In: Paparoditis N., Pierrot-Deseilligny M.. Mallet C. Tournaire O. (Eds). 1APRS. Vol. XXXVIII. Part ЗА - Saint-Mandé, France. September 1-3, 2010
6. CONCLUSION
In this paper, we have applied a powerful MCS to combine
statistical and neural classifiers based on the FMV. To test the
algorithm, three different classifiers based on four datasets of
different sensor and scene characteristics were applied. The
results showed an improvement in terms of overall
classification accuracy and omission and commission errors of
individual classes. Average overall accuracies of individual
algorithms were 96.75%, 95.9% and 93.7% for SVMs, SOM
and CTs respectively whereas the proposed fusion algorithm
gives an accuracy of 97.85% which is an improvement of
around 1.1%. This is an enhancement considering the limited
room for improvement beyond 96.9% accuracy achieved with
the SVMs, and that the data are most likely subject to other
errors in image acquisition and image to lidar geographic
registration, as well as errors in filtering of lidar point clouds.
On the other hand, the average commission and omission errors
have been reduced compared to the best single classifier. A
comparison of the results with some of the existing fusion rules
such as Maximum Rule (MR) and Weighted Sum (WS),
demonstrates that the proposed fusion algorithm gives the best
results. The computational cost involved in implementing the
combined classifiers based on the FMV method is much higher
than that of MR and WS methods. However, the processing
time could be reduced by splitting large test areas into smaller
parts, processing each part separately and combining the results
later. For example, dividing the Fairfield test area, which is
4km* in area, into four equal parts can saved more than 85 % of
processing time (from 390 s to 58 s). The results in this paper
demonstrate the overall advantages of the proposed fusion
algorithm for combining multiple classifiers.
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ACKNOWLEDGEMENTS
The authors wish to acknowledge AAMHatch for the provision
of the UNSW and Fairfield datasets, the Land Property
Management Authority (LPMA), NSW. Australia for Bathurst
data sets and the Toposys GmbH, Germany for the Memmingen
datasets.