Survey of Models for Acquiring the Optical Properties of Translucent Materials

Abstract

The outset of realistic rendering is a desire to reproduce the appearance of the real world. Rendering techniques therefore operate at a scale corresponding to the size of objects that we observe with our naked eyes. At the same time, rendering techniques must be able to deal with objects of nearly arbitrary shapes and materials. These requirements lead to techniques that oftentimes leave the task of setting the optical properties of the materials to the user. Matching the appearance of real objects by manual adjustment of optical properties is however nearly impossible. We can render objects with a plausible appearance in this way but cannot compare the appearance of a manufactured item to that of its digital twin. This is especially true in the case of translucent objects, where we need more than a goniometric measurement of the optical properties. In this survey, we provide an overview of forward and inverse models for acquiring the optical properties of translucent materials. We map out the efforts in graphics research in this area and describe techniques available in related fields. Our objective is to provide a better understanding of the tools currently available for appearance specification when it comes to digital representations of real translucent objects.

Translucency perception: A review

“…Although computer graphics is often used as a tool for studying translucency perception (e.g., Urban et al, 2019;Xiao et al, 2014), perceiving translucency and accurate reproduction of translucent appearance is itself an important topic for the computer graphics community, especially when photorealism is at stake (Frisvad et al, 2020). One of the most significant, yet challenging, topics is accurate rendering of the human skin, which not only plays an essential role in the movies, video games, and other segments of the entertainment industry, but also extends to the fields of computer vision (face detection and edge detection; Gkioulekas et al, 2015), medicine, and cosmetology (Igarashi et al, 2005;Li et al, 2018).…”

“…One of the most significant, yet challenging, topics is accurate rendering of the human skin, which not only plays an essential role in the movies, video games, and other segments of the entertainment industry, but also extends to the fields of computer vision (face detection and edge detection; Gkioulekas et al., 2015 ), medicine, and cosmetology ( Igarashi et al., 2005 ; Li et al., 2018 ). Although considerable progress has been made in this direction, skin rendering , which inherently implies the accurate reproduction of translucent appearance, is a topic of active ongoing research ( d’Eon & Irving, 2011 ) and remains especially challenging owing to the multilayer nature of a human skin ( Frisvad et al., 2020 ; Nunes et al., 2019 ).…”

Computing the Bidirectional Scattering of a Microstructure Using Scalar Diffraction Theory and Path Tracing

“…This significantly limits the types of surfaces that one can faithfully model. An extensive body of work provides extension of this outset and models more advanced surface types and light scattering phenomena [FJM∗20]. An important extension is the use of explicitly defined microgeometry based on Kirchhoff theory [Kaj85].…”

Analysis of the Visual Appearance of AISI 430 Ferritic Stainless Steel Flat Sheets Manufactured by Cool Rolling and Bright Annealing

“…The optical scattering distribution function is a topic of interest in engineering applications such as the manufacture of high-quality mirrors for scientific use [8], and knowledge of this topic has been supported by the development of infographics and surface rendering [9][10][11][12]. A number of theoretical approaches developed to model the bidirectional reflectance distribution function (BRDF) and the most complete bidirectional scattering-surface reflectance distribution function (BSSRDF) is presented in the review by Frisvad et al [13], which provides a comprehensive analysis of the approaches that can be found in the literature.…”

“…2 of 13 where S q stands for the root mean square height of the surface topography, θ i is the incidence angle of the light on the surface, and λ is the light wavelength. Other models, based on the Beckmann-Kirchhoff theory, approximate the topography using a normal distribution of microfacets and are better suited to modelling the optical scattering produced by surfaces with roughness on the micro/milli scale [11,[15][16][17][18][19].…”