Yun Hee Lee

Dr. Yun Hee Lee

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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4 January 2025 in Applied Sciences
Verified
Journal Article
Open access
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YLYun Hee Lee
Yun Hee Lee
MPManbok Park
Manbok Park
This paper focuses on a method of rearview camera-based blind-spot detection and a lane change assistance system for autonomous vehicles, utilizing a convolutional neural network and lane detection. In this study, we propose a method for providing real-time warnings to autonomous vehicles and drivers regarding collision risks during lane-changing maneuvers. We propose a method for lane detection to delineate the area for blind-spot detection and for measuring time to collision—both utilized to ascertain the vehicle’s location and compensate for vertical vibrations caused by vehicle movement. The lane detection method uses edge detection on an input image to extract lane markings by employing edge pairs consisting of positive and negative edges. Lanes were extracted through third-polynomial fitting of the extracted lane markings, with each lane marking being tracked using the results from the previous frame detections. Using the vanishing point where the two lanes converge, the camera calibration information is updated to compensate for the vertical vibrations caused by vehicle movement. Additionally, the proposed method utilized YOLOv9 for object detection, leveraging lane information to define the region of interest (ROI) and detect small-sized objects. The object detection achieved a precision of 90.2% and a recall of 82.8%. The detected object information was subsequently used to calculate the collision risk. A collision risk assessment was performed for various objects using a three-level collision warning system that adapts to the relative speed of obstacles. The proposed method demonstrated a performance of 11.64 fps with an execution time of 85.87 ms. It provides real-time warnings to both drivers and autonomous vehicles regarding potential collisions with detected objects.

22 October 2020 in IEEE Access
Verified
Journal Article
Open access
YLYun Hee Lee
Yun Hee Lee
WKWhoi-Yul Kim
Whoi-Yul Kim
We introduce a method for the efficient calibration of around-view-monitoring (AVM) cameras. Particularly, we introduce two situations that require calibration because of the characteristics of AVM cameras: a situation wherein cameras are shipped from the manufacturing line and another situation wherein some cameras are distorted during operation and need recalibration. In this study, the calibration method for shipped cameras is defined as the factory mode and that for recalibration is defined as the service mode. In the factory mode, two circular patterns placed at a regular distance are used to ensure the maximum accuracy while requiring minimum calibration. In the service mode, as a recalibration method, we developed a robust method that considers various environments using parallel parking lines that can be easily installed in general service centers. In the factory mode, we confirmed that the AVM-camera-calibration error was within 5.66 cm when the two circular patterns were located at a certain distance within a certain range. However, in the service mode, we achieved camera movement angle error equal to or less than 0.1° using the parking-line-detection result.

4 May 2022 in Electronics
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Journal Article
Open access
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YLYun Hee Lee
Yun Hee Lee
MPMin-Ki Park
Min-Ki Park
MPManbok Park
Manbok Park
Automotive companies have studied the development of lane support systems in order to secure the Euro New Car Assessment Program (NCAP)’s high score. A front camera module is applied with safety assistance systems in an intelligent vehicle. However, the front camera module has limitations in terms of backlight conditions, entering or exiting tunnels, and night driving because of lower image quality. In this paper, we propose an integrated camera with dual light sensor for improving lane detection performance under the worst conditions. We include a new algorithm to enhance image data quality and improve edge detection and lane tracking using illumination information. We evaluate the tests under various conditions on a real road. These tests are performed on 728 km of road (under various external situations and lane types) for false alarm rates. The experimental results show that the system is promising in terms of reliability, enhancement, and improvements.

14 December 2021 in Applied Sciences
Verified
Journal Article
Open access
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YLYun Hee Lee
Yun Hee Lee
MPManbok Park
Manbok Park
This paper introduces an automatic parking method using an around view monitoring system. In this method, parking lines are extracted from the camera images, and a route to a targeted parking slot is created. The vehicle then tracks this route to park. The proposed method extracts lines from images using a line filter and a Hough transform, and it uses a convolutional neural network to robustly extract parking lines from the environment. In addition, a parking path consisting of curved and straight sections is created and used to control the vehicle. Perpendicular, angle, and parallel parking paths can be created; however, parking control is applied according to the shape of each parking slot. The results of our experiments confirm that the proposed method has an average offset of 10.3 cm and an average heading angle error of 0.94°.

26 January 2026 in Electronics
Verified
Journal Article
Open access
PDF file
YLYun Hee Lee
Yun Hee Lee
MPManbok Park
Manbok Park
This paper presents a real-time pedestrian situation detection framework for autonomous mobility platforms. The proposed approach extracts pedestrians from images acquired by a camera mounted on an autonomous mobility system, classifies their postures, tracks their trajectories, and subsequently detects pedestrian situations. A convolutional neural network (CNN) is employed for pedestrian detection and posture classification, where the YOLOv12 model is fine-tuned via transfer learning for this purpose. To improve detection and classification performance, a region of interest (ROI) is defined using camera calibration data, enabling robust detection of small-scale pedestrians over long distances. Using a custom-labeled dataset, the proposed method achieves a precision of 96.6% and a recall of 97.0% for pedestrian detection and posture classification. The detected pedestrians are tracked using the DeepSORT algorithm, and their situations are inferred through a rule-based analysis module. Experimental results demonstrate that the proposed system operates at an execution speed of 58.11 ms per frame, corresponding to 17.2 fps, thereby satisfying the real-time requirements for autonomous mobility applications. These results confirm that the proposed framework enables reliable real-time pedestrian extraction and situation awareness in real-world autonomous mobility environments.