Refine
Document Type
- Conference Proceeding (9)
- Article (reviewed) (4)
- Article (unreviewed) (4)
- Bachelor Thesis (2)
- Book (2)
- Contribution to a Periodical (2)
- Part of a Book (1)
- Master's Thesis (1)
Conference Type
- Konferenzartikel (9)
Keywords
- Optik (3)
- Photonik (3)
- Radar (3)
- UWB radars (2)
- catheter ablation (2)
- imaging algorithms (2)
- medical imaging (2)
- microwave (2)
- scattering measurements (2)
- Angle of Arrival (1)
- Anomalie (1)
- Astronomie (1)
- Automotive Radar (1)
- Autopilot (1)
- BISp (1)
- Bauteil (1)
- Bodenradar (1)
- Bowtie antenna (1)
- CFD (1)
- CNN (1)
- Convolutional neural networks (1)
- Elektromagnetische Reflexionsmethode (1)
- Erzählung (1)
- Farbe (1)
- Flugregelung (1)
- Flächenflieger (1)
- GPR (1)
- Gehirn (1)
- Gewebe (1)
- Ground penetrating radar (1)
- Hand (1)
- Hinderniserkennung (1)
- Hybridtechnik (1)
- Lidarsensorik (1)
- Linse (1)
- Mean Square Error (1)
- Medizin (1)
- Medizingeschichte (1)
- Mikrocontroller (1)
- Mumie (1)
- Paganini, Niccolò (1)
- Radarsensorik (1)
- Raman-Spektroskopie (1)
- Schlafstörung (1)
- Sensortechnik (1)
- Skisprung (1)
- Spektralanalyse (1)
- Spektroskopie (1)
- Sport (1)
- Tomografie (1)
- Trauma (1)
- Unmanned Aerial Vehicles (1)
- Wirbelsäule (1)
- curb (1)
- detection (1)
- ground penetrating radar (1)
- height estimation (1)
- millimeter-wave (1)
- multipath (1)
- parking (1)
- skin cancer (1)
- skin cancer detection (1)
- thickness estimation (1)
Institute
- IUAS - Institute for Unmanned Aerial Systems (25) (remove)
Open Access
- Closed (6)
- Closed Access (6)
- Open Access (5)
- Bronze (1)
Investigation on Bowtie Antennas Operating at Very Low Frequencies for Ground Penetrating Radar
(2023)
The efficiency of Ground Penetrating Radar (GPR) systems significantly depends on the antenna performance as the signal has to propagate through lossy and inhomogeneous media. GPR antennas should have a low operating frequency for greater penetration depth, high gain and efficiency to increase the receiving power and should be compact and lightweight for ease of GPR surveying. In this paper, two different designs of Bowtie antennas operating at very low frequencies are proposed and analyzed.
A method for evaluating skin cancer detection based on millimeter-wave technologies is presented. For this purpose, the relative permittivities are calculated using the effective medium theory for the benign and cancerous lesion, considering the change in water content between them. These calculated relative permittivities are further used for the simulation and evaluation of skin cancer detection using a substrate-integrated waveguide probe. A difference in the simulated scattering parameters S 11 of up to 13dB between healthy and cancerous skin can be determined in the best-case.
Skin cancer detection proves to be complicated and highly dependent on the examiner’s skills. Millimeter-wave technologies seem to be a promising aid for the detection of skin cancer. The different water content of the skin area affected by cancer compared to healthy skin changes its reflective property. Due to limited available resources on the dielectric properties of skin cancer, especially in comparison to surrounding healthy skin, accurate simulations and evaluations are quite challenging. Therefore, comparing different results for different approaches and starting points can be difficult. In this paper, the Effective Medium Theory is applied to model skin cancer, which provides permittivity values dependent on the water content.
AI-based Ground Penetrating Radar Signal Processing for Thickness Estimation of Subsurface Layers
(2023)
This thesis focuses on the estimation of subsurface layer thickness using Ground Penetrating Radar (GPR) A-scan and B-scan data through the application of neural networks. The objective is to develop accurate models capable of estimating the thickness of up to two subsurface layers.
Two different approaches are explored for processing the A-scan data. In the first approach, A-scans are compressed using Principal Component Analysis (PCA), and a regression feedforward neural network is employed to estimate the layers’ thicknesses. The second approach utilizes a regression one-dimensional Convolutional Neural Network (1-D CNN) for the same purpose. Comparative analysis reveals that the second approach yields superior results in terms of accuracy.
Subsequently, the proposed 1-D CNN architecture is adapted and evaluated for Step Frequency Continuous Wave (SFCW) radar, expanding its applicability to this type of radar system. The effectiveness of the proposed network in estimating subsurface layer thickness for SFCW radar is demonstrated.
Furthermore, the thesis investigates the utilization of GPR B-scan images as input data for subsurface layer thickness estimation. A regression CNN is employed for this purpose, although the results achieved are not as promising as those obtained with the 1-D CNN using A-scan data. This disparity is attributed to the limited availability of B-scan data, as B-scan generation is a resource-intensive process.
Konzeption und Evaluierung eines Trainings-Windkanals für den spezifischen Einsatz im Skisprung
(2022)
In automotive parking scenario, where the curb shall be detected and classified to be traversable or not, radars play an important role. There are different approaches already proposed in other works to estimate the target height. This paper assesses and compares two methods. The first is based on Angle of Arrival (AoA) estimation of input signals of multiple antennas using the Multiple-Input-Multiple-Output (MIMO) principle. The second method uses the geometry in multipath propagation of the radar echo signal for one antenna input. In this work a modified method of calculation of the curb height based on the second method is proposed. The theory of approach is mathematically proved and effectiveness is demonstrated by evaluation of measurements with a 77 GHz Frequency Modulated Continuous Wave (FMCW) radar. In order to evaluate the performance of the introduced method the mean square error (MSE) is used in the proposed scenario. This method, using only one antenna input, produced up to 3.4 times better results for curb height detection in comparison with former methods.
In this study, various imaging algorithms for the localization of objects have been investigated. Therefore, an Ultra-Wideband (UWB) radar based experimental setup with a circular antenna array is designed as part of this work. This concept could be particularly useful in microwave medical imaging applications. In order to validate its applicability in microwave imaging, different imaging algorithms have been evaluated and compared by means of our experimental setup. Accurate imaging results have been achieved with our system under multiple test-scenarios.
In this study, an approach to a microwave-based radar system for the localization of objects has been proposed. This could be particularly useful in microwave imaging applications such as cardiac catheter detection. An experimental system is defined and realized with the selection of an appropriate antenna design. Hardware control functions and different imaging algorithms are implemented as well. The functionality of this measurement setup has been analyzed considering multiple testscenarios and it is proved to be capable of locating multiple objects as well as expanded objects.
UAVs (engl. Unmanned Aerial Vehicles) sind in den vergangenen Jahren auch außerhalb militärischer und wissenschaftlicher Nutzung beliebter geworden. Für autonome Fluganwendungen ist die Überwachung der Umgebung zwingend notwendig. In dieser Arbeit wird ein experimenteller Ansatz zur Hinderniserkennung mit Radar- und Lidarsensorik präsentiert. Dieser setzt sich aus der Kollisionsvermeidung der Flugsteuerung px4, einem Nvidia Jetson TX2 als Flugbegleitcomputer und den Sensoren Slamtec RPLidar A2M6 und Texas Instruments AWR1443 Radar zusammen. Insgesamt wurden drei verschiedene Hardwarekomponenten getestet. Zur Auswertung der Versuche wird eine durch Python OS-unabhängige Auswertesoftware entwickelt und implementiert. Die Versuchsplanung setzt sich aus drei Versuchen mit jeweils fünf in Geometrie und Textur unterschiedlichen Hindernissen zusammen. Die Versuchsergebnisse zeigen, dass der eingesetzte Lidar gegenüber dem Radar Vorteile auf kurze Distanz aufweist. Zur Reproduzierbarkeit von Experimenten auf kurzer Distanz wird die Entwicklung eines fixen Messaufbaus empfohlen.