Sampling phased array

Andrey Bulavinov, Michael Kröning, Friedhelm Walte Fraunhofer Institute for Non-Destructive Testing IZFP Saarbrücken, 66123, Germany Telephone +49 (0) 681 / 9302 0 Telefax +49 (0) 681 / 9302 5901 [email protected], [email protected]. ...

In this article, we are interested in the implementation of an open-source low-level architecture (critical system) adapted to agile and easily replicable close-range remote sensing robots operating in multiple evolution domains. After reviewing the existing autopilots responding to these needs, we discuss the available hardware solutions and their limits. Then, we propose an original solution (software and hardware) that we developed to obtain a universal low-level architecture for all our exploration robots, whatever their environment of evolution, and the steps needed to make it run on our chosen family of micro-controllers: the ESP32. Finally, we present the operational results obtained on our different platforms (land, surface, submarine and air), their limits and the envisaged perspectives.

The detection of concealed weapons is one of the biggest challenges facing the security community. It has been shown that each weapon can have a unique fingerprint, which is an electromagnetic signal determined by its size, shape, and physical composition. Extracting the signature of each weapon is one of the major tasks of any detection system. This paper addresses the issue of identifying conductive objects based on their response to electromagnetic fields. A system developed at Newcastle University using a walk-through metal detector with a giant magneto-resistive sensor array to measure the spatial magnetic field is used in the study. Threat and non-threat objects have been tested. Image visualization and feature extraction of the electromagnetic field were carried out. Classification was performed using cross correlation. Promising results indicating the feasibility of using electromagnetic imaging to identify objects have been found.

The substrate/coating adhesion is a crucial parameter conditioning the quality of coating and its durability in service. For this reason, a control of the coating integrity will be of great importance especially the presence of adhesion defects. The adhesion control is usually ensured by destructive methods, such as traction, interfacial indentation, four point bending, testing scratch, etc. However, it is currently hampered by the absence of a satisfactory non-destructive technique. Among the non-destructive testing technologies widely used in the industrial field, we find X-ray diffraction, ultrasound, infrared thermography, etc. In this paper, we are interested by two methods: the ultrasound, which is becoming more efficient, especially with the emergence of phased array systems and the active infrared thermography. To that end, Ni-WC coatings are deposited on a mild steel substrate by flame thermal spray technology and used as tested material. The coating thickness is about 1.3 ...

The detection of concealed weapons is one of the biggest challenges facing the security community. It has been shown that each weapon can have a unique fingerprint, which is an electromagnetic signal determined by its size, shape, and physical composition. Extracting the signature of each weapon is one of the major tasks of any detection system. This paper addresses the issue of identifying conductive objects based on their response to electromagnetic fields. A system developed at Newcastle University using a walk-through metal detector with a giant magneto-resistive sensor array to measure the spatial magnetic field is used in the study. Threat and non-threat objects have been tested. Image visualization and feature extraction of the electromagnetic field were carried out. Classification was performed using cross correlation. Promising results indicating the feasibility of using electromagnetic imaging to identify objects have been found.

Air pollution monitoring has recently become an issue of utmost importance in our society. Despite the fact that crowdsensing approaches could be an adequate solution for urban areas, they cannot be implemented in rural environments. Instead, deploying a fleet of UAVs could be considered an acceptable alternative. Embracing this approach, this paper proposes the use of UAVs equipped with off-the-shelf sensors to perform air pollution monitoring tasks. These UAVs are guided by our proposed Pollution-driven UAV Control (PdUC) algorithm, which is based on a chemotaxis metaheuristic and a local particle swarm optimization strategy. Together, they allow automatically performing the monitoring of a specified area using UAVs. Experimental results show that, when using PdUC, an implicit priority guides the construction of pollution maps by focusing on areas where the pollutants’ concentration is higher. This way, accurate maps can be constructed in a faster manner when compared to other str...

The possibility for the application of an elastic organosilicon polymer (aquapolymer) as an immersion medium for providing a stable acoustic contact between a tested object with a rough surface and an antenna array in automated ultrasonic testing is considered. If the form of the surface is known, it can be accounted for in the C-SAFT method for the reconstruction of a reflector image using echo signals. A surface profile can be obtained by either direct measurement using a profilometer or by anal ysis of the reconstructed surface image. An algorithm for processing a surface that was reconstructed using the C-SAFT method is proposed for automatic acquisition of information on the profile of the surface. The operability of the proposed method of reflector image acquisition with consideration of the rough surface of a tested object is demonstrated in model experiments.

Increasing the inspection quality and speed is essential in manufacturing applications, especially for large structures (e.g. modern aircrafts). Traditional ultrasonic manual scanning can be comprehensive, but lacks repeatability and is time-consuming. Several robotic non-destructive testing systems have been developed in recent years. Although high inspection rates have been achieved by the use of robotic arms, there is the need to furtherly increase the inspection speeds, to cope with the current industrial demands. For systems delivering robotic ultrasonic inspection through phased array probes, the current bottleneck is given by the time required to electrically fire all elements of the phased array probes, which limits the maximum scanning speed of the automated manipulators. This paper discusses the development of a multiaperture beamforming method to focus the beam with multiple focusing points at a single firing. This work investigates this approach and the influence of different aperture excitations on the data quality. Experiments have been carried out using a 5MHz 32-element phased array probe manipulated by a KUKA robot. The results highlight the possibility to significantly improve the speed of automated inspection compared to linear beamforming, without compromising the inspection quality.

A large number of microwave sensors are available on the market today. Unfortunately, sensors of high quality are very expensive and tend to be stationary, making them unsuitable for integrating into an industrial process. Processing of microwave data is a challenging and complex task, and leads to high computational demands and increased processing time, so real-time quality control becomes virtually impossible. In this paper, we introduce a prototype system for nondestructive testing that utilizes moderately expensive continuous wave (CW) sensors. We exploit the physical phenomenon of the Doppler Effect to detect discontinuities in materials. We also propose an approach for fast measurements and data processing.

The "Sampling Phased Array" technique compared with the conventional phased array approach became very popular in the last years making use of the propagation of elementary waves (Huygens principle) generated by individual elements of the sensor array to reconstruct the composite phased array signal by high-speed numerical computation for any arbitrary, individual angle or physically possible focus depth. As the near field of each individual transducer in the array is that of a 'quasi' point source, transducer-near inspection regions are much better to inspect than in the conventional case where the near field is determined by the full aperture of the transducer array. Furthermore, the special IZFP-approach allows a very fast 3-dimensional visualization of inspection objects by combining - slice by slice - 2-dimensionally calculated SAFT-B-images to a 3-dimensional data-cube with a manifold of possible data projections for evaluation and analysis of the inspection ...

Nondestructive testing (NDT) system engineering is comprised of different technologies, primarily measurement physics, computing, electronics, mechanical engineering and automation. Significant progress in sensor physics, microelectronics and computing in the last decade will change both the quality and application of NDT. We present examples of intelligent sensor technologies and integrated, efficient computing structures for signal processing. Keywords: Sensor-on-chip, Quantum Physical Sensing Effects and efficient scheduling of Optimized Algorithms including ill-posed problems. Our first systems designed on these principles allow for high-speed imaging with real-time quantitative assessment of inspection results. Multi-sensor systems, which communicate and combine their information for smarter processing, have also been developed. These principles will contribute to the current efforts in process integrated NDT, quantitative NDT and Structural Health Monitoring (SHM). We discuss ...

Nondestructive testing (NDT) system engineering is comprised of different technologies, primarily measurement physics, computing, electronics, mechanical engineering and automation. Significant progress in sensor physics, microelectronics and computing in the last decade will change both the quality and application of NDT. We present examples of intelligent sensor technologies and integrated, efficient computing structures for signal processing. Keywords: Sensor-on-chip, Quantum Physical Sensing Effects and efficient scheduling of Optimized Algorithms including ill-posed problems. Our first systems designed on these principles allow for high-speed imaging with real-time quantitative assessment of inspection results. Multi-sensor systems, which communicate and combine their information for smarter processing, have also been developed. These principles will contribute to the current efforts in process integrated NDT, quantitative NDT and Structural Health Monitoring (SHM). We discuss ...

The substrate/coating adhesion is a crucial parameter conditioning the quality of coating and its durability in service. For this reason, a control of the coating integrity will be of great importance especially the presence of adhesion defects. The adhesion control is usually ensured by destructive methods, such as traction, interfacial indentation, four point bending, testing scratch, etc. However, it is currently hampered by the absence of a satisfactory non-destructive technique. Among the non-destructive testing technologies widely used in the industrial field, we find X-ray diffraction, ultrasound, infrared thermography, etc. In this paper, we are interested by two methods: the ultrasound, which is becoming more efficient, especially with the emergence of phased array systems and the active infrared thermography. To that end, Ni-WC coatings are deposited on a mild steel substrate by flame thermal spray technology and used as tested material. The coating thickness is about 1.3 ...

Nondestructive testing (NDT) system engineering is comprised of different technologies, primarily measurement physics, computing, electronics, mechanical engineering and automation. Significant progress in sensor physics, microelectronics and computing in the last decade will change both the quality and application of NDT. We present examples of intelligent sensor technologies and integrated, efficient computing structures for signal processing. Keywords: Sensor-on-chip, Quantum Physical Sensing Effects and efficient scheduling of Optimized Algorithms including ill-posed problems. Our first systems designed on these principles allow for high-speed imaging with real-time quantitative assessment of inspection results. Multi-sensor systems, which communicate and combine their information for smarter processing, have also been developed. These principles will contribute to the current efforts in process integrated NDT, quantitative NDT and Structural Health Monitoring (SHM). We discuss ...

The assurance of technical safety and quality of ma terials, parts and components during production and operation, along with monitoring and control of structural health processes and other scenarios, has become essential for modern high-tech industry. As a result, the market demands for NDE equipment and services are growing in respect to specific applications and fit-for-purpose equipment. Furthermore, NDT has become important for national policies directed towards the development of a national engineering infrastructure and to meet government directives. The development of industries and the use of techniques, which may cause severe dama ge in case of failure, are also subject to international cooperation and agreements. As a result, within the international framework, each nation has to assume responsibility for safe, secure and controlled technologies. These aspects prompted the establishment of NDE centers in countries with high-tech industry and installations, such as nuclear...

The "Sampling Phased Array" technique compared with the conventional phased array approach became very popular in the last years making use of the propagation of elementary waves (Huygens principle) generated by individual elements of the sensor array to reconstruct the composite phased array signal by high-speed numerical computation for any arbitrary, individual angle or physically possible focus depth. As the near field of each individual transducer in the array is that of a 'quasi' point source, transducer-near inspection regions are much better to inspect than in the conventional case where the near field is determined by the full aperture of the transducer array. Furthermore, the special IZFP-approach allows a very fast 3-dimensional visualization of inspection objects by combining - slice by slice - 2-dimensionally calculated SAFT-B-images to a 3-dimensional data-cube with a manifold of possible data projections for evaluation and analysis of the inspection ...

Unmanned Aircraft Systems (UASs), together with the miniaturisation of computers, sensors, and electronics, offer new remote sensing applications. However, there is a lack of hardware and software support to effectively develop the potential of UASs in different remote sensing applications, such as the detection of radioactive sources. This paper presents the design, development and validation of a UAS for the detection of an uncontrolled and point radioactive source. The article describes a flexible and reusable software architecture for detecting the radioactive source (NaTcO 4 , containing 99 m Tc) with a gamma-ray Cadmium Zinc Telluride (CZT) spectrometer as a proof of concept. The UAS is equipped with multichannel air-ground communications to perform missions beyond line of sight and onboard computation to process samples in real time and thus react to any anomaly detected during the mission. An ad hoc ground control station (GCS) has also been developed for the correct interpr...

To unlock the full potential of composite materials, reliable measurement methods during and after their manufacturing are required. Established measuring methods are commonly based on ultrasound or thermographic imaging techniques and offer only a limited usability. A promising alternative to the aforementioned methods are millimeterwave-based systems. It has already been demonstrated that such systems can provide a tomographic representation of composite materials, enabling the detection, localization, and classification of critical defects within the component. The tomographic millimeter-wave imaging system presented here is operating in the W band and is packaged for the operation in a manufacturing environment. For this purpose, it is enclosed by a dustproof housing and can be mounted on an industrial robot, which enables the development of an automated measurement procedure during and after the manufacturing process of composite materials. The direct integration of the measurement system into the manufacturing process allows for early-stage fault detection and classification, which is essential for the production of high-quality, high-performance, and highly reliable composite materials. Index Terms-Microwave/millimeter wave sensors, composite materials, millimeter-wave (mmW) radar, nondestructive testing, radar imaging, robot programming.

Ultrasonic testing and evaluation procedures typically depend on reference reflectors to establish detection sensitivity and evaluation of test data. Rules and regulations governing safety-related components emphasize on test procedures that assure the detectability of discontinuities at all over the component and oriented in any arbitrary direction. Existing procedures, however, do not provide information for a quantitative presentation of type and size of the detected discontinuities. To size the defects it requires additional measurements and analysis, involving complex inspection procedures and highly qualified expert personnel, are required. Furthermore, critical flaws evaluated with fracture-mechanics analysis appear much larger than comparable detectable reference reflectors. For ultrasonic testing results to become relevant input for the fracture-mechanics analysis, the ultrasonic test data must deliver high-quality flaw images that are quantifiable. For industry to use such...

The "Sampling Phased Array" technique compared with the conventional phased array approach became very popular in the last years making use of the propagation of elementary waves (Huygens principle) generated by individual elements of the sensor array to reconstruct the composite phased array signal by high-speed numerical computation for any arbitrary, individual angle or physically possible focus depth. As the near field of each individual transducer in the array is that of a 'quasi' point source, transducer-near inspection regions are much better to inspect than in the conventional case where the near field is determined by the full aperture of the transducer array. Furthermore, the special IZFP-approach allows a very fast 3-dimensional visualization of inspection objects by combining - slice by slice - 2-dimensionally calculated SAFT-B-images to a 3-dimensional data-cube with a manifold of possible data projections for evaluation and analysis of the inspection ...

Laser powder deposition is a process where a powder is sprayed on to a substrate at the same time as a laser is used to melt it. In this way layers of the powder material are built up into structures that can be very fine and complex. For critical requirements it is useful to inspect the structure as the layers are deposited as the final component may have considerable added value. The main challenge for the NDT methods are the small sizes involved, which in turn lead to detection of small flaws being required. Laser ultrasonics, laser thermography and eddy currents were identified as methods that might be deployed for the inspection. This paper describes the results obtained from these methods on a specially developed set of reference samples and on specific deposition samples with induced flaws.

The assurance of technical safety and quality of materials, parts and components during production and operation, along with monitoring and control of structural health processes and other scenarios, has become essential for modern high-tech industry. As a result, the market demands for NDE equipment and services are growing in respect to specific applications and fit-for-purpose equipment. Furthermore, NDT has become important for national policies directed towards the development of a national engineering infrastructure and to meet government directives. The development of industries and the use of techniques, which may cause severe damage in case of failure, are also subject to international cooperation and agreements. As a result, within the international framework, each nation has to assume responsibility for safe, secure and controlled technologies. These aspects prompted the establishment of NDE centers in countries with high-tech industry and installations, such as nuclear p...