1,018 research outputs found
Event-based Vision: A Survey
Event cameras are bio-inspired sensors that differ from conventional frame
cameras: Instead of capturing images at a fixed rate, they asynchronously
measure per-pixel brightness changes, and output a stream of events that encode
the time, location and sign of the brightness changes. Event cameras offer
attractive properties compared to traditional cameras: high temporal resolution
(in the order of microseconds), very high dynamic range (140 dB vs. 60 dB), low
power consumption, and high pixel bandwidth (on the order of kHz) resulting in
reduced motion blur. Hence, event cameras have a large potential for robotics
and computer vision in challenging scenarios for traditional cameras, such as
low-latency, high speed, and high dynamic range. However, novel methods are
required to process the unconventional output of these sensors in order to
unlock their potential. This paper provides a comprehensive overview of the
emerging field of event-based vision, with a focus on the applications and the
algorithms developed to unlock the outstanding properties of event cameras. We
present event cameras from their working principle, the actual sensors that are
available and the tasks that they have been used for, from low-level vision
(feature detection and tracking, optic flow, etc.) to high-level vision
(reconstruction, segmentation, recognition). We also discuss the techniques
developed to process events, including learning-based techniques, as well as
specialized processors for these novel sensors, such as spiking neural
networks. Additionally, we highlight the challenges that remain to be tackled
and the opportunities that lie ahead in the search for a more efficient,
bio-inspired way for machines to perceive and interact with the world
Real-time motor rotation frequency detection with event-based visual and spike-based auditory AER sensory integration for FPGA
Multisensory integration is commonly
used in various robotic areas to collect more
environmental information using different and
complementary types of sensors. Neuromorphic
engineers mimics biological systems behavior to
improve systems performance in solving engineering
problems with low power consumption. This work
presents a neuromorphic sensory integration scenario
for measuring the rotation frequency of a motor using
an AER DVS128 retina chip (Dynamic Vision Sensor)
and a stereo auditory system on a FPGA completely
event-based. Both of them transmit information with
Address-Event-Representation (AER). This
integration system uses a new AER monitor hardware
interface, based on a Spartan-6 FPGA that allows two
operational modes: real-time (up to 5 Mevps through
USB2.0) and data logger mode (up to 20Mevps for
33.5Mev stored in onboard DDR RAM). The sensory
integration allows reducing prediction error of the
rotation speed of the motor since audio processing
offers a concrete range of rpm, while DVS can be
much more accurate.Ministerio de Economía y Competitividad TEC2012-37868-C04-02/0
Bio-Inspired Stereo Vision Calibration for Dynamic Vision Sensors
Many advances have been made in the eld of computer vision. Several recent research trends
have focused on mimicking human vision by using a stereo vision system. In multi-camera systems, a
calibration process is usually implemented to improve the results accuracy. However, these systems generate
a large amount of data to be processed; therefore, a powerful computer is required and, in many cases,
this cannot be done in real time. Neuromorphic Engineering attempts to create bio-inspired systems that
mimic the information processing that takes place in the human brain. This information is encoded using
pulses (or spikes) and the generated systems are much simpler (in computational operations and resources),
which allows them to perform similar tasks with much lower power consumption, thus these processes
can be developed over specialized hardware with real-time processing. In this work, a bio-inspired stereovision
system is presented, where a calibration mechanism for this system is implemented and evaluated
using several tests. The result is a novel calibration technique for a neuromorphic stereo vision system,
implemented over specialized hardware (FPGA - Field-Programmable Gate Array), which allows obtaining
reduced latencies on hardware implementation for stand-alone systems, and working in real time.Ministerio de Economía y Competitividad TEC2016-77785-PMinisterio de Economía y Competitividad TIN2016-80644-
End-to-End Learning of Representations for Asynchronous Event-Based Data
Event cameras are vision sensors that record asynchronous streams of
per-pixel brightness changes, referred to as "events". They have appealing
advantages over frame-based cameras for computer vision, including high
temporal resolution, high dynamic range, and no motion blur. Due to the sparse,
non-uniform spatiotemporal layout of the event signal, pattern recognition
algorithms typically aggregate events into a grid-based representation and
subsequently process it by a standard vision pipeline, e.g., Convolutional
Neural Network (CNN). In this work, we introduce a general framework to convert
event streams into grid-based representations through a sequence of
differentiable operations. Our framework comes with two main advantages: (i)
allows learning the input event representation together with the task dedicated
network in an end to end manner, and (ii) lays out a taxonomy that unifies the
majority of extant event representations in the literature and identifies novel
ones. Empirically, we show that our approach to learning the event
representation end-to-end yields an improvement of approximately 12% on optical
flow estimation and object recognition over state-of-the-art methods.Comment: To appear at ICCV 201
Pseudo-labels for Supervised Learning on Dynamic Vision Sensor Data, Applied to Object Detection under Ego-motion
In recent years, dynamic vision sensors (DVS), also known as event-based
cameras or neuromorphic sensors, have seen increased use due to various
advantages over conventional frame-based cameras. Using principles inspired by
the retina, its high temporal resolution overcomes motion blurring, its high
dynamic range overcomes extreme illumination conditions and its low power
consumption makes it ideal for embedded systems on platforms such as drones and
self-driving cars. However, event-based data sets are scarce and labels are
even rarer for tasks such as object detection. We transferred discriminative
knowledge from a state-of-the-art frame-based convolutional neural network
(CNN) to the event-based modality via intermediate pseudo-labels, which are
used as targets for supervised learning. We show, for the first time,
event-based car detection under ego-motion in a real environment at 100 frames
per second with a test average precision of 40.3% relative to our annotated
ground truth. The event-based car detector handles motion blur and poor
illumination conditions despite not explicitly trained to do so, and even
complements frame-based CNN detectors, suggesting that it has learnt
generalized visual representations
- …