Perceptual Invariance of Nonlinear Focus+Context Transformations
Keith Lau and Ronald A. Rensink and Tamara Munzner
First Symposium on Applied Perception in Graphics and Visualization,
pages 65-72
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Abstract
Paper
Abstract
Focus+Context techniques are commonly used in visualization systems to
simultaneously provide both the details and the context of a
particular dataset. This paper proposes a new methodology to
empirically investigate the effect of various Focus+Context
transformations on human perception. This methodology is based on the
shaker paradigm, which tests performance for a visual task on an
image that is rapidly alternated with a transformed version of itself.
An important aspect of this technique is that it can determine two
different kinds of perceptual cost: (i) the effect on the perception
of a static transformed image, and (ii) the effect of the dynamics of
the transformation itself. This technique has been successfully
applied to determine the extent to which human perception is invariant
to scaling and rotation [Rensink 2004]. In this paper, we extend
this approach to examine nonlinear fisheye
transformations of the type typically used in a Focus+Context
system. We show that there exists a no-cost zone where performance
is unaffected by an abrupt, noticeable fisheye transformation, and
that its extent can be determined. The lack of perceptual cost in
regards to these sudden changes contradicts the belief that they are
necessarily detrimental to performance, and suggests that smoothly
animated transformations between visual states are not always
necessary. We show that this technique also can map out low-cost
zones where transformations result in only a slight degradation of
performance. Finally, we show that rectangular grids have no
positive effect on performance, acting only as a form of visual
clutter.
These results therefore demonstrate that the
perceptual costs of nonlinear transformations can be successfully
quantified. Interestingly, they show that some kinds of sudden
transformation can be experienced with minimal or no perceptual cost.
This contradicts the belief that sudden changes are necessarily
detrimental to performance, and suggests that smoothly animated
transformations between visual states are not always necessary.
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Last modified: Wed Sep 20 19:12:41 PDT 2006