arXiv subjects

Cristina Lazar

Publications and source records attributed to Cristina Lazar.

4 recordsLinked to original sources

arXiv2026

Learning to Understand Body Language from Flight through Robust 3D Avatar Placing

Perceiving human motion and intent at long range is a prerequisite for socially intelligent aerial robots, yet the data to learn it barely exists. We introduce Drones2BodyLanguage, a dataset grounding human motion in real UAV footage: avatars manifesting ten communicative intents are placed into unmodified 4K drone scenes with metrically correct position, scale and orientation, maintained over hundreds of frames of camera motion. Enabling it is a lightweight geometric world model of the local scene - semantically selected anchors lifted to 3D through streaming monocular depth - in which a placement point is predicted as an affine anchor combination with provably rigid-invariant weights, and re-rendered under an SVD-fitted ground rotation. Across twelve architectures on scene- and motion-disjoint splits, training on placed data lifts mean intent accuracy by a wide margin for real, retargeted and generated motion alike, with gains confirmed on two in-the-wild scenes.

cs.CV↗

arXiv2026

Real-time body pose non-verbal communication with a consistency-based reliability measure

Body movement communicates intent at distances and in conditions where neither the face, nor speech can be captured. We study the recognition of communicative intent from 2D body pose alone. We argue that body motion is a reliable signal especially in scenarios that require real time low-cost on-device person-to-robot communication in long distance environments, such as rescue missions. However, existing resources do not isolate this signal. Affective corpora combine body, face, voice and text, while skeleton action-recognition benchmarks label the action performed rather than the message conveyed. We release a dataset of real frames of full-body pose covering ten communicative intents and we compare it against other real (IPC) and synthetic (MotionLCM, VEO3.1, Kimodo) ones that span a range of difficulty. We target systems that can run on a robot's limited onboard hardware. We benchmark multiple models, from skeleton graph classifiers to joint motion-forecasting networks, and report performance metrics together with frame rate on an embedded GPU (NVIDIA Orin~Nano), since speed matters as much as accuracy in our scenario. Finally, we show that a model's own autoregressive self-consistency works as an unsupervised reliability signal. We give a short proof that bounds the probability that a self-consistent prediction is correct, show that this probability grows with the number of consistent steps, and identify the conditions under which a confident prediction can still be false, benchmarked against industry-standard metrics.

cs.CV↗

arXiv2026

Non-verbal Real-time Human-AI Interaction in Constrained Robotic Environments

We study the ongoing debate regarding the statistical fidelity of AI-generated data compared to human-generated data in the context of non-verbal communication using full body motion. Concretely, we ask if contemporary generative models move beyond surface mimicry to participate in the silent, but expressive dialogue of body language. We tackle this question by introducing the first framework that generates a natural non-verbal interaction between Human and AI in real-time from 2D body keypoints. Our experiments utilize four lightweight architectures which run at up to 100 FPS on an NVIDIA Orin Nano, effectively closing the perception-action loop needed for natural Human-AI interaction. We trained on 437 human video clips and demonstrated that pretraining on synthetically-generated sequences reduces motion errors significantly, without sacrificing speed. Yet, a measurable reality gap persists. When the best model is evaluated on keypoints extracted from cutting-edge text-to-video systems, such as SORA and VEO, we observe that performance drops on SORA-generated clips. However, it degrades far less on VEO, suggesting that temporal coherence, not image fidelity, drives real-world performance. Our results demonstrate that statistically distinguishable differences persist between Human and AI motion.

cs.CV↗

arXiv2024

Maia: A Real-time Non-Verbal Chat for Human-AI Interaction

Modeling face-to-face communication in computer vision, which focuses on recognizing and analyzing nonverbal cues and behaviors during interactions, serves as the foundation for our proposed alternative to text-based Human-AI interaction. By leveraging nonverbal visual communication, through facial expressions, head and body movements, we aim to enhance engagement and capture the user's attention through a novel improvisational element, that goes beyond mirroring gestures. Our goal is to track and analyze facial expressions, and other nonverbal cues in real-time, and use this information to build models that can predict and understand human behavior. Operating in real-time and requiring minimal computational resources, our approach signifies a major leap forward in making AI interactions more natural and accessible. We offer three different complementary approaches, based on retrieval, statistical, and deep learning techniques. A key novelty of our work is the integration of an artistic component atop an efficient human-computer interaction system, using art as a medium to transmit emotions. Our approach is not art-specific and can be adapted to various paintings, animations, and avatars. In our experiments, we compare state-of-the-art diffusion models as mediums for emotion translation in 2D, and our 3D avatar, Maia, that we introduce in this work, with not just facial movements but also body motions for a more natural and engaging experience. We demonstrate the effectiveness of our approach in translating AI-generated emotions into human-relatable expressions, through both human and automatic evaluation procedures, highlighting its potential to significantly enhance the naturalness and engagement of Human-AI interactions across various applications.

cs.CV↗