Hervé Troadec, Abdesslam Benzinou, Vincent Rodin and Jean Le Bihan.
Use of deformable template for two-dimensional growth ring detection
of otoliths by digital image processing: Application to plaice
(pleuronectes platessa) otoliths.
Fisheries Research, Elsevier, 46(1-3):155-163, May 2000.
Abstract:
Today, most computer-assisted age reading software is limited to
one-dimensional processing. Automated two-dimensional growth ring
detection is closely linked to the ability of image processing
algorithms to perceive structure continuity. By using deformable
models, based on closed B-splines, it is possible to fit a shape
to the image features using maximum or minimum criteria according
to the nature of translucent or opaque zones. Otolith edge contours
were used as templates that were inflated from the core toward the
edge in order to detect the growth zones. Template step sizes were
modulated by an a priori growth pattern in order to take into account
the decrease in ring size.
A reference test image set (n=102) of plaice otoliths, previously aged
by one reader, was processed. For the first age groups, there was a total
agreement with reader estimates. Mean agreement with reader estimates for
age groups 1-5 averaged 80% but decreased for age groups 6-8.
Overall, age was significantly underestimated by an average of -0.89 year.
Keywords:
Fish, Age, Otolith, Computer-assisted, Image, Deformable template,
Pleuronectes platessa.
[doi:10.1016/S0165-7836(00)00142-9]
[Troadec00a.pdf]