Microwave and Millimeter Wave NDE – Focus on Aerospace Applications

About Dr. Zoughi's Webinar

Microwave and millimeter-wave signals span frequency ranges of ~300 MHz-30 GHz and 30 GHz-300 GHz, corresponding to wavelength ranges of 1000-10 mm and 10-1 mm, respectively. Signals at these frequencies readily penetrate inside of dielectric materials and composites and interact with their inner structures. The intrinsic nature of the interaction of these signals with material media, the relatively small wavelengths and wide bandwidths associated with these signals provide for the inspection of a variety of materials for their properties and presence of flaws with high sensitivity. Furthermore, availability of robust and advanced electromagnetic models and modeling tools, and improved imaging techniques rendering real-time, high-resolution (3D) images of materials and structures are specific and attractive features that have brought tremendous visibility and viability for microwave and millimeter wave nondestructive evaluation (NDE) techniques and applications. In addition, the diversity of composite materials and structures, used in the space and aerospace industries, has brought upon significant growth in the utility of these methods. Currently, these methods are capable of addressing critical NDE issues related to: i) characterization of multi-phase material and mixture composition, ii) evaluation of surface-breaking crack particularly those under thick non-conductive coatings, iii) inspection of complex layered composite structures, iv) detection of corrosion and pitting under coatings, v) inspection of aircraft radome, and vi) inspection and imaging of thermal protective layers, to name a few. Finally, advances in innovative hardware designs, development of easy-to-use software packages, and availability of commercial off-the-shelf (COTS) components and systems, have resulted in inspection systems that are affordable, portable, field-deployable and easy-to-use. Consequently, microwave and millimeter wave NDE methods are no longer to be considered as “emerging technologies” since they have been undergoing significant maturation over the past 3+ decades. This presentation provides an overview of these techniques, along with illustration of several typical examples of inspection focused on aerospace inspection.

Multi-Sensor Perception and Data Fusion for Autonomous Vehicles

About Dr. Watzenig's Webinar

Autonomous driving is seen as one of the pivotal technologies that considerably will shape our society and will influence future transportation modes and quality of life, altering the face of mobility as we experience it by today. Many benefits are expected ranging from reduced accidents, optimized traffic, improved comfort, social inclusion, lower emissions, and better road utilization due to efficient integration of private and public transport. Autonomous driving is a highly complex sensing and control problem. State-of-the-art vehicles include many different compositions of sensors including radar, cameras, and lidar. Each sensor provides specific information about the environment at varying levels and has an inherent uncertainty and accuracy measure. Sensors are the key to the perception of the outside world in an autonomous driving system and whose cooperation performance directly determines the safety of such vehicles. Beyond the sensors needed for perception, the control system needs some basic measure of its position in space and its surrounding reality. Real-time capable sensor processing techniques used to integrate this information have to manage the propagation of their inaccuracies, fuse information to reduce the uncertainties and, ultimately, offer levels of confidence in the produced representations that can be then used for safe navigation decisions and actions.

Sensor fusion overcomes the drawbacks of current sensor technology by combining information from many independent sources of limited accuracy and reliability. This makes the system less vulnerable to random and systematic failures of a single component. Multi-source information fusion avoids the perceptual limitations and uncertainties of a single sensor and forms a more comprehensive perception and recognition of the environment including static and dynamic objects. In general, multi-sensor data fusion can achieve an increased classification accuracy of objects, improved state estimation accuracy, improved robustness for instance in adverse weather conditions, an increased availability, and an enlarged field of view. Emerging applications such as autonomous driving systems that are in direct contact and interact with the real world, require reliable and accurate information about their environment in real-time.

The talk will include:

• A basic introduction to the sense-plan-act challenges of autonomous vehicles
• Introduction to the most common state-of-the-art sensors used in autonomous driving (radar, camera, lidar, GPS, odometry, vehicle-2-x) in terms of benefits and disadvantages along with mathematical models of these sensors
• Overview of different sensor data fusion taxonomies as well as different ways to model the environment (dynamic object tracking vs. occupancy grid) in the Bayesian framework including uncertainty quantification
• Exploiting potential problems of sensor data fusion, e.g. data association, outlier treatment, anomalies, bias, correlation, or out-of-sequence measurements when using Bayesian approaches

The main purpose of this talk is to get an overview of the current autonomous driving challenges, to understand and to apply appropriate methods for real-time multi-sensor data fusion, and how to perform decision making under uncertainties for safe and reliable autonomous driving.