Hyunmi Lee

Ms. Hyunmi Lee

Transportation, Ajou University, Suwon, Gyeonggi, Republic of Korea
orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

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

Representative Publications

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22 September 2023 in Sensors
Verified
Journal Article
Open access
PDF file
Sungho SonSungho Son
Sungho Son
WLWoongsu Lee
Woongsu Lee
HJHyungi Jung
Hyungi Jung
JLJungki Lee
Jungki Lee
CKCharyung Kim
Charyung Kim
HRHan-Cheol Ryu
Han-Cheol Ryu
This study is the first to develop technology to evaluate the object recognition performance of camera sensors, which are increasingly important in autonomous vehicles owing to their relatively low price, and to verify the efficiency of camera recognition algorithms in obstruction situations. To this end, the concentration and color of the blockage and the type and color of the object were set as major factors, with their effects on camera recognition performance analyzed using a camera simulator based on a virtual test drive toolkit. The results show that the blockage concentration has the largest impact on object recognition, followed in order by the object type, blockage color, and object color. As for the blockage color, black exhibited better recognition performance than gray and yellow. In addition, changes in the blockage color affected the recognition of object types, resulting in different responses to each object. Through this study, we propose a blockage-based camera recognition performance evaluation method using simulation, and we establish an algorithm evaluation environment for various manufacturers through an interface with an actual camera. By suggesting the necessity and timing of future camera lens cleaning, we provide manufacturers with technical measures to improve the cleaning timing and camera safety.

16 September 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Sungho SonSungho Son
Sungho Son
WLWoongsu Lee
Woongsu Lee
JLJangmin Lee
Jangmin Lee
JLJungki Lee
Jungki Lee
HLHyunmi Lee
Hyunmi Lee
HRHan-Cheol Ryu
Han-Cheol Ryu
Pollutants degrade the performance of LiDAR sensors used in autonomous vehicles. Therefore, there is an urgent need to develop cleaning technology for these sensors. In this study, a solid-state LiDAR sensor was selected as a target and sprayed/dried with 2.5 g of a mixture of Arizona dust and Kaolin. To achieve optimal LiDAR cleaning performance, the washer pressure, spray time, spray angle, and target point were selected as major variables. Additionally, an optimal cleaning solution for each spray was formed via the design of experiments and optimization techniques. Model suitability was observed for the second spray through to the fourth. The cleaning rate increased with the washer pressure and spray time. The influence of these variables decreased as the number of sprays increased. The spray angle and target point exhibited no significant influence, but excellent cleaning was observed in some central areas. Verification test results were within 3% for the second through fourth sprays, indicating reliability. This study used a designed experiment with 30 scenarios to reveal optimized conditions for protecting the sensor performance from external visibility obstructions. Disclosing the optimization method lowers the barrier for sensor cleaning manufacturers to develop their own technology, which ultimately enhances safer and more efficient autonomous driving.

5 August 2025 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Sungho SonSungho Son
Sungho Son
HLHyunmi Lee
Hyunmi Lee
JYJIWOONG YANG
JIWOONG YANG
JLJungki Lee
Jungki Lee
Jeong ah JangJeong ah Jang
Jeong ah Jang
WLWoongsu Lee
Woongsu Lee
Light detection and ranging (LiDAR) provides three-dimensional environmental information that is critical for maintaining the safety and reliability of autonomous driving systems. However, dust accumulation on the LiDAR window can cause detection errors and degrade performance. This study determined the optimal spray conditions for accumulating dust to evaluate LiDAR sensor cleaning performance. A primary optimization experiment using spray pressure, spray speed, spray distance, and the number of sprays as variables showed that spray pressure and number of sprays had the most significant influence on the kinetic energy and distribution of dust particles. Notably, the interaction between spray distance and number of sprays—related to curvature effects—was identified as a key variable increasing process sensitivity. A supplementary experiment, which added spray angle as a variable, indicated that while spray pressure remained the most significant factor, spray angle and number of sprays had an indirect influence through interaction terms. Both experiments used the same response variable (point cloud data) interactions to stepwise analyze particle transfer and spatial diffusion. The resulting optimal conditions offer a standard basis for evaluating LiDAR cleaning performance and may help improve cleaning efficiency and maintenance strategies.

31 December 2017 in Journal of Korean Society of Transportation
Verified
Journal Article
Open access
JJJeong Ah Jang
Jeong Ah Jang
HLHyunmi Lee
Hyunmi Lee
KCKeechoo Choi
Keechoo Choi