CVPR 2024 Papers

Gestures play a key role in human communication. Recent methods for co-speech gesture generation while managing to generate beat-aligned motions struggle generating gestures that are semantically aligned with the utterance. Compared to beat gestures that align naturally to the audio signal semantically coherent gestures require modeling the complex interactions between the language and human motion and can be controlled by focusing on certain words. Therefore we present ConvoFusion a diffusion-based approach for multi-modal gesture synthesis which can not only generate gestures based on multi-modal speech inputs but can also facilitate controllability in gesture synthesis. Our method proposes two guidance objectives that allow the users to modulate the impact of different conditioning modalities (e.g. audio vs text) as well as to choose certain words to be emphasized during gesturing. Our method is versatile in that it can be trained either for generating monologue gestures or even the conversational gestures. To further advance the research on multi-party interactive gestures the DnD Group Gesture dataset is released which contains 6 hours of gesture data showing 5 people interacting with one another. We compare our method with several recent works and demonstrate effectiveness of our method on a variety of tasks. We urge the reader to watch our supplementary video at https://vcai.mpi-inf.mpg.de/projects/ConvoFusion/.

Manually creating 3D environments for AR/VR applications is a complex process requiring expert knowledge in 3D modeling software. Pioneering works facilitate this process by generating room meshes conditioned on textual style descriptions. Yet many of these automatically generated 3D meshes do not adhere to typical room layouts compromising their plausibility e.g. by placing several beds in one bedroom. To address these challenges we present ControlRoom3D a novel method to generate high-quality room meshes. Central to our approach is a user-defined 3D semantic proxy room that outlines a rough room layout based on semantic bounding boxes and a textual description of the overall room style. Our key insight is that when rendered to 2D this 3D representation provides valuable geometric and semantic information to control powerful 2D models to generate 3D consistent textures and geometry that aligns well with the proxy room. Backed up by an extensive study including quantitative metrics and qualitative user evaluations our method generates diverse and globally plausible 3D room meshes thus empowering users to design 3D rooms effortlessly without specialized knowledge.

We introduce Control4D an innovative framework for editing dynamic 4D portraits using text instructions. Our method addresses the prevalent challenges in 4D editing notably the inefficiencies of existing 4D representations and the inconsistent editing effect caused by diffusion-based editors. We first propose GaussianPlanes a novel 4D representation that makes Gaussian Splatting more structured by applying plane-based decomposition in 3D space and time. This enhances both efficiency and robustness in 4D editing. Furthermore we propose to leverage a 4D generator to learn a more continuous generation space from inconsistent edited images produced by the diffusion-based editor which effectively improves the consistency and quality of 4D editing. Comprehensive evaluation demonstrates the superiority of Control4D including significantly reduced training time high-quality rendering and spatial-temporal consistency in 4D portrait editing.

No-reference point cloud quality assessment (NR-PCQA) aims to automatically evaluate the perceptual quality of distorted point clouds without available reference which have achieved tremendous improvements due to the utilization of deep neural networks. However learning-based NR-PCQA methods suffer from the scarcity of labeled data and usually perform suboptimally in terms of generalization. To solve the problem we propose a novel contrastive pre-training framework tailored for PCQA (CoPA) which enables the pre-trained model to learn quality-aware representations from unlabeled data. To obtain anchors in the representation space we project point clouds with different distortions into images and randomly mix their local patches to form mixed images with multiple distortions. Utilizing the generated anchors we constrain the pre-training process via a quality-aware contrastive loss following the philosophy that perceptual quality is closely related to both content and distortion. Furthermore in the model fine-tuning stage we propose a semantic-guided multi-view fusion module to effectively integrate the features of projected images from multiple perspectives. Extensive experiments show that our method outperforms the state-of-the-art PCQA methods on popular benchmarks. Further investigations demonstrate that CoPA can also benefit existing learning-based PCQA models.

We address the problem of generalized category discovery (GCD) that aims to partition a partially labeled collection of images; only a small part of the collection is labeled and the total number of target classes is unknown. To address this generalized image clustering problem we revisit the mean-shift algorithm i.e. a classic powerful technique for mode seeking and incorporate it into a contrastive learning framework. The proposed method dubbed Contrastive Mean-Shift (CMS) learning trains an embedding network to produce representations with better clustering properties by an iterative process of mean shift and contrastive update. Experiments demonstrate that our method both in settings with and without the total number of clusters being known achieves state-of-the-art performance on six public GCD benchmarks without bells and whistles.

We propose a unified approach to simultaneously addressing the conventional setting of binary deepfake classification and a more challenging scenario of uncovering what facial components have been forged as well as the exact order of the manipulations. To solve the former task we consider multiple instance learning (MIL) that takes each image as a bag and its patches as instances. A positive bag corresponds to a forged image that includes at least one manipulated patch (i.e. a pixel in the feature map). The formulation allows us to estimate the probability of an input image being a fake one and establish the corresponding contrastive MIL loss. On the other hand tackling the component-wise deepfake problem can be reduced to solving multi-label prediction but the requirement to recover the manipulation order further complicates the learning task into a multi-label ranking problem. We resolve this difficulty by designing a tailor-made loss term to enforce that the rank order of the predicted multi-label probabilities respects the ground-truth order of the sequential modifications of a deepfake image. Through extensive experiments and comparisons with other relevant techniques we provide extensive results and ablation studies to demonstrate that the proposed method is an overall more comprehensive solution to deepfake detection.

With the remarkable advent of text-to-image diffusion models image editing methods have become more diverse and continue to evolve. A promising recent approach in this realm is Delta Denoising Score (DDS) - an image editing technique based on Score Distillation Sampling (SDS) framework that leverages the rich generative prior of text-to-image diffusion models. However relying solely on the difference between scoring functions is insufficient for preserving specific structural elements from the original image a crucial aspect of image editing. To address this here we present an embarrassingly simple yet very powerful modification of DDS called Contrastive Denoising Score (CDS) for latent diffusion models (LDM). Inspired by the similarities and differences between DDS and the contrastive learning for unpaired image-to-image translation(CUT) we introduce a straightforward approach using CUT loss within the DDS framework. Rather than employing auxiliary networks as in the original CUT approach we leverage the intermediate features of LDM specifically those from the self-attention layers which possesses rich spatial information. Our approach enables zero-shot image-to-image translation and neural radiance field (NeRF) editing achieving structural correspondence between the input and output while maintaining content controllability. Qualitative results and comparisons demonstrates the effectiveness of our proposed method.

Vision-Language Models (VLMs) such as CLIP exhibit strong image-text comprehension abilities facilitating advances in several downstream tasks such as zero-shot image classification image-text retrieval and text-to-image generation. However the compositional reasoning abilities of existing VLMs remains subpar. The root of this limitation lies in the inadequate alignment between the images and captions in the pretraining datasets. Additionally the current contrastive learning objective fails to focus on fine-grained grounding components like relations actions and attributes resulting in "bag-of-words" representations. We introduce a simple and effective method to improve compositional reasoning in VLMs. Our method better leverages available datasets by refining and expanding the standard image-text contrastive learning framework. Our approach does not require specific annotations and does not incur extra parameters. When integrated with CLIP our technique yields notable improvement over state-of-the-art baselines across five vision-language compositional benchmarks.

In this paper we showcase the effectiveness of optimizing monocular camera poses as a continuous function of time. The camera poses are represented using an implicit neural function which maps the given time to the corresponding camera pose. The mapped camera poses are then used for the downstream tasks where joint camera pose optimization is also required. While doing so the network parameters - that implicitly represent camera poses - are optimized. We exploit the proposed method in four diverse experimental settings namely (1) NeRF from noisy poses; (2) NeRF from asynchronous Events; (3) Visual Simultaneous Localization and Mapping (vSLAM); and (4) vSLAM with IMUs. In all four settings the proposed method performs significantly better than the compared baselines and the state-of-the-art methods. Additionally using the assumption of continuous motion changes in pose may actually live in a manifold that has lower than 6 degrees of freedom (DOF) is also realized. We call this low DOF motion representation as the intrinsic motion and use the approach in vSLAM settings show ing impressive camera tracking performance.

Most current arbitrary-scale image super-resolution (SR) methods has commonly relied on simulated data generated by simple synthetic degradation models (e.g. bicubic downsampling) at continuous various scales thereby falling short in capturing the complex degradation of real-world images. This limitation hinders the visual quality of these methods when applied to real-world images. To address this issue we propose the Continuous Optical Zooming dataset (COZ) by constructing an automatic imaging system to collect images at fine-grained various focal lengths within a specific range and providing strict image pair alignment. The COZ dataset serves as a benchmark to provide real-world data for training and testing arbitrary-scale SR models. To enhance the model's robustness against real-world image degradation we propose a Local Mix Implicit network (LMI) based on the MLP-mixer architecture and meta-learning which directly learns the local texture information by simultaneously mixing features and coordinates of multiple independent points. The extensive experiments demonstrate the superior performance of the arbitrary-scale SR models trained on the COZ dataset compared to models trained on simulated data. Our LMI model exhibits the superior effectiveness compared to other models. This study is of great significance in developing more efficient algorithms and improving the performance of arbitrary-scale image SR methods in practical applications. Our dataset and codes are available at https://github.com/pf0607/COZ.

Continual Test-Time Adaptation (CTTA) is proposed to migrate a source pre-trained model to continually changing target distributions addressing real-world dynamism. Existing CTTA methods mainly rely on entropy minimization or teacher-student pseudo-labeling schemes for knowledge extraction in unlabeled target domains. However dynamic data distributions cause miscalibrated predictions and noisy pseudo-labels in existing self-supervised learning methods hindering the effective mitigation of error accumulation and catastrophic forgetting problems during the continual adaptation process. To tackle these issues we propose a continual self-supervised method Adaptive Distribution Masked Autoencoders (ADMA) which enhances the extraction of target domain knowledge while mitigating the accumulation of distribution shifts. Specifically we propose a Distribution-aware Masking (DaM) mechanism to adaptively sample masked positions followed by establishing consistency constraints between the masked target samples and the original target samples. Additionally for masked tokens we utilize an efficient decoder to reconstruct a hand-crafted feature descriptor (e.g. Histograms of Oriented Gradients) leveraging its invariant properties to boost task-relevant representations. Through conducting extensive experiments on four widely recognized benchmarks our proposed method attains state-of-the-art performance in both classification and segmentation CTTA tasks.

Most continual segmentation methods tackle the problem as a per-pixel classification task. However such a paradigm is very challenging and we find query-based segmenters with built-in objectness have inherent advantages compared with per-pixel ones as objectness has strong transfer ability and forgetting resistance. Based on these findings we propose CoMasTRe by disentangling continual segmentation into two stages: forgetting-resistant continual objectness learning and well-researched continual classification. CoMasTRe uses a two-stage segmenter learning class-agnostic mask proposals at the first stage and leaving recognition to the second stage. During continual learning a simple but effective distillation is adopted to strengthen objectness. To further mitigate the forgetting of old classes we design a multi-label class distillation strategy suited for segmentation. We assess the effectiveness of CoMasTRe on PASCAL VOC and ADE20K. Extensive experiments show that our method outperforms per-pixel and query-based methods on both datasets. Code will be available at https://github.com/jordangong/CoMasTRe.

Embodied AI such as autonomous vehicles suffers from insufficient long-tailed data because it must be obtained from the physical world. In fact data must be continuously obtained in a series of small batches and the model must also be continuously trained to achieve generalizability and scalability by improving the biased data distribution. This paper addresses the training cost and catastrophic forgetting problems when continuously updating models to adapt to incoming small batches from various environments for real-world motion prediction in autonomous driving. To this end we propose a novel continual motion prediction (CMP) learning framework based on sparse meta-representation learning and an optimal memory buffer retention strategy. In meta-representation learning a model explicitly learns a sparse representation of each driving environment from road geometry to vehicle states by training to reduce catastrophic forgetting based on an augmented modulation network with sparsity regularization. Also in the adaptation phase We develop an Optimal Memory Buffer Retention strategy that smartly preserves diverse samples by focusing on representation similarity. This approach handles the nuanced task distribution shifts characteristic of motion prediction datasets ensuring our model stays responsive to evolving input variations without requiring extensive resources. The experiment results demonstrate that the proposed method shows superior adaptation performance to the conventional continual learning approach which is developed using a synthetic dataset for the continual learning problem.

For privacy and security concerns the need to erase unwanted information from pre-trained vision models is becoming evident nowadays. In real-world scenarios erasure requests originate at any time from both users and model owners. These requests usually form a sequence. Therefore under such a setting selective information is expected to be continuously removed from a pre-trained model while maintaining the rest. We define this problem as continual forgetting and identify two key challenges. (i) For unwanted knowledge efficient and effective deleting is crucial. (ii) For remaining knowledge the impact brought by the forgetting procedure should be minimal. To address them we propose Group Sparse LoRA (GS-LoRA). Specifically towards (i) we use LoRA modules to fine-tune the FFN layers in Transformer blocks for each forgetting task independently and towards (ii) a simple group sparse regularization is adopted enabling automatic selection of specific LoRA groups and zeroing out the others. GS-LoRA is effective parameter-efficient data-efficient and easy to implement. We conduct extensive experiments on face recognition object detection and image classification and demonstrate that GS-LoRA manages to forget specific classes with minimal impact on other classes. Codes will be released on https://github.com/bjzhb666/GS-LoRA.

Multimodal intent recognition (MIR) aims to perceive the human intent polarity via language visual and acoustic modalities. The inherent intent ambiguity makes it challenging to recognize in multimodal scenarios. Existing MIR methods tend to model the individual video independently ignoring global contextual information across videos. This learning manner inevitably introduces perception biases exacerbated by the inconsistencies of the multimodal representation amplifying the intent uncertainty. This challenge motivates us to explore effective global context modeling. Thus we propose a context-augmented global contrast (CAGC) method to capture rich global context features by mining both intra-and cross-video context interactions for MIR. Concretely we design a context-augmented transformer module to extract global context dependencies across videos. To further alleviate error accumulation and interference we develop a cross-video bank that retrieves effective video sources by considering both intentional tendency and video similarity. Furthermore we introduce a global context-guided contrastive learning scheme designed to mitigate inconsistencies arising from global context and individual modalities in different feature spaces. This scheme incorporates global cues as the supervision to capture robust the multimodal intent representation. Experiments demonstrate CAGC obtains superior performance than state-of-the-art MIR methods. We also generalize our approach to a closely related task multimodal sentiment analysis achieving the comparable performance.

Despite great improvements in semantic segmentation challenges persist because of the lack of local/global contexts and the relationship between them. In this paper we propose Contextrast a contrastive learning-based semantic segmentation method that allows to capture local/global contexts and comprehend their relationships. Our proposed method comprises two parts: a) contextual contrastive learning (CCL) and b) boundary-aware negative (BANE) sampling. Contextual contrastive learning obtains local/global context from multi-scale feature aggregation and inter/intra-relationship of features for better discrimination capabilities. Meanwhile BANE sampling selects embedding features along the boundaries of incorrectly predicted regions to employ them as harder negative samples on our contrastive learning resolving segmentation issues along the boundary region by exploiting fine-grained details. We demonstrate that our Contextrast substantially enhances the performance of semantic segmentation networks outperforming state-of-the-art contrastive learning approaches on diverse public datasets e.g. Cityscapes CamVid PASCAL-C COCO-Stuff and ADE20K without an increase in computational cost during inference.

Compositional Zero-Shot Learning (CZSL) aims to recognize unseen attribute-object pairs based on a limited set of observed examples. Current CZSL methodologies despite their advancements tend to neglect the distinct specificity levels present in attributes. For instance given images of sliced strawberries they may fail to prioritize `Sliced-Strawberry' over a generic `Red-Strawberry' despite the former being more informative. They also suffer from ballooning search space when shifting from Close-World (CW) to Open-World (OW) CZSL. To address the issues we introduce the Context-based and Diversity-driven Specificity learning framework for CZSL (CDS-CZSL). Our framework evaluates the specificity of attributes by considering the diversity of objects they apply to and their related context. This novel approach allows for more accurate predictions by emphasizing specific attribute-object pairs and improves composition filtering in OW-CZSL. We conduct experiments in both CW and OW scenarios and our model achieves state-of-the-art results across three datasets.

Spatio-temporal video grounding (or STVG) task aims at locating a spatio-temporal tube for a specific instance given a text query. Despite advancements current methods easily suffer the distractors or heavy object appearance variations in videos due to insufficient object information from the text leading to degradation. Addressing this we propose a novel framework context-guided STVG (CG-STVG) which mines discriminative instance context for object in videos and applies it as a supplementary guidance for target localization. The key of CG-STVG lies in two specially designed modules including instance context generation (ICG) which focuses on discovering visual context information (in both appearance and motion) of the instance and instance context refinement (ICR) which aims to improve the instance context from ICG by eliminating irrelevant or even harmful information from the context. During grounding ICG together with ICR are deployed at each decoding stage of a Transformer architecture for instance context learning. Particularly instance context learned from one decoding stage is fed to the next stage and leveraged as a guidance containing rich and discriminative object feature to enhance the target-awareness in decoding feature which conversely benefits generating better new instance context for improving localization finally. Compared to existing methods CG-STVG enjoys object information in text query and guidance from mined instance visual context for more accurate target localization. In our experiments on three benchmarks including HCSTVG-v1/-v2 and VidSTG CG-STVG sets new state-of-the-arts in m_tIoU and m_vIoU on all of them showing efficacy. Code is released at https://github.com/HengLan/CGSTVG.