Simulation Studies on Image Reconstruction Algorithm for Portable Electrical Capacitance Tomography

Electrical capacitance tomography (ECT) is a non-invasive and non-intrusive internal visualization tomographic modality which promising a better quantification by providing cross-sectional distribution information of any kind of multiphase flow. These studies aim to investigate the non-iterative and iterative image reconstruction for 16 channels of portable electrical capacitance tomography (ECT) through simulation work. Linear Back Projection (LBP) as a non-iterative algorithm was compared with the Landweber and generalized vector sampled pattern matching (GVSPM) iterative algorithm for four cases which are core flow, annular flow, stratified flow and two circles by evaluation of image error and image correlation. The results show Landweber algorithms produces lowest percentage error, close to phantom as higher correlation coefficient and acceptable elapsed time. Iterative image reconstruction will produce accurate results by eliminating the artifacts near actual object and enhance the capability of segmented ECT in multiphase flow identification

Data Conversion Within Energy Constrained Environments

Within scientific research, engineering, and consumer electronics, there is a multitude of new discrete sensor-interfaced devices. Maintaining high accuracy in signal quantization while staying within the strict power-budget of these devices is a very challenging problem. Traditional paths to solving this problem include researching more energy-efficient digital topologies as well as digital scaling.;This work offers an alternative path to lower-energy expenditure in the quantization stage --- content-dependent sampling of a signal. Instead of sampling at a constant rate, this work explores techniques which allow sampling based upon features of the signal itself through the use of application-dependent analog processing. This work presents an asynchronous sampling paradigm, based off the use of floating-gate-enabled analog circuitry. The basis of this work is developed through the mathematical models necessary for asynchronous sampling, as well the SPICE-compatible models necessary for simulating floating-gate enabled analog circuitry. These base techniques and circuitry are then extended to systems and applications utilizing novel analog-to-digital converter topologies capable of leveraging the non-constant sampling rates for significant sample and power savings

Lens integrated laser based optical tomography system with back-projection algorithm

This research investigates the methods of implementing switch mode parallel beam projection technique into optical tomography instrument, and observes the effects of lens in optical system tomography. In addition, the research is focused on measuring the maximum size of phantom that can be captured for concentration profile. There are two types of sources that are used in tomography system which are high and low radiation sources. In this research, low radiation source is used as a medium to measure phantom inside the pipe. There are many types of components that produce light including the light-emitting diode (LED), infrared and laser. The tests are done using laser. Pipe has 100 mm inner diameter and the convex lens is applied in front of light component to change the angle of the transmitted light. The received light is captured by the sensor for further analysis to determine phantom inside the pipe region. Result shows that the optical tomography combine with lens is easier to manage the coverage of region. The results indicate that the proposed system is suitable for object application range between 8 mm to 80 mm

Ultrasonic sensor platforms for non-destructive evaluation

Robotic vehicles are receiving increasing attention for use in Non-Destructive Evaluation (NDE), due to their attractiveness in terms of cost, safety and their accessibility to areas where manual inspection is not practical. A reconfigurable Lamb wave scanner, using autonomous robotic platforms is presented. The scanner is built from a fleet of wireless miniature robotic vehicles, each with a non-contact ultrasonic payload capable of generating the A0 Lamb wave mode in plate specimens. An embedded Kalman filter gives the robots a positional accuracy of 10mm. A computer simulator, to facilitate the design and assessment of the reconfigurable scanner, is also presented. Transducer behaviour has been simulated using a Linear Systems approximation (LS), with wave propagation in the structure modelled using the Local Interaction Simulation Approach (LISA). Integration of the LS and LISA approaches were validated for use in Lamb wave scanning by comparison with both analytical techniques and more computationally intensive commercial finite element/diference codes. Starting with fundamental dispersion data, the work goes on to describe the simulation of wave propagation and the subsequent interaction with artificial defects and plate boundaries. The computer simulator was used to evaluate several imaging techniques, including local inspection of the area under the robot and an extended method that emits an ultrasonic wave and listens for echos (B-Scan). These algorithms were implemented in the robotic platform and experimental results are presented. The Synthetic Aperture Focusing Technique (SAFT) was evaluated as a means of improving the fidelity of B-Scan data. It was found that a SAFT is only effective for transducers with reasonably wide beam divergence, necessitating small transducers with a width of approximately 5mm. Finally, an algorithm for robot localisation relative to plate sections was proposed and experimentally validated

Electronics for Sensors

The aim of this Special Issue is to explore new advanced solutions in electronic systems and interfaces to be employed in sensors, describing best practices, implementations, and applications. The selected papers in particular concern photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) interfaces and applications, techniques for monitoring radiation levels, electronics for biomedical applications, design and applications of time-to-digital converters, interfaces for image sensors, and general-purpose theory and topologies for electronic interfaces

Integrated Circuits and Systems for Smart Sensory Applications

Connected intelligent sensing reshapes our society by empowering people with increasing new ways of mutual interactions. As integration technologies keep their scaling roadmap, the horizon of sensory applications is rapidly widening, thanks to myriad light-weight low-power or, in same cases even self-powered, smart devices with high-connectivity capabilities. CMOS integrated circuits technology is the best candidate to supply the required smartness and to pioneer these emerging sensory systems. As a result, new challenges are arising around the design of these integrated circuits and systems for sensory applications in terms of low-power edge computing, power management strategies, low-range wireless communications, integration with sensing devices. In this Special Issue recent advances in application-specific integrated circuits (ASIC) and systems for smart sensory applications in the following five emerging topics: (I) dedicated short-range communications transceivers; (II) digital smart sensors, (III) implantable neural interfaces, (IV) Power Management Strategies in wireless sensor nodes and (V) neuromorphic hardware

Capacitance Based Virtual Instrument Mass Flow Measuring System

The research program conducted at the MMU into the design and development of a Virtual Instrument ECT Imaging System is a continuation from preceding investigations conducted by the MMU into tomographic imaging. The rationale behind the MMU tomographic imaging system is a response to the need for a robust and flexible proprietary tomographic imaging system appropriate for large industrial systems. The MMU Virtual Instrument ECT Imaging System consists of capacitance sensor(s), capacitance measuring hardware and the National Instruments (NI) PXI modular data acquisition system on which runs NI’s LabVIEW graphical programming environment. The MMU tomographic imaging system is capable of high tomographic speed imaging from single and dual plane sensing arrays. The purpose of this MSc project is, by utilising the MMU Virtual Instrument ECT Imaging System, to design and develop a virtual instrument measurement system for the purpose of measuring mass flow and flow velocity. Evaluation of the virtual instrument measurement system is achieved by measuring the flow of polypropylene pellets through a vertical, hopper fed, gravity-conveyed flow system fitted with two axially spaced 8 electrode transducers. Pellet mass flow is determined from the averaged volumetric concentration of pellet materials present in the capacitance sensor placed in the upstream path of the pellet flow. Pellet velocity is determined by the cross correlation of the two random noise patterns generated by the pellets as it passes through the two capacitance sensors placed in the upstream and downstream path of the pellet flow. Results are presented which show the relationship between the actual measured mass flow and the mean volumetric concentration taken from the upstream sensor compared to the number of independent normalised capacitance measurements taken from the upstream sensor. Also presented are results which relate the accuracy of the measured flow velocity to the number of independent normalised capacitance measurements taken from the upstream and downstream sensors. The results presented show that as the number of independent normalised capacitance measurements taken from both the capacitance sensors are reduced, the electrostatic field distribution within the sensors becomes more inhomogeneous which has an adverse affect v on the measurement accuracy of mass flow. Conversely, by increasing the number of independent normalised capacitance measurements taken from both the capacitance sensors has a detrimental affect on the accuracy of flow velocity measurement. The results shown prove that the MMU Virtual Instrument ECT Imaging System is capable of individual accurate measurement of either mass flow or flow velocity. But, due to the limitations encountered with the current available hardware, simultaneous and accurate measurement of mass flow and flow velocity is impractical