Transcript GPIS

GP-based Image
Segmentation (GPIS)
with
Applications to Biomedical
Image Segmentation
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Problem statement
• How do we select an optimal sequence of
low-level image operators (& parameters)
to get the segmented image?
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Segmentation example: cell nuclei
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
…
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Model description
• We use Cartesian GP:
– Primitive operators are clearly defined, their
right combination is the problem
– CGP allows for an easy interpretation of the
resulting sequence
– Segmentation is a class of problems without
one perfect solution; CGP can handle this
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
System objectives
• Effectiveness: segmentation should be
correct
• Efficiency: The smallest number of
operations
• Transparency: operation sequences
should be easy to understand
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
System objectives (cont.)
• Segmentation should be doable without a
priori information (except for training
ground truths)
• Generality: effective on wide classes of
images
• Ease of Use: Minimal human intervention
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Fitness criterion
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Fitness criterion
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Fitness criterion
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Crossover
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Mutations (I)
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Mutations (II)
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Data
1026 images, 512 x 384
pixels
120 images, 340 x 780
pixels
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
System settings, database 1
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Pixel segmentation accuracy,
database 1
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Cell segmentation accuracy,
database 1
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Statistical results, database 1
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Example of evolved program,
database 1
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Example of evolved program,
database 1
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
System settings, database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Pixel segmentation accuracy,
database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Cell segmentation accuracy,
database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Statistical results, database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Example of evolved program,
database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Intermediate steps of evolved
program, database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Intermediate steps of evolved
program, database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Intermediate steps of evolved
program, database 2
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Superimposed input + evolved program
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
GPIS on other types of images
Lane detection
tree detection
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
GPIS on other types of images
Intra-cellular content of Wright-stained white blood cell
images
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Conclusion
• CGP was able to adapt to the complexity
of input images:
– A short program was evolved to solve the
easy problem
– a longer program was evolved to solve the
harder problem
• Operator pool can be extended with
specialized operators
• Injection was a reliable means of
maintaining population diversity
(c) Louis Charbonneau and Nawwaf
Kharma, 2009
Conclusion
• A training window approach is very
effective for operator refinement
• A small but accurate set of ground truths
is enough to evolve segmentation
algorithms without a priori information on
the images
(c) Louis Charbonneau and Nawwaf
Kharma, 2009