Shih_Image_Processing_and_Mathematical_Morpholo.pdf

Introduction to Mathematical Morphology 3
FIGURE 1.1 Image digitization.
image can produce a checkerboard effect or graininess. When an image of
1024 ¥ 1024 is reduced to 512 ¥ 512, it may not show much deterioration, but
when further reduced to 256 ¥ 256 and then rescaled back to 1024 ¥ 1024, it
may show discernible graininess.
The visual quality requirement of an image depends upon its applications.
To achieve the highest visual quality and at the same time the lowest
memory requirement, one may perform fi ne sampling of an image at the
sharp gray-level transition areas and coarse sampling in the smooth areas.
This is known as sampling based on the characteristics of an image [Damera-
Venkata et al. 2000]. Another method known as tapered quantization
[Heckbert 1982] can be used for the distribution of gray levels by computing
the occurrence frequency of all allowable levels. The quantization level
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FIGURE 1.2 A digital image and its numerical representation.
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