Wednesday, February 20, 2008

Inspiration: ZoomNavigator (Skovsgaard, 2008)

Following up on the StartGazer text entry interface presented in my previous post, another approach to using zooming interfaces is employed in the ZoomNavigator (Skovsgaard, 2008) It addresses the well known issue of using gaze as input on traditional desktop systems, namely inaccuracy and jitter. Interesting solution which relies on dwell-time execution compared to the EyePoint system (Kumar&Winograd, 2007) which is described in the next post.

The goal of this research is to estimate the maximum amount of noise of a pointing device that still makes interaction with a Windows interface possible. This work proposes zoom as an alternative activation method to the more well-known interaction methods (dwell and two-step-dwell activation). We present a magnifier called ZoomNavigator that uses the zoom principle to interact with an interface. Selection by zooming was tested with white noise in a range of 0 to 160 pixels in radius on an eye tracker and a standard mouse. The mouse was found to be more accurate than the eye tracker. The zoom principle applied allowed successful interaction with the smallest targets found in the Windows environment even with noise up to about 80 pixels in radius. The work suggests that the zoom interaction gives the user a possibility to make corrective movement during activation time eliminating the waiting time found in all types of dwell activations. Furthermore zooming can be a promising way to compensate for inaccuracies on low-resolution eye trackers or for instance if people have problems controlling the mouse due to hand tremors.

The sequence of images are screenshots from ZoomNavigator showing
a zoom towards a Windows file called ZoomNavigator.exe.

The principles of ZoomNavigator are shown in the figure above. Zooming is used to focus on the attended object and eventually make a selection (unambiguous action). ZoomNavigator allows actions similar to those found in a conventional mouse. (Skovsgaard, 2008) The system is described in a conference paper titled "Estimating acceptable noise-levels on gaze and mouse selection by zooming" Download paper (pdf)

Two-step zoom
The two-step zoom activation is demonstrated in the video below by IT University of Copenhagen (ITU) research director prof. John Paulin Hansen. Notice how the error rate is reduced by the zooming style of interaction, making it suitable for applications with need for detailed discrimination. It might be slower but error rates drops significantly.

"Dwell is the traditional way of making selections by gaze. In the video we compare dwell to magnification and zoom. While the hit-rate is 10 % with dwell on a 12 x 12 pixels target, it is 100 % for both magnification and zoom. Magnification is a two-step process though, while zoom only takes on selection. In the experiment, the initiation of a selection is done by pressing the spacebar. Normally, the gaze tracking system will do this automatically when the gaze remains within a limited area for more than approx. 100 ms"

For more information see the publications of the ITU.

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