This document describes a multi-camera time-of-flight imaging system that uses multiple synchronized cameras and light sources. It allows control over modulation signals to capture dynamic scenes and extract depth, velocity and non-line-of-sight motion information. The system architecture uses a direct digital synthesis chip to generate programmable modulation signals, synchronized signal conditioning circuits and a real-time controller to coordinate image capture across multiple time-of-flight cameras. It aims to enable applications like phased array imaging, simultaneous Doppler velocity capture and detecting motion behind scattering media.
Multi-camera Time-of-Flight Systems | SIGGRAPH 2016
1. Computational Imaging with
Multi-Camera Time-of-Flight Systems
Felix Heide*1,2Shikhar Shrestha*1 Wolfgang Heidrich2,3 Gordon Wetzstein1
2University of British Columbia 3KAUST1Stanford University
www.computationalimaging.org
* joint first authors
2. Time-of-Flight Imaging
Kinect for Xbox One Google Tango Phone
Direct Sampling Transient Imaging
[Velten et al. 2013]
Google Self-Driving Car
Facial capture in VR
[Li et al. 2015]
Correlation Transient Imaging
[Heide et al. 2013]
3. Multi-Camera ToF System
• Multiple Camera/Sources
• Phased Array
• Control over modulation
• Extensible
• Reproducible
16. Multi-Camera ToF System – Key System Components
Direct Digital Synthesis (DDS)
Ch 0
Ch 1
Ch 2
Ch 3
- Programmable Frequency/Phase
- Resolution : 0.12 Hz/0.02°
- Range : 0-200 MHz/0-360°
- Control over SPI
• Custom Board for End-to-End
Signal Conditioning
• Combines a High Speed
Comparator with Exposure
Gating IC
• Interfaces Directly with TI ToF
Camera
Signal Conditioning Circuitry
ToF Daughter BoardAD9959
Real-Time Controller
STMF4 Discovery Board
• Controller responsible for
triggering frames, controlling
waveform generation and
synchronization
• Runs low-level firmware based
on an interrupt driven state
machine architecture
17. Multi-Camera ToF System – System Workflow
Signal Conditioning Circuitry
(Now on ToF Daughter Board)
DDS Block
MCU Host
Real-Time Controller
Ref. Signal
(Now uses SAW Oscillator
@ 5—MHz)
PC
ToF Cameras
18. Multi-Camera ToF System – System Workflow
Signal Conditioning Circuitry
(Now on ToF Daughter Board)
DDS Block
Ref. Signal
(Now uses SAW Oscillator
@ 500 MHz)
Configure Modulation Parameters
ToF Cameras
19. Multi-Camera ToF System – System Workflow
Signal Conditioning Circuitry
(Now on ToF Daughter Board)
DDS Block
Ref. Signal
(Now uses SAW Oscillator
@ 5—MHz)
Configure Camera Registers
20. Multi-Camera ToF System – System Workflow
Signal Conditioning Circuitry
(Now on ToF Daughter Board)
DDS Block
Ref. Signal
(Now uses SAW Oscillator
@ 5—MHz)
Initiate a Frame
21. Multi-Camera ToF System – System Workflow
DDS Block
Ref. Signal
(Now uses SAW Oscillator
@ 5—MHz)
Start of Micro-Exposure/Quad