Comparison of different Segmentation Techniques
S.No Segmentation
Technique
Information
used in
Segmentation
Extends
to N-D
Method of
Segmentation
Advantages Disadvantages
1 Thresholding Colour No Simple
Comparison
Between
Pixels And
The
Threshold
When the intensity of the
pixels is larger/smaller than a
predefined threshold, those
pixels are classified as
foreground. Otherwise, they
will be viewed as
background.
Threshold based approaches
are the simplest, easiest and
fast ones among all of the
existed segmentation
methods.
The difficulty is that it is
not easy to find an
appropriate threshold
which can separate the
image into two groups
directly.
This method also requires
the foreground and
background in the image
have obviously different
intensity values.
2 Live Wire Edge No 2D Graph
Search Using
Dynamic
Programming
More general, reduced
initialization.
Real-time: User immediately
sees whether desired contour
was obtained or not and can
adjust contour otherwise.
Direct control of contour.
Sub-pixel accuracy not
possible.
Contour depends on
weighting between internal
and external costs.
May ignore jagged edges
or snap to wrong edges.
3 Snakes/Activ
e contours
Edge No Energy
Minimization
of Internal
and External
Functions
They autonomously and
adaptively search for the
minimum state.
External image forces act
upon the snake in an intuitive
manner. Incorporating
Gaussian smoothing in the
image energy function
introduces scale sensitivity.
They can be used to track
dynamic objects.
They are sensitive to local
minima states, which can
be counteracted by
simulated annealing
techniques. Minute
features are often ignored
during energy
minimization over the
entire contour.
Their accuracy depends on
the convergence policy.
4 Graph cut Colour and
Edge
Yes Max-
Flow/Min-
Cut
Algorithm
For Energy
Minimization
The energy function is
constructed based on regional
and boundary information and
it can achieve globally
optimal result.
Taking the sorce and sink
points and grouping the
points into source region
and sink region
automatically with out
human interaction is
difficult.
