Perceptual transparency from image deformation

Abstract

Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid’s surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of “invisible” transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation.

Visual discomfort and flicker

“…This speculation is supported by the observation that, again unlike the fixed-phase patterns, the subjective naturalness in the random modulations monotonically increased as the blur increased (Fig. 5), and is consistent with the notion that the visual system has heuristic mechanisms for material perception using simple visual features correlated with the physical material profiles in nature (Fleming, 2014; Kawabe et al, 2015; Kawabe, Maruya, and Nishida, 2015; Marlow, Kim, and Anderson, 2012; Motoyoshi et al, 2007; Norman et al, 2007). …”

Animating static objects by illusion‐based projection mapping

“…Another line of vision science that influenced the development of Deformation Lamps is the research on material perception. Our recent study showed that dynamic deformation is a useful visual cue for human observers to see liquid‐like materials . As it had been shown that projection mapping was able to change the optical material properties of real objects, we attempted to change the mechanical material properties.…”

“…Our recent study showed that dynamic deformation is a useful visual cue for human observers to see liquid-like materials. 16,17 As it had been shown that projection mapping was able to change the optical material properties of real objects, we attempted to change the mechanical material properties. This was our initial motivation for developing Deformation Lamps.…”

Deformation Lamps

“…The image deformation due to refraction is a strong cue of the presence of transparent materials for computer vision [48]. For human vision, the impression of transparent liquid is generated solely by dynamic image deformation, and the deformation pattern could be a random modulation of a specific range of spatiotemporal frequencies [24].…”