Optical flow estimation from event-based cameras and spiking neural networks

Event-based cameras are raising interest within the computer vision community. These sensors operate with asynchronous pixels, emitting events, or “spikes”, when the luminance change at a given pixel since the last event surpasses a certain threshold. Thanks to their inherent qualities, such as thei...

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Main Authors: Javier Cuadrado, Ulysse Rançon, Benoit R. Cottereau, Francisco Barranco, Timothée Masquelier
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-05-01
Series:Frontiers in Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnins.2023.1160034/full
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author Javier Cuadrado
Ulysse Rançon
Benoit R. Cottereau
Benoit R. Cottereau
Francisco Barranco
Timothée Masquelier
author_facet Javier Cuadrado
Ulysse Rançon
Benoit R. Cottereau
Benoit R. Cottereau
Francisco Barranco
Timothée Masquelier
author_sort Javier Cuadrado
collection DOAJ
description Event-based cameras are raising interest within the computer vision community. These sensors operate with asynchronous pixels, emitting events, or “spikes”, when the luminance change at a given pixel since the last event surpasses a certain threshold. Thanks to their inherent qualities, such as their low power consumption, low latency, and high dynamic range, they seem particularly tailored to applications with challenging temporal constraints and safety requirements. Event-based sensors are an excellent fit for Spiking Neural Networks (SNNs), since the coupling of an asynchronous sensor with neuromorphic hardware can yield real-time systems with minimal power requirements. In this work, we seek to develop one such system, using both event sensor data from the DSEC dataset and spiking neural networks to estimate optical flow for driving scenarios. We propose a U-Net-like SNN which, after supervised training, is able to make dense optical flow estimations. To do so, we encourage both minimal norm for the error vector and minimal angle between ground-truth and predicted flow, training our model with back-propagation using a surrogate gradient. In addition, the use of 3d convolutions allows us to capture the dynamic nature of the data by increasing the temporal receptive fields. Upsampling after each decoding stage ensures that each decoder's output contributes to the final estimation. Thanks to separable convolutions, we have been able to develop a light model (when compared to competitors) that can nonetheless yield reasonably accurate optical flow estimates.
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spelling doaj.art-8436b69982584f8e80ba185b1d5fd3072023-05-11T11:22:18ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2023-05-011710.3389/fnins.2023.11600341160034Optical flow estimation from event-based cameras and spiking neural networksJavier Cuadrado0Ulysse Rançon1Benoit R. Cottereau2Benoit R. Cottereau3Francisco Barranco4Timothée Masquelier5CerCo UMR 5549, CNRS – Université Toulouse III, Toulouse, FranceCerCo UMR 5549, CNRS – Université Toulouse III, Toulouse, FranceCerCo UMR 5549, CNRS – Université Toulouse III, Toulouse, FranceIPAL, CNRS IRL 2955, Singapore, SingaporeDepartment of Computer Engineering, Automatics and Robotics, CITIC, University of Granada, Granada, SpainCerCo UMR 5549, CNRS – Université Toulouse III, Toulouse, FranceEvent-based cameras are raising interest within the computer vision community. These sensors operate with asynchronous pixels, emitting events, or “spikes”, when the luminance change at a given pixel since the last event surpasses a certain threshold. Thanks to their inherent qualities, such as their low power consumption, low latency, and high dynamic range, they seem particularly tailored to applications with challenging temporal constraints and safety requirements. Event-based sensors are an excellent fit for Spiking Neural Networks (SNNs), since the coupling of an asynchronous sensor with neuromorphic hardware can yield real-time systems with minimal power requirements. In this work, we seek to develop one such system, using both event sensor data from the DSEC dataset and spiking neural networks to estimate optical flow for driving scenarios. We propose a U-Net-like SNN which, after supervised training, is able to make dense optical flow estimations. To do so, we encourage both minimal norm for the error vector and minimal angle between ground-truth and predicted flow, training our model with back-propagation using a surrogate gradient. In addition, the use of 3d convolutions allows us to capture the dynamic nature of the data by increasing the temporal receptive fields. Upsampling after each decoding stage ensures that each decoder's output contributes to the final estimation. Thanks to separable convolutions, we have been able to develop a light model (when compared to competitors) that can nonetheless yield reasonably accurate optical flow estimates.https://www.frontiersin.org/articles/10.3389/fnins.2023.1160034/fulloptical flowevent visionspiking neural networksneuromorphic computingedge AI
spellingShingle Javier Cuadrado
Ulysse Rançon
Benoit R. Cottereau
Benoit R. Cottereau
Francisco Barranco
Timothée Masquelier
Optical flow estimation from event-based cameras and spiking neural networks
Frontiers in Neuroscience
optical flow
event vision
spiking neural networks
neuromorphic computing
edge AI
title Optical flow estimation from event-based cameras and spiking neural networks
title_full Optical flow estimation from event-based cameras and spiking neural networks
title_fullStr Optical flow estimation from event-based cameras and spiking neural networks
title_full_unstemmed Optical flow estimation from event-based cameras and spiking neural networks
title_short Optical flow estimation from event-based cameras and spiking neural networks
title_sort optical flow estimation from event based cameras and spiking neural networks
topic optical flow
event vision
spiking neural networks
neuromorphic computing
edge AI
url https://www.frontiersin.org/articles/10.3389/fnins.2023.1160034/full
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AT benoitrcottereau opticalflowestimationfromeventbasedcamerasandspikingneuralnetworks
AT franciscobarranco opticalflowestimationfromeventbasedcamerasandspikingneuralnetworks
AT timotheemasquelier opticalflowestimationfromeventbasedcamerasandspikingneuralnetworks