Abstract
Mirror materials (perfect specular surfaces such as polished metal) and glass materials (transparent and refraction media) are quite commonly encountered in everyday life. The human visual system can discriminate these complex distorted images formed by reflection or transmission of the surrounding environment even though they do not intrinsically possess surface colour. In this study, we determined the cues that aid mirror and glass discrimination. From video analysis, we found that glass objects have more opposite motion components relative to the direction of object rotation. Then, we hypothesised a model developed using motion transparency because motion information is not only present on the front side, but also on the rear side of the object surface in the glass material object. In materials judging experiments, we found that human performance with rotating video stimuli is higher than that with static stimuli (simple images). Subsequently, we compared the developed model derived from motion coherency to human rating performance for transparency and specular reflection. The model sufficiently identified the different materials using dynamic information. These results suggest that the visual system relies on dynamic cues that indicate the difference between mirror and glass.
Highlights
Visual information reaching the human retina potentially contains temporal components due to the motion of objects and/or observers
This study focuses on mirror and glass materials, because both are, as stated above, quite common in everyday life and easy to discriminate under natural conditions, but both are determined only based on visual cues existing in the image distorted by the reflection or transmission
We suggest that this dynamic cue from the video can somehow be detected by the visual system, for example, through perception of motion transparency, and be used for perception of smooth surface materials and distinction between mirror and glass
Summary
Visual information reaching the human retina potentially contains temporal components due to the motion of objects and/or observers. The type and degree of distortion varies significantly according to the 3D shape of the object, which is generally unknown and should be recovered by the visual system Even though it should be difficult for the visual system to discriminate mirror and glass, this is quite easy for humans under everyday conditions. It was previously unknown that dynamic cues are used to directly distinguish mirror and glass, some related cues have been reported for specular reflected or transparent objects. Fleming et al.[21] have reported that the distortion field derived from the refractive index of a thick transparent object (glass) determines human perception when judging refractive indices This provides a cue for perceiving glass, this perception might arise because of similar distorted images derived from the specular surface depending on the object’s shape, motion, and surrounding environment. These previously proposed cues provided by motion do not directly explain the mechanism used to distinguish mirror and glass
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
