318 research outputs found
A low-cost through-the-wall FMCW radar for stand-off operation and activity detection
In this paper we present a new through-wall (TW) FMCW radar system. The architecture of the radar enables both high sensitivity and range resolutions of <1.5 m. Moreover, the radar employs moving target indication (MTI) signal processing to remove the problematic primary wall reflection, allowing higher signal-to- noise and signal-to-interference ratios, which can be traded-off for increased operational stand-off. The TW radar operates at 5.8 GHz with a 200 MHz bandwidth. Its dual-frequency design minimises interference from signal leakage, and permits a baseband output after deramping which is digitized using an inexpensive 24-bit off-the-shelf sound card. The system is therefore an order of magnitude lower in cost than competitor ultrawideband (UWB) TW systems. The high sensitivity afforded by this wide dynamic range has allowed us to develop a wall removal technique whereby high-order digital filters provide a flexible means of MTI filtering based on the phases of the returned echoes. Experimental data demonstrates through-wall detection of individuals and groups of people in various scenarios. Target positions were located to within ±1.25 m in range, allowing us distinguish between two closely separated targets. Furthermore, at 8.5 m standoff, our wall removal technique can recover target responses that would have otherwise been masked by the primary wall reflection, thus increasing the stand-off capability of the radar. Using phase processing, our experimental data also reveals a clear difference in the micro-Doppler signatures across various types of everyday actions
RSS-Net: Weakly-Supervised Multi-Class Semantic Segmentation with FMCW Radar
This paper presents an efficient annotation procedure and an application
thereof to end-to-end, rich semantic segmentation of the sensed environment
using FMCW scanning radar. We advocate radar over the traditional sensors used
for this task as it operates at longer ranges and is substantially more robust
to adverse weather and illumination conditions. We avoid laborious manual
labelling by exploiting the largest radar-focused urban autonomy dataset
collected to date, correlating radar scans with RGB cameras and LiDAR sensors,
for which semantic segmentation is an already consolidated procedure. The
training procedure leverages a state-of-the-art natural image segmentation
system which is publicly available and as such, in contrast to previous
approaches, allows for the production of copious labels for the radar stream by
incorporating four camera and two LiDAR streams. Additionally, the losses are
computed taking into account labels to the radar sensor horizon by accumulating
LiDAR returns along a pose-chain ahead and behind of the current vehicle
position. Finally, we present the network with multi-channel radar scan inputs
in order to deal with ephemeral and dynamic scene objects.Comment: submitted to IEEE Intelligent Vehicles Symposium (IV) 202
Few-Shot User-Definable Radar-Based Hand Gesture Recognition at the Edge
This work was supported in part by ITEA3 Unleash Potentials in Simulation (UPSIM) by the German Federal Ministry of Education and Research (BMBF) under Project 19006, in part by the Austrian Research Promotion Agency (FFG), in part by the Rijksdienst voor Ondernemend Nederland (Rvo), and in part by the Innovation Fund Denmark (IFD).Technological advances and scalability are leading Human-Computer Interaction (HCI) to evolve towards intuitive forms, such as through gesture recognition. Among the various interaction strategies, radar-based recognition is emerging as a touchless, privacy-secure, and versatile solution in different environmental conditions. Classical radar-based gesture HCI solutions involve deep learning but require training on large and varied datasets to achieve robust prediction. Innovative self-learning algorithms can help tackling this problem by recognizing patterns and adapt from similar contexts. Yet, such approaches are often computationally expensive and hardly integrable into hardware-constrained solutions. In this paper, we present a gesture recognition algorithm which is easily adaptable to new users and contexts. We exploit an optimization-based meta-learning approach to enable gesture recognition in learning sequences. This method targets at learning the best possible initialization of the model parameters, simplifying training on new contexts when small amounts of data are available. The reduction in computational cost is achieved by processing the radar sensed data of gestures in the form of time maps, to minimize the input data size. This approach enables the adaptation of simple convolutional neural network (CNN) to new hand poses, thus easing the integration of the model into a hardware-constrained platform. Moreover, the use of a Variational Autoencoders (VAE) to reduce the gestures' dimensionality leads to a model size decrease of an order of magnitude and to half of the required adaptation time. The proposed framework, deployed on the Intel(R) Neural Compute Stick 2 (NCS 2), leads to an average accuracy of around 84% for unseen gestures when only one example per class is utilized at training time. The accuracy increases up to 92.6% and 94.2% when three and five samples per class are used.Federal Ministry of Education & Research (BMBF) 19006Austrian Research Promotion Agency (FFG)Rijksdienst voor Ondernemend Nederland (Rvo)Innovation Fund Denmark (IFD
Milli-RIO: Ego-Motion Estimation with Low-Cost Millimetre-Wave Radar
Robust indoor ego-motion estimation has attracted significant interest in the
last decades due to the fast-growing demand for location-based services in
indoor environments. Among various solutions, frequency-modulated
continuous-wave (FMCW) radar sensors in millimeter-wave (MMWave) spectrum are
gaining more prominence due to their intrinsic advantages such as penetration
capability and high accuracy. Single-chip low-cost MMWave radar as an emerging
technology provides an alternative and complementary solution for robust
ego-motion estimation, making it feasible in resource-constrained platforms
thanks to low-power consumption and easy system integration. In this paper, we
introduce Milli-RIO, an MMWave radar-based solution making use of a single-chip
low-cost radar and inertial measurement unit sensor to estimate
six-degrees-of-freedom ego-motion of a moving radar. Detailed quantitative and
qualitative evaluations prove that the proposed method achieves precisions on
the order of few centimeters for indoor localization tasks.Comment: Submitted to IEEE Sensors, 9page
Aprendizagem automática aplicada à deteção de pessoas baseada em radar
The present dissertation describes the development and implementation of a
radar-based system with the purpose of being able to detect people amidst
other objects that are moving in an indoor scenario. The detection methods
implemented exploit radar data that is processed by a system that includes the
data acquisition, the pre-processing of the data, the feature extraction, and the
application of these data to machine learning models specifically designed to
attain the objective of target classification.
Beyond the basic theoretical research necessary for its sucessful development,
the work contamplates an important component of software development
and experimental tests. Among others, the following topics were covered
in this dissertation: the study of radar working principles and hardware; radar
signal processing; techniques of clutter removal, feature exctraction, and data
clustering applied to radar signals; implementation and hyperparameter tuning
of machine learning classification systems; study of multi-target detection and
tracking methods.
The people detection application was tested in different indoor scenarios that
include a static radar and a radar dynamically deployed by a mobile robot. This
application can be executed in real time and perform multiple target detection
and classification using basic clustering and tracking algorithms. A study of
the effects of the detection of multiple targets in the performance of the application,
as well as an assessment of the efficiency of the different classification
methods is presented.
The envisaged applications of the proposed detection system include intrusion
detection in indoor environments and acquisition of anonymized data for
people tracking and counting in public spaces such as hospitals and schools.A presente dissertação descreve o desenvolvimento e implementação de um
sistema baseado em radar que tem como objetivo detetar e distinguir pessoas
de outros objetos que se movem num ambiente interior. Os métodos de deteção
e distinção exploram os dados de radar que são processados por um
sistema que abrange a aquisição e pré-processamento dos dados, a extração
de características, e a aplicação desses dados a modelos de aprendizagem
automática especificamente desenhados para atingir o objetivo de classificação
de alvos.
Além do estudo da teoria básica de radar para o desenvolvimento bem sucedido
desta dissertação, este trabalho contempla uma componente importante
de desenvolvimento de software e testes experimentais. Entre outros,
os seguintes tópicos foram abordados nesta dissertação: o estudo dos
princípios básicos do funcionamento do radar e do seu equipamento; processamento
de sinal do radar; técnicas de remoção de ruído, extração de
características, e segmentação de dados aplicada ao sinal de radar; implementação
e calibração de hiper-parâmetros dos modelos de aprendizagem
automática para sistemas de classificação; estudo de métodos de deteção e
seguimento de múltiplos alvos.
A aplicação para deteção de pessoas foi testada em diferentes cenários interiores
que incluem o radar estático ou transportado por um robot móvel.
Esta aplicação pode ser executada em tempo real e realizar deteção e classificação
de múltiplos alvos usando algoritmos básicos de segmentação e
seguimento. O estudo do impacto da deteção de múltiplos alvos no funcionamento
da aplicação é apresentado, bem como a avaliação da eficiência dos
diferentes métodos de classificação usados.
As possíveis aplicações do sistema de deteção proposto incluem a deteção
de intrusão em ambientes interiores e aquisição de dados anónimos para
seguimento e contagem de pessoas em espaços públicos tais como hospitais
ou escolas.Mestrado em Engenharia de Computadores e Telemátic
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