References of "Schroeder, Udo"
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See detailWidely Distributed Radar Imaging: Unmediated ADMM Based Approach
Murtada, Ahmed Abdelnaser Elsayed UL; Hu, Ruizhi UL; Mysore Rama Rao, Bhavani Shankar UL et al

in IEEE Journal of Selected Topics in Signal Processing (2022)

This paper presents a novel approach to reconstruct a unique image of an observed scene via synthetic apertures (SA) generated by employing widely distributed radar sensors. The problem is posed as a ... [more ▼]

This paper presents a novel approach to reconstruct a unique image of an observed scene via synthetic apertures (SA) generated by employing widely distributed radar sensors. The problem is posed as a constrained optimization problem in which the global image which represents the aggregate view of the sensors is a decision variable. While the problem is designed to promote a sparse solution for the global image, it is constrained such that a relationship with local images that can be reconstructed using the measurements at each sensor is respected. Two problem formulations are introduced by stipulating two different establishments of that relationship. The proposed formulations are designed according to consensus ADMM (CADMM) and sharing ADMM (SADMM), and their solutions are provided accordingly as iterative algorithms. We drive the explicit variable updates for each algorithm in addition to the recommended scheme for hybrid parallel implementation on the distributed sensors and a central processing unit. Our algorithms are validated and their performance is evaluated by exploiting the Civilian Vehicles Dome dataset to realize different scenarios of practical relevance. Experimental results show the effectiveness of the proposed algorithms, especially in cases with limited measurements. [less ▲]

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See detailContactless radar-based breathing monitoring of premature infants in the neonatal intensive care unit
Tedgue Beltrao, Gabriel UL; Stutz, Regine; Hornberger, Franziska et al

in Scientific Reports (2022), 12(1), 1--15

Vital sign monitoring systems are essential in the care of hospitalized neonates. Due to the immaturity of their organs and immune system, premature infants require continuous monitoring of their vital ... [more ▼]

Vital sign monitoring systems are essential in the care of hospitalized neonates. Due to the immaturity of their organs and immune system, premature infants require continuous monitoring of their vital parameters and sensors need to be directly attached to their fragile skin. Besides mobility restrictions and stress, these sensors often cause skin irritation and may lead to pressure necrosis. In this work, we show that a contactless radar-based approach is viable for breathing monitoring in the Neonatal intensive care unit (NICU). For the first time, different scenarios common to the NICU daily routine are investigated, and the challenges of monitoring in a real clinical setup are addressed through different contributions in the signal processing framework. Rather than just discarding measurements under strong interference, we present a novel random body movement mitigation technique based on the time-frequency decomposition of the recovered signal. In addition, we propose a simple and accurate frequency estimator which explores the harmonic structure of the breathing signal. As a result, the proposed radar-based solution is able to provide reliable breathing frequency estimation, which is close to the reference cabled device values most of the time. Our findings shed light on the strengths and limitations of this technology and lay the foundation for future studies toward a completely contactless solution for vital signs monitoring. [less ▲]

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See detailNonlinear Least Squares Estimation for Breathing Monitoring Using FMCW Radars
Tedgue Beltrao, Gabriel UL; Alaeekerahroodi, Mohammad UL; Schroeder, Udo et al

in 2021 18th Eur. Radar Conf. (2022)

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See detailStatistical Performance Analysis of Radar-Based Vital-Sign Processing Techniques
Tedgue Beltrao, Gabriel UL; Alaeekerahroodi, Mohammad UL; Schroeder, Udo et al

Scientific Conference (2022)

Radar-based vital-sign monitoring provides several advantages over standard methodologies. Despite the huge amount of recent work, the preference for particular technique(s) is in debt, due to lack of a ... [more ▼]

Radar-based vital-sign monitoring provides several advantages over standard methodologies. Despite the huge amount of recent work, the preference for particular technique(s) is in debt, due to lack of a formal comparison between them. In addition, collection of real data is a time-consuming process and therefore most of the proposed solutions are only evaluated under very limited scenarios. In this paper we present a simulation framework and a selection of results which allow easy performance comparison between radar-based vital-sign processing techniques. The proposed simulation tool scans over multiple breathing and heartbeat frequencies, and the combined effects along the entire signal processing chain can be analyzed, for different combinations of scenarios and techniques. The results have shown specific limitations for each method, thus indicating a need for proper selection based on operating conditions. In addition, while breathing estimation performance is only limited by noise, heartbeat estimation is limited by the presence of breathing harmonics and, despite promising results at specific breathing/heartbeat frequencies, the presented methods fail to fully mitigate this type of interference in all scenarios. [less ▲]

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See detailAdaptive Nonlinear Least Squares Framework for Contactless Vital Sign Monitoring
Tedgue Beltrao, Gabriel UL; Alves Martins, Wallace UL; Mysore Rama Rao, Bhavani Shankar UL et al

in IEEE Transactions on Microwave Theory and Techniques (2022)

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See detailAccelerated Consensus ADMM for Widely Distributed Radar Imaging
Murtada, Ahmed Abdelnaser Elsayed UL; Mysore Rama Rao, Bhavani Shankar UL; Hu, Ruizhi UL et al

in 2022 IEEE Radar Conference (RadarConf22) Proceedings (2022)

Widely distributed radar systems are expected to enhance radar imaging performance due to their ability to capture diverse spatial scattering proprieties. Optimization-based sub-aperture imaging methods ... [more ▼]

Widely distributed radar systems are expected to enhance radar imaging performance due to their ability to capture diverse spatial scattering proprieties. Optimization-based sub-aperture imaging methods are used to adopt the isotropic scattering assumption within a narrow angular extent and reconstruct the scene image by fusing sub-aperture images. A previously proposed method based on consensus alternating direction method of multipliers (CADMM) provides a joint reconstruction of sub-aperture images along with a global image that represents the anisotropic scene. In this paper, we propose a modified version of CADMM which features lower complexity and faster convergence. By gradually learning the scene support during the iterative reconstruction, our proposed algorithm focuses on the image portion that contains the scattering targets and updates the sub-images accordingly. It also reduces the communication cost between the distributed sensors which need to exchange local image updates during CADMM iterations. [less ▲]

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See detailEfficient Radar Imaging Using Partially Synchronized Distributed Sensors
Murtada, Ahmed Abdelnaser Elsayed UL; Hu, Ruizhi UL; Alaeekerahroodi, Mohammad UL et al

in 2021 IEEE Radar Conference (RadarConf21), Atlanta, GA, USA May 2021 (2021)

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See detailJoint Waveform/Receiver Design for Vital-Sign Detection in Signal-Dependent Interference
Tedgue Beltrao, Gabriel UL; Alaeekerahroodi, Mohammad UL; Schroeder, Udo et al

in Proceedings of the 2020 IEEE Radar Conference (RadarConf20), Florence, Italy, 2020 (2020)

This paper presents the joint design of discrete slow-time radar waveform and receive filter, with the aim of enhancing the Signal to Interference and Noise Ratio (SINR) in phase coded radar systems for ... [more ▼]

This paper presents the joint design of discrete slow-time radar waveform and receive filter, with the aim of enhancing the Signal to Interference and Noise Ratio (SINR) in phase coded radar systems for vital-sign monitoring. Towards this, we consider maximizing the SINR at the input of the vital-sign estimation block, when transmitting hardware efficient Mary Phase Shift Keying (MPSK) sequences. This multi-variable and non-convex optimization problem is efficiently solved based on a Minimum Variance Distortionless Response (MVDR) filter, with the Coordinate Descent (CD) approach for the sequence optimization, and the obtained results have shown attractive interference suppression capabilities, even for the simple binary case. [less ▲]

Detailed reference viewed: 129 (9 UL)