV2 for segmentation and 64.5% mAP_ 25 46.9% mAP_ 50 on SUN RGB-D and 69.0% mAP_ 25 51.1% mAP_ 50 on ScanNetV2 . Our code is available at \href https://github.com/sunshuofeng/X-3D https://github.com/sunshuofeng/X-3D .

We investigate the impact of deep generative models on potential social biases in upcoming computer vision models. As the internet witnesses an increasing influx of AI-generated images concerns arise regarding inherent biases that may accompany them potentially leading to the dissemination of harmful content. This paper explores whether a detrimental feedback loop resulting in bias amplification would occur if generated images were used as the training data for future models. We conduct simulations by progressively substituting original images in COCO and CC3M datasets with images generated through Stable Diffusion. The modified datasets are used to train OpenCLIP and image captioning models which we evaluate in terms of quality and bias. Contrary to expectations our findings indicate that introducing generated images during training does not uniformly amplify bias. Instead instances of bias mitigation across specific tasks are observed. We further explore the factors that may influence these phenomena such as artifacts in image generation (e.g. blurry faces) or pre-existing biases in the original datasets.

Three-dimensional (3D) reconstruction from a single image is an ill-posed problem with inherent ambiguities i.e. scale. Predicting a 3D scene from text description(s) is similarly ill-posed i.e. spatial arrangements of objects described. We investigate the question of whether two inherently ambiguous modalities can be used in conjunction to produce metric-scaled reconstructions. To test this we focus on monocular depth estimation the problem of predicting a dense depth map from a single image but with an additional text caption describing the scene. To this end we begin by encoding the text caption as a mean and standard deviation; using a variational framework we learn the distribution of the plausible metric reconstructions of 3D scenes corresponding to the text captions as a prior. To "select" a specific reconstruction or depth map we encode the given image through a conditional sampler that samples from the latent space of the variational text encoder which is then decoded to the output depth map. Our approach is trained alternatingly between the text and image branches: in one optimization step we predict the mean and standard deviation from the text description and sample from a standard Gaussian and in the other we sample using a (image) conditional sampler. Once trained we directly predict depth from the encoded text using the conditional sampler. We demonstrate our approach on indoor (NYUv2) and outdoor (KITTI) scenarios where we show that language can consistently improve performance in both. Code: https://github.com/Adonis-galaxy/WorDepth.

We introduce WonderJourney a modular framework for perpetual 3D scene generation. Unlike prior work on view generation that focuses on a single type of scenes we start at any user-provided location (by a text description or an image) and generate a journey through a long sequence of diverse yet coherently connected 3D scenes. We leverage an LLM to generate textual descriptions of the scenes in this journey a text-driven point cloud generation pipeline to make a compelling and coherent sequence of 3D scenes and a large VLM to verify the generated scenes. We show compelling diverse visual results across various scene types and styles forming imaginary "wonderjourneys". Project website: https://kovenyu.com/WonderJourney.

In this work we introduce Wonder3D a novel method for generating high-fidelity textured meshes from single-view images with remarkable efficiency. Recent methods based on the Score Distillation Sampling (SDS) loss methods have shown the potential to recover 3D geometry from 2D diffusion priors but they typically suffer from time-consuming per-shape optimization and inconsistent geometry. In contrast certain works directly produce 3D information via fast network inferences but their results are often of low quality and lack geometric details. To holistically improve the quality consistency and efficiency of image-to-3D tasks we propose a cross-domain diffusion model that generates multi-view normal maps and the corresponding color images. To ensure consistency we employ a multi-view cross-domain attention mechanism that facilitates information exchange across views and modalities. Lastly we introduce a geometry-aware normal fusion algorithm that extracts high-quality surfaces from the multi-view 2D representations in only 2 3 minutes. Our extensive evaluations demonstrate that our method achieves high-quality reconstruction results robust generalization and remarkable efficiency compared to prior works.

Creating multi-view wire art (MVWA) a static 3D sculpture with diverse interpretations from different viewpoints is a complex task even for skilled artists. In response we present DreamWire an AI system enabling everyone to craft MVWA easily. Users express their vision through text prompts or scribbles freeing them from intricate 3D wire organisation. Our approach synergises 3D Bezier curves Prim's algorithm and knowledge distillation from diffusion models or their variants (e.g. ControlNet). This blend enables the system to represent 3D wire art ensuring spatial continuity and overcoming data scarcity. Extensive evaluation and analysis are conducted to shed insight on the inner workings of the proposed system including the trade-off between connectivity and visual aesthetics.

We present WinSyn a unique dataset and testbed for creating high-quality synthetic data with procedural modeling techniques. The dataset contains high-resolution photographs of windows selected from locations around the world with 89318 individual window crops showcasing diverse geometric and material characteristics. We evaluate a procedural model by training semantic segmentation networks on both synthetic and real images and then comparing their performances on a shared test set of real images. Specifically we measure the difference in mean Intersection over Union (mIoU) and determine the effective number of real images to match synthetic data's training performance. We design a baseline procedural model as a benchmark and provide 21290 synthetically generated images. By tuning the procedural model key factors are identified which significantly influence the model's fidelity in replicating real-world scenarios. Importantly we highlight the challenge of procedural modeling using current techniques especially in their ability to replicate the spatial semantics of real-world scenarios. This insight is critical because of the potential of procedural models to bridge hidden scene aspects such as depth reflectivity material properties and lighting conditions.

We introduce WildlifeMapper (WM) a flexible model designed to detect locate and identify multiple species in aerial imagery. It addresses the limitations of traditional labor-intensive wildlife population assessments that are central to advancing environmental conservation efforts worldwide. While a number of methods exist to automate this process they are often limited in their ability to generalize to different species or landscapes due to the dominance of homogeneous backgrounds and/or poorly captured local image structures. WM introduces two novel modules that help to capture the local structure and context of objects of interest to accurately localize and identify them achieving a state-of-the-art (SOTA) detection rate of 0.56 mAP. Further we introduce a large aerial imagery dataset with more than 11k Images and 28k annotations verified by trained experts. WM also achieves SOTA performance on 3 other publicly available aerial survey datasets collected across 4 different countries improving mAP by 42%. Source code and trained models are available at Github