EDBT 2026 Demo / reviewers in the wild / expert
Panos Achlioptas
dblp:203/8938
· DBLP profile ↗
16ranked-venue papers
6as first author
9since 2021 · last 2024
0000-0001-6427-6055ORCID · corroborated
Domains — the database's venue-derived domains; a paper can count in several
Graphics, computer vision, multimedia, augmented reality and games · 15 · 5 first-author · 9 since 2021Artificial intelligence and machine learning · 11 · 6 first-author · 6 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2024 | ScanEnts3D: Exploiting Phrase-to-3D-Object Correspondences for Improved Visio-Linguistic Models in 3D ScenesabstractThe two popular datasets ScanRefer [20] and ReferIt3D [5] connect natural language to real-world 3D scenes. In this paper, we curate a complementary dataset extending both the aforementioned ones. We associate all objects mentioned in a referential sentence with their underlying instances inside a 3D scene. In contrast, previous work did this only for a single object per sentence. Our Scan Entities in 3D (ScanEnts3D) dataset provides explicit correspondences between 369k objects across 84k referential sentences, covering 705 real-world scenes. We propose novel architecture modifications and losses that enable learning from this new type of data and improve the performance for both neural listening and language generation. For neural listening, we improve the SoTA in both the Nr3D and ScanRefer benchmarks by 4.3% and 5.0%, respectively. For language generation, we improve the SoTA by 13.2 CIDEr points on the Nr3D benchmark. For both of these tasks, the new type of data is only used to improve training, but no additional annotations are required at inference time. Our introduced dataset is available on the project’s webpage at https://scanents3d.github.io/. Ahmed Abdelreheem 0002, Kyle Olszewski, Hsin-Ying Lee 0001, Peter Wonka, Panos Achlioptas |
WACV | 5 |
| 2024 | Promptable Game Models: Text-guided Game Simulation via Masked Diffusion ModelsabstractNeural video game simulators emerged as powerful tools to generate and edit videos. Their idea is to represent games as the evolution of an environment’s state driven by the actions of its agents. While such a paradigm enables users toplaya game action-by-action, its rigidity precludes more semantic forms of control. To overcome this limitation, we augment game models withpromptsspecified as a set ofnatural languageactions anddesired states. The result—a Promptable Game Model (PGM)—makes it possible for a user toplaythe game by prompting it with high- and low-level action sequences. Most captivatingly, our PGM unlocks thedirector’s mode, where the game is played by specifying goals for the agents in the form of a prompt. This requires learning “game AI,” encapsulated by our animation model, to navigate the scene using high-level constraints, play against an adversary, and devise a strategy to win a point. To render the resulting state, we use a compositional NeRF representation encapsulated in our synthesis model. To foster future research, we present newly collected, annotated and calibrated Tennis and Minecraft datasets. Our method significantly outperforms existing neural video game simulators in terms of rendering quality and unlocks applications beyond the capabilities of the current state-of-the-art. Our framework, data, and models are available at snap-research.github.io/promptable-game-models. Willi Menapace, Aliaksandr Siarohin, Stéphane Lathuilière, Panos Achlioptas, Vladislav Golyanik, Sergey Tulyakov, Elisa Ricci 0001 |
ACM Trans. Graph. | 4 |
| 2023 | ShapeTalk: A Language Dataset and Framework for 3D Shape Edits and DeformationsabstractEditing 3D geometry is a challenging task requiring specialized skills. In this work, we aim to facilitate the task of editing the geometry of 3D models through the use of natural language. For example, we may want to modify a 3D chair model to “make its legs thinner” or to “open a hole in its back”. To tackle this problem in a manner that promotes open-ended language use and enables fine-grained shape edits, we introduce the most extensive existing corpus of natural language utterances describing shape differences: ShapeTalk. ShapeTalk contains over half a million discriminative utterances produced by contrasting the shapes of common 3D objects for a variety of object classes and degrees of similarity. We also introduce a generic framework, ChangeIt3D, which builds on ShapeTalk and can use an arbitrary 3D generative model of shapes to produce edits that align the output better with the edit or deformation description. Finally, we introduce metrics for the quantitative evaluation of language-assisted shape editing methods that reflect key desiderata within this editing setup. We note that ShapeTalk allows methods to be trained with explicit 3D-to-language data, bypassing the necessity of “lifting” 2D to 3D using methods like neural rendering, as required by extant 2D image-language foundation models. Our code and data are publicly available at https://changeit3d.github.io/. Panos Achlioptas, Ian Huang, Minhyuk Sung, Sergey Tulyakov, Leonidas J. Guibas |
CVPR | 1 |
| 2023 | Affection: Learning Affective Explanations for Real-World Visual DataabstractIn this work, we explore the space of emotional reactions induced by real-world images. For this, we first introduce a large-scale dataset that contains both categorical emotional reactions and free-form textual explanations for 85,007 publicly available images, analyzed by 6,283 annotators who were asked to indicate and explain how and why they felt when observing a particular image, with a total of 526,749 responses. Although emotional reactions are subjective and sensitive to context (personal mood, social status, past experiences) - we show that there is significant common ground to capture emotional responses with a large support in the subject population. In light of this observation, we ask the following questions: i) Can we develop neural networks that provide plausible affective responses to real-world visual data explained with language? ii) Can we steer such methods towards producing explanations with varying degrees of pragmatic language, justifying different emotional reactions by grounding them in the visual stimulus? Finally, iii) How to evaluate the performance of such methods for this novel task? In this work, we take the first steps in addressing all of these questions, paving the way for more human-centric and emotionally-aware image analysis systems. Our code and data are publicly available at https://affective-explanations.org. Panos Achlioptas, Maks Ovsjanikov, Leonidas J. Guibas, Sergey Tulyakov |
CVPR | 1 |
| 2022 | PartGlot: Learning Shape Part Segmentation from Language Reference GamesabstractWe introduce PartGlot, a neural framework and associated architectures for learning semantic part segmentation of 3D shape geometry, based solely on part referential language. We exploit the fact that linguistic descriptions of a shape can provide priors on the shape's parts - as natural language has evolved to reflect human perception of the compositional structure of objects, essential to their recognition and use. For training we use ShapeGlot's paired geometry /language data collected via a reference game where a speaker produces an utterance to differentiate a target shape from two distractors and the listener has to find the target based on this utterance [3]. Our network is designed to solve this target multi-modal recognition problem, by carefully incorporating a Transformer-based attention module so that the output attention can precisely highlight the semantic part or parts described in the language. Remarkably, the network operates without any direct supervision on the 3D geometry itself. Furthermore, we also demonstrate that the learned part information is generaliz-able to shape classes unseen during training. Our approach opens the possibility of learning 3D shape parts from language alone, without the need for large-scale part geometry annotations, thus facilitating annotation acquisition. The code is available at https://github.com/63days/PartGlot. Juil Koo, Ian Huang, Panos Achlioptas, Leonidas J. Guibas, Minhyuk Sung |
CVPR | 3 |
| 2022 | Quantized GAN for Complex Music Generation from Dance Videos
Kyle Olszewski, Yu Wu 0011, Panos Achlioptas, Menglei Chai, Yan Yan 0002, Sergey Tulyakov |
ECCV (37) | 4 |
| 2022 | NeROIC: neural rendering of objects from online image collectionsabstractWe present a novel method to acquire object representations from online image collections, capturing high-quality geometry and material properties of arbitrary objects from photographs with varying cameras, illumination, and backgrounds. This enables various object-centric rendering applications such as novel-view synthesis, relighting, and harmonized background composition from challenging in-the-wild input. Using a multi-stage approach extending neural radiance fields, we first infer the surface geometry and refine the coarsely estimated initial camera parameters, while leveraging coarse foreground object masks to improve the training efficiency and geometry quality. We also introduce a robust normal estimation technique which eliminates the effect of geometric noise while retaining crucial details. Lastly, we extract surface material properties and ambient illumination, represented in spherical harmonics with extensions that handle transient elements, e.g. sharp shadows. The union of these components results in a highly modular and efficient object acquisition framework. Extensive evaluations and comparisons demonstrate the advantages of our approach in capturing high-quality geometry and appearance properties useful for rendering applications. Zhengfei Kuang, Kyle Olszewski, Menglei Chai, Zeng Huang, Panos Achlioptas, Sergey Tulyakov |
ACM Trans. Graph. | 5 |
| 2021 | ArtEmis: Affective Language for Visual ArtabstractWe present a novel large-scale dataset and accompanying machine learning models aimed at providing a detailed understanding of the interplay between visual content, its emotional effect, and explanations for the latter in language. In contrast to most existing annotation datasets in computer vision, we focus on the affective experience triggered by visual artworks and ask the annotators to indicate the dominant emotion they feel for a given image and, crucially, to also provide a grounded verbal explanation for their emotion choice. As we demonstrate below, this leads to a rich set of signals for both the objective content and the affective impact of an image, creating associations with abstract concepts (e.g., "freedom" or "love"), or references that go beyond what is directly visible, including visual similes and metaphors, or subjective references to personal experiences. We focus on visual art (e.g., paintings, artistic photographs) as it is a prime example of imagery created to elicit emotional responses from its viewers. Our dataset, termed ArtEmis, contains 455K emotion attributions and explanations from humans, on 80K artworks from WikiArt. Building on this data, we train and demonstrate a series of captioning systems capable of expressing and explaining emotions from visual stimuli. Remarkably, the captions produced by these systems often succeed in reflecting the semantic and abstract content of the image, going well beyond systems trained on existing datasets. The collected dataset and developed methods are available at https://artemisdataset.org. Panos Achlioptas, Maks Ovsjanikov, Kilichbek Haydarov, Mohamed Elhoseiny 0001, Leonidas J. Guibas |
CVPR | 1 |
| 2021 | Exploring Long Tail Visual Relationship Recognition with Large VocabularyabstractSeveral approaches have been proposed in recent literature to alleviate the long-tail problem, mainly in object classification tasks. In this paper, we make the first largescale study concerning the task of Long-Tail Visual Relationship Recognition (LTVRR). LTVRR aims at improving the learning of structured visual relationships that come from the long-tail (e.g., "rabbit grazing on grass"). In this setup, the subject, relation, and object classes each follow a long-tail distribution. To begin our study and make a future benchmark for the community, we introduce two LTVRR-related benchmarks, dubbed VG8K-LT and GQA-LT, built upon the widely used Visual Genome and GQA datasets. We use these benchmarks to study the performance of several state-of-the-art long-tail models on the LTVRR setup. Lastly, we propose a visiolinguistic hubless (VilHub) loss and a Mixup augmentation technique adapted to LTVRR setup, dubbed as RelMix. Both VilHub and RelMix can be easily integrated on top of existing models and despite being simple, our results show that they can remarkably improve the performance, especially on tail classes. Benchmarks, code, and models have been made available at: https://github.com/Vision-CAIR/LTVRR. Sherif Abdelkarim, Aniket Agarwal, Panos Achlioptas, Jun Chen 0021, Jiaji Huang, Boyang Li 0001, Kenneth Church 0001, Mohamed Elhoseiny 0001 |
ICCV | 3 |
| 2020 | ReferIt3D: Neural Listeners for Fine-Grained 3D Object Identification in Real-World Scenes
Panos Achlioptas, Ahmed Abdelreheem 0002, Fei Xia 0002, Mohamed Elhoseiny 0001, Leonidas J. Guibas |
ECCV (1) | 1 |
| 2020 | DeformSyncNet: Deformation transfer via synchronized shape deformation spacesabstractShape deformation is an important component in any geometry processing toolbox. The goal is to enable intuitive deformations of single or multiple shapes or to transfer example deformations to new shapes while preserving the plausibility of the deformed shape(s). Existing approaches assume access to point-level or part-level correspondence or establish them in a preprocessing phase, thus limiting the scope and generality of such approaches. We propose DeformSyncNet, a new approach that allows consistent and synchronized shape deformations without requiring explicit correspondence information. Technically, we achieve this by encoding deformations into a class-specific idealized latent space while decoding them into an individual, model-specific linear deformation action space, operating directly in 3D. The underlying encoding and decoding are performed by specialized (jointly trained) neural networks. By design, the inductive bias of our networks results in a deformation space with several desirable properties, such as path invariance across different deformation pathways, which are then also approximately preserved in real space. We qualitatively and quantitatively evaluate our framework against multiple alternative approaches and demonstrate improved performance. Minhyuk Sung, Zhenyu Jiang 0002, Panos Achlioptas, Niloy J. Mitra, Leonidas J. Guibas |
ACM Trans. Graph. | 3 |
| 2019 | Shapeglot: Learning Language for Shape DifferentiationabstractIn this work we explore how fine-grained differences between the shapes of common objects are expressed in language, grounded on 2D and/or 3D object representations. We first build a large scale, carefully controlled dataset of human utterances each of which refers to a 2D rendering of a 3D CAD model so as to distinguish it from a set of shape-wise similar alternatives. Using this dataset, we develop neural language understanding (listening) and production (speaking) models that vary in their grounding (pure 3D forms via point-clouds vs. rendered 2D images), the degree of pragmatic reasoning captured (e.g. speakers that reason about a listener or not), and the neural architecture (e.g. with or without attention). We find models that perform well with both synthetic and human partners, and with held out utterances and objects. We also find that these models are capable of zero-shot transfer learning to novel object classes (e.g. transfer from training on chairs to testing on lamps), as well as to real-world images drawn from furniture catalogs. Lesion studies indicate that the neural listeners depend heavily on part-related words and associate these words correctly with visual parts of objects (without any explicit supervision on such parts), and that transfer to novel classes is most successful when known part-related words are available. This work illustrates a practical approach to language grounding, and provides a novel case study in the relationship between object shape and linguistic structure when it comes to object differentiation. Panos Achlioptas, Leonidas J. Guibas, Noah D. Goodman, Judy Fan, Robert D. Hawkins |
ICCV | 1 |
| 2019 | Composite Shape Modeling via Latent Space FactorizationabstractWe present a novel neural network architecture, termed Decomposer-Composer, for semantic structure-aware 3D shape modeling. Our method utilizes an auto-encoder-based pipeline, and produces a novel factorized shape embedding space, where the semantic structure of the shape collection translates into a data-dependent sub-space factorization, and where shape composition and decomposition become simple linear operations on the embedding coordinates. We further propose to model shape assembly using an explicit learned part deformation module, which utilizes a 3D spatial transformer network to perform an in-network volumetric grid deformation, and which allows us to train the whole system end-to-end. The resulting network allows us to perform part-level shape manipulation, unattainable by existing approaches. Our extensive ablation study, comparison to baseline methods and qualitative analysis demonstrate the improved performance of the proposed method. Anastasia Dubrovina, Fei Xia 0002, Panos Achlioptas, Mira Shalah, Raphaël Groscot, Leonidas J. Guibas |
ICCV | 3 |
| 2019 | OperatorNet: Recovering 3D Shapes From Difference OperatorsabstractThis paper proposes a learning-based framework for reconstructing 3D shapes from functional operators, compactly encoded as small-sized matrices. To this end we introduce a novel neural architecture, called OperatorNet, which takes as input a set of linear operators representing a shape and produces its 3D embedding. We demonstrate that this approach significantly outperforms previous purely geometric methods for the same problem. Furthermore, we introduce a novel functional operator, which encodes the extrinsic or pose-dependent shape information, and thus complements purely intrinsic pose-oblivious operators, such as the classical Laplacian. Coupled with this novel operator, our reconstruction network achieves very high reconstruction accuracy, even in the presence of incomplete information about a shape, given a soft or functional map expressed in a reduced basis. Finally, we demonstrate that the multiplicative functional algebra enjoyed by these operators can be used to synthesize entirely new unseen shapes, in the context of shape interpolation and shape analogy applications. Ruqi Huang, Marie-Julie Rakotosaona, Panos Achlioptas, Leonidas J. Guibas, Maks Ovsjanikov |
ICCV | 3 |
| 2019 | Limit Shapes - A Tool for Understanding Shape Differences and Variability in 3D Model CollectionsabstractAbstract We propose a novel construction for extracting a central or limit shape in a shape collection, connected via a functional map network. Our approach is based on enriching the latent space induced by a functional map network with an additional natural metric structure. We call this shape‐like dual object the limit shape and show that its construction avoids many of the biases introduced by selecting a fixed base shape or template. We also show that shape differences between real shapes and the limit shape can be computed and characterize the unique properties of each shape in a collection – leading to a compact and rich shape representation. We demonstrate the utility of this representation in a range of shape analysis tasks, including improving functional maps in difficult situations through the mediation of limit shapes, understanding and visualizing the variability within and across different shape classes, and several others. In this way, our analysis sheds light on the missing geometric structure in previously used latent functional spaces, demonstrates how these can be addressed and finally enables a compact and meaningful shape representation useful in a variety of practical applications. Ruqi Huang, Panos Achlioptas, Leonidas J. Guibas, Maks Ovsjanikov |
Comput. Graph. Forum | 2 |
| 2018 | Learning Representations and Generative Models for 3D Point CloudsabstractThree-dimensional geometric data offer an excellent domain for studying representation learning and generative modeling. In this paper, we look at geometric data represented as point clouds. We introduce a deep AutoEncoder (AE) network with state-of-the-art reconstruction quality and generalization ability. The learned representations outperform existing methods on 3D recognition tasks and enable shape editing via simple algebraic manipulations, such as semantic part editing, shape analogies and shape interpolation, as well as shape completion. We perform a thorough study of different generative models including GANs operating on the raw point clouds, significantly improved GANs trained in the fixed latent space of our AEs, and Gaussian Mixture Models (GMMs). To quantitatively evaluate generative models we introduce measures of sample fidelity and diversity based on matchings between sets of point clouds. Interestingly, our evaluation of generalization, fidelity and diversity reveals that GMMs trained in the latent space of our AEs yield the best results overall. Panos Achlioptas, Olga Diamanti, Ioannis Mitliagkas, Leonidas J. Guibas |
ICML | 1 |