![](bg3.png)
For example, Line-ad is used in the rectangle-2Lv2
only once, and the Line-bc is used twice in the
rectangle-2Lv2 and the rectangle-2Lv7, their Draw
value being one & two respectively. Two connecting
lines at the Connection point have an angle between
them, gauged by the trigonometric functions.
3.3 Inference of Shape
When an agent perceives a target object that is
partially blocked by other objects or partially out of
the vision, she would use inference to complete her
perception. Figure 4 shows the information on the
Boundary lines for the shape being inferred (red
boundary of ID: 2LV7 shape). In the information,
we can find two sections (the red rectangle) on the
rapidly changing line’s length (L) and line’s angle
(A). The agent reforms her inferring only when the
target shape is not a regular shape, and its available
amount of information is to exceed minimum. An
agent excludes those rapidly changing parts and
starts her inferring with the rest of the information
on the image to find its closed regular shapes. And
the agent draws virtual lines starting from Junction
points. If it is judged to be a regular shape based on
the virtual lines, she adds the information on the
virtual lines to her original information.
Figure 4: Inferable shape and its Boundary Lines.
4 SPATIAL RELATIONS AMONG
SHAPES
With the shape type identified before, we now
identify the spatial relations existent among those
shapes to achieve a complete recognition. Defined
spatial relation in perception is different with the
recognition’s relation. The spatial relations as
perceived could be specialized into to diverse spatial
relations in recognition. We’ll follow the relations
set of HSR for our recognition (Choe and Park 2005).
For example, relations of HSR include among others
associated with ‘Touch’ in perception, ‘straddling’,
‘hanging’, ‘leaning’. In short, the relations of
perception are redefined again.
4.1 Connection among Shapes
If there is a connection among shapes, shape-A
based relation of shape-B is expressed in the
database on the ontology.
Table 1: Types of Connection.
Connection Defined rule
In The case when central point of B insides
boundaries of A. Only, The inference of A
does not occur by B
Out The case when central point of B outside
boundaries of A. Only, The inference of A
does not occur by B
Touch The case when B and A have shared lines
of the above one. Only, The inference does
not occur by shared lines.
Behind The case when B and A have shared lines
of the above one. And the inference occurs
by shared lines. In this case, The
connection of shape A is Touch and shape
B’ connection is Behind
The Out relation occurs only when the Out Touch
has been found. We mention only because there are
numerous Out relations including the Out touch.
From Table 1, the central point of shapes, shape’s
boundaries and their inference are determinant of
connection between them. These connections are
designed in the ontology and are stored in database.
When there are some additional connections (i.e.
repetition, symmetry and reverse etc.), this data
structure can be used to solve the problem by adding
proper rules in the ontology.
4.2 Direction among Shapes
The Direction is another parameter to special the
spatial relations. The Direction uses a shape’s
central point as the reference. For example, ‘direct3
out touch', means a shape has an Out relation on the
3:00 direction with another shape. Figure 5 shows
the coordinate for area. Central circle is called
Center relation. Other Coordinates proceed in order
clockwise. Various spatial relations could be defined
indicates by combining Connection and Direction.
A PERCEPTION MECHANISM FOR TWO-DIMENSIONAL SHAPES IN THE VIRTUAL WORLD
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