7.1 A 4-tap 3.5 μm 1.2 Mpixel Indirect Time-of-Flight CMOS Image Sensor with Peak Current Mitigation and Multi-User Interference Cancellation

Keel, Min-Sun; Kim, Dae‐Yun; Kim, Yeomyung; Bae, Myunghan; Ki, Myoungoh; Chung, Bumsik; Son, Sooho; Lee, Ho-Yong; Jo, Heeyoung; Shin, Seung-Chul; Hong, Sunjoo; An, Jaeil; Kwon, Yonghun; Seo, Sungyoung; Cho, Sunghyuck; Kim, Young-Chan; Jin, Yu; Oh, Youngsun; Kim, Yitae; Ahn, Jin-Hyun; Koh, Kyoungmin; Park, Yongin

doi:10.1109/isscc42613.2021.9365854

Cited by 29 publications

(17 citation statements)

References 3 publications

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“…Figure 2 shows a typical 4-tap pixel operated with a modulated short-pulse (SP) light. There are numerous designs for demodulators [3]- [5][13] [15][22]- [30]. Figure 2(b) depicts a demodulator that employs a lateral-drift pinned photodiode with three n-type doping layers and transfer gates for gating signal photoelectrons and draining unwanted electrons.…”

Section: A Principle Of Htof Pixelsmentioning

confidence: 99%

“…The quantum efficiency QE is defined at 940nm. A recent development of iTOF image sensors using BSI technology shows the QE of 38% at 940nm [5]. Three kinds of QE, 20% (conservative), 40% (state-of-the-art) and 60% (future target) are assumed to know how the improvement of QE gives an impact in the depth precision.…”

Section: A Tof Camera and Sensor Specificationsmentioning

confidence: 99%

“…A long-range binarymode dTOF imager with high ambient light tolerance and 160k pixels has been reported [18], but it is once excluded from the comparison with the present work, because the imager has a very special spec (the depth resolution of 7.5m). Highresolution (VGA or >1M) iTOF image sensors have recently been reported [3]- [5][15] [16]. Their maximum tolerance to ambient light is 25klux, and their maximum range is 4.2 meters.…”

Section: Introductionmentioning

confidence: 99%

“…INSE the introduction of the concept of solid-state time-offlight (TOF) range cameras using CCD image sensor technology [1] [2] in the mid-1990s, TOF cameras using solidstate TOF image sensors have been expected to be used for 3D imaging in a variety of application fields. TOF image sensors using demodulation pixels, referred to indirect TOF or iTOF image sensors, implemented with CMOS image sensor technology is a good solution for high range-image resolution TOF cameras [3]- [5]. Currently, iTOF image sensors are suitable for indoor or outdoor use, with a range of up to several meters under moderate ambient light conditions.…”

Section: Introductionmentioning

confidence: 99%

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Hybrid Time-of-Flight Image Sensors for Middle-Range Outdoor Applications

Kawahito

Yasutomi

Mars

2022

IEEE Open J. Solid-State Circuits Soc.

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This paper introduces a new series of time-of-flight (TOF) range image sensors that can be used for outdoor middlerange (10m to 100m) applications by employing a small duty-cycle modulated light pulse with a relatively high optical peak power. This set of TOF sensors is referred to here as a hybrid TOF (hTOF) image sensor. The hTOF image sensor is based on the indirect TOF measurement principle but simultaneously uses the direct TOF concept for coarse measurements. Compared to conventional indirect TOF image sensors for outdoor middlerange applications, the hTOF image sensor has a distinct advantage due to the reduction of capturing ambient light charge. To show the potential of the hTOF image sensor for outdoor middle-range operation, a model of estimating distance precision of hTOF image sensors is built and applied it by using possible sensor specifications to estimate the distance precision of the hTOF range camera in 10m, 20m and 40m measurements under the ambient-light condition of 100klux and its feasibility is discussed. In outdoor 10m-range measurements, the advantage of hTOF image sensors compared to the conventional indirect TOF image sensors is discussed by considering the amount of captured ambient-light charge in pixels.

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Section: A Principle Of Htof Pixelsmentioning

confidence: 99%

Section: A Tof Camera and Sensor Specificationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hybrid Time-of-Flight Image Sensors for Middle-Range Outdoor Applications

Kawahito

Yasutomi

Mars

2022

IEEE Open J. Solid-State Circuits Soc.

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“…If a model can be developed to further utilize the point cloud generated by the ToF camera to take more subtle movements such as head rotation/tilting into consideration, it would expand the types of motion artifacts that the CVSM system can compensate. At the same time, efforts are made to develop an indirect ToF camera with a higher resolution and frame rate [39].…”

Section: Future Improvementsmentioning

confidence: 99%

Contactless Vital Sign Monitoring System for Heart and Respiratory Rate Measurements with Motion Compensation Using a Near-Infrared Time-of-Flight Camera

et al. 2021

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This study describes a contactless vital sign monitoring (CVSM) system capable of measuring heart rate (HR) and respiration rate (RR) using a low-power, indirect time-of-flight (ToF) camera. The system takes advantage of both the active infrared illumination as well as the additional depth information from the ToF camera to compensate for the motion-induced artifacts during the HR measurements. The depth information captures how the user is moving with respect to the camera and, therefore, can be used to differentiate where the intensity change in the raw signal is from the underlying heartbeat or motion. Moreover, from the depth information, the system can acquire respiration rate by directly measuring the motion of the chest wall during breathing. We also conducted a pilot human study using this system with 29 participants of different demographics such as age, gender, and skin color. Our study shows that with depth-based motion compensation, the success rate (system measurement within 10% of reference) of HR measurements increases to 75%, as compared to 35% when motion compensation is not used. The mean HR deviation from the reference also drops from 21 BPM to −6.25 BPM when we apply the depth-based motion compensation. In terms of the RR measurement, our system shows a mean deviation of 1.7 BPM from the reference measurement. The pilot human study shows the system performance is independent of skin color but weakly dependent on gender and age.

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Ultra-High-Speed Charge-Domain Temporally Compressive CMOS Image Sensors

Kagawa,

Nagahara

2023

Coded Optical Imaging

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7.1 A 4-tap 3.5 μm 1.2 Mpixel Indirect Time-of-Flight CMOS Image Sensor with Peak Current Mitigation and Multi-User Interference Cancellation

Cited by 29 publications

References 3 publications

Hybrid Time-of-Flight Image Sensors for Middle-Range Outdoor Applications

Hybrid Time-of-Flight Image Sensors for Middle-Range Outdoor Applications

Contactless Vital Sign Monitoring System for Heart and Respiratory Rate Measurements with Motion Compensation Using a Near-Infrared Time-of-Flight Camera

Ultra-High-Speed Charge-Domain Temporally Compressive CMOS Image Sensors

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