Interactive tactile representations to support document accessibility for people with visual impairments

Abstract

Since the early beginnings of writing, humans exploited text layout as a primary means to facilitate reading access to a document. White space, spatial arrangements of text elements on the page, font sizes, and font weight are but a few examples. These features are judiciously employed to structure the document visually, in order to emphasize its logical structure. Sighted users enjoy the advantages that a well-designed layout confers, often without even realizing it; only when documents suer from illogical layoutsùe.g., missing white spaces or clear sectionsùdo users realize the benets of a well-organized layout. In contrast, it is the norm for visually impaired people to be provided little to no information about the spatial layout of documents. Braille text, sonification, and Text-To-Speech (TTS) can provide access to digital documents, albeit in a linearized form. This means that structural information, namely a bird's-eye-view, is mostly absent. For linear reading, this is a minor inconvenience that users can work around. However, spatial structures can be expected to strongly contribute to activities besides linear reading, such as document skimming, revising for a test, memorizing, understanding concepts, and text comparison. This lack of layout cues and structural information can provoke distinct types of reading hindrances. A reader with visual impairment may start reading multiple sidebar paragraphs before starting to read the main text without noticing, which is not optimal for reading a textbook. If readers want to revise a paragraph or access a certain element of the document, they must to go through each element on the page before reaching the targeted paragraph, due screen readers iterate through each paragraph linearly. This can be very frustrating and exhausting, especially if it would be required multiple times during a long study session. To identify different document's elements through a screen reader is also challenging. For example the user would not be able to distinguish between the main text and a sidebar paragraph. In the present dissertation, we portray in detail the research process where we investigated the access of digital textual contents by readers with visual impairments, we define strength and flaws of this content pursuit process. Then, we aim to provide answers and solutions related to the design and usability of touchable and auditory modalities to supply access to digital textual content to readers with visual impairments. We describe the observations and conclusions related to point out different features and characteristics of the reading process based on TTS screen readers for readers with visual impairments. We studied existing skim-reading strategies in sighted and visually impaired individuals, we identified key features of visual documents that allow sighted users to adopt a highly flexible and goal-oriented approach to skim-reading, elements which are mostly lost when documents are accessed in auditory form, as is commonly the case for readers with visual impairments. Different approaches have been proposed to combine electronic devices with tactile media, such as combining tactile elements with touch screen devices to produce interactive tactile maps. tactile and tangible elements have been added to enhance the accessibility of mainstream touch screen interfaces. We envisioned, designed and developed through three different design stages Tactile sheets, a system which has worked on conveying information about visual layout of digital textual documents, this system is based on differentiated tactile elements layouted on teh surface of overlays; these overlays are placed on a touchscreen tablet, creating a tactile interface which makes possible the users to navigate through a document, recongnize its layout, to acquire implicit information related to the position and clasification of different document elements like titles, paragraphs, tables or highlighted text, and access its content through auditory feedback. As a system's design iteration we have introduced an automatic identification method which allows the user to update the digital content in relation to a concrete tactile overlay placed on the tochscreen device, this improved the usability of tactile overlays and granted a innovative lebel of interactivity and fluidity to the tactual pages interface system. This solution was assessed conducting a set of studies with visually impaired participants who were requested to perform different tasks with our system and with auditory screen readers. The approach received positive quantitative and qualitative assessments and was preferred by most participants over the screen readers. Our experimental setting demonstrated the feasibility of a multimodal interface dedicated for visually impaired users, modalities are based on tactual and auditory channels. We also demonstrated that this interface can convey a concrete flow of information to the users, and those users can interact with that information within teh context of the mentioned interface. The possibility to generate a refreshable interface based on a mean initially conceived as a fixed setting like tactile cardboard overlays was proved. This feature has been obtained utilizing affordable resources and through an easily replicable method. Thus, we consider that the automatic identified tactile overlays approach is a promising method for touch screens accessibility, that improves the usability and gives the users more control over the touch screen and provides more content on the layout structure and element types of a text document.