## Presentation examensarbete

It also produces very high quality renderings.

The data could represent anything from weather measurements to abstract mathematical data.

The scale that can be seen on bottom represents the density values of the data in Hounseld units, HU, which is the standard unit in CT-scanning named after the inventor of CT-scanning, Sir Godfrey.

5.1 Local Illumination The primary task was to improve quality, and the solution that lay at hand was to incorporate a local illumination model.The idea rabatt sj pensionär was introduced 1993, in a paper by Cullip and Neuman CN93, and is illustrated in gure.1.Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning.När du skriver på avtal läs igenom noga och tänk på vad du skriver under.

The description generally refers to some sort of surface representation, such as a polygon mesh.

However, enabling the application to render a 5123 voxels data set should be straightforward, since the latest graphics cards, such as the Nvidia GeForce 7800, support volume textures of that size.

The textures are easily created by rendering a simple cube, with each pixel colored with the X,Y,Z of the geometric position.

7.1 Proxy Geometry The implementation of the local illumination model, Blinn-Phong illumination, improved the quality of the rendering signicantly, and the bricking algorithm proved to enable the loading of larger data sets (the largest data set tested was 5123 voxels).

However, in volume rendering there are no real surfaces, only so-called isosurfaces, surfaces within the volume data with constant value.21.5 Stream Program Model.The size of the individual small cubes that together form the bounding geometry is naturally vital for performance.6.1 Algorithm Overview The actual sampling along the casted rays is relatively simply implemented in a pixel shader, it is merely a lookup in a texture and compositing.45.4.3 Sampling Distance.Slutsats, tack för mig!12 Volume Rendering Figure.6 presents four examples of volume renderings of the same data set but with dierent transfer functions.

Secondly, sizes do matter, and they matter a lot.

I(x, r) L 0 C(s s)e R s 0 (t)dt ds (2.2) The equation calculates the intensity, I, of a certain wavelength, that is received at position x on the image plane from direction.

Since dierent hardware supports dierent levels of programmability, standards are important to simplify both for developers and consumers.