Jeppe Revall Frisvad

Jeppe Revall Frisvad

Associate Professor in Computer Graphics, M.Sc.(Eng.), Ph.D.
Image Section
DTU Compute
Technical University of Denmark
Contact information
Curriculum Vitae (CV)

Code Packages
Press Appearances

Research Projects

Digital Prototypes
Co-applicant. Project funded by the Danish Council for Technology and Innovation (Resultatkontrakt).

Desktop Scientific Computing (GPUlab)
Co-applicant. Project funded by the Danish Council for Independent Research - Technology and Production Sciences (FTP).

Center for Imaging Food Quality (CIFQ)
Participant. Project funded by the Danish Council for Strategic Research.

Recent and Upcoming Publications

Abildgaard, O. H. A., Kamran, F., Dahl, A. B., Skytte, J. L., Nielsen, F. D., Thomsen, C. L., Andersen, P. E., Larsen, R., and Frisvad, J. R. Non-invasive assessment of dairy products using spatially resolved diffuse reflectance spectroscopy. Applied Spectroscopy, 2015. To appear. [abstract]
Frisvad, J. R., Hachisuka, T., and Kjeldsen, T. K. Directional dipole model for subsurface scattering. ACM Transactions on Graphics 34(1), pp. 5:1-5:12, November 2014. To be presented at SIGGRAPH 2015. [abstract/demo] [code]
Nielsen, J. B., Frisvad, J. R., Conradsen, K., and Aanæs, H. Addressing grazing angle reflections in Phong models. ACM SIGGRAPH Asia 2014 Posters, November 2014. [abstract]
Frisvad, J. R., Schjøth, L., Erleben, K., and Sporring, J. Photon differential splatting for rendering caustics. Computer Graphics Forum 33(6), pp. 252-263, September 2014. [abstract]


02560 Web Graphics and Scientific Visualization (since Autumn 2014)
Course responsible and course designer. Graduate course taught for the M.Sc. education in Digital Media Engineering and Mathematical Modelling and Computation.
This course uses a flipped learning model (exercises first, lecture later).

02562 Rendering - Introduction (since Autumn 2011)
Course responsible.

02525 Introduction to Mathematics and Technology (since Autumn 2010)
Course responsible. Freshman course taught for the B.Sc. education in Mathematics and Technology.

02576 Physically Based Rendering
Course designer. This course will no longer run regularly, but may run on demand as a PhD course.

Code News

December 2014
WebGL example of my onb method. It is here used to generate a consistently oriented tangent space.

October 2014
WebGL example of our directional dipole for subsurface scattering is now available.
It acompanies the abstract of our paper to appear in ACM Transactions on Graphics.

June 2014
dirpole code has been released.
This is a simplistic example implementation of our directional dipole model for subsurface scattering.
It accompanies a publication to appear in ACM Transactions on Graphics.

June 2013
LMabs code has been published in a Matlab version.
This is code for computing the scattering properties of participating media using Lorenz-Mie theory.
It accompanies a publication that appeared in ACM Transactions on Graphics (Proceedings of ACM SIGGRAPH 2007).

May 2013
02576 Rendering Framework has been updated substantially for the 2013 version of the course 02576 Physically Based Rendering.

May 2012
GPU FFT code had a subtle bug which has been fixed.
This bug fix has been propagated to all online versions of the FFT code (gpu_fft, fft_demo, gpu_convolution, convolution_demo, glare_demo).

May 2012
onb code has been updated as I found a speed up for one of the methods that the new approach is compared against.

April 2012
onb code has been published on the code packages page.
This code is for building an orthonormal basis from a 3d unit vector without explicit normalization.
It accompanies a publication in Journal of Graphics Tools.

Lorenz-Mie Theory: Translation Project

There has been much discussion and many misunderstandings about the work of the remarkable Danish scientist Ludvig Lorenz (1821-1891) on the theory of light scattering of a plane wave by a spherical particle. This theory is often referred to as Mie theory. In "The Scattering of Light and other electromagnetic radiation", Academic Press, 1969, Kerker presents a historical investigation of the origins of the theory and concludes:

It is not the intention of this author to arbitrate the questions of priority raised here nor to identify the theory of scattering by a sphere with any one man's name. Indeed, coincident and consecutive discoveries are common occurrences in science. But certainly if this theory is to be associated with the name or names of individuals, at least that of Lorenz, in whose paper are to be found the practical formulas so commonly used today, should not be omitted.

Nevertheless, some authors prefer to call it Mie theory rather than Lorenz-Mie theory. Perhaps because of the widespread supposition that Lorenz's theory relies on the existence of an ether. Reading the first pages of Lorenz's article, it is clear that this is certainly not true (see the translation below). Lorenz explicitly states that light propagation is like the laws for transmission of electricity and electrical forces and that this differs from the theory of elasticity. To uphold the recommendation that the theory of scattering of a plane wave by a spherical particle should continue to be called Lorenz-Mie theory, I am working on a translation of Lorenz's pioneering article from 1890.

Unfortunately, I have only very little time to work on this project. In truth, I have not been able to find time to work on it since 2011. Since progress is slow, I want to make the translation available even though it is still unfinished. The original article is:

Lorenz, L. Lysbevægelser i og uden for en af plane Lysbølger belyst Kugle. Det kongelige danske Videnskabernes Selskabs Skrifter, 6. Række, Naturvidenskabelig og Mathematisk Afdeling VI, 1, pp. 2-62.

It is 61 pages. The translation follows the original page numbering. So far, I have translated 17 pages. There is still some way to go, but here is the partial translation:

Lorenz, L. Light propagation in and outside a sphere illuminated by plane waves of light. Det kongelige danske Videnskabernes Selskabs Skrifter, 6. Række, Naturvidenskabelig og Mathematisk Afdeling VI, 1, pp. 2-62. Translated by Jeppe Revall Frisvad, pp. 2-19, 2011 (unfinished).

In an old Danish Biographical Encyclopedia, the following interesting paragraph about this article appears. Translated from Danish:

Lorenz's work on the Theory of Colour Dispersion (Videnskab. Selsk. Skrifter 6. R. II, 1883) is particularly important as it is the outset of his solution of the old famous rainbow problem. The outlines of the rainbow theory are given by Descartes and Newton, more completely by Airy, who explained the supernumerary arcs by light interference. But, while one had previously limited oneself significantly to determining the directions in which these arcs appear, Lorenz set himself the goal to determine the light intensity completely in all directions on the basis of the theory of light. To complete this task, Lorenz worked almost continuously for several years; the dissertation is available in Videnskab. Selsk. Skrifter 6. R. VI (1890).