Game Development Reference
In-Depth Information
Figure 4. By using snakes, face and feature contours are tracked on each
frame of the sequence. Images courtesy of the Image Processing Group at
the Universitat Politècnica de Catalunya.
In general, the energy function can be decomposed into two terms, an internal
energy and an external energy:
E
=
E
+
E
.
(3)
total
int
ext
The role of the external energy is to attract the point of the snake towards the
image contours. The internal energy tries to ensure certain regularity on the
snake while
E
ext
acts, from a spatial as well as from a temporal perspective. Once
the energy function is defined, we use an iterative process to find its minimum.
We can understand the minimum energy point as the equilibrium position of a
dynamic system submitted to the forces derived from the energy functions.
Mathematical morphology — Edge detection & segmentation
When analyzing images of faces under unconstrained conditions, classical image
filtering techniques may not be robust enough to extract all the information from
them.
Mathematical morphology appeared as an alternative mathematical tool to
process an image from a visual perspective, instead of from a numerical one. The
techniques for mathematical morphology are based on set-theoretic concepts
and non-linear superposition of signals and images. Morphological operations
have been applied successfully to a wide range of problems including image
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