Vasteajan mittausjärjestelmän suunnittelu, toteutus ja testaus

A touchscreen is a commonly used medium for the interaction between a user and a device. Response to user's action is often indicated visually on the screen after a certain delay. This interface latency is inherent in any computer system. Studies indicate that the latency has a major contribution on how users perceive the interaction with the device. While modern commercial touchscreen devices manifest latencies ranging between 50 ms and 200 ms, research indicates that the user performance for tapping tasks deteriorates at considerably lower levels and users are able to discern the latency as low as 3 ms. In this Thesis we present a novel solution for Android operated mobile devices to expose factors behind the feedback latency of a tap event. We start by reviewing the main components of the Android operating system. Next we describe the internal system elements which partake in the interaction between the user's touch input event and its corresponding visual presentation on the screen of the device. Propelled by the obtained information, we implement an affordable, fully automated system that is capable of collecting both temporal and environmental data. The constructed measurement system provided revealing results. We discovered that most of the feedback latency on a mobile device is accumulated by the internal components which are involved in presenting the visual feedback to the user. We also identified two main user action patterns which impose a huge effect upon system's responsiveness. Firstly, the location of touch is reflected in the amount of feedback latency. Secondly, the interval between two consecutive touch events might cause even unexpected results. Our study demonstrated that the latency can vary a lot between different devices by ranging from no effect on one device to a five-fold difference on another device. The study concludes that, despite the feedback latency is affected by multiple factors, the latency can be measured very precisely with the system that can be built even by an average Joe.Kosketusnäyttö on yleisesti käytetty kanava käyttäjän ja laitteen välisessä vuorovaikutuksessa. Järjestelmän palaute käyttäjän antamaan syötteeseen esitetään usein visuaalisesti laitteen näytöllä. Vasteen tuottamisessa syntyy kuitenkin jonkin verran viivettä eli latenssia. Tutkimusten mukaan viiveellä on suuri vaikutus käyttäjäkokemukseen. Nykyisten kosketuslaitteiden latenssi vaihtelee yleensä 50 ja 200 millisekunnin välillä. Kosketuspohjaisten tapahtumien suorittamisen on todettu heikentyvät jo huomattavasti pienemmän viiveen johdosta ja jopa alle kolme millisekuntia kestävä viive on vielä havaittavissa. Tässä diplomityössä esitetään Android-pohjaisille mobiililaitteille luotu edullinen järjestelmä, jonka avulla pystytään mittaamaan käyttäjän näytölle luoman kosketuksen ja sitä vastaavan järjestelmän antaman visuaalisen palautteen välistä viivettä. Työssä esitetellään ensin Android-käyttöjärjestelmän komponentit, jotka osallistuvat tämän tapahtumaketjun suorittamiseksi vaadittaviin toimintoihin. Tietojen pohjalta luodaan järjestelmä, jolla voidaan kerätä automaattisesti dataa viiveen eri syntykohdista ja sen ympäristöön littyvistä seikoista. Datan avulla pystytään aiempaa paremmin arvioimaan viiveen syntyyn vaikuttavia tekijöitä. Saatua tietoa voidaan hyödyntää yleisesti viiveen hallitsemiseen tähtääviin toimenpiteisiin ja siten lopulta käyttäjäkokemuksen parantamiseen. Järjestelmällä mitatuista tuloksista selviää, että suurin osa tapahtumaketjun latenssista syntyy käyttäjälle esitettävän visuaalisen palautteen vaatimiin toimenpiteisiin. Lisäksi työ tuo esille kaksi käyttäjän syötteen antamiseen liittyvää toimintatapaa, joilla on suuri vaikutus latenssiin. Kosketuksen sijainti ruudulla ja kahden peräkkäisen kosketuksen välinen aika vaikuttavat vasteaikaan. Latenssi ei aina muodostu suoraviivaisesti ja se voi ilmentää jopa yllättäviä piirteitä eri laitteiden välillä: toimintatapa yhdessä laitteessa ei vaikuta tulokseen, mutta saattaa toisessa laitteessa näkyä moninkertaisena erona. Vaikka latenssin syntyyn vaikuttaa monta eri tekijää, sitä voidaan onneksi mitata erittäin tarkasti järjestelmällä, jonka jopa Matti Meikäläinen pystyy rakentamaan

Design of Analog Front-End of Touch-Screen Controller with Enhanced Noise Immunity and Configurable SNR and Frame Rate

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2017. 2. 정덕균.A design of analog front-end (AFE) for touch-screen controller (TSC) with highly enhanced noise immunity and configurable signal-to-noise ratio (SNR) and frame rate is proposed. First, the AFE for the mobile TSC is presented, which provides a configurable SNR and frame rate. The AFE configures its SNR and frame rate by adjusting the sampling cycles of the employed ADC. The test chip is fabricated in a 0.18-μm CMOS process and occupies a 2.2-mm2 active area. The test chip achieves 60-dB SNR and 200-Hz frame rate with 12 × 8 TSP. The SNR can be adjusted from 40 to 67 dB, while the frame rate is then inversely scaled from 50 Hz to 6.4 kHz. The test chip consumes 6.26 mW from a 3.3-V supply. The AFE for the tablet TSC is also presented, which provides highly enhanced noise immunity and configurable SNR and frame rate. The proposed AFE provides TX channels of 36 and RX channels of 64 in order to support a large-size TSP. A multi-driving TX structure with frequency-hopping signal generator is employed to improve the SNR and noise immunity. For a suppression of severe noise interference injected through the TSP, the RX sensing block adopts pre-filtering differential sensing method and high-order noise filtering structure. The AFE supports configurable SNR and frame rate with on-chip frame-rate controller. The test chip is fabri-cated in a 0.18-μm CMOS process. The active area of the test chip is 36 mm2. A 12.2-inch TSP with TX channels of 36 and RX channels of 64 is used in the measurement. The test chip achieves 54-dB SNR and 120-Hz frame rate with a finger touch. The frame rate can be adjusted from 85 to 385 Hz. The test chip achieves up to 20-Vpp noise immunity. The test chip consumes 94.5 mW with a 3.3-V supply.CHAPTER 1 INTRODUCTION 1 1.1 MOTIVATION 1 1.2 THESIS ORGANIZATION 3 CHAPTER 2 BASIC STUDY ON TOUCH-SCREEN CONTROLLER 5 2.1 TOUCH-SCREEN PANEL 5 2.2 TOUCH-SCREEN CONTROLLER 8 2.2.1 OVERVIEW ON TSC 8 2.3 ANALOG FRONT-END OF TSC 11 2.3.1 PERFORMANCE METRIC 12 2.3.2 DESIGN ISSUES OF AFE 15 CHAPTER 3 AFE OF MOBILE TSC WITH CONFIGURABLE SNR AND FRAME RATE 18 3.1 OVERVIEW 18 3.2 SYSTEM ARCHITECTURE 21 3.3 CONFIGURABLE SNR AND FRAME RATE 23 3.4 MEASUREMENT RESULTS 29 CHAPTER 4 AFE OF TABLET TSC WITH ENHANCED NOISE IMMUNITY 35 4.1 OVERVIEW 35 4.2 DESIGN ISSUES BY LARGE-SIZE TSP 38 4.3 DESIGN ISSUES BY NOISE INTERFERENCE 40 4.3.1 NOISE INTERFERENCE 40 4.3.2 DISPLAY NOISE REJECTION TECHNIQUE 43 4.3.3 CHARGER NOISE FILTERING TECHNIQUE 46 4.3.4 HIGH-VOLTAGE TX TECHNIQUE 50 4.3.5 MULTI-DRIVING TX TECHNIQUE 52 4.4 PROPOSED ARCHITECTURE 66 4.4.1 TX DRIVING ARCHITECTURE 67 4.4.2 RX SENSING ARCHITECTURE 71 4.5 MULTI-DRIVING TX STRUCTURE 75 4.5.1 CONSIDERATIONS FOR TX MODULATION SEQUENCE 75 4.5.2 COMPARISON OF MODULATION SEQUENCES 76 4.5.3 MODIFIED BUSH-TYPE HADAMARD MATRIX 79 4.6 NOISE FILTERING RX 83 4.6.1 PRE-FILTERING DIFFERENTIAL SENSING METHOD 83 4.6.2 NOISE-IMMUNE SENSING STRUCTURE 87 4.6.3 CONFIGURABLE SNR AND FRAME RATE 106 4.6.4 RX MODULATION 112 4.7 CIRCUIT IMPLEMENTATION 120 4.7.1 CHARGE AMPLIFIER AND BAND-PASS FILTER 121 4.7.2 CAPACITIVE DIFFERENTIAL AMPLIFIER 123 4.7.3 MIXER AND RX MODULATION 125 4.7.4 LOW-PASS FILTER 127 4.7.5 INCREMENTAL ΔΣ ADC 128 4.7.6 DIGITAL DEMODULATION 130 4.7.7 TX DRIVING BLOCK 131 4.8 MEASUREMENT RESULTS 132 4.8.1 TOUCH-SCREEN PANEL (TSP) 132 4.8.2 MEASUREMENT ENVIRONMENTS 133 4.8.3 FABRICATED AFE 134 4.8.4 OPERATION OF THE FABRICATED AFE 135 4.8.5 SNR MEASUREMENT 139 4.8.6 CONFIGURABLE SNR AND FRAME RATE 139 4.8.7 NOISE IMMUNITY 141 4.8.8 COMPARISON WITH OTHER WORKS 157 CHAPTER 5 CONCLUSION 158 BIBLIOGRAPHY 160 초 록 170Docto

Physical sketching tools and techniques for customized sensate surfaces

Sensate surfaces are a promising avenue for enhancing human interaction with digital systems due to their inherent intuitiveness and natural user interface. Recent technological advancements have enabled sensate surfaces to surpass the constraints of conventional touchscreens by integrating them into everyday objects, creating interactive interfaces that can detect various inputs such as touch, pressure, and gestures. This allows for more natural and intuitive control of digital systems. However, prototyping interactive surfaces that are customized to users' requirements using conventional techniques remains technically challenging due to limitations in accommodating complex geometric shapes and varying sizes. Furthermore, it is crucial to consider the context in which customized surfaces are utilized, as relocating them to fabrication labs may lead to the loss of their original design context. Additionally, prototyping high-resolution sensate surfaces presents challenges due to the complex signal processing requirements involved. This thesis investigates the design and fabrication of customized sensate surfaces that meet the diverse requirements of different users and contexts. The research aims to develop novel tools and techniques that overcome the technical limitations of current methods and enable the creation of sensate surfaces that enhance human interaction with digital systems.Sensorische Oberflächen sind aufgrund ihrer inhärenten Intuitivität und natürlichen Benutzeroberfläche ein vielversprechender Ansatz, um die menschliche Interaktionmit digitalen Systemen zu verbessern. Die jüngsten technologischen Fortschritte haben es ermöglicht, dass sensorische Oberflächen die Beschränkungen herkömmlicher Touchscreens überwinden, indem sie in Alltagsgegenstände integriert werden und interaktive Schnittstellen schaffen, die diverse Eingaben wie Berührung, Druck, oder Gesten erkennen können. Dies ermöglicht eine natürlichere und intuitivere Steuerung von digitalen Systemen. Das Prototyping interaktiver Oberflächen, die mit herkömmlichen Techniken an die Bedürfnisse der Nutzer angepasst werden, bleibt jedoch eine technische Herausforderung, da komplexe geometrische Formen und variierende Größen nur begrenzt berücksichtigt werden können. Darüber hinaus ist es von entscheidender Bedeutung, den Kontext, in dem diese individuell angepassten Oberflächen verwendet werden, zu berücksichtigen, da eine Verlagerung in Fabrikations-Laboratorien zum Verlust ihres ursprünglichen Designkontextes führen kann. Zudem stellt das Prototyping hochauflösender sensorischer Oberflächen aufgrund der komplexen Anforderungen an die Signalverarbeitung eine Herausforderung dar. Diese Arbeit erforscht dasDesign und die Fabrikation individuell angepasster sensorischer Oberflächen, die den diversen Anforderungen unterschiedlicher Nutzer und Kontexte gerecht werden. Die Forschung zielt darauf ab, neuartigeWerkzeuge und Techniken zu entwickeln, die die technischen Beschränkungen derzeitigerMethoden überwinden und die Erstellung von sensorischen Oberflächen ermöglichen, die die menschliche Interaktion mit digitalen Systemen verbessern

New generation of interactive platforms based on novel printed smart materials

Programa doutoral em Engenharia Eletrónica e de Computadores (área de Instrumentação e Microssistemas Eletrónicos)The last decade was marked by the computer-paradigm changing with other digital devices suddenly becoming available to the general public, such as tablets and smartphones. A shift in perspective from computer to materials as the centerpiece of digital interaction is leading to a diversification of interaction contexts, objects and applications, recurring to intuitive commands and dynamic content that can proportionate more interesting and satisfying experiences. In parallel, polymer-based sensors and actuators, and their integration in different substrates or devices is an area of increasing scientific and technological interest, which current state of the art starts to permit the use of smart sensors and actuators embodied within the objects seamlessly. Electronics is no longer a rigid board with plenty of chips. New technological advances and perspectives now turned into printed electronics in polymers, textiles or paper. We are assisting to the actual scaling down of computational power into everyday use objects, a fusion of the computer with the material. Interactivity is being transposed to objects erstwhile inanimate. In this work, strain and deformation sensors and actuators were developed recurring to functional polymer composites with metallic and carbonaceous nanoparticles (NPs) inks, leading to capacitive, piezoresistive and piezoelectric effects, envisioning the creation of tangible user interfaces (TUIs). Based on smart polymer substrates such as polyvinylidene fluoride (PVDF) or polyethylene terephthalate (PET), among others, prototypes were prepared using piezoelectric and dielectric technologies. Piezoresistive prototypes were prepared with resistive inks and restive functional polymers. Materials were printed by screen printing, inkjet printing and doctor blade coating. Finally, a case study of the integration of the different materials and technologies developed is presented in a book-form factor.A última década foi marcada por uma alteração do paradigma de computador pelo súbito aparecimento dos tablets e smartphones para o público geral. A alteração de perspetiva do computador para os materiais como parte central de interação digital levou a uma diversificação dos contextos de interação, objetos e aplicações, recorrendo a comandos intuitivos e conteúdos dinâmicos capazes de tornarem a experiência mais interessante e satisfatória. Em simultâneo, sensores e atuadores de base polimérica, e a sua integração em diferentes substratos ou dispositivos é uma área de crescente interesse científico e tecnológico, e o atual estado da arte começa a permitir o uso de sensores e atuadores inteligentes perfeitamente integrados nos objetos. Eletrónica já não é sinónimo de placas rígidas cheias de componentes. Novas perspetivas e avanços tecnológicos transformaram-se em eletrónica impressa em polímeros, têxteis ou papel. Neste momento estamos a assistir à redução da computação a objetos do dia a dia, uma fusão do computador com a matéria. A interatividade está a ser transposta para objetos outrora inanimados. Neste trabalho foram desenvolvidos atuadores e sensores e de pressão e de deformação com recurso a compostos poliméricos funcionais com tintas com nanopartículas (NPs) metálicas ou de base carbónica, recorrendo aos efeitos capacitivo, piezoresistivo e piezoelétrico, com vista à criação de interfaces de usuário tangíveis (TUIs). Usando substratos poliméricos inteligentes tais como fluoreto de polivinilideno (PVDF) ou politereftalato de etileno (PET), entre outos, foi possível a preparação de protótipos de tecnologia piezoelétrica ou dielétrica. Os protótipos de tecnologia piezoresistiva foram feitos com tintas resistivas e polímeros funcionais resistivos. Os materiais foram impressos por serigrafia, jato de tinta, impressão por aerossol e revestimento de lâmina doctor blade. Para terminar, é apresentado um caso de estudo da integração dos diferentes materiais e tecnologias desenvolvidos sob o formato de um livro.This project was supported by FCT – Fundação para a Ciência e a Tecnologia, within the doctorate grant with reference SFRH/BD/110622/2015, by POCH – Programa Operacional Capital Humano, and by EU – European Union

An Event-Triggered Low-Cost Tactile Perception System for Social Robot's Whole Body Interaction

The social interaction is one of the necessary skills for social robots to better integrate into human society. However, current social robots interact mainly through audio and visual means with little reliance on haptic interaction. There still exist many obstacles for social robots to interact through touch: 1) the complex manufacturing process of the tactile sensor array is the main obstacle to lowering the cost of production; 2) the haptic interaction mode is complex and diverse. There are no social robot interaction standards and data sets for tactile interactive behavior in the public domain. In view of this, our research looks into the following aspects of tactile perception system: 1) Development of low-cost tactile sensor array, including sensor principle, simulation, manufacture, front-end electronics, examination, then applied to the social robot's whole body; 2) Establishment of the tactile interactive model and an event-triggered perception model in a social interactive application for the social robot, then design preprocessing and classification algorithm. In this research, we use k-nearest neighbors, tree, support vector machine and other classification algorithms to classify touch behaviors into six different classes. In particular, the cosine k-nearest neighbors and quadratic support vector machine achieve an overall mean accuracy rate of more than 68%, with an individual accuracy rate of more than 80%. In short, our research provides new directions in achieving low-cost intelligent touch interaction for social robots in a real environment. The low-cost tactile sensor array solution and interactive models are expected to be applied to social robots on a large scale

Design and characterization of the measurement electronics for a magnetic induction tomography imaging system

Includes abstract.Includes bibliographical references (p. 103-110).A data acquisition transceiver circuit for magnetic induction tomography (MIT) has been developed. MIT is a type of tomography technique that is sensitive to the conductivity of objects, and which can be used in both industrial and biomedical applications. A detailed design process of the MIT transceiver board and the coupling sensor coils are presented in this dissertation. For the purpose of testing the designed hardware, a three channel MIT measuring system was assembled, and various experiments were run on the system. Several different samples with high conductivity (metal sheets) or low conductivity (saline solution) were used to test the performance of the designed transceiver. Its suitability for being applied to the actual MIT system could then be assessed. The noise characteristics and stability of the system were also characterised. A complete eight channel MIT measurement system is presently being assembled based on the prototypes presented in the dissertation. The results obtained from the experiments are very promising. The construction of the multi-channel MIT system and the image reconstruction can confidently be expected in future development

Machine Learning in Sensors and Imaging

Machine learning is extending its applications in various fields, such as image processing, the Internet of Things, user interface, big data, manufacturing, management, etc. As data are required to build machine learning networks, sensors are one of the most important technologies. In addition, machine learning networks can contribute to the improvement in sensor performance and the creation of new sensor applications. This Special Issue addresses all types of machine learning applications related to sensors and imaging. It covers computer vision-based control, activity recognition, fuzzy label classification, failure classification, motor temperature estimation, the camera calibration of intelligent vehicles, error detection, color prior model, compressive sensing, wildfire risk assessment, shelf auditing, forest-growing stem volume estimation, road management, image denoising, and touchscreens

Sensitive and Makeable Computational Materials for the Creation of Smart Everyday Objects

The vision of computational materials is to create smart everyday objects using the materi- als that have sensing and computational capabilities embedded into them. However, today’s development of computational materials is limited because its interfaces (i.e. sensors) are unable to support wide ranges of human interactions , and withstand the fabrication meth- ods of everyday objects (e.g. cutting and assembling). These barriers hinder citizens from creating smart every day objects using computational materials on a large scale. To overcome the barriers, this dissertation presents the approaches to develop compu- tational materials to be 1) sensitive to a wide variety of user interactions, including explicit interactions (e.g. user inputs) and implicit interactions (e.g. user contexts), and 2) makeable against a wide range of fabrication operations, such cutting and assembling. I exemplify the approaches through five research projects on two common materials, textile and wood. For each project, I explore how a material interface can be made to sense user inputs or activities, and how it can be optimized to balance sensitivity and fabrication complexity. I discuss the sensing algorithms and machine learning model to interpret the sensor data as high-level abstraction and interaction. I show the practical applications of developed computational materials. I demonstrate the evaluation study to validate their performance and robustness. In the end of this dissertation, I summarize the contributions of my thesis and discuss future directions for the vision of computational materials