Norimasa Kobori

dblp:198/3892 · DBLP profile ↗
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11ranked-venue papers
1as first author
10since 2021 · last 2025
—ORCID · none

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Graphics, computer vision, multimedia, augmented reality and games · 9 · 1 first-author · 8 since 2021Artificial intelligence and machine learning · 8 · 8 since 2021Human-computer interaction and ubiquitous computing · 2 · 1 first-author · 1 since 2021
YearPublicationVenuePosition
2025 GA3CE: Unconstrained 3D Gaze Estimation with Gaze-Aware 3D Context Encoding
abstract
We propose a novel 3D gaze estimation approach that learns spatial relationships between the subject and objects in the scene, and outputs 3D gaze direction. Our method targets unconstrained settings, including cases where close-up views of the subject’s eyes are unavailable, such as when the subject is distant or facing away. Previous approaches typically rely on either 2D appearance alone or incorporate limited spatial cues using depth maps in the non-learnable post-processing step. Estimating 3D gaze direction from 2D observations in these scenarios is challenging; variations in subject pose, scene layout, and gaze direction, combined with differing camera poses, yield diverse 2D appearances and 3D gaze directions even when targeting the same 3D scene. To address this issue, we propose GA3CE: Gaze-Aware 3D Context Encoding. Our method represents subject and scene using 3D poses and object positions, treating them as 3D context to learn spatial relationships in 3D space. Inspired by human vision, we align this context in an egocentric space, significantly reducing spatial complexity. Furthermore, we propose D3(direction-distance-decomposed) positional encoding to better capture the spatial relationship between 3D context and gaze direction in direction and distance space. Experiments demonstrate substantial improvements, reducing mean angle error by 13%–37% compared to leading baselines on benchmark datasets in single-frame settings.
Yuki Kawana, Shintaro Shiba, Quan Kong, Norimasa Kobori
CVPR4
2025 Synthetic Visual Genome
abstract
Reasoning over visual relationships—spatial, functional, interactional, social, etc.—is considered to be a fundamental component of human cognition. Yet, despite the major advances in visual comprehension in multimodal language models (MLMs), precise reasoning over relationships and their generations remains a challenge. We introduce Robin: an MLM instruction-tuned with densely annotated relationships capable of constructing high-quality dense scene graphs at scale. To train Robin, we curate SVG1, a synthetic scene graph dataset by completing the missing relations of selected objects in existing scene graphs using a teacher MLM and a carefully designed filtering process to ensure high-quality. To generate more accurate and rich scene graphs at scale for any image, we introduce SG-Edit: a self-distillation framework where GPT-4o further refines Robin’s predicted scene graphs by removing unlikely relations and/or suggesting relevant ones. In total, our dataset contains 146K images and 5.6M relationships for 2.6M objects. Results show that our Robin-3B model, despite being trained on less than 3 million instances, outperforms similar-size models trained on over 300 million instances on relationship understanding benchmarks, and even surpasses larger models up to 13B parameters. Notably, it achieves state-of-the-art performance in referring expression comprehension with a score of 88.2, surpassing the previous best of 87.4. Our results suggest that training on the refined scene graph data is crucial to maintaining high performance across diverse visual reasoning tasks2.
Zixian Ma, Chenhao Zheng, Cheng-Yu Hsieh, Ximing Lu, Khyathi Raghavi Chandu, Quan Kong, Norimasa Kobori, Ali Farhadi, Yejin Choi 0001, Ranjay Krishna
CVPR9
2025 One Trajectory, One Token: Grounded Video Tokenization Via Panoptic Sub-Object Trajectory
Chenhao Zheng, Jieyu Zhang 0001, Mohammadreza Salehi, Vishnu Iyengar, Norimasa Kobori, Quan Kong, Ranjay Krishna
ICCV6
2025 An Embodied AR Navigation Agent: Integrating BIM with Retrieval-Augmented Generation for Language Guidance
abstract
Delivering intelligent and adaptive navigation assistance in augmented reality (AR) requires more than visual cues, as it demands systems capable of interpreting flexible user intent and reasoning over both spatial and semantic context. Prior AR navigation systems often rely on rigid input schemes or predefined commands, which limit the utility of rich building data and hinder natural interaction. In this work, we propose an embodied AR navigation system that integrates Building Information Modeling (BIM) with a multi-agent retrieval-augmented generation (RAG) framework to support flexible, language-driven goal retrieval and route planning. The system orchestrates three language agents, Triage, Search, and Response, built on large language models (LLMs), which enables robust interpretation of open-ended queries and spatial reasoning using BIM data. Navigation guidance is delivered through an embodied AR agent, equipped with voice interaction and locomotion, to enhance user experience. A real-world user study yields a System Usability Scale (SUS) score of 80.5, indicating excellent usability, and comparative evaluations show that the embodied interface can significantly improves users' perception of system intelligence. These results underscore the importance and potential of language-grounded reasoning and embodiment in the design of user-centered AR navigation systems. Video demonstrations are available at https://woven-visionai.github.io/ar-navigation-agent-project.
Hsuan-Kung Yang, Tsu-Ching Hsiao, Ryoichiro Oka, Ryuya Nishino, Satoko Tofukuji, Norimasa Kobori
ISMAR6
2025 Distance Estimation in Outdoor Driving Environments Using Phase-Only Correlation Method with Event Cameras
abstract
With the global proliferation of autonomous driving technology, the advancement of sensor technology is essential to ensure its safety. In particular, sensor fusion plays a crucial role in autonomous driving systems. However, equipping vehicles with multiple sensors leads to increased costs, making it necessary to have a single sensor that can perform multiple roles. This study focuses on event cameras, exploring their potential among various sensor technologies. Event cameras possess characteristics such as high dynamic range, low latency, and high temporal resolution, and they can also leverage visible light communication. This enables high visibility in low-light and backlit environments, as well as excellent performance in detecting pedestrian movements and acquiring traffic information between traffic lights and vehicles. These characteristics are particularly beneficial for autonomous driving systems. Additionally, if distance estimation functionality can be provided by the event camera, it allows a single sensor to perform multiple roles, offering significant advantages in terms of cost efficiency. In this study, we achieved distance estimation based on triangulation using an event camera and two points on an LED bar installed along a road. Furthermore, by employing the phase-only correlation method, we achieved sub-pixel precision in estimating the distance between two points on the LED bar, enabling even more accurate distance estimation. This approach performed monocular distance estimation in outdoor driving environments at distances ranging from 20 to 60 meters, achieving a success rate of over 90 % with errors of less than 0.5 meters. We are considering implementing position estimation in the future, with the current distance estimation technology forming the foundation for this. By achieving high-precision distance estimation, the vehicle's position relative to surrounding ITS smart poles can be accurately determined, enabling more precise position estimation. This will allow autonomous vehicles to know their exact position in real-time and select the optimal driving route based on surrounding traffic conditions and road conditions. Ultimately, we believe that this technology can contribute to the development of a smart transportation system in the city.
Masataka Kobayashi, Shintaro Shiba, Quan Kong, Norimasa Kobori, Tsukasa Shimizu, Shan Lu 0003, Takaya Yamazato
IV4
2025 Evaluation of Mobile Environment for Vehicular Visible Light Communication Using Multiple LEDs and Event Cameras
abstract
In the fields of Advanced Driver Assistance Systems (ADAS) and Autonomous Driving (AD), sensors that serve as the “eyes” for sensing the vehicle's surrounding environment are essential. Traditionally, image sensors and LiDAR have played this role. However, a new type of vision sensor, event cameras, has recently attracted attention. Event cameras respond to changes in the surrounding environment (e.g., motion), exhibit strong robustness against motion blur, and perform well in high dynamic range environments, which are desirable in robotics applications. Furthermore, the asynchronous and low-latency principles of data acquisition make event cameras suitable for optical communication. By adding communication functionality to event cameras, it becomes possible to utilize I2V communication to immediately share information about forward collisions, sudden braking, and road conditions, thereby contributing to hazard avoidance. Additionally, receiving information such as signal timing and traffic volume enables speed adjustment and optimal route selection, facilitating more efficient driving. In this study, we construct a vehicle visible light communication system where event cameras are receivers, and multiple LEDs are transmitters. In driving scenes, the system tracks the transmitter positions and separates densely packed LED light sources using pilot sequences based on Walsh-Hadamard codes. As a result, outdoor vehicle experiments demonstrate error-free communication under conditions where the transmitter-receiver distance was within 40 meters and the vehicle's driving speed was 30 km/h (8.3 m/s).
Ryota Soga, Shintaro Shiba, Quan Kong, Norimasa Kobori, Tsukasa Shimizu, Shan Lu 0003, Takaya Yamazato
IV4
2024 WTS: A Pedestrian-Centric Traffic Video Dataset for Fine-Grained Spatial-Temporal Understanding
Quan Kong, Yuki Kawana, Rajat Saini, Jingjing Pan, Ta Gu, Yohei Ozao, Istvan Balazs Opra, Yoichi Sato 0001, Norimasa Kobori
ECCV (76)10
2024 Reprojection Errors as Prompts for Efficient Scene Coordinate Regression
Ting-Ru Liu, Hsuan-Kung Yang, Jou-Min Liu, Chun-Wei Huang, Tsung-Chih Chiang, Quan Kong, Norimasa Kobori, Chun-Yi Lee
ECCV (30)7
2023 DeCo: Decomposition and Reconstruction for Compositional Temporal Grounding via Coarse-to-Fine Contrastive Ranking
abstract
Understanding dense action in videos is a fundamental challenge towards the generalization of vision models. Several works show that compositionality is key to achieving generalization by combining known primitive elements, especially for handling novel composited structures. Compositional temporal grounding is the task of localizing dense action by using known words combined in novel ways in the form of novel query sentences for the actual grounding. In recent works, composition is assumed to be learned from pairs of whole videos and language embeddings through large scale self-supervised pre-training. Alternatively, one can process the video and language into word-level primitive elements, and then only learn fine-grained semantic correspondences. Both approaches do not consider the granularity of the compositions, where different query granularity corresponds to different video segments. Therefore, a good compositional representation should be sensitive to different video and query granularity. We propose a method to learn a coarse-to-fine compositional representation by decomposing the original query sentence into different granular levels, and then learning the correct correspondences between the video and recombined queries through a contrastive ranking constraint. Additionally, we run temporal boundary prediction in a coarse-to-fine manner for precise grounding boundary detection. Experiments are performed on two datasets, Charades-CG and ActivityNet-CG, showing the superior compositional generalizability of our approach.
Lijin Yang, Quan Kong, Hsuan-Kung Yang, Wadim Kehl, Yoichi Sato 0001, Norimasa Kobori
CVPR6
2021 DB-GAN: Boosting Object Recognition Under Strong Lighting Conditions
abstract
Driven by deep learning, object recognition has recently made a tremendous leap forward. Nonetheless, its accuracy often still suffers from several sources of variation that can be found in real-world images. Some of the most challenging variations are induced by changing lighting conditions. This paper presents a novel approach for tackling brightness variation in the domain of 2D object detection and 6D object pose estimation. Existing works aiming at improving robustness towards different lighting conditions are often grounded on classical computer vision contrast normalisation techniques or the acquisition of large amounts of annotated data in order to achieve invariance during training. While the former cannot generalise well to a wide range of illumination conditions, the latter is neither practical nor scalable. Hence, We propose the usage of Generative Adversarial Networks in order to learn how to normalise the illumination of an input image. Thereby, the generator is explicitly designed to normalise illumination in images so to enhance the object recognition performance. Extensive evaluations demonstrate that leveraging the generated data can significantly enhance the detection performance, outperforming all other state-of-the-art methods. We further constitute a natural extension focusing on white balance variations and introduce a new dataset for evaluation.
Luca Minciullo, Fabian Manhardt, Kei Yoshikawa, Sven Meier, Federico Tombari, Norimasa Kobori
WACV6
2017 Proposal of a spectral random dots marker using local feature for posture estimation
abstract
We propose a novel marker for robot's grasping task which has the following three aspects: (i) it is easy-to-find in a cluttered background, (ii) it is calculable for its posture (iii) its size is compact. The proposed marker is composed of a random dots pattern, and uses keypoint detection and a scale estimation by Spectral SIFT for dots detection and data decoding. The data is encoded by the scale size of dots, and the same dots in the marker work for both marker detection and data decoding. As a result, the proposed marker size can be compact. We confirmed the effectiveness of the proposed marker through experiments.
Norimasa Kobori, Daisuke Deguchi, Ichiro Ide, Hiroshi Murase
VR1