Display system employing acousto-optic tunable filter

An acousto-optic tunable filter (AOTF) is employed to generate a display by driving the AOTF with a RF electrical signal comprising modulated red, green, and blue video scan line signals and scanning the AOTF with a linearly polarized, pulsed light beam, resulting in encoding of color video columns (scan lines) of an input video image into vertical columns of the AOTF output beam. The AOTF is illuminated periodically as each acoustically-encoded scan line fills the cell aperture of the AOTF. A polarizing beam splitter removes the unused first order beam component of the AOTF output and, if desired, overlays a real world scene on the output plane. Resolutions as high as 30,000 lines are possible, providing holographic display capability

Display system employing acousto-optic tunable filter

An acousto-optic tunable filter (AOTF) is employed to generate a display by driving the AOTF with a RF electrical signal comprising modulated red, green, and blue video scan line signals and scanning the AOTF with a linearly polarized, pulsed light beam, resulting in encoding of color video columns (scan lines) of an input video image into vertical columns of the AOTF output beam. The AOTF is illuminated periodically as each acoustically-encoded scan line fills the cell aperture of the AOTF. A polarizing beam splitter removes the unused first order beam component of the AOTF output and, if desired, overlays a real world scene on the output plane. Resolutions as high as 30,000 lines are possible, providing holographic display capability

Smart Gas Sensors: Materials, Technologies, Practical ‎Applications, and Use of Machine Learning – A Review

The electronic nose, popularly known as the E-nose, that combines gas sensor arrays (GSAs) with machine learning has gained a strong foothold in gas sensing technology. The E-nose designed to mimic the human olfactory system, is used for the detection and identification of various volatile compounds. The GSAs develop a unique signal fingerprint for each volatile compound to enable pattern recognition using machine learning algorithms. The inexpensive, portable and non-invasive characteristics of the E-nose system have rendered it indispensable within the gas-sensing arena. As a result, E-noses have been widely employed in several applications in the areas of the food industry, health management, disease diagnosis, water and air quality control, and toxic gas leakage detection. This paper reviews the various sensor fabrication technologies of GSAs and highlights the main operational framework of the E-nose system. The paper details vital signal pre-processing techniques of feature extraction, feature selection, in addition to machine learning algorithms such as SVM, kNN, ANN, and Random Forests for determining the type of gas and estimating its concentration in a competitive environment. The paper further explores the potential applications of E-noses for diagnosing diseases, monitoring air quality, assessing the quality of food samples and estimating concentrations of volatile organic compounds (VOCs) in air and in food samples. The review concludes with some challenges faced by E-nose, alternative ways to tackle them and proposes some recommendations as potential future work for further development and design enhancement of E-noses

An Optical Density Detection Platform with Integrated Microfluidics for In Situ Growth, Monitoring, and Treatment of Bacterial Biofilms

Systems engineering strategies utilizing platform-based design methodologies are implemented to achieve the integration of biological and physical system components in a biomedical system. An application of this platform explored, in which an integrated microsystem is developed capable of the on-chip growth, monitoring, and treatment of bacterial biofilms for drug development and fundamental study applications. In this work, the developed systems engineering paradigm is utilized to develop a device system implementing linear array charge-coupled devices to enable real time, non-invasive, label-free monitoring of bacterial biofilms. A novel biofilm treatment method is demonstrated within the developed microsystem showing drastic increases in treatment efficacy by decreasing both bacterial biomass and cell viability within treated biofilms. Demonstration of this treatment at the microscale enables future applications of this method for the in vivo treatment of biofilm-associated infections

A Review on Key Issues and Challenges in Devices Level MEMS Testing

The present review provides information relevant to issues and challenges in MEMS testing techniques that are implemented to analyze the microelectromechanical systems (MEMS) behavior for specific application and operating conditions. MEMS devices are more complex and extremely diverse due to the immersion of multidomains. Their failure modes are distinctive under different circumstances. Therefore, testing of these systems at device level as well as at mass production level, that is, parallel testing, is becoming very challenging as compared to the IC test, because MEMS respond to electrical, physical, chemical, and optical stimuli. Currently, test systems developed for MEMS devices have to be customized due to their nondeterministic behavior and complexity. The accurate measurement of test systems for MEMS is difficult to quantify in the production phase. The complexity of the device to be tested required maturity in the test technique which increases the cost of test development; this practice is directly imposed on the device cost. This factor causes a delay in time-to-market

A Review on Key Issues and Challenges in Devices Level MEMS Testing

The present review provides information relevant to issues and challenges in MEMS testing techniques that are implemented to analyze the microelectromechanical systems (MEMS) behavior for specific application and operating conditions. MEMS devices are more complex and extremely diverse due to the immersion of multidomains. Their failure modes are distinctive under different circumstances. Therefore, testing of these systems at device level as well as at mass production level, that is, parallel testing, is becoming very challenging as compared to the IC test, because MEMS respond to electrical, physical, chemical, and optical stimuli. Currently, test systems developed for MEMS devices have to be customized due to their nondeterministic behavior and complexity. The accurate measurement of test systems for MEMS is difficult to quantify in the production phase. The complexity of the device to be tested required maturity in the test technique which increases the cost of test development; this practice is directly imposed on the device cost. This factor causes a delay in time-to-market

Solid State Circuits Technologies

The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book

Fabrication of SOI micromechanical devices

This work reports on studies and the fabrication process development of micromechanical silicon-on-insulator (SOI) devices. SOI is a promising starting material for fabrication of single crystal silicon micromechanical devices and basis for monolithic integration of sensors and integrated circuits. The buried oxide layer of an SOI wafer offers an excellent etch stop layer for silicon etching and sacrificial layer for fabrication of capacitive sensors. Deep silicon etching is studied and the aspect ratio dependency of the etch rate and loading effects are described and modeled. The etch rate of the deep silicon etching process is modeled with a simple flow conductance model, which takes into account only the initial etch rate and reaction probability and flow resistance of the etched feature. The used model predicts qualitatively the aspect-ratio-dependent etch rate for varying trench widths and rectangular shapes. The design related loading can be modeled and the effects of the loading can be minimized with proper etch mask design. The basic SOI micromechanics process is described and the drawbacks and limitations of the process are discussed. Improvements to the process are introduced as well as IR microscopy as a new method to inspect the sacrificial etch length of the SOI structure. A new fabrication process for SOI micromechanics has been developed that alleviates metallization problems during the wet etching of the sacrificial layer. The process is based on forming closed cavities under the structure layer of SOI with the help of a semi-permeable polysilicon film. Prototype SOI device fabrication results are presented. High Q single crystal silicon micro resonators have potential for replacing bulky quartz resonators in clock circuits. Monolithic integration of micromechanical devices and an integrated circuit has been demonstrated with the developed process using the embedded vacuum cavities.reviewe

Hydrogel-based logic circuits for planar microfluidics and lab-on-a-chip automation

The transport of vital nutrient supply in fluids as well as the exchange of specific chemical signals from cell to cell has been optimized over billion years of natural evolution. This model from nature is a driving factor in the field of microfluidics, which investigates the manipulation of the smallest amounts of fluid with the aim of applying these effects in fluidic microsystems for technical solutions. Currently, microfluidic systems are receiving attention, especially in diagnostics, \textit{e.g.} as SARS-CoV-2 antigen tests, or in the field of high-throughput analysis, \textit{e.g.} for cancer research. Either simple-to-use or large-scale integrated microfluidic systems that perform biological and chemical laboratory investigations on a so called Lab-on-a-Chip (LoC) provide fast analysis, high functionality, outstanding reproducibility at low cost per sample, and small demand of reagents due to system miniaturization. Despite the great progress of different LoC technology platforms in the last 30 years, there is still a lack of standardized microfluidic components, as well as a high-performance, fully integrated on-chip automation. Quite promising for the microfluidic system design is the similarity of the Kirchhoff's laws from electronics to predict pressure and flow rate in microchannel structures. One specific LoC platform technology approach controls fluids by active polymers which respond to specific physical and chemical signals in the fluid. Analogue to (micro-)electronics, these active polymer materials can be realized by various photolithographic and micro patterning methods to generate functional elements at high scalability. The so called chemofluidic circuits have a high-functional potential and provide “real” on-chip automation, but are complex in system design. In this work, an advanced circuit concept for the planar microfluidic chip architecture, originating from the early era of the semiconductor-based resistor-transistor-logic (RTL) will be presented. Beginning with the state of the art of microfluidic technologies, materials, and methods of this work will be further described. Then the preferred fabrication technology is evaluated and various microfluidic components are discussed in function and design. The most important component to be characterized is the hydrogel-based chemical volume phase transition transistor (CVPT) which is the key to approach microfluidic logic gate operations. This circuit concept (CVPT-RTL) is robust and simple in design, feasible with common materials and manufacturing techniques. Finally, application scenarios for the CVPT-RTL concept are presented and further development recommendations are proposed.:1 The transistor: invention of the 20th century 2 Introduction to fluidic microsystems and the theoretical basics 2.1 Fluidic systems at the microscale 2.2 Overview of microfluidic chip fabrication 2.2.1 Common substrate materials for fluidic microsystems 2.2.2 Structuring polymer substrates for microfluidics 2.2.3 Polymer chip bonding technologies 2.3 Fundamentals and microfluidic transport processes 2.3.1 Fluid dynamics in miniaturized systems 2.3.2 Hagen-Poiseuille law: the fluidic resistance 2.3.3 Electronic and microfluidic circuit model analogy 2.3.4 Limits of the electro-fluidic analogy 2.4 Active components for microfluidic control 2.4.1 Fluid transport by integrated micropumps 2.4.2 Controlling fluids by on-chip microvalves 2.4.3 Hydrogel-based microvalve archetypes 2.5 LoC technologies: lost in translation? 2.6 Microfluidic platforms providing logic operations 2.6.1 Hybrids: MEMS-based logic concepts 2.6.2 Intrinsic logic operators for microfluidic circuits 2.7 Research objective: microfluidic hydrogel-based logic circuits 3 Stimuli-responsive polymers for microfluidics 3.1 Introduction to hydrogels 3.1.1 Application variety of hydrogels 3.1.2 Hydrogel microstructuring methods 3.2 Theory: stimuli-responsive hydrogels 3.3 PNIPAAm: a multi-responsive hydrogel 4 Design, production and characterization methods of hydrogel-based microfluidic systems 4.1 The semi-automated computer aided design approach for microfluidic systems 4.2 The applied design process 4.3 Fabrication of microfluidic chips 4.3.1 Photoresist master fabrication 4.3.2 Soft lithography for PDMS chip production 4.3.3 Assembling PDMS chips by plasma bonding 4.4 Integration of functional hydrogels in microfluidic chips 4.4.1 Preparation of a monomer solution for hydrogel synthesis 4.4.2 Integration methods 4.5 Effects on hydrogel photopolymerization and the role of integration method 4.5.1 Photopolymerization from monomer solutions: managing the diffusion of free radicals 4.5.2 Hydrogel adhesion and UV light intensity distribution in the polymerization chamber 4.5.3 Hydrogel shrinkage behavior of different adhesion types 4.6 Comparison of the integration methods 4.7 Characterization setups for hydrogel actuators and microfluidic measurements . 71 4.7.1 Optical characterization method to describe swelling behavior 4.7.2 Setup of a microfluidic test stand 4.8 Conclusion: design, production and characterization methods 5 VLSI technology for hydrogel-based microfluidics 5.1 Overview of photolithography methods 5.2 Standard UV photolithography system for microfluidic structures 5.3 Self-made UV lithography system suitable for the mVLSI 5.3.1 Lithography setup for the DFR and SU-8 master exposure 5.3.2 Comparison of mask-based UV induced crosslinking for DFR and SU-8 5.4 Mask-based UV photopolymerization for mVLSI hydrogel patterning 5.4.1 Lithography setup for the photopolymerization of hydrogels 5.4.2 Hydrogel photopolymerization: experiments and results 5.4.3 Troubleshooting: photopolymerization of hydrogels 5.5 Conclusion: mVLSI technologies for hydrogel-based LoCs 6 Components for chemofluidic circuit design 6.1 Passive components in microfluidics 6.1.1 Microfluidic resistor 6.1.2 Planar-passive microfluidic signal mixer 6.1.3 Phase separation: laminar flow signal splitter 6.1.4 Hydrogel-based microfluidic one-directional valves 6.2 Hydrogel-based active components 6.2.1 Reversible hydrogel-based valves 6.2.2 Hydrogel-based variable resistors 6.2.3 CVPT: the microfluidic transistor 6.3 Conclusion: components for chemofluidic circuits 7 Hydrogel-based logic circuits in planar microfluidics 7.1 Development of a planar CVPT logic concept 7.1.1 Challenges of planar microfluidics 7.1.2 Preparatory work and conceptional basis 7.2 The microfluidic CVPT-RTL concept 7.3 The CVPT-RTL NAND gate 7.3.1 Circuit optimization stabilizing the NAND operating mode 7.3.2 Role of laminar flow for the CVPT-RTL concept 7.3.3 Hydrogel-based components for improved switching reliability 7.4 One design fits all: the NOR, AND and OR gate 7.5 Control measures for cascaded systems 7.6 Application scenarios for the CVPT-RTL concept 7.6.1 Use case: automated cell growth system 7.6.2 Use case: chemofluidic converter 7.7 Conclusion: Hydrogel-based logic circuits 8 Summary and outlook 8.1 Scientific achievements 8.2 Summarized recommendations from this work Supplementary information SI.1 Swelling degree of BIS-pNIPAAm gels SI.2 Simulated ray tracing of UV lithography setup by WinLens® SI.3 Determination of the resolution using the intercept theorem SI.4 Microfluidic master mold test structures SI.4.1 Polymer and glass mask comparison SI.4.2 Resolution Siemens star in DFR SI.4.3 Resolution Siemens star in SU-8 SI.4.4 Integration test array 300 μm for DFR and SU-8 SI.4.5 Integration test array 100 μm for SU-8 SI.4.6 Microfluidic structure for different technology parameters SI.5 Microfluidic test setups SI.6 Supplementary information: microfluidic components SI.6.1 Compensation methods for flow stabilization in microfluidic chips SI.6.2 Planar-passive microfluidic signal mixer SI.6.3 Laminar flow signal splitter SI.6.4 Variable fluidic resistors: flow rate characteristics SI.6.5 CVPT flow rate characteristics for high Rout Standard operation proceduresDer Transport von lebenswichtigen Nährstoffen in Flüssigkeiten sowie der Austausch spezifischer chemischer Signale von Zelle zu Zelle wurde in Milliarden Jahren natürlicher Evolution optimiert. Dieses Vorbild aus der Natur ist ein treibender Faktor im Fachgebiet der Mikrofluidik, welches die Manipulation kleinster Flüssigkeitsmengen erforscht um diese Effekte in fluidischen Mikrosystemen für technische Lösungen zu nutzen. Derzeit finden mikrofluidische Systeme vor allem in der Diagnostik, z.B. wie SARS-CoV-2-Antigentests, oder im Bereich der Hochdurchsatzanalyse, z.B. in der Krebsforschung, besondere Beachtung. Entweder einfach zu bedienende oder hochintegrierte mikrofluidische Systeme, die biologische und chemische Laboruntersuchungen auf einem sogenannten Lab-on-a-Chip (LoC) durchführen, bieten schnelle Analysen, hohe Funktionalität, hervorragende Reproduzierbarkeit bei niedrigen Kosten pro Probe und einen geringen Bedarf an Reagenzien durch die Miniaturisierung des Systems. Trotz des großen Fortschritts verschiedener LoC-Technologieplattformen in den letzten 30 Jahren mangelt es noch an standardisierten mikrofluidischen Komponenten sowie an einer leistungsstarken, vollintegrierten On-Chip-Automatisierung. Vielversprechend für das Design mikrofluidischer Systeme ist die Ähnlichkeit der Kirchhoff'schen Gesetze aus der Elektronik zur Vorhersage von Druck und Flussrate in Mikrokanalstrukturen. Ein spezifischer Ansatz der LoC-Plattformtechnologie steuert Flüssigkeiten durch aktive Polymere, die auf spezifische physikalische und chemische Signale in der Flüssigkeit reagieren. Analog zur (Mikro-)Elektronik können diese aktiven Polymermaterialien durch verschiedene fotolithografische und mikrostrukturelle Methoden realisiert werden, um funktionelle Elemente mit hoher Skalierbarkeit zu erzeugen.\\ Die sogenannten chemofluidischen Schaltungen haben ein hohes funktionales Potenzial und ermöglichen eine 'wirkliche' on-chip Automatisierung, sind jedoch komplex im Systemdesign. In dieser Arbeit wird ein fortgeschrittenes Schaltungskonzept für eine planare mikrofluidische Chiparchitektur vorgestellt, das aus der frühen Ära der halbleiterbasierten Resistor-Transistor-Logik (RTL) hervorgeht. Beginnend mit dem Stand der Technik der mikrofluidischen Technologien, werden Materialien und Methoden dieser Arbeit näher beschrieben. Daraufhin wird die bevorzugte Herstellungstechnologie bewertet und verschiedene mikrofluidische Komponenten werden in Funktion und Design diskutiert. Die wichtigste Komponente, die es zu charakterisieren gilt, ist der auf Hydrogel basierende chemische Volumen-Phasenübergangstransistor (CVPT), der den Schlüssel zur Realisierung mikrofluidische Logikgatteroperationen darstellt. Dieses Schaltungskonzept (CVPT-RTL) ist robust und einfach im Design und kann mit gängigen Materialien und Fertigungstechniken realisiert werden. Zuletzt werden Anwendungsszenarien für das CVPT-RTL-Konzept vorgestellt und Empfehlungen für die fortlaufende Entwicklung angestellt.:1 The transistor: invention of the 20th century 2 Introduction to fluidic microsystems and the theoretical basics 2.1 Fluidic systems at the microscale 2.2 Overview of microfluidic chip fabrication 2.2.1 Common substrate materials for fluidic microsystems 2.2.2 Structuring polymer substrates for microfluidics 2.2.3 Polymer chip bonding technologies 2.3 Fundamentals and microfluidic transport processes 2.3.1 Fluid dynamics in miniaturized systems 2.3.2 Hagen-Poiseuille law: the fluidic resistance 2.3.3 Electronic and microfluidic circuit model analogy 2.3.4 Limits of the electro-fluidic analogy 2.4 Active components for microfluidic control 2.4.1 Fluid transport by integrated micropumps 2.4.2 Controlling fluids by on-chip microvalves 2.4.3 Hydrogel-based microvalve archetypes 2.5 LoC technologies: lost in translation? 2.6 Microfluidic platforms providing logic operations 2.6.1 Hybrids: MEMS-based logic concepts 2.6.2 Intrinsic logic operators for microfluidic circuits 2.7 Research objective: microfluidic hydrogel-based logic circuits 3 Stimuli-responsive polymers for microfluidics 3.1 Introduction to hydrogels 3.1.1 Application variety of hydrogels 3.1.2 Hydrogel microstructuring methods 3.2 Theory: stimuli-responsive hydrogels 3.3 PNIPAAm: a multi-responsive hydrogel 4 Design, production and characterization methods of hydrogel-based microfluidic systems 4.1 The semi-automated computer aided design approach for microfluidic systems 4.2 The applied design process 4.3 Fabrication of microfluidic chips 4.3.1 Photoresist master fabrication 4.3.2 Soft lithography for PDMS chip production 4.3.3 Assembling PDMS chips by plasma bonding 4.4 Integration of functional hydrogels in microfluidic chips 4.4.1 Preparation of a monomer solution for hydrogel synthesis 4.4.2 Integration methods 4.5 Effects on hydrogel photopolymerization and the role of integration method 4.5.1 Photopolymerization from monomer solutions: managing the diffusion of free radicals 4.5.2 Hydrogel adhesion and UV light intensity distribution in the polymerization chamber 4.5.3 Hydrogel shrinkage behavior of different adhesion types 4.6 Comparison of the integration methods 4.7 Characterization setups for hydrogel actuators and microfluidic measurements . 71 4.7.1 Optical characterization method to describe swelling behavior 4.7.2 Setup of a microfluidic test stand 4.8 Conclusion: design, production and characterization methods 5 VLSI technology for hydrogel-based microfluidics 5.1 Overview of photolithography methods 5.2 Standard UV photolithography system for microfluidic structures 5.3 Self-made UV lithography system suitable for the mVLSI 5.3.1 Lithography setup for the DFR and SU-8 master exposure 5.3.2 Comparison of mask-based UV induced crosslinking for DFR and SU-8 5.4 Mask-based UV photopolymerization for mVLSI hydrogel patterning 5.4.1 Lithography setup for the photopolymerization of hydrogels 5.4.2 Hydrogel photopolymerization: experiments and results 5.4.3 Troubleshooting: photopolymerization of hydrogels 5.5 Conclusion: mVLSI technologies for hydrogel-based LoCs 6 Components for chemofluidic circuit design 6.1 Passive components in microfluidics 6.1.1 Microfluidic resistor 6.1.2 Planar-passive microfluidic signal mixer 6.1.3 Phase separation: laminar flow signal splitter 6.1.4 Hydrogel-based microfluidic one-directional valves 6.2 Hydrogel-based active components 6.2.1 Reversible hydrogel-based valves 6.2.2 Hydrogel-based variable resistors 6.2.3 CVPT: the microfluidic transistor 6.3 Conclusion: components for chemofluidic circuits 7 Hydrogel-based logic circuits in planar microfluidics 7.1 Development of a planar CVPT logic concept 7.1.1 Challenges of planar microfluidics 7.1.2 Preparatory work and conceptional basis 7.2 The microfluidic CVPT-RTL concept 7.3 The CVPT-RTL NAND gate 7.3.1 Circuit optimization stabilizing the NAND operating mode 7.3.2 Role of laminar flow for the CVPT-RTL concept 7.3.3 Hydrogel-based components for improved switching reliability 7.4 One design fits all: the NOR, AND and OR gate 7.5 Control measures for cascaded systems 7.6 Application scenarios for the CVPT-RTL concept 7.6.1 Use case: automated cell growth system 7.6.2 Use case: chemofluidic converter 7.7 Conclusion: Hydrogel-based logic circuits 8 Summary and outlook 8.1 Scientific achievements 8.2 Summarized recommendations from this work Supplementary information SI.1 Swelling degree of BIS-pNIPAAm gels SI.2 Simulated ray tracing of UV lithography setup by WinLens® SI.3 Determination of the resolution using the intercept theorem SI.4 Microfluidic master mold test structures SI.4.1 Polymer and glass mask comparison SI.4.2 Resolution Siemens star in DFR SI.4.3 Resolution Siemens star in SU-8 SI.4.4 Integration test array 300 μm for DFR and SU-8 SI.4.5 Integration test array 100 μm for SU-8 SI.4.6 Microfluidic structure for different technology parameters SI.5 Microfluidic test setups SI.6 Supplementary information: microfluidic components SI.6.1 Compensation methods for flow stabilization in microfluidic chips SI.6.2 Planar-passive microfluidic signal mixer SI.6.3 Laminar flow signal splitter SI.6.4 Variable fluidic resistors: flow rate characteristics SI.6.5 CVPT flow rate characteristics for high Rout Standard operation procedure

Advanced photonic and electronic systems - WILGA 2017

WILGA annual symposium on advanced photonic and electronic systems has been organized by young scientist for young scientists since two decades. It traditionally gathers more than 350 young researchers and their tutors. Ph.D students and graduates present their recent achievements during well attended oral sessions. Wilga is a very good digest of Ph.D. works carried out at technical universities in electronics and photonics, as well as information sciences throughout Poland and some neighboring countries. Publishing patronage over Wilga keep Elektronika technical journal by SEP, IJET by PAN and Proceedings of SPIE. The latter world editorial series publishes annually more than 200 papers from Wilga. Wilga 2017 was the XL edition of this meeting. The following topical tracks were distinguished: photonics, electronics, information technologies and system research. The article is a digest of some chosen works presented during Wilga 2017 symposium. WILGA 2017 works were published in Proc. SPIE vol.10445