Time-of-flight (ToF) imaging has emerged as a vital technology in machine vision and sensing, expanding into applications such as augmented and virtual reality, gaming, robotics, autonomous driving, autofocus, and facial recognition on smartphones and laptops. ToF technology determines the distance to an object within the detection range by emitting a light source and measuring the time it takes to return. This round-trip time determines the object{\textquoteright}s distance, with different sensing technologies employing distinct methods to determine this time.For ToF applications, developing sensors with high image resolution, low power consumption, and the ability to function reliably in high ambient light conditions is desirable. This dissertation presents the development of a novel single-photon avalanche diode (SPAD)-based pixel called Correlation-Assisted Direct Time-of-Flight (CA-dToF), designed for in-pixel ambient light suppression and characterized by low power consumption and a scalable pixel structure. The CA-dToF pixel uses a laser pulse correlated with two orthogonal sinusoidal signals as inputs to two switched capacitor channels, which average out detected ambient light while accumulating the laser pulse round-trip time.To gain insights into CA-dToF pixel operation, both Python simulation and analytical modeling were developed. Two generations of the CA-dToF pixel were designed and characterized, with the second-generation pixel achieving the first operational performance under high ambient light conditions. The second-generation CA-dToF pixel was validated under various lighting conditions and pixel design variations. Additionally, noise sources within the pixel implementation were analyzed, and potential solutions were proposed.Finally, the dissertation is concluded by discussing the environmental challenges affecting CA-dToF operation.
Morsy, A 2025, 'A novel approach to depth-sense imaging using correlation-assisted direct time-of-flight', Vrije Universiteit Brussel.
Morsy, A. (2025). A novel approach to depth-sense imaging using correlation-assisted direct time-of-flight. [PhD Thesis, Vrije Universiteit Brussel].
@phdthesis{601abf5f9fdc48b4b1c244e9c9926511,
title = "A novel approach to depth-sense imaging using correlation-assisted direct time-of-flight",
abstract = "Time-of-flight (ToF) imaging has emerged as a vital technology in machine vision and sensing, expanding into applications such as augmented and virtual reality, gaming, robotics, autonomous driving, autofocus, and facial recognition on smartphones and laptops. ToF technology determines the distance to an object within the detection range by emitting a light source and measuring the time it takes to return. This round-trip time determines the object{\textquoteright}s distance, with different sensing technologies employing distinct methods to determine this time.For ToF applications, developing sensors with high image resolution, low power consumption, and the ability to function reliably in high ambient light conditions is desirable. This dissertation presents the development of a novel single-photon avalanche diode (SPAD)-based pixel called Correlation-Assisted Direct Time-of-Flight (CA-dToF), designed for in-pixel ambient light suppression and characterized by low power consumption and a scalable pixel structure. The CA-dToF pixel uses a laser pulse correlated with two orthogonal sinusoidal signals as inputs to two switched capacitor channels, which average out detected ambient light while accumulating the laser pulse round-trip time.To gain insights into CA-dToF pixel operation, both Python simulation and analytical modeling were developed. Two generations of the CA-dToF pixel were designed and characterized, with the second-generation pixel achieving the first operational performance under high ambient light conditions. The second-generation CA-dToF pixel was validated under various lighting conditions and pixel design variations. Additionally, noise sources within the pixel implementation were analyzed, and potential solutions were proposed.Finally, the dissertation is concluded by discussing the environmental challenges affecting CA-dToF operation.",
author = "Ayman Morsy",
year = "2025",
language = "English",
school = "Vrije Universiteit Brussel",
}