Fresnel Correction of the Beckmann Model

نویسندگان

  • Hossein Ragheb
  • Edwin R. Hancock
چکیده

In this paper we suggest a modification to the Beckmann-Kirchhoff model of rough surface reflectance that can be used for surfaces of intermediate roughness. One of the problems with the existing Beckmann model is that it fails for large angles of incidence. This problem was overcome for rough surfaces by Vernold and Harvey who use a Lambertian form factor. Here we take this work one step further by using a Fresnel coefficient to account for subsurface reflectance attenuation. This study also aims to show the existing modelling gaps between different variants of the Beckmann model.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Testing new variants of the Beckmann-Kirchhoff model against radiance data

In this paper, we explore whether the Fresnel term can be used to improve the predictions of the Beckmann–Kirchhoff (B-K) model for moderately rough surfaces. Our aim in developing this model is to describe subsurface scattering effects for surfaces of intermediate roughness. We use the BRDF measurements from the CUReT database to compare the predictions of the Fresnel correction process with a...

متن کامل

Comparing Variants of the Beckmann Model

Abstract Recent work has shown how the Fresnel coefficient can be used to improve the predictions of the Beckmann-Kirchhoff (BK) model for moderatelyrough surfaces. This paper aims to compare the predictions of a number of alternative models including those of Lafortune et al. (LFTG) and Oren-Nayar (ON) against the BRDF measurements from the CUReT database. Excluding the specular reflectance co...

متن کامل

Designing the optimal Fresnel lenses by using Zemax software

In this paper, the optimal Fresnel lenses are designed by Zemax software.The fundamental problem of the Fresnel lenses is the beam divergence, which wasresolved by decreeing the output stain diameter on the image plane. For this purpose,two types of radial and cylindrical Fresnel lenses are simulated with different groovesusing Global and Hammer optimization methods. The minimum output stain di...

متن کامل

Nano SiO2/H2SO4 as catalyst for the Beckmann rearrangement and deoximation of aldoximes

Nano silica-H2SO4 is an efficient and mild catalysis system for the regeneration of aldehyde from aldoximes. Ketoximes are converted to amides by Beckmann rearrangement in the presence of nano silica-H2SO4. The reactions are carried out in solvent-free conditions under microwave irradiation (600 W) within 50-120 sec in good yields.

متن کامل

Rough Surface Analysis using Kirchhoff Theory

In this paper we illustrate the use of the Beckmann-Kirchhoff model for analysing rough surface reflectance. The Beckmann-Kirchhoff model is a physical model that describes the reflectance of light from rough surfaces. The parameter of the model is the surface slope, or ratio of the surface roughness to the correlation length. We show how this parameter may be estimated using pairs of surface i...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2004