[Fried89] distinguishes between conscious and preconscious visualization processes, where the preconscious processes are lower order processes, outside of voluntary control, very fast, and precede conscious processing. So, we can facilitate the effective use of visualization if we can increase the magnitude of the preconscious processing. A basic way to do this is to improve the visibility of the information embedded in the data.
One method already discussed, is to use brightness contrast rather than hue contrast pseudocoloring.
A second method is to take advantage of the sensitivity of the visual system to dynamic change. For example, rather than comparing two static images with different data (a conscious process), the two images might be rapidly flashed one after the other - this invokes the preconscious mechanism.
Animation can also be used to accomplish this. Difficult to detect objects can be seen more easily if they are in motion or being changed in other ways, e.g. color changes, size changes, etc. Dynamic changes can be used to bring out different aspects of the data.
A third method is to use, or avoid, specific orientations. From visual perception studies it has been shown that things don't look the same when their orientation is changed. For example, the two figures below are identical, except for the 45 degree rotation.
Since users may be trying to locate specific patterns that may be in different orientations, the ability to reorient the images is necessary.
Last modified on February 11, 1999, G.
Scott Owen, email@example.com
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