A camera-joystick for sound-augmented non-visual navigation and target acquisition: a case study

Abstract

This paper presents the results of a comparative study of user input with a camera-joystick and a manual joystick used in a target acquisition task when neither targets nor pointer could be perceived visually. The camera-joystick is an input technique in which each on-screen item is accessible from the center with a predefined vector of head motion. Absolute pointing was implemented with an acceleration factor of 1.7 and a moving average on 5 detected head positions. The underlying assumption was that, in order to provide a robust input for blind users, the interaction technique has to be based on perceptually welldiscriminated human movements, which compose a basic framework of an accessible virtual workspace demanding minimum external auxiliary cues. The target spots, having a diameter of 35 mm and a distance between the centers of adjacent spots of 60 mm, were arranged in a rectangular grid of 5 rows by 5 columns. The targets were captured from a distance of 600 mm. The results have shown that the camera input is a promising technique for non-visual human-computer interaction. The subjects demonstrated, more than twice, better performance in the target acquisition task with the camera-joystick versus the manual joystick. All the participants reported that the camerajoystick was a robust and preferable input technique when visual information was not available. Blind interaction techniques could be significantly further improved allowing a user-dependent activation of the navigational cues to better coordinate feedbacks with exploratory behavior.

Emerging issues and current trends in assistive technology use 2007–2010: practising, assisting and enabling learning for all

“…They propose an educational software accessibility checklist which is intended to be used by teachers who may have little experience of children with limited vision, and covering areas such as general readability, working field extension and position, menu location and coherence, characters and colour. A team of researchers in Finland (Evreinova, Evreinov & Raisamo 2008) looked at alternative input devices, a camera joystick and a manual version, as part of ongoing work in this area. The efficacy of the devices for user input was compared in a target acquisition task, where neither the targets nor any pointers were available visually.…”