Hwasup Lim

Dr. Hwasup Lim

orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 October 2023 in Journal of Biomedical Informatics
Verified
Journal Article
Open access
AJAnkhzaya Jamsrandorj
Ankhzaya Jamsrandorj
DJDawoon Jung
Dawoon Jung
KKKonki Sravan Kumar
Konki Sravan Kumar
MAMuhammad Zeeshan Arshad
Muhammad Zeeshan Arshad
HLHwasup Lim
Hwasup Lim
KMKyung-Ryoul Mun
Kyung-Ryoul Mun
Accurate gait detection is crucial in utilizing the ample health information embedded in it. Vision-based approaches for gait detection have emerged as an alternative to the exacting sensor-based approaches, but their application has been rather limited due to complicated feature engineering processes and heavy reliance on lateral views. Thus, this study aimed to find a simple vision-based approach that is view-independent and accurate. A total of 22 participants performed six different actions representing standard and peculiar gaits, and the videos acquired from these actions were used as the input of the deep learning networks. Four networks, including a 2D convolutional neural network and an attention-based deep learning network, were trained with standard gaits, and their detection performance for both standard and peculiar gaits was assessed using measures including F1-scores. While all networks achieved remarkable detection performance, the CNN-Transformer network achieved the best performance for both standard and peculiar gaits. Little deviation by the speed of actions or view angles was found. The study is expected to contribute to the wider application of vision-based approaches in gait detection and gait-based health monitoring both at home and in clinical settings.

9 November 2018 in IEEE Transactions on Multimedia
Verified
Journal Article
Closed access
OCOuk Choi
Ouk Choi
YSYoung-Jun Son
Young-Jun Son
HLHwasup Lim
Hwasup Lim
SASang Chul Ahn
Sang Chul Ahn
We present a depth-based fingertip recognition method for interactive projectors. We use a depth camera attached to a projector, so it is possible to change the relative pose between the projector and the projection surface without manual recalibration. For detection and classification of fingertips, we propose to use cascaded random forests boosted by our 3D pose-normalized pixel-difference features. The ensemble probabilities from the cascaded random forests are used to define a score function of a subset of detected fingertips. By finding the subset maximizing the score function, the fingertips in the subset are correctly classified, and the remaining incorrectly detected fingertips are rejected. Experiments show that the proposed method outperforms conventional random forest and convolutional neural network classifiers. In addition, our developed applications show the advantage of the proposed method in assigning different roles to different fingers.

1 September 2011
Verified
Conference Paper
Closed access
YKYong Sun Kim
Yong Sun Kim
HLHwasup Lim
Hwasup Lim
OCOuk Choi
Ouk Choi
KLKeechang Lee
Keechang Lee
JKJames D. K. Kim
James D. K. Kim
CKChangyeong Kim
Changyeong Kim
Nonlocal means filtering is an edge-preserving denoising method whose filter weights are determined by Gaussian weighted patch similarities. The nonlocal means filter shows superior performance in removing additive Gaussian noise at the expense of high computational complexity. In this paper, we propose an efficient and effective denoising method by introducing a separable implementation of the nonlocal means filter and adopting a bilateral kernel for computing patch similarities. Experimental results demonstrate that the proposed method provides comparable performance to the original nonlocal means, with lower computational complexity.

28 September 2024 in Mathematics
Verified
Journal Article
Open access
PDF file
YCYoungdae Cho
Youngdae Cho
WSWooram Son
Wooram Son
JBJaewan Bak
Jaewan Bak
YLYisoo Lee
Yisoo Lee
HLHwasup Lim
Hwasup Lim
YCYoungwoon Cha
Youngwoon Cha
We envision a telepresence system that enhances remote work by facilitating both physical and immersive visual interactions between individuals. However, during robot teleoperation, communication often lacks realism, as users see the robot’s body rather than the remote individual. To address this, we propose a method for overlaying a digital human model onto a humanoid robot using XR visualization, enabling an immersive 3D telepresence experience. Our approach employs a learning-based method to estimate the 2D poses of the humanoid robot from head-worn stereo views, leveraging a newly collected dataset of full-body poses for humanoid robots. The stereo 2D poses and sparse inertial measurements from the remote operator are optimized to compute 3D poses over time. The digital human is localized from the perspective of a continuously moving observer, utilizing the estimated 3D pose of the humanoid robot. Our moving camera-based pose estimation method does not rely on any markers or external knowledge of the robot’s status, effectively overcoming challenges such as marker occlusion, calibration issues, and dependencies on headset tracking errors. We demonstrate the system in a remote physical training scenario, achieving real-time performance at 40 fps, which enables simultaneous immersive and physical interactions. Experimental results show that our learning-based 3D pose estimation method, which operates without prior knowledge of the robot, significantly outperforms alternative approaches requiring the robot’s global pose, particularly during rapid headset movements, achieving markerless digital human augmentation from head-worn views.

5 December 2019 in IEEE Access
Verified
Journal Article
Open access
JJJae Won Jang
Jae Won Jang
YKYoung Chan Kwon
Young Chan Kwon
HLHwasup Lim
Hwasup Lim
OCOuk Choi
Ouk Choi

16 April 2020 in Electronics
Verified
Journal Article
Open access
PDF file
YKYoung Chan Kwon
Young Chan Kwon
JJJae Won Jang
Jae Won Jang
HLHwasup Lim
Hwasup Lim
OCOuk Choi
Ouk Choi
Realistic personalized avatars can play an important role in social interactions in virtual reality, increasing body ownership, presence, and dominance. A simple way to obtain the texture of an avatar is to use a single front-view image of a human and to generate the hidden back-view image. The realism of the generated image is crucial in improving the overall texture quality, and subjective image quality assessment methods can play an important role in the evaluation. The subjective methods, however, require dozens of human assessors, a controlled environment, and time. This paper proposes a deep learning-based image reality assessment method, which is fully automatic and has a short testing time of nearly a quarter second per image. We train various discriminators to predict whether an image is real or generated. The trained discriminators are then used to give a mean opinion score for the reality of an image. Through experiments on human back-view images, we show that our learning-based mean opinion scores are close to their subjective counterparts in terms of the root mean square error between them.