Contribuições para interação pelo olhar com teclados virtuais
obtenção do título de Doutor em Ciências Programa: Ciência da Computação Palavras-chave: interação pelo olhar, rastreamento do olhar, acessibilidade, interfaces para pessoas com deficiência física, efeito gap, digitação pelo olhar. Abstract Diaz Tula, A. Contributions for gaze interaction with virtual keyboards. Tese (Doutorado) -This PhD thesis lays in the context of gaze-based interaction. Gaze-based interfaces allows the user to control a computer using his/her eye movements. Gaze
... ts. Gaze interaction is specially useful for people with physical disabilities who cannot use conventional devices (such as a keyboard and/or mouse) to communicate. Entering text by gaze (also known as eye typing) is a very important activity and the main focus of this dissertation. The most common eye typing technique uses a virtual keyboard, where the letters are selected by dwell time. Though simple, this interaction technique suffers from involuntary activations (known as the Midas' touch problem) for short dwell times (shorter than 500 ms). On the other hand, with longer dwell times the interaction becomes slow. Alternatives to dwell time are discrete and continuous gaze gestures. The use of discrete gaze gestures reduces the Midas' touch problem, but its performance is slower compared to dwell time. When using continuous gaze gestures, the user gaze is always controlling the interface. A recently proposed technique called "context switching" avoids the Midas touch problem by mapping selection to a single saccade. Furthermore, with this technique the users can keep their rhythm of interaction without adjusting any parameter of the interface. This PhD thesis aims at improving the usability and user experience in gaze interaction with virtual keyboards. The objectives are: to investigate the relationship between contrast manipulation of visual stimuli and saccadic reaction time, to facilitate eye movements and make the interaction faster and more comfortable; to propose and investigate new extensions and applications of the context switching paradigm, in order to reduce the Midas touch problem and generalize the extensions to other tasks such as browsing and selection; and to develop new methods of eye typing that can improve typing performance without increasing the user workload, while keeping the interaction simple and easy to learn. Several user studies were designed and conducted to evaluate the methods and models proposed in this thesis. The data (both quantitative and qualitative) collected in the experiments is rigorously analysed using statistical methods. The original contributions of this thesis are: the proposal and investigation of the gradient gap effect as a visual feedback to facilitate the execution of saccadic movements during gaze interaction; the proposal and investigation of two extensions to the context switching paradigm: dynamic contexts that improve the utilization of the screen space while keeping a low selection error rate, and meta-keys for browsing and executing general-purpose commands; and the proposal and evaluation of AugFix , a new method that improves eye typing speed and user experience without increasing the cognitive load, that can be used with virtual keyboards controlled by both dwell time and context v vi switching.