  Light projection is a powerful technique to edit appearances of objects in
the real world. Based on pixel-wise modification of light transport, previous
techniques have successfully modified static surface properties such as surface
color, dynamic range, gloss and shading. Here, we propose an alternative light
projection technique that adds a variety of illusory, yet realistic distortions
to a wide range of static 2D and 3D projection targets. The key idea of our
technique, named Deformation Lamps, is to project only dynamic luminance
information, which effectively activates the motion (and shape) processing in
the visual system, while preserving the color and texture of the original
object. Although the projected dynamic luminance information is spatially
inconsistent with the color and texture of the target object, the observer's
brain automatically com- bines these sensory signals in such a way as to
correct the inconsistency across visual attributes. We conducted a
psychophysical experiment to investigate the characteristics of the
inconsistency correction, and found that the correction was dependent
critically on the retinal magnitude of inconsistency. Another experiment showed
that perceived magnitude of image deformation by our techniques was
underestimated. The results ruled out the possibility that the effect by our
technique stemmed simply from the physical change of object appearance by light
projection. Finally, we discuss how our techniques can make the observers
perceive a vivid and natural movement, deformation, or oscillation of a variety
of static objects, including drawn pictures, printed photographs, sculptures
with 3D shading, objects with natural textures including human bodies.
