Colloquium Cognitive Systems
Visual Perception of Materials and their Properties
Prof. Dr. Roland Fleming, Uni Giessen
Abstract: Under typical viewing conditions, human observers effortlessly recognize materials and infer their physical, functional and multisensory properties at a glance. Without touching materials, we can usually tell what they would feel like, and we enjoy vivid visual intuitions about how they are likely to respond to external forces, allowing us to predict their behaviour as we interact with them. These achievements are impressive because the retinal image of a material results from extremely complex physical processes (e.g. sub-surface light transport; visco-elastic fluid flow). Due to their extreme diversity, mutability and complexity, materials represent a particularly challenging class of visual stimuli, so understanding how we recognize materials, estimate their properties, predict their behaviour, and interact with them could give us more general insights into visual processing and internal models of the physical world. What is ‘material appearance’, and how do we measure it and model it? How are material properties estimated and represented? Discussing these questions causes us to scrutinize the basic assumptions of ‘mid-level vision’ that prevail in theories of human vision, and gives hints at how to build a machine vision system that could learn materials from passive and active observations.
Bio: Roland Fleming read PPP at Oxford, and did his PhD at MIT. After a postdoc at the Max Planck Institute for Biological Cybernetics, he joined Giessen University, where he is currently the Kurt Koffka Professor of Experimental Psychology. His research combines psychophysics, neural modelling, computer graphics and image analysis to understand how the brain estimates the physical properties of objects. In 2013 he was awarded the Young Investigator Award by the Vision Sciences Society, and in 2016 an ERC Consolidator Award for the project “SHAPE: On the perception of growth, form and process”.