A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network

Light detection and ranging (LiDAR) technology, a cutting-edge advancement in mobile applications, presents a myriad of compelling use cases, including enhancing low-light photography, capturing and sharing 3D images of fascinating objects, and elevating the overall augmented reality (AR) experience...

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Main Authors: Jier Wang, Jie Li, Yifan Wu, Hengwei Yu, Lebei Cui, Miao Sun, Patrick Yin Chiang
Format: Article
Language:English
Published: MDPI AG 2023-08-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/15/6927
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author Jier Wang
Jie Li
Yifan Wu
Hengwei Yu
Lebei Cui
Miao Sun
Patrick Yin Chiang
author_facet Jier Wang
Jie Li
Yifan Wu
Hengwei Yu
Lebei Cui
Miao Sun
Patrick Yin Chiang
author_sort Jier Wang
collection DOAJ
description Light detection and ranging (LiDAR) technology, a cutting-edge advancement in mobile applications, presents a myriad of compelling use cases, including enhancing low-light photography, capturing and sharing 3D images of fascinating objects, and elevating the overall augmented reality (AR) experience. However, its widespread adoption has been hindered by the prohibitive costs and substantial power consumption associated with its implementation in mobile devices. To surmount these obstacles, this paper proposes a low-power, low-cost, single-photon avalanche detector (SPAD)-based system-on-chip (SoC) which packages the microlens arrays (MLAs) and a lightweight RGB-guided sparse depth imaging completion neural network for 3D LiDAR imaging. The proposed SoC integrates an 8 × 8 SPAD macropixel array with time-to-digital converters (TDCs) and a charge pump, fabricated using a 180 nm bipolar-CMOS-DMOS (BCD) process. Initially, the primary function of this SoC was limited to serving as a ranging sensor. A random MLA-based homogenizing diffuser efficiently transforms Gaussian beams into flat-topped beams with a 45° field of view (FOV), enabling flash projection at the transmitter. To further enhance resolution and broaden application possibilities, a lightweight neural network employing RGB-guided sparse depth complementation is proposed, enabling a substantial expansion of image resolution from 8 × 8 to quarter video graphics array level (QVGA; 256 × 256). Experimental results demonstrate the effectiveness and stability of the hardware encompassing the SoC and optical system, as well as the lightweight features and accuracy of the algorithmic neural network. The state-of-the-art SoC-neural network solution offers a promising and inspiring foundation for developing consumer-level 3D imaging applications on mobile devices.
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spelling doaj.art-4ba53bf663584b04b68052881c3874b32023-11-18T23:36:20ZengMDPI AGSensors1424-82202023-08-012315692710.3390/s23156927A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural NetworkJier Wang0Jie Li1Yifan Wu2Hengwei Yu3Lebei Cui4Miao Sun5Patrick Yin Chiang6State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, ChinaState Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, ChinaCollege of Electronics and Information Engineering, Tongji University, Shanghai 201804, ChinaState Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, ChinaState Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, ChinaState Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, ChinaState Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, ChinaLight detection and ranging (LiDAR) technology, a cutting-edge advancement in mobile applications, presents a myriad of compelling use cases, including enhancing low-light photography, capturing and sharing 3D images of fascinating objects, and elevating the overall augmented reality (AR) experience. However, its widespread adoption has been hindered by the prohibitive costs and substantial power consumption associated with its implementation in mobile devices. To surmount these obstacles, this paper proposes a low-power, low-cost, single-photon avalanche detector (SPAD)-based system-on-chip (SoC) which packages the microlens arrays (MLAs) and a lightweight RGB-guided sparse depth imaging completion neural network for 3D LiDAR imaging. The proposed SoC integrates an 8 × 8 SPAD macropixel array with time-to-digital converters (TDCs) and a charge pump, fabricated using a 180 nm bipolar-CMOS-DMOS (BCD) process. Initially, the primary function of this SoC was limited to serving as a ranging sensor. A random MLA-based homogenizing diffuser efficiently transforms Gaussian beams into flat-topped beams with a 45° field of view (FOV), enabling flash projection at the transmitter. To further enhance resolution and broaden application possibilities, a lightweight neural network employing RGB-guided sparse depth complementation is proposed, enabling a substantial expansion of image resolution from 8 × 8 to quarter video graphics array level (QVGA; 256 × 256). Experimental results demonstrate the effectiveness and stability of the hardware encompassing the SoC and optical system, as well as the lightweight features and accuracy of the algorithmic neural network. The state-of-the-art SoC-neural network solution offers a promising and inspiring foundation for developing consumer-level 3D imaging applications on mobile devices.https://www.mdpi.com/1424-8220/23/15/6927LiDAR3D imagingsystem-on-chipmicrolens arrayneural networkRGB-guided
spellingShingle Jier Wang
Jie Li
Yifan Wu
Hengwei Yu
Lebei Cui
Miao Sun
Patrick Yin Chiang
A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network
Sensors
LiDAR
3D imaging
system-on-chip
microlens array
neural network
RGB-guided
title A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network
title_full A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network
title_fullStr A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network
title_full_unstemmed A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network
title_short A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network
title_sort 256 256 lidar imaging system based on a 200 mw spad based soc with microlens array and lightweight rgb guided depth completion neural network
topic LiDAR
3D imaging
system-on-chip
microlens array
neural network
RGB-guided
url https://www.mdpi.com/1424-8220/23/15/6927
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