Abdelrahman Elskhawy

Seok-Young Kim, Abdelrahman Elskhawy, Taewook Ha et al.

We present DeWorldSG, a novel framework that generates spatio-temporally robust 3D Semantic Scene Graphs from RGB-D sequences. Existing methods often struggle to construct reliable 3D scene graphs due to unstable 3D object representations and missing relations caused by frame-wise inference. DeWorldSG addresses these issues by estimating instance-level geometric 3D Gaussian distributions through depth-guided filtering and representing each object as a probabilistic 3D node rather than a single projected point. To mitigate relational sparsity from frame-wise inference, our framework further aggregates spatiotemporal evidence across object pairs and refines relations using contextual priors derived from a world model (V-JEPA 2). Experiments on the 3DSSG and ReplicaSSG datasets demonstrate state-of-the-art (SoTA) performance in both object and predicate prediction, while producing temporally consistent scene structures. In particular, our method improves triplet recall by 77.4% and predicate recall by 23.2% over prior SoTA approaches, making it suitable for robotic manipulation and AR applications. Our code and models are open-sourced.

Abdelrahman Elskhawy, Mengze Li, Nassir Navab et al.

In Scene Graph Generation (SGG), structured representations are extracted from visual inputs as object nodes and connecting predicates, enabling image-based reasoning for diverse downstream tasks. While fully supervised SGG has improved steadily, it suffers from training bias due to limited curated data and long-tail predicate distributions, leading to poor predicate diversity and degraded downstream performance. We present PRISM-0, a zero-shot open-vocabulary SGG framework that leverages foundation models in a bottom-up pipeline to capture a broad spectrum of predicates. Detected object pairs are filtered, described via a Vision-Language Model (VLM), and processed by a Large Language Model (LLM) to generate fine- and coarse-grained predicates, which are then validated by a Visual Question Answering (VQA) model. PRISM-0 modular, dataset-independent design enriches existing SGG datasets such as Visual Genome and produces diverse, unbiased graphs. While operating entirely in a zero-shot setting, PRISM-0 achieves performance on par with state-of-the-art weakly-supervised models on SGG benchmarks and even state-of-the-art supervised methods in tasks such as Sentence-to-Graph Retrieval.

Abdelrahman Elskhawy, Aneta Lisowska, Matthias Keicher et al.

Deep learning organ segmentation approaches require large amounts of annotated training data, which is limited in supply due to reasons of confidentiality and the time required for expert manual annotation. Therefore, being able to train models incrementally without having access to previously used data is desirable. A common form of sequential training is fine tuning (FT). In this setting, a model learns a new task effectively, but loses performance on previously learned tasks. The Learning without Forgetting (LwF) approach addresses this issue via replaying its own prediction for past tasks during model training. In this work, we evaluate FT and LwF for class incremental learning in multi-organ segmentation using the publicly available AAPM dataset. We show that LwF can successfully retain knowledge on previous segmentations, however, its ability to learn a new class decreases with the addition of each class. To address this problem we propose an adversarial continual learning segmentation approach (ACLSeg), which disentangles feature space into task-specific and task-invariant features. This enables preservation of performance on past tasks and effective acquisition of new knowledge.