Image Processing Reference
In-Depth Information
FIGURE 7.17: A digital wheel-thrown uni-voxel thick bowl created by an
irreducible digital curve segment as the digital generatrix. The surface is then
decomposed into quads for texture mapping with suitable illumination and
shadow formation. (See color insert.)
Reprinted from
International Journal of Arts and Technology
,
4
: 196-215, G. Kumar et al., Copyright 2011, with
permission from Inderscience Publishers.
7.2.6 Some Examples
Snapshots of some example potteries, taken from [125], are given in
Figs. 7.16, 7.17, and 7.18. These are generated by a software developed by
the authors of [125] in Java3D
TM
API, version 1.5.2. Figure 7.16 shows how a
digitally connected and irreducible surface of revolution (Sec. 7.2.2) is decom-
posed into appropriately small quads in accordance with Eq. 7.8 for subsequent
texture mapping (Sec. 7.2.5). The irreducible digital surface in Z
3
, which is
an ordered set of voxels, is mapped to the corresponding real surface in R
3
for quad-decomposition, which is quite fast, e
cient, and bug-free by dint of
the very property of connectivity and irreducibility of the digital surface of
revolution.
Fig. 7.17 shows another result for a “
bowl
” with a relatively larger zoom
factor. When a texture is mapped onto the surface in R
3
, we get a flawless sur-
face resembling a real-world pottery, although uni-voxel thick. A thick-walled
set of potteries, created out of double-layered digital generatrices (Sec. 7.2.5),
is shown in Fig. 7.18. In this model, potteries of varying colors and textures
can thus be developed as per requirement.
Some statistical figures and CPU times to generate a few potteries are
presented in Table 7.1. The total CPU time required to create a digital pottery
consists of two parts: T
1
and T
2
. The time T
1
is for constructing the digital
surface S
G
from a given digital generatrix, G, and the time T
2
is for quad-
decomposition, followed by texture mapping coupled with necessary rendering.
The number of voxels constituting S
G
not only increases with the length of G
