Information Technology Reference
In-Depth Information
Figure 6.12.
The four interpretations of the polyhedral object
-
E
F
E
F
+
+
D
D
+
K
+
K
+
+
-
J
J
C
C
-
-
+
+
B
I
B
I
+
G
+
G
+
+
A
H
A
H
E
F
E
F
+
+
-
D
D
+
K
+
K
+
+
-
J
J
C
C
-
-
+
+
-
B
I
B
I
+
G
+
G
-
+
+
-
-
A
H
A
H
also that there is no interpretation where the object is against a wall behind it
and
to
the left, as this would require vertex E to be a fork.
The object depicted in figure 6.7 is
almost
unambiguous. Once the boundaries of the
object are determined, which a low-level visual process may be able to do based on
differences in color or brightness between the object and the background, everything
else falls into place. But this still depends on putting all the constraints together. For
example, if you cover the top and right parts of the figure, you can (with a bit of
effort) come to see the surface CDKJ as being closer than ABIH, where the edge CJ is
now convex. Globally, however, this interpretation is unsustainable.
