Sang-Il Choi

dblp:82/846 · DBLP profile ↗
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21ranked-venue papers
9as first author
7since 2021 · last 2026
—ORCID · conflict

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 10 · 5 first-author · 3 since 2021Graphics, computer vision, multimedia, augmented reality and games · 9 · 4 first-author · 4 since 2021Applied, interdisciplinary, general and emerging computing · 4 · 1 first-author · 3 since 2021Databases, data management, data science and information retrieval · 1Human-computer interaction and ubiquitous computing · 1

Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.

Artificial intelligence
2 papers
Generative modeling · 66% 3D vision · 26% Representation and self-supervised learning · 4%
Computer graphics and multimedia
1 paper
Visual content generation and editing · 100%

Topics — the 10 heaviest of 10, each with the papers that count most for it

TopicWeightPapersLastEvidence papers
Computer vision › 3D vision › neural rendering
3d gaussian splatting
0.912025
Roll Your Eyes: Gaze Redirection via Explicit 3D Eyeball Rotation · ACM Multimedia 2025
Computer vision › 3D vision › 3d scene modeling › scene representation
3d scene representation
0.912025
Roll Your Eyes: Gaze Redirection via Explicit 3D Eyeball Rotation · ACM Multimedia 2025
Machine learning › Generative modeling
diffusion model
0.912025
PersonaBooth: Personalized Text-to-Motion Generation · CVPR 2025
Machine learning › Generative modeling › motion generation
motion customization
0.912025
PersonaBooth: Personalized Text-to-Motion Generation · CVPR 2025
Machine learning › Generative modeling › diffusion model
motion diffusion
0.912025
PersonaBooth: Personalized Text-to-Motion Generation · CVPR 2025
Machine learning › Generative modeling
motion generation
0.912025
PersonaBooth: Personalized Text-to-Motion Generation · CVPR 2025
Machine learning › Generative modeling › diffusion model › human motion generation
text-to-motion generation
0.912025
PersonaBooth: Personalized Text-to-Motion Generation · CVPR 2025
Visual content generation and editing › face editing
gaze redirection
0.912025
Roll Your Eyes: Gaze Redirection via Explicit 3D Eyeball Rotation · ACM Multimedia 2025
Machine learning › Representation and self-supervised learning
contrastive learning
0.312025
PersonaBooth: Personalized Text-to-Motion Generation · CVPR 2025
Computer vision › Face, body and person analysis
gaze estimation
0.312025
Roll Your Eyes: Gaze Redirection via Explicit 3D Eyeball Rotation · ACM Multimedia 2025

Methods — techniques the papers use, named apart from their topics

neural radiance field · 1.73d gaussian splatting · 1.7multimodal fine-tuning · 0.9diffusion model · 0.9contrastive learning · 0.9
YearPublicationVenuePosition
2026 Quantification of thyroid nodules in multiple ultrasonography systems
Youngmin Kim 0004, Myeong-Gee Kim, SeokHwan Oh, Guil Jung, Hyeon-Jik Lee, Sang-Yun Kim 0003, Jungjae Son, Hyuksool Kwon, Sang-Il Choi, Hyeon-Min Bae
Medical Image Anal.9
2025 PersonaBooth: Personalized Text-to-Motion Generation
abstract
This paper introduces Motion Personalization, a new task that generates personalized motions aligned with text descriptions using several basic motions containing Persona. To support this novel task, we introduce a new large-scale motion dataset called PerMo (PersonaMotion), which captures the unique personas of multiple actors. We also propose a multi-modal finetuning method of a pretrained motion diffusion model called PersonaBooth. PersonaBooth addresses two main challenges: i) A significant distribution gap between the persona-focused PerMo dataset and the pretraining datasets, which lack persona-specific data, and ii) the difficulty of capturing a consistent persona from the motions vary in content (action type). To tackle the dataset distribution gap, we introduce a persona token to accept new persona features and perform multi-modal adaptation for both text and visuals during finetuning. To capture a consistent persona, we incorporate a contrastive learning technique to enhance intra-cohesion among samples with the same persona. Furthermore, we introduce a context-aware fusion mechanism to maximize the integration of persona cues from multiple input motions. PersonaBooth outperforms state-of-the-art motion style transfer methods, establishing a new benchmark for motion personalization.
Boeun Kim, Hea In Jeong, JungHoon Sung, Yihua Cheng, Jeongmin Lee 0007, Ju Yong Chang, Sang-Il Choi, Younggeun Choi 0001, Saim Shin, Hyung Jin Chang
CVPR7
2025 Roll Your Eyes: Gaze Redirection via Explicit 3D Eyeball Rotation
abstract
We propose a novel 3D gaze redirection framework that leverages an explicit 3D eyeball structure. Existing gaze redirection methods are typically based on neural radiance fields, which employ implicit neural representations via volume rendering. Unlike these NeRF-based approaches, where the rotation and translation of 3D representations are not explicitly modeled, we introduce a dedicated 3D eyeball structure to represent the eyeballs with 3D Gaussian Splatting (3DGS). Our method generates photorealistic images that faithfully reproduce the desired gaze direction by explicitly rotating and translating the 3D eyeball structure. In addition, we propose an adaptive deformation module that enables the replication of subtle muscle movements around the eyes. Through experiments conducted on the ETH-XGaze dataset, we demonstrate that our framework is capable of generating diverse novel gaze images, achieving superior image quality and gaze estimation accuracy compared to previous state-of-the-art methods.
YoungChan Choi, HengFei Wang, YiHua Cheng, Boeun Kim, Hyung Jin Chang, Younggeun Choi 0001, Sang-Il Choi
ACM Multimedia7
2024 Quantitative Assessment of Thyroid Nodules Through Ultrasound Imaging Analysis
Youngmin Kim 0004, Myeong-Gee Kim, SeokHwan Oh, Guil Jung, Hyeon-Jik Lee, Sang-Yun Kim 0003, Hyuksool Kwon, Sang-Il Choi, Hyeon-Min Bae
MICCAI (4)8
2024 Enhancing 3D hand pose estimation using SHaF: synthetic hand dataset including a forearm
Jaeyun Kim, Seon Ho Kim, Sang-Il Choi
Appl. Intell.4
2024 Uncertainty-aware ensemble model for stride length estimation in gait analysis
Jucheol Moon, Minwoo Tae, Sung-Han Rhim, Sang-Il Choi
Expert Syst. Appl.4
2023 Text-Guided Cross-Position Attention for Segmentation: Case of Medical Image
Go-Eun Lee, Seon Ho Kim, Jungchan Cho, Sang Tae Choi, Sang-Il Choi
MICCAI (5)5
2019 Detection of interacting groups based on geometric and social relations between individuals in an image
Haan-Ju Yoo, TaeKyu Eom, Jeong-Min Seo, Sang-Il Choi
Pattern Recognit.4
2018 Gait Type Classification Using Smart Insole Sensors
abstract
In this paper, we propose a gait type classification method using various sensors in a smart insole. The measured data are normalized to the unit step of the same length in order to reduce the variation of the speed according to the measurement point and the situation even within the same gait type. From the normalized data of the individual sensors, the discriminant features useful for gait type classification are extracted by using the Null-Space Linear Discriminant Analysis (NLDA), one of the representative discriminant analysis methods. As a result of experiments on the data measured for the seven gait types, our method gives a good performance of gait type classification.
Sang-Il Choi, Sungsin Lee, Hee-Chan Park, Hyunil Kim
TENCON1
2015 Continuous media fingerprinting against time-varying collusion attacks
Byung-Ho Cha, Sang-Il Choi
Inf. Sci.2
2015 Confidence Measure Using Composite Features for Eye Detection in a Face Recognition System
abstract
We propose a new confidence measure to evaluate the eye detection results and combine two different eye detectors. The confidence for the results of eye detection is measured by the distances from the test sample and the positive samples, where the distance is calculated in the composite feature space. By using the proposed confidence measure, we construct a hybrid detector by combining two different detectors, which are complementary to each other. The experimental results show that the proposed detector provides more accurate eye detection results and consequently results in better face recognition rates compared to when using an individual eye detector.
Sang-Il Choi, Yonggeol Lee, Chunghoon Kim
IEEE Signal Process. Lett.1
2013 Selective generation of Gabor features for fast face recognition on mobile devices
Jiyong Oh, Sang-Il Choi, Chunghoon Kim, Jungchan Cho, Chong-Ho Choi
Pattern Recognit. Lett.2
2012 Real-time 3-D face tracking and modeling from awebcam
abstract
We first infer a 3-D face model from a single frontal image using automatically extracted 2-D landmarks and deforming a generic 3-D model. Then, for any input image, we extract feature points and track them in 2-D. Given these correspondences, sometimes noisy and incorrect, we robustly estimate the 3-D head pose using PnP and a RANSAC process. As the head moves, we dynamically add new feature points to handle a large range of poses. When the tracker gets lost, due to motion blur or occlusions, the system re-initializes by matching feature points to the reference frontal image feature points. Our system runs in real-time (>;15Hz) on a standard CPU with a GPU card. We present results on stored video and will present a live demo, showing excellent tracking under large motion, fast movement, occlusion and facial expression variations. We also show comparative results with the ground truth BU head tracking dataset.
Jongmoo Choi, Yann Dumortier, Sang-Il Choi, Muhammad Bilal Ahmad, Gérard G. Medioni
WACV3
2012 Pixel selection based on discriminant features with application to face recognition
Sang-Il Choi, Chong-Ho Choi, Gu-Min Jeong, Nojun Kwak
Pattern Recognit. Lett.1
2012 Input variable selection for feature extraction in classification problems
Sang-Il Choi, Jiyong Oh, Chong-Ho Choi, Chunghoon Kim
Signal Process.1
2012 A New Biased Discriminant Analysis Using Composite Vectors for Eye Detection
abstract
We propose a new biased discriminant analysis (BDA) using composite vectors for eye detection. A composite vector consists of several pixels inside a window on an image. The covariance of composite vectors is obtained from their inner product and can be considered as a generalization of the covariance of pixels. The proposed composite BDA (C-BDA) method is a BDA using the covariance of composite vectors. We construct a hybrid cascade detector for eye detection, using Haar-like features in the earlier stages and composite features obtained from C-BDA in the later stages. The proposed detector runs in real time; its execution time is 5.5 ms on a typical PC. The experimental results for the CMU PIE database and our own real-world data set show that the proposed detector provides robust performance to several kinds of variations such as facial pose, illumination, eyeglasses, and partial occlusion. On the whole, the detection rate per pair of eyes is 98.0% for the 3604 face images of the CMU PIE database and 95.1% for the 2331 face images of the real-world data set. In particular, it provides a 99.7% detection rate for the 2120 CMU PIE images without glasses. Face recognition performance is also investigated using the eye coordinates from the proposed detector. The recognition results for the real-world data set show that the proposed detector gives similar performance to the method using manually located eye coordinates, showing that the accuracy of the proposed eye detector is comparable with that of the ground-truth data.
Chunghoon Kim, Sang-Il Choi, Matthew Turk 0001, Chong-Ho Choi
IEEE Trans. Syst. Man Cybern. Part B2
2011 Face recognition based on 2D images under illumination and pose variations
Sang-Il Choi, Chong-Ho Choi, Nojun Kwak
Pattern Recognit. Lett.1
2011 Shadow Compensation Using Fourier Analysis With Application to Face Recognition
abstract
Shadows that occur on face images due to illumination variation can change the appearance of a face and degrade face recognition performance. In this paper, we propose a new shadow compensation method based on the Fourier analysis for handling illumination variation. The face image deteriorated by shadow is restored by using the auxiliary magnitude, which compensates for the magnitude of the Fourier transform distorted due to the illumination variation. The experimental results for the CMU-PIE and Yale B databases show that the proposed method results in improved recognition performance under illumination variation.
Sang-Il Choi, Gu-Min Jeong
IEEE Signal Process. Lett.1
2008 Pixel selection in a face image based on discriminant features for face recognition
abstract
We propose a pixel selection method in a face image based on discriminant features for face recognition. By analyzing the relationship between the pixels in a face image and features extracted from face images, pixels that contain a large amount of discriminative information are selected, while pixels with less discriminative information are discarded. The proposed method orders the pixels based on the discriminative information in face recognition, instead of selecting salient a priori regions. Comparative experiments are performed using the FERET, CMU-PIE and Yale B databases. The experimental results show that the pixel selection results in improved recognition performance, especially under illumination variation.
Sang-Il Choi, Chong-Ho Choi, Gu-Min Jeong
FG1
2007 An Effective Face Recognition under Illumination and Pose Variations
abstract
Illumination and pose variations that occur on face images degrade the performance of face recognition. In this paper, we propose a novel approach for handling illumination and pose variations for face recognition simultaneously. We use the two-dimensional view-based face recognition method and the shadow compensation method to deal with both variations. We construct a subspace for each pose and use the relationship between facial feature points to identify the poses. Since most human faces are similar in shape, we can find the shadow characteristics that the illumination variation makes on a face depending on the direction of light. By using these characteristics, we can compensate for illumination variation in face images. The proposed method is simple and requires much less computational effort than the other methods based on 3D models, and at the same time, provides a comparable recognition rate.
Sang-Il Choi, Chong-Ho Choi
IJCNN1
2007 Shadow compensation in 2D images for face recognition
Sang-Il Choi, Chunghoon Kim, Chong-Ho Choi
Pattern Recognit.1