Anatomically accurate modeling and rendering of the human eye

Recovering anatomical features of organic materials is a challenging issue. The human eye, as an important part of the non verbal communication, needs to be accurately modeled and rendered to increase the realism of virtual characters. The recent improvements of the graphics hardware offer the opportunity of rendering complex organic materials, following correct anatomical properties. We propose a novel method that allows to recover the iris structure and scattering features from a single eye photograph. In this aim, we developed a method to unrefract iris photographs. We model the iris using the Subsurface Texture Mapping representation which allows to describe the relieves of the human iris. Finally, we introduce a refraction function for accurate real-time rendering of the eye, accounting for the refraction of the light at the corneal interface

Appearance Modeling of Living Human Tissues

This is the peer reviewed version of the following article: Nunes, A.L.P., Maciel, A., Meyer, G.W., John, N.W., Baranoski, G.V.G., & Walter, M. (2019). Appearance Modeling of Living Human Tissues, Computer Graphics Forum, which has been published in final form at https://doi.org/10.1111/cgf.13604. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingThe visual fidelity of realistic renderings in Computer Graphics depends fundamentally upon how we model the appearance of objects resulting from the interaction between light and matter reaching the eye. In this paper, we survey the research addressing appearance modeling of living human tissue. Among the many classes of natural materials already researched in Computer Graphics, living human tissues such as blood and skin have recently seen an increase in attention from graphics research. There is already an incipient but substantial body of literature on this topic, but we also lack a structured review as presented here. We introduce a classification for the approaches using the four types of human tissues as classifiers. We show a growing trend of solutions that use first principles from Physics and Biology as fundamental knowledge upon which the models are built. The organic quality of visual results provided by these Biophysical approaches is mainly determined by the optical properties of biophysical components interacting with light. Beyond just picture making, these models can be used in predictive simulations, with the potential for impact in many other areas

Interactive Rendering of Scattering and Refraction Effects in Heterogeneous Media

In this dissertation we investigate the problem of interactive and real-time visualization of single scattering, multiple scattering and refraction effects in heterogeneous volumes. Our proposed solutions span a variety of use scenarios: from a very fast yet physically-based approximation to a physically accurate simulation of microscopic light transmission. We add to the state of the art by introducing a novel precomputation and sampling strategy, a system for efficiently parallelizing the computation of different volumetric effects, and a new and fast version of the Discrete Ordinates Method. Finally, we also present a collateral work on real-time 3D acquisition devices

Subsurface Texture Mapping

Subsurface scattering within translucent objects is a complex phenomenon. Designing and rendering this kind of material requires a faithful description of their aspects as well as a realistic simulation of their interaction with light. This paper presents an efficient rendering technique of multilayered translucent objects. We present a new method for modeling and rendering such complex organic materials made up of multiple layers of variable thickness. Based on the relief texture mapping algorithm, our method calculates the single scattering contribution for this kind of material in real-time using commodity graphics hardware. Our approach needs the calculation of distances traversed by a light ray through a translucent object. This calculation is required for evaluating the attenuation of light within the material. We use a surface approximation algorithm to quickly evaluate these distances. Our whole algorithm is implemented using pixel shaders. \\ La diffusion de la lumière l'intérieur de matériaux participants est un phénomène complexe. Pour modéliser et rendre de tels matériaux, il est nécessaire d'avoir une description adaptée de ceux-ci ainsi qu'une simulation réaliste de leurs interactions avec la lumière. Ce papier présente une technique de rendu adaptée aux matériaux multicouches. Cette nouvelle méthode permet de modéliser des matériaux organiques complexes composés de couches multiples à épaisseur variable. Basée sur l'algorithme du relief mapping, notre méthode permet le calcul temps réel de la diffusion simple pour ce type de matériau, et ce en exploitant les performances des cartes graphiques. Notre méthode nécessite le calcul des distances parcourues par la lumière l'intérieur des diffrentes couches du matériau. Ce calcul est nécessaire pour l'évaluation de l'atténuation de la lumière l'intérieur du matériau. Nous proposons d'utiliser un algorithme d'approximation de surface pour raliser ce calcul rapidement. Notre algorithme est implementé à l'aide de pixel shader

Subsurface Texture Mapping

Designing and rendering translucent material requires a faithful description of its aspects as well as a realistic simulation of its interaction with light. A new method for modeling and rendering complex organic materials made up of multiple layers of variable thickness uses simple texture-mapping principles and a single-scattering computation. © 2008 IEEE

Subsurface texture mapping

Designing and rendering translucent material requires a faithful description of its aspects as well as a realistic simulation of its interaction with light. A new method for modeling and rendering complex organic materials made up of multiple layers of variable thickness uses simple texture-mapping principles and a single-scattering computation

Subsurface Texture Mapping

International audienc

Modélisation et rendu de matériaux organiques

Subsurface scattering has been an intensive research area over the last decades. The goal of this field is to simulate how light interacts with the particles within the object. The computation of subsurface scattering is very complex in the general case, and can require several hours even on high performance computers. This thesis presents a solution for modeling and real-time rendering of complex organic materials. Subsurface Texture Mapping is a user-friendly modeling method for translucent materials as well as a real-time rendering technique leveraging graphics hardware. This allows users to quickly create translucent organic tissues without the need of complex acquisition system nor an extensive knowledge of the equations underlying the subsurface scattering phenomenon. Based on this material description and rendering method, we also introduce a method for mimicking human irides, which only requires iris photographs and a small involvement of the user.La diffusion sous surfacique a été, ces dernières années, un sujet de recherche particulièrement prolifique. Le but de ce domaine de recherche est de simuler de manière plus ou moins précise les interactions entre la lumière et les particules constitutives d'un matériau. Cette thèse présente une nouvelle méthode de modélisation ainsi qu'une technique de rendu temps réel pour les matériaux organiques complexes. "Subsurface Texture Mapping" est une technique de modélisation simple et intuitive ainsi qu'une méthode de rendu temps réel permettant de créer des matériaux organiques multicouches très rapidement et ce, sans la nécessité d'utilisation d'appareils de capture complexes ou de connaissances préalables des équations qui régissent le phénomène de diffusion sous surfacique. Nous basant sur la description de matériaux organiques préalablement introduite, nous présentons également une méthode permettant d'imiter l'iris humain. Cette méthode, semi-automatique, est basée sur de simples macrophotographies et ne requiert qu'une faible implication de l'utilisateur.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF