
Hybrid images paper by Aude Oliva, MIT; Antonio Torralba, MIT; and Philippe G. Schyns University of Glasgow.
compelling displays in which the image appears to change as the viewing distance changes. We show that by taking into account perceptual grouping mechanisms it is possible to build compelling hybrid images with stable percepts at each distance.
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Hybrid images, however, contain two coherent global image interpretations, one of which is of the low spatial frequencies, the other of high spatial frequencies.
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For a given distance of viewing, or a given temporal frequency a particular band of spatial frequency dominates visual processing. Visual analysis of the hybrid image still unfolds from global to local perception, but within the selected frequency band, for a given viewing distance, the observer will perceive the global structure of the hybrid first, and take an additional hundred milliseconds to organize the local information into a coherent percept (organization of blobs if the image is viewed at a far distance, or organization of edges for close viewing).
Very cool stuff.

Related: Illusions, Optical and Other – How Our Brain Resolves Sight – Seeing Patterns Where None Exists – Magenta is a Color – posts on scientific explanations of what we experience – Computational Visual Cognition Laboratory at MIT