Securing the Blind User Visualization and Interaction in Touch Screen

Blind users cannot use visual CAPTCHA and review of literature suggest that the existing audio CAPTCHAs have task success rate below 50 % for blind users. In this paper, we describe how blind student’s views external system (images) for academic purposes using an image map as a case study has been described. We proposed two interaction techniques which allow blind students to discover different parts of the system by interacting with a touch screen interface. An evaluation of our techniques reveals that (1) building an internal visualization, interaction technique and metadata of the external structure plays a vital role (2) blind students prefer the system to be designed based upon their behavioral model to easily access and build the visualization by their own and (3) to be an exact replica of visualization, the metadata of the internal visualization is to be provided either through audio cue or domain expert (educator). Participants who used touch screen are novice users, but they have enough experience on desktop computers using screen readers. The implications of this study to answer the research questions are discussed.