High precision touchscreens: design strategies and comparisons with a mouse

Abstract

Three studies were conducted comparing speed of performance, error rates, and user preference ratings for three selection devices. The devices tested were a touchscreen, a touchscreen with stabilization (stabilization software filters and smooths raw data from hardware), and a mouse. The task was the selection of rectangular targets 1, 4, 16, and 32 pixels per side (0.4x0.6, 1.7x2.2, 6.9x9.0, 13.8x17.9 mm respectively). Touchscreen users were able to point at single pixel targets, thereby countering widespread expectations of poor touchscreen resolution. The results show no difference in performance between the mouse and touchscreen for targets ranging from 32 to 4 pixels per side. In addition, stabilization significantly reduced the error rates for the touchscreen when selecting small targets. These results imply that touchscreens, when properly used, have attractive advantages in selecting targets as small as 4 pixels per size (approximately onequarter of the size of a single character). A variant of Fitts' Law is proposed to predict touchscreen pointing times. Ideas for future research are also presented. Overview Many pointing devices are available for use with computers, but none are as natural to use as the touchscreen. Pointing at an item, or touching it, is one of the most natural ways to select it. Touchscreens allow the software designer to take advantage of this convenient selection method by having the users simply touch the item they are interested in.

A Comparison of Direct and Indirect Multi-touch Input for Large Surfaces

“…Second, we used a vision-based input technology which is more sensitive to touches and capable of detecting non-finger contacts, too. In specific, we observed that lifting the finger off the surface sometimes caused the selected target to move as described by Sears et al [23]. Therefore, it was not properly aligned with the dock anymore which was counted as dragging error.…”

“…(b) Indirect multi-touch: separate output with display of hand contours (a) Direct multi-touch: input and output space coincide Direct versus indirect input has been studied widely for single-pointer interaction, comparing indirect input devices with direct-touch or pen input (e.g., [20,23]). A recent study is close to ours in spirit, as it focuses on a single in-put technology, here a stylus pen, which is compared for direct and indirect interaction showing that indirect use can perform as well for certain tasks [8].…”

The performance of hand postures in front- and back-of-device interaction for mobile computing

“…Prior finger-based pointing techniques suffered from two problems, which Shift remedies: the occlusion caused by the hand, and the lack of precision caused by fingers that are larger than many targets. Prior to Shift, the Offset Cursor was a popular design that placed the selection point a standard distance above the finger contact point (Potter et al, 1988;Sears and Shneiderman, 1991). But the Offset Cursor required users to ''aim low'' in anticipation of the constant offset, ruining the possibility of direct-touch for large targets.…”

“…In order to isolate the physical performance of hand postures on a mobile device, we had to create an experiment apparatus that circumvented the two wellknown perceptual problems of direct-touch on touch screens, namely the occlusion caused by the user's hand and the unwieldy ''fat finger'' that creates an uncertain touch location (Potter et al, 1988;Sears and Shneiderman, 1991;Vogel and Baudisch, 2007;Wigdor et al, 2007). We argue that innovations in display and sensing technologies will continue to ameliorate these problems, and therefore they should not confound our results.…”

Multiple Resource Host Architecture (MRHA) for the Mobile Detection Assessment Response System (MDARS) Revision A

“…Applicable comparative studies on the candidate devices were reviewed (Albert, 1982;Helander, 1988;Karat, et al, 1986;Sears, Shneiderman, 1991) and user feedback was solicited. Prototype mouse and trackball interfaces have been developed with the Supervisor Display.…”