Current interactive media presentations of textiles provide an impoverished communication of their 'textile hand', that is their weight, drape, how they feel to touch. These are complex properties experienced through the visual, tactile, auditory and proprioceptive senses and are currently lost when textile materials are presented in interactive video. This paper offers a new perspective from which the production of multi-touch interactive video representations of the tactile qualities of materials is considered. Through an understanding of hand properties of textiles and how people inherently touch and handle them, we are able to develop methods to animate and bring these properties alive using design methods. Observational studies were conducted, noting gestures consumers used to evaluate textile hand. Replicating the appropriate textile deformations for these gestures in interactive video was explored as a design problem. The resulting digital textile swatches and their interactive behavior were then evaluated for their ability to communicate tactile qualities similar to those of the real textiles.

Tactile perceptions of digital textiles: a design research approach

We propose a complete image-based process that facilitates recovery of both gross-scale geometry and local surface structure to create highly detailed 3D models of building facades from photographs. We approximate both albedo and sufficient local geometric structure to compute complex self-shadowing effects, and fuse this with a gross-scale 3D model. Our approach yields a perceptually high-quality model, imparting the illusion of measured reflectance. The requirements of our approach are that image capture must be performed under diffuse lighting and surfaces in the images must be predominantly Lambertian. Exemplars of materials are obtained through surface depth hallucination, and our novel method matches these with multi-view image sequences that are also used to automatically recover 3D geometry. In this paper we illustrate the effictiveness of our approach through visually realistic reconstructions of historic buildings in two test cases, together with a table showing the breakdown of effort required to reconstruct each.

Relightable Buildings from Images

Acquisition of displacement and albedo maps for full building facades is a difficult problem and traditionally achieved through a labor intensive artistic process.In this paper, we present a material appearance transfer method, Transfer by Analogy, designed to infer surface detail and diffuse reflectance for textured surfaces like the present in building facades. We begin by acquiring small exemplars (displacement and albedo maps), in accessible areas, where capture conditions can be controlled. We then transfer these properties to a complete photo-texture constructed from reference images and captured under diffuse daylight illumination.Our approach allows super-resolution inference of albedo and displacement from information in the photo-texture. When transferring appearance from multiple exemplars to facades containing multiple materials, our approach also sidesteps the need for segmentation.We show how we use these methods to create relightable models with a high degree of texture detail, reproducing the visually rich self-shadowing effects that would normally be difficult to capture using just simple consumer equipment.

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Transfer of albedo and local depth variation to photo-textures

Physically-based rendering in Computer Graphics requires the knowledge of material properties other than 3D shapes, textures and colors, in order to solve the rendering equation A number of material models have been developed, since no model is currently able to reproduce the full range of available materials Although only few material models have been widely adopted in current rendering systems, the lack of standardisation causes several issues in the 3D modelling
workflow, leading to a heavy tool dependency of material appearance In industry, final decisions about products are often based on a virtual prototype, a crucial step for the production pipeline, usually developed by a collaborations among several
departments, which exchange data Unfortunately, exchanged data often tends to differ from the original, when imported into a different application As a result, delivering consistent visual results requires time, labour and computational cost
This thesis begins with an examination of the current state of the art in material appearance representation and capture, in order to identify a suitable strategy to tackle material appearance consistency Automatic solutions to this problem are suggested in this work, accounting for the constraints of real-world scenarios, where the only available information is a reference rendering and the renderer used to obtain it, with no access to the implementation of the shaders In particular, two image-based frameworks are proposed, working under these constraints
The first one, validated by means of perceptual studies, is aimed to the remapping of BRDF parameters and useful when the parameters used for the reference rendering are available The second one provides consistent material appearance across different renderers, even when the parameters used for the reference are unknown It allows the selection of an arbitrary reference rendering tool, and manipulates the output of other renderers in order to be consistent with the reference

Image based surface reflectance remapping for consistent and tool independent material appearence

While the concept of photorealism has important applications in computer graphics, the research community has not agreed on a definition of photorealism that specifies how to measure it. We employed two different test procedures, which correspond to different use scenarios, in order to determine the photorealism of a virtual reconstruction of a historic Viking building using two different lighting techniques. Even in this limited case, the measured degree of photorealism appears to depend on both the test procedure as well as the tested imagery; therefore, we conclude that there is no single measure of photorealism that is appropriate in all situations. Instead, photorealism appears to be a multifaceted phenomenon that requires different measurement procedures for different use scenarios. CR Categories: I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Color, shading, shadowing, and texture; H.1.2 [Models and Principles]: User/Machine Systems—Human factors

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Why a Single Measure of Photorealism Is Unrealistic

This paper evaluates a new method for capturing surfaces with variations in albedo, height, and local orientation using a standard digital camera with three flash units. Similar to other approaches, captured areas are assumed to be globally flat and largely diffuse. Fortunately, this encompasses a wide array of interesting surfaces, including most materials found in the built environment, e.g., masonry, fabrics, floor coverings, and textured paints. We present a case study of naive subjects who found that surfaces captured with our method, when rendered under novel lighting and view conditions, were statistically indistinguishable from photographs. This is a significant improvement over previous methods, to which our results are also compared.

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Greg Ward

Papers

A case study evaluation: perceptually accurate textured surface models