605
In: Wagner W., Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B
coniferous tree species group since the presence of the
deciduous trees is more easily recognizable in the aerial images.
Despite the theoretical advantages of the segment-based
approach, the features extracted for segments did not perform
well in the estimation procedure. There are some possible
reasons for this. First, the field data was measured per sample
plots and not per segments. Because of this the areas of the field
measurement and the extracted remote sensing features
correspond to each other best in the feature set Grid.
Furthermore, the automatic segmentation often produces
segments that are irregularly shaped, i.e. not compact, and in
forest stands with large trees the segment borders are typically
located in gaps between trees, in which case the variation within
the segments may be more significant than the variation
between segments. On the other hand, using geographically
larger segments in extracting the features typically resulted in
lower estimation accuracy compared to other feature sets, which
indicates that the larger the units are the more internal variation
they have.
Based on the results of this study the most feasible inventory
procedure utilizing ALS and aerial image data seems to be the
following: 1) estimation based on ALS data and aerial imagery
for the systematic grid elements, 2) automatic segmentation
utilizing ALS height, ALS intensity and aerial imagery, 3)
deriving the estimates for image segments on the basis of the
estimates of grid elements and 4) manual combination of image
segments for deriving spatial units for forest management
purposes.
Forestry Sciences, vol. 76. (pp. 111-123). Kluwer Academic
Publishers.
Suvanto, A., Maltamo, M., Packalen, P. and Kangas, J., 2005.
Kuviokohtaisten puustotunnusten ennustaminen
laserkeilauksella. Metsdtieteen aikakauskirja, 4/2005, 413-428.
Tokola, T., Pitkanen, J., Partinen, S. and Muinonen, E., 1996.
Point accuracy of a non-parametric method in estimation of
forest characteristics with different satellite materials.
International Journal of Remote Sensing, Vol. 17, No. 12, pp.
2333-2351.
ACKNOWLEDGEMENTS
The authors wish to thank M.Sc. Risto Viitala at the HAMK
University of Applied Sciences and Lie.Sc. Juho Heikkila at
Forestry Development Centre Tapio for providing the field and
remote sensing materials for this study.
4. REFERENCES
Haralick, R., 1979. Statistical and structural approaches to
texture. Procedings-IEEE, 67(5), 786-804.
Haralick, R. M., Shanmugan, K. and Dinstein, L, 1973. Textural
features for image classification. IEEE Transactions on
Systems, Man and Cybernetics, SMC-3(6), 610-621.
Hyvonen, P., Pekkarinen, A. and Tuominen, S., 2005. Segment-
level stand inventory for forest management. Scandinavian
Journal of Forest Research 20(1), 75-84
Kilkki, P. and Pâivinen, R., 1987. Reference sample plots to
combine field measurements and satellite data in forest
inventory, Department of Forest Mensuration and
Management, University of Helsinki, Research Notes, 19:210-
215.
Mustonen, J., Packalén, P. and Kangas, A., 2008. Automatic
segmentation of forest stands using a canopy height model and
aerial photography. Scandinavian Journal of Forest Research
23(6): 534-545.
Narendra, P. and Goldberg, M., 1980. Image segmentation with
directed trees. IEEE Transactions on Pattern Analysis and
Machine Intelligence. Pami-2: 185-191.
Pekkarinen, A. and Tuominen, S., 2003. Stratification of a
forest area for multisource forest inventory by means of aerial
photographs and image segmentation. In P. Corona, M. Kohl, &
M. Marchetti (Eds.), Advances in forest inventory for
sustainable forest management and biodiversity monitoring.