The advantages of representing objects in images as fuzzy spatial
sets are numerous and have lead to increased interest for fuzzy
approaches in image processing. Fuzziness is an intrinsic property of
images. It is additionally introduced in digital image processing by
discretization, and as a natural outcome of most imaging devices.
The fuzzy membership of a point reflects the level to which that
point fullfils certain criteria to belong to the object; the
membership of a pixel is often determined to be proportional to the
part of the pixel area covered by the observed object. Preservation
of fuzziness implies preservation of important information about
objects and images. Therefore, fuzziness should, in general, be kept
and utilized as long as possible when analyzing the image data.
The intention is to, first, give a brief introduction to the fuzzy
set theory, and then, to discuss some of its applications to image
analysis. Fuzzy segmentation methods and fuzzy shape analysis
techniques are in focus. Several ways to incorporate fuzzy methods
in segmentation process, and also ways to represent objects in
images as fuzzy sets, are discussed. Methods to generalize
well-known concepts, like perimeter and area of a set, or distance
between elements of a set, from crisp to fuzzy sets, are explained.
It is shown that, by using fuzzy approaches, an improved precision
of some shape description can be achieved. In addition, some
defuzzification approaches, that are used to reduce fuzzy sets to
their crisp representatives, are presented, and their properties
discussed.
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