TOF range image sensor using a range-shift technique

Sawada, Tomonari; Ito, Kana; Nakayama, M.; Kawahito, Shoji

doi:10.1109/icsens.2008.4716706

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…The short-pulse width leads to better depth precision but decreases the measurable range. To extend the measurable range, a range-shift technique using multiple frames is presented [21]. In the technique, the trigger delay of the light source is varied in several frames, which is equivalent to shifting of the measurable range.…”

Section: Modulation Methods In Indirect Tofmentioning

confidence: 99%

Lock-in Pixel Based Time-of-Flight Range Imagers: An Overview

Yasutomi

Kawahito

2022

IEICE Trans. Electron.

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Time-of-flight (TOF) range imaging is a promising technology for various applications such as touchless control, augmented reality interface, and automotive. The TOF range imagers are classified into two methods: direct TOF with single photo avalanche diodes and indirect TOF with lock-in pixels. The indirect TOF range imagers have advantages in terms of a high spatial resolution and high depth precision because their pixels are simple and can handle many photons at one time. This paper reviews and discusses principal lock-in pixels reported both in the past and present, including circuit-based and charge-modulator-based lock-in pixels. In addition, key technologies that include enhancing sensitivity and background suppression techniques are also discussed.

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Section: Modulation Methods In Indirect Tofmentioning

confidence: 99%

Lock-in Pixel Based Time-of-Flight Range Imagers: An Overview

Yasutomi

Kawahito

2022

IEICE Trans. Electron.

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“…In contrast, the short pulse (SP) modulation prepared by 4-tap 1-drain iToF pixel has been reported to have better ambient light tolerance due to the concentrated light energy from the emitter [15], [16]. In addition, the range-shifted technique can be adopted to increase the number of timewindows (TWs) for long-range detection [11], [17].…”

Section: Sensor Implementation a Indirect-tof Using 4-tap Short Pulse...mentioning

confidence: 99%

A 134×132 4-Tap CMOS Indirect Time-of-Flight Range Imager Using In-Pixel Memory Array With 10 Kfps High-Speed Mode and High Precision Mode

Kuo

Kuroda

2024

IEEE J. Solid-State Circuits

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“…By using the TOF measurement with the impulse photocurrent response, the measurable range is limited to several centimeters [22], [26]. However, the limited measurable range can be expanded by using a range-shift technique in pulse-based TOF measurements [29], [35]. In the technique, the measurable range is shifted by controlling a trigger of the light source, and the measurable range can be expanded by using multiple frames.…”

Section: Tof Measurement With Three-tap Lock-in Pixelmentioning

confidence: 99%

A Sub-100 $\mu$ m-Range-Resolution Time-of-Flight Range Image Sensor With Three-Tap Lock-In Pixels, Non-Overlapping Gate Clock, and Reference Plane Sampling

Yasutomi

Yushi

Kagawa

et al. 2019

IEEE J. Solid-State Circuits

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This paper aims to propose a time-of-flight (TOF) range imager with high range resolution in the sub-100 µm range. The range imager employs a TOF measurement technique that uses an impulse photocurrent response and a three-tap lock-in pixel based on the lateral electric field modulation. To reduce the clock skew of the gating clocks, a column-parallel digital delaylocked loop (DLL) with a dual clock tree is implemented with a short calibration time of approximately 42 µs. A non-overlapping gate clock generation included in the skew calibration circuit effectively suppresses the photogenerated-charge partitioning for reduced nonlinearity for distance measurements. Reference plane sampling (RPS) is proposed to reduce low-frequency jitter that limits the range resolution in the light-pulse trigger. In this technique, a reference pixel array is embedded in the same focal plane of the main pixel array to sample and cancel the correlated jitter in the light trigger. The prototype range imager with 192 × 4 effective pixels is implemented in a 0.11-µm CMOS image sensor technology. Using the RPS, a range resolution of 64 µm rms has been achieved, corresponding to a 430-fs time resolution with a 25-mm range. The range resolution has a large column-to-column deviation due to the jitter induced by the column-parallel gating buffers. In noisy columns, jitter that acts as random telegraph noise (RTN) is observed. Index Terms-CMOS image sensor (CIS), delay-locked loop (DLL)-based skew calibration, high range resolution, lateral electric field modulator (LEFM), lock-in pixel, non-overlapping gate clock, photogenerated-charge partitioning, range imaging, reference plane sampling (RPS), skew calibration, time-offlight (TOF).

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TOF range image sensor using a range-shift technique

Cited by 6 publications

References 2 publications

Lock-in Pixel Based Time-of-Flight Range Imagers: An Overview

Lock-in Pixel Based Time-of-Flight Range Imagers: An Overview

A 134×132 4-Tap CMOS Indirect Time-of-Flight Range Imager Using In-Pixel Memory Array With 10 Kfps High-Speed Mode and High Precision Mode

A Sub-100 $\mu$ m-Range-Resolution Time-of-Flight Range Image Sensor With Three-Tap Lock-In Pixels, Non-Overlapping Gate Clock, and Reference Plane Sampling

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