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Hajime Nagahara

20 accepted papers

2026

Coded-E2LF: Coded Aperture Light Field Imaging from Events

CVPR 2026

We propose Coded-E2LF (coded event to light field), a computational imaging method for acquiring a 4-D light field using a coded aperture and a stationary event-only camera. In a previous work, an imaging system similar to ours was adopted, but both events and intensity images were captured and used

Cited by 0SourceScholar
2026

From Pixels to Semantics: Unified Facial Action Representation Learning for Micro-Expression Analysis

ICLR 2026poster

Micro-expression recognition (MER) is highly challenging due to the subtle and rapid facial muscle movements and the scarcity of annotated data. Existing methods typically rely on pixel-level motion descriptors such as optical flow and frame difference, which tend to be sensitive to identity and lac…

Cited by 0SourceScholar
2025

Gaussian-Based Instance-Adaptive Intensity Modeling for Point-Supervised Facial Expression Spotting

ICLR 2025poster

Point-supervised facial expression spotting (P-FES) aims to localize facial expression instances in untrimmed videos, requiring only a single timestamp label for each instance during training. To address label sparsity, hard pseudo-labeling is often employed to propagate point labels to unlabeled fr…

2025

NeISF++: Neural Incident Stokes Field for Polarized Inverse Rendering of Conductors and Dielectrics

CVPR 2025poster

Recent inverse rendering methods have improved shape, material, and illumination reconstruction using polarization cues. However, they only support dielectrics, ignoring conductors, which are common in everyday life. Since conductors and dielectrics have different reflection properties, using previo…

Cited by 0SourcePDFScholar
2024

Deep Polarization Cues for Single-shot Shape and Subsurface Scattering Estimation

ECCV 2024poster

"In this work, we propose a novel learning-based method to jointly estimate the shape and subsurface scattering (SSS) parameters of translucent objects by utilizing polarization cues. Although polarization cues have been used in various applications, such as shape from polarization (SfP), BRDF estim…

Cited by 1SourcePDFScholar
2024

DiReCT: Diagnostic Reasoning for Clinical Notes via Large Language Models

NeurIPS 2024poster

Large language models (LLMs) have recently showcased remarkable capabilities, spanning a wide range of tasks and applications, including those in the medical domain. Models like GPT-4 excel in medical question answering but may face challenges in the lack of interpretability when handling complex ta…

2024

NeISF: Neural Incident Stokes Field for Geometry and Material Estimation

CVPR 2024highlight

Multi-view inverse rendering is the problem of estimating the scene parameters such as shapes materials or illuminations from a sequence of images captured under different viewpoints. Many approaches however assume single light bounce and thus fail to recover challenging scenarios like inter-reflect…

Cited by 8SourcePDFScholar
2024

Time-Efficient Light-Field Acquisition Using Coded Aperture and Events

CVPR 2024poster

We propose a computational imaging method for time-efficient light-field acquisition that combines a coded aperture with an event-based camera. Different from the conventional coded-aperture imaging method our method applies a sequence of coding patterns during a single exposure for an image frame.…

Cited by 3SourcePDFScholar
2023

Inverse Rendering of Translucent Objects Using Physical and Neural Renderers

CVPR 2023poster

In this work, we propose an inverse rendering model that estimates 3D shape, spatially-varying reflectance, homogeneous subsurface scattering parameters, and an environment illumination jointly from only a pair of captured images of a translucent object. In order to solve the ambiguity problem of in…

2023

Learning Bottleneck Concepts in Image Classification

CVPR 2023poster

Interpreting and explaining the behavior of deep neural networks is critical for many tasks. Explainable AI provides a way to address this challenge, mostly by providing per-pixel relevance to the decision. Yet, interpreting such explanations may require expert knowledge. Some recent attempts toward…

2022

Acquiring a Dynamic Light Field Through a Single-Shot Coded Image

CVPR 2022poster

We propose a method for compressively acquiring a dynamic light field (a 5-D volume) through a single-shot coded image (a 2-D measurement). We designed an imaging model that synchronously applies aperture coding and pixel-wise exposure coding within a single exposure time. This coding scheme enables…

Cited by 13PDFScholar
2022

Privacy-Preserving Action Recognition via Motion Difference Quantization

ECCV 2022poster

"The widespread use of smart computer vision systems in our personal spaces has led to an increased consciousness about the privacy and security risks that these systems pose. On the one hand, we want these systems to assist in our daily lives by understanding their surroundings, but on the other ha…

2021

SCOUTER: Slot Attention-Based Classifier for Explainable Image Recognition

ICCV 2021poster

Explainable artificial intelligence has been gaining attention in the past few years. However, most existing methods are based on gradients or intermediate features, which are not directly involved in the decision-making process of the classifier. In this paper, we propose a slot attention-based cla…

Cited by 58PDFcodeScholar
2021

WRIME: A New Dataset for Emotional Intensity Estimation with Subjective and Objective Annotations

NAACL 2021long

We annotate 17,000 SNS posts with both the writer’s subjective emotional intensity and the reader’s objective one to construct a Japanese emotion analysis dataset. In this study, we explore the difference between the emotional intensity of the writer and that of the readers with this dataset. We fou…

2020

Acquiring Dynamic Light Fields through Coded Aperture Camera

ECCV 2020poster

We investigate the problem of compressive acquisition of a dynamic light field. A promising solution for compressive light field acquisition is to use a coded aperture camera, with which an entire light field can be computationally reconstructed from several images captured through differently-coded…

Cited by 18SourcePDFScholar
2018

Joint optimization for compressive video sensing and reconstruction under hardware constraints

ECCV 2018poster

Compressive video sensing is the process of encoding multiple sub-frames into a single frame with controlled sensor exposures and reconstructing the sub-frames from the single compressed frame. It is known that spatially and temporally random exposures provide the most balanced compression in terms…

Cited by 41SourcePDFScholar
2018

Learning to Capture Light Fields through a Coded Aperture Camera

ECCV 2018poster

We propose a learning-based framework for acquiring a light field through a coded aperture camera. Acquiring a light field is a challenging task due to the amount of data. To make the acquisition process efficient, coded aperture cameras were successfully adopted; using these cameras, a light field…

Cited by 71SourcePDFScholar
2015

TransCut: Transparent Object Segmentation From a Light-Field Image

ICCV 2015poster

The segmentation of transparent objects can be very useful in computer vision applications. However, because they borrow texture from their background and have a similar appearance to their surroundings, transparent objects are not handled well by regular image segmentation methods. We propose a met…

Cited by 139PDFScholar