Vision-Based Finger Detection, Tracking, and Event Identification Techniques for Multi-Touch Sensing and Display Systems

This study presents efficient vision-based finger detection, tracking, and event identification techniques and a low-cost hardware framework for multi-touch sensing and display applications. The proposed approach uses a fast bright-blob segmentation process based on automatic multilevel histogram thresholding to extract the pixels of touch blobs obtained from scattered infrared lights captured by a video camera. The advantage of this automatic multilevel thresholding approach is its robustness and adaptability when dealing with various ambient lighting conditions and spurious infrared noises. To extract the connected components of these touch blobs, a connected-component analysis procedure is applied to the bright pixels acquired by the previous stage. After extracting the touch blobs from each of the captured image frames, a blob tracking and event recognition process analyzes the spatial and temporal information of these touch blobs from consecutive frames to determine the possible touch events and actions performed by users. This process also refines the detection results and corrects for errors and occlusions caused by noise and errors during the blob extraction process. The proposed blob tracking and touch event recognition process includes two phases. First, the phase of blob tracking associates the motion correspondence of blobs in succeeding frames by analyzing their spatial and temporal features. The touch event recognition process can identify meaningful touch events based on the motion information of touch blobs, such as finger moving, rotating, pressing, hovering, and clicking actions. Experimental results demonstrate that the proposed vision-based finger detection, tracking, and event identification system is feasible and effective for multi-touch sensing applications in various operational environments and conditions

Evaluation of Physical Finger Input Properties for Precise Target Selection

The multitouch tabletop display provides a collaborative workspace for multiple users around a table. Users can perform direct and natural multitouch interaction to select target elements using their bare fingers. However, physical size of fingertip varies from one person to another which generally introduces a fat finger problem. Consequently, it creates the imprecise selection of small size target elements during direct multitouch input. In this respect, an attempt is made to evaluate the physical finger input properties i.e. contact area and shape in the context of imprecise selection

Evaluation of Physical Finger Input Properties for Precise Target Selection

The multitouch tabletop display provides a collaborative workspace for multiple users around a table. Users can perform direct and natural multitouch interaction to select target elements using their bare fingers. However, physical size of fingertip varies from one person to another which generally introduces a fat finger problem. Consequently, it creates the imprecise selection of small size target elements during direct multitouch input. In this respect, an attempt is made to evaluate the physical finger input properties i.e. contact area and shape in the context of imprecise selection

Multi-Touch

The main contribution in this project is first, by optimize the multi-touch simulation to demonstrate the multi input abilities and proceed with hardware implementation which will be in the second stage of this project, Final Year Project (FYP) II

Visualization of Tree-Structured Data Through a Multi Touch User Interface

This writing project examines different types of visualizations for tree-structured data sets. Visualizations discussed include link-node diagrams and treemap diagrams. Also discussed is recent innovations with regards to distinguishing multi touch from single touch technology. I explore the requirements needed to build a multi touch table top surface, and describe the process of building one. I then describe my proposed method of visualizing tree-structured data and how it can be implemented using Core Animation technology. I also propose a means of interacting with the data through a multi touch interface, and discuss which gestures can be used to navigate the visualization display

Expanding tangible tabletop interfaces beyond the display

L’augment de popularitat de les taules i superfícies interactives està impulsant la recerca i la innovació en una gran varietat d’àrees, incloent-­‐hi maquinari, programari, disseny de la interacció i noves tècniques d’interacció. Totes, amb l’objectiu de promoure noves interfícies dotades d’un llenguatge més ric, potent i natural. Entre totes aquestes modalitats, la interacció combinada a sobre i per damunt de la superfície de la taula mitjançant tangibles i gestos és actualment una àrea molt prometedora. Aquest document tracta d’expandir les taules interactives més enllà de la superfície per mitjà de l’exploració i el desenvolupament d’un sistema o dispositiu enfocat des de tres vessants diferents: maquinari, programari i disseny de la interacció. Durant l’inici d’aquest document s’estudien i es resumeixen els diferents trets característics de les superfícies interactives tangibles convencionals o 2D i es presenten els treballs previs desenvolupats per l’autor en solucions de programari que acaben resultant en aplicacions que suggereixen l’ús de la tercera dimensió a les superfícies tangibles. Seguidament, es presenta un repàs del maquinari existent en aquest tipus d’interfícies per tal de concebre un dispositiu capaç de detectar gestos i generar visuals per sobre de la superfície, per introduir els canvis realitzats a un dispositiu existent, desenvolupat i cedit per Microsoft Reseach Cambridge. Per tal d’explotar tot el potencial d’aquest nou dispositiu, es desenvolupa un nou sistema de visió per ordinador que estén el seguiment d’objectes i mans en una superfície 2D a la detecció de mans, dits i etiquetes amb sis graus de llibertat per sobre la superfície incloent-­‐hi la interacció tangible i tàctil convencional a la superfície. Finalment, es presenta una eina de programari per a generar aplicacions per al nou sistema i es presenten un seguit d’aplicacions per tal de provar tot el desenvolupament generat al llarg de la tesi que es conclou presentant un seguit de gestos tant a la superfície com per sobre d’aquesta i situant-­‐los en una nova classificació que alhora recull la interacció convencional 2D i la interacció estesa per damunt de la superfície desenvolupada.The rising popularity of interactive tabletops and surfaces is spawning research and innovation in a wide variety of areas, including hardware and software technologies, interaction design and novel interaction techniques, all of which seek to promote richer, more powerful and more natural interaction modalities. Among these modalities, combined interaction on and above the surface, both with gestures and with tangible objects, is a very promising area. This dissertation is about expanding tangible and tabletops surfaces beyond the display by exploring and developing a system from the three different perspectives: hardware, software, and interaction design. This dissertation, studies and summarizes the distinctive affordances of conventional 2D tabletop devices, with a vast literature review and some additional use cases developed by the author for supporting these findings, and subsequently explores the novel and not yet unveiled potential affordances of 3D-­‐augmented tabletops. It overviews the existing hardware solutions for conceiving such a device, and applies the needed hardware modifications to an existing prototype developed and rendered to us by Microsoft Research Cambridge. For accomplishing the interaction purposes, it is developed a vision system for 3D interaction that extends conventional 2D tabletop tracking for the tracking of hand gestures, 6DoF markers and on-­‐surface finger interaction. It finishes by conceiving a complete software framework solution, for the development and implementation of such type of applications that can benefit from these novel 3D interaction techniques, and implements and test several software prototypes as proof of concepts, using this framework. With these findings, it concludes presenting continuous tangible interaction gestures and proposing a novel classification for 3D tangible and tabletop gestures

Sensor Augmented Large Interactive Surfaces

Large interactive surfaces enable effective multi-user collaboration, but a majority of the current multi-touch systems are not truly multi-user. In this work we present a novel sensor-based approach for both user identification around a touch table and integration of unique gestures above the table. The work proposes the criteria for a successful and robust user identification system. The Cricket sensor based user identification system is integrated with an open source gesture recognition system Sparsh-UI to enable rapid multi-touch application development. Finally we evaluate the Cricket-based algorithm with contemporary multi-user, multi-touch systems and describe the various interaction affordances provided by the Cricket based user identification system

Multi-touch For General-purpose Computing An Examination Of Text Entry

In recent years, multi-touch has been heralded as a revolution in humancomputer interaction. Multi-touch provides features such as gestural interaction, tangible interfaces, pen-based computing, and interface customization – features embraced by an increasingly tech-savvy public. However, multi-touch platforms have not been adopted as everyday computer interaction devices; that is, multi-touch has not been applied to general-purpose computing. The questions this thesis seeks to address are: Will the general public adopt these systems as their chief interaction paradigm? Can multi-touch provide such a compelling platform that it displaces the desktop mouse and keyboard? Is multi-touch truly the next revolution in human-computer interaction? As a first step toward answering these questions, we observe that generalpurpose computing relies on text input, and ask: Can multi-touch, without a text entry peripheral, provide a platform for efficient text entry? And, by extension, is such a platform viable for general-purpose computing? We investigate these questions through four user studies that collected objective and subjective data for text entry and word processing tasks. The first of these studies establishes a benchmark for text entry performance on a multi-touch platform, across a variety of input modes. The second study attempts to improve this performance by iv examining an alternate input technique. The third and fourth studies include mousestyle interaction for formatting rich-text on a multi-touch platform, in the context of a word processing task. These studies establish a foundation for future efforts in general-purpose computing on a multi-touch platform. Furthermore, this work details deficiencies in tactile feedback with modern multi-touch platforms, and describes an exploration of audible feedback. Finally, the thesis conveys a vision for a general-purpose multi-touch platform, its design and rationale