Abstract
Despite advanced image processing technology, digital cameras generally cannot handle the enormous range of light intensity that varies approximately 6 log-unit in everyday life. The human visual system is renowned for its dynamic regulation, rendering us to discriminate or detect subtle differences among visual inputs in the dynamically changing environment. Here we present a novel and strong illusory brightness perception that reflects neural mechanisms underlying this dynamic regulation of sensory inputs: motion signal from neighboring objects modulates perceived contrast of both the moving and the stationary objects against their background. Consequently, the stationary objects appear different from the moving objects even though both have the same physical light intensity. Experiments reveal that figure-ground segmentation, adaptation, attention, and motion-induced blindness cannot explain this illusion. Instead, normalization accompanied by motion signal is a plausible account for the illusory changes in perceptual experiences, observed in both stationary and moving objects. This novel brightness illusion suggests that brightness of an object is influenced by not just variations in surrounding light (i.e. simultaneous contrast), but also motion-induced neural signal in the context.
Meeting abstract presented at VSS 2012