Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

4 Machine Graphics and Vision

Znaleziono wyników: 4

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Interactive volume rotation

100%

Csebfalvi B. , Szirmay-Kalos L.

tom Vol. 7, No. 4

793-806

In this paper a new volume rendering method is presented which provides real-time rotation without using any acceleration hardware. The algorithm is based on the efficient handling of empty voxels, where according to the opacity values a 3D binary mask is generated indicating the locations of the non-transparent voxels. Ray casting is performed on this binary mask which is rotated rapidly by shear-warp factorization and an incremential aligment technique. The location of non-zero bit hit by a ray is mapped onto the corresponding voxel location in the orginal classified volume, in order to get the opacity and color values in the given samples point. The technique proposed for rotating and sampling the binary mask exploits only the standard ALU operations providing interactive frame rates even on low cost machines.

Non-diffuse, random-walk radiosity algorithm with linear basis functions

80%

Szirmay-Kalos L. , Foris T. , Purgathofer W.

tom Vol. 7, No. 1/2

475-484

This paper presents an efficient method to solve the general rendering equation, using a combined finite element and quasi-random walk approach. Applying point collocation method, the surfaces are decomosed into planar patches where the directional distribution of the radiance is assumed to be a linear combination of the disrtibutions at the vertices. The direction dependet radiance function of the vertces is then computed by random of quasi-random walk.

Reflectance models by pumping up the albedo function

80%

Neumann L. , Neumann A. , Szirmay-Kalos L.

tom Vol. 8, No. 1

3-17

The paper introduces a method, called the albedo pumping-up, to derive new, physically plausible BRDFs from an axisting one or from any symmetric function. This operation can be applied recursively arbitrary number of times. An important application of this operation is the transformation of the Phong and Blinn models in order to make them produce metallic effects. The paper also examines the albedo function of reflectance models and comes to the conclusion that widely used models violate energy balance at grazing angles.

Quadratic shading and its hardware implementation

80%

Abbas A. M. , Szirmay-Kalos L. , Horvath T. , Foris T.

Machine Graphics and Vision

2000

tom Vol. 9, No. 4

825-839

Rendering systems often represent curved surfaces as a mesh of planar polygons that are shaded to restore a smooth appearance. Gouraud shading uses linear color interpolation and its hardware implementation is relatively easy, but it handles specular highlights incorrectly and introduces annoying artifacts called Mach banding over the edges of the polygon mesh. In software rendering, Phong shading has been more popular, because it can realistically handle specular materials. Since it requires the rendering equation to be evaluated for each pioxel, its hardware support poses problems. This paper presents a nonlinear, i.e. quadratic interpilation scheme which is in between Gouraud shading and Phong shading. It can also be implemented by hardware means as Gouraud shading, but its shading quality is comparable with that of the Phong shading. A software simulation and VHDL description of the shading hardware are also presented.