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20 results on '"Lee, Hoyong"'

6. An Indirect Time-of-Flight CMOS Image Sensor Achieving Sub-ms Motion Lagging and 60fps Depth Image from On-chip ISP

Author

Park, Jiheon, primary, Kim, Daeyun, additional, Lee, Hoyong, additional, Shin, Seung-Chul, additional, Ki, Myoungoh, additional, Chung, Bumsik, additional, Bae, Myunghan, additional, Kye, Myeonggyun, additional, Ahn, Jonghan, additional, Song, Inho, additional, Lee, Sunhwa, additional, An, Jaeil, additional, Hwang, Il-Pyeong, additional, An, Taemin, additional, Jin, Young-Gu, additional, Kim, Youngchan, additional, Oh, Youngsun, additional, Ko, Juhyun, additional, Lee, Haechang, additional, and Yim, JoonSeo, additional

Published
2023
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8. Effective Feature-Based Downward-Facing Monocular Visual Odometry

Author

Lee, Hoyong, Lee, Hakjun, Kwak, Inveom, Sung, Chiwon, and Han, Soohee

Abstract

To achieve accurate pose estimation for robots in industrial applications and services, this brief proposes an effective feature-based downward-facing monocular visual odometry technology that uses an affordable sensor system and a systematic optimization approach. To extract more effective features simply and efficiently from images of the ground, even for small mobile systems, the proposed visual odometry system is designed in a lightweight and cost-effective manner; we used an easily available LED, a single-channel time-of-flight (ToF) sensor, and a monocular camera. From the extracted features, the potentially irrelevant ones are removed in advance, using a masking algorithm and measured velocity. This enhances feature efficiency and reduces the computational burden. Finally, the optimal pose estimate is explicitly obtained by solving a nonconvex optimization problem, to make the best use of the features. The experiments’ results show that our proposed method improves feature tracking ability and pose estimation accuracy.

Published
2024
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14. Suitability of Various Lidar and Radar Sensors for Application in Robotics: A Measurable Capability Comparison

Author

Gim, Haeyeon, Baek, Seungmin, Park, Jeongki, Lee, Hoyong, Sung, Chiwon, Kim, Kyung-Tae, and Han, Soohee

Abstract

Lidar and radar sensors are widely used to obtain depth information for various applications in the field of robotics, such as navigation [1], collision avoidance [2], surveillance [3], and map generation [4]. These two sensors are becoming increasingly popular as perception systems for autonomous mobile robots. However, as a result of their versatility and popularity, lidar and radar sensors come in a variety of specifications, sizes, and prices. Consequently, it has become essential to quantitatively evaluate these two sensors from various situational perspectives. This is required for a comprehensive selection of the most appropriate sensors or combinations thereof for the target applications.

Published
2023
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19. A 1.2-Mpixel Indirect Time-of-Flight Image Sensor With 4-Tap 3.5-μm Pixels for Peak Current Mitigation and Multi-User Interference Cancellation

Author

Keel, Min-Sun, primary, Kim, Daeyun, additional, Kim, Yeomyung, additional, Bae, Myunghan, additional, Ki, Myoungoh, additional, Chung, Bumsik, additional, Son, Sooho, additional, Lee, Hoyong, additional, Shin, Seung-Chul, additional, Kye, Myeonggyun, additional, An, Jaeil, additional, Kwon, Yonghun, additional, Seo, Sungyoung, additional, Cho, Sunghyuck, additional, Kim, Youngchan, additional, Jin, Young-Gu, additional, Oh, Youngsun, additional, Kim, Yitae, additional, Ahn, Jungchak, additional, and Lee, Jesuk, additional

Published
2021
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20. A 1.2-Mpixel Indirect Time-of-Flight Image Sensor With 4-Tap 3.5- μ m Pixels for Peak Current Mitigation and Multi-User Interference Cancellation.

Author

Keel, Min-Sun, Kim, Daeyun, Kim, Yeomyung, Bae, Myunghan, Ki, Myoungoh, Chung, Bumsik, Son, Sooho, Lee, Hoyong, Shin, Seung-Chul, Kye, Myeonggyun, An, Jaeil, Kwon, Yonghun, Seo, Sungyoung, Cho, Sunghyuck, Kim, Youngchan, Jin, Young-Gu, Oh, Youngsun, Kim, Yitae, Ahn, Jungchak, and Lee, Jesuk

Subjects
IMAGE sensors, CMOS image sensors, PHASE noise, QUANTUM efficiency, IMAGE color analysis
Abstract

A 1.2-Mpixel indirect time-of-flight (ToF) CMOS image sensor is presented to lower peak current and to cancel out multi-user interference. The proposed 4-tap 3.5- $\mu \text{m}$ demodulation pixel is optimally designed to improve quantum efficiency (QE) and demodulation contrast (DC). A new “multiple-interleaving” scheme is proposed to reduce the peak current and self-compensate fixed-pattern phase noise (FPPN) with the minimal side effect of DC imbalance. To cancel out interference from the other ToF sensors, a multi-user interference cancellation (MUIC) scheme based on pseudorandom modulation is adopted. From the measurement results, we achieve a high QE of 38% at 940 nm and a high DC of 96% and 80% at 100- and 200-MHz modulation frequencies, respectively. With the superior pixel performance, the depth noise of <0.92% and <0.3% is achieved at the full and 2 $\times $ 2 binning modes, respectively. The multiple-interleaving scheme suppresses the peak current to less than 0.9 A and removes the column FPPN with constant DC for the whole pixel array. The proposed MUIC proves that at least two interferers can be successfully rejected. The sensor chip is fabricated in a two-stack process with 65 nm for the top die and 65 nm for the bottom die. [ABSTRACT FROM AUTHOR]

Published
2021
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