Evaluation of the Touch Tablet as a Command and Control Input Device

摘要

Four studies conducted to evaluate the touch tablet as an input device to support operator computer communication are presented. Tasks performed by operators in these studies included text editing, two-dimensional compensatory tracking, alphameric and numeric data entry, an analog of a command and control composite task consisting of single function selection, and multiple function selection and data entry. An absolute mode of tablet operation, in which the table generates x-y coordinates representing the point of touch relative to the physical surface area of the tablet, proved to be superior to a relative mode of operation, in which the tablet is programmed to respond to changes in x-y coordinates, irrespective of the area of the tablet surface activated. Significant variation in speed and accuracy of performance was observed across a variety of tasks as a function of the mechanism used to signal the computer to accept data emanating from the tablet. A lift-off only mode produced the most rapid rate of response but also the most errors. The most efficient method was the use of an off-table response key to signal the computer to accept the x-y coordinate generated from the touch tablet at each response. Stylus type also proved to be an important parameter of tablet operation with the use of a hand-held stylus superior in both speed and accuracy to the use of the unaided finger. Performance with the tablet appears to be consistent, at least with respect to speed of responding, across a wide range of tasks. Keywords: Light pens, Mechanical mouse, Lightweight modular display system(LMDS), Touch screens, Human-computer interface. (KR)