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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
The inheritance hierarchy and the group's hierarchy
complement each other in the following sense. While the
inheritance hierarchy is used to subsequently separate and
differentiate classes of the objects in the feature space, the
group's hierarchy permits the meaningful grouping of the
resulting classes.
The local government, land management and regional
development solve many tasks where the above described
approach is applicable on the different levels in the field of
monitoring, mapping, inventory, change detection or parameters
estimation.
The class hierarchy. and related restrictions and assumptions,
which can be continually changed during the processing, it is
the base of knowledge for the image object classification. In
many applications the desired geo-information and the objects
of interest are than extracted step by step, by iterative process of
classifying and processing. It is very similar to human image
understanding processes.
This kind of circular processing results in a sequence of partial
states, with an increasing differentiation of the classification
result and the increasing abstraction of the original image
information.
On the each step of the abstraction new information and new
knowledge is generated and can be used beneficial for the next
analysis step. High beneficial is the fact, that after successful
analysis, a lot of interesting, additional information can be
derived.
There are many reasons for the knowledge-based spatial data
network building and sharing. The pixel-oriented classification
can be accepted as the pre-processing phase that is followed by
object-oriented contextual classification applied through
decision tree design.
2.2 Decision-making process
The average resolution of image objects can be adapted to the
scale of interest and resulting information can be represented in
the scale based on the average size of image objects. This fact is
coherent with the hierarchical networking and representation of
image objects. In the hierarchical structure each object knows
its neighbours, sub objects and super objects.
—
BÀ d ta
Figure 2. Part of cadastral plan.
We distinguish three types of elemental object features:
Q Attribute (physical properties of objects that follow
from real world or image or different information
layers related to the object).
109
OQ Topological features (describe the geometric
relationships between the objects or the whole scene).
C) Context features (represent the objects’ semantic
relationships. The gardens are inside the urban area;
the island is surrounded by the water, and so on. It
means between class (object) relationships).
Figure 3. Identification of outdoor pools inside the gardens.
The different segmentation techniques can be used to construct
a hierarchical network of image objects and each level in this
hierarchical network is produced by a single segmentation run.
The hierarchical structure represents and contains the
information of the image data at different resolutions
simultaneously. Fine objects are sub-objects of the coarser
structures. It means, that each object knows its context, its
neighbourhood and its sub-objects.
3. FUZZY DESIGN
3.4 Membership function design
Each of the decision-making process is associated with some
level of overall uncertainty. Human experience is often
expressed using the expressions like: a little bit more, more than
usual, less than last time, etc.
This uncertainty can rise from the facts that:
QO We are not able to define exactly the problem, the
class of objects.
Q We utilize not quite correct spatial data with respect
to define task.
Q We are not able to verify all assumptions, and
estimate and validate all restrictions we need to build
out the hierarchical decision model.
The automation of the classification and interpretation process
gives better results when the fuzzy elements are implemented
into the decision structure.
One of the well-known approaches to decision making based on
uncertain information is Fuzzy Logic. This framework is
frequently used for decision making in case when the expert
knowledge and rules are to be implemented into the decision
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