Project: Perceptual qualities of materials - EU ITN PRISM

This project is part of the EU PRISM project. PhD student Fan Zhang investigates the underlying dimensions of material perception and is developing a “material probe” for perception research and design applications.

Project: Perceptual qualities of light - EU ITN PRISM

This project is part of the EU PRISM project. PhD student Tatiana Kartashova investigates the (in-)congruencies of the physical and visual light fields, plus novel methods to measure the visual light field in real scenes.

Project: The visual light field in real scenes

PhD student Ling Xia carries out this project. She investigates visual perception of light fields in real scenes using novel probing methods that allow for quantitative measurements. She is also developing novel metrics and measurement methods to describe light fields in a perceptually relevant manner, see f.i. her i-Perception paper.

Graduation projects.

I supervise graduation projects in Industrial Design Engineering such as for instance the development of light probes (see the image, a probe for fashion retail, and the accompanying LRT paper) the influence of lighting on product evaluation, the design of novel architectural elements containing lighting and the design of novel lighting concepts.

Installations museum het Prinsenhof.

We developed a lighting installation for the exhibition “Kijk, Jan Schoonhoven” and contributed to the accompanying book “Jan Schoonhoven, Delft”. As part of Ling Xia’s PhD project we developed a lighting test box for the permanent exhibition, demonstrating how light perception can be tested in  a real scene, using a simulated painting scene.

Visual Perception of paintings.

In several different projects we investigate which ingredients of paintings trigger our perceptions and how we might be able to enhance such perceptions. At the left we show a painting with a superposed “light probe” which obviously does not fit the scene, see our SPIE paper for more information. See also the website of my colleague Maarten Wijntjes.

Light, materials, shape and space

The research in my group focusses on design, perception and optics of light, materials, shape and space and all interactions between them. My past research in ecological optics focussed on optics and perception of reflectance (e.g. BRDF modeling), texture (e.g. illuminance flow), light (e.g. light fields) and shape (perception), see publications.

My own current research focusses on material mixing, lighting design theory, appearance metamery and materials and light in art. The work of the graduation and PhD students in my group is described below.

Material mixing

The BRDF of generic materials typically consist of several canonical reflectance lobes, e.g. a peach BRDF may contain a diffuse and a surface lobe, resulting in a combination of a matte and a velvety mode. Since the primary scattering direction is different for these modes, the salient features of the appearance modes usually show up at different locations too. Thus, similarly to descriptions of BRDFs as linear superpositions of scattering lobes, we can describe the appearance of 3D objects consisting of any materials as linear superpositions of 3D objects of different canonical materials, e.g. a glossy object as the superposition of a specular and a matte object. We use novel, optical mixing methods to generate such mixtures in a real setup using a semi-transparent mirror or on a computer screen as in the example at the right.

MixingmaterialsRevPP.pdf & SPIE2012_Pont.pdf

3D fine art reproduction - Océ Technologies

Since November 2015 I advise PhD student Willemijn Elkhuizen in her project on the reproduction of Fine Art including colour, texture, surface reflection and sub-surface reflections of multi-layered (translucent) materials. This project is a collaboration between Océ Technologies, several museums and Delft University of Technology.

Material rendering in still lifes - NWO NICAS

This project will be started in 2016. Its goal is to reach a better understanding of techniques, procedures for production, and uses of materials that constitute artistic mastery in still life painting and texture rendering; and to contribute significantly to the study of perceptual and cognitive aspects of art production.