Application of Geometric Polarization to Invariance Properties in Bistatic Scattering

Bistatic polarimetric radars provide target properties which just one monostatic system can not reveal. Moreover, augmentation of monostatic systems through the provision of bistatic receive-only stations can be a cheap way to increase the amount of remote sensing data. However, bistatic scattering needs to be investigated in order to properly define target properties such as symmetries and invariance, especially regarding choices of polarization basis. In this paper we discuss how the geometric theory of polarization, in which the geometry of the Poincaré sphere is directly related to 3-D geometry of space rather than the 2-D geometry of the wavefront plane, can be used to reduce the ambiguities in the interpretation of data. We also show how in the coherent case a complex scalar invariant can be determined irrespective of the basis combinations

The road surveying system of the federal highway research institute – a performance evaluation of road segmentation algorithms

The construction of highways and federal roadways is subject to many restrictions and designing rules. The focus is on safety, comfort and smooth driving. Unfortunately, the planning information for roadways and their real constitution, course and their number of lanes and lane widths is often unsure or not available. Due to digital map databases of roads raised much interest during the last years and became one major cornerstone of innovative Advanced Driving Assistance Systems (ADASs), the demand for accurate and detailed road information increases considerably. Within this project a measurement system for collecting high accurate road data was developed. This paper gives an overview about the sensor configuration within the measurement vehicle, introduces the implemented algorithms and shows some applications implemented in the post processing platform. The aim is to recover the origin parametric description of the roadway and the performance of the measurement system is being evaluated against several original road construction information

TOF-LIDAR signal processing using the CFAR detector

In recent years, the lidar sensor has been receiving greater attention as being one of the prospective sensors for future intelligent vehicles. In order to enable advanced applications in a variety of road environments, it has become more important to detect various objects at a wider distance. Therefore, in this research we have focused on lidar signal processing to detect low signal-to-noise ratio (SNR) targets and proposed a higher sensitive detector. The detector is based on the constant false alarm rate (CFAR) processing framework in which an additional functionality of adaptive intensity integration is incorporated. Fundamental results through static experiments have shown a significant advantage in the detection performance in comparison to a conventional detector with constant thresholding

Geometrical representation of a monochromatic electromagnetic wave using the tangential vector approach

The aim of this work is to develop a coherent polarimetric model and to find a geometrical description of a monochromatic wave. The spinor form of the electrical field, its links to the coherency matrix and the Poincare' sphere are introduced with the aim to obtain a geometrical representation of the spinor. It consists, from the "polarization point of view", on the polarization vector and a tangential plane to the Poincare' sphere where it is possible to visualize the zero phase

Local Dynamic Map als modulares Software Framework für Fahrerassistenzsysteme: Local Dynamic Map als modulares Software Framework fürFahrerassistenzsysteme

Moderne Fahrerassistenzsysteme basieren auf der Verarbeitung von Informationen, welche durch die Umfeldwahrnehmung mit unterschiedlicher Sensorik erfolgt. Neben den Informationen aus dem eigenen Fahrzeug ergeben sich durch unterschiedliche Kommunikationsmöglichkeiten (Car2Car, Car2X, ...) erweiterte Umfeldwahrnehmungen (siehe Abb. 1). Diese Daten gilt es aufbereitet und zielorientiert einer Anwendung zur Verfügung zu stellen, was mit Hilfe einer Local Dynamic Map (LDM) erfüllt werden kann. Die vorliegende Veröffentlichung beschreibt den Aufbau, Verwendungszweck und Eigenschaften einer entwickelten LDM und geht auf einige Applikationen ein, die mit Hilfe dieser realisiert wurden

Multi-view point cloud fusion for LiDAR based cooperative environment detection

A key component for automated driving is 360&deg; environment detection. The recognition capabilities of modern sensors are always limited to their direct field of view. In urban areas a lot of objects occlude important areas of interest. The information captured by another sensor from another perspective could solve such occluded situations. Furthermore, the capabilities to detect and classify various objects in the surrounding can be improved by taking multiple views into account. <br><br> In order to combine the data of two sensors into one coordinate system, a rigid transformation matrix has to be derived. The accuracy of modern e.g. satellite based relative pose estimation systems is not sufficient to guarantee a suitable alignment. Therefore, a registration based approach is used in this work which aligns the captured environment data of two sensors from different positions. Thus their relative pose estimation obtained by traditional methods is improved and the data can be fused. <br><br> To support this we present an approach which utilizes the uncertainty information of modern tracking systems to determine the possible field of view of the other sensor. Furthermore, it is estimated which parts of the captured data is directly visible to both, taking occlusion and shadowing effects into account. Afterwards a registration method, based on the iterative closest point (ICP) algorithm, is applied to that data in order to get an accurate alignment. <br><br> The contribution of the presented approch to the achievable accuracy is shown with the help of ground truth data from a LiDAR simulation within a 3-D crossroad model. Results show that a two dimensional position and heading estimation is sufficient to initialize a successful 3-D registration process. Furthermore it is shown which initial spatial alignment is necessary to obtain suitable registration results

Improving pedestrian detection using MPEG-7 descriptors

During the last decade, modern Pedestrian Detection Systems made massive use of the steadily growing numbers of high-performance image acquisition sensors. Within our naturalistic driving environment, a lot of different and heterogeneous scenes occur that are caused by varying illumination and weather conditions. Unfortunately, current systems do not work properly under these hardened conditions. The aim of this article is to investigate and evaluate observed video scenes from an open source dataset by using various image features in order to create a basis for robust and more accurate object detection

Potential of coherent decompositions in SAR polarimetry and interferometry

A comparative study has indicated that coherent decompositions may have high potential in applications using fully polarimetric and interferometric SAR data, as an alternative or supplement to standard non-coherent techniques developed during the last decade. One important reason for this is that the coherent techniques are better able to benefit from the coherent nature of the underlying data and scattering mechanisms. By avoiding averaging at the first processing stage, the coherent techniques can extract target features that may otherwise be lost in the early averaging process. On the other hand, averaging is indeed important in most cases for obtaining stable and reliable end results

Automatisierter Strassenverkehr. Teilvorhaben: Kolonnenfahrt und Durchsatzoptimierung im Strassenverkehr (Elektronisches Auge - AVDB). Phase 1 Abschlussbericht

Available from TIB Hannover: F98B1971+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman