Automatic and self-paced scanning for alternative text entry

This paper introduces a novel software for alternative text entry implemented as part of the framework of the HAndsfree Mouse COntrol System HaMCoS. The application lets the user 'write' individual characters as well as completions of unfinished words by iteratively selecting one of multiple options. In addition to representing an instance of conventional scanning (also called indirect text entry), where a selection marker is automatically advanced to the next available option after a certain dwell period has elapsed, the program may be configured to have the user explicitly trigger any marker changes. One main purpose of this paper is to evaluate the two scanning techniques, automatic and self-paced , not only regarding the achievable entry rate, but also concerning usability. With this in mind, several comparative experiments which involve transcribing a specific text fragment have been conducted. The results demonstrate that both variants have advantages and disadvantages. In fact, it turned out that, although being more stressful for the user, automatic scanning allowed faster operation. Besides, it can be shown that the presented software application indeed is a promising alternative for someone who is unable to use any form of direct text entry.